JPS59116763A - multicolor recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (A) Technical Field of the Invention The present invention relates to a multicolor recording device such as an electrophotographic recording device or an electrostatic recording device, and particularly relates to a recharging process for obtaining good multicolor recording. This is related to the improvement of.

(B) Prior Art and Problems FIG. 1 is a diagram for explaining a conventional two-color recording device. FIG. 2 is a diagram showing the potential level on the photoreceptor of the two-color recording apparatus shown in FIG.

In the figure, an initial charger 2 uniformly charges a photoreceptor 1, which is an image forming medium. The potential at this time is set to <Vs+ as shown in FIG. 2 (1). Next, the exposure means 3 exposes both images corresponding to the first color (color A) as shown in FIG. At this time, the potential of the exposed portion is attenuated to approximately 0 [V]. After that, the first image is pressed. This is the second
As shown in FIG. 1 (3), a two-component magnetic brush developer 4 using a developer with positive toner charge is used for the first color (color A), and the developing bias voltage is set to a value slightly lower than the developing bias voltage Vs 1 k Vs ]. , and perform development. Then, Figure 2 (3
), toner adheres to the portion from which the charge has been removed. Next, as shown in FIG. 2(4), the recharging device 5 performs a complete recharging process to increase the potential on the photoreceptor 1 and decrease the unsaturated potential ΔV caused by the first development. This is the second
This is because, in one-component magnetic toner development used for development, the required latent image strength to obtain a sufficiently high-density recording is greater than that of two-component magnetic brush development. This is to prevent magnetic toner from adhering to the end section of the tube. The potential on the photoreceptor obtained by recharging is defined as vs2. Next, the exposure means 6 exposes an image corresponding to the second color (color B) as shown in FIG. 2(5). At this time as well, the potential of the exposed area is attenuated to approximately O (V). After that, second development is performed. Development bias voltage used VB 2
Development is performed by setting the f Vs to approximately the same value as 2.

Then, as shown in FIG. 2(6), toner adheres to the portion from which the charge has been removed, and a two-color toner image of A color and B color is formed on the photoreceptor 1. Thereafter, the toner image is transferred onto recording paper 9 by transfer device 8 . Next, one process is completed through the fixing of the toner image, the static elimination process 10, and the cleaning process 11, as in a normal electrophotographic process. This method provides a good 2
Color recording can be done.

For simplicity, a two-color recording device has been described as an example, but in such a device, when developing with eight-color toner is performed by the one-component magnetic toner developer 7, the two-component magnetic brush imager 4 first develops the image using eight-color toner. The eight color toners also adhere to the area where the A-color toner has been developed, resulting in color mixing and deterioration of recording quality.

The reason why this phenomenon occurs is that even when recharging is performed by the recharging device 5 in the recharging process, such as when using a photoreceptor with a large capacitance, the unsaturated potential Δ■ in the first phenomenon is sufficiently reduced. This is to prevent it from happening.

In order to overcome these drawbacks, in the past, as shown in Figure 3, after the first development, the entire surface is irradiated to attenuate the potential of the non-image area and reduce the potential difference between the image area and the non-image area, and then re-irradiation is performed. The present inventors have proposed a charging method. Although good two-color recording can be obtained with this method, it has the disadvantage that it adds a step of irradiating the entire surface, making the process complicated.

(C) Object of the Invention In view of the above-mentioned conventional drawbacks, the object of the present invention is to eliminate the potential difference between the image area and the background area (unsaturated potential ΔV)'f by a simplified process and to create a multi-color system that does not cause color mixture. The purpose is to provide a recording device.

[F]) Structure of the invention and object of the invention is to provide a rotating image forming medium, a plurality of latent image forming means arranged in the rotational direction of the image forming medium and forming a latent image on the image forming medium; A plurality of developing means provided corresponding to each latent image forming means, and a plurality of developing means provided corresponding to each latent image forming means, and a plurality of developing means provided corresponding to the other developing means except the one provided at the final stage with respect to the rotational direction of the image forming medium. To provide a multicolor recording device comprising a recharging means provided on the rear side of a forming medium, using a scorotron as the recharging means, and recharging in a corona discharge region accompanied by light emission. achieved by.

■ Examples of the invention Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In the present invention, a scorotron is used as a recharging device. FIG. 4 shows the structure of this scorotron. A metal wire with a diameter of about 50 to 150 μm is provided as the corona wire 12 inside the grounded metal case 14.
A high voltage of 91 (■) is applied. Also, a plurality of metal wires having a pitch of about 1 to 3 inches and a diameter of 50 to 150 μm are provided as grid wires 13 in the opening of the metal case 14.

The voltage (MV) applied to the grid voltage is Apply a voltage that is approximately the same as the desired charging potential.

Corona discharge starts when the voltage (HV) applied to the corona wire 12 is about 4 kV, and it becomes possible to charge the photoreceptor 1. When the corona applied voltage (Hv) reaches about 7 to 9 kV, corona discharge becomes active and a large amount of corona ions are generated, and a light emission phenomenon appears around the corona wire 120.

However, even if a large amount of corona ions are generated, the controllability of the grid wire 13 makes it possible to charge the photoreceptor 1 to an arbitrary potential. When a recharging device that utilizes such a discharge state is used in the recharging process of a two-color printer shown in Fig. 1, the luminescence phenomenon that occurs around the corona wire will occur as shown in Fig. 3 (
It plays the role of irradiating the entire surface as shown in 2), and charges to a predetermined potential while suppressing the rise in potential of the background area after the first development. As a result, there is no need to provide a special step of irradiating the entire surface as in the conventional case, and uniform angular charging can be obtained by simply setting the corona applied voltage to a higher voltage.

A 5e-Te drum is used as the body 1, and a second uniform charging of about 500V is performed by the initial charger 2. Next, negative exposure corresponding to color A is performed to form a latent image, and then @1 development, that is, reversal development using a two-component magnetic brush developer 4 using positive polarity toner is performed in red. The bias voltage applied to the developing device 4 is 300 to 400 cm. As a result, a red first image is formed on the photoreceptor 1. At this time, the unsaturated potential ΔV due to the first development is about 200 μ.

Next, for recharging 5, use a scorotron to apply 7 to 9 kV to the corona wire and 800 to 100 O to the grid wire.
Approximately V is applied. A bluish light is generated around the corona wire, and this light increases the overall potential of the photoreceptor 1 by 800% while suppressing the increase in the potential of the background area after the first development.
Charge it to about V. As a result, the unsaturated potential due to the first development can be suppressed to 50V or less. Next, negative exposure corresponding to B color is performed to form a latent image. Thereafter, a one-component magnetic toner developer 7 is used to carry out reversal development of black magnetic toner. The bias voltage applied to the developing device 7 is approximately 800V. Through the above steps, it is possible to form good two-color toner images of red and black on the photoreceptor.

The luminescence phenomenon in corona discharge2 can be seen in both positive corona discharge and negative corona discharge, but positive corona discharge has a more uniform luminescence distribution9, while negative corona discharge has multiple luminescent lights on the corona wire. Points occur and the emission distribution is non-uniform.

In this example, the case of positive corona discharge was described, but
The distance between the corona wire and the photoreceptor in the corona charger is 1
Since they are separated by about 0 to 20 mrg, the light amount distribution on the photoreceptor becomes uniform even with negative corona discharge, and almost the same effect as in the case of positive corona discharge can be obtained.

However, in this embodiment, the ij: two-color recording device has been described, but the present invention is one in which the potential of the image area after the first development and the potential of the background area are made equal to each other before the second exposure, and recharging is performed. and
This method can also be implemented in a multicolor recording device that uses three or more colors.

In this embodiment, the first developing device 4 is developed by red two-component magnetic brush development, and the second developing device 7
Although the description has been made on the assumption that black-component magnetic toner development is used, the present invention is not limited to these development methods or toner combinations.

Effects of the Invention As explained in detail above, according to the present invention, since recharging is performed in a discharge area accompanied by a light emission phenomenon using a scorotron, the potential difference (unsaturated potential ΔV) between the image area and the background area is reduced. Uniform charging can be performed while removing. Therefore, there is an effect that good multicolor recording without color mixing can be obtained with a simplified process.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a two-color recording device, FIG. 2M is a diagram showing the potential level on the photoreceptor of the two-color recording device shown in FIG. 1, and FIG. 3 is a diagram for explaining conventional recharging control. , FIG. 4 is a schematic diagram of a scorotron, which is a recharger used in the present invention. In the drawings, 1 is a photoreceptor which is an image forming medium, 5 is a recharger, 12 is a corona wire, 13 is a grid wire, 1
4 is a metal case.

Claims (1)

[Claims] A rotating image forming medium, a plurality of latent image forming means arranged in the rotational 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 recharging means provided on the rear side 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. A scorotron is used as the recharging means.
1. A multicolor recording device characterized by performing recharging in a corona discharge region accompanied by light emission.