JPH0312316B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a cleaning device for an electrophotographic apparatus that removes toner remaining on the surface of a photoreceptor, and particularly to a cleaning device that uses a cleaning blade to remove the toner. [Prior Art] Conventionally, in an electrophotographic copying machine as an example of an electrophotographic apparatus, as shown in FIG. An electrostatic latent image is formed on the surface using an optical system c, and this latent image is developed with toner using a developing device d to form a toner image e. This toner image e is then transferred onto a paper g by a toner transfer charger f. At the same time, this paper g is peeled off from the photosensitive belt a by a paper peeling charger h, and the toner is fixed by a fixing device i to obtain a copy. On the other hand, the photoreceptor a after the paper g is peeled off
The static electricity is removed by a static electricity removal charger j as necessary,
Further, the toner remaining on the surface thereof is removed by a cleaning device k, and it is configured to be reused. By the way, the fur brush method, the magnetic brush method, and the blade method are conventionally known as the above-mentioned cleaning device.However, the above-mentioned fur brush method has a structure in which the removed toner scatters, so it does not require an absorption mechanism or an over-structured structure. However, the magnetic brush method also requires a separate expensive cleaning sleeve to accommodate the magnet, and if the residual toner contains toner of opposite polarity, it is difficult to remove it. Generally, blade-type cleaning devices that do not have the above-mentioned drawbacks are widely used. That is, as shown in FIG. 3, this device includes a cleaning box l provided near the photoreceptor a along its length, and with a portion facing the photoreceptor a open; It consists of a cleaning blade m installed in a box l and whose tip is attached in pressure contact with the surface of the photoreceptor a, and the cleaning blade m scrapes off toner remaining on the surface of the photoreceptor a for cleaning. The structure is simple, compact, and
It is widely used because of its low cost and low power consumption. [Problems to be Solved by the Invention] However, in the cleaning device using the cleaning blade m, since the tip of the blade m is always in contact with the surface of the photoreceptor a, friction with the surface of the photoreceptor a is caused. Due to this action, the tip of the blade m is worn out, resulting in a disadvantage that the cleaning effect is significantly reduced. In particular, when a document with a pattern in which black image lines and non-image lines in the margin are regularly repeated, such as a computer output document, is continuously copied, a portion of the photoreceptor a and the blade m Since the blades are in direct contact with each other for a long time without intervening the residual toner, the frictional effect increases, and as a result, the blade m may warp and turn over, or vibrate due to the stick slip phenomenon. There were cases where the cleaning blade m was partially turned over and deformed. If such uneven wear or deformation of the cleaning blade m progresses, a ghost image or streaks may appear on the copy paper, significantly deteriorating the copy image, or the blade m may damage the photoreceptor a.
This may cause damage to the surface or even cause peeling of the photoconductive layer. Furthermore, the carrier and paper powder adhering to the surface of the photoreceptor a and being conveyed are removed from the blade m.
This tends to get into the gap between the photoreceptor a and the photoreceptor a, which has the disadvantage of further aggravating the above-mentioned drawbacks. Therefore, in the blade-type cleaning device, it is necessary to replace the cleaning blade m every time approximately 40,000 to 60,000 copies are made, and maintenance thereof is troublesome. The present invention has been made in view of this point of view,
The objective is to reduce the frictional resistance between the cleaning blade and the surface of the photoreceptor, assuming a blade-type cleaning device.
It is an object of the present invention to provide a cleaning device free from the above-mentioned drawbacks by including polyvinylidene fluoride having an anti-friction effect in the cleaning blade. [Means for Solving the Problem] That is, the present invention disposes a cleaning blade near a photoreceptor that rotates in a fixed direction, and presses the tip of the cleaning blade against the surface of the photoreceptor to remove toner remaining on the surface. The cleaning blade is designed to be used as a cleaning device in an electrophotographic device for scraping and removing, and is characterized in that the cleaning blade is made of a polyurethane resin to which 20 to 80 parts by weight of polyvinylidene fluoride with a particle size of 0.1 μm to 1.0 μm is added. That is. Here, if the above-mentioned polyvinylidene fluoride has a particle size of 1.0 μm or more, it tends to deteriorate the wear resistance of the cleaning blade, whereas if a particle size of 0.1 μm or less is used, it is inconvenient to handle, and as mentioned above, Uniform dispersion into the polyurethane resin becomes difficult, so as mentioned above, the particle size is 0.1 μm.
The thickness is preferably in the range of 1.0 μm to 1.0 μm, preferably 0.2 μm to 0.5 μm. Furthermore, if the amount added to the polyurethane resin is less than 20 parts by weight, it is insufficient to lower the frictional resistance and has no effect on the stick slip phenomenon described above;
If more than 1 part by weight is added, the proportion of polyurethane in the cleaning blade will decrease and the wear resistance will decrease, so the amount added should be 20 parts to 80 parts by weight,
A preferable range is 30 parts by weight to 60 parts by weight. According to the above-mentioned technical means, the cleaning blade is made of polyurethane resin to which 20 to 80 parts by weight of polyvinylidene fluoride with a particle size of 0.1 μm to 1.0 μm is added. The lubrication effect of the cleaning blade makes it possible to significantly reduce the frictional resistance between the cleaning blade and the surface of the photoreceptor. [Example] Next, an example of the present invention will be described. As shown in FIG.
It is arranged in the vicinity of the photosensitive drum 1 and consists of a cleaning blade 2 manufactured by the method described below, and a cleaning box 3 that covers the periphery of this blade 2. First, the cleaning blade 2 is obtained by the following manufacturing method and is made of polyurethane resin as a base material and polyvinylidene fluoride as a lubricant. That is, 50 parts by weight of vinylidene polyfluoride and 0.05 parts by weight of an antifoaming agent were added to Cyanaprene A-7 (trade name, polyurethane manufactured by Nippon Cyanamid Co., Ltd.), and after sufficient vacuum defoaming, the mixture was heated to about 120°C. The crosslinking agent prepared above is added and the mixture is degassed under vacuum and then injected into a cleaning blade mold. Next, primary vulcanization was performed at 100°C for 80 to 90 minutes, and after being removed from the mold, 100°C
A cleaning blade is manufactured by performing secondary vulcanization for 24 hours and further heat-forming at room temperature for one day or more. Next, this cleaning blade 2 is attached to a position near the photosensitive drum 1 so that the contact angle θ between its tip and the surface of the photosensitive drum 1 is 5 to 15 degrees, and the cleaning blade 2 is attached at a position near the photosensitive drum 1 such that the contact angle θ between the cleaning blade 2 and the surface of the photosensitive drum 1 is 5° to 15°. ~40g/
The cleaning device of the present invention is constructed by applying a pressure of cm. Using the cleaning device of the present invention, a conventional cleaning device using a cleaning blade to which no additive is added, and a cleaning device using a cleaning blade to which a lubricant other than polyvinylidene fluoride is added, each device can be cleaned. In order to compare the degree of friction between the cleaning blade and the surface of the photosensitive drum, the following comparative experiment was conducted. That is, after cleaning the photosensitive drum surface of each device with isopropyl alcohol to remove toner, paper dust, etc. adhering to the surface, rotate the photosensitive drum and directly connect the surface and cleaning blade with the cleaning blade.
The cleaning blades were kept in continuous contact for a period of time, and the occurrence of partial curling and stick slip phenomena of each cleaning blade due to the frictional action was examined. As a result, the results shown in Table 1 below were obtained.

〔Effect of the invention〕

According to the present invention, since the cleaning blade is made of polyurethane resin to which a specific amount of polyvinylidene fluoride of a specific particle size is added, the frictional resistance between the cleaning blade and the surface of the photoreceptor is reduced by the lubricating action of the polyvinylidene fluoride. It is possible to significantly reduce the amount. Therefore, wear or deformation of the cleaning blade can be effectively prevented and its lifespan can be dramatically extended, so that the initial cleaning effect can be stably maintained over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a cleaning device according to an embodiment of the present invention, FIG. 2 is a diagram illustrating the configuration of a conventional electrophotographic copying machine, and FIG. 3 is a side sectional view of the cleaning device. [Description of symbols], 1...Photosensitive drum, 2...Cleaning blade, 3...Cleaning box.

Claims (1)

[Claims] 1. A cleaning device for an electrophotographic apparatus in which a cleaning blade is disposed near a photoconductor that rotates in a certain direction, and its tip is brought into pressure contact with the surface of the photoconductor to scrape off and remove toner remaining on the surface of the photoconductor. Cleaning blade, particle size
1. A cleaning device comprising a polyurethane resin to which 20 to 80 parts by weight of polyvinylidene fluoride of 0.1 μm to 1.0 μm is added.