JP2003054097A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the operation time of a control means by holding the power supply voltage to the control means over a certain period even if input voltage lowers in an image forming apparatus to be operated by using AC voltage as a power supply. SOLUTION: When AC power supply voltage lowers, the operation of an engine part EG and the operation of a drive DC-DC converter 103 being the power supply thereof are stopped to suppress current consumption. A control DC-DC converter 106 uses the charge stored in a smoothing condenser 102 and the condenser 105 connected through a reverse-current preventing diode 10 to continue the feed to an engine controller 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine and a facsimile machine.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus such as a printer, a copying machine or a facsimile apparatus, it is general to use two or more kinds of power source voltages as a power source for driving an internal circuit. Because the control unit including the microprocessor that controls the operation of the device,
Most of the logic circuits that realize image signal processing and other functions operate at a low voltage (for example, 5 V), while high power such as a motor for driving the paper feeding mechanism and the photosensitive drum and a laser unit that serves as an exposure light source. This is because it is efficient to drive a mechanism that requires a higher voltage (for example, 24V).

[0003]

However, in the conventional image forming apparatus, when the power supply voltage suddenly drops during the operation of the apparatus due to the power failure of the AC power supply system, the power off operation by the user's operation error, or the like, A decrease in the power supply voltage of the operating control unit may cause a malfunction in the operation of the device. For example, if the supply voltage to the control unit drops while data is being written to the memory that records information that indicates the usage status of the device, such as the number of prints and the toner consumption status, correct data cannot be written to the memory, and It becomes impossible to correctly grasp the usage history of the device at startup. Further, for example, when the power supply voltage drops during the rotation of the motor, it is desirable to stop at least the rotation of the motor as a termination process before the function of the device stops.
If the supply voltage to the control unit drops before the power supply to the motor is stopped, the electric power is continuously supplied to the motor without being able to properly control the motor, and the motor continues to rotate during that time.

In order to solve these problems, when the power supply voltage drops, the power supply to the control unit is continued at least until the termination processing of each unit of the apparatus is completed,
It is desired that the control unit maintain its function.

The present invention has been made in view of the above problems, and in an image forming apparatus having a control means for controlling each part of the apparatus by receiving a power supply voltage converted from an AC input voltage, a power failure, an operation error, etc. It is an object of the present invention to extend the operating time of the control means by holding the power supply voltage to the control means for a certain period even when the AC input voltage is reduced by.

[0006]

An image forming apparatus according to the present invention comprises a drive means for driving each part of the apparatus, a control means for controlling the operation of the drive means and each part of the apparatus, the drive means and the control means. In order to achieve the above object, the power supply unit rectifies an AC voltage and smoothes it with a capacitance component to convert it into a DC voltage. ,
Connected to the output side of the rectification unit, connected to the output side of the rectification unit and a control voltage conversion unit for converting the DC voltage into a voltage to output a first power supply voltage, and supplying the first power supply voltage to the control means. The DC voltage is converted into a second power supply voltage, which is output to the drive means, and the drive voltage converter is supplied to the drive means, while the control means controls the AC voltage, the output voltage of the rectifier and the drive voltage converter. A voltage monitoring unit that outputs a voltage drop detection signal when at least one of the output voltages of the driving voltage conversion unit drops below a predetermined voltage value, and the voltage drop detection signal is given from the voltage monitoring unit. sometimes,
And a power supply control unit for stopping the operation of the drive voltage conversion unit (claim 1).

In the invention thus constructed, the rectifying section has a relatively large capacity capacitive component as a filter for removing pulsation of the rectified voltage, and electric energy is accumulated in this capacity. There is. Then, using the electric energy accumulated in this capacity and the electric energy supplied from the AC power source, the control voltage conversion section and the drive voltage conversion section generate respective output voltages.

Here, when the power supply voltage drops due to a power failure of the AC power supply or a power-off operation by the user, the supply of electric energy from the AC power supply is stopped. Then, the voltage monitoring unit detects this voltage drop and outputs a voltage drop detection signal, while the power supply control unit receiving this signal outputs a control command to stop the driving voltage conversion unit,
After that, the driving voltage converter does not consume the electric energy stored in this capacitor. Therefore, by allocating all the electrical energy stored in the capacitor to the first power supply voltage output by the control voltage conversion unit, the first power supply voltage is maintained for a relatively long time even after the AC power supply voltage is reduced. It is possible to maintain the function of the control means in the meantime.

Further, a backflow prevention which allows a current to flow from the rectification unit to the control voltage conversion unit between the rectification unit and the control voltage conversion unit while blocking a reverse current. And a power storage unit that is provided between the backflow prevention unit and the control voltage conversion unit and stores the electrical energy supplied from the rectification unit (claim 2).

In the invention thus configured, the electric current is accumulated in the power storage unit by the current flowing from the rectifying unit to the power storage unit, while the reverse current blocking unit blocks the current in the opposite direction. Even if the output voltage of the rectification unit rapidly decreases due to the decrease of the power supply voltage, the control voltage conversion unit generates the first power supply voltage by using the electric energy accumulated in the power storage unit, and the operation of the control unit is performed. Can be maintained.

The image forming apparatus according to the present invention is
An image forming apparatus comprising: a drive unit that drives each unit of the apparatus; a control unit that controls the operation of the drive unit and each unit of the apparatus; and a power supply unit that supplies power to the drive unit and the control unit. To achieve the above object, the power supply means includes a rectifying unit that rectifies an AC voltage and converts the AC voltage into a DC voltage, and a first power supply that is connected to an output side of the rectifying unit to convert the DC voltage into a voltage. Output voltage,
A control voltage converter for supplying to the controller, and a drive voltage converter connected to the output side of the rectifier for converting the DC voltage to output a second power supply voltage and supplying it to the driver. And a third power supply voltage having a voltage value substantially the same as the first power supply voltage using the electric energy stored in the capacitive component provided in the drive voltage conversion unit and supplied to the control means. And an auxiliary power supply unit for controlling the output voltage of the AC voltage, the output voltage of the rectification unit, and the output voltage of the drive voltage conversion unit.
Voltage monitoring unit that outputs a voltage drop detection signal when two voltages drop below a predetermined voltage value, and the operation of the driving voltage conversion unit when the voltage drop detection signal is given from the voltage monitoring unit. A power supply control unit that activates the auxiliary power supply unit while stopping is provided (claim 3).

In the invention thus constructed, the driving voltage converting section is provided with, for example, a capacitance component for voltage stabilization. Then, when the voltage monitoring unit detects a drop in the power supply voltage and outputs a voltage drop detection signal, the power supply control unit that receives this signal activates the auxiliary power supply unit, and the auxiliary power supply unit operates as the drive voltage conversion unit. A third power supply voltage is generated by using the electric energy stored in the provided capacitance and is supplied to the control means. As a result, the power supply time to the control means can be extended.

Further, in the above, the control voltage conversion unit and the drive voltage conversion unit are operated by the DC voltage converted from the AC voltage by the rectification unit, so-called DC.
Although it is a -DC converter, each of these voltage conversion units may be an AC-DC converter that inputs an AC voltage and outputs a predetermined DC voltage (claim 4).
With such a configuration, as the rectifying element and the smoothing capacitor for converting the AC voltage into the DC voltage, it is possible to use a relatively small capacity and a small component according to the specifications of each voltage conversion unit. Therefore, the device cost can be reduced.

The image forming apparatus according to the present invention is
When the voltage drop detection signal is given from the voltage monitoring unit, a termination process for bringing each unit of the device into a predetermined termination state is performed (claim 5).

In the invention thus configured, as described above, the power supply control unit stops the operation of the driving voltage conversion unit when the decrease in the power supply voltage is detected, and further the auxiliary power supply is provided as necessary. The power supply time to the control means is extended by activating the section. Then, during this period, the control means performs a predetermined termination process, so that there is no problem caused by a decrease in the power supply voltage during operation, which has occurred in the prior art.
A proper end state can be realized.

One of such end processes is a stop operation of the motor constituting the drive means (claim 6). By doing so, even if the motor is rotating when the power supply voltage drops, the rotation can be quickly and surely stopped. Then, by suppressing the consumption of electric energy by the driving means including the motor, the duration of power supply to the control means can be further extended.

The image forming apparatus according to the present invention is
In order to achieve the above-mentioned object, a storage medium for storing predetermined data is further provided, and the control means performs at least a predetermined write operation to the storage medium as the end processing (claim 7). ).

In the invention thus constructed, when the power supply voltage is lowered, the control means controls the total number of monochrome pages, for example, the total number of pages printed in monochrome, and the total number of colors, which is the total number of pages printed in color. Since the operation is stopped after writing the data indicating the usage status of each part such as the number of pages and the dot count value for each toner color, the device is used before the power supply voltage drops. Information about the state can be reliably stored.

Further, when the control means is writing to the storage medium at the time when the voltage drop detection signal is given from the voltage monitoring section, the control means, as the predetermined write operation, An operation of completing the writing of the data being written to the storage medium may be performed (claim 8).

In the invention configured as described above, only the data during the write operation is written when the power supply voltage is lowered, so that the time required for the end process can be shortened. As a result, the capacity for storing electrical energy or the capacity of the power storage unit can be reduced, and the cost of the device can be reduced.

Further, a cartridge detachable from the main body of the image forming apparatus may be further provided, and the storage medium may be disposed in the cartridge (claim 9).

In the invention thus constructed, when the power supply voltage drops, the control means writes data to be held by the cartridge, for example, data indicating the consumption of toner in the toner cartridge. Since the operation is stopped, it is possible to surely store the information on the usage state of the cartridge before the power supply voltage drops.

Further, some image forming apparatuses execute a power saving mode in which each unit of the apparatus is placed in a standby state as necessary to suppress power consumption. In such an image forming apparatus, it is desirable to restrict the input of the voltage drop detection signal from the voltage monitoring unit to the power supply control unit when the power saving mode is executed (claim 10). This power saving mode does not completely reduce the power supply voltage of the device to stop the device, but it is necessary to continue supplying the power supply voltage necessary for maintaining the standby state to the driving means. Therefore, even if a part of the power supply voltage drops due to the execution of the power saving mode and the voltage drop detection signal is output from the voltage monitoring unit, it is necessary to operate the driving voltage conversion unit. Therefore, in the present invention, when the power saving mode is executed, the input of the voltage drop detection signal to the power supply control unit is regulated to secure the power supply to the drive means.

The image forming apparatus according to the present invention is
In order to achieve the above object, the control means further includes a time counting unit that counts an elapsed time from the time when the power supply control unit stops the operation of the driving voltage conversion unit, and the power supply control unit is the time counting unit. When the elapsed time counted by the unit reaches a preset set time, the operation of the drive voltage conversion unit is restarted (claim 11).

In the invention thus constituted, the elapsed time from the time when the power supply control unit stops the operation of the driving voltage conversion unit is counted, and the counted elapsed time reaches the preset set time. Then, it means that the operation of the control voltage conversion section was continued, which means that the power supply voltage is restored.Therefore, by restarting the operation of the drive voltage conversion section, The operation can be restarted, and the usability of the device is improved.

Further, for the set time, when the supply of the AC voltage is stopped, the supply voltage to the control means is from the time when the operation of the drive voltage conversion section by the power supply control section is stopped. It is desirable to set the time longer than the time required until the operation guarantee voltage drops to a guaranteed value (claim 12). As a result, the fact that the elapsed time from the time when the power supply control unit stopped the operation of the driving voltage conversion unit has reached the set time means that the power supply voltage has been restored from the stop of the AC voltage supply. Therefore, the operation of the driving voltage converter is surely restarted.

If the control means is composed of a CPU, for example, the operation guarantee voltage may be a voltage at which the CPU is reset. Further, in the above-mentioned configurations of claims 11 and 12, instead of counting the elapsed time from the time when the power supply control unit stops the operation of the driving voltage conversion unit, the clock unit detects the voltage drop from the voltage monitoring unit. You may make it count the elapsed time from the time of giving a signal.

The image forming apparatus according to the present invention is
In order to achieve the above object, the control means further includes an instruction control unit that outputs an operation start instruction signal that instructs the operation start of the driving voltage conversion unit, and an error signal control unit that outputs a predetermined error signal. The power supply control section starts the operation of the drive voltage conversion section when the operation start instruction signal is given from the instruction control section.
The voltage monitoring unit outputs a voltage rise detection signal when the output voltage of the driving voltage conversion unit rises to the predetermined voltage value or more, and the error signal control unit includes the operation by the instruction control unit. The error signal is output when the voltage monitoring unit does not output the voltage rise detection signal before the preset standby time elapses from the output of the start instruction signal (claim 1).
3).

In the invention thus constructed, the operation of the drive voltage conversion section is started when the operation start instruction signal is given from the instruction control section, and the output voltage of the drive voltage conversion section is set to the predetermined value. When the voltage rises above the voltage value, the voltage rise detection signal is output. Here, when the voltage rise detection signal is not output from the voltage monitoring unit until the preset standby time elapses from the output time of the operation start instruction signal, the error signal is output, It becomes possible to notify the failure of the driving voltage conversion section and to perform processing for the failure, thereby improving the usability of the apparatus.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A. First Embodiment FIG. 1 is a diagram showing a first embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing the configuration of the power supply unit of the image forming apparatus of FIG. FIG. 3 is a block diagram showing the engine controller of this image forming apparatus. This image forming apparatus forms a full-color image by superposing four color toners of yellow (Y), magenta (M), cyan (C), and black (K), or uses only black (K) toner. Is a device that forms a monochrome image. In this image forming apparatus, when an image signal is given from an external device (not shown in FIG. 3) such as a host computer to a main controller (not shown in FIG. 3) of the control unit, the engine controller 1 is operated according to a command from the main controller. Controls each part of the engine unit EG to form an image corresponding to the image signal on the sheet S such as copy paper, transfer paper, paper and OHP transparent sheet.

In this engine section EG, seven units are provided: (a) photoconductor unit 2; (b) yellow developing unit 3Y; (c) magenta developing unit 3M; (d) cyan developing unit 3C; (e ) Black developing unit 3K; (f)
The intermediate transfer unit 4 and (g) fixing unit 5 are detachable from the apparatus body 6. Then, in a state where all the units 2, 3Y, 3M, 3C, 3K, 4 and 5 are attached to the apparatus main body 6, as shown in FIG. 1, the photoconductor 21 of the photoconductor unit 2 is moved in the arrow direction of FIG. While rotating to D1, along the rotation direction D1 around the photoconductor 21, the charging unit 22, the developing units 3Y, 3M, 3C,
The rotary developing unit 3 and the cleaning unit 23, each of which is made of 3K, are arranged.

Seven units 2, 3Y, 3M, 3C, 3
Among K, 4, and 5, the photoconductor unit 2 contains the photoconductor 21, the charging unit 22, and the cleaning unit 23.
These can be integrally attached to and detached from the apparatus body 6. A charging bias is applied to the charging unit 22 to uniformly charge the outer peripheral surface of the photoconductor 21.

Further, the photoconductor unit 2 is provided with a cleaning unit 23 on the upstream side of the charging unit 22 in the rotation direction D1 of the photoconductor 21, and remains attached to the outer peripheral surface of the photoconductor 21 after the primary transfer. Scrape off any toner that is still on.
In this way, the surface of the photoconductor 21 is cleaned.

As shown in FIG. 3, the photoconductor unit 2 thus constructed has a serial EEPROM 71 for storing data indicating the remaining life of the unit 2.
When the photoconductor unit 2 is attached to the apparatus body 6, the apparatus body 6 is connected via a connector (not shown).
Is electrically connected to the engine controller 1 to transfer data to and from the engine controller 1 and manage consumables of the photoconductor unit 2. As for the other units 3Y, 3M, 3C, 3K, 4 and 5, serial EEPROMs 72 to 77 for storing various data are attached similarly to the photoconductor unit 2.
It is electrically connected to the engine controller 1 of the apparatus body 6 in the unit mounted state, transfers data with the engine controller 1, and manages consumables of the unit.

In this image forming apparatus, as shown in FIG. 1, the exposure unit 8 irradiates the outer peripheral surface of the photoconductor 21 charged by the charging unit 22 with the laser beam L. The exposure unit 8 scans and exposes the laser light L on the photoconductor 21 according to the image signal from the engine controller 1 to form an electrostatic latent image on the photoconductor 21 corresponding to the image signal.

The electrostatic latent image thus formed is toner-developed by the developing unit 3. That is, in this embodiment, as the developing unit 3, the developing unit 3K for black, the developing unit 3C for cyan, and the developing unit 3 for magenta are used.
A developing unit 3Y for M and yellow is rotatably provided around the axis. The developing units 3K, 3C, 3M, and 3Y are rotationally positioned and selectively positioned at the contact or separation position with respect to the photoconductor 21 to develop a DC component or a DC component superimposed with an AC component. A bias is applied to apply the selected color toner to the surface of the photoconductor 21. As a result, the electrostatic latent image on the photoconductor 21 is visualized in the selected toner color.

The toner image developed in the developing section 3 as described above is primarily transferred onto the intermediate transfer belt 41 of the intermediate transfer unit 4 in the primary transfer region TR1. That is, the intermediate transfer unit 4 includes an intermediate transfer belt 41 that is wound around a plurality of rollers, and a drive motor 51 (FIG. 3) that rotationally drives the intermediate transfer belt 41, and transfers a color image onto the sheet S. In this case, the toner images of the respective colors formed on the photoconductor 21 are superimposed on the intermediate transfer belt 41 to form a color image. On the other hand, when the monochrome image is transferred to the sheet S, the image is formed on the photoconductor 21. Only the formed black toner image is transferred onto the intermediate transfer belt 41 to form a monochrome image.

The image thus formed on the intermediate transfer belt 41 is secondarily transferred onto the sheet S taken out from the cassette 9 in a predetermined secondary transfer region TR2. Further, the sheet S on which the image is thus formed is conveyed to the discharge tray portion provided on the upper surface of the apparatus main body 6 via the fixing unit 5.

Next, the power supply section of this image forming apparatus will be described with reference to FIG. As shown in FIG. 2, this image forming apparatus operates with an AC voltage (100V) from a commercial power supply (AC power supply). The power supply unit includes a rectifying unit 100 including a bridge rectifying circuit 101 and a smoothing capacitor 102, a driving DC-DC converter 103 that supplies electric power to the engine unit EG, and a controller DC-DC that supplies electric power to the engine controller 1. It is composed of a converter 106, a backflow prevention diode 104, and a capacitor 105.

In this power supply unit, an AC voltage of 100 V input from the outside of the device is converted into a DC voltage V1 by the bridge rectifier circuit 101 by the diode bridge and the smoothing capacitor 102. And drive DC-D
The C converter 103 converts this DC voltage V1 into a voltage V2 (for example, 24V) which is a drive voltage of the engine section EG and supplies it to each section of the engine section EG.

Further, the output voltage V2 of the driving converter 103 is the voltage monitor terminal V of the engine controller 1.
It is also input to M, and the engine controller 1 monitors this voltage V2 and detects a decrease in the AC input voltage based on the change in the voltage V2.

Then, the driving DC-DC converter 10
The engine control signal EC and the power saving mode setting signal PS from the engine controller 1 are input to 3,
These signals control its start / stop and output voltage. These signals EC and PS are transmitted to the engine section E.
It is also input to G, and permission / prohibition control is also performed on the operation of the engine section EG. Note that these signals EC
The functions of PS and PS will be described in detail later.

On the other hand, the output voltage V1 of the rectifying section 100 is also input to the controller DC-DC converter 106 via the diode 104 and the capacitor 105. This controller DC-DC converter 106
Converts the input voltage V1 into a voltage V3 (for example, 5 V) which is a drive voltage of the engine controller 1 and supplies the voltage V3 to the engine controller 1. And the capacitor 105
In the diode 104, electric charges are accumulated by the voltage application from the rectifying unit 100.
It prevents the backflow to zero.

Next, the structure of the engine controller 1 will be described with reference to FIG. This engine controller 1 functions as the control means of the present invention,
The operation control of each part of the engine part EG is performed according to a control command from the main controller (omitted in FIG. 3), the power supply voltage is monitored, and the engine part E is monitored based on the change.
The start / stop control of G and the power supply unit is performed. As shown in FIG. 3, the engine section EG includes, as drive means, a drive motor 52 that rotationally drives the rotary developing section 3, a drive motor 53 that conveys the sheet S, and the like, in addition to the drive motor 51.

To the CPU 11 of the engine controller 1, a ROM 12 for storing various processing programs for controlling the engine section EG and other data, and a RAM 13 for temporarily storing various data are connected. In the following, the same designation will be used for each signal line (or a terminal connected to the signal line) of the engine controller 1 and a signal name transmitted by the signal line (for example, the engine controller 1
EC signal output from the EC port).

The CPU 11 also uses the serial I / F (interface) 15 to connect the serial EEPROM 1
4 is connected. The serial EEPROM 14 uses each part of the apparatus, such as the total number of monochrome pages for which monochrome printing has been performed, the total number of color pages for which color printing has been performed, and the dot count value for each toner color. Various data indicating the state are stored, and are appropriately updated according to the usage status of the device.

In addition to the serial EEPROM 14 inside the engine controller 1, the CPU 11 also has a serial I / F for the serial EEPROMs 71 to 77 provided in the units 2, 3Y, 3M, 3C, 3K, 4, and 5.
Each serial EEPROM is connected via 15
14 and 71 to 77, data can be transferred to and from the serial EEPROM 1 via the output port 16.
The chip select signal CS can be input to 4, 71 to 77.

Further, the engine controller 1 is provided with a voltage monitoring circuit 17. The voltage monitoring circuit 17
When it is detected that the power supply voltage V3 supplied from the controller DC-DC converter 106 to the engine controller 1 is lower than a predetermined voltage, a reset signal RESET indicating that is output to the CPU 11 and the peripheral devices 15 and 16. Specifically, the reset signal RESET is changed from H level to L level. On the other hand, the output voltage V of the driving DC-DC converter 103 input to the voltage monitor terminal VM
When it is detected that 2 is lower than the predetermined voltage, the voltage drop detection signal PD indicating that is output. Specifically, when the voltage V2 is above a predetermined value, it is at H level, and when it is below the predetermined value, it is at L level
And outputs the voltage drop detection signal PD.

The voltage drop detection signal PD is input to the OR circuit 18 together with the interrupt enable signal IE which is output from the CPU 11 and becomes L level when the interrupt generated by the drop of the voltage V2 is enabled. The interrupt request signal NMI, which is a logical sum output, is input to the unconditional interrupt terminal NMI of the CPU 11. That is, when the interruption is permitted by the interruption permission signal IE, when the decrease of the power supply voltage V2 is detected, the interruption request signal NMI becomes the L level and an interruption occurs in the CPU 11, and the CPU 11 performs a predetermined interruption process. Run. On the other hand, when the interrupt is prohibited, the interrupt request signal NMI maintains the H level even if the voltage V2 drops and the voltage drop detection signal PD becomes L, and the interrupt does not occur.

Next, the operation of the image forming apparatus when the AC input voltage drops due to a power failure or user operation will be described with reference to FIG. FIG. 4 is a timing chart showing the operations of the power supply unit and the engine controller 1 when the AC voltage drops.

Here, in the apparatus which was in the normal operation state with the AC voltage being normally applied, the time t0 shown in FIG.
First, consider the case where the AC power supply voltage drops to 0V due to a power outage or a user turning off the power supply.

In the normal operation state, the state of each signal in each part of the engine controller 1 is as follows.
That is, a voltage drop detection signal PD indicating that V2 has dropped: an interrupt enable signal I for enabling an interrupt associated with the H level voltage drop
E: Interrupt request signal to L level CPU 11 N: H level Control signal for engine section EG and power supply section EC: H level Power saving mode setting signal PS: L level System reset signal RESET: H level.

When the AC input voltage decreases at time t0 shown in FIG. 4, charging of the smoothing capacitor 102 is stopped and the output voltage V1 of the rectifying unit 100 gradually decreases. Along with this, the output voltage V2 of the drive converter 103
Also starts to drop from the original 24V. When the voltage V2 falls below a predetermined voltage (here, 21.6V corresponding to 90% of the normal operating voltage 24V), the voltage monitoring circuit 17 detects this and outputs the voltage drop detection signal PD at the normal time. Is changed from H level to L level (time t1). for that reason,
The input signal to the NMI terminal of the CPU 11 becomes L level, which causes an unconditional interrupt in the CPU 11.

When this unconditional interrupt occurs, the CPU
11 starts the termination process described below (time t
2). The ending process is the following two items. That is, (1) The engine control signal EC is set to the L level via the output port 16.

(2) If writing is being controlled to any of the serial EEPROMs 14 and 71 to 77 through the serial I / F 15, only that data is continuously written, and when the writing is completed, the data is written to the serial EEPROM. Stop access.

At this time, the engine control signal EC of (1) above
Changes to the L level, the engine section EG (for example, the drive motors 51, 52, 53, etc.) and the drive DC-
The DC converter 103 is configured to stop its operation. Therefore, the output voltage V2 of the driving DC-DC converter 103 rapidly decreases as shown in FIG. On the other hand, when the driving DC-DC converter 103 stops operating, the smoothing capacitor 102 drives the driving DC-D.
The current flowing to the C converter 103 stops. Therefore, after time t2, as shown in FIG. 4, the output voltage V1 of the rectifying unit 100 gradually decreases.

Thus, the driving DC-DC converter 1
When 03 stops its operation, DC-D for controller
The C converter 106 continues the voltage output using the electric charge stored in the smoothing capacitor 102. Then, as the terminal voltage of the smoothing capacitor 102 decreases, the voltage V3
Starts decreasing (time t4), and the voltage monitoring circuit 17 detects this voltage decrease and outputs the reset signal RESET. Specifically, the reset signal RESET is changed from H level to L level. As a result, the entire engine controller 1 is reset and its operation is stopped.

Even when the current consumption of the engine section EG is large at the time when the AC voltage drops and the voltage V1 drops rapidly due to the progress of the discharging of the smoothing capacitor 102, the charge is accumulated in the capacitor 105. This charge is supplied to the driving DC- by the backflow prevention diode 104.
Since it does not flow to the DC converter 103, the controller DC-DC converter 106 can continue to supply the voltage to the engine controller 1 by using the charge accumulated in the capacitor 105.

On the other hand, the present invention is not implemented, that is,
Without providing the diode 104 and the capacitor 105, the driving DC-DC converter 103 even if the AC voltage drops
When the operation of No. 1 is not stopped, the output voltage V1 of the rectifying unit 100 rapidly decreases as shown by the dotted line in FIG. Then, due to the decrease in the input voltage, the controller DC-D
The output voltage V3 of the C converter 106 also starts to drop earlier as shown by the dotted line in FIG. 4, and the voltage monitoring circuit 17 outputs the reset signal RESET at time t3, at which time the engine controller 1 stops its operation.

As described above, according to the present invention, the power supply time to the engine controller 1 is extended during the period of t4 to t3.
Meanwhile, the engine controller 1 can maintain its function.

Here, the time required to write the serial EEPROM is on the order of several ms. Then, as described above, the operation of the engine unit EG and the power supply unit thereof is stopped to suppress the consumption of the electric charge stored in the smoothing capacitor 102, and the electric charge is reduced to the controller DC-D.
By allocating the power to the C converter 106, it is possible to extend the operation time of the engine controller 1 for several ms or longer. Thus, the end process for stopping the operation including the above-mentioned write process can be surely performed during this period.

By the way, this image forming apparatus has a power saving mode for reducing power consumption during standby. In this image forming apparatus, when there is a mode switching request from the user or an external device, or when there is no access from the user or the external device for a predetermined period of time, the power saving mode is executed and the respective parts of the device are put in a standby state. Transition. Then, if there is an access from the user or an external device, it immediately shifts to the normal operation state.

The operation of this power saving mode will be described with reference to FIG. FIG. 5 is a timing chart showing the operation of the image forming apparatus of this embodiment in the power saving mode. When the power saving mode is set by the main controller, the CPU 11 sets the interrupt permission signal IE to the H level to prohibit the interrupt (time t
5) The power saving mode setting signal PS of H level is output through the output port 16 (time t6). This signal PS causes the engine section EG to stop its operation and enter a standby state. The driving DC-DC converter 103 uses the output voltage V2 as a standby voltage of 50% of the normal operating voltage.
It changes to 12V which is equivalent to. As a result, V2 gradually decreases, and the voltage drop detection signal PD becomes L at the time when it falls to 21.6V which is 90% of the normal operation voltage (time t7), but the interrupt enable signal IE is at H level, so the CPU
The input signal to the NMI terminal 11 is maintained at the H level. Therefore, it is not interrupted by the voltage drop,
The operation of the drive converter 103 is not completely stopped as in the case of a voltage drop due to a power failure or the like, and the standby voltage is maintained.

Here, if the interrupt enable signal IE is not used, an interruption to the CPU 11 occurs due to the decrease in the supply voltage V2 to the engine section EG accompanying the shift to the power saving mode. Since the driving DC-DC converter 103 is stopped by the stop control of No. 3, it becomes impossible to maintain the standby voltage.

The supply voltage to the engine section EG is 5
Since it has decreased to 0%, the power consumption in the engine part EG can be suppressed lower than in the normal operation state. In this way, the power saving mode is realized in which the power consumption of the device is suppressed while maintaining the minimum functions.

Then, if there is an access from the user or an external device, the CPU 11 sets the power saving mode setting signal PS to the L level to cancel the power saving mode (time t8),
In response to this, when the output voltage V2 of the driving DC-DC converter 103 rises to 24V again (time t9), the interrupt control signal IE is set to the L level to permit the interrupt, and the device returns to the normal operation mode (time t10). ).

Now, considering the case where the AC voltage drops when the device is in the power saving mode, at this time, the engine section EG has already stopped its operation and is in the standby state, indicating the usage state of the device. At this time, there is no need to stop the engine part EG or write data because no data change occurs. Therefore, in addition to the power saving mode setting, the engine section EG and each EEPROM 14, 7 are
By prohibiting access to 1 to 77, it can be said that a power failure countermeasure is taken in the power saving mode. Therefore, when the device is in the power saving mode, even if the supply of the AC voltage is stopped, it is not necessary to perform a special termination operation or a power failure countermeasure.

B. Second Embodiment A second embodiment of the image forming apparatus of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a block diagram showing the configuration of the power supply unit of this image forming apparatus. Also, FIG.
FIG. 4 is a timing chart showing the operation of the power supply unit of this image forming apparatus when the AC voltage drops. In this embodiment, the configuration of the power supply unit is slightly different from that of the first embodiment, and the other configurations and basic operations are the same as those of the first embodiment. Are denoted by the same reference numerals and the description thereof will be omitted. Here, the configuration and operation of the power supply unit of the present embodiment will be described.

In this embodiment, the controller DC-
The input side diode and the capacitor of the DC converter 106 are not provided, and the driving DC-DC converter 103 and the controller DC-DC converter 106 are not provided.
And are connected in parallel to the output of the rectification unit 100 (bridge rectification circuit 101 and smoothing capacitor 102).
A capacitor 107 and a regulator 108 are connected to the output side of the driving DC-DC converter 103. The regulator 108 is start / stop controlled by the engine control signal EC and the power saving mode setting signal PS output from the engine controller 1, and outputs the output voltage V6 of the controller DC-DC converter 106.
The voltage V7 that is almost the same as

In this embodiment, the capacitor 107 is
Although it has a function of accumulating charges for the operation of the regulator 108 described later, it is generally used to insert a capacitor in the output part of the power supply circuit for stabilizing the output, for this purpose. No special parts need to be added. However, as will be described later, since it is necessary to operate the controller DC-DC converter 106 by using the electric charge accumulated in this capacitor at the time of power failure, it is desirable that the capacity is relatively large.
In this case, since the capacitor 107 is connected to the output of the driving DC-DC converter 103, the rectifying unit 100
It is possible to use a capacitor having a lower breakdown voltage than that of the capacitor 102 used for.

The output of the regulator 108 and the output of the controller DC-DC converter 106 are connected via diodes 110 and 109,
The higher one of the two output voltages is supplied to the engine controller 1, while the output currents thereof are prevented from flowing into the output parts of the two.

In this device, as shown in FIG.
When the AC voltage decreases at 11 and the rectified voltage V4 decreases, the output voltage V5 of the driving DC-DC converter 103 starts decreasing. When the voltage V5 drops to 21.6 V (time t12), the voltage monitoring circuit 17 detects this and outputs the L level voltage drop detection signal PD. As a result, the interrupt request signal NMI becomes L and an interrupt occurs, and the CPU 11 sets the engine control signal EC to L level (time t13). In response to the change of the engine control signal EC to the L level, each part of the apparatus operates as follows.

(1) The driving DC-DC converter 103 stops its operation. As a result, the smoothing capacitor 102
To the driving DC-DC converter 103 stops. Therefore, the decrease of the terminal voltage V4 of the smoothing capacitor 102 after the time t13 becomes gentle.

(2) The engine part EG stops its operation. This reduces the inflow of current into the engine section EG. Therefore, the capacitor 107 after the time t13
The decrease of the terminal voltage V5 becomes slow.

(3) The regulator 108 is activated to start outputting the voltage V7 at time t13. As a result, the engine controller 1 operates with two power supplies, that is, the electric charges of the smoothing capacitor 102, and is a controller DC.
-The voltage is supplied from both the DC converter 106 and the regulator 108 that operates using the charge of the capacitor 107, and in that operation, the voltage V4 and the voltage V5 decrease, and the controller DC-DC converter 106 and It is possible to continue until both regulators 108 become inoperable (time t15).

On the other hand, at the time t13, if the operations (1) to (3) are not performed, the output voltage V4 of the rectifying section 100 becomes
As shown by the dotted line in FIG. 7, it drops rapidly. Along with this, the controller DC-DC converter 10
The output voltage V6 of 6 also starts to decrease earlier, and the reset signal RESET is output from the voltage monitoring unit 17 at time t14 and the engine controller 1 stops. That is, according to the present invention, the power supply time to the engine controller 1 is extended between t15 and t14.

As described above, in this embodiment, when the AC voltage decreases, the engine section EG and the driving DC-DC
By stopping the operation of the converter 103 and activating the regulator 108, the power supply time to the engine controller 1 can be extended.

In this embodiment, the power saving mode can be executed as in the first embodiment. In the power saving mode of this embodiment,
Since the voltage supply from the AC power supply continues, it is not necessary to start the regulator 108, and only the engine section EG and the driving DC-DC converter 103 have to be in the standby state.

C. Third Embodiment In the above-described embodiment, each rectifying unit 100 is provided, and each D
The C-DC converters 103 and 106 voltage-convert the rectified output voltage to obtain the respective output voltages, but it is also possible to adopt a configuration in which the AC voltage is directly input using each converter as the AC input. A third embodiment of the image forming apparatus according to the present invention configured as described above will be described with reference to FIG.

FIG. 8 is a block diagram showing the structure of the power supply unit of the image forming apparatus of this embodiment. The power supply unit of this embodiment is different from the power supply unit of the second embodiment shown in FIG. 6 only in the way of inputting a commercial AC voltage, and other configurations and the operation of the engine controller 1 are basically the same. Therefore, the same components will be denoted by the same reference numerals and description thereof will be omitted, and only different portions will be described here.

This image forming apparatus is not provided with a rectifying unit composed of a bridge rectifying circuit and a smoothing capacitor, and commercial AC voltage introduced from the outside is used for driving and controller AC-DC converters 111 and 112. Is entered directly into. Then, these converters 111 and 112 convert the AC voltage into predetermined DC output voltages V8 (for example, 24V) and V9 (for example, 5V) and output them, and supply them to the engine section EG and the engine controller 1, respectively. Further, the ground lines are connected on the respective output sides in order to provide the ground potential which is the operation reference while ensuring the insulation from the AC circuit.

In this embodiment, as in the previous embodiment, when the AC voltage drops, the operation of the engine section EG and the converter 111 is stopped and the regulator 10 is operated.
By activating 8, the power supply time to the engine controller 1 can be extended. In this case, the controller AC-DC converter 112 operates to continue the output by using the charges accumulated in the capacitive component included as the circuit element.

Further, in this embodiment, it is not necessary to provide a large-capacity diode or smoothing capacitor as the rectifying unit, and a rectifying circuit corresponding to each load may be adopted. Therefore, the size and cost of the device can be reduced.

It is needless to say that the power saving mode can be executed in this embodiment as in the previous embodiment.

D. Fourth Embodiment In each of the above-described embodiments, a case has been described in which the AC input voltage is turned off due to a power failure, an operation mistake, or the like. The operation when the input voltage is turned off for a short time will be described.

FIG. 9 is a block diagram of a power supply unit of a fourth embodiment of the image forming apparatus according to the present invention, and FIG. 10 is a block diagram of an engine controller of the fourth embodiment. The internal configuration of this image forming apparatus is the same as that of the first embodiment shown in FIG. 1. In FIGS. 9 and 10, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 9, a commercial AC power source 107 and a power switch 108, which are not shown in FIG. 2, are shown, and in FIG. 10, an external device (for example, a personal computer or a PC) 200, which is not shown in FIG. 3, is shown. Also, a main controller 201 is shown, and the image forming apparatus of the fourth embodiment includes a PC as in the first embodiment.
A print command signal including an image signal is input from the image forming apparatus 200 via the main controller 201.
The CPU 11 of the engine controller 1 forms an image according to the image signal by controlling the operation of each unit of the engine unit EG based on the print command signal.

The voltage monitoring circuit 17 is, for example, a constant voltage power source 1
71, voltage dividing resistors 172 and 173, and a comparator 174. One input terminal of the comparator 174 is connected to the connection point of the voltage dividing resistors 172 and 173, and the other input terminal of the comparator 174 is connected to the voltage monitor terminal VM. The output voltage of the constant voltage power supply 171 is the voltage dividing resistor 1
The voltage is divided by 72 and 173, and the divided voltage value Vt is input to the comparator 174. And the comparator 1
74 outputs a voltage drop detection signal PD which becomes H level when the output voltage V2 of the driving DC-DC converter 103 is V2 ≧ Vt and becomes L level when V2 <Vt. The partial pressure value V
As in the first embodiment, t is set to Vt = 21.6V (90% of 24V), and the voltage monitoring circuit 17
The same function as that of the first embodiment is achieved. The circuit configuration of the voltage monitoring circuit 17 is an example, and the present invention is not limited to this.

The operation display panel 31 is provided at a proper place on the surface of the apparatus main body 6 (FIG. 1) of the image forming apparatus, and is operated by the user and a display section composed of, for example, a liquid crystal display panel for displaying a message to the user. And an operation section including operation keys such as a mode setting key. In addition to the function of the output port 16 (FIG. 3), the input / output port 16A outputs a signal for display on the operation display panel 31, and also outputs a signal according to the operation applied to the operation display panel 31 to the CPU 11. Has a function to input.

The CPU 11 has the following functions: When the output voltage V2 of the driving DC-DC converter 103 drops below a predetermined voltage Vt, the operation of the driving DC-DC converter 103 is stopped and a power failure occurs. A function of notifying the PC 200 of the effect via the main controller 201.

The counting of the elapsed time is started from the time when the operation of the driving DC-DC converter 103 is stopped, and when the preset time T0 has elapsed, the driving DC-DC converter 103
The operation of the DC converter 103 is restarted, and the fact that the operation is restarted is notified via the main controller 201.
A function to notify the C200.

The counting of the elapsed time T is started from the time when the operation of the drive DC-DC converter 103 is started (the time when the engine control signal EC is switched from the L level to the H level).
Even if the preset standby time T10 has elapsed, the output voltage V
A function of sending an error signal to the PC 200 via the main controller 201 when 2 does not rise to the predetermined value Vt.

When the power is turned on, it has a function as a selection control section for selecting whether or not the driving DC-DC converter 103 is made to stand by without operating. This selection is performed, for example, when a selection key provided on the operation display panel 31 is operated by the user, a message prompting the selection is displayed on the operation display panel 31, and the user operates the display. When it is selected to put the driving DC-DC converter 103 on standby when the power is turned on, the fact is stored in the serial EEPROM 14. When the power switch 108 is turned on, the serial EEPROM
When it is stored that the content stored in M14 is fetched and the driving DC-DC converter 103 is on standby, the power supply control unit has a function of stopping the operation of the converter 103.

The set time T0 in the above function is the time T1 required for the output voltage V3 of the controller DC-DC converter 106 to fall below the reset voltage (operation guarantee voltage) Vr of the CPU 11 from the time when the AC input voltage is off. , DC-D for driving from the time of turning off the AC input voltage
When the time until the operation of the C converter 103 is stopped is T2, T0> T1-T2 is set. That is, to explain with reference to FIG. 4 described above, T1 = t2-t0 T2 = t4-t0 T0> T1-T2 = t4-t2.

Here, the completion of the counting of the set time T0 means that the operation of the controller DC-DC converter 106 is continued due to the return of the AC input voltage, that is, the decrease of the AC input voltage causes the commercial AC power supply 107 to be reduced.
Due to the so-called momentary power failure or momentary voltage drop of
This means that the off time of the AC input voltage was short.

Next, referring to FIGS. 11 to 14, the CPU
The operation of the above function of 11 will be described. Figure 11
Is a flowchart showing an example of the operation procedure, and FIG.
It is a flowchart which shows the subroutine of step # 22 of 1. 13 and 14 are timing charts showing changes in each voltage and each signal, FIG. 13 shows a case where the AC input voltage does not recover from OFF, and FIG. 14 shows a case where the AC input voltage recovers from OFF. ing.

The routine of FIG. 11 is repeatedly executed at a predetermined sampling cycle (for example, 10 msec). In step # 10 in the figure, first, it is determined whether or not the output voltage V2 of the driving DC-DC converter 103 input to the voltage monitor terminal VM has fallen below a predetermined value Vt. Here, for example, when the AC input voltage is cut off due to a power failure at time t20 in FIGS. 13 and 14, the driving DC-DC converter 103 is accompanied by a decrease in the output voltage V1 of the rectifying unit 100.
Although the output voltage V2 of No. 2 starts decreasing, if V2 ≧ Vt in step # 10 (NO in step # 10), this routine is ended.

Then, at time t21, when V2 <Vt (YES in step # 10 of FIG. 11), the voltage drop signal PD is switched to the L level, and the ending process described in the first embodiment is executed. Later (step # 12),
At time t22, the driving DC-DC converter 10
3 is stopped (step # 14), counting of the elapsed time T is started (step # 16), and P
The C200 is notified that there is a power outage (step #
18).

Next, it is determined whether or not the counted elapsed time T has reached the set time T0 (step # 2
0) and T <T0 (NO in step # 20), the determination in step # 20 is repeated. Here, when the AC input voltage is turned off due to a long-term power failure or the user turning off the power switch 108, the AC input voltage does not recover, and therefore, as shown in FIG. When the output voltage V3 of the DC-DC converter 106 becomes less than the reset voltage (operation guarantee voltage) Vr of the CPU 11, the operation of the CPU 11 is stopped without reaching T ≧ T0.

On the other hand, when the turning off of the AC input voltage is caused by the so-called momentary power failure or momentary voltage drop of the commercial AC power source 107, as shown in FIG. 14, for example, at time t2.
At 4, the AC input voltage is restored. As a result, the rectifying unit 100
Of the controller DC-DC converter 106 is maintained at 5V without lowering below the reset voltage Vr, whereby the counting of the elapsed time T is continued. #
The determination of 20 is repeated.

Then, at time t25 in FIG. 14, T ≧
When T0 is reached (YES in step # 20), drive D
The operation of the C-DC converter 103 is restarted (step # 22). This subroutine will be described with reference to FIG. 12. First, the engine control signal EC is switched from the L level to the H level (step # 30), and then the counting of the elapsed time T from this switching time point is started (step # 30). # 32), and then the driving DC-DC converter 1
It is judged whether or not the output voltage V2 of No. 03 has reached the predetermined value Vt (step # 34).

If V2 <Vt (step # 3)
4 is NO), it is determined whether or not the elapsed time T has reached the waiting time T10 (step # 36), and if T <T10 (NO in step # 36), the process returns to step # 34,
Steps # 34 and # 36 are repeated.

By the time T ≧ T10 (NO in step # 36), V2 ≧ Vt (step # 34).
YES at time t26 in FIG. 14), the voltage drop detection signal PD
Is switched from the L level to the H level (step #
38), the routine ends.

On the other hand, until V2 ≧ Vt (step #
If NO in step 34) and T ≧ T10 (YES in step # 36), it is determined that the drive DC-DC converter 103 has a failure, an error flag is set (step # 40), and this routine is executed. finish.

Returning to FIG. 11, in step # 24,
If the signal indicating the recovery from the power failure state or the error flag is set, the error signal is output to the PC 200 via the main controller 201 (step #
24) and terminates this routine.

Next, referring to FIGS. 15 to 17, the CPU
The operation of the above function of 11 will be described. Figure 15
Is a flow chart showing a selection procedure, FIG. 16 is a flow chart showing an operation procedure when the power is turned on, and FIG. 17 is a flow chart showing an operation procedure when a print command signal is input.

The routine of FIG. 15 is repeatedly executed at a predetermined sampling cycle (for example, 10 msec). In step # 50 of the figure, first, it is determined whether or not the selection key has been operated. When it is determined that the selection key has been operated (YES in step # 50), whether or not the drive DC-DC converter 103 does not operate and waits on the display unit of the operation display panel 31 when the power is turned on. A message prompting selection is displayed (step # 52). Next, for example, operation data indicating that the user is on standby is fetched (step # 54), and the setting content corresponding to the operation data is stored in the serial EEPROM 14 (step # 56).

The routine of FIG. 16 is executed only when the power is turned on. In step # 60 of the figure, first, when the power switch 108 is turned on, the drive DC-DC converter 103 and the controller DC-DC converter 106 start operating, and the controller DC-DC is started.
Power is supplied to the CPU 11 via the converter 106, and predetermined initial processing such as initialization of the RAM 13 is executed (step # 60). Then serial EE
The setting contents stored in the PROM 14 are fetched and it is determined whether or not the driving DC-DC converter 103 is set to stand by without operating (step # 62), and it is set to stand by. If not, this routine is terminated and the process proceeds to the main routine.

On the other hand, the driving DC-DC converter 103
Is set to stand by without operating (YES in step # 62), the driving DC-DC converter 1
The operation of 03 is stopped (step # 64), and the process proceeds to the main routine.

The routine of FIG. 17 is repeatedly executed at a predetermined sampling cycle (for example, 10 msec). In step # 70 of the figure, first, the main controller 20
When a print command signal is input from the PC 200 via 1 (YES in step # 70), it is determined whether the drive DC-DC converter 103 is on (step # 7).
2) If it is not on (NO in step # 72), the engine control signal EC is switched to the H level to drive DC.
-DC converter 103 is turned on (step # 7
4) The routine is finished.

As described above, according to the fourth embodiment, the elapsed time T from the time when the operation of the driving DC-DC converter 103 is stopped is counted, and when the elapsed time T reaches the set time T0, Since it is determined that the AC input voltage is restored and the operation of the driving DC-DC converter 103 is restarted, the AC input voltage may be decreased due to an instantaneous power failure or an instantaneous voltage drop of the commercial AC power supply 107. , If the AC input voltage recovers in a short time, the operation of the device can be resumed.
The usability of the device can be improved.

According to this embodiment, the driving DC-
When the operation of the DC converter 103 is started, the elapsed time T from the operation start instruction time point is counted, and if the output voltage V2 does not reach the predetermined value Vt even if the elapsed time T reaches the standby time T10, the drive is performed. DC-DC converter 1
03 failure, and an error signal to that effect is sent to the PC200.
Since it is sent to the user, the usability of the device can be improved by notifying the user of the PC 200.

Further, according to the present embodiment, it is possible to select whether or not the driving DC-DC converter 103 is made to stand by without operating when the power is turned on, so that the usability for the user can be improved. For example, when the user's usage mode is such that the image forming operation is not performed immediately when the power switch 108 is turned on, the driving DC-D
If the C converter 103 is set to stand by without operating, power consumption can be reduced without hindering the use of the device.

The procedure of FIG. 12 is not limited to step # 22 of FIG. 11, and for example, when the power is turned on, when returning from the power saving mode of FIG. It can be applied when the operation of the DC converter 103 is started. Accordingly, it is possible to detect a failure of the driving DC-DC converter 103 at any operation start point.

Further, in the present embodiment, the structure of the power supply unit is shown in FIG. 9, but the structure is not limited to this, and the structure shown in FIGS. 6 and 8 may be used. Further, although the elapsed time is counted by the CPU 11, a timer IC is separately provided,
You may make it count by this. Further, instead of providing the selection key on the operation display panel 31, it may be determined that the operation of the selection key is performed when a plurality of existing operation keys such as a mode setting key are simultaneously operated. Further, in step # 70 of FIG. 17, it is determined whether or not a print command signal is input, but in the case of a copying machine, for example, it may be determined whether or not a user operation is performed. .

E. In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, in each of the above-described embodiments, the voltage monitor terminal VM of the engine controller 1 is connected to the output terminal of the driving converter, and the voltage monitoring circuit 17 detects a decrease in the 24V output voltage of this converter. However, in addition to this, a configuration in which a power failure is detected by monitoring the output voltage of the rectification unit 100 may be used, and further, a configuration in which an AC voltage is directly monitored may be used. It suffices that at least the configuration can detect the decrease in the input voltage before the power supply voltage supplied to the engine controller 1 decreases.

However, in order to directly monitor the AC voltage, a structure for ensuring the insulation between the AC circuit and the DC circuit is necessary, and the output voltage of the rectifying section 100 has a large pulsation, so that the voltage drop is caused. It is necessary to devise some means to accurately detect. On the other hand, in the configuration for monitoring the output voltage of the driving converter as in the present embodiment,
Since the voltage is stabilized, it is easy to detect the voltage drop.As described above, the interrupt due to the voltage drop is prohibited when the power saving mode is executed. The voltage can be set freely.

Further, in each of the above-described embodiments, when the power saving mode is executed, the supply voltage to the engine section EG is set to 12V, which is 50% of the normal operating state, and the minimum power supply to the engine section EG is continued, Although the quick return to the operation mode and the reduction of power consumption are achieved, the voltage supplied to the engine section EG in the power saving mode may be a voltage other than this, for example, the output of the drive converter may be changed. It may be completely stopped and set to 0V. At this time, the power consumption during standby can be further reduced, and the signal line PS for setting the power saving mode can be omitted to switch between the normal operation mode and the power saving mode by the on / off operation of the drive converter by the engine control signal EC. It is possible to switch. However, at this time, the operation of the engine part EG is completely stopped, and the time required for returning to the normal operation mode and warming up each part of the device becomes long. Therefore, regarding the supply voltage to the engine part EG in the power saving mode, , It must be decided according to the specifications required for the device.

Further, in each of the above embodiments, 24V for driving the engine section EG and 5V for driving the controller.
Although two types of power supply voltage are used, the power supply voltage of the device may be other voltage, or a device using three or more types of voltage.

Further, in FIG. 2 of the first embodiment,
When the capacities of the capacitors 102 and 105 are C1 and C2, respectively, and the output rated currents of the converters 103 and 106 are A1 and A2, respectively, set (V2 · A1 / C1) >> (V3 · A2 / C2). You may As a result, the operating time of the controller DC-DC converter 106 can be reliably made longer than the operating time of the drive DC-DC converter 103.

Although the EEPROM is used in each of the above-described embodiments, other nonvolatile memory such as a ferroelectric memory (Ferroelectric RAM) may be used instead of the EEPROM.

[0123]

As described above, according to the present invention, the operation of the driving voltage conversion unit is controlled when the AC power supply voltage input to the device is lowered due to a power failure of the AC power supply system or a user turning off the power supply. On the other hand, the control voltage conversion unit stops the capacitance component connected to the output side of the rectification unit or the drive voltage conversion unit, or the electric energy stored in the power storage unit provided at the input side of the control voltage conversion unit. It is possible to continue power supply to the control means by using.

Therefore, the control means can maintain its operation for a certain period of time even after the AC power supply voltage drops. Then, during this period, by performing a termination process to bring each part of the apparatus to a predetermined termination state, it is possible to prevent the occurrence of problems that have occurred in the prior art, such as the motor remaining rotating and the correct data not being stored. You can

Further, when the power saving mode is executed, the input of the voltage drop detection signal to the control means is regulated. Therefore, even if the output voltage of the driving voltage conversion unit is changed to a voltage lower than the voltage during normal operation when the power saving mode is executed, it is possible to distinguish the voltage drop due to this and the AC voltage drop. Therefore, the output voltage of the driving voltage converter in the power saving mode can be set to an arbitrary value.

Further, since the operation is restarted when the elapsed time from the operation stop time of the drive voltage conversion section reaches the set time, the supply of the AC voltage is stopped for a short time like an instantaneous power failure. In this case, the image forming operation can be continued and the usability of the apparatus can be improved. In this case, by setting the set time to a time longer than the time required for the voltage supplied to the control means to fall to the operation guarantee voltage of the control means, it is possible to prevent a long-time power failure or a user power-off and an instantaneous power failure. Can be definitely distinguished.

If a predetermined voltage is not output from the start of the operation of the driving voltage converter until the waiting time elapses, an error signal is output to reliably notify the failure of the driving voltage converter. can do.

[Brief description of drawings]

FIG. 1 is a diagram showing an image forming apparatus according to the present invention.

FIG. 2 is a block diagram showing a configuration of a power supply unit of the first embodiment.

FIG. 3 is a block diagram showing an engine controller of the image forming apparatus.

FIG. 4 is a timing chart showing an operation when the AC voltage drops in the first embodiment.

FIG. 5 is a timing chart showing the operation of the power saving mode of the first embodiment.

FIG. 6 is a block diagram showing a configuration of a power supply unit of the second embodiment.

FIG. 7 is a timing chart showing the operation of the second embodiment when the AC voltage drops.

FIG. 8 is a block diagram showing a configuration of a power supply unit according to a third embodiment.

FIG. 9 is a block diagram of a power supply unit of a fourth embodiment.

FIG. 10 is a block diagram of an engine controller according to a fourth embodiment.

FIG. 11 is a flowchart showing an example of an operation procedure.

12 is a flowchart showing a subroutine of step # 22 of FIG.

FIG. 13 is a timing chart showing the transition of each voltage and each signal, showing a case where the AC input voltage does not recover from OFF.

FIG. 14 is a timing chart showing changes in each voltage and each signal, showing a case where the AC input voltage returns from OFF.

FIG. 15 is a flowchart showing a selection procedure.

FIG. 16 is a flowchart showing an operation procedure when the power is turned on.

FIG. 17 is a flowchart showing an operation procedure when a print command signal is input.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 engine controller (control means) 11 CPU 14, 71-77 serial EEPROM (storage medium) 51, 52, 53 drive motor (drive means) 100 rectifier 101 bridge rectifier circuit 102 smoothing capacitor 103 drive DC-DC converter (drive) Voltage converter) 104 backflow prevention diode 105 capacitor 106 controller DC-DC converter (control voltage converter) 108 regulator (auxiliary power supply) 111 drive AC-DC converter (drive voltage converter) 112 controller AC -DC converter (control voltage conversion unit) EG engine unit EC engine control signal PS power saving mode setting signal V3, V6, V9 output voltage (first power supply voltage) V2, V5, V8 output voltage (second power supply voltage) ) V7 output voltage (third power supply voltage)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 21/00 500 G03G 21/00 500 F term (reference) 2C061 AP03 AP04 AQ06 AR01 HH01 HK19 HN15 HT03 HT06 HT09 HV04 HV23 HV31 HV44 2H027 DA03 DA32 DA40 DE04 DE07 DE09 EB04 EC06 EC18 ED01 ED06 ED16 ED25 EE01 EE02 EE04 EE07 EE08 EE10 EF01 EF09 EF16 EJ17 EK01 EK03 EK05 EK06 EK13 GA30 GA54 GB07ZA

Claims (13)

[Claims] 1. An image forming apparatus comprising: driving means for driving each part of the apparatus; control means for controlling operations of the driving means and each part of the apparatus; and power supply means for supplying power to the driving means and the control means. In the device, the power supply means is connected to an output side of the rectifying unit for rectifying an AC voltage, smoothing it with a capacity component and converting it into a DC voltage, and converting the DC voltage into a voltage. A control voltage converter that outputs a power supply voltage of 1 and supplies it to the control means; and an output side of the rectifier, converts the DC voltage into a second power supply voltage, and outputs the second power supply voltage. And a drive voltage conversion unit that supplies the drive unit, wherein the control unit has at least one of the AC voltage, the output voltage of the rectification unit and the output voltage of the drive voltage conversion unit having a predetermined voltage value. Since A voltage monitoring unit that outputs a voltage drop detection signal when the voltage drops below; and a power supply control unit that stops the operation of the driving voltage conversion unit when the voltage drop detection signal is given from the voltage monitoring unit. An image forming apparatus comprising: 2. The power supply means is inserted between the rectifying section and the control voltage converting section to allow a current to flow from the rectifying section to the control voltage converting section. A backflow prevention unit that blocks a current in the reverse direction, and a power storage unit that is provided between the backflow prevention unit and the control voltage conversion unit and that stores electric energy supplied from the rectification unit are further included. Claim 1 characterized by the above.
The image forming apparatus according to item 1. 3. An image forming apparatus comprising: driving means for driving each part of the apparatus; control means for controlling operations of the driving means and each part of the apparatus; and power supply means for supplying power to the driving means and the control means. In the device, the power supply means is connected to an output side of the rectification unit for rectifying an AC voltage to convert it into a DC voltage, and converts the DC voltage into a voltage to output a first power supply voltage. And a control voltage converter for supplying to the controller, and a drive connected to the output side of the rectifier for converting the DC voltage to output a second power supply voltage and supplying it to the driver. And a control circuit that outputs a third power supply voltage having a voltage value substantially the same as the first power supply voltage by using the electrical energy stored in the capacitance component provided in the driving voltage conversion unit and the driving voltage conversion unit. Supply to the means A power supply unit, and the control unit detects a voltage drop when at least one of the AC voltage, the output voltage of the rectification unit, and the output voltage of the driving voltage conversion unit drops below a predetermined voltage value. A voltage monitoring unit that outputs a signal, and when the voltage drop detection signal is given from the voltage monitoring unit, while stopping the operation of the driving voltage conversion unit,
An image forming apparatus comprising: a power supply control unit that activates the auxiliary power supply unit. 4. An image forming apparatus comprising: driving means for driving each part of the apparatus; control means for controlling the operation of the driving means and each part of the apparatus; and power supply means for supplying power to the driving means and the control means. In the device, the power supply means converts a AC voltage into a first DC power supply voltage and supplies the voltage to the control means, and a control voltage converter converts the AC voltage into a second DC power supply voltage. A driving voltage conversion unit that supplies the driving unit, and a third power supply having a voltage value substantially the same as the first DC power supply voltage using the electric energy accumulated in the capacitive component provided in the driving voltage conversion unit. An auxiliary power supply unit that outputs a voltage and supplies the voltage to the control unit, wherein the control unit is configured such that at least one of the output voltage of the AC voltage and the drive voltage conversion unit has a predetermined voltage value or less. A voltage monitor that outputs a voltage drop detection signal when the voltage drops, and when the voltage drop detection signal is given from the voltage monitor, while stopping the operation of the drive voltage converter,
An image forming apparatus comprising: a power supply control unit that activates the auxiliary power supply unit. 5. The control means, when the voltage drop detection signal is given from the voltage monitoring unit, performs a termination process for bringing each unit of the device into a predetermined termination state. The image forming apparatus according to any one of 1 to 4. 6. The control means, as the end processing,
The image forming apparatus according to claim 5, wherein a stop operation of at least a motor included in the driving unit is performed. 7. The storage medium for storing predetermined data is further provided, and the control means performs at least a predetermined write operation to the storage medium as the end processing. The image forming apparatus described. 8. When the control unit is writing to the storage medium at the time when the voltage drop detection signal is given from the voltage monitoring unit, the control unit, as the predetermined write operation, The image forming apparatus according to claim 7, wherein an operation of completing writing of the data being written to the storage medium is performed. 9. The image forming apparatus according to claim 7, further comprising a cartridge detachable from the main body of the image forming apparatus, wherein the storage medium is disposed in the cartridge. apparatus. 10. A power saving mode capable of reducing power consumption by shifting each part of the apparatus to a standby state.
The image forming apparatus according to any one of claims 1 to 9, wherein the control unit is configured to, when the power saving mode is executed,
An image forming apparatus that regulates input of the voltage drop detection signal from the voltage monitoring unit to the power supply control unit. 11. The control means further comprises a timer that counts an elapsed time from the time when the power supply controller stops the operation of the driving voltage converter, and the power supply controller uses the timer. 11. The image forming apparatus according to claim 1, wherein when the counted elapsed time reaches a preset set time, the operation of the drive voltage converter is restarted. 12. The set time is such that, when the supply of the alternating voltage is stopped, the supply voltage to the control means is from the time when the operation of the drive voltage conversion section by the power supply control section is stopped. The image forming apparatus according to claim 11, wherein the image forming apparatus is set to a time longer than a time required until the operation guarantee voltage drops to a guaranteed value. 13. The control means further comprises an instruction control section for outputting an operation start instruction signal for instructing the operation start of the drive voltage conversion section, and an error signal control section for outputting a predetermined error signal. The power supply control unit starts the operation of the drive voltage conversion unit when the operation start instruction signal is given from the instruction control unit, and the voltage monitoring unit is configured to operate the drive voltage conversion unit. A voltage rise detection signal is output when the output voltage rises above the predetermined voltage value, and the error signal control unit sets a preset waiting time from the output time point of the operation start instruction signal by the instruction control unit. 13. The error signal is output when the voltage rise detection signal is not output from the voltage monitoring unit by the time of. Forming apparatus.