JPH034284A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the ingress of foreign matter into a developing device and also to prevent contamination of an electrifier and a transfer means by providing a cleaning means at image carrier's edge which is outside the longitudinal image area of an image carrier and which overlaps a cleaning area. CONSTITUTION:After a photosensitive drum 1, which rotates in a direction shown by an arrow (a), is electrified by a primary electrifier 2, exposure 3 is performed to form a latent image. The latent image is developed by the developing device 4, and is transferred to a transfer material 5 by a transfer electrifier 6. Then, the material 5 is separated by the action of a separation electrifier 7, and is carried to a fixing part. On the other hand, residual toner on the surface of the photosensitive drum 1 reaches a cleaner 8, and is scraped by a cleaning blade 9. A drum edge cleaner 10, composed of an edge cleaning blade 11, is disposed; the edge cleaning blade 11 is disposed at both edges of the photosensitive drum 1 in the forward direction with respect to the rotating direction of the photosensitive drum 1; its cleaning area is outside the image area but overlaps the area of the cleaning blade 9.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention forms an image on an image carrier and transfers the image to a transfer material, while the remaining image on the image carrier is transferred to a cleaning means. The present invention relates to an image forming apparatus that forms images by repeatedly using an image bearing member that is cleaned and cleaned.

[Prior Art] Conventional image forming apparatuses repeat the process of transferring a transferable toner image formed on the surface of a moving image carrier onto a transfer material and then cleaning the toner remaining on the surface of the image carrier without contributing to the transfer. It is well known from

In this type of image forming apparatus, methods such as blade cleaning, fur brush cleaning, magnetic brush cleaning, roller cleaning, and combination systems of these are used to remove residual toner. It has been widely used in practice because it is simple, compact, and cost-effective. This type of cleaning blade is slightly wider than the width of the image area on the surface of the image carrier, which travels with a constant width, to easily accommodate errors during assembly during machining, and to ensure that the cleaning blade holds the image reliably. Usually, the structure is such that it can cover the image area of the body. Here, rubber elastic materials are usually used as the cleaning plate, such as polyisoprene, butadiene-styrene copolymer, polybutadiene, polychloroprene, isobutylene-imbrene copolymer, butadiene-acrylonitrile copolymer, ethylene-propylene copolymer. , chlorosulfonated polyethylene, acrylic ester copolymer, polyurethane, organic polysiloxane, perfluoropropene, vinylidene fluoride copolymer, etc. Among these, polyurethane is particularly preferable, and fur brush cleaning, magnetic brush cleaning Generally, the fur brush and magnetic brush are constructed so that they can cover the entire image area of the image carrier.

[Problem to be solved by the invention] However, the length of the cleaning blade is larger than the width of the image area, or the toner accumulated on the edge of the cleaning blade spreads along the edge and flows out of both ends of the blade. As the number of copies increases, this dirt accumulates thickly on the end of the image carrier and scatters inside the machine, causing damage to the charger, developing device, and transfer device. It stains the edges of the means, etc., and corrodes into the image area, causing image defects such as poor charging of the image carrier, foreign matter (toner lumps, etc.) entering the developing device, and poor transfer.

As a solution to these problems, we extended the cleaning width to both ends.
A method of shrinking the part A in Figure 3 has also been proposed, but if the fluidity of the toner changes in that part due to environmental changes, etc.
The above-mentioned toner drifting becomes difficult to occur, and there is no toner to lubricate the contact area between the cleaning plate and the image carrier, and the friction between the two becomes large, causing the moving flN carrier to act as a brake, making the vehicle's running unstable.

There is a risk that vibrations or curling may occur, which may adversely affect the part that is supposed to perform its cleaning action.

Additionally, a method of suppressing the movement of toner to the outside of both ends of the blade by using a sealing member such as felt material or urethane foam material closely attached to the end of the cleaning blade has been implemented, but it is difficult to achieve positional accuracy and is not perfect.

In addition, as a factor contaminating part A in Figure 3, outside the development area (Figure 3)
8) is also mentioned.

[Means for solving the ff problem (and operation)] The present invention has been made in view of the above-mentioned problems, and the present invention has been made in view of the above-mentioned problems. By providing a cleaning means at the end of the fIl carrier which is located outside the image area in the longitudinal direction and has a support that overlaps with the cleaning area, toner scattered at the end from the developing device and the cleaning device is transferred to the end of the image carrier. This prevents foreign matter from entering the developing device, contamination of the charger, contamination of the transfer means, etc. caused by toner accumulation.

[Embodiment] FIG. 1 shows an embodiment in which the present invention is applied to a copying machine, in which a photosensitive drum 1 serving as an image carrier rotating in the direction of arrow a is charged by a negative charger 2. After that, exposure 3 is performed by the light irradiation means to form a latent image. This latent image is developed by a developing device 4 and transferred to a transfer material 5 by a charger 6.
Then, by the action of the separation charger 7, the toner image is separated from the photosensitive drum while being carried thereon and conveyed to a fixing site (not shown).

On the other hand, residual toner that does not contribute to the transfer and remains on the surface of the photosensitive tram l at the transfer site reaches the cleaning device 8.
It is scraped off by the cleaning blade 9 and reaches the storage section in the cleaning device.

At this time, as mentioned above, the particles that accumulate on the edge of the cleaning plate 9 and do not fall into the storage section of the collection container are swept along the edge of the blade and moved to the outside of both ends of the blade in the longitudinal direction. This band-shaped dirt stains the end of the longitudinal direction in the form of a band. As this band-shaped dirt accumulates and increases in thickness, it stains various parts inside the machine, but in the initial state it adheres relatively strongly to the photosensitive tram l, so it does not scatter. .

Therefore, in order to prevent this end from becoming dirty, a drum end cleaning device 1O consisting of an end cleaning brake 1ull is provided. Here, as shown in FIG. 3, the end cleaning blades 11 are disposed at both ends of the photosensitive drum 1 in the forward direction with respect to the rotational direction of the photosensitive drum 1, and the cleaning area thereof is outside the image area, and the area where the cleaning blade 9 is located. It depends on the inside.

In addition, by disposing this tram end cleaning device IO downstream of the developing device 4 and upstream of the cleaning device with respect to the rotational direction a of the photosensitive tram 1, the end of the photosensitive drum 1 due to scattering of the end of the developing device 4 can be removed. It also cleans dirt.

In the embodiment, the drum end cleaning blade 11 is brought into contact with the rotational direction of the photosensitive tram 1 in the forward direction, but it may be brought into contact with the drum end cleaning blade 11 in the opposite (counter) direction.

Further, the tram end cleaning means is not limited to blade cleaning, but may also be fur brush cleaning, magnetic brush cleaning, etc.

Similarly, the cleaning device 8 is not limited to blade cleaning, but may also be a fur brush cleaning, magnetic brush cleaning, roller cleaning, or a combination system thereof.

In addition, although a photosensitive drum was used as the image carrier in the examples,
A belt-shaped photoreceptor may be used, and it goes without saying that the present invention can be applied to copying apparatuses other than electrophotographic ones.

[Effects of the Invention] As explained above, the image carrier has an area located downstream of the developing device and upstream of the cleaning device in the moving direction of the image carrier, which is outside the image area and overlaps with the cleaning area. By providing the body end cleaning means, it is possible to prevent foreign matter from entering the developing device, contamination of the charger, and contamination of the transfer means caused by toner accumulation at the end of the image carrier due to toner scattered at the end from the developing device and cleaning device. Prevent pollution, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of the main parts of a copying machine embodying the invention. Figure 2 is a diagram showing the behavior of toner at the end of the cleaning blade, Figure 3 is a diagram showing the axial positional relationship of the image carrier and its peripheral devices in a copying machine embodying the present invention, 1... Image carrier (photosensitive tram) 2... - Forming charger 3... Exposure 4... Developing device 5... Transfer material 6... Transfer charger 7... Separation charger 8... Cleaning device 9...Cleaning plate lO...Drum end cleaning device 11-...End cleaning plate 7 #'71 and knee>7'lp ←-1--Published←-11

Claims (1)

[Scope of Claims] An image having an area located outside the longitudinal image area of the image carrier downstream of the developing device and upstream of the cleaning device with respect to the moving direction of the moving image carrier and overlapping with the cleaning area. An image forming apparatus characterized in that a cleaning means is provided at an end of a carrier.