JPH07209947A - Color image forming device - Google Patents

Abstract

PURPOSE:To provide a color image forming device in which the rotation accuracy of a photoreceptor is at a high level and which is provided with an inexpensive photoreceptor driving mechanism. CONSTITUTION:The photoreceptor driving mechanism of the color image forming device where plural photoreceptors 4a, 4b, 4c and 4d are arrayed in the carrying direction of recording paper 2 is constituted of single driving source 14, a gear 15 attached to the rotary shaft of the driving source, direct driving photoreceptor gears 11b and 11c engaged with the gear and provided at the rotary shaft of the direct driving photoreceptors 4b and 4c, idler gears 16 and 17 engaged with the direct driving photoreceptor gear and driven photoreceptor gears 11a and 11d engaged with the idler gear and provided at the rotary shaft of the driven photoreceptors 4a and 4d.

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 a color image forming apparatus using electrophotography such as a color copy, a color facsimile, and a color printer.

[0002]

2. Description of the Related Art As a conventional color image forming apparatus, there is a structure in which a plurality of photoconductors are arranged along the conveying direction of a recording paper. An optical writing device and a different color are provided for each photoconductor. A developing unit that stores toner is provided. Here, in order to prevent color deviation of the color image formed on the recording paper, the accuracy of the diameter of each photoconductor, the position accuracy between the photoconductors, the parallelism accuracy of the writing unit and the photoconductor, and the conveyance In addition to maintaining the high precision of synchronous conveyance between the belt and the photoconductor, the rotation precision of the photoconductor must be high.

Therefore, in a conventional color image forming apparatus in which a plurality of photoconductors are arranged along the direction of conveyance of a recording paper, in order to make the photoconductors have a high rotational accuracy, Japanese Unexamined Patent Publication No. HEI-1 has been proposed.
A drive device using a worm gear as shown in JP-A 6981 or a drive device of a single drive motor type in which a motor is individually provided for each photoconductor has been used.

[0004]

However, although the drive device using the worm gear is excellent in terms of rotational accuracy, it has a large friction coefficient at the meshing tooth surface, so that an expensive oil bath device for oil lubrication is required. It is necessary to provide. Further, since the transmission efficiency of the worm gear is significantly inferior to that of the spur gear or the helical gear, a motor having large torque or horsepower must be used as a drive source. Therefore, the drive source becomes expensive. In addition, even in a drive device of a single drive motor system in which each photoconductor has a motor individually,
Since a plurality of motors are required, the driving device becomes expensive.

The present invention has been made in view of the above points, and an object of the present invention is to provide a color image forming apparatus provided with an inexpensive photoconductor driving mechanism while maintaining a high level of rotation accuracy of the photoconductor. To do.

In order to achieve the above-mentioned object, the invention of claim 1 is a color image forming apparatus in which a plurality of photoconductors are arranged along the conveying direction of a recording paper, and a single image forming apparatus is provided. A drive source, a gear attached to a rotary shaft of the drive source, a first photoconductor gear provided on a rotary shaft of a first photoconductor that meshes with the gear and forms the plurality of photoconductors, A photoconductor including an idler gear that meshes with the first photoconductor gear and a second photoconductor gear that is provided on a rotation shaft of a second photoconductor that forms the plurality of photoconductors that mesh with the idler gear. It is characterized by having a drive mechanism.

According to a second aspect of the present invention, the first photoconductor, the second photoconductor, and the third photoconductor are arranged in this order from the upstream side in the recording paper conveyance direction. And the fourth
A color image forming apparatus having a photoconductor of (1), a single drive source, and a gear attached to a rotation shaft of the drive source;
A second photoconductor gear that is provided on the rotary shaft of the second photoconductor and meshes with the gear, and a third photoconductor gear that is provided on the rotary shaft of the third photoconductor and meshes with the gear. A body gear, a first idler gear that meshes with the second photoconductor gear, a second idler gear that meshes with the third photoconductor gear, and a rotation shaft of the first photoconductor. A first photoconductor gear that meshes with the first idler gear, and a fourth photoconductor gear that is provided on the rotation shaft of the fourth photoconductor and meshes with the second idler gear. It is characterized by having the following photosensitive member drive mechanism.

[0007]

According to the first aspect of the invention, the drive mechanism for the photoconductor can be a spur gear or a helical gear.
Therefore, the oil forced supply device such as the oil bath, which is necessary for the worm gear, becomes unnecessary. Further, since the spur gear and the helical gear have excellent transmission efficiency as compared with the worm gear, the horsepower of the drive motor can be small, so that a small and inexpensive motor can be used.

According to the second aspect of the invention, among the photoconductors arranged along the conveyance direction of the recording paper, the photoconductors located at the ends are directly driven by a motor, and the drive is performed by using an idler gear. It is possible to reduce the accumulation of errors as compared with a drive mechanism that transmits the photoconductor to the body and follows other photoconductors.

【Example】

Hereinafter, a specific description will be given based on an embodiment of the present invention. FIG. 1 is a sectional view showing an embodiment of a color image forming apparatus according to the present invention. Inside the main body 1 of this color image forming apparatus, a paper storage unit 3 for storing the recording paper 2 is provided, and further four photosensitive papers are provided along the conveying direction of the recording paper 2 fed from the paper storage unit 3. Bodies 4a, 4b, 4c,
4d is provided. Here, the photoconductors 4b and 4c correspond to the direct drive photoconductor of claim 1, and the photoconductors 4a and 4d correspond to the driven photoconductor of claim 1. Further, the photosensitive member 4a is the first photosensitive member of claim 2, the photosensitive member 4b is the second photosensitive member of claim 2, the photosensitive member 4c is the third photosensitive member of claim 2, and the photosensitive member 4d. Corresponds to the fourth photoconductor of claim 2.

Around the photoconductors 4a, 4b, 4c and 4d, optical writing devices 5a, 5b, 5c and 5d, developing units 6a, 6b, 6c and 6d, transfer units 7a, 7b and 7 are provided.
c, 7d, etc. are provided. Further, the fixing device 8 is provided behind the photoconductor 4d, which is the final portion along the conveyance direction of the recording paper 2.
Is provided. Here, the developing units 6a to
Toners of different colors are stored in 6d, for example, the developing unit 6a is black, the developing unit 6b is magenta, the developing unit 6c is yellow, and the developing unit 6d is cyan.

FIG. 2 is a plan view showing a drive mechanism for the photoconductors 4a to 4d, which is a main part of the embodiment of the present invention shown in FIG.
3 is a conceptual diagram showing the drive mechanism of the embodiment shown in FIG. The photosensitive members 4a to 4d are held at their ends by a pair of positioning face plates 9a and 9b to fix their relative positions. Further, these positioning face plates 9a and 9b are attached to predetermined positions of the apparatus main body 1 by reference pins 10.

A gear 15 is provided on the rotary shaft of a direct drive motor 14 which is a drive source mounted inside the apparatus main body. The gear 15 meshes with two photoconductor gears, that is, a photoconductor gear 11b attached to the rotary shaft of the photoconductor 4b and a photoconductor gear 11c attached to the rotary shaft of the photoconductor 4c. Therefore, the rotational driving force of the direct drive motor 14 is transmitted to the photoconductor 4b via the gear 15 and the photoconductor gear 11b to rotate the photoconductor 4b. Further, the rotational driving force of the direct drive motor 14 is also transmitted to the photoconductor 4c via the gear 15 and the photoconductor gear 11c, and the photoconductor 4c is rotated.

Further, a first idler gear 16 is provided at a position where it meshes with the photoconductor gear 11b. The idler gear 16 meshes with the photoconductor gear 11a attached to the rotary shaft of the photoconductor 4a. Therefore, the rotational driving force of the direct drive motor 14 is applied to the gear 15 and the photoconductor gear 11
b, transmitted to the photoconductor gear 11a via the idler gear 16, and rotates the photoconductor 4a. A second idler gear 17 is provided at a position where it meshes with the photoconductor gear 11c. This idler gear 17 is provided on the photoconductor 4d.
Meshes with the photoconductor gear 11d attached to the rotating shaft. Therefore, the rotational driving force of the direct drive motor 14 is transmitted to the photoconductor gear 11d via the gear 15, the photoconductor gear 11c, and the idler gear 17 to rotate the photoconductor 4d.

In the above description, the photoconductor gear 11
b and the photoconductor gear 11c correspond to the direct drive photoconductor gear of claim 1, and the photoconductor gear 11a and the photoconductor gear 11d correspond to the driven photoconductor gear of claim 1. Also, the photoconductor gear 1
1a corresponds to the first photoconductor gear of claim 2, the photoconductor gear 11b corresponds to the second photoconductor gear of claim 2, and the photoconductor gear 11c corresponds to the third photoconductor gear of claim 2. Is equivalent to
The photoconductor gear 11d corresponds to the fourth photoconductor gear of claim 2.

[0015]

According to the present invention, the drive mechanism of the photoconductor can be constituted by a spur gear or a helical gear. Therefore, the oil forced supply device such as the oil bath, which is necessary for the worm gear, becomes unnecessary. Further, since the spur gear and the helical gear have excellent transmission efficiency as compared with the worm gear, the horsepower of the drive motor can be small, so that a small and inexpensive motor can be used.

Further, according to the present invention, a split drive system is adopted in which two gears, that is, a second photoconductor gear and a third photoconductor gear are meshed with a gear attached to the rotary shaft of the drive source.
Therefore, among the photoconductors arranged along the conveyance direction of the recording paper, the photoconductors located at the ends are directly driven by the motor, and the drive is transmitted to the other photoconductors by using the idler gear, and the other photoconductors are exposed. It is possible to reduce the accumulation of errors as compared with a drive mechanism that follows the body.

[0017]

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a front view showing a main part of the embodiment shown in FIG.

FIG. 3 is a conceptual diagram showing a main part of the embodiment shown in FIG.

[Explanation of symbols]

 1 image forming apparatus main body 2 recording paper 3 paper storage unit 4a, 4b, 4c, 4d photoconductors 5a, 5b, 5c, 5d optical writing unit 6a, 6b, 6c, 6d developing unit 7a, 7b, 7c, 7d transfer unit 8 Fixing unit 9a, 9b Positioning face plate 10 Reference pin 11a, 11b, 11c, 11d Photoreceptor gear 14 Direct drive motor 15 Gear 16 First idler gear 17 Second idler gear

Claims (2)

[Claims] 1. A color image forming apparatus in which a plurality of photoconductors are arrayed along a conveyance direction of a recording paper, wherein a single drive source, a gear attached to a rotation shaft of the drive source, and the gear. A direct drive photoconductor gear provided on a rotary shaft of a direct drive photoconductor that meshes with the plurality of photoconductors, an idler gear that meshes with the direct drive photoconductor gear, and a plurality of the plurality of gears that mesh with the idler gear. A color image forming apparatus comprising: a photosensitive member driving mechanism including a driven photosensitive member gear provided on a rotation shaft of a driven photosensitive member that forms a photosensitive member. 2. A first photoconductor, a second photoconductor, a third photoconductor, and a fourth photoconductor, which are arranged in order from the upstream side in the recording paper transport direction along the recording paper transport direction. A color image forming apparatus having: a single drive source; a gear attached to a rotation shaft of the drive source; and a gear provided on a rotation shaft of the second photoconductor and meshing with the gear. A second photoconductor gear, a third photoconductor gear that is provided on the rotation shaft of the third photoconductor and meshes with the gear, and a first idler gear that meshes with the second photoconductor gear. A second idler gear that meshes with the third photoconductor gear, and the first idler gear
First photoconductor gear that is provided on the rotation shaft of the photoconductor and meshes with the first idler gear, and meshes with the second idler gear that is provided on the rotation shaft of the fourth photoconductor. A color image forming apparatus having a photosensitive member driving mechanism including a fourth photosensitive member gear.