JPS58116554A - Polychromatic recording device - Google Patents

Abstract

PURPOSE:To obtain excellent polychromatic recording without increasing the size of an initial charger by providing a separating means for a developer as a front stage and a developing bias setting means capable of applying a high developing bias voltage by the surface voltage of a medium. CONSTITUTION:A photoreceptor 1 has the entire surface charged by the initial charger 2 uniformly and is then exposed to a picture corresponding to black as a section 3. Then, black toner charged positively is used to set a developing bias by a developing bias voltage setting part 5, and development is carried out by the 1st developing device 4. Then, exposure 6 of a picture corresponding to red is carried out and red toner charged positively is used to perform development through the 2nd developing device 7. The toner for the 1st development which is mixed in the 2nd developing device 7 is separated and removed by a known separating device, so recording is obtained by using the dichromatic toner free of ground staining and color mixture on the photoreceptor 1 without increasing the size of the initial charger.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an electrostatic recording device, a multicolor recording device using electrophotography, etc., particularly a developing device VcrIA.

(c) Technical Background In recent years, as electronic computers have become faster, output devices such as line printers are required to meet the following requirements.

(1) High speed printing (2) Miniaturization of the device (3) Easy maintenance (4) No noise In order to meet these demands, non-impact printing is being promoted.

In addition, the printed matter from the output device is not only used for checking the information processing results as in the past, but the results are processed, edited, tabulated, etc., and there is a tendency for the printed matter to be treated as an official document. It is required to be able to change the color of characters, symbols, figures, etc. as necessary.

0 Conventional technology and problems FIG. 1 shows a schematic diagram of a conventional two-color recording device.

Further, FIG. 2 shows the potential levels of each process for two-color recording. In FIG. 1, the entire surface of the photoreceptor 1 is uniformly charged by an initial charger 2. As shown in FIG. The potential at this time is shown in Figure 2 (
As shown in 1), the initial charging potential level is set to Vs. Next, the exposure unit 3 performs an exposure corresponding to the first color (hereinafter referred to as black) of the photoreceptor IVi. At this time, the potential of the photoreceptor 1 exposed by the exposure section 3 is shown in FIG.
), as shown in FIG.
)K, the first developing device 4 performs development gII by setting the initial charging potential level to a value slightly lower than the initial charging potential level Vs. By performing development, toner adheres to the portions from which the electric charge has been removed, as shown in FIG. 2 (3).

Next, the exposure section 6 performs a light exposure corresponding to a second color (hereinafter referred to as red). At this time, the potential Fi1jg2 of the photoreceptor 1 exposed to light by the exposure unit 6 attenuates to a voltage of V as shown in FIG. 4 (4).

Next, using a toner with a positive red charge, the developing bias voltage setting section 8 sets the developing bias voltage viz as shown in FIG.
As shown in 5), development is performed by the second developer 7 at a value slightly lower than the initial charging potential level Vs. By performing this phenomenon, red toner adheres to the portion from which the electric charge has been removed, as shown in FIG. 2 (5).

Two-color toner images are formed on the photoreceptor 1. Next, the toner image is transferred onto the recording paper lO by the transfer means 9.

9.Similar to the Indo process of ordinary electrophotographic equipment,
Heat fixation of the toner image on the recording paper 10 and cleaning process of the photoreceptor 1 11. One process is completed through the static elimination process 12.

Two-color recording can be accomplished by sequentially repeating the steps described above.

However, the conventional method has the following problems.

First, in the two-component current method, the particle size of 9 particles is 100 to 300.
(Pm) of iron powder is used as a carrier. This developer mixed with carrier and toner is fed from a mag roll (not shown) to form a spike 14 with a height of about d25 [n] on the sleeve 13 as shown in FIG. 1 to a contact depth of approximately 3 (Im).

In this way, in the two-component development method, development is performed by pressing the spike 14 made of developer against the photoreceptor 1 and rubbing it.

Therefore, if the contact depth of 1!14 of the second developing device 7 is set appropriately, the black image formed on the photoreceptor l by the first developing device 4 will completely pass through the second developing device 7. Sometimes scraped off mechanically, resulting in destruction of the black image.

Furthermore, after the black image is rubbed off, red toner may adhere to it, causing the originally black image to become a mixture of black and red.

FIG. 4 shows the relationship between the contact depth C of @2 developer 7 and the degree of development when black is used as the 8g1 developer and red is used as the second developer. As the contact depth l of the second developer gII 7 increases, the density of the red image increases, but the density of the black image decreases.

This is because the black image is mechanically removed by the second fA111 unit 7, and after being removed, the red toner of the second developer unit 7 adheres, causing color mixing.

For this reason, in the conventional apparatus, the contact depth # of the second developer 7 is made small to prevent destruction and color mixing of the toner image formed on the photoreceptor 1 by the first developer 4. However, reducing this contact depth -r is the second
The developed density could not be obtained sufficiently.

This means that density unevenness occurs. Therefore, MZgL
In order to obtain sufficient developed density in the imager 7 as well.

A large latent flaw strength, that is, an initial charging potential level Vs on the photoreceptor l must be set high as shown in FIG.

However, in order to raise this initial charging potential level Vs lr, a high voltage power supply for the initial charger 2#'i is required, which increases the cost. Furthermore, increasing the initial charging potential level has the disadvantage that the amount of ozone generated during discharge increases. Further, this method still has the problem of color mixing of toners, similar to the example shown in FIG.

(G) Object of the Invention In view of the above-mentioned drawbacks, an object of the present invention is to provide a multi-color recording device that performs development using a two-component development method, which can produce good multi-color recording without requiring large latent image strength. The purpose is to obtain a color record.

(G) Embodiments of the Invention The present invention will be explained in detail with reference to the drawings. Here, the present invention will be explained using a two-color recording device.

FIG. 6 shows a schematic diagram of a two-color recording apparatus according to the present invention.

Figure @7 shows the potential levels of each process for two-color recording in the two-color recording device in Figure AIG6.

In the figure, first, the entire surface of the photoreceptor is uniformly charged by the initial charger 2 of IFi. At this time, the potential t-@7 is set to the initial charging surface potential level Vs (6000) as shown in FIG. 1 (1). Next (on the photoreceptor IFi, exposure of an image corresponding to black is performed by the exposure section 3. At this time, the potential of the photoreceptor 1 exposed by the exposure section 3 is approximately Attenuates to 0 (V).

Thereafter, using a black toner with a positive charge, the developing bias voltage setting section 5 sets the developing bias voltage level to 1 s (60
0(V))jRayaJi6i value(VBI°=700(
V)), and the first developing device 4 performs development. By carrying out this first development, toner adheres to the background portion as well as the portion from which the charge has been removed, as shown in FIG. 7(3)K.

Next, the exposure section 6 performs exposure of an image corresponding to red. At this time, the upper part of the photoreceptor 1 exposed by the exposure unit 6 is shown in FIG. 7 (4).
YOrV). At this time, toner is also layered on the background part due to the W, 1 problem, but it is at an age that does not pose a problem for the second foggy light.

Next, using toner with a positive red charge, the developing bias voltage setting section 8 sets the developing bias voltage vi+z to fj
As shown in FIG. 1E7 (5), development is performed by the second developer 7 at a value slightly lower than the surface potential level Vs.

At this time, the toner attached to the background area due to @1 development is
The potential on the photoreceptor 1 is 6oo(v) or more.

Since the developing bias electron of the @2 developer 7 is 500 (V), the electrons are mixed into the @2 developer 7. The toner from the first development mixed into the second developer 7 is removed by a conventional separation device V.
It is separated and removed from ζ. Therefore, a two-color toner image without background smear or color mixture can be obtained on the photoreceptor 1. As explained above, according to the present invention, the initial charger does not need to be large, that is, a high-voltage power source is not required. Excellent two-color recording can be obtained without the need for turbulence, and costs can be significantly reduced. Furthermore, since the initial charging potential level can be lowered, ozone generation tt can be reduced.

*Although a two-color recording device has been described in the above embodiment, the present invention is not limited to this, and can be applied to a multi-color recording device having a plurality of developing devices using a two-component development method. May be used.

In addition, as shown in Figure @6, in a multicolor recording apparatus having a plurality of developing devices, a developing bias voltage cutting means 13 that can apply both a developing bias voltage higher than the medium surface potential and a developing bias voltage lower than the medium surface potential to each developing device. If you attach them and configure them so that they can each be driven independently.

It is possible to print in a wide variety of color combinations, and also to print in a single color.

(J Effects of the Invention According to the present invention, in a multicolor recording device using a two-component development method as a developing means, the initial charger does not have to be enlarged.

That is, good two-color recording can be obtained without requiring a high pressure source. Furthermore, since the initial charge level can be reduced, the total amount of ozone generated can be reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a conventional multicolor recording device, Fig. 2 is a diagram showing potential levels of each process of the multicolor printing device shown in Fig. FIG. 4 is a diagram showing the relationship between contact depth σ and developed density. FIG. 5 is an explanatory diagram of the electric power level of a conventional multicolor recording device. FIG. 6 is a diagram showing the power level of a conventional multicolor recording device. FIG. 7, which is a schematic diagram of the recording apparatus, is a diagram showing potential levels of each process of the multicolor recording apparatus shown in FIG. 6. In the figure, 1 is a photoreceptor, and 2t-1 is an initial charger. 3.6 front end, 4 and 7 developing device, 5.8 developing bias voltage setting section, 9 transfer means, 10# paper, 11 cleaning process, 12i' static elimination process, 13 developing It is a great bias voltage switching means. 3 sticky 0/234 i san*, no S [γm] 甐4 目悌5 color 1 ((5) 稟2 蜆image( 前 Study paper q (, pu) 11th stock() 1.'e,) (
4th batch - 21st police station infected with the virus

Claims (1)

[Claims] (1) Charging means for uniformly charging the entire surface of the latent image forming medium. At least two latent image forming means for forming a kit image on the latent image forming medium, and a developing device provided corresponding to each of the latent image forming means, and developing the latent images on the latent image forming medium with different colors and the same polarity. In a multicolor recording device, the developing means includes a separating means for separating and removing the developer used in the preceding developing means, which is mixed into the developing means, and a final stage. A multi-color recording apparatus characterized in that the parts other than the developing means further include a developing bias setting means capable of applying a developing bias voltage higher than the surface voltage of the medium given by the charging means. (2. In the multicolor recording apparatus according to claim 1, the developing means other than the final stage developing means has a developing bias voltage higher than the charging means and a developing bias voltage lower than the surface potential of the medium. 1. A multicolor recording device comprising a developing bias voltage switching means that can selectively apply a developing bias voltage.