JPH01319772A - Transfer sheet peeling device - Google Patents

Abstract

PURPOSE:To prevent the increase of operation frequency of a separation claw and the scratch of a photosensitive body by adjusting a voltage impressing a separating charger according to the operation frequency of the peeling claw. CONSTITUTION:When a transfer sheet (a) is fed by resist rollers 13 and 14, a leading edge detecting sensor S1 is turned on the start a timer. When a peeling detecting sensor S0 is not turned on until the time A counts up, the device judges that the transfer sheet (a) is likely to wind itself around a photosensitive drum, and stops the timer A, drives a solenoid SOL to abut the separation claw 9 on the outer periphery of the photosensitive drum 1, and mechanically peels the transfer sheet. Every time the peeling claw 9 is driven, the value of the counter A is incremented by one. When the transfer sheet (a) is electrostatically peeled off by the peeling charger 7 or mechanically peeled off by the peeling claw 9, its leading edge is detected by a transfer sheet transmissive sensor S; moreover, every time the process is performed, the value of a counter B is incremented by one. When the operating frequency of the peeling claw 9 is more than 50% of the number of sheets separated, an applied voltage is boosted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for peeling transfer paper from a photoreceptor in a copying machine, a laser beam printer 2 facsimile, and other image forming apparatuses using a photoreceptor. It is.

[Prior art]

As an image forming apparatus having a transfer paper peeling device as described above, for example, an electrophotographic copying machine disclosed in Japanese Utility Model Application Publication No. 158458/1983 is known.

In this conventional electrophotographic copying machine, a peeling charger is provided on the downstream side of the transfer section between the photoreceptor and the transfer charger in the transfer paper conveyance direction, for electrostatically peeling off the transfer paper adhering to the surface of the photoreceptor. ing.

If the separation of the transfer paper by such a separation charger is not successful, the transfer paper will wind around the surface of the photoreceptor. To prevent this, it is operated intermittently on the downstream side of the photoreceptor rotation direction than the peeling charger! II release claw is provided.

If the peeling claw is in constant contact with the photoreceptor, the surface of the photoreceptor will be scratched, causing a problem that the image will become smeared. Therefore, in the conventional electrophotographic copying machine described above, a peeling detection means for detecting whether or not the transfer paper has peeled off from the photoreceptor is provided downstream of the peeling charger in the transfer paper IR feeding direction. Then, the peeling claw is activated only when the transfer paper is not peeled off.

[Problem to be solved by the invention]

As described above, whether or not the transfer paper is peeled off from the photoreceptor by the peel charger depends mainly on the change in the state of static electricity between the photoreceptor and the transfer paper depending on the atmosphere surrounding the photoreceptor. Therefore, once the J-regular peeling errors begin to occur, they tend to occur continuously, resulting in the peeling claw being operated frequently. For this reason, the above-mentioned conventional electrostatographic copying machine has the disadvantage that damage to the photoreceptor cannot be significantly prevented.

Therefore, an object of the present invention is to adjust the voltage applied to the stripping charger according to the frequency of operation of the stripping claw so that the frequency of operation of the stripping claw does not become too high, thereby preventing damage to the photoreceptor. It is something that I try to do.

Further, in the present invention, an upper limit is set on the voltage applied to the peeling charger, thereby eliminating the inconvenience of disturbing the transferred image.

[Means to solve the problem]

In order to achieve the above object, the transfer paper peeling device according to the present invention is provided with a
A peeling charger for peeling the transfer paper from the surface of the photoreceptor is provided, and a peeling claw that is intermittently operated is provided along the photoreceptor on the downstream side of the peeling charger in the rotational direction of the photoreceptor. Further, a peeling detection means for detecting peeling of the transfer paper from the photoreceptor is provided downstream of the peeling charger in the transfer paper conveyance direction, and when the peeling detection means detects a peeling error of the transfer paper, the peeling claw is activated. The transfer paper peeling device is characterized in that the voltage applied to the peeling charger is adjusted in accordance with the operating rate of the peeling claw per number of copies processed.

C Effect] When copy processing is performed, the number of processed copies is counted. At the same time, the number of activations of the peeling claw is also counted, and the operating rate of the peeling claw is determined by the ratio of the zero count amount. When this operating rate becomes higher than a predetermined value, the voltage applied to the peeling charger is increased and the transfer The paper is electrostatically peeled off, reducing the operating rate of the peeling claw. Furthermore, if the operating rate becomes too low, the voltage applied to the peel charger is reduced. As a result, the operating rate of the peeling claw is adjusted to an appropriate range.

〔Example〕

Next, embodiments embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. here the first
FIG. 2 is a block diagram showing the electrical system of the paper stripping device 5, and FIG. 3 is a flowchart showing the processing procedure of the ff1ll separation device. It is.

The following examples are merely specific examples of the present invention, and are not intended to limit the technical scope of the present invention.

First, with reference to FIGS. 1 and 2, the hardware configuration of a transfer paper peeling device 3 according to an embodiment of the present invention will be described.

In FIG. 1, reference numeral 1 denotes a photosensitive drum having a photosensitive member formed on its outer peripheral surface, and rotates in the direction of arrow R. As shown in FIG.

Around the photosensitive drum 1 is the main charger 2° developing device! 4. Transfer charger5. Peeling charger 7, peeling claw 9. Cleaning units 8 are provided in this order. The peeling claw 9 is rotationally driven by a claw driving solenoid SQL.

The photosensitive drum 1 to which a predetermined potential is applied by the main charger 2 rotates in the direction shown by arrow R, and when the photosensitive member on the outer peripheral surface is irradiated with reflected light from an original (not shown), an original image is formed on the surface of the photosensitive member. A corresponding electrostatic latent image is formed which is developed into a toner image as it passes near the developer device 4.

This toner image is generated by the voltage applied by the transfer charger 5 when the transfer IF,a sent out in the direction shown by the arrow Y by the registration rollers 13 and 14 passes through the transfer section between the photosensitive drum 1 and the transfer charger 5. The image is transferred to the transfer paper a side.

As described above, the peeling charger 7 is provided downstream of the transfer charger 5, and the applied voltage peels off the transfer fiEa electrostatically attracted to the photoreceptor of the photosensitive drum l. The peeled transfer paper a is further conveyed by the conveyor belt 6 to a fixing roller (not shown) on the downstream side, and the toner image is fixed thereon.

A leading edge detection sensor S is provided near the exits of the registration rollers 13 and 14 to detect passage of the leading edge of the transfer paper a.

Furthermore, a peeling detection sensor (an example of peeling detecting means) So is provided downstream of the peeling charger 7 in the transfer paper conveying direction for detecting peeling of the transfer paper a from the photoreceptor.

Further, at a position downstream of the peeling detection sensor S0 in the transfer paper conveyance direction and set at a distance from the leading edge detection sensor S1 to be slightly longer than the length of the transfer paper in the conveyance direction, a transfer paper passage detection sensor is provided. A sensor S2 is provided.

The tip detection sensor S1. The peeling detection sensor S0 and the transfer paper passage detection sensor S are each connected to the central processing unit CPU of the microcomputer via an input interface circuit 15, as shown in FIG. C.P.
The output boat U includes a voltage control circuit 17 for controlling the voltage applied to the peeling charger 7 via an output interface circuit 16, and a solenoid S for driving the peeling claw 9.
An amplifier 18 that drives the OL is connected.

The above-mentioned microcomputer has a tip detection sensor S1
．． Peeling detection sensor S0. Receives each on/off signal from the transfer paper passage detection sensor S2, performs logical judgment according to the flowchart shown in No. 3 UyJ, and outputs the solenoid SQ.
At the same time as driving L, the voltage applied to the peeling charger 7 is controlled.

The processing procedure will be explained below.

In addition, in the following explanation, 31. S2. ... represents the number of the processing procedure (step).

In FIG. 1, first, it is determined whether copy processing is currently in progress (S1). If the copying process is in progress, it is determined whether the leading edge detection sensor Sl has changed from the off state to the on state, that is, whether the leading edge of the transfer paper a has reached the position of the leading edge detection sensor Sl.

Registration roller 13. When the transfer paper a is fed in by +4, the above tip l1lli! Since the detection sensor S is turned on, the process proceeds to S3 and a timer A is started. The timer A is a timer set to a time slightly longer than the time it takes for the transfer paper a to reach the peeling detection sensor S0 from the leading edge detection sensor S1. Therefore, if the peeling detection sensor S0 is not turned on before the timer A counts up, it can be determined that the transfer paper a is winding around the photosensitive drum l, and the peeling claw 9 is activated to remove the transfer paper a. It is necessary to peel it off.

Following the process in S3, it is determined in S4 whether the transfer paper passage detection sensor S2 has changed from on to off, that is, whether the transfer paper a has finished passing through the transfer area around the photoreceptor. , a are being supplied to the transfer unit, the determination in S4 is always NO, and the process is continued in Sl.
Return to

In a state where the leading edge of the transfer paper a is being fed out by the registration rollers 13 and 14, the determination in S2 is NO, and if the timer A is operating (S5), the peel-off sensor S0 is switched from OFF to ON. If the peeling detection sensor S0 turns on from off, it means that the transfer paper has been peeled off from the photosensitive drum 1, and the timer A is stopped (S7). If not, it is determined whether a predetermined waiting time set by timer A has elapsed (S8). Here, if the predetermined waiting time has not yet elapsed, the process jumps to S4.

When it is determined that the waiting time has elapsed, it is determined that the transfer paper a is winding around the photosensitive drum 1 and the timer A is stopped, and the solenoid SQL is driven to move the peeling claw 9 around the outer circumference of the photosensitive drum 1. The transfer paper a is mechanically peeled off by bringing it into contact with the surface (S9).

When the peeling claw 9 is driven once in this manner, 1 is added to the value of the counter A (SIO). When the transfer paper is electrostatically peeled off by the peeling charger 7 or mechanically peeled off by the peeling claw 9, its leading edge will eventually pass the position of the transfer paper passage detection sensor S2, and the judgment in step S4 will be made. becomes a yes. Transfer paper a like this
When it passes through the transfer area, it is determined that the copying process for one sheet of transfer paper has been completed, and 1 is added to the value of counter B in Sll. That is, counter A is a counter for the number of times the peeling claw is activated, whereas counter B is a counter for the number of copies processed.

Next, in step 512, it is determined whether the value of counter B has reached 10, and when the number of processed sheets reaches 10, the value of counter A, Uchi, and the number of times the peeling claw is operated out of 10 copy processes are determined. is 5 times or more (313), and if the peeling claw has been driven more than 5 times, it is determined whether the voltage applied to the peeling charger 7 is already at the upper limit value (514), and the If the upper limit value has not been reached, the applied voltage is increased by one step (S15), and the values of counters A and B are cleared to zero.

If the voltage applied to the peel charger 7 is increased too much,
Even if the transfer paper a is successfully peeled off from the photosensitive drum 1, the toner image formed on the transfer paper a is also affected by static electricity, resulting in disturbance of the toner image.

Therefore, in step 314, it is checked whether the applied voltage has already reached a predetermined upper limit value, and if it has reached the upper limit value, the process proceeds to S16 without increasing the applied voltage any further.

Then, the counters A and B are cleared, and the process returns to step 31.

Further, in 313, if the value of counter A is determined to be 5 or less, it is determined whether the value is less than 3 (517), and if it is less than 3, the applied voltage has already reached the lower limit value. It is determined whether the value is decreasing (318). Normally, the lower limit value in this case is almost equal to 0, and if it is determined that the lower limit value has been reached, the applied voltage cannot be lowered any further, so the process is carried out by the counter A at 516. , B to clear processing. Further, if the lower limit value has not been reached in 818, the applied voltage is lowered by one step and the process moves to S26.

In this embodiment, the case where the number of times the separation claw 9 operates is 3 or more and 5 or less out of 10 copies processed is considered appropriate. Therefore, if it is determined in S17 that the value of counter A is 3 or more, the counters A and B are cleared in S16 without changing the applied voltage.

In this way, each time the copying process is performed for 10 sheets, it is determined how many times the peeling claw 9 has been activated, and if the number of activations is 5 or more, the applied voltage is increased and the peeling charger 7 performs electrostatic peeling. If the number of times is 3 or more and less than 5 times, the applied voltage is considered to be appropriate and the same value is maintained, and if the number of times is less than 3 times, the applied voltage is further reduced.

In the above embodiment, the proper operating rate of the peeling claw 9 is 5/10 to 3.
/10, but such a value is adjusted as appropriate at the time of shipment of the machine or by the user.

〔Effect of the invention〕

As described above, in the present invention, a peeling charger for peeling the transfer paper from the surface of the photoreceptor is provided on the downstream side in the transfer paper feeding direction from a transfer section near the photoreceptor, and the peeling charger is provided along the photoreceptor. A peeling claw that is intermittently operated is provided downstream from the charger in the direction of rotation of the photoreceptor, and furthermore, a peeling claw is provided downstream from the peeling charger in the transfer paper conveyance direction to detect peeling of the transfer paper from the photoreceptor. In the transfer paper peeling device, the peeling claw is actuated when the peeling detecting means detects a peeling error of the transfer paper, and the peeling claw is operated according to the operating rate of the peeling claw during the number of copying processes. This transfer paper peeling device is characterized by adjusting the voltage applied to the charger, so it can be used when the transfer paper tends to wrap around the photosensitive drum for a long time due to changes in the external fa environment such as temperature and humidity. Also, damage to the photoreceptor can be suppressed to a minimum while preventing mistakes in peeling off the transfer paper by appropriately adjusting the operating rate of the peeling claw.

[Brief explanation of the drawing]

FIG. 1 is a schematic side sectional view of a transfer paper peeling device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the electrical system of the same peeling device, and No. 3121 is a flowchart showing the processing procedure of the same peeling device. be. [Explanation of symbols] l...Photosensitive drum 7...Peeling charger 9...Peeling claw So...Peeling detection sensor (peeling detection means) S,...
Leading edge detection sensor S...transfer paper passage detection sensor.

Claims (2)

[Claims] (1) A peeling charger for peeling the transfer paper from the surface of the photoreceptor is provided downstream from the transfer section near the photoreceptor in the direction of transfer paper conveyance, and along the photoreceptor, downstream from the peeling charger in the direction of rotation of the photoreceptor. A peeling claw that is operated intermittently is provided on the side, and further, a peeling detection means for detecting peeling of the transfer paper from the photoreceptor is provided downstream of the peeling charger in the transfer paper transport direction, and the peeling detection means In the transfer paper peeling device which operates the peeling claw when a peeling error of the transfer paper is detected, the voltage applied to the peeling charger is adjusted according to the operating rate of the peeling claw per number of copies processed. A transfer paper peeling device characterized by: (2) The stripping device according to claim (1), wherein the voltage applied to the stripping charger is adjusted within a predetermined upper limit.