JP2000356891A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously execute image forming operation without stopping the image forming operation to the utmost at the time of leakage by providing a cleaning driving control part for driving a wire cleaning means in the case of temporarily stopping voltage supply by a voltage supply part. SOLUTION: Whether or not it is a state where high voltage (primary) is outputted is judged. In the case of judging that it is the outputted state, a high voltage on-signal is outputted from a CPU 201 to a high voltage unit 213 through an I/O port 206. Whether or not leakage is not caused is always monitored. When a high voltage (primary) error signal is outputted, a primary electrification protective circuit 401 acts and high voltage output is stopped regardless of the signal from the CPU. Then, an error signal 410 is outputted to the CPU 201, and the CPU 201 receiving the signal 410 sets a high voltage on-signal in an off state. The CPU 201 drives a primary electrifier cleaning motor 402 so as to clean the wire of a primary electrifier 113. After finishing the cleaning, premulti-rotating action is started and the high voltage is outputted again.

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 for charging the surface of a photosensitive drum by applying a high voltage to a wire.

[0002]

2. Description of the Related Art Conventionally, for example, in a digital copying machine or the like, a so-called reversal developing system has been used. In the reversal development method, a charge of the same polarity as that of the toner is charged on a photosensitive drum by a primary charger, and a light such as a laser is applied to the photosensitive drum to remove the charge of a portion hit by the light. In this method, an image is formed by applying toner to this portion.

In a copying machine using the above-described reversal development system, a high voltage circuit for primary charging stops the supply of power when an abnormality such as leakage or open in the primary charger is detected, and an image forming operation is performed. To stop.

[0004]

By the way, these days,
In many cases, the image forming section including the primary charger is detachable from the main body of the machine, and there is an increasing number of cases where dust or dust adheres to the primary charger when the image forming section is pulled out. When dust or dust adheres to the wire of the primary charger as described above, the primary charger often causes the above-described leak. However, in such a case, it is known that an image can be formed again only by cleaning the wire of the primary charger.

Therefore, according to the present invention, the image forming operation can be continuously performed without stopping the image forming operation as much as possible by cleaning the wire at the time of leakage caused by contamination of the wire of the primary charger. It is an object to provide such an image forming apparatus.

[0006]

In order to achieve the above object, the present invention provides a primary charging means having a charging wire and a voltage supply for supplying a voltage to the charging wire; An image forming apparatus comprising: a photosensitive member to be obtained; and exposing and developing the charged photosensitive member to form a toner image, and transferring the toner image to a transfer material to form an image. A wire cleaning unit that can be cleaned, a leak detection unit that detects a leak in the primary charging unit and supplies a detection signal when a voltage is supplied by the voltage supply unit, and supplies the voltage based on a detection signal from the leak detection unit. A voltage supply control unit for temporarily stopping and resuming the supply of voltage by the unit; and a cleaning unit for driving the wire cleaning unit when the voltage supply by the voltage supply unit is temporarily stopped. Characterized by comprising a drive control unit.

A voltage stop control unit for stopping the supply of the voltage by the voltage supply unit based on a detection signal from the leak detection unit after the voltage supply by the voltage supply unit is restarted; It is also possible to provide an error message output means for outputting an error message when the voltage supply is stopped.

According to the above configuration, if a leak occurs in the primary charging unit when the voltage is supplied by the voltage supply unit, the supply of the voltage by the voltage supply unit is temporarily stopped, and the charging wire is cleaned during that time. Image formation is immediately resumed.

Further, if the primary charging means leaks again after the image formation is restarted, the voltage supply by the voltage stop control unit is stopped, and the image formation is interrupted.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of the image forming apparatus will be described with reference to FIG.

FIG. 1 is a sectional view illustrating the structure of an image forming apparatus according to an embodiment of the present invention. Reference numeral 101 denotes an original table glass, and the originals fed from the automatic original feeder 160 are sequentially placed at predetermined positions on the original table glass 101. An original illumination lamp 102 composed of, for example, a fluorescent lamp exposes an original placed on the original platen glass 101. Reference numerals 103, 104, and 105 denote scanning mirrors, which are housed in an optical scanning unit (not shown), and which reciprocate and reflect light reflected from a document to the CCD unit 1.
06. A CCD unit 106 is an imaging lens 107 that forms reflected light from a document on the CCD, for example, a CCD.
, A CCD driver 109 for driving the image sensor 108, and the like. The image signal output from the image sensor 108 is converted into, for example, 8-bit digital data and then input to the controller 150. Reference numeral 110 denotes a photosensitive drum (photoreceptor), which is discharged by a pre-exposure lamp 112 in preparation for image formation. Reference numeral 113 denotes a primary charger, which is a photosensitive drum 11
0 is uniformly charged. Reference numeral 117 denotes a laser unit serving as an exposure unit, which is constituted by, for example, a semiconductor laser or the like.
Controller unit 150 that performs image processing and controls the entire apparatus
The photosensitive drum 110 is exposed based on the image data processed in the step (1) to form an electrostatic latent image. Reference numeral 118 denotes a developing device,
A black developer (toner) is stored. Reference numeral 119 denotes a buffer unit that stores toner, and toner is supplied from a detachable toner storage container (hereinafter, referred to as a cartridge) set at 120. Buffer unit 119
Is supplied to the developing device according to the amount of toner in the developing device. A pre-transfer charger 121 applies a high voltage before transferring the toner image developed on the photosensitive drum 110 to a sheet. 122, 124, 126, 128, 1
Reference numeral 30 denotes a paper feed unit, and each paper feed roller 123, 12
5, 127, 129, and 131, the transfer paper is fed into the apparatus, temporarily stops at the position where the registration roller 132 is provided, and the timing of writing with the image formed on the photosensitive drum 110 is set, and re-feeding is performed. Sent. A transfer charger 133 transfers the toner image developed on the photosensitive drum 110 to a fed transfer sheet. Reference numeral 134 denotes a separation charger, which transfers the transfer paper after the transfer operation to the photosensitive drum 110.
Separate more.

The toner remaining on the photosensitive drum 110 without being transferred is collected by a cleaner 111. 135
Is a conveyor belt that conveys the transfer paper after the transfer process to the fixing device 136, where the transfer paper is fixed by, for example, heat. 13
Reference numeral 7 denotes a flapper, which controls the transfer path of the transfer sheet after the fixing process to be performed in either the staple sorter 145 or the reversing path 139. The sheets discharged to the staple sorter 145 are sorted into bins, and the staple unit 146 is instructed by the controller unit 150.
Performs stapling. The reversing path 139 is used when performing face-down discharge and double-sided copying. When performing face-down discharge, the reversing unit 139 reverses the paper before discharging. When performing double-sided copying, the reverse pass 139 is used.
To the double-sided path 144. Reference numerals 140 to 142 denote paper feed rollers which transport the re-transfer paper on the duplex path 144 to the paper feed roller 143. 140-14 retransfer paper
The paper is conveyed by the paper feed rollers 2 and 143 at a timing with the transfer paper fed from the paper feed unit, and is conveyed again to the position where the registration roller 132 is provided.

The controller unit 150 includes a microcomputer, an image processing unit, and the like, which will be described later, and performs the above-described image forming operation in accordance with an instruction from the operation panel 151.

Next, the mechanism of the controller 150 in the image forming apparatus will be described. FIG. 2 is a block diagram showing the controller 150 in the image forming apparatus of the present invention.

Reference numeral 201 denotes a C for controlling the entire image processing apparatus.
It is a PU, and sequentially reads and executes programs from a read-only memory 203 (ROM) that stores a control procedure (control program) of the apparatus main body. An address bus and a data bus of the CPU 201 are connected to respective loads via a bus driver circuit and an address decoder circuit of the CPU 202. Reference numeral 204 denotes a random access memory (RAM) which is a main storage device used as storage for input data, a work storage area, and the like.

Reference numeral 205 denotes a hard disk for image data.
Data input from the CCD unit and subjected to image processing is stored. The image data is also stored when connected to a network or the like.

Reference numeral 206 denotes an I / O port, which is an operation panel 151 for displaying the status of the apparatus using liquid crystal or LEDs by key input by an operator, and motors for driving a paper feed system, a transport system, and an optical system. 207, clutches 208, solenoids 209, and paper load sensors 210 for detecting the paper being conveyed. In addition,
A toner sensor 211 for detecting the amount of toner in the developing device is arranged in the developing device 118 shown in FIG. 1, and an output signal thereof is input to the I / O port 206. Further, signals of switches 212 for detecting the home position of each load, the open / closed state of the door, and the like are also input to the I / O port 206. Reference numeral 213 denotes a high-voltage unit, and the primary charger 113, the developing device 118, the pre-transfer charger 121, the transfer charger 133, and the separation charger 134 in accordance with instructions from the CPU.
Output high pressure to

An image processing unit 215 receives an image signal output from the CCD unit 106, performs image processing to be described later, and performs laser processing on the laser unit 1 in accordance with image data.
And 17 control signals. The laser beam output from the laser unit 117 irradiates and exposes the photosensitive drum 110, and at the same time, the light emission state is detected by a beam detection sensor 214 which is a light receiving sensor in a non-image area, and the output signal is sent to an I / O port. Is entered.

Next, the procedure of image processing by the image forming apparatus will be described. FIG. 3 is a conceptual diagram showing processing in the image processing unit 215 in the controller unit 150.

The image data converted into an electric signal by the image pickup device 108 is first sent to a shading circuit 301 in the image processing section 215, where the variation between pixels is corrected. Thereafter, the data is sent to the scaling circuit 302, where the data is thinned out at the time of reduced copy, and the data is interpolated at the time of enlarged copy. Next, the image data is sent to the edge enhancement circuit 303, and second differentiation is performed in, for example, a 5 × 5 window to perform edge enhancement of the image. Subsequently, the data is sent to the γ conversion circuit 304. This circuit 304
Then, data conversion is performed by table search. That is, the image data, which was luminance data, is converted into density data for printer output. The image data converted into the density data is input to the binarization processing unit 305. Here, multi-value data is converted into binary data by, for example, the ED method. The binary-converted image data is sent to the compression / decompression unit 307 via the memory controller 306 and is compressed. Further, the compressed image data is transmitted to the hard disk 3 via the IDE controller 308.
09.

On the other hand, when the image data in the hard disk 309 is output, the data is input to the compression / decompression unit 307 via the IDE controller 308, where it is decompressed and stored in the image memory 310 via the memory controller 306. Evacuate. Here, the data is sequentially output in synchronization with the laser unit. These image data are input to a PWM circuit in order to convert them into a signal of laser emission intensity, and a pulse width according to the image density is output to the laser unit.

Next, with reference to FIG. 4, a description will be given of a wire cleaning unit and the like, which is a point of the present invention. FIG. 4 is a diagram illustrating a configuration of a high-pressure unit, a wire cleaning unit, and a control unit (CPU, I / O).

In the case of high-voltage output in the sequence of the machine, the CPU 201 turns on the I / O port 206 via the I / O port 206.
The high-voltage unit 213 outputs a signal to the high-voltage unit 213 (voltage supply unit). The high-voltage unit 213 receives the signal so that the primary charger 11 connected to the high-voltage unit 213 is output.
A high voltage is output to 3 (primary charger 13 and high voltage unit constitute "primary charging means"). At the same time, the primary charging protection circuit 401 operates. C in this protection circuit 401
OMP1 and COMP2 (leak detecting means) are comparators for detecting open and leak, respectively.
It becomes "High" when open and leak are detected. Thereby, when an open or leak is detected, the capacitor C is charged with the time constant of the resistor R and the capacitor C,
When the voltage reaches a certain level, the thyristor Q (voltage supply control unit) is turned on, the primary charging circuit is stopped, and at the same time, the error signal 410 is transmitted to the control unit (including the CPU 201) 403.
Send to

Further, the control unit 403 also performs cleaning motor control (cleaning drive control unit). Similarly to the high-voltage output, when the CPU 20 needs to perform cleaning in a sequence (for example, when the power is turned on or after 2,000 sheets have been copied), the CPU 20 is activated.
1 is operated by the driver on the control unit 403 based on the ON signal.

FIG. 5 is a perspective view of the primary charger. The primary charger cleaning motor 4 is controlled by the driver IC on the control unit 403.
When the motor 02 is driven, the motor 402 rotates the screw 503 through the gear 504. Accordingly, the wire cleaning unit 502 is driven along the axial direction of the screw 503. By reversing the driving direction of the cleaning motor 402, the operation direction of the wire cleaning unit 402 changes in the directions indicated by arrows A and B in the figure. Wire cleaning unit 502
Is in contact with the wire 501 of the primary charger 113, and the wire 50 is driven by the wire cleaning unit 502.
1 is to be cleaned. The home sensor switch 505 detects that the wire cleaning unit 402 is at the home position.

Next, a detailed operation of the sequence at the time of detecting a high pressure leak will be described with reference to the flowchart of FIG. The image forming apparatus may output a high voltage (primary) in various cases. For example, during front multi-rotation when the power is turned on, a door such as a front door is opened and closed, or during front multi-rotation when the image forming apparatus transitions from a residual heat mode to a standby state, during image formation, and the like. There is. The sequence described below is performed at the time of all these high-voltage outputs.

First, in S1, it is determined whether or not a high voltage (primary) state is to be output for the various reasons described above.
If it is determined that the state is to be output, the CPU 201
Outputs a high voltage ON signal to the high voltage unit 213 via the I / O port 206. In S2, whether or not a leak has occurred is monitored as described with reference to FIG. Here, after the high voltage output is performed without an error signal being generated, the high voltage output may be terminated (S3,
For example, when the previous multi-rotation is completed or the image forming sequence is completed), the high pressure leak detection sequence is completed.

On the other hand, if a high-voltage (primary) error signal is output in S2 ("High"; abbreviated as "H" in FIG. 6), the primary charging protection circuit 401 operates, and the high-voltage (primary) error signal is output regardless of the CPU signal. The output is stopped (S4). Then, the error signal 4 is sent to the CPU 201 as described above.
10 (FIG. 4), and upon receiving this, the CPU 201 turns off the high voltage ON signal. CPU 201
Drives the primary charger cleaning motor 402 to clean the wire 501 of the primary charger 113 (S5). After the cleaning is completed, the multi-rotation operation is started, and the high pressure is output again (S
6). Then, again in S7, it is determined whether or not a leak has occurred as in S2. Here, if the previous multi-rotation has been completed without an error (S8), the process returns to S1 again and waits until a high-pressure (primary) output is to be performed. For example, if the sequence is performed during image formation, S1 and S2 are performed again to perform the recovery process. If no error occurs, the process proceeds to S3, and all the processes are completed.

If an error is detected again in S7, the operation proceeds to S9, in which the operation of the image forming apparatus is stopped, and the operation panel 15
1 (error message output means) or the like, a message which is an error display is displayed (S10), and the error detection sequence ends.

As described above, in the image forming apparatus of the present embodiment, when a leak occurs due to contamination of the wire 501 of the primary charger 113, the leak is detected and the wire 501 is detected.
Can be performed immediately, and the image forming operation can be continuously performed without stopping the image forming operation as much as possible.

By discriminating the error signal at the time of opening and the error signal at the time of leakage, it is possible to perform cleaning only at the time of leakage and stop the image forming apparatus without cleaning at the time of opening. For example, in this case, in FIG. 6, a process S2 '(not shown) for determining whether the error signal is a signal at the time of an open signal or a signal at the time of a leak is performed between S2 and S4. In that case, go to S9.
If it is at the time of the leak, it is sufficient to enter S4.

[0032]

As described above, according to the present invention, at the time of leakage caused by contamination of the charging wire, the supply of the voltage by the voltage supply unit is temporarily stopped, and the charging wire is cleaned during that time. Thereafter, since the image formation is immediately resumed, the image formation operation can be continuously performed without stopping the image formation operation as much as possible.

Further, if the primary charging means leaks again after the image formation is restarted, the voltage supply by the voltage stop control unit is stopped, the image formation is interrupted, and an error message is output. In other words, in the event of an abnormality of the apparatus that cannot be recovered by the cleaning of the charging wire, the image forming operation can be safely stopped, and measures such as repair can be taken promptly.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a configuration of an image forming apparatus according to the present invention.

FIG. 2 is a block diagram showing a controller unit 150.

FIG. 3 is a view for explaining processing in an image processing unit 215.

FIG. 4 is a diagram illustrating a configuration of a high-pressure unit, a wire cleaning unit, and a control unit.

FIG. 5 is a perspective view of a primary charger.

FIG. 6 is a flowchart showing a sequence at the time of high pressure leak detection.

[Explanation of symbols]

 213 High voltage unit 401 Primary charging protection circuit 402 Primary charger cleaning motor 403 Control unit 502 Wire cleaning unit

Claims (2)

[Claims] 1. A charging device comprising: a charging wire; a primary charging unit having a voltage supply unit for supplying a voltage to the charging wire; and a photoconductor which can be charged by the primary charging unit. And an image forming apparatus that forms a toner image by performing development and transfers the toner image to a transfer material to form an image. A wire cleaning unit that can clean the charging wire, and a voltage supply unit that supplies a voltage. Sometimes, a leak detection unit that detects a leak in the primary charging unit and outputs a detection signal, and a voltage supply control unit that temporarily suspends and restarts voltage supply by the voltage supply unit based on a detection signal from the leak detection unit. An image forming apparatus comprising: a cleaning drive control unit that drives the wire cleaning unit when the voltage supply by the voltage supply unit is temporarily stopped. Location. 2. A voltage stop control unit for stopping supply of voltage by the voltage supply unit based on a detection signal by the leak detection unit after restarting supply of voltage by the voltage supply unit, An error message output means for outputting an error message together with the stop of the voltage supply;
The image forming apparatus according to claim 1, further comprising: