JP2007036810A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a prescribed function during executing until the end of the execution, even when a fault is generated in a power supply apparatus during the execution of the function in an image forming apparatus having multifunctions. <P>SOLUTION: The image forming apparatus is provided with means, such as a plotter engine and a scanner engine 2 for executing jobs and a plurality of power supply means, such as controlling power supply modules 11, 12 connected in parallel to supply power to the job execution means. Furthermore, the image forming apparatus is provided with a controlling output abnormality detection module 20 for detecting abnormality in the power supply means and a means for deciding whether the job execution means itself is executing the job on the basis of the detection result of the module 20. When there is no execution of job is decided, power supply to the job execution means is stopped, or the reduction or the like of an operation clock of the job execution means is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a plurality of functions such as a copy function, a scanner function, a printer function, and a facsimile function.

  In recent years, composite image forming apparatuses in which a plurality of functions such as a copy function, a scanner function, a printer function, and a facsimile function are provided in one image forming apparatus have been widely used. Such an image forming apparatus is configured by a plurality of control boards on which a control circuit including a CPU is mounted in order to be able to execute each function independently. In order to supply power to these control boards, a plurality of such image forming apparatuses are provided. The power system of the output system is provided.

  Since the power supply apparatus is a major source for operating the image forming apparatus, and failure of the power supply apparatus causes the worst situation that disables the use of the image forming apparatus, various measures have been conventionally taken as countermeasures against power supply failure.

  One of the inventions is a main control unit that controls the entire image formation such as an image forming process, and a copy unit, a scanner unit, a printer unit, a facsimile unit, etc. corresponding to a copy function, a scanner function, a printer function, a facsimile function, etc. In the case of a failure of the power supply unit of the main control unit, the priority order of the main control unit as the first order and the sub control unit as the second order or less is determined. In this invention, power is supplied, and at that time, for example, the power supply of the facsimile unit having a low priority is stopped (see Patent Document 1).

According to the above-described invention, when a failure occurs in the power supply of the main control unit, the main control unit is operated by sacrificing the operation of the sub-control unit having a low priority, so the basic operation as the image forming apparatus is Maintained.
JP-A-9-168243

  However, since the above-mentioned invention sets the priority in a fixed manner in advance, when viewed from the user, for example, if the power supply of the main control unit fails while the facsimile unit having a low priority is transmitting a facsimile, Power is supplied to the main control unit having a high priority and the basic operation as the image forming apparatus is maintained. However, the power supply unit of the facsimile unit is stopped, and there is an inconvenience that the facsimile transmission cannot be performed temporarily.

  The present invention has been made in view of such circumstances, and a first object of the present invention is to execute a multi-function image forming apparatus even if a failure occurs in a power supply apparatus while a predetermined function is being performed. The function is to be maintained until the function ends. The second object is to realize the maintenance function by simple circuit means. The third purpose is to ensure that a failure can be recovered after the function being executed is completed.

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a plurality of job execution units that execute different types of jobs; and a plurality of power supply units connected in parallel to supply power to the job execution units. Means for detecting an abnormality of the means;
Means for determining whether or not the job execution means is executing a job based on the detection result; means for suppressing power supply to the job execution means based on the determination result;
An image forming apparatus comprising:
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, means for determining whether or not the job execution means is executing a job based on the detection result is provided in each job execution means. An image forming apparatus characterized by the above.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the means for suppressing the power supply to the job execution means based on the determination result is a means for cutting off a power supply line of the job execution means or An image forming apparatus comprising: means for reducing the operation clock of the job execution means; means for stopping the operation clock of the job execution means; or means for resetting the operation of the job execution means.
According to a fourth aspect of the invention, there is provided the image forming apparatus according to the third aspect, further comprising means for notifying abnormality of the power supply means.

  According to the present invention, in an image forming apparatus having multiple functions, even if a failure occurs in the power supply apparatus while a predetermined function is being executed, the function being executed is maintained until the function is completed. Therefore, there is no inconvenience for the user that the job being executed is interrupted. Further, the maintenance function can be realized by simple circuit means, and furthermore, the failure can be reliably recovered after the function being executed is completed.

  First, the overall configuration of an image forming apparatus in which the present invention is implemented will be described with reference to FIGS. The image forming apparatus is a composite image forming apparatus having a copy function, a scanner function, a printer function, and a facsimile function. The copy function, the printer function, the scan function, and the facsimile function are sequentially performed by an application switching key of the operation unit. It is possible to switch to and select. The copy mode is selected when the copy function is selected, the print mode is selected when the printer function is selected, the scan mode is selected when the scan function is selected, and the facsimile mode is selected when the facsimile mode is selected.

FIG. 1 is a schematic configuration diagram of an image forming apparatus in which the present invention is implemented, and FIG. 2 is a block configuration diagram of a control unit of the image forming apparatus.
In FIG. 1 and FIG. 2, when the copy mode is selected, a document stack placed on the document table 102 of the automatic document feeder (hereinafter referred to as ADF) 101 has a start key on the operation unit. When pressed, the lowermost document is fed to a predetermined position on the contact glass 105 by the feeding roller 103 and the feeding belt 104. The ADF 101 has a count function that counts up the number of documents every time a document is fed. The document on the contact glass 105 is discharged onto a sheet discharge table 108 by a feeding belt 104 and a discharge roller 107 after image information is read by an image reading device 106 as an image input unit.

  When the document set detector 109 detects that the next document is present on the document table 102, the lowermost document on the document table 102 is similarly contacted by the feed roller 103 and the feed belt 104. It is fed to a predetermined position on the glass 105. After the image information is read by the image reading device 106, the original on the contact glass 105 is discharged onto the paper discharge tray 108 by the feeding belt 104 and the discharge roller 107. The feed roller 103, the feed belt 104, and the discharge roller 107 are driven by a carry motor.

  The first paper feeding device 110, the second paper feeding device 111, and the third paper feeding device 112 as paper feeding means were loaded on the first tray 113, the second tray 114, and the third tray 115, respectively, when selected. The transfer paper is fed, and the transfer paper is transported by the vertical transport unit 116 to a position where it contacts the photoconductor 117 as an image carrier. The photoreceptor 117 is driven to rotate by a main motor using, for example, a photoreceptor drum.

  Image data read from the document by the image reading device 106 is converted into optical information by a writing unit 118 as writing means via an image processing means (not shown), and the photosensitive drum 117 is uniformly charged by a charger (not shown). After that, it is exposed with light information from the writing unit 118 to form an electrostatic latent image. The electrostatic latent image on the photosensitive drum 117 is developed by the developing device 119 to become a toner image.

  The conveyance belt 120 serves as a sheet conveyance unit and a transfer unit, and a transfer bias is applied from a power source. The conveyance belt 120 conveys transfer paper from the vertical conveyance unit 116 to the photosensitive drum 117 at a constant speed, and the toner on the photosensitive drum 117. Transfer the image to transfer paper. The transfer paper is fixed with a toner image by a fixing device 121 and is discharged to a paper discharge tray 123 by a paper discharge unit 122. The photosensitive drum 117 is cleaned by a cleaning device (not shown) after the toner image is transferred. The photosensitive drum 117, the charger, the writing unit 118, the developing device 119, and the fixing device 121 constitute an image forming unit that forms an image on transfer paper based on image data.

  The above operation is for single-sided copying in the normal copy mode. However, when copying an image on both sides of transfer paper in the double-sided mode, the front side is fed from one of the paper feed trays 113 to 115. On the other hand, the transfer paper on which the image is formed as described above is switched by the paper discharge unit 122 to the double-sided paper feed path 124 side instead of the paper discharge tray 123 side, is switched back by the reversing unit 125, and the front and back are reversed It is conveyed to the duplex conveying unit 126.

  The transfer paper transported to the double-sided transport unit 126 is transported to the vertical transport unit 116 by the double-sided transport unit 126, transported to the position where it abuts on the photoconductive drum 117 by the vertical transport unit 116, and is transferred onto the photoconductive drum 117. The toner image formed in the same manner as described above is transferred to the back surface, and the toner image is fixed by the fixing device 121 to form a duplex copy. This double-sided copy is discharged to the paper discharge tray 123 by the paper discharge unit 122.

  Further, when the transfer paper is reversed and discharged, the transfer paper that is switched back by the reversing unit 125 and turned upside down is not conveyed to the duplex conveying unit 126 but is discharged via the reverse discharge conveyance path 127. The paper is discharged to the paper discharge tray 123 by the unit 122.

Here, each module of the scanner engine 2, the plotter engine 1, the FAX unit 4, the controller 3, and the HDD 5 in FIG.
a) When the copy mode is selected, the plotter engine 1 and the scanner engine 2
b) When the print mode is selected, the plotter engine 1, the controller 3 or the HDD 5
c) When the scan mode is selected, the scanner engine 2 and the HDD 5
d) When the facsimile transmission mode is selected, the FAX unit 4, the plotter engine 1 or the HDD 5 are operated.

  That is, when the copy mode is selected, the image data read by the scanner engine 2 is transferred to the plotter engine 1 by the operation from the operation unit, and is output to the transfer paper. When the productivity of the scanner engine 2 is higher than the productivity of the plotter engine 1, the productivity difference can be absorbed by interposing the HDD 5 between the scanner engine 2 and the plotter engine 1.

  When the print mode is selected, the image data obtained by converting the format of the data transferred from the PC by the controller 3 is input to the writing unit 118 of the plotter engine 1 and is output to the transfer paper by the image forming means described above.

  In the scan mode, the image data read by the scanner engine 2 is stored in the HDD 5. The operation in the scan mode can be performed on the PC via the controller 3 or can be performed via the operation unit.

  In the facsimile transmission mode, the image data read by the scanner engine 2 is output to the public line via the FAX unit 4 by an operation from the operation unit. The image data in the HDD 5 can be output to the public line via the FAX unit 4.

  In the facsimile reception mode, image data transferred from the public line is transferred to the plotter engine 1 via the FAX unit 4 and output to the transfer paper. Also, image data from the FAX unit 4 can be stored in the HDD 5.

  As described above, the unit that operates in each mode is different, and the unit that further operates in the same mode depends on whether or not the memory module is used. That is, the operation unit is appropriately switched depending on the operation mode (job).

Next, an image forming apparatus according to an embodiment of the present invention will be described.
FIG. 3 is a block diagram of the image forming apparatus according to the embodiment of the present invention. In the figure, components 1 to 5 are the same as those described in FIG. The same applies to the following description of the embodiment.

  In FIG. 3, the power supply device 10 includes control power supply modules 11 to 14, a monitoring power supply module 15, a drive power supply module 16, and a control output abnormality detection module 20 connected in parallel. When the FAX unit 4 has an optional configuration, the total power supply capability of the control power supply modules 11 to 13 covers the maximum power of the control power supply in each operation mode of the plotter engine 1, the scanner engine 2, and the controller 3. If the FAX unit 4 is expanded, a control power supply module 14 may be further attached to the power supply device 10.

  The drive power supply of the control output abnormality detection module 20 uses the output of the monitoring power supply module 15.

  The drive power supply module 16 is mainly used for a drive unit such as a motor, a clutch, and a solenoid of the plotter engine 1. Further, the drive power supply module 16 can be stepped down by a voltage regulator or the like and used as a drive power supply for the control output abnormality detection module 20 without providing the dedicated monitoring power supply module 15.

  The control output abnormality detection module 20 monitors the output state of the control power supply modules 11 to 14 and outputs a control power supply abnormality detection signal when an abnormality of at least one control power supply module is detected. The control power supply abnormality detection signal is connected in parallel to the I / O port of each CPU mounted on the plotter engine 1, the scanner engine 2, the controller 3, and the FAX unit 4.

  Subsequently, the control output abnormality detection module 20 will be specifically described.

  FIG. 4 is a diagram showing an internal circuit configuration of the control output abnormality detection module 20. In the figure, a control output abnormality detection circuit 21 that constitutes the control power supply module 11 is composed of a comparator 31 and a voltage dividing circuit 32, and outputs the output voltage of the control power supply module 11 and the specified voltage of the voltage dividing circuit 32. Comparison is made by the comparator 31.

  When the output voltage of the control power supply module 11 is a normal value, that is, higher than the specified voltage of the voltage dividing circuit 32, an H level is output. When it is lower than the voltage, L level is output. For example, when the guaranteed output voltage value of the control power supply module 11 is 5V ± 3%, the specified voltage of the voltage dividing circuit 32 may be set to 4.8V. In a normal state, the output voltage of the control power supply module 11 must show a normal value (5 V ± 3% in the above example). The control output abnormality detection circuits 22 to 24 have the same configuration requirements as the control output abnormality detection circuit 21 except that the control power supply modules to be detected are different. The outputs of the control output abnormality detection circuits 21 to 24 are combined by the NAND circuit 35 and output as a control power supply abnormality detection signal. That is, if all the outputs of the control power supply modules 11 to 14 are normal, the control power supply abnormality detection signal is H level, and the output of at least one of the control power supply modules 11 to 14 is abnormal. In some cases, the control power supply abnormality detection signal becomes L level.

  Each CPU mounted in the plotter engine 1, the scanner engine 2, the controller 3, and the FAX unit 4 polls the control power supply abnormality detection signal input to the I / O port, and when the L level is detected, the power supply device It is recognized that 10 abnormalities have occurred.

  As a modification of the control output abnormality detection module, there are an example using two sets of voltage comparison circuits and an example using a temperature comparison circuit.

  FIG. 5 is a diagram showing a configuration of an internal circuit of a control output abnormality detection module using two sets of voltage comparison circuits. In the figure, the control output abnormality detection circuit 21 constituting the control power supply module 11 is further constituted by a comparator 33 and a voltage dividing circuit 34 in addition to the comparator 31 and the voltage dividing circuit 32, and the control power supply module is constituted by one comparator. When the output voltage of the control power supply module is high (5.2 V or more) is detected by the other comparator. Then, the outputs of the two sets of comparators are synthesized by the AND circuit 36 and output. The control output abnormality detection circuits 22 to 24 have the same circuit configuration except that the control power module to be detected is different. The outputs of the control output abnormality detection circuits 21 to 24 are further combined by the NAND circuit 35 and output as a control power supply abnormality detection signal.

  FIG. 6 is a diagram illustrating an internal circuit configuration of a control output abnormality detection module that uses a temperature comparison circuit. In this case, the temperature of the control power supply module is detected by a thermistor installed in the power supply unit. In the figure, the thermistor 37 detects the temperature of the control power supply, and the detected value is converted into a voltage by the control output abnormality detection circuit 21, and this voltage is compared with a specified voltage set by the voltage dividing circuit 32. As a result, when the temperature of the control power supply is higher than the specified temperature, the control power supply module 11 determines that there is an abnormality. The configuration of the control output abnormality detection circuits 22 to 24 is the same. The outputs of the control output abnormality detection circuits 21 to 24 are further combined by the NAND circuit 35 and output as a control power supply abnormality detection signal.

  Here, it is assumed that, for example, the module 11 is out of the control power supply modules 11 to 14 described above. The loads of the control power supply modules 11 to 14 are the plotter engine 1, the scanner engine 2, the controller 3, the FAX unit 4, and the HHD 5, and these loads are in the normal state with the total power supply capability of the four power supply modules 21 to 24. In contrast, the power supply module 11 must be covered by three power supply modules 22 to 24 due to a failure of the power supply module 11. Therefore, since the control power supply modules 22 to 24 have an output current exceeding a specified value, an overcurrent detection function (not shown) works to cut off the output. As a result, the image forming apparatus is brought into an operation stop state, and if this stop is being executed, the job may be lost. Such a situation occurs in the same manner even when a control power module other than the control power module 11 fails.

Hereinafter, an image forming apparatus according to an embodiment of the present invention that avoids such a situation will be described in detail.
(Embodiment 1) In the image forming apparatus according to this embodiment, the control output abnormality detection module 20 detects a power supply abnormality of any one of the control power supply modules 11 to 14, and the abnormal output is detected by the scanner engine 2 and the controller 3. When transferred to the FAX unit 4 and the plotter engine 1, the CPUs of the scanner engine 2, the controller 3, the FAX unit 4 and the plotter engine 1 determine whether the control power supply module is abnormal, Whether or not the job is being executed. When it is determined that the job is being executed, the execution is continued, and when it is determined that the job is not being executed, the power supply to its own unit is cut off by itself.

  That is, during execution of a copy job, for example, when a failure occurs in the power supply module 11 and the output voltage decreases and becomes lower than the specified voltage of the voltage dividing circuit 32 of the control output abnormality detection circuit 21, the output of the comparator 31 becomes H It changes from level to L level. As a result, the control power supply abnormality detection signal output from the control output abnormality detection module 20 changes from the H level to the L level. Then, each CPU mounted on the plotter engine 1, the scanner engine 2, the controller 3, and the FAX unit 4 recognizes the occurrence of an abnormality in the power supply device 10.

  At this time, the CPUs of the plotter engine 1 and the scanner engine 2 determine that their units are operating units in the copy mode and are executing a copy job, and continue executing the job. Further, the CPU of the controller 3 and the FAX unit 4 determines that its own unit is a non-operating unit in the copy mode, and shuts off the power supply line supplied to its own unit.

  Even in the case of a mode in which image data is temporarily stored in the HDD 5 from the scanner engine 2 via the controller 3 even if it is a copy job, the image data is transferred from the HDD 5 to the plotter engine 1 and the job is executed. The controller 3 that controls the plotter engine 1 and the HDD 5 may continue the job being executed, and the scanner engine 2 and the FAX unit 4 may stop their operations.

  When the occurrence of an abnormality in the power supply apparatus 10 is recognized during execution of the print job, the plotter engine 1 and the controller 3 which are operation units in the print mode continue the job being executed. On the other hand, the scanner engine 2 and the FAX unit 4 which are non-operating units in the print mode themselves shut down the power and stop the operation.

  When the occurrence of an abnormality in the power supply apparatus 10 is recognized during the execution of the scan job, the controller 3 that controls the scanner engine 2 and the HDD 5 that are operation units in the scan mode continues the job being executed. On the other hand, the plotter engine 1 and the FAX unit 4, which are non-operating units in the scan mode, shut down the power by themselves and stop the operation.

  Further, when the occurrence of an abnormality in the power supply apparatus 10 is recognized during execution of the facsimile transmission job, the scanner engine 2 and the FAX unit 4 which are operation units in the facsimile transmission mode continue the job being executed. On the other hand, the plotter engine 1 and the controller 3, which are non-operating units in the facsimile transmission mode, shut down the power by themselves.

  Even in the case of a facsimile transmission job, in a mode in which image data is stored in the HDD 5 in advance and the image data is transferred to the FAX unit 4 to execute the job, the controller 3 that controls the HDD 5 The job that is being executed by the FAX unit 4 may be continued, and the plotter engine 1 and the scanner engine 2 may stop their operations.

  Furthermore, when the occurrence of an abnormality in the power supply device 10 is recognized during execution of the facsimile reception job, the plotter engine 1 and the FAX unit 4 which are operation units in the facsimile reception mode continue the job being executed. On the other hand, the scanner engine 2 and the controller 3, which are non-operating units in the facsimile reception mode, shut down the power supply themselves and stop the operation.

  Even in the case of a facsimile reception job, if the image data from the FAX unit 4 is stored in the HDD 5 and the job is executed, the controller 3 that controls the HDD 5 and the FAX unit 4 continue the job being executed. The plotter engine 1 and the scanner engine 2 may stop their operations.

  FIG. 7 is a diagram showing the configuration of the power cutoff circuit of each unit. In the figure, the drive power supply Vcc of the CPU 52 of the unit is connected to the power supply bus via a relay 51. The relay 51 is turned on when either a power ON signal 54 (described later) or an I / O port 53 of the CPU 52 is at an H level, and supplies power to the CPU 52 from the power bus. The reset IC 56 detects the drive power supply voltage of the CPU 52, and resets the CPU 52 to stop the processing operation of the CPU 52 when it is below a predetermined value.

  The initial value of the I / O port 53 of the CPU 52 is an input port (HZ state when viewed from the outside), and operates as an output port by setting an internal register of the CPU 52. The I / O port 53 of the CPU 52 is controlled to output an H level in a normal state, and detects the control power supply abnormality detection signal from the control output abnormality detection module 20, thereby setting the I / O port 53 to L. Level output.

  The power ON signal 54 is a signal from a control unit (not shown) driven by the output of the monitoring power supply module 15 and is a three-state (H level, L level, HZ) output. The output circuit of the power ON signal 54 may be in the control output abnormality detection module 20 in the power supply device 10.

  A pull-down resistor 55 is provided to fix the operation of the relay 51 in the off state when both the I / O port 53 of the CPU 52 and the power ON signal 54 are in the HZ state.

  FIG. 8 is a diagram illustrating an operation sequence of the power supply apparatus. The ON sequence of the power supply device 10 will be described with reference to FIG. 7. When the power supply device 10 is on, the power supply ON signal 54 outputs an H level. As a result, the relay 51 is turned on, and a drive voltage is applied to the power supply terminal (Vcc) of the CPU 52. After a predetermined reset period after the drive voltage of the reset IC 56 reaches a predetermined voltage, the CPU 52 starts an initialization process. The CPU 52 sets the internal register to set the I / O port 53 as an output port and outputs an H level. Thereafter, the output of the power ON signal 54 is set to the HZ state. That is, the power ON signal 54 needs to output H level during the operation time of the relay 51, the reset period of the reset IC 56, and the period longer than the accumulated time of processing time until the CPU 52 sets the I / O port 53 to H level. is there.

  Next, the operation stop of the unit when a part of the control power supply modules 11 to 14 fails will be described. The operation or stop of the unit is performed by releasing or not releasing the mask of the I / O port.

  That is, the CPU 52 detects the logic of the control power supply abnormality detection signal from the control output abnormality detection module 20 at the I / O port 57. When executing the operation job, the I / O port 57 is masked by the internal register setting of the CPU 52, and when the operation job is completed, the masking of the I / O port 57 is cancelled.

  When it is detected that the I / O port 57 has changed from the H level to the L level when the I / O port 57 is unmasked (there is no operation job), the CPU 52 outputs the L level to the I / O port 53. . At this time, since the power ON signal 54 is in the HZ state, the relay 51 is turned off. As a result, the power terminal (Vcc) of the CPU 52 is disconnected from the power bus, and the voltage decreases. Then, the reset IC 56 outputs a reset signal, and the CPU 52 stops the processing operation. The I / O port 53 of the CPU 52 is an input port which is an initial value (HZ state when viewed from the outside), but the relay 51 is kept off by the pull-down resistor 55. As a result, the operation of the unit is completely stopped.

  FIG. 9 is an operation flowchart of the unit including the operation stop of the unit due to the failure of the control power supply module. In the figure, when the image forming apparatus is powered on, this operation starts and the unit is initialized (S1). Accordingly, the I / O port 53 becomes H level (S2), and the CPU determines whether there is an operation job (S3). If there is no operation job, the masking of the I / O port 57 is canceled (S4), and it is determined whether or not the I / O port 57 is at the H level (S5). When the I / O port 57 is not at the H level, the I / O port 53 becomes the L level, the relay is turned off (S6), and the operation of the unit is stopped.

  If there is an operation job in the operation step S3, the CPU masks the I / O port 57 (S7) and executes the job (S8). Then, the process returns to step S3 for determining whether or not there is a job.

  Subsequently, the operation stop due to the failure of the power supply module of the plotter engine 1 to which both the control power supply modules 11 to 14 and the drive power supply module 15 are input will be described. The operation or stop of the unit (plotter engine) is also performed by releasing or not releasing the mask of the I / O port.

FIG. 10 is a diagram illustrating a configuration of a power cutoff circuit of the plotter unit.
In the figure, the driving power source of the CPU 52 is connected via the relay 51 from the power source bus of the control power source module. The relay 51 is turned on when either the power ON signal 54 or the I / O port 53 of the CPU 52 is at the H level, and supplies power to the CPU 52 from the power bus.

  A load 72 such as a motor, a clutch, or a solenoid is connected via a relay 71 from a power supply bus of the drive power supply module. The relay 71 is turned on when either the power ON signal 54 or the I / O port 73 of the CPU 52 is at the H level, and supplies power to the load 72 from the power bus.

  The reset IC 56 detects the drive power supply voltage of the CPU 52, and resets the CPU 52 to stop the processing operation of the CPU 52 when it is below a predetermined value.

  The initial value of the I / O ports 53 and 73 of the CPU 52 is an input port (HZ state when viewed from the outside), and operates as an output port by setting an internal register of the CPU 52. The I / O port 53 of the CPU 52 is controlled to output an H level in a normal state, and detects the control power supply abnormality detection signal from the control output abnormality detection module 20, thereby setting the I / O port 53 to L. Level output.

  The power ON signal 54 is a signal from a control unit (not shown) driven by the output of the monitoring power supply module 15 and is a three-state (H level, L level, HZ) output. The output circuit of the power ON signal 54 may be in the control output abnormality detection module 20 in the power supply device 10.

  When both the I / O port 53 of the CPU 52 and the power ON signal 54 are in the HZ state, the operation of the relay 51 is fixed in the OFF state, or both the I / O port 73 of the CPU 52 and the power ON signal 54 are H. A pull-down resistor 55 is provided to fix the operation of the relay 71 in the OFF state in the −Z state.

  FIG. 11 is a diagram illustrating an operation sequence of the power supply device. The ON sequence of the power supply apparatus 10 will be described with reference to FIG. 10. In the figure, when the power supply apparatus 10 is turned on, the power ON signal 54 outputs an H level. As a result, the relay 51 and the relay 71 are turned on, and the control power supply is applied to the power supply terminal (Vcc) of the CPU 52 and the drive power supply is applied to the load 72. After a predetermined reset period after the drive voltage of the reset IC 56 reaches a predetermined voltage, the CPU 52 starts an initialization process. The CPU 52 sets the internal register to set the I / O ports 53 and 73 as output ports and outputs an H level. Thereafter, the output of the power ON signal 54 is set to the HZ state. That is, the power ON signal 54 is H during the operation time of the relay 51 and the relay 71, the reset period of the reset IC 56, and the period equal to or longer than the accumulated time of the processing time until the CPU 52 sets the I / O ports 53 and 73 to the H level. The level needs to be output.

  The operation stop of the unit when a part of the control power supply modules among the control power supply modules 11 to 14 fails will be described. The operation or stop of the unit is also performed by releasing or not releasing the mask of the I / O port.

  That is, the CPU 52 detects the logic of the control power supply abnormality detection signal from the control output abnormality detection module 20 at the I / O port 57. When executing the operation job, the I / O port 57 is masked by the internal register setting of the CPU 52, and when the operation job is completed, the masking of the I / O port 57 is cancelled.

  When the I / O port 57 detects that the I / O port 57 has changed from the H level to the L level in the mask release state (the state where there is no operation job), the CPU 52 first sets the I / O port 73 to the L level. Output. At this time, since the power ON signal 54 is in the HZ state, the relay 71 is turned off. As a result, the driving power source for the load 72 is disconnected from the power bus, and the voltage decreases. Next, the CPU 52 outputs an L level to the I / O port 53. At this time, since the power ON signal 54 is in the HZ state, the relay 51 is turned off. As a result, the power terminal (Vcc) of the CPU 52 is disconnected from the power bus, and the voltage decreases. Then, the reset IC 56 outputs a reset signal, and the CPU 52 stops the processing operation. The I / O port 53 of the CPU 52 is an input port that is an initial value (HZ state when viewed from the outside), but the relay 51 and the relay 71 continue to be in an off state by the pull-down resistor 53. As a result, the operation of the unit is completely stopped.

  (Embodiment 2) The image forming apparatus according to the present embodiment executes a job by minimizing the operation clock of the unit when some of the control power supply modules 11 to 14 fail. continue.

  FIG. 12 is a flowchart of processing for executing a job while minimizing the operation clock of the unit. In the figure, when the power of the image forming apparatus is turned on, this operation starts, the unit is initialized (S11), and the CPU determines whether there is an operation job (S12). If there is no operation job, the mask of the I / O port 57 is released (13), and it is determined whether or not the I / O port 57 is at the H level (S14). When the I / O port 57 is not at the H level, the I / O port 53 becomes the L level and the clock setting is changed to the minimum (S15).

  If there is an operation job in the operation step S12, the CPU masks the I / O port 57 (S16) and executes the job (S17). Then, the process returns to step S12 for determining whether or not there is a job.

  According to the present embodiment, when the CPU 52 has the power saving mode, the power saving mode can be set.

  (Embodiment 3) The image forming apparatus according to the present embodiment operates the crystal oscillator of a unit that is not executing a job when some of the control power supply modules 11 to 14 fail. Stop and continue the running job.

  FIG. 13 is a configuration diagram of a circuit for stopping the operation of the crystal oscillator. In the figure, the operation clock of the CPU 52 is generated by multiplying the output of the crystal oscillator 61 by the internal PLL circuit of the CPU 52. The crystal oscillator 61 includes an enable terminal, and the output is stopped when the enable terminal is at L level. A control power supply abnormality detection signal from the control output abnormality detection module 20 is connected to one input of the OR circuit 62, and an I / O port 63 of the CPU 52 is connected to the other input. That is, the OR circuit 62 outputs an L level when both the control power supply abnormality detection signal and the I / O port 63 are at an L level, and thereby the output of the crystal oscillator 61 can be stopped.

  The initial value of the I / O port 63 of the CPU 52 is an input port (HZ state when viewed from the outside). At this time, in order to fix the output of the OR circuit 62 at the H level, the I / O port 63 is pulled up with a resistor. Moreover, it operates as an output port by setting an internal register of the CPU 52. When executing the operation job, the CPU 52 sets the I / O port 63 to the H level by the internal register setting of the CPU 52, and sets the I / O port 63 to the L level when the operation job is completed. That is, when an operation job is executed, the output of the OR circuit 62 becomes H level so that the output of the crystal oscillator 61 is not stopped regardless of whether the control power supply abnormality detection signal is H level or L level. Can be. When an abnormality occurs in at least one control power supply module when the operation job is not executed and the control power supply abnormality detection signal becomes L level, the output of the OR circuit 62 becomes L level, and the crystal oscillator 61 Stop output.

FIG. 14 is a flowchart of the operation for stopping the operation of the crystal oscillator.
In the figure, when the power of the image forming apparatus is turned on and this operation starts, the unit is initialized (S21). The CPU sets the I / O port 63 to the H level (S22), and determines whether there is an operation job (S23). If there is no operation job, the I / O port 63 is set to L level (S24), and it is further determined whether or not the control abnormal power supply detection signal is normal (H level) (S25). If not normal, the output of the crystal oscillator 61 is stopped (S26). If normal, the process returns to step S22, which is an initialization state. If there is an operation job, the job is executed (S27) with the I / O port 63 set to H level (S27), and the process returns to the operation of step S22, which is in the initialized state after the job is completed.

  (Embodiment 4) An image forming apparatus according to this embodiment forcibly forces a CPU of a unit that is not executing a job when some of the control power supply modules 11 to 14 fail. Reset and continue job execution.

  FIG. 15 is a configuration diagram of a circuit for forcibly resetting the CPU of a unit that is not executing a job. In the figure, the reset IC 56 is an open drain output. A control power supply abnormality detection signal from the control output abnormality detection module 20 is connected to one input of the OR circuit 62, and the I / O port 63 of the CPU 52 is connected to the other input. The OR circuit 62 outputs the L level when both the control power supply abnormality detection signal and the I / O port 63 are at the L level. Then, the transistors 64 and 65 are turned on, and the reset terminal of the CPU 52 becomes L level. That is, the CPU 52 is forcibly reset when both the control power supply abnormality detection signal and the I / O port 63 are at the L level.

  The initial value of the I / O port 63 of the CPU 52 is an input port (HZ state when viewed from the outside). At this time, in order to fix the output of the OR circuit 62 at the H level, the I / O port 63 is pulled up with a resistor. Moreover, it operates as an output port by setting an internal register of the CPU 52.

  When executing the operation job, the CPU 52 sets the I / O port 63 to the H level by setting the internal register of the CPU 52, and sets the I / O port 63 to the L level when the operation job is completed. That is, when the operation job is executed, the output of the OR circuit 62 is at the H level regardless of whether the control power supply abnormality detection signal is at the H level or the L level, and the transistors 64 and 65 remain off. To do. If an abnormality occurs in at least one control power supply module when an operation job is not executed and the control power supply abnormality detection signal becomes L level, the output of the OR circuit 62 becomes L level, and the CPU 52 is forcibly reset. To do. The operation flow in this control can be realized by the flow described in FIG.

  As described above, according to the image forming apparatus of each embodiment, even if an abnormality occurs in the control power supply module, the job currently being executed is continuously executed as it is. For this reason, the user may not be aware of the power supply abnormality. Therefore, the image forming apparatus notifies the user of the occurrence of power supply abnormality.

  FIG. 16 is a block diagram of the image forming apparatus according to the embodiment of the present invention, which is basically the same as the block diagram of FIG. In the figure, the operation unit 7 has a key operation panel and a liquid crystal display unit, and the output of the monitoring power supply module 15 is used as the drive power source. The control power supply abnormality detection signal from the control output abnormality detection module 20 is also connected in parallel to the I / O port of the CPU mounted on the operation unit 7. The CPU detects the logic of the control power supply abnormality detection signal from the control output abnormality detection module 20 with the I / O port. Accordingly, when detecting that the I / O port has changed from the H level to the L level, the CPU notifies the liquid crystal display unit provided in the operation unit of the failure of the power supply device 10.

  According to the present embodiment, the user may not be aware of the power failure as long as the job is executed, but since the failure is notified, the repair work for the power failure can be reliably performed after the job is completed. .

  As described above, the present invention is suitable for use in a multifunctional image forming apparatus in which power is supplied from a plurality of power supply sources, and particularly for large color copiers, etc. It is suitable for use in an image forming apparatus for processing.

1 is a schematic configuration diagram of an image forming apparatus in which the present invention is implemented. 2 is a block configuration diagram of a control unit of the image forming apparatus. FIG. 1 is a block configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the internal circuit structure of the output abnormality detection module for control. It is a figure which shows the internal circuit structure of the output abnormality detection module for control which uses 2 sets of voltage comparison circuits. It is a figure which shows the internal circuit structure of the output abnormality detection module for control which uses a temperature comparison circuit. It is a figure which shows the structure of the power cutoff circuit of each unit. It is a figure which shows the operation | movement sequence of a power supply device. It is an operation | movement flowchart of the said unit including the operation | movement stop of the said unit by failure of the power supply module for control. It is a figure which shows the structure of the power cutoff circuit of a plotter unit. It is a figure which shows the operation | movement sequence of a power supply device. FIG. 10 is a flowchart of processing for executing a job while minimizing the operation clock of the unit. It is a block diagram of the circuit which stops operation | movement of a crystal oscillator. It is a flowchart of the operation | movement which stops operation | movement of a crystal oscillator. It is a block diagram of a circuit for forcibly resetting the CPU of a unit that is not executing a job. 1 is a block configuration diagram of an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

  101 .. Automatic document feeder, 102 .. Document base, 103 .. Feed roller, 104 .. Feed belt, 105 .. Contact glass, 106 .. Image reading device, 107 .. Discharge roller, 108.・ Discharge stand, 109 ..Document set detector, 110 ..First paper feeder, 113 ..First tray, 116 ..Vertical transport unit, 117 ..Photoconductor, 118 ..Write unit, 119・ Developing device 120... Conveying belt 121.. Fixing device 122.

Claims (4)

In an image forming apparatus including a plurality of job execution units that execute different types of jobs and a plurality of power supply units connected in parallel to supply power to the job execution units,
Means for detecting an abnormality in the power supply means;
Means for determining whether the job execution means is executing a job based on the detection result;
Means for suppressing power supply to the job execution means based on the determination result;
An image forming apparatus comprising: The image forming apparatus according to claim 1.
An image forming apparatus, wherein each job execution unit includes means for determining whether or not the job execution unit is executing a job based on the detection result. The image forming apparatus according to claim 1 or 2,
The means for suppressing power supply to the job execution means based on the determination result is a means for cutting off the power supply line of the job execution means, a means for reducing the operation clock of the job execution means, or an operation clock of the job execution means An image forming apparatus characterized in that the image forming apparatus is means for stopping the operation or means for resetting the operation of the job execution means.   4. The image forming apparatus according to claim 3, further comprising means for notifying abnormality of the power supply means.

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