JP2000250315A - Driving device, developing device provided with the same, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image with high definition without lateral stripe irregularity etc., by preventing the fluctuation of the rotating speed of rotary driving force transmitted to the developing device from a driving source without making a device large and increasing the cost. SOLUTION: When a Y clutch 110y, a C clutch 110c, and a BK clutch 110BK transmit the rotary driving force from a driving motor to the one developing device selected from a Y developing device 4y, a C developing device 4c, an M developing device 4m, and a BK developing device 4BK while a fly wheel 203 imparts inertia to the rotary driving force between the driving source and the Y clutch 110y, C clutch 110c, and the BK clutch 110BK; the rotary driving force is transmitted in a state where the driving motor is temporarily and repeatedly connected to the two developing devices in the case of switching to the developing device selected next and the switching is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for selectively transmitting a rotational driving force from one driving source to a plurality of developing devices, a developing device having the driving device, and an image forming apparatus. is there.

[0002]

2. Description of the Related Art Conventionally, in such an image forming apparatus,
A plurality of developing devices corresponding to each of the separated colors of the image information are selectively brought closer to the latent image carrier for holding the latent image according to each of the separated colors by operation of an eccentric cam or the like. 2. Description of the Related Art An image forming apparatus that develops a latent image on the latent image and forms an image of a toner as a developer, which is a powder based on a resin and a pigment, on a latent image carrier is known. I have.

In such an image forming apparatus, when the rotational driving force is transmitted to one selected developing device, the rotational driving force is applied to the two developing devices when switching to the next selected developing device. A drive device is provided for transmitting and switching in a state where the device is temporarily redundantly connected to the device.

[0004] Such a driving device will be described with reference to Figs. FIG. 5 is a development view of a conventional driving device, and FIG. 6 is a timing chart showing the driving timing of each developing device in the driving device of FIG.

First, the configuration of such a driving device will be described.

As shown in FIG. 5, such a driving device is a driving device for driving four developing devices, ie, a Y developing device 4y, a C developing device 4c, an M developing device 4m, and a BK developing device 4BK, respectively. A driving motor (not shown) as a driving source, and a Y developing unit 4y, a C developing unit 4c, an M developing unit 4m, B
The rotational driving force from the drive motor connected to the K developing device 4BK is applied to the Y developing device 4y, the C developing device 4c, and M, respectively.
Developing device 4m, BK developing device 4BK
It has an M clutch 110m and a BK clutch 110BK.

In such a driving device, first, the rotational driving force from the driving motor is applied to the timing belt 101.
Thus, it is transmitted to the input pulley 102, the input shaft 103, and the distribution gear 104. The distribution gear 104 meshes with the M clutch gear 109m, the C clutch gear 109c, and the idler gears 105, 107. The rotational driving force from the idler gear 105 is transmitted to the BK clutch gear 109BK via the idler gear 106, and the idler gear The rotational driving force from the motor 107 is
To the Y clutch gear 109y.

Here, when the M clutch 110m is turned on (transmission state), the output shaft 111m and the output gear 112
m, the M developing device 4m is driven via the sleeve gear 113m.

Similarly, a Y developing device 4y, a C developing device 4c,
As for the K developing device 4BK, when the Y clutch 110y, the C clutch 110c, and the BK clutch 110BK are turned on, the output shafts 111y, 111c, 111BK, the output gears 112y, 112c, 112BK, and the sleeve gear 11 are provided.
3y, 113c, 113BK, and Y developing device 4y, C
The developing device 4c and the BK developing device 4BK are driven.

Next, the driving timing of the Y developing device 4y, the C developing device 4c, the M developing device 4m, the BK developing device 4BK, the timing of pressing the photosensitive drum as a latent image carrier, and the like will be described.

Here, in order to make the explanation easy to understand,
The diameter of the photosensitive drum is 180 mm, the peripheral speed of the photosensitive drum (image forming process speed) is 200 mm / sec, the Y developing unit 4y, the C developing unit 4c, the M developing unit 4m, and the BK
The developing units 4BK are arranged at regular intervals (33.3 ° intervals) between the horizontal 0 ° and the clockwise direction 100 ° with respect to the photosensitive drum. The order of development is as follows: Y developing device 4y, C developing device 4c, M developing device 4m, BK developing device 4B
A case in which continuous copy is performed in the full-color copy mode with the A4 size set to K will be described.

In FIG. 6, the horizontal axis represents time (distance), (a) is a timing chart showing the drive timing of each developing unit, and (b) is a timing chart of the M developing unit 4m. It is an enlarged view.

Lines 1 to 3 from the top of FIG. 6A show the latent image on the photosensitive drum at the developing position (hereinafter referred to as the M developing position) of the M developing device 4m, and the latent image on the photosensitive drum at the developing position of the M developing device 4m. The pressing operation and the ON / OFF operation of the M clutch 110m are shown. In the A4 continuous copy mode, a latent image for two prints is formed during one rotation of the photosensitive drum.
A magenta latent image of the first copy is shown, and M2 is a magenta latent image of the second copy.

Similarly, in FIG.
Line 6 shows the latent image on the photosensitive drum at the developing position of the C developing device 4c (hereinafter referred to as the C developing position), the pressing operation of the C developing device 4c, and the operation of the C clutch 110c. The row indicates the latent image on the photosensitive drum at the developing position of the Y developing device 4y (hereinafter referred to as the Y developing position), the pressing operation of the Y developing device 4y, and the operation of the Y clutch 110y.
The second row includes a latent image on the photosensitive drum at a developing position of the BK developing device 4BK (hereinafter, referred to as a BK developing position) and the BK developing device 4B.
The pressurizing operation of K and the operation of the BK clutch 110BK are shown.

In such a driving device, first, a latent image is started to be formed on the photosensitive drum, and latent images for each color are formed at equal intervals of two A4 size prints on the outer periphery of the photosensitive drum having a diameter of 180 mm. You. At this time, since the outer circumference of the photosensitive drum is 565.2 mm and the width of the A4 size is 210 mm, the intervals of the latent image formation are 72.6 mm and 0.36 mm.
3 seconds.

Next, 0.25 seconds before the leading end of the latent image M1 reaches the M developing position, 50 mm before the pressurization of the M developing device 4m is started.

Also, after 0.05 seconds and 10 mm from the start of pressurization by the M developing device 4m, the M clutch 110m is turned on.
Is done.

Further, 0.05 seconds and 10 mm after the M clutch 110m is turned on, the rotation speed of the developing sleeve as a developer carrier provided in the M developing device 4m reaches a predetermined speed.

Note that, before the pressure applied to the photosensitive drum is completed, the developing device
The rotation speed of the developing sleeve needs to be a predetermined speed. This is because if the rotation speed of the developing sleeve does not reach the predetermined speed, so-called fogging in which unnecessary toner adheres to the photosensitive drum may occur, which may cause a problem in an image.

0.1 m from the start of pressurization by the M developing device 4m.
After 5 seconds and 30 mm, pressurization of the photosensitive drum is completed.
At this time, as described above, the developing sleeve provided in the M developing device 4m rotates at a predetermined speed.

Further, the developing sleeve completes pressurization in front of the front end of the latent image M1 for 0.1 second and with a margin of 20 mm to develop the latent images M1 and M2.

Further, after the development of the latent image M2 is completed, the image is set at 0.
After one second and 20 mm, the separation of the M developing device 4m is started.

As in the case of pressurization, when the developing device is separated from the photosensitive drum, the rotation speed of the developing sleeve needs to be maintained at a predetermined speed. This is because if the rotation speed of the developing sleeve is not maintained at a predetermined speed, fogging may occur and a problem may be caused on an image.
Here, when the M developing device 4m is separated from the photosensitive drum, the M clutch 110m is in the ON state, so that such a problem does not occur.

After 0.05 seconds and 10 mm from the start of the separation operation of the M developing device 4m, the M clutch 110m is turned off.
F.

Also, 0.05 seconds and 10 mm after the M clutch 110m is turned off, the M developing device 4m is completely stopped.

The separation operation is completed 0.15 seconds and 30 mm after the M developing device 4m starts the separation operation.

If the separation operation is not completed before the next latent image C1 reaches the M developing position, the latent image C1 may be developed by the M developing device 4m. The separation operation is completed with a margin of 22.6 mm for 0.113 seconds with respect to the image C1.

Next, the C developing device 4c will be described.

The C developing device 4c is located 33.3 ° upstream of the photosensitive drum in the rotation direction of the photosensitive drum with respect to the M developing device 4m.
At the developing position, the latent image on the photosensitive drum is 0.1 mm from the M developing position.
Reach 261 seconds, 52 mm earlier.

That is, since the timing chart shown in FIG. 6A is expressed on the same time axis, the latent image at the C developing position is 0.261 seconds shorter than the latent image at the M developing position on the timing chart. 52 mm to the left, the latent image M
0.113 seconds after the trailing edge of
After 2.6 mm, the pressurization of the C developing device 4c is started, and the driving of the C developing device 4c is performed similarly to the M developing device 4m.

As for the Y developing device 4y, the Y developing device 4y
y is the rotation direction of the photosensitive drum with respect to the C developing device 4c.
6A, the latent image at the Y development position is shifted by 0.261 seconds and 52 mm leftward from the latent image at the C development position on the timing chart shown in FIG. As in the operation described above, the driving of the Y developing device 4y is performed.

Further, regarding the BK developing device 4BK, BK
Since the developing unit 4BK is located 100 ° downstream of the photosensitive drum in the rotational direction of the photosensitive drum with respect to the Y developing unit 4y, the latent image at the BK developing position is Y in the timing chart shown in FIG.
The image is shifted to the right by 157 mm from the latent image at the developing position for 0.785 seconds, and the BK developing device 4B is shifted similarly to the operation of the C developing device 4c.
The driving of K is performed.

As for the M developing device 4m, the M developing device 4m
m is the rotation direction 3 of the photosensitive drum with respect to the BK developing device 4BK.
6A, the latent image at the M developing position is shifted by 0.261 seconds and 52 mm leftward from the latent image at the BK developing position on the timing chart shown in FIG. Thus, the driving of the Y developing device 4y is performed.

As described above, the driving device includes the Y developing device 4y, the C developing device 4c, the M developing device 4m, the BK developing device 4BK
However, the operation is repeated a predetermined number of times while maintaining the relationship between the drive and the pressurization timing described above.

[0035]

However, in such a driving device, the following problem may occur when the drive transmission of each developing device is switched between the developing devices.

First, the case where the C clutch 110c is turned on will be described.

Immediately before the C clutch 110c is turned on,
The M developing device 4m is in a pressurized state, and the M clutch 110m
Is also in the ON state, and the latent image M2 is being developed. As shown in FIG. 5, the rotational driving force from a driving motor (not shown) is applied to the timing belt 101, the input pulley 102, and the input shaft 1.
03, the distribution gear 104, the M clutch gear 109m, the clutch 110m, the output shaft 111m, the output gear 112m, and the sleeve gear 113m to rotate the M developing device 4m.

Here, when the C clutch 110c is turned on, the rotational driving force from the distribution gear 104 is transmitted to the C clutch gear 109c, the clutch 110c, the output shaft 111c, the output gear 112c, and the sleeve gear 113c, and the C development is performed. Attempts to rotationally drive the container 4c.

At this time, the load and inertia of the C developing device 4c are transmitted to the distribution gear 104 on a path reverse to the drive transmission, and instantaneously reduce the rotation speed of the distribution gear 104.

The decrease in the rotation speed of the distribution gear 104 is as follows.
The power is transmitted to the M clutch gear 109m, the M clutch 110m, the output shaft 111m, the output gear 112m, and the sleeve gear 113m, and finally the rotation speed of the M developing device 4m is reduced.

Further, at this time, the M developing device 4m outputs the latent image M
Since the position of 19.6 mm is being developed for 0.098 seconds from the rear end of 2, if the rotation speed of the developing sleeve provided in the M developing device 4 m decreases, the toner supply to the latent image becomes uneven. Therefore, horizontal streak-like unevenness may occur at the corresponding position on the image.

Next, a case where the M clutch 110m is turned off will be described.

Immediately before the M clutch 110m is turned off, the C developing device 4c is in a pressurized state.
The latent image C1 is being developed while 0c is also in the ON state. FIG.
As shown in FIG. 5, a rotational driving force from a driving motor (not shown) is transmitted via a timing belt 101, an input pulley 102, an input shaft 103, and a distribution gear 104. One of them is an M clutch gear 109m, a clutch 110m, and an output shaft. 111m,
The output is transmitted to the output gear 112m and the sleeve gear 113m to rotationally drive the M developing device 4m. The other is the C clutch gear 109c, the clutch 110c, and the output shaft 111.
c, to the output gear 112c and the sleeve gear 113c to rotate the C developing device 4c.

Here, when the M clutch 110m is turned off, the load on the M developing device 4m is not applied to the distribution gear 104, and the rotation speed of the distribution gear 104 is instantaneously increased.

The increase in the rotation speed of the distribution gear 104 is
The rotation speed of the C developing device 4c is finally increased through the driving system described above.

At this time, since the C developing device 4c is developing at a position of 9.6 mm for 0.048 seconds from the leading end of the latent image C1, the rotation speed of the developing sleeve provided in the C developing device 4c is Rises, the toner supply to the latent image becomes non-uniform, and horizontal streak-like unevenness may occur at the corresponding position on the image.

These disadvantages are not limited to the relationship between the M developing device 4m and the C developing device 4c. When a latent image is being developed by one developing device, the other developing device receives a signal from the drive motor. This may occur when the transmission or the interruption of the rotational driving force is switched.

That is, in such a driving device, FIG.
As shown in (a), when the clutch 110y is turned on while the rear end of the latent image C2 is being developed by the C developing device 4c, the speed decreases (in the figure), and the leading end of the latent image Y1 is developed by the Y developing device 4y. Increases when the clutch 110c is turned off during development (in the figure), the speed increases when the clutch 110m is turned on while developing the leading end of the latent image BK2 by the BK developing unit 4BK (in the figure), and M When the clutch 110BK is turned off while the rear end of the latent image M3 is being developed by the developing device 4m, a speed drop (in the drawing) due to turning off of the clutch 110BK may cause a problem such as a horizontal stripe-like unevenness.

Incidentally, between the Y developing unit 4y and the BK developing unit BK, the developing positions are sufficiently separated from each other, and there is no timing when the two-color clutches are simultaneously ON, so that such a problem does not occur.

In order to avoid such inconveniences, a configuration is adopted in which, while a latent image is being developed by one developing unit, transmission or interruption of the rotational driving force from the driving motor is not switched in another developing unit. Need to be

However, the method of enlarging the diameter of the photosensitive drum to increase the interval between the latent images increases the size of the apparatus. Further, after forming the latent images M1 and M2, the latent image C1 is formed by pulling the photosensitive drum for half a rotation to form a subsequent latent image C1 (without forming the conventional latent image C1 but at the position of the conventional latent image C2). In the method of forming the latent image C2 at the position of the latent image Y1, the printing speed is reduced to 2/3. Further, in the method of performing the developing pressurizing operation and the clutch operation at a high speed, the shock at the time of pressurizing becomes large, disturbing the latent image formation, causing image blurring, and requiring a large capacity of the clutch. This leads to an increase in cost.

Accordingly, the present invention prevents the fluctuation of the rotational speed of the rotational driving force transmitted from the driving source to the developing device without increasing the size and cost of the apparatus, and eliminates horizontal stripe-like unevenness. It is an object of the present invention to provide a driving device capable of obtaining a high-quality image, a developing device including the driving device, and an image forming apparatus.

[0053]

SUMMARY OF THE INVENTION The invention according to the main application is a driving device for selectively transmitting a rotational driving force from one driving source to a plurality of developing devices. A switching unit connected between the developing device and the developing device for transmitting the rotational driving force from the driving source to each of the developing devices so that the rotational driving force can be shut off; and transmitting the rotational driving force to one selected developing device. In the driving device, when the next developing device is switched, the rotational driving force is transmitted to the two developing devices while being temporarily overlapped, and the switching is performed. When transmitting the rotational driving force to the next developing device while transmitting the rotational driving force to the driving device, the driving source and the switching means are configured to maintain the rotational speed of the one developing device within a predetermined value range. Inertia in rotational driving force during A drive device characterized by having an inertia adding means for adding.

Another main invention according to the present application is to provide a latent image carrier that carries a latent image with a developer by applying a developer.
A developing device for making the latent image a visible image, comprising a rotatable developer carrier that is arranged to face the latent image carrier and carries the developer, and the above-described driving device, and the driving device includes: A developing device characterized in that a rotational driving force from a driving source can be transmitted to a developer carrier.

Further, another main aspect of the present invention is an image forming apparatus for recording an image formed by a series of image forming processes on a recording medium, the image forming apparatus including the developing device described above. It is a forming device.

[0056]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a full-color image forming apparatus as an example of an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIG. 1 or FIG.

Such an image forming apparatus has a color image reader section (hereinafter, referred to as "color image reader section") for reading image information from a document.
A digital image printer unit (hereinafter, referred to as a printer unit) that records an image on a recording medium in accordance with image information from the color image reader unit.

In the reader section, as shown in FIG. 1, an original 30 placed on an original platen glass 31 is exposed and scanned by an exposure lamp 32 so that the original 30 condensed by a lens 33 is scanned. Full-color C reflected light image
The CD sensor 34 obtains a color separation image signal.
The color separation image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to a printer unit.

In the printer section, as shown in FIG. 1, a photosensitive drum 1 as a latent image carrier is rotatably supported in the direction of an arrow, and a pre-exposure lamp 11 is provided around the photosensitive drum 1.
Corona charger 2, laser exposure optical system 3, different colors 4
Y developing unit 4y, C developing unit 4c, M developing unit 4m, BK developing unit 4BK, and on-drum light amount detecting means 1
3, a transfer device 5, and a cleaning device 6 are arranged.

The laser exposure optical system 3 reflects a laser beam from a laser output unit (not shown) corresponding to an image signal from the reader unit by a polygon mirror 3a,
The light is irradiated onto the photosensitive drum 1 through the mirror b and the mirror 3c.

At the time of image formation in the printer section, the photosensitive drum 1 is rotated in the direction of the arrow, the photosensitive drum 1 on which the charge has been removed by the pre-exposure lamp 11 is uniformly charged by the charger 2, and an optical image is formed for each separation color. Irradiate E to form a latent image.

Next, a developing device corresponding to each of the separated colors is operated to develop the latent image on the photosensitive drum 1, and the developer is a powder on the photosensitive drum 1 based on a resin and a pigment. A toner image is formed. The Y developing device 4y and the C developing device 4
c, M developing device 4m and BK developing device 4BK are operated by eccentric cams 24y, 24c, 24m and 24Bk, respectively.
The photosensitive drum 1 is selectively approached in accordance with each separation color.

On the other hand, a recording material as a recording medium accommodated in the recording cassette 7 is supplied to a transfer section formed between the photosensitive drum 1 and the transfer device 5 by a transport system, and is transferred onto the photosensitive drum 1 by the transfer device 5. Is transferred. In the present embodiment, the transfer device 5 includes a transfer drum 5a,
A recording material carrying sheet 5f made of a dielectric material is integrally formed in a cylindrical shape on the peripheral opening area of the transfer drum 5a which has an inner charger 5d and an outer charger 5e and is rotatably supported. It is stretched. In the present embodiment, the recording agent carrying sheet 5f uses a dielectric sheet such as a polycarbonate film.

The transfer device 5 has a drum-shaped transfer drum 5a.
Is rotated, the transfer charger 5b transfers the toner image on the photosensitive drum 1 to the recording material carried on the recording material carrying sheet 5f. Thus, the recording material supporting sheet 5f
A desired number of color images are transferred onto the recording material that is electrostatically attracted and conveyed to form a full-color image.

In this image forming apparatus, in the case of forming a full-color image, after the transfer of the four color toner images onto the recording material in this way, the recording material is separated from the separation claw 8a, the separation push-up roller 8b and the separation charging member 8b. The toner is separated from the transfer drum 5 a by the action of the device 5 h, subjected to a fixing process by a heat roller fixing device 9, and discharged to a discharge tray 10.

On the other hand, the photosensitive drum 1 is cleaned by a cleaning device to remove the residual toner remaining on the surface after the transfer process, and is subjected to the image forming process again.

In the image forming apparatus, when images are formed on both sides of the recording material, the conveyance path switching guide 19 is driven immediately after the recording material passes through the fixing device 9 and is subjected to fixing processing. The recording material is transferred to a transfer path 21 via a transport vertical path 20.
After having been guided to the position a, the reversing roller 21b reversely moves the sheet so that the rear end of the sheet is fed, and the sheet is retracted in the direction opposite to the direction in which the sheet is sent. Thereafter, an image is formed on the other surface of the recording material again by the above-described image forming step.

In this embodiment, the transfer drum 5a
And a backup brush 15 facing the fur brush 14 via the recording material supporting sheet 5f in order to prevent scattering and adhesion of powder such as toner on the recording material supporting sheet 5f, and adhesion of oil on the recording material. A backup brush 17 is provided opposite to the oil removing roller 16 via the recording material carrying sheet 5f to perform cleaning before or after image formation, and to perform cleaning as needed in the event of a jam (paper jam).

In this embodiment, the gap between the recording material carrying sheet 5a and the photosensitive drum 1 is reduced by operating the eccentric cam 5 at a desired timing and operating the cam follower 5i integrated with the transfer drum 5f. It can be set arbitrarily. For example, during standby or when the power is off, the transfer drum 5a and the photosensitive drum 1 are separated.

The Y developing device 4y, the C developing device 4c, and the M developing device 4
m, BK developing device 4BK such that a developing sleeve (not shown) as a developer carrying member provided in each developing device is rotationally driven by a rotational driving force from a driving device provided in the image forming apparatus. It has become.

The drive device according to the present embodiment will be described with reference to FIG. FIG. 2 is a development view of the driving device according to the present embodiment.

First, the configuration of the driving device will be described.

As shown in FIG. 2, the driving device is a driving device for driving four developing devices, ie, a Y developing device 4y, a C developing device 4c, an M developing device 4m, and a BK developing device 4BK. A driving motor (not shown) as a driving source, and a Y developing unit 4y, a C developing unit 4c, an M developing unit 4m, B
The rotational driving force from the drive motor connected to the K developing device 4BK is applied to the Y developing device 4y, the C developing device 4c, and M, respectively.
Developing device 4m, BK developing device 4BK
It has an M clutch 110m and a BK clutch 110BK.

Such a driving device, when transmitting the rotational driving force to one selected developing device, applies the rotational driving force to these two developing devices when switching to another selected developing device. The signal is transmitted and switched in a state where it is temporarily overlapped with the developing device.

Further, the driving device according to the present embodiment, when transmitting the rotational driving force to the one developing unit and starting transmitting the rotational driving force to the next developing unit, starts the one developing unit. The drive motor and Y clutch 110y, C clutch 110c, M
The flywheel 203 is provided as inertia imparting means for imparting inertia to the rotational driving force between the clutch 110m and the BK clutch 110BK.

In this driving device, first, the rotational driving force from the driving motor is applied to the timing belt 101.
Thus, the flywheel 203 is transmitted to the input pulley 102, the input shaft 103, and the distribution gear 104, and the flywheel 203 also rotates integrally with the input shaft 103.

The distribution gear 104 has an M clutch gear 109
m, C clutch gear 109c, idler gears 105, 1
07 and the idler gear 105
From the BK through the idler gear 106
The power is transmitted to the clutch gear 109BK and the idler gear 10
7 through the idler gear 108.
The power is transmitted to the clutch gear 109y.

Here, when the M clutch 110m is turned on (transmission state), the output shaft 111m and the output gear 112
m, the M developing device 4m is driven via the sleeve gear 113m.

Similarly, a Y developing device 4y, a C developing device 4c, a B developing device
As for the K developing device 4BK, when the Y clutch 110y, the C clutch 110c, and the BK clutch 110BK are turned on, the output shafts 111y, 111c, 111BK, the output gears 112y, 112c, 112BK, and the sleeve gear 11 are provided.
3y, 113c, 113BK, and Y developing device 4y, C
The developing device 4c and the BK developing device 4BK are driven.

First, the case where the C clutch 110c is turned on will be described.

Immediately before the C clutch 110c is turned on,
The M developing device 4m is in a pressurized state, and the M clutch 110m
Is also in the ON state, and the latent image M2 is being developed. As shown in FIG. 2, the rotational driving force from a driving motor (not shown) is applied to the timing belt 101, the input pulley 102, and the input shaft 1.
03, the distribution gear 104, the M clutch gear 109m, the clutch 110m, the output shaft 111m, the output gear 112m, and the sleeve gear 113m to rotate the M developing device 4m. At this time, the flywheel 203 rotates integrally with the input shaft 103 to keep the rotation speed of the M developing device 4m constant.

When the C-clutch 110c is turned on, the rotational driving force from the distribution gear 104 is transmitted to the C-clutch gear 109c, the clutch 110c, the output shaft 111c, the output gear 112c, and the sleeve gear 113c. Attempts to rotationally drive the container 4c.

At this time, by trying to maintain the rotational speed of the input shaft 103 and the distribution gear 104 by the moment of inertia of the flywheel 203, the load and inertia of the C developing device 4c are applied to the distribution gear 104 through a path reverse to the drive transmission. The instantaneous decrease in the rotation speed of the distribution gear 104 due to the transmission is prevented.

Since the moment of inertia of the flywheel 203 is set to be sufficiently large with respect to the inertia of the rotational driving force of the C developing device 4c, the decrease in the rotational speed of the distribution gear 104 is very small.

As a result, the decrease in the rotation speed of the M developing device 4m is extremely small, is suppressed to a level that does not affect the toner supply to the latent image, and a good image without horizontal streak-like unevenness is obtained. Becomes possible.

Next, the case where the M clutch 110m is turned off will be described.

Immediately before the M clutch 110m is turned off, the C developing device 4c is in a pressurized state.
The latent image C1 is being developed while 0c is also in the ON state. FIG.
As shown in FIG. 5, a rotational driving force from a driving motor (not shown) is transmitted via a timing belt 101, an input pulley 102, an input shaft 103, and a distribution gear 104. One of them is an M clutch gear 109m, a clutch 110m, and an output shaft. 111m,
The output is transmitted to the output gear 112m and the sleeve gear 113m to rotationally drive the M developing device 4m. The other is the C clutch gear 109c, the clutch 110c, and the output shaft 111.
c, to the output gear 112c and the sleeve gear 113c to rotate the C developing device 4c. At this time, the flywheel 203 rotates integrally with the input shaft 103,
The rotation speeds of the M developing device 4m and the C developing device 4c are to be kept constant.

Here, by trying to maintain the rotational speed of the input shaft 103 and the distribution gear 104 by the moment of inertia of the flywheel 203, the M clutch 110m
When the FF is performed, the load of the M developing device 4m is distributed to the distribution gear 104.
This prevents an instantaneous increase in the rotation speed of the distribution gear 104 due to the absence of the gear.

Since the moment of inertia of the flywheel 203 is set sufficiently large with respect to the inertia of the rotational driving force of the M developing device 4m, the increase in the rotational speed of the distribution gear 104 is very small.

As a result, the increase in the rotation speed of the C developing device 4c is extremely small, and is suppressed to a level that does not affect the toner supply to the latent image, and a good image without horizontal stripe-like unevenness can be obtained. Becomes possible.

The effect of the flywheel 203 is not limited to the relationship between the M developing device 4m and the C developing device 4c. When a latent image is developed by one developing device, All the effects are obtained with respect to the horizontal streak-like unevenness when switching of transmission or interruption of the rotational driving force from the drive motor is performed.

That is, in such a driving device, FIG.
As shown in (a), when the clutch 110y is turned on while the rear end of the latent image C2 is being developed by the C developing device 4c, the speed decreases (in the figure), and the leading end of the latent image Y1 is developed by the Y developing device 4y. , The speed is increased by turning off the clutch 110c during development (in the figure), the speed is reduced by turning on the clutch 110m while developing the front end of the latent image BK2 by the BK developing unit 4BK, and M This is effective for all horizontal stripe-like unevenness caused by a speed increase (in the drawing) caused by the clutch 110BK being turned off while the rear end of the latent image M3 is being developed by the developing device 4m.

Since the developing positions of the Y developing device 4y and the BK developing device BK are sufficiently far from each other and there is no timing when the two color clutches are simultaneously turned on, such a problem does not occur.

In this embodiment, as shown in FIG. 2, the distribution gear 104 is formed integrally with the flywheel 203, and the M clutch 110m and the C clutch 110c are connected to the distribution gear 104 and the flywheel 203, respectively. 203.

Similarly, C clutch 110c and Y clutch 110y, BK clutch 110BK and M clutch 1
10m is connected via a distribution gear 104, and all the clutches operating simultaneously are connected to each other via a flywheel 203.

As described above, even when there is a disturbance such that the next other color clutch is turned on / off during the development of one developing unit, the normal rotation speed of the developing unit is maintained at a high level by the flywheel 203. Since the image is kept at a constant speed, fine unevenness of the image is eliminated and a smooth high-quality image can be obtained. In particular, in the case of printing a halftone image uniformly with a relatively low density of four color toners, the above-described effects become remarkable.

Therefore, according to the present embodiment, the flywheel 203 applies the inertia to the rotational driving force between the drive motor and the C clutch 110c, the Y clutch 110y, the BK clutch 110BK, and the M clutch 110m,
When the clutch 110c, the Y clutch 110y, the BK clutch 110BK, and the M clutch 110m are transmitting the rotational driving force from the drive motor to the selected one of the developing devices, when switching to the next selected developing device. Since the rotational driving force is transmitted and switched in a state of being temporarily connected to these two developing units while being overlapped, the driving motor can be used without increasing the size and cost of the apparatus. It is possible to prevent fluctuations in the rotational speed of the rotational driving force transmitted to each developing device, and to obtain a high-quality image without horizontal streak-like unevenness.

(Second Embodiment) Next, a second embodiment of the present invention will be described. Note that the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

As described in the first embodiment, if the fixed state of the input shaft 103 and the distribution gear 104 is a state in which there is no play, the above-described configuration is sufficient, but a general fixing method ( For example, in a state where there is a little backlash by a method in which a parallel pin is fitted into a groove of a gear to prevent the gear from rotating around an axis, the following configuration is preferable.

In the driving device according to the present embodiment,
As shown in FIG. 3, the distribution gear is divided into two to form distribution gears 104a and 104b, and the distribution gears 104a and 104b are divided.
Are fixed to the input shaft 103 integral with the flywheel 203, respectively.

In this embodiment, a parallel pin (not shown) is inserted into a through hole (not shown) formed in the input shaft 103 by using a general fixing method, and the end of the parallel pin is inserted. The distribution gears 104a, 104b are fixed to the input shaft 103 by fitting the parts into grooves (not shown) formed in the distribution gears 104a, 104b to prevent rotation.

The C clutch 110c and the Y clutch 110y
In relation to the above, the decrease in the rotation speed of the C developing device 4c due to the turning on of the Y clutch 110y is caused by the idler gears 108 and 107 and the distribution gear 104 starting from the gear 109y.
a, but when transmitted from the distribution gear 104a to the input shaft 103, can be kept very small due to the inertia of the flywheel 203.

The gear to the C clutch 110c is the input shaft 1
Since the rotation is performed by the rotation of No. 03, a decrease in the rotation speed to the C developing device 4c is extremely small, and a good image can be obtained.

Similarly, the relationship between the BK clutch 110BK and the M clutch 110m also indicates that the rotation speed of the BK developing device 4BK is reduced by turning on the M clutch 110m.
Since the light is transmitted to the distribution gear 104a via the third gear 3, the size of the transmission gear is extremely small, and a good image can be obtained.

Therefore, according to the present embodiment, the flywheel 203 is connected to the drive motor by the flywheel 20.
C clutch 110c, Y clutch 110y, BK clutch 110BK, M clutch 110
m while applying inertia to the rotational driving force between the C clutch 110c, the Y clutch 110y, and the BK clutch 110.
When the BK / M clutch 110m is transmitting the rotational driving force from the drive motor to the selected one of the developing devices, the rotational driving force is applied to these two developing devices at the next switching to the selected developing device. Rotational drive transmitted from the drive motor to each developing unit without having to increase the size and cost of the device, because transmission and switching are performed while being temporarily connected to the developing unit in an overlapping manner. It is possible to prevent fluctuations in the rotational speed of the force and to obtain a high-quality image without horizontal stripe-like unevenness.

(Third Embodiment) Next, a third embodiment of the present invention will be described. Note that the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

The M clutch 110m and the C clutch 110c
In order to improve the relationship with the above, it is preferable to configure as follows.

In the present embodiment, as shown in FIG. 4, the distribution gear is further divided into divided gears 104a, 104b, and 104c as compared with the second embodiment.
The a, 104b, and 104c are fixed to the input shaft 103 integrally formed with the flywheel 203, respectively, by a common fixing method as in the second embodiment.

As a result, a decrease in the rotation speed of the M developing device 4m due to the turning on of the C clutch 110c is transmitted from the distribution gear 104b to the distribution gear 104c via the flywheel 203, but is transmitted through the flywheel 203. The decrease in the rotation speed is suppressed to a very small value, and a good image can be obtained.

Similarly, when the Y clutch 110y and the M clutch 110m are turned on, the rotation speeds of the C developing device 4c and the BK developing device 4BK decrease, respectively.
a, transmitted to the distribution gear 104b and the distribution gear 104a from the distribution gear 104c via the flywheel 203, respectively, but both are transmitted via the flywheel 203, so that the decrease in the rotation speed is suppressed to a very small level and a good image is obtained. Is possible.

In this embodiment, the example in which the flywheel 203 is disposed outside the pulley 102 has been described. However, the present invention is not limited to this.
On the developing device side, between the side plates 115 and 114.
Further, the distribution gear 104 may also be used as a flywheel.

Therefore, according to the present embodiment, the flywheel 203 is connected to the drive motor by the flywheel 20.
C clutch 110c, Y clutch 110y, BK clutch 110BK, M clutch 110
m while applying inertia to the rotational driving force between the C clutch 110c, the Y clutch 110y, and the BK clutch 110.
When the BK / M clutch 110m is transmitting the rotational driving force from the drive motor to the selected one of the developing devices, the rotational driving force is applied to these two developing devices at the next switching to the selected developing device. Rotational drive transmitted from the drive motor to each developing unit without having to increase the size and cost of the device, because transmission and switching are performed while being temporarily connected to the developing unit in an overlapping manner. It is possible to prevent fluctuations in the rotational speed of the force and to obtain a high-quality image without horizontal stripe-like unevenness.

[0114]

As described above, according to the present invention, fluctuations in the rotational speed of the rotational driving force transmitted from the driving source to the developing device can be prevented without increasing the size and cost of the apparatus. In addition, it is possible to obtain a high-quality image without horizontal streak-like unevenness.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view illustrating a schematic configuration of a full-color image forming apparatus as an example of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a development view illustrating a schematic configuration of a driving device provided in the image forming apparatus of FIG.

FIG. 3 is a development view showing a schematic configuration of a driving device according to a second embodiment of the present invention.

FIG. 4 is a development view showing a schematic configuration of a driving device according to a third embodiment of the present invention.

FIG. 5 is a development view showing a schematic configuration of a conventional driving device.

FIG. 6 is a timing chart showing the drive timing of each developing device in the drive device of FIG.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum (latent image carrier) 4m M developing device (developing device) 4c C developing device (developing device) 4y Y developing device (developing device) 4BK BK developing device (developing device) 110m M clutch (switching means) 110c C Clutch (switching means) 110y Y clutch (switching means) 110BK BK clutch (switching means) 203 Flywheel (inertia imparting means)

Continued on the front page F term (reference) 2H027 EA04 EB04 ED02 ED08 EE01 EE04 EF01 2H030 AD17 BB02 BB24 BB33 2H071 CA01 CA05 CA07 DA08 DA27 EA18 2H077 AD02 AD04 BA03 BA04 BA10 GA13 3J009 DA20 EA05 EA21 EA21 EA21

Claims (5)

[Claims] 1. A driving device for selectively transmitting a rotational driving force from one driving source to a plurality of developing devices,
A switching unit connected between the driving source and each of the developing devices and configured to transmit the rotational driving force from the driving source to each of the developing devices so that the rotational driving force can be shut off to each of the developing devices; A driving device that transmits and switches the rotational driving force to the two developing devices in a state of being temporarily connected to the two developing devices at the time of switching to the next selected developing device. When the transmission of the rotational driving force to the next developing device is started while the rotational driving force is being transmitted to the one developing device, the driving is performed such that the rotational speed of the one developing device is maintained within a predetermined value range. A drive device comprising: inertia imparting means for imparting inertia to a rotational driving force between a source and a switching means. 2. The drive device according to claim 1, wherein the inertia imparting means is a disk-shaped flywheel connected between the drive source and the switching means. 3. The driving device according to claim 1, wherein the switching means is provided for each of the plurality of developing devices, and the switching means are connected to each other via an inertia providing means. apparatus. 4. A developing device for applying a developer to a latent image carrier for carrying a latent image to convert the latent image into a visible image, wherein the developing device is disposed to face the latent image carrier. And a drive device according to any one of claims 1 to 3, wherein the drive device is capable of transmitting a rotational driving force from a drive source to the developer support. A developing device. 5. An image forming apparatus for recording an image formed by a series of image forming processes on a recording medium,
An image forming apparatus comprising the developing device according to claim 4.