JPH04245285A - Cleaning device - Google Patents

Abstract

PURPOSE:To prevent the blade ripping caused by the friction between a photoreceptor drum and a cleaning blade and the defective cleaning due to the damage of the blade. CONSTITUTION:A coating layer 18 containing sliding grains is provided at a contact section of a scooping sheet 15 in contact with a photoreceptor 1 provided on the upstream side of a cleaning blade 3 in the moving direction of the photoreceptor 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for image forming apparatuses such as electrophotographic copying machines and printers.

0002

[Prior Art] An electrostatic latent image formed on the surface of a moving image carrier is developed as a toner image by a developing means, and after this toner image is transferred, it remains on the surface of the image carrier without contributing to the transfer. Image forming apparatuses that repeat the process of cleaning toner are conventionally well known.

In this type of image forming apparatus, a cleaning blade made of an elastic material such as urethane rubber is used to remove residual toner because it has a simple structure, is small, and is advantageous in terms of cost. , has been widely used as a means for cleaning residual toner.

As is well known, in a cleaning means using a cleaning blade, a large amount of friction is generated between the blade edge and the image carrier in order to press the edge of the blade into contact with the image carrier. However, as mentioned above, there is some residual toner in the image area on the surface of the image carrier, so although the cleaning blade originally has the effect of scraping off this toner, it has the effect of scraping off this toner. The presence of the lubricant acts as a lubricant at the contact portion between the image carrier surface and the blade edge, and the desired relative positional relationship is maintained between the two to perform the toner removal action.

However, even if the above measures are taken, under certain conditions, for example when an original with extremely low image density is continuously copied, the supply of toner that provides a lubricating effect between the blade and the image carrier may become insufficient. was blocked, the coefficient of friction became extremely large, the tip of the cleaning blade was turned around along the rotational direction of the recording medium (so-called blade turning), and the tip edge was partially damaged.

As a means to solve this problem, as shown in FIG. 5, a residual toner storage member 14 is disposed upstream of the cleaning blade in the image carrier traveling direction, and the cleaning blade collects residual toner from the surface of the image carrier. There is a method of keeping the toner constantly in contact with the surface of the image carrier by storing the removed toner between the residual toner storage member and the image carrier.

[0007] Furthermore, there is a method for reducing the initial frictional force by applying fluororesin powder such as PTFE (polytetrafluoroethylene) or PVDF (polyvinylidene fluoride) to the contact portion of the tip of the cleaning blade with the photosensitive drum. are being taught.

[0008]

[Problem to be Solved by the Invention] However, even with the former configuration, when originals with extremely low image density are successively copied, the amount of toner stored is small, so the tip of the blade may turn over or the portion may become uneven. Damage to the leading edge may occur. Even in the latter configuration, if the fluororesin powder disappears from the surface of the cleaning blade during long-term durability, etc., there is a problem that the frictional force between the cleaning blade 3 and the photosensitive drum 1 ends up increasing. In particular, near both ends of the cleaning blade that are in contact with the image carrier outside the image forming area, the friction between the image carrier and the cleaning blade becomes larger, acting as a brake on the moving image carrier. As a result, the running of the image carrier becomes unstable,
There has been a problem in that the tip of the cleaning blade vibrates or turns over, making it impossible to maintain a good cleaning effect.

[0009]

[Means for Solving the Problems] The present invention solves the above problems, and includes a cleaning blade for removing toner remaining on a moving image bearing member, and an upstream side of the cleaning blade in the moving direction of the image bearing member. A cleaning device having a sheet member provided in contact with the surface of the image carrier on the side thereof, the portion of the sheet member in contact with the surface of the image carrier is provided with a coating layer containing slippery particles. It is characterized by this.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic diagram of an image forming apparatus to which the present invention can be applied, in which a cleaning device 2 as a cleaning means is provided in contact with a photosensitive drum 1 as an image carrier rotating in the direction of arrow A. A cleaning blade 3 of this cleaning device 2 is in pressure contact with the surface of the photosensitive drum 1. Further, in the vicinity of the photosensitive drum 1, a pre-exposure light source 4, a primary charger 5, a developing device 7, a transfer charger 10, and a separation charger 11, which are components of the electrophotographic recording process, are arranged. After the surface charge of the photosensitive drum 1 is removed by the step 4, the photosensitive drum 1 is uniformly charged by the primary charger 5, the photosensitive drum 1 is exposed to light in the area 6, and then a toner image is formed on the surface of the photosensitive drum by the developing device 7. form. after that,
The toner image formed on the surface of the photosensitive drum 1 is transferred by a transfer charger 10 onto a transfer material 8 that has passed through a path 9, and this transfer material 8 is transferred to the photosensitive drum while carrying the toner image by a separation charger 11. 1, and is conveyed by the conveying means 12 to a fixing means (not shown).

On the other hand, residual toner 13 remaining on the surface of the photosensitive drum 1 without contributing to the transfer at the transfer site reaches the cleaning device 2, where it is scraped off from the surface of the photosensitive drum 1 onto the scraping sheet 15 by the cleaning blade 3. Thereafter, the residual toner 13 scraped off by the cleaning blade 3 is conveyed to a waste toner container (not shown) by a toner conveying screw 16 provided in the cleaning device 2.

By the way, as mentioned above, the photosensitive drum 1
Since toner 13 as a lubricant is not always present on both ends of the cleaning blade that contacts the photosensitive drum 1 outside the width of the image area on the surface (length in the direction perpendicular to the plane of the paper), the cleaning blade 3 Since the frictional force between both ends of the cleaning blade 3 and the photosensitive drum 1 increases, problems such as vibration and bending of the tip of the blade tend to occur in these end areas of the cleaning blade 3. In addition, conventionally, urethane rubber has been mainly used as the material for the cleaning blade 3 due to its chemical resistance, abrasion resistance, moldability, and mechanical strength. For example, since the frictional force against the OPC photosensitive drum whose surface layer is made of a polymer resin such as polycarbonate is extremely high, in the case of such a combination, the image forming area where the toner 13 as a lubricant is not present is particularly important. Vibration and curling of the blade tip at the end of the outer cleaning blade 3 is likely to occur.

Next, an embodiment of the present invention that solves the above problem will be described.

FIG. 2 is a diagram showing a cleaning device according to a first embodiment of the present invention, in which the cleaning blade 3 is
A coating layer 18 is provided on the photosensitive drum abutting portion of the scraper sheet 15 provided in contact with the photosensitive drum on the upstream side of the cleaning blade 3 and the photosensitive drum 1 by attaching this coating material to the surface of the photosensitive drum. It becomes possible to reduce the frictional force both at the initial stage and during durability.

The sheet member 15 used here must not mechanically damage the surface of the photosensitive drum, so it is made of high-quality material such as a polyurethane sheet or a PET (polyethylene terephthalate) sheet. A molecular resin film sheet is preferable, and the coating layer 18 provided on the contact portion of the scraping sheet 15 with the photosensitive drum 1 is a coating layer in which lubricating particles are dispersed in a binder resin. Then, the coating layer 18 provided on the scraper sheet 15 is brought into contact with the surface of the photosensitive drum, and as the photosensitive drum rotates in the direction of arrow A, the coating layer 18 is rubbed, and the coating material is scraped at that time. Powder adheres to the surface of the photosensitive drum, and this adhered part is removed by the cleaning blade 3.
By reaching , the frictional force between the cleaning blade 3 and the photosensitive drum is reduced, and the lubrication effect can be promoted.

Furthermore, as the lubricating particles used in this example, those generally known as solid lubricants such as inorganic substances and organic substances can be used. Examples of inorganic substances include talc, organic substances, etc.
Calcium carbonate, molybdenum disulfide, silicon dioxide, graphite, etc. are listed, and organic substances include fluororesin,
Examples include nylon resin (polyamide), silicone resin, polyacetal resin, etc. Among these, fluorine-based compounds are particularly preferred, regardless of whether they are organic or inorganic substances, because they have particularly low frictional resistance.

Examples of the fluorine compound powder include fluorinated graphite, polyvinylidene fluoride resin, tetrafluoroethylene resin,
Examples include tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin, trifluorochloride ethylene resin, and tetrafluoroethylene-ethylene copolymer resin.

Another condition desired for the slippery particles is that the coating layer formed on the surface of the sheet main body has a high adhesion to the binder resin. Therefore, in order to satisfy this condition, irregularly shaped particles are more preferable than spherical particles. This is because if the shape is irregular, in addition to the adhesion force with the binder resin, a mechanical adhesion force due to the anchor effect is applied, making it difficult for the lubricant particles to separate from the coating layer.

Considering these facts, it is particularly preferable that the lubricating particles be fluorinated graphite, which is a scale-like crystal, has an irregular shape, and has a low coefficient of friction. Examples of fluorinated graphite include Cefbon DM (manufactured by Central Glass Co., Ltd.) which is (C2F)n type, Cefbon CMA which is (CF)n type, Cefbon CMF (manufactured by Central Glass Co., Ltd.), and fluorocarbon #206.
5, #1030, #1000 (manufactured by Asahi Glass Co., Ltd.), CF-1
00 (Nippon Carbon), and (CF) n-type fluorinated carbon #2028 and #2010 (manufactured by Asahi Glass Co., Ltd.), as well as the above fluorinated graphite treated with a base such as amine to reduce fluorine on the surface. Examples include, but are not limited to, those obtained by removing .

The average particle diameter of the slippery particles is preferably 10 microns or less in order not to impair toner cleaning.

[0022] The binder resin used in this example is as follows:
Any resin that is generally used as a coating agent may be used, but a resin with a low coefficient of friction is particularly preferable since it is formed as a coating layer on the surface of the sheet body and used in pressure contact with an image carrier. Examples of such binder resins include nylon resin (polyamide), silicone resin, polyacetal resin, and fluororesin.

Another condition desired for the binder resin is that it should be able to follow the surface shape of the image carrier without interfering with the elastic deformation of the sheet main body.

[0024] Still other conditions are that the adhesiveness with the sheet body is good and that the dispersibility with the slippery particles is good.

Considering these points, it is preferable to use a coating agent made of nylon resin material as the binder resin. This coating agent has good dispersibility with the above-mentioned fluorinated graphite.

[0026] This coating agent is preferably soluble in a solvent from the viewpoint of ease of production, and commercially available ones include Platamide M1276, M995 (manufactured by Plate Bonn), and CM4000 (manufactured by Toray Industries). Alternatively, crosslinkable Toresin F30, MF30, EF30T (
(manufactured by Teikoku Kagaku Sangyo Co., Ltd.), but is not limited thereto.

The film thickness of the coating layer containing the lubricating particles and binder resin in this example was determined to be 1, taking into consideration the influence on the elastic deformation of the sheet body, durability, adhesion, and other various conditions.
It is preferably about 100 μm, more preferably 5 to 30 μm.

[0028] When manufacturing the scoop sheet of this example,
Fluorinated graphite powder is dispersed in a nylon resin solution dissolved in a solvent such as alcohol, and then the solution is brushed and coated with a coater bar or the like on a scraper sheet 15 made of a polyurethane sheet that has been adhered to a sheet metal in advance. Alternatively, the thickness can be controlled to any desired thickness by dipping. In this case, any solvent may be used as long as it dissolves the nylon resin and uniformly disperses the fluorine compound.

Incidentally, the present inventors coated a scraper sheet made of a polyurethane sheet with the recipe shown below, and applied a cleaning blade 3 made of polyurethane rubber to an OPC photosensitive drum whose surface layer was made of polycarbonate. When cleaning was performed by bringing the cleaning blade into contact with the drum, the frictional force between the cleaning blade and the photosensitive drum could be reduced both initially and during durability.
The tip of the cleaning blade did not vibrate or turn over, and a stable cleaning action was always maintained.

- Binder resin coating agent Platamide M995 (manufactured by Prate Bon) - Lubricating particles Cefbon-DM (fluorinated graphite)

[0031] The tip of the polyurethane sheet of Sukui Sheet was coated by dipping with a solution prepared by dissolving 10 parts by weight of Platamide in 100 parts by weight of methyl alcohol and uniformly dispersing 50 parts by weight of fluorinated graphite, and after natural drying.
A coating layer 23 was formed by heating and drying at 30° C. for 10 minutes. Cut this polyurethane sheet to a width of 10 mm and a total length of 24 mm.
A scraping sheet with a thickness of 0 mm and a coating layer thickness of 10 microns was manufactured.

Next, another embodiment of the present invention will be described.

FIG. 3 is a schematic diagram of a cleaning device according to a second embodiment of the present invention, in which members having the same functions as those in the previously described embodiments are designated by the same numbers.

In this embodiment, in order to reduce the frictional force between the cleaning blade 3, which is brought into contact with the photosensitive drum 1 in order to remove the toner 13 remaining on the photosensitive drum 1, and the surface of the photosensitive drum, the photosensitive scraping sheet 15 is removed. A coating layer 18 made of a binder resin in which lubricating particles are dispersed is provided on the drum contact portion, and a coating layer 19 similar to that provided on the toothpick sheet is also provided on the tip of the cleaning blade 3 that contacts the photosensitive drum 1. I am trying to set it up.

That is, as in this embodiment, the frictional force between the cleaning blade 3 and the photosensitive drum 1 is obtained by attaching the slippery particles from the coating layer 18 provided on the scraper sheet 15 to the surface of the photosensitive drum 1. In addition to the effect of reducing the frictional force between the cleaning blade 3 and the photosensitive drum 1, the frictional force between the cleaning blade 3 and the photosensitive drum 1 can be further reduced by providing a coating layer 19 for reducing frictional force on the contact portion of the cleaning blade 3 with the photosensitive drum 1. Not only this, but also the durability of cleaning performance can be further improved.

Here, as for the coating layers 18 and 19 provided on the cleaning blade 3 and the pick sheet 15, the coating layer 18 provided on the pick sheet 15 is gradually worn out due to contact and rubbing with the photosensitive drum 1. Since it is necessary to attach the lubricating particles to the surface of the photosensitive drum, it would be better to increase the amount of dispersion of the lubricating particles and provide a coating layer 18 made of a binder resin having appropriate abrasion resistance. On the other hand, the coating layer 19 provided on the cleaning blade 3 needs to improve its wear resistance even if the amount of dispersion of slippery particles is somewhat reduced.
Further, as the binder resin, it is also necessary to select a binder resin that has excellent wear resistance.

Next, still another embodiment of the present invention will be described.

FIG. 4 is a schematic diagram for explaining a cleaning device according to a third embodiment of the present invention.
In order to reduce the frictional force between the cleaning blade 3 and the surface of the photosensitive drum, which is brought into contact with the cleaning blade 3, a coating layer 18 made of a binder resin in which lubricating particles are dispersed is provided on the photosensitive drum contact portion of the scraper sheet 15, and the cleaning blade 3 is A similar coating layer 20 is also provided on the toner storage member 14 disposed upstream of the photosensitive drum 1 in No. 3 in the traveling direction.

As in this embodiment, the residual toner 1 accumulated between the toner storage member 14 and the photosensitive drum 1
The coating layer 2 provided on the toner storage member 14 is removed when the toner storage member 3 circulates in the region S as the photosensitive drum 1 travels.
The lubricating particles dispersed in the coating layer 20 are dispersed and diffused into the residual toner 13 in the area S, thereby adhering to the surface of the photosensitive drum, and the cleaning blade 3 and the photosensitive drum 1 are bonded together. This makes it possible to further reduce frictional force.

[0040]

As explained above, the present invention includes a cleaning blade that comes into contact with the image carrier and removes the remaining toner, and a cleaning blade that scoops up the residual toner scraped off from the image carrier. In a cleaning device having a scraping sheet for receiving an image, a coating layer containing slippery particles is provided on the contact portion of the scraper sheet with the image carrier, and the slippery particles are attached to the surface of the image carrier, thereby making it possible to remove the cleaning blade and the image. By reducing the frictional force with the carrier, the tip of the cleaning blade does not vibrate or turn over even during the initial stage and during durability, and has the effect of always maintaining a stable cleaning action.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an image forming apparatus to which the present invention can be applied.

FIG. 2 is a diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a third embodiment of the present invention.

FIG. 5 is a schematic diagram showing a conventional cleaning device.

[Explanation of symbols]

1 Photosensitive drum 2 Cleaning device 3 Cleaning blade 4 Pre-exposure light source 5 Primary charger 6. Light image exposure section 7 Developing device 8 Transfer material 9 Passage 10 Transfer charger 11 Separation charger 12 Transport means 13 Residual toner 14 Residual toner storage member 15 Squish sheet 16　Discharge toner conveyance screw 17 Coating layer 18 Coating layer 19 Coating layer 20 Coating layer

Claims (3)

[Claims] 1. A cleaning blade for removing toner remaining on a moving image carrier; and a sheet member provided in contact with the surface of the image carrier upstream of the cleaning blade in the moving direction of the image carrier. A cleaning device comprising: a coating layer containing slippery particles is provided on a portion of the sheet member that comes into contact with the surface of the image carrier. 2. The cleaning device according to claim 1, wherein the coating layer is made of a binder resin in which lubricating particles are dispersed. 3. The cleaning device according to claim 1, wherein the coating layer is comprised of a resin layer in which fluorinated graphite particles are dispersed as slippery particles.