JPS6050553A - Multicolor electronic recording method - Google Patents

Abstract

PURPOSE:To obtain a good multicolor image having no color mixture irrespective of a difference of electrostatic capacity of a photosensitive body by setting an initial electrostatic charge to the potential by which a latent image intensity required for development is obtained, eliminating only a part of a charge by one latent image forming means, and forming a latent image. CONSTITUTION:A photosensitive body is charged uniformly to the potential VS by which a latent image intensity required for development is obtained, by an initial charge, subsequently, a part of the charge is eliminated so as to become the potential VK by exposure corresponding to red by an exposing means, a latent image 21 is formed, and a red image 22 is formed by a developing machine by using a red toner. Next, the charge quantity is reduced in the recharging process by a recharger, and the potential on the toner image 22 can be made uniform to the potential VS irrespective of a difference of an electrostatic capacity of the photosensitive body. Subsequently, a latent image 23 and a black toner image 24 are formed by the second exposing means and the developing machine, by which the images 22, 24 of two colors having no color mixture can be obtained on the photosensitive body.

Description

Detailed Description of the Invention (al) Technical Field of the Invention The present invention relates to a multicolor electronic recording method in a multicolor electronic recording device using an electrophotographic recording method, an electrostatic recording method, etc.
In particular, the present invention relates to a method that can clearly record multicolor information without color mixture.

Background of the Technology In recent years, with the diversification of information, there has been a demand for multicolor electronic recording devices that can record information in two or more colors, and various devices and recording methods have been proposed.

tc+ Prior Art and Problems FIG. 1 is a schematic diagram for explaining a multicolor electronic recording device, and to simplify the explanation of the prior art, the recording method will be explained using a two-color electrophotographic recording device. . Figures 2 to 7 show the image on the photoreceptor in each step when forming two-color toner images on a latent image forming medium (hereinafter referred to as photoreceptor) using the two-color electrophotographic recording apparatus shown in Figure 1. FIG. 3 is a diagram showing potential states.

As shown in these schematic diagrams and potential state diagrams,
In a conventional two-color electrophotographic recording device, an initial charger 3 such as a charging corotron charges a photoreceptor 1, in which a photoconductive layer 2 made of selenium (Se) or the like is laminated on a conductive layer, as shown in FIG. is uniformly charged to a potential νS. Next, the photoreceptor 1
For example, 0FT (Optical Fiber T
The first exposure means 4 consisting of an ultraviolet light source (e.g.
As shown in the figure, a latent image 21 corresponding to the first color information attenuated to approximately OV is formed. Next, the latent image 21 is developed using, for example, a two-component developer containing positively charged red toner.
As shown in FIG. 4, an appropriate developing bias voltage VB is set by the first developing device 5 of the component magnetic brush developing method and the first developing bias voltage applying device 6 so as not to cause fogging in the background area.
is applied to perform development and form a toner image 22 of the first color. At this time, the potential on the first color toner image 22 is vtl
becomes. Next, before performing negative exposure corresponding to the 2' color information by the second exposure means 8, the photoreceptor 1 is charged as shown in FIG. The potential Vs is recharged to a potential Vsl at which a latent image strength necessary to obtain a sufficient toner image density in second development of a one-component magnetic toner development method to be described later is obtained. At this time, the grid voltage of the recharger 7 is set to vsl
By doing so, the potential Vt on the first color toner image 22 also becomes the same potential as the recharging potential Vs1 of the photoreceptor 1. Thereafter, the second exposure means 8 performs negative exposure corresponding to the second color information on the photoreceptor 1, and the potential of the exposed portion is reduced to approximately Ov as shown in FIG.
A latent image 23 is formed corresponding to the color information of the corresponding ? VI
As shown in FIG. 7, a developing bias voltage vB2 equivalent to the recharging potential νs1 of the photoreceptor 1 is applied to the image 23 by the second developing bias voltage applying device 1o as shown in FIG. 7, and a one-component magnetic developer (black) is used. The toner image 24 of the second color is formed by performing development using the second developing device 9. Two-color toner images 22. of red and black are thus formed on the photoreceptor 1.
24 is transferred onto the recording paper 12 by the transfer device 11,
The image is fixed by thermocompression bonding or the like in a fixing section (not shown).

- The toner remaining on the photoconductor 1 is neutralized by the static eliminator 13 and cleaned and removed by the cleaner 14. Further, all charges on the surface of the photoreceptor 1 are removed by an optical charge eliminator 15, and a new recording cycle begins.

In the above recording method, the charging potential Vs of the photoreceptor 1 and the first color toner image (red toner image) 2 are changed by recharging.
The reason why the potentials Vt and 2 on the first color toner image 2 which have already been formed during development to form the second color toner image (black toner image) 24 is equal to the recharging potential Vsl.
This is to prevent the developer of the second development from adhering to the second developer and causing color mixture. Incidentally, when the recharging process is omitted in the above recording method, a predetermined developing bias voltage V is applied to the latent image 21 portion corresponding to the first color information, as shown in FIG.
B.

There is a potential difference between the potential Vt on the first color toner image 22 formed by applying the voltage and the charging potential Vs of the photoreceptor l. With such a potential difference, as shown in FIG. 9, negative exposure corresponding to the second color information is performed on the photoreceptor 1, and the potential of the exposed portion is reduced to approximately Ov to obtain the second color information. A latent image 23 corresponding to the 1-component magnetic toner (
A toner image 24 of a second color is formed by second development using a toner image (black).
, on the first color toner image 22 already formed due to the potential difference (VB2-Vt, ),
The developer 24a of the second development adheres and color mixture occurs.

Therefore, in the conventional two-color recording method described above, color mixing is prevented by the above-described recharging process, and good two-color recording is made possible.

However, in the above-mentioned conventional two-color electrophotographic recording method, there are cases where the latent image strength required to obtain a toner information image with good color density is large, or when the first development and second development
If there is a large difference in the respective latent image strengths required for development, the potential Vt on the first color toner image 22 and the charged potential Vs of the photoreceptor 1 will not match even if recharging is performed. Due to this, color mixing occurs in the first color toner image 22 already formed during the second development, and a good two-color toner image cannot be obtained. According to studies conducted by the present inventors, this phenomenon of defects becomes more noticeable when the capacitance of the photoreceptor is large.

Ultimately, these problems are caused by an increase in the amount of charge required to obtain a predetermined charging potential.

ρ: Volume charge density of one layer (image) of toner, dt: ) one layer (image)
thickness of image), ε0: permittivity of vacuum, εrtL=average dielectric constant of one layer of toner (image), Cp: capacitance of photoreceptor, g:
The electric potential vt on the first color toner image 22 is given by the following equation when the charge density on the photoreceptor is taken as the charge density. That is, νt+='A(ρdt/εoεrn)+ρdt/Cp+
g /CpIn the above formula, 'A(ρdt/εoEr
The first term, indicated by t), is the potential of the toner layer (image) itself, and the second term, indicated by ρdt/Cp, is the potential of the photoreceptor due to the toner charge, and is further indicated by g/Cp. Third
The term is the potential of the photoreceptor due to surface charge.

When a photoreceptor with a large capacitance Cp is used for a given amount of charging, the potentials of the second and third terms in the above relational expression become smaller, while the potential of the first term, that is, the toner layer (image), becomes smaller. The applied voltage increases.

If the voltage becomes too large, an air discharge will occur between the surface of the toner layer (image) and the surface of the photoreceptor, causing the potential of the toner layer (image) to change to the potential of the photoreceptor. ” It has been found that it is difficult to align the two levels. 1st
Regarding the two-color electrophotographic recording device shown in the figure, the first development is two-component magnetic brush development (necessary latent image strength 300 to 400).
0 V or more), and one-component magnetic toner development (required latent image strength 700 to BOOVIJ or above) was used for the second development, but in this case, the photoreceptor capacitance Cp was approximately 1 μF/n? If it exceeds this, a problem of potential non-uniformity after recharging will occur. Note that the value of the capacitance Cp of the photoreceptor at which potential non-uniformity occurs after recharging is not absolute, and varies depending on the dielectric constant ε of the toner used.

Td+ Purpose of the Invention In view of the above-mentioned drawbacks of the conventional art, the present invention has been made to provide a method for forming multicolor toner images without being affected by differences in capacitance of photoreceptors that form multicolor toner images.
Potential vt on the already formed first color tree-image
1 and the charged potential Vs of the photoreceptor can be easily aligned to a potential that will provide sufficient toner image density in the next development, thereby providing a new multicolor electronic recording that provides good multicolor recording without color mixture. The purpose is to provide a method.

(e) Structure and purpose of the invention, according to the prior invention, is to erase the electric charge in a portion corresponding to color information on an initially charged latent image forming medium by means of latent image forming means such as light irradiation or electric discharge. forming a latent image, converting the latent image into an image by a developing means, and then recharging the surface of the latent image forming medium on which the toner image has been formed;
A process of forming a latent image by erasing the charge in a portion corresponding to the next color information on the recharged latent image forming medium by next light irradiation or latent image forming means such as electric discharge; In an electronic recording method in which multicolor information is recorded by sequentially repeating the process of converting an image into a toner image by a developing means, the initial charging potential is
The potential is the same as or higher than the potential required to obtain the latent image intensity, which is necessary for the development step where the VI image intensity is maximized, and each of the steps is to form a latent image on the initially charged latent image forming medium. Among the latent image forming means, at least one latent image forming means forms a latent image by removing only a part of the electrical charge held by the latent image forming medium without removing all of it. A pair of multicolor electronic recording methods (J
This is achieved by j.

(fl Embodiments of the Invention Below, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 10 to 15 show potential states on the photoreceptor during each recording process when an embodiment of the multicolor electronic recording method according to the present invention is applied to the two-color electrophotographic recording apparatus shown in FIG. 1. FIG.

An embodiment of the present invention will be explained using the configuration diagram of a two-color electrophotographic recording apparatus shown in FIG. It is uniformly charged to a potential νS that provides the latent image strength necessary for one-component magnetic toner development, which is the final development. FIG. 16 shows the recharging characteristics of the recording apparatus of this example. This is a case where the potential difference between the potential on the first color toner image before recharging and the potential on the photoreceptor 1 in the background area is 300V. The potential change on the photoreceptor in the background area is 100
It can be seen that when recharging is performed to exceed V, the potential on the first color toner image is no longer aligned with the potential on the photoreceptor 1 in the background area. For this reason, the initial charging potential is set to 1 in advance so that when the potential on the photoreceptor 1 is increased by recharging, the potential increase will be 100 V or less until the latent image strength required for one-component magnetic toner development is obtained. The potential Vs is set to obtain the latent image strength necessary for component magnetic toner development.

Next, on the photoreceptor 1, for example, an OFT (Optica
The first exposure means 4 consisting of a Fiber'Tube) performs negative exposure corresponding to the first color information by controlling the exposure amount so that the potential of the exposed portion changes as shown in FIG.
Potential Vk at which the latent image strength required for the first development described below is obtained
A part of the charges on the photoreceptor 1 is removed so that the latent image 21 corresponding to the first color information is formed. Next, the latent image 21 is developed, for example, by a first developer 5 of a magnetic brush development method using a two-component developer containing positively charged red toner and a first development bias voltage applicator 6, as shown in FIG. A suitable developing bias potential VB is applied so as not to cause fogging in the background portion, and development is performed to form a toner image 22 of the first color. Next, recharging is performed by a recharging device 7 consisting of a corotron with grid control. Since the potential on the photoreceptor 1 before recharging is the potential Vs at which the latent image strength necessary for one-component magnetic toner development is obtained, there is no need to increase the potential of this portion by recharging. Therefore, from the results shown in FIG. 16, the potential Vt on the first color toner image 22 can be made equal to the potential Vs as shown in FIG. 13.

Thereafter, a second exposure means 8 is applied onto the photoreceptor 1.
A latent image 23 corresponding to the second color information is formed by performing negative exposure corresponding to the second color information, and the potential of the exposed portion is reduced to approximately Ov as shown in FIG. To,
As shown in FIG. 15, the second developing bias voltage applicator 10
A developing bias voltage VB2 equivalent to the charging potential Vs of the photoconductor 1 is applied, and development is performed by a second developing device 9 using one-component magnetic toner (black) to form a toner image 24 of a second color. By doing so, toner images 22 and 24 of two colors (red and black) without color mixture can be obtained on the photoreceptor 1. Therefore, as in the conventional case, the first and second color toner images 22 and 24 formed on the photoreceptor 1 are transferred onto the recording paper 10 in the transfer section 8, and fixed by thermocompression bonding or the like in the fixing section 9. This makes it possible to clearly record two-color information without color mixture.

The above explanation has been made according to FIGS. 1 and 10 to 16, but in reality, each potential condition is set in consideration of the dark decay of the potential on the photoreceptor 1, leakage voltage during development, etc. There is a need. The specific potential conditions in this example are as follows. The capacitance Cp of photoreceptor 1 is 1.3μF
/ rri. The initial charging potential Vs is 1000V, which is higher than the potential 800V at which the latent image strength required for one-component development is obtained, taking into account dark decay, leakage voltage during development, etc.
Set to a certain degree. The potential Vk after the first exposure is approximately 400V, and the first development bias voltage νB1 is set to 800V to perform development. At this time, the potential on the photoreceptor 1 is attenuated to about 800 V due to leakage voltage during development. When the potential conditions were set in this way, the potential on the first color toner image could be set to 5oov by recharging, and a good two-color image without color mixture etc. was obtained. Incidentally, in the above embodiment, an example of a two-color electrophotographic recording method has been described to simplify the explanation, but the present invention is not limited to this example, and the present invention is not limited to this example. Needless to say, the present invention can also be applied to a recording method of a recording device, and similar effects can be obtained. Furthermore, the present invention is not limited to multicolor recording using the electrophotographic recording method as explained in the above embodiments, but can also be applied to multicolor recording using an electrostatic recording method using a latent image forming means such as a pin electrode. Needless to say, it is applicable.

fgl Effects of the Invention As is clear from the above explanation, according to the multicolor electronic recording method according to the present invention, the initial charging potential for the photoreceptor is set by the developing means that maximizes the required latent image strength among the developing means. By setting the potential at or above the potential that provides the required latent image strength, and reducing the amount of recharging in the recharging process, regardless of the difference in electrostatic plasticity of the photoreceptor, the potential that has already been formed at the time of recharging can be reduced. The potential of the toner image can be easily adjusted to the same potential level as the charged potential of the photoreceptor.

As a result, it has the advantage that good multicolor recording without color mixture can be obtained, which is extremely advantageous in practice. Therefore, excellent effects can be achieved when applied to this type of electrophotographic recording system or electrostatic recording system multicolor electronic recording apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining a multicolor electronic recording device using a two-color electronic recording device using an electrophotographic recording method, and FIGS. FIGS. 10 to 15 are diagrams illustrating potential states when forming a two-color toner image on a forming medium (hereinafter referred to as a photoreceptor), and illustrate an embodiment of the multicolor electronic recording method according to the present invention. Fig. 1 shows a potential state diagram on the photoreceptor during each recording process applied to the two-color electrophotographic recording device, and Fig. 16 shows potential changes on the photoreceptor during recharging and the photoreceptor after recharging. FIG. 3 is a diagram showing the relationship between the potential difference between the potential on the top and the potential on the toner image. In the drawing, 21 is a latent image corresponding to the first color information;
2 is the toner image of the first color, 23 is the latent image corresponding to the second color information, 24 is the toner image of the second color, Vs is the initial charging potential of the photoreceptor, vBI, vB2 are the developing bias voltages, V
k indicates the potential of the exposed area after the first exposure to obtain the required latent image strength in the first development, and Vt indicates the potential on the toner image 22 of the first color. 8th factor Figure 9 m 10 [W Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 @ Figure 16 100, 200 300

Claims (3)

[Claims] (1) A latent image forming medium that has been initially charged.Second, a latent image is formed by erasing the charge in a portion corresponding to color information by a latent image forming means, and the latent image is converted into a toner image by a developing means. rear,
A process of recharging the surface of the latent image forming medium on which the toner image has been formed, and erasing the electric charge of a portion corresponding to the next color information on the recharged latent image forming medium by the next latent image forming means. In this electronic recording method in which multicolor information is recorded by sequentially repeating the process of forming a latent image using a developing means, and the process of converting the latent image into a toner image using a developing means, the above-mentioned initial charging potential is sequentially repeated. The potential is the same as or higher than the potential at which the latent image strength required for the developing step in which the latent image strength is maximized in the developing step performed, and the initial charging is performed on the latent image forming medium. Among the latent image forming means that form a latent image, at least one latent image forming means removes only a part of the charge held by the latent image forming medium without removing all of it. A multicolor electronic recording method characterized by forming an image. (2) The latent image forming means is a light irradiation means, and by controlling the light energy, only a part of the electrical charge on the latent image forming medium is removed to form the latent image. A multicolor electronic recording method according to claim (1). (3) The latent image forming means is a discharging means, and by controlling the amount of ions or electrons generated by discharge, only a part of the electrical charge on the latent image forming medium is removed to form a latent image. Claim No. 1 (1) characterized in that
) The multicolor electronic recording method described in section 2.