JPS58147754A - Method and device for forming multicolor image - Google Patents

Abstract

PURPOSE:To form a tri-color image at a high speed, and also to make a device small- sized, by executing primary charging of fixed polarity and the first whole surface exposure, subsequently, executing secondary charging which is opposite in polarity to the primary charging, and simultaneously, executing the exposure by laser light which is varied to 4 steps as to its quantity of light, in accordance with tri-color image information. CONSTITUTION:On a photosensitive drum 10 which forms a photoconductive layer 12 and a transparent insulating layer 13 in order on a conductive base body 11, first of all, the first electrifier 14 and the first lamp 15 are operated at the same time. Subsequently, onto the photosensitive drum 10, secondary charging which is opposite in polarity to the primary charging is executed by the second electrifier 16, simultaneously, the exposure is executed by laser light 21 whose light quantity is varied to 4 steps, and after scanning in accordiance with tri-color image information 19 of blue, red and black, a blue image and a black image are developed by the first developing device 22. Subsequently, by a lamp 23, the second whole surface exposure is executed, and a red image is developed by the second developing device 24. A tri-color image formed on the photosensitive drum 10 is transferred onto recording paper by an electrifier 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multicolor image forming method and apparatus that can form a three-color image in a simple process.

[Technical background of the invention and its problems]

Conventionally, there is a laser printer as a non-impact printer using electrophotographic technology. This is to fv4 a laser beam according to image information, and then deflect it to form a two-dimensional image on a photoreceptor in the form of pixel resolution, and then obtain a recorded image using a known electrophotographic process. . In this case, since the two-dimensional image information is divided into pixels, it is easy to combine different types of information, delete information, or change the size of each horizontal character. However, since the recorded image is printed in the same color, tl'f
information becomes difficult to identify.

In addition, it is thought that there will be a strong demand for format updates, distinctions between mark information and document information, and distinctions between additional information and supplementary information and main information in future administrative processes. Therefore, it is thought that printers capable of identifying different types of information will become very important in the future.

In order to meet these demands, we have expanded the technology of two-color printers and Kishi-Moro Sheep printers, and by analogy, we have improved the process of transferring the OT visual image to the recording paper on the transfer drum each time an image is formed using the first K transfer drum. 31! ! First, it is possible to obtain a three-color image by repeating the process once. This is a three-color image forming process using a so-called three-rotation drum/three-transfer method.

In this case, +1 for each color! II image formation is exactly the same as a conventional laser printer, but because the image formation is performed in three rotations of the drum, the printing speed is 173 times higher than that of a monochrome printer. It has the disadvantage that the mechanism is very amk due to the extremely high precision required. On the other hand, the second method is to form a latent image on the photoreceptor drum by exposing it to IIINIgI light of % color and to develop it one color at a time. This method is because the 11I7 images are formed in one rotation of the drum.

The printing speed may be the same as a monochrome laser printer, or the laser scanning system for exposure (laser light source, optical system,
A device, deflector, etc.) must be installed in three sets.
The equipment has become complicated, bulky, and expensive.
Not suitable for office auto J-V Yon III equipment.

[Purpose of the invention]

The purpose of the present invention is to quickly create three-color ImgI in a simple process.
It is an object of the present invention to provide a multicolor image forming method and apparatus which can form a multicolor image and can be realized in a simple, compact and inexpensive manner.

[Summary of the invention]

In the present invention, a photoreceptor is used, which is formed by sequentially forming a photoconductive layer and a transparent insulating layer on a conductive substrate, and this is subjected to primary charging with a constant polarity and first overall exposure. After that, secondary charging is performed with the polarity opposite to that of the primary charging, and at the same time, the first color is Then, the surfaces of the photoreceptors in the image forming section for the second color are brought to potentials of opposite polarity, and at the same time, the surfaces of the photoreceptors in the image forming section for the third color are brought to zero potential to develop the first and second color images. The method is characterized in that a second entire surface exposure is performed to set the surface of the photoreceptor in the third color image forming section to a potential of the same polarity as the primary charging, and to develop a third color image.

〔Effect of the invention〕

According to the present invention, one rotation of the photoreceptor drum 1
Since a three-color image can be obtained, the th1&formation speed is comparable to that of a single-color printer. In addition, because the 3-horizontal lightless operation is performed using an l-beam laser light whose light intensity changes in 4 steps according to the image information of the 3 colors, the scale is not a scale that simplifies the process; Only one set of running threads is required. Therefore, the configuration of the printer becomes simple and compact, and the cost can be reduced. (3
This is a configuration diagram of a color printer), and Figure 2 shows its 1111g.
FIG. 3 is a process diagram illustrating the I formation process.

In the figure, numeral 10 is a photosensitive drum having a three-layer structure in which a photoconductive layer 12 and a transparent layer 13 are sequentially formed on a conductive substrate 11, and the conductive substrate IJ is kept at zero potential. do.

Three colors - When forming an image, first #! The first charger 14 and the first lamp 16 are operated at the same time.
As shown, the photosensitive drum 10 is primarily charged, for example to a negative polarity, and at the same time a first full-surface exposure is performed. At this time, since the photoconductive layer 12 is made conductive by the entire surface exposure, positive charges are injected into the photoconductive layer 12 from the conductive substrate 11 and distributed at the interface between the photoconductive layer 12 and the transparent insulating layer 13.

Next, the second charger 16 charges the photoreceptor drum 10 with 1
While secondary charging is performed with a polarity opposite to that of the secondary charging, that is, with a positive polarity, one photosensitive drum 10 is exposed at the same time by Radhe light 21 in which the photoelectric charge is divided into four stages of Kf. That is, the laser light source 17
The laser light emitted from the laser beam is modulated by the optical modulator 18 so that the amount of light changes in four steps according to the three-color image information 19 of, for example, blue, red, and black, and further deflected by the deflector 20. The photosensitive drum 10 is scanned in the width direction. In addition.

If the laser light source 17 can be directly modulated, the optical modulator 18 is not necessary. Here, the laser beam 21 of the variable 1111vk has the largest amount of light corresponding to, for example, a colorless (white) part, followed by blue (first color) thl? , red (second color) image, and M (third color) image, the amount of light is assumed to decrease sequentially. In this way, as shown in FIG. 2(b) K, the blue image forming section 131. At E, the photoconductive layer 12 becomes completely conductive, so that no charge exists at the interface between the conductive group @11 and the photoconductive layer 12, and a negative potential is exhibited on the surface of the transparent insulating layer 130. In addition, in the red image forming portion RkJD, the photoconductive layer 12 is made semiconductive, so that undischarged charges remain at the interface between the conductive substrate 11 and the photoconductive layer 12, and zero charges appear on the surface of the transparent insulating layer 130. Indicates potential. Further, in the black image forming portion BLK, the potential changes depending on the amount of secondary charge on the surface of the transparent insulating layer 130 and is reversed to a positive potential. On the other hand, since the colorless part WHT is exposed very strongly, the photoreceptor drum IO
K has no charge at all and has zero potential on the surface of the transparent insulating layer 130. Therefore, in this state, #! from the first developing device XZK! Figure 2 (C) A blue image and a black image are developed using a positively charged blue toner and a negatively charged colorless toner as in K Ho.

Next, a second entire surface exposure is performed on the photoreceptor drum 10 from the second lamp 231fC, and the surface of the transparent insulating layer 130 in the red 1lii image forming portion RED is brought to a negative potential in the order shown in FIG. 2(d). do. The charge distribution of the red image forming part RED at this time is exactly the same as that of the blue image forming part BLB before the blue image forming part iii1gl and the black image forming part 0.
In this state, a red image is developed by the second developing device 24 using positively charged red toner as shown in FIG. 2(e).

In this way, three colors am consisting of red, blue, and heat are formed on the photoreceptor drum 10. On the surface of the transparent insulating layer 130 on the photoreceptor drum 10 in the above process,
FIG. 3 shows the time course of , corresponding to FIG. 2.

The three colors IIR* formed on the photoreceptor drum 10 are processed by a third charger 25 of positive polarity to align the polarities of the toners of each color, and then a fourth charger of negative polarity having the opposite polarity. 2
6 onto the recording paper 27, and is further fixed by a fixing device (not shown) to form a three-color print. On the other hand, the surface of the photoreceptor drum 10 after the transfer passes over a static elimination station 28 and a cleaning station 29 to be neutralized and cleaned in preparation for the next three-color th image formation.

Next, a more specific embodiment of the present invention will be described. A/
A 50 μm 8e-Te photoconductive layer 12 was formed on the conductive substrate 11, and a 20 μm microphone (trade name of HORIETHYLE/TEREPHTHALATE) was formed thereon as a transparent insulating layer 13, and three steps were performed. A surface potential of -1000 V was formed on the photosensitive drum 10. Next, while secondary charging is performed by applying +6 KV to the second charger 16, a semiconductor laser (g2Qnm, 15 mw) is used to charge the red IliiiI forming part with 5 erg/l, and the blue image forming part with 16 erg/l. /cd, colorless part is 30er
Due to the exposure at g/cd, a latent image with a surface potential of 0 V in the red image forming area and the colorless area, -300 V in the blue film forming area, and +300 V in the black image forming area is formed on the photoreceptor drum J.

formed on top. In this state, the developing bias voltage was set to 0 VIC in the first developing device 22, and development was performed using a blue toner of positive polarity and a colorless toner of negative polarity. Next, a second overall exposure is performed using a white light source, which is the second lamp 23, at an exposure amount of 5/11x*m to set the surface potential of the red image forming area to -aoov, and in this state, the second developing device 24
The developing bias voltage was set to OV, and development was carried out using positive polarity red toner. As a result, a three-color image consisting of red, blue, and black was obtained on the photoreceptor drum 10. Next, apply +5V to the third charger 26 to align the polarities of the three colors of toner to positive polarity, and then apply −5V to the fourth charger 26.
, 5 KV was applied onto plain paper to obtain a three-color print.

The present invention can be implemented with various modifications as follows. That is, in the example, the photoconductive layer 12 was assumed to be an sc system and the primary charge was set to negative polarity, but the photoconductive layer 12 was
When selecting ds, opc, etc., the primary charge should be positive, and the 2nd charge should be positive.
It is possible to make the next charge negative polarity, and various photoconductive layers can be used.

In addition, in the example, the first current 1#! Sometimes two-color images are developed at the same time using two-color toners of different polarities, but
You may perform each separately. Furthermore, the charge distribution of the red, blue, and black image forming portions is not restricted in any way and can be freely selected. Furthermore, by appropriately changing the exposure amount of the laser beam and selecting an appropriate developer, it is possible to print an elliptical output form in the desired color, so it is possible to extract only the necessary information. Color printing, single-color printing, two-color printing in which different types of information are output in the same color, single-color printing, etc. are easily possible.

As described above, according to the present invention, not only the process is simple and the device configuration is simple and compact, but also it is possible to respond to various changes in function by changing the exposure amount. It is possible to meet the needs of users who may have various functional requirements without requiring any major changes to the hardware, and it is possible to provide a printer that is optimal as an office automation device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a multicolor image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a process diagram showing the image forming process.
FIG. 3 is a diagram showing the time course of the surface potential of the photosensitive drum in the same example. 10... Photosensitive drum, 11... Conductive substrate, 12
... Photoconductive layer, 13 ... Transparent insulating layer, 14 ... First charger, 15 ... First lamp, 16 ... Second
Charger, 17... Laser light source, 18... Light modulator, 19... Three-color image information, 20... Deflector, 21...
...Laser light, 22...First developer, 23...Second rung, 24...WJ2 developer, 25...Third charger, 26...Fourth Charger, 27... Kiryoku paper, 28... Static elimination station, 29... Cleaning stage seal. Applicant's Patent Attorney Takehiko Suzue Figure 1 16 2v! J

Claims (2)

[Claims] (1) A photoconductive layer and a transparent insulating layer on a conductive substrate,
On the photoconductor, which is formed sequentially, primary charging with a constant electric charge and full exposure of WJl are performed, followed by secondary charging with a polarity opposite to that of the primary charging, and at the same time three-color image information is generated. Since exposure is performed using a laser beam whose light intensity changes in four steps according to the amount of light, the surface of the photoreceptor of the t7j41 color and the second color conceit formation area is set to potentials with opposite polarities, and at the same time, the third color The first and second color images are developed with the surface of the photoreceptor in the eclipse forming area at zero potential, and then a second full-scale exposure is performed to primary charge the surface of the photoreceptor in the erect formation area of the third color. A multicolor image forming method characterized by developing an image of 183 colors as potentials of the same polarity. (2) A photoreceptor drum formed by sequentially forming a photoconductive layer and a transparent permanent layer on a conductive substrate, and a photoreceptor drum that is primarily charged to a constant polarity at a predetermined position and simultaneously exposed to light over the entire surface. A first charger and a first lamp are used to secondarily charge the surface of the photoreceptor drum to a polarity opposite to the primary charge at a position in front of the first charger and the first lamp in the rotational direction of the photoreceptor drum. a second charger; a means for obtaining a laser beam modulated such that photoelectricity changes in four stages according to image information of three colors; means for exposing by deflecting and scanning in the width direction;
In front of this polarization scanning position in the rotational direction of the photoreceptor drum are a first developer for developing images of one color and a second color, a second lamp for completely non-lighting, and a second lamp for developing an image of a third color. 1. A multicolor image forming apparatus comprising: a first developing section having a second developing device arranged therein;