JPH0728311A - Automatic cleaning device for electrifier - Google Patents

Abstract

PURPOSE:To accurately detect that a motor stops driving halfway so as to improve reliability by calculating the number of revolution of the motor based on a signal from a motor driving condition detecting means, and calculating the position of the reciprocating moving body based on the number of revolution. CONSTITUTION:Since the motor 8 drives a body to be transferred so as to move the reciprocating moving body, the moving amount of the reciprocating moving body is proportional to the number of revolution of the motor 8. The driving current of the motor 8 is generally in proportion to the number of revolution. Consequently, the driving current of the motor 8 is detected by a current detecting circuit, and a CPU calculates the moving amount of the reciprocating moving body based on a signal as a software is used, so that the present location of the reciprocating moving body can be obtained. That is, the cleaning condition on a charge wire 2 by means of a cleaning pad 3 can be monitored. The present location of the reciprocating moving body can be grasped in this way, so that the cleaning condition can be obtained by outputting information to a host computer, a displaying unit, etc.; therefore, the loss of time for forming an image can be reduced as a result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic charger cleaning device for automatically cleaning a charge wire in a charger used in an electrophotographic image forming apparatus such as a laser printer or a copying machine.

[0002]

2. Description of the Related Art Conventionally, a charger (charger) of an electrophotographic image forming apparatus is in an environment where it is easily contaminated by developer dust. In particular, when the charge wire forming the charger becomes dirty, its discharge characteristic changes and the image forming conditions change, so that a proper image cannot be obtained.

Therefore, various charge wire cleaning devices have been implemented and proposed. For example, in the automatic charger cleaning device disclosed in Japanese Patent Laid-Open No. 61-292654, if the motor lock signal does not occur within the specified time or within the specified time, it is determined that the operation is abnormal, cleaning is stopped, and the copying operation is stopped. Further, in JP-A-61-292655, in the automatic cleaning device for the charger equipped with the home position detecting means, when the home position (fixed position) signal is off, There is disclosed a technique of returning the cleaning member to the home position and controlling the cleaning operation after the home position signal is detected. Further, Japanese Patent Laid-Open No. 1-284874 discloses wire cleaning for a corona discharger. In the device, the cleaning member is reciprocated along the transfer rod parallel to the wire, the cleaning member is returned to the home position when the power is turned on, and the home position is returned within the specified time. If not return to (place) is shown a technique which is adapted to that effect display.

[0004]

The above-mentioned automatic charger cleaning device is effective as a means for preventing the contamination of the charge wire, but there is a problem that an abnormal image is formed when the cleaning member is stopped during cleaning. A method has been adopted in which a sensor for detecting the time, a sensor for detecting that the cleaning member has reached the home position or the offset position, and the like are provided so that the home position is always returned at the time of image formation.

However, in the method using the sensor,
If the position detection sensor itself fails and normal detection cannot be performed, for example, if the home position sensor remains on and fails, it is determined that the cleaning member is in the home position even if it is stopped midway, and an abnormal image is displayed. There was a problem that it was output.

In the time monitoring method, the reference time range is, for example, 5 to 30 seconds when an abnormality occurs when a motor restraint signal is output within 5 seconds or less or 30 seconds or more after the start of cleaning. Even if it stops within the middle position due to an increase in the load, it is considered as a normal end, and there is a problem that an abnormal image is output.

The object of the present invention is to enable early detection of an abnormality in the home position detection means and to reduce the stoppage of the cleaning member as much as possible. An object of the present invention is to provide an automatic charger cleaning device in an image forming apparatus having high reliability that detects this with high accuracy.

[0008]

To achieve the above object, the present invention provides a reciprocating body for supporting a cleaning pad in a state where the cleaning pad is pressed against the charge wire, and a reciprocating body for the charge wire. A transfer body for reciprocating substantially parallel to each other, a motor for driving the transfer body, a motor drive state detection means for detecting a drive current and a restrained state of the motor, and a timekeeping means for timing the cleaning time. In the provided automatic charger cleaning device, means for calculating the number of rotations of the motor from the signal from the motor drive state detection means and further calculating the position of the reciprocating body based on this number of rotations are provided. To do.

Further, from the signal from the motor drive state detecting means, the rotation speed of the motor is calculated every preset time, and the moving amount and the average moving speed of the reciprocating moving body after the cleaning is started are calculated. Further, it is characterized by further comprising means for calculating an estimated remaining time until the end of cleaning and displaying the estimated remaining time or sending it to the image controller.

Further, if the number of rotations of the motor from the start of cleaning calculated from the signal from the motor driving state detection means to the restrained state deviates from the preset number of rotations, it is determined that the operation is abnormal. It is characterized in that it is provided with means for judging and stopping the image forming operation, displaying that an abnormality has occurred, or sending an error signal to the image forming controller.

Further, the operation abnormality detection by comparing the number of rotations of the motor required until the end of cleaning with the number of rotations until the signal of the motor restraint state is output is compared with the cleaning period from the home position to the offset position. , The cleaning period from the offset position to the home position is performed independently.

Further, various numerical values such as the number of revolutions, the amount of movement, and the remaining time calculated from the signal from the motor driving state detecting means are
It is characterized in that a non-volatile storage means for storing each calculation is provided.

Further, when the power is turned off during cleaning and then turned on again, based on the data recorded in the non-volatile storage means, the cleaning pad has a preset distance in the opposite direction to the moving direction when the power is turned off. It is characterized in that the cleaning is carried out by moving it again and then switching to the moving direction when the power is turned off again.

Further, a home position detecting means for detecting the presence of the cleaning pad at the home position is provided, and the cleaning pad started from the home position can reach a distance surely outside the detection range of the home position detecting means. At the time when it is calculated that it has moved, the signal of the home position detecting means is checked, and as a result, when the cleaning pad is still present, it is judged that the home position detecting means is abnormal, Is displayed, or
Alternatively, the image forming controller is provided with means for sending an error signal.

[0015]

According to the above means, the reciprocating body is moved by driving the transfer body by the motor, so that the moving amount of the reciprocating body is proportional to the rotation speed of the motor. Further, generally, the drive current of the motor is proportional to the rotation speed of the motor. Therefore, by detecting the drive current of the motor and calculating the amount of movement of the reciprocating moving body from the signal by software, the current position of the reciprocating moving body can be known and the cleaning state can be monitored. .

Further, the motor drive state detecting means detects the motor drive current at preset time intervals, derives the number of rotations of the motor and the moving distance of the reciprocating movable body at each set time, and based on these outputs. Further, the average moving speed of the reciprocating moving body and the estimated remaining time until the end of cleaning can be calculated. Then, by displaying the estimated remaining time, it is possible to establish a guideline for the waiting time until the image formation is restarted.

Further, by comparing the theoretically required motor rotation speed up to the end of cleaning with the motor rotation speed required up to the actual end of cleaning, an operation abnormality can be detected, and therefore highly accurate abnormality detection can be performed. You can do it,
It is possible to prevent abnormal image output due to a defect in the control state.

Further, since the abnormality detection based on the number of rotations of the motor is independently performed for the forward path and the return path, the detection accuracy is further improved, and which path the operation abnormality has occurred can be specified, and effective information at the time of maintenance can be obtained. Can be provided.

Further, by recording the progress of the cleaning process in the non-volatile storage device, the cleaning operation can be resumed from the place where it was interrupted when the power is turned on again, even if the power is turned off during the cleaning process. It is possible to save the time until the end of cleaning and prevent the cleaning from being completed halfway.

When the power is turned on again, the reciprocating body is slightly returned in the direction opposite to the rotation direction at the time when the power was turned off, and cleaning is restarted. Since the dirt transferred from the body to the charge wire can be surely removed, deterioration of image quality can be prevented.

Further, when the home position detecting means is added, without changing other configurations,
In order to detect an abnormality in the home position detection means,
It is possible to provide a more reliable automatic charger cleaning device.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of the present invention, FIG. 2 is a configuration diagram showing a side surface state of the present embodiment, 1 is a charger main body, 2 is a known charger main body 1. Thus, the charge wire 3 stretched in this manner is a cleaning pad which is in pressure contact with the charge wire 2, 4 is a slider which is a reciprocating body which supports the cleaning pad 3 at the bottom, and 5 is screwed into the slider 4. , A feed screw which is a transfer body for moving the slider 4 substantially parallel to the charge wire 2, 6 is a driven gear fixed to the end of the feed screw 5, 7 is a drive gear which meshes with the driven gear 6, and 8 is A motor for rotationally driving the drive gear 7, 9 is a detection claw portion protruding from the slider 4, and 10 is a transmission-type photo detecting the presence or absence of the detection claw portion 9 fixed to a body side plate of the image forming apparatus not shown. Interla A home position sensor is a position detecting means including a motor or the like, 11 and 12 show the rear end block and the front end block fixed to both ends of the charger main body 1.

The slider 4 is provided with a rotatable feed screw 5
The slider 4 reciprocates along the feed screw 5 when the feed screw 5 rotates forward and backward. When the slider 4 is fed out by the rotation of the feed screw 5, the slider 4 is guided by the bent portion 1a of the charger body 1, and the cleaning pad 3 is charged by the charge wire 2.
Sandwich. In this state, the cleaning wire 3 reciprocates to clean the charge wire 2. The feed screw 5 is rotated in the normal direction by driving the driven gear 6 at the end of the feed screw 5 by the drive gear 7 mounted on the output shaft of the motor 8, that is, by the forward and reverse rotation of the motor 8. When the slider 4 returns to the home position on the front side, the detection claw portion 9 integrally attached to the upper portion of the slider 4 turns on the home position sensor 10.

FIG. 3 is a block diagram showing the configuration of the control system of this embodiment. 15 is an image forming apparatus in which this embodiment is mounted and a CPU (central processing unit) for controlling this embodiment, 16
Is a host computer connected to the CPU 15 via the controller 17, 21 is a ROM which is a memory recording a control program, 18 is an EEPROM (electrically erasable PROM) which is a memory in which various data are recorded, 19 Is a motor drive circuit for driving the motor 8, and 20 is a current detection circuit which is a motor drive state detection means for detecting a current change in the motor drive circuit 19.

The control operation in this embodiment will be described.

When the image forming apparatus is powered on, the CP
After initialization, U15 outputs a normal rotation signal to the motor drive circuit 19 for positioning the cleaning pad 3 at the home position (front side) and for checking the function of the home position sensor 10, and the motor drive circuit
19 rotates the motor 8 in the normal direction. As a result, the slider 4 moves to the rear side. This forward rotation time is stored in the ROM 21 in advance, and the motor 8 moves the slider 4 by a distance sufficient for the detection claw portion 9 to turn off the home position sensor 10.

Next, the CPU 15 outputs a signal for switching the motor drive circuit 19 to the reverse rotation direction in order to switch the rotation direction of the motor 8. As a result, the motor 8 reversely rotates,
The slider 4 moves toward the home position. When the slider 4 reaches the front end block 12, the motor 8 is locked, so that a restricted current flows through the motor 8. The CPU 15 converts the drive current of the motor 8 into a voltage by the current detection circuit 20 having a current / voltage conversion function and monitors the analog port (AN) at a predetermined time when the motor 8 is driven. When the restricted current flows through the motor 8, it is judged that the motor 8 has returned to the home position, and the driving of the motor 8 is stopped. As a result, the slider 4
Will always be in the home position during image formation and will not output an abnormal image.

FIG. 4 is a graph showing the relationship between the rotational speed and the driving current and the output torque in the DC brush motor, a vertical axis I represents the drive current, particularly I ₁ the motor 8 is constrained state ( Locking current, I _2, is a no-load current when the motor 8 is in a no-load state. Further, R on the horizontal axis represents the number of revolutions, and particularly R ₁ represents the no-load number of revolutions.

Here, the CPU 15 is an analog port (AN)
The amount of movement of the cleaning pad 3 is calculated from the current value monitored in step 1 by the following method.

As shown in FIG. 4, since the drive current value I is proportional to the rotation speed R, it can be expressed by the following relational expression.

[0032]

## EQU1 ## I = -kR + I ₁ (A). k is a proportional constant and indicates the slope of the graph. So in FIG.

[0033]

## EQU2 ## k = (I ₁ −I ₂ ) / R ₁ holds. Therefore, (Equation 1) is

[0034]

## EQU3 ## I = {-(I ₁ -I ₂ ) / R ₁ } R + I ₁ (A). From this, if converted into the relationship of the motor rotation speed viewed from the detected current value,

[0035]

## EQU4 ## R = {(I ₁ −I) / (I ₁ −I ₂ )} × R ₁ (rpm). The rotational speed of the motor 8 can be calculated by reading the drive current value I from this formula. In addition,
Since (Equation 4) is the number of revolutions per minute, both sides can be divided by 60 seconds to restore it in seconds. In addition, since the control by the CPU 15 is generally performed based on the reference clock, the sampling interval of the driving current value I is set to t (seconds), the driving current value at the time of sampling is i (A), and at the sampling time interval t. , R is the number of rotations of the motor 8
Assuming (rotation), the rotation number r can be expressed by the following equation.

[0036]

## EQU5 ## r = (I ₁ −i) / (I ₁ −I ₂ ) × R ₁ × t (rotation). By accumulating the number of rotations r, the number of rotations of the motor 8 after the start can be easily calculated.

If the feed pitch per rotation of the feed screw 5 is l, the distance x moved by the slider 4 during r rotation is

[0038]

## EQU6 ## It is represented by x = 1 × r (m) (when the rotation speed of the motor 8 and the rotation speed of the feed screw 5 are 1: 1). Therefore, the CPU 15 may add x and drive the motor 8 until the distance exceeds the detection range of the home position sensor 10.

The output voltage V of the current detection circuit 20 and the drive current value I have the following relationship when the proportional constant is k.

[0040]

## EQU7 ## V = k × I (V) By controlling in this way, the CPU 15 can easily and accurately calculate the current position of the slider 4 based on the drive current value I.

Next, operation control during cleaning will be described.

The CPU 15 makes an EEP every time an image is formed.
The maintenance counter assigned to the memory of the ROM 18 is incremented. Then, when the value of the maintenance counter becomes equal to the value representing the cleaning time of the charge wire 2 set in the ROM 21 in advance, the CPU 15 stops the image forming operation as soon as the image forming operation currently being processed is completed. Charge wire 2 for controller 17
Send the cleaning request of. Controller 17
When the request command is received, the printer notifies the host computer 16 that the printer is busy, stops receiving the image data, and sends a cleaning start command to the CPU 15. When the CPU 15 receives the start command, it outputs a signal to the motor drive circuit 19 to rotate the motor 8 in the normal direction, and the motor drive circuit 19 drives the motor 8 in the normal direction by this signal. As a result, the slider 4 cleans from the home position on the front side toward the offset position.

When the slider 4 reaches the rear end block 11, the motor 8 is in a restrained state.
A voltage corresponding to the constraint current is output from 20 to the analog port AN of the CPU 15. When the CPU 15 detects a voltage corresponding to this constraint current (hereinafter referred to as a constraint voltage),
For a preset time in ROM21 to prevent malfunction
(For example, about 0.5 seconds) Check if the restraint condition continues. When the CPU 15 detects that the restrained state has continued for the set time or longer, in order to perform cleaning from the offset position side to the home position side,
The CPU 15 outputs a signal for reversing the motor 8 to the motor drive circuit 19. If the restrained state is equal to or less than the set time, the drive on the forward rotation side is continued.

In this way, the slider 4 cleans from the offset position side to the home position side. When the slider 4 reaches the front end block 12, the current detection circuit 20 outputs the restraint voltage again, and the CPU 15 performs the same control as when reaching the rear end block 11 described above. Then, when the restraint voltage is continuously output for the set time (for example, about 0.5 seconds), the CPU 15 causes the motor 8 to rotate again.
The cleaning operation is completed by driving the slider 4 and the feed screw 5 in the normal rotation for a minute time (for example, about 0.1 second) set in M21. After cleaning, C
The PU 15 sends a cleaning end signal to the controller 17 to restart image formation.

Next, the remaining time until the end of cleaning is calculated,
The control for displaying will be described.

FIG. 5 is a schematic front view of FIG. 1, and L indicates the distance that the slider 4 moves from the home position to the offset position. Needless to say, the moving distance from the offset position to the home position is also equal to the moving distance L. Further, when the rotational speed required for the slider 4 to move one way is Rm,
This Rm is

[0047]

## EQU8 ## It can be expressed by Rm = L / l (rotation). It should be noted that 1 indicates the thread pitch of the feed screw 5 described above, and this thread pitch 1 is equal to the moving distance of the slider 4 when the feed screw 5 makes one rotation. Further, since the moving distance of the slider 4 is doubled in one reciprocating cleaning, the number of rotations of the motor 8 is 2Rm until the cleaning is completed.

When the cleaning operation is started, the CPU 15 reads the output of the current detection circuit 20 from the analog port (AN) at every arbitrary time (for example, every 20 ms), and uses the above (Equation 5) to obtain the desired time ( Rotation speed r of the motor 8 every 20 ms)
Calculate _x (x = 1, 2, ..., N). However, since the output signal of the current detection circuit 20 has a voltage value, it is necessary to perform the following conversion before calculating the rotation speed r _{x according} to (Equation 5).

[0049]

I = v / K (A) When the output voltage value of the current detection circuit 20 and the motor drive current value have a 1: 1 relationship, it is not necessary to perform the conversion according to the (expression 9). .

Next, the CPU 15 accumulates the number of revolutions r _x calculated by sampling every 20 ms, every arbitrary time (for example, every 5 seconds), or at the time when there is a request from the controller 17, The moving amount of the slider 4 from the start of cleaning and the average moving speed at that time are calculated by (Equation 10) and (Equation 11).
It is calculated by the formula.

[0051]

[Number 10] _{l x = 1 (r 1 +} r 2 + ...... + r n) (m)

[0052]

[Expression 11] V = p / nt (m / s) where l _x is the moving amount of the slider 4, and V is the average moving speed. Furthermore, the remaining time T until the end of cleaning can be calculated by the equation (12).

[0053]

[Equation 12] T = (2L-l _x ) / V In this way, the remaining time T until the end of cleaning obtained is C
The PU 15 sends it to the controller 17 or displays it on the display. When the controller 17 receives the signal of the remaining time T, it sends this value T if there is a request from the host computer 16.

By controlling in this manner, the operator can know the time until the image formation is restarted on the host computer 16 or the display, and as a result, the loss time until the printout or the copying is completed can be reduced. .

Next, the first for detecting an abnormal operation of the cleaning device
The detection means will be described.

As described above, the rotation speed of the motor 8 before the cleaning is 2Rm, and the rotation speed calculated by the CPU 15 sampling the output signal of the current detection circuit 20 from this 2Rm and the cleaning start to the end. Sum rσ (= r ₁ + r ₂
+ ... + r _n ) is compared. If the two values are different, it is determined that the operation is abnormal. A possible cause of the difference between the two values is that the slider 4 is stopped halfway due to an increase in load.

The detection accuracy of the total r r of the actual rotational speeds can be improved by reducing the interval of the sampling time t by the CPU 15. It should be noted that the sampling time of 20 ms employed in this embodiment can be set within several revolutions even if mechanical play and dimensional tolerance are included.

By monitoring the operation abnormality of the cleaning device in this way, the accuracy is several steps better than the conventional method of monitoring the movement time of the slider 4, and the slider 4 is further improved.
The position sensor for detecting the position of is not necessarily required. Therefore, the structure is relatively simple, the reliability is improved, and the cost can be further reduced. Of course, the first detection method,
It may be used together with a position sensor or time monitoring.

When an abnormality is detected, it is determined that there is a failure in the drive system such as the motor 8 and the abnormality is displayed on a display (not shown) or an error message is sent to the controller 17, and The image forming operation and the cleaning operation thereafter are stopped.

Although the method for detecting the operation abnormality of the cleaning device has been described above, there is also the second detection method described below as the abnormality detection method.

First, the CPU 15 obtains the total number r.sigma. Of rotation speed for each of the two routes from the home position to the offset position (outward route) and from the offset position to the home position (return route). Then, when the one-way portion ends, that is, when the output of the current detection circuit 20 reaches the restricted current value, the rotation speed R required for one-way cleaning,
The actual rotation number rσ is compared. If the two values are different, it is determined that the operation is abnormal. The process after the abnormality is detected is the same as the process in the first detecting method of the abnormal operation described above.

By detecting the operation abnormality of the cleaning device in this way, it becomes possible to detect the abnormality in the moving range which is half of that of the first detection method. Therefore, the error is halved,
The detection accuracy can be further improved. Further, when an abnormality occurs on the outward path, the abnormality detection time is halved, so the loss time is reduced as compared with the first detection method. Furthermore, it is possible to distinguish whether the operation abnormality has occurred on the outward path or the return path. This is very advantageous for maintenance after the occurrence of an abnormality.

In the first and second detection methods, the abnormality is detected by monitoring the number of rotations of the motor 8, but the same effect can be obtained in the comparison by the moving distance. In this case, by outputting distance information (distance from home position side or offset position side to abnormal position) indicating the position where the abnormality occurred to the display unit or controller 17 etc. when an abnormal condition occurs, It becomes easier to determine the point of occurrence.

Next, the first control method when the power is turned off during cleaning and turned on again will be described. In the present embodiment, the CPU 15 uses the above-described calculation method based on the signal from the current detection circuit 20 to calculate the motor rotational speed r _n after the motor 8 is started, the moving distance l _{x of} the slider 4, and the remaining amount. The data indicating the time T and the direction in which the vehicle is currently moving is E for each sampling and each calculation.
It records in EPROM18.

By doing so, even if the power is turned off during cleaning, the data immediately before the power is turned off is stored in the EEPROM.
It will be recorded in 18. Therefore, when the power is turned on next time, the CPU 15 can grasp where the cleaning is interrupted by reading the data in the EEPROM 18.

When the CPU 15 detects that the cleaning is interrupted, the CPU 15 restarts the cleaning based on the data recorded in the EEPROM 18. Specifically, the motor 8 is moved in the same direction as the rotation direction data recorded in the EEPROM 18.
Is driven, and the rotation speed after restart is added to the rotation speed data that is also recorded. After that, the charge wire 2 is cleaned by performing the control described above. In this way, even if the power is turned off during cleaning, the wire can be reliably cleaned in the minimum cleaning time, and good image quality can be maintained.

Next, the second control method when the power is turned off during cleaning and turned on again will be described.

In the second control method, the power is first turned on again, and then C
Based on the rotation direction data in the EEPROM 18, the PU 15 is in the direction opposite to the direction indicated by the rotation direction data for a certain time.
(For example, about 0.5 seconds) or after rotating the motor 8 by a distance, the motor 8 is reversely rotated (direction indicated by the rotation direction data) to perform the remaining cleaning. Here, the rotational direction data in the EEPROM 18 is not rewritten during the reverse rotation cleaning drive by the motor 8.

By doing so, for example, even if the power-off time is long and the dirt on the cleaning pad 3 has been transferred to the charge wire 2, the dirt can be removed by reverse re-cleaning. Can be reliably cleaned without leaving any dirt.

FIGS. 6 and 7 are timing charts for cleaning in this embodiment, and an operation for detecting an abnormality of the home position sensor 10 will be described with reference to FIGS.

In the cleaning device equipped with the home position sensor 10 for detecting that the slider 4 is in the home position, first, when the power is turned on and the printer engine cover is opened / closed, the CPU 15
The output of the home position sensor 10 is checked with the first check time (↑ in FIG. 7) when the slider 4 is calculated to be far enough away from the home position sensor 10. Further, the output of the home position sensor 10 is checked with the second check time (↑ in FIG. 7) at the time when the restraining current when the motor 8 is reversed and the slider 4 returns to the home position is detected. If the output at the first check time is on (the slider 4 is present) or the output at the second check time is off (the slider 4 is not present), the home position sensor 10 or judge that there is a failure in the drive system such as the motor 8 and display the abnormality on a display not shown,
An error message is sent to the controller 17, and at the same time, the subsequent image forming operation and cleaning operation are stopped.

Further, even during the cleaning operation, the state of the home position sensor 10 is detected, so that the time when the offset side restraining current is detected (↑ in FIG. 6) and the restraining signal when returning to the home position are detected. The output of the home position sensor 10 is checked at the same time (↑ in FIG. 6), and if the same abnormality as described above occurs, the same error processing is performed. Further, during the period from the start of cleaning to the end of cleaning, the output of the home position sensor 10 may be sampled at preset time intervals, and the abnormality of the home position sensor 10 that occurred during cleaning can be detected early, so It is valid.

Other cleaning operations and the like are the same as the above-mentioned control.

By using the method as described above, it is possible to easily determine the abnormality of the home position sensor 10.

[0075]

According to the present invention constructed as described above, the following effects can be obtained.

According to the structure of claim 1, the current position of the reciprocating moving body can be grasped only by the processing of software for calculating the motor rotation speed without requiring a complicated mechanism, and therefore the information is displayed on the host computer and the display. By outputting to a device, the user can know the cleaning status,
As a result, the loss time for image formation can be reduced.

According to the second aspect of the invention, a complicated mechanism is not required, and the number of rotations of the motor, the moving distance of the reciprocating moving body, and the remaining time until the end can be accurately grasped by only software processing. Since the information is output to the host computer, the display, etc., the user can know the waiting time until the end of cleaning, and as a result, the loss time for image formation can be reduced.

According to the third aspect of the present invention, since the operation abnormality can be detected by comparing the theoretical value and the actual value of the motor rotation speed required until the end of cleaning, it is possible to detect the abnormality with high accuracy and to prevent a control problem. The abnormal image output due to is eliminated. Also, CPU
Since the detection accuracy can be adjusted by changing only the sampling time of, the control according to the cleaning device becomes easy,
It is also advantageous in terms of cost.

According to the fourth aspect of the present invention, since the abnormality detection based on the motor rotation speed is independently performed for the forward path and the return path, the detection accuracy is further improved and it is possible to specify in which path the operation abnormality has occurred. Since effective information can be provided at the time of maintenance, quick response is possible.

According to the structure of claim 5, by recording the progress of the cleaning in the non-volatile storage device, even if the power is turned off during the cleaning, even if the power is interrupted when the power is turned on again. Since cleaning can be restarted, it is possible to save time until the end of cleaning and prevent the cleaning from ending halfway.

According to the structure of claim 6, when the power is turned on again, the reciprocating body is slightly returned in the direction opposite to the rotating direction at the time when the power is turned off, and then the cleaning is restarted.
Since the dirt transferred from the reciprocating body to the charge wire due to the long power-off time can be reliably removed, deterioration of image quality can be prevented.

According to the structure of claim 7, in the case where the home position sensor is added, the abnormality of the home position sensor can be detected without changing the other structure, so that higher reliability is achieved. A cleaning device can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of an automatic charger cleaning device in an image forming apparatus of the present invention.

FIG. 2 is a configuration diagram showing a side surface state of the present embodiment.

FIG. 3 is a block diagram showing a configuration of a control system of this embodiment.

FIG. 4 is a graph showing a relationship between a motor rotation speed and a drive current.

FIG. 5 is a configuration diagram showing a front state of the present embodiment.

FIG. 6 is a cleaning timing chart of the present embodiment.

FIG. 7 is a cleaning timing chart of the present embodiment.

[Explanation of symbols]

1 ... Charger main body, 2 ... Charge wire, 3 ... Cleaning pad, 4 ... Slider (reciprocating body), 5
... Feed screw (transport body), 8 ... motor, 9 ... detection claw,
10 ... Home position sensor (fixed position detection means), 11
... rear end block, 12 ... front end block, 15 ... CPU (central processing unit), 16 ... host computer, 17 ... controller, 19 ... motor drive circuit, 20 ... current detection circuit (motor drive state detection means) .

Claims (7)

[Claims] 1. A reciprocating body for supporting the cleaning pad in a state where the cleaning pad is pressed against the charge wire, a transfer body for reciprocating the reciprocating body substantially parallel to the charge wire, and the transfer. In a charger automatic cleaning device comprising a motor for driving a body, a motor drive state detection means for detecting a drive current and a restrained state of the motor, and a time measurement means for measuring a cleaning time, the motor drive state detection means An automatic charger cleaning device comprising means for calculating the number of rotations of the motor from the signal and further calculating the position of the reciprocating body based on this number of rotations. 2. The number of revolutions of the motor is calculated from a signal from the motor driving state detecting means at every preset time, and the moving amount and the average moving speed of the reciprocating moving body after the cleaning is started are calculated. 2. The automatic charger cleaning device according to claim 1, further comprising means for calculating an estimated remaining time until completion of cleaning and displaying the estimated remaining time or sending the estimated remaining time to an image controller. 3. When the number of rotations of the motor from the start of cleaning calculated from a signal from the motor drive state detection means to the time of becoming in a restrained state deviates from the preset number of rotations, an operation abnormality is detected. 2. The automatic charger cleaning device according to claim 1, further comprising means for judging and stopping the image forming operation, displaying that an abnormality has occurred, or sending an error signal to the image forming controller. 4. A motor rotation speed required until cleaning is completed,
The operation abnormality detection by comparing the number of rotations until the motor restraint signal is output is independently performed in the cleaning period from the home position to the offset position and the cleaning period from the offset position to the home position. The automatic charger cleaning device according to claim 3, wherein 5. A non-volatile storage means is provided for storing various values such as the number of revolutions, the amount of movement, and the remaining time calculated from the signal from the motor drive state detection means each time the values are calculated. The automatic charger cleaning device according to 1, 2, 3 or 4. 6. A distance set in advance in a direction opposite to the moving direction of the cleaning pad based on the data recorded in the non-volatile memory when the power is turned off during cleaning and then turned on again. 6. The automatic charging device cleaning device according to claim 5, wherein the cleaning is performed by moving the cleaning device by only moving the cleaning device and then switching to the moving direction when the power is cut off again. 7. A home position detecting means for detecting the presence of the cleaning pad at the home position is provided, and the cleaning pad started from the home position extends to a distance surely outside the detection range of the home position detecting means. At the time when it is calculated that it has moved, the signal of the home position detecting means is checked, and as a result, when the cleaning pad is still present, it is determined that the home position detecting means is abnormal, 2. The automatic charger cleaning device according to claim 1, further comprising means for displaying that an error has occurred or sending an error signal to the image forming controller.