JP5023234B2 - Image forming apparatus and power supply control method thereof - Google Patents

Description

The present invention relates to an image forming apparatus such as a laser printer, a copier, a FAX, and a multifunction peripheral having a main power supply device that supplies DC power and an auxiliary power supply device that supplies DC power that can be stored, and a power supply control method thereof. .

In recent years, copying machines, printers, facsimiles, and multi-function machines that combine these using an electrophotographic process have become multifunctional, and accordingly, the structure is complicated and the maximum power consumption tends to increase. In order to reduce the factors of the image forming device itself and the waiting time of the operator, such as the waiting time until the fixing device rises and the temporary interruption of the operation due to the fixing temperature drop during the printing or copying operation, the power supplied to the fixing heater Tends to increase.

On the other hand, since there is a limit to the power that can be supplied from a normal power supply line, this is a major limitation in designing the equipment. Regarding leveling of load power, for example, Patent Document 1
Is provided with means for monitoring the supply power of the main power supply, the auxiliary power supply is charged when the supply power of the main power supply is less than a preset value, and the auxiliary power is supplied when the supply power of the main power supply is greater than a preset value. There has been disclosed a technique for leveling power that changes sharply in a relatively short time by discharging energy stored in a power source.

Further, Patent Document 2 predicts the power consumption, and when the predicted power consumption exceeds the power that can be supplied from the main power supply, power is supplied to some loads from the auxiliary power supply, and the maximum power that can be supplied from the power supply line. A power supply device that does not exceed the above is disclosed.

However, in the technique described in Patent Document 2, since the two types of power supply sources are switched in the power supply to a part of the load, if there is a voltage difference between the powers supplied by the two types of power supply sources, the power supply source Voltage fluctuation occurs during switching. This may affect various operations in the image forming apparatus. In particular, in an image forming apparatus having a color image creation function for forming images of a plurality of colors, there is a concern about occurrence of abnormal images such as color misregistration due to voltage fluctuations at the time of switching. This point is not considered in the invention described in Patent Document 1.

The present invention has been made in view of such a state of the art, and an object thereof is to suppress the occurrence of an abnormal image such as a color shift due to voltage fluctuation during an image forming operation.

In order to achieve the above object, the present invention has a load supplied with DC power using either a main power supply that supplies DC power or an auxiliary power supply that can store DC power as a DC power supply source. In the image forming apparatus that forms an image based on the input job, when the DC power supply source switching condition is reached during the image forming operation and while the DC power is being supplied from the auxiliary power supply to the load, time and to the end of the required power or processing jobs until the end of the job in the remaining power of the auxiliary power supply, based on, or switches the DC power source at the time of the job end to the main power supply, Control means for determining whether to perform an image forming interruption switching processing operation for resuming the image forming operation after interrupting the image forming operation and switching the DC power supply source to the main power supply device is provided.

According to the present invention, it is possible to suppress the occurrence of abnormal images such as color misregistration due to voltage fluctuations during an image forming operation.

1 is a diagram illustrating an outline of a system configuration of a full-color digital multifunction peripheral according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic configuration of a color printer of the copying machine of FIG. 1. FIG. 2 is a block diagram illustrating a main part of a control unit that controls operation of the copying machine of FIG. 1. FIG. 2 is a block diagram showing a configuration of a power supply system of the copying machine of FIG. 1. It is a flowchart which shows an example of the control procedure of charging / discharging control of the capacitor which is the auxiliary power supply of a control part. FIG. 6 shows a control for interrupting the image forming operation when the DC power supply source switching condition is reached during the image forming operation and supplying the DC power from the auxiliary power supply device, and restarting the operation after the DC power supply source switching process. It is a flowchart which shows a procedure. It is a flowchart which shows the control procedure which shows the control procedure which stops a part of load when the electrical storage amount of an auxiliary power supply device becomes below a preset value during image formation operation and supplying DC power from the auxiliary power supply device. . When the DC power supply switching condition is reached during the image forming operation and during the supply of DC power from the auxiliary power supply, the DC power depends on the required power until the end of the job being processed and the remaining power of the auxiliary power supply at that time. It is a flowchart which shows the control procedure which determines the switching timing of a supply source.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a full-color digital multi-function peripheral (multi-function copier--hereinafter, referred to as an embodiment of the present invention).
1 is a diagram showing an outline of a system configuration of MF1 (hereinafter simply referred to as a copying machine). In FIG. 1, the copying machine MF <b> 1 includes units of an automatic document feeder (ADF) 120, an operation unit (operation board) 10, a color scanner 100, and a color printer 200. The operation board 10 and the color scanner 100 with the ADF 120 are units that can be separated from the printer 200. The color scanner 100 includes a control board having a power device driver, a sensor input, and a controller, and an engine controller. Communication is performed directly or indirectly, and the timing is controlled to read a document image. This system is connected to a personal computer PC and a private branch exchange PBX.

FIG. 2 is a diagram showing a schematic configuration of the color printer 200 of the copying machine MF1. In the figure, a color printer 200 is an electrophotographic so-called laser printer that performs optical writing. The laser printer 200 includes four sets of toner image forming units a and b for forming images of magenta (M), cyan (C), yellow (Y), and black (black: K) colors.
, C, d are arranged in this order along the moving direction of the first transfer belt 208 (the direction of arrow A in the figure). That is, it is a four-drum type (tandem type) full-color image forming apparatus.

A neutralizing device, a cleaning device, a charging device 202 and a developing device 204 are arranged on the outer periphery of the photosensitive member 201 that is rotatably supported and rotates in the direction of the arrow. A space for storing optical information emitted from the exposure device 203 is secured between the charging device 202 and the developing device 204. There are four (a, b, c, d) photoconductors 201, but the image forming component configuration provided around each is the same. However, the color of the color material (toner) handled by the developing device 204 is different. A part of each photoconductor 201 (four) is in contact with the first transfer belt 208. A belt-like photoreceptor can also be employed.

The first transfer belt 208 is supported and stretched between a rotating support roller and a driving roller so as to be movable in the direction of the arrow. On the back side (inside the loop), the first transfer roller 216 is in the vicinity of the photoreceptor 201. Has been deployed. A cleaning device 217 for the first transfer belt 208 is disposed outside the belt loop. The cleaning device 217 includes the first transfer belt 208.
After the toner image is transferred to the transfer paper (paper) or the second transfer belt 215, unnecessary toner remaining on the surface is wiped off. The exposure device 203 uses a known laser method to irradiate the uniformly charged surface of the photoconductor 201 with optical information corresponding to full-color image formation.
A latent image is formed on the 01 surface. An exposure apparatus including an LED array and an image forming unit may be employed instead of the laser scanning apparatus (for example, a laser diode, a polygon mirror, and a scanning optical system associated therewith).

In FIG. 2, a second transfer belt 215 is provided on the right side of the first transfer belt 208. The first transfer belt 208 and the second transfer belt 215 come into contact with each other to form a predetermined transfer nip. The second transfer belt 215 is supported and stretched between the support roller and the drive roller so as to be movable in the direction of arrow B, and on the back side (inside the loop), the second transfer means 2
18 is arranged. A cleaning device 219, a charger 231 and the like for the second transfer belt 215 are disposed outside the belt loop. The cleaning device 219 wipes off the remaining unnecessary toner after transferring the toner onto the paper. Transfer sheets (sheets) are stored in sheet feeding cassettes 209 and 210 at the bottom of the figure, and the uppermost sheet is conveyed by sheet feeding rollers one by one to a registration roller 233 through a plurality of sheet guides. Also, the second transfer belt 215
Above the fixing unit 214, a fixing device 214 having a fixing roller 230, a paper discharge guide 224, and a paper discharge roller 2.
25, a paper discharge stack 226 is arranged. A storage unit 227 for storing replenishment toner is provided above the first transfer belt 208 and below the paper discharge stack 226. There are four toner colors, magenta, cyan, yellow, and black, which are in the form of cartridges. The toner stored in these cartridges is appropriately replenished to the corresponding color developing device 204 by a powder pump or the like. Further, a control unit 20 including a control board is disposed above the storage unit 227.

  Here, the operation of each unit during duplex printing will be described. First, image formation by the photoconductor 201 is performed.

That is, by the operation of the exposure device 203, light from an LD light source (not shown) passes through an optical component (not shown), and among the photoconductors 201 uniformly charged by the charging device 202, the photoconductor of the image forming unit a. A latent image corresponding to the writing information (information corresponding to the color) is formed. The latent image on the photoconductor 201 is developed by the developing device 204, and a visible image with toner is formed and held on the surface of the photoconductor 201. This toner image is transferred onto the surface of the first transfer belt 208 that moves in synchronization with the photoreceptor 201 by the first transfer means. After the remaining toner is cleaned by the cleaning device, the surface of the photoconductor 201 is discharged by the charge removing device to prepare for the next image forming cycle. The first transfer belt 208 carries the toner image transferred on the surface and moves in the arrow A direction. A latent image corresponding to another color is also written on the photoconductor 201 of the image forming unit b, and developed with a corresponding color toner to become a visible image. This image is overlaid on the visible image of the previous color already on the first transfer belt 208, and finally four colors are overlaid. In some cases, only monochrome black is formed. At this time, the second transfer belt 215 is moved in the direction of arrow B in synchronization with this, and the image formed on the surface of the first transfer belt 208 is transferred to the surface of the second transfer belt 215 by the action of the second transfer means 118. The The first and second transfer belts 208 and 215 move while images are formed on the respective photosensitive members 201 of the four image forming units a to d in a so-called tandem format,
Since the image is advanced, the time can be shortened. When the first transfer belt 208 moves to a predetermined position, a toner image to be created on another side of the paper is formed again by the photoconductor 201 in the process described above, and paper feeding is started. Any paper cassette 121,1
The uppermost sheet in the sheet 22 is pulled out and conveyed to the registration roller 233. The sheet is fed between the first transfer belt 208 and the second transfer belt 215 by the registration roller 233 in time with the leading edge of the image on the first transfer belt 208, and the surface of the first transfer belt 208 is placed on one side. The toner image is transferred by the action of the second transfer means 117. Further, the sheet is conveyed upward, and the toner image on the surface of the second transfer belt 215 is transferred to the other surface by the charger 231. At the time of transfer, the sheet is conveyed at a timing so that the position of the image is normal.

The paper having the toner images transferred on both sides in this way is sent to the fixing device 214, and the toner images (both sides) on the paper are melted and fixed at one time. Are discharged to the paper discharge stack 226. As shown in FIG.
26, the surface (page) to be transferred to the paper later, that is, the surface directly transferred from the first transfer belt 208 to the paper in the double-sided image is the lower surface and is placed on the paper discharge stack 226. Therefore, in order to align the pages, the second page image is created first, the toner image is held on the second transfer belt 215, and the first page image is directly transferred from the first transfer belt 208 to the sheet. Transcript.

The image directly transferred from the first transfer belt 208 to the paper is a normal image on the surface of the photoconductor 201, and the toner image transferred from the second transfer belt 215 to the paper is a reverse image (mirror image) on the surface of the photoconductor 201. It is exposed to become. Such image forming order for page alignment and image processing for switching between normal and reverse images (mirror images) are also performed by read / write control of image data with respect to the memory on the controller 501. After the transfer from the second transfer belt 215 to the paper, a cleaning device 219 including a brush roller, a collection roller, a blade, and the like is used for the second transfer belt 215.
Remove unnecessary toner and paper dust remaining on the surface.

In FIG. 2, the brush roller of the cleaning device for the second transfer belt 215 is replaced with the second transfer belt 2.
15 is away from the surface of the brush 15, but the brush roller can swing around the fulcrum,
The transfer belt 215 can be brought into contact with and separated from the surface. Before the transfer onto the paper, the second transfer belt 215 is separated when carrying a toner image, and when cleaning is required, it is swung in the counterclockwise direction in FIG. The removed unnecessary toner is collected in a toner storage unit. The image forming process in the duplex printing mode in which the “duplex transfer mode” is set has been described above. In the case of duplex printing, printing is always performed by this image forming process.

In the case of single-sided printing, there are two types of "single-sided transfer mode by the second transfer belt 215" and "single-sided transfer mode by the first transfer belt 208", and the single-sided transfer mode using the former second transfer belt 215 is set. In this case, a visible image formed in three colors, four colors, or monochromatic black on the first transfer belt 208 is transferred to the second transfer belt 215 and transferred to one side of the paper. There is no image transfer on the other side of the paper. In this case, there is a print screen on the upper surface of the printed paper discharged to the paper discharge stack 226. When the single-sided transfer mode using the latter first transfer belt 208 is set, a visible image formed in three colors, four colors, or single color black is transferred to the second transfer belt 215 on the first transfer belt 208. Instead, it is transferred to one side of the paper. There is no image transfer on the other side of the paper. In this case, there is a print screen on the lower surface of the printed paper discharged to the paper discharge stack 226.

FIG. 3 is a block diagram showing the main part of the control unit that controls the operation of the copying machine MF1 according to the present embodiment. The operation of the copying machine MF1 in the present embodiment to be described later is realized by the control unit 20. The control unit 20 stores a CPU 21, a ROM 22 that stores a program for operating the CPU 21, a RAM 23 that functions as a work memory when the CPU 21 executes the program, stores adjustment values such as control and timing, and is turned off. Even in this case, the nonvolatile RAM 24 that can hold the data and the load 47a, 47b, 47c in the apparatus shown in FIG. / O control unit 25. The load 47a is a + 5V system and the load 47b.
Is a + 24V system (1), and the load 47c is a + 24V system (2). CPU is the ROM 2
2. Using the RAM 23, the nonvolatile RAM 24, and the I / O control unit 25, an original reading operation and an image forming operation for outputting the read original image are executed.

FIG. 4 is a block diagram showing the configuration of the power supply system of the copying machine MF1 according to the present embodiment.
The power supply system includes an AC line 41, a main power supply SW40, a main power supply 42, a capacitor charger 43, a capacitor 44, a capacitor converter 46, a switching circuit 48, and the loads 47a and 47b.
, 47c. In the power supply system having such a configuration, AC power supplied from the AC line 41 via the main power SW40 is converted into DC power by the AC / DC converter 42a included in the main power supply 42, and some are directly + 24V and + 5V. Each load (1) 47b of the system,
47a is supplied as a power source. The AC power is also input to the capacitor charger 43 and used for charging the capacitor 44. The charging voltage is detected by the voltage detection unit 45. A capacitor 44 (hereinafter also referred to as an auxiliary power source) as an auxiliary power source is configured by a large capacity capacitor such as an electric double layer capacitor. Although various selections can be made in addition to the electric double layer capacitor, in this embodiment, an electric double layer capacitor that can be charged and discharged in a short time and has a long life is used.

As a characteristic of the electric double layer capacitor, since the terminal voltage of the electric double layer capacitor becomes lower as it is discharged, the output voltage is made constant by disposing the capacitor converter 46 at the subsequent stage of the capacitor 44. As the capacitor converter 46,
Any one of a boost converter, a step-down converter, and a buck-boost converter is used according to the charging voltage of the capacitor 44 and the lower limit voltage specification. The switching circuit 48 is a + 24V power source generated by the AC / DC converter 42a based on the AC power source supplied from the AC line 41, and +24 generated through the capacitor converter 46 from the energy stored in the capacitor 44.
The V power supply is switched according to the control by the control unit 20 and supplied to the + 24V system load (2) 47c.

The control unit 20 shown in FIG. 3 also controls the entire copying machine MF1, and sequentially operates the loads 47a, 47b, and 47c according to each operation mode. The control unit 20 also controls charging / discharging of the capacitor 44. The capacitor converter 46 generates energy from the energy accumulated in the capacitor 44 during the startup of the apparatus and for a predetermined time after the startup. The switching circuit 48 is switched and operated so as to supply the + 24V power thus supplied to the + 24V system load (2) 47c. At this time, the margin generated with respect to the power supplied from the AC line 41 controls the fixing heater driving circuit 42 b to increase the amount of power supplied to the fixing heating device 49.

FIG. 5 is a flowchart illustrating an example of a control procedure of charge / discharge control of the capacitor 44 that is an auxiliary power source of the control unit 20.
In the figure, first, in step S1, the state of the apparatus is grasped. That is, the main power source S
Immediately after W40 is turned on or at the time of return from the off mode, it is checked whether or not the fixing reload operation is to be executed. If it is determined that it is necessary, the switching circuit 48 causes the + 24V system load in step S2. (2) The power supply to 47c is switched from the energy stored in the capacitor 44 to the + 24V power source produced through the capacitor converter 46. In step S3, the power that can be supplied to the fixing heating device 49 is increased, and the fixing reload operation is started (step S4).

When the completion of the fixing reload operation is confirmed in step S5, it is determined whether or not there is a print instruction from the operator in step S6. When there is a print instruction and it is necessary to switch the fixing supply power to the power during fixing reloading, the fixing supply power is switched to the power required at the start of printing in step S7, and the + 24V load load (2) by the auxiliary power supply 4
The printing operation is started with the power supplied to 7c (step S8). After starting the printing operation, a timer is started (step S9), and when it is confirmed that a predetermined time has passed (step S10), the fixing supply power is switched to the supply power for normal printing (step S11), and the + 24V system load is continued. (2) The power supply to 47c is switched to the +24 power supply generated by the AC / DC converter 42a as the main power supply, and the capacitor converter 46 stops (step S12).
). After the fixing reload, if there is no print instruction in step S6, the DC power supply source is switched at this timing, and the auxiliary power supply is stopped (steps S11 and S12). Note that the switching condition determination in step 10 may be the remaining amount of the power storage device (capacitor 44) or the amount of output power from the power storage device.

In the control procedure of FIG. 5, the first means does not reach the switching condition (step S
10) Corresponding to switching to the next step by executing switching at a timing when image formation is not performed, such as between sheets, without performing an immediate switching process during the image forming operation.

In an apparatus with a high printing speed, an image forming operation is continuously performed during a job, and an image forming operation is also performed between sheets, and it is not possible to cope with a case where a switching condition is reached. FIG. 6 shows that the image forming operation is interrupted when the DC power supply source switching condition is reached during the image forming operation and the DC power is being supplied from the auxiliary power supply device, and the operation is resumed after the DC power supply source switching process. It is a flowchart which shows a control procedure, and respond | corresponds to control of a said 2nd means.

That is, when there is an instruction to start power supply from the auxiliary power supply (step S41), power supply from the auxiliary power supply is started (step S42), and the power supply source to a predetermined load is switched from the main power supply to the auxiliary power supply ( Step S43). Whether or not the switching condition of the auxiliary power supply is reached during the power supply from the auxiliary power supply is monitored (step S44), and if the switching condition is reached, it is determined whether the system is in the image forming process (step S44). S45). When the image forming process is in progress, the image forming operation is interrupted (step S46), and the power supply source is switched from the auxiliary power source to the main power source (step S47). After completion of the switching process, the image forming operation is resumed and the power supply from the auxiliary power supply is stopped (step S48).

This procedure is a DC that converts power from the auxiliary power source (capacitor 44) into predetermined DC power.
-Since the input voltage range that can be output by the DC converter (capacitor converter 46) is limited, the time during which the auxiliary power 44 can be supplied may be limited. In that case, in order to maintain the power supply from the auxiliary power supply 44 in consideration of the switching processing time, it is necessary to provide a margin for the power supply source switching condition. The capacitor voltage that becomes the switching condition is Vsw [V].
When the output possible lower limit voltage of the DC-DC converter 44 is Vddcmin [V], the DC power consumption is Wdc [W], and the capacitor capacity is C [F], D is reached after reaching the switching condition.
The time t10 [s] until the C-DC converter 44 becomes unable to output is
t10 = C {(Vsw) 2- (Vddcmin) 2} / 2Wdc [s]
It becomes. Here, the image quality adjustment control time is 10 [s], the capacitor capacity is 43 [F], DC−
Assuming that the output lower limit voltage of the DC converter 44 is 18 [V] and the DC power consumption is 240 [W],
Vsw ≧ 20.87 [V]
Must be set to

In the third means, when the DC power supply source switching condition is reached during the image forming operation and while the DC power is being supplied from the auxiliary power supply device, the DC is performed after the end of the primary transfer and before the start of the next writing.
The power supply source is switched. On the other hand, the power supply source is switched from the main power source to the auxiliary power source in step S43. However, when switching is performed immediately after the primary transfer, it is good if the switching process can be executed before starting image formation on the next page. If the paper interval is short and the switching process is not in time, or if the timing for interrupting the image formation in color printing does not occur, the image formation interruption process is required. Therefore, in such a case, step S in the flowchart of FIG.
The image forming interruption process 46 is performed immediately after the completion of the primary transfer. As a result, the interruption time can be shortened, and the reduction in productivity can be suppressed.

The fourth means performs the image forming interruption process of step S46 in the flowchart of FIG.
This corresponds to the processing performed immediately after the end of the next transfer. Thereby, the interruption time can be shortened and the occurrence of an abnormal image can be prevented.

FIG. 7 shows a control procedure showing a control procedure for stopping a part of the load when the power storage amount of the auxiliary power supply device becomes equal to or less than a preset value during the image forming operation and the supply of DC power from the auxiliary power supply device. It is a flowchart. In this control procedure, when there is an instruction to start power supply from the auxiliary power supply (capacitor) 44 (step S51), power supply from the auxiliary power supply 44 is started (step S52), and a power supply source to a predetermined load is turned on. The main power source 42 is switched to the auxiliary power source 44 (step S53). When the amount of power stored in the auxiliary power supply 44 decreases during power supply from the auxiliary power supply 44 and falls below a predetermined value (step S54), and the apparatus is performing an image forming operation (step S55), power supply is performed. The internal load is stopped (step S56). By stopping part of the load, the power supply time from the auxiliary power supply 44 can be extended. When the power supply termination condition from the auxiliary power supply 44 is reached (step S57), the power supply source is changed to the auxiliary power supply 44 as usual.
Is switched to the main power source 42, and the operation of the stopped load is resumed. At the time of switching, the occurrence of an abnormal image can be prevented by executing the process of step S44 in FIG.

  The load that is stopped in step S56 is preferably a load that does not cause a delay in the printing operation.

For example, when there is a margin in the in-machine temperature, the cooling fan is temporarily stopped. In addition, in an apparatus in which image reading by the scanner and image formation by the printer unit are asynchronous, reading may precede the image formation. In this case, there is no delay in the system even if the reading operation is interrupted. The processing procedure of FIG. 7 corresponds to the control content of the sixth means.

In addition, in the case of multiple color image formation, for example, color image formation, instead of single color image formation,
In step S44 in the flowchart of FIG. 6 and step S55 in the flowchart of FIG. In black mode printing or single color printing such as yellow, color shift due to voltage fluctuation does not occur, so switching operation is performed even during image formation, and only in color mode that overlays multiple colors and reproduces color By controlling to execute the interruption process or the like, it is possible to prevent the interruption of the image forming operation depending on the mode. That is, in the laser printer 200 having a color printing function, a DC brushless motor is often used for driving the photosensitive member 201. The motor hardly causes rotation unevenness due to power supply voltage fluctuation. However, the color misregistration during color printing may result in an abnormal image even if a misregistration of several hundreds of um occurs. By controlling in this way, the color misregistration of the color image can be minimized. This processing procedure corresponds to the control of the fifth means.

FIG. 8 shows that when the DC power supply switching condition is reached during the image forming operation and while the DC power is being supplied from the auxiliary power supply, it depends on the required power until the job being processed at that time and the remaining power of the auxiliary power supply. 5 is a flowchart showing a control procedure for determining the switching timing of the DC power supply source. In this control procedure, when there is an instruction to start power supply from the auxiliary power supply 44 (step S).
61) The power supply from the auxiliary power supply 44 is started (step S62), and the power supply source to the predetermined load is switched from the main power supply 42 to the auxiliary power supply 44 (step S63). When the switching condition is reached during the power supply from the auxiliary power supply 44 (step S64) and the image forming operation is being performed (
In step 65), the amount of power that needs to be supplied from the auxiliary power supply 44 until the end of the job is calculated (
In step S66, the result is compared with the amount of electricity stored (step S67). If the amount of electricity stored is equal to or greater than the amount of power, the image forming operation is continued until the end of the job, and the switching process is executed after the end of the job (step S68). . If the stored power is less than or equal to the amount of power, the power supply source is switched from the auxiliary power source 44 to the main power source 42 to execute processing. At the time of switching, the occurrence of an abnormal image can be prevented by executing the process of step S44 in FIG. Further, when it is difficult to calculate the power in step S66, it is possible to make a determination based on the time until the end of the job. Regarding the amount of stored electricity, it is also possible to determine the stored voltage using the output power in addition to the stored amount. The control procedure of FIG. 8 corresponds to the control of the seventh means. That is, while supplying DC power from the auxiliary power supply 44, D
The conditions for switching the C power supply source are often determined by the capacity of the auxiliary power supply 44 or the output time from the auxiliary power supply 44. When the switching condition of the DC power supply source is the output time, the operation as a system is not affected even if the switching timing is delayed if there is a margin in the charged amount.

When the job is completed while DC power is being supplied from the auxiliary power supply 44 to the load (2) 47c, an immediate switching process is executed. As a result, the occurrence of switching processing during the image forming operation can be prevented. The processing in FIG. 8 corresponds to the control of the eighth means.
As described above, according to the present embodiment,
1) Since control is performed so as not to switch the DC power supply source during the image forming operation, it is possible to suppress the occurrence of abnormal images due to voltage fluctuations that occur at the time of switching.
2) When the switching condition is reached during the job, the image forming operation is interrupted and the switching control is performed, so that the occurrence of an abnormal image due to the voltage fluctuation occurring at the time of switching can be suppressed.
3) Since the switching process is performed after the completion of the primary transfer and before the next writing, the occurrence probability of the abnormal image can be reduced, and the interruption time can be reduced even when the interruption process is necessary.
4) Since the switching process is performed after the completion of the secondary transfer and before the next writing, the probability of occurrence of an abnormal image can be further reduced as compared with the case where the switching process is performed after the completion of the primary transfer. However, the interruption time is longer than when the switching process is performed after the primary transfer.
5) Since the switching operation timing is changed depending on the mode during the image forming operation, it is possible to suppress the occurrence of an abnormal image and at the same time suppress the decrease in productivity due to the interruption.
6) Since the power supply to the load that is preceded by the operation or to the load that does not affect the productivity is interrupted, the output from the power storage device can be reduced and the frequency of the switching process during the image forming operation can be suppressed.
7) Since the switching process is performed after the end of the job when there is a margin in the charged amount, the occurrence of an abnormal image can be suppressed.
8) Since the switching process is performed when the job being executed is completed regardless of the amount of stored electricity, it is possible to suppress the occurrence of abnormal images and a decrease in productivity.
There are effects such as.

20 control unit 21 CPU
22 ROM
23 RAM
24 Nonvolatile RAM
40 Main power switch
41 AC line 42 Main power supply 44 Capacitor (auxiliary power supply)
46 Capacitor converter 48 Switching circuit MF1 Copy machine

JP 2002-299588 A JP 2004-236492 A

Claims (3)

An image is formed based on an input job having a load to which DC power is supplied using either one of a main power supply that supplies DC power and an auxiliary power supply that can store DC power as a DC power supply. In an image forming apparatus that performs
When the DC power supply switching condition is reached during the image forming operation and while the DC power is being supplied from the auxiliary power supply to the load, the required power until the end of the job being processed or the end of the job being processed time, a remaining power of the auxiliary power supply, based on, or switches the DC power source at the time of the job end to the main power supply was switched to interrupt the image forming operation of the DC power supply to the main power supply An image forming apparatus comprising: a control unit that determines whether to perform an image forming interruption switching processing operation that restarts an image forming operation later. The image forming apparatus according to claim 1, wherein the image formation interruption switching processing operation is performed after the completion of the primary transfer and before the start of the next writing . The image forming apparatus according to claim 1, wherein the image formation interruption switching processing operation is performed after the end of the secondary transfer and before the start of the next writing .

Images