JP3474041B2 - Image forming device - Google Patents

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, and more particularly to a power supply unit for the image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine, a facsimile machine, a printer or the like generally has a display means for displaying an operating state, a key for inputting an operator's instruction, a device for image formation, and Electrical circuits that drive them,
A fixing unit for heating and fixing the toner image formed on the sheet, a temperature control circuit for energizing the fixing unit to control the temperature, a controller for reading the operator input and energizing / deactivating each element.
La, etc. The temperature control circuit is an energy-saving control mode (hereinafter referred to as a preheating mode) in which the fixing unit is energized to maintain the standby temperature until an image forming instruction is issued, and the temperature is raised to and maintained at the fixing temperature in response to the image forming instruction. The fixing temperature control mode controls the energization of the fixing means. Control
In the preheat mode, La turns off the display means excluding the display means representing this. 1 of this kind of image forming apparatus
One is disclosed in JP-A-59-201078. Further, the controller cuts off the power supply to peripheral devices and the like that do not need power supply in the standby state in the preheating mode to save power consumption (for example, Japanese Patent Laid-Open No. 5-33).
3636 publication).

FIG. 7 shows an image forming apparatus which is one of the objects of the present invention. When the original 2 is placed on the contact glass 1, the original size sensor 3 detects the presence or absence of the original 2 and the original size. When a copy start key (not shown) is pressed, a controller (not shown) turns on the exposure lamp 4 to expose the original 2. The reflected light of the original 2 is read by the CCD image sensor 9 via the first mirror 5, the second mirror 6, the third mirror 7 and the lens 8 and converted into an electric signal for image processing. The light emission of the laser diode 10 is modulated based on the image-processed data, and the laser light is applied to the photoconductor 15 through the cylinder lens 11, the polygon mirror 12, which rotates at a constant speed at a high speed, the lens 13, the writing mirror 14, and the like. It

Around the photosensitive member 15, a charging device 16, a developing device 17, a transfer belt 18, and a cleaning device 19 are provided. The photoconductor 15 has a cleaning device 19
After further cleaning, it is uniformly charged to a predetermined high potential by the charging device 16. When the charged photoconductor 15 is irradiated with the above laser beam, the surface potential on the photoconductor 15 changes according to the intensity of the irradiated light, and an electrostatic latent image is formed on the photoconductor 15. This electrostatic latent image becomes a toner image visualized by adsorbing toner by the developing device 17.

On the other hand, the transfer papers 21 stacked on the paper feed tray 20 are fed one by one, and the registration rollers 22 feed the transfer papers 21 so as to overlap the toner images on the photoconductor 15. Further, the transfer paper is the transfer belt 18 to which a high voltage is applied.
The toner image is transferred at the contact portion between the transfer belt 18 and the photoconductor 15.

The transfer paper on which the toner image has been transferred is further conveyed by the transfer belt 18 and sent to the fixing device 23 to fix the toner image. The transfer paper 21 that has been fixed is
The discharge sensor 24 detects that the transfer paper 21 is discharged outside the image forming apparatus.

As shown in FIG. 8, the image forming apparatus shown in FIG. 7 has an automatic document feeder 3 for automatically feeding the original 2 onto the contact glass 1 above the contact glass 30.
There is also a mode in which 2 is mounted. In this mode, when the originals 2 are set on the automatic original feeder 32, the original set sensor 33 detects that the originals 2 are set, and when the copy start key is pressed, the originals 2 are fed one by one. It is sent onto the contact glass 30 by the sending roller 34. The subsequent image forming operation is the same as that when the automatic document feeder 32 is not provided.

FIG. 9 shows an outline of one conventional DC power supply circuit used in the image forming apparatus as described above. The conventional DC power supply circuit shown in FIG. 9 includes a control system power supply circuit CPC for generating a voltage V _CC (mainly 5 V) for a controller, a sensor, etc., and a voltage V _AA (mainly for a drive system). Two
4V, 38V, other + 12V and -12V etc.)
Is a multi-output drive system power supply circuit DPC. Note that another AC power supply circuit is energized to the fixing device.

The drive system power supply circuit DPC has a large difference in output current between standby and image formation, and changes in output current during image formation are also large. Since the output current of the control system power supply circuit CPC is low compared to the drive system current and the change is not so large, the output voltage of the drive system is fed back when multiple outputs are obtained by one transformer as shown in FIG. Then, the energization level of the transformer primary winding is often controlled so that the output voltage of the drive system becomes a predetermined value. And
Other outputs are made constant by another regulator (for example, a three-terminal regulator) on the secondary side as needed.

In FIG. 9, the AC input through the noise filter NF11 is rectified by the rectifier circuit DB11 and smoothed by the smoothing capacitor C11 to be a DC input. The transformer T11 is wound with a primary winding N11 and a secondary winding N13 of a drive system source circuit DPC for _VAA output. Drive system The power supply circuit DPC is a forward DC / DC converter including a rectifying diode D12, a choke coil L11, a capacitor C12, and the like. Regular
The FET IC11 keeps the output voltage of the circuit DPC (feedback signal level of the FB11) constant so that the FET1
By controlling the duty of the pulse signal for ON / OFF of 1, the output voltage V _AA is made a constant voltage. FET
When 11 is turned on / off, a voltage is also induced in the secondary winding N13 of the control system power supply circuit CPC, but since it is not the voltage V _CC of a predetermined level, this is further regulated by another regulator RG 11 (In FIG. 9, it is a three-terminal regulator.)

In the image forming apparatus, the output W number of the DC power source greatly differs between the time of image formation and the time of standby. In the case of the DC power source having the configuration shown in FIG. 9, the power consumption of the DC power source circuit is high at the time of image formation. However, during standby, the electric power consumption of the electric circuit below the primary winding N12 of the drive system power supply circuit DPC is wasted, and the efficiency is reduced. In recent years, there has been a demand for power saving of electronic devices including image forming apparatuses.
In particular, in the case of an electrostatic image forming apparatus such as the image forming apparatus shown in FIGS. 7 and 8, the power consumption of the heater in the fixing device is large and its control has been devised. However, even when the fixing heater is turned on, the efficiency as a DC power source during standby is low, and power is consumed by a drive system power supply circuit that is unnecessary during standby.

In the conventional DC power supply shown in FIG. 9, for example, the ON / OFF operation of the FET 11 must be stopped in order to stop the drive system power supply circuit DPC which is not necessary during standby. However, when the ON / OFF operation of the FET 11 is stopped, the secondary winding N2 of the control system power circuit CPC is stopped.
Since no voltage is induced in 2 as well, the output of V _CC also stops.

[0013]

In order to save power of the image forming apparatus, in a standby state where no image is formed, power supply to the device used for image formation is cut off by a relay or the like. However, since the DC power supply of the power supply circuit is operating, D
Power loss occurs in the C power source. Further, in the image forming apparatus, the output capacity required for the DC power supply during image formation and the output capacity during standby differ greatly, and the DC power supply is designed with the output capacity during image formation. Power loss is large compared to the standby output capacity. That is, during standby, there is an excessive power loss as compared with the standby output capacity, and the power saving effect is low.

An object of the present invention is to further reduce power loss during standby.

[0015]

The image forming apparatus according to the present invention comprises a first transformer and a DC input to the primary winding of the transformer.
And a pulse signal for the FET
Turn the pulse signal on and off to keep the output voltage constant.
In response to a control signal that controls the duty and instructs off
A drive system power supply circuit that includes a regulator that turns off the FET, and that supplies a voltage to a device that operates during image formation;
Turn off the drive system power supply circuit during standby during non-image formation
A controller for applying the control signal to the regulator.
La; and second transformer and output voltage constant
A control system power supply circuit including a pressure regulator is provided for supplying electric power to the controller during the standby time and during image formation.

According to this, the control system power supply circuit supplies a voltage to the controller both during standby and during image formation, so that the controller turns on / off the drive system power supply circuit. You can During standby during non-image formation, the controller turns off the drive system power supply circuit.
Therefore , the standby power loss of the drive system power supply circuit during standby is eliminated, and the power saving effect is improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention is a document setting sensor 33 for detecting that a document is set.
A human body detection sensor 33 for detecting the presence of a person near the apparatus and a voltage detector 35 for detecting the rise of the output voltage of the drive system power supply circuit DPC are further provided, and the controller operates the input key (30). In response to the document set detection of the document set sensor 33 or the human body detection of the human body detection sensor 33, the drive system power supply circuit DPC is turned on, and the device used for image formation is turned on after the voltage detector 35 detects the voltage rising. / Turn off. According to this, when the operator (person) inputs an image forming instruction to the image forming apparatus or immediately before that, the controller turns on the drive system power supply circuit DPC. After waiting for the output voltage of the drive system power supply circuit DPC to rise, the drive of the device for image formation is started. Therefore, the image forming apparatus does not need to be provided with an operator switch for powering on the drive system for power saving, the operator does not need to operate the operator switch, and the operator's The drive system power supply is automatically turned on in response to an act for image formation, and the controller automatically starts image formation when the drive source power supply voltage rises to a predetermined drive voltage. When the image formation is completed, the drive system power supply circuit DPC is turned off.

In the preferred embodiment of the present invention, the drive system power supply circuit DPC and the control system power supply circuit CPC share the rectifiers DB21 and C21 for converting commercial AC into DC, but DC
Transformer T21 for DC / DC conversion (DC voltage conversion),
Each T22 is provided individually, and output voltage control by DC / DC conversion is performed by separate regulator ICs 21 and I.
The regulator IC22 of the control system power supply circuit CPC executes output voltage control while the rectifiers DB21 and C21 generate the output DC, and the regulator IC21 of the drive system power supply circuit DPC is In response to the ON / OFF instruction signal of the controller, the output voltage control is executed when the ON instruction signal is present, and the energization of the transformer primary winding N21 is interrupted while the OFF instruction signal is present. As a result, the transformer T2 of the drive system power supply circuit DPC is in standby.
There is no power consumption of 1, which greatly contributes to power saving.
While the controller consumes substantially no power during standby, the transformer T22 of the control system power supply circuit CPC is energized, so that the transformer T22 causes power loss.
Since the output capacity of the control system power supply circuit CPC is small, the power loss is small.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the main part of one embodiment of the present invention. The electric system shown in FIG. 1 is incorporated in the image forming apparatus shown in FIG. 7 (or FIG. 8), and the "DC system actuator &driver" in FIG. 1 is the image shown in FIG. It shows a driver, such as a motor, a clutch, and a solenoid, a high-voltage power source, a developing device of the forming apparatus, and various drivers (energizing circuits) for energizing them, that is, various devices used for image formation. The controller mainly includes the CPU 31 and gives control signals to various drivers via the I / O port 32. The DC power supply circuit supplies a required voltage to the controller and the various devices.

FIG. 2 shows the configuration of the DC power supply circuit shown in FIG. For the input section, the noise filter N is used as in the conventional case.
The AC input through F21 is rectified by the rectifier circuit DB21 and smoothed by the smoothing capacitor C21 to be a DC input. The drive system power circuit DPC and the control system power circuit CPC are
It has a magnetically independent transformer T21, T22, T2
A primary winding N21 and a secondary winding N22 are wound around 1, and a primary winding N23 and a secondary winding N24 are wound around T22. The drive system power circuit DPC includes a rectifying diode D21, a commutation diode D22, a choke coil L21, and a capacitor C2.
It is a forward type DC / DC converter configured by 2. The control system power supply circuit CPC is a flyback DC / DC converter including a rectifying diode D23 and a capacitor C23. However, although not shown, the control system power supply circuit CPC may also be of the forward type.

Drive system power supply circuit DPC and control system power supply circuit C
PC is an independent regulator (control circuit) IC21 and I
The regulator IC21 has a C22, and the regulator IC21 keeps the output voltage V _AA (the level of the signal fed back by the FB21) of the drive system power supply circuit DPC constant.
The duty of the pulse signal for ON / OFF of 1 is controlled. The regulator IC 22 is a control system power supply circuit CP.
In order to keep the output voltage V _{CC of} C (the level of the signal fed back by the FB 22) constant,
The duty of the pulse signal for N / OFF is controlled.

The DC power supply circuit is constructed as described above and I
C21 operation / stop, ON / OF from controller
By controlling the F signal, when no required voltage V _AA to be applied to the drive system (i.e., standby), the regulator - the operation of the motor IC21 is stopped, even if the standby (output power low) The efficiency as a DC power supply circuit can be improved. Further, control of the heater of the fixing device (control of preheating mode /
In synchronization with the switching of the control) at the time of image formation, or vice versa, in synchronism with the OFF / ON of the drive system power supply circuit DPC heater control (pre-heating mode - switching the de control during the control / image formation) Turns on the main switch of the image forming apparatus.
It is possible to limit the power consumption of the image forming apparatus during standby without limit without using FF.

FIG. 3 shows an outline of the control operation of the CPU 31 shown in FIG. The main switch (not shown) is closed,
As a result, when the control system power supply circuit CPC generates the voltage V _CC , this is added to the controller and C of the controller is generated.
The PU 31 sets internal registers, counters, timers, etc. to standby values, and sets standby signal levels for input and output ports for devices used for image formation (step 101). In the following, in parentheses, the word "step" is omitted and only the step number is shown.

When the initialization (101) is completed, the CPU 31
Reads the status of the sensor etc. and checks whether there is any abnormality (a state where image formation cannot be started) (102, 10
3) If there is an abnormality, it is displayed on the operation / display board 30 (104). If there is no abnormality, the "preheat mode" is instructed to the AC power supply circuit (not shown) for supplying power to the fixing device, and the operation / display board 30 is waited for input. (105). The AC power supply circuit starts energization control for temperature control in which the heater temperature is set to a target temperature (low temperature value) addressed during standby (preheating). In the "input reading" (105), input such as copy number input, copy magnification input, and recording density input is written in the register. Further, the detection signal of the human body detection sensor 33 for detecting the approach of the human body near the operation / display board 30 is read, and the document is set on the contact glass plate (in the case of FIG. 7) or the automatic document feeder. Then, the detection signal of the document set sensor 34 for detecting the document set (in FIG. 8) is read and written in the register. The register is a memory area allocated to the internal memory of the CPU 31.

Then, the detection signal of the human body detection sensor 33 is switched from off (without a person) to on (with a person), the document set sensor 34 is switched from off (without a document) to on (with a document), Alternatively, the operation / display board 30
Input key for setting copy conditions or for instructing copy start
If any of the above operations has been established (106 to 108, 114, 115), and if any of the operations is established, an ON (V _AA output instruction) signal is given to the regulator IC 21 to fix it. The "image forming mode" is instructed to the AC power supply circuit that supplies power to the apparatus (109). The AC power supply circuit keeps the target temperature for heater temperature control in standby (preheat).
The high temperature value suitable for the image fixing is switched from the low temperature value addressed to (3) to continue the heater temperature control.

Next, the CPU 31 waits for the output signal of the voltage detector 35 to change to a level at which a predetermined voltage or higher is detected (110). When the output signal of the voltage detector 35 is converted to a level indicating that the output voltage V _AA of the drive system power supply circuit DPC is equal to or higher than a predetermined voltage, the CPU 31 causes the electric motor (polygon motor) that rotationally drives the polygon mirror 12. −
To the motor driver for energizing the motor (111), and to the register PMF, the drive system power supply circuit D
"1" indicating that the PC is on (voltage output) is written, and clocking is started (113). When the laser beam is reflected by the polygon mirror 12 to expose the photoconductor (FIG. 7,
In FIG. 8), it is preferable to stop the rotation of the polygon motor for rotating the polygon mirror 12 for quietness, power saving and reduction of mechanical wear except when the image is formed. It takes several seconds to several tens of seconds to stabilize the mirror 12 from the stopped state to a predetermined rotation speed. A time Ts, which is slightly longer than this delay time, is set as a waiting time from the start of rotation driving of the polygon mirror 12 to the start of exposure. In step 113, the polygon mirror
The measurement of the elapsed time Tu from the start of the rotation drive of 12 is started.

When the input is a start key operation of the operation / display board 30, the CPU 31 causes the elapsed time Tu.
However, check if it has exceeded the set value Ts (11
4, 116, 117) and the elapsed time Tu is equal to or more than the set value Ts, the scanner motor for driving the original scanning system such as the exposure lamps 4, mirrors 5 to 7 is driven to perform one copy cycle ( (1 image forming process) is executed (118), the copy number counter is incremented by 1 and it is checked whether the copy number has reached the set number (119). Copy - to trees and the number has not reached the set number of sheets, and 1 copy -
The cycle (118) is executed. When the set number of sheets is reached, cleaning of the photoconductor and transfer belt (duration of)
Etc., set the post-processing (end cycle) (120),
The process returns to “input reading” 105. When there is no start input from the operation / display board 30 and the end cycle ends, it is checked whether the paper discharge sensor is detecting the copy paper (during paper discharge) (121, 122). Does not detect the copy paper, the end cycle is stopped (123). Then, an OFF signal is given to the regulator IC 21, the register PMF is cleared, and the "preheat mode" is instructed to the AC power supply circuit for supplying power to the fixing device (124). Then, the process returns to "input reading" (105).

Steps 106-108, 114, 115
If the operator's access to the copying machine (approach, document setting or key input) is detected, and the drive system power supply circuit DPC is not turned on at that time (if the data in the register PMF is 0, Drive system power supply circuit DP
Since C is turned on, there is little waste of power. The output voltage V _AA after turning on the drive system power supply circuit DPC is takes a little time to rise to a predetermined voltage. For example, when the controller attempts to start the image forming operation immediately after the start key is pressed while the drive system power supply circuit DPC is off, V _AA is low, resulting in insufficient torque of the motor or the like. Insufficient input voltage to the high voltage power supply,
As an image forming apparatus, a paper jam may occur and an abnormal image may occur. To eliminate these problems, step 11
0, the voltage detector 35, waits to detect the V _AA is equal to or greater than a set value, after becoming higher than the set value, Porigonmo rotates the polygon mirror -12 - driving the motor (111) . Then, "1" (meaning power supply output OK) is written in the register PMF (112). Since it takes several seconds to several tens of seconds to raise and stabilize the rotation speed of the polygon motor from the stopped state to the set value, the image forming process is started after this delay time ( 114, 116, 117). FIG. 4 shows the above operation timing.

When an ON signal is given to the regulator IC 21 in the AC power supply circuit for supplying power to the fixing device (1
09) is instructed to "image forming mode". Therefore, in the fixing device, when the regulator IC 21 is turned on, the temperature rise from the preheating temperature to the fixing temperature starts. When the scanner motor is driven in "1 copy cycle" (118) in response to the start input, the drive system power supply circuit DPC is turned on and turned on.
Since s or more has elapsed, the output voltage V _AA of the drive system power supply circuit DPC is stable at or above the set value, so the scan of the document scanning system is stable.

As shown in FIG. 5, the paper discharge sensor 24 provided at the rear of the fixing device 23 is a transfer paper 21 (copy paper).
Is detected, a low level L output is produced, and a high level H output is produced when the transfer paper 21 is not present. When the transfer paper 21 that has passed through the fixing device 23 reaches the upper side of the paper ejection sensor, the paper ejection sensor 24 outputs a low level L, the transfer paper 21 is conveyed, and the rear end of the transfer paper 21 passes the paper ejection sensor. After that, a high level H output is produced. Thus, when the output of the paper discharge sensor 24 changes from H → L → H, the CPU 3
1 determines that the transfer paper 21 is ejected. "End cycle stop" through "End cycle setting" (120)
After (123), if the output of the paper discharge sensor 24 has already passed the change of H → L → H of the last transfer paper, or if this change ends, the CPU 31 regulates.
A "preheat mode" is instructed to the AC power supply circuit for supplying an OFF signal to the IC 21 to supply power to the fixing device (124).

As described above, since the operation of the drive system power supply circuit DPC is stopped immediately after the image formation is completed, the drive system power supply circuit DPC operates only for the minimum necessary period, and the power is wasted except when the image is formed. .

According to the embodiment described above, the drive system power supply circuit DPC for generating the drive voltage required only during image formation.
And control system power supply circuit C that generates the minimum required voltage during standby
Since the transformer and the control are independent of the PC, the loss of the DC power supply is suppressed, and the drive system power supply circuit DP is required only during image formation during standby.
Since the operation of C is stopped, the efficiency of the DC power supply is improved.

FIG. 6 shows a modification of the DC power supply circuit shown in FIG. In this modification, a three-terminal regulator IC31 is used as the control system power supply circuit CPC, like the control system power supply circuit CPC of the conventional example shown in FIG. The drive system power supply circuit DPC shown in FIG. 6 is the same as that shown in FIG.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an electric system according to an embodiment of the present invention, which is combined with the image forming mechanism shown in FIG. 7 or 8.

FIG. 2 is a block diagram showing a configuration of a DC power supply circuit shown in FIG.

FIG. 3 is a flowchart showing an outline of a control operation of the CPU 31 shown in FIG.

4 shows the output voltage V _AA of the drive system power supply circuit DPC shown in FIG. 2 and the polygon shown in FIG. 7 from “input reading” (105) to “1 copy cycle” (118) in FIG. It is a time chart which shows the change of the rotation speed of the mirror 12.

5 is a time chart showing changes in the detection signal of the paper discharge sensor and the output voltage V _AA of the drive system power supply circuit DPC shown in FIG. 2 when the final copy paper is discharged.

6 is a block diagram showing a modification of the drive system power supply circuit DPC shown in FIG.

7 is a vertical sectional view showing an image forming mechanism to which the electric system shown in FIG. 1 is connected.

FIG. 8 is a vertical cross-sectional view showing an image forming mechanism to which the electric system shown in FIG. 1 is connected.

FIG. 9 is a block diagram showing a configuration of a conventional DC power supply circuit of an image forming apparatus.

[Explanation of symbols]

1: Contact Glass 2: Original 3: Original Size Sensor 4: Exposure Lamp 5: First Mirror 6: Second Mirror 7: Third Mirror 8: Lens 9: CCD Image Sensor 10: Laser Diode 11: cylinder lens 12: polygon mirror 13: lens 14: mirror 15: photoconductor 16: charging device 17: developing device 18: transfer belt 19: cleaning device 20: paper feed tray 21: transfer paper 22: registrar -La 23: Fixing device 24: Paper discharge sensor 32: Automatic document feeding device 33: Document setting sensor 34: Feeding roller NF11: Noise filter DB11: Rectifier circuit C11: Smoothing capacitors T11, T21, T22: Transformer N11 , N21, N23: primary windings N12, N13, N22, N24: secondary winding D12: diode L11: choke coil C12 : Capacitor IC11, RG11, IC21, IC22: Regulator-
FB11, FB21, FB22: Voltage feedback circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 21/00 370-512 G03G 15/20 109 H02M 3/28

Claims (6)

(57) [Claims] 1. A first transformer and a primary winding of the transformer.
FET that feeds DC input to the
The pulse signal is turned on / off to keep the output voltage constant.
Control signal that controls the duty of the loose signal and instructs it to turn off.
A regulator that turns off the FET in response to the signal
Seen, the drive system power supply circuit for supplying a voltage to the device that operates at the time of image formation; turning off the drive system power supply circuit during standby of the non-image-forming
A controller for applying the control signal to the regulator.
La; and a second transformer, and a leg that regulates the output voltage
Comprises Regulator, the at the standby and the image forming control - control system power supply circuit for supplying electric power to the La; image forming apparatus comprising: a. Wherein said controller - la, the input key - control signal for instructing the on of the drive system power supply circuit in response to the operation of the
To the regulator of the drive system power supply circuit,
Then the regulator turns on / off the FET with a pulse signal.
Turn off the pulse signal to keep the output voltage constant.
The image forming apparatus according to claim 1 , which controls the temperature . 3. The apparatus further comprises original detection means for detecting the setting of an original, and the controller responds to the detection by the original detection means to turn on the drive system power supply circuit .
The control signal for instructing the regulation of the drive system power supply circuit.
And the regulator causes the FET to
Turn on / off with pulse signal to keep output voltage constant
The image forming apparatus according to claim 1 , wherein the duty of the pulse signal is controlled . 4. The apparatus further comprises a human body detection means for detecting the presence of a person of the device near the controller - La, finger on the drive system power supply circuit in response to the detection of said human body detection means
The control signal shown to the regulator of the drive system power supply circuit
Which causes the regulator to pulse the FET.
Pulse signal to turn it on and off to keep the output voltage constant.
The image forming apparatus according to claim 1, wherein the duty of the scan signal is controlled . 5. The apparatus further comprises voltage detection means for detecting the rise of the output voltage of the drive system power supply circuit, and the controller is provided for image formation after the rise is detected by the voltage detection means. 2. The device is turned on / off.
The image forming apparatus according to claim 2, claim 3, or claim 4. 6. A controller supplies a control signal for turning off the drive system power supply circuit after the image forming operation is completed.
It gives the chromatography data, according to claim 1, claim 2, claim 3, claim 4 or claim 5 image forming apparatus according.