JPS646528Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cleaning device for an image forming apparatus such as a copying machine. The present invention relates to a cleaning device that has a function of cleaning and removing attached foreign matter and a function of preventing recording sheets such as copy paper from entering the cleaning device installation area.

Conventionally, as a cleaning method for removing toner from an image bearing member (for example, a photosensitive drum) in an image forming apparatus such as a copying machine (hereinafter abbreviated as a copying machine), a blade edge made of urethane rubber or the like is applied to the surface of the image bearing member. The abutting type is known and is considered to be an effective method because it is suitable for downsizing and simplifying the device and has a large cleaning effect.

Incidentally, the cleaning method using such a blade has the following problems in practical use. That is, when copying paper, which is commonly used as a recording sheet, is used, foreign matter such as paper fibers may accumulate on the blade edge and damage the surface of the image carrier, or the blade may be partially removed from the surface of the image carrier. In addition to floating, which may lead to poor cleaning, rosin deposited from paper or substances present in the air undergo chemical changes due to exposure to corona discharge during exposure, and some of the rosin may be deposited on the surface of the image carrier. However, the problem is that these deposits cannot be removed by a cleaning blade, and may even stick to the surface of the image carrier.

Therefore, in the present invention, a brush is formed using the collected magnetic toner on the side of the surface of the rotating (moving) image carrier before it rotates into the blade disposed portion (the side before the transfer), and the brush is used to hold the image. By bringing it into contact with the surface of the image carrier, it prevents the passage of paper dust and prevents it from accumulating on the blade section, and also supplies the toner collected after cleaning to the surface of the image carrier again, thereby polishing the toner particles on the blade section. This system utilizes this effect to remove firmly attached foreign matter, and furthermore, it is possible to prevent foreign matter from entering deep inside the copying machine through the cleaning device due to poor separation of the copy paper from the surface of the image carrier. Specifically, the present invention is a cleaning device having a cleaning blade for slidingly removing magnetic developer on an image bearing member. A developer carrying means for carrying a magnetic developer is provided on the upstream side in the direction of movement of the image carrier, and the surface of the developer carrying means facing the image carrier has a constant length along the direction of movement of the image carrier. A cleaning device comprising: a non-magnetic member having a length and forming a substantially constant gap with the image carrier; and a rotating magnet disposed on the opposite side of the non-magnetic member from the image carrier. This is a summary.

The present invention will be described below based on embodiments shown in the drawings.

Figure 1 schematically shows a copying machine to which the present invention is applied. In the figure, 1 is a photosensitive drum, which is uniformly charged by a corona discharger 4 and then irradiated with image exposure 5 to correspond to the original. An electrostatic latent image is formed and developed by the developing means 6. In this embodiment, a developing system using magnetic toner is used. The toner image developed on the surface of the photosensitive drum 1 is transferred to the roller 1.
0 and the guide plate 7, a transfer corona discharger 8 applies a charge of opposite polarity to the toner from the back side of the copy paper, and the toner is transferred onto the front surface of the copy paper. Thereafter, the copy paper is separated and conveyed via separation rollers 9, while the surface of the photosensitive drum 1 is cleaned of residual toner after transfer by a cleaning blade 2.

In the above process, a large amount of paper dust is discharged from the copying paper that passes through the guide 7 etc. and comes into contact with the surface of the photosensitive drum, and this adheres to the surface due to the influence of the electric charge on the surface of the photosensitive drum. As described above, these substances may accumulate on the contacting edges, causing damage to the drum and poor cleaning. In other words, if rosin or the like that precipitates from paper powder adheres firmly to the drum surface with a blade, for example, in a film-like manner, these substances will adsorb moisture in high humidity conditions, lowering the surface resistance and disturbing the latent image, or causing the drum to become stained. This increases the frictional resistance on the surface, causing poor cleaning and toner fusion. It is recognized that this phenomenon tends to occur more easily when there is less toner supplied to the copy paper during development, that is, when an original with a small image area and a large amount of white background is supplied.

The present invention was developed by reversing this problem. In other words, this was done based on the inventor's knowledge that the above-mentioned problems, such as the latent image disturbance, which are thought to be caused by adhered substances on the drum surface, can be effectively removed by polishing with toner particles during cleaning. be.

FIG. 2 is an enlarged view of the cleaner section of the embodiment of the present invention, which is disposed at the position indicated by reference numeral 3 in FIG. In the front section on the rotation input side, there is a magnet roller 12 which has magnetic poles appropriately arranged and rotates in the same direction as the drum (both rotate clockwise in the figure), and which is externally mounted on this magnet roller 12 and which controls the rotation of the drum 1. a collecting section 11 consisting of a fixed non-magnetic sleeve 13 having a concave surface of a constant length facing directly along the surface;
A device is provided that includes a recovery screw 14 disposed at a position opposite to the drum 1 of the collection section 11.

Next, to explain the function of the cleaning device including the blade 2, the magnetic toner removed from the drum surface by the blade 2 is transferred to the sleeve 1 of the collecting section 11.
A magnetic brush of a constant thickness is formed on the surface of the sleeve 13 by a scraper 15' which is captured on the surface of the sleeve 13 and the casing 15 also serves as the magnetic roller 12 which rotates in the same direction as the drum.
moves the sleeve surface in the same direction as the drum. Incidentally, excess toner is discharged out of the system by a recovery screw 14. At this time, since the amount of spikes of the magnetic brush normally increases slightly after passing through the scraper, the gap a between the scraper 15' and the surface of the sleeve 13 is
The thickness of the magnetic brush to be formed is set to be smaller than the gap b between the drums, and the thickness of the magnetic brush to be formed is set to be equal to or slightly larger than the gap b, and in accordance with the shape of the opposing concave surface of the sleeve 13 that maintains a constant gap with the drum 1, The drum surface, which is charged with a polarity opposite to that of the toner by the transfer corona discharger, is reproduced, and toner is always supplied to the blade 2 regardless of the document.

As a result of the above action, first of all, since the magnetic brush is in contact with the drum surface, most of the paper fibers and other dust that adhered to the drum surface during the transfer process are peeled off and removed from the surface, and this is then conveyed to the blade section. The above-mentioned problems such as damage to the drum and poor cleaning are greatly reduced, and since the toner supply through contact can always be expected to polish the toner particles at the blade section, foreign particles stuck to the drum surface in a film form can be eliminated. can also be removed,
Furthermore, the effect can be further enhanced by mixing and dispersing an abrasive material such as ClO ₂ in the toner. Furthermore, in the brush contact using a wide area according to this method, since brush contact can be made over a wide area, a contact area of any area can be selected, unlike the conventional case where the brush contact is limited to only a line contact. If a wide contact area is selected, the toner that falls during contact can be captured again on the collection sleeve, which has the advantage of effectively preventing dirt inside the machine and toner scattering.

The cleaning device according to the invention also has the advantage that the shape of the sleeve and its relative arrangement with the blade effectively prevent copy paper from inadvertently entering the device. That is, as shown in FIG. 3, the distance between the drum surface and the drum surface is preferably 0.3~
Because of this arrangement, the sleeve 13, which is arranged so as to have concave surfaces facing each other with an interval of about 2 mm, is able to prevent the conveyance guide of copy paper that may enter the gap between the opposing sides. Moreover, since this gap is minute, the bending of copy paper that adheres to the drum and enters the drum is regulated by this sleeve. Further, in the rear part of the sleeve on the side where the drum rotates, a blade that contacts the drum is arranged at an interval of about 0.3 to 4 mm, so that the copy paper abuts against this blade and is stopped. At this time, the copy paper is held down by the sleeve to the extent that folding is unlikely to occur due to the stiffness of the paper, and the sleeve also effectively prevents the copy paper from folding into a bellows-like shape. The problem of paper entering the device has now been easily solved. FIG. 3 shows a state in which the copy paper 16 is prevented from entering the apparatus by the blade 2 and sleeve 13.

As described above, the cleaning device according to the present invention has a fixed sleeve that allows for easy positioning, and allows contact with the magnetic brush to prevent toner spillage, so that the removal of dust such as fibers and the supply of toner are directly related to the document. This has the advantage of being able to remove foreign matter coated on the drum surface using the abrasive action of toner particles in the blade section, and furthermore, by appropriately setting the outer shape of the sleeve, it is possible to remove foreign matter coated on the drum surface. By providing a function as a copy paper guide plate formed by the cleaning blade or a guide function by a relational arrangement with the cleaning blade, paper folding is prevented, and therefore copy paper is prevented from entering the cleaning device. The practical benefits are extremely large, as it makes it possible to

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus to which the present invention is applied, FIG. 2 is an enlarged view showing an embodiment of the cleaning device according to the present invention, and FIG. It is a figure which shows the stopped state. 1: Photosensitive drum, 2: Blade, 3: Cleaner section, 4: Corona discharger, 5: Image exposure, 6: Developing means, 7: Guide plate, 8: Corona discharger, 9: Separation roller, 10: Roller, 11: Collection section, 12: Magnetic roller, 13: Sleeve, 14: Collection screw, 15: Casing, 15': Scraper, 16: Copy paper.

Claims (1)

[Claims for Utility Model Registration] In a cleaning device having a cleaning blade that rubs and removes magnetic developer on an image carrier, a developer carrier that supports the magnetic developer on the upstream side of the cleaning blade in the direction of movement of the image carrier. The developer carrying means has a non-magnetic material whose surface facing the image carrier has a constant length along the moving direction of the image carrier and forms a substantially constant gap with the image carrier. A cleaning device comprising: a member; and a rotating magnet disposed on the opposite side of the non-magnetic member from the image carrier.