LIQUID DISCHARGE APPARATUS

Abstract

 A liquid discharge apparatus (1) includes a head (100) to discharge a liquid; a circulation passage (500) coupled to the head (100), through which a temperature-controlled liquid circulates; a radiator (511) including a fan (511a), to cool the temperature-controlled liquid; a head drive board (160) mounted with a power amplification unit (161) to amplify a drive waveform applied to the head (100); an ambient temperature sensor (811) to detect an ambient temperature of the radiator (511); a liquid temperature sensor (812) to detect a temperature of the temperature-controlled liquid at an inlet of the radiator (511); and a controller (801). The controller (801) controls at least one of a rotation of the fan (511a) and a heating waveform applied to the head drive board (160), based on a target temperature of the temperature-controlled liquid, the ambient temperature of the radiator (511), and the temperature of the temperature-controlled liquid at the inlet of the radiator (511).

Description

Technical Field

[0001] The present disclosure relates to a liquid discharge apparatus.

Description of the Related Art

[0002] A liquid discharge apparatus includes a head to discharge a liquid and components that generate heat (heat generators). Examples of the heat generators include a pressure generator, such as a piezoelectric element, to generate pressure to discharge the liquid, a driver integrated circuit (IC), such as a switching circuit, and a head drive board disposed adjacent to the head. The head drive board includes a power amplification unit and generates a drive waveform to drive the piezoelectric element. In the head, the temperature of the liquid to be discharged rises inherent to the heat generated by the heat generators, resulting in fluctuations in liquid discharge properties.

[0003] A conventional structure includes a container for storing a temperature-controlled liquid (cooling liquid) whose temperature is adjusted, means for cooling the cooling liquid in the container, a forward direction manifold through which the temperature-controlled liquid from the container is distributed to a plurality of heads, and a return manifold through which the temperature controlled liquid is collected from the plurality of heads is returned to the container. For example, JP-H10-86411-A discloses such a structure.

[0004] In the structure using the temperature-controlled liquid, controlling the temperature of the temperature-controlled liquid to a target temperature is required for efficient cooling.

SUMMARY

[0005] In view of the foregoing, an object of the present disclosure is to provide efficient cooling in a liquid discharge apparatus.

[0006] In order to achieve the above-described object, there is provided a liquid discharge apparatus as described in appended claims. Advantageous embodiments are defined by the dependent claims.

[0007] Advantageously, the liquid discharge apparatus includes a head configured to discharge a liquid; a circulation passage coupled to the head, through which a temperature-controlled liquid circulates; a radiator including a fan and configured to cool the temperature-controlled liquid; a head drive board mounted with a power amplification unit configured to amplify a drive waveform applied to the head; an ambient temperature sensor configured to detect an ambient temperature of the radiator; a liquid temperature sensor configured to detect a temperature of the temperature-controlled liquid at an inlet of the radiator; and a controller. The controller is configured to control at least one of a rotation of the fan of the radiator and a heating waveform applied to the head drive board, based on a target temperature of the temperature-controlled liquid, a detected ambient temperature of the radiator, and a detected temperature of the temperature-controlled liquid at the inlet of the radiator.

[0008] Accordingly, efficient cooling can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic cross-sectional view of a printer as a liquid discharge apparatus according to a first embodiment of the present disclosure;

FIG. 2 is a plan view of a head unit as a liquid discharge unit of the liquid discharge apparatus as viewed from a nozzle face side;

FIG. 3 is a cross-sectional view of an example of a head along a short-side direction (perpendicular to a nozzle row direction in which a nozzle row extends);

FIG. 4 is a plan view of a temperature-controlled liquid channel taken along the line A-A in FIG. 3;

FIG. 5 is a block diagram illustrating a liquid supply system and a temperature-controlled liquid circulation system according to the first embodiment;

FIG. 6 is a block diagram illustrating a configuration of control of temperature of the temperature-controlled liquid according to the first embodiment;

FIG. 7 is a flowchart illustrating an example of control of temperature of the temperature-controlled liquid performed by a temperature-controlled liquid temperature controller;

FIG. 8 is a table illustrating an example of the relationship between detected temperature and the duty of a head drive board;

FIG. 9 is a table illustrating an example of the relationship between detected temperature and the drive duty of a radiator fan;

FIG. 10 is a schematic diagram of a temperature-controlled liquid circulation system according to a second embodiment of the present disclosure;

FIG. 11 is a schematic diagram of a temperature-controlled liquid circulation system according to a third embodiment of the present disclosure;

FIG. 12 is a block diagram illustrating a liquid supply system and a temperature-controlled liquid circulation system according to a fourth embodiment of the present disclosure;

FIG. 13 is a view illustrating a temperature-controlled liquid supply manifold and a connection between the temperature-controlled liquid collection manifold with heads;

FIG. 14 is a diagram illustrating a configuration of a head unit and a temperature-controlled liquid circulation passage according to a fifth embodiment of the present disclosure;

FIG. 15 is an exterior perspective view of an example of an ink supply manifold;

FIG. 16 is an exterior perspective view of the temperature-controlled liquid supply manifold;

FIG. 17 is a cross-sectional view illustrating the temperature-controlled liquid supply manifold illustrated in FIG. 16;

FIG. 18 is a perspective view illustrating the ink supply manifold and the temperature-controlled liquid supply manifold in an assembled state;

FIG. 19 is a perspective view of a manifold according to a sixth embodiment;

FIG. 20 is a front cross-sectional view of the manifold illustrated in FIG. 19;

FIG. 21 is a front cross-sectional view illustrating a temperature-controlled liquid channel of the temperature-controlled liquid collection manifold;

FIG. 22 is a perspective view illustrating a connection between the temperature-controlled liquid collection manifold and the head drive board;

FIG. 23 is an exploded perspective view of the temperature-controlled liquid collection manifold and the head drive board;

FIG. 24 is a view illustrating relative positions among the head, the temperature-controlled liquid supply manifold, and the temperature-controlled liquid collection manifold; and

FIG. 25 is a plan view of a printer as a liquid discharge apparatus according to a seventh embodiment of the present disclosure.

[0010] The accompanying drawings are intended to depict embodiments of the present invention and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted.

DETAILED DESCRIPTION

[0011] In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner and achieve a similar result.

[0012] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views thereof, embodiments according to the present disclosure are described. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0013] A description is given of a printer as a liquid discharge apparatus according to a first embodiment of the present disclosure, with reference to FIG. 1. FIG. 1 is a schematic cross-sectional front view of the printer according to the first embodiment of the present disclosure.

[0014] A printer 1 includes a loading unit 10 to load a sheet P into the printer 1, a pretreatment unit 20, a printing unit 30, a drying unit 40, an unloading unit 50, and a reversing unit 60. In the printer 1, the pretreatment unit 20 applies, as required, a pretreatment liquid onto the sheet P fed (supplied) from the loading unit 10, the printing unit 30 applies a liquid to the sheet P, thereby performing printing, and the drying unit 40 dries the liquid adhering to the sheet P, after which the sheet P is ejected to the unloading unit 50.

[0015] The loading unit 10 includes loading trays 11 (a lower loading tray 11A and an upper loading tray 11B) to store a plurality of sheets P, feeders 12 (12A and 12B) to separate and feed the sheets P one by one from the loading tray 11, and feeds the sheet P to the pretreatment unit 20.

[0016] The pretreatment unit 20 includes an application device 21 that coats an image formation surface of the sheet P with a treatment liquid having an effect of aggregating a colorant of ink to prevent bleed-through.

[0017] The printing unit 30 includes a drum 31 (a rotator) to carry and convey the sheet P on an outer peripheral surface thereof and a liquid discharge device 32 to discharge the liquid toward the sheet P carried on the drum 31.

[0018] The printing unit 30 includes transfer cylinders 34 and 35. The transfer cylinder 34 receives the sheet P from the pretreatment unit 20 and forwards the sheet P to the drum 31. The transfer cylinder 35 receives and forwards the sheet P conveyed by the drum 31 to the drying unit 40.

[0019] The transfer cylinder 34 includes a sheet griper to grip the leading end of the sheet P conveyed from the pretreatment unit 20 to the printing unit 30. The sheet P thus gripped is conveyed as the transfer cylinder 34 rotates. The transfer cylinder 34 forwards the sheet P to the drum 31 at a position opposite the drum 31.

[0020] Similarly, the drum 31 includes a sheet gripper on the surface thereof, and the leading end of the sheet P is gripped by the sheet gripper. The drum 31 has a plurality of suction holes dispersedly on the surface thereof, and a suction device generates a suction airflow orienting inward from a predetermined suction hold of the drum 31.

[0021] On the drum 31, the sheet gripper grips the leading end of the sheet P forwarded from the transfer cylinder 34, and the sheet P is attracted to and carried on the drum 31 by the suction airflows by the suction device. As the drum 31 rotates, the sheet P is conveyed.

[0022] The liquid discharge device 32 includes discharge units 33 (33A to 33D) to discharge liquids. For example, the discharge unit 33A discharges a liquid of cyan (C), the discharge unit 33B discharges a liquid of magenta (M), the discharge unit 33C discharges a liquid of yellow (Y), and the discharge unit 33D discharges a liquid of black (K). In addition, a discharge unit to discharge a special liquid, that is, a liquid of spot color such as white, gold, or silver, can be used.

[0023] The discharge operation of the discharge unit 33 of the liquid discharge device 32 is controlled by a drive signal corresponding to print data. When the sheet P carried on the drum 31 passes through a region facing the liquid discharge device 32, the respective color liquids are discharged from the discharge units 33, and an image corresponding to the print data is formed.

[0024] The drying unit 40 dries the liquid applied onto the sheet P in the printing unit 30. As a result, a liquid component such as moisture in the liquid evaporates, and the colorant contained in the liquid is fixed on the sheet P. Additionally, curling of the sheet P is inhibited.

[0025] The reversing unit 60 reverses, in switchback manner, the sheet P that has passed through the drying unit 40 in double-sided printing. The reverted sheet P is fed back to the upstream side of the transfer cylinder 34 through a conveyance passage 61 of the printing unit 30.

[0026] The unloading unit 50 includes an unloading tray 51 on which a plurality of sheets P is stacked. The plurality of sheets P conveyed through the reversing unit 60 is sequentially stacked and held on the unloading tray 51.

[0027] Next, an example of a head unit serving as the discharge unit is described with reference to FIG. 2. FIG. 2 is a plan view of the head unit as viewed from a surface of a nozzle plate (i.e., a nozzle face).

[0028] A head unit 300 includes a plurality of heads 100 to discharge a liquid. The heads 100 are in a staggered arrangement on a head mount 302.

[0029] Each head 100 has a plurality of nozzle rows in each of which a plurality of nozzles 104 to discharge liquid is lined (four rows n this example, but the number of rows is not limited thereto).

[0030] Next, an example of the head 100 is described with reference to FIGS. 3 and 5. FIG. 3 is a cross-sectional view of the head 100 along a short-side direction of the head 100 (perpendicular to the nozzle row direction in which a nozzle row extends). FIG. 4 is a plan view of a temperature-controlled liquid channel 130 taken along the line A-A in FIG. 3.

[0031] The head 100 includes a nozzle plate 101 in which the nozzles 104 are formed, a channel substrate 102 that defines channels such as pressure chambers 106 communicating with the nozzles 104, and diaphragms 103 forming walls of the pressure chambers 106, which are sequentially stacked. The head 100 further includes a piezoelectric actuator 111, as a pressure generator, and a frame 120 also serving as a common channel member.

[0032] The piezoelectric actuator 111 includes a plurality of columnar piezoelectric elements 112 on a base 113. The piezoelectric element 112 is joined to the diaphragm 103. A wiring member 115 of a flexible wiring board is connected to the piezoelectric elements 112.

[0033] The frame 120, which also serves as the common channel member, forms a common supply channel 110 to supply the liquid (ink) to be discharged, to the pressure chamber 106.

[0034] To the frame 120, a temperature-controlled liquid channel member 131 is joined. The temperature-controlled liquid channel member 131 defines the temperature-controlled liquid channel 130 through which a temperature-controlled liquid flows in the head 100. The temperature-controlled liquid channel member 131 includes a temperature-controlled liquid supply port 132 to supply the temperature-controlled liquid to the temperature-controlled liquid channel 130, and a temperature-controlled liquid collection port 133 from which the temperature-controlled liquid is discharged outside for collection.

[0035] Accordingly, in the head 100, the common supply channel 110, which is a flow channel for ink, and the temperature-controlled liquid channel 130 are thermally coupled. The frame 120, serving as the casing of the head 100, defines the wall of the temperature-controlled liquid channel 130, and is thermally coupled to the temperature-controlled liquid channel 130.

[0036] On the temperature-controlled liquid channel member 131, a case 150 and a lid 151 are stacked in this order.

[0037] Next, a description is given below of a liquid (ink) supply system and a temperature-controlled liquid circulation system according to the first embodiment, with reference to the block diagram in FIG. 5.

[0038] The ink supply system includes an ink tank 401 (a liquid tank) that stores ink (liquid) to be supplied to the head 100, and an ink supply manifold 402. The ink supply manifold 402 (a liquid supply manifold) distributes and supplies the ink (the liquid) supplied from the ink tank 401 to the plurality of heads 100. The ink supply manifold 402 and the heads 100 are coupled by an ink supply passage 403 such as a tube.

[0039] The temperature-controlled liquid circulation system includes a temperature-controlled liquid tank 501 to store a temperature-controlled liquid 510, a liquid feed pump 502 to feed the temperature-controlled liquid 510, a radiator 511 to cool the temperature-controlled liquid 510, a temperature-controlled liquid supply manifold 505 to distribute and supply the temperature-controlled liquid 510 to the heads 100, and a temperature-controlled liquid collection manifold 506 to collect the temperature-controlled liquid 510 from the heads 100.

[0040] The temperature-controlled liquid supply manifold 505 is coupled to the temperature-controlled liquid supply port 132 of each head 100 by a supply passage 513 such as a tube. The temperature-controlled liquid collection manifold 506 is coupled to the temperature-controlled liquid collection port 133 of each head 100 by a collection passage 514 such as a tube.

[0041] As the liquid feed pump 502 is driven, the temperature-controlled liquid 510 stored in the temperature-controlled liquid tank 501 circulates through the circulation passage 500 that passes through the liquid feed pump 502, the radiator 511 as cooling means, the temperature-controlled liquid supply manifold 505, each head 100, and the temperature-controlled liquid collection manifold 506. Then, the temperature-controlled liquid 510 returns to the temperature-controlled liquid tank 501.

[0042] On a head drive board 160, a drive waveform generation unit that generates a drive waveforms to be applied to the piezoelectric actuators 111 of the plurality of heads 100 and a power amplification unit that amplifies the drive waveforms are mounted. The head drive board 160 is thermally coupled to the temperature-controlled liquid collection manifold 506.

[0043] In the system configured as described above, the liquid feed pump 502 pumps up the temperature-controlled liquid 510 from the temperature-controlled liquid tank 501. Then, the temperature-controlled liquid 510 passes through the radiator 511, and is distributed from the temperature-controlled liquid supply manifold 505 to the heads 100.

[0044] As the temperature-controlled liquid 510 passes through the temperature-controlled liquid channel 130 of each head 100, the temperature-controlled liquid 510 cools the frame 120 of the head 100. After passing through the head 100, while flowing in the temperature-controlled liquid collection manifold 506, the temperature-controlled liquid 510 cools the power amplification unit of the head drive board 160 (a drive circuit), and returns to the temperature-controlled liquid tank 501.

[0045] Meanwhile, the ink is supplied from the ink tank 401 to the ink supply manifold 402 and distributed to each head 100.

[0046] Next, a description is given of the temperature control of the temperature-controlled liquid, with reference to the block diagram in FIG. 6.

[0047] A temperature-controlled liquid temperature controller 801 of the printer 1 receives a result of detection of an ambient temperature T5 of the radiator 511 by an ambient temperature sensor 811. Note that the radiator 511 is disposed outside the printer 1 not to be affected by a temperature rise inside the printer 1, and the ambient temperature T5 of the radiator 511 is the same as the ambient temperature of the printer 1. The ambient temperature sensor 811 is also preferably disposed outside the printer 1.

[0048] The temperature-controlled liquid temperature controller 801 receives detection results from a radiator inlet temperature sensor 812 to detect a temperature (hereinafter referred to as "inflow temperature") T1 of the temperature-controlled liquid 510 at the inlet of the radiator 511 and a radiator outlet temperature sensor 813 to detect a temperature (hereinafter referred to as "outflow temperature") T3 of the temperature-controlled liquid 510 at the outlet of the radiator 511.

[0049] The temperature-controlled liquid temperature controller 801 further receives a detection result from a rotation speed sensor 814 that detects the rotation speed of a fan 511a of the radiator 511.

[0050] Then, the temperature-controlled liquid temperature controller 801 controls the fan 511a of the radiator 511 based on such detection results input thereto.

[0051] Based on the temperature detection results input thereto, the temperature-controlled liquid temperature controller 801 controls application of a heating waveform to the head drive board 160, thereby controlling the heating of the temperature-controlled liquid 510. The head drive board 160 is mounted with a power amplification function (circuitry) for generating a drive waveform for the piezoelectric element 112 and amplifying the waveform and a function (circuitry) for controlling the head 100.

[0052] At this time, the heat generation amount can be controlled by controlling the head drive board 160 and the drive frequency of a drive waveform for heating, applied to the piezoelectric elements 112. For example, when the ambient temperature is 10°C, the head drive board 160 is heated with a heat generation amount of 8 KW (a frequency of 40 KHz), to sharply raise the temperature in the circulation passage 500. As the temperature in the circulation passage 500 reaches an ordinary temperature as the target of ink temperature control, the drive frequency is reduced to reduce the heat generation amount in order to avoid an overshoot.

[0053] Further, the temperature-controlled liquid temperature controller 801 drives the liquid feed pump 502 to circulate the temperature-controlled liquid 510.

[0054] Next, a description is given of the temperature control of the temperature-controlled liquid by the temperature-controlled liquid temperature controller, with reference to FIGS. 7 to 9. FIG. 7 is a flowchart of the temperature control. FIG. 8 is a table illustrating an example of the relationship between the detected temperature and the duty of the head drive board. FIG. 9 is a table illustrating an example of the relationship between the detected temperature and the drive duty of the radiator fan.

[0055] When starting an apparatus start-up process, the temperature-controlled liquid temperature controller 801 determines whether the ambient temperature T5 is lower than 10°C (10°C>T5) or higher than 32°C (32°C<T5) in Step S1 (hereinafter referred to simply as "S1").

[0056] In response to a detection result that the ambient temperature T5 of the radiator 511 is lower than 10°C or higher than 32°C, the temperature-controlled liquid temperature controller 801 displays an alert of out of an operating ambient temperature range (S2).

[0057] On the other hand, in response to a detection result that the ambient temperature T5 of the radiator 511 is equal to or higher than 10°C and equal to or lower than 32°C, the temperature-controlled liquid temperature controller 801 determines whether the ambient temperature T5 of the radiator 511 is lower than 23°C (T5<23°C) in S3.

[0058] In response to a detection result that the ambient temperature T5 of the radiator 511 is lower than 23°C, the temperature-controlled liquid temperature controller 801 performs the following operations, as start-up in a cool environment in S4. Drive the liquid feed pump 502, supply a predetermined voltage (for example, 36 V) to the head drive board 160, and turn on an intermediate potential of the piezoelectric element 112 of the head 100.

[0059] Then, based on the detection result of the inflow temperature T1 at the inlet of the radiator 511, the temperature-controlled liquid temperature controller 801 controls the drive duty (frequency) of the heating waveform of the head drive board 160 for example, as illustrated in FIG. 8 (S5).

[0060] After that, the temperature-controlled liquid temperature controller 801 determines whether or not the inflow temperature T1 at the inlet of the radiator 511 has reached a predetermined temperature (threshold temperature) of, for example, 23°C, or higher (T1≥23°C) in S6. The operation in S5 and S6 is repeated until the inflow temperature T1 reaches the threshold temperature (23°C).

[0061] In response to a detection result of the inflow temperature T1≥23°C, the apparatus enters standby for printing.

[0062] On the other hand, in step S3, in response to a detection result that the ambient temperature T5 of the radiator 511 is not lower than 23°C, that is, the ambient temperature T5 is 23°C or higher, the temperature-controlled liquid temperature controller 801 performs the following as start-up in a hot environment in S7. Drive the liquid feed pump 502, supply a predetermined voltage (for example, 36 V) to the head drive board 160, turn on the intermediate potential of the piezoelectric element 112 of the head 100, and turn on (rotate) the fan 511a of the radiator 511.

[0063] Then, based on the detection result of the inflow temperature T1 at the inlet of the radiator 511, the temperature-controlled liquid temperature controller 801 controls the fan 511a in pulse-width modulation (PWM) control according to the drive duty (frequency) of the fan 511a, for example, as illustrated in FIG. 9 (S8).

[0064] After that, the temperature-controlled liquid temperature controller 801 determines whether or not the inflow temperature T1 at the inlet of the radiator 511 has reached the predetermined temperature (threshold temperature) of, for example, 23°C, or higher (T1≥23°C) in S9. The operation in S8 and S9 is repeated until the inflow temperature T1 reaches the threshold temperature (23°C).

[0065] In response to a detection result that the inflow temperature T1 is equal to or higher than 23°C (T1≥23°C), the apparatus enters standby for printing.

[0066] Thus, based on the predetermined temperature (threshold temperature) of the temperature-controlled liquid and the detection results of the ambient temperature T5 of the radiator 511 and the inflow temperature T1 of the temperature-controlled liquid 510 at the inlet of the radiator 511, the rotation of the fan 511a of the radiator 511 is controlled. Accordingly, the temperature of the temperature-controlled liquid can be controlled with good responsiveness. This enables efficient cooling.

[0067] The target temperature (i.e., the predetermined temperature or threshold temperature) of the temperature-controlled liquid 510 is not limited to the above-mentioned 23°C.

[0068] Next, a second embodiment of the present disclosure is described with reference to FIG. 10. FIG. 10 is a schematic diagram of a temperature-controlled liquid circulation system according to the second embodiment.

[0069] The temperature-controlled liquid circulation system according to the present embodiment includes a plurality of temperature-controlled liquid supply manifolds 505 (505A to 505D) and a plurality of temperature-controlled liquid collection manifolds 506 (506A to 506D) corresponding to a plurality of head units 300 (300A to 300D). Each of the head unit 300 includes a plurality of heads 100 according to the first embodiment.

[0070] The temperature-controlled liquid circulation system includes the temperature-controlled liquid tank 501 as a common tank. From the common temperature-controlled liquid tank 501, the temperature-controlled liquid 510 is supplied to the temperature-controlled liquid supply manifolds 505 (505A to 505D), respectively, through circulation passages 500 (500A to 500D) via the liquid feed pumps 502 (502A to 502D) and radiators 511 (511A to 511D).

[0071] By contrast, after passing through the head units 300A to 300D and is collected by the temperature-controlled liquid collection manifolds 506 (506A to 506D), the flows of the temperature-controlled liquid 510 from the temperature-controlled liquid collection manifolds 506A and 506B are merged, and those from the temperature-controlled liquid collection manifolds 506C and 506D are merged. The temperature-controlled liquid 510 is then returned through two separate passages to the temperature-controlled liquid tank 501.

[0072] Thus, the circulation passage 500A starts from the temperature-controlled liquid tank 501, passes through the liquid feed pump 502A, the radiator 511A, the temperature-controlled liquid supply manifold 505A, the head unit 300A, and the temperature-controlled liquid collection manifold 506A, and then returns to the temperature-controlled liquid tank 501.

[0073] Similarly, the circulation passage 500B starts from the temperature-controlled liquid tank 501, passes through the liquid feed pump 502B, the radiator 511B, the temperature-controlled liquid supply manifold 505B, the head units 300B, and the temperature-controlled liquid collection manifold 506B, and then returns to the temperature-controlled liquid tank 501.

[0074] The circulation passage 500C starts from the temperature-controlled liquid tank 501, passes through the liquid feed pump 502C, the radiator 511C, the temperature-controlled liquid supply manifold 505C, the head unit 300C, and the temperature-controlled liquid collection manifold 506C, and then returns to the temperature-controlled liquid tank 501.

[0075] The circulation passage 500D starts from the temperature-controlled liquid tank 501, passes through the liquid feed pump 502D, the radiator 511D, the temperature-controlled liquid supply manifold 505D, the head unit 300D, and the temperature-controlled liquid collection manifold 506D, and then returns to the temperature-controlled liquid tank 501.

[0076] As described above, in the present embodiment, the respective radiators 511 for the head units 300 are connected in parallel.

[0077] With this structure, the cooling of the temperature-controlled liquid 510 by the radiator 511 can be controlled based on the target temperature of the temperature-controlled liquid 510 set in accordance with the viscosity of the liquid discharged by each head unit 300. For example, the temperature-controlled liquid temperature controller 801 receives viscosity information of the liquid, refers to association information between the viscosity of the liquid and the target temperature of the temperature-controlled liquid 510, and sets the target temperature of the temperature adjustment liquid 510.

[0078] For example, inks such as white ink containing titanium oxide as a colorant and clear ink (transparent ink) to form a transparent layer as the surface layer may be formulated to have a relatively high viscosity in order to prevent sedimentation and permeation. In this case, the temperature of the ink and the discharge temperature of the head are raised in accordance with the properties of the head.

[0079] Therefore, for example, the rotation speed of the fan 511a of the corresponding one of the radiators 511 connected in parallel is changed to adjust the temperature of the temperature-controlled liquid 510 at the outlet of the radiator 511, to adjust the temperature of the head 100 and that of the ink in association with the viscosity of the liquid to be discharged.

[0080] For example, regarding the inks of black (K), cyan (C), magenta (M), and yellow (Y) having a viscosity of 6 mPa·s at an ambient temperature of 23°C, the temperatures thereof are controlled with the temperature-controlled liquid of 23°C. By contrast, regarding clear ink and white ink having a viscosity of 6 mPa·s at an ambient temperature of 27°C, the temperatures thereof are controlled with the temperature-controlled liquid of 27°C.

[0081] In this way, the temperature of the temperature-controlled liquid can be changed individually for inks having different viscosity properties at the ordinary temperature, and stable discharge properties can be obtained.

[0082] In the present embodiment, the four radiators 511 connected in parallel are used. Alternatively, the cooling means for each head unit can be constructed of a plurality of radiators connected in series, in parallel connection, or in a combination of series connection and parallel connection.

[0083] Next, a third embodiment of the present disclosure is described with reference to FIG. 11. FIG. 11 is a schematic diagram of a temperature-controlled liquid circulation system according to the third embodiment of the present disclosure.

[0084] The temperature-controlled liquid circulation system according to the present embodiment includes the plurality of temperature-controlled liquid supply manifolds 505 (505A to 505D) and the plurality of temperature-controlled liquid collection manifolds 506 (506A to 506D) corresponding to the plurality of head units 300 (300A to 300D). Each of the head unit 300 includes the plurality of heads 100 according to the first embodiment.

[0085] The temperature-controlled liquid circulation system includes the common temperature-controlled liquid tank 501. From the common temperature-controlled liquid tank 501, the temperature-controlled liquid 510 is supplied to the temperature-controlled liquid supply manifolds 505A and 505B through a branched circulation passage 500A via a liquid feed pump 502A and radiators 511A(511A1 and 511A2) in serial connection.

[0086] Further, from the common temperature-controlled liquid tank 501, the temperature-controlled liquid 510 is supplied to the temperature-controlled liquid supply manifolds 505C and 505D through a branched circulation passage 500B via a liquid feed pump 502B and radiators 511B (511B1 and 511B2) in serial connection.

[0087] By contrast, the temperature-controlled liquid 510 that has passed through the each of the head units 300A to 300D is collected by the corresponding one of the temperature-controlled liquid collection manifolds 506 (506A to 506D), and then merged and returned to the temperature-controlled liquid tank 501.

[0088] Thus, the circulation passage 500A starts from the temperature-controlled liquid tank 501, passes through the liquid feed pump 502A, the radiators 511A1 and 511A2, the temperature-controlled liquid supply manifolds 505A and 505B, the head units 300A and 300B, and the temperature-controlled liquid collection manifolds 506A and 506B, and then returns to the temperature-controlled liquid tank 501.

[0089] Similarly, the circulation passage 500B starts from the temperature-controlled liquid tank 501, passes through the liquid feed pump 502B, the radiators 511B1 and 511B2, the temperature-controlled liquid supply manifolds 505C and 505D, the head units 300C and 300D, and the temperature-controlled liquid collection manifolds 506C and 506D, and then returns to the temperature-controlled liquid tank 501.

[0090] Further, each temperature-controlled liquid collection manifold 506 is thermally coupled to the head drive board 160 to cool the power amplification unit, such as a metal-oxide semiconductor field-effect transistor (MOSFET), which is mounted on the head drive board 160 and amplifies the drive waveform.

[0091] In the present embodiment, Q represents the total amount of heat generated by the plurality of heads 100 and the plurality of head drive boards 160 (head drive units) to drive the heads 100. That is, Q represents the total amount of heat generated by the cooling targets thermally coupled to the circulation passage 500. Further, α represents a limit coefficient that defines the upper limit of the amount of liquid (ink) applied to the sheet P (a liquid application target), T1 represents the inflow temperature of the temperature-controlled liquid 510 into the cooling means, T5 represents the airflow temperature (ambient temperature) of the cooling means, and Rr represents the thermal resistance of the cooling means.

[0092] At this time, the above-described temperature-controlled liquid circulation system is configured to satisfy a relationship expressed as:

[0093] That is, since flows of the temperature-controlled liquid 510 for cooling the four head units 300 (in addition, the head drive boards 160 as the head drive units) are merged into the single temperature-controlled liquid tank 501 on the circulation passage 500, the temperature rise of the temperature-controlled liquid 510 in the temperature-controlled liquid tank 501 is equivalent to the amount of heat generation corresponding to the upper limit of the amount of ink applied to the sheet P.

[0094] For example, in an apparatus that includes the four head units 300 to discharge the liquids of four colors, K, C, M, and Y, and each head unit 300 includes 11 heads 100, the total amount of heat generated by the respective heads 100 and the respective head drive boards 160 of the head units 300 is about 12 Kw. In a case where the sheet P is coated paper, when drawing is performed with a droplet size of 2 pl and a resolution of 1200 dpi, the ink limit coefficient is 1/2. Therefore, when the flows of the temperature-controlled liquid 510 are converged into the single temperature-controlled liquid tank 501 on the circulation passage 500 (a common tank is used) and cooled, the size of the cooling means can be about the half of that in the case where four temperature-controlled liquid tanks are provided.

[0095] Further, in the present embodiment, the heat generation amount of the heads 100 of the head unit 300 and the head drive board 160 is 6 Kw even when the upper limit of the amount of ink is taken into consideration. Therefore, the cooling means is constructed of the radiators 511 in a mixed connection in which one pair of serially connected radiators 511A1 and 511A2 is connected in parallel with another pair of serially connected radiators 511B1 and 511B2.

[0096] The relationship between a heat generation amount Q1 and the maximum cooling capacity in a case where the two radiators 511 are serially connected is expressed as:

[0097] where T11 represents the temperature (outflow temperature) of the temperature-controlled liquid 510 at the outlet of the first-stage radiator 511A1 or 511B1 of the serially connected radiator pair.

[0098] Since the two serially connected radiator pairs are connected in parallel, the relationship between the heat generation amount Q and the maximum cooling capacity is expressed as:

where T11 represents the temperature (outflow temperature) of the temperature-controlled liquid 510 at the outlet of the first-stage radiator 511A1 or 511B1 of the serially connected radiator pair.

[0099] In the present embodiment, the four radiators 511 are used as the cooling means, and the two pairs of serially connected radiators 511 are connected in parallel into a mixed connection. However, alternatively, the four radiators 511 can be connected in parallel as in the second embodiment. The cooling means can be constructed of a plurality of radiators connected in series, in parallel connection, or in a combination of serial connection and parallel connection.

[0100] Next, a fourth embodiment of the present disclosure is described with reference to FIG. 12. FIG. 12 is a block diagram illustrating a liquid (ink) supply system and a temperature-controlled liquid circulation system according to the fourth embodiment.

[0101] The temperature-controlled liquid circulation system of the present embodiment includes a heat exchanger 503 that exchanges heat with the temperature-controlled liquid 510. The heat exchanger 503 includes the radiator 511 that cools the temperature-controlled liquid 510 and a heater 512 that heats the temperature-controlled liquid 510.

[0102] As the liquid feed pump 502 is driven, the temperature-controlled liquid 510 stored in the temperature-controlled liquid tank 501 circulates through the circulation passage 500 that passes the liquid feed pump 502, the heat exchanger 503, the temperature-controlled liquid supply manifold 505, the head 100, and the temperature-controlled liquid collection manifold 506, and then returns to the temperature-controlled liquid tank 501.

[0103] In the present embodiment, the ink supply manifold 402 and the temperature-controlled liquid supply manifold 505 are thermally coupled.

[0104] As a result, the temperature of the ink can be adjusted to the required temperature before the ink is supplied to each head 100, and ink discharge can be stable.

[0105] The rotation of the fan 511a of the radiator 511 can be controlled in the same manner as in the first embodiment.

[0106] Next, a description is given of the connections of the temperature-controlled liquid supply manifold and the temperature-controlled liquid collection manifold with the heads, with reference to FIG. 13. FIG. 13 is a schematic diagram illustrating the connections thereof.

[0107] The temperature-controlled liquid supply manifold 505 includes a plurality of outlet ports 556 from which the temperature-controlled liquid 510 is supplied to the heads 100. The extreme upstream outlet port 556 (FIG. 17) in the flow in a temperature-controlled liquid channel 551 of the temperature-controlled liquid supply manifold 505 is coupled, via the head 100, to extreme upstream one of inlet ports of a liquid channel 561 of the temperature-controlled liquid collection manifold 506. Similarly, the second outlet port 556 from the upstream side of the temperature-controlled liquid channel 551 is coupled, via the head 100, to the second inlet port, from the upstream side of the liquid channel 561, of the temperature-controlled liquid collection manifold 506. The subsequent connections are similar thereto. The extreme downstream outlet port 556 of the temperature-controlled liquid channel 551 is coupled, via the head 100, to the extreme downstream inlet port of the liquid channel 561 of the temperature-controlled liquid collection manifold 506.

[0108] Such connection relationships can equalize the configurations of the liquid channels of the temperature-controlled liquid 510 that pass through all the heads 100, thereby equalizing the pressure loss in the liquid channels of the temperature-controlled liquid 510 passing through the heads 100. Accordingly, the flow rates and flow speeds are equalized, and the temperature can be equally adjusted in all the heads 100.

[0109] In this case, the temperature-controlled liquid collection manifold 506 is preferably made of the same material and has the same length as the temperature-controlled liquid supply manifold 505. For example, an extruded aluminum alloy such as A6063 can be used to produce the temperature-controlled liquid supply manifold 505 and the temperature-controlled liquid collection manifold 506 by extrusion molding. Then, the manufacturing cost can be low.

[0110] Next, a fifth embodiment of the present disclosure is described with reference to FIG. 14. FIG. 14 is a view illustrating a configuration of a head unit and a circulation passage of the temperature-controlled liquid according to the fifth embodiment.

[0111] The head unit 300 includes pairs of heads 100 (dual heads) to discharge liquid, arranged in a staggered arrangement.

[0112] The temperature-controlled liquid 510 is supplied from the temperature-controlled liquid supply manifold 505 to the temperature-controlled liquid supply port 132 of the first one of the pair of heads 100. Then, the temperature-controlled liquid 510 passes through the frame 120 of the first head 100 and is collected from the temperature-controlled liquid collection port 133. The temperature-controlled liquid 510 collected from the first head 100 is supplied to the temperature-controlled liquid supply port 132 of the second head 100. Then, the temperature-controlled liquid 510 passes through the frame 120 of the second head 100 and is collected from the temperature-controlled liquid collection port 133. The head pairs can be a combination of heads 100 in a staggered arrangement. Further, the pairs of heads 100 can be arranged in multiple rows for high density recording.

[0113] The temperature-controlled liquid 510 collected from the temperature-controlled liquid collection port 133 of the second head 100 is collected in the temperature-controlled liquid collection manifold 506.

[0114] Next, a description is given of an example of the ink supply manifold, the temperature-controlled liquid supply manifold, and the thermal coupling therebetween, with reference to FIGS. 15 to 17. FIG. 15 is an exterior perspective view of an example of the ink supply manifold. FIG. 16 is an exterior perspective view of the temperature-controlled liquid supply manifold. FIG. 17 is a cross-sectional view of the temperature-controlled liquid supply manifold illustrated in FIG. 16. FIG. 18 is a perspective view illustrating the ink supply manifold and the temperature-controlled liquid supply manifold in an assembled state.

[0115] The ink supply manifold 402 is a tubular member in which an ink supply channel 420 that is a liquid supply channel is formed. The ink supply manifold 402 includes an inlet port 421 to which ink is supplied from the ink tank 401 and outlet ports 422 from which the ink is supplied to the heads 100.

[0116] The temperature-controlled liquid supply manifold 505 is a plate member in which the temperature-controlled liquid channel 551 of the temperature-controlled liquid 510 is formed. The temperature-controlled liquid supply manifold 505 includes an inlet port 555 to which temperature-controlled liquid 510 is supplied from the heat exchanger 503 and the outlet ports 556 from which the temperature-controlled liquid 510 is supplied to the heads 100, respectively. The temperature-controlled liquid supply manifold 505 includes a manifold body 552 in which a plurality of liquid channels 551a to 551d extends along the longitudinal direction thereof. Further, folding-back caps 553 are attached to both ends of the manifold body 552.

[0117] With this structure, the plurality of liquid channels 551a to 551d is connected and folded back in the channels of the folding-back caps 553, thereby forming the temperature-controlled liquid channel 551. Since the temperature-controlled liquid channel 551 includes the liquid channels 551a to 551d that are folded back, the temperature gradient of the temperature-controlled liquid 510 inside the temperature-controlled liquid supply manifold 505 can be reduced.

[0118] The liquid channel 551d is provided with the outlet ports 556 to supply the temperature-controlled liquid 510 to the heads 100, respectively. The temperature-controlled liquid 510 is supplied from the outlet port 556 to the temperature-controlled liquid supply port 132 of the head 100 via the supply passage 513.

[0119] A side face of the manifold body 552 of the temperature-controlled liquid supply manifold 505 includes fitting portions 558 for fitting with the ink supply manifold 402. Two fitting portions 558 extend along the longitudinal direction of the manifold body 552.

[0120] As illustrated in FIG. 18, two ink supply manifolds 402 are respectively fitted to the fitting portions 558 of the manifold body 552 of the temperature-controlled liquid supply manifold 505, and thus the temperature-controlled liquid supply manifold 505 and the ink supply manifolds 402 are thermally coupled together. From the upper ink supply manifold 402, the ink is supplied through the outlet ports 422 to the heads 100 on the upstream side in the conveyance direction illustrated in FIG. 2. From the lower ink supply manifold 402, ink is supplied through the outlet ports 422 to the heads 100 on the downstream side in the conveyance direction illustrated in FIG. 2.

[0121] Thus, by thermally coupling the temperature-controlled liquid supply manifold 505 and the ink supply manifolds 402, the ink supply channel 420, which is the liquid supply channel, and the circulation passage 500 are thermally connected.

[0122] Accordingly, the ink temperature can be adjusted before the ink is supplied to the plurality of heads 100, thereby reducing temperature changes (temperature gradient) of the ink supplied to the heads 100. This reduces variations in the ink discharge properties of the heads 100.

[0123] Next, a description is given of a sixth embodiment of the present disclosure, with reference to FIGS. 19 and 20. FIG. 19 is a perspective view of a manifold according to the sixth embodiment, and FIG. 20 is a cross-sectional view of the manifold.

[0124] In the present embodiment, the temperature-controlled liquid supply manifold 505 and the ink supply manifold 402 described in the above embodiments are integral in a manifold 600. In other words, the manifold 600 is a member that distributes and supplies the liquid (ink) and the temperature-controlled liquid 510 to the plurality of heads 100.

[0125] In a body of the manifold 600, the temperature-controlled liquid channels 551 through which the temperature-controlled liquid 510 flows and the ink supply channel 420 through which ink flows are formed. The temperature-controlled liquid channel 551 is coupled to the temperature-controlled liquid supply port 132 of each head 100 by the supply passage 513 such as a tube. The ink supply channel 420 is coupled to each head 100 through the outlet port 422.

[0126] As illustrated in FIG. 20, the ink supply channel 420 is preferably disposed between the two of the liquid channels 551a to 551d through which the temperature-controlled liquid 510 flows.

[0127] Also in the present embodiment, the temperature-controlled liquid channels 551 and the ink supply channel 420 are thermally coupled. Accordingly, the ink temperature can be adjusted before the ink is supplied to the plurality of heads 100, thereby reducing temperature changes (temperature gradient) of the ink supplied to the heads 100. This reduces variations in the ink discharge properties of the heads 100.

[0128] The manifold 600 in which the temperature-controlled liquid supply manifold 505 and the ink supply manifold 402 are integral as in the present embodiment can be easily modeled by, for example, a three-dimensional (3D) fabricating apparatus (i.e., a 3D printer).

[0129] Next, a description is given of the temperature-controlled liquid collection manifold 506 and an example of the thermal coupling of the temperature-controlled liquid collection manifold 506 with the head drive board 160, with reference to FIGS. 21 to 23. FIG. 21 is a front cross-sectional view, referring to which the temperature-controlled liquid channel of the temperature-controlled liquid collection manifold 506 is described in detail. FIG. 22 is a perspective view illustrating the connection between the temperature-controlled liquid collection manifold 506 and the head drive board 160. FIG. 23 is an exploded perspective view thereof.

[0130] The temperature-controlled liquid collection manifold 506 has therein the liquid channel 561 through which the temperature-controlled liquid 510 supplied via the collection passage 514 from each head 100 flows. Arrow A indicates the direction of flow of the temperature-controlled liquid 510. As illustrated in FIG. 21, the temperature-controlled liquid collection manifold 506 further includes inlet ports 565 coupled to the plurality of collection passages 514 and the outlet port 566 to discharge the temperature-controlled liquid 510 to the temperature-controlled liquid tank 501.

[0131] The liquid channel 561 is constructed of a plurality of channels extending along the longitudinal direction and includes turnups at both ends, so that the plurality of channels are connected.

[0132] On the head drive board 160, a power amplification unit 161 that amplifies a drive waveform is mounted, and a heatsink 162 is provided in contact with the power amplification unit 161. The power amplification unit 161 is constructed of, for example, a MOSFET.

[0133] In this structure, the heatsink 162 of the head drive board 160 is secured to the temperature-controlled liquid collection manifold 506 via a heat conductive sheet 163, thereby thermally coupling the temperature-controlled liquid collection manifold 506 and the power amplification unit 161 of the head drive board 160.

[0134] Next, a description is given of the positional relationship among the heads 100, the temperature-controlled liquid supply manifold 505, and the temperature-controlled liquid collection manifold 506, with reference to FIG. 24. FIG. 24 is a view illustrating the positional relationship therebetween.

[0135] The temperature-controlled liquid collection manifold 506 and the temperature-controlled liquid supply manifold 505 are disposed above the heads 100.

[0136] With this configuration, high image quality can be obtained without reducing the nozzle density (head arrangement density) of the heads 100. Further, the distance between the ink supply passage 403 and the supply passage 513 of the temperature-controlled liquid can be made short, and the temperature changes in each supply passage can be restricted.

[0137] Further, the frame 120 of the head 100 having a smaller heat generation amount than that of the head drive board 160 is disposed lower than the head drive board 160, and the frame 120 of the head 100 and the head drive board 160 are thermally coupled to the circulation passage 500 in this order. The head drive board 160 thermally coupled to the temperature-controlled liquid collection manifold 506 is disposed higher than the heads 100.

[0138] As a result, the heat generation portions are cooled with the temperature-controlled liquid in the ascending order of the amount of heat generation, and, the temperature rise of the head 100 can be inhibited.

[0139] The head unit 300, the temperature-controlled liquid collection manifold 506, and the temperature-controlled liquid supply manifold 505 are combined by a cover 1000. Therefore, maintainability is improved.

[0140] Next, a seventh embodiment of the present disclosure is described with reference to FIG. 25. FIG. 25 is a plan view of a printer as a liquid discharge apparatus according to the seventh embodiment of the present disclosure.

[0141] The printer 1 is a serial type printer. The printer 1 includes a guide 1001 bridged between a left side plate 1010A and a right side plate 1010B, and a carriage 1003 held by the guide 1001 to be able to reciprocate in a main scanning direction indicated by arrow MSD (hereinafter "main scanning direction MSD"). The carriage 1003 reciprocates in the main scanning direction MSD driven by a main-scanning motor 1005 via a timing belt 1008 bridged between a driving pulley 1006 and a driven pulley 1007.

[0142] Four liquid discharge units 1004 are mounted on the carriage 1003. In each of the liquid discharge units 1004, the head 100 (liquid discharge heads) is integral with a sub tank 1035.

[0143] The sub tanks 1035 include ink reservoirs to store respective color liquids supplied to the heads 100.

[0144] Th body of the printer 1 includes a cartridge holder 1051 in which main tanks 1050 (1050a to 1050f) are replaceably mounted. The main tanks 1050 contain the respective color liquids. The cartridge holder 1051 includes a liquid feed pump 1052 to feed the respective color inks from the main tanks 1050 to the sub tanks 1035 via supply tubes 1056 (also referred to as liquid supply passages) of respective colors.

[0145] To convey a sheet P, the printer 1 includes a conveyor belt 1012 as a conveyor to attract the sheet P and convey the sheet P at a position opposite the heads 100. The conveyor belt 1012 is an endless belt stretched between a conveyance roller 1013 and a tension roller 1014. The sheet P is attracted to the conveyor belt 1012 by electrostatic attraction or air suction.

[0146] The conveyor belt 1012 rotates in a sub-scanning direction indicated by arrow (hereinafter "sub-scanning direction belt SSD") as the conveyance roller 1013 is driven by a sub-scanning motor 1016 via a timing belt 1017 and a timing pulley 1018.

[0147] On one side in the main scanning direction MSD in which the carriage 1003 moves, a head maintenance device 1020 is disposed on a side of the conveyor belt 1012. The head maintenance device 1020 is a maintenance mechanism to maintain and recover the heads 100.

[0148] The head maintenance device 1020 includes, for example, a suction cap 1021, three moisturizing caps 1022, and a wiper 1023. The suction cap 1021 also serves as a moisturizing cap to cover the nozzle face (on which the nozzles 104 are formed) of the head 100. The wiper 1023 wipes the nozzle face.

[0149] An encoder scale 1123 provided with a predetermined pattern extends between the right and left side plates 1010A and 1010B, along the main scanning direction MSD in which the carriage 1003 moves. On the carriage 1003, an encoder sensor 1124 constructed of a transmissive photosensor is mounted, to read the pattern of the encoder scale 1123. The encoder scale 1123 and the encoder sensor 1124 together construct a linear encoder 1122 (a main scanning encoder) which detects the movement of the carriage 1003.

[0150] The printer 1 further includes a code wheel 1125 attached to a shaft of the conveyance roller 1013, and an encoder sensor 1126 to detect a pattern formed on the code wheel 1125. The encoder sensor 1126 can be a transmissive photosensor. The code wheel 1125 and the encoder sensor 1126 construct a rotary encoder (a sub-scanning encoder) that detects the amount of movement and the position of the conveyor belt 1012.

[0151] In the printer 1 thus configured, the sheet P is fed and attracted onto the conveyor belt 1012. As the conveyor belt 1012 rotates, the sheet P attracted thereon is conveyed in the sub-scanning direction SSD.

[0152] While the carriage 1003 moves in the main scanning direction MSD, the heads 100 are driven according to image signals to discharge the liquid onto the sheet P kept stationary, thus recording one line of an image. Then, after the sheet P is fed by a predetermined distance, another line of the image is recorded.

[0153] In response to a receipt of a recording end signal or a signal indicating that a trailing end of the sheet P has reached a recording area, the printer 1 ends the print operation and ejects the sheet P to an output tray.

[0154] The configurations relating to the circulation of the temperature-controlled liquid, the rotation control of the fan of the radiator, and the control of the heating waveform applied to the head drive board described in the above embodiments are applicable also to the serial type liquid discharge apparatus according to the present embodiment.

[0155] In the present disclosure, the liquid to be discharged is not limited to a particular liquid as long as the liquid has a viscosity or surface tension to be discharged from a head (a liquid discharge head). However, preferably, the viscosity of the liquid is not greater than 30 mPa·s under ordinary temperature and ordinary pressure or by heating or cooling. Examples of the liquid include a solution, a suspension, or an emulsion including, for example, a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, a resin, a surfactant, a biocompatible material, such as deoxyribonucleic acid (DNA), amino acid, protein, or calcium, and an edible material, such as a natural colorant. Such a solution, a suspension, or an emulsion can be used for, e.g., inkjet ink; surface treatment liquid; a liquid for forming an electronic element component, a light-emitting element component, or an electronic circuit resist pattern; or a material solution for three-dimensional fabrication.

[0156] The term "head" signifies liquid discharge heads employing, as an energy source to generate energy to discharge liquid, a piezoelectric actuator (a laminated piezoelectric element or a thin-film piezoelectric element), a thermal actuator that employs an electrothermal transducer element, such as a heat element, or an electrostatic actuator including a diaphragm and opposed electrodes.

[0157] Examples of the liquid discharge apparatus include, not only apparatuses capable of discharging liquid to materials to which liquid can adhere, but also apparatuses to discharge a liquid toward gas or into a liquid.

[0158] The liquid discharge apparatus can include at least one of devices for feeding, conveying, and ejecting a material to which liquid can adhere. The liquid discharge apparatus can further include at least one of a pretreatment apparatus and a post-treatment apparatus.

[0159] The "liquid discharge apparatus" can be, for example, an image forming apparatus to form an image on a sheet by discharging ink, or a three-dimensional fabricating apparatus to discharge a fabrication liquid to powder layers in which a powder material is piled in layers, to form a three-dimensional fabricated object.

[0160] The "liquid discharge apparatus" is not limited to an apparatus to discharge liquid to visualize meaningful images, such as letters or figures. For example, the liquid discharge apparatus can be an apparatus to form meaningless patterns, or an apparatus to fabricate three-dimensional images.

[0161] The above-mentioned term "material to which liquid can adhere" represents a material which allow liquid can, at least temporarily, adhere thereto and solidify thereon, or a material into which liquid permeates. Examples of the "material to which liquid can adhere" include recording media, such as paper, recording paper, recording sheets, film, and cloth; electronic components, such as electronic substrate and a piezoelectric element; and media, such as a powder layer, an organ model, and a testing cell. The "material to which liquid can adhere" includes any material to which liquid adheres, unless otherwise specified.

[0162] The above-mentioned "material to which liquid adheres" can be any material, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, or the like, as long as liquid can temporarily adhere.

[0163] The "liquid discharge apparatus" can be an apparatus to relatively move the liquid discharge head and a material onto which liquid can adhere. However, the liquid discharge apparatus is not limited to such an apparatus. For example, the liquid discharge apparatus can be a serial head apparatus that moves the liquid discharge head or a line head apparatus that does not move the head.

[0164] Examples of the "liquid discharge apparatus" further include a treatment liquid coating apparatus to discharge a treatment liquid to a sheet to coat the sheet surface with the treatment liquid, thereby reforming the sheet surface. Another example is an injection granulation apparatus to discharge, through nozzles, a composition liquid including raw materials dispersed in a solution, thereby granulating fine particles of the raw materials.

[0165] The terms "image formation," "recording," "printing," "image printing," and "fabricating" used herein can be used synonymously with each other.

Claims

1. A liquid discharge apparatus (1) comprising:

a head (100) configured to discharge a liquid;

a circulation passage (500) coupled to the head (100), the circulation passage (500) through which a temperature-controlled liquid circulates;

a radiator (511) including a fan (511a) and configured to cool the temperature-controlled liquid;

a head drive board (160) mounted with a power amplification unit (161) configured to amplify a drive waveform applied to the head (100);

an ambient temperature sensor (811) configured to detect an ambient temperature of the radiator (511);

a liquid temperature sensor (812) configured to detect a temperature of the temperature-controlled liquid at an inlet of the radiator (511); and

a controller (801) configured to control at least one of a rotation of the fan (511a) of the radiator (511) and a heating waveform applied to the head drive board (160), based on a target temperature of the temperature-controlled liquid, a detected ambient temperature of the radiator (511), and a detected temperature of the temperature-controlled liquid at the inlet of the radiator (511).

2. The liquid discharge apparatus (1) according to claim 1, wherein the controller (801) is configured to control both the rotation of the fan (511a) of the radiator (511) and the heating waveform applied to the head drive board (160).

3. The liquid discharge apparatus (1) according to any one of claim 1 or 2, further comprising a liquid supply passage (402,403) through which the liquid is supplied to the head (100),
wherein the liquid supply passage (402,403) is thermally coupled with the circulation passage (500).

4. The liquid discharge apparatus (1) according to any one of claims 1 to 3,
wherein the circulation passage (500) and the head drive board (160) are thermally coupled with each other.

5. The liquid discharge apparatus (1) according to any one of claims 1 to 4, further comprising:

a plurality of heads (100) including the head (100), the plurality of heads (100) configured to discharge the liquid;

a temperature-controlled liquid supply manifold (505) configured to distribute the temperature-controlled liquid to the plurality of heads (100); and

a temperature-controlled liquid collection manifold (506) configured to collect the temperature-controlled liquid from the plurality of heads (100).

6. The liquid discharge apparatus (1) according to claim 5, further comprising a liquid supply manifold (402) configured to distribute the liquid to the plurality heads (100),
wherein the liquid supply manifold (402), the temperature-controlled liquid supply manifold (505), and the temperature-controlled liquid collection manifold (506) are disposed higher than the plurality of heads (100).

7. The liquid discharge apparatus (1) according to claim 5 or 6,
wherein the circulation passage (500) is configured to circulate the temperature-controlled liquid in an order of the temperature-controlled liquid supply manifold (505), one of the plurality of heads (100), another of the plurality of heads (100), and the temperature-controlled liquid collection manifold (506).

8. The liquid discharge apparatus (1) according to any one of claims 1 to 4, further comprising:

a plurality of heads (100) including the head (100), the plurality of heads (100) configured to discharge different liquids; and

a single temperature-controlled liquid tank (501) configured to store the temperature-controlled liquid and coupled to the circulation passage (500),

wherein the circulation passage (500) is configured to cause the temperature-controlled liquid to flow from the single temperature-controlled liquid tank (501) via the radiator (511) to the plurality of heads (100).

9. The liquid discharge apparatus (1) according to any one of claims 1 to 4, further comprising:

a plurality of heads (100) including the head (100), the plurality of heads (100) configured to discharge different liquids; and

a plurality of radiators (511) including the radiator (511),

wherein the plurality of radiators (511) is connected in parallel to each other on the circulation passage (500) and coupled to the plurality of heads (100), respectively,

wherein the target temperature of the temperature-controlled liquid is set in association with a viscosity of each of the different liquids, and

wherein the controller (801) is configured to control the rotation of the fan (511a) of each of the plurality of radiators (511) according to the target temperature associated with the viscosity of the liquid discharged by corresponding one of the plurality of heads (100).

Drawing