JPS6227390B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic apparatus, and more particularly to a program control method for compensating for fatigue of a photoreceptor thereof.

Generally, as the number of times the photoreceptor in a transfer type electrophotographic apparatus is used increases, its characteristics change due to a so-called photoreceptor fatigue phenomenon.

One way to compensate for the negative effects of this fatigue on the quality of copied images is to change the charge amount, exposure amount, developing bias potential, etc. However, in order to avoid the trouble of manually operating each time, a program control method is used. has already been proposed. That is, as shown in FIG. 1, the control operation of the program control device 1, which is programmed to predict the fatigue of the photoreceptor, is advanced based on the detection output of the copy number detection device 2 that detects the number of copies used, and the charging The amount adjusting device 3, the exposure amount adjusting device 4, and the developing bias potential adjusting device 5 were each controlled to change the amount of charge, the amount of exposure, and the developing bias potential during copying by appropriate amounts. However, the causes of fatigue and the resulting changes in properties are complex, and simple control based only on the number of copies cannot be expected to be sufficiently effective, so it has not been put into practical use.

It is an object of the present invention to solve these problems and to perform photoreceptor fatigue program control more accurately. In other words, the exposure amount, which is one of the major causes of fatigue, varies depending on the type of original to be copied and the exposure adjustment status during operation, and the fatigue characteristics of the photoreceptor deviate from predictions. As it turned out that no compensation had been made,
The control accuracy is improved by detecting the amount of exposure applied to the photoreceptor during use of the electrophotographic apparatus and correcting the progress of program control based on the detected value.

The present invention will be explained below with reference to the accompanying drawings. 2 and 3 are block diagrams showing different embodiments of the present invention, and the same parts as in FIG. 1 are given the same reference numerals and their explanation will be omitted. In FIG. 2, 6 is a program control device 1.
This is a program step progress control device for controlling the progress of a control program according to the present invention, and operates in accordance with the detection value of an exposure amount detection device 7 that detects the exposure amount during copying. The program control device 1 is programmed to predict the fatigue characteristics of the photoreceptor used with respect to the number of copies and change the amount of charge, amount of exposure, developing bias potential, etc. to compensate for the adverse effects of fatigue on the quality of copied images. The program is advanced by the detection output issued every time the number of copies is counted from the copy number detection device 2, and the charge amount adjustment device 3, the exposure amount adjustment device 4, and the developing bias potential adjustment device 5 each perform the program in advance. according to the established program,
The amount of charge, amount of exposure, development bias potential, etc. are controlled to predicted compensation values. At the same time, the exposure amount detection device 7
The detected value is supplied to the program step progress control device 6, and the degree of progress of the fatigue correction program by the program control device 1 is corrected in accordance with the detected value.

By controlling in this way, the influence of fatigue caused by the exposure dose, which causes the greatest variation in fatigue characteristics, is compensated for, and a good quality copy image is always ensured.

In the embodiment shown in FIG. 3, since the influence of the exposure amount on the fatigue of the photoreceptor varies depending on the use condition of the photoreceptor, that is, the number of copies, the total number of copies is determined in conjunction with the detection value of the exposure amount detection device 7. The count value of the total number of copies is supplied from the detection device 2 to the program step progress control device 6, and the progress of the control program by the program control device 1 is controlled so that fatigue compensation can be performed in accordance with the fatigue of the photoreceptor at that time. charge amount adjustment device 3, exposure amount adjustment device 4
and a developing bias potential adjusting device 5. In this way, more accurate photoreceptor fatigue compensation can be performed.

4, 5 and 6 show more specific embodiments of the present invention, in which reference numeral 11 has a photoreceptor layer on its surface, and an original 13 illuminated by an illumination lamp 12. The original 13 is first charged by a charging device 15 on a photoreceptor drum that is exposed to reflected light through a lens 14, and then moved in the direction of arrow A.
A latent image is formed by exposure, and the latent image passes through a developing device 16 and is brought into contact with toner to be developed, and then is transferred by a transfer device 17. After the image is transferred onto the paper traveling in the direction of arrow C, the surface of the photoreceptor is cleaned by a cleaning device 18. Reference numeral 19 in FIG. 4 is arranged near the photosensitive drum 11, and the lens 14
This is a photoelectric conversion element that is provided to receive part of the projected light at a position adjacent to the irradiation surface of the photoreceptor onto which the reflected light from the original 13 is projected, and converts electricity according to the amount of exposure of the photoreceptor drum 11. It generates a signal and supplies it to the program step progression controller 6. Thereby, the program step progress control device 6 controls the DC voltage of the charging device 15, the power supply voltage or series resistance of the illumination lamp 12, and the developing The degree of progress of the program in the program control device 1, which controls the developing bias potential of the device 16 in accordance with the program step at that time, is corrected in accordance with the exposure amount. 20 in Figure 5
is an amplifier that subtracts the charging current, developing current, and transfer current from the current flowing through the photoreceptor drum 11, detects and amplifies the exposure current, and supplies this output to the program step progress control device 6 to control the exposure. The degree of progress of the control program by the program control device 1 is controlled according to the amount.

In addition, in general office copying, since the image area ratio of the document is almost constant, the setting value data of the exposure amount adjustment device 4 such as the diaphragm and illumination lamp power supply voltage adjustment device is changed as shown in FIG. By inputting the value to the program step progress control device 6, substantially the same effect can be obtained even if the value detected by the exposure amount detection device 7 is substituted.

In the above embodiments, program step progress control using electrical signals has been described, but program step progress control using a mechanical mechanism is also possible, and a specific example thereof is shown in FIG. In FIG. 7, 21 is a copy counter for counting the number of copies, to which is directly connected a swinging arm 22 that pivots back and forth in the direction of arrow D each time the number of copies is counted. 23 is rotatably supported by a shaft 24 and connected by a wire 26 to an aperture 25 that adjusts the exposure amount, and is operated left and right as shown by arrow E to adjust the irradiation area of the photoreceptor drum 11. It is a lever that increases or decreases the aperture. 27, the swinging motion of the swinging lever 22 is transmitted through the speed reduction mechanism 28, a drive lever 29 directly connected to its drive shaft, and an intermediate link 30;
The program wheel rotates in one direction only in small steps as shown by arrow F, and is provided with a resistance pattern 27a that predicts the fatigue characteristics of the photoreceptor drum 11 and corresponds thereto. 31 is amplifier 3
2. A developing bias potential control device composed of resistors 33, 34, power supplies 35, 36, and the like. The intermediate link 30 has one end 37 connected to the swinging lever 22 with a shaft 37.
A pin shaft 38 provided at the other end is pivotally supported by
is engaged with a long hole 39 provided in the drive lever 29, and furthermore, a long hole 40 provided in the middle is engaged with a pin shaft 41 provided at one end of the aperture lever 23. When the program wheel 27 is rotated step by step for each count of the copy counter 21, a resistance value that changes depending on the rotational position is taken out from the brush 27b provided in contact with the resistance pattern 27a, and the developing bias voltage is Resistor 33 of control device 31
and 34, the ratio at which the voltage of the power supply 35 is divided changes, and the input potential applied to the amplifier 32 changes. Therefore, the developing bias of the developing device 16 to which the output of the amplifier 32 is supplied changes. The potential is controlled as programmed. On the other hand, when the aperture lever 23 is operated, the aperture 25 is opened and closed, and the intermediate link 30 is moved up and down by the pin shaft 41 to change the engagement position of the pin shaft 38 with respect to the drive lever 29. The swing angle of the drive lever 29 changes with respect to the swing angle of the deceleration mechanism 28.
The incremental rotation angle of the program wheel 27 rotated via the aperture lever 23 is corrected by the operating position of the aperture lever 23. That is, when the aperture 25 is opened and the amount of exposure increases, the rotation angle of the program wheel 27 increases, and the developing bias potential of the developing device 16 is increased accordingly to cope with fatigue of the photoreceptor in the photoreceptor drum 11.

According to the present invention, as explained above, even when the fatigue of the photoreceptor varies greatly from the predicted characteristics depending on the exposure amount, an appropriate correction is always performed, and a copied image of constant image quality can be obtained. In addition, even in a copying machine equipped with a manual image quality adjustment mechanism, the set value will not shift excessively due to fatigue, and a good image can be obtained at approximately the center of the setting scale, so it is practical. It is extremely effective in operation and its effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional photoconductor fatigue program control method, FIG. 2 is a block diagram showing an embodiment of the photoconductor fatigue program control method according to the present invention, and FIG. 3 is another embodiment according to the present invention. A block diagram showing an example, FIGS. 4 to 6 are explanatory diagrams of more specific embodiments of the present invention, and FIG. 7 is an explanatory diagram of an embodiment using a mechanical mechanism of the present invention. DESCRIPTION OF SYMBOLS 1... Program control device, 2... Copy number detection device, 3... Charge amount adjustment device, 4... Exposure amount adjustment device, 5... Development bias potential adjustment device, 6...
...Program step progress control device, 7...Exposure amount detection device, 11...Photosensitive drum, 12...Illumination lamp, 13...Original, 14...Lens, 15
. . . Charging device, 16 . . . Developing device, 19 . Development bias potential control device.

Claims (1)

[Scope of Claims] 1. Fatigue compensation for charge amount, exposure amount, developing bias potential, etc. during copying by Pumgram set according to fatigue characteristics predicted for the number of copies of a photoreceptor in an electrophotographic device. In the program control method for compensating for fatigue of the photoreceptor by controlling factors according to the number of copies, the exposure amount during copying is detected and the progress rate of the program is corrected based on the detected value. A program control method for compensating for fatigue of a photoreceptor in an electrophotographic apparatus, characterized in that: 2. Photosensing in the electrophotographic apparatus according to claim 1, wherein the amount of exposure during copying is detected by a photoelectric conversion element provided in the vicinity of the photoreceptor and adjacent to the irradiation surface of the photoreceptor. A program control method to compensate for body fatigue. 3. A program control method for compensating for fatigue of a photoreceptor in an electrophotographic apparatus according to claim 1, wherein the amount of exposure during copying is detected by measuring a current flowing through the photoreceptor. 4. A program control method for compensating for fatigue of a photoreceptor in an electrophotographic apparatus according to claim 1, wherein the exposure amount during copying is detected by the set value of an exposure amount adjustment device. 5. Fatigue compensation factors such as the amount of charge during copying, the amount of exposure, and the developing bias potential are adjusted according to the number of copies by a program set according to the fatigue characteristics predicted for the number of copies of the photoreceptor in the electrophotographic device. In the program control method for compensating for fatigue of the photoreceptor, the exposure amount during copying is detected, and the progress of the program is corrected based on the detected value and the total number of copies. A program control method for compensating for fatigue of a photoreceptor in an electrophotographic apparatus, characterized in that: 6. Photosensing in the electrophotographic apparatus according to claim 5, wherein the amount of exposure during copying is detected by a photoelectric conversion element provided near the photoreceptor and adjacent to the irradiation surface of the photoreceptor. A program control method to compensate for body fatigue. 7. A program control method for compensating for fatigue of a photoreceptor in an electrophotographic apparatus according to claim 5, wherein the amount of exposure during copying is detected by measuring the current flowing through the photoreceptor. 8. A program control method for compensating for fatigue of a photoreceptor in an electrophotographic apparatus according to claim 5, wherein the exposure amount during copying is detected by the set value of an exposure amount adjustment device.