JPH04293062A - Full color electrophotographic copying device - Google Patents

Abstract

PURPOSE:To improve the transfer efficiency of a toner image and to make a copying speed high in the case of black-and-white copying. CONSTITUTION:In the case of full color copying, reflected light from an original is made incident on a photosensitive body 2 through a 4th reflection mirror 8 and a 5th reflection mirror 9, and the toner image formed on the photosensitive body 2 is transferred to a paper through an intermediate transfer belt 16. In the case of black-and-white copying, the reflected light from the original is made incident on the photosensitive body 2 directly from the 4th reflection mirror 8, the photosensitive body 2 is reversely rotated, and the toner image formed on the photosensitive body 2 is transferred to the paper directly from the photosensitive body 2 by a transfer charger 19.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-color electrophotographic apparatus capable of forming, for example, black-and-white monochrome images and full-color images.

0002

2. Description of the Related Art A full-color copying machine, which is a conventional full-color electrophotographic device, is capable of copying, for example, black and white monochrome originals and color originals, and is configured as shown in FIG. .

In the above-mentioned full-color copying machine, when performing full-color copying, the light source lamp 102 of the optical system 101 scans the full-color original placed on the original platen 103 three times, and each scan The reflected light from the original document passes through each of the three color filters of red, green, and blue in the color separation filter 104 and irradiates the belt-shaped photoreceptor 105, forming an electrostatic latent image on the photoreceptor 105. Ru. Each electrostatic latent image obtained through three exposures is
The toner images are individually developed using color toners, which are yellow, magenta, and cyan developers, in the developing devices 106 , 107 , and 108 , and the resulting toner images are superimposed on the intermediate transfer belt 110 . transcribed. The toner image on the intermediate transfer belt 110 is transferred to paper supplied from the paper feed cassette 111, 112, or 113, and then this toner image is transferred to the fixing device 11.
By thermally fixing the image to the paper in step 4, a full-color copy image is obtained on the paper.

[0004] Furthermore, when making black-and-white copies, the photoreceptor 105 is exposed by one scan by the optical system 101, and the electrostatic latent image is developed with black toner in the developing device 109. The image is similarly transferred to intermediate transfer belt 110 and from there to a sheet of paper. The toner image on the sheet of paper is similarly thermally fixed by the fixing device 114 to obtain a black and white copy image on the sheet of paper.

[0005]

[Problems to be Solved by the Invention] However, with the above-mentioned conventional configuration, in the case of full-color copying, it is unavoidable due to the method of superimposing the toner images of each color on the intermediate transfer belt 110, but in the case of black-and-white copying, Intermediate transfer belt 110
Since the toner image on the photoreceptor is transferred to the paper via the photoreceptor, the efficiency of transferring the toner image to the paper decreases in black-and-white copying, and as a result, the amount of toner consumed increases. Further, in black and white copying, there is a problem in that the copying speed decreases.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, a full-color electrophotographic apparatus according to the invention of claim 1 is provided, in which light is applied to a rotating photoreceptor charged to a predetermined potential through a plurality of reflecting mirrors. an exposure optical system that forms an electrostatic latent image corresponding to an image to be formed on the surface of the photoreceptor by irradiating the photoreceptor with light, a photoreceptor driving means that rotates the photoreceptor, and a photoreceptor drive means that rotates the photoreceptor; a photoreceptor charging means for charging to a predetermined potential;
A monochrome developing means that develops the electrostatic latent image formed on the surface of the photoreceptor with a monochrome developer, and a monochrome developing means that develops the electrostatic latent image formed on the surface of the photoreceptor with a developer of each color necessary for forming a full color image. and intermediate transfer means that transfers a developer image formed on the surface of a photoreceptor to an intermediate transfer member, and then transfers the image from the intermediate transfer member to paper, thereby producing a full color image on the paper. When forming a full-color image, the photoreceptor is rotated by the photoreceptor driving means and charged to a predetermined potential by the photoreceptor charging means, and the color components of the image to be formed are detected by the exposure optical system. Separately, an exposure operation is performed multiple times, and each electrostatic latent image formed on the surface of the photoreceptor by this exposure operation is individually developed with a developer of each color by a full-color developing means. In a full-color electrophotographic apparatus in which a developer image obtained by each developing operation is transferred by an intermediate transfer means to a sheet of paper fed from a paper feed section via an intermediate transfer body, the following measures are taken. .

That is, the monochromatic developing means is provided in a direction opposite to the rotational direction of the photoreceptor during full-color image formation with respect to the photoreceptor charging means, and includes a reflecting mirror moving means for moving the reflecting mirror; A developer is provided along the outer circumferential surface of the photoreceptor in a direction opposite to the rotational direction of the photoreceptor during full-color image formation with respect to the above-mentioned monochrome developing means, and is used to transfer the developer image on the surface of the photoreceptor to paper. an image transfer means, a first paper feed path for transporting the paper in the paper feed section between the photoreceptor and the developer image transfer means, and an intermediate transfer member for transporting the paper in the paper feed section;
a second paper feed path for transporting the developer image onto the paper to a transfer position;
A paper feed direction switching means for switching the paper conveyance direction of the paper feed section between the first paper feed path and the second paper feed path, and a The reflector driving means is controlled so that the optical path from the light source to the photoreceptor is formed using different numbers of reflection mirrors and the same optical path length, and the photoreceptor is rotated in opposite directions during both image formation. The developer image on the surface of the photoreceptor is transferred to the paper via an intermediate transfer member when forming a full color image, and directly transferred to the paper by the developer image transfer means when forming a monochrome image. The intermediate transfer means and the developer image transfer means are controlled so that the paper fed from the paper feed section is transported by the first paper feed path when forming a full color image, and transported by the second paper feed path when forming a monochrome image. and control means for controlling the paper feeding direction switching means so that the paper feed direction switching means is controlled.

In order to solve the above-mentioned problem, the full-color electrophotographic apparatus according to the invention of claim 2 takes the following measures in the full-color electrophotographic apparatus according to the invention according to claim 1.

That is, a full-color fixing means for fixing the full-color developer image on the paper to the paper is provided in the paper conveyance direction from the intermediate transfer means, and a full-color fixing means for fixing the full-color developer image on the paper is provided in the paper conveyance direction from the photoreceptor. A single-color fixing means is provided for fixing the above single-color developer image onto the paper, and the control means operates such that the full-color fixing means operates when a full-color image is formed, and the single-color fixing means operates when a single-color image is formed. Next, the full-color fixing means and the single-color fixing means are controlled.

0010

According to the structure of claim 1, when a full-color image is formed, the exposure optical system applies the image to be formed to the photoreceptor which is rotated by the photoreceptor driving means and charged to a predetermined potential by the photoreceptor charging means. Exposure operations are performed multiple times for each color component, and each electrostatic latent image formed on the surface of the photoreceptor by this exposure operation is individually developed using a developer of each color by a full-color developing means. . The developer image obtained by each of these developing operations is transferred by intermediate transfer means to a sheet of paper fed from a paper feed section via an intermediate transfer body. At this time, the sheet is fed from the sheet feeding section through the first sheet feeding path by the operation of the sheet feeding direction switching means.

On the other hand, when forming a monochromatic image, the exposure optical system performs one exposure operation on the photoreceptor, and the electrostatic latent image formed thereby is developed with a monochromatic developer.

At this time, the photoreceptor, which is rotated by the photoreceptor driving means, rotates in a direction opposite to that during full-color image formation. In addition, in the exposure optical system, the reflecting mirror is driven by the reflecting mirror driving means, so that the number of reflecting mirrors differs by one from the light source to the photoreceptor with the same optical path length compared to when forming a full-color image. A light path is formed.

[0013] Therefore, an electrostatic latent image, that is, a developer image, is formed on the photoreceptor, which is the inverse of the image to be formed when a full-color image is formed. This developer image is directly transferred onto the paper by a developer image transfer means. At this time, the sheet is fed from the sheet feeding section through the second sheet feeding path by the operation of the sheet feeding direction switching means. In addition, since the developer image on the paper is reversely transferred from the photoreceptor,
The image will be the same as the image to be formed.

As mentioned above, in this full-color electrophotographic apparatus, when forming a monochrome image, the developer image on the photoreceptor is transferred directly from the photoreceptor to the paper without going through an intermediate transfer member, so that the transfer rate is high. Efficient transfer is possible, and the image forming speed is increased.

According to the structure of claim 2, in the full-color electrophotographic apparatus according to claim 1, the full-color fixing means operates when a full-color image is formed, and the monochrome fixing means operates when a monochrome image is formed. In addition to the effect described in item 1, control over the fixing means can be simplified. In other words, if you want to obtain a good image using the same fixing means when forming a full-color image and when forming a monochrome image, for example, fixing It is necessary to control the fixing means so that the temperature or fixing speed becomes the optimum value for each image formation, and the control over the fixing means becomes complicated. On the other hand, if a full-color fixing means used when forming a full-color image and a single-color fixing means used when forming a single-color image are provided, there is no need to perform the above-mentioned complicated control.
Control can be simplified.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

A full-color copying machine (hereinafter simply referred to as a copying machine), which is a full-color electrophotographic apparatus, has a transparent original table 1 on its upper side, as shown in FIG. An exposure optical system 3 is arranged below the document table 1 to scan the document placed on the document table 1 and expose a photoreceptor 2, which will be described later. The exposure optical system 3 includes a light source lamp 4 that irradiates light onto an original placed on an original placing table 1, and first to fifth reflecting mirrors 5 that guide reflected light from the original onto the photoreceptor 2.
9, a color separation filter 10 having color filters for the three primary colors of red, green and blue, and an imaging lens 11 disposed in the optical path of the reflected light. The above fourth reflecting mirror 8
As will be described later, it is driven by a reflecting mirror driving device 22 serving as a reflecting mirror moving means, and is movable between a full-color copying position M1 and a black-and-white copying position M2.

That is, as shown in FIG. 2, the fourth reflecting mirror 8 is attached to a rotating shaft 24 via a reflecting mirror support member 23, and is rotatable. The above reflecting mirror support member 23
When it is ON, the reflector support member 23, that is, the fourth reflector 8 is moved against the spring force of the fourth reflector return spring 26,
Fourth reflector drive solenoid 2 that rotates clockwise
5 and a fourth reflecting mirror return spring 26 that pulls the fourth reflecting mirror 8 to rotate counterclockwise. Further, in the clockwise and counterclockwise directions of the reflecting mirror support member 23, the fourth reflecting mirror 8 is located at a full-color copying position M1 shown by a solid line in the figure and a black-and-white copying position M2 shown by a two-dot chain line, respectively. Finely adjustable stoppers 27 are provided for positioning. In this embodiment, the above-mentioned reflecting mirror support member 23, rotating shaft 24, and the fourth
A reflecting mirror driving device 22 is constituted by the reflecting mirror driving solenoid 25, the fourth reflecting mirror return spring 26, and the stoppers 27.

The above full-color copying position M1 in the fourth reflecting mirror 8 is a position where the reflected light from the original is reflected so as to be incident on the photoreceptor 2 via the fifth reflecting mirror 9, as shown in the figure. The black-and-white copying position M2 is a position where the reflected light from the original is reflected from the fourth reflecting mirror 8 so as to be directly incident on the photoreceptor 2. At these full-color position M1 and black-and-white copy position M2 in the fourth reflecting mirror 8,
The optical path lengths from the light source lamp 4 to the photoreceptor 2 are set to be the same. That is, full color copying position M1
The optical path length d1 + from the fourth reflecting mirror 8 to the photoreceptor 2
d2, and the optical path length d from the fourth reflecting mirror 8 at the full-color copying position to the fourth reflecting mirror 8 at the black-and-white copying position M2.
3 plus the optical path length d4 from the fourth reflecting mirror 8 located at the black-and-white copying position M2 to the photoreceptor 2 d3 + d4
The relationship is set to be d1 + d2 = d3 + d4.

A drum-shaped photoreceptor 2 is provided below the exposure optical system 3, as shown in FIG. The photoreceptor 2 is driven by a photoreceptor driving device 28, which will be described later, and is rotatable in clockwise and counterclockwise directions. Around the photoreceptor 2, there is a second photoreceptor charging means for charging the photoreceptor 2 to a predetermined potential in a counterclockwise direction with respect to the incident position of the reflected light from the document onto the photoreceptor 2.
A main charger 12 and three developing tanks 13 to 15 as full-color developing means that individually accommodate toners as color developers of yellow, magenta, and cyan, which are complementary colors of each color filter in the color separation filter 10.
, an intermediate transfer device 17 as an intermediate transfer means, a static elimination charger 18, and a transfer charger 1 as a developer image transfer means.
9. A developer tank 20 as a monochrome developing means containing black toner, and a first main charger 21 as a photoreceptor charging means are provided.

The intermediate transfer device 17 described above includes two transfer guide rollers 29 and 29 facing the photoconductor 2, a drive roller 30, an electrode roller 31, an idle roller 32, and an intermediate transfer roller supported by these rollers and rotated. It includes an intermediate transfer belt 16 as a transfer body, a cleaning device 33, and a transfer roller 34 provided opposite to the electrode roller 31.

The above transfer guide rollers 29, 29 are provided at the upper end of the roller support member 35, as shown in FIG. This roller support member 36 is rotatable around a support shaft 37. The roller support member 36 includes a support member drive solenoid 3 that rotates the roller support member 36 against the spring force of a support member drive spring 39 so that the intermediate transfer belt 16 moves to a position where the transfer operation can be performed.
8 and a support member drive spring 39 that pulls the roller support member 36 so that the roller support member 36 rotates in the opposite direction to this direction.

The roller support member 36 is formed with an engaging convex portion 36a, and a stopper 40 is formed on the engaging convex portion 36a.
The engagement recess 40a is adapted to engage with the engagement recess 40a. The stopper 40 is rotatably provided around a support shaft 41. The stopper 40 includes a stopper drive solenoid 43 that rotates the stopper 40 in a direction to release the engagement between the engagement protrusion 36a and the engagement recess 40a against the spring force of the stopper drive spring 42; A stopper drive spring 42 is connected to the stopper drive spring 42 which pulls the stopper 40 so that the stopper 40 rotates in the opposite direction. Further, a tapered portion 40b is formed at the sliding contact side portion of the engagement protrusion 36a with respect to the engagement recess 40a, which facilitates engagement of the engagement protrusion 36a with the engagement recess 40a.

With the above-described structure, the engaging convex portion 36a of the roller support member 36 and the engaging concave portion 40a of the stopper 40
When the solenoids 38 and 43 are both OFF, the intermediate transfer belt 16 is moved toward the transfer guide roller 29.
29 so that it is placed at the full-color copying position B1 for full-color copying, where it faces the photoreceptor 2 and is capable of transfer operation.

Furthermore, when the stopper drive solenoid 43 is turned ON from this state, the stopper 40 is driven by the stopper drive solenoid 43, and the engagement concave portion 40a of the stopper 40 and the engagement convex portion of the roller support member 36 are driven by the stopper drive solenoid 43. 36a, and the roller support member 36 is driven by the support member drive spring 39 and transfers the transfer guide rollers 29 and 2.
9 is rotated in a direction to separate it from the photoreceptor 2, thereby moving the intermediate transfer belt 16 to the monochrome copying position B2. Note that this state is maintained even if the stopper drive solenoid 43 is subsequently turned off. The black-and-white copying position B2 is located between the neutralization charger 18 and the transfer charger 1, which are moved to the position of the intermediate transfer belt 16 as described later when the intermediate transfer belt 16 performs black-and-white copying.
In order to avoid interference with photoconductor 9, this position is spaced apart from photoreceptor 2 and moved downward.

Further, when the intermediate transfer belt 16 is at the black-and-white copying position B2 and the support member drive solenoid 38 is turned on from the OFF state of the stopper drive solenoid 43, the stopper 40 is driven by the stopper drive spring 42. Then, the engagement recess 40a is rotated in a direction to bring it into contact with the roller support member 36, and the roller support member 36 is rotated.
Driven by the support member drive solenoid 38, the intermediate transfer belt 16 is moved to the photoreceptor 2 by the transfer guide rollers 29.
The intermediary transfer belt 16 is rotated in a direction in which it makes contact with the roller support member 36, and the engaging convex portion 36a of the roller support member 36 overcomes the tapered portion 40a of the stopper 40 and engages with the engaging concave portion 40a, and the intermediate transfer belt 16 moves to the above-mentioned full color copying position B1. It is now arranged. In addition, in this state, the support member drive solenoid 38 is turned off.
It is retained even if

The idle roller 32 is rotatably provided on a slide member 45 that slides while being guided by a guide member 44. The slide member 45 is slidable in the direction of pulling and loosening the intermediate transfer belt 16, and is pulled in the direction of pulling the intermediate transfer belt 16 by a slide member drive spring 46. This results in
The tensioned state of the intermediate transfer belt 16 is maintained when it is at the full-color copying position B1 and the black-and-white copying position B2.

The roller support member 36, support shaft 37, support member drive solenoid 38, support member drive spring 39, stopper 40, support shaft 41, stopper drive spring 42, stopper drive solenoid 43, guide member 44,
The belt drive device 35 is constituted by the slide member 45 and the slide member drive spring 46.

Further, the static elimination charger 18 and the transfer charger 19 are provided integrally and are driven by a charger drive device 48 shown in FIG. It is supposed to move to . The black-and-white copying position C2 is located near the transfer area where the intermediate transfer belt 16 and the photoreceptor 2 face each other during full-color copying, that is, almost below the photoreceptor 2, and the full-color copying position C1
is the position where both the chargers 18 and 19 have retreated from the black and white copying position C2 toward the developing tank 20.

The charger driving device 48 described above is configured to move both chargers 18 and 19 connected to the timing belt 50 by driving the timing belt 50 with a motor 49. The timing belt 50 is provided at both ends of the chargers 18 and 19 on the front side and the back side of the copying machine, and is connected to a drive pulley 51, a driven pulley 52, and a tension pulley 5, respectively.
It is supported by 3.

[0031] Front side and rear side drive pulleys 51 and 5
1 is attached to a drive shaft 54, and a gear 55 is provided at the end of this drive shaft 54. This gear 55 meshes with a gear 56 provided on the rotating shaft of the motor 49.

On the other hand, two guide rollers 57 and 57 and one belt connecting pin 58 are provided at both ends of both chargers 18 and 19, respectively. - 19 is connected to the timing belt 50. Further, the guide rollers 57 are movably arranged between two roller guides 83 on the inner circumferential side and the outer circumferential side provided along the outer circumference of the photoreceptor 2.

With the structure of the charger drive device 48 as described above, depending on the forward and reverse rotations of the motor 49,
Both chargers 18 and 19 are adapted to move to a full-color copying position C1 and a black-and-white copying position C2. In addition, full color copying position C1 of both chargers 18 and 19
And reaching the black-and-white copying position C2 is determined by a detection plate 59 provided on the timing belt 50 and a first detection plate 59 provided at the position of the detection plate 59 corresponding to the full-color copying position C1.
A sensor 60 and a detection plate 5 corresponding to the black and white copying position C2
The second sensor 61 provided at position 9 is used for detection. The first and second sensors 60 and 61 described above consist of a light-emitting element and a light-receiving element, and position detection is performed by blocking the optical path between them with the detection plate 59. It is not limited to the configuration.

In addition, on the paper feed side of the copying machine, as shown in FIG.
is provided, and this paper feed cassette 62 and intermediate transfer device 17
A first paper feed path 63 is provided between the paper feed cassette 62 and the photoreceptor 2, while a second paper feed path 64 is provided between the paper feed cassette 62 and the photoreceptor 2. At the branch point between the first paper feed path 63 and the second paper feed path 64, there is a switch for switching the paper feeding direction from the paper feed cassette 62 to the first paper feed path 63 side or the second paper feed path 64 side. A gate 65 is provided. This switching gate 65 is driven by a gate drive solenoid 66, which will be described later, and rotates to a full-color copying position G1 for guiding the paper toward the first paper feed path 63 during full-color copying, and rotates the paper to the second paper feeding path G1 during black-and-white copying. Black and white copying position G2 guided to paper path 64
It is designed to rotate. The switching gate 65 and the gate drive solenoid 66 constitute a sheet feeding direction switching means. Also, between the first and second paper transport paths 63 and 64, the switching gate 65, and the cassette mounting section, there are a plurality of transport rollers 6 for transporting the paper.
7... is provided in the cassette mounting section, and a paper feed cassette 6 is provided in the cassette mounting section.
A paper feed roller 68 is provided for feeding out the paper in 2.

A first suction belt 69 and a first fixing device 71 as a full-color fixing means are provided in the paper transport direction from the intermediate transfer device 17, and a similar belt is provided in the paper transport direction from the photoreceptor 2. A second suction belt 70 and a second fixing device 72 as a single color fixing means are provided. The first fixing device 71 includes an upper heat roller 73 and a lower heat roller 74 for thermally fixing the toner image on the paper to the paper.
Similarly, the second fixing device 72 includes an upper heat roller 7.
5 and a lower heat roller 76. The heating temperature for the paper in the first fixing device 71 used for full-color copying, that is, the fixing temperature, is set higher than the fixing temperature of the second fixing device 72 used for black-and-white copying. This is because during black and white copying, one layer of toner image made of black toner is heat-fixed, whereas during full-color copying, it is necessary to heat-fix three layers of toner images made of three color toners.

A transport roller 77 and a paper discharge roller 78 are provided in the paper transport direction of the first fixing device 71 and the second fixing device 72, and the paper that has been thermally fixed by these rollers 77 and 78 is transferred to the copying machine. It is designed to be ejected from the machine.

The present copying machine also includes a control device 79 shown in FIG. 5 as a control means consisting of a microcomputer. In addition to normal full-color copying and black-and-white copying, this control device 79 performs operations corresponding to full-color copying and black-and-white copying based on a copy mode command signal that instructs full-color copying or black-and-white copying. , the exposure optical system 3, the fourth reflecting mirror driving solenoid 25 of the reflecting mirror driving device 22, the photoconductor driving device 28 as a photoconductor driving means for rotating the photoconductor 2, the first main charger 21, and the second main charger. 12,
Developer tanks 13 to 15, developer tank 20, static elimination charger 18,
Transfer charger 19, intermediate transfer device 17, support member drive solenoid 38 and stopper drive solenoid 43 of belt drive device 35, motor 49 of charger drive device 48,
A gate drive solenoid 66, a first fixing device 71, a second fixing device 72, and a conveyance roller 6 for conveying paper.
7/77, paper feed roller 68, first/second suction belt 69
- A paper transport system 80 consisting of a paper ejection roller 70, a paper ejection roller 78, etc. is controlled as described below.

In this embodiment, the above copy mode command signal is input to the control device 79 by operating a copy mode selection key 80 for selecting full color copying or black and white copying.

It should be noted that as another configuration for obtaining the copy mode command signal, for example, the exposure optical system 3 may include a CCD (chamber)
A sensor for detecting the color of the original such as a rge coupled device) sensor is provided, and when the copy start button 81 is turned on, a preliminary operation of the original is performed using the light source lamp 4, and the reflected light is transmitted to, for example, the first to fifth By driving any of the reflecting mirrors 5 to 9, the input is input to a sensor for detecting the original color provided outside the regular optical path, and from the output of this sensor, an RGB signal indicating the original color is sent to the control device 79. The result of the detection and the determination as to whether the original is a color original or a black and white original can also be used as a copy mode command signal.

In the above configuration, the operation of the copying machine under the control of the control device 79 for full-color copying and black-and-white copying will be described below.

When full-color copying is selected by the copy mode selection key 80, the fourth reflecting mirror drive solenoid 25 is turned on in the reflecting mirror driving device 22 of the exposure optical system 3.
N, the fourth reflecting mirror 8 moves to the full color copying position M1.
Move to. In the belt drive device 35 of the intermediate transfer device 17, the stopper drive solenoid 43 is turned off and the support member drive solenoid 38 is turned on, so that the intermediate transfer belt 16 moves to the full-color copying position B1 facing the photoreceptor 2. . In the charger drive device 48, the electric discharge charger 18 and the transfer charger 19 are driven by the motor 49 to move to the upper position, ie, the full-color copying position C1. The first paper feed path 63 and the second paper feed path 6
4, a switching gate 65 is driven by a gate drive solenoid 66 to transfer the paper to the first paper feed path 6.
Rotates to full color copying position G1, which guides in three directions.

Next, when the copy start button 81 is turned on, the photoconductor 2 is driven by the photoconductor driving device 28 and rotates counterclockwise in FIG. The surface of the photoreceptor 2 is charged to a predetermined potential. On the other hand, in the exposure optical system 3, the light source lamp 3a irradiates the original placed on the original placing table 1 with light, thereby scanning the original three times. The reflected light from the document during each of these document scans enters the color separation filter 10 via the first to third reflecting mirrors 5 to 7, and is separated into color components by the color separation filter 10. This light further passes through the imaging lens 11 , is reflected by the fourth reflecting mirror 8 toward the fifth reflecting mirror 9 , and enters the photoreceptor 2 via the fifth reflecting mirror 9 . As a result, the photoreceptor 2 is exposed to light, and electrostatic latent images are formed on the photoreceptor 2 by color components corresponding to the image of the document.

Each of the electrostatic latent images described above is developed and visualized in developer tanks 13 to 15 using yellow, magenta, and cyan toners that are complementary colors of each color filter in the color separation filter 10, and becomes a toner image. . These toner images for each color component are transferred to the intermediate transfer belt 16 by transfer guide rollers 29, 29 in the intermediate transfer device 17.
are transferred so that they overlap at the same position.

Further, the paper in the paper feed cassette 62 is sent out from the paper feed cassette 62 by a paper feed roller 68.
The paper is guided in the direction of the first paper feed path 63 by the switching gate 65 and sent between the electrode roller 31 and the transfer roller 34 through the first paper feed path 63 .

[0045] Then, the electrode roller 31 and the transfer roller 34
As a result, the toner image on the intermediate transfer belt 16 is transferred to the paper. This paper is transferred to the first suction belt 69 by the first suction belt 69.
The toner image on the paper is sent to a fixing device 71, and in the first fixing device 71, the toner image on the paper is heated by an upper heat roller 73 and a lower heat roller 74, and is thermally fixed to the paper. As a result, a full-color copy image is obtained on the paper. This paper is then discharged out of the copying machine by conveyance rollers 77 and paper discharge rollers 78.

On the other hand, when black and white copying is selected using the copy mode selection key 80, the fourth reflecting mirror driving solenoid 25 is turned OFF in the reflecting mirror driving device 22.
The fourth reflecting mirror 8 moves to the monochrome copying position M2. In the belt drive device 35, a stopper drive solenoid 43
is turned on, and the support member drive solenoid 38 is turned off, and the intermediate transfer belt 16 moves to the black and white copying position B2, which is spaced downward from the photoreceptor 2. In the charger driving device 48, the electric discharge charger 18 and the transfer charger 19 are driven by a motor 49 to move to a black and white copying position C2 which is a lower position. At the branching part between the first paper feed path 63 and the second paper feed path 64, a switching gate 65
is driven by the gate drive solenoid 66 to rotate to the black and white copying position G2 where the paper is guided in the direction of the second paper feed path 64.

Next, when the copy start button 81 is turned on, the photoconductor 2 is driven by the photoconductor driving device 28, as shown in FIG. 6, and rotates clockwise in the same figure. The operation of the charger 12 charges the surface of the photoreceptor 2 to a predetermined potential.

In the exposure optical system 3, the original is scanned once.
The reflected light from the original passes through the first to third reflecting mirrors 5 to 7 and the imaging lens 11, and reaches the fourth reflecting mirror 8 without passing through the color separation filter 10. The reflected light from the original that is incident on the fourth reflecting mirror 8 is guided so as to be directly incident on the photoreceptor 2, and the photoreceptor 2 is exposed.

Further, the paper in the paper feed cassette 62 is guided toward the second paper feed path 64 by the switching gate 65.
The paper is sent between the static elimination charger 18 and transfer charger 19 and the photoreceptor 2 through the second paper feed path 64 . Then, the toner image on the photoconductor 2 is transferred to the paper by the transfer charger 19, and the paper is peeled off from the photoconductor 2 by the transfer charger 18. This paper is transferred to the second suction belt 70
The toner image on the paper is then sent to the second fixing device 72, where the toner image on the paper is heated by upper and lower heat rollers 73 and 74 and thermally fixed on the paper. As a result, a black and white copy image is obtained on the paper. This paper is then discharged out of the copying machine by conveyance rollers 77 and paper discharge rollers 78.

In this embodiment, two fixing devices, a first fixing device 71 and a second fixing device 72, are provided for full-color copying and black-and-white copying, respectively. There is one device, and in order to perform good fixing for full-color copying and black-and-white copying, the fixing temperature setting value for this fixing device is changed according to each copying. A configuration may also be adopted in which the fixing temperature is controlled to be higher than the fixing temperature during black-and-white copying. Alternatively, the fixing temperature may be the same during both copying, and the fixing speed during full-color copying may be controlled to be slower than the fixing speed during black-and-white copying by rotating the heat roller at a low speed.

Further, in this embodiment, the first main charger 21 and the second main charger 12 are provided, but only one main charger is provided, and this main charger is used during full-color copying and black-and-white copying. It is also possible to adopt a configuration in which the light reflected from the document is incident on the side of the charger in the rotation direction of the photoreceptor.

[0052]

Effects of the Invention As described above, in the full-color electrophotographic apparatus of the invention according to claim 1, the monochrome developing means rotates the photoreceptor charging means in a direction opposite to the rotational direction of the photoreceptor during full-color image formation. a reflecting mirror moving means for moving the reflecting mirror; and a reflecting mirror moving means provided along the outer peripheral surface of the photoreceptor in a direction opposite to the rotation direction of the photoreceptor during full-color image formation with respect to the monochrome developing means. , a developer image transfer means for transferring a developer image on the surface of the photoreceptor onto paper; a first paper feed path for conveying the paper in the paper feed section between the photoreceptor and the developer image transfer means; and a paper feed section. A second paper feed path that transports the paper to a transfer position of the developer image onto the paper in the intermediate transfer body, and a paper feed section that transports the paper in the direction between the first paper feed path and the second paper feed path. The optical path from the light source to the photoreceptor is formed by the number of reflecting mirrors that differ by only one and the same optical path length during both full-color image formation and monochrome image formation. The reflecting mirror driving means is controlled so that the photoreceptor rotates in the opposite direction when forming both images, and the developer image on the surface of the photoreceptor is rotated in the opposite direction when forming a full color image. The intermediate transfer means and the developer image transfer means are controlled so that the developer image transfer means is transferred to the paper via the intermediate transfer member, and when a monochrome image is formed, the developer image transfer means is transferred directly to the paper, and the developer image transfer means is supplied from the paper feed section. The control means controls the paper feed direction switching means so that the paper is transported by the first paper feed path when forming a full-color image and is transported by the second paper feed path when forming a monochrome image. .

[0053]Thus, although it has a configuration capable of forming a full-color image, when forming a monochrome image, the developer image on the photoreceptor is transferred directly from the photoreceptor to the paper without going through an intermediate transfer member. Therefore, the developer image on the photoreceptor can be transferred to paper with high transfer efficiency. As a result, the amount of developer consumed during monochrome image formation can be reduced.

[0054] Further, there are effects such as being able to increase the image forming speed when forming a monochrome image.

As described above, the full-color electrophotographic apparatus of the invention according to claim 2 is the full-color electrophotographic apparatus according to claim 1, in which the full-color developer on the paper is A full-color fixing means for fixing the image on the paper is provided, and a monochrome fixing means for fixing the monochrome developer image on the paper to the paper is provided in the paper conveyance direction from the photoreceptor, and the above-mentioned control means The full-color fixing means and the single-color fixing means are controlled so that the full-color fixing means operates during full-color image formation, and the single-color fixing means operates during monochrome image formation.

Accordingly, in addition to the effect of the invention of claim 1, there is an effect that control over the fixing means can be simplified.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is an overall configuration diagram of a full-color copying machine during full-color copying.

FIG. 2 is an explanatory diagram showing the configuration of a reflecting mirror driving device that drives the fourth reflecting mirror shown in FIG. 1 to a full-color copying position and a black-and-white copying position.

FIG. 3 is an explanatory diagram showing the configuration of a belt driving device that drives the intermediate transfer belt shown in FIG. 1 to a full-color copying position and a black-and-white copying position.

FIG. 4 is an explanatory diagram showing the configuration of the transfer charger shown in FIG. 1 and a charger drive device that drives the transfer charger to a full-color copying position and a black-and-white copying position.

5 is a block diagram showing the configuration of a control system in the full-color copying machine shown in FIG. 1. FIG.

FIG. 6 is an overall configuration diagram of the full-color copying machine shown in FIG. 1 during black-and-white copying.

FIG. 7 is an overall configuration diagram showing a conventional full-color copying machine.

[Explanation of symbols]

2 Photoreceptor 3 Exposure optical system 8 Fourth reflecting mirror 12 Second main charger (photoreceptor charging means)
13 Developer tank (full color developing means) 14
Developer tank (full color developing means) 15 Developer tank (
Full color developing means) 16 Intermediate transfer belt (intermediate transfer body) 17 Intermediate transfer device (intermediate transfer means)
19 Transfer charger (developer image transfer means) 20
Developer tank (monochrome developing means) 21 First main charger (photoreceptor charging means)
22 Reflector drive device (reflector moving means) 25
Fourth reflector drive solenoid 28 Photoconductor drive device (photoconductor drive means) 38 Support member drive solenoid 43 Stopper drive solenoid 48 Charger drive device 49 Motor 62 Paper feed cassette (paper feed section) 63 First paper feed path 64 Second Paper feed path

Claims (2)

[Claims] Claim 1: A rotating photoreceptor charged to a predetermined potential,
An exposure optical system that forms an electrostatic latent image corresponding to the image to be formed on the surface of the photoconductor by irradiating light through multiple reflecting mirrors and exposing the photoconductor, and a photosensitive system that rotates the photoconductor. a photoreceptor charging means for charging the photoreceptor to a predetermined potential; a monochrome developing means for developing an electrostatic latent image formed on the surface of the photoreceptor with a monochrome developer; A full-color developing means develops an electrostatic latent image using a developer of each color necessary for forming a full-color image, and a developer image formed on the surface of a photoreceptor by the developer is once transferred to an intermediate transfer member, and this intermediate It is equipped with intermediate transfer means for transferring from the transfer body to paper, and can form a full-color image and a single-color image on the paper. When forming a full-color image, the photoreceptor is rotated by a photoreceptor driving means and brought to a predetermined potential by a photoreceptor charging means. The exposure optical system performs multiple exposure operations on the charged photoreceptor for each color component of the image to be formed, and each electrostatic latent image formed on the surface of the photoreceptor is exposed in full color. The developing means performs an operation of developing each color individually with developer, and the image of the developer obtained by each developing operation is supplied from the paper feeding section by the intermediate transfer means via the intermediate transfer body. In a full-color electrophotographic device that transfers images onto paper, the above-mentioned monochrome developing means is provided in a direction opposite to the rotational direction of the photoreceptor during full-color image formation with respect to the photoreceptor charging means, and moves the reflecting mirror. A reflecting mirror moving means is provided along the outer circumferential surface of the photoreceptor in a direction opposite to the rotation direction of the photoreceptor during full-color image formation with respect to the monochrome developing means, and is provided along the outer peripheral surface of the photoreceptor, and a developer image on the surface of the photoreceptor is provided. a developer image transfer means for transferring the image to the paper, a first paper feed path for transporting the paper in the paper feed section between the photoreceptor and the developer image transfer means, and an intermediate transfer member for transferring the paper in the paper feed section. The second paper feed path transports the developer image to the transfer position on the paper, and the first paper transport direction in the paper feed section.
A paper feeding direction switching means for switching between the paper feeding path and the second paper feeding path, and a number of reflecting mirrors that differ by only one and the same optical path during both full color image formation and monochrome image formation. The reflecting mirror driving means is controlled so that an optical path from the light source to the photoreceptor is formed by the length of the photoreceptor, and the photoreceptor driving means is controlled so that the photoreceptor rotates in opposite directions during both image formation. An intermediate transfer means and a developer image transfer means are used so that the developer image on the body surface is transferred to paper via an intermediate transfer member when forming a full color image, and directly transferred to paper by the developer image transfer means when forming a monochrome image. and a paper feed direction switching means so that the paper fed from the paper feed section is transported by the first paper feed path when forming a full color image and is transported by the second paper feed path when forming a monochrome image. A full-color electrophotographic apparatus comprising: a control means for controlling the apparatus. 2. A full-color fixing means for fixing the full-color developer image on the paper to the paper is provided in the paper conveyance direction from the intermediate transfer means, and a full-color fixing means for fixing the full-color developer image on the paper is provided in the paper conveyance direction from the photoreceptor. A single-color fixing means is provided for fixing the above single-color developer image onto the paper, and the control means operates such that the full-color fixing means operates when a full-color image is formed;
When forming a single color image, the single color fixing means is activated.
2. The full-color electrophotographic apparatus according to claim 1, wherein the full-color fixing means and the single-color fixing means are controlled.