JPH04368964A - Image forming device - Google Patents

Abstract

PURPOSE:To provide the image forming device where rotational force on a device main body side can be accurately transmitted to a processing cartridge side and without uneveness in rotation when the processing cartridge is loaded. CONSTITUTION:A pulley 20 is provided on either the side of the processing cartridge 5 or the side of a device main body 100. A flat belt 24 is provided on the other side where driving force is transmitted between the before mentioned pulley 20 and able to came into contact or separate from this pulley 20 at the same time. One of the flat belt 24 or the pulley 20 which is on the device main body 100 side is rotated and driven by a driving source 28 on the device main body 100 side. Therefore, a smooth rotation without unevenness in rotation by friction transmission between the pulley 20 and the flat belt 24 can be transmitted to the processing cartridge 5. Furthermore, only the pulley 20 and the flat belt 24 need to be abutted to each other, the positioning of these is facilitated, and rotation is also accurately transmitted when the processing cartridge 5 is loaded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus equipped with a process cartridge.

0002

2. Description of the Related Art In image forming apparatuses such as copying machines and laser beam printers, in order to facilitate maintenance, a photosensitive drum serving as an image carrier, a developing device, etc. are integrally provided. Many devices are equipped with a process cartridge that is removably installed inside the device body. In this case, it is necessary to rotate the photosensitive drum and the like in the process cartridge using a drive source on the apparatus main body side. For this reason, a driven gear is provided on the process cartridge side and a driving gear is provided on the apparatus main body side, and when installing the process cartridge into the apparatus main body, the driven gear and the driving gear are meshed to move the photosensitive drum, etc. inside the process cartridge. Many of them are rotated through gears.

0003

[Problems to be Solved by the Invention] However, in the conventional example described above, when installing the process cartridge into the apparatus main body, the driven gear on the process cartridge side and the driving gear on the apparatus main body side often do not mesh with precision. In this case, there was a problem in that the rotation accuracy of the photosensitive drum etc. deteriorated.

[0004] Furthermore, since the photosensitive drum etc. in the process cartridge are rotated from the apparatus main body side via gears,
There is a problem in that the image bearing member rotates unevenly due to gear backlash and the like, resulting in a reduction in image quality.

The present invention has been made in view of the above problems, and its object is to apply the rotational force of the mounting body to the rotating body of the process cartridge with high precision and without rotational unevenness when mounting the process cartridge. An object of the present invention is to provide an image forming apparatus capable of transmitting images.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes at least an image carrier and one developing means,
In an image forming apparatus equipped with a process cartridge that is removably disposed within the image forming apparatus main body, a pulley is provided on one side of the process cartridge and the image forming apparatus main body.
Power can be transmitted between this pulley on the other side, and
The present invention is characterized in that a flat belt that can come into contact with and separate from the pulley is provided, and the flat belt or the pulley located on the image forming apparatus main body side is rotationally driven by a drive source on the image forming apparatus main body side.

[0007]

[Operation] A pulley is provided on one side of the process cartridge and the main body of the apparatus, and a flat belt capable of transmitting power between the pulley and the pulley is provided on the other side. Therefore, when the process cartridge is installed in the image forming apparatus main body and the pulley is brought into contact with the flat belt, the rotational force of the drive source on the image forming apparatus main body side is transferred to the process cartridge side by friction transmission via the pulley and the flat belt. The rotation will be transmitted smoothly and without unevenness.

[0008] Furthermore, the process cartridge can be attached to the main body of the apparatus by simply bringing the pulley into contact with the flat belt, which is relatively easy compared to the case of gears. will be communicated with high accuracy.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings.

First, a first embodiment of the present invention will be explained with reference to FIGS. 1 to 4.
This is explained by:

FIG. 3 shows a cross section of an image forming apparatus capable of forming a multicolor image. In the figure, 1 is a photosensitive drum which is an image bearing member that rotates in a fixed direction. roller 2, four developing devices 3 (specifically yellow,
Magenta, cyan, black developing devices 3A, 3B, 3C,
3D) and a cleaning device 4 are provided. These process devices are integrally housed in a cartridge container 5a, and are removably disposed in the apparatus main body 100 as a process cartridge 5 to facilitate maintenance.

A transfer drum 6 that holds a transfer material and rotates is disposed on one side of the photosensitive drum 1. A paper feed unit 7 is provided on the paper feed side of the transfer drum 6, and a fixing unit 8 is provided on the paper discharge side of the transfer drum 6.
are arranged respectively. Furthermore, an optical unit 9 is disposed above the process cartridge 5.

That is, when the photosensitive drum 1 uniformly charged by the charging roller 2 is exposed to the image light L of the yellow image information through the optical unit 9, an electrostatic latent image is formed on the photosensitive drum 1. As the photosensitive drum 1 rotates, the electrostatic latent image is directed toward a yellow developing device 3A containing yellow toner, and is visualized as a toner image by the yellow developing device 3A. This toner image is then transferred to the photosensitive drum 1.
As the photosensitive drum 1 rotates, the image is transferred onto a transfer material on a transfer drum 6 that rotates in conjunction with the photosensitive drum 1.

After the transfer has been completed, the photosensitive drum 1 is cleaned by a cleaning device 4, then uniformly charged by a charging roller 2 again, and exposed to image light L of magenta image information via an optical unit 9. An electrostatic latent image is formed on this photosensitive drum 1. Then, this electrostatic latent image is visualized as a toner image by a magenta developing device 3B having magenta toner, and this toner image is transferred onto the transfer drum 6, which rotates in synchronization with the toner image. Multiple transfers are made to the material. Similarly, toner images formed on the photosensitive drum 1 via the cyan and black developing devices 3C and 3D based on the cyan and black image information are multiple-transferred onto the transfer material.

On the other hand, the transfer material in the paper feeding unit 7 is supplied to the transfer drum 6, and after being positioned and held by the transfer drum 6, toners of each color are deposited on the transfer material as the transfer drum 6 rotates as described above. Multiple images are transferred. After the transfer, the transfer material is transferred from the transfer drum 6 to the fixing unit 8.
The toner image is heated, pressurized, melted and mixed in color in the fixing unit 8, and fixed as a permanent image, and then stacked on the paper discharge tray 50.

Now, next, the process cartridge 5 is connected to the photosensitive drum 1 etc., which is a characteristic feature of the present invention.
The means for transmitting the driving force from the 0 side will be explained with reference to FIGS. 1 and 2.

In the process cartridge 5, the drum shaft 1a of the photosensitive drum 1 protruding outward from the cartridge container 5a is supported by the bearing portions 10a, 10a of the main body frames 10, 10 of the apparatus main body 100, so that the process cartridge 5 can be inserted into the apparatus main body. Positioning is supported. That is, the main body frame 10,
10 bearing parts 10a, 10a have bearing parts 10a, 10a.
A guide groove (not shown) leading to the drum shaft 1a is formed, and the process cartridge 5 can be attached to and detached from the apparatus main body 100 by inserting both ends of the drum shaft 1a into the guide groove. A drum pulley 20 that can rotate the photosensitive drum 1 and the like in the process cartridge 5 is fixed to one end of the drum shaft 1a.

On the other hand, on the side of the drum pulley 20 in the apparatus main body 100, the first and second pulleys 21, 22 and the swinging pulley 23 are stretched in a triangular shape as shown by the broken line in FIG. An endless flat belt 24 that can rotate and transmit rotational force to the drum pulley 20 is provided. The first and second pulleys 21 and 22 are positioned and pivotally supported by a support part (not shown) of the device main body 100, and the swing pulley 23 is located at one end of a swing plate 26 that is swingable via a support shaft 25. It is pivotally supported on the side and is movable as the swing plate 26 rotates. A spring member 27 is attached to the other end of the swing plate 26, and the swing plate 26 is connected to the support shaft 25.
2 in the counterclockwise direction in FIG. 2 to apply a constant tension to the flat belt 24.

Furthermore, as shown in FIG. 1, the first pulley 21 can be rotated by a drive motor 28 provided on the device main body 100 side via first and second gears 29 and 30, which are reduction gears. As the first pulley 21 rotates, the flat belt 24 can be rotated in a predetermined direction via the second pulley 22 and the swing pulley 23.

Here, the first and second pulleys 21 and 22, the swing pulley 23, and the drum pulley 20 are provided with crowns of appropriate heights, and the surfaces of the pulleys 21 and 22 that come into contact with the flat belt 24 are covered with crowns. In order to increase the frictional force between the pulley surface and the pulley surface, high friction treatments such as ceramic spraying or urethane coating are applied. Further, the flat belt 24 is a polyester woven belt in this embodiment, and its surface material is made of polyurethane, but an endless metal belt such as SUS may also be used.

When the process cartridge 5 is installed in the apparatus main body 100 and both ends of the drum shaft 1a are positioned and supported by the bearings 10a, 10a of the main body frames 10, 10, as shown in FIG. The drum pulley 20 presses the flat belt 24 between the first and second pulleys 21 and 22 on the device main body 100 side toward the swing pulley 23 to curve the flat belt 24 inward from the straight state shown by the broken line. do.

On the other hand, as a result, the flat belt 24 receives extra tension and tends to pull the swing pulley 23 toward the drum pulley 20. Therefore, the swing plate 26 rotates clockwise around the support shaft 25 against the elastic force of the spring member 27, moves the swing pulley 23 slightly toward the drum pulley 20, and moves the flat belt 24 along the broken line. From the state to the solid line state,
An attempt is made to maintain the tension of this flat belt at a constant value.

Therefore, the flat belt 24 becomes U-shaped and comes into sufficient contact with the drum pulley 20, and
The flat belt 24 is pressed against the drum pulley 20 with a predetermined force, and the drum pulley 20 can be sufficiently rotated by the flat belt 24.

In this state, the drive motor 28 rotates, and the rotation of the drive motor 28 is controlled by the first and second gears 29 and 3.
When the flat belt 24 is decelerated by 0 and transmitted to the first pulley 21, the flat belt 24 rotates while rotating the drum pulley 20, the second pulley 22, and the swing pulley 23. The photosensitive drum 1 and the like inside the process cartridge 5 are rotated.

As described above, since the rotational force of the drive motor 28 on the apparatus main body 100 side is transmitted to the photosensitive drum 1 etc. on the process cartridge 5 side by friction transmission by the pulleys 20, 21, 22, 23 and the flat belt 24, Compared to the case of using gears, geared belts, etc., there is no rotational unevenness caused by gear backlash (pitch unevenness that occurs at each meshing pitch of teeth), and the photosensitive drum 1 etc. can rotate smoothly at a constant speed. becomes. Similarly, when installing the process cartridge 5, there is no need to mesh the gears, so the operability of the process cartridge 5 is improved, and there is no interference between the tips of the gears when the process cartridge 5 is installed. Since there is no damage to the teeth caused by this, pitch unevenness caused by this damage to the teeth does not occur. In addition, a small module (m=0.2
~0.3), the above process cartridge 5
Although this improves the operability of the gear, it does not prevent interference from the tips of the gear teeth.

Furthermore, since the power can be easily transmitted between the process cartridge 5 side and the apparatus main body 100 side by simply pressing the drum pulley 20 against the flat belt 24, the meshing of the gears is easier than when gears are used. There is no problem that the rotation accuracy of the photosensitive drum 1 and the like on the process cartridge 5 side is lowered due to accuracy. Furthermore, the inconvenience that load fluctuations on the cleaning device 4 and transfer drum 6 are directly linked to fluctuations in the rotational speed of the photosensitive drum 1 is eliminated.

Furthermore, if the flat belt 24 or the like is used, the reduction ratio can be increased compared to the case where gears are used, and the drive motor 28 on the apparatus main body 100 side, the flat belt 24, etc., and the photosensitive drum 1 of the process cartridge 5 can be used. As shown, the drive motor 28 and the photosensitive drum 1 are connected via the flat belt feeding mechanism.
Since it can be directly connected to the motor, it can be expected to have an effect similar to that of a DD motor, and has the advantage of reducing image unevenness.

[0028] Here, the flat belt 24 is used instead of other friction-feeding belts such as V-belts and round belts because the flat belt 24 is very thin (its thickness is 0.5 to 0.5 mm). 0
．． This is because the belt pitch circumference has small errors (approximately 1 mm), and has the characteristics that there is little change in pitch circumference due to temperature changes, and little change in pitch circumference due to load fluctuations. This is because it is more suitable for precision transmission than. Particularly, in the case of a metal flat belt, in addition to the above-mentioned characteristics, it also has the characteristic that the elongation of the belt due to load fluctuations can be reduced.

Furthermore, as shown in FIG. 4, the drive motor 2
If 8 is configured with a motor that can rotate at low speed, such as an ultrasonic motor or a 5-phase stepping motor, the first pulley 21 can be attached directly to the motor shaft, and the first and second gears 29, 3
A reduction gear such as 0 can be omitted. In this case, since the rotational force of the drive motor 28 can be directly transmitted to the first pulley 21 without using the first and second gears 29 and 30, the rotation of the photosensitive drum 1 etc. in the process cartridge 5 can be made more even and smooth. Become.

Next, a second embodiment of the present invention will be described with reference to FIGS. 5 to 7.
This is explained by: Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In this embodiment, the flat belt 24 which has been pressed and curved by the drum pulley 20 is pressed against a pressing pulley 32 disposed on the back side of the flat belt 24, and the pressing pulley 32 also presses the flat belt 24. Sufficient pressure is applied to the drum pulley 20 side.

That is, as shown in FIGS. 6 and 7, a pressure pulley 32 is pivotally supported at one end of a support plate 31 supported by support shafts 11, 11 on the apparatus main body 100 side via elongated holes 31a, 31a. At the same time, the other end of the support plate 31 is biased toward the right in FIG. 6 via the spring member 33. The pressing pulley 32 includes the first and second pulleys 21, 22 and the swing pulley 23.
The support plate 31 is biased to the right in FIG. 6 by a spring member 33, and the support plate 31 is positioned inside the flat belt 24 stretched over the The pressing pulley 32 is also moved to the right by an amount that has been moved to the right with respect to the support shaft 11 by the length.

The process cartridge 5 is mounted on the bearing portions 10a, 1 of the main body frames 10, 10 of the apparatus main body 100.
0a, the drum pulley 20 is attached to the flat belt 24 between the first and second pulleys 21 and 22, as shown in FIG.
is pressed and curved, and the swinging plate 26 is caused to swing clockwise in FIG. 6 via the support shaft 25 against the elastic force of the spring 27. In this case, the pressing pulley 32 pivotally supported by the support plate 31 is pressed to the left side in FIG. 6 by the drum pulley 20 via the flat belt 24.
2 is a spring member 3 corresponding to the length of the substantially elongated hole 31a of the support plate 31.
Since the flat belt 24 can be moved to the left against the elastic force of 3, the flat belt 24 is pressed toward the drum pulley 20 by the spring member 33 via the pressing pulley 32.

That is, since the flat belt 24 is pressed toward the drum pulley 20 not only by the spring member 27 but also by the spring member 33, the rotational force of the drive motor 28, which is rotated at a reduced speed through this flat belt, is further reduced. This means that the signal can be reliably transmitted to the drum pulley 20 side, and in this embodiment, it is possible to obtain an effect equal to or greater than that of the first embodiment.

Next, a third embodiment of the present invention will be described with reference to FIGS. 8 to 1.
This will be explained using 0. Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In this embodiment, in addition to the drum pulley 20, there are two tension pulleys 34 and 3 on the process cartridge 5 side.
5, and a flat belt 36 is stretched between these three pulleys 20, 34, and 35. Further, on the apparatus main body 100 side, a motor shaft of a drive motor 28 capable of decelerating rotation is pressed by the flat belt 36 and the rotational force is transferred to the flat belt 36.
Attach a drive pulley 37 that can be transmitted to.

Then, the process cartridge 5 is attached to the main body frames 10, 1 of the apparatus main body 100 via the drum shaft 1a.
10, the flat belt 36 between the tension pulleys 34 and 35 presses the drive pulley 37, as shown in FIG. 10, and the flat belt 36 deforms into a dogleg shape. Therefore, the flat belt 36 is connected to the drive pulley 3
7 with a certain pressing force, and if the drive pulley 37 is rotated via the drive motor 28,
The flat belt 36 rotates via the drive pulley 37 and rotates the drum pulley 20. Therefore, the same effects as in the first embodiment can be obtained in this embodiment as well.

[0038]

Effects of the Invention As is clear from the above description, according to the present invention, the rotational force on the image forming apparatus main body side can be transmitted to the process cartridge side by frictional transmission via the pulley and the flat belt. The rotating body rotates smoothly without rotational unevenness, and there is no deterioration in image quality.

Furthermore, when installing the process cartridge into the image forming apparatus main body, the pulley and the flat belt only need to be brought into contact with each other, which makes the work easier, and the rotational force from the image forming apparatus main body is accurately transferred to the process cartridge side. This eliminates the inconvenience of not being able to convey information to others.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a state in which a process cartridge is installed in the main body of an image forming apparatus according to a first embodiment.

FIG. 2 is an explanatory diagram of the operation of a driving force transmitting means that transmits rotational force to the process cartridge side of the image forming apparatus.

FIG. 3 is a side sectional view of the image forming apparatus.

FIG. 4 is a diagram showing a state in which a process cartridge is installed in the apparatus main body of an image forming apparatus according to a modified example of the first embodiment.

FIG. 5 is a diagram showing a state in which a process cartridge is installed in the apparatus main body of an image forming apparatus according to a second embodiment.

FIG. 6 is an explanatory diagram of the operation of a driving force transmitting means that transmits rotational force to the process cartridge side of the image forming apparatus.

FIG. 7 is an enlarged view of the support plate and drum pulley of the image forming apparatus.

FIG. 8 is a diagram showing a state in which a process cartridge is installed in the apparatus main body of an image forming apparatus according to a third embodiment.

FIG. 9 is a diagram showing the state of a flat belt, etc. in a process cartridge of the image forming apparatus.

FIG. 10 is an explanatory diagram of the operation of a driving force transmitting means that transmits rotational force to the process cartridge side of the image forming apparatus.

[Explanation of symbols]

1 Photosensitive drum (image carrier) 3
Developing device (developing means) 5 Process cartridge 20 Drum pulley (pulley) 24 Flat belt

Claims (1)

[Claims] Claim 1: In an image forming apparatus equipped with a process cartridge that has at least an image bearing member and one developing unit and that is removably disposed within the image forming apparatus main body, the process cartridge and the image forming apparatus main body are connected to each other. A pulley is provided on one inner side, and a flat belt capable of transmitting power between the pulley and the pulley on the other side and capable of coming into contact with and separating from the pulley is provided, and the flat belt or pulley is located on the side of the main body of the image forming apparatus. An image forming apparatus characterized in that an object is rotationally driven by a drive source on the main body side of the image forming apparatus.