JPH0228687A - Cleaning device of image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that utilizes an electrostatic transfer process, such as an electrostatic copying machine or a printer, and particularly to a cleaning device for the same. .

(Prior art and problems to be solved) In a well-known image forming apparatus that repeats the process of electrostatically transferring a toner image electrostatically formed on the surface of an image carrier onto a sheet-like transfer material such as paper. It is necessary to sufficiently remove residual toner that remains untransferred on the image carrier during transfer.

Various types of cleaning means have been proposed for this purpose, but at present, urethane cleaning methods have been proposed because they have a simple and compact structure, are advantageous in terms of cost, and have an excellent toner removal function. It is well known that cleaning blades made of elastic materials such as

In this type of cleaning means, if the friction between the cleaning blade and the surface of the image carrier with which it is in pressure contact is too large, the surface of the image carrier may be damaged or the toner may be fused to the surface. This may cause the blade edges to curl up, especially from both ends of the blade, resulting in poor cleaning, or due to static electricity caused by friction.
Various problems occur, such as not being able to obtain a uniform surface potential in the charging step in the next image forming step, which may result in deterioration of image quality such as image unevenness and fogging.

These drawbacks can be avoided to some extent by weakening the pressure force of the blade against the image carrier, but this will reduce the cleaning action itself, resulting in poor cleaning and filming. occurrence cannot be avoided.

The above-mentioned problem when using a cleaning blade is caused by an image forming apparatus that uses a rotating cylindrical image bearing member, which is the most commonly used image bearing member, especially when the number of images per copy is reduced. This is noticeable in color image forming apparatuses in which the number of rotations of the carrier is high.

In order to avoid such problems, it has been proposed to mix a lubricant such as wax into the developer in order to reduce the friction between the image bearing member and the cleaning blade. In some cases, the image quality may be deteriorated due to a decrease in image quality or filming in which a thin film of toner is formed on the surface of the image carrier.

In addition, when installing an image forming apparatus or replacing an image carrier, when there is no toner on the surface of the image carrier and the friction with the blade is large, a service person may apply several I
Although it has been attempted to apply lubricating powder such as polyvinylidene fluoride or PTFB to a thickness of about L11, this is not preferable because the work is complicated and the surface of the image carrier may be damaged.

Furthermore, a toner layer is formed at the time of installation of the device or between the image areas of the image carrier and used as a lubricant, but in this case,
Since there is inevitably a portion where the toner layer is not formed, the friction in this portion is large and there is no fundamental solution.

The present invention has been made in view of the above-mentioned current situation, and is an apparatus that prevents the blade from turning over, especially in non-image areas, in a cleaning device that uses a cleaning blade, and can always perform good cleaning. The purpose is to provide the following.

(2) Effects of the invention (technical means for solving the problems and their effects) In order to achieve the above object, the present invention provides a cleaning device for an image forming apparatus equipped with an elastic cleaning blade that comes into contact with an image bearing member. A thin sheet made of a material having a coefficient of friction against the image carrier that is smaller than that of the cleaning blade is disposed at least near the end of the edge of the cleaning blade that contacts the image carrier. It is characterized by this.

With this configuration, it is possible to prevent blade curling, poor cleaning, filming, etc., particularly at both ends of the cleaning blade, and to always perform good cleaning.

(Description of Embodiments) FIG. 2 is a side view schematically showing the configuration of a color copying machine equipped with a cleaning device to which the present invention is applied (although, of course, this is not limited to color copying machines). Around the cylindrical photoreceptor 1, which has an axis perpendicular to the plane of the paper and rotates in the direction of arrow A, there are a pre-exposure 2, a primary charger 3 for uniformly charging the surface of the photoreceptor, and an electrostatic latent. It is assumed that an exposure section 4 for forming an image is provided, and a latent image for each color separated by these is formed.

The developing device 5 includes a developing device 5Y containing yellow toner.
, a developing device 5M containing magenta toner, a developing device 5C containing cyan toner, and a developing device 5B containing black toner are arranged, and as is well known, the color formed on the photoreceptor is In the case shown in Fig. 6, one of the developing units comes to a developing position close to the photoconductor to perform development corresponding to a color-separated latent image in response to another latent image. device is in its working position.

The developed color image is transferred to the transfer material P supported by the transfer drum 6 by the action of the transfer charger 7, and images of each color are sequentially superimposed to form a color image, and then separated from the transfer drum 6 by the separating claw 9. It is assumed that the image is separated and conveyed to a fixing site (not shown).

Development by the developing device is performed four times as described above, and the cleaning device 8 removes the residual toner remaining on the photoreceptor each time.

The cleaning device 8 includes a cleaning blade 8a made of an elastic material such as urethane rubber so that one edge of the cleaning blade 8a is in pressure contact with the photoconductor l in the longitudinal direction.
is provided to scrape off residual toner.

FIG. 1 is a perspective view showing only the cleaning blade portion of the cleaning device, which consists of a holding member 10 made of a rigid material, and a blade member 11 made of an elastic material such as polyurethane attached to the holding member 10. It is assumed that the edge C of the blade member 11 comes into pressure contact with the surface of an image carrier (not shown) while being held in a proper position in the cleaning device by the holding member 10.

Since the length of the blade member 1 is greater than the maximum image area, non-image areas a, a' always exist at both ends of the bleed member.

As shown, in this non-image area a, a', a thin sea) 1
2.12 is disposed so as to cover the edge C of the blade 11 that presses against the image carrier.

This sheet 12 is made of Arflex Film (trade name:
#6 manufactured by Asahi Glass, thickness 6gm) was formed into a band shape with a width of 9cm, and after making creases in advance, this was formed into a blade edge C (the radius of curvature of this edge is approximately 10gm).
Accordingly, the ends of the sheet 12 are heat-sealed and attached, and are not bonded to the blade edge C.

With this configuration, the non-image area a.

The coefficient of friction at a is much lower than that at the edges of other polyurethanes.

Therefore, as mentioned above, when measures are taken to apply lubricant to the surface of the image carrier or toner between image areas when the image carrier is first installed, or after that, the image carrier may be damaged by the previous operation cycle. In any case, since toner is attached to the image carrier in the image area, this acts as a lubricant, and in the non-image area, due to the friction-reducing effect of the sheet 12, The frictional stress between the blade and the image carrier can be reduced without reducing the pressing action of the blade on the image carrier pair, and it is possible to prevent the blade from turning over and damaging the image carrier surface.

When using the above-mentioned sheet, the blade penetration amount is 0.4 rara and the peripheral speed of the image carrier is 160 m under normal temperature and normal humidity environment.
After passing 3,000 to 4,000 sheets at a speed of 3,000 to 4,000 sheets, the sheet 12 is torn at the part that is in contact with the blurring edge C.
After that, although the edge was exposed, it was confirmed that the leaning was performed well without any occurrence of blade curling.

In this case, the toner used has a number average particle size of 8.0 to 9.5.
gm, volume average particle size of 12 to 13.5 gm.

The sheets attached to the edges of both ends of the blade are not limited to the ones mentioned above, but it has been found that almost the same effect can be achieved by using KF Film #6, 6 mm thick, manufactured by Kureha Chemical Industry Co., Ltd. .

(3) As described in detail, according to the present invention, in a cleaning device using a cleaning blade, it is possible to positionally change the coefficient of friction between the blade edge and the image carrier with an extremely simple configuration. Therefore, it is possible to prevent the occurrence of blade curling, poor cleaning, and filming, especially at the end of the blade, and achieve good leaning.

In particular, since the thin sheet that is the anti-friction member naturally tears after passing a suitable number of sheets and the blade becomes normal after that, the cleaning function can be achieved by applying the present invention at the time of installation of the image forming apparatus, and the cleaning function can be improved thereafter. It has a significant effect on maintenance.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing the configuration of an image forming apparatus suitable for applying the present invention, and FIG. 2 is a perspective view of a cleaning blade showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Photoreceptor, 5...Developing device, 6...Transfer drum, 10--Cleaning blade. 8a. 1st lean neck flade, 11...Blade member, 12.O. Sheet. The procedural amendment was filed in December 1986 (Q Japan Patent Office Commissioner Yoshi 1) Moon Takeshi (1) Indication of the case Patent Application No. 178030 (1983) Name of the invention Image forming device cleaning device (3) ) Relationship with the case of the person making the amendment Applicant's address name Canon Co., Ltd. (4) Number of inventions increased by agent's amendment O Subject of amendment Drawings and description

Claims (3)

[Claims] (1) In a cleaning device for an image forming apparatus equipped with an elastic cleaning blade that contacts an image carrier, at least near the end of the edge of the cleaning blade that contacts the image carrier, there is a A cleaning device equipped with a thin sheet made of a material with a coefficient of friction smaller than that of the cleaning blade. (2) The cleaning device according to claim 1, wherein the thickness of the sheet is set to such an extent that the blade edge directly contacts the surface of the image carrier when the sheet is broken after passing a predetermined number of sheets. (3) The cleaning device according to claim 1, wherein the thickness of the sheet is smaller than either the number average particle size or the volume average particle size of the toner to be cleaned.