JPS636579A - Color image forming device - Google Patents

Abstract

PURPOSE:To obtain a color image which is excellent in its color reproducibility, by providing a shutter member on a position which is opposed to the photosensitive drum of an exposure system. CONSTITUTION:By driving a rotary solenoid 63, the opening/closing part 64 of a casing 61 is opened and closed. The shutter member is provided on one end of the casing 61. The shutter member consists of a side arm 62a fixed and provided on the movable part of the rotary solenoid 63, and a shutter plate 62b for covering the opening part 64, and when a power source of the rotary solenoid 63 is off, light shielding and dust preventing actions are executed by covering an aperture 64 with the shutter plate 62b, and when the power source of the rotary solenoid 63 is turned on, an exposure is executed by moving the shutter plate 62b from the aperture 64. Accordingly, while the shutter is closed up, contamination caused by a fact that a toner is stuck to a light source part is scarcely generated, therefore, the drop of the light quantity of each light source is prevented, and the reduction of the gradation reproducibility and the color reproducibility is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus, and in particular to a color image forming apparatus that is equipped with a photoreceptor having a color separation function, a light source and a developing device on the periphery of the photoreceptor drum. This is an inspiration for image forming devices.

[Background of the invention]

The applicant is @sa, Japanese Patent Application No. 59-83096, No. 59
-187044 No. 60-229524 etc.
A photoreceptor that has a color separation filter, an insulating layer on its surface, and a color separation function within its surface is charged and imagewise exposed, and then the entire surface is exposed to specific light and development is repeated to obtain a color image. We are proposing a method for forming color images.

FIG. 4 shows an example of the layer structure of the photoreceptor used in the above color image forming method, where 1 is aluminum;
It is a conductive cylindrical or belt-shaped substrate made of nickel or the like, 2 is a photoconductive layer or a functionally separated photoconductive layer consisting of a charge generation layer and a charge transfer layer, and 3 is a base made of various polymers, resins, etc. Red (R) formed by dye or pigment colorants
), green (CG), blue (B), and other color separation filters. FIG. 5 shows the absolute layer 3, and the filter layer provided on the insulating layer may have a striped distribution as shown in FIG. 5(a), or a filter layer as shown in FIG. 5(1). A mosaic distribution is used.

However, the arrangement pattern of the filter layer is not limited to this, and the number of color separation filters per unit area does not necessarily have to be the same, but the number of green (G) color separation filters can be adjusted according to human visibility. You can increase it to 6. Here in the diagram! The length l of each filter part shown by is 10 to 500μ as a condition for good image resolution and color reproducibility.
A range of 1 is used. Red (R), green (G), and blue (B) color separation filters are filters for color separation that transmit only red light, green light, and blue light, respectively, and the transmittance for each filter light wavelength is, for example, It is as shown in Figure 6.

Photoconductivity/! 12 includes, for example, 5eTe and A as selenium-based materials.
s2Se:+ etc. are used, and the spectral sensitivity in that case is as shown in FIG. 5eTe is sensitized by doping with Te to obtain red sensitivity.

The applicant has proposed that the process of imagewise exposing the photoreceptor to light as described above, and then performing development through full-scale exposure with light that passes only through a specific color separation filter section, can be applied to different types of color separation filter sections. We have proposed a color image forming method in which a color image is obtained by repeating several steps. At this time, color toner of a color complementary to the color light transmitted through each filter as shown in Figure 8 is used for development, and a multicolor image is formed on the photoreceptor by one transfer. A multicolor image is recorded on a transfer material all at once.

Here, the process of forming a color image using the above-mentioned photoreceptor will be explained with reference to FIG. The figure shows a part of a photoreceptor that uses an n-type (that is, high electron mobility) photosemiconductor such as cadmium sulfide as a photoconductive layer, and depicts the image formation process there in a chivalrous manner. , and in Figure 6, in which cross-sectional hatching of each part is omitted, 1 and 2 are a conductive substrate and a photoconductive layer, respectively, and 3 is an insulating layer including three color separation filter parts R and G1B. Further, the graph at the bottom of each figure shows the potential on the surface of each part of the photoreceptor.

First, as shown in FIG. 10 [1], when a positive corona discharge is applied to the entire surface by the charger 4, a positive charge is generated on the surface of the insulating layer 3, and correspondingly, a positive charge is generated on the surface of the insulating layer 3. A negative charge is induced at the interface.

Next, as shown in FIG. 10 [2], alternating current or negative discharge is applied by the charger 5 equipped with an exposure slit to erase the charge on the surface of the insulating layer 3 while exposing a colored image, for example, red image exposure LR. give.

The red light passes through the red filter section R of the insulating Ni 3, and in order to make the photoconductive layer 2 under it conductive, the charges in the photoconductive layer 2 are erased in the same filter section. On the other hand, since the green filter section 3G and the blue filter g3B do not transmit red light, the negative charges on the photoconductive layer 2 remain as they are. Further, due to the action of the charger 5, the charge distribution on the insulating layer 3 changes so that the surface potential of the photoreceptor becomes uniform.

The primary latent image is formed in the manner described above. The portions of the document irradiated with the green and blue components also give similar results for each filter section. The primary latent image is a state in which all color components exist as an image-like charge distribution under each filter section. At this stage, not only the portions on the photoconductive layer 2 where the charges have been erased, but also the portions where the charges remain have the same potential on the surface of the photoreceptor, and therefore do not function as an electrostatic image.

Although FIG. 10 [2] shows a case where the potential after charging is approximately zero, it may be charged to a negative level.

Next, as shown in FIG. 10 [3], the entire surface is exposed to light transmitted through one of the filters included in the insulating layer 3, for example, light [6B] and blue light L8 obtained by the blue filter F-. Then, the photoconductive layer 2 below the filter 28 that transmits blue light becomes conductive, and a part of the negative charges of the photoconductive KL layer 2 and the charges of the conductive substrate 1 in this area are neutralized, and the filter B
Only the surface charge remains, which creates a potential pattern. No change occurs in the G and R portions that do not transmit blue light; this is the second latent image. And filter B
When the above charge image is developed with a developer containing negatively charged yellow toner T3T, the toner adheres only to the surface of the filter 8 portion where the potential is relatively high, and development is performed (first
Figure 0 (4)).

Next, in order to eliminate the potential difference that has occurred, the surface potential is made uniform by charging 814 with a polarity opposite to that of the charger 4 as shown in FIG. 10 [5], and then the entire surface is exposed with green L1f as shown in FIG. 10 [6]. When given, a second latent image is formed in the green filter section G, as in the case of blue light. This is number 10
If development is performed with magenta toner Tm as shown in FIG. 7, magenta toner T will adhere only to the filter G portion.

Subsequently, as shown in FIG. tjS10 [8], after making the surface potential uniform in the same way, the entire surface is exposed to red light, and the second latent image appearing on the red filter portion R is developed with cyan toner Te.

In the illustrated example, since there is no charge in the photoconductive layer 2 of the red filter R, no potential difference is generated even when the entire surface is exposed, and no cyan toner is attached even when development is performed with cyan toner.

When the toner image thus obtained is transferred onto a transfer material such as copy paper and fixed, a red image is reproduced on the transfer material due to the color mixture of yellow toner Ty and magenta toner T.

As the image exposure light source and the entire surface exposure light source for the image forming process described above, the blue, green, and red 3M! It is suitable to use M fluorescent lamps or cold cathode discharge lamps because they provide good efficiency and allow easy adjustment of color balance.

[Problem that the invention seeks to solve]

In the color image forming apparatus using the method described above,
Similar to color image forming devices using normal electrophotography,
When developing a latent image, toner floats around the developing device in the form of a mist, and this toner mist adheres to the surface of an object in the vicinity of the developing device, causing a problem in that it contaminates the object. Therefore, in a typical electrophotographic copying apparatus, the portion of the optical system facing the photoreceptor must be periodically cleaned after a predetermined period of time has elapsed.

As a method for preventing staining of the optical system due to the above-mentioned toner, when using magnetic toner, there is a method described in Japanese Patent Application Laid-Open No. 53-563.
A method of providing a magnet around the optical M opening described in Publication No. 1,
- In general cases, the method of attaching a dustproof duct to the optical system described in JP-A-56-87063, JP-A-58-1
A method of attaching a removable transparent body to an optical system as described in Japanese Patent No. 94022 has been proposed.

However, the method of installing a magnet and the method of installing a dustproof duct as proposed above have a small effect on preventing dirt, and the method of installing a dustproof duct and the method of installing a transparent body have the problem of increasing the volume of the device. Ta.

Color image type equipped with a photoreceptor with color separation function! In the & device, a plurality of developing devices are provided around the photoconductor periphery, and the J1 effect is large (in particular, if the toner adheres to the image exposure light source and the entire surface exposure light source, the light intensity of the light source decreases). In addition to insufficient image exposure, the light sources for each color are not aligned, resulting in loss of color balance and deterioration of gradation reproducibility and color reproducibility.

The present invention has been made to solve these problems, and is equipped with a device that prevents the image exposure light source and the entire surface exposure light source from being contaminated by the toner. An object of the present invention is to provide a color image forming apparatus that can obtain color images with excellent quality.

[Means for solving problems]

The above purpose is color separation 8! This is achieved by a color image forming apparatus having a photoreceptor with a photoreceptor having a photoreceptor drum, which is characterized in that a shutter member which can be opened and closed is provided in a portion of the exposure system facing the photoreceptor drum.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

Figures 1 to 43 show an embodiment of the present invention,
Figure PIIJ1 is a diagram showing the internal configuration of the color image forming apparatus of the present invention, Figure 12 is a diagram showing the configuration of the entire surface exposure unit of the above embodiment, (a) is a sectional view of the photoreceptor in the drum pongee direction, (b) ) is a sectional view taken along line X-X of (a), (c) is a side view,
Figure tjS3 is a diagram showing the configuration of the image exposure unit 7)A.
) is its perspective view, and (b) is its cross-sectional view.

First, in order to make it easier to understand, the entire surface exposure unit 6, which is the light source for full surface exposure shown in FIG. 2, will be explained.

In the figure, 61 is a casing in which a fluorescent lamp 24 is suspended and a filter F is provided in the opening 64, and the interior thereof includes a reflecting mirror 61a having an arcuate cross section and an id portion 61b having a straight M portion. It consists of Fluorescent lamp 24 and filter F
There are three types of light: blue (B), green (G), and red (R), and fluorescent lamps 24 of the same color and filter F are combined to produce sharp blue, green, and red light with a sharp spectrum as full-surface exposure light. It is designed to irradiate the surface of the photoreceptor.

At one end of the casing 61 is a rotary lenoid 63.
A shutter member 62 driven by the rotary lens 63 is provided to open and close the opening 64 of the casing 61. The shaft member 62 is made up of a side arm 62a fixed to the movable part of the rotary lenoid 63 and a shatter plate 62b, which is a strip-shaped member having an arcuate cross section and can cover the opening 64. When the power is OFF, the shutter plate 62b covers the opening 64 of the entire exposure unit to perform light shielding and dustproofing, and when the power of the rotary lens 63 is turned ON, the shutter plate 62b moves from the opening 64 to perform exposure. It has become.

The image exposure unit (A20) for the image exposure light source shown in FIG. 3 also shows an embodiment in which a rotary lens is used to open and close the image exposure unit. 3(a) is a perspective view of the image exposure unit A20, and FIG. 3(b) is a cross-sectional view. A red fluorescent lamp 24R and a green fluorescent lamp 24G are suspended inside the reflecting mirror 21, which has a cross section that approximates an ellipse.6 A slit-shaped opening 22 is formed in a part of the reflecting mirror 21.
is provided, and the red light and green light are mixed and emitted from the opening 22.

There is a rotary lenoid 163 at the side end of the reflection 1121, and a movable part of the rotary lenoid 163 includes a side arm B2.
A shirt cover plate 62b is provided which is supported by the opening 22 and has an arcuate cross section and a rectangular shape so as to cover the opening 22. The shutter plate 132b blocks the opening 22 of the rotary lenoid 163's power supply (for image exposure light source when it is OFF) A20, and functions as light shielding and dust prevention.When the rotary lenoid 163 is powered on, the shutter plate 62b It moves from the opening 22 and performs exposure.

FIG. 1 shows an image exposure unit 20 equipped with the above-mentioned shutter and an image exposure unit 23 equipped with a shutter and incorporating a blue fluorescent lamp 24B and a red fluorescent lamp 24R arranged symmetrically thereto.
blue, green, and red full-surface exposure units equipped with the shutters described above) 6 B, 6
The color image forming apparatus of the present invention is configured to perform full-surface exposure using G and 6 R, and the operating order will be explained. In the figure, reference numeral 41 denotes a photosensitive drum having the configuration shown in FIG. 4, which rotates in the direction of arrow a during a copying operation. The photoreceptor drum 41 is rotated and irradiated with light as necessary, and the entire surface is charged with an electric charge by the electric current device 4, and an alternating current or electric current is applied from the next electrode 5 equipped with an exposure slit.
Image exposure unit while receiving corona discharge of opposite polarity) 2
The image exposure light of the irradiated original is given by 0.23, and the first latent image forming process is completed. Next, the entire surface is exposed to blue light La obtained by the combination of the entire surface exposure unit (second light source 22) 6B and the light source blue filter FII, and a second latent image of yellow component is formed.
Next, this is developed by a developing device 17Y loaded with yellow toner. Next, a recharger 1 with a polarity opposite to that of the primary charger 4
After the surface of the photoreceptor is brought to a uniform potential by step 4, the entire surface exposure unit (second light source 22) 6G, green light source filter F
The entire surface is exposed to green light Lm from 4, and the magenta toner is subjected to development by a developing device 17, which carries the magenta toner in the vc term. Furthermore-
The potential of the photoreceptor is made uniform by the recharging device 15, which has a polarity opposite to that of the electric charger 4, and the entire surface is exposed by the red light L^ from the red light 'fl filter F11. Developer device 1 loaded with cyan toner
Developed using FuC. As a result, the photoreceptor drum 41
A color image consisting of yellow, magenta, and cyan toners is formed thereon. The obtained color toner image is banded by a pre-transfer charging electrode 8 and then transferred by a transfer electrode 9 onto a transfer material P supplied by a paper supply means. The transfer material carrying the color toner image to be transferred is separated from the photoreceptor drum 41 by the separation electrode 10,
A completed color copy is fixed by the fixing device 11, and is discharged outside the machine. After the transfer, the photosensitive drum 41 is irradiated with neutralizing light to eliminate static electricity, and the cleaning blade 12 in the cleaning V device 13 removes the toner remaining on the surface, and the drum 41 is used again.

In this example, a color separation filter with a thickness of 25 μl was prepared by printing a filter pattern as shown in FIG. 5 on a polyethylene terephthalate thin film with a thickness of 20 μl.
It was deposited on an A srs e3 photoreceptor, which is sensitive to the long wavelength side, as shown in FIG. The As2Se3 photoconductor is a P-type (large hole movement) photoconductor similar to the 5eTe photoconductor, and N; is used for the base material in order to inject charge during electric power. The toner also has yellow (Y) as shown in Figure 8.
, magenta (M), and cyan (C) with an average particle diameter of 4 μs.

In this example, a fluorescent lamp having an emission spectrum shown in FIG. 9 was used as a light source for image exposure and a light source for whole surface exposure.

Regarding the installation position of the contamination prevention shutter, for the image exposure light source, there are two locations other than the installation position shown in Figure 3.
It is also possible to provide it between the exposure slit attached to the secondary charger 5 and the fourth mirror. In this embodiment, the shutter of the full-surface exposure unit 6 is provided in front of the full-face exposure filter F, as shown in Figure tjS2, and the distance between the shutter plate and the surface of the photoreceptor is approximately 11 degrees, so that it can be used not only for fluorescent lamps but also for filters. It was designed to prevent contamination from part F.

The shutters of both the image exposure light source and the entire surface exposure light source are closed except during irradiation. Therefore, the lighting and extinguishing of the light source part can be set more freely than in the past, and it has become possible to keep the light on throughout the process as shown in FIG. 11. By providing a pre-lighting time in this way, the light amount is stabilized for both image exposure and full-surface exposure, and images with good color reproducibility can be obtained. In this example, the sequence in which the image exposure light source is turned off while the optical system is restored is used. The shutter is opened and closed immediately after scanning the document. If the entire surface exposure light source is turned on and irradiated only when the image forming area passes through the entire surface exposure light source part, there is a possibility that the light irradiation will be performed before the light amount is stabilized. The exposure light source was kept on, and the image forming area was irradiated with light using a shutter.

In this embodiment described above, the shutter release time of the image exposure light source and each full-surface exposure light source is about 1 time per step of forming one image.
Since there is almost no contamination by toner while the shutter is closed, the contamination of the optical system according to the present invention is about 18 compared to the conventional method. It became a degree.

〔Effect of the invention〕

In the color image forming apparatus of the present invention, toner adhesion to the light source portion is significantly reduced, thereby preventing a reduction in the light intensity of each light source due to toner adhesion, and preventing deterioration of gradation reproducibility and color reproducibility. A preventive effect occurred. In addition, according to the present invention, the degree of cleaning of the optical system that is required is reduced,
This also had the effect of reducing maintenance costs.

[Brief explanation of the drawing]

Figures 1 to #S3 show one embodiment of the present invention.
1 is a diagram showing the internal deterioration of the color image forming apparatus of the present invention, FIG. 2 is a diagram showing the configuration of the entire surface exposure unit, FIG. 3 is a diagram showing the configuration of the image exposure unit, and FIG. 4 is a diagram showing the configuration of the photoreceptor. /I
A diagram showing the configuration, tjSS diagram is a plan view of the insulating layer, fjS6
The figure is a graph showing the spectral transmittance of color M filters. 57
Figure 8 is a graph showing the spectral sensitivity of the photoreceptor, Figure 8 is a graph showing the spectral reflectance of color toner, Figure 9 is a graph showing the spectral reflection efficiency of fluorescent lamps, and fjS10 is a graph showing the image forming process. -Illustration. Figure fjS11 is a diagram showing a sequence in image formation. In the figure, 1... Conductive substrate 2... Photoconductive layer 3... Insulating layer 4... - Personal electrical device 5.14.15...
・Secondary charger 6.6B, 6G, 6R...Full surface exposure unit 7...
Image exposure mounting 11...Fixing device 17Y, 17M,
17C...Developer 20, 23...Image exposure unit 24.24B, 24G, 24R...Fluorescent lamp 63.16
3...a-talinlenoid 21.61a...reflector 22.64...opening 62a...side arm
62b...Shutter plate F...Filter applicant: Roku Konishi Photo Industry Co., Ltd. Figure 1 Figure 3 (α) Figure 12. b, (0 Fig. 4 R-1 color 13 minute step! Fig. 5 (a,) Fig. 5 Cb Fig. 6 Fig. 6 400 450 500 550 6
C0650700 Wavelength (nm) 400 Father 0 600 700
800 short length (yytyyt) Figure 8 Growth λ (nm) Color toner

[1] [4] Figure 10 [2] Convex

[3] 11th

[5] [8] Figure 9 [6) ,7''

Claims (2)

[Claims] (1) A color image forming apparatus having a photoreceptor having a color separation function, characterized in that a shutter member that can be opened and closed is provided in a portion facing a photoreceptor drum of an exposure system. (2) The color image forming apparatus according to claim 1, wherein the exposure system is an exposure system using an image exposure light source and an entire surface exposure light source.