JP2000029269A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To switch the drive of only one of a photoreceptor (13BK) only (monochrome mode: X) and the drive of four of the photoreceptors (full color mode: Y) by a simple means, as for a color image forming device arraying four of the photoreceptors carrying an image of different color in parallel. SOLUTION: This device is provided with a difference between positions in the shaft direction of gear wheels X (13BK and 13Y) of odd numbered photoreceptors (11BK and 11BY) shaft end from the end and the gear wheels Y (13M and 13C) of odd numbered photoreceptors (11M and 11C) from the shaft end, with gear wheels 14a and 14b respectively engaged with the gear wheels X and the gear wheels Y in common and with a drive gear wheel 22 engaged with the gear wheel 13BK and 13M. The gear wheels 14a and 22 are pivotally supported to a rocking blade 18a making a shaft concentric with the shaft 12 BK' of the photoreceptor 13BK as a rocking center to make it possible to rock integrally with the rocking blade and to make the engagement between gear wheels 14a and 13Y and the engagement between the gear wheels 22 and 13M possible to be switched with regard to an engaged state (Y) and the disengaged state (X).

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, and more particularly to a color image forming apparatus using a tandem system in which a photosensitive member driving system is improved.

[0002]

2. Description of the Related Art Mainly for the purpose of speeding up image output, image forming units of each color of black, magenta, cyan and yellow are arranged in a line, and recording is performed only by passing a recording sheet once along a recording sheet conveying path. There is a tandem type color image forming apparatus that forms a color image on paper. In such a tandem type color image forming apparatus, not only full color printing is always required, but also one of them is required.
In some cases, printing of only a color, for example, black, is required.

As described above, in a mono-color mode in which only one color is printed, for example, in a mode in which black and white printing is performed, 4
It is not necessary to use all the image forming units in the group, and it is desirable to stop the rotation of the photoconductor for image forming units that are not used. Since the rotation of the photoconductor deteriorates due to the wear of the cleaning blade that comes into contact with the photoconductor, stopping the rotation of the photoconductor when it is not necessary can prolong the life of the photoconductor, thereby reducing running costs. Because they are connected.

Japanese Patent Laid-Open Publication No. Hei 7-181773 discloses a drive selecting member which is connected to a shaft of a photoconductor driving motor, and which is idle when a rotation limiting force of a predetermined value or more is applied. A technique relating to switching of driving of a body drum is disclosed.

[0005]

In the above-mentioned prior art, a complicated gear train using a large number of gears is used for a power transmission system to the photosensitive member, and an electromagnetic clutch which is likely to be a complicated control system is used. The drive selection member switches power transmission to switch between the full color mode and the mono color mode.

Accordingly, the present invention provides a four-photoconductor drive system which is operated in response to switching between a full-color mode and a mono-color mode, and selectively connects and disconnects each of the photoconductors according to whether they are used or not. It is an object to simplify the configuration of the control means.

[0007]

The present invention has the following configuration to achieve the above object. (1). What is claimed is: 1. A color image forming apparatus in which four photoconductors carrying cyan, magenta, yellow, and black images are arranged in parallel along a recording paper conveyance direction. A driving force transmitting mechanism for transmitting rotation from the source to the photoreceptor shaft, wherein the odd and even photoreceptors counted from one end side in the arrangement direction are arranged on the photoreceptor shaft as the driving force transmitting mechanism. The plurality of photoreceptor shaft gears B arranged at positions shifted in the direction are connected to the odd-numbered photoreceptor shaft gears and the even-numbered photoreceptor shaft gears among the plurality of photoreceptor shaft gears B, respectively. Drive device A comprising two idle gears C and a drive gear D that can be commonly meshed with each of the adjacent odd-numbered and even-numbered photoreceptor shaft gears. A, the driving gears D and Serial two idler gears one idler gear C ₁ of the drive gear D close of the C is, the photosensitive member shaft gear of the photosensitive member for monocolor these drive gears D and idler gear C ₁ is engaged is retained photoreceptor Being held in an oscillating unit that can oscillate about an axis P as a rotation center,
The oscillating unit is in a state where the drive gear D and the idle gear C ₁ are meshed with a photoreceptor shaft gear other than the photoreceptor shaft gear on the photoreceptor shaft P, and the drive gear D and the idle gear C ₁ A switching mechanism for moving (rotating) and holding the photoconductor shaft P so as to be in two states of being engaged only with the photoconductor shaft gear; and a coaxially integrated with the drive gear D in the swinging unit. A rotatable gear E, a drive source fixed to the color image forming apparatus main body and having an output shaft arranged coaxially with the photoconductor shaft P, and an output shaft of the drive source meshing with the gear E And a gear F (claim 1).

(2). In the color image forming apparatus described in (1), the photoconductor axis P is a photoconductor axis located at one end or the other end in the arrangement direction.

(3). (1) In the color image forming apparatus described in (1) or (2), the switching mechanism moves the swing unit, which is swingably provided around the photoconductor axis P, in one direction of the swing direction. An urging means for urging, a stopper for stopping the swing by the urging means, and a solenoid for sucking or releasing the suction in a direction opposite to the direction of the urging by the urging means are constituted. ).

(4). What is claimed is: 1. A color image forming apparatus in which four photoconductors carrying cyan, magenta, yellow, and black images are arranged in parallel along a recording paper conveyance direction. A driving force transmitting mechanism for transmitting rotation from the source to the photoreceptor shaft, wherein the odd and even photoreceptors counted from one end side in the arrangement direction are arranged on the photoreceptor shaft as the driving force transmitting mechanism. The plurality of photoreceptor shaft gears B arranged at positions shifted in the direction are connected to the odd-numbered photoreceptor shaft gears and the even-numbered photoreceptor shaft gears among the plurality of photoreceptor shaft gears B, respectively. Drive device A comprising two idle gears C and a drive gear D that can be commonly meshed with each of the adjacent odd-numbered and even-numbered photoreceptor shaft gears. A, the driving gears D and Serial two idler gears one idler gear C ₁ of the drive gear D close of the C is, the photosensitive member shaft gear of the photosensitive member for monocolor these drive gears D and idler gear C ₁ is engaged is retained photoreceptor The driving unit D and the idle gear C ₁ are held in a swing unit that can swing about the axis P as a rotation center. body axis state is also meshed with the gear and the driving gear D, moving as the idler gear C ₁ can take two states of a state, which meshes only the photoconductor shaft gear of the photosensitive body shaft P (rotation), is retained A switching mechanism, a gear E rotatable coaxially and integrally with the drive gear D in the swinging unit, and a gear rotatably held on the photoconductor shaft P with respect to the photoconductor shaft P; The rotation of the drive source to the gear F 'meshing with E A transmission mechanism for transmitting is provided (claim 1).

(5). (4) In the color image forming apparatus described in (4), the photoconductor axis P is an axis located at one end or the other end in the arrangement direction.

(6). In the color image forming apparatus described in (4) or (5), the switching mechanism moves the swing unit, which is swingably provided around the photoconductor axis P, in a position direction in the swing direction. Biasing means for biasing;
A stopper for stopping the swing by the urging means and a solenoid for sucking or canceling the suction in the opposite direction of the urging by the urging means are provided (claim 6).

(7). (1), (2), (3),
In the color image forming apparatus described in (4), (5) or (6), the monocolor photoconductor is a photoconductor that carries a black image.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [1] Example corresponding to claims 1, 2, 3, and 7 a. Configuration of Color Image Forming Apparatus FIG. 1 is a schematic diagram of a tandem type color image forming apparatus as an example of a color image forming apparatus suitable for implementing the present invention. Referring to FIG.
04, the conveyance belt 110, and the fixing unit 103, along the conveyance direction of the recording paper along the upper surface of the conveyance belt 110 along the conveyance direction of the recording paper indicated by the arrow 120 in the conveyance direction of the recording paper. Four image forming units of magenta, yellow, and cyan are arranged.

Each of these image forming sections has the same mechanical configuration except for the type of exposure light used and the developer, and has a drum-shaped photosensitive member 106 and a charging device 107 disposed around the photosensitive member 106. , A developing device 108, a cleaning device 109, and the like as main members.

Constituent members of the image forming section for black are illustrated by adding BK to the reference numerals of the respective constituent members. Hereinafter, similarly, constituent members of the magenta, yellow, and cyan image forming sections will be described. For the constituent members to be described, the reference numerals of the above-described constituent members are denoted by the reference numerals of M, Y, and C. Each time the recording paper conveyed in the direction of the arrow 120 together with the conveyance belt 110 passes through each image forming unit, different colors are sequentially transferred, and finally a color image is obtained by superimposing four colors.

As described above, each image forming section has a drum-shaped photosensitive member (106BK,
106M, 106Y, 106C) and charging devices (107BK, 107BK,
107M, 107Y, 107C) and a developing device (108B
K, 108M, 108Y, 108C) and the like. An exposure device 105 is provided above each of these image forming apparatuses, and a color scanner 100 for scanning a document is further provided thereon. Color scanner 10
The document image information scanned at 0 is processed as color image information by the image processing circuit 101 and output to the exposure device 105.

The exposure device 105 has a configuration in which a laser beam from a laser light source is reflected by a polygon scanner 111. Further, the optical path is bent by a number of deflecting mirrors, and the photosensitive members (106BK, 106M, 106Y, 106
It comprises a laser scanner for exposing the surface of C). In this laser scanner, the photoconductor (106BK,
106M, 106Y, and 106C), main scanning is performed with exposure light modulated by an image signal in the axial direction (a direction orthogonal to the recording paper conveyance direction), and the photosensitive member is rotated in a direction orthogonal to the axial direction of the photosensitive member. The sub-scan is performed.

In addition, without providing the color scanner 100,
The image forming apparatus may be configured in combination with a unit for inputting image information to the image processing circuit 101.

In forming an image, the photosensitive member (106B
K, 106M, 106Y, 106C) are charging devices.
(107BK, 107M, 107Y, 107C), and is exposed by the exposure device 105 in a pattern corresponding to an image to be output.
06M, 106Y, 106C).

These electrostatic latent images are stored in a developing device (108B
K, 108M, 108Y, 108C) to form toner images on the surfaces of the photoconductors (106BK, 106M, 106Y, 106C). On the other hand, the recording paper sent from the paper feeding unit 102 according to the sequence
The image forming apparatus waits at the registration unit 104, is sent out from the registration unit 104 at a certain timing, and is electrostatically attracted to the transfer belt 110.

The recording paper on the transfer belt 110 that moves together with the transfer belt 110 is a photoconductor (106BK, 106BK).
M, 106Y, 106C) at the transfer position
Upon receiving the transfer of the toner image, that is, a black toner image, a magenta toner image, a yellow toner image, and a cyan toner image are sequentially formed as a superimposed transfer image.

The recording paper having undergone a series of transfer is separated from the transfer belt 110 by a separation claw 112 disposed at the rear end of the conveyor belt 110, and the toner image is passed through the fixing roller 103R of the fixing unit 103. Is fixed and conveyed to a paper discharge unit (not shown). Further, the toner remaining on the surface of the photoconductor (106BK, 106M, 106Y, 106C) after the transfer is removed by a cleaning device (109BK,
109M, 109Y, 109C).

In the above process, the alignment of the toner images of each color at the time of transfer includes the timing at which the recording paper is conveyed from the registration unit 104 to the transfer position of each color by the transfer belt 110, and the timing of the transfer of each photoconductor (106BK, 106M, 10M).
6Y, 106C) is set by setting the exposure start time so that the timing of moving the image on the transfer position coincides with each color.

B. Configuration of Photoconductor Drive Device A A specific example of the photoconductor drive device A, which is a configuration used in all claims of the present invention, will be described with reference to FIGS. In these figures, the components common to those of the color image forming apparatus in FIG. 1 described above are denoted by the same reference numerals.

Photoconductors 11BK, 11M, 11Y, 11C
And photoreceptor shafts holding these photoreceptors, respectively, are denoted by reference numerals 12BK and 12BK, respectively.
Shown as 12M, 12Y, 12C. These photoconductor shafts 12
BK, 12M, 12Y, and 12C are rotatably supported by a main body side plate 16 of an immovable image forming apparatus via bearings 17, respectively.

A swing unit side plate 19 is provided in parallel with the main body side plate 16 at an interval. These main body side plates 16
Between the photoreceptor shaft 1 and the swing unit side plate 19.
2BK, 12M, 12Y, and 12C have photoconductor shaft gears 13BK, 13M, 13
Y and 13C are fixed. Here, the fixing positions of these photoreceptor shaft gears are not on the same line but are shifted.

This state of displacement is caused by the photoconductors 11BK, 11BK
One (odd) photoconductor shaft gear 13BK and the third (odd) photoconductor shaft gear 13BK counted from one end side in the arrangement direction of M, 11Y, 11C, for example, from the upstream end in the recording paper transport direction in this example. Is located on substantially the same plane as the photoreceptor shaft gear 13Y,
The second (even-numbered) photoreceptor shaft gear 13M and the fourth (even-numbered) photoreceptor shaft gear 13C are located at positions shifted from the plane on which the photoreceptor shaft gears 13BK, 13Y are located to the photoreceptor side. positioned.

That is, among the plurality of photoconductor shaft gears B, odd-numbered photoconductor shaft gears 13BK and 13Y in the arrangement direction,
The even-numbered photoconductor shaft gears 13M and 13C are arranged at positions shifted from each other in the axial direction on the photoconductor shaft.

Further, these odd-numbered photosensitive member shaft gears 1
An idle gear 14a is supported by a short shaft 15a so as to mesh with the 3BK and the photoreceptor shaft gear 13Y in common. The short shaft 15a is fixed to the swing unit side plate 19. Similarly, the even-numbered photoconductor shaft gear 13M and the photoconductor shaft gear 1
An idle gear 14b is supported by the short shaft 15b so as to mesh with the 3C in common. The short axis 15b is fixed to the main body side plate 17 of the image forming apparatus. These two idler gears 14a, 14b are collectively referred to by the symbol C.

First photosensitive member shaft gear 1 in adjacent relationship
A drive gear 22 as a drive gear D is provided so as to mesh with the 3BK and the third photoreceptor shaft gear 13Y in common. The drive gear 22 is fixed to a shaft of a motor 21 and is driven to rotate by the motor 21. The drive gear D may be a combination of the third photoreceptor shaft gear 13Y and the fourth photoreceptor shaft gear 13C in addition to the above-described example. This is one configuration example of the photoconductor driving device A.

C. Configuration of Swing Unit In such a configuration, as shown in FIG. 2, the rotation of the motor 21 is controlled by the drive gear 22 (drive gear D) → photoconductor shaft gear 13BK (photoconductor shaft gear B) → play gear 14a ( The idle gear C) is transmitted through the path of the photoconductor shaft gear 13Y (photoconductor shaft gear B) to rotate the photoconductor 11BK and the photoconductor 11Y, and the drive gear 22 (drive gear D) → photoconductor shaft gear B ( The photoreceptor shaft gear 13M) → the idle gear 14b (the idle gear C) → the photoreceptor shaft gear C (the photoreceptor shaft gear 13C) is transmitted to rotate the photoreceptor 12M and the photoreceptor 11C. That is, the four photoconductors 11BK, 11M, 11C,
A full-color mode in which a toner image is formed on each photoconductor by rotating all of 11Y and transferred to recording paper can be executed.

In order to execute the mono-color mode in which a toner image is formed only on the photoconductor 11BK and transferred to recording paper from the full-color mode, the configuration shown in FIGS. As shown, the motor 21, the drive gear 22, and the idle gear 14a are integrally rotated in a clockwise direction about the photosensitive shaft 12BK serving as the photosensitive shaft P. That is, the swing unit side plate 19 is rotated clockwise around the photoconductor shaft 12BK. As a result, the idle gear 14a and the drive gear 22 are also rotated about the photosensitive shaft 12BK together with the swing unit side plate 19, and the engagement of the idle gear 14a with the photosensitive shaft gear 13Y is released. Figure 5 shows this situation.
The drive gear 22 rotates only the photoreceptor shaft gear 13BK, so that a monochrome image based on a black image is executed.

In executing the mono-color mode, the shaking means, which is a specific means for rotating the motor 21, the driving gear 22, and the idle gear 14a in a clockwise direction about the photosensitive body shaft 12BK, integrally. Fig. 5
This will be described with reference to FIGS.

The structure of the photosensitive member drive unit A in FIGS. 5 to 8 is common to the photosensitive member drive unit A in FIGS. 2 to 4 in the main part, and the common parts are denoted by the same reference numerals. The description will be omitted, and different points will be described.

As shown in FIGS. 7 and 8, the photoconductor shaft gear 13BK is fixed to the photoconductor shaft 12BK 'corresponding to the photoconductor shaft 12BK in the above-described example, but the photoconductor shaft is not changed. The difference is that two swing unit side plates 18a and 18b are pivotally attached to the photoreceptor shaft 12BK 'via bearings so as to sandwich the photoreceptor shaft gear 13BK on 12BK'. Therefore, a symbol “′” is assigned to 12BK. Further, the swing unit side plates 18a and 18b
The interval is maintained by 8c. Thus, the swing unit side plates 18a and 18b are integrally formed with the photosensitive member shaft 12B.
It can rotate around K '.

A short axis 15a 'extending inward is fixed to the swing unit side plate 18b.
A play gear 14a is supported at a '. Drive gear 22
Are fixed to shafts 41 which are respectively supported by the drive unit side plates 18a and 18b. The shaft 41 protrudes outside the swing unit side plate 18a, and a gear 42 (gear E) as the gear E is fixed to the shaft end.

Reference numeral 44 denotes a side plate fixed to the main body of the image forming apparatus. The output shaft of the motor 21 is the photosensitive shaft 2
The side plate 4 is made coaxial with the extension of the 1BK 'axis.
4 is fixed. A gear 43 as a gear F is fixed on the motor output shaft.
The upper gear 42 meshes with each other.

As described above, the drive gear 22 (drive gear D)
And the idler gear 14a (idle gear C ₁ ) of the two idler gears 14a and 14b (idle gear C) closer to the drive gear 22.
However, the oscillating unit that can oscillate about the photosensitive member shaft 12BK ′ of the photosensitive member for a mono-color in which the driving gear 22 (the driving gear D) and the idle gear 14a (the idle gear C ₁ ) mesh with each other is rotated. It comprises unit side plates 18a, 18b, and a drive gear 22, a gear 42, an idle gear 14a, and the like provided via the drive unit side plates 18a, 18b.

D. Switching Mechanism of Swing Unit The switching mechanism of the swing unit is shown in FIG.
c, one end is hung, and the other end is hung on the main body side of the image forming apparatus.
A spring 32 which acts as an urging means for urging the photoreceptor shaft 12BK about its axis, a stopper 33 for stopping the rocking of the rocking unit side plates 18a and 18b by the spring 32, and a spring 32 The solenoid unit 31 is capable of pulling the swing unit side plates 18a and 18b in the opposite directions against the force of (1) and rotating them in the opposite direction.

E. Operation In such a device, as shown in FIG. 6, when the solenoid 31 is in the non-excited state (OFF), the swing unit side plates 18a and 18b
In this state, the driving gear 22 meshes with the photoreceptor shaft gear 13BK and the photoreceptor shaft gear 13M, and the idle gear 14a connects the photoreceptor shaft gear 13BK, Meshes with 13Y.

Therefore, the rotation of the motor 21 is controlled by the gear 43 →
The transmission is performed in the order of the gear 42 and the gear 22, and as a result, all of the photoconductors 11BK, 11M, 11C, and 11Y are rotationally driven. That is, the full color mode is executed.

On the other hand, when the solenoid 31 is switched from this state to the excited state (ON), the swing unit side plate 18
a, 18b are photosensitive member shafts 1 concentric with the output shaft of the motor 21;
As shown in FIG. 9, the idle gear 14a and the drive gear 22 are also rotated about the photoreceptor shaft 12BK together with the swing unit side plates 18a and 18b. While the meshing between the coaxial gear 42 and the gear 43 fixed to the motor output shaft is maintained, the meshing of the drive gear 22 with the photoreceptor shaft gear 13M is released while the meshing with the photoreceptor shaft gear 13BK is maintained. The engagement of the idle gear 14a with the photoreceptor shaft gear 13Y is released. As a result, the drive gear 22 rotates only the photoreceptor shaft gear 13BK, and a monochrome image based on a black image is executed.

As described above, in the configuration in which the swinging unit and the switching mechanism are provided, only by swinging the swinging unit,
Since the switching between the full-color mode and the mono-color mode can be performed, the configuration for switching between these modes can be simplified.

In this example, the photosensitive member axis P is used as the photosensitive member axis 1
Although the case where 2BK 'is selected has been described, the photosensitive unit shaft 12C located at the other end in the arrangement direction is selected as the photosensitive unit shaft P, and the swing unit is connected to the photosensitive unit shaft 12P.
It is also possible to adopt a configuration that swings around C. In that case, the color executed in the mono color mode is cyan. However, since these colors can be freely allocated, it is possible to select the color in the mono color mode to any of black, magenta, yellow, and cyan.

In this embodiment, since the switching mechanism uses the spring 32, the stopper 33, the solenoid 31, and the like as urging means, the mode can be easily switched by on / off control of the solenoid. .

In this embodiment, the photosensitive member in which the mono-color mode is executed is the black photosensitive member 11BK. Therefore, it is possible to selectively obtain a black image generally used as a mono-color image and a full-color image. Can be.

Further, since the gear 42 is provided so that the relatively heavy motor 21 is not mounted on the swing unit, the size of the swing unit side plates 18a and 18b, the solenoid 31, and the like can be reduced. As a result, the swing unit itself can be downsized. Further, since the motor 21 is fixed to the main body, vibration can be reduced.

[2] Example corresponding to claims 4, 5, 6, and 7 a. Configuration of Color Image Forming Apparatus Since the configuration is the same as that of the tandem type color image forming apparatus described in the above [1], description thereof is omitted.

B. Configuration of Photoconductor Drive Device A The basic configuration is the same as the configuration described with reference to FIGS.

C. Configuration of Swinging Unit The basic configuration is the same as the configuration described with reference to FIGS. That is, FIGS. 10, 11,
As shown in FIG. 12, the drive gear 22 (drive gear D)
And the idler gear 14a (idle gear C ₁ ) of the two idler gears 14a and 14b (idle gear C) closer to the drive gear 22.
However, the oscillating unit that can oscillate about the photosensitive member shaft 12BK ′ of the photosensitive member for a mono-color in which the driving gear 22 (the driving gear D) and the idle gear 14a (the idle gear C ₁ ) mesh with each other is rotated. It comprises unit side plates 18a, 18b, and a drive gear 22, a gear 42, an idle gear 14a, and the like provided via the drive unit side plates 18a, 18b.

As shown in FIGS. 10, 11 and 12, the photoconductor shaft 12B corresponds to the photoconductor shaft 12BK 'in the above-described example.
The point that the photoreceptor shaft gear 13BK is fixed to K ″ is the same, but it protrudes outside the swinging unit side plate 18b, and the protruding shaft portion has the gear 45 as the gear F ′ and the gear 45 A pulley 46 configured integrally with
The difference is that they are rotatably supported via bearings.

The gear 45 is provided with a transmission mechanism from the motor 21. The transmission mechanism includes a pulley 46, a pulley 48 provided on the output shaft of the motor 21, a belt 47 around which the pulley 46 and the pulley 48 are wound. Here, it is preferable to use a toothed belt as the belt 47 to prevent slippage. Therefore, the pulley 46,
The pulley 48 also has a toothed shape.

D. Switching Mechanism of Swing Unit The basic structure is the same as the structure described in the item [d] of [1], and the swing unit side plates 18a and 18b are
A spring 32 as an urging means for urging in the direction of rotation about BK ", and a stopper 3 for stopping the rocking of the rocking unit side plates 18a, 18b by the spring 32.
3 and the swing unit side plates 18a,
The solenoid 18 includes a solenoid 31 which can be pulled in the opposite direction and turned in the opposite direction.

E. Operation In such an apparatus, as shown in FIG. 10, when the solenoid 31 is in a non-excited state (OFF), the swing unit side plates 18a and 18b are rotated by the force of the spring 32 until they contact the stopper 33. In this state, the drive gear 22 meshes with the photoreceptor shaft gear 13BK and the photoreceptor shaft gear 13M, and the idle gear 14a
Mesh with the photoreceptor shaft gears 13BK, 13Y.

Therefore, the rotation of the motor 21 is controlled by the pulley 48
→ Belt 47 → Pulley 46 → Gear 45 → Gear 42 → Gear 22 are transmitted in this order, and as a result, the photoconductor 11BK,
All of 11M, 11C and 11Y are rotationally driven. That is, the full color mode is executed.

On the other hand, when the solenoid 31 is switched from this state to the excited state (ON), the swing unit side plate 18 is turned on.
a, 18b are photosensitive member shafts 1 concentric with the output shaft of the motor 21;
As shown in FIG. 12, the idle gear 14a and the drive gear 22 are also pulled together with the swing unit side plates 18a and 18b by the photosensitive member shaft 12B.
The gear 42 is rotated about K ″, the gear 42 coaxial with the drive gear 22 remains engaged with the gear 45, and the drive gear 22 maintains the engagement with the photoreceptor shaft gear 13 </ b> BK, The engagement with the gear 13M is released, and the engagement of the play gear 14a with the photoreceptor shaft gear 13Y is released, whereby the drive gear 22 rotates only the photoreceptor shaft gear 13BK, and a mono-color black image is formed. Is executed.

As described above, in the configuration in which the transmission mechanism including the pulley 46, the pulley 48 provided on the output shaft of the motor 21, and the belt 47 around which the pulley 46 and the pulley 48 are wound, the position of the drive motor 21 is determined. Is not limited to being coaxial with the photoreceptor shaft 12BK 'as in the above-described example, and flexibility in arrangement can be obtained. Further, since the gear 45 is disposed on the photoreceptor shaft 12BK "and the position relative to the shaft 41 is determined on the swing unit side plates 18a and 18b, the distance between the shafts can be easily managed. .

In addition, similar advantages can be obtained from the components common to the configuration described in the above [1]. That is, in the configuration in which the swinging unit and the switching mechanism are provided, switching between the full-color mode and the monocolor mode can be performed only by swinging the swinging unit. Can be achieved.

Further, as the photosensitive member shaft P, the photosensitive member shaft 12B
K ”was selected, but without doing so,
As the photoconductor shaft P, a photoconductor shaft 12C located at the other end in the arrangement direction may be selected, and the swing unit may be configured to swing around the photoconductor shaft 12C. In that case, the color executed in the mono color mode is cyan. Of course, these colors can be sorted freely, so in the end the color in the mono color mode is black,
Any of the colors magenta, yellow, and cyan can be selected.

Since the switching mechanism uses the spring 32, the stopper 33, the solenoid 31, and the like as urging means, the mode can be easily switched by controlling the on / off of the solenoid.

Further, since the photosensitive member in which the mono color mode is executed is the black photosensitive member 11BK, a black image generally used as a mono color and a full color image can be selectively obtained. .

Further, since the gear unit 42 is provided so that the motor 21 having a relatively heavy weight is not mounted on the swing unit, the size of the swing unit side plates 18a and 18b and the solenoid 31 can be reduced. As a result, the swing unit itself can be downsized.

In each of the above examples, in the mono-color mode, means (not shown) is provided so that the transfer belt 110 is appropriately separated from the photoreceptor whose driving force has been cut off so as not to damage the image. Shall be.

[0065]

According to the first aspect of the present invention,
An output shaft of a drive source is arranged coaxially with a photosensitive member axis, which is a swing center of a swing unit that holds a drive gear and an idle gear, and the drive source is fixed to and held by the main body, thereby allowing the swinging unit to swing. There is no need to hold a drive source in the unit, and there are four photoconductor drive systems that are performed in response to switching between the full-color mode and the monocolor mode, and according to the selective use and non-use of each photoconductor. The structure of the disconnection / connection control means can be simplified and downsized.

According to the second aspect of the present invention, the rotation of the other photosensitive member shaft can be cut off while leaving the photosensitive member shaft located at one end or the other end in the arrangement direction. The degree of freedom in selecting a photoconductor that realizes color is increased. For the same reason, the degree of freedom in selection on the layout also increases.

According to the third aspect of the present invention, the switching between the full-color mode and the mono-color mode can be performed by the control signal to the solenoid, so that the switching operation can be easily performed by the switch operation.
The configuration of the switching means is also simple.

According to the fourth aspect of the present invention, there is provided the first aspect.
In the invention described in (1), an output shaft of a drive source is arranged coaxially with a photosensitive member axis which is a swing center of a swing unit for holding a drive gear and an idle gear, and the drive source is fixed to the main body. By holding the drive unit, there is no need to hold a drive source in the swinging unit, and the four photoconductor drive systems performed in response to switching between the full color mode and the mono color mode, and the selective selection of each photoconductor It is possible to simplify the configuration of the disconnection / connection control means depending on the use or non-use, and to reduce the size. Further, by providing the transmission mechanism, it is not necessary to hold the driving source in the swing unit, and the swing unit and its movement (rotation) and holding mechanism can be downsized. Further, the degree of freedom in the arrangement of the driving source can be increased, and the axes in the same swinging unit are mutually connected.
1BK ″) can be improved in the accuracy of the distance between axes.

According to the fifth aspect of the present invention, the rotation of the other photosensitive member shaft can be cut off while leaving the photosensitive member shaft located at one end or the other end in the arrangement direction. The degree of freedom in selecting a photoconductor to be realized is increased.
For the same reason, the degree of freedom in selection on the layout also increases.

According to the sixth aspect of the present invention, the switching between the full color mode and the mono color mode can be performed by the control signal to the solenoid, so that the switching operation can be easily performed by the switch operation, and the structure of the switching means is also improved. It is simple.

According to the seventh aspect of the present invention, the photosensitive member in which the monocolor mode is executed is a photosensitive member on which a black toner image is formed. A full-color image can be selectively obtained, and the structure of a mechanism in such an image forming apparatus can be simplified.

[Brief description of the drawings]

FIG. 1 is a front view illustrating an overall configuration of an image forming apparatus suitable for carrying out the present invention.

FIG. 2 is a front view illustrating details of a photoconductor driving system in a full-color mode.

FIG. 3 is a plan view of the photoconductor driving system shown in FIG. 2;

FIG. 4 is a right side view of the photoconductor drive system shown in FIG. 2;

FIG. 5 is a front view illustrating details of the photoconductor drive system after switching to the monocolor mode in the photoconductor drive system illustrated in FIG. 2;

FIG. 6 is an example of the present invention in a full color mode;
FIG. 3 is a front view illustrating details of a photoconductor driving system.

7 is a plan view of the photoconductor drive system shown in FIG.

FIG. 8 is a right side view of the photoconductor driving system shown in FIG.

FIG. 9 is a front view illustrating details of the photoconductor drive system after switching to the monocolor mode in the photoconductor drive system illustrated in FIG. 6;

FIG. 10 is a front view illustrating another example of the present invention and illustrating the details of a photoconductor driving system in a full-color mode.

11 is a plan view of the photoconductor driving system shown in FIG.

FIG. 12 is a front view illustrating details of the photoconductor drive system after switching to the monocolor mode in the photoconductor drive system illustrated in FIG. 10;

[Explanation of symbols]

12BK, 12BK ′, 12BK ″ Photoconductor shaft 12M, 12Y, 12C (as photoconductor shaft P) Photoconductor shaft 13BK, 13M, 13Y, 13C Photoconductor shaft gear (as photoconductor gear B) 14a (play gear C) and as C ₁₎ idle gear 14b (serving as idler gears C) idler gears 21 (serving as a drive source) motor 22 (serving as a drive gear D) as a driving gear 31 (urging means) solenoid 32 (biasing means Spring 33 (as biasing means) Stopper 41 (as gear E) Gear 42 (as gear E) Gears 46, 48 Pulley (as transmission mechanism) 47 Belt (as transmission mechanism)

Claims (7)

[Claims] 1. A color image forming apparatus in which four photoconductors carrying cyan, magenta, yellow, and black images are arranged in parallel along a recording paper conveyance direction. And a driving force transmitting mechanism for transmitting rotation from the driving source to the photoreceptor shaft, wherein the driving force transmitting mechanism includes an odd-numbered and an even-numbered photoreceptor counted from one end in the arrangement direction. A plurality of photoreceptor shaft gears B disposed at positions axially displaced from each other on the shaft, and among the plurality of photoreceptor shaft gears B, odd-numbered photoreceptor shaft gears and even-numbered photoreceptor shaft gears , Respectively, and a photoconductor drive device A including a drive gear D that can mesh with one of the adjacent odd-numbered and even-numbered photoconductor shaft gears in common, and In this photoconductor driving device A, the drive One idle gear C ₁ of the drive gear D close of the gear D and the two idler gears C, and these drive gear D and idler gears C ₁
Are held in an oscillating unit that can oscillate about a photoreceptor shaft P on which a photoreceptor shaft gear of a monocolor photoreceptor is held, and the oscillating unit is connected to the driving gear D and the driving gear D. The state in which the idle gear C ₁ is meshed with a photoreceptor shaft gear other than the photoreceptor shaft gear on the photoreceptor shaft P, and the drive gear D and the idle gear C ₁ are only on the photoreceptor shaft gear of the photoreceptor shaft P A switching mechanism for moving (rotating) and holding so as to take two states of meshing state, a gear E that can rotate integrally with the driving gear D in the swinging unit, and a color image forming apparatus. A drive source fixed to the apparatus main body and having an output shaft arranged coaxially with the photoconductor shaft P; and a gear F on the output shaft of the drive source meshing with the gear E
And a color image forming apparatus. 2. A color image forming apparatus according to claim 1, wherein said photosensitive member shaft P is a photosensitive member shaft located at one end or the other end in said arrangement direction. 3. The color image forming apparatus according to claim 1, wherein the switching mechanism is configured to move the swing unit provided so as to be swingable about the photosensitive member axis P in the swing direction. A biasing means for biasing in one direction, a stopper for stopping swinging by the biasing means, and a solenoid for sucking or releasing suction in a direction opposite to the direction of biasing by the biasing means. A color image forming apparatus. 4. A color image forming apparatus in which four photoconductors carrying cyan, magenta, yellow, and black images are arranged in parallel along the direction in which a recording paper is conveyed. And a driving force transmitting mechanism for transmitting rotation from the driving source to the photoreceptor shaft. A plurality of photoreceptor shaft gears B disposed at positions axially displaced from each other on the shaft, and among the plurality of photoreceptor shaft gears B, odd-numbered photoreceptor shaft gears and even-numbered photoreceptor shaft gears , Respectively, and a photoconductor drive device A including a drive gear D that can mesh with one of the adjacent odd-numbered and even-numbered photoconductor shaft gears in common, and In this photoconductor driving device A, the drive One idle gear C ₁ of the drive gear D close of the gear D and the two idler gears C, and these drive gear D and idler gears C ₁
Are held in an oscillating unit that can oscillate about a photoreceptor shaft P on which a photoreceptor shaft gear of a monocolor photoreceptor is held, and the oscillating unit is connected to the driving gear D and the driving gear D. idler gear C ₁ is the photoconductor sensitivity optical body axis P
A possible state and the driving gear D which also meshes with the photoreceptor shaft gear other than photoconductor shaft gear above, state that the idler gear C ₁ is engaged only in photoreceptor shaft gear of the photosensitive member shaft P, and two states Mechanism for moving (rotating) and holding as described above, a gear E which can be integrally and coaxially rotated with the drive gear D in the swinging unit, and a photoreceptor shaft P on the photoreceptor shaft P
A transmission mechanism for transmitting the rotation of the driving source to a gear F ′ that is rotatably held with respect to the gear E and meshes with the gear E. 5. The color image forming apparatus according to claim 4, wherein said photosensitive member axis P is an axis located at one end or the other end in said arrangement direction. 6. The color image forming apparatus according to claim 4, wherein the switching mechanism is configured to move the swing unit provided so as to be swingable about the photoreceptor axis P in the swing direction. A biasing means for biasing in the position direction, a stopper for stopping swinging by the biasing means, and a solenoid for sucking or releasing suction in a direction opposite to the direction of biasing by the biasing means. Characteristic color image forming apparatus. 7. A color image forming apparatus according to claim 1, wherein said monocolor photoconductor is a photoconductor carrying a black image. Image forming device.