JPH0581860U - Electrophotographic printer cleaning device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a cleaning device for an electrophotographic printer capable of accurately preventing toner from flowing into the inside of a cleaning blade. The cleaning blade 6 has a lower contact pressure when the printing operation is stopped than when the printing operation is performed, for example, about 2 g / mm when the printing operation is performed and about 0.2 to 0.3 g / mm when the printing operation is stopped. Was brought into contact with the photosensitive drum 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an electrophotographic printer, and more particularly to a cleaning device of a type in which residual toner on a photosensitive drum is cleaned by a cleaning blade.

[0002]

[Prior Art]

 FIG. 1 is a configuration diagram around a photosensitive drum centering on an opening / closing mechanism of a cleaning blade. In FIG. 1, reference numeral 1 is a photosensitive drum. Around the photosensitive drum 1, a charger 2 is arranged in an image forming process order. , An optical writing head 3, a developing device 4, a transfer / separator 5, a cleaning device including a cleaning blade 6, and a static eliminator 7 are arranged so that a well-known electrophotographic process is sequentially executed.

The cleaning blade 6 is arranged in a so-called counter so that its tip is oriented with respect to the rotation direction of the photoconductor drum 1, and the photoconductor is provided with an appropriate contact pressure (for example, about 2 gr / mm) during printing operation. The surface of the photosensitive drum 1 is cleaned by contacting the drum 1.

By the way, if the cleaning blade 6 is kept in pressure contact with the surface of the photoconductor, the photoconductor is scratched or deteriorated. Particularly, the selenium photoreceptor is easily affected. Therefore, in order to solve this problem, the cleaning blade 6 is generally opened from the photosensitive drum 1 when the printing operation is stopped.

The opening / closing mechanism of the cleaning blade 6 will be described. A bracket 8 holding the cleaning blade 6 and having an arm 9 at its tip is swingable around a support shaft 10. The arm 9 is engaged with a front end portion 12a of a hook-shaped lever 12 which rotates about a support shaft 11, and a pin at the lower end thereof is loosely fitted in a long hole of a link 14 of a solenoid 13. The other end of the tension coil spring 15 whose one end is locked to the link 14 is locked to the lower end of the lever 12 and urges the lever 12 clockwise. Therefore, the arm 9 engaged with the tip portion 12a of the lever 12 is urged to swing in the counterclockwise direction.

FIG. 2 is an enlarged configuration diagram of the mounting portion of the cleaning blade. A fixed frame 16 is provided on the upper portion of the bracket 8, and a support shaft is provided between the inner surface of the fixed frame 16 and the inner surface of the bracket 8. Both ends of the spiral spring 17 that is locked to 10 are elastically contacted so as to urge the cleaning blade 6 in the direction to open it.

During the printing operation, the solenoid 13 is turned on, the link 14 is pulled to the left in FIG. 1, and the lever 12 is rotated in the clockwise direction. Then, the arm 9 is pressed downward by the lever 12a, which causes the bracket 8 to swing counterclockwise around the support shaft 10 while compressing the spiral spring 17 to move the cleaning blade 6 to the photosensitive drum 1. Press against. The contact pressure (cleaning pressure) at this time is about 2 gr / mm 2 as described above.

When the printing operation is completed, the solenoid 13 is turned off, the link 14 is returned to the original position, the pressure applied to the arm 9 by the tip portion 12a of the lever 12 is released, and the bracket 8 is wound by the spiral spring 17. Is swung clockwise by the elastic force of to clean the cleaning blade 6 from the photosensitive drum 1.

[0009]

[Problems to be solved by the device]

 3 (a), (b), and (c) are explanatory views showing a problem caused by opening and closing the cleaning blade.

As shown in (a), during the printing operation, the cleaning blade 6 is in pressure contact with the photosensitive drum 1, and scrapes off the toner 18 remaining on the surface of the photosensitive drum 1, but (b) As shown in FIG. 5, the toner lump 18a may wrap around and adhere to the inner surface of the cleaning blade 6 due to static electricity, vibration or the like through the gap D generated when the cleaning blade 6 is separated from the photosensitive drum 1.

The toner lump 18a that has wrapped around the inside of the cleaning blade 6 in this way adheres to the photosensitive drum 1 during the next printing operation, as shown in (c) of FIG. There is a problem that causes image defects because it cannot remove static electricity or charge.

In order to prevent the toner from wrapping around the inside of the cleaning blade 6, there is a device in which the photosensitive drum 1 is slightly reversely rotated and then stopped, but it is necessary to completely prevent the toner from wrapping around. The reality is that you cannot do it.

The present invention has been made based on such a background, and it is an object of the present invention to provide an electrophotographic printer cleaning device capable of accurately preventing toner from flowing into the inside of the cleaning blade. To aim.

[0014]

[Means for Solving the Problems]

 In order to achieve the above object, in the present invention, when the printing operation is stopped, the cleaning blade is brought into contact with the photosensitive drum at a contact pressure lower than that during the printing operation.

More specifically, during the printing operation, the cleaning blade is brought into contact with the photosensitive drum with a contact pressure of 2 gr / mm, and when the printing operation is stopped, the contact pressure is about 0.2 to 0.3 gr / mm. The cleaning blade comes in contact with the photosensitive drum.

[0016]

[Action]

 When the printing operation is stopped, the cleaning blade is not completely released from the photoconductor drum, but it is contacted with a light contact pressure that does not damage the photoconductor. To prevent.

[0017]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. The same parts as those in the conventional example are designated by the same reference numerals. FIG. 4 is an enlarged configuration diagram of a mounting portion of the cleaning blade of the cleaning device according to the embodiment, which corresponds to FIG.

In this embodiment, the spiral spring 19 is provided so as to urge the cleaning blade 6 in the direction in which the cleaning blade 6 is brought into pressure contact with the photosensitive drum 1. That is, the spiral spring 19 is provided in the opposite direction to the conventional spiral spring 17 shown in FIG.

During the printing operation, the solenoid 13 shown in FIG. 1 is turned on in the same manner as described above, and the arm 9 is pressed by the tip portion 12a of the lever 12, so that the bracket 8 is turned around the support shaft 10. The cleaning blade 6 is oscillated in the clockwise direction and brought into pressure contact with the photosensitive drum 1 at a contact pressure of about 2 gr / mm.

As described above, when the printing operation is stopped, the solenoid 13 is turned off and the pressing force on the arm 9 is released by the tip portion 12a of the lever 12 in the same manner as described above. Since the cleaning blade 6 is biased toward the photosensitive drum 1 by the winding spring 19, the cleaning blade 6 is brought into light contact with the photosensitive drum 1 by this spring force. The contact pressure at this time is set to about 0.2 to 0.3 gr / mm by selecting the spring constant.

[0021]

[Effect of the device]

 According to the present invention, even when the printing operation is stopped, the cleaning blade is brought into contact with the photosensitive drum with a contact pressure smaller than that during the printing operation. Therefore, it is possible to completely prevent the residual toner from wrapping around the inside of the cleaning blade. As a result, it is possible to accurately suppress the occurrence of an image defect due to the toner lump adhering to the photosensitive drum.

[Brief description of drawings]

FIG. 1 is a configuration diagram around a photosensitive drum centering on an opening / closing mechanism of a cleaning blade.

FIG. 2 is an enlarged configuration diagram of a cleaning blade mounting portion according to a conventional example.

FIG. 3 is an explanatory diagram showing a problem caused by opening and closing a cleaning blade.

FIG. 4 is an enlarged configuration diagram of a cleaning blade mounting portion according to an embodiment of the present invention.

[Explanation of symbols]

 1 Photosensitive drum 6 Cleaning blade 19 Vortex spring

Claims (2)

[Scope of utility model registration request] 1. A cleaning device for an electrophotographic printer, which uses a cleaning blade to clean the surface of a photosensitive drum that has been subjected to an electrophotographic process in the order of charging, optical writing, development, and transfer / separation. A cleaning device for an electrophotographic printer, wherein the cleaning blade is brought into contact with the photosensitive drum at a contact pressure lower than that during operation. 2. The cleaning blade is brought into contact with the photosensitive drum at a contact pressure of about 2 gr / mm during a printing operation, and about 0.2 to 0.3 g when the printing operation is stopped.
2. The cleaning device for an electrophotographic printer according to claim 1, wherein the cleaning blade is brought into contact with the photosensitive drum with a contact pressure of r / mm.