JPH01223474A - Image forming device - Google Patents

Abstract

PURPOSE:To develop a multicolor image by using one developing device by using photoconductive toner which is photosensitive to specific wavelength areas, removing the light conductive toner which has lost electrostatical charge by the exposure of the specific wavelengths and repeating the development of electrostatic latent images. CONSTITUTION:The three color light conductive toner 1 which has three different photosensitive areas respectively is made to adhere uniformly to a first conductive base body 4 and electrostatically charged by a corona electrostatical charging equipment 3. The charged toner is transcribed to a second conductive base body 5 by means of impressing a bias voltage between the base body 5 and the base body 4 so as not to form the double or more layers on the base body 5. Then, a selective exposure 6 other than the exposure of the photosensitive wavelength of the photoconductive toner of one color is carried out on the base body 5, and the toner which has lost the electrostatical charge is removed using an aspirator 7. Next, it is transcribed against the base body 5 while the bias voltage is impressed to a third donductive base body 8. Then, the latent image of a photosensitive body 10 which received an image exposure 11 is developed, and the undeveloped toner is recovered by a blade 14. The toner developed on the photosensitive body 10 is transcribed on a paper 12 on a transcription drum 9. The same process is repeated for other two colors, and the three color transcription is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus using photoconductive toner.

[Conventional technology]

Conventional image forming apparatuses used the same number of developing machines as there were colors to be developed, but by using photoconductive toner, image forming apparatuses have been able to reduce the number of developing machines to one. ,was suggested.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, if the pie-sumi pressure is increased during development, separation will be insufficient and density will not be achieved.Since photoconductive toner with low resistance is used during development, the transfer rate will be low during transfer. There was a problem that the image density decreased significantly and the image density could not be counted sufficiently.

The present invention is intended to solve these problems, and its purpose is to provide an image forming apparatus that can perform multicolor development using one developer gAa and can form images without reducing image density. It's there to provide.

[Means to solve the problem]

The image forming apparatus of the present invention is an image forming apparatus using a photoconductive toner, in which (a) the photoconductive toner that is sensitive to a specific wavelength range is uniformly charged; (b) the photoconductive toner is charged uniformly; Charging step (c) Applying a bias voltage between the first conductive substrate and the second conductive substrate to charge the photoconductive toner so that the photoconductive toner does not form two or more layers on the second conductive substrate. (d) Step of exposing the photoconductive toner on the second conductive substrate to light of a specific wavelength; (e) Step of removing the photoconductive toner that has lost its charge; (f) Step of removing the photoconductive toner that has lost its charge; (g) applying a bias voltage between the second conductive substrate and the first conductive substrate and transferring the photoconductive toner onto the third conductive substrate; (h) Collecting the undeveloped photoconductive toner (i) Transferring the toner on the developing surface to a transfer member ( j)
It is characterized by a step of fixing the toner on the transfer body.

[For production]

According to the above configuration of the present invention, by exposing one color of photoconductive toner to light at a wavelength other than the sensitive wavelength using the photoconductive toner, it is possible to leave only the charge of the -color toner and eliminate the other charges. Can be done. Further, by setting the speed of the third conductive substrate faster than that of the second conductive substrate, it is possible to increase the toner concentration on the developing surface.

Hereinafter, the present invention will be explained in detail with reference to Examples.

〔Example〕

FIG. 1 is a schematic diagram of an image forming apparatus in an embodiment of the present invention. Photoconductive toners 1 of three colors, each having a different sensitivity range, are uniformly deposited on a first conductive substrate 4 from a toner hopper 2.Next, the photoconductive toners are uniformly charged by a corona charger 3. . This is transferred to the second conductive substrate 5.
By applying a bias voltage between the photoconductive toner 1 and the first conductive substrate 4, the photoconductive toner 1 charged to the second conductive substrate 5 becomes 1
Exposure 6 to light at a wavelength other than the sensitivity wavelength of the - color photoconductive toner is performed on the second conductive group #, 5 to be transferred so that the electrostatic charge is eliminated, and suction 7, etc. The photoconductive toner which has lost its mirror image with the second conductive substrate 5 is removed by the means of
While applying a bias to the conductive substrate 8, the conductive substrate 8 is made to face the second conductive substrate 5 so as to have a positive relative speed.
Next, the photoreceptor 10 and the third conductive group # exposed to @ exposure 11
The toner developed on the photoreceptor 10 is transferred to the top 12 on the transfer roll 9. Further, after the toner that has not been transferred is scraped off by the blade 14, the photoreceptor is charged by the corona charger 15.
The surface potential is made uniform.

When the development of one color's worth of toner is completed, the applied bias is reversed and the toner on the third conductive substrate 8 is collected to the first conductive substrate, and the charge of another two colors disappears. The same process is carried out sequentially using exposure 6,
When the tricolor bone toner is transferred onto the paper, the paper 12 passes through the fixing roll 13, the toner is fixed onto the paper, and printing is completed.

Zn0 (manufactured by Sakai Chemical Co., Ltd.) was used as the photoconductive toner,
As sensitizers, methylene blue and phthalic anhydride are adsorbed for the cyan toner, eosin Y and phthalic anhydride for the magenta toner, and Solar Pure Yellow G and phthalic anhydride for the yellow toner. PBMA (Mitsubishi Rayon, Ba2O3
> A polyethylene wax charge control agent (Moshoku Kasei, FCNlooIN) crushed to a diameter of 1 μm, and colorants such as phthalocyanine for Shiman, rhodamine B lake for magenta, and benzidine derivatives for yellow in weight ratios. The mixture was mixed at a ratio of 10:10:10:1:1, toluene was added, and the mixture was dispersed and melted using an ultrasonic disperser so that the solid content was 20%.

Next, this fractional solution was spray-dried to produce a spherical photoconductive toner having an average particle size of 10 μm.

Next, an image was formed using this toner according to the steps shown in FIG. The first conductive drum 4 has a surface roughness of 3 μm
An aluminum plate was used, and a rubber blade was pressed against it with appropriate pressure so that the toner was applied in about a layer. The charging current was -200 .mu.m, and it was charged to -15 .mu.c/g. +200 with the first conductive drum 4 grounded
A second conductive drum 5 made of aluminum to which V was applied was brought into contact, and the negatively charged photoconductive toner was transferred in a single layer.

Next, filtered white light of a wavelength that reacts with the photoconductive toner of the desired color is irradiated, and at the same time, a suction device is used to absorb and remove the toner that has lost its mirror image power due to the electrical charge.

Next, a third conductive drum 8 made of aluminum to which a voltage of +500 cm was applied is brought into contact with the second conductive drum, and the photoconductive toner that has not lost its charge is transferred. This third conductive drum is brought into contact with the exposed photoreceptor, and +700V is applied to the photoreceptor. Toner was developed in the areas that received image exposure. Furthermore, +5.2 KV of corona charging electricity was applied from the back side of the transfer roll on which the paper was placed, and the toner was transferred to the paper.

The above steps were performed in the order of yellow, magenta, and cyan, and the toner on the transfer drum was conveyed to a fixing device and fixed on paper. As a result, a clear image with sufficient image density and no blurring or color mixing due to toner scattering was obtained.

[Example 2] FIG. 2 shows another example of the re-image forming method of the present invention. Unlike Example 1, a conductive magnetic sleeve 17 is used instead of the first conductive drum, and the Frictional IF electricity is generated between the magnetic carrier 16 and the photoconductive toner.

In this case, the first electrically conductive substrate is transferred to the second electrically conductive substrate by applying a bias voltage between the magnetic sleeve and the second electrically conductive substrate. It was transferred onto the substrate in a single layer. The subsequent steps are the same as those in the first embodiment.

When the above image forming method was carried out in the same manner as in Example 1 using the three types of photoconductive toners prepared in Example 1, sufficient image density was obtained, and the image density was thought to be due to toner scattering. A clear image was obtained without any disturbance or color mixture.

〔Effect of the invention〕

In an image forming apparatus using photoconductive toner, (a) uniformly charging the photoconductive toner that is sensitive to a specific wavelength range, (b) charging the photoconductive toner, and (c) photoconductivity. Step (d) of applying a bias voltage between the first conductive substrate and the second conductive substrate to transfer the toner onto the second conductive substrate under conditions that the toner does not form two or more layers; (e) removing the photoconductive toner that has lost its charge; (f) exposing the photoconductive toner on the second conductive substrate to light of a specific wavelength; (g) transferring the photoconductive toner onto the third conductive substrate by applying a bias voltage between the conductive substrates; (h) Collecting the undeveloped photoconductive toner (i) Transferring the toner on the developing surface to a transfer member (j)
By consisting of the process of fixing the toner on the transfer body,
It is now possible to selectively separate and develop only one color of toner from a developer containing a mixture of three color toners without causing toner scattering, and the resulting image has sufficient density and is free of toner. Clear images without color mixing or blurring caused by scattering can be obtained. This makes it possible to make the device and photoreceptor smaller than when developing using developing devices for each of the three colors, and it has a significant impact on reducing the initial cost of image forming devices such as page printers. You can expect good results.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing an image forming apparatus according to a second embodiment of the present invention. 1... Photoconductive toner 2... Toner hopper 3... Corona charger 4... First conductive substrate 5... Second conductive substrate 6... Selective exposure 7... - Toner suction device 8...Third conductive substrate 9...Transfer drum 10...Photoreceptor 11...Image exposure 12...Paper 13...Fixing roll 14...Cleaning blade 15 ... Corona charger 16 ... Conductive magnetic carrier 17 ... Conductive magnetic sleeve and above Applicant: Seiko Epson Corporation Representative Patent attorney: Tsutomu Mogami (and one other person), 1. 5.1

Claims (1)

[Scope of Claims] In an image forming apparatus using photoconductive toner, (a) a step of uniformly charging the photoconductive toner that is sensitive to a specific wavelength range (b) a step of charging the photoconductive toner (c) Applying a bias voltage between the first conductive substrate and the second conductive substrate, the photoconductive toner is transferred onto the second conductive substrate under conditions that no more than two layers are formed. (d) exposing the photoconductive toner on the second conductive substrate to light of a specific wavelength; (e) removing the photoconductive toner that has lost its charge; and (f) removing the photoconductive toner that has lost its charge. applying a bias voltage between the conductive substrate and the first conductive substrate to transfer the photoconductive toner onto the third conductive substrate; (g) transferring the photoconductive toner on the third conductive substrate; (h) Collecting the undeveloped photoconductive toner (i) Transferring the toner on the developing surface to a transfer member (j) Transfer An image forming apparatus comprising a step of fixing toner on a body.