JPH0315864A - Process cartridge for image forming device - Google Patents

Abstract

PURPOSE:To make it possible to reuse an electrifying roller, to reduce costs and to improve cartridge effectiveness by simply attaching and detaching only the electrifying roller with respect to the cartridge. CONSTITUTION:On a cartridge frame 16, a photosensitive body 1 is disposed and is driven by a driving source through a gear 14. The electrifying roller 2 abuts on the photosensitive body 1 and is made to abutt with the photosensitive body 1 at positions in the vicinity of both edges of the roller with screw shank 11a and 12a and springs 11b and 12b disposed on holes formed on the film 16. Besides, the roller 2 is positioned in a shaft direction with a screw shank 13a and a spring 13b which are formed on the side of the frame 16 and disposed on a hole whose diameter is bigger than the roller 2. Therefore, the electrifying roller 2 can be taken out from the frame 16 and attached to a new cartridge. Thus, a long life electrifying means is completely used and the costs can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to a process cartridge used in an image forming apparatus using an electrostatic transfer process, such as an electrostatic copying machine or a printer.

(Prior art and problems to be solved) In this type of image forming apparatus, a plurality of members necessary for image formation, such as a photoreceptor, a charging device, a developing device, and a cleaner, are housed in a cartridge. In recent years, various devices have been used from the viewpoint of miniaturization of the entire device, ease of use, and maintenance-free operation.

FIG. 4 is a quick cross-sectional view showing an example of a process cartridge such as the one shown in FIG. A developing device comprising a toner container 10 equipped with rods 8a and 8b, a cleaning device comprising a cleaning blade 6 and a toner reservoir 7 that come into contact with the photoreceptor 1, and a cleaning device that comes into contact with the photoreceptor 1 at the beginning of the image forming process. and a charging roller 2 for uniformly charging the surface of the photoreceptor constitute a cartridge. The charging roller 2 has a metal core 28, is arranged to surround this, and is made of urethane. It consists of a conductive outer layer 2b whose resistance value is adjusted by dispersing carbon, etc. in EPDM or the like. It goes without saying that it is easier for the user to use the cartridge by storing a plurality of parts in a cartridge and making it integrally constructed and disposable. Since the lifespan of the entire cartridge is determined by the member with the shortest lifespan, it is natural that it is desirable that the lifespan of each member be as equal as possible.

However, in reality, this is extremely difficult, and in the case of the above-mentioned cartridge, the photoreceptor 1
Although there are some advantages to using a contact type charging roller to uniformly charge the toner, the lifespan of the roller is much longer than that of the photoreceptor and the capacity of the toner container. This is the reality, and even if the charging roller is no longer usable as a cartridge, the current situation is that the charging roller is still alive.

The present invention has been made to deal with this situation, and makes it possible to reuse the cartridge as described above by configuring only the charging roller to be easily attached to and detached from the cartridge. The objective is to improve the effectiveness of cartridges while reducing costs.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention provides an image forming apparatus equipped with at least a photoreceptor and a contact-type charging means that is in pressure contact with the photoreceptor. The process cartridge is characterized in that the charging means is removably attached to the cartridge.

With this configuration, it is possible to fully utilize a long-life charging means, and the cost of the charging means can be reduced. (Description of Embodiments) FIG. 1 is a sectional view showing the structure of a cartridge such as that shown in FIG. 4, particularly the portion where the photoreceptor 1 and the charging roller 2 come into contact.

In the figure, a photoreceptor 1 is disposed in a frame of a cartridge indicated by reference numeral 16, and this photoreceptor 1 is driven by a drive source (not shown) via a gal 14.

As shown in the figure, the charging roller 2 comes into contact with the photoreceptor l, and at positions near both ends of the roller, screw rods 11a, 12a and springs 1lb. l2b
The roller 1 is pressed against the photoreceptor 1, and is further positioned in the axial direction by a threaded rod 13a and a spring 13b, which are formed in a hole on the side of the frame 16 and have a larger diameter than the roller 2.

With this structure, when replacing the cartridge with a new one due to the end of the life of the photoreceptor, lack of toner, etc., the cartridge is removed from the image forming apparatus, and then the threaded rod 1 is inserted. 1a.
12a, 13a with springs llb, 12b .
13b, etc., and frame the charging roller 2 in the axial direction.
6, attach it to a new cartridge, screw together the screw rods 11a, etc., adjust the position of the roller and the pressing force against the photoreceptor 1 as appropriate, and then attach it to the image forming apparatus. .

By reusing the charging roller in this way, it is possible to use it until the end of its life. Generally, the charging roller can be used repeatedly more than 10 times, so it is configured as described above. This makes it possible to reduce the cost of the roller to 1/10 or less.

FIG. 2a shows another embodiment of the present invention, in which parts corresponding to those in the actual embodiment are designated by the same reference numerals.

In this case, a cleaning brush 17 is formed in the radial direction in the hole through which the charging roller 2 passes through the frame 16, as shown in FIG. 2b.

With this configuration, the charging roller 2 is connected to the frame 1.
Since the surface of the roller 2 is cleaned when it is attached to and detached from the photoreceptor 6, it is possible to prevent charging failures, damage to the photoreceptor, etc., and furthermore, it is possible to extend its life.

FIG. 3 shows still another embodiment of the present invention, a photoreceptor 1,
It is a side view of the vicinity of the cleaning blade 6, in which the same reference numerals are given to the parts corresponding to those of the apparatus of the above-described embodiment.

In this device, as the charging means, as described above,
One edge of a blade-shaped blade 18b made of EPDM rubber or the like whose resistance value has been appropriately adjusted is pressed against the photoreceptor l, the other edge is supported by the support member 18a, and the cartridge is screwed into place with the thumbscrew L9. A bias voltage is applied by a power source (not shown) via the support member 18a.

When replacing the cartridge, after taking it out, release the thumbscrew l9 and remove the charging blade 18b.
Simply remove the blade and attach the blade to a new cartridge.

With such a configuration, the charging means can be housed in an even smaller space.

(3) Effects of the Invention As explained above, according to the present invention, a long-life charging member is maintained until the end in at least a cartridge integrally configured with a photoreceptor and a contact-type charging means in contact with the photoreceptor. It can be used effectively and greatly contributes to cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main part of a cartridge showing an embodiment of the present invention, FIGS. 2a and 2b are a sectional view and a partial end view of the main part, respectively, showing an embodiment of the invention, The figure is a side view of a main part showing another embodiment of the present invention, and FIG. 4 is a sectional view showing the structure of a known process cartridge. DESCRIPTION OF SYMBOLS 1...Photoreceptor, 2...Charging roller, 4...Developing sleeve, 6...Cleaning blade, 7...Toner reservoir, 10...Toner container, 11a. l2a, 1
3a...Screw rod, llb, 12b, 13b...Spring, 17...Cleaning brush. iab...Blade for charging. r Official A1 1 Figure 2a Figure 2b Figure 3 Figure 4

Claims (2)

[Claims] (1) A process cartridge for an image forming apparatus, which is equipped with at least a photoreceptor and a contact-type charging means that presses against the photoreceptor, the charging means being removably attached to the cartridge. (2) Claim 1 in which the charging means is a charging roller
Process cartridge as described in section. (3) The process cartridge according to claim 1, wherein the charging means is a plate-shaped charging blade.