JPH01167873A - Cleaning device for photosensitive body - Google Patents

Abstract

PURPOSE:To obtain an image having a high quality extending over a long period of time by setting a load of a cleansing blade to the minimum value required for eliminating a toner on a photosensitive body. CONSTITUTION:Immediately before a transferred residual toner reaches an opposed position of a cleaning blade 2, a cam 30 is turned and by energizing force of a spring 24, the blade 2 is pressed against a photosensitive body 1. Subsequently, a load determined by a signal of image information at the time of forming a latent image, image information on the photosensitive body after a toner image has been formed, information related to whether a mechanical trouble exists or not, or image information of a transferred toner image, etc., is applied to the blade 2. That is, a state that any of cams 32, 34 and 36 does not push a lever 5, or a state that one cam of them pushes the lever 5 is selected. This load is set to the minimum value required for eliminating the residual toner quantity. Image information on the photosensitive body 1 is detected by a photosensor which has been allowed to face the photosensitive body 1, and a trouble is detected by a feed form detecting microswitch or said photosensor. In such a way, an image having a high quality can be obtained extending over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device for a photoconductor of an electrophotographic apparatus, and more particularly to a photoconductor cleaning device of a type in which a cleaning blade is brought into pressure contact with a rotating photoconductor.

[Prior Art] In general, image forming apparatuses such as transfer-type electrophotographic copying systems use a rotating drum-type image carrier, that is, a photoreceptor, which has a photoconductive photosensitive layer on the outer surface, and while the photoreceptor is rotated. An electrostatic latent image is formed on the photosensitive layer and developed with toner, and the resulting toner image is transferred to recording paper. After the transfer is completed, residual toner adhering to the outer peripheral surface of the photoreceptor is removed and cleaned by a cleaning device, and an electrostatic latent image is formed again, and a new image is transferred. It is well known that in general image forming apparatuses, the residual toner is peeled off and removed by a method of pressing a blade member, which has a simple structure and has a high cleaning effect.

The setting of the blade load in the conventional blade pressure contact method is, for example, as shown in FIG. 5, when the holding member 3 that holds the cleaning blade 2 is integrated with the lever 5,
The cleaning blade 2 is pivoted on and biased by a spring 6.
As shown in FIG. This has been carried out either by pressing the cleaning blade against the photoreceptor 1 or by holding a holding member that holds the cleaning blade in a fixed position and pressing the cleaning blade against the photoreceptor by the elasticity of the cleaning blade.

In all of these cases, the load on the cleaning blade is set to be constant.

[Problems to be Solved by the Invention] In the above-mentioned cleaning blade load setting method, the load value is usually the maximum amount of toner applied, that is, the cleaning of untransferred toner images (solid images) that occur due to machine trouble, etc. The load value is set to a value that is sufficiently possible. However, there is a significant difference between the amount of untransferred toner at the time of trouble and the amount of transferred residual toner under normal use conditions, and the load value of the cleaning blade described above is excessive as the load value under normal use conditions.

Applying an excessive load to the cleaning blade during normal use will accelerate wear and damage to the blade edge and deteriorate its durability. Furthermore, if the load on the cleaning blade is increased and a blade pressure release mechanism is used, uneven rotation of the drum will occur, which may cause misalignment during latent image formation, toner image formation, transfer, etc. (The larger the set load of the blade, the greater the unevenness of drum rotation during crimping and release of crimping.) As mentioned above, the method of setting the cleaning blade load to a constant value does not provide optimal conditions during long-term use. This has the disadvantage of increasing the frequency of parts replacement.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a photoconductor cleaning device in an electrophotographic apparatus, which has a long life of a cleaning blade and a photoconductor, and which does not cause image distortion due to uneven rotation of the photoconductor.

[Means for Solving the Problems] In order to achieve the above object, the apparatus of the present invention is a photoconductor cleaning device having a drum-shaped cleaning blade that is pressed against the circumferential surface of a rotating photoconductor. The load of the plow cleaning blade is set based on the input signal value effective for determining the load value of the plow cleaning blade. Effective input signals for determining the load value of the cleaning blade include image information during latent image formation, image information on the photoreceptor after toner image formation, information on the presence or absence of mechanical trouble, or information on the toner image after transfer. There is image information, etc., and a preset load value is selected based on these signals, and a cleaning operation is performed based on the blade load value.

[Function] The blade cart value required to clean the toner on the photoreceptor of an electrophotographic copying machine is the M/A value, that is, the unit area 1 on the surface of the photoreceptor. Toner amount (R
g), and when M/A11fl is small, the blade load value may also be small. In the present invention, the blade load value is determined based on the information related to the M/A value, so that an unnecessarily excessive blade load value is not used.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing the main parts of a color copying machine to which the present invention is applied, and FIGS. 2 to 4 are enlarged cross-sectional views showing the drive section of the cleaning device in FIG. 1.

In the figure, 1 is placed on a cylindrical conductive drum.
A color toner image is formed by rotating a photoreceptor made of an organic optical semiconductor (OPC) in the direction of the arrow shown in the figure.

In other words, the photoreceptor 1 cleaned by the cleaning device 11
The surface of is uniformly charged by a charger 8, and laser exposure 9 is irradiated to form a charged latent image corresponding to a toner image of each color, and the toner of that color is transferred to a developing device 12 (13, 1).
4). The charging exposure and development described above is repeated once for each color, thus three times for three colors. The above laser exposure is main scanned in the direction perpendicular to the paper surface and combined with sub-scanning by the rotation of the drum to form charged latent images corresponding to yellow, magenta, and cyan images on the surface of the photoreceptor. The image information is provided by a conventionally known color separation image reading device and image processing device. In this way, a color toner image is formed on the photoreceptor 1, and to explain the time course, when the photoreceptor 101 rotates, a charged latent image corresponding to the yellow toner created by the laser exposure 9 is developed by the yellow toner. By applying a direct current to the device 12, the developing roller 12
' to form a yellow toner image on the surface of the photoreceptor 1. At the second rotation of the photoreceptor 10, magenta toner is similarly applied to the surface of the photoreceptor 1 by the developing roller 13- of the magenta toner developing device 13. Further, during the third rotation of the photoreceptor, cyan toner is adhered by the developing roller 14- of the cyan toner developing device 14.

The color image thus formed on the surface of the photoreceptor is transferred by a transfer device 16 onto recording paper fed from a paper feeder 15. The transferred recording paper is separated by a separator 17 and then sent to a fixing device 18, where the three-color image is fixed on the recording paper. Since the three-color images are combined on the photoreceptor 1 and transferred onto the recording paper at one time, a good image and quality without color shift can be obtained. In the above process,
The photoreceptor first passes through the cleaning device 11 while carrying a yellow toner image, and then passes through the cleaning device 11 while carrying yellow toner and magenta toner images. In this manner, when an untransferred image passes, the cleaning device 11 is deactivated, and the cleaning device 11 is activated at other times. The cleaning device will be explained below with reference to FIGS. 2 to 4. FIG. 2 is a sectional view of a cleaning device showing a first embodiment of the present invention. 2 is a cleaning blade constituting the main cleaning means and is held by the holding member 3;
The holding member 3 is also fixed to the lever 5. Lever 5
is pivotally attached to the shaft 4, and is urged by a spring 24 so as to rotate counterclockwise at all times. The cam 30 located on the left side of the lever 5 is used to release the operation of the cleaning device, so it is rotated around the shaft 31. When the lever 5 is pushed, the lever 5 is rotated clockwise around the shaft 4 to perform cleaning. Separate the blade 2 from the photoreceptor 1. Cam 32.34
．． 36 are rotated around @33, 35, and 37 respectively, and the levers 5 are rotated counterclockwise by different rotation angles to apply mutually different loads to the cleaning blade 2.

25 is a gab (G) of about 0.2 to 0.3 INR between the toner collection port and the arm photoconductor 1, which constitutes the toner receiver.
It is arranged such that it is rotatably driven in the direction of the arrow, and a positive DC voltage of 500 mm is applied. A toner guide 26 guides the toner from above the toner collection roller 3 to the lower groove of the casing 28. 27 is rotated by a screw so that a spiral blade sends toner into a toner reservoir.

Next, the operation of the cleaning device will be explained. As mentioned above, when an untransferred toner image passes, the cleaning device does not operate, so the cam 30 pushes the lever 5, and the cleaning blade 2 moves from the photoreceptor 1! It is held at a position between 1 and 1. Immediately before the residual toner after transfer reaches the position facing the cleaning blade 2 of the cleaning device, the cam 30 is rotated to the position shown in FIG. Ru. At this time, a load determined by signals such as image information during latent image formation, image information on the photoreceptor after toner image formation, mechanical trouble information, or image information of the toner image after transfer is applied to the cleaning blade 2. It will be done. That is, a state in which none of the cams 32, 34, and 36 pushes the lever 5 (the state shown in FIG. 2) or a state in which any one of the cams pushes the lever 5 is selected. However, the rotation angle of the cam is controlled to be constant.

In this way, the glm of the cleaning blade is the minimum value necessary to remove the residual toner hang-up at that time. This state is maintained throughout the passage of the imaged portion. In this way, the residual toner is peeled off from the surface of the photoreceptor by the cleaning blade 2 and guided into the lower groove of the casing along the path shown by the arrow. That is, since the toner collection roller 25 is applied with a voltage of opposite polarity to the toner, it draws the toner and does not leak it downward. The toner on the toner collection roller 25 is sent onto the toner guide 26 as the toner collection roller rotates.

In this apparatus, troubles in mechanical operation are likely to be detected by a microswitch for detecting paper supply or a photosensor placed on the photoreceptor.

Further, image information on the photoreceptor is detected by a photosensor facing the photoreceptor. Further, when a trouble occurs in the mechanical operation, the cam 32 is activated to obtain a blade load that can clean the maximum amount of toner adhesion without any trouble. In this way, when a problem occurs in mechanical operation, the blade load is increased and the photoreceptor is rotated one or more revolutions according to a certain sea fence. After the photoreceptor is thoroughly cleaned, the cam 32 is moved to the position shown in FIG. It is rotated until.

After eliminating the cause of the trouble, when a new copying operation is started, the blade load during normal operation is applied.

FIG. 3 is a sectional view showing a second embodiment of the present invention. The second embodiment is similar to the first embodiment except that the cams 32, 34, 36 of the first embodiment are replaced by multi-stage solenoids 38.

That is, in order to determine the load value of the cleaning blade, the blade load value of each step is selected based on the effective input signal value, and cleaning is performed.

FIG. 4 is a sectional view showing a third embodiment of the present invention, which is similar to the first embodiment except that the cams 32, 34, and 36 of the first embodiment are replaced with cams 39. This is similar to the example. The cam 39, unlike the cams 32, 34, and 36, is of a type that can be rotated to any rotation angle. The input signal value for determining the load value of the cleaning blade is a continuous value.

In this case, the rotation angle of the cam 39 can also be changed continuously.

1. Effects of the Invention] As explained above, in the cleaning device of the present invention, the load of the cleaning blade is set to the minimum value necessary to remove the toner on the photoreceptor, so that it can be used normally. The load on the cleaning blade is reduced. Therefore, there is less wear on the cleaning blade and the photoreceptor, and their lifespan is extended.

Further, in the type in which the cleaning blade is brought into and out of pressure contact with the photoreceptor, uneven rotation of the photoreceptor due to contact and release of pressure contact is reduced, and the problem of image distortion due to uneven rotation of the photoreceptor is improved.

In this way, the present invention provides a cleaning device that can obtain high-quality images over a long period of time using a conventional blade cleaning method that is simple, highly stable, and has good cleaning efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of a color copying machine to which the present invention is applied, and FIGS. 2 to 4 are enlarged views showing the cleaning device 11 in the first to third embodiments excluding the driving part. This is a new view, and FIGS. 5 and 6 are cross-sectional views showing a conventional cleaning device. 1... Photoreceptor, 2... Cleaning blade, 3...
...Holding member, 4...Shaft, 5...Lever, 6...
Spring, 7... Weight, 8... Charger, 9... Laser exposure, 11... Cleaning device, 12... Developing device, 15... Paper feeding device, 16... Transfer Vessel, 17...
・Separator, 18... Fixing device, 24... Spring, 25.
...Toner collection roller, 26...Gutter guide, 27
...Screw, 28...Casing, 30.32
．． 34.36.39...Cam, 31.33.35.3
7.40...Axis, 38...Multi-stage solenoid. Applicant's agent Hiromitsu Fujimoto 1st session $2 Figure 3 3rd session Figure 4

Claims (1)

[Claims] In a photoconductor cleaning device having a cleaning blade formed in a drum shape and pressed against the circumferential surface of a rotating photoconductor, the load of the cleaning blade is determined based on an input signal value effective for determining the load value of the cleaning blade. A photoreceptor cleaning device characterized in that: