JP2877858B2 - Method for recovering developer carrier - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a carrier recovery method for a developer used in a wet electrostatic copying machine or a printing machine.

(Prior art)

In a wet electrostatic copying machine or a printing machine, a latent image holding member such as an electrophotographic photosensitive member or an electrostatic recording member is generally rotated while toner particles are dispersed in a developer (a carrier such as an aliphatic hydrocarbon solvent). ), The latent image on the holder is developed, and the obtained toner image is transferred and fixed on a transfer sheet. For this reason, in the machine, solvent vapor is generated from the developing unit, the latent image holder to which the developing solution is adhered, the transfer sheet, and the like due to evaporation of the carrier solvent. It may be. That is, if you make many copies in a small room,
If ventilation is sufficient, such a problem does not occur. However, if ventilation is insufficient, some people may feel an unpleasant odor or even more uncomfortable. As a countermeasure for this, there is a method of recovering the carrier of the excess developer adhering to the latent image holding member or the transfer sheet before or after vaporization. Actually, various methods for recovering the latter after vaporization have been conventionally proposed.However, once the vaporized solvent is recovered, it involves entrapment and liquefaction of vapor. Not practically preferable. Regarding the former recovery method before vaporization, when recovering from a transfer sheet after (immediately after) transfer, for example, a plastic film is used as a transfer sheet for the purpose of obtaining an original drawing for projection, and a most common heat roller is used as a fixing means. When you copy using
At the time of fixing, the roller comes into contact with the image, so that there is a problem that a carrier flow occurs on the image surface and the toner image is disturbed, which is not preferable. On the other hand, in the case of collecting from the latent image carrier after (immediately after) development even in the collecting method before vaporization, such a problem does not occur, and therefore, it is a preferable method. Regarding this type of carrier collection method, for example, Japanese Patent Publication No. 58-30578 discloses a breathable foam roller having a mesh of metal resin or the like on the image surface of a latent image holding member after development and having a core supported inside. After absorbing the excess carrier by pressing, it is recovered by squeezing. However, in order to make the foam roller, it is necessary to wrap the end of the mesh into a groove formed in the roller or fix it to the roller surface with an adhesive so that the surface mesh does not float during use. Due to these treatments, the roller loses its inherent elasticity in the vertical direction considerably, and the thickness of the treated part differs from the other parts, causing uneven contact with the image surface due to this uneven surface thickness. In addition, there is a problem that the image and the surface of the latent image holding member are easily damaged by rubbing the image surface. In addition, although it is not a method of collecting the excess carrier, a method of removing the excess carrier with an air knife (Japanese Patent Application Laid-Open Nos. 63-206786 and 62-151972), a drying method using a blower (Japanese Patent Application Laid-Open No. 63-90263), and a reverse roller Method for regulating thickness of developer layer, method for cleaning residual (untransferred) toner on photoreceptor surface with air permeable foam roller and cleaning solution (Japanese Patent Application Laid-Open No. 54433/1979)
Etc. are known. However, since these methods have different purposes, the excess carrier cannot be collected, and even if such a method is used, the method using an air knife or a blower has problems such as an increase in the size of an apparatus, disturbance of an image, and the like. There is a limit to the amount of excess carrier that can be reduced by the regulation method. (Developers are applied uniformly to the image surface regardless of the image area and non-image area and are thinned. Most of the carrier remains in the image area.) Even if the foam roller used in the above-described cleaning method is used in the carrier collection method, there is a difference in the surface hardness of the roller. Is easily damaged.

[Problems to be solved by the invention]

An object of the present invention is to solve all of the above-mentioned problems in the prior art, and to reduce the size of the apparatus and the size of the image without damaging the image or the surface of the latent image holding member by using the excess developer carrier of the latent image holding member. An object of the present invention is to provide a method of recovering a developer carrier that can be efficiently recovered without disturbance.

[Configuration and operation of the invention]

The carrier recovery method for a developer according to the present invention is a cylindrical air permeable foam roller having a layer of fine particles having a uniform particle size on the image surface after developing a latent image on a rotating latent image carrier with the developer. And the carrier of the excess developer on the holding member is sucked and collected from the inner cavity of the roller.

As shown in FIG. 1, the carrier recovery foam roller used in the method of the present invention has a layer of fine particles 2 having a uniform particle size on a roller body 1 made of a cylindrical air-permeable foam. Reference numeral 3 denotes a roller body, that is, a cavity formed by the foam layer 1, and 4 denotes a foam roller. To make such a foam roller, for example, the outer surface of a cylindrical air-permeable foam layer made of plastic or rubber such as polyurethane or silicone rubber is wetted with a wetting agent such as alcohol, and various resins, Uniform particle size of metal, glass, etc.
m, preferably 1.0 to 20 μm) after uniformly dispersing and adhering the fine particles, heating the whole at a temperature 5 to 10 ° C. higher than the softening point of the fine particles or the foam for 0.5 to 1 hour to obtain the particles or The foam may be softened, and the resin particles may be fused to the outer surface of the cylindrical foam.

Next, the method of the present invention will be described with reference to FIG. 2 and FIGS. 3 (a) and 3 (b). FIG. 2 shows the arrangement and rotational relationship between the foam roller used in the present invention and other members. FIG. 3 (a) is a cross-sectional view, and FIG.
FIG. 2B is a longitudinal sectional view of a main part of FIG. In FIGS. 3A and 3B, the latent image on the latent image holding member 5 which rotates as indicated by the arrow in FIG. 2 is held at a small distance from the surface of the holding member, and rotates in the same direction as the holding member. The toner is developed by the developing solution 9 supplied by the developing roller 6 to form a toner image. Next, the surplus developer layer remaining on the surface of the latent image holding member 5 after development is held at a minute interval from the surface of the holding member, and the thickness is adjusted by a reverse roller 7 rotating in the opposite direction to the holding member. The carrier of the surplus developer layer is depressurized on the suction side of the suction fan 8 in the internal cavity (3 in FIG. 1) of the foam roller 4 which is in contact with the surface of the holder 5 and rotates in synchronization with the holder 5 in the same direction. Similarly, by connecting the exhaust side to the developing tank containing the developer 9, the suction is sucked into the foam layer from between the fine particles on the surface of the foam roller 4, and the exhaust pipe of the suction fan 8 is further discharged from the inner surface cavity.
After passing through 10, it is collected in the developing tank. The foam roller 4 may press the surface of the latent image holding member 5 by utilizing the elasticity of the foam layer to form a nip.

 Hereinafter, the method of the present invention will be described with reference to examples.

Example 1 An apparatus similar to that shown in FIG. 3 was prototyped by modifying the developing section of a wet electrophotographic copying machine CF5085 manufactured by Ricoh Company. For depressurization of the inner cavity of the foam roller and recovery of excess developer carrier, install a suction fan on the back of the copy machine and near the drive gear, and connect the suction side to the cavity and the exhaust side to the development tank with pipes. It was done by doing. The foam roller used had a foam layer made of a breathable polyurethane foam having a cylindrical shape, and the surface layer had an average particle size of 1.5 μm.
m of polymethyl methacrylate particles.

When copying was performed using this apparatus, the amount of carrier remaining on the transfer paper (A-4 size) immediately after the transfer was 100 m.
g.

Example 2 Copying was performed in the same manner as in Example 1 except that the surface layer of the foam roller was formed of polymethyl methacrylate particles having an average particle size of 30 μm. The amount of residual carrier on the transfer paper immediately after the transfer was about 200 mg. Was.

Comparative Example Copying was carried out in the same manner as in Example 1 except that the apparatus from which the foam roller was removed was used. As a result, the residual carrier amount on the transfer paper immediately after the transfer was about 500 mg.

[Function and effect of the invention]

Since the method of the present invention uses a breathable foam roller having a fine particle layer on the surface as described above, the carrier of the excess developer of the latent image holding member can be used without damaging the image or the latent image holding member surface, and There is an advantage that collection can be performed efficiently without increasing the size of the apparatus or disturbing the image. In addition, by appropriately restricting the particle size of the fine particles used for the surface layer of the foam roller, the carrier recovery ability can be kept high.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a foam roller used in the method of the present invention, FIG. 2 is a view showing the arrangement and rotational relationship between the foam roller and other members, and FIGS. 3 (a) and (b) are books. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a transverse sectional view, and FIG. 2B is a longitudinal sectional view of a main part of FIG. DESCRIPTION OF SYMBOLS 1 ... Roller body made of cylindrical air-permeable foam 2 ... Fine particles, 3 ... Cavity 4 ... Foam roller, 5 ... Latent image holder 6 ... Developing roller, 7 ... Reverse roller 8 ... Suction fan, 9 ... Developer 10 ... Exhaust pipe

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hidemi Uematsu 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-3-80274 (JP, A) Sho Akai 53-41941 (JP, U) JP-B-58-30578 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/10 G03G 21/10-21/12

Claims (1)

(57) [Claims] After developing a latent image on a rotating latent image holding member with a developing solution, a cylindrical air-permeable foam roller having a layer of fine particles having a uniform particle size on the surface is brought into contact with the image surface and held. A method for recovering a carrier of a developing solution, wherein a carrier of a surplus developing solution on a body is collected by suction from an inner cavity of a roller.