JPS6238703B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method of developing electrostatic latent images using a colored developer. More specifically, the present invention relates to a developing method in which ferromagnetic particles and a colored developer are held on a magnetic roller.

The conventional electrophoretic development method using charged colored particles dispersed in an insulating liquid has the following drawbacks because the developer comes into contact with the entire surface of the latent image.
For example, unnecessary solvent adheres to non-image areas, which tends to cause scumming, and the amount of solvent that evaporates is large, which may harm environmental hygiene. Furthermore, in order to remove excess developer, a corona charger, a blade, etc. are required before transfer, but this causes abrasion of the photoreceptor and abrasion of the blade, which tends to cause adverse effects on images such as scumming.

As a method to solve these drawbacks, the developer is held in the recesses of the applicator, which has minute irregularities on its surface, using capillary force or other adhesive forces, and is brought into close contact with the electrostatic latent image to remove only the latent image area. There are selective wet development methods (see, for example, Japanese Patent Publication No. 39-4299 and Japanese Patent Publication No. 29135), in which a developer is suctioned and adhered to the film, and conductive liquid development methods (see, for example, US Pat. No. 3,084,043).

However, even in these methods, it is necessary to manufacture the applicator surface uniformly and with high precision in order to make uniform contact with the electrostatic latent image, and it is necessary to use a doctor to homogenize the developer that adheres to the recesses of the applicator. However, it has drawbacks such as wear on the applicator surface, making it difficult to put it into practical use.

The purpose of the present invention is to eliminate these conventional drawbacks,
The object of the present invention is to provide an easy, inexpensive, and practically useful developing method and developer. That is, in the present invention, a magnetic roller is immersed in an electrostatic image developer containing ferromagnetic particles and a colored developer, the ferromagnetic particles are uniformly adhered onto the magnetic roller, and the ferromagnetic particles are mutually bonded. An electrostatic image developing method characterized by holding a colored developer in the gap formed between the two by its surface tension, capillary force, etc., and developing an electrostatic latent image on the surface of a photoreceptor with this colored developer. be.

The developing method according to the present invention will be described later in accordance with Examples.

The developer used in the present invention is as shown in FIG.
Ferromagnetic particles 1, 1 are uniformly distributed on the surface of the developing roller 3.
... is attached, and the colored developer 2 is used in the form that it is attached to the concave gap formed between the ferromagnetic particles 1, 1... due to its surface tension, capillary force, etc. . When this comes into contact with the electrostatic latent image, only the colored developer 2 charged by electrostatic induction or charge injection from the applicator is attracted to the latent image and forms an image.

When the particle size of the ferromagnetic particles 1 becomes small, they adhere to the latent image surface together with the colored developer 2, and when the particle size becomes large, the resolution tends to deteriorate. 300μ is optimal. Further, as for the shape, a spherical one with a uniform particle size is particularly suitable, but it is not necessarily spherical and a special shape can also be developed.

Furthermore, the ferromagnetic particles in the present invention can be coated with a resin such as fluororesin, acrylic resin, butyral resin, or styrene/methyl methacrylate copolymer to modify the surface properties. It is also possible to use the
The resin in this case is preferably one that does not dissolve in the solvent constituting the developer.

The colored developer is not particularly limited, and can be appropriately selected from known electrophotographic developers.

For example, Isopar G, Isopar H, mineral oil, silicone oil, kerosene, water, etc. are used as dispersion solvents, and examples of dispersion resins include acrylic esters, rubber resins grafted with acrylic, and ethyl phthalylethyl. Examples include glycolate and dibutyl phthalate. These resins are also effective in improving fixing properties.

As the coloring agent, both pigments and dyes can be used. As the colorant particles, any colored particles or dyes in a dissolved state can be used as long as they are fine particles that do not cause particle migration, preferably 0.5 μm or less.

For example, pigments such as Carbon Black, Phthalocyanine B, Vegetable Yellow G, Fire Red, CISolvent Yellow 2, 6, CISolvent
There are dyes such as Blue2, 11, CISolvent Red1, and 3.

When the colorant is in the form of particles, a surfactant can be added to disperse it. Examples include alkylated polyvinylpyrrolidone, long-chain cyclic polyamine, sorbitan monooleate, polyoxyethylene cetyl ether, polyoxyethylene nonyl phenyl ether, dioctyl sulfonsuccinate, organic phosphate ester, and the like.

Next, the developing method of the present invention will be explained with reference to the drawings.

Figure 2 shows the outline of the device, where 4 is Se,
A photosensitive drum made of an organic semiconductor or CdS, etc. is appropriately charged with a charging corona charger 5, and an image is irradiated with an exposure section 6 to form an electrostatic latent image. Next, development is performed by the developing roller 3, and the image is transferred to the transfer paper 8 by the transfer corona charger 7. The surface of the photoreceptor is then cleaned by a cleaning roller 9 for repeated use.

FIG. 3 shows an embodiment of the developing section according to the developing method of the present invention, where the developing roller 3 is connected to the developer tank 10.
It is partially immersed in the colored developer 2 contained therein. The developing roller 3 has magnets 12, 12, . . . fixed radially around a shaft 11. On the outside there is a rotatable sleeve 13. Of course, the shape of this magnet and the number of magnetic poles are not limited to those shown in the drawings. The ferromagnetic particles 1, 1, . The colored developer 2 is held between the ferromagnetic particles 1 and 1, as shown in FIG. 1, and is conveyed to the surface of the photoreceptor 4. Then, development is performed only on the latent image portion of the photoreceptor 4 at a point where the surface of the photoreceptor 4 and the developing roller 3 are close to each other or in contact with each other.

By applying a voltage to the developing roller 3, reversal development, background smear prevention, etc. can be achieved.

The relative surface ratio between the surface of the photoreceptor and the surface of the developing roller is preferably 1/1 to 1/5, and 1/1 to 1/3.
is optimal.

In this embodiment, the bottom of the developer tank 10 is provided with an appropriate slope so that the ferromagnetic particles 1 scraped off by the doctor blade 14 do not accumulate in one place of the developer tank 10. Furthermore, since the ferromagnetic particles 1 once developed are scraped off by the scratching blade 15, a stirring effect is produced on the ferromagnetic particles 1, thereby preventing aggregation and precipitation in the colored developer. Note that the developing roller in the above embodiments does not necessarily have to be of the type shown in the drawings, and may be of a moving belt type wound around a roller.

The present invention is as described above, and although a liquid developer is used, development can be carried out extremely easily by skillfully utilizing the capillary force and adhesive force of the liquid developer, and in particular, it does not require special equipment. There is no need to use it, fixing is easy and may not be necessary in some cases, the amount of developer used is small, and the amount of solvent evaporated is also small. Furthermore, it is easy to manufacture and can be colored, making it extremely useful.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the state of the developer of the present invention during development, FIG. 2 is a schematic explanatory diagram of an example of an apparatus embodying the method of the present invention, and FIG. 3 is an enlarged explanatory diagram of the developing portion. 1...Ferromagnetic particles, 2...Colored developer, 3...Developing roller.

Claims (1)

[Claims] 1 A magnetic roller is immersed in an electrostatic image developer containing ferromagnetic particles and a colored developer, and the ferromagnetic particles are uniformly adhered onto the magnetic roller, and the gaps formed between the ferromagnetic particles are 1. An electrostatic image developing method comprising: holding a colored developer, and developing an electrostatic latent image on a photoreceptor surface with the colored developer.