JP3718376B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine or a printer.
[0002]
[Prior art]
When an error occurs in the image forming operation in the image forming apparatus, for example, when a so-called paper jam occurs in which the recording paper to be transported is jammed in the transport path, or the operator opens the door of the apparatus housing or presses the emergency stop button for the image forming operation. When the button is pressed, it is necessary to urgently stop the image forming operation. Japanese Patent Application Laid-Open No. 10-114124 discloses a power supply voltage supplied to a main motor that rotationally drives a photoconductor as an image carrier when an error occurs, and a laser scanner unit (LSU) as an exposure unit that exposes the surface of the photoconductor. ) Supply the power supply voltage supplied to the polygon motor that drives the polygon mirror and the voltage application device to the charger that charges the surface of the photoreceptor and the developer that develops the electrostatic latent image formed on the surface of the photoreceptor. An image forming apparatus that simultaneously shuts off all the power supply voltages is disclosed.
[0003]
FIG. 8 is a timing chart showing an emergency stop sequence when an error occurs in the image forming operation of the conventional image forming apparatus. As soon as an error occurs and the power supply voltages are cut off all at once, the main motor control signal s1, the voltage application device process voltage control signal s2, and the polygon motor control signal s3 are turned off.
[0004]
Here, a period from the time when the main motor control signal s1 is turned off to the time point p1 when the driving voltage v1 of the main motor becomes 0 (zero) and rotation of the photosensitive member stops is defined as t1. A period from the time when the process voltage control signal s2 of the voltage application device is turned off to the time p2a when the main charger v2a of the charger becomes 0 (zero) is defined as t2a. A period from the time when the process voltage control signal s2 of the voltage applying device is turned off to the time p2b when the developing bias v2b of the developing device becomes 0 (zero) is defined as t2b. A period from the time when the polygon motor control signal s3 is turned off to the time point p3 when the driving voltage v3 of the polygon motor becomes 0 (zero) and the driving of the polygon mirror stops is defined as t3.
[0005]
When the main motor control signal s1 is turned off and the period t1 elapses, the main motor drive voltage v1 becomes zero. Further, when the period t3 elapses after the polygon motor control signal s3 is turned off, the polygon motor drive voltage v3 becomes zero. At this time, the main motor is not stopped instantaneously by the inertial force of the photoconductor and the polygon motor is not instantaneously stopped by the inertial force of the polygon mirror, and the control signals s1 and s3 are turned off and the drive voltages v1 and v2 are 0. After that, it is driven for a predetermined period.
[0006]
Further, when the process voltage control signal s2 is turned off and the period t2a elapses, the main charger v2a becomes zero. Further, when the process voltage control signal s2 is turned off and the period t2b elapses, the development bias v2b becomes zero. At this time, since the voltage values applied to the charger and the developing device are different from each other, the developing device having a lower applied voltage value becomes 0 earlier than the charging device. Therefore, a difference occurs between the periods t2a and t2b. Further, the periods t2a and t2b are set shorter than the periods t1 and t3.
[0007]
[Problems to be solved by the invention]
The above-described differences occur in the timing of stopping the main motor, polygon motor, charger, and developer. For example, when the photoconductor rotates with the voltage value of the charger being 0, exposure is performed on the surface of the photoconductor that is not charged, and the potential of the exposed photoconductor surface is lowered. When the photosensitive member rotates in the next process, the toner from the developing device adheres to the portion where the potential is lowered and is collected as unnecessary toner, so that the toner consumption increases.
[0008]
In addition, when the developing bias becomes 0 while the photoconductor is rotating with inertial force, the photoconductor charged with no developing bias applied passes through the developing unit, and carriers are formed on the surface of the photoconductor. Adhere to. Since the carrier is specifically iron powder, the surface of the photoreceptor is abraded by the attached carrier, and the surface of the photoreceptor is scratched, thereby shortening the life of the photoreceptor and reducing the image quality.
[0009]
As described above, in the conventional image forming apparatus, when the image forming operation is urgently stopped due to the occurrence of an error in the image forming operation, an unexpected secondary trouble occurs in the normal image forming operation. As a result, problems such as a significant decrease in the life of the photoconductor and a deterioration in image quality due to variations in toner density occur, and an image cannot be stably formed.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of stably forming an image by stopping the image forming operation according to a predetermined sequence when an error occurs in the image forming operation and preventing a secondary trouble accompanying the occurrence of the error. Is to provide.
[0011]
[Means for Solving the Problems]
The present invention comprises an image carrier,
An image carrier driving motor for rotationally driving the image carrier;
Charging means for charging the surface of the image carrier to a predetermined potential by the voltage from the voltage applying means;
Exposure means for exposing the surface of the image carrier to form an electrostatic latent image corresponding to the image signal;
An exposure drive motor for driving the exposure means;
Developing means for developing the electrostatic latent image by a voltage from the voltage applying means to form a visible image;
A paper feed roller for feeding a recording paper for transferring a visible image to a transfer area;
Control means for controlling the image carrier driving motor, the exposure driving motor and the voltage applying means by each control signal;
In an image forming apparatus including an image carrier driving motor, an exposure driving motor, a voltage applying unit, and a power source for supplying a power source voltage to the control unit,
The control unit includes a step-up transformer, a diode, a capacitor, and a resistor, and among these, the capacitor is configured such that the operation timing of the image carrier driving motor, the exposure driving motor, the charging unit, and the developing unit can be adjusted,
When an error relating to image formation occurs , it is determined that the supply of power should not be stopped, and when the image carrier driving motor is driven, a first process executed independently of other process stop sequences A first process stop sequence including a process stop sequence including operation control of the motor is executed, and in the first process stop sequence, control signals for the image carrier drive motor and the exposure drive motor are turned off. After that, the control signal of the voltage applying means is turned off,
This is a third process stop sequence that is executed independently of other process stop sequences when an error relating to image formation that may cause the operator to touch the inside of the apparatus occurs. If it is determined that the image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so that the power supply voltage is turned off immediately and the third process stop sequence is executed, the image carrier drive motor The period from when the control signal is turned off until the rotation of the image carrier stops is T1, and the period from when the control signal of the exposure drive motor is turned off until the exposure by the exposure means is stopped is T3. When the period from when the control signal of the applying unit is turned off to when the applied voltage to the charging unit and the developing unit becomes 0 (zero) is T2. Is set to T1> T3 and T1 <T2,
When an error relating to image formation occurs and it is determined that the supply of power should not be stopped and the image carrier driving motor is stopped, the second process is executed independently of other process stop sequences. The image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so as to execute a second process stop sequence that does not include the operation control of the motor . In the process stop sequence of No. 2, the image forming apparatus is characterized in that the control signal of the voltage applying unit is turned off after the control signal of the exposure drive motor is turned off .
[0012]
According to the present invention, the operation timing of the image carrier driving motor, the exposure driving motor, the charging unit and the developing unit can be adjusted by the capacitor. When an error occurs in the image forming operation, different process stop sequences are executed depending on whether the drive motor of the image carrier is driven or stopped. That is, in the image forming apparatus of the present invention, a process stop sequence corresponding to the situation when an error occurs is executed. The first process stop sequence when the drive motor of the image carrier is driving includes operation control of the driving motor. Further, the control means controls the image carrier driving motor, the exposure driving motor, and the voltage applying means according to each control signal so that the power supply voltage is immediately turned off and the third process stop sequence is executed when an error relating to image formation occurs. Control. The second process stop sequence when the drive motor of the image carrier is stopped does not include operation control of the stopped motor. The first, second, and third process stop sequences are executed independently of other process stop sequences.
When an error relating to image formation occurs, it is determined that the supply of power should not be stopped, and when the image carrier driving motor is driven, a first process executed independently of other process stop sequences A first process stop sequence including a process stop sequence including operation control of the motor is executed, and in the first process stop sequence, control signals for the image carrier drive motor and the exposure drive motor are turned off. Thereafter, the control signal of the voltage applying means is turned off.
This is a third process stop sequence that is executed independently of other process stop sequences when an error relating to image formation that may cause the operator to touch the inside of the apparatus occurs. If it is determined that the image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so that the power supply voltage is turned off immediately and the third process stop sequence is executed, the image carrier drive motor The period from when the control signal is turned off until the rotation of the image carrier stops is T1, and the period from when the control signal of the exposure drive motor is turned off until the exposure by the exposure means is stopped is T3. When the period from when the control signal of the applying unit is turned off to when the applied voltage to the charging unit and the developing unit becomes 0 (zero) is T2. It is set to T1> T3 and T1 <T2.
When an error relating to image formation occurs and it is determined that the supply of power should not be stopped and the image carrier driving motor is stopped, the second process is executed independently of other process stop sequences. The image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so as to execute a second process stop sequence that does not include the operation control of the motor. In the process stop sequence 2, after the exposure drive motor control signal is turned off, the voltage application means control signal is turned off.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an image forming apparatus 21 according to an embodiment of the present invention. The image forming apparatus 21 has a document table 1 made of transparent glass or the like on the upper surface. A scanner optical system 2 is disposed below the document table 1. The scanner optical system 2 includes an exposure light source 3 for irradiating light on a document placed on the document table 1, a plurality of reflecting mirrors 6 for guiding reflected light from the document to a CCD (photoelectric conversion element) 5, and a CCD 5 for reflected light. The imaging lens 4 and the CCD 5 are arranged in the optical path to the. Image data of the original read by the CCD 5 is subjected to image processing. The LSU 7 irradiates the surface of the photoconductor 8 with a laser beam corresponding to the image data subjected to image processing, whereby an electrostatic latent image is formed on the surface of the photoconductor 8.
[0029]
The photoconductor 8 has a drum shape and is configured to be rotatable in a predetermined rotation direction A. Around the photoconductor 8, a developing device 9, a transfer charger 10, a cleaning device 11, a charger 12, and an LSU 7 are arranged in this order from the irradiation position of the laser light toward the rotation direction of the photoconductor 8. An image forming unit is configured including the photoconductor 8, the developing device 9, the transfer charger 10, the cleaning device 11, the charger 12, and the LSU 7.
[0030]
The developing device 9 develops the electrostatic latent image on the surface of the photoconductor 8 exposed by the laser light into a visible image with toner. The transfer charger 10 transfers the toner image on the photoconductor 8 to the recording paper P. The cleaning device 11 removes toner remaining on the surface of the photoconductor 8. The charger 12 charges the surface of the photoconductor 8 to a predetermined potential. The LSU 7 irradiates the surface of the photoreceptor 8 with laser light as described above.
[0031]
The recording paper P to which the toner image is transferred is stored in a paper cassette 13 disposed at the lower part of the image forming apparatus 21. The recording paper P stored in the paper cassette 13 is fed one by one to the transfer area of the image forming unit by a half-moon shaped paper feeding roller 14. Further, a pre-registration detection switch 15 for detecting the passage of the recording paper P is disposed on the downstream side in the conveyance direction of the recording paper P, and further on the downstream side based on an output signal from the switch 15. A registration roller 16 for aligning the toner image on 8 and the recording paper P is disposed. The toner image on the photoconductor 8 is transferred to the recording paper P fed to the transfer area by the transfer charger 10.
[0032]
The recording paper P on which the toner image is transferred in the transfer area of the image forming unit is conveyed to a fixing roller 17 disposed on a path for discharging the recording paper P, and the toner image is fixed by heat. Further, a fixing paper detection switch 18 for detecting that the recording paper P has passed through the fixing roller 17 is disposed on the downstream side in the conveyance direction of the recording paper P, and recording is performed on the further downstream side before the paper discharge roller 20. A paper discharge detection switch 19 that detects the passage of the paper P is disposed, and the paper discharge roller 20 is disposed further downstream. The recording paper P discharged by the paper discharge roller 20 is discharged, for example, beside the image forming unit, above the paper cassette 13 and below the scanner optical system 2.
[0033]
FIG. 2 is a block diagram of the image forming apparatus 21. A power supply voltage is supplied from the power source 59 to the image forming apparatus 21, and the image forming operation of the image forming apparatus 21 is controlled by the control unit 50. Specifically, the control unit 50 controls operations of the main motor drive control unit 51, the polygon motor drive control unit 52, and the process voltage control unit 53. The main motor drive control unit 51 controls the operation of the main motor 55 that rotationally drives the photosensitive member 8. The polygon motor drive control unit 52 controls the operation of the polygon motor 56 that drives the polygon mirror of the LSU 7. The process voltage controller 53 controls the voltage application operation of the high voltage generator 54 that applies a voltage to the charger 12 and the developing device 9.
[0034]
Operation control of the main motor drive control unit 51, the polygon motor drive control unit 52, and the process voltage control unit 53 by the control unit 50 is performed by a predetermined control signal. That is, the main motor drive control unit 51 outputs a main motor control signal, the polygon motor drive control 52 outputs a polygon motor control signal, and the process voltage control unit 53 outputs a process voltage control signal.
[0035]
As shown in FIG. 3, the main motor drive controller 51, polygon motor drive controller 52, and process voltage controller 53 include a step-up transformer 57, diodes D1, D2, capacitors C1, C2, resistors R1, R2, and the like. And is grounded via a load 58. As described above, the operation timings of the main motor 55, the polygon motor 56, the charger 2 and the developing device 9 are adjusted by the capacitors C1 and C2 constituting the control units 51 to 53. That is, by supplying the charged voltages to the capacitors C1 and C2, the operation timing is delayed, the motor is rotated, and the voltage is applied to the charger 12 and the developing device 9.
[0036]
FIG. 4 is a flowchart showing a stop operation when an error occurs in the image forming operation of the image forming apparatus 1. When the image forming process is started, in step S1, the control unit 50 determines whether an error in the image forming operation has occurred. When it is determined that no error has occurred, the process proceeds to step S2, where a normal image forming process is executed and the operation is terminated. On the other hand, when it is determined that an error has occurred, the process proceeds to step S3.
[0037]
In step S3, the error content is analyzed. In the next step S4, it is determined whether or not the supply of power from the power source 59 is stopped. When stopped, the process proceeds to step S8, a third process stop sequence described later is executed, and the operation is ended. On the other hand, when the supply of power is not stopped, the process proceeds to step S5.
[0038]
In step S5, it is determined whether or not the main motor 55 is being driven. When the driving is in progress, the process proceeds to step S6, a first process stop sequence described later is executed, and the operation is terminated. On the other hand, when the main motor 55 is stopped, the process proceeds to step S7, a second process stop sequence described later is executed, and the operation is ended.
[0039]
FIG. 5 is a timing chart showing the first process stop sequence. Here, a period from the time when the control signal S1 of the main motor 55 is turned off to the time P1 when the driving voltage V1 of the main motor 55 becomes 0 (zero) and the rotation of the photoconductor 8 stops is defined as T1. A period from the time when the control signal S3 of the polygon motor 56 is turned off to the time P3 when the driving voltage V3 of the polygon motor 56 becomes 0 (zero) and the exposure by the polygon mirror of the LSU 7 stops is defined as T3. Further, from the time when the process voltage control signal S2 of the process voltage control unit 53 corresponding to the voltage applying means is turned off, the time P2 when the main charger V2a that is the voltage applied to the charger 12 becomes 0 (zero) and the developing device A period up to time point P2 when the developing bias V2b, which is an applied voltage to 9, becomes 0 (zero) is defined as T2.
[0040]
In the first process stop sequence executed when the voltage supply is not stopped and the main motor 55 is being driven, an error occurs and at the same time, the main motor control signal S1 and the polygon motor control signal S3 is turned off. Subsequently, the period T3 elapses, the polygon motor drive voltage V3 becomes 0, and the polygon motor 56 stops. Further, after the period T1 has elapsed, the main motor drive voltage V1 becomes 0 and the main motor 55 stops. When the main motor 55 is completely stopped after the polygon motor 56 is completely stopped, the process voltage control signal S2 is turned off. Subsequently, when the period T2 elapses, the main charger V2a to the charger 12 and the developing bias V2b to the developing device 9 become zero.
[0041]
FIG. 6 is a timing chart showing the second process stop sequence. In the second process stop sequence executed when the supply of voltage is not stopped and the main motor 55 is stopped, the polygon motor control signal S3 is turned off simultaneously with the occurrence of an error. Subsequently, the period T3 elapses, the polygon motor drive voltage V3 becomes 0, and the polygon motor 56 stops. When the polygon motor 56 is completely stopped, the process voltage control signal S2 is turned off. Subsequently, when the period T2 elapses, the main charger V2a to the charger 12 and the developing bias V2b to the developing device 9 become zero.
[0042]
FIG. 7 is a timing chart showing the third process stop sequence. In the third process stop sequence executed when the supply of power is stopped, the main motor control signal S1, the polygon motor control signal S3, and the process voltage control signal S2 are turned off simultaneously with stopping the power supply. Subsequently, the period T3 elapses, the polygon motor drive voltage V3 becomes 0, and the polygon motor 56 stops. Further, after the period T1 has elapsed, the main motor drive voltage V1 becomes 0 and the main motor 55 stops. Further, after the period T2 has elapsed, the main charger V2a to the charger 12 and the developing bias V2b to the developing device 9 become zero.
[0043]
In order to stop the image forming operation at the timing as described above, the period T1 is set to be longer than the period T3, and the period T2 is set to be longer than the period T1. That is, such timing can be adjusted by the delay capacitors C1 and C2 inserted in the main motor drive control unit 51, the polygon motor drive control unit 52, and the process voltage control unit 53.
[0044]
As described above, according to the image forming apparatus 21 of the present embodiment, when an error relating to image formation occurs, when the main motor 55 that rotationally drives the photosensitive member 8 is driven, the first control including the operation control of the motor 55 is performed. When the process stop sequence is executed and the main motor 55 is stopped, the second process stop sequence not including the operation control of the motor 55 is executed. That is, a process stop sequence corresponding to the state of the main motor 55 when an error occurs is executed.
[0045]
According to the first and second process stop sequences as described above, the surface of the photoconductor 8 that is not charged is not exposed, and the toner adheres to the surface of the photoconductor 8 whose potential has been lowered. As a result, an increase in toner consumption can be prevented. In addition, the photosensitive member 8 charged without applying a developing bias does not pass through the developing unit 9, and so-called carrier rising in which carriers adhere to the surface of the photosensitive member 8 can be prevented. Since the carrier can be prevented from rising, it is possible to prevent the surface of the photoconductor 8 from being worn by the attached carrier and the surface of the photoconductor 8 from being damaged. Therefore, it is possible to reliably prevent secondary troubles accompanying the occurrence of errors in the image forming operation and to form images stably.
[0046]
Further, when an error relating to image formation occurs, particularly when an error that may cause the operator to touch the inside of the apparatus occurs, the power supply voltage is immediately turned off and the third process stop sequence is executed. Even with the third process stop sequence as described above, as with the first and second process stop sequences, secondary troubles due to the occurrence of errors in the image forming operation can be reliably prevented, and images can be stably displayed. Can be formed.
[0047]
In the image forming apparatus 21, the period from when the error occurs until the main motor control signal S1 is turned off is T4, and the period required for one rotation of the paper feed roller 14 is T5, and T4> T5 may be set. It belongs to the scope of the present invention. This also reliably prevents secondary troubles associated with the occurrence of errors in the image forming operation, and enables stable image formation.
[0048]
【The invention's effect】
As described above, according to the present invention, the operation timing of the image carrier driving motor, the exposure driving motor, the charging unit, and the developing unit can be adjusted by the capacitor. When an error relating to image formation occurs in the image forming apparatus, when the image carrier driving motor is driven, a first process stop sequence including operation control of the motor is executed. When this occurs, the image carrier driving motor, the exposure driving motor, and the voltage applying means are controlled by the respective control signals so that the power supply voltage is immediately turned off and the third process stop sequence is executed. When an error relating to image formation occurs in the image forming apparatus, a second process stop sequence not including operation control of the motor is executed when the image carrier driving motor is stopped. The first, second, and third process stop sequences are executed independently of other process stop sequences.
When an error relating to image formation occurs, it is determined that the supply of power should not be stopped, and when the image carrier driving motor is driven, a first process executed independently of other process stop sequences A first process stop sequence including a process stop sequence including operation control of the motor is executed, and in the first process stop sequence, control signals for the image carrier drive motor and the exposure drive motor are turned off. Thereafter, the control signal of the voltage applying means is turned off.
This is a third process stop sequence that is executed independently of other process stop sequences when an error relating to image formation that may cause the operator to touch the inside of the apparatus occurs. If it is determined that the image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so that the power supply voltage is turned off immediately and the third process stop sequence is executed, the image carrier drive motor The period from when the control signal is turned off until the rotation of the image carrier stops is T1, and the period from when the control signal of the exposure drive motor is turned off until the exposure by the exposure means is stopped is T3. When the period from when the control signal of the applying unit is turned off to when the applied voltage to the charging unit and the developing unit becomes 0 (zero) is T2. It is set to T1> T3 and T1 <T2.
When an error relating to image formation occurs and it is determined that power supply should not be stopped and the image carrier driving motor is stopped, the second process executed independently of the other process stop sequence The image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so as to execute a second process stop sequence that does not include the operation control of the motor. In the process stop sequence 2, after the exposure drive motor control signal is turned off, the voltage application means control signal is turned off. Therefore, there is no exposure on the surface of the image carrier that is not charged, and it is possible to prevent the toner from adhering to the surface of the image carrier having a lowered potential and the accompanying increase in toner consumption. In addition, the charged image carrier can be prevented from passing through the developing device when a developing bias is not applied, the carrier can be prevented from rising, and the image carrier surface can be worn or scratched. Can be prevented. Therefore, the image forming apparatus can stably form an image.
[Brief description of the drawings]
FIG. 1 is a diagram showing an image forming apparatus 21 according to an embodiment of the present invention.
FIG. 2 is a block diagram of the image forming apparatus 21. FIG.
3 is a circuit diagram showing a main motor drive control unit 51, a polygon motor drive control unit 52, and a process voltage control unit 53. FIG.
4 is a flowchart showing a stop operation when an error occurs in an image forming operation of the image forming apparatus 1. FIG.
FIG. 5 is a timing chart showing a first process stop sequence.
FIG. 6 is a timing chart showing a second process stop sequence.
FIG. 7 is a timing chart showing a third process stop sequence.
FIG. 8 is a timing chart showing an emergency stop sequence when an error occurs in an image forming operation of a conventional image forming apparatus.
[Explanation of symbols]
7 Laser scanner unit (LSU)
8 Photoconductor 9 Developer 10 Transfer device 12 Charger 14 Feed roller 17 Fixing roller 21 Image forming apparatus 50 Control unit 51 Main motor drive control unit 52 Polygon motor drive control unit 53 Process voltage control unit 54 High voltage generation unit 55 Main Motor 56 Polygon motor 57 Step-up transformer 58 Load 59 Power source C1, C2 Capacitors D1, D2 Diode P Recording paper P1 Time when rotation of the photosensitive member 8 stops P2 Time when the main charger V2a becomes 0 and time when the developing bias V2b becomes 0 Time point R1, R2 when exposure by P3 LSU7 stops Resistor S1 Main motor control signal S2 Process voltage control signal S3 Polygon motor control signal T1 Period T2 between main motor control signal S1 off and time P1 Process voltage control signal S2 off From time to time P2 Period T3 period V1 main motor drive voltage from the off-time of the polygon motor control signal S3 to the point P3 V2a main charger V2b developing bias V3 polygon motor drive voltage

Claims (1)

An image carrier;
An image carrier driving motor for rotationally driving the image carrier;
Charging means for charging the surface of the image carrier to a predetermined potential by the voltage from the voltage applying means;
Exposure means for exposing the surface of the image carrier to form an electrostatic latent image corresponding to the image signal;
An exposure drive motor for driving the exposure means;
Developing means for developing the electrostatic latent image by a voltage from the voltage applying means to form a visible image;
A paper feed roller for feeding a recording paper for transferring a visible image to a transfer area;
Control means for controlling the image carrier driving motor, the exposure driving motor and the voltage applying means by each control signal;
In an image forming apparatus including an image carrier driving motor, an exposure driving motor, a voltage applying unit, and a power source for supplying a power source voltage to the control unit,
The control unit includes a step-up transformer, a diode, a capacitor, and a resistor, and among these, the capacitor is configured such that the operation timing of the image carrier driving motor, the exposure driving motor, the charging unit, and the developing unit can be adjusted,
When an error relating to image formation occurs , it is determined that the supply of power should not be stopped, and when the image carrier driving motor is driven, a first process executed independently of other process stop sequences A first process stop sequence including a process stop sequence including operation control of the motor is executed, and in the first process stop sequence, control signals for the image carrier drive motor and the exposure drive motor are turned off. After that, the control signal of the voltage applying means is turned off,
This is a third process stop sequence that is executed independently of other process stop sequences when an error relating to image formation that may cause the operator to touch the inside of the apparatus occurs. If it is determined that the image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so that the power supply voltage is turned off immediately and the third process stop sequence is executed, the image carrier drive motor The period from when the control signal is turned off until the rotation of the image carrier stops is T1, and the period from when the control signal of the exposure drive motor is turned off until the exposure by the exposure means is stopped is T3. When the period from when the control signal of the applying unit is turned off to when the applied voltage to the charging unit and the developing unit becomes 0 (zero) is T2. Is set to T1> T3 and T1 <T2,
When an error relating to image formation occurs and it is determined that the supply of power should not be stopped and the image carrier driving motor is stopped, the second process is executed independently of other process stop sequences. The image carrier drive motor, the exposure drive motor, and the voltage application means are controlled by each control signal so as to execute a second process stop sequence that does not include the operation control of the motor . In the process stop sequence of No. 2, the image forming apparatus is characterized in that the control signal of the voltage applying unit is turned off after the control signal of the exposure drive motor is turned off .

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