JPS60166967A - Polychromatic recording device - Google Patents

Abstract

PURPOSE:To evade color mixture even when recording is repeated and obtain excellent polychromatic print stably by making the toner surface of a preliminary developing means except a final developing stage rugged, and increasing sticking force to a photosensitive body. CONSTITUTION:An electrostatic charger, the 1st exposing part and developing part, a recharger, and the 2nd exposing part and developing part are arrayed successively at the outer periphery of the photosensitive body; and the same magnetic material is used for the carriers used in and the 1st and the 2nd developing parts the 1st and the 2nd toner particles 24b and 34b are made of nonmagnetic insulators having the same mean grain size, but the surface of the 1st toner 24b is made finely rugged. Therefore, electrostatic force, mechanical frictional force, etc., caused by an uneven microelectric field produced at the periphery of the toner 24b are applier intensely and the sticking force to the photosensitive body 1 becomes larger; and a toner image which is formed firstly is not separated from a photosensitive layer 11a and no different color toner enters the developing device, so excellent polychromatic recording is carried out without color mixture.

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a multicolor recording device using an electrophotographic recording method, an electrostatic recording method, etc., and in particular, color mixing does not occur even when recording is performed continuously. The present invention relates to a multicolor recording device.

(b) With the diversification of technological background information, there is a growing demand for multicolor output information. Multicolor recording is no exception in the field of recording devices using electrophotographic recording methods or electrostatic recording methods.

In such a multicolor recording apparatus, when recording is performed by sequentially repeating the steps of latent image formation and development, multicolor recording is performed in which the latent image is made wet and visible using toners of different colors in each development step. In such a recording apparatus, consideration must be given to W1M color mixture, in which toners of different colors mix with each other, making it impossible to record in the original color.

(C) Prior Art and Problems The phenomenon of color mixing will be explained by taking a two-color recording device that employs an electrophotographic recording method as an example.

0 In electrophotographic recording, the surface of the photosensitive drum is charged uniformly,
forming a latent surface corresponding to an image of a first color with a laser beam;
Toner of the first color is supplied from the developing part to form a toner image of color @l. A multicolor toner image is obtained by sequentially performing these steps a plurality of times, and multicolor recording is performed by transferring this multicolor toner image onto recording paper.

In such a multicolor recording device, if we pay attention to the @2 developing section, the second developing section supplies toner of the second color to the photosensitive layer on which a toner image of the toner of the first color has already been formed. That will happen. At this time, a portion of the toner constituting the first color toner image is peeled off and mixed into the second developing section. If you repeat this result recording many times for a long time, gIJ2
The toner of the first color accumulates in the developer in the developing section of
A problem arises in that the development in the second developing section causes color mixture. If the first color toner and $2 color toner have charges of different polarities, it is relatively easy to separate them using the difference in polarity, but if they have the same polarity, Since it is difficult to separate the developer, conventionally, when color mixture occurs, all the developer is replaced. In this way, the occurrence of color mixture shortens the life of the developer (d).Objective of the InventionThe purpose of the present invention is to provide a system that can stably obtain good multicolor printing without causing mixed color printing even after long-term repeated recording. It provides:

(e) Structure of the Invention The present invention utilizes the effect that the formation of toner has a great influence on the adhesion force with the photosensitive layer. The force by which the toner adheres to the photosensitive layer includes a mirror image force due to the charge of the toner, an electrostatic force due to a non-uniform minute electric field generated around the toner, a mechanical adhesion force, and a 7-ante Awarska force.

If the shape of the toner is close to spherical, the electrostatic force due to the non-uniform micro-electric field, the mechanical adhesion force, υ van der Waalska, are small, but if the toner surface is uneven, these forces are large and the photosensitive The adhesion with the layer increases.

The present invention takes advantage of this phenomenon, and is a multicolor recording device that uses toner with an uneven surface in a developing means preceding the final developing means.

('') Embodiment of the Invention Structure of this Embodiment FIG. 1 is a schematic diagram of a two-color color recording device that employs an electrophotographic recording method.The recording device in FIG. 1 includes a photosensitive drum 11, a charger 12a, First exposure section 18B, @1 developing section 14a, recharger 12b, second exposure section 18b
, hX2 developing section 14b transfer device 15. Static eliminator 16. It consists of a cleaner 17 and a static elimination lamp 18. FIG. 2 shows the detailed structure of the developing section 14a, and FIG. 8 shows the detailed structure of the developing section 14b.

In FIG. 2, the developing section 14B is connected to the housing 21. Developing roller 22 as a developer carrier. It consists of a doctor blade 28. The developing roller 22 includes a magnet roller 22a and a sleeve 22b made of a non-magnetic material (for example, aluminum).

The developer 24 is a two-component developer consisting of a carrier 24fl and a toner 24b.

The mechanical structure of FIG. 8 is the same as that of FIG. 2. The respective carriers 24&, 84& used in the first developing section 14a and the second developing section 14b are the same, and have a particle size of 5 to 5.
A magnetic material having a resistivity of 101 to 1016 Ω·1 per 50 μm is used. Further, the first and second toners 24b, 8
4b are the same in that they both have an average particle size of 5 to 20 μm and are non-magnetic insulators, but in addition to being different in color, at least the first toner 24b has fine irregularities of about 0.1 to 1 μm on its surface. Use one with

The photosensitive drum 11 serving as the operational latent image forming medium of this embodiment has a photosensitive layer 11a on its surface, and rotates at a constant speed in the direction of the arrow. Charger 12
a is charged by supplying charge to the photosensitive layer 11a. In the first exposure section tga, the photosensitive layer is irradiated with laser light or the like to form a latent image corresponding to the image of the fourth color on the photosensitive layer. In FIG. 2, the sleeve 22b includes a magnet roller 221L, and the sleeve 22b includes a magnet roller 221L.
When a rotates in the direction of the arrow, the developer 24 attached to its surface is conveyed in the direction of the arrow. The developer 2
The thickness of layer 4 is determined by the doctor blade 23. The developing roller 22 and the photosensitive drum 11 are
and the developer layer are opposed to each other to maintain contact. Although not shown, a developing bias withstand pressure is applied between the developing roller 22 and the photosensitive drum 11.

The toner used in the first developing section has a particle size of 5 to 20 μW.
It has an uneven surface. FIG. 4 shows how toner with an uneven surface and spherical toner adhere to a photoreceptor.

Toner with an uneven surface has a strong electrostatic force due to a non-uniform micro electric field generated around the toner, mechanical friction vibration force, and strong adhesion to the photoreceptor.

After the first toner image is formed, the potential of the first toner image area is raised to near the back area potential by the recharging device 12b. Next, as in the case of the first image, negative exposure with laser light or the like is performed to destroy the potential of the exposed portion and form a second latent image.

Next, development is performed in the developing section 14b.
The toner 84b in b may be a toner with an uneven surface or a conventional toner without basting. Also, one-component magnetic toner that does not use a carrier is also good.

Even if the second development is performed on the photoreceptor on which the first toner image has been formed in this way, the previously formed toner image has a strong adhesion to the photosensitive Ji911a, so it is peeled off from the photosensitive layer and the second It will not get mixed into the developing device. FIG. 5 shows the potential on the photosensitive drum in each step.

First, the surface of the photosensitive jU 11 B is charged to a potential ■s by the charger 12& (FIG. 5(a)). A latent image corresponding to the first color image is formed by the first exposure section 13& (FIG. 5(b)). This electrostatic latent image is visualized by supplying first, for example, blue toner 24b by the first developing section 14a set to the developing bias voltage VBi to form a toner image (FIG. 5(C)). The toner used here is a toner having an uneven surface according to the present invention.

Further, the potential of the first color image area is raised by the recharger 12b (FIG. 5(d)), and the second exposure area 1
A latent image is formed by the toner 841 of a second color (for example, red) by the second developing section 14b whose developing bias 12 pressure is set to VB2 (FIG. 5(e)). Figure 5 (f)).

Through these steps, two-color toner images are formed on the surface of the photosensitive drum. This two-color toner image is transferred to the recording paper 19 by the transfer device 15, and is fixed to the recording paper by passing through a fixing section (not shown).

After the transfer has been completed, the photosensitive drum 11 is removed by a static eliminator 16. Cleaner 17. The residual toner on the surface is removed by the removal lamp 18, the potential becomes Ov, and it is used repeatedly.

Example of how to make the toner of the present invention A conventional toner with a particle size of 5 to 20 μm71 and a particle size of 0.
Powder of carbon or the like of about 1 to 1 μm is mixed and stirred in an atmosphere at a temperature at which the toner begins to soften. As a result, fine particles adhere to the toner surface, forming irregularities on the surface. If the ambient temperature is lowered and classification is performed, 0.1 to 1
It is possible to create a toner having a particle size of 5 to 20 μJ with micrometer irregularities.

Modifications Although the present invention has been described with respect to a multicolor recording device using electrophotography, it is also possible to use a bottle electrode on an electrostatic recording medium.
It goes without saying that the present invention can also be applied to a method in which a latent image is formed using ion flow control or the like and multicolor recording is performed.

(g) Effects of the Invention According to the present invention, by using a toner with an uneven coating on the surface, the adhesion force between the photoreceptor and the toner increases, and the second
Even if development is performed multiple times, such as with 1% 8, the toner will not be peeled off from the photoreceptor.

Therefore, a color mixing phenomenon such as mixing of different color toner into the developing device and causing IM failure does not occur. Therefore, good multicolor recording without color mixture can be performed for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of a two-color recording apparatus using an electrophotographic recording method, and FIGS. 2 and 8 are 1'L 1. Second
FIG. 4 is an explanatory diagram showing the outline of the developing section, FIG. 4 is a diagram showing the appearance of toner on the photosensitive layer, and FIG. It is a position map. In the figure, 11 is a photosensitive drum, 11a is (surface light LJ), 121m is a charger, 1211 is a recharging device, 181L, 1gb is an exposure section, 14a and 14-b are the first and second developing sections, 22 are the developing roller, 24.84 are the first and second developers, respectively, 24a l 34 & are the first and second carriers, respectively, 24b is the uneven toner of the present invention @1, and 84b is the The second thing that can be done is
toner. Z: Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] a latent image forming medium, a charging means for supplying electric charge to the medium, a latent image forming medium forming an electrostatic latent image corresponding to an image to be recorded on the latent image forming medium, and the electrostatic latent image. It is equipped with a plurality of developing means that visualize the toner image by supplying toner to the recording paper, and a transfer means that transfers the visualized toner image onto recording paper, and the latent image is formed by sequentially repeating the charging, latent image formation, and development multiple times. In a multicolor recording device that forms a multicolor toner image on a medium and then transfers the multicolor toner image all at once onto the recording sheet, at least the toner in the upstream developing means other than the final developing means is deposited on the surface of the medium. A multicolor recording device characterized in that it is provided with irregularities that increase adhesion to a latent image forming medium.