JPH0425856A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a small-sized device in which the occurrence of fogging and faulty transfer are prevented by directly transferring photoconductive toner left on a conductive drum to a paper to be transferred. CONSTITUTION:The conductive drum 22 is uniformly coated with the photoconductive toner 21, and the toner is electrostatically charged to be negative by an electrostatic charger 24. Thereafter, the toner is irradiated with light 25 synchronizing with the signal of an image or a character, etc., so that an electrostatic latent image is formed on the toner 21. At such a time, the surface potential of the toner 26 which is not irradiated with the light is not changed but the toner 27 which is irradiated with the light is polarized and the surface charge thereof is eliminated. Then, a separation means 28 makes an electrostatic charger 29 generate the ion of reverse charge to the charge of the toner 26, so that the toner is scattered from the drum 22 and sucked by a suction pump 30. Meanwhile, the toner 27 left on the drum is transferred to the transfer paper 33 and fixed by a fixing roller 35.

Description

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

[Conventional technology]

FIG. 3 is a block diagram showing an example of a conventional image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 59-212860. (3a) and (3b) are the fixing rollers, (4) is the photoconductive toner stored in the toner hopper (5), (6) is the paper feed roller, and (7) is the developing roller. Toner regulation blade facing drum (1), (8
) is a lens which is an oval member of the light irradiation means, (9) is a fixing roller (3g), and (3b) is a transfer paper passing between, <1
0), <112 is *1 device, (I2) is a cleaning device! It is.

Next, the above image forming device! Explain the operation. Developing drum (1), transfer drum (2), fixing roller (3a) <3b
) in the direction of the arrow shown, the photoconductive toner (
4) is the developing drum (1) by the toner regulating blade (7).
) is coated in a thin layer on the surface of the A light image is irradiated onto this coated thin layer toner via a lens (8), and a latent image is formed on the thin layer toner.
A latent image is formed as the difference between polarized toner) and non-polarized toner]. Thereafter, by corona charging the transfer drum (2) near the developing drum (1) with a charger (10), only the polarized toner on the surface of the developing drum (1) is transferred to the transfer drum (2) by electrostatic attraction. The images are transferred and visualized. The toner formed into an m image on the surface of the transfer drum (2) is further transferred to a fixing roller (3a) by a charger (11).
The image is transferred to the transfer paper (9) via the transfer paper (9).

Furthermore, in Japanese Patent Application Laid-Open No. 53-103739, FIG.
Image forming methods as shown in a) to (e) are shown.

In FIG. 4, (13) is a conductive support, (14) is a transparent substrate, (15) is a transparent electrode, (16) is a photoconductive toner layer, (17) is a charger, (18) is an exposure device, (19) is a transfer paper, and 20) is a charger.

The operating method is as follows.

First, a photoconductive toner layer (16) is uniformly formed on the surface of a conductive support (13) consisting of a transparent electrode (15) laminated on a transparent substrate (14) (see FIG. 4, 1). . Next, after the toner layer (16) is uniformly charged by the charger (17) (see FIG. 4(b)), the toner layer (16) is exposed (18) so that it is hidden on the toner layer (16). form an image (
(See FIG. 4(c)), and during this image exposure, weak uniform exposure may be performed from the back surface of the conductive support (13) (see FIG. 4(d)). Next, transfer the toner from the unexposed areas to the transfer paper (
19) to obtain a recorded matter (No. 4).
(See figure (e)).

[Problem to be solved by the invention]

In image forming apparatuses using conventional photoconductive toner, the fourth
As shown in the figure, only the non-irradiated toner was transferred to the transfer paper (19) in a state where the light-irradiated toner and the non-irradiated toner were mixed, so the light-irradiated toner was also transferred at the same time.
There was a problem that fogging occurred.

In addition, in order to avoid this, the apparatus shown in FIG. 3 first transfers only the toner to be transferred onto a transfer drum (2), etc., and then transfers it onto a transfer paper (9) as shown in FIG. However, in this device, in order to separate the light irradiated toner and unirradiated toner on the developing drum (1), the transfer drum <2
), the device becomes larger by attaching the transfer drum (2), and the fixing roller (3a), (
3b), the fixing roller (3g), (
3b) There was a problem with the cap, in which toner remained attached to the cap and the toner also adhered to the transfer drum (2).

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus that does not cause fogging or transfer defects and can be made smaller.

C Means for Solving the Problem] The present invention provides a conductive drum on which photoconductive toner is uniformly adhered, a charger that charges the photoconductive toner, and a charged photoconductive toner. A light irradiation means for selectively irradiating light to form an electrostatic latent image on a conductive drum, and a photoconductive toner whose charge has been removed by light irradiation or a photoconductive toner whose charge remains due to not being irradiated with light. and a toner separating means for separating the toner from the conductive drum.

[For production]

In this invention, the photoconductive toner left on the conductive drum is directly transferred to the transfer paper by the toner separating means.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, (21) is a photoconductive toner, (22) is a conductive drum, and (23) is a photoconductive toner whose tip end faces the conductive drum (22). A blade (Z4) is a charger provided opposite to the conductive drum (23), (25) is light irradiated from a light irradiation means (not shown), and (26) is a charger provided on the conductive drum (22). Toner that has not been irradiated with light, (27) is the toner that has been irradiated with light on the conductive drum (22), and (28) is an ion that is provided opposite to the conductive drum (22) and has an opposite charge to that of the toner that has not been irradiated with light (26). A toner separation means (30) is provided in the suction pipe (31) to separate the unirradiated toner (26) from the conductive drum (22) by the electrostatic force generated by the charger (29) that generates the toner. A suction pump for collecting the toner (26) into the developing device (32), (33) is the transfer paper, (3
4) is a charger, and (35) is a fixing roller.

FIG. 2 shows an enlarged view of the toner separating means (28) in FIG. 1. The toner separating means (Z8) consists of a charger (29), a toner charging section, and a suction section. A filter (36) is installed between them to prevent the light-guiding toner (21) from scattering or adhering to the charged portion, and is made of a thin film material such as plastic or paper.

Next, the operation of the image forming apparatus having the above configuration will be explained. After a photoconductive toner (21) is uniformly coated in a thin layer on a conductive drum (22) by a blade (23), it is negatively charged by a charger (24 tons).

Thereafter, a photoconductive toner (21) coated with a thin layer of light (25) from a light irradiation means synchronized with signals of images, characters, etc.
irradiation to form an electrostatic latent image on the photoconductive toner (21). At this time, the unirradiated toner (26)
Although the surface charge of the toner (27) remains unchanged, the light-irradiated toner (27) undergoes polarization and loses its surface charge. In this state, toner (2
6) and (27) are conveyed to toner separation means (28). Here, the unirradiated toner (
26) is generated, and the unirradiated toner (26) is separated from the conductive drum (22) and scattered. At this time, the scattered light is caused by the bow absorption force of the suction pump (30). The unirradiated toner (26) is sucked and collected into the developing device (32) via the suction pipe (31) and used again for recording.

On the other hand, the light-irradiated toner (27), which has no charge remaining on the conductive drum (22), is conveyed to the transfer portion of the transfer paper (33). Here, the light irradiated toner (27) is transferred to the transfer paper (3) by the charge generated from the charger (34).
3) and is fixed via a fixing roller (35) to form an image on the transfer paper (33). In Figure 1, the initial charge on the photoconductive toner (21) is negative, the toner (26) that has not been irradiated with light becomes positive when it is removed by suction, and the charge is negative when transferred to the transfer paper (33). Although it depends on the polarity, the opposite polarity is also possible depending on the charging characteristics of the photoconductive toner.

In the above embodiment, the case where the light irradiated toner (27) is transferred to the transfer paper (33) is shown (in the case of a printer), but on the contrary, when the non-light irradiated toner is transferred (in the case of a copying machine) ), it is possible to separate the light-irradiated and light-unirradiated toners using a charger that generates a charge of the same polarity as the toner that was initially charged by the toner separating means (28) (in the case of light-irradiated toner). The toner loses its electric charge and becomes easily peeled off from the substrate, while the unirradiated toner is repelled by the charger and remains attached to the substrate without being easily peeled off).

〔Effect of the invention〕

As explained above, according to the image forming apparatus of the present invention, the photoconductive l-toner left on the conductive drum is directly transferred to the transfer paper.

This has the advantage that a high-resolution image without fogging etc. can be formed on the transfer paper, and the apparatus can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an enlarged view of the main parts of FIG. 1, FIG. 3 is a block diagram showing an example of a conventional image forming apparatus, and FIG. 4(a) -(e) are process diagrams showing an example of a conventional image forming method. In the figure, (2]) is photoconductive toner, (22) is a conductive drum, (25) is light, and (26) is unirradiated toner (
27) is a light irradiation toner, (28) is a toner separation means, (
33) is the transfer paper. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] a conductive drum on which a photoconductive toner is uniformly adhered; a charger that charges the photoconductive toner; and a charger that selectively irradiates the charged photoconductive toner with light onto the conductive drum. a light irradiation means for forming an electrostatic latent image on the conductive drum; and a toner separation means for separating the photoconductive toner from which the electric charge has been removed by the light irradiation or the photoconductive toner from which the electric charge remains due to the non-irradiation from the conductive drum. An image forming apparatus characterized in that the photoconductive toner remaining on the conductive drum is directly transferred onto the transfer paper by the toner separating means.