JPH0616206B2 - Development sleeve manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a developing sleeve, and more particularly to a method of manufacturing a developing sleeve applicable to a developing unit of an image forming apparatus using a belt-shaped photoreceptor. .

(Prior Art) Conventionally, there is known an image forming apparatus of a type in which development is performed with toner, in which a drum-shaped photosensitive member is used as an image carrier. It is also well known that a developing sleeve is used as a developing device that supplies toner to the electrostatic latent image on the photoconductor to visualize it.

By the way, in the above-mentioned conventional developing device, when a large area electrostatic latent image (so-called solid image) is visualized and when a small area electrostatic latent image (so-called line image) is visualized. Then different demands are imposed.

This is explained using an electronic copying machine as an example. When the image of the original to be copied is a line image of a small area, even when the density of the line image in this original is relatively low, the original image There is a demand to obtain a copy image with a density higher than that of the original. On the other hand, when the original image is a solid image with a large area, a copy image with a density corresponding to the density of the solid image in this original is obtained. There is a demand. This requirement is satisfied to some extent by the action of the carrier in the two-component toner, but there is a problem in the one-component toner.

Therefore, as a technical means to meet such a demand particularly when a one-component toner is used, an improved developing sleeve is disclosed in JP-A-57-114163. According to the disclosed technique, an insulating layer is formed on the outer periphery of a cylindrical conductive support, and a large number of microelectrodes are arranged on the peripheral surface of the insulating layer while maintaining an electrically insulated state from each other. Will be provided.

When developing is performed using the developing sleeve having such a configuration, it is convenient to obtain the initial developing performance that meets the above requirements, but on the other hand, depending on the configuration of the developing sleeve, the photosensitive member may be used. When a belt-shaped member is used as the above, there arises a problem that the conductive support and the photosensitive member come into contact with each other and the bias current leaks.

The conventional developing sleeve that causes the above problems is
Reference numeral 10 is shown in FIGS.

In the figure, reference numeral 1 indicates a multi-pole magnet, which is axially supported by a bearing 3 of a flange 2. The flange 2 is press-fitted into a cylindrical sleeve core metal 4 serving as a conductive support, and an insulating adhesive layer 5 is formed on the outer periphery of the sleeve core metal 4. Further, an adhesive layer 5 ′ made of the same material as the adhesive layer 5 is formed on the outer periphery of the adhesive layer 5,
On the outer peripheral surface, minute electrodes 6 made of a large number of copper particles having a diameter of about 10 to 500 μm are arranged while maintaining an electrically insulated state from each other.

In such a developing sleeve 10, a portion not covered with the adhesive layer 5 is formed at the end of the sleeve core metal 4 in the axial longitudinal direction over the dimension t.

This is due to the procedure in the manufacturing process as will be described later. However, since the exposed portion over this dimension t is in a smaller diameter portion than the adhesive layer 5 ', for example, the photosensitive member is drum-shaped having rigidity. When it is formed on a support, even if it is placed close to such a photoconductor, the phenomenon that the bias current leaks through the exposed portion of the sleeve core metal 4 does not occur.

However, when a belt-shaped member is used as the photoconductor and the photoconductor is configured so as to be in contact with the peripheral surface of the developing sleeve 10 while being bent as shown by reference numeral 7 in FIG. There is a problem in that the photosensitive member comes into contact with the exposed portion and the bias current related to the bias voltage applied between the photosensitive member and the sleeve core metal leaks, which affects image formation.

By the way, in FIG. 3, reference numeral 8 indicates the magnetic toner dropped from the toner cartridge 9 and supplied to the developing sleeve 10.
The toner sent by the feed plate 8 is a magnet 1 rotated in the arrow direction at different rotation speeds, and a sleeve core metal 4 rotatably covering the magnet 1.
While configuring the magnetic brush according to the rotation of the, the thickness is regulated by the doctor blade 11 and sent to the contact portion with the photoconductor,
The toner is appropriately adsorbed to the electrostatic latent image portion of the photoconductor and provided for development.

Here, it is due to circumstances in the manufacturing process that an exposed portion which is not covered with the insulating layer is formed over the dimension t at the axial end portion of the sleeve core metal 4.

For example, in the conventional manufacturing process, first, the sleeve core metal 4 is covered with a rubber cap so as to cover a portion extending over the dimension t, and the adhesive 5 is applied to the outer periphery. Next, after waiting for the adhesive layer 5 to dry, the rubber cap is removed, and the outer periphery of the adhesive layer 5 is cut and finished using the inner diameter portion of the sleeve core metal 4 as a processing standard. Next, the rubber cap is covered again to form the adhesive layer 5 ', copper particles serving as the microelectrodes 6 are pushed into the peripheral surface, and after waiting for drying and solidification, the rubber cap is removed, and then the sleeve core is again formed. The outer circumference is cut and finished using the inner diameter of the gold 4 as a working reference. After that, the flange 1 is press-fitted while holding the magnet 1 in the inner diameter portion of the sleeve core metal 4 to finish the processing.

In such a manufacturing method, since the inside of the sleeve cored bar 4 is used as a processing standard, the above rubber cap must be covered to prevent the intrusion of the adhesive, and therefore the dimension t of the rubber cap portion is t. Therefore, the exposed portion that is not covered with the adhesive remains.

Then, when such a developing sleeve is used in combination with a belt-shaped photoreceptor, a bias voltage leak may occur.

(Objective) Accordingly, the present invention is to provide an improved developing sleeve manufacturing method capable of insulating-coating a required portion so as not to cause a bias voltage leak.

(Structure) The structure of the present invention will be described below based on an embodiment.

The developing sleeve according to the present invention is shown in FIGS. The developing sleeve 12 in the figure has a structure in which the outer peripheral surface of the sleeve cored bar 4 is entirely covered with an adhesive layer 5 and further covers the side surface of the flange 2 to eliminate the problem of bias leak due to contact with the belt-shaped photoreceptor. ing.

Such a developing sleeve is manufactured by the following procedure.

First, the magnet 1 is temporarily placed inside the sleeve core metal 4, and then the flanges 2 having the shaft portions 2a at both ends are press-fitted. At that time, the bearing 3 is also mounted at the same time.

After that, the first adhesive layer 5 is formed so as to cover the outer peripheral surface of the sleeve core metal 4 and the side surface portion of the flange 2.
After drying and solidification, the outer periphery of the flange 2 is processed using the shaft portion 2a of the flange 2 as a processing standard for chucking and centering, and then the second adhesive layer 5'is formed on the outer periphery of the adhesive layer 5. Is formed by coating. Then, before the second adhesive layer 5'is dried and fixed, a plurality of microelectrodes 6 made of a material such as copper particles are embedded in the surface of the adhesive layer 5 '. Then, after the second adhesive layer 5'has been dried and solidified and the fine electrodes 6 have been fixed, the outer periphery of the flange 2 is finished by using the shaft portion of the flange 2 as a processing reference for chucking, centering, etc. The surface of the electrode 6 and the surface of the second adhesive layer 5'are finished so that they are flush with each other.

According to such a manufacturing procedure, since the shaft portion 2a of the flange 2 is used as a processing reference, it is not necessary to use a rubber cap as in the prior art, and the outer periphery of the sleeve core metal 4 is completely insulated with an adhesive. Can be covered.

(Effect) In the developing sleeve according to the present invention, the portion of the sleeve core metal, which may be in contact with the belt-shaped photoreceptor, is covered with a sufficiently insulating adhesive. This is convenient because the harmful effect of leaking due to contact with will not occur.

[Brief description of drawings]

FIG. 1 is a perspective view of a developing sleeve according to the prior art, FIG. 2 is a cross-sectional view of the same as above, and FIG. 3 is a cross-sectional view of a developing device and a photoconductor device for explaining a contact state of a belt-shaped photoconductor with the developing sleeve. FIG. 4 is a sectional view of the developing sleeve for explaining the embodiment of the present invention, and FIG. 5 is a perspective view of the developing sleeve shown in FIG. 2 ... Flange, 4 ... Sleeve core metal, 5 ... First adhesive layer, 5 '... Second adhesive layer, 6 ... Microelectrode.

Claims (1)

[Claims] 1. A toner supply means arranged in contact with a belt-shaped photosensitive member, wherein an insulating layer is provided on the outer periphery of a cylindrical conductive support, and a large number of microelectrodes are provided on the peripheral surface of the insulating layer. In a developing sleeve which is arranged so as to be electrically insulated from each other, a cylindrical sleeve mandrel made of a conductive material is press-fitted with flanges having shafts at both ends, and then the sleeve mandrel is inserted. An insulating first adhesive layer is formed so as to cover the outer peripheral surface of the gold and the side surface of the flange, and then the first adhesive layer is formed.
After forming the second adhesive layer on the adhesive layer of
A method of manufacturing a developing sleeve, which comprises forming a plurality of microelectrodes on the adhesive layer.