JPH0651584A - Power source abnormality countermeasure device for electrostatic recorder - Google Patents

Abstract

PURPOSE:To reduce the stop of the recording action of an abnormal time according to the function of a high-voltage power source as much, as possible. CONSTITUTION:As for the respective high-voltage power sources 31, 32, 33 and 35 for an electrostatic charger 12, a developing device 14 and a transfer electrode 19, their own power sources are turned off at the abnormal electric discharge time thereof. Simultaneously, the recording action is stopped by a CPU 40. As for the high-voltage power source 34 for a paper electro static charging roller 20 and a cleaning roller 23 and the high-voltage power source 35 for a destaticizer 26, their own power sources are turned off at the abnormal electric discharge time thereof. However, since a recording image does not receive the effect thereof, the recording action is not stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply abnormality countermeasure device for an electrostatic recording device using an electrophotographic process such as a page printer, an analog copying machine and a digital copying machine.

[0002]

2. Description of the Related Art In an electrostatic recording apparatus such as a page printer (laser beam printer), a peripheral surface of a photosensitive drum, which is an image bearing member, is uniformly charged by a charger and then a laser is applied to the peripheral surface of the photosensitive drum. Image exposure is performed with a beam to form an electrostatic latent image. This latent image is developed and visualized by a developing device to become a toner image. The toner image formed on the peripheral surface of the photoconductor drum is transferred onto recording paper fed at the same timing. Then, the recording paper on which the toner image has been transferred is separated from the photosensitive drum,
After the toner image is conveyed to the fixing unit and the toner image is fixed, the toner image is discharged to the outside of the apparatus.

By the way, in such an electrostatic recording apparatus, a high voltage power source (1.5 KV or more) is used for charging, developing, transferring and the like. In this case, a high voltage of 5 to 10 KV is used for charging and transfer, and a high voltage of about 3 KV is used for development. In addition, a high voltage power supply of about 2 KV is used to charge or charge the leading edge of the paper in order to improve the paper separation performance. Further, high pressure may be applied to improve the cleaning performance.

However, when the machine is used for a long time in the high voltage power source, sufficient creepage distance and space distance cannot be maintained in the high voltage power supply path or the electrode portion, which may cause leakage (spark discharge). Toner burns when leaking. Therefore, recently, for safety, each high-voltage power supply is equipped with an abnormal discharge detection circuit that detects an abnormal discharge with an increase in output current, and when an abnormal discharge occurs, the power is turned off and the high-voltage output is stopped. There is. Further, the machine itself is stopped by the signal from the abnormal discharge detection circuit to stop the printing operation.

[0005]

However, in this way, the portion which does not directly affect the recorded image,
For example, even if the high-voltage power supply used for paper separation or the high-voltage power supply used for cleaning is turned off, the printing operation is prohibited. Had to be turned off / on to restore the main power of the machine, which was not convenient.

In view of the above problems, the present invention devises a countermeasure against an abnormality according to the function of each high-voltage power source, thereby reducing the stop of the recording operation due to the abnormality of the high-voltage power source as much as possible. It is an object of the present invention to provide a power supply abnormality countermeasure device for an electrostatic recording device.

[0007]

Therefore, according to the present invention, an image bearing member is charged, imagewise exposed, and developed to form a toner image, which is transferred to a recording paper, fixed and recorded. An electrostatic recording device comprising a plurality of high-voltage power supplies, and an abnormal discharge detection circuit that detects an abnormal discharge for each high-voltage power supply and turns off the power supply by itself, wherein the plurality of high-voltage power supplies are used for toner image formation and The first group of high voltage power supplies used for transfer and the other second group of high voltage power supplies are divided, and the recording operation is stopped at the time of detecting abnormal discharge by each abnormal discharge detection circuit of the first group of high voltage power supplies, A power supply abnormality countermeasure device is configured by providing an abnormality processing unit that does not stop the recording operation when an abnormal discharge is detected by each abnormal discharge detection circuit of the high voltage power supplies of the second group.

[0008]

In the above structure, when an abnormality occurs in any of the high voltage power supplies of the first group used for toner image formation and transfer, the power is turned off and the recording operation is stopped. If an abnormality occurs in any of the high voltage power supplies of the second group that does not affect the recorded image, the power is turned off, but the recording operation is not stopped,
This improves running performance.

[0009]

EXAMPLE An example of the present invention will be described below. First, the overall configuration of the electrostatic recording device will be described with reference to FIG. The photoconductor drum 10, which is an image carrier, is formed by applying an OPC photoconductive layer that receives light and conducts electricity onto the drum, and is driven to rotate clockwise in the drawing.

The photoconductor drum 10 includes a scorotron charger.
12 provides a uniform charge by corona discharge. After the uniform charging, the image exposure unit 13 performs image exposure of the first color on the photosensitive drum 10 based on the image signal. The image exposure means 13 uses a laser diode (not shown) as a light emitting source, and performs main scanning with a rotating polygon mirror 13a, fθ lens 13b, reflection mirror 13c, etc. A latent image is formed on the drum 10. Here, for example, the image portion is exposed to form a reverse latent image in which the image portion has a low potential.

After image exposure, the photosensitive drum 10 is developed for the first color. That is, four developing devices each containing a developer consisting of yellow (Y), magenta (M), cyan (C), and black (K) toner and a carrier.
14 is provided, and by one of them, the development of the first color is performed by the developing sleeve 14a which contains a magnet and holds the developer and rotates. A bias voltage is applied between the developing sleeve 14a and the photosensitive drum 10 in the developing area, whereby the toner is released from the carrier,
The image is visualized (reversal development) by adhering to the low potential portion of the photoconductor drum 10.

After the formation of the toner image of the first color, the second color toner image forming step is started at the second rotation of the photosensitive drum 10, and uniform charging is performed again by the charger 12 to obtain the image data of the second color. After the latent image is formed by the image exposing means 13, the development by the second color is visualized. Third color, 4
As for the second color, the toner image formation similar to that of the second color is performed, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

On the other hand, the recording paper P fed from the paper feed cassette 15 by the paper feed mechanism 16 is sent to the nip portion (transfer area) 18 formed by the photosensitive drum 10 and the transfer belt 17,
Transfer belt 17 Transfer electrode 19 using a corona discharger from the back side
A transfer electric field is applied by this, and a multicolor image is transferred onto the recording paper P. Here, the holding roller 2 that stretches the transfer belt 17
A voltage is applied to the shaft of the upstream side holding roller 20 of 0 and 21, and the recording paper P is placed between the transfer belt 17 wound around the holding roller 20 and the brush 22 which is grounded. When entering, electric charges are injected into the recording paper P, and an attractive force is generated between the recording paper P and the transfer belt 17.

In the vicinity of the downstream side holding roller 21, a recording sheet P is separated from the transfer belt 17 by a static eliminator 26, which will be described later, to remove electricity by corona discharge using the shaft of the downstream side holding roller 21 as a counter electrode. In addition, the recording paper P of the transfer belt 17
A cleaning roller 23 to which a voltage is applied is provided in the return path after separation, and removes the toner attached to the transfer belt 17. Specifically, as shown in FIG. 3, the toner moves to the cleaning roller 23, and this is the cleaning blade.
It is scraped off by 23a and collected.

The transfer belt 17 is rotated clockwise about the shaft of the downstream side holding roller 21 and is separated from the photosensitive drum 10 during the formation of a multicolor image. The recording paper P holding the multicolor image separated from the transfer belt 17 is conveyed between a fixing heater roller 24 having a heater 24a therein and a fixing pressure roller 25 which is in pressure contact with the fixing heater roller 24. By applying heat and pressure between 25, the adhered toner is melted, fixed on the recording paper P, and then discharged to the outside of the apparatus.

After the transfer, the residual toner remaining on the peripheral surface of the photosensitive drum 10 is discharged by a static eliminator 26 using a corona discharger, and then reaches a cleaning blade 27 where it is scraped and collected. It Here, the static eliminator 26 also serves as static eliminator for the recording paper P depending on its arrangement. During the formation of the multicolor image, the charge removal by the charge remover 26 is kept in the OFF state, and the cleaning blade 27 is kept in a state of being separated from the photosensitive drum 10.

Here, as shown in FIG.
12, high voltage power supply 31 for developing device 14 and transfer electrode 19
~ 33 are used. A common high-voltage power supply 34 is used for the upstream holding roller (hereinafter, referred to as a paper charging roller) 20 of the transfer belt 17 and the cleaning roller 23. Further, a high voltage power supply 35 is used for the static eliminator 26.

The high-voltage power supplies 31 to 35 are ON / OFF controlled by a high-voltage remote signal (CONT) output from the CPU 40 via an I / O driver (not shown), and detect abnormal discharge (spark discharge). It also has an abnormal discharge detection circuit that turns itself off. Further, an abnormality detection signal (NG) from each abnormal discharge detection circuit is sent to the CPU 40. The abnormal discharge detection circuit detects abnormal discharge when the output current increases.

This will be described with reference to FIG. 3 as an example of the transfer unit portion. The high voltage power supply 33 for the transfer electrode 19 is 6.5 KV
When the abnormal discharge detection circuit 33a detects an abnormal discharge, the high voltage remote signal (CONT) is turned off.
It is set to FF to prohibit high voltage output.
Then, the abnormality detection signal (NG) is sent to the CPU 40.

Paper charging roller 20 and cleaning roller 23
The high-voltage power supply 34 for use has a relatively low voltage of, for example, 2 KV,
When the abnormal discharge detection circuit 34a detects an abnormal discharge, the high voltage remote signal (CONT) is turned off to prohibit the high voltage output. Then, the abnormality detection signal (NG) is sent to the CPU 40. CP
In U40, various processing is performed by receiving an abnormality detection signal from the abnormal discharge detection circuit of each high-voltage power supply 31-35. The high-voltage power supply 31-35 is used for toner image formation and transfer.
The high-voltage power sources of the group and the high-voltage power sources of the second group other than the group are separately processed.

Regarding the processing contents of the CPU 40, FIG. 4 and FIG.
The flowchart will be described. FIG. 4 is a flowchart of a high-voltage abnormality detection processing routine, which corresponds to abnormality processing means according to the present invention. In step 1 (denoted as S1 in the drawing, the same applies hereinafter), the presence or absence of an abnormality detection signal of the high-voltage power supply 31 for the charger 12 is detected. High voltage power supply for charger 12
Reference numeral 31 is used for forming a toner image and corresponds to a high voltage power source of the first group. Therefore, if there is an abnormality detection signal, the process proceeds to step 6.

In step 2, the high voltage power supply 32 for the developing device 14
The presence or absence of the abnormality detection signal of is detected. The high-voltage power supply 32 for the developing device 14 is used for toner image formation and corresponds to the high-voltage power supply of the first group. Therefore, if there is an abnormality detection signal, the process proceeds to step 6. In step 3, the transfer electrode
The presence or absence of an abnormality detection signal of the high voltage power supply 33 for 19 is detected. The high voltage power supply 33 for the transfer electrode 19 is used for transferring the toner image and corresponds to the high voltage power supply of the first group. Therefore, if there is an abnormality detection signal, the process proceeds to step 6.

In step 4, the presence / absence of an abnormality detection signal of the high voltage power source 34 for the paper charging roller 20 and the cleaning roller 23 is detected. Paper charging roller 20 and cleaning roller 23
The high-voltage power source 34 for use in is not used for toner image formation and transfer and does not affect the recorded image, and therefore corresponds to the high-voltage power source of the second group. Therefore, if there is an abnormality detection signal, the process proceeds to step 8.

In step 5, the high voltage power supply 35 for the static eliminator 26
The presence or absence of the abnormal signal of is detected. High voltage power supply 35 for static eliminator 26
Is not used for toner image formation and transfer,
Since it does not affect the recorded image, it corresponds to the high voltage power supply of the second group. Therefore, if there is an abnormality detection signal, the process proceeds to step 9. In this way, when the high-voltage power supply of the first group is abnormal, the routine proceeds to step 6, the abnormal high-voltage state is displayed, the recording (printing) operation is stopped at the next step 7, and this routine is ended.

Therefore, for example, a high voltage power supply 33 for the transfer electrode 19
If an abnormal discharge occurs at, the abnormal discharge detection circuit 33
The high voltage remote signal (CONT) is turned off by a, the high voltage output is prohibited, and the recording operation is stopped by the CPU 40. In order to cancel this state, it is necessary to turn off / on the main power source of the device. The same applies to the high voltage power supply 31 for the charger 12 and the high voltage power supply 32 for the developing device 14.

On the other hand, when the high voltage power source of the second group is abnormal, the process proceeds to step 8 or step 9 and only the error flag F1 or the error flag F3 is set, without stopping the recording operation. This routine ends. Therefore, the paper charging roller 20 and the cleaning roller
If an abnormal discharge is generated in the high voltage power supply 34 for 23, the abnormal discharge detection circuit 34a will detect the high voltage remote signal (CON
Although T) is turned off and high-voltage output is prohibited and the paper charging and cleaning functions are lost, the CPU 40 does not stop the recording operation and printing is possible.

However, the processing by the second processing routine of FIG. 5 is performed (because the error flag F1 is set in step 8 of FIG. 4). In step 11, it is determined whether or not the error operation flag F2 is set, and if NO, the process proceeds to step 12. In step 12, the error flag F1
Is set, and if NO, the process proceeds to step 13.

Therefore, if normal, proceed to step 13,
During one print, it is determined whether or not the high-voltage power supply 34 has an abnormality. If NO, it is as it is, and if YES, the step.
The error counter C is reset at 14 and this routine is finished. If there is an abnormality, that is, if the high-voltage power supply 34 has an abnormality and the error flag F1 is set by the routine of FIG. 4, the determination in step 12 is YES, and therefore, the processing proceeds to step 15 and thereafter.

In step 15, a timer is started in order to measure the elapsed time from the occurrence of abnormality. In the next step 16, the error counter C is incremented. In the next step 17, the error operation flag F2 is set. In the next step 18, the error flag F1 is reset. In the next step 19, it is judged whether or not the error counter C has reached a predetermined value (for example, 150). At first, since it does not reach the predetermined value, this routine is ended.

In the next and subsequent routines, since the error operation flag F2 is set, the process proceeds from step 11 to step 20. In step 20, it is determined whether or not the timer has reached a predetermined value (for example, 6 seconds), this routine is ended until 6 seconds have elapsed, and when 6 seconds have elapsed, the routine proceeds to step 21 and the subsequent steps.

In step 21, the high voltage remote signal (CONT) to the high voltage power source 34 is turned off / on, and the high voltage power source 34 turned off by the abnormal discharge detection circuit 34a is turned on.
Return to N state. Then, in the next step 21, the error operation flag F2 is reset. In this way
Even if an abnormality occurs in the high-voltage power supply 34 and the abnormal discharge detection circuit 34a turns off the power supply itself, it automatically turns off after 6 seconds.
Return to N state.

However, it is dangerous if the abnormal state continues even after the recovery, so when the error counter C reaches a predetermined value (for example, 150) in the judgment at step 19, the routine proceeds to step 23 to display the abnormal high voltage state. Then, in the next step 24, the recording operation is stopped. In order to cancel this state, it is necessary to turn off / on the main power source of the device. When an abnormal discharge occurs in the high voltage power supply 35 for the static eliminator 26, the abnormal discharge detection circuit turns off the high voltage remote signal (CONT).
However, although the high-voltage output is prohibited and the static elimination function is lost, the CPU 40 does not stop the recording operation and printing is possible.

However, the processing by the third processing routine of FIG. 6 is performed (because the error flag F3 is set in step 9 of FIG. 4). In step 31, it is determined whether or not the error operation flag F4 is set, and if NO, the process proceeds to step 32. In step 32, the error flag F3
Is set, and if NO, the process proceeds to step 33.

Therefore, if normal, go to step 33
During one print, it is determined whether or not the high-voltage power supply 35 is normal. If NO, then it is as it is, and if YES, then step.
At 34, the error counter D is reset and this routine ends. If there is an abnormality, that is, if the high-voltage power supply 35 has an abnormality and the error flag F3 is set by the routine of FIG. 4, the determination at step 32 is YES, and therefore the processing proceeds to step 35 and thereafter.

In step 35, a timer is started in order to measure the elapsed time from the occurrence of abnormality. In the next step 36, the error counter D is incremented. In the next step 37, the error operation flag F4 is set. In the next step 38, the error flag F3 is reset. In the next step 39, it is judged whether or not the error counter D has reached a predetermined value (for example, 150). At first, since it does not reach the initial value, this routine is ended.

In the next and subsequent routines, the error operation flag F4 is set, so the routine proceeds from step 31 to step 40. In step 40, it is determined whether or not the timer has reached a predetermined value (for example, 6 seconds), this routine is ended until 6 seconds have elapsed, and when 6 seconds have elapsed, the routine proceeds to step 41 and thereafter.

In step 41, the high voltage remote signal (CONT) to the high voltage power supply 35 is turned off / on, and the high voltage power supply 35 turned off by the abnormal discharge detection circuit is returned to the on state. Then, in the next step 41, the error operation flag F4 is reset. In this way, even if an abnormality occurs in the high-voltage power supply 35 and the abnormal discharge detection circuit turns off the power supply itself, it automatically returns to the ON state after 6 seconds.

However, since it is dangerous if the abnormal condition continues even after the recovery, when the error counter D reaches a predetermined value (for example, 150) in the judgment at step 39, the routine proceeds to step 43 to display the abnormal high voltage condition. Then, in the next step 44, the recording operation is stopped. In order to cancel this state, it is necessary to turn off / on the main power source of the device.

[0039]

As described above, according to the present invention, a plurality of high voltage power supplies are used for toner image formation and transfer.
The high voltage power supply of the group and the high voltage power supply of the second group other than that are divided, and the recording operation is stopped when the high voltage power supply of the first group is abnormal, but stopped when the high voltage power supply of the second group is abnormal. Since it is not performed, it is possible to print when it does not directly affect the recorded image, it is possible to reduce the stop of recording operation due to abnormality of the high voltage power supply without impairing safety, and improve running performance. The effect is obtained.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electrostatic recording device showing an embodiment of the present invention.

[Fig. 2] Layout of high-voltage power supply

FIG. 3 is a layout diagram of a high-voltage power supply in the transfer unit section.

FIG. 4 is a flowchart of a high voltage abnormality detection processing routine.

FIG. 5 is a flowchart of a second processing routine.

FIG. 6 is a flowchart of a third processing routine.

[Explanation of symbols]

 10 Photosensitive drum 12 Charging device 13 Image exposure means 14 Developing device 17 Transfer belt 19 Transfer electrode 20 Paper charging roller 23 Cleaning roller 26 Static eliminator 31 to 35 High voltage power supply 33a, 34a Abnormal discharge detection circuit 40 CPU

Claims (1)

[Claims] 1. An image carrier is charged, imagewise exposed and developed,
An electrostatic recording device for forming a toner image, transferring the toner image onto a recording paper, fixing and recording the image, comprising a plurality of high-voltage power supplies,
In a device provided with an abnormal discharge detection circuit that detects an abnormal discharge for each high-voltage power supply and turns off the power supply itself, a plurality of high-voltage power supplies are used for toner image formation and transfer. When the abnormal discharge detection circuits of the first group of high voltage power supplies detect abnormal discharge, the recording operation is stopped and the abnormal discharge detection circuits of the second group of high voltage power supplies are detected. A power supply abnormality countermeasure device for an electrostatic recording device, which is provided with an abnormality processing unit that does not stop a recording operation when a discharge is detected.