JPS61140975A - Cleaning device - Google Patents

Abstract

PURPOSE:To improve the wear resistance at the top end of a cleaning blade and to made the satisfactory cleaning over a long period of time possible by constituting the cleaning blade of a thin sheet, disposing the blade on the cleaned side of an image carrying body so as to incline toward said side and specifying the angle with the tangent of the image carrying body at the contact point. CONSTITUTION:The cleaning blade is constituted of the thin sheet blade and is disposed on the cleaned side of the image carrying body so as to incline toward said side. The blade is so constituted that the angle between the cleaning blade and the tangent of the image carrying body at the contact point of the image carrying body as designated as theta attains theta<=30 deg.. The thin sheet blade 8 is constituted of a resin such as polyethylene terephthalate or biaxially stretched PP or metal, ceramics, etc. The thickness (h) is preferably 30mum-500mum. A 5<=l/h<=100 range is applied and a 10<=l/h<=30 range is more preferable in the relation between the free end length l and the thickness (h) of the thin sheet blade. The uniform contact of the top end of the cleaning blade with the image carrying body under the low load is made possible and the satisfactory cleaning performance is maintained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a cleaning device, and in particular, to a cleaning device used in an electrophotographic copying device, an electrophotographic printer, etc., for removing residual toner adhering to the surface of an image carrier. The present invention relates to a cleaning device.

[Prior art]

-a, the cleaning blade used in the cleaning device is made of polyurethane and has a thickness of 2 to 5 days, a free end length of about 10 to 20 tm, and a rubber hardness of 60. It was ~80Hs.

The factors for determining such a value are:
These include the ability of the cleaning blade to contact the photosensitive drum which is the image carrier, the cleaning ability of the developing agent, and the abrasion resistance of the cleaning blade.

In order to bring the cleaning blade into uniform contact with the photoreceptor drum, it is necessary to press the tip against the photoreceptor drum with a certain amount of load in order to cover the unevenness of the tip. Even in the case of a trail method in which the image bearing member is tilted toward the uncleaned side, or in the case of a one-way counter method in which the image carrier is tilted toward the cleaned side, if the image bearing member is not brought into contact with the photoreceptor drum under appropriate conditions, If toner is located at the tip of the cleaning blade or slips through this area, abnormal vibrations (squeaks) of the cleaning blade, excessive scraping of the photoconductor drum, or excessive wear of the cleaning blade occur. Oops.

The cleaning blade is generally made of polyurethane and has a thickness of 10 mm or more, but the disadvantage of this method is that the cleaning action depends on the force that prevents the photosensitive drum from being pressed, so the cleaning blade does not touch the tip of the cleaning blade. There were many cases where the joints were crushed.

That is, as shown in FIG. 6, toner 22 may be deposited between the tip of the cleaning blade 21 and the photoconductor drum due to improper pressure applied to the photoconductor drum 20, which is an image carrier, or to poor precision at the tip of the cleaning blade. If the pressing force is increased to prevent this intrusion or slippage, this may cause the toner particles to rub or become stuck to the photoreceptor drum surface (so-called black spots). Cleaning defects such as these occurred.

In particular, in the case of the counter type, when a load above a certain level is applied, as shown in Figure 7, the entire body, especially the tip, bends and the angle θ changes between installation and actual use. During actual use, the angle θ becomes larger or smaller than the appropriate angle (Fig. 8 (al(bl)).

If the load is too high, the entire cleaning blade will bend and shift, making it easier for the toner to slip through.Also, it is recommended to increase the angle θ to prevent the cleaning blade from shifting. In this case, if the angle θ is too large, abnormal vibrations are likely to occur.Furthermore, the higher the load, the more severe the abrasion of the photoconductor drum and the friction of the cleaning blade become. These drawbacks include shortening the repair and replacement period, and increasing the motor size to increase the rotational torque of the photoreceptor drum, thus increasing the overall cost. U.S. Reissue Patent No. 29632 and U.S. Reissue Patent No. 309
This was a defect common to those shown in No. 24 and others.

In order to eliminate these drawbacks, Japanese Patent Application Laid-Open No. 56-5597
No. 9, JP-A-55-151680 and JP-A-59
10sl No. 689 has been proposed, and the method shown in JP-A-56-55979 uses a composite structure having a rubber elastic base and a hard resin layer, that is, a multilayer blade for cleaning. The bonding structure of the rubber elastic base and hard resin layer that makes up the blade is complex, and the bonded parts are unstable and easily peel off due to changes in the surrounding environment. This becomes noticeable under high humidity conditions, which affects the cleaning performance and also causes deterioration of the rubber elastic substrate.

Furthermore, the device shown in JP-A-55-151680 has a structure in which resin plate blades mixed with carbon fibers or fiber blades having different directions are layered; The flexibility of the material is insufficient, and therefore it is difficult to make uniform contact with the photoreceptor drum, and the precision of the pressing tip (edge precision) is poor (
(Furthermore, it had the disadvantage of increasing costs.

Furthermore, the one shown in JP-A No. 59-101689 has a structure in which a flexible thin plate is attached to the tip of the elastic blade, but in this case, the elastic blade itself is Since the flexible thin plate is pressed against the photoreceptor drum by elastic force, the adhesive part with the elastic blade is unstable and easily peels off, especially under conditions of high temperature and high humidity, and the elastic blade itself deteriorates. This has the disadvantage that it affects cleaning performance and is therefore impractical.

[Purpose of the invention]

This invention eliminates the drawbacks of the conventional ones as described above, and has sufficient cleaning performance because it can make uniform contact with a low load, and can be made compact and inexpensive, and has particularly good cleaning performance. The purpose of the present invention is to provide a cleaning device that has excellent abrasion resistance at the important abutment tip and overall durability, can perform good cleaning over a long period of time, and has a simple configuration. .

[Structure of the invention]

The present invention is a cleaning device that removes residual toner on the surface of an image bearing member by pressing the tip of a cleaning blade into contact with the residual toner, the cleaning blade being constituted by a thin plate blade, The thin plate blade is arranged to be inclined toward the cleaned side, and the thin plate blade has a configuration in which θ≦30°, where θ is the angle formed between the thin plate blade and the tangent to the image carrier at the point of contact with the image carrier. have.

[Embodiments of the invention]

Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows an embodiment of a cleaning device according to the present invention.The cleaning method of this cleaning device is a counter method, and inside a casing 2 which is open on the photosensitive drum 1 side, there are A toner conveying screw 3 is provided at the bottom, and a guide roller 4 is provided above the toner conveying screw 3 and in contact with the photosensitive drum 1.

A spring 6 is connected to the upper part of the inside of the casing 2 from the support frame 5.
A support member 7 is attached to the tip of the spring 6, and a thin blade 8, which is a cleaning blade, is attached to the tip of the inner surface of the support member 7 with double-sided tape and hangs down. has been done.

This thin means field 8 is made of polyethylene terephthalate (PET), biaxially oriented polypropylene, polyimide (
Kapton (manufactured by DuPont), TI Polymer (manufactured by Toshi))
, made of resin such as polyacetal, polybutylene terephthalate, polyamide, or metal, ceramics, etc., and the tangent line between the axis of the thin plate blade 8 and the photoconductor drum 1 at the contact point between the thin plate blade 8 and the photoconductor drum 1. The angle θ between the two is such that θ≦30°.

Furthermore, as shown in FIG.
0 μm to 300 μm is preferable, and the relationship between the free end length i and the thickness h of the thin plate blade is 5≦l/h≦1.
A range of 00 is applicable, and a range of 10≦It/h≦60 is particularly preferred.

In this case, the preferred range of thickness h varies slightly depending on the material of the cleaning blade, but the strength of the material, stiffness,
In view of the difficulty in attaching and assembling the cleaning blade, the limit is 30 μm, and if it is thinner than this, the attachment may easily bend during the operation. Therefore 50μ
If it is more than m, it can be easily done.

Additionally, in order to uniformly contact the photoreceptor drum as a cleaning blade, a certain degree of flexibility is required;
Since general-purpose materials can be used, h is 500μ.
A thickness of 300 μm or less is suitable, and a thickness of 300 μm or less is most suitable for practical use.

Furthermore, the reason for considering It/h is that if the cleaning blade has a thickness h within the above range, it is easy to bring the cleaning blade into uniform contact with the photoreceptor drum.

Furthermore, the tip of the thin plate blade is brought into contact with the surface of the photoreceptor drum by the spring 6;
The load component F in the vertical direction of the tangent to the photosensitive drum at the contact point is 1 to 30 g/am.

An experimental example using the cleaning device configured as described above will be described below.

[Experiment example-■]

In this experimental example, a leaning device as shown in FIG. 3 was used.

That is, in this cleaning device, a toner conveying screw 3 is provided at the lower part of a casing 2 that is open on the side of the photoreceptor drum l, and a toner guide plate 10 is provided at the lower part of the opening that slopes upward from below. established,
A toner scraping member 11 is provided on the toner guide plate 10, and a spring 13 whose rear end is supported is provided on the upper and lower surface of the casing 2, and the urging force of the spring 13 causes the tip of the cleaning blade 8 to move as follows. A support member 12 is disposed on the spring 13 so as to act on the photoreceptor drum 1 at the stated value.

The cleaning blade 8 is made of polyethylene terephthalate (PET) and has a thickness h=25 (Jun.
, free end length 1=5tm, θ=25°, F,=about IQg/
The condition is a11, and the spring 13 is a phosphor bronze leaf spring.

The photoreceptor drum l is made of selenium-based material and amorphous silicon material, each having a weight of 30,000 yen.
As a result of copying twice and copying 70,000 times, in both cases, the cleaning blade 8 can be brought into uniform contact in cooperation with the biasing force of the spring 13, and the toner on the surface of the photoreceptor drum 1 can be removed. It was possible to reliably remove the particles and obtain a good leaning result. Furthermore, it was possible to continue the cleaning operation in the same state, that is, without replacing the cleaning blade.

[Experiment example-■]

In this experimental example, a leaning device as shown in FIG. 4 was used.

That is, this cleaning device is almost the same as that used in Experimental Example-1, and the same members are given the same numbers and explanations are omitted. A guide roller 15 is provided which is in contact with the guide roller 15, and a scraping base 16 is also provided.

Then, the cleaning blade 8 is made of polyethylene terephthalate (PET), and the photosensitive drum 1 is
an organic photoreceptor (a carrier-generating substance containing as a main component a bisazo compound described in Japanese Patent Application No. 59-108225, a carrier-transporting substance containing at least one of a styryl compound and an amine derivative as a main component, etc.) (a positively charging photoreceptor), development is performed using a two-component developer, the speed of the cleaning blade 8 relative to the circumferential surface of the photoreceptor drum 1 is 142 m/sec, and the contact angle with the photoreceptor drum 1 is θ was set to 20 @, and F was set to 15 g/cs.

Under these conditions, the thickness h of the cleaning blade is 5
0μm and the free end length l is 1.5fi, and the cleaning blade thickness h is 200μm and the free end length l is 1O.
More than 20,000 copies were made for each case, and the cleaning blade 8 could always be brought into uniform contact with the surface of the photoreceptor drum 1 in cooperation with the biasing force of the spring 13. The surface could be cleaned well.

Furthermore, using the apparatus shown in FIG. 4, the cleaning characteristics were evaluated by varying the contact angle of the thin plate blade with the surface of the photoreceptor drum.

As an experimental method, the thickness h of the blade, the free end length l, and the contact angle θ with the photoreceptor drum were varied, and the results shown in the table below were obtained.

In addition, in the table below, the O mark indicates that there is no toner slippage between the photoreceptor drum and no vibration (squeal).
Therefore, when good results can be obtained, the Δ mark indicates that toner slips through and vibrations occur, and the X mark indicates that toner slips through and vibrations occur. In this case, the - mark indicates that the experiment was not conducted.

The results shown in the above table were obtained using an organic photoreceptor and a two-component development method using U-m+x 1600 Modified i (manufactured by Konishiroku Photo Industry Co., Ltd.). Furthermore, the results were almost the same in the case of the selenium photoreceptor.

The one shown in FIG. 5 is a modification of the one shown in FIG. 4, and has a structure in which the biasing member 13 of the one shown in FIG. 4 is removed. Even if it is, it can fully perform its function.

Furthermore, in this embodiment, the length of the blade 8 (in the drawing, the length in the direction perpendicular to the paper surface)
The one using the one around 320fi and the one around 340m are used.

〔Effect of the invention〕

By configuring the invention as described above, the tip of the cleaning blade can be brought into uniform contact with the tip of the cleaning blade under a low load, and sufficient leaning performance can be maintained, thus reducing the friction at the tip of the cleaning blade. It has increased durability, can maintain good cleaning performance over a long period of time, can be made smaller and cheaper as a whole, and is easy to install because the free end length of the cleaning blade is long. It has excellent effects such as:

[Brief explanation of drawings]

FIG. 1 is a schematic layout diagram showing a cleaning device according to the present invention, FIG. 2 is an enlarged view showing the main parts of the device shown in FIG. 1, and FIG. 4 is a schematic layout diagram showing a cleaning device according to the present invention from which other experiments were conducted, FIG. 5 is a schematic layout diagram showing the cleaning device with the biasing member removed, and FIG. An enlarged view showing the contact portion with the photoreceptor drum, FIG. 7 is a schematic view showing the contact state of the conventional cleaning blade with the photoreceptor drum, and FIGS. It is a figure which shows the case where a contact angle is large and the case where it is small, respectively. 1.20... Photosensitive drum 2... Casing 3... Toner conveying screw 4.15... Guide roller 5... Support frame 6.13... Spring 7.12... Support member 8.21... Cleaning blade (thin blade) 10... Toner guide plate 11... . . . Toner scraping member 16 . . . Scraping base 22 . . . Toner Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (4)

[Claims] (1) A cleaning device that removes residual toner on the surface of an image bearing member by pressing the tip of a cleaning blade into contact with the residual toner, the cleaning blade being constituted by a thin plate blade, and the residual toner remaining on the surface of the image bearing member being The thin plate blade is arranged to be inclined toward the cleaning side, and when the angle between the thin plate blade and the tangent to the image carrier at the point of contact with the image carrier is θ, θ≦30°. A cleaning device with special features. (2) The cleaning device according to claim 1, wherein the thin plate blade is disposed on a support member that is biased by a biasing member. (3) The cleaning device according to claims 1 and 2, wherein the thin plate blade is made of resin. (4) If the thickness of the thin plate blade is h and the free end length is l, then 10≦l/h≦60, and 50 μm≦h
The cleaning device according to any one of claims 1 to 3, wherein the thickness is ≦300 μm.