JPH04291383A - color image forming 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]

0001

[Field of Industrial Application] The present invention relates to an image forming apparatus using electrophotography, and more particularly to an image forming apparatus that transfers a color image formed on a transparent photoreceptor onto paper at high speed via an intermediate transfer member. Regarding.

0002

2. Description of the Related Art Various types of color image forming apparatuses using electrophotographic technology have been proposed.
No. 288877 and No. 2-212873 are known. In these conventional techniques, as shown in FIG. The three primary color toner images of Y) are once transferred to the intermediate transfer belt 5 for each color, the intermediate transfer belt 5 is rotated three times, a full color toner image is formed on the intermediate transfer belt 5, and then the toner image is further transferred to the recording paper 6. Full-color printing is performed by transferring the image. Since this method uses three rotations, it has the disadvantage that it takes three times as long as monochrome printing.

On the other hand, Japanese Patent Laid-Open No. 153957/1983 is known as a prior art related to miniaturization of image forming apparatuses. As shown in FIG. 3, this conventional technology includes a developing device 12 using a conductive toner 10, a sleeve 11 rotating, and a sheet-like transparent photoreceptor 1.
A DC voltage 14 is applied between 3 and 3, and a laser beam 15 is irradiated from the back side of the transparent photoreceptor 13, so that toner adheres to the surface of the photoreceptor in the area that is irradiated with the light. The attached toner image is printed on recording paper 17 in transfer section 16 . This method does not use a charger, so it is possible to downsize the device, but there are problems such as insufficient contrast potential, which makes it impossible to obtain sufficient image density, and fogging.

0004

SUMMARY OF THE INVENTION As described above, conventional color image forming apparatuses have drawbacks in speeding up and downsizing. Furthermore, image forming apparatuses using transparent photoreceptors have advantages and disadvantages, and image forming apparatuses that support color printing require smaller equipment and higher image quality for color printed matter. An object of the present invention is to solve the problems of the prior art described above, and to enable multicolor or full color printing by electrophotography to be performed at the same speed as monochrome printing, to have sufficient image density, and to be free from fog. An object of the present invention is to provide a compact color image forming apparatus.

[0005]

[Means for Solving the Problems] According to the present invention, a color image is created by firstly transferring a toner image formed on a photoreceptor to an intermediate transfer member, and then secondarily transferring it from the intermediate transfer member to a transferred member. In a transparent color image forming apparatus, a photoreceptor is formed on a transparent substrate, charging is performed from the photoconductive layer side, an exposure system or a photostatic elimination system is placed on the transparent substrate side, and exposure or photostatic elimination is performed from the transparent substrate side. As a result, sufficient image density without fogging can be obtained, and the space factor within the apparatus can also be improved, thus achieving the above objectives.

[0006]

[Function] As mentioned above, the configuration that combines a transparent photoreceptor and an intermediate transfer member enables high-quality, compact color image formation, and is also effective in preventing toner stains in the exposure system and photostatic elimination system. It is.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a color image forming apparatus according to the present invention will be explained in detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a color image forming apparatus according to the present invention, in which a transparent photoreceptor belt 19 is stretched around a roller 20 that rotates in one direction. A method for forming a two-color image using this apparatus will be described in detail. First, the first charger 21
After the surface of the transparent photoreceptor 19 is charged to a certain negative surface potential, it is exposed to light by the first exposure device 22, and then exposed to light by the first developing device 23.
Develop with. As a result, a first toner image is formed on the transparent photoreceptor belt 19. The formed first toner image is transferred to the intermediate transfer body by applying a positive polarity voltage to the first roll-shaped transfer device 27 at the first transfer unit 26 by the intermediate transfer body belt 25 stretched by the movable roller 24. The image is transferred to the belt 25. Subsequently, the cleaning section 28 cleans the toner remaining on the surface of the transparent photoconductor, and the optical static eliminator 29
Static electricity is removed by

Next, the second toner image is transferred to the transparent photoreceptor 19 by the second charger 30, the second exposure section 31, and the second developer 32.
The toner image is transferred onto the intermediate transfer belt 25 at the second transfer section 33. At this time, the second charging, exposure, and developing process is performed in synchronization with the first charging, exposing, and developing process. The toner image thus obtained is transferred to the second transfer section 33.
The image is superimposed on the image on the intermediate transfer belt 25 transferred by the first transfer unit 26 or is transferred at a certain distance. In this example, the color order is the first developing device 2.
3 is color, and the second developing device 32 is black, both of which use a two-component developer and employ a contact development method, but the color order may be from black to color, or the developer may be one component.

The two-color toner image formed on the intermediate transfer belt 25 is transferred onto a recording sheet 34 by a transfer device 35.
It will be established.

In this embodiment, first and second exposure light sources 22, 31 and light eliminating power supplies 29, 36 are arranged inside the transparent photoreceptor belt 19, that is, on the side of the transparent substrate. Figure 4
The structure of the transparent photoreceptor belt 19 is shown in FIG.
A blocking layer 40 of a polyamide resin film as an organic film is formed thereon, and furthermore, an organic photoconductor layer 41 and an insulating protective layer 42 are formed. The intermediate transfer belt 25 in this embodiment has a resistance of 109 (Ωcm).
A conductive plastic sheet of about 100 mL was used. In this embodiment, the first and second exposure light sources 22 and 31 used LEDs, and the first and second optical static elimination light sources 29 and 36 used fluorescent lamps. As shown in FIG. 5, the exposure device 43 has a single LED that serves as a first and second exposure light source, and irradiates the first and second exposure sections through a light splitter 44 and optical fibers 45 and 46. Further, as shown in FIG. 6, the optical static eliminator 47 surrounds one fluorescent lamp with a light-shielding film 48, and surrounds this fluorescent lamp with a highly reflective light-shielding wall 48 to prevent the light from leaking to unnecessary areas. It is also possible to irradiate the first and second optical static elimination parts and serve as the first and second optical static elimination light sources. Furthermore, an LED may be used as the optical static eliminator. In this case, the light is irradiated from the LED to the optical static elimination unit through an optical splitter and an optical fiber.

Embodiment 2 FIG. 7 shows a full-color image forming apparatus according to the present invention. The transparent photoreceptor belt 19 is arranged in one direction (as shown in Example 1 and FIG. 1).
The full-color image forming method using this apparatus will be described in detail below. First, after the transparent photoreceptor belt 19 is charged to a negative surface potential by the first charger 49, it is exposed to light by the first exposer 50, and the formed electrostatic latent image is developed by the first developer 51. conduct. As a result, a first toner image is formed on the transparent photoreceptor belt 19. The formed first toner image is transferred to the intermediate transfer belt 25 stretched by the rotating roller 24 at the first transfer section 52, where a voltage of positive polarity is applied to the first roll-shaped transfer device 53 and transferred to the intermediate transfer belt. 25. Subsequently, the first cleaning section 54 cleans the toner remaining on the transparent photoreceptor belt 19, and the first optical static eliminator 55 removes the static electricity. Hereinafter, in the second transfer section 56, the third transfer section 57, and the fourth transfer section 58, the second, third, and fourth images obtained in the second, third, and fourth charging, exposure, and developing steps, respectively, will be described. transfer the toner image onto an intermediate transfer belt. At this time, the second, third, and fourth charging, exposing, and developing steps are performed in synchronization with the first charging, exposing, and developing steps. The four toner images thus obtained are superimposed on the intermediate transfer belt 25 by the fourth transfer device 59. The multicolor toner image formed on the intermediate transfer belt 25 is transferred onto a recording paper 61 by a fifth transfer device 60 and fixed thereon. In this embodiment, the color order of the developing devices is Y (yellow) for the first developing device, M (magenta) for the second developing device, C (cyan) for the third developing device, and B for the fourth developing device.
For k (black), a contact development method was adopted using a two-component developer, but a single-component developer may also be used.

In this embodiment, first, second, third, and fourth exposure devices 50, 65, 66, 67 and optical static eliminators 55, 6 are used.
8, 69, and 70 were arranged inside the transparent photoreceptor belt, that is, on the transparent substrate side.

In FIG. 8, the exposure device 77 is a single LED, which also serves as the first, second, third, and fourth exposure devices, and the light branching device 78
, optical fibers 79, 80, 81, 82 and a self-hock lens 83 as a focusing light transmission body to irradiate the first, second, third, and fourth exposure areas 84, 85, 86, 87. In this case, the second, third, and fourth exposures are performed in synchronization with the first exposure, and the exposure amount of the LED is adjustable by varying the input voltage, so that the exposure amount is less than the first exposure amount. By setting the second exposure amount<the third exposure amount<the fourth exposure amount, it is possible to deal with insufficient exposure when color toners are overlapped.

In FIG. 9, the optical static eliminator 78 is a single fluorescent lamp, and this fluorescent lamp is surrounded by a highly reflective light shielding wall 79, and the light is transmitted to the first, second, third, and fourth optical static eliminators. 80, 81, 82
, 83. The third optical static eliminator 82 is provided with a shutter 84, and adjusts this shutter to
The amount of light is set to be approximately equal to the amount of light that hits the second and fourth optical static eliminators 80, 81, and 83. The third optical static eliminator 82 is provided with a shutter 84, and this shutter is adjusted so that the amount of light hitting the first, second, and fourth optical static eliminators 80, 81, and 83 becomes approximately equal to the amount of light.

As described above, FIGS. 8 and 9 are useful for reducing the number of LEDs and fluorescent lamps used as exposure devices or optical static eliminators, that is, reducing power consumption.

[0017]

According to the present invention, one intermediate transfer belt can be conveyed along one or more concave portions, and a plurality of toner images can be sequentially superimposed by one passage.
Color images can be obtained at the same printing speed as monochrome printing, and
Since the exposure system and optical static elimination system are placed inside the transparent photoreceptor, that is, on the substrate side, it is possible to prevent toner stains on the exposure system and optical static elimination system that tend to occur in color image forming devices, and it is also possible to reduce the size of the device. can be converted into

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a two-color image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram showing a color image forming apparatus using a conventional intermediate transfer member.

FIG. 3 is a diagram showing an image recording device using a conventional transparent photoreceptor.

FIG. 4 is a diagram illustrating the configuration of main parts of a transparent photoreceptor.

FIG. 5 is a diagram showing another embodiment of the two-color image forming apparatus according to the present invention.

FIG. 6 is a diagram showing another embodiment of the two-color image forming apparatus according to the present invention.

FIG. 7 is a schematic configuration diagram of a full-color image forming apparatus showing an embodiment of the present invention.

FIG. 8 is a diagram showing another embodiment of a full-color image forming apparatus according to the present invention.

FIG. 9 is a diagram showing another embodiment of a full-color image forming apparatus according to the present invention.

[Explanation of symbols]

1... Photoreceptor belt, 2... Charger, 3, 43, 77... Exposure device, 4, 12... Developing device, 5, 25... Intermediate transfer belt, 7
, 29, 36, 47, 78... Optical static eliminator, 8, 37... Cleaner, 9... Transfer device, 10... Conductive toner, 11... Sleeve, 13... Transparent photoreceptor, 14... DC voltage, 15... Laser light, 16 ...Transfer section, 6, 17, 34, 61...Recording paper,
18... Mag roll, 19... Transparent photoreceptor belt, 20... Roller (for photoreceptor belt), 21, 49... First charger, 2
2,50...first exposure device, 23,51...first developing device, 24
...Roller, 26, 52...First transfer section, 27...Roll-like transfer device, 28...Cleaning section, 30, 74...Second charger, 31,65...Second exposure device, 32,62...Second developer Part, 33... Second transfer part, 35... Transfer device, 38... Polyester transparent substrate, 39... Transparent conductive film, 40... Blocking layer, 41... Photoconductor layer, 42... Insulating protective layer, 44... Optical splitter, 45, 46... Optical fiber, 48, 79... Light shielding wall,
53...First roll-shaped transfer device, 54...First cleaning section, 55...First photostatic eliminator, 56...Second transfer section, 57...Third transfer section, 58...Fourth transfer section, 59...Fourth transfer Vessel, 60...
Fifth transfer device, 63...Third developer, 64...Fourth developer, 6
6...Third exposure device, 67...Fourth exposure device, 68...Second optical static eliminator, 69...Third optical static eliminator, 70...Fourth optical static eliminator, 71...
Second cleaning section, 72...Third cleaning section, 73
...Fourth cleaning section, 75...Third charger, 76...Fourth charger.

Claims (7)

[Claims] 1. Toner images formed by each developing device on a transparent photoreceptor are once transferred onto an intermediate transfer member, a plurality of toner images are superimposed on the intermediate transfer member, and the toner images are further transferred onto recording paper. A color image forming apparatus characterized by: 2. A color image according to claim 1, wherein a single light source is disposed on the transparent substrate side of the transparent photoreceptor, and light is irradiated from each reflective member of a plurality of optical static eliminators from the single light source. Forming device. 3. The color image forming apparatus according to claim 2, wherein the light source is a fluorescent lamp, and the plurality of optical static elimination units are irradiated with light. 4. The color image forming apparatus according to claim 2, wherein the light source is an LED, and the light is branched from the LED and irradiated to each optical static elimination section through an optical fiber. 5. The color image forming apparatus according to claim 1, wherein an exposure source is disposed on the transparent substrate side of the transparent photoreceptor, the light is branched through an optical fiber, and an image is formed on each exposed portion by a convergent light transmission member. . 6. The color image forming apparatus according to claim 1, wherein the transparent photoreceptor is belt-shaped and has an organic photoconductive layer and a blocking layer. 7. The color image forming apparatus according to claim 6, wherein the exposure source is an LED.