JP2876902B2 - Color electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color electrophotographic apparatus applicable to a color copying machine, a color printer and the like.

[0002]

2. Description of the Related Art In a general electrophotographic method, in order to form a color image, a method of superposing a yellow, magenta, cyan or even a black toner image on a transfer material is employed. As a method of performing the superposition of the toner images on the transfer material, a transfer drum method of repeatedly transferring the transfer material wound around the transfer drum to the same transfer position and superimposing and transferring each color toner image sequentially formed, and a plurality of transfer drum methods. In general, a continuous transfer method in which image forming units are arranged side by side and toner images of respective colors are successively superimposed and transferred onto a transfer material at separate transfer positions.

As an example of a color electrophotographic apparatus using the latter continuous transfer method, there is JP-A-2-16580. FIG. 7 shows a printer unit which is an image forming unit of a copying machine disclosed in Japanese Patent Laid-Open No. 16580/1990. In this example, four image forming units, each having a photoreceptor, an exposure device, etc., are arranged for forming images of four colors, and the paper conveyed to the belt passes through the transfer section of each photoreceptor and a toner image is formed. Superimposed. The digital signal sent from the image reading unit is input to the printer unit and sent to the laser exposure device for each color signal, black 1Bk, cyan 1C, magenta 1M, and yellow 1Y. Four sets of image forming units 2Bk, 2C, 2M, and 2Y are juxtaposed in the printer unit. Since each image forming unit 2 is made of the same constituent member,
And the units for other colors are omitted. Note that the same reference numerals are assigned to the same parts for each color, and a suffix indicating each color is added to the code to distinguish the configuration of each color. The image forming unit 2C has a photosensitive drum 3C in addition to the exposure device 1C. The photoconductor 3C has a charger 4C, an exposure device 1C, a developing device 5C, a transfer charger 6
C and the like are arranged similarly to a known electrophotographic apparatus. The photoreceptor 3C uniformly charged by the charger 4C forms a latent image of a cyan image by exposure by the exposure device 1C, and develops by a developing device 5C to form a visible toner image. The transfer paper (not shown) is conveyed by a transfer belt 7 and has photoconductors 3Bk, 3C, 3C,
M, 3Y, and the toner image is transferred by the operation of the transfer device 6. Thus, a full-color image is obtained on the transfer paper.

Further, in US Pat. No. 4,905,048,
As another method of forming a color image by superimposing toner images of different colors on a transfer material, a method is disclosed in which a transfer material is reciprocated with respect to a photoreceptor, transfer is repeated, and a toner image is superimposed.

[0005]

Problems to be Solved by the Invention
In the continuous transfer method disclosed in Japanese Patent No. 16580, an image forming position equal to the number of colors is required, and therefore, an exposure unit for exposing an image on a photoreceptor is required for the number of colors, and the apparatus becomes expensive. Further, in this configuration, as exemplified in JP-A-1-250970, high accuracy is required for each color alignment of the exposure apparatus, and a special device and a complicated configuration are required for the image exposure system. There is also a problem. Furthermore, since the image forming positions are separately provided at a plurality of positions, it is difficult to align the respective colors on the transfer material, and in addition to the above-described difficulty of the aligning of the exposure apparatus, the color shift is likely to be large. There is also a problem.

Further, in the example disclosed in US Pat. No. 4,905,048 in which a transfer material is reciprocated to form a color image, toner images of respective colors are formed in order using the same photosensitive member. 2) The structure and control for moving the transfer material away from and to the photoconductor when the transfer material is reversed are complicated, and 3) The structure and control for separating and moving each color developing device from the photoconductor are complicated. .

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to eliminate the need for a complicated structure for aligning an image exposure system, to accurately align each color, and to increase the capacity of a developer reservoir of each image forming unit. However, an object of the present invention is to provide an excellent color electrophotographic apparatus having a small and simple configuration as a whole, and having a simple configuration of an image forming unit including a photoreceptor and a developing device and easy replacement.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a rotating photosensitive member and developing means having toners of different colors, each having a different color. Transfer means for carrying a plurality of movable image forming means for forming a toner image, and transfer means for carrying a transfer material and reciprocating and transferring the toner image on the photoconductor to the transfer material at the same transfer position And an exposing means for exposing an image at the same exposure position corresponding to the transfer position, and a plurality of image forming means arranged adjacently in a horizontal direction, the image forming position corresponding to the transfer position and corresponding to the exposure position And a moving unit for sequentially moving each of the plurality of image forming units to form a color image by superimposing toner images of different colors on a transfer material, and fixing the color image on the transfer material by a heat fixing unit. A photographic device A color electrophotographic apparatus, characterized in that the arrangement order of the plurality of image forming means for placing the image forming means black most position fixing-side in the horizontal direction.

The present invention also provides a rotating photosensitive member, a charger for charging the photosensitive member, toner of different colors, a developer reservoir for storing the toner, and a developing device for developing the photosensitive member with the toner. And a plurality of image forming means for forming toner images of different colors on the photoreceptor, and a reciprocating and carrying transfer material, and the photoreceptor at the same transfer position. A transfer / conveying unit having a transfer unit for transferring the upper toner image onto a transfer material; an exposure unit for exposing an image at the same exposure position corresponding to the transfer position; and a plurality of image forming units adjacently arranged in a horizontal direction Moving means for sequentially moving each of the plurality of image forming means to an image forming position corresponding to the transfer position and the exposure position, and superimposing and transferring toner images of different colors on the transfer material. Perform color image formation, A color electrophotographic apparatus for obtaining a color image on a copying material, wherein a part of a developer reservoir of an image forming unit uses a space above a charger of an adjacent image forming unit. It is a color electrophotographic apparatus.

Further, the present invention provides a rotating photosensitive member, a charger for charging the photosensitive member, toner of different colors,
A plurality of image forming means, comprising: a developer reservoir for storing toner; a developing device for developing a photoconductor with the toner; and a cleaner for cleaning the photoconductor, and forming toner images of different colors on the photoconductor. And a transfer means for carrying a transfer material and reciprocating and transferring the toner image on the photoreceptor to the transfer material at the same transfer position, and an image at the same exposure position corresponding to the transfer position. Exposure means for exposing;
A transfer means for sequentially moving each of the plurality of image forming means to an image forming position corresponding to a transfer position and an exposure position, wherein the plurality of image forming means are adjacently arranged in a horizontal direction; A color electrophotographic apparatus for forming a color image by superimposing and transferring a toner image of a different color on a material to obtain a color image on a transfer material, wherein a part of a developer reservoir of an image forming means is adjacent to an adjacent image. A color electrophotographic apparatus, characterized in that the apparatus uses a space above a cleaner as a forming means.

Furthermore, the present invention comprises a plurality of movable photosensitive members each having a rotating photosensitive member and developing means having toner of a different color, and forming toner images of different colors on the photosensitive member. An image forming unit, a transfer conveying unit including a transfer unit for carrying a transfer material and reciprocating and transferring a toner image on a photoreceptor to the transfer material at the same transfer position, and the same exposure corresponding to the transfer position Exposure means for exposing an image at a position and a plurality of image forming means are horizontally arranged side by side, and each of the plurality of image forming means is sequentially moved to an image forming position corresponding to a transfer position and an exposure position. A color electrophotographic apparatus having a transfer unit, and superimposing and transferring toner images of different colors on a transfer material to form a color image, and obtaining a color image on the transfer material. Each alone A color electrophotographic apparatus which is a shape that can be extracted in order upward.

[0012]

According to the present invention, a color image is formed on transfer paper electrostatically attracted to a transfer belt having a relatively simple structure without using a transfer section having a complicated structure as in a conventional transfer drum. By performing the formation, the reliability of paper conveyance can be improved with a simple apparatus configuration.

Further, as compared with a continuous transfer apparatus having four image forming positions, all the color images are formed at the same position, so that the configuration of the exposure apparatus and the like can be simplified, and the alignment of the color images can be performed accurately.

Further, when the developing device and the photosensitive member are separated from each other, the problem of scattering of the toner and the developing material is likely to occur. However, in the present invention, the image forming means constitutes an independent image forming unit for each color. There is an advantage that troubles such as toner spillage are less likely to occur when moving each color unit to the image forming position.

Further, even in a color electrophotographic apparatus, the use of black alone is the most frequent use in printing a document or the like. At this time, as shown in FIG. When the black unit is placed, the other color units are left at a position away from the fixing device, which is the heat source, so even if many sheets are printed for a long time, the other color units are affected by heat and the trouble such as toner coagulation occurs. Can be avoided.

Further, since black is most frequently used alone in general use, if the black image forming unit is arranged at the image forming position during the image forming operation standby time, as described above, the other color unit is used. Not only can be protected from trouble caused by heat, but also the time until the start of the printing operation can be shortened. Thus, when the color electrophotographic apparatus of the present invention is used alone in black, performance comparable to that of a general black-and-white electrophotographic apparatus can be obtained.

Usually, the space above the charger is not used at all and becomes a useless space. However, if it is used as a space for storing the developer of an adjacent image forming unit, when four units are arranged side by side. The space can be used as efficiently as possible without changing the size of the entire unit group. At this time,
When each of the image forming units has a side shape that can be pulled out obliquely upward, for example, a parallelogram shape, only one image forming unit can be pulled out alone from a group of four image forming units. This produces a very excellent effect on maintenance when replacing the image forming means for each color.

[0018]

The photosensitive member used in the present invention can be zinc oxide, selenium, cadmium sulfide, amorphous silicon, or an organic photosensitive member using phthalocyanine or azo pigment.

In the present invention, a two-component developer comprising a toner and a magnetic carrier can be used. The toner used in the present invention is obtained by dispersing a color pigment such as carbon black or phthalocyanine in a binder resin such as an acrylic resin or a polyester resin, pulverizing and classifying the resultant. The toner may be a powder obtained by spray drying or a powder chemically synthesized by a pearl polymerization method, an emulsion polymerization method, or the like. Further, the toner particles may be directly mixed with the carrier, or may be mixed after silica fine particles or fluororesin fine powder is adhered to the surface of the toner. The average particle size of the toner used is desirably 15 μm or less, but if it is 12 μm or less, a sharper image can be obtained. The carrier used in the present invention may be a magnetic material such as iron powder or ferrite powder, or a powder whose surface is coated with a resin, or a fine powder such as ferrite powder or magnetite.
Magnetic powder or the like, which is dispersed and mixed in a styrene resin, an epoxy resin, a styrene acrylic resin, or the like at a ratio of about 0 to 80% and pulverized and classified, is used. The average particle size of the carrier is 300
μm or less is preferable, but if it is 150 μm or less, the toner can be uniformly charged.

Since the image forming units used in the present invention are made of the same components except for the developer contained therein, the image forming unit for magenta will be described and the other colors will be omitted to simplify the description. . Note that, for each color, the same portions are denoted by the same reference numerals, and when it is necessary to distinguish the configuration of each color, a character indicating each color is denoted by the reference numeral. 2 to 5, the magenta image forming unit 8M is shown in detail. In each of the drawings, the position of an adjacent image forming unit is indicated by a broken line.

In FIG. 2, reference numeral 9 denotes a drum-shaped organic photoreceptor as a photoreceptor in which phthalocyanine is dispersed in a polycarbonate binder resin, 10 denotes a magnet fixed coaxially with the axis of the photoreceptor 9, and 11 denotes a photoreceptor. A corona charger for negatively charging, 12 a grid electrode for controlling the charging potential of the photoconductor, 13 a laser beam scanning light, and 14 a developer reservoir. In the developer reservoir 14, a two-component developer 17M obtained by mixing a toner 16M and an iron powder carrier 15M having a particle diameter of 100 μm coated on the surface with a silicone resin was placed, and was attached to the surface of the photoreceptor 9 by the magnetic force of the magnet 10. . The toner used is obtained by dispersing a pigment in a polyester resin and further adding an additive. Reference numeral 18 denotes a toner regulating blade made of a magnetic stainless steel, 19 denotes a developer collecting electrode roller made of aluminum, 20 denotes an AC high voltage power supply for applying a voltage to the developer collecting electrode roller, and 21 denotes a toner scraping toner on the developer collecting electrode roller. It is a scraper made of polyester film. Reference numeral 22 denotes a cleaner for cleaning the toner remaining on the surface of the photoconductor after transfer. The magnetic flux density on the surface of the photoconductor 9 is 800 gauss at the maximum position. The diameter of the photoconductor 9 is 30 mm
At a peripheral speed of 120 mm / s. This unit has an advantage that when four units are arranged, each unit can be pulled out in the direction of arrow A, but the upper space B of the charger 11 and the cleaner 22 shown by a two-dot chain line cannot be effectively used. There are drawbacks.

Another improved image forming unit which can also be used for image formation is shown in FIG. In FIG. 3, 2
Reference numeral 3 denotes a developer reservoir having a configuration in which space is effectively used in consideration of the shapes of adjacent image forming units. In this image forming unit, the capacity of the developer reservoir can be made about 1.5 times larger than the unit shown in FIG. However, when replacing the single image forming unit 8M, the arrow C in FIG.
In the direction of arrow D and in the direction of arrow D, they cannot be removed because they hit adjacent image forming units. For example, when the image forming unit arranged on the rightmost side of the four image forming units is pulled out upward, there is a drawback that all the adjacent left side units must be drawn out before being taken out. Therefore, in this case, there is a restriction in the design of the apparatus that the image forming unit must be drawn in the front direction in the drawing.

FIG. 4 shows an image forming unit in which the problems of the image forming unit shown in FIG. 3 are improved. In FIG.
Numeral 24 is for effectively utilizing the upper space of the charger and the cleaner section of the adjacent image forming unit as a developer reservoir, and taking into consideration the ease of taking out the image forming unit alone. In this image forming unit, the capacity of the developer reservoir can be increased, and even when four units are arranged, the image forming unit can be taken out alone in the direction of arrow E in FIG. The configuration of this image forming unit will be described. Inside the developer reservoir 24, an iron powder carrier 15 having a particle size of 100 μm and having a surface coated with a silicone resin.
A two-component developer 17M in which M and toner 16M are mixed is added, and is attached to the surface of the photoreceptor 9 by the magnetic force of the fixed magnet 10. The toner used is obtained by dispersing a pigment in a polyester resin and further adding an additive. Reference numeral 25 denotes an aluminum developer recovery electrode roller, and reference numeral 26 denotes a magnet fixed inside the developer recovery roller. Reference numeral 20 denotes an AC high-voltage power supply for applying a voltage to the developer collection electrode roller, and reference numeral 21 denotes a polyester film scraper that scrapes off the toner on the developer collection electrode roller. Reference numeral 22 denotes a cleaner for cleaning the toner remaining on the surface of the photoconductor after transfer.

FIG. 5 shows still another image forming unit.
This uses a magnetic brush developing method which is common in a conventional electrophotographic apparatus for a developing device. In FIG. 5, reference numeral 24 denotes a developer reservoir which makes effective use of the upper space of the charger and the cleaner of the adjacent image forming unit. In this image forming unit, the capacity of the developer reservoir can be increased, and even when four units are arranged, the image forming unit can be taken out alone in the direction of arrow E in FIG.
The configuration of this unit will be described. In the developer reservoir 24, the particle size is 100 μm, the surface of which is coated with a silicone resin.
Of the two-component developer 17M obtained by mixing the iron powder carrier 15M and the toner 16M, is attached to a developing roller 28 having a magnet 27 inside, and a developer layer is formed by a developer layer thickness regulating member 29, and the photosensitive member 9 is formed. develop. Reference numeral 30 denotes a high-voltage power supply that applies a voltage to the developing roller.

(Embodiment 1) A color electrophotographic apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 illustrates a printer section for forming an image of a color electrophotographic apparatus according to the present invention.

First, in the printer section, four image forming units 8Bk, 8C, 8M and 8Y as image forming means for each color of black, cyan, magenta and yellow are arranged in this order. Here, each image forming unit used the configuration shown in FIG. The operation of each image forming unit will be described with reference to FIG. The photoconductor 9 is moved to the corona charger 11 (applied voltage of -5 k
V, the voltage of the grid 12 −500 V), and −500
V was charged. The laser beam scanning light 1 is applied to this photoreceptor 9.
Irradiation No. 3 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -100V. When the photoreceptor 9 on which the electrostatic latent image is formed is passed through the developer 17M, the developer 17 is attracted to the magnet 10 inside the photoreceptor. The developer was collected by the developer collecting electrode roller 25 by magnetic force. The high voltage power supply 20 supplies a voltage of -300 V to the developer collecting electrode roller 25.
400V0-p (800V peak-to-peak) on which a DC voltage was superimposed was applied. As a result, the toner on the photoconductor 9 moves between the photoconductor 9 and the developer collecting electrode roller 25 while moving by receiving the electrostatic force and the magnetic force at the same time. The statue remained. The toner adhered on the developer collecting electrode roller 25 was scraped off by the scraper 21 and returned to the developer reservoir 24 again to be used for the next image formation. Thus, a magenta toner image was obtained on the photoreceptor 9. Other developing devices 8Bk, 8C, 8Y other than magenta
Has the same configuration and performs the same operation.

Referring again to FIG. 1, the configuration of the printer unit will be described. As a whole, the image forming unit can be moved in the horizontal direction by being driven by a moving motor 31 serving as a moving means, and each image forming unit sequentially faces a transfer portion 34 of the transfer / conveying belt 32 slightly pushed up by a belt regulating member 33. In the image forming position 35. In the image forming units 8Bk, 8C, 8M, and 8Y arranged side by side, the black unit 8Bk is arranged at the image forming position as shown in FIG.

Numeral 36 denotes a laser exposure device which generates a laser beam scanning light 13 modulated by a signal input to the printer section, which is reflected by mirrors 37 and 38 to form a first beam.
Is irradiated on the photosensitive member of the image forming unit at the image forming position 35 to form a latent image. In the state of FIG. 1, it acts on the image forming unit 8Bk for black.

Reference numeral 32 denotes a transfer / transport belt made of an endless belt-like polyester film having a thickness of 100 μm.
It is wound around a driving roller 39 and a roller 40, and is configured to be able to reciprocate by adsorbing the transfer paper on its surface. Here, in the present embodiment, the distance between the drive roller 39 and the roller 40 is set to a distance (470 mm) longer than twice the length (210 mm) of the A4 paper in the width direction. At the right end of the transfer conveyance belt, there is provided an adsorption charger 42 for adsorbing the paper sent from the paper supply unit 41 to the transfer conveyance belt. The transfer charger 35 is provided at the transfer unit 35, and the transfer conveyance is provided at the left end. A static eliminator 45 for eliminating static electricity of the sheet which is separated from the belt and sent to the fixing device 44 is arranged. Reference numeral 46 denotes a discharge roller for discharging the sheet after fixing.

In this embodiment, the transfer / conveying belt is made of an insulating polyester film, but may be made of a film made of a semiconductive material in which carbon or the like is dispersed in, for example, polyester or urethane. In this case, it is difficult to accumulate electric charges at the time of charging on the transfer / conveying belt, so that the superimposed transfer is further facilitated.

When the paper has to be jammed and removed in the apparatus, the four image forming units are moved to the right end (shown in FIG. 1) at the time of paper jam at the portion F in FIG. It may be moved to the left end for processing. The above is the description of the main configuration of the electrophotographic apparatus of the present invention.

Next, the operation of this apparatus when forming an A4 size color image will be described. A4 paper (not shown) is fed from the paper feeding unit 41 in the short side direction, is attracted to the transfer / transport belt 32 by the action of the attraction charger 42, and is placed on the transfer / transport belt to form an image in the image forming unit. It is moved in the left direction (hereinafter referred to as forward direction) at the same speed. At this time, since the sheet is securely attracted to the transfer / conveying belt 32, the position of the transfer / conveying belt and the sheet does not deviate from each other even when the transfer / conveying belt is reciprocated as described later. Easy to match.

First, the image forming unit is at the position shown in FIG. 1, and the black image forming unit 8Bk
5 faces the transfer section 34. From the right side of the figure, the timing of the paper conveyed on the transfer conveyance belt 32 is adjusted,
The black signal light is input to the image forming unit 8Bk by the laser exposure device 36, and an image is formed with black toner.
At this time, the image forming speed of the image forming unit 8Bk (equal to the peripheral speed of the photoconductor) and the moving speed of the transfer conveyance belt are set to be the same. The black toner image is transferred to the transfer paper by the operation of the transfer charger 43. Immediately after all the black toner images have been transferred and the trailing edge of the sheet has passed the transfer section, the movement of the transfer conveyance belt 32 is temporarily stopped, and then the transfer conveyance belt 32 is moved in the opposite direction (hereinafter referred to as the opposite direction). Move at a speed greater than the forward speed. At this time, the leading edge of the paper is
Since the length 2 is sufficiently long, it stops just before the drive roller 39 and does not peel off from the transfer / transport belt.

On the other hand, almost simultaneously with the start of the reverse movement of the transfer conveyance belt, the image forming unit groups 8Bk, 8C, 8M, 8
The whole Y is driven by the moving motor 31 and moves integrally to the left in FIG. At this time, the image forming unit 8C reaches the image forming position 35 immediately after the sheet moves in the reverse direction and the trailing end of the sheet passes through the transfer section 34, and the moving speed of the transfer conveying belt 32 in the reverse direction and the image forming Set the unit travel time. The trailing edge of the paper passes rightward through the transfer unit 34,
After the image forming unit 8C arrives at the image forming position 35, the transfer / conveyance belt 32 is again moved in the forward direction at a constant speed. As before, the laser exposure device 36 inputs the cyan signal to the image forming unit 8C to form and transfer a cyan toner image. At this time, the start of the movement of the transfer conveyance belt 32 is controlled such that the next cyan toner image matches the black toner image on the sheet with respect to the start of signal light writing.

The above operation is similarly performed for magenta and yellow, and a color image is formed by superimposing the four color toner images on the transfer paper so as to coincide with each other. After the transfer of the last yellow toner image, the transfer / conveyance belt 32 is moved in the forward direction as it is, and the transfer paper on which the color image has been formed is separated from the transfer / conveyance belt 32 while the charge is removed by the charge remover 45. The toner image is fixed by 44 and finally discharged out of the apparatus via a discharge roller 46.

The driving roller 3 of the transfer / conveying belt 32
The distance between the roller 9 and the roller 40 is the same as that in FIG.
Is set to be longer than seven-fourths of the total length in the horizontal direction, so that even if the image forming unit group moves integrally until each of the image forming units reaches the image forming position, It does not correspond to 42 and the static eliminator 45. The above is the description of the operation in the A4 color mode of the electrophotographic apparatus of the present embodiment.

Next, the operation in the monochrome mode will be described. In the single-color mode, the image forming unit of a predetermined color is first moved to the image forming position 35 before the transfer paper reaches the transfer position. Next, image formation and transfer of a predetermined color are performed in the same manner as before.
Continues to move in the forward direction and is fixed. Therefore, in the monochromatic mode, it is a feature of the color electrophotographic apparatus of the present invention that it is possible to use even A3 paper having a size of A4 or more, for example.

The above is the description of the configuration and operation of the first embodiment. (Embodiment 2) Another embodiment will be described with reference to FIG.
The configuration of the image forming unit is different from that of the first embodiment. Image forming units 8Bk, 8C, 8M as four sets of image forming means for each color of black, cyan, magenta, and yellow are provided in the printer unit.
8Y are arranged side by side. The image forming unit had the configuration shown in FIG. The operation will be described below with reference to FIG.
The photoreceptor 9 was charged to −500 V by a corona charger 11 (applied voltage: −5 kV, voltage of grid 12 −500 V). The photosensitive member 9 was irradiated with laser beam scanning light 13 to form an electrostatic latent image. This electrostatic latent image was developed by a developing roller 28 carrying M developer 17M. At this time, a DC voltage of -400 V was applied to the developing roller 28 by the high voltage power supply 30. Other developing devices 8Bk, 8C, 8Y other than magenta
Has the same configuration and performs the same operation.

Referring again to FIG. 6, the configuration of the printer unit will be described. Image forming units 8B arranged side by side
k, 8C, 8M, and 8Y can be moved in the horizontal direction by being driven by a moving motor 31 as a moving means as a whole, and each image forming unit is sequentially moved by the belt regulating member 33 of the transfer / transport belt 32.
Accordingly, it can be located at the image forming position 35 facing the transfer unit 34 which has been slightly pushed up. Other configurations are shown in FIG.
The configuration is the same as

An A4 sheet is fed in a short direction from a sheet feeding section 41, and the transfer / conveying belt 32 is operated by the operation of an adsorption charger 42.
While being adsorbed on the transfer / transport belt, and moved in the forward direction at a constant speed. First, the image forming unit 8B for black
k is arranged at the image forming position 35 and is opposed to the transfer unit 34. From the right side of the figure, a black signal light is input to the image forming unit 8Bk by the laser exposure device 36 in synchronization with the timing of the paper conveyed on the transfer conveyance belt 32, and an image is formed by black toner. Immediately after all the black toner images have been transferred and the rear end of the sheet has passed the transfer section, the transfer / conveyance belt 32 is temporarily stopped and then moved in the opposite direction. On the other hand, almost simultaneously with the start of the reverse movement of the transfer conveyance belt, the entire image forming unit group 8Bk, 8C, 8M, 8Y is driven by the moving motor 31 and moves integrally to the left in FIG. Next, a cyan signal is input to the image forming unit 8C to form and transfer a cyan toner image. The same operation is performed for magenta and yellow to superimpose four color toner images on paper to obtain a color image. After the transfer of the last yellow toner image, the transfer conveyance belt 32 moves in the forward direction as it is, and is fixed by the fixing device 44. The above is the description of the configuration and operation of the color electrophotographic apparatus of the second embodiment.

[0041]

According to the present invention, since the images of each color are all formed at the same image forming position without using a transfer drum having a complicated structure, accurate color registration can be performed with a simple structure. And the image forming means is completed independently as a single image forming means for each color, so that the structure is simple and the image forming means can be easily replaced for each color. Will also be excellent.

Further, while the capacity of the developer reservoir of each image forming unit is increased, the overall structure is kept small and simple, and the structure of the image forming unit including the photosensitive member and the developing unit is simple and easy to replace. An excellent color electrophotographic apparatus is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a color electrophotographic apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an image forming unit used in the present invention.

FIG. 3 is a configuration diagram of an image forming unit used in the present invention.

FIG. 4 is a configuration diagram of an image forming unit used in the first embodiment of the present invention.

FIG. 5 is a configuration diagram of an image forming unit used in a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a color electrophotographic apparatus according to a second embodiment of the present invention.

FIG. 7 is a schematic view of a conventional color electrophotographic apparatus.

[Explanation of symbols]

 Reference Signs List 8 image forming unit 9 photoreceptor 10 magnet 11 corona charger 13 laser exposure 14/24 developer reservoir 25 electrode roller 20/30 high voltage power supply 32 transfer / transport belt 31 unit moving means 35 image forming position

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-67970 (JP, A) JP-A-3-50572 (JP, A) JP-A-2-135379 (JP, A) JP-A 62-67379 71971 (JP, A) JP-A-1-261673 (JP, A) JP-A-4-147874 (JP, A) JP-A-63-212960 (JP, A) JP-A-5-72866 (JP, A) Shokai 61-167655 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 13/01 G03G 15/01-15/01 117

Claims (6)

(57) [Claims] A plurality of movable image forming means for forming toner images of different colors on the photosensitive member, each comprising a rotating photosensitive member and developing means having a toner of a different color; A transfer conveying means which carries a transfer material, reciprocates, and transfers a toner image on the photosensitive member to the transfer material at the same transfer position; and an identical exposure position corresponding to the transfer position Exposure means for exposing the image at, the plurality of image forming means are arranged adjacently in a horizontal direction, each of the plurality of image forming means at an image forming position corresponding to the transfer position and corresponding to the exposure position And a moving unit for sequentially moving the toner images to the same exposure position, and a color electrophotographic apparatus in which toner images of different colors are superimposed on the transfer material to form a color image and fixed on the transfer material by a heat fixing device. In A color electrophotographic apparatus, wherein the arrangement order of the plurality of image forming units is such that a black image forming unit is arranged at a position closest to the fixing unit in the horizontal direction. 2. A color electrophotographic apparatus according to claim 1, wherein said black image forming means is located at an image forming position when said color electrophotographic apparatus is in an image forming operation standby state. 3. A rotating photoreceptor, a charger for charging the photoreceptor, toner of different colors, a developer reservoir for storing toner, and a developing device for developing the photoreceptor with the toner, A cleaner for cleaning the photoconductor,
A plurality of image forming means for forming toner images of different colors on the photoreceptor, carrying a transfer material and reciprocating, and transferring the toner image on the photoreceptor to the transfer material at the same transfer position A transfer conveyance unit having a transfer unit that performs image transfer, an exposure unit that performs image exposure at the same exposure position corresponding to the transfer position, and the plurality of image forming units are horizontally arranged side by side,
Moving means for sequentially moving each of the plurality of image forming means to an image forming position corresponding to the transfer position and corresponding to the exposure position, and superimposing toner images of different colors on the transfer material. A color electrophotographic apparatus for transferring and forming a color image to obtain a color image on the transfer material, wherein a part of a developer reservoir of the image forming means is arranged in a space above the charger of an adjacent image forming means. A color electrophotographic apparatus characterized by using a color image. 4. A rotating photoreceptor, a charger for charging the photoreceptor, toner of different colors, a developer reservoir for storing toner, and a developer for developing the photoreceptor with the toner, A cleaner for cleaning the photoconductor,
A plurality of image forming means for forming toner images of different colors on the photoreceptor, carrying a transfer material and reciprocating, and transferring the toner image on the photoreceptor to the transfer material at the same transfer position A transfer conveyance unit having a transfer unit that performs image transfer, an exposure unit that performs image exposure at the same exposure position corresponding to the transfer position, and the plurality of image forming units are horizontally arranged side by side,
Moving means for sequentially moving each of the plurality of image forming means to an image forming position corresponding to the transfer position and corresponding to the exposure position, and superimposing toner images of different colors on the transfer material. A color electrophotographic apparatus for transferring and forming a color image to obtain a color image on the transfer material, wherein a part of a developer reservoir of the image forming unit is arranged in a space above the cleaner of an adjacent image forming unit. A color electrophotographic apparatus characterized in that the apparatus is used. 5. A plurality of movable image forming means, each comprising a rotating photoreceptor and developing means having a toner of a different color, forming a plurality of toner images of different colors on the photoreceptor. A transfer conveying means which carries a transfer material, reciprocates, and transfers a toner image on the photosensitive member to the transfer material at the same transfer position; and an identical exposure position corresponding to the transfer position Exposure means for image exposure in, the plurality of image forming means are adjacently juxtaposed in the horizontal direction,
Moving means for sequentially moving each of the plurality of image forming means to an image forming position corresponding to the transfer position and corresponding to the exposure position, and superimposing toner images of different colors on the transfer material. A color electrophotographic apparatus for transferring and forming a color image to obtain a color image on the transfer material, wherein each of the adjacent image forming means has a shape capable of being independently taken out obliquely upward. Photo equipment. 6. A color electrophotographic apparatus according to claim 4, wherein said image forming means has a substantially parallelogram side surface.