JP2002040739A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of easily controlling an image forming speed while suppressing the reduction of image quality and the increase of the cost, and also, capable of attaining the miniaturization. SOLUTION: As for the image forming device provided with plural image forming parts P equipped with a photoreceptor drum (image carrier) 201, a contact type electrifying device (electrifying device) 202 for applying a charge on the photoreceptor drum 201 and a developing device 203 for developing a latent image formed on the photoreceptor drum 201 and for forming the image on a recording medium, each drive with reference to the photoreceptor drum 201, the electrifying device 202 and the developing device 203 in the same image forming part P is inputted into the image forming part through an individual path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a full-color copying machine or a printer having a plurality of image forming units and forming an image on a recording medium by an electrophotographic system.

[0002]

2. Description of the Related Art First, an image forming process in a full-color image forming apparatus employing an electrophotographic system will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating the configuration of the full-color image forming apparatus. The full-color image forming apparatus includes first, second, third, and fourth four image forming units Pa and P.
b, Pc and Pd are juxtaposed. Thus, a cassette 101 containing a recording medium (hereinafter, referred to as recording paper)
The first, second, third, and fourth image forming units Pa, Pb, Pc
An endless belt-shaped recording paper transport belt (hereinafter, simply referred to as a transport belt) 103 that circulates to transport the recording paper through these image forming units Pa to Pd is provided below Pd and Pd. Have been.

The transport belt 103 includes a driving roller 104
3 is driven endlessly in the direction of arrow A in FIG. 3, and the recording paper is fed out of the cassette 101 and fed synchronously by the pair of registration rollers 105.
3, the image forming units Pa, Pb, Pc and P
d. The fixing device 102 is the transport belt 1
03, the recording paper discharged from the drive roller 104 side is received, and in the image forming units Pa, Pb, Pc, and Pd, the toner images of the respective colors transferred to the recording paper in a superimposed manner are collectively fixed to form a permanent image. The output recording paper is sent to the output tray 10
It is discharged to 6.

[0004]

FIG. 3 shows the details of the image forming section. Since all the image forming sections Pa to Pd are structurally the same, the configuration of the image forming section P will be described here. I do.

In the image forming section P, the photosensitive drum 201 is rotated from the upstream side in the rotation direction (the direction of arrow B in the drawing) of the photosensitive drum 201.
Rotating body contact charging device 202 for uniformly charging
An LED head array 203 for forming a latent image and a developing device 204 for visualizing the latent image with toner of each color are provided. Here, the photosensitive drum 201, the contact charging device 202, and the developing device 204 are rotationally driven in directions of arrows B, C, and D by a driving source (not shown).

Generally, in order to stabilize the charged state and the developed state, the rotating peripheral speed of the rotating body contact charging device 202 and the developing device 204 is increased by about 20% to 50% with respect to the rotating peripheral speed of the photosensitive drum 201. It is driven in a speedy state.

Here, since the rotation unevenness of the photosensitive drum 201 is directly linked to the deterioration of image quality, the photosensitive drum 201 needs to be driven precisely. On the other hand, the rotation unevenness of the rotating body contact charging device 202 and the developing device 204 is not uniform.
It is tolerable to some extent as compared with the rotation unevenness of 01. For example, if the driving source of the photosensitive drum 201 is the same as the driving source of the rotating body contact charging device 202 and the developing device 204, the rotating body contact charging device 20 is required for rotation of the photosensitive drum 201 requiring accuracy.
2 and uneven rotation of the developing device 204 may have an adverse effect.

Therefore, a drive source for driving other devices besides the drive source for the photosensitive drum 201 is provided.

However, in the full-color image forming apparatus employing the four-tandem tandem system as shown in FIG. 2, since the image forming units Pa to Pd are close to each other, the photosensitive drum 2
When the drive source No. 01 is disposed, it is very difficult to dispose the drive sources for other devices in substantially the same plane. Further, even if the driving sources can be provided, the number of driving units increases by the number of the image forming units Pa to Pd.

Further, when the driving start timings of the charging device and the developing device are different from each other or when the running cost in black-and-white printing is suppressed, the color image forming unit is provided with an electromagnetic clutch for switching the transmission / non-transmission of the driving force. Often provided. In addition, as described above, it is necessary to provide a mechanism for increasing the speed of another device with respect to the photosensitive drum 201, and thus the size and cost of the device are increased.

Further, when the transmission / non-transmission of the driving force is switched by providing the electromagnetic clutch as described above, if the other device is driven by using the drive source of the photosensitive drum, the transmission / non-transmission of the driving force is switched. The generated shock is transmitted directly to the photosensitive drum, which leads to a reduction in image quality. Further, depending on the type of recording paper, the image forming speed of the image forming apparatus may be changed. In particular, thick paper or a sheet using a special material (eg, a transparency sheet)
For example, when an image is formed, control is performed such that the image forming speed is reduced to increase the time required for the fixing process, but it is necessary to change the drive speed of the photosensitive drum and other devices.

Further, when a portion shown by a two-dot chain line in FIG.
The drive transmission portion is further complicated. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of easily performing image forming speed control while minimizing downsizing while suppressing deterioration in image quality and cost. To provide an image forming apparatus capable of performing the above.

[0013]

In order to achieve the above object, according to the present invention, there is provided an image bearing member, a charging device for applying a charge to the image bearing member, and an image bearing member formed on the image bearing member. An image forming apparatus including a plurality of image forming units including a developing device for visualizing a latent image and forming an image on a recording medium,
Each drive of the image carrier, the charging device, and the developing device in the same image forming unit is input to the image forming unit via different paths.

According to a second aspect of the present invention, there is provided an image bearing member, a charging device for applying a charge to the image bearing member by employing a rotating body contact charging system, and a latent image formed on the image bearing member is visualized. A plurality of image forming units each including a developing device for forming an image on a recording medium, and driving the image carrier, the charging device, and the developing device in the same image forming unit through different paths. Input to the image forming unit via

According to a third aspect of the present invention, in the first or second aspect of the present invention, the image forming section is configured to be detachable from an image forming apparatus main body.

[0016]

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

FIG. 1 is a sectional view showing the structure of a drive transmitting portion of the image forming apparatus according to the present invention. Although not shown, the image forming section P of the image forming apparatus according to the present invention has a photosensitive drum as a driven member to be rotated. 201, a contact charging device 202, and a developing device 203. As described above, the photosensitive drum 201 as the driven object, the contact charging device 202, and the developing device 203 have different rotation speeds as described above, and are independent of each other because they are not affected by fluctuations in the rotation load of each other. Drive shafts 301, 30 provided at the locations
2 and 303 respectively. With this configuration, the rotation of the photosensitive drum 201 is particularly improved.

A contact charging device 202 and a developing device 203
Couplings 402 and 403 are used for the drive transmission unit to the image forming unit P. When the image forming unit P is formed into a cartridge and is configured to be detachable from the apparatus main body, the image forming unit P is easily attached and detached. It has become so.

A contact charging device 202 and a developing device 203
Electromagnetic clutches 304 and 305 are provided in the middle of the drive path, and drive timings of the contact charging device 202 and the developing device 203 are controlled by the electromagnetic clutches 304 and 305, respectively. For example, at the time of image formation, the photosensitive drum 201, the contact charging device 202, the developing device 203
The rotation is transmitted in this order. This is to ensure that the surface of the photosensitive drum 201 is electrically charged during development, and it is not preferable that the contact charging device 202 and the developing device 203 rotate synchronously. or,
When performing black monochrome printing, the photosensitive drums 2 of other colors (yellow (Y), magenta (M), and cyan (C)) are used.
01 rotates, but the contact charging device 202 and the developing device 203 for the other colors (Y, M, C) are stopped. This is to prevent the deterioration of the developer in the contact charging device 202 and the developing device 203 and extend the life of the cartridge.

As described above, the rotation of the photosensitive drum 201, the contact charging device 202, and the developing device 203 is not performed simultaneously, but the timing of the rotation needs to be controlled separately. Therefore, the electromagnetic clutch 30
The electromagnetic clutches 304 and 305 are arranged not in the cartridge part but in the main body part, and the photosensitive drum 201 and the contact charging device 2 are arranged in the image forming part P.
02. By inputting the driving of the three systems of the developing device 203, the image forming unit P can be configured to be small and inexpensive.

Here, a method of changing the viewpoint and inputting a drive to an image forming section (process cartridge) having three driven sections of a photosensitive drum, a contact charging device, and a developing device will be considered. Specifically, the following five methods are conceivable.

Input at one place, 3
How to branch to the system.

A method of inputting by a photosensitive drum and other two systems.

A method of inputting with a charging device and other two systems.

Input is made to the developing device and the other two systems.

A method of driving three places separately.

Of the above methods, if the photosensitive drum is driven by the same source as the other drives, vibrations and shocks are transmitted to the photosensitive drum.

When the charging device and the developing device are driven by the same input, it is necessary to provide an on / off mechanism such as an electromagnetic clutch inside the cartridge as described above. It is not suitable because it is expensive. Therefore, the above-mentioned problem does not occur in the method of inputting the drive from the three positions, and the method can be said to be very suitable.

By the way, in the above configuration, if the driving sources of the contact charging device 202 and the developing device 203 are made the same, the cost becomes more effective. In this case, only the contact charging device 202 and the developing device 203 use the same drive source.
Since the photosensitive drum 201 is driven separately, there is no adverse effect on its rotation.

In the above embodiment, a charging device employing a contact charging method as a means for charging a photosensitive drum has been described as an example. However, a charging device using a charging roller which needs to be driven may be used. The good thing is, of course.

[0031]

According to the present invention, the image carrier, the charging device, and the developing device as three driven objects provided in the image forming unit are driven independently of each other, so that the size of the image forming unit can be reduced. And cost reduction.

Further, since the driving of the image carrier is separated from the driving of the other charging device and the developing device, vibration and shock are not transmitted from the charging device and the developing device to the image carrier, and a good image quality can be obtained. Can be.

Further, by separately driving the charging device other than the image carrier and the developing device, there is no need to provide a drive separation mechanism in the cartridge, and the size and cost of the cartridge can be reduced. In addition, by independently controlling the drive timing of the charging device and the developing device, the life of the developer can be extended, and the running cost of the device can be reduced because the life of the consumable cartridge is extended.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a drive transmission unit of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a full-color image forming apparatus.

FIG. 3 is a schematic diagram illustrating an image forming unit of the image forming apparatus.

[Explanation of symbols]

 201 Photosensitive drum (image carrier) 202 Charging device 203 Developing device P Image forming unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H003 BB11 CC04 EE16 2H030 AA05 AA07 AB02 AD02 AD17 BB33 2H035 CA07 CB01 CG01 CG03 2H071 BA13 CA01 CA02 CA05 DA06 DA08 DA15 DA26 2H077 BA01 BA09 GA12

Claims (3)

[Claims] 1. A recording medium comprising: a plurality of image forming units each including an image carrier, a charging device that applies electric charges to the image carrier, and a developing device that visualizes a latent image formed on the image carrier. In the image forming apparatus for forming an image on the image forming apparatus, each drive of the image carrier, the charging device, and the developing device in the same image forming unit is input to the image forming unit via different paths. Forming equipment. 2. An image bearing member, comprising: a charging device for applying a charge to the image bearing member by employing a rotating body contact charging method; and a developing device for visualizing a latent image formed on the image bearing member. In an image forming apparatus that includes a plurality of image forming units and forms an image on a recording medium, each drive of the image carrier, the charging device, and the developing device in the same image forming unit is performed via a different path. An image forming apparatus characterized in that the image is input to the image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the image forming section is configured to be detachable from an image forming apparatus main body.