JPS6180164A - Color developing method - Google Patents

Abstract

PURPOSE:To facilitate development of a desired color in a short time with a simple structure by feeding developers of >=2 colors onto a developer carrying roller. CONSTITUTION:Cyan, magenta, and yellow developers are placed in vessels 12-14 in a developing device 4, and the developers are fed to the developing roller 8 by rotating feed rollers 9-11. When green is wanted, the developers are mixed through the subtractive color process by rotating rollers 9, 11. The developers not used for the development are recovered in a vessel 18, but they are turned into a color like black by said subtractive mixing, and so they are introduced into a black vessel 16 and may be reused. Each of red, blue, and green can be reproduced and other colors can be reproduced by changing their mixing proportions, thus permitting development of desired colors to be executed easily in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing method used in image forming apparatuses such as electrophotographic copiers, laser beam printers, and magnetic printers, and in particular to a developing method using a mixture of two or more color developers such as red and blue. The present invention relates to a color developing method for developing an a-image on a latent image holding member.

Conventionally, color image forming apparatuses have been known in which a plurality of developing units for magenta, yellow, cyan, black, etc. are arranged around a photosensitive drum, and color images are obtained by sequentially reversing development and transfer. There is. Also, JP-A-54-1247
No. 32 discloses an improvement to the conventional color device described above.

A plurality of developer supply rolls of different colors are arranged around one developing sleeve, and during development, one of these supply rolls is rotated to apply one color of developer onto the developing sleeve for development and transfer. An apparatus has been proposed in which a color image is obtained by first applying developer of another color to the sleeve and repeating development and transfer. However, in any of the above cases, the A image is developed in a single color and the colors are overlapped during transfer, and the colors are monochrome (magenta, yellow, etc.).

When attempting to reproduce a color image other than cyan, black), a series of processes such as latent image formation, development, and transfer must be repeated at least twice, resulting in the disadvantage that it takes a lot of time to form a single color image. There is.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks of the conventional method and to provide a color developing method capable of forming a color image 1'R in a short time with a simple configuration.

The present invention involves mixing two or more color developers on a developer carrier, and developing a latent image on an m-image holding member with the mixed developer.

That is, 1. For example, a green developed image is obtained by mixing yellow and cyan developers on a developer carrier to develop a latent image. 1. According to the present invention, a green developed image is obtained by mixing yellow and cyan developers on a developer carrier. A large number of colors can be developed using a developer.

Examples of the present invention will be described in detail below.

FIG. 1 is a schematic cross-sectional view of an image forming apparatus to which the color developing method of the present invention is applied. In the figure, 1 is a latent image holding member having a photoconductor such as Be, 068, etc. on its surface, and in this embodiment is a photosensitive drum. . This photosensitive drum 1 is manufactured by Japanese Patent Publication No. 42-23910.
An insulating coating 7'' may be applied on the photoconductive layer used in the electrophotographic method described in the above publication. It may be an insulated drum used in a method (retention method) in which an electrostatic latent image is transferred from a screen drum on which a latent image is formed, or a magnetic drum used in a magnetic printer. Alternatively, a belt-type latent image holder may be used.

In this embodiment, a photosensitive drum 1 is charged by a corona discharger 2, subjected to optical image exposure via an optical system 5, and
An electrostatic latent image is formed on the optical surface. A latent image may be formed using an electrode needle or a magnetic head. 4 is a developing device for achieving color development of the present invention, which will be explained in detail later; 5
is a transfer charger for transferring the developed image onto the transfer material 7;

Reference numeral 6 denotes a separation corona discharger for separating the transfer material 7 from the photosensitive drum 7. The transfer material 7 after transfer and separation is transferred to a fixing device (
(not shown).

On the other hand, the photosensitive drum 1 is cleaned by a cleaning means (not shown) and is prepared for the next image formation.

The developing device 4 has a T (l image roll 8) as a developer carrier, and this developing roller 8 is arranged with a predetermined gap t from the photosensitive drum 1. About 2 to 4 m for brush development method, about 1 fi for -component contact development method, Japanese Patent Publication No. 58-5257
In the non-contact development method described in Publication No. 5 etc., 500μ~
It is about 500μ. Of course, development may be performed by pressing this developing roller against the photosensitive drum 1 with all the developer.

Around the developing roller 8, there are supply rollers 9, 10, . . . as developer supply means. +1, and these supply rollers are housed within the developer supply containers 12, 15.14. For example, cyan, magenta, and yellow developers are stored in the containers 12, 13, and 14, respectively, and when these supply rollers are fully rotated, the green color is applied to the developing roller. When desired, the supply rollers 9 and 11 are rotated, and the entire mixed developer layer that produces green is formed on the developing roller by a subtractive color mixing method of cyan+yellow→green.

Similarly, cyan + magenta → blue, magenta + yellow →
A mixed developer layer of red color can be formed on the developer roller. To make black (ha).

Six colors of cyan, magenta, and yellow are applied to the developing roller (although it is possible to separately provide a supply roller 15 and a developer container 16, store the black-like developer in this container 16, and apply it to the developing roller. Alternatively, the black color may be supplied solely to the developing roller 15.

Is the developer on the developing roller 8 used for development at a position facing the photosensitive drum 1 (development position)?

The developer not used for development is collected from the surface of the developing roller into the collection container 18 by a collection means such as a blade or brush. The collected developer is cyan, magenta,
Since it contains each color of yellow, it is a color close to black or a dot, so it may be introduced into the black developer container 16 for use. When a magnetic brush roller (magnetic roller + sleeve) is used as the black developer supply roller 15, the collection means 17 is not provided.

A magnetic brush on the roller 15 may collect residual developer on the stock roller.

A magnetic brush method may be used to apply the developer from each supply roller 9 to 11 to the developing roller 8. At this time, the developer of an unnecessary color (1 + magenta for forming green) is It is preferable to cut the supply with a scraper or provide a shutter between the supply roller and the developer roller to prevent transfer to the developer roller.

In order to easily apply the developer from the supply roller to the developing roller, a voltage with a polarity opposite to the charging polarity of the developer is applied to the developing roller to form an electric field between the two rollers, and this electric field causes the developer to be applied to the developing roller. It may also be applied to the developing roller.

When using a two-component developer, toner may be applied to the developing roller together with the carrier.

As described in UBP 4,587,497, it is also possible to apply only toner from a supply roller to a developing roller.

In order to prevent the developer in each developer container 12 to 14 and the developer of another color from heating up in the container, the developer on the supply rollers 9 to 11 does not come into contact with the developing roller 8. Alternatively, the developer may be allowed to fly from the supply roller through a gap and adhere to the developing roller. At this time, a voltage is applied to the developing roller in the direction of keeping the developer for a certain period of time, and an alternating electric field is formed between the supply roller and the developing roller as described in 6-Tokuml Publication No. 14260/1982. - The component developer may be applied to the developing roller by flying from the supply roller to the developing roller.

By supplying only one color to the developing roller 8 from each supply roller, cyan and magenta are produced.

Single color development of yellow or black can be performed.

Furthermore, as described above, by supplying the developer to the developing roller from two of the three color supply rollers 9 to 11,
Red, '#, and green colors can be obtained. Further, by changing the proportion of the developer applied from each supply roller 9 to 11 to the developing roller 8, other colors can be developed.

For this purpose, the strength of the voltage applied between each supply roller and the developing roller 8 may be changed, or the layer thickness (amount of preservative) of the developer on each supply roller may be changed using a doctor blade or the like. f(ili) may be controlled by the developer regulating members 19 to 21.

The developer may be applied from each supply roller during one rotation of the developing roller 8, or all the developer of each color may be applied every rotation.

Developed at a low position. When a two-component magnetic developer or a one-component magnetic toner is used as the developer, a non-integrity sleeve and a magnetic roller enclosed therein can be used as the developing roller. If a non-IA toner is used, a rubber roller may be used as the developing roller. During development, a contact or non-contact block method can be used depending on the current bias (direct current, alternating current, direct current + alternating current, etc.).

As described in detail above, according to the present invention, it is possible to carry out color development in which at least two or more color developers are mixed on the developer carrier, so that it is possible to easily develop a desired color within a short period of time. can be done.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an image forming apparatus to which the color developing power method of the present invention is applied. In fig. 1... Photosensitive drum 4... Developing device l'i: 8... Developing roller 9.10, 11.15... Supply roller 12.13,
14.16 represents a developer container.

Claims (1)

[Scope of Claims] A color developing method characterized by applying developers of at least two or more colors onto a developer carrier to form a mixed color developer, and developing a latent image with the mixed color developer.