JP2007206666A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To normally provide an image, even if abnormality occurs, when switching a main power source and an auxiliary power source. <P>SOLUTION: The image forming apparatus is equipped with a main power source device 42; an auxiliary power source device constituted of a capacitor 44; a switching circuit 46 for switching the two power source devices; and a control part 60 controlling the switching of the switching circuit 46, and is actuated by power from the auxiliary power source device in a predetermined period. When detecting the abnormality, when switching from the auxiliary power source device to the main power source device, the control part 60 makes the printing data which are being formed reprinted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an image forming apparatus that is used by switching a load between a main power source and an auxiliary power source.

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. Also, regarding the fixing device, fixing is performed in order to reduce factors such as the waiting time until the fixing device rises and the factors of the image forming apparatus itself such as a temporary interruption of the operation due to a decrease in the fixing temperature during the printing or copying operation and the waiting time of the operator. There is a tendency to increase the power supplied to the heater. 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.

Therefore, for example, in Patent Document 1, the power consumption is predicted, and when the predicted power consumption exceeds the suppliable power of the main power supply, power is supplied to a part of the load by the auxiliary power supply, and the maximum supply of the power supply line is provided. A power leveling technique that does not exceed the possible power is disclosed.
JP 2004-236492 A

However, the technique disclosed in Patent Document 1 does not include a detailed description regarding the power source switching operation between the auxiliary power source and the main power source, and discloses an abnormality detection process at the time of power source switching and a failure detection process of the auxiliary power source device. It has not been.

The present invention has been made in view of such a state of the prior art, and an object thereof is to be able to normally provide an image even when an abnormality occurs when switching between a main power source and an auxiliary power source.

In order to achieve the object, the first means includes a main power supply device, an auxiliary power supply device capable of storing electricity,
In an image forming apparatus that includes a switching unit that switches between the two power supply units and a control unit that controls switching of the switching unit and operates by one of the power supply units for a predetermined period, When an abnormality is detected when switching to the apparatus, the print data that was being imaged is printed again.

When the second means detects an abnormality in the one power supply device used for image formation under the same preconditions as the first means, the second means switches to the other power supply device and discharges the printing paper being imaged. It is characterized by doing.

The third means is characterized in that, in the second means, after the printing paper being imaged is discharged, the print data being imaged is printed again.

The fourth means is characterized in that in the second or third means, the printing paper being imaged is discharged to a place different from a predetermined paper discharge destination.

The fifth means is characterized in that, in the second or third means, the printing paper being imaged is discharged to a position different from a predetermined position on the same paper discharge tray.

A sixth means is characterized in that, in the first to fifth means, the one power supply device is an auxiliary power supply device, and the other power supply device is a main power supply device.

A seventh means is the first to fifth means, wherein the main power supply device outputs AC power and DC power, the auxiliary power supply device outputs DC power that can be stored, and the DC power of the main power supply device. And the DC power of the auxiliary power unit is switched.

In the embodiment described later, the main power supply device is designated by reference numeral 42, and the auxiliary power supply device is designated by the capacitor 44.
The switching means corresponds to the switching circuit 46, the paper discharge tray corresponds to the reference number 116, and various controls are executed by the control unit 60.

According to the present invention, when an abnormality is detected when switching the supply source from the power of the auxiliary power supply to the power of the main power supply, the control configuration is such that the print data that was being imaged is printed again. Even if an abnormality occurs during switching, it can be detected and a normal image can be provided to the operator.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 is a digital multifunction machine having a copying function, a printer function, a facsimile function, and the like. The application function key on the operation unit (not shown) can be used to select the copy function, printer function, and facsimile function in sequence. The copy mode is selected when the copy function is selected, and the printer function is selected. The printer mode is selected, and the facsimile mode is selected when the facsimile mode is selected.

The flow of image formation in the image forming apparatus 1 will be briefly described with reference to FIG. In the copy mode, the document bundle is sequentially fed to the image reading device 20 by the automatic document feeder (ADF) 10, and the image information is read by the image reading device 20. The read image information is sent to the writing unit 30 via image processing means (not shown).
Is converted into optical information. The photosensitive drum 111 in the printer unit 40 is a charger (
After being uniformly charged (not shown), exposure is performed based on optical information from the writing unit 30 to form an electrostatic latent image. The electrostatic latent image on the photosensitive drum 111 is developed by the developing device 112 to become a toner image. This toner image is transferred onto the transfer paper fed from the paper feed cassette 115 by the conveyor belt 113, and the toner image transferred onto the transfer paper is fixed by the fixing device 114 and discharged to the paper discharge tray 116. . Reference numeral 50 denotes a capacitor unit.

FIG. 2 is a block diagram showing a power supply system of the image forming apparatus of FIG. This power supply system includes a main power supply device 42 connected to an AC line 41 via a main power switch 40, and a capacitor charger 4.
3 and a capacitor 44 as an auxiliary power source charged by the power source 3. Main power supply 42
Comprises an AC / DC converter 42a and a fixing heater driving section 42b. A + 5V system load 47a and a + 24V system first load 47b (referred to as load (1) in FIG. 2) are connected to the AC / DC converter 42a, and the fixing heater driving unit 42b is fixed by the fixing device 114 of FIG. A fixing heating device 48 for heating the roller is connected. AC / DC converter 4
A switching circuit 46 for switching to the auxiliary power source is also connected to the terminal on the + 24V system first load 47b side of 2a. The switching circuit 46 includes a first voltage detection unit 49a (referred to as voltage detection (1) in FIG. 2) for detecting the output voltage of this circuit, and a + 24V system second load 47c (FIG. 2).
Is connected to a load (2). On the auxiliary power source side, a capacitor charger 43 for charging the capacitor 44, a capacitor converter 45 that operates according to the capacity and specifications of the capacitor, and a second voltage detection that detects a voltage applied from the capacitor converter to the switching circuit 46. Part (referred to as voltage detection (2) in FIG. 2) 49b. 60
The control unit controls the entire image forming apparatus 1 and sequentially operates the loads 47a to 47c according to each operation mode described later. Although not shown, the control unit 60
A CPU that controls image formation and power, a ROM that stores a program for operating this CPU, a RAM that is used as a work memory for the CPU, adjustment values such as control and timing, and power consumption for each load A nonvolatile RAM for storing the data is provided.

That is, AC power supplied from the AC line 41 via the main power SW 40 is converted to DC power by the AC / DC converter 42a included in the main power supply device 42, and a part is directly +2
It is supplied as a power source for each of the 4V and + 5V type loads 47b and 47c. The AC power is also input to the capacitor charger 43 and used to charge the capacitor 44.

The capacitor 44 as an auxiliary power source is constituted by a large capacity capacitor such as an electric double layer capacitor. In addition to the electric double layer capacitor, various selections can be made. In the present invention, 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, the terminal voltage becomes lower as it is discharged, so that the output voltage is made constant by disposing the capacitor converter 45 after the capacitor 44. Capacitor converter 45 uses any one of a boost converter, a step-down converter, and a step-up / step-down converter according to the charging voltage of the capacitor and the lower limit voltage specification.

The switching circuit 46 is based on the AC power supplied from the AC line 41, and the AC / DC converter 4
The + 24V power source generated by 2a and the + 24V power source generated through the capacitor converter 45 from the energy stored in the capacitor 44 are switched according to control by the control unit 60 and supplied to the + 24V system second load 47c. Further, the output part of the switching circuit 46 and the output part of the capacitor converter 45 have a first voltage detection part 49a and a second voltage detection part, respectively.
A voltage detector 49b is provided to monitor the voltage of the + 24V power supply.

The control part 60 operates each load 47a-47c sequentially according to each operation mode. The controller 60 also controls charging / discharging of the capacitor 44. The capacitor converter 45 generates energy from the energy accumulated in the capacitor 44 during the start-up of the device and the period up to a predetermined time after the start-up. The switching circuit 46 is switched and operated so that + 24V power is supplied to the + 24V system second load 47c. At this time, the margin generated with respect to the power supplied from the AC line 41 controls the fixing heater driving circuit 42b to increase the amount of power supplied to the fixing heating device 48.

Next, auxiliary power supply timing will be described with reference to FIG. FIG. 3 shows the image forming apparatus 1.
Is a graph of the transition of power consumption at the time of start-up, with the horizontal axis representing time and the vertical axis representing the total power consumption of the apparatus. The dotted line is power that can be supplied from the AC line.

In the fixing reload period (1) immediately after the main power supply SW 40 is turned on, in order to satisfy the start-up time required for the apparatus, a larger amount of electric power than usual is supplied to the fixing heating apparatus 48 to fix the fixing apparatus 1.
14 is raised as soon as possible to a temperature at which printing is possible. At this time, power is supplied to the + 24V system second load 47c by the auxiliary power supply so that the power obtained by subtracting the auxiliary power supply from the power of the entire apparatus does not exceed the power that can be supplied from the AC line. This makes it possible to increase the power supplied to the fixing heating device 48, compared to a device without an auxiliary power source.
Start-up time can be shortened.

Further, in the period (2) a from the start of the printing operation to the lapse of a predetermined time after the fixing reload, power is supplied to the + 24V system second load 47c by the auxiliary power source as in the case of the startup. Once the fixing device 114 reaches a temperature at which printing is possible, in order to maintain the temperature, even in a system in which the fixing heater supply power may be smaller than that at the time of fixing reloading, the printing operation is started after the fixing reloading is completed. When the motor is started, the DC load increases, and the total power including the fixing heater supply power exceeds the power that can be supplied from the AC line. To prevent the breakdown of system power supply. Also, since the drop in fixing temperature due to paper passing is large at the start of printing, it is necessary to increase the power to the fixing heating device during normal printing until the temperature stabilizes. Period (2) a until the passage of time is set as a. As a result, it is possible to increase the power supplied to the fixing heating device at the start of printing where the fixing temperature is not stable, and it is possible to improve the paper conveyance speed as compared with an apparatus without an auxiliary power source.

On the other hand, since the power stored in the auxiliary power supply is limited and continuous supply is impossible, the power to the DC load is supplied to the main power supply after the period (2) a until the fixing temperature is stabilized. To stop the auxiliary power supply. At this time, the power supplied to the fixing heating device 48 is changed to the power supplied during normal printing. The period (2) a until the fixing temperature is stabilized, which is the power supply stop timing of the auxiliary power supply, is defined as time or the number of prints to be executed, and the value may be a fixed value. When the variable value is set to, the auxiliary power supply time can be set corresponding to the fixing temperature stabilization time that is considered to change according to the operation mode, and the auxiliary power supply can be used effectively.

Up to this point, the two periods (1) and (2) a have been individually described. However, by mounting them in the apparatus in combination, the drop in the fixing temperature at the start of the printing operation in the period (2) a is suppressed. Therefore, the fixing reload time can be set low to further shorten the fixing rise time. In addition, a fixing reload period during which a large amount of power is required for the fixing heating device 48 (
1) and the period from the fixing reload to the lapse of the predetermined time have been described. However, the period can be similarly applied to other periods as long as the power is required for the fixing device 114.

The basic control of charging / discharging of the capacitor 44 as an auxiliary power source by the control unit 60 is performed according to the flowchart shown in FIG. That is, first, it is ascertained whether or not the state of the apparatus is fixing reload (step S101). Then, immediately after the main power supply SW40 is turned on or when returning from the off mode and it is determined that it is necessary to execute the fixing reload operation, the operation of the capacitor converter 45 is started (step S102) and continued. Then, the switching circuit 46 switches the power supply to the + 24V system second load 47c from the energy stored in the capacitor 44 to the + 24V power generated through the capacitor converter 45 (step S103), and can supply the power to the fixing heating device 48. Increase power (step S104)
Then, the fixing reload operation is started (step S105). Next, the completion of the fixing reload operation is confirmed (step S106). When the completion is confirmed, it is determined whether or not there is a print instruction by the operator (step S107). 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 (step S108), and the + 24V system second load 47c by the auxiliary power supply The printing operation is started with the power supplied to the printer (step S109).

After starting the printing operation, the timer in the control unit 60 is started (step S110), and when it is confirmed that a predetermined time has passed (step S111), the fixing supply power is switched to the supply power for normal printing (step S112). Subsequently, the power supply to the + 24V system second load 47c is switched to the +24 power source generated by the AC / DC converter of the main power source (step S11).
3) The capacitor converter 45 stops (step S114). If there is no print instruction in step S107 after fixing reload, the auxiliary power supply stop operation (
Steps S112 and S113) are performed.

If an abnormality occurs when the auxiliary power supply is stopped in step S113, the processing operation shown in FIG. 5 is performed. That is, when there is an auxiliary power supply stop instruction, as described in step S112 of FIG. 4, the power supply to the + 24V system second load 47c is supplied to the main power supply AC / DC converter 42a.
Switch to the +24 power supply made in At the same time, the first voltage detector 49a detects an abnormality of the load supply voltage (step S201), switches to the +24 power source created by the AC / DC converter of the main power source (step S202), and stops the capacitor converter 45. (Step S203), and the print processing is terminated (Step S204). At the end of the printing process, it is checked whether or not an abnormality has occurred at the time of switching (step S205). If an abnormality is detected, the printing process is executed again (step S206), and then the reprinting is terminated (step S206). Step S207).

AC / D of the main power supply from the output of the capacitor converter 45 is supplied to the DC load.
When switching to the output of the C converter 42a, a voltage fluctuation may occur although it is within the input voltage range of the DC load due to the difference in both output voltages. Due to the occurrence of this voltage fluctuation, the system will not be stopped, but an operation abnormality may occur. For example, when the load at the switching destination is a high-voltage power supply unit such as charging, development, or transfer, output voltage fluctuation may occur,
In the case of a motor that drives a transfer belt or the like, rotation unevenness may occur, resulting in an abnormal image. With the processing as described above, it is not necessary for the operator to check the output image, and when there is an abnormality, it is not necessary to issue a print instruction again, thereby reducing the burden on the operator.

Further, when an abnormality is detected and the printing operation is executed again, displaying this fact on the operation panel will not cause confusion for the operator. Further, after all the printing operations are completed, if an image that is determined to be abnormal due to switching is output again only when the operator requests it, the discharge that is considered by the operator when the continuous printing operation is performed. Prevents differences from the number of sheets and the order of delivery,
The confusion of the operator can be further reduced.

The first voltage detection unit 49a is configured to determine that the output voltage value is abnormal when the output voltage value is greater than or less than the specified voltage, and the specified voltage is the upper and lower limit values of the input voltage range in which the + 24V second load 47c can operate. However, when the difference in voltage between the auxiliary power supply output and the main power supply output exceeds the specified voltage, it is determined to be abnormal, and the specified voltage is a + 24V system. If the second load 47c is set to the same value as the input voltage fluctuation specification capable of operating normally, in the case of a device whose input voltage fluctuation specification is smaller than the input voltage range, abnormal image generation due to abnormal load operation and the above-mentioned An accurate correspondence with the execution of the printing operation can be taken.

FIG. 6 is a flowchart showing processing when a failure of the capacitor converter 45 is detected during supply of auxiliary power. When there is an instruction to start auxiliary power supply, steps 102 and 10 in FIG.
As described in FIG. 3, the power supply to the + 24V system second load 47c is supplied to the capacitor converter 45.
Switch to the +24 power supply made in At the same time, the failure detection process is started. First, it is confirmed based on a status flag or the like in the control unit 60 whether the auxiliary power supply is being controlled (step S300). If supply control of auxiliary power is not being controlled, the failure detection process ends (step S301). If the supply of auxiliary power is being controlled, the second voltage detector 49b starts detecting a failure of the auxiliary power supply (step S302). Then, the presence or absence of an abnormality is checked (step S303). If no abnormality is recognized, the process returns to step S300, and the fault detection is continued while the auxiliary power is being supplied even when the printing operation is started.

On the other hand, if a failure of the auxiliary power supply is detected in step S303, it is checked whether or not the failure is during the printing operation (step S304). If a failure of the auxiliary power supply is detected during the printing operation, + 24V is detected. All the operations of the system second load 47c are stopped, and the printing operation is interrupted (step S305). Next, switch the fixing power supply to that for normal printing (
In step S306, the power supply to the + 24V system second load 47c is switched to the +24 power source generated by the AC / DC converter 42a of the main power source (step S307). Further, at this time, the capacitor converter 45 has failed and is considered to be in a stopped state, but the capacitor converter 45 is protectively stopped (step S308). Then +2
Check whether the supply voltage to the 4V system second load 47c is normal (step S309),
If it is normal, it is confirmed whether or not there is a failure during the printing operation (step S310). If the printing operation is in progress, the paper that was being printed on the paper conveyance path of the apparatus is discharged out of the apparatus (step S311). The subsequent operations are performed under control of a standard system that does not use an auxiliary power source. At this time, it is not a fatal abnormality that cannot be used by the system, but a failure of the auxiliary power supply device is displayed, and a display indicating that the normal printing operation can be used is displayed on the operation panel (step S312). When the + 24V power supply voltage is confirmed after switching to the main power supply, if a normal voltage cannot be confirmed, the system is abnormal and the operator is notified that the system is in an unusable state (step S313).

Further, when discharging the paper that was being printed out of the apparatus, if the discharge destination is the location specified at the time of printing, in this case the discharge tray in a location different from the discharge tray 116 shown in the figure, the operator It is possible to prevent a paper containing an abnormal image from being mistaken for a normal output paper. At this time, if the paper discharge tray device includes a shift function that can shift the paper discharge position horizontally for each print request or each number of copies, the abnormal paper is discharged from the normal output paper. However, the same effect can be obtained.

Furthermore, after the paper that was being printed is ejected, if the data that was in the middle of printing is printed again and output from the beginning, there is no need for an operation for reprinting, which can reduce the burden on the operator. it can. The re-output timing may be after the completion of all printing operations, as in the case of the abnormal processing at the time of switching, but is different from the designated location as the paper discharge destination that was being printed as described above. In the case of the location, even immediately after the paper that was being printed is discharged, the discharge order and the number of discharged sheets can be set according to the operator's instructions. Even if a failure occurs, the operation can be completed as instructed by the print request.

As an abnormality determination method in the second voltage detector 49b, the output voltage value is equal to or higher than a specified voltage /
If the following is detected, it is determined as abnormal, and if the specified voltage is the upper and lower limit values of the input voltage specification of the + 24V system second load 47c, the above function can be satisfied. The second voltage detector 4
9b can also be used as the first voltage detection unit 49a if the detection position is used as the output unit of the switching circuit 46 and the detection operation is executed only when auxiliary power is supplied.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a power supply system of the image forming apparatus in FIG. 1. 3 is a graph showing a transition of power consumption when the image forming apparatus of FIG. 1 is started up. It is a flowchart which shows the basic control operation | movement of charging / discharging of the auxiliary power supply by the control part of FIG. It is a flowchart which shows the processing operation | movement when abnormality generate | occur | produces at the time of an auxiliary power supply stop. It is a flowchart which shows the processing operation at the time of detecting failure of a capacitor converter during auxiliary power supply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Image reading apparatus 30 Writing unit 40 Printer unit 42 Main power supply apparatus 42a AC / DC converter 42b Fixing heater drive part 44 Capacitor 45 Capacitor converter 46 Switching circuit 47a + 5V system load 47b + 24V system 1st load 47c + 24V system 1st 2 loads 48 fixing heating device 49a first voltage detection unit 49b second voltage detection unit 60 control unit 111 photosensitive drum 112 developing device 114 fixing device

Claims (7)

An image comprising a main power supply device, an auxiliary power supply device capable of storing electricity, a switching means for switching between the two power supply devices, and a control means for controlling switching of the switching means, and operated by one of the power supply devices for a predetermined period. In the forming device,
An image forming apparatus, wherein when an abnormality is detected when switching from one power supply device to another power supply device, the print data that was being imaged is printed again. An image comprising a main power supply device, an auxiliary power supply device capable of storing electricity, a switching means for switching between the two power supply devices, and a control means for controlling switching of the switching means, and operated by one of the power supply devices for a predetermined period. In the forming device,
An image forming apparatus, wherein when an abnormality is detected in one of the power supply devices used for image formation, the other power supply device is switched to discharge printing paper being imaged. 3. The image forming apparatus according to claim 2, wherein after the printing paper being imaged is discharged, the print data that was being imaged is printed again. 4. The image forming apparatus according to claim 2, wherein the printing paper being imaged is discharged to a place different from a predetermined discharge destination. 4. The image forming apparatus according to claim 2, wherein the printing paper being imaged is discharged to a position different from a predetermined position on the same discharge tray. 6. The image forming apparatus according to claim 1, wherein the one power supply device is an auxiliary power supply device, and the other power supply device is a main power supply device. The main power supply device outputs AC power and DC power, the auxiliary power supply device outputs DC power that can be stored, and the DC power of the main power supply device and the DC power of the auxiliary power supply device are switched. The image forming apparatus according to any one of claims 1 to 6.

Images