JPH01319084A - Image forming device cleaning device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that utilizes an electrostatic transfer process, such as an electrostatic copying machine or a printer, and particularly to a cleaning device therefor. be.

(Prior Art and Issues to be Solved) In a well-known image forming apparatus that repeatedly transfers a transferable toner image formed on the surface of an image carrier onto a sheet-like transfer material mainly made of paper, Therefore, it is essential to remove toner that does not contribute to transfer and remains on the image carrier.
For this reason, it is well known that cleaning blades made of elastic materials such as rubber are widely used as cleaning means because they have an excellent residual toner removal function, are simple in construction, and are advantageous in terms of cost.

Furthermore, although the above-mentioned leaning blade has an excellent residual toner removal function, it is also susceptible to the presence of fine paper particles, rosin, talc, and other precipitates that occur due to the use of paper as a transfer material, or the presence of high-pressure components inside the device. There are some imperfections in removing foreign matter adhering to the image carrier, such as corona products caused by It is well known that this method has been effective to a certain extent in removing toner and foreign substances such as those mentioned above.

However, even with such devices, it is difficult to eradicate cleaning defects in reality, and cleaning defects sometimes occur particularly in high temperature and high humidity environments.

There are various reasons for this, of course, but in a cleaning device that uses a cleaning blade, as shown schematically in FIG. Usually, one edge of the edge 30a of the formed cleaning blade 30 is pressed against the other, so the friction between the two is quite high, and the physical properties of the rubber deteriorate due to long-term use or environmental changes. The tip of the blade, especially the edge portion that contacts the image carrier, may sometimes move downstream of the image carrier in the traveling direction due to changes in the image carrier, or irregularities caused on the surface of the image carrier due to the above-mentioned foreign matter. As shown by reference numeral 30b in the figure, the toner repeatedly turns over and then returns to its previous position due to the elasticity of the blade itself, causing so-called chatter. At this time, the toner passes between the image carrier and the blade, resulting in poor cleaning. It has been found that poverty is one of the causes of poverty.

The present invention has been made in order to cope with the current situation, and it is an object of the present invention to maintain the friction between the blade and the image carrier as small and stably as possible in a cleaning device that uses a cleaning blade. Therefore, it is an object of the present invention to provide a leaning device that can perform good leaning at all times.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention includes an image bearing member and a cleaning blade that comes into pressure contact with the image bearing member and removes residual toner. In the image forming apparatus, a means is arranged to mix fine particles with a smaller diameter into the residual toner before the residual toner reaches the position of the cleaning blade, and the cleaning blade is configured to pass only the fine particles. The present invention is characterized in that a portion is provided adjacent to the cleaning blade, where the removed toner stays in a timely manner.

With this configuration, it is possible to reduce the friction between the cleaning blade and the image carrier, and to maintain this state for a long period of time.

(Description of an Embodiment) FIG. 1 is a side view of a main part of an embodiment in which the present invention is applied to a copying machine equipped with a cylindrical image carrier that rotates in the direction of arrow A. In this case, it is assumed that the axis of the image holding body 11 is arranged to extend in the horizontal direction, and the cleaning device 2 is arranged near the top thereof.

Inside the cleaning device 2, a cleaning blade 3.
Magnet roller 4. A conveying screw 5 is provided, and when residual toner that has not been transferred to the transfer material at a transfer position (not shown) reaches the position of the blade, it is scraped off from the image carrier, and furthermore, the above-mentioned adhered foreign matter is scraped off. is mainly removed by the action of the magnet roller 4,
Due to the location of the cleaning device, these toners remain on both sides of the upper side of the blade 3 for a while, and then are transported to the toner storage section by the action of the magnet, and are further transported and discharged out of the device by the screw 5 as necessary. shall be taken as a thing.

Although not shown in the drawings as they are not directly related to the present invention, a charger, a developing device, a transfer means, a separation means, and other members necessary for image formation are arranged around the image carrier. Needless to say, it is.

In the leaning apparatus as described above, in the present invention, particles having a particle size within a range of 10 to 500 m and a volume resistivity of 10'ΩC1 or more, for example.

An appropriate amount of particles such as silica or zinc stearate is added to the toner before it reaches the cleaning blade 3, and the angle at which the cleaning blade contacts the image carrier and the shape of the contact edge are appropriately determined. This allows the particles to pass through the blade 3 while maintaining the function of removing the toner from the image carrier by the blade 3.

With this configuration, as shown in an enlarged view in FIG. 2, the W1 fine particles P enter between the surface of the image carrier 1 and the edge of the cleaning blade 3 and act as a lubricating member. This reduces the friction between the blades and stabilizes its value, thereby preventing the chatter phenomenon described above and the resulting curling of the blade, thereby preventing poor cleaning.

As a means for adding the fine particles to the toner, in the apparatus described in 1-, a web 6 on which fine particles are attached is placed on the 1 side of the cleaning device 2 when viewed from the running direction of the image carrier 1.
is arranged so that when the image carrier carrying residual toner arrives at this position, particles are sequentially supplied from this web.

? ! The 1 fB particle supply means is not limited to such a means, and although not shown, for example, particles may be stored in an appropriate container and intermittently supplied to the image carrier at appropriate intervals. It may be configured to do so.

Furthermore, the fine particles that have passed through the cleaning blade have a small particle size, and in the case of a small amount, there is no particular negative effect on subsequent image forming operations, but it goes without saying that these particles are indispensable. As in the illustrated apparatus, it is preferable to use a brush 7 to rub the surface of the image carrier to remove particles.

As the brush, a Nomex bristle brush can be used, but other materials such as puller sheets, urethane sheets, etc. may also be used as blades.

To briefly summarize the results of the experiment, the contact pressure of the blade 3 on the image carrier was 3 to 20 gr/c, the contact angle was 3 to 30' in the counter direction, and silica with a particle size within the above range was used. By supplying small amounts at any time and using a Nomex bristle brush as a particle collection member, a stable cleaning action was obtained without chatter or poor cleaning.

If the particle size exceeds 500 cm, the particles passing through the blade 3 may adversely affect the next image or contaminate various parts within the device, such as the charging wire of the charger.

Also, the contact angle of the cleaning blade to the image carrier is
Particularly good results were obtained when the angle was 10-20°.

Furthermore, as shown in FIG. 3, r=0. 01
By giving the blade a roundness of ~1.0 mm, the allowable range of the contact pressure of the blade to the image carrier can be increased to 3~40 gr/c.
It turned out that it can be expanded as ■. The above-mentioned roundness r is equal to 0.0 mm of the average particle diameter of the toner. Good results were obtained when the particles were 1 to 10 times larger than that of the fine particles.

When the brush 7, which is a collection member, is installed, the brush 7 has a concentration of 1.0XlO-1 to 1.0XlO-1 for each rotation of the image carrier.
- It was preferable to allow the fine particles of "gr" to pass through the blade.Also, when no brush is provided,
t, oxio"" or 1. Good results were obtained at about OX 10-' gr.

FIG. 4 is a graph showing water saving changes in the coefficient of friction between the cleaning blade and the image carrier depending on the number of sheets passed in the case of the conventional cleaning method (a) and the case of the present invention (b). indicates the level at which blade curling and cleaning failures begin to occur frequently.

In the conventional cleaning method, the coefficient of friction increases as the number of sheets passed increases, causing the blade to turn over.
In the present invention, the friction coefficient is set to 1/2 to 1/2 of the above case.
It can be seen that it is possible to reduce the amount to about 1/10 and maintain this level stably.

As mentioned above in the description of the apparatus shown in FIG. It is desirable that the image carrier remain on the surface of the image carrier for a while after being removed.

However, if it stays for too long, the fine particles are consumed and the lubricating function is reduced.

FIG. 5 is a graph for saving water in such a situation,
Image carrier surface photosensitive layer, cleaning blade material,
Since there are differences depending on various conditions such as the I'A arrangement, toner, and the substances that make up the additive particles, it is difficult to make general statements, but as a trend, as shown in the same graph, the content of fine particles (as shown in the figure) It has been found that when the curve e) becomes lower than 4 (d% in the figure), blade curling and cleaning failures suddenly occur frequently.

Therefore, the time t (the number of sheets passed) at which such a situation occurs is determined by experiment, and the 8th
As shown in the figure, the rotary blade 9 is rotated to remove the staying toner, develop and form a toner band on the image carrier, and send the toner with a large fine particle content to the cleaning device. It is better to

FIG. 6 shows another embodiment of the present invention, in which parts corresponding to those in the previous embodiment are denoted by the same reference numerals, and explanations thereof will be omitted unless otherwise necessary. Omitted.

In this device, the cleaning device 2 is arranged in such a direction that the toner scraped off by the cleaning blade falls almost vertically downward, so that the toner stays at a suitable position on the upstream side of the cleaning blade 3. A retaining member 8 is provided so that the toner scraped off by the cleaning blade is temporarily retained in this portion, so that there is no problem in the supply of fine particles that should act as a lubricant.

In this case, a small gap is formed between the retention member 8 and the image carrier so that the toner that was previously stored and whose fine particles have been consumed can easily escape from the retention portion. It is better.

With this configuration as well, the same effect as in the embodiment described above could be obtained.

The embodiments of the present invention are as follows.

(2) An image forming apparatus according to the claims, further comprising means for discharging the toner that is removed and remains by a cleaning blade.

(3) Effects of the Invention As can be understood from the above description, the present invention provides a cleaning device for an image forming apparatus in which residual toner is removed by a cleaning blade.
Without impairing the cleaning blade's excellent toner removal function, the friction between the cleaning blade and the image carrier can be extremely reduced, and this state can be maintained for a long period of time, so a stable cleaning action can be obtained at all times. , which greatly contributes to obtaining high-quality images.

[Brief explanation of the drawing]

FIG. 2 is a sectional side view of a main part of a cleaning device showing an embodiment of the present invention, and FIG. 2 is an enlarged side view of a part of the same as above. FIG. 3 is a side sectional view showing another embodiment of the invention. Figure 4 is a graph showing water saving changes in the coefficient of friction as the number of sheets of paper increases between the present invention and a known cleaning device. Figure 5 is the content of fine particles contained in toner scraped off by the cleaning blade. FIG. 6 is a side view of essential parts showing another embodiment of the present invention; FIG. 7 is an explanatory diagram showing the operation of the edge of a known cleaning blade; FIG. FIG. 7 is a side view of a main part of a cleaning device showing still another embodiment of the present invention. l...◆Image carrier, 2 fight fist/cleaning device, 3...
・Cleaning blade, 7. Brush, 8. Retention member, 9. Rotating blade. Figure 1m Figure 2 Figure 3 Figure 94 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] In an image forming apparatus that includes an image bearing member and a cleaning blade that comes into pressure contact with the image carrier and removes residual toner, the residual toner is further removed from the toner by the time the residual toner reaches the position of the cleaning blade. The cleaning blade is arranged to allow only the fine particles to pass therethrough, and a portion is provided adjacent to the cleaning blade where the removed toner remains at a suitable time. A cleaning device is provided.