Inkjet printer and printing method by the inkjet printer

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to an inkjet printer and a printing method by the inkjet printer, and more particularly to an inkjet printer by which color printing is made on a medium to be a printing object with the use of printing inks having a plurality of colors in accordance with an inkjet process and a printing method by the inkjet printer.

[0002] The term "medium" used herein includes a variety of materials such as resin materials, e.g. PVC, polyester, thermoplastic resin, thermosetting resin and the like; metallic materials, e.g. aluminum, iron, copper and the like; ferrous medium, e.g. medium with magnetic powder, medium with a magnetic plate and the like; glass materials; wood or the like materials in addition to a variety of recording papers including papers such as a plain paper as a matter of course.

[0003] Moreover, it should be noted that the term "inkjet system" used herein means printing processes by means of various manners in accordance with a heretofore well-known inkjet technology including a variety of continuous inkjet processes such as a binary deflection inkjet process, and a continuous deflection inkjet process; and a variety of drop-on-demand inkjet processes such as a thermal inkjet process, and a piezoelectric inkjet process.

2. Description of Background Art

[0004] Heretofore, there has been such a known inkjet printer the whole operations thereof are controlled by a microcomputer wherein predetermined printing operations are conducted by jetting printing inks on a recording paper, which is fed from a feeder and then transferred, from an ink head transferring along the width direction of the recording paper (in the present specification, a traveling direction of a medium such as a recording paper is optionally referred to as "vertical scanning direction", the direction perpendicular to the vertical scanning direction is optionally referred to as "width direction", and the width direction of the medium is optionally referred to as "horizontal scanning direction") in accordance with an inkjet printing process.

[0005] Furthermore, in general, such an inkjet printer as described above is constructed in such that plural color inks can be jetted on a recording paper from ink heads, whereby a color printing can be realized with respect to the recording paper.

[0006] As described above, liquid inks are jetted on a medium such as a recording paper from ink heads of an inkjet printer, and droplets of the inks adhere on the medium by the application of an inkjet printer. In this respect, however, in the case where a color printing is conducted with respect to a medium such as a resin material, or a metallic material which does not absorb an ink in a liquid state or a recording paper and the like the surface of which is processed so that the surface absorbs hardly a liquid, the ink jetted on the medium is not sufficiently absorbed by the medium. As a result, there is a possibility of such problem that the inks jetted being different in their colors from one another and adjacent to each other do not dry rapidly on the medium, so that they are mixed with each other in the boundary surfaces thereof.

[0007] From US 2006/0274095 A 1 and EP 1 902 848 A2 inkjet printers are known. EP 1 892 110 A2 shows a thermal printer with a special guide plate for guiding a recording paper, the guide plate being also useable for inkjet printers.

SUMMARY OF THE INVENTION

[0008] The present invention has been made in view of the above-described problems involved in the prior art, and an object of the invention is to provide an inkjet printer and a printing method by the inkjet printer which is arranged in such that even if an object medium on which color printing is to be conducted is a medium which absorbs no liquid ink or a medium which absorbs hardly a liquid ink, a color printing is completed without any color mixture in the boundary surface between adjacent inks on the object medium in the case where the color printing is conducted by the use of a plurality of different liquid color inks on the object medium.

[0009] That object is solved by an inkjet printer according to claim I and a printing method according to claim 5. Advantageous further embodiments are covered in the respective sub-claims.

[0010] In order to achieve the above-described object, the present invention is constituted in such that when a color printing is conducted by the use of a plurality of liquid inks having different colors from one another, a printing is made by one color ink selected from the plurality of color inks, and another different color ink is selected to carry out another printing operation after drying the former printed color ink, likewise a further printing is carried out individually in a sequential order with the color ink different from that which have been already printed and selected from the plurality of color inks.

[0011] More specifically, when a color printing is conducted by the use of a plurality of liquid inks having different colors from one another, one color ink is selected and jetted onto a medium in accordance with an inkjet process to conduct a printing while transferring the medium from a predetermined print starting position of the medium to a direction in the vertical scanning direction, when the printing by applying the one color ink to the medium is completed, a process in which the medium is transferred along another direction in the vertical scanning direction to return the medium to the print start position is conducted, and then, a process in which the ink having a different color from the one color ink is selected to jet onto the medium in accordance with the inkjet process thereby implementing the printing is repeated, whereby the color printing is accomplished by the use of the liquid inks having the plurality of different colors.

[0012] During a period of time required for completing a process from the transfer of the medium along another direction in the vertical scanning direction to the returning process of the medium to the predetermined print starting position, droplets of the one color ink jetted onto the medium are dried.

[0013] Thus, in accordance with the present invention, there is no color mixture in the boundary surface between the inks printed in even the case where a printing is conducted with respect to a medium which does not absorb or absorbs hardly a liquid ink, so that a high quality printing result can be obtained.

[0014] Namely, the present invention provides an inkjet printer jetting inks having a plurality of colors in response to image data onto a medium being the printing object according to an inkjet process, comprising a medium transfer means for transferring reciprocately the medium of the printing object along a predetermined direction; a plurality of ink heads each containing a different color ink and conducting a printing with respect to the medium by jetting the inks contained onto the medium in response to image data according to the inkjet process; and a control means for selecting any one of the plurality of ink heads to conduct a printing with respect to the medium while transferring the medium from a predetermined print starting position to a direction in the predetermined directions by controlling the medium transfer means, after completing the printing, controlling the medium transfer means to transfer the medium in another direction in the predetermined direction, thereby returning the medium to the printing start position and selecting any one of the plurality of ink heads different from the ink head that completed the printing to conduct another printing with respect to the medium.

[0015] In the inkjet printer according to the present invention, the control means may select any one of the plural ink heads in a predetermined order, and may implement a printing with respect to the medium by means of all the plural ink heads.

[0016] In the inkjet printer according to the present invention, the medium transfer means may include a grid roller rotated by driving a drive means and pinch rollers energized with respect to the grid roller; and may sandwich the medium between the grid roller and the pinch rollers, and may change movably the rotational direction of the grid roller to transfer reciprocately the medium along predetermined directions.

[0017] Furthermore, the present invention provides a printing method by the inkjet printer in which plural color inks are jetted onto a print object medium in response to image data according to an inkjet process thereby to conduct a printing comprising the steps of selecting any one of a plurality of ink heads to implement the printing with respect to the medium while controlling a medium transfer means transferring reciprocately the print object medium along predetermined directions to transfer the medium from a predetermined print start position to a direction of the predetermined directions, the plurality of ink heads containing different color inks, respectively, and jetting the inks contained onto the medium in response to image data according to the inkjet process, respectively, to conduct the printing; after completing the printing, controlling the medium transfer means to transfer the medium along another direction in the predetermined directions thereby returning the medium to the print starting position; and selecting any one of the plurality of ink heads different from the ink head which completed the printing to implement a printing with respect to the medium.

[0018] In the printing method by the inkjet printer according to the present invention, any one of the plurality of ink heads may be selected in a predetermined order, and a printing may be implemented with all the plurality of ink heads.

[0019] Since the present invention is constituted as described above, the invention exhibits such an excellent advantage that when a color printing is conducted with respect to a medium by using liquid inks having a plurality of different colors, there is no color mixture in the boundary surface between the inks adjacent to each other on the medium in even the case where an object on which a color printing is to be made is a medium which does not absorb a liquid ink or a medium which absorbs hardly a liquid ink.

[0020] Thus, the present invention can be used for a color printing. Especially, the present invention can be preferable used for a printing of a color printing sample of the inks installed in the inkjet printer on the medium.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a schematic constitutional perspective view showing an inkjet printer according to the present invention;

FIG. 2 is a conceptual constitutional explanatory view showing a supply route for an ink in the inkjet printer shown in FIG. 1;

FIG. 3 is a schematic constitutional partly sectional view taken along the line A-A of the inkjet printer shown in FIG. 1; and

FIG. 4 is a flowchart representing the processing steps of printing operations in the inkjet printer shown in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT

[0022] In the following, an example of the manner of practice of an inkjet printer and a printing method by the inkjet printer according to the present invention will be described in detail by referring to the accompanying drawings.

[0023] First, FIG. 1 is a schematic constitutional perspective view showing an inkjet printer according to the present invention; FIG. 2 is a conceptual constitutional explanatory view showing a supply route for an ink in the inkjet printer shown in FIG. 1; FIG. 3 is a schematic constitutional partly sectional view taken along the line A-A of the inkjet printer shown in FIG. 1; and FIG. 4 is a flowchart representing the processing steps of printing operations in the inkjet printer shown in FIG. 1.

[0024] In the inkjet printer 10 shown in FIGS. 1 through 3, a recording paper is used as the medium, and the recording paper is conveyed in the direction perpendicular to the horizontal scanning direction being the width direction of the recording paper, i.e. the vertical scanning direction being the longitudinal direction of the recording paper.

[0025] The inkjet printer is composed of a base member 14 being a fixation system which is supported by a pedestal 12 and disposed so as to extend in the horizontal scanning direction, side members 16L and 16R provided at the opposite ends of the base member 14 in the direction perpendicular to the base member 14, respectively, a central wall 18 for connecting the opposite side members 16L and 16R to each other, a wire 22 disposed in parallel to the wall surface of the central wall 18 and movable in the horizontal scanning direction, a holder 24 provided fixedly onto the wire 22 and mounted slidably on a guide rail 20, an ink head section 28 installed in the holder 24 so as to oppose to the recording paper 26 (although a detailed illustration thereof is omitted, the recording paper 26 is wound into a roll, and it is placed on the rear side of the pedestal 12 in the vertical scanning direction thereof) on the base member 14, a grid roller 30 for conveying the recording paper 26 in the vertical scanning direction thereof, a stepping motor 31 being a drive means for driving the grid roller 30, and a pinch roller 40 disposed on the upper side of the base member 14 and energized against the grid roller 30 by means of a spring (not shown) to pinch the recording paper 26 between the pinch roller 40 and the grid roller 30.

[0026] The whole operations of the inkjet printer 10 as described above are controlled by a microcomputer 100.

[0027] Moreover, the inkjet printer 10 stores previously image data for printing the color printing sample representing the colors of the inks accumulated in an ink tank section 32 (which will be described hereunder) in the memory of the microcomputer 100, and further is provided with an interface for inputting desired image data from the outside.

[0028] More specifically, the ink head section 28 provided in the holder 24 is composed of four ink heads 28a, 28b, 28c, and 28d for jetting liquid different color inks on a medium in accordance with an inkjet process, respectively.

[0029] Each of the four ink heads 28a, 28b, 28c, and 28d constituting the ink head section 28 has the same structure as that of the others; and they are sequentially disposed inside the holder 24 in the order of the ink head 28a, the ink head 28b, the ink head 28c, and the ink head 28d along the horizontal scanning direction from the left side to the right side.

[0030] These four ink heads 28a, 28b, 28c, and 28d are connected to subsidiary tanks 36 through ink tubes 34, respectively; and these subsidiary tanks 36 are connected to an ink tank section 32 composed of four ink tanks 32a, 32b, 32c, and 32d accumulating liquid different color inks through ink tubes 38, respectively and disposed in the side member 16R (see FIG. 2).

[0031] Although a detailed illustration is omitted, a plurality of inkjet nozzles are formed as jet openings for jetting inks on a surface 26a of the recording paper 26 on the bottom of each of the four heads 28a, 28b, 28c, and 28d constituting the ink head section 28 so as to oppose to the recording paper 26.

[0032] The ink tank section 32 will be described in detail herein. The ink tank section 32 is composed of the ink tank 32a connected to the ink head 28a through the ink tube 34, the subsidiary tank 36, and the ink tube 38; the ink tank 32b connected to the ink head 28b through the ink tube 34, the subsidiary tank 36, and the ink tube 38; the ink tank 32c connected to the ink head 28c through the ink tube 34, the subsidiary tank 36, and the ink tube 38; and the ink tank 32d connected to the ink head 28d through the ink tube 34, the subsidiary tank 36, and the ink tube 38.

[0033] These ink tanks 32a, 32b, 32c, and 32d are those containing liquid inks, respectively; and inks having different colors from one another are contained in the ink tanks 32a, 32b, 32c, and 32d, respectively.

[0034] Specifically, the ink tank 32a contains a blue (cyanic) ink, the ink tank 32b contains yellow ink, the ink tank 32c contains red (magenta) ink, and the ink tank 32d contains black ink.

[0035] These inks having different colors from one another and contained in the ink tanks 32a, 32b, 32c, and 32d, respectively are fed to the subsidiary tanks 36 through the ink tubes 38, respectively; the inks fed to the subsidiary tanks 36 are fed to the ink head section 28 through the ink tubes 34 provided in an ink tube guide (not shown); and the inks are jetted onto the surface 26a of the recording paper 26 from the inkjet nozzles (not shown), respectively.

[0036] Furthermore, the recording paper 26 is held between the pinch roller 40 and the grid roller 30; and when the grid roller 30 is rotated by driving the stepping motor 31, the recording paper is adapted to be conveyed in the front side or the rear side along the vertical scanning direction in accordance with the rotating direction of the grid roller 30, so that the recording paper is reciprocatably moved along the vertical scanning direction.

[0037] More specifically, a hole section 14a extending in the horizontal scanning direction is bored in the base member 14, and the grid roller 30 is placed in the hole section 14a so as to extend in the horizontal scanning direction.

[0038] A pair of right and left pinch rollers 40 is disposed so as to oppose to each other at the right and left end positions of the grid roller 30 in the horizontal scanning direction; and the pinch rollers 40 are energized against the grid roller 30 so as to abut thereon by means of a spring (not shown).

[0039] The recording paper 26 is sandwiched between the grid roller 30 and the pair of right and left pinch rollers 40 (see FIG. 3); and when the grid roller 30 is rotated in the direction of the arrow B by means of driving the stepping motor 31 (see FIG. 3), the recording paper 26 placed on the upper surface 14b of the base member 14 is conveyed in the direction of the arrow D, i.e. to the front side in the vertical scanning direction. On the other hand, when the grid roller 30 is rotated in the direction of the arrow C by driving the stepping motor 31 (see FIG. 3), the recording paper 26 placed on the upper surface of the base member 14 is conveyed in the direction of the arrow E, i.e. to the rear side in the vertical scanning direction.

[0040] In the above-described constitution, the undermentioned processes are conducted in the inkjet printer 10 as a result of the control by the microcomputer 100, whereby printing of the picture image represented by the image data for printing the color printing sample indicating colors of the inks accumulated in the ink tank section 32 and stored in the memory of the microcomputer 100, or printing of the picture image represented by the desired image data input from the outside through an interface is implemented.

[0041] Namely, when the recording paper 26 supplied on the base member 14 by means of the grid roller 30 rotated by driving the stepping motor 31 is conveyed up to the position from which the printing predetermined based on image data is to be started in the vertical scanning direction in the inkjet printer 10, an ink is jetted from any one ink head selected from the four ink heads 28a, 28b, 26c, and 28d on the recording paper 26 while transferring the recording paper 26 based on the image data from the printing start position to the front side in the vertical scanning direction, whereby the printing is conducted on the basis of the image data. Then, when the printing is completed, the recording paper 26 is transferred to the rear side in the vertical scanning direction to be returned to the printing start position, and thereafter, an ink is jetted from any one different ink head from that used in the printing completed and selected from the four ink heads 28a, 28b, 26c, and 28d on the recording paper 26, whereby the printing is conducted on the basis of the image data.

[0042] When the printing is completed, such process as that described above wherein the recording paper 26 is transferred to the rear side in the vertical scanning direction to be returned to the printing start position, and thereafter, an ink is jetted from any one different ink head from that used in the printing completed and selected from the four ink heads 28a, 28b, 26c, and 28d on the recording paper 26, whereby the printing is conducted on the basis of the image data is repeated until the inks are jetted from all the four ink heads 28a, 28b, 28c, and 28d on the recording paper 26.

[0043] Namely, any one of the four ink heads 28a, 28b, 28c, and 28d is selectively used in each printing operation in the inkjet printer 10, whereby a color printing is achieved.

[0044] As a result, the droplets adhered on the recording paper 26 which were jetted from any one of the four ink heads 28a, 28b, 28c, and 28d onto the recording paper 26 were dried during a period of time required for transferring the recording paper 26 from the front side to the rear side in the vertical scanning direction in case of completing any one printing operation by means of any one printing head in the four ink heads 28a, 28b, 28c, and 28d, so that the color mixture in the boundary surface of the inks adjacent to each other on the recording paper 26 can be prevented.

[0045] The order for selection in case of selecting any one of the four ink heads 28a, 28b, 28c, and 28d may be set previously, or it may be changed arbitrarily by a user.

[0046] In case of the printing as described above, each of the four ink heads 28a, 28b, 28c, and 28d jets an ink while moving reciprocately in the right and left directions along the horizontal scanning direction based on image data.

[0047] Namely, the holder 24 in which the ink head section 28 is installed transfers up to a predetermined position in the horizontal scanning direction with the transfer of the wire 22 due to winding of the wire 22; and the ink head section 28 jets an ink fed from the ink tank section 32 through the subsidiary tank 36 in response to image data.

[0048] Droplets of the ink thus jetted drop on the surface 26a of the recording paper 26, whereby the printing is carried out with respect to the recording paper 26.

[0049] Next, the printing processes executed in the inkjet printer 10 will be described by referring to the flowchart shown in FIG. 4 indicating specific processing sequences of the above-described printing processes.

[0050] It should be noted that the four ink heads 28a, 28b, 28c, and 28d are selected in the order of the ink head 28a → the ink head 28b → the ink head 28c → the ink head 28d; and the printing is made with respect to the recording paper 26 in this order in the processing sequences shown in the flowchart of FIG. 4.

[0051] First, when the start of the printing processing using the image data designated previously is instructed by inputting a predetermined command with respect to the microcomputer 100, the grid roller 30 is rotated by driving the stepping motor 31, whereby the recording paper 26 is conveyed up to the predetermined print starting position of the recording paper 26 based on the image data in the vertical scanning direction (step S402).

[0052] Then, a blue (cyan) ink is jetted onto the recording paper 26 from the ink head 28a selected while transferring the recording paper 26 from the print starting position to the front side in the vertical scanning direction based on the image data, whereby the printing on the basis of the image data is carried out (step S404).

[0053] Namely, when the grid roller 30 is rotated in the direction of the arrow B by driving the stepping motor 31, the recording paper 26 is transferred to the front side in the vertical scanning direction, and in addition, the holder 24 is moved in accordance with the movement of the wire 22 as a result of winding the wire 22, so that the ink head section 28 installed in the holder 24 is transferred in the horizontal scanning direction. Thus, the blue (cyan) ink fed to the ink head 28a from the ink tank 32a is jetted through the inkjet nozzle provided on the bottom of the ink head 28a on all the positions which are to be printed by the blue (cyan) ink in the recording paper 26 based on the image data as a result of transferring the recording paper 26 and the ink head section 28 as described above.

[0054] Then, when the printing operation for the blue (cyan) ink in the step S404 is completed, the step proceeds to the process in step S406 wherein the grid roller 30 is rotated in the direction of the arrow C by driving the stepping motor 31, whereby the recording paper 26 is transferred to the rear side in the vertical scanning direction to return the recording paper 26 up to the predetermined print starting position of the recording paper 26 based on the image data in the vertical scanning direction.

[0055] During the period of time extending from the transfer of the recording paper 26 from the front side to the rear side in the vertical scanning direction to the return of the recording paper 26 up to the predetermined print starting position, it is intended that droplets of the blue (cyan) ink are jetted onto the recording paper 26 from the ink head 28a so that they adhere on the recording paper 26, and these droplets are dried.

[0056] Next, an yellow ink is jetted onto the recording paper 26 from the ink head 28b selected while transferring the recording paper 26 from the print starting position to the front side in the vertical scanning direction based on the image data, whereby the printing on the basis of the image data is carried out (step S408).

[0057] Namely, when the grid roller 30 is rotated in the direction of the arrow B by driving the stepping motor 31, the recording paper 26 is transferred to the front side in the vertical scanning direction, and in addition, the holder 24 is moved in accordance with the movement of the wire 22 as a result of winding the wire 22, so that the ink head section 28 installed in the holder 24 is transferred in the horizontal scanning direction. Thus, the yellow ink fed to the ink head 28b from the ink tank 32b is jetted through the inkjet nozzle provided on the bottom of the ink head 28b on all the positions which are to be printed by the yellow ink on the recording paper 26 based on the image data as a result of transferring the recording paper 26 and the ink head section 28 as described above.

[0058] At the time of jetting the yellow ink onto the recording paper 26, since the blue (cyan) ink adhered on the recording paper 26 as a result of the processing of the step 404 has been dried, the color mixture in the boundary surface between the yellow ink and the blue (cyan) ink is prevented.

[0059] Then, when the printing operation for the yellow ink in the step S408 is completed, the step proceeds to the process in step S410 wherein the grid roller 30 is rotated in the direction of the arrow C by driving the stepping motor 31, whereby the recording paper 26 is transferred to the rear side in the vertical scanning direction to return the recording paper 26 up to the predetermined print starting position of the recording paper 26 based on the image data in the vertical scanning direction.

[0060] During the period of time extending from the transfer of the recording paper 26 from the front side to the rear side in the vertical scanning direction to the return of the recording paper 26 up to the predetermined print starting position, it is intended that droplets of the yellow ink are jetted onto the recording paper 26 from the ink head 28b so that they adhere on the recording paper 26, and these droplets are dried.

[0061] Next, a red (magenta) ink is jetted onto the recording paper 26 from the ink head 28c selected while transferring the recording paper 26 from the print starting position to the front side in the vertical scanning direction based on the image data, whereby the printing on the basis of the image data is carried out (step S412).

[0062] Namely, when the grid roller 30 is rotated in the direction of the arrow B by driving the stepping motor 31, the recording paper 26 is transferred to the front side in the vertical scanning direction, and in addition, the holder 24 is moved in accordance with the movement of the wire 22 as a result of winding the wire 22, so that the ink head section 28 installed in the holder 24 is transferred in the horizontal scanning direction. Thus, the red (magenta) ink fed to the ink head 28c from the ink tank 32c is jetted through the inkjet nozzle provided on the bottom of the ink head 28c on all the positions which are to be printed by the red (magenta) ink on the recording paper 26 based on the image data as a result of transferring the recording paper 26 and the ink head section 28 as described above.

[0063] At the time of jetting the red (magenta) ink onto the recording paper 26, since the blue (cyan) ink adhered on the recording paper 26 as a result of the processing of the step 404 as well as the yellow ink adhered on the recording paper 26 as a result of the processing of the step 408 have been dried, the color mixture in the boundary surfaces among the red (magenta) ink, the blue (cyan) ink, and the yellow ink is prevented.

[0064] Then, when the printing operation for the red (magenta) ink in the step S412 is completed, the step proceeds to the process in step S414 wherein the grid roller 30 is rotated in the direction of the arrow C by driving the stepping motor 31, whereby the recording paper 26 is transferred to the rear side in the vertical scanning direction to return the recording paper 26 up to the predetermined print starting position of the recording paper 26 based on the image data in the vertical scanning direction.

[0065] During the period of time extending from the transfer of the recording paper 26 from the front side to the rear side in the vertical scanning direction to the return of the recording paper 26 up to the predetermined print starting position, it is intended that droplets of the red (magenta) ink are jetted onto the recording paper 26 from the ink head 28c so that they adhere on the recording paper 26, and these droplets are dried.

[0066] Next, a black ink is jetted onto the recording paper 26 from the ink head 28d selected while transferring the recording paper 26 from the print starting position to the front side in the vertical scanning direction based on the image data, whereby the printing on the basis of the image data is carried out (step S416), and this printing process is completed.

[0067] Namely, when the grid roller 30 is rotated in the direction of the arrow B by driving the stepping motor 31, the recording paper 26 is transferred to the front side in the vertical scanning direction, and in addition, the holder 24 is moved in accordance with the movement of the wire 22 as a result of winding the wire 22, so that the ink head section 28 installed in the holder 24 is transferred in the horizontal scanning direction. Thus, the black ink fed to the ink head 28d from the ink tank 32d is jetted through the inkjet nozzle provided on the bottom of the ink head 28d on all the positions which are to be printed by the black ink on the recording paper 26 based on the image data as a result of transferring the recording paper 26 and the ink head section 28 as described above.

[0068] At the time of jetting the black ink onto the recording paper 26, since the blue (cyan) ink adhered on the recording paper 26 as a result of the processing of the step 404, the yellow ink adhered on the recording paper 26 as a result of the processing of the step 408, and the red (magenta) ink adhered on the recording paper 26 as a result of the processing of the step 412 have been dried, the color mixture in the boundary surfaces among the black ink, the blue (cyan) ink, the yellow ink, and the red (magenta) ink is prevented.

[0069] In accordance with the above-described printing processing, the inks having four different colors, i.e. blue (cyan), yellow, red (magenta), and black are individually printed on the recording paper 26, whereby the color printing of the image represented by image data is made on the recording paper 26, and the color mixture of four color inks is prevented.

[0070] Thus, a color printing sample of high quality is obtained without accompanying any color mixture in the boundary surfaces of the inks applied according to the inkjet printer 10 in the case when the color printing sample represented by the colors of the inks accumulated in the tank section 32 is printed.

[0071] In the case where a medium used is a material which absorbs a liquid ink such as the recording paper 26, the ink printed on such medium dries comparatively rapidly at even an ordinary temperature. On the other hand, in the case where a medium used is either a material which does not absorb a liquid ink such as a resin material, a metallic material, and a glass material, or a material which absorbs hardly a liquid ink such as a recording paper the surface of which is treated, there is such a possible solution as described hereinbelow in the present invention.

[0072] Namely, in the case where the grid roller 30 is rotated in the direction of the arrow C by driving the stepping motor 31 after completing the printing of each of different color inks, so that a medium (the recording paper 26 in the above-described embodiment) is transferred to the rear side in the vertical scanning direction, and the medium (the recording paper 26 in the above-described embodiment) is returned up to a predetermined print starting position of the medium (the recording paper 26 in the above-described embodiment), a rate of the return is made to be adjustable, whereby the medium may be returned for a period of time sufficient for drying the ink.

[0073] As a result, there is no color mixture of inks in the boundary surfaces of these inks adjacent to each other which are printed on the same medium, so that a printed image of high quality is obtained according to the inkjet printer 10 of the present invention in even the case where a medium used is either a material which does not absorb a liquid ink such as a resin material, and a metallic material, or a material which absorbs hardly a liquid ink such as a recording paper the surface of which is treated.

[0074] Although a case where four different color inks, i.e. a blue (cyan) ink, an yellow ink, a red (magenta) ink, and a black ink are applied has been described in the above-described embodiment, the invention is not limited thereto, as a matter of course, the present invention is applicable for the case where two or more different color inks are used wherein the number of ink heads constituting the ink head section 28, and the number of ink tanks constituting the ink tank section 32 may be increased or decreased in response to the number of ink colors applied.

[0075] For example, six different color inks may be used with four different colors described above and two another colors. Further, eight different liquids may be used. More specifically, inks representing CMYK described above and RGB with one finishing liquid may be used. One finishing ink may include varnish and inhibitor and so on. In these situations, the color order or the liquid order may be freely changed depending on the situations.

[0076] Still further, the inkjet printer may be one with a cutting machine, or may be used for proofing.

[0077] Still further, although the inkjet printer is stand-alone in the embodiment, a plurality of inkjet printers may be installed in the cascaded style or a plurality of inkjet printers may be installed in different buildings in the cascaded style as long as the printers are connected in some way.

Claims

1. An inkjet printer (10) jetting inks having a plurality of colors in response to image data onto a medium (26) being a printing object according to an inkjet process, comprising:

- a medium transfer means for transferring reciprocately the medium (26) along predetermined directions;

- a plurality of ink heads (28a, 28b, 28c, 28d) each containing a different color ink and conducting a printing with respect to said medium (26) by jetting the inks contained onto said medium (26) in response to image data according to the inkjet process; and

- a control means (100) for
selecting any one of the plurality of ink heads (28a, 28b, 28c, 28d) to conduct a printing with respect to said medium (26) while transferring said medium (26) from a predetermined print starting position in a direction of the predetermined directions by controlling said medium transfer means,
after completing the printing, controlling said medium transfer means to transfer said medium (26) in another direction of said predetermined directions, thereby returning said medium (26) to said printing start position,
and selecting any one of said plurality of ink heads (28a, 28b, 28c, 28d) different from the ink head that completed the printing to conduct another printing with respect to said medium (26), after drying the former printed color ink.

2. The inkjet printer as claimed in claim 1, wherein:

said control means (100) is constructed such that it selects any one of said plural ink heads (28a, 28b, 28c, 28d) in a predetermined order, and implements a printing with respect to said medium (26) by means of all said plural ink heads.

3. The inkjet printer as claimed in any one of claims 1 and 2, wherein:

said medium transfer means includes

a grid roller (30) rotated by driving a drive means and

pinch rollers (40) energized with respect to said grid roller (30);

and sandwiches said medium (26) between said grid roller (30) and said pinch rollers (40), and changes movably the rotational direction of said grid roller (30) to transfer reciprocately said medium (26) along predetermined directions.

4. The inkjet printer as claimed in claim 3, wherein:

grid roller (30) and pinch rollers (40) are adapted to return said medium (26) from an printing end position to the predetermined print starting position.

5. A printing method with an inkjet printer (10) in which plural color inks are jetted onto a medium (26) being a printing object in response to image data according to an inkjet process thereby to conduct a printing; comprising the steps of:

- selecting any one of a plurality of ink heads (28a, 28b, 28c, 28d) to implement the printing with respect to the medium (26) while controlling a medium transfer means transferring reciprocately said medium (26) along predetermined directions to transfer said medium (26) from a predetermined print start position in a direction of said predetermined directions, said plurality of ink heads (28a, 28b, 28c, 28d) containing different color inks, respectively,

- and jetting the inks contained onto said medium (26) in response to image data according to the inkjet process, respectively, to conduct the printing;

- after completing said printing, controlling said medium transfer means to transfer said medium (26) along another direction of said predetermined directions thereby returning said medium (26) to said print starting position; and

- selecting any one of said plurality of ink heads (28a, 28b, 28c, 28d) different from the ink head which completed said printing to implement a printing with respect to said medium (26) after drying the former printed color ink.

6. The printing method by the inkjet printer as claimed in claim 5, wherein:

any one of said plurality of ink heads (28a, 28b, 28c, 28d) is selected in a predetermined order, and a printing is implemented with all said plurality of ink heads (28a, 28b, 28c, 28d).

7. The printing method as claimed in any one of claims 5 and 6, wherein:

said medium transfer means includes a grid roller (30) rotated by driving a drive means and pinch rollers (40) energized with respect to said grid roller (30);

and sandwiches said medium (26) between said grid roller (30) and said pinch rollers (40), and changes movably the rotational direction of said grid roller (30) to transfer reciprocately said medium (26) along predetermined directions, wherein by said grid roller (30) and pinch rollers (40) said medium (26) is returned from an printing end position to the predetermined print starting position.

Ansprüche

1. Tintenstrahldrucker (10), welcher Tinten, welche eine Mehrzahl von Farben haben, in Antwort auf Abbildungsdaten auf ein Medium (26), welches ein Druckobjekt ist, gemäß einem Tintenstrahlvorgang ausstößt, aufweisend:

- ein Medium-Transfermittel, um das Medium (26) entlang vorbestimmter Richtungen hin- und herbewegend zu transferieren;

- eine Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d), von welchen jeder eine Tinte verschiedener Farbe enthält und einen Druck hinsichtlich des Mediums (26) durch ein Ausstoßen der beinhalteten Tinten auf das Medium (26) in Antwort auf Abbildungsdaten gemäß dem Tintenstrahlvorgang ausführt; und

- ein Steuer- oder Regelmittel (100) zum
Auswählen irgendeines der Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d), um einen Druck hinsichtlich des Mediums (26) durchzuführen, während es das Medium (26) durch Steuern oder Regeln des Medium-Transfermittels von einer vorbestimmten Druckstartposition in eine Richtung der vorbestimmten Richtungen transferiert,
Steuern oder Regeln des Medium-Transfermittels nach der Fertigstellung des Druckes, um das Medium (26) in eine andere Richtung der vorbestimmten Richtungen zu transferieren, wodurch das Medium (26) zu der Druckstartposition zurückgebracht wird,
und Auswählen irgendeines der Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d) unterschiedlich von dem Tintenkopf, welcher den Druck vollendet hat, um einen anderen Druck hinsichtlich des Mediums (26) nach dem Trocknen der vormalig gedruckten Farbtinte durchzuführen.

2. Tintenstrahldrucker nach Anspruch 1, wobei:

das Steuer- oder Regelmittel (100) derart konstruiert ist, dass es irgendeinen der Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d) in einer vorbestimmten Reihenfolge auswählt und einen Druck hinsichtlich des Mediums (26) mittels aller der Mehrzahl von Tintenköpfen durchführt.

3. Tintenstrahldrucker nach einem der Ansprüche 1 oder 2, wobei:

das Medium-Transfermittel aufweist:

eine Rasterrolle oder Rasterwalze (30), welche durch Antreiben eines Antriebsmittels gedreht wird, und

Quetschrollen (40), welche hinsichtlich der Rasterrolle (30) mit Energie versorgt werden;

und das Medium (26) zwischen der Rasterrolle (30) und den Quetschrollen (40) sandwichartig einschließt,

und die Drehrichtung der Rasterrolle (30) beweglich ändert, um das Medium (26) entlang vorbestimmter Richtungen hin- und herbewegend zu transferieren.

4. Tintenstrahldrucker nach Anspruch 3, wobei:

die Rasterrolle (30) und die Quetschrollen (40) angepasst sind, um das Medium (26) von einer Druckendposition zu der vorbestimmten Druckstartposition zurück zu bringen.

5. Druckverfahren mit einem Tintenstrahldrucker (10), in welchem mehrere Farbtinten auf ein Medium (26), welches ein Druckobjekt ist, in Antwort auf Abbildungsdaten gemäß einem Tintenstrahlvorgang ausgestoßen werden, um dadurch einen Druck durchzuführen; aufweisend die Schritte:

- Auswählen irgendeines einer Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d), um das Drucken hinsichtlich des Mediums (26) zu implementieren, während ein Medium-Transfermittel geregelt oder gesteuert wird, welches hin- und herbewegend das Medium (26) entlang vorbestimmter Richtungen transferiert, um das Medium (26) von einer vorbestimmten Druckstartposition in eine Richtung der vorbestimmten Richtungen zu transferieren, wobei die Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d) verschiedene Farbtinten beinhaltet,

- und Ausstoßen der beinhalteten Tinten auf das Medium (26) in Antwort auf Abbildungsdaten entsprechend dem Tintenstrahlvorgang, um das Drucken durchzuführen;

- nach der Fertigstellung des Druckens Steuern oder Regeln des Medium-Transfermittels, um das Medium (26) entlang einer anderen Richtung der vorbestimmten Richtungen zu transferieren, wodurch das Medium (26) zu der Druckstartposition zurückgebracht wird; und

- Auswählen irgendeines der Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d) unterschiedlich von dem Tintenkopf, welcher das Drucken vollendet hat, um einen Druck hinsichtlich des Mediums (26) nach dem Trocknen der vormalig gedruckten Farbtinte zu implementieren.

6. Druckverfahren durch den Tintenstrahldrucker wie in Anspruch 5 beansprucht, wobei:

irgendeiner der Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d) in einer vorbestimmten Reihenfolge ausgewählt wird und ein Druck mit allen der Mehrzahl von Tintenköpfen (28a, 28b, 28c, 28d) durchgeführt wird.

7. Druckverfahren wie in irgendeinem der Ansprüche 5 und 6 beansprucht, wobei:

das Medium-Transfermittel eine Rasterrolle (30), welche durch ein Antreiben eines Antriebsmittels gedreht wird, und Quetschrollen (40) aufweist, welche hinsichtlich der Rasterrolle (30) mit Energie versorgt werden;

und das Medium (26) zwischen der Rasterrolle (30) und den Quetschrollen (40) sandwichartig einschließt,

und beweglich die Drehrichtung der Rasterrolle (30) verändert, um das Medium (26) entlang vorbestimmter Richtungen hin- und herbewegend zu transferieren, wobei durch die Rasterrolle (30) und die Quetschrollen (40) das Medium (26) von einer Druckendposition zu der vorbestimmten Druckstartposition zurückgebracht wird.

Revendications

1. Imprimante par jet d'encre (10) projetant des encres d'une pluralité de couleurs en réponse à des données d'image sur un support (26) qui est un objet à imprimer selon un procédé d'impression par jet d'encre, comportant:

- des moyens de transfert de support permettant de transférer, selon un mouvement de va et vient, le support (26) le long de directions prédéterminées ;

- une pluralité de têtes d'encre (28a, 28b, 28c, 28d) contenant, chacune, une encre de couleur différente et réalisant une impression relative au dit support (26) en projetant les encres contenues sur ledit support (26) en réponse à des données d'image selon le procédé d'impression par jet d'encre ; et

- des moyens de commande (100) pour sélectionner l'une quelconque de la pluralité de têtes d'encre (28a, 28b, 28c, 28d) en vue de
réaliser une impression par rapport au dit support (26) tout en transférant ledit support (26) d'une position de démarrage de l'impression prédéterminée suivant une direction des directions prédéterminées en commandant lesdits moyens de transfert de support,
après achèvement de l'impression, commander lesdits moyens de transfert de support afin de transférer ledit support (26) dans une autre direction desdites directions prédéterminées, renvoyant, de ce fait, ledit support (26) vers ladite position de démarrage de l'impression,
et sélectionner l'une quelconque de ladite pluralité de têtes d'encre (28a, 28b, 28c, 28d) différente de la tête d'encre qui a achevé l'impression afin de réaliser une autre impression relative au dit support (26), après le séchage de l'encre de couleur imprimée précédemment.

2. Imprimante par jet d'encre selon la revendication 1, dans laquelle : lesdits moyens de commande (100) sont réalisés de telle sorte qu'ils sélectionnent l'une quelconque parmi plusieurs têtes d'encre (28a, 28b, 28c, 28d) dans un ordre prédéterminé, et mettent en oeuvre une impression relative au dit support (26) au moyen de l'ensemble desdites plusieurs têtes d'encre.

3. Imprimante par jet d'encre selon l'une quelconque des revendications 1 et 2, dans laquelle :, lesdits moyens de transfert de support comportent un rouleau à grille (30) mis en rotation par l'entraînement des moyens de commande et des rouleaux de contre-pression (40) activés par rapport au dit rouleau à grille ; et prennent en sandwich ledit support (26) entre ledit rouleau à grille (30) et lesdits rouleaux de contre-pression (40), et modifient de façon amovible la direction de rotation dudit rouleau à grille (30) afin de transférer suivant un mouvement de va-et-vient ledit support (26) le long de directions prédéterminées.

4. Imprimante par jet d'encre selon la revendication 3, dans laquelle : le rouleau à grille (30) et les rouleaux de contre-pression (40) sont adaptés pour renvoyer ledit support (26) d'une position finale de l'impression vers la position prédéterminée de démarrage de l'impression.

5. Procédé d'impression avec une imprimante par jet d'encre (10) dans lequel des encres de plusieurs couleurs sont projetées sur un support (26) qui est un objet à imprimer en réponse à des données d'image selon un procédé d'impression par jet d'encre afin de réaliser, de ce fait, une impression ; comportant les étapes comprenant de :

- sélectionner l'une quelconque d'une pluralité de têtes d'encre (28a, 28b, 28c, 28d) pour mettre en oeuvre l'impression relative au support (26) tout en commandant à des moyens de transfert de support de transférer suivant un mouvement de va-et-vient ledit support (26) le long de directions prédéterminées afin de transférer ledit support (26) d'une position prédéterminée de départ de l'impression suivant une direction desdites directions prédéterminées, ladite pluralité de têtes d'encre (28a, 28b, 28c, 28d) contenant des encres de couleurs différentes, respectivement ;

- et projeter les encres contenues sur ledit support (26) en réponse à des données d'image selon le procédé d'impression par jet d'encre, respectivement, afin de réaliser l'impression ;

- après achèvement de ladite impression, commander aux dits moyens de transfert de support de transférer ledit support (26) le long d'une autre direction parmi lesdites directions prédéterminées renvoyant, de ce fait, ledit support (26) à ladite position de démarrage de l'impression ; et

- sélectionner l'une quelconque de ladite pluralité de têtes d'encre (28a, 28b, 28c, 28d) différente de la tête d'encre qui a achevé ladite impression afin de mettre en oeuvre une impression relative au dit support (26) après le séchage de l'encre de couleur imprimée précédemment.

6. Procédé d'impression avec l'imprimante par jet d'encre selon la revendication 5, dans lequel : l'une quelconque de ladite pluralité des têtes d'encre (28a, 28b, 28c, 28d) est sélectionnée dans un ordre prédéterminé et dans lequel une impression est mise en oeuvre avec l'ensemble de ladite pluralité des têtes d'encre (28a, 28b, 28c, 28d).

7. Procédé d'impression selon l'une quelconque des revendications 5 et 6, dans lequel : lesdits moyens de transfert de support comprennent un rouleau à grille (30) mis en rotation par l'entraînement de moyens de commande et des rouleaux de contre-pression (40) activés par rapport au dit rouleau à grille (30) ; et prennent en sandwich ledit support (26) entre ledit rouleau à grille (30) et lesdits rouleaux de contre-pression (40), et changent de façon amovible la direction de rotation dudit rouleau à grille (30) afin de transférer suivant un mouvement de va-et-vient ledit support (26) le long de directions prédéterminées, dans lequel par l'intermédiaire dudit rouleau à grille (30) et desdits rouleaux de pression (40), ledit support (26) est renvoyé d'une position finale de l'impression vers la position prédéterminée de démarrage de l'impression.

Drawing