JPS6148881A - 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 forming the cleaning blade of polyurethane resin to which a specific amount of polyvinylidene fluoride of specific particle size is added. CONSTITUTION:The cleaning blade is arranged nearby the photosensitive body which rotates in one direction, and its front end is pressed against the surface of the photosensitive body to scrape toner remaining on the surface. The cleaning device of this electrophotographic copying machine is equipped with the cleaning blade formed of polyurethane resin to which 20-80pts.wt. polyvinylidene fluoride of 0.1-1.0mum in particle size is added. Consequently, the frictional resistance between the photosensitive body surface and cleaning blade is reduced to maintain stable cleaning effect 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 (
An electrostatic latent image is formed on the surface of the bat using an optical system (c), and this latent image is developed with toner using a developer (d) to form a toner image (eJ). (e) The Y toner is transferred onto the paper (g) by the charger (f), and this paper (gl) is peeled off from the photoreceptor (al) by the charger (h) for paper peeling, and By (i), the toner is fixed to obtain a copy.

On the other hand, the photoreceptor (al) after the paper (gl has been peeled off) is charged with a charger (j) for removing static electricity, if necessary, and the toner remaining on the surface is removed by a cleaning device (k+) and then recycled. It has been dried up for use.

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. This method requires a filtration mechanism, making the device complicated and large, and has the disadvantage of being relatively expensive.On the other hand, the magnetic brush method also requires a separate cleaning sleeve that contains an expensive magnet.
In addition, it has the disadvantage that if the residual toner contains toner of opposite polarity, it cannot be removed. Therefore, generally, plate-type cleaning devices that do not have the above-mentioned disadvantage are widely used.

That is, this device has a photoreceptor (a) as shown in FIG.
A cleaning box (illustration) is provided along the length of the cleaning box (provided in the vicinity of the photoconductor tar) and has a partially open part facing the photoreceptor tar, and its tip is connected to the photoreceptor tar. It consists of a cleaning blade (-) attached in pressure contact with the surface of the photoreceptor (11), and the cleaning plate +m+ scrapes off the toner remaining on the surface of the photoreceptor (a) to perform cleaning, and its structure is simple. It is widely used because it can be made smaller, lower in cost, and saves power.

[Problem that the invention seeks to solve]

However, in the cleaning device using the cleaning blade (ml), since the tip of the blade (b) is always in contact with the surface of the photoreceptor (11), the blade (b) is caused by friction with the surface of the photoreceptor (&). r
There was a drawback that the tip of T+) 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 above blade (ml) will be in direct contact with the ml for a long time without passing through the residual toner,
The frictional action becomes thicker, and as a result, the above blade -)
The cover may be warped and turned up significantly, the cover may vibrate due to the stick-slip phenomenon, or the cover may partially turn over.
The cleaning blade ((b) sometimes became deformed.

If the leaning blade (ml) becomes unevenly worn or deformed, a ghost image or striations may appear on the copy paper, significantly deteriorating the copied image, or the blade hJ may cause the photoreceptor to This may cause damage to the surface of No. 11 or even cause peeling of the photoconductive layer.

Furthermore, carriers and paper powder that adhere to the surface of the photoreceptor (81) and are conveyed are likely to enter the gap between the blade &nl and the photoreceptor (a), further increasing the disadvantages described above. had a

For this reason, the blade-type cleaning device has the drawback that the cleaning blade (ml) must be replaced every time approximately 40,000 to 60,000 copies are made, and its maintenance is troublesome.

[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. It is an object of the present invention to provide a cleaning device for an electrophotographic copying machine that does not have the above-mentioned drawbacks by including polyvinylidene fluoride, which has a friction-reducing effect, in the cleaning blade.

That is, the present invention provides electrophotographic copying 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 of the photoreceptor. In the cleaning device of the machine, the cleaning blade has a particle size of 0.1 μn1-
By forming it from a polyurethane resin containing 20 parts by weight to 8 parts by weight of polyvinylidene fluoride of 1.0 μm, the frictional resistance between the surface of the photoreceptor and the cleaning blade is reduced, thereby preventing wear or deformation of the blade. This makes it possible to maintain a stable cleaning effect over a long period of time.

Here, the polyvinylidene fluoride has a particle size of 1.0
If a material with a diameter of 0.1 μm or less is used, it tends to deteriorate the abrasion resistance of the cleaning blade, while if a material with a diameter 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. Therefore, as mentioned above, the particle size is 0.1 pm = 1.0 pm,
Preferably, the range is from 0.2 pm to 0-5 pm.

In addition, 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, whereas if it is added in excess of 80 parts by weight, the ratio of polyurethane in the cleaning plate increases. Since the abrasion resistance decreases, the amount added is preferably in the range of 20 parts by weight to 80 parts by weight, preferably 30 parts by weight to 60 parts by weight.

〔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 polyurethane resin as a heath material and polyvinylidene fluoride as a lubricant.

That is, 50 parts by weight of polyvinylidene fluoride 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. A heated crosslinking agent is added and the mixture is degassed under vacuum and then poured into a mold for a cleaning nog blade.

Next, primary vulcanization was performed at 100°C for 180 to 90 minutes, and after being removed from the mold, vulcanization was performed at 100°C for 24 minutes.
A cleaning blade is manufactured by performing secondary vulcanization for an hour and further aging 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) and photosensitive drum (1) 10 to 40
The cleaning device of the present invention is constructed by applying a pressure of g/am.

Using the cleaning device of the present invention, a conventional cleaning device using a cleaning blade to which no additives are 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 surface of the photosensitive drum of each device with isopropyl alcohol to remove toner, paper dust, etc. 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. The occurrence of partial curling of each cleaning blade and stick-slip phenomenon due to the frictional action was investigated.

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

Table 1 There was no occurrence of partial peeling or stick-slip phenomena, and its lifespan was extremely long.

When we actually continuously made 120,000 copies using computer output paper as originals, we found no abnormalities in the cleaning blade, and the initial cleaning effect was maintained for a long period of time. It was confirmed that polyvinylidene fluoride has a remarkable anti-friction effect.

In contrast, in conventional devices, since no lubricant is added to the cleaning blade, the friction between the cleaning blade and the surface of the photosensitive drum is large, resulting in partial curling of the cleaning blade and stick-slip phenomena. and its lifespan was significantly shortened.

On the other hand, in equipment using cleaning blades containing lubricants other than polyvinylidene fluoride, there was a slight friction reduction effect, and no stain slip phenomenon of the cleaning link plate was observed. However, the cleaning blade partially turned over, and its lifespan was not extended much.

When MoS2 was added, the same anti-friction effect as when polyvinylidene fluoride was added, 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.

〔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 formed of a polyurethane resin containing 20 parts by weight to 80 parts by weight of polyvinylidene fluoride having a particle size of 01 μm to 10 μm. Therefore, due to the lubricating action of polyvinylidene fluoride, the frictional resistance between the cleaning blade and the surface of the photoconductor is reduced. can be significantly reduced.

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. The practical effects of this are enormous.

[Code explanation]

ill...Photosensitive drum

Claims (1)

[Claims] In a cleaning device for an electrophotographic copying machine, 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. . A cleaning device for an electrophotographic copying machine, wherein the cleaning blade is made of a polyurethane resin to which 20 to 80 parts by weight of polyvinylidene fluoride having a particle size of 0.1 μm to 1.0 pm is added.