JPS5938762A - Multicolor recorder - Google Patents

Abstract

PURPOSE:To eliminate the generation of color mixing in developing in a post stage, by removing the potential difference between the image part and background part generated in the development of the front stage prior to the development of the post stage. CONSTITUTION:Light is exposed to the red part of an image forming medium after said medium is unformly electrostatically charged to a value Vs1, then the potential in the exposed part decreases down to around 0V. A red toner is stuck on the above-described part where the potential decreases, resulting an increase in the potential of said part to Vt1. The grid voltage of a destaticizer which is a potential damping means is designated as Vt1, and the potentials in the image part and non-image part are unified to the value Vt1 by applying AC corona discharge. Thereafter, the potential of the image forming medium is increased up to Vs2 and light is exposed to the black part, then the potential in said part decreases down to around 0V. A balck toner is stuck on the part where said potential decreases and the potential in said part increases up to Vt2.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Technical Field of the Invention The present invention relates to a multicolor recording apparatus using an electrostatic recording method, an oil recording method, a photographic method, or the like.

(11) Recording devices using the electrostatic recording method or the electrophotographic method have a variety of recording functions, operate quietly, and generally have excellent recording quality. However, in multicolor recording devices, recording quality tends to deteriorate, and therefore, improving the recording quality has become a relatively serious technical issue.

(C) Prior Art and Problems Figure 2 shows the configuration of a conventional electrophotographic two-color recording device, in which 1 is a drum-shaped image forming medium that rotates as shown by arrow A, and 2 is an image forming medium. 1 a first charger for fully charging; 3 a first exposure device for scanning the image forming medium 1 and irradiating it with a laser beam according to a recording signal to form a first electrostatic latent image on the image forming medium 1; 4 is a first developing device that develops the first static latent image formed in the first screening device 3 using a red toner by a component magnetic brush method; 5 is a first developing device 4;
A second band width device for recharging the image forming medium 1 after being developed by the first developing device 4 scans the image forming medium 1 after being developed by the first developing device 4 according to the recording signal. A second exposure device 7 completely forms a second electrostatic latent image on the image forming medium 1 by irradiating the second electrostatic latent image with the second exposure device 6. A second developing device uses black toner to develop the image using a component magnetic brush method; 8 is a transfer device that transfers the two-color toner image formed on the image forming medium 1 onto the recording paper S; 9 is a single-unit forming device; A first remover for removing residual charges on the medium 1;
A cleaner 11 removes the residual toner on the image forming medium 1, and a discharge lamp 11 removes the charge remaining on the image forming medium 1 after the toner has been removed.

Changes in the potential on the image forming medium 1 during each process of the two-color recording apparatus configured as above will be explained with reference to FIG. Initially, it is uniformly charged to a value of Vsl by the first charger 2 ((a)). Next, exposure is performed in the first exposure device 3, and the potential of the exposed part becomes 0.
The red toner R is attached to the portion of the first developing device 4 where the drop has occurred, and the 7th position of this 1jli rises to VTI [(c) ]. Here, VBI is the iτIf of red toner R.
In order to facilitate this, the bias potential that can last for the first developing device 4 is shown.

In a two-color recording device, in order to avoid destroying the toner image formed by the first developing device 4, the following second developing device 4 is used.
In the current unit 7, a single-component toner is used, and a high-resistance type toner is used as the -component toner in order to facilitate the transfer to paper. Toner has poor developability, so to compensate for this, the second
41 η] Recharge the image forming medium 1 in the unit 5 and raise the potential of the image forming medium 1 with the VH2 switch! + ((d))
. At this time, the potential of the first developing device 41/ (therefore, the developed portion I) also rises from VTI to VTI'.

Subsequently, exposure is performed in the second exposure unit 6, and the potential of the exposed area drops to nearly O volts ((
e) ). In the second developing device 7, the black toner B is exploited in the portion where the potential drop has occurred, and the potential of this portion is V.
It rises to T2 ((f)). Here, VB2 represents a bias potential applied to the second developing device 7 in order to facilitate the attachment of the black toner B.

However, in such an apparatus, as shown in FIG. 3, when developing with black toner m in the second developing device 7, development with red toner is first performed in the first developing device 4. There is a problem in that black toner B' also adheres to portion R, resulting in a decrease in recording quality.

The reason why such a phenomenon occurs is that after development is performed in the first developing device 4, recharging is performed using the second charger 5. This is because a potential difference remains between the adhered portion and the background portion, that is, the portion to which the red toner is not adhered.

In order to solve such problems, the present inventors have developed the second @
It is proposed to eliminate the potential difference by using a scorotron equipped with a charge control function as the electric appliance 5.

However, although the above proposal is effective when the rotational speed of the image forming medium 1 is low, when the rotational speed of the image forming medium 1 is high, a large-capacity scorotron is required, making it extremely difficult to put it into practical use.

(D) Purpose of the Invention The present invention eliminates the problems in the conventional example, and eliminates the potential difference between the image area and the background area that occurs in the former stage of development prior to the latter stage of development, thereby preventing color mixture from occurring in the latter stage of development. The purpose of the present invention is to obtain a multi-color recording device that does not cause problems.

(E) Structure of the invention, that is, the multicolor recording device according to the present invention comprises a rotating image forming medium and a plurality of latent images arranged in the L1 rotation direction of the image forming medium to form a latent image on the image forming body. An image forming means, a plurality of developing means provided corresponding to each of the latent image forming means, and other developing means other than the one provided at the final stage in the rotational direction of the image forming medium among the plurality of developing means. In a multicolor recording device, a charging means is provided on the rear side VC with respect to the rotational direction of the first magazine forming medium, and a charging means is provided between the charging means and a developing means corresponding to the stage, tc attenuation means capable of attenuating the potential to an arbitrary value between the potential value of the latent image area immediately before the developing means and the potential value of the non-latent image area with respect to the rotational direction of the image forming medium; It was established.

(F) Embodiments of the Invention The gist of the present invention will be specifically explained below with reference to illustrated embodiments.

FIG. 4 shows the configuration of the first embodiment when the present invention is applied to an electrophotographic two-color recording device using red toner and black toner. Item #-1 or #-12 is a second static eliminator installed between the first developing device 4 and the second charger and used as a potential reducing stage.

FIG. 5 shows changes in the potential on the image forming medium 1 during each process of the two-color recording apparatus having such a configuration. It is charged to a value [Fig. 5-].Then, the first
In the exposure device 3, the H light is applied to the area to be recorded in red, and the voltage of the exposed area decreases to nearly 0 volts (Figure 5 (6)).
In the developing device 4, the red toner R is attached to the portion where the potential drop has occurred, and the potential of this portion rises to (B) VTI (bubble in Figure 5). Here, VBI indicates the bias potential applied to the first developing device 4 to facilitate the adhesion of the red toner R. Next, the second elimination ■1. The grid voltage of the device 12 is set to the above-mentioned VT sO value, AC corona charge removal is performed, and the potentials of both the image area and the non-image area are made equal to the value of ((1) VTI [see Figure 5]).

Thereafter, the second charger 5 charges the image forming medium 1 to increase the potential of the image forming medium 1 at VS24 (Fig. 05).

Subsequently, the second exposure section 6 exposes the area where the black recording is to be made, black toner B is attached to the exposed area, and the (1) potential of this area rises to VT2. 5th Diagram]. In addition, this is V
B2 indicates a bias potential applied to the second developing device 7 to facilitate the deposition of the black toner B.

In this way, the first developing device 4 is developed with red toner, and the second static eliminator 12 also develops the first developing device 4 with red toner.
Then, static electricity is removed up to VTI, and then charging is performed by a second charger 5, exposure is performed by a second exposure device 6, and a second developer 7 is applied.
At this time, since the potential of the image area formed by the first developing device 4 is the same as the potential of the non-image area, black toner adheres to this area. There is no fear.

FIG. 6 shows the configuration of the second embodiment of the present invention, and the difference from the first embodiment explained with reference to FIG.
An optical static eliminator 12' is used instead of the optical static eliminator 12. In the second embodiment, the light intensity is adjusted by controlling the light source voltage of the optical static eliminator 12'. The potential of the IIII image area formed by the developing device 4 and the potential of the non-image area can be set to the same value.

Although the two-color recording apparatus was described in both the first and second embodiments of Section 2, the present invention uses a second charger to transfer the potential of the image area and the potential of the non-image area after development. 5, and can be implemented even in a multicolor recording device 6 with three or more colors.

In addition, in the first embodiment, the first developing device 4 is described as one that uses red two-component magnetic brush development, and the second developing device 7 is described as one that uses black-component magnetic toner development. It is not limited by the developing method or the color of the toner. In addition, the potential after defrosting by the second 1L remover 12 or optical charge remover 12' is applied to the image area developed by the first developer 4. Although it was explained that the rectangle and position should be aligned with VTI, due to differences in the photoreceptor of the image forming medium 1, the toner size, etc., the Era 2 band '11. When charging by the device 5, a difference may occur between the potentials of the image area and the non-image area. do it.

(G) As described in the detailed description of the invention, the present invention eliminates the m-position difference between the image area and the background area prior to the subsequent development, prevents color mixing in the subsequent development, and thus improves the recording quality. can be improved.

[Brief explanation of drawings]

Figure 1 shows the configuration of a conventional multicolor recording device, Figure 2 (and Figure 3)
The figure is an explanatory diagram of the conventional example, FIG. 4 is the configuration of the first embodiment of the present invention, FIG. 5 is an explanatory diagram of the first embodiment, and FIG. 6 is the configuration of the second embodiment of the present invention: shows. In Figures 1, 4, and 6, 1 is an image forming medium, 3 and 6 are a first side light device and a second side light device, which are latent image forming means, and 4 and 7 are developing means. There are a certain first developing device and a second developing device, 5 is a device for a second band', and 12 and 12' are a second static eliminator and an optical static eliminator which are potential attenuating means.兇4 Figure (4) (h) (Rio 6 Figure 0-1 and -4 (

Claims (1)

[Claims] A rotating image forming medium, a plurality of latent image forming means arranged in the rotation direction of the image forming medium and forming a latent image on the image forming medium, and a plurality of latent image forming means provided corresponding to each of the latent image forming means. and a charging means provided on the rear side with respect to the rotational direction of the image forming medium corresponding to the other developing means other than the one provided at the final stage with respect to the rotational direction of the image forming medium among the plurality of developing means. In a multicolor recording device, the charging means is provided between the charging means and the sum corresponding to the charging means, and the imaging means is arranged to control the potential of the latent image portion immediately before the developing means with respect to the rotational direction of the image forming medium. 1. A multicolor recording device characterized by being provided with a potential attenuating means for attenuating the potential to an arbitrary value between the potential value and the potential value of the non-latent image area.