JPH10307442A - Color image forming device capable of switching color mode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color image forming device capable of switching a color mode from a four-color full color mode to a monochromatic mode and vice versa surely and smoothly, which is miniaturized and is made light in weight and in which rotation unevenness is not caused by the changeover. SOLUTION: One driven gear 31BK of an odd numbered driven gear group and another driven gear 31Y are connected by idle gears 34BK and 34Y, and one driven gear 31M of an even numbered driven gear group and another driven gear 31C are connected by the idle gears 34M and 34C. A rocking unit 1 supported in freely rocking to the center rotary shaft 30BK of the driven gear 31BK is turned by a rocking mechanism part 2. A driving mechanism part and the idle gears 34BK and 34Y and supported to the rocking unit side plate 3 of the rocking mechanism part 2 and the rotation of the driving mechanism part is transmitted only to the driven gear 31BK or to the whole by the turning of the rocking unit side plate 3. Thus, the changeover of a mode is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus for four colors using a tandem system, and more particularly to a color image forming apparatus capable of smoothly switching between a full color mode and a monochrome mode. .

[0002]

2. Description of the Related Art Black (BK), magenta (M), yellow (Y), mainly for the purpose of speeding up image output,
There is a tandem-type color image forming apparatus in which image forming units for four colors of cyan (C) are arranged in a line, and a color image is formed on a recording sheet simply by passing the recording sheet along the conveying direction of the recording sheet. .

FIG. 14 shows this color image forming apparatus 14. As illustrated, the color image forming apparatus 14 includes four image forming units 15BK, 15M, 15Y, and 15C of different colors.
And the recording paper 17 from the paper supply unit 16 to the image forming unit 15BK.
The image forming unit 15B is formed by refracting a laser beam from a laser light source (not shown) by a polygon scanner 19 or a deflecting mirror 20 and the transfer belt 18 that is conveyed to a position where the image is formed.
It is composed of a laser scanner 21 which is incident on the photosensitive member side such as K and exposes the surface thereof, a fixing unit 22 and the like.
In the laser scanner 21, the polygon scanner 19 rotates to perform main scanning in the central rotation axis direction of the photoconductor, and the rotation of the photoconductor sub-scans in the direction orthogonal to the central rotation axis direction of the photoconductor. Scanning is performed.

Image forming units 15BK, 15M, 15Y, 1
Reference numeral 5C designates the photoconductors 23BK, 23M, 23Y and 23C, the laser scanner 21 which is the above-mentioned exposure device, and the developing device 2.
4BK, 24M, 24Y, 24C and charging device 25B
K, 25M, 25Y, and 25C, toner cleaning devices 26BK, 26M, 26Y, and 26C, and transfer device 2.
7BK, 27M, 27Y, 27C, etc. Reference numeral 28 denotes a reading scanner, and reference numeral 29 denotes an image processing circuit.

The surface of the photoconductor 23BK or the like is a charging device 25B.
After being uniformly charged with K or the like, the laser scanner 21 exposes the image to a pattern corresponding to an image to be output, and forms an electrostatic image on the surface of the photoconductor 23BK or the like. This electrostatic image is developed by the developing device 24BK or the like to form a toner image. This toner image is transferred onto the recording paper 17.
The toner remaining on the surface of the photoconductor 23BK or the like after the transfer is removed by the cleaning device 26BK. The transferred recording paper 17 is sequentially fed along the transfer belt 18, separated from the transfer belt 18 by the separation claw 41 at the end portion of the transfer belt 18, and fixed by the fixing unit 22 to the discharge unit (not shown) side. Conveyed.

The alignment of each color is performed by the transfer belt 18 by the photoconductors 23BK, 23M, 23 of the recording paper 17 respectively.
The exposure start time is set by setting the exposure start time so that the timing at which the image on the photoconductors 23BK, 23M, 23Y, and 23C is moved to the transfer position coincides with the timing at which the image is transferred to the photosensitive position of Y, 23C. Will be
For this purpose, each of the photoconductors 23BK, 23M, 23Y, 23
C needs to be driven uniformly.

Each photoconductor 23 for achieving the above object
The drive transmission mechanism connected to the BK, 23M, 23Y, and 23C is shown in FIGS. 15 to 17 and has been filed by the same applicant. Photoconductor 23BK, 23M, 23
Y, a central rotation shaft 30BK for rotationally driving the 23C,
30M, 30Y and 30C have driven gears 31B of the same shape
K, 31M, 31Y and 31C are connected.

In this embodiment, four driven gears 31BK and the like arranged in the order of BK, M, Y, C along the transfer belt conveying direction are odd-numbered driven gears 31BK and 31Y and even-numbered driven gears 31BK and 31Y. The driven gears 31BK and 31C are divided into two groups. As shown in FIGS. 16 and 17, the driven gears 31BK and 31Y and the driven gears 31M and 31C of these groups are used.
Are arranged stepwise along the axial direction of the center rotation shaft 30BK or the like. In addition, each center rotation shaft 30BK etc.
Supported by 2.

Idle gears 34BK / Y and 34M / C
Are respectively supported by a rotary shaft 36 supported by a drive unit side plate 33 supporting the drive mechanism section 35 and a rotary shaft 37 supported by the main body side plate 32. In addition, idle gear 34BK
-Y meshes with driven gears 31BK and 31Y, and idle gear 34M-C meshes with driven gears 31M and 31C.

On the other hand, a drive gear 40 is connected to a drive shaft 39 of a motor 38 which is a drive source of a rotation mechanism portion 35 supported by a drive unit side plate 33, and the drive gear 40 is a driven gear as shown in FIG. It meshes with 31BK and 31M.

With the above structure, the driven gear 31BK and the driven gear 31M rotate via the drive gear 40 by driving the motor 38, and the idle gears 34BK.Y, 34M.C meshing with them rotate. Idle gear 3
When 4BK • Y and 34M • C rotate, driven gears 31Y and 31C meshing with them rotate simultaneously. Therefore, the photoconductors 23BK, 23M, 23Y, 23C
Are simultaneously driven to rotate.

In this embodiment, the odd-numbered driven gear 31
BK, 31Y and even-numbered driven gears 31M, 31C
The driven gear 31B is arranged differently from the group of
K, 31M, 31Y and 31C are all photoconductors 23BK
And 23M, etc., are formed to be larger than the axial distance. Therefore, the banding cycle can be shortened, and high image quality can be achieved.

In the color image forming apparatus 1 having the above-described structure, a full-color image of four colors is formed as described above. However, the color image forming apparatus 1 is not always required to form a full-color image. In some cases, a monochrome mode (black and white) is often required. In this case, only the photoconductor required for the monochrome mode, specifically, only the photoconductor 23BK needs to operate, and the other photoconductors 23M, 2
It is desirable that 3Y and 23C be stopped. In particular, since the cleaning device 26BK and the like are always in contact with the photoconductor 23BK, the abrasion is large. When the cleaning device 26BK and the like wear, the photoconductor 23BK and the like deteriorate, and a high-quality image cannot be obtained. Therefore, it is important to stop the rotation of the photoconductor except when necessary.

A conventional technique for switching between the full-color mode and the monochrome mode based on the above request has already been disclosed, and JP-A-7-181773 can be cited as an example. This "photosensitive drum drive mechanism" is a drive selection member (4) which does not rotate and transmit the rotation to the photoconductor side when the drive motor for driving the photoconductor receives a rotation limiting force of a predetermined value or more.
Is provided to rotate the drive motor to the first or second position in the monochrome mode and the full color mode to selectively transmit the rotation of the drive motor to the photoconductor side. It consists of using a mechanism.

[0015]

According to the above-mentioned known technique, the switching between the full-color mode and the monochrome mode can be smoothly performed. However, as described above, since the transmission path is complicated and long, each photoconductor has the same rotational speed. Makes it difficult to rotate,
In addition, since the gear transmission mechanism and the belt transmission mechanism are provided, there is a problem that transmission loss occurs and rotation unevenness occurs. When the rotation unevenness occurs, banding (striped light-and-shade unevenness) occurs, and is particularly remarkable in a halftone image. 15 and the like have a lower degree of occurrence of the banding as compared with the above-mentioned known technology, but a mechanism for switching between a full-color mode and a monochrome mode is not provided. Means for not rotating other driven gears in the monochrome mode include, for example, the central rotation shafts 30M, 30Y, 30C of the photoconductors 23M, 23Y, 23C and these driven gears 31M,
Means for interposing an attachment / detachment mechanism such as an electromagnetic clutch between 31Y and 31C is conceivable. However, at least three electromagnetic clutches and the like are required, which increases the cost, increases the central rotation axis in the axial direction, and There is a backlash between the electromagnetic clutch shaft and the gear, which may affect the uneven rotation.

The present invention was devised in view of the above circumstances, has a transmission mechanism that does not cause uneven rotation, can smoothly switch between the full-color mode and the monochrome mode, and can be implemented at low cost. An object of the present invention is to provide a color image forming apparatus capable of color mode switching with less adverse effect on uneven rotation due to the switching mechanism.

[0017]

In order to achieve the above object, a color image switchable color image forming apparatus according to claim 1 is a black (BK), magenta (M),
An image forming section of four colors of yellow (Y) and cyan (C) is arranged along the recording paper conveyance direction, and a driven gear supported on a central rotation axis of a photosensitive member of each of the image forming apparatuses; The second driven gear group (BK · Y) and the even-numbered driven gear group (M, C) are arranged while being staggered in the axial direction, and the driven gears in each group are idle gears. And a drive gear that is coupled to one driven gear of the odd-numbered driven gear group and one driven gear of the even-numbered driven gear group adjacent thereto A driving mechanism comprising a driving source, wherein the driving mechanism is supported by the center rotation axis of one of the driven gears in the odd-numbered group so as to be swingable, and holds the driving mechanism. Before engaging with the driven gear A swing unit for supporting the idle gear, and providing a said drive mechanism and the swinging mechanism for the idle gear oscillating the oscillating unit in order to ChakuHanare engagement to other driven gear.

Further, in the color image forming apparatus capable of color mode switching according to the second aspect, the idle gear is to be meshed with the other driven gear between the swing unit and the stationary side of the apparatus. A spring is provided for rotating the swing unit in a direction approaching the other driven gear side.

According to a third aspect of the present invention, there is provided a color image forming apparatus capable of switching color modes, wherein the swing mechanism section is a solenoid provided between the swing unit and a stationary side of the apparatus. The solenoid is O in a direction in which the swing unit is rotated against the spring force of the spring.
It is characterized in that it is configured to be N.

According to a fourth aspect of the present invention, in the color image forming apparatus capable of switching between color modes, the swing mechanism is engaged with the driven gear on a central rotation shaft on which the swing unit is supported. It is characterized by comprising a restraint means for restraining or releasing the rotation.

According to a fifth aspect of the present invention, in the color image forming apparatus capable of switching between color modes, the oscillating mechanism is provided with a one-way clutch that meshes with a driven gear on a central rotating shaft that supports the oscillating unit. A clutch gear, which is formed one-way in a direction that does not restrict the rotation of the driven gear in a normal recording paper feed direction, and includes a drive mechanism supported by the swing unit. The driving source is formed so as to be rotatable in forward and reverse directions. A replaceable color image forming apparatus.

Further, in the color image forming apparatus capable of switching color modes according to a sixth aspect, the rocking unit includes:
Position detection means for detecting the amount of rotation of the oscillating unit to detect its rotational position and for holding the oscillating unit at that position is provided.

In the case of the full-color mode in which the swinging unit is not operated, the rotation of the drive source of the drive mechanism is one of a group of odd-numbered driven gears, for example, a group of BK driven gears and an even-numbered driven gears. Are transmitted to the M driven gear adjacent to the BK driven gear. These driven gears transmit rotation via idler gears to another driven gear in the group. Thereby, all the driven gears rotate simultaneously. Further, the diameter of the driven gear can be made larger than the axial distance between the adjacent photoconductors, and the value of the photoconductor diameter × π / the number of teeth of the driven gear becomes small, which reduces uneven rotation and prevents banding. .

On the other hand, when the swinging unit is operated, the drive gear and the BK / Y idle gear mesh with the driven gear of BK, but the driven gear of M and the drive gear adjacent to the driven gear of BK are connected to each other. The meshing is released, and the meshing between another odd-numbered Y driven gear and the BK · Y idle gear is released. Therefore, the rotation from the drive source is transmitted only to the driven gears of BK and not to the remaining driven gears. The above operation is easily performed by the rotation of the swing unit of the present invention, and the mode can be switched smoothly. In addition, since the swing mechanism of the swing unit does not use a mechanism such as a gear that easily causes backlash, occurrence of rotation unevenness is prevented.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a color image forming apparatus capable of switching color modes according to the present invention will be described below in detail with reference to the drawings. In this example, the driven gears of BK, M, Y, C,
The arrangement shown in FIG. 15 and the like is applied to the arrangement of the idle gear, the photoconductor and the like and the base of the transmission mechanism. That is, in this example, the drive transmission mechanism shown in FIG. 15 and the like is provided with a swing unit and a swing mechanism unit.

FIGS. 1 to 3 show one embodiment of a swing unit and the like according to the present invention. The drive unit side plate 3 of the oscillating unit 1 is provided with a central rotating shaft 30 of the photoconductor 23BK.
It is swingably supported by the BK. The drive unit side plate 3 is composed of a first drive unit side plate 3 ′ also serving as the drive unit side plate 33 shown in FIGS. 16 and 17 and a second drive unit side plate 3 ″ of the same shape arranged opposite to the first drive unit side plate 3 ′. The first drive unit side plate 3a and the drive mechanism 35 are connected to each other by a central rotation shaft 30BK of the photoconductor 23BK.
, And the idle gears 34BK and Y are supported by the rotating shaft 36.

A movable part 5 of a solenoid 2 which is one of the swinging mechanism parts is fixed to the drive unit side plate 3, and a main body 6 of the solenoid 2 is fixed to a stationary side 4, for example, a main body side plate 32 of the apparatus. Further, a spring 7 is provided between the drive unit side plate 3 and the immovable side 4, and urges the drive unit side plate 3 in a direction to rotate counterclockwise to the center rotation shaft 30BK. Further, the positioning member 8 is engaged and disengaged with the side surface of the drive unit side plate 3 at a position where it is engaged.

The movable portion 5 of the solenoid 2 engages with the main body 6 in a freely movable manner, and the drive unit side plate 3 is pulled by the spring 7 and abuts against the member 36, in the state shown in FIG.
The drive gear 40 moves from the driven gear 31BK and the driven gear 3 as shown in FIGS.
1M, and the idle gears 34BK and Y mesh with the driven gear 31BK and the driven gear 31Y. This state corresponds to the OFF state of the solenoid 2.

Next, when the solenoid 2 is turned on, the movable portion 5 is pulled toward the main body 6 side. Since the movable portion 5 is fixed to the swing unit side plate 3, the swing unit side plate 3 resists the spring force of the spring 7 and rotates clockwise about the central rotation shaft 30BK as shown in FIG. Therefore, the contact between the positioning member 8 and the swing unit side plate 3 is released. Since the motor 38, the drive gear 40, and the idle gears 34BK and Y of the drive mechanism 35 are supported by the swing unit side plate 3, the drive gear 40 is driven even when the swing unit side plate 3 rotates clockwise. The gear 31BK, the idle gear 34BK, Y and the driven gear 31BK mesh with each other.

However, as shown in FIG. 6, the drive gear 40 and the driven gear 31 are rotated by the rotation of the swing unit side plate 3.
The mesh with M is released and the idle gear 34BK · Y and driven gear 31Y are released. At this time, since the spring force of the spring 7 is weaker than the electric force for holding the solenoid 2 in the ON state, the swing unit side plate 3 is set at the position shown in FIG. In the state shown in FIG. 6, the driven gears 31M, 31M
Y and 31C do not rotate, only the driven gear 31BK rotates, and only monochrome mode image formation is performed. Here, when the solenoid is turned off, the movable portion 5 is extended by the spring force of the spring 7, and the swinging unit side plate 3 rotates counterclockwise until the swinging unit side plate 3 comes into contact with the positioning member 8, and FIG. Return to the state. Accordingly, the mode is switched to the full color mode, and all the driven gears 31BK, 31M, 31M are driven.
Y and 31C rotate, and full-color mode image formation is performed.

7 and 8 show another swing unit 1a. As the swing mechanism portion, a restraining means 2a for restraining the rotation of the driven gear 31BK instead of the solenoid 2 is provided, and specifically, the brake mechanism 9 is adopted. The brake mechanism 9 is fixed to the main body side plate 32 and is driven gear 31B.
Engage K. When the brake mechanism 9 operates, the driven gear 3
1BK is pinched and its rotation is restrained. In this example, a sensor 11 that detects the amount of rotation of the swing unit side plate 3 is used.
Is arranged on the stationary side, and the solenoid 10 is fixed to the main body side plate 32. Solenoid 10 is ON and OFF
The pin 10a is moved in and out by means of the pin 10a.
To fit. The state in which the pin 10a is fitted into the positioning hole 10b is the full color mode, and the pin 10a
Is fitted in the positioning hole 10c corresponds to the monochrome mode.

In order to switch from the full-color mode state to the monochrome mode in FIG. 7, first, the brake mechanism 9 is operated to restrict the rotation of the driven gear 31BK. Even in this state, the rotational force of the drive source motor 38 is transmitted through the drive gear to the driven gear 31.
Since the swing unit side plate 3 itself is transmitted to the BK,
As shown in FIG. When it comes into contact with the swing unit side plate 3 and the sensor 11 and it is detected that it has been turned by a predetermined amount of rotation, the solenoid 10 is turned off, the rotation of the motor 38 is stopped, and the pin 10a of the solenoid 10 is turned on as shown in FIG. Thus, the swing unit side plate 3 is fixed at the rotation position.

When the operation of the brake mechanism 9 is released, the rotation of the motor 38 is transmitted only to the driven gear 31BK, and the other driven gears 31M, 31Y and 31C do not rotate. On the other hand, when setting to the full color mode, the solenoid 10 is turned on, and the pin 10a is pulled out from the positioning hole 10b. The swing unit side plate 3 rotates clockwise by the spring force of the spring 7, and the pin 10a is fitted into the pin 10b. In this state, the driving gear 40 is driven by the driven gears 31BK, 3BK.
1M, and the idle gear 34BK · Y is driven gear 3
Since 1BK meshes with the driven gear 31Y, all the driven gears 31BK, 31M, 31Y, and 31C rotate at the same time, and the full-color mode is set.

FIG. 10 shows a detailed structure of the solenoid 10, which is composed of a solenoid body 10d, a spring 10e engaging with the pin 10a, etc., but the structure itself is a known technique.

FIGS. 11 and 12 show a further swinging unit 1.
b. This oscillating unit 1b employs a clutch gear 2b having a clutch as an oscillating mechanism in place of the brake mechanism 9, and specifically employs a clutch gear 2b having a one-way clutch 12. The clutch gear 2b is supported by the main body side plate 32 as shown in FIG. One-way clutch 1
In the full color mode, the reference numeral 2 rotates the gear 2b following the driven gear 31BK.
When the BK rotates in the reverse direction, it acts to restrict the rotation of the gear 2b.

In this embodiment, the motor 38 can be rotated forward and backward for mode switching. Also, the sensor 13
Solenoid 10 having pin 10a and positioning hole 10
Since b and 10c are the same as those described above, duplicate description will be omitted.

As shown in FIG.
1-way clutch 1
2 does not restrict the rotation of the clutch gear 2b, the driven gear 31BK rotates smoothly, and all the other driven gears 31M, 31M,
31Y and 31C rotate, and an image is formed in a full-color mode.

On the other hand, when switching to the monochrome mode, the motor 38 is rotated in the reverse direction as shown by the arrow B as shown in FIG. Along with this, the driven gear 31BK also tries to rotate, or the one-way clutch 12 of the clutch gear 2b acts to restrain the rotation of the driven gear 31BK. Therefore, the swing unit side plate 3 rotates clockwise, and the mesh between the drive gear 40 and the driven gear 31M and the idle gear 34
The engagement between BK · Y and the driven gear 31Y is released. The rotation amount of the swing unit side plate 3 is the same as that of the sensor 1 described above.
3 and the solenoid 1
0 acts, the pin 10a fits into the positioning hole 10b, and is fixed at a predetermined position. As described above, the monochrome mode image is formed.

To switch to the full-color mode, the swing unit side plate 3 is turned counterclockwise by the spring force of the spring 7 by turning off the solenoid 10 and pulling out the pin 10a from the positioning hole 10b to return to the original position. Return. Here, when the motor 38 rotates forward, all the driven gears 31BK, 31M, 31Y, and 31C rotate, and the one-way clutch 12 does not restrict the rotation of the driven gear 31BK, so that the one-way clutch 12 rotates smoothly, and the image in the full color mode is obtained. The formation takes place.

Although the above-mentioned several embodiments have been shown as the swinging mechanism, the present invention is not limited to these embodiments, and any swinging unit that swings in the full color mode and the monochrome mode can be used. Good.

[0041]

【The invention's effect】

1) According to the color image forming apparatus according to claim 1 of the present invention, which is capable of color mode switching, a rocking unit is provided, and when rocking the mode, the rocking unit is rotated to mesh the drive gear with the idle gear. Switching between the full-color mode and the monochrome mode can be easily performed by a simple method simply by changing the form. Since the swing unit is compactly assembled, the size and weight of the device can be reduced, and since the gear group and the like are not used as in the prior art, rotation unevenness does not occur due to switching.

2) According to the color image forming apparatus capable of switching the color mode according to the second aspect of the present invention, since the spring is used to return the swinging unit to the original position, the mode returns to the full color mode. Is performed reliably and smoothly.

3) According to the color image forming apparatus capable of switching the color mode according to the third aspect of the present invention, since the ON / OFF of the solenoid is used as the swing mechanism, a large-sized actuator is not required, and the apparatus is not required. Can be reduced in size and weight.

According to a fourth aspect of the present invention, as a color image forming apparatus capable of switching between color modes, a swing mechanism is connected to a center rotating shaft which swingably supports a swing unit. Restriction means for restricting rotation of the gear is used. As a result, the swing unit is reliably rotated, the switching between the full-color mode and the monochrome mode is smoothly performed without using a special actuator, and the apparatus is downsized because a complicated gear mechanism or the like is not used. The weight can be reduced.

5) According to the color image forming apparatus in which the color mode can be switched according to the fifth aspect of the present invention, since the one-way clutch is used as the swing mechanism portion, the swing unit can be reliably rotated. .

6) According to the color image forming apparatus capable of switching the color mode according to the sixth aspect of the present invention, the rotation position of the swing unit can be accurately determined by the position detection and holding means, so that the mode switching can be reliably performed. Performance and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a swing mechanism portion that swings a swing unit according to the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a side view of FIG.

FIG. 4 is a partial front view for explaining the operation of the swing mechanism shown in FIG. 1;

5 is a side view of FIG.

FIG. 6 is a partial front view showing a swinging state of the swinging unit shown in FIG. 4;

FIG. 7 is a partial front view showing another embodiment of the swing mechanism of the swing unit of the present invention.

FIG. 8 is a side view of FIG. 7.

FIG. 9 is a partial front view showing the swinging operation of the swinging mechanism shown in FIG. 7;

10 is an enlarged partial cross-sectional view showing the detailed structure of a solenoid for positioning the swing unit shown in FIG. 7 and the like.

FIG. 11 is a partial front view showing still another embodiment of the swing mechanism portion of the swing unit of the present invention.

FIG. 12 is a side view of FIG. 11;

FIG. 13 is a partial front view showing the swinging operation of the swinging mechanism shown in FIG. 11;

FIG. 14 is a configuration diagram showing an overall structure of a tandem type color image forming apparatus which forms an image in a four-color full color mode.

FIG. 15 is a front view showing one embodiment of the drive transmission mechanism section of the color image forming apparatus applied to the present invention.

FIG. 16 is a top view of FIG. 15;

FIG. 17 is a side view of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 swing unit 1 a swing unit 1 b swing unit 2 solenoid 2 a restraining means 2 b clutch gear 3 swing unit side plate 3 ′ first swing unit side plate 3 ″ second swing unit side plate 4 non-moving side 5 movable part 6 Main body 7 Spring 8 Positioning member 9 Brake mechanism 10 Solenoid 10a Pin 10b Positioning hole 10c Positioning hole 11 Sensor 12 One-way clutch 13 Sensor 14 Color image forming device 15BK Image forming unit (black) 15M Image forming unit (magenta) 15Y Image forming unit (Yellow) 15C Image forming unit (cyan) 16 Paper feed unit 17 Recording paper 18 Transfer belt 19 Polygon scanner 20 Deflection mirror 21 Laser scanner 22 Fixing unit 23BK Photoconductor (Black) 23M Photoconductor (Magenta) 23Y Photoconductor ( Yellow) 23C photoconductor (cyan) 24BK developing device (black) 24M developing device (magenta) 24Y developing device (yellow) 24C developing device (cyan) 25BK charging device (black) 25M charging device (magenta) 25Y charging device (yellow) 25C charging device (cyan) 26BK cleaning device (black) 26M cleaning device (magenta) 26Y cleaning device (yellow) 26C cleaning device (cyan) 27BK transfer device (black) 27M transfer device (magenta) 27Y transfer device (yellow) 27C transfer Device (cyan) 28 Scanner for reading 29 Image processing circuit 30BK Center rotation axis (black) 30M Center rotation axis (magenta) 30Y Center rotation axis (yellow) 30C Center rotation axis (cyan) 31 K driven gear (black) 31M driven gear (magenta) 31Y driven gear (yellow) 31C driven gear (cyan) 32 main body side plate 33 drive unit side plate 34BK / Y idle gear (black / yellow) 34M / C idle gear (magenta / cyan) ) 35 drive mechanism section 36 rotation shaft 37 rotation shaft 38 motor 39 drive shaft 40 drive gear 41 separation claw

Claims (6)

[Claims] 1. An image forming unit for four colors of black (BK), magenta (M), yellow (Y), and cyan (C) is arranged along a conveyance direction of a recording paper, and each image forming apparatus has The driven gear supported on the central rotation shaft of the photoconductor, the odd-numbered driven gear group (BK · Y), and the even-numbered driven gear group (M, C) are staggered in the axial direction. And the driven gears in each of the groups are connected via an idle gear, and one driven gear of the odd-numbered driven gear group and the even-numbered driven gear group adjacent thereto A color image forming apparatus including a drive gear that meshes with one of the driven gears and a drive mechanism section including the drive source, wherein the center rotation of the driven gear of one of the odd-numbered groups. The shaft is swingably supported and the drive A swing unit that holds a mechanism unit and supports the idle gear that meshes with the driven gear; and swings the swing unit to engage and disengage the drive mechanism unit and the idle gear with another driven gear. A color image forming apparatus capable of color mode switching, characterized in that a rocking mechanism section is provided. 2. The swing unit is rotated between the swing unit and the stationary side of the device in a direction approaching the other driven gear side so as to mesh the idle gear with the other driven gear. The color image forming apparatus according to claim 1, wherein a spring for causing the color mode is provided. 3. The swing mechanism section is a solenoid provided between the swing unit and a stationary side of the apparatus, and the solenoid resists the spring force of the spring and the swing unit. The color image forming apparatus according to claim 2, wherein the color image forming apparatus is configured to be turned on in a direction of rotating the. 4. The oscillating mechanism is provided with restraining means for engaging with the driven gear on a central rotation shaft on which the oscillating unit is supported to restrain or release its rotation. 2. A color image forming apparatus capable of color mode switching according to item 2. 5. The swing mechanism section comprises a clutch gear with a one-way clutch that meshes with a driven gear on a central rotating shaft that supports the swing unit, and the clutch gear operates in a normal recording paper feed direction. The drive source of the drive mechanism supported by the swing unit is formed so as to be rotatable in the forward and reverse directions. 3. The color image forming apparatus according to claim 2, wherein the color mode can be switched. 6. The swing unit is provided with position detection holding means for detecting the amount of rotation of the swing unit to detect its rotational position and for holding the swing unit at that position. 6. The color image forming apparatus according to claim 4, wherein the color mode can be switched.