JPS6230284A - Blade cleaning method for electrophotographic photosensitive drum - Google Patents

Abstract

PURPOSE:To always attain a stable and excellent cleaning even if there are aging and environmental changes by abutting a blade due to the action of gravity. CONSTITUTION:The blade 3 having an elastic cutting knife 3 is supported on a supporting spindle 5 rotatably installed through a blade holding fitting 4 so as to come into contact with a photosensitive drum 1. The installation angle of a connection between the blade 3 and the photosensitive drum 1 is selected so as to obtain an optimum cleaning effect. An arm 6 equipped with a vertical weight 7 is fitted to the spindle 5, and the blade 3 is pressed to the photosensitive drum 1 in the state most effective for toner cleaning by adjusting the vertical weight 7. The contact between the blade 3 and the photosensitive drum 1 is set above the horizontal center line of the photosensitive drum 1 so that a remainder toner scraped by the blade 3 can fall downward along the surface of the photosensitive drum 1.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a blade cleaning method for scraping residual toner on an electrophotographic photosensitive drum, which is a toner holding member, in an electrophotographic recording device such as an electrophotographic copying machine. It is about improvement.

(Conventional Technique) Generally, a transfer type electrophotographic copying machine uses a rotating photosensitive drum having a photoconductive photosensitive layer on its outer circumferential surface, and electrostatic latent material is applied to the photosensitive layer while rotating the photosensitive drum. An image is formed, developed with toner, and the resulting toner image is transferred to recording paper. After the transfer is completed, the residual toner on the outer peripheral surface of the photosensitive drum is removed and cleaned by a cleaning device, and an electrostatic latent image is formed again, and a new image is transferred.

Within such a short period of time during the photosensitive drum phase □
A so-called blade cleaning device using a cleaning blade is often used as an efficient cleaning method.

This blade cleaning device is designed so that when a cleaning blade made of a hard rubber plate made of polyurethane, silicone, polybutadiene, etc. is pressed against the circumferential surface of the photosensitive drum, the edge portion of the tip of the blade slides uniformly and with equal pressure on the circumferential surface of the drum. What I did was □.

Pt54 diagram shows a conventional blade cleaning device,
This figure shows biasing means for pressing two different blades against the photosensitive drum.

In FIG. 4(a), one side end of a plate-shaped blade 33 is supported by a support member 34, and the blade 33 supported by the support member 34 is pivoted about a support shaft 35 in the direction of arrow B. The biased spring member 36 causes the tip 33a of the blade 33 to come into sliding contact with the photosensitive drum 31 rotating in the A direction. Here, the above-mentioned support shaft 35 is provided on the upstream side and the downstream side with respect to the normal line ○■ at the pressure contact portion with the blade tip 33a of the photosensitive drum 31, so that the necessary pressing force and the accompanying pressure force are required. The cleaning effect is also different, but the cleaning effect is better when it is provided on the downstream side as shown in the figure. When the support shaft 35 is provided on the downstream side of bending or when it is provided on the upstream side, the blade tip 33a can be brought into pressure contact with the photosensitive drum 31 with an appropriate pressing force, without damaging the photosensitive layer, and ensuring good leaning. The condition is that the above spring member 3
By selecting or adjusting 6, processing is performed to satisfy that condition.

FIG. 4(b) shows one side end of a plate-shaped blade 43 supported by a support member 44, the support member 44 adjusted to an appropriate position, and the tip 43a of the blade 43 rotated in the direction A. The blade 41 is designed to slide into contact with the circumferential surface of the photosensitive drum 41, and an appropriate pressing force is generated by the restoring force generated by the deformation of the blade 43, which is an elastic body.

[Problem that the invention seeks to solve]

In order to obtain a good cleaning effect with a blade cleaning device, it is necessary for the blade to contact the photoreceptor drum with an appropriate pressing force, and the range of permissible pressing force is quite narrow (with delicate adjustments, the was being fulfilled.

However, the cleaning performance of conventional blade cleaning devices often deteriorates significantly after long-term use.

The present inventors conducted various investigations into the causes and found that Fig. 4 (
In the cleaning device of a), the elastic change of the spring member 36 over time is often the cause;
In the cleaning device shown in Figure (b), the blade 43
It has become clear that this is caused by changes in elastic properties over time or by environmental factors such as temperature and humidity. In many cases, both were the cause.

SUMMARY OF THE INVENTION An object of the present invention is to provide a blade cleaning method that consistently performs good cleaning even with time or environmental changes.

[Means for solving problems]

The above object is achieved by a blade cleaning method for scraping toner by bringing a blade into pressure contact with a rotating electrophotographic photosensitive drum, which is characterized in that the blade is brought into pressure contact with the rotating electrophotographic photosensitive drum by the action of gravity.

〔Example〕

1 to 3 show embodiments of the present invention, and the illustrated embodiments will be described below.

1 is a photosensitive drum that rotates in the direction of arrow A, and after each operation of charging, exposure, development, transfer, and cleaning has been performed, it is placed on a circular plate 2 with a small i Clean residual toner.

Reference numeral 3 denotes a blade having an elastic sharpener, which is supported via a blade holding fitting 4 on a rotatably provided support shaft 5 so as to be in contact with the photosensitive drum 1 . The installation angle between the blade 3 and the tangent to the photosensitive drum 1 is selected so as to obtain the optimum cleaning effect. Reference numeral 6 denotes an arm provided with a weight 7, which is attached to the shaft 5, and by adjusting the weight 7, the blade 3 is pressed against the photosensitive drum 1 in a state that is most effective for toner cleaning. Blade 3 and photosensitive drum 1
The tangent line is set above the horizontal center line of the photosensitive drum 1 so that the residual toner scraped off by the blade 3 falls downward along the surface of the photosensitive drum 1.

Reference numeral 8 denotes a toner conveying roller made of an elastic body, which is disposed below the blade 3 and parallel to the photosensitive drum 1 so as to intercept falling residual toner, and is rotatably provided on the support fitting 10 by a core shaft 9.

This conveyance roller 8 is moved by the photosensitive drum 1 in the direction of arrow B.
As shown, flange portions 11 are formed on both edges of the conveying roller 8 outside the required width W for image formation to be larger than the diameter of the row 78.
．． 12 or flange portions 13.1 formed on both edges of the photosensitive drum 1
4.

15 is a fixed shaft on which the support fitting 10 is rotatably attached; 16;
has one end attached to the support bracket 10 and the other end attached to the spring fixing bracket 1
7, the photosensitive drum 1 and the conveying roller 8 are placed in contact with each other via the flanges 11.12 or 13.14 as shown in PtIJ2 (a) and 3 (a), so image formation is possible. A gap T is created within the required width W, and the residual toner that falls from this gap T falls out, so the spring 1
By adjusting the tension of 6, Fig. 2(b), f53
As shown in Figure (b), the conveying roller 8 is operated on the photosensitive drum 1 within the required width W for image formation, with a gap smaller than the toner diameter, or in contact with the photosensitive drum 1.

18 is a scraping blade for removing residual toner on the conveying roller 8;
It is attached to a rotatably provided pongee 19, and is arranged so as to be in close contact with the conveying roller 8 by means of a spring 21 attached to a spring fixing holder 20.

Reference numeral 22 denotes a cleaning box, and the toner scraped off by the scraping blade 18 is accumulated in a storage area at the bottom of the 22nd part.

Since the present invention is configured as described above, the residual toner on the photosensitive drum 1 is scraped off by the blade 3, falls along the surface of the photosensitive drum 1, and is removed from the photosensitive drum 1.
The particles adhere to the conveyance roller 8 which is being rotated by the driven rollers and are conveyed, are scraped off from the conveyance roller □8 by the scraper blade 18, and are accumulated at the bottom of the cleaning box 22.

At this time, the conveying roller 28 is arranged so as to be in line contact with the photosensitive drum 1 with a gap smaller than the toner diameter, so that the residual toner is strongly pressed against the surface of the photosensitive drum 1 by the pressing force of the conveying roller 8. Therefore, the residual toner can be completely removed by the blade without causing toner filming phenomenon, and the surface of the photosensitive drum 1 may be damaged due to damage to the surface of the conveying roller 8 caused by the pressing force of the scraping blade 18. Furthermore, even if the residual toner contains a small amount of carrier, the surface of the photosensitive drum 1 will not be damaged by the conveyance roller 8, so the life of the photosensitive drum will be considerably longer. Become,
It was able to withstand long hours of driving.

It goes without saying that the present invention is not limited to the above embodiments, but includes all modifications and changes that fall within the scope of the claims.

〔Effect of the invention〕

The blade cleaning device of the present invention has a movable heavy equipment 7 on the lever 6, and by moving it, it is possible to finely adjust the moment (horizontal component pressure of the arm x weight) relative to the support shaft 5. By finely adjusting the pressing force on the photosensitive drum 1 in step 3 and fixing the position of the heavy equipment 7 on the lever 6 under optimal conditions, it was possible to maintain stable and good leaning characteristics over a long period of time. .

Furthermore, as shown in this embodiment, by providing the support shaft 5 on the downstream side with respect to the normal line of the pressure contact portion of the blade 3 to the photosensitive drum 1, a favorable leaning condition can be set. became.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
Figure fJfJ1 is a cross-sectional view, Figure 2, and Figure PIIJ3 are conveyance.
□ It is a front view of each embodiment showing the relationship between the roller and the photosensitive drum. Figures 4(a) and 4(b) show the conventional blade cleaner i.
1 shows a cross-sectional view of the cleaning device. 1... Photosensitive drum 3... Blade 4... Holding metal fitting 5... Support shaft 6... Arm
7...Applicant Konishiroku Photo Industry Co., Ltd. Figure 1

Claims (2)

[Claims] (1) A blade cleaning method for scraping toner by bringing a blade into pressure contact with a rotating electrophotographic photosensitive drum, the blade cleaning method being characterized in that the blade is brought into pressure contact with the rotating electrophotographic photosensitive drum by the action of gravity. (2) With respect to the normal line at the pressure contact portion of the photosensitive drum,
2. The blade cleaning method according to claim 1, wherein the support shaft of the blade is provided on the downstream side in the rotational direction of the drum.