JPS6148882A - Cleaning device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To reduce the frictional resistance between a cleaning blade and the surface of a photosensitive body by molding the cleaning blade of polyurethane resin to which specific amounts of polyvinylidene fluoride and silicon oxide of specific particle size are added respectively. CONSTITUTION:The clean device of the electrophotographic copying machine has the cleaning blade nearby a photosensitive body which rotates in one direction and presses its front end against the surface of the photosensitive body to scrape toner remaining on the surface. The cleaning blade is molded of polyurethane resin to which 20-50pts.wt. polyvinylidene of 0.1-1.0mum in particle size and 10-60pts.wt. silicon oxide of 10-1.0mum are added respectively. Consequently, the frictional resitance between the photosensitive body surface and cleaning blade is reduced to prevent the abrasion or deformation of the blade, and a flaw, etc., formed in the surface are removed by polishing the surface, so that stable cleaning effect is maintained for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cleaning device for an electrophotographic copying machine 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. It is related to.

[Conventional technology]

Conventionally, in an electrophotographic copying machine, as shown in FIG. 2, a charger (
b), and forms an electrostatic latent image on this surface using an optical system tc+, and develops this latent image with toner using a developer (dl) to form a toner image (el).
el is transferred onto paper (g) using a toner transfer charger (fl), and this paper (g) is peeled off from the photoreceptor (ar) using a paper peeling charger (hl) and transferred to a fixing device (
The toner is fixed by i) to obtain a copy.

On the other hand, after the paper (g) has been peeled off, the photoreceptor (al) is charged with a charger (k) for removing static electricity, if necessary, and the toner remaining on its surface is removed with a cleaning device (k+). Constructed for reuse.

By the way, the fur brush type, the magnetic brush type, and the blade type are conventionally known as the above-mentioned cleaning devices, but the above-mentioned fur brush type does not require an absorption mechanism or an absorption mechanism because the removed toner scatters due to its structure. The drawback is that a filtration mechanism is required, making the device complicated and large, and the cost is relatively high.On the other hand, the magnetic brush method also requires a separate expensive cleaning sleeve to accommodate the magnet, and the residual toner ζ has the opposite polarity toner. Therefore, blade-type cleaning devices that do not have the above-mentioned drawbacks are widely used.

That is, this device has a photoreceptor (a) as shown in FIG.
A cleaning box (illustrated) is provided along the length of the cleaning box near t and has a part open facing the photoconductor (a), and a cleaning box (phantom) is provided inside this box (R) with its tip open. , a cleaning blade (ml) mounted in pressure contact with the surface of the photoreceptor (a), which performs cleaning by scraping off residual toner on the surface of the photoreceptor (a) between the cleaning blades. It is widely used because it has a simple configuration, is smaller in size, lower in cost, and saves power.

[Problem that the invention seeks to solve]

However, in the cleaning device using this cleaning blade ((6)), since the tip of the blade (between) is always in contact with the surface of the photoreceptor (a),
The blade (
There was a drawback that the tip of the rnl was worn out and the cleaning effect was 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) Since the blade (6) comes into direct contact with the blade (6) for a long period of time without intervening residual toner, the frictional effect increases, and as a result, the blade (6)
The cleaning blade (ml) may become deformed due to the cleaning blade (e) warping and turning over, vibrating due to the stick-slip phenomenon, or turning over partially.

If uneven wear or deformation of the leaning blade progresses in this way, a ghost image or streaks will appear on the copy paper, significantly deteriorating the copied image, or the leaning blade may adhere to the surface of the photoreceptor (a1). The carrier and paper powder conveyed through the blade and the photoreceptor (al
Since the carrier and the blade (m) tend to easily enter the gap between the carrier and the blade (m), there is a drawback that the surface of the photoreceptor (aJ) is damaged.

If this happens, residual toner etc. will get stuck in the scratches on the surface of the photoconductor (a), causing creeping conduction and causing a part of the photoconductor (al) to become uncharged, or the clogged toner will partially spread onto the paper. (The transfer to the glazing layer causes white spots and black spots to appear in the copied image, which has the disadvantage of further increasing the deterioration of the copied image.

Therefore, in the blade-type cleaning device, it is necessary to replace the cleaning blade ((6)) every time approximately 40,000 to 60,000 copies are made, which has the disadvantage of tedious maintenance. .

[Means and effects for solving the problems] The present invention has been made in view of the above points, and is based on a blade-type cleaning device. The cleaning blade contains polyvinylidene fluoride, which has an anti-friction effect, and silicon dioxide, which is an abrasive, to remove scratches, etc. that occur on the surface of the photoreceptor, thereby providing an electrophotographic copying machine free from the above-mentioned defects. The purpose of the present invention is to provide a cleaning device for cleaning.

That is, the present invention provides electrophotography in which a cleaning blade is disposed near a photoreceptor that rotates in a certain direction, and its tip is brought into pressure contact with the surface of the photoreceptor to scrape off and remove toner remaining on the surface. In a cleaning device for a copying machine, the cleaning blade has a particle size of 0.1 μm to
20 parts by weight to 50 parts by weight of polyvinylidene fluoride having a particle size of 1.0 μm and 10 parts by weight of silicon oxide having a particle size of 10 μm to 1.0 μm.
By forming the cleaning blade with a polyurethane resin containing 60 parts by weight, the frictional resistance between the surface of the photoreceptor and the cleaning blade is reduced, thereby preventing wear or deformation of the blade, and the surface of the photoreceptor is This method removes scratches and the like generated on the surface by polishing, maintains a stable cleaning effect over a long period of time, and prevents black spots and the like from appearing on copied images.

Here, the polyvinylidene fluoride has a particle size of 10 μm.
If a particle size of 0.1 μm or more is used, it tends to reduce the abrasion resistance of the cleaning blade, while if a particle size of 0.1 μm or less is used, it is inconvenient to handle and it becomes difficult to uniformly disperse it in the polyurethane resin. As mentioned above, the particle size is preferably in the range of 01 μm to 1.0 μm.

In addition, 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 stick-slip phenomenon, and if it is added more than 50 parts by weight, it becomes difficult to mix with the polyurethane resin. The amount added is preferably in the range of 20 parts by weight to 50 parts by weight.

On the other hand, if silicon oxide 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.
If a material smaller than .mu.m is used, handling becomes inconvenient, so a material in the range of 10 m.mu.m to 1.0 .mu.m is preferable.

Also, the amount added is preferably in the range of 10 parts by weight to 60 parts by weight, similarly to the polyvinylidene fluoride, for reasons of its addition effect and dispersibility.

〔Example〕

Next, an embodiment of the present invention will be described. As shown in FIG.
), and is composed of a cleaning blade (2) manufactured by the following method, 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.

That is, polyvinylidene fluoride 8 is added to the product name Cyanaprene A-7 (polyurethane manufactured by Nippon Cyanamid Co., Ltd.).
0 parts by weight, 20 parts by weight of the product name Aerosil R-972 (smoky silicon oxide manufactured by Nippon Aerosil Co., Ltd.) and 0.05 parts by weight of an antifoaming agent, and after thorough vacuum defoaming, about 120° A heated crosslinking agent is added to C, and the mixture is degassed under vacuum and poured into a mold for a cleaning blade.

Next, primary vulcanization was performed at 100°C for 80 to 90 minutes, and after being removed from the mold, the temperature was 100°C.

Secondary vulcanization is performed for 24 hours, and further aged 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 +21'! r, the contact angle (θ) between its tip and the surface of the photosensitive drum (1) is 5~
It is installed near the photosensitive drum (1) so that the blade (2) and the photosensitive drum (1) are at an angle of 15 degrees.
The cleaning device of the present invention is constructed by applying a pressure of 010-40V.

The cleaning device of the present invention, a cleaning device in which other additives are added to the cleaning blade, and
In order to compare the degree of friction between the cleaning blade and the photosensitive drum surface in each device and the occurrence of black spots on copied images using conventional cleaning devices without additives added to the cleaning blade, we conducted the following tests. A comparative experiment was conducted.

That is, after cleaning the photosensitive drum surface of each device with isopropyl alcohol to remove toner and paper dust adhering to the surface, the photosensitive drum is rotated to bring the cleaning blade into direct contact with the surface for a long period of time. Check for partial curling of each cleaning blade due to friction and the occurrence of stick-slip phenomena, and also make multiple copies in succession to check whether there are white spots, black spots, etc. on the copied images. Examined.

As a result, the results shown in Table 1 below were obtained.

Table 1 No occurrence of O Δ Slight occurrence × Occurrence As is clear from the results, the cleaning device of the present invention is less likely to cause partial curling of the cleaning blade or stick-slip phenomenon than other compared devices. The life of the photosensitive drum was extremely long, the surface of the photosensitive drum was less likely to be scratched, and there were no white spots or black spots on the copied images.

When we actually made 120,000 copies in a row using computer output paper as originals, we found no abnormalities in the cleaning blade or photosensitive drum, and the antifriction effect of polyvinylidene fluoride and the silicon oxide It was confirmed that the polishing effect was significant.

On the other hand, in devices (5 to 11) using cleaning blades containing lubricants other than polyvinylidene fluoride, a slight friction reduction effect appeared, and no stick-slip phenomenon of the cleaning blade was observed. , the cleaning blade is partially turned over,
Its lifespan was not that long.

In addition, when MoS2 was added, the same anti-friction effect as polyvinylidene fluoride appeared, and there was no occurrence of partial curling of the cleaning blade, but on the other hand, the wear resistance of the cleaning blade deteriorated. Therefore, it was not suitable as an additive in the present invention.

Further, in the apparatuses (1 to 3) using cleaning blades to which an abrasive other than silicon oxide was added, the abrasive effect was so severe that the wear resistance of the cleaning plate 1 deteriorated, which was not preferable.

Naturally, in conventional devices, the friction between the cleaning blade and the surface of the photosensitive drum is large, so the life of the cleaning blade is extremely short, and many white spots and black spots can be seen on the copied images. .

〔Effect of the invention〕

As described above, the present invention provides a cleaning device for an electrophotographic copying machine equipped with a cleaning blade, in which the cleaning blade is composed of 20 parts by weight to 50 parts by weight of polyhynylidene fluoride having a particle size of 01 μm to 10 μm and a particle size of 10 μm.
Since it is made of polyurethane resin to which 10 to 60 parts by weight of silicon oxide of μm to 1.0 μm is added, the cleaning blade and the surface of the photoreceptor are It is possible to significantly reduce the frictional resistance between the photoreceptor and the surface of the photoreceptor, and also 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.
The practical effects of the present invention are great, such as being able to maintain the initial cleaning effect over a long period of time and preventing white spots, black spots, etc. that appear in copied images.

[Brief explanation of the drawing]

FIG. 1 is a sectional side 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 sectional side view of the cleaning device. [Code explanation]

Claims (1)

[Claims] A cleaning device for an electrophotographic copying machine 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. , the cleaning blade was mixed with 20 parts by weight 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 10 m.
1. A cleaning device for an electrophotographic copying machine, characterized in that it is made of a polyurethane resin to which 10 to 60 parts by weight of silicon oxide having a particle size of 1.0 to 1.0 μm is added.