Image forming apparatus, image forming system, and method of forming image

Abstract

 An image forming apparatus includes: an image forming unit (34) that forms an image on a recording medium based on designation of the image and image formation; a communication unit (41, 44) that communicates with an external apparatus; a determining unit (32) that determines whether or not to reduce a speed at which the image forming unit (34) forms the image based on the designation, when the communication unit (41, 44) receives a power reduction command that requests to reduce power consumption; and a control unit (31, 32) that allows the image forming unit (34) to form the image on the recording medium at a second speed lower than a first speed that is determined in advance, when the determining unit (32) determines the speed to reduce.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2010-202413 filed in Japan on September 9, 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] The present invention relates to an image forming apparatus, an image forming system, and a method of forming an image.

2. Description of the Related Art

[0003] An enhanced function-type electric power meter, which has a communication function for communicating with devices as loads and has a management function for managing the devices, are started to be widely used worldwide. Such an electric power meter is a new electronic-type meter and is called as a smart meter. In the smart meter, a wireless communication function as a communication function is built in, and the smart meter is connected to apparatuses such as an air conditioner, a lighting device, a thermometer, a security apparatus, or an image forming apparatus that are equipped in a house or a business site. Furthermore, in the future, an application is considered in which an electric power supplier performs power control to each device through the smart meter connected with a network. Described in more detail, an application is considered in which the set temperature of an air conditioner is raised by +2°C by an electric power supplier at the peak time of power consumption in the summer season. In the image forming apparatus, power control is known (for example, see Japanese Patent Application Laid-open No. 2003-209924) in which, in a case where there is no room for the electric power supplied to the image forming apparatus, the operating mode of the image forming apparatus is forcedly switched into a power saving mode, in which the supply of electric power is suppressed, or an operating mode called a power reduction mode in which the copying productivity is reduced, instead of the power saving mode in a case where a copying operation is performed by the image forming apparatus. In technology disclosed in Japanese Patent Application Laid-open No. 2003-209924, in the power reduction mode, for example, the linear velocity is limited when a copying is operated.

[0004] In the example of the air conditioner at the peak time of power consumption in the summer season, a case where the electric power supplier forcibly raises the setting of the temperature of the air conditioner by several °C can reliably result in reduction of the power consumption of the air conditioner. However, in a conventional image forming apparatus, the switching of the operating mode thereof to the power-reduction copy mode may not necessarily result in the power consumption. As a simple example, in a case where a copying operation is performed for only one sheet, it is understood that the copy productivity is preferably not be reduced. For example, in a case where the copy productivity is reduced by lowering the linear velocity at the time of performing a copying operation or the like even in a case where a copying operation is performed for only one sheet, the operating time until the sheet for which the copying operation is performed is discharged is lengthened, and, as a result, the power consumption may increase to the contrary of the intention. In such a case, by reducing the copy productivity, the user convenience is not degraded, and even the power consumption is not reduced.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to at least partially solve the problems in the conventional technology.

[0006] The invention is contrived in consideration of the description presented above, and an object thereof is to provide an image forming apparatus, an image forming system, and a method of forming an image that are capable of reliably realizing reduction of power consumption in accordance with a command transmitted from an electric power supplier in consideration of the user convenience.

[0007] According to an aspect of the present invention, there is provided an image forming apparatus including: an image forming unit that forms an image on a recording medium based on designation of the image and image formation; a communication unit that communicates with an external apparatus; a determining unit that determines whether or not to reduce a speed at which the image forming unit forms the image based on the designation, when the communication unit receives a power reduction command that requests to reduce power consumption; and a control unit that allows the image forming unit to form the image on the recording medium at a second speed lower than a first speed that is determined in advance, when the determining unit determines the speed to reduce.

[0008] According to another aspect of the present invention, there is provided an image forming system in which an image forming apparatus and an external apparatus managing electric power of the image forming apparatus are connected to each other, wherein the external apparatus includes a transmission unit that transmits a power reduction command requesting to reduce power consumption to the image forming apparatus; and the image forming apparatus includes: an image forming unit that forms an image on a recording medium based on designation of the image and image formation; a communication unit that communicates with the external apparatus; a determining unit that determines whether or not to reduce a speed at which the image forming unit forms the image based on the designation, when the communication unit receives the power reduction command; and a control unit that allows the image forming unit to form the image on the recording medium at a second speed that is lower than a first speed that is determined in advance, when the determining unit determines the speed is to be reduced.

[0009] According to another aspect of the present invention, there is provided an method of forming an image that is performed by an image forming apparatus including an image forming unit that forms an image on a recording medium, a communication unit that communicates with an external apparatus, a determining unit, and a control unit, based on designation of the image and image formation, the method including: determining whether or not to reduce a speed at which the image forming unit forms the image based on the designation detennined by the determining unit, when a power reduction command requesting to reduce power consumption is received by the communication unit; and controlling to allow the image forming unit to form the image on the recording medium at a second speed that is lower than a first speed that is set in advance, when the speed is determined to be reduced by the determining unit.

[0010] The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 

Fig. 1 is a diagram illustrating a smart meter.

Fig. 2 is a diagram illustrating a simplified example of a connection between the smart meter and an image forming apparatus;

Fig. 3 is a diagram illustrating an example of the hardware configuration of the image forming apparatus.

Fig. 4 is a diagram illustrating an exemplary overview of an operation display unit;

Fig. 5 is a diagram illustrating an example of the functional configuration of a control unit;

Fig. 6 is a diagram illustrating an exemplary display of a message indicating that power supply is suppressed by a power supplier;

Fig. 7 is a flowchart illustrating the processing sequence of the image forming apparatus when a power reduction command is received from the smart meter;

Fig. 8 is a flowchart illustrating the processing sequence of the image forming apparatus when a power reduction cancelling command is received from the smart meter;

Fig. 9 is a flowchart illustrating the processing sequence of a case where the image forming apparatus performs printing as a copying operation or a printing operation;

Fig. 10 is a diagram illustrating the advantages of an embodiment;

Fig. 11 is a diagram illustrating the advantages of the embodiment;

Fig. 12 is a flowchart illustrating the processing sequence of a case where an image forming apparatus according to a second embodiment performs printing in accordance with a printing request;

Fig. 13 is a flowchart illustrating the processing sequence of a case where an image forming apparatus according to a third embodiment performs printing in accordance with a printing request;

Fig. 14 is a flowchart illustrating the processing sequence of a case where an image forming apparatus according to a modified example performs printing in accordance with a printing request;

Fig. 15 is a diagram illustrating an example of a setting screen used for a user to perform an operation input of setting a CPM value (speed) as low productivity according to a modified example; and

Fig. 16 is a diagram illustrating an exemplary display of a message according to a modified example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, image forming apparatuses, an image forming system, and a method of forming an image according to embodiments will be described in detail with reference to the accompanying drawings.

First Embodiment

[0013] Fig. 1 is a diagram illustrating a smart meter. The smart meter is installed to each house or office. Devices as loads such as an air conditioner, a lighting device, and an image forming apparatus that are placed inside each house or office are connected to each smart meter. The electric power delivered from a power supplier is supplied to each smart meter through a power pole that is connected to a power line and is supplied to each load through the smart meter.

[0014] While a conventional electric power meter only measures the power (power consumption) consumed by the loads placed inside a house or an office, the smart meter is of an enhanced function type in which a function for transmitting a measurement result to a power supplier through wireless communication or communication using power lines (it is unnecessary for a person to read a meter), a communication function for communicating with the loads, a power management function for managing the power of the loads, or the like is further included in addition to a function for measuring the power consumption. As a specific example of the power management function, there is a function for allowing a power supplier to raise the temperature setting of an air conditioner placed inside each house or office by several degrees centigrade or set the temperature of the air conditioner to predetermined temperature (for example, 28°C that is temperature recommended by a Cool Biz campaign) through smart meters at the time of peak power consumption in the summer season. Accordingly, the power consumption can be reduced.

[0015] Fig. 2 is a diagram illustrating a simplified example of a connection between the smart meter and an image forming apparatus. As illustrated in the figure, the smart meter that is connected to a power pole through power lines or AC power supply lines and the image forming apparatus are connected to each other through AC power supply lines. From the smart meter to the image forming apparatus, power is supplied through the AC power supply lines. Although not illustrated in the figure, a distribution board and a plug socket are present between the smart meter and the image forming apparatus. In addition, the image forming apparatus includes a wireless communication unit that performs wireless communication, and, as illustrated in Fig. 2, can communicate with the smart meter in a wireless manner. In such a configuration, the smart meter can realize at least the power management function of the image forming apparatus. The power management function of the image forming apparatus is a function for determining whether or not the image forming apparatus is started, transmitting a command used for reducing the power consumption of the image forming apparatus at the time of peak power consumption in the summer season to the image forming apparatus, similarly to the air conditioner, or the like.

[0016] Next, the hardware configuration of the image forming apparatus according to this embodiment will be described with reference to Fig. 3. The image forming apparatus includes a main power supply switch (SW) 30, a power supply unit (PSU) 31, a control unit 32, an operation display unit 33, a fixation unit 34, a variety of motors 35, and a scanning unit (not illustrated in the figure). The main power supply SW 30 is a switch that is switched between On and Off in accordance with a user operation and switches between supplying and not supplying of an alternating current (AC) voltage from an AC power supply to the PSU 31 in accordance with the switching to On or Off. The PSU 31 includes a DC voltage generating unit 36 and a heater driving unit 37. The DC voltage generating unit 36 generates a DC voltage by converting the AC voltage supplied from the AC power supply through the main power supply SW 30 into the DC voltage and supplies the generated DC voltage to the control unit 32. The heater driving unit 37 supplies the AC voltage supplied from the AC power supply through the main power supply SW 30 to the fixation unit 34 or the scanning unit. The scanning unit scans an image from an original in accordance with a user operation input that instructs a copy operation through the operation display unit 33 to be described later. After a toner image of a latent image formed on a photosensitive element is transferred on a paper sheet (recording medium) based on the image scanned from the original by the scanning unit or print instruction data, which is transmitted from an image processing apparatus, to be described later, the fixation unit 34 fixes the toner image on the paper sheet so as to form an image on the paper sheet, thereby performing printing as a copying operation or a printing operation. The motors 35 are of various types of motors that are used for driving the photosensitive element, a paper feeding roller, and the like. The operation display unit 33 is configured by integrally forming an operation unit such as operation keys or operation buttons to which an operation is input from a user and a display unit such as a liquid crystal display that displays information.

[0017] Fig. 4 is a diagram illustrating an exemplary overview of the operation display unit 33. In the figure, reference numerals 2, 3, 5 to 8, 10, 12, and 15 to 21 are hardware keys such as operation keys or operation buttons that are configured by hardware, a reference numeral 4 is a touch panel-type display, and reference numerals 9, 11, 13, and 14 are light emitting diodes (LEDs) that are used for displaying the statuses of the image forming apparatus.

[0018] The description will be continued with reference back to Fig. 3. When an AC voltage is supplied from the DC voltage generating unit 36, the control unit 32 supplies the AC voltage to the operation display unit 33 or the variety of motors 35. In addition, the control unit 32 includes a central processing unit (CPU) 38, a random access memory (RAM) 39, a read only memory (ROM) 40, a wireless communication unit 41, a hard disk drive (HDD) 42, an ASIC 43, and a communication unit 44 and controls the overall operation of the image forming apparatus. The CPU 38 realizes various functions by controlling each device included in the image forming apparatus by reading out and executing various programs that are stored in the ROM 40 or the HDD 42. The ROM 40 stores various programs or various kinds of data therein. The RAM 39 temporarily stores various programs that are executed by the CPU 38 or various kinds of data therein. The HDD 42 stores various programs and various kinds of data such as various types of image data. The wireless communication unit 41 communicates with an external device such as the smart meter in a wireless manner. The ASIC 43 is an integrated circuit (IC), which includes hardware elements used for image processing, dedicated only for image processing and controls the driving of the variety of motors 35 and the fixation unit 34. The communication unit 44 communicates with an external device such as an information processing apparatus through a network and, for example, receives print instruction data used for instructing printing of an image from the information processing apparatus.

[0019] Next, the functional configuration of the control unit 32 according to this embodiment will be described with reference to Fig. 5. The image forming apparatus includes: a smart-meter communication control unit 50; a display control unit 51; a printing control unit 52; and a storage unit 53. The smart-meter communication control unit 50, the display control unit 51, and the printing control unit 52 are generated, for example, in the RAM 39 when the CPU 38 executes various programs stored in the ROM 40 or the HDD 42. The storage unit 53, for example, is generated in a storage area that is secured in the ROM 40 or the HDD 42.

[0020] The smart-meter communication control unit 50 receives a command from the smart meter through the wireless communication unit 41 and is an example of a communication unit. Described in more detail, when a power reduction command is received from the smart meter through the wireless communication unit 41, the smart-meter communication control unit 50 stores a power reduction flag having a value of "1" in the RAM 39. The power reduction command requests reduction of power consumption and, in other words, the power reduction command is a command, which is transmitted from a power supplier, requesting reduction of the level of power consumption. On the other hand, when a power reduction cancelling command is received from the smart meter through the wireless communication unit 41, the smart-meter communication control unit 50 sets the value of the power reduction flag stored in the RAM 39 as "0". The power reduction cancelling command is a command that is used for cancelling the request for reduction of power consumption and is a command that is used for cancelling the request for lowering the level of power consumption.

[0021] The printing control unit 52 controls a printing operation that is performed in a case where there is a printing request; and the printing control unit 52 determines whether or not a transition to the power reduction mode is to be made based on a printing condition that is designated in a printing request and allows the fixation unit 34 to perform a printing operation based on a determination result. This is an example of a control unit. In addition, here, in the image forming apparatus, in a case where there is an operation input used for instructing a copy operation through the operation display unit 33, or print instruction data is received from the image processing apparatus through the communication unit 44, it is assumed that there is an image formation instruction used for instructing image formation with a printing condition designated as a printing request. When performing an operation input for instructing a copy operation, it is assumed that a user designates the number of target paper sheets (referred to as the requested number of prints) for which a copy operation is performed as the printing condition. In addition, also in the print instruction data, it is assumed that the number of target paper sheets for which a printing operation is performed is designated as the printing condition. In a case where the transition to the power reduction mode is determined, the printing control unit 52 allows the fixation unit 34 to perform a printing operation at reduced productivity. In addition, as an index that represents the productivity of a copying machine, there is a copy per minute (CPM). This is a speed that represents the number of paper sheets for which a copy operation is performed in one minute. In addition, as an index that represents the productivity for a case of a printer, there is a page per minute (PPM). This is a speed that represents the number of paper sheets for which a printing operation is performed in one minute. In the power reduction mode, in a case where printing is controlled in accordance with an operation input instructing a copy operation, the printing control unit 52 performs control such that printing is performed at reduced CPM (speed), and, in a case where printing is controlled in accordance with reception of the print instruction data, the printing control unit 52 performs control such that printing is performed at reduced PPM (speed). In other words, the power reduction mode is a mode in which the speed relating to the printing operation is reduced. Hereinafter, for convenience of the description, also in a case where printing is performed, the description will be presented by using the CPM. For example, in monochrome printing for A4 paper sheets, when the CPM is a speed of 75 sheets/minute in a case where there is no transition to the power reduction mode, the CPM is a speed of 65 sheets/minute in a case where the transition to the power reduction mode made. The former productivity is referred to as normal productivity, and the latter productivity is referred to as low productivity. In addition, as a method of reducing the productivity, that is, reducing the speed relating to a printing operation, there is a method in which the rotation speeds of the variety of motors 35 driving the photosensitive element and the like are reduced in performing printing or a method in which an interval (referred to as a paper passing interval), through which a target sheet for printing is passed, is increased. Here, for example, the latter method is used.

[0022] Here, the CPM of 75 sheets/minute is used for a specification under the copy condition of "a monochrome copy" and "a copy paper sheet of A4 in the vertical direction". In the case of a color copy, the CPM (the number of copy outputs in one minute) may be different from that in the case of a monochrome copy. Similarly, also in a case where the size of the copy paper sheet is A3 or the like, the CPM (the number of copy outputs in one minute) is different from that in the case where the size of the copy paper sheet is A4 in the vertical direction. Since the CPM changes in accordance with the copy condition, the numerical value of the specified number of sheets changes in accordance with a change in the CPM. In this embodiment, the specified number for each copy condition is stored. Hereinafter, the numerical values of the CPM and the number of sheets, for convenience of the description, will be described on the premise of "a monochrome copy" and "a copy sheet of A4 in the vertical direction".

[0023] Next, how to determine whether or not to transit into the power reduction mode based on the printing condition will be described. In this embodiment, the printing control unit 52 determines to transit into the power reduction mode in a case where the requested number of prints is a specified number of sheets or more, and determines not to transit into the power reduction mode in a case where the requested number of prints is less than the specified number of sheets. Then, the printing control unit 52 controls the fixation unit 34 to perform printing at the low productivity in a case where a transition to the power reduction mode is determined and controls the fixation unit 34 to perform printing at the normal productivity in a case where no transition to the power reduction mode is determined. The specified number of sheets corresponds to the value of the CPM of the above-described normal productivity, and, for example, in a case where the normal productivity is "CPM = 75 sheets/minute" (first speed), the specified number of sheets is 75 sheets. The storage unit 53 stores the specified number of sheets, the value of the CPM as the normal productivity, and the value of the CPM (second speed) as the low productivity. The storage of the above-described values, for example, is performed in advance by a manufacturer of the image forming apparatus in a manufacturing factory.

[0024] The display control unit 51 controls a display of information on the operation display unit 33 and causes the operation display unit 33 to display an operation screen that is used for a user to perform an operation input. In a case where a transition to the power reduction mode is determined by the printing control unit 52, the display control unit 51 causes the operation display unit 33 to display a message indicating that the supply of power is suppressed by the power supplier together with the operation screen. Fig. 6 is a diagram illustrating an exemplary display of the message. On the display 4 illustrated in Fig. 4, as illustrated in Fig. 6, the operation screen is displayed, and a message of "peak power is in the process of being suppressed by the power supplier" is displayed at center of the upper portion of the operation screen. Since the message illustrated in the figure is merely an example, another message may be displayed, the message may be displayed in the form of a symbol or a mark, or the message may be displayed by turning on an LED.

[0025] Next, the sequence of the processing performed by the image forming apparatus according to this embodiment will be described. First, the sequence of the processing performed when the image forming apparatus receives a power reduction command from the smart meter will be described with reference to Fig. 7. When the power reduction command is received from the smart meter through the wireless communication unit 41 (Yes in Step S1), the image forming apparatus sets up a power reduction flag by storing the power reduction flag having a value of "1" in the RAM 39 in Step S2. Next, the sequence of the processing performed when the image forming apparatus receives a power reduction cancelling command from the smart meter will be described with reference to Fig. 8. When the power reduction cancelling command is received from the smart meter through the wireless communication unit 41 (Yes in Step S10), the image forming apparatus releases the power reduction flag by setting the value of the power reduction flag stored in the RAM 39 to "0" in Step S 11.

[0026] Next, the sequence of processing performed in a case where the image forming apparatus performs printing as a copy operation or a printing operation will be described with reference to Fig. 9. In a case where there is a printing request such as a case in which there is an operation input instructing a copy through the operation display unit 33 or a case in which print instruction data is received from the information processing apparatus through the communication unit 44 (Yes in Step S20), the image forming apparatus refers to the power reduction flag stored in the RAM 39 and determines whether power reduction is requested from the power supplier by determining whether the value of the power reduction flag is "1" or "0" in Step S21. In a case where a positive determination result is acquired (Yes in Step S21), the image forming apparatus determines whether or not the requested number of prints is the specified number of sheets or more by comparing the requested number of prints that is designated in the printing request and the specified number of sheets that is stored in the storage unit 53 with each other in Step S22. In a case where the determination result is positive (Yes in Step S22), the image forming apparatus determines to transit into the power reduction mode, and, as illustrated in Fig. 6, displays a message indicating that the supply of power is suppressed by the power supplier on the operation display unit 33 in Step S23. Then, the image forming apparatus controls printing at the low productivity so as to be performed in accordance with the printing request in Step S24. Described in more detail, the image forming apparatus, as described above, performs printing while controlling the speed to "CPM = 65 sheets/minute". Thereafter, the image forming apparatus allows the message displayed on the operation display unit 33 in Step S23 not to be displayed.

[0027] On the other hand, in a case where the determination result of Step S21 is negative (No in Step S21), or the determination result of Step S22 is negative (No in Step S22), the image forming apparatus determines not to transit into the power reduction mode, and controls the printing at the normal productivity so as to be performed in accordance with the printing request in Step S25. Described in more detail, the image forming apparatus, as described above, performs printing while controlling the speed to "CPM = 75 sheets/minute".

[0028] Here, the advantages according to this embodiment will be described with reference to Figs. 10 to 11. Fig. 10 is a diagram illustrating an example of an actually measured waveform of the power of the image forming apparatus. The horizontal axis represents the time, and the vertical axis represents the power. A graph represented in an upper portion of the figure illustrates a waveform of the power when monochrome copy for A4 sheets is performed at "CPM = 75 sheets/minute" for 15 minutes or longer. A graph represented in a lower portion of the figure illustrates a waveform of the power when monochrome copy for A4 sheets is performed at "CPM = 65 sheets/minute" over 15 minutes or longer. In other words, the graph illustrated in the lower portion illustrates a result of printing at reduced productivity according to this embodiment. As a method of reducing the productivity, as described above, a method is used in which a paper passing interval is increased. As can be understood from Fig. 10, the waveforms of the power during a time period from 0 second to 200 seconds form similar curve in both cases. In addition, the averages of the amounts of power actually measured during a time period from 0 second to 200 seconds (referred to as average power) are about 2000 W in both cases. In the time period from 0 second to 200 seconds, when described with reference to Fig. 11, for example, in a case where monochrome copy for 75 sheets of the A4 paper size is performed, the copy is completed in about 60 seconds in the case of "CPM = 75 sheets/minute", and the copy is completed in about 70 seconds in the case of "CPM = 65 sheets/minute". Accordingly, in the case of "CPM = 65 sheets/minute", the time required for the copy is longer than that of the case of "CPM = 75 sheets/minute" by 10 seconds. The average amounts of power during this period are the same, and when areas formed by the time in the horizontal axis and the power in the vertical axis are considered, the power (power consumption) consumed in the case of "CPM = 75 sheets/ minute" is about 33 Wh (≈ 2000 W x 60 seconds / 60 seconds / 60 minutes), the power consumption in the case of "CPM = 65 sheets/ minute" is about 39 Wh (≈ 2000 W x 70 seconds / 60 seconds / 60 minutes), and, in a case where the CPM is reduced, although the productivity is low, the power consumption increases. In other words, in the image forming apparatus, in a case where the normal CPM, which is not in the power reduction mode, is 75 sheets/minute, and the requested number of prints is less than 75, the total amount of power consumption in a case where printing is performed at the normal speed of "CPM = 75 sheets/minute" without reducing the CPM to 65 sheets/minute is smaller than that in a case where printing is performed at the reduced speed. In addition, at time of 300 seconds later, the average power in the case of "CPM = 75 sheets/minute" is 1700 W (see HD1 in the figure), the average power in the case of "CPM = 65 sheets/minute" is 1400 W (see HD2 in the figure), and accordingly, by decreasing the CPM to 65 sheets/minute, the power consumption of about 300 W can be reduced on the average. Accordingly, by determining whether to perform printing at reduced productivity or perform printing without reducing the productivity in accordance with the requested number of prints and performing printing in accordance with the determination result, the reduction of the power consumption according to a command transmitted from the power supplier can be reliably realized just as the power supplier intended.

Second Embodiment

[0029] Next, an image forming apparatus, an image forming system and a method of forming an image according to a second embodiment will be described. Here, a portion that is common to the above-described first embodiment will be described with the same reference numeral used or will not be described.

[0030] According to the above-described first embodiment, in a case where the requested number of prints is the specified number of sheets or more, the image forming apparatus transits into the power reduction mode from the first sheet so as to perform printing. In this embodiment, until the number of paper sheets (referred to as the number of printed sheets) for which the printing has already been performed in accordance with a printing request, no transition to the power reduction mode is made, and printing is controlled at the normal productivity so as to be performed, and, in a case where the number of printed sheets reaches the specified number of sheets, a transition to the power reduction mode is made, and printing is controlled at the low productivity so as to be performed. Described in more detail, the printing control unit 52 of the image forming apparatus determines not to transit into the power reduction mode until the number of printed sheets reaches the specified number of sheets, and the fixation unit 34 is controlled so as to perform printing at the normal productivity, and, in a case where the number of printed sheets reaches the specified number of sheets, a transition to the power reduction mode is determined, and printing is controlled at the low productivity so as to be performed.

[0031] Next, the processing sequence in a case where printing is performed in accordance with a printing request by the image forming apparatus according to this embodiment will be described with reference to Fig. 12. Steps S20 to S22 are similar to those of the above-described first embodiment. In Step S30, the image forming apparatus, similarly to Step S25, performs control such that printing at the normal productivity is performed in accordance with a printing request. Thereafter, in Step S31, the image forming apparatus determines whether or not the number of printed sheets is the specified number of sheets or more by comparing the number (number of printed sheets) of paper sheets for which printing has already been performed in accordance with a printing request and the specified number of sheets that is stored in the storage unit 53 with each other. In a case where the determination result is negative (No in Step S31), the process is returned back to Step S30. On the other hand, in a case where the determination result of Step S31 is positive (Yes in Step S31), the process proceeds to Step S23. Steps S23 to S25 are similar to those of the above-described first embodiment.

[0032] As illustrated in the graph represented in the upper portion of Fig. 10, since the power consumption does not change even when the CPM is reduced during the time period from 0 second to 200 seconds, the image forming apparatus performs controls such that printing at the normal productivity is performed employing the above-described configuration, whereby an increase in the power consumption can be suppressed without degrading user convenience. Accordingly, a decrease in the power consumption according to a command transmitted from the power supplier can be reliably realized. On the other hand, when the time is 200 seconds later, the average power at the low productivity is reduced to 1400 W from the average power at the normal productivity of 1700 W, and accordingly, the image forming apparatus performs control such that printing at the low productivity is performed, whereby reduction of the power consumption according to a command transmitted from the power supplier can be effectively realized.

Third Embodiment

[0033] Next, an image forming apparatus according to a third embodiment will be described. Here, a portion that is common to the first or second embodiment described above will be described with the same reference numeral used or will not be described.

[0034] In each embodiment described above, although there is one type of low productivity that is reduced from the normal productivity in a power reduction mode, there is a plurality of types of low productivity in this embodiment. For example, CPM as a speed relating to first low productivity is set to 65 sheets/minute, and CPM as a speed relating to second low productivity is set to 55 sheets/minute. The normal productivity is similar to that of the above-described first embodiment. In such a case, a printing control unit 52 of the image forming apparatus determines to transit into the power reduction mode in a case where the requested number of prints is a first specified number of sheets or more, controls a fixation unit 34 such that printing at the first productivity is performed in a case where the requested number of prints is a first specified number of sheets or more and less than a second specified number of sheets, and controls the fixation unit 34 such that printing is performed at the second productivity in a case where the requested number of sheets is the second specified number of sheets or more. In addition, the first specified number of sheets is set to 50 sheets, and the second specified number of sheets is set to 100 sheets. These values, the value of the CPM at the first low productivity, the value of the CPM at the second low productivity, and the value of the CPM at the normal productivity are stored in a storage unit 53.

[0035] Next, the processing sequence in a case where printing is performed in accordance with a printing request by the image forming apparatus according to this embodiment will be described with reference to Fig. 13. Steps S20 and S21 are similar to those of the above-described first embodiment. In Step S40, the image forming apparatus determines whether or not the requested number of sheets is the first specified number of sheets or more by comparing the requested number of sheets that is designated in the printing request and the first specified number of sheets that is stored in the storage unit 53 with each other. In a case where the determination result is positive (Yes in Step S40), the image forming apparatus determines to transit into the power reduction mode, and, as illustrated in Fig. 6, displays a message indicating that the supply of power is suppressed by the power supplier on an operation display unit 33 in Step S23. Thereafter, the image forming apparatus determines whether or not the requested number of prints is the second specified number of sheets or more by comparing the requested number of sheets and the second specified number of sheets that is stored in the storage unit 53 with each other in Step S41. In a case where the determination result is negative (No in Step S41), the image forming apparatus performs control such that printing at the first low productivity is performed in accordance with the printing request in Step S42. Described in more detail, the image forming apparatus, as described above, performs control such that printing at the speed of "CPM = 65 sheets/minute" is performed. Thereafter, the image forming apparatus allows the message display displayed on the operation display unit 33 in Step S41 not to be displayed. On the other hand, in a case where the determination result of Step S41 is positive (Yes in Step S41), the image forming apparatus performs control such that printing at the second low productivity is performed in accordance with the printing request in Step S43. Described in more detail, the image forming apparatus, as described above, performs control such that printing is performed at a speed of "CPM = 55 sheets/minute". Thereafter, the image forming apparatus allows the message displayed on the operation display unit 33 in Step S23 not to be displayed. On the other hand, in a case where the determination result of Step S21 is negative (No in Step S21), or the determination result of Step S40 is negative (No in Step S40), the process proceeds to Step S25. Step S25 is similar to that of the above-described first embodiment.

[0036] According to the above-described configuration, by performing printing at reduced productivity in a stepped manner in accordance with the requested number of prints, the reduction of the power can be realized further efficiently while considering the user convenience.

Modified Examples

[0037] The present invention is not limited to the above-described embodiments and may be embodied by changing the constituent elements in a scope not departing from the concept thereof in implementation steps. In addition, various embodiments can be formed by appropriately combining a plurality of the constituent elements disclosed in the above-described embodiments. For example, several constituent elements may be eliminated from all the constituent elements represented in each embodiment. Furthermore, such constituent elements may be appropriately combined with another embodiment. In addition, various changes as represented below as examples can be made.

[0038] In the above-described embodiments, various programs that are performed by the image forming apparatus may be configured so as to be stored in a computer connected to a network such as the Internet and be provided by being downloaded through the network. In addition, the various programs may be configured so as to be recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD) in an installable format or an executable format and be provided as a computer program product.

[0039] In each embodiment described above, an example has been described in which the image forming apparatus is applied to an MFP that has a scanner function for scanning an image from an original, a copying function for performing printing based on the scanned image, and a printer function for performing printing based on the print instruction data. However, the image forming apparatus may be a copying machine that has a scanner function and a copying function or a printer that realizes a printer function. In addition, the image forming apparatus may further include a facsimile function.

[0040] In each embodiment described above, although the value of the specified number of sheets corresponds to the value of the CPM as the normal productivity, the present invention is not limited thereto. In addition, the value of the specified number of sheets may be stored in the storage unit 53 or updated in accordance with a request from the information processing apparatus through the communication unit 44 or may be stored or updated in accordance with a user operation input through the operation display unit 33. This is an example of a first setting unit.

[0041] In each embodiment described above, in order to determine whether or not to transit into the power reduction mode, although the specified number of sheets is used for being compared with a requested number of prints using the requested number of prints as the printing condition, the invention is not limited thereto, and a required time relating to printing and a specified time may be used. The required time relating to printing is calculated based on the requested number of prints and the normal productivity. The specified time is a value that is specified in advance for the required time relating to printing. In such a case, the printing control unit 52 determines to transit into the power reduction mode and controls the fixation unit 34 such that printing at the low productivity is performed in a case where the required time relating to printing according to a printing request is the specified time or longer. On the other hand, in a case where the required time is shorter than the specified time, the printing control unit 52 determines not to transit into the power reduction mode and controls the fixation unit 34 such that printing at the normal productivity is performed. The value of the specified time is set to a value such that average power of a case where printing at the low productivity is controlled so as to be performed continuously over the specified time is lower than that that of a case where printing is controlled to be performed at the normal productivity. In such a case, the storage unit 53 stores not the specified number of sheets but the specified time and the value of the normal productivity in advance. Fig. 14 is a flowchart illustrating the processing sequence of a case where an image forming apparatus according to this modified example performs printing in accordance with a printing request. Steps S20 and S21 are similar to those of the above-described first embodiment. In Step S50, the required time relating to printing of the requested number of sheets is calculated by using the requested number of prints that is designated in the printing request and the value of the normal productivity, for example, the value of "CPM = 75 sheets/minute", compares the required time and the specified time stored in the storage unit 53 with each other, and determines whether or not the required time relating to the printing is the specified time or longer. In a case where the determination result is positive (Yes in Step S50), the process proceeds to Step S23. On the other hand, in a case where the determination result is negative (No in Step S50), the process proceeds to Step S25. Steps S23 and S24 are similar to those of the above-described first embodiment.

[0042] By employing the above-described configuration, the reduction of power according to a command transmitted from the power supplier can be reliably realized as is intended.

[0043] In addition, the value of the specified time may be stored in the storage unit 53 or updated in accordance with a request from the information processing apparatus through the communication unit 44 or may be stored or updated in accordance with a user operation input through the operation display unit 33. This is an example of a second setting unit.

[0044] In each embodiment described above, as illustrated in the first embodiment with reference to Fig. 9, switching between enablement and disablement of the control function of determining whether or not to transit into the power reduction mode based on the printing condition and performing printing at changed productivity (speed) by using the image forming apparatus may be performed by a supervisor of the image forming apparatus. This switching, for example, may be performed in accordance with an operation input of a supervisor through the operation display unit 33 or may be performed by rewriting a value of a predetermined register that is included in the CPU 38. Also for the second embodiment (see Fig. 12), the third embodiment (see Fig. 13), and the modified example (see Fig. 14), similarly, switching between enablement and disablement of the control function of determining whether or not to transit into the power reduction mode based on the printing condition and performing printing at changed productivity may be performed by a supervisor of the image forming apparatus. This is an example of a switching unit.

[0045] In each embodiment described above, the value of the CPM as the low productivity is stored in the storage unit 53 in advance by the manufacturer of the image forming apparatus. However, the value of the CPM may be stored in the storage unit 53 or updated in accordance with a request from the information processing apparatus through the communication unit 44 or may be stored or updated in accordance with a user operation input through the operation display unit 33. This is an example of a third setting unit. As described above with reference to Fig. 10, although the power consumption in a time period from 0 second to 200 seconds does not change between the control of the normal productivity and the control of the low productivity, the power consumption is reduced as much as the amount of decrease in the value of the CPM in the control of the low productivity at 300 seconds later. Accordingly, the user sets the value of the CPM as the low productivity and stores the value of the CPM in the storage unit 53.

[0046] Fig. 15 is a diagram illustrating an example of a setting screen used for a user to perform an operation input of setting a CPM value (speed) as low productivity. In the example illustrated in the figure, the setting of the productivity can be divided into a case where full-color printing is performed for A4 sheets and a case where monochrome printing is performed for A4 sheets, and the values of the CPM as a plurality of types of low productivity and power consumption of a case where printing at each CPM is controlled to be performed are represented in contrast with the value of the CPM as the normal productivity. For example, in a case where color-copying for A4 sheets is performed, the normal productivity is 65 sheets/minute, and the power consumption is about 1800 W. In contrast to this, in a case where "CPM = 55 sheets/minute" is set as the low productivity, the power consumption is about 1500 W. Accordingly, in a case where printing at the low productivity is controlled to be performed, it is illustrated that, although the number of sheets that can be copied in one minute decreases by 10 sheets, compared to a case where printing at the normal productivity is performed, the power consumption can be reduced by 300 W. In addition, in a case where "CPM = 25 sheets/minute" is set as the low productivity, the power consumption is about 1000 W, and it is illustrated that, in a case where printing at the low productivity is controlled to be performed, although the number of sheets that can be copied in one minute decreases by 50 sheets, compared to a case where printing at the normal productivity is performed, the power consumption can be reduced by 800 W. As a user performs an operation input for selecting one value from among the values of the CPM as the low productivity of each case illustrated in the setting screen, the value of the CPM as the low productivity of each case is selected and is stored in the storage unit 53.

[0047] According to such a configuration, reduction of the power consumption can be realized in the range in which the user can cooperate.

[0048] In each embodiment described above, in a case where a transition to the power reduction mode is made, and printing at the low productivity is controlled to be performed, the user may be notified of the value of the CPM as the low productivity and the effect of the power reduction by the image forming apparatus. Described in more detail, the image forming apparatus displays the message illustrated in Fig. 16 as an example on the operation display unit 33. This is an example of a notification unit. In the example illustrated in the figure, a message is represented which includes an indication that a transition to the power reduction mode is made, the value of the CPM as the normal productivity, the value of the CPM as the low productivity, the amount of power reduction that is a difference between the power consumption of a case where printing at the normal productivity is controlled to be performed and the power consumption of a case where printing at the low productivity is controlled to be performed, and an effect of the power reduction that is a ratio of the amount of power reduction to the power consumption of a case where printing at the low productivity is controlled to be performed. Such a message may be displayed on the display 4 illustrated in Fig. 6 as an example, may be displayed in accordance with an operation input that is input by using the hardware keys 2, 3, 5 to 8, 12, and 15 to 21 illustrated in Fig. 4 as an example, or may be transmitted to the information processing apparatus through the communication unit 44 and be displayed on a display unit connected to the information processing apparatus.

[0049] According to such a configuration, the productivity of a case where the transition to the power reduction mode is made and the power reduction can be visually recognized in an easy manner.

[0050] According to the embodiments, reduction of the power consumption can be reliably realized in accordance with a command transmitted from an electric power supplier in consideration of the user convenience.

[0051] Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.

Claims

1. An image forming apparatus comprising:

an image forming unit (34) that forms an image on a recording medium based on designation of the image and image formation;

a communication unit (44) that communicates with an external apparatus;

a determining unit (32) that determines whether or not to reduce a speed at which the image forming unit (34) forms the image based on the designation, when the communication unit (41, 44) receives a power reduction command that requests to reduce power consumption; and

a control unit (31, 32) that allows the image forming unit (34) to form the image on the recording medium at a second speed lower than a first speed that is determined in advance, when the determining unit (32) determines the speed to reduce.

2. The image forming apparatus according to claim 1,
wherein
the designation is a first number of sheets that is the number of sheets of target recording media on which the image is formed, and
the determining unit (32) determines whether or not to reduce the speed in accordance with the first number of sheets that is designated by the image forming instruction, when the communication unit (41, 44) receives the power reduction command.

3. The image forming apparatus according to claim 2, wherein
the determining unit (32) determines whether or not to reduce the speed by determining whether or not the first number of sheets is a specified number of sheets or more, when the communication unit (41, 44) receives the power reduction command.

4. The image forming apparatus according to claim 2, wherein,
when the communication unit (41, 44) receives the power reduction command, and the first number of sheets is the specified number of sheets or more, the determining unit (32)
determines not to reduce the speed until the second number of sheets, which is a number of the recording media on which the images are already formed by the image forming unit (34), based on the and
determines to reduce the speed, when the second number of sheets reaches the specified number of sheets, and
wherein the control unit (31, 32)
allows the image forming unit (34) to form the images on the recording media at the first speed, when the determining unit (32) determines the speed not to be reduced and
allows the image forming unit (34) to form the images on the recording media at the second speed, when the determining unit (32) determines the speed to be reduced.

5. The image forming apparatus according to any one of claims 2 to 4, further comprising:

a storage unit (39, 40, 42) that stores the specified number of sheets therein; and

a first setting unit (32) that sets a value of the specified number of sheets in the storage unit (39, 40, 42).

6. The image forming apparatus according to claim 2,
wherein,
when the power reduction command is received by the communication unit (41, 44), the determining unit (32)
determines to reduce the speed to a third speed that is lower than the first speed when the first number of sheets is the first specified number of sheets or more and less than the second specified number of sheets, and
determines to reduce the speed to a fourth speed that is lower than the third speed when the first number of sheets is the second specified number of sheets or more; and
the control unit (31, 32)
allows the image forming unit (34) to form the images on the recording media at the third speed when the speed is determined to be reduced to the third speed, and
allows the image forming unit (34) to form the images on the recording media at the fourth speed when the speed is determined to be reduced to the fourth speed.

7. The image forming apparatus according to claim 2, wherein
the determining unit (32), when the power reduction command is received by the communication unit (41, 44), determines whether or not to reduce the speed
by calculating a time relating to the formation of the image using the first number of sheets and the speed and
by determining whether or not the time is a specified time or longer.

8. The image forming apparatus according to claim 7, further comprising:

a storage unit (39, 40, 42) that stores the specified time therein; and

a second setting unit (32) that sets a value of the specified time in the storage unit (39, 40, 42).

9. The image forming apparatus according to any one of claims 1 to 5, further comprising:

a third setting unit (32) that sets a value of the second speed.

10. The image forming apparatus according to any one of claims 1 to 9, further comprising:

a switching unit (33) that switches between enablement and disablement of functions of the determining unit (32) and the control unit (31, 32).

11. The image forming apparatus according to any one of claims 1 to 5, further comprising:

a notification unit (33, 41) that notifies an amount of power reduction that is calculated based on a value of the second speed, the power consumption relating to the image formation at the first speed, and the power consumption relating to image formation at the second speed.

12. An image forming system in which an image forming apparatus and an external apparatus managing electric power of the image forming apparatus are connected to each other,
wherein
the external apparatus comprises
a transmission unit that transmits a power reduction command requesting to reduce power consumption to the image forming apparatus; and
the image forming apparatus comprises:

an image forming unit (34) that forms an image on a recording medium based on designation of the image and image formation;

a communication unit (41, 44) that communicates with the external apparatus;

a determining unit (32) that determines whether or not to reduce a speed at which the image forming unit (34) forms the image based on the designation, when the communication unit (41, 44) receives the power reduction command; and

a control unit (31, 32) that allows the image forming unit (34) to form the image on the recording medium at a second speed that is lower than a first speed that is determined in advance, when the determining unit (32) determines the speed is to be reduced.

13. A method of forming an image that is performed by an image forming apparatus including an image forming unit (34) that forms an image on a recording medium, a communication unit (41, 44) that communicates with an external apparatus, a determining unit (32), and a control unit (31, 32), based on designation of the image and image formation, the method comprising:

determining whether or not to reduce a speed at which the image forming unit (34) forms the image based on the designation determined by the determining unit (32), when a power reduction command requesting to reduce power consumption is received by the communication unit (41, 44); and

controlling to allow the image forming unit (34) to form the image on the recording medium at a second speed that is lower than a first speed that is set in advance, when the speed is determined to be reduced by the determining unit (32).

Drawing