JPH0312317B2 - - 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 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 sheet of paper g using a toner transfer charger f. At the same time as transferring, this paper g is peeled off from the photoreceptor 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 the remaining toner may contain toner of opposite polarity. Since it has the disadvantage that it cannot be removed, blade-type cleaning devices that do not have the above-mentioned disadvantage are generally 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. As a result, the tip of the blade m is worn out, resulting in a significant reduction in cleaning costs. 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 degrading the copy image, or causing damage to the surface of the photoreceptor a. Since the carrier and paper powder that adheres and is conveyed easily enter the gap between the blade m and the photoreceptor a, there is a drawback that the surface of the photoreceptor a is damaged by the carrier and the blade m. Ta. If this happens, residual toner etc. will get stuck in the scratches on the surface of the photoconductor a, causing surface conduction and causing the photoconductor a.
The charge may no longer be applied to a part of the paper g, or the clogged toner may be partially transferred to the paper g, causing white spots or black spots to appear on the copied image, resulting in deterioration of the copied image. This had the disadvantage of further increasing the amount. 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. [Means and effects for solving the problems] The present invention has been made in view of the above, and is based on a blade-type cleaning device. The blade contains polyvinylidene fluoride, which has an anti-friction effect, and contains silicon dioxide, which is an abrasive, to remove scratches, etc. that occur on the surface of the photoreceptor, thereby providing a cleaning device that does not have the above-mentioned drawbacks. It's about doing. [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. Assuming that the cleaning device is used in an electrophotographic device for scraping and removal, the cleaning blade is made of 20 to 50 parts by weight of polyvinylidene fluoride with a particle size of 0.1 μm to 1.0 μm and a particle size of 0.01 μm.
It is characterized in that it is made of a polyurethane resin to which 10 to 60 parts by weight of silicon oxide with a diameter of 1.0 μm to 1.0 μm is added. When polyvinylidene fluoride is used with a particle size of 1.0 μm or more, it tends to deteriorate the abrasion resistance of the cleaning blade, whereas when used with a particle size of 0.1 μm or less, it is inconvenient to handle. Uniform dispersion into the resin becomes difficult, so as mentioned above, if the particle size is 0.1 μm or more,
A value in the 1.0 μm range is preferable. Furthermore, if the amount added is less than 20 parts by weight, it is insufficient to lower the frictional resistance and has no effect on the above-mentioned stick slip phenomenon, and if it is added more than 50 parts by weight, it becomes difficult to knead with the polyurethane resin. Therefore, the amount added is preferably in the range of 20 parts by weight to 50 parts by weight. On the other hand, if a silicon oxide base is used with a particle size of 1.0 μm or more, the cleaning blade is likely to wear out, similar to the polyvinylidene fluoride mentioned above, and if a silicon oxide base is used with a particle size of 0.01 μm or less, it becomes inconvenient to handle. Therefore, it is preferable to have a thickness in the range of 0.01 μm to 1.0 μm. Further, as with the polyvinylidene fluoride, the amount added is preferably in the range of 10 parts by weight to 60 parts by weight for reasons of its addition effect and dispersibility. [Function] According to the above-mentioned technical means, the cleaning blade is made of 20 to 50 parts by weight of polyvinylidene fluoride with grain size of 0.1 μm to 1.0 μm, and
Since it is made of polyurethane resin to which 10 to 60 parts by weight of silicon oxide of 0.01 μm to 1.0 μm is added, the cleaning blade and the surface of the photoreceptor are bonded by the lubricating action of this polyvinylidene fluoride and the abrasive agent of silicon oxide. In addition to significantly reducing the frictional resistance of the photoreceptor, it is also possible to remove scratches and the like on 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 a polyurethane resin as a base material, polyvinylidene fluoride as a lubricant, and silicon oxide as an abrasive. In other words, the product name: Cyanaprene A- (polyurethane manufactured by Nippon Cyanamid Co., Ltd.), 30 parts by weight of vinylidene polyfluoride, and the product name: Aerosil R-972.
(Fume strip silicon oxide manufactured by Nippon Aerosil Co., Ltd.)
After adding 20 parts by weight and 0.05 parts by weight of an antifoaming agent and thoroughly defoaming in a vacuum, add a crosslinking agent heated to about 120℃ and defoaming in a vacuum. Inject into the mold. Next, primary vulcanization was performed at 100°C for 80 to 90 minutes, and after being removed from the mold, 100°C,
Secondary vulcanization is performed for 24 hours, and then heat-formed at room temperature for one day or more to produce a cleaning blade made of a cured urethane product with a JISA hardness of 74°. 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 to 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. Then, using the cleaning device of the present invention, a cleaning device in which other additives are added to the cleaning blade, and a conventional cleaning device in which no additives are added to the cleaning blade, the cleaning blade and photosensitive drum surface in each device are cleaned. The following comparative experiment was conducted in order to compare the degree of friction and the presence or absence of black spots on the copied images. That is, after cleaning the photosensitive drum surface of each device with isopropyl alcohol to remove toner, paper dust, etc. adhering to the surface, the photosensitive drum is rotated to directly connect the surface with the cleaning blade.
The cleaning devices 1 to 1 containing the cleaning device of the present invention and other additives were examined for the occurrence of partial curling of each cleaning blade and stick slip phenomenon due to the frictional effect of continuous contact for a period of time. Regarding No. 5, 40,000 copies were actually made continuously using each of these devices, and it was investigated whether white spots, black spots, etc. occurred in the copied images. As a result, the results shown in Table 1 below were obtained.

【table】

〔Effect of the invention〕

According to the present invention, since the cleaning blade is made of a polyurethane resin to which specific amounts of polyvinylidene fluoride and silicon oxide of a specific particle size are added, the lubricating action of the polyvinylidene fluoride and the abrasive action of the silicon oxide are effective. It is possible to significantly reduce the frictional resistance between the cleaning blade and the surface of the photoreceptor, and to remove scratches and the like on the surface of the photoreceptor. Therefore, it is possible to effectively prevent wear or deformation of the cleaning blade and dramatically extend its life, maintain the initial cleaning effect over a long period of time, and prevent white spots, black spots, etc. that appear on copied images. It has the effect of preventing

[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
It is characterized by being composed of a polyurethane resin to which 20 to 50 parts by weight of polyvinylidene fluoride with a particle size of 0.1 μm to 1.0 μm and 10 to 60 parts by weight of silicon oxide with a particle size of 0.01 μm to 1.0 μm are added. cleaning equipment.