JPH08312727A - Driving device of image forming device - Google Patents

Abstract

PURPOSE: To improve matching to a driving system on a latent image writing side, so as to obtain a high-quality image by arranging internal gears on all driving force transmitting parts of a gear train. CONSTITUTION: Driving force of a main motor 3 is transmitted from a pinion gear 4 to a gear 81 and an internal gear 51, and driving force transmitted to the gear 81 drives a paper sheet feeding unit and a fixing unit via a gear train. Driving force transmitted to the internal gear 51 drives an internal gear 56 via gears 52, 53, an internal gear 54 and a gear 55, and a gear 71 coaxial to a transfer roller on a cartridge 7 side is meshed with the internal gear 56. A long bearing 61 is provided between two frames 1a, 1b, so as to support a shaft 63, the oscillation of the shaft 63, causing dispersion of a central distance is avoided, and deformation in the longitudinal direction on the thrust surface of the gear is regulated. Since meshing of the teeth are gradually approached or separated, shock in meshing is small, moreover, since the number of teeth of gears to be meshed at once is large, abrasion is small and unevenness of the rotation can be maintained small.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus utilizing an electrostatic transfer process such as an electrostatic copying machine and a printer, and more particularly to a drive transmission device thereof.

[0002]

2. Description of the Related Art A typical example of the drive transmission means of the known image forming apparatus as described above will be briefly described with reference to FIG.

Reference numeral 1 in FIG. 1 is a frame of the image forming apparatus.
A cartridge 7 including an image carrier, a developing device, a transfer roller, a cleaner, etc. is detachably mounted on the main body. When the cartridge is mounted and an image forming operation is executed, a partition indicated by reference numeral 2 is provided. The floor surface also serves as the transfer material transport path.

Reference numeral 3 in the drawing denotes a transfer material supply device, a fixing device,
The main motor that drives the image carrier of the cartridge, the transfer roller, and the like, and the gear 4 fixed to the shaft is the gear 51,
81 shall be driven (each gear shall be represented by a pitch circle-same below).

The driving force transmitted to the gear 51 is a double gear 52 having a pinion coaxially, a gear 53, and a double gear 5.
4 drives the gear 55, and when the cartridge 7 is mounted, the gear 55 engages with the gear 71 which drives the transfer roller.

A gear 61 meshing with the gear 51 drives a fixing device (not shown) via gear trains 62, 63, 64 and the like.

The driving force transmitted from the gear 4 to the gear 81 drives a paper feeding unit which supplies a transfer material to a transfer portion via a gear train (not shown).

A latent image is written on an image carrier (not shown) by an optical means by a drive system different from the above drive system. Therefore, the pitch in the sub-scanning direction of the optical means on the latent image writing side, that is, the traveling direction of the transfer material and the traveling speed of the image carrier are as closely as possible, or the phase and direction of the speed fluctuation are the same. Is an essential requirement for obtaining good quality images.

However, it must be said that the latter means is difficult to implement because the control becomes complicated. In general, as described above, when the driving force is transmitted in such a relationship that the pitch circles of each gear are circumscribed, it is caused by a tooth profile error, a tooth deflection, an error in the distance between the centers, etc. It is unavoidable that unevenness in rotation occurs due to deviation from rolling contact, backlash, etc., which causes deterioration in image quality.

In the case of an ideal involute gear, it is performed by rolling contact on the meshing pitch circle of each tooth. However, in reality, such a thing is difficult because of the above-mentioned causes. The engagement mode when the state is out of the state will be briefly described with reference to FIGS. 6 to 8.

As shown in FIG. 6, from the state where the root of the drive gear 1 and the end of the gear of the driven gear 2 are in contact with each other at a point A,
Both gears rotate so that both teeth are in contact with each other on the pitch circle B as shown in "Fig. 7". Further, as shown in "Fig. 8", the end of gear 1 and the root of gear 2 are added. Are in contact with each other at point C.

Therefore, the ratio of the rotational speeds of both gears is calculated from "the distance from the center of the driving gear 1 to the point A" to "the distance from the center of the driven gear 2 to the point A" (in the case of "FIG. 6"). , "Distance from the center of the driving gear 1 to the point C" vs. "distance from the center of the driven gear 2 to the point C" (in the case of "Fig. 8"), which results in uneven speed. Will be deteriorated.

The present invention has been made to cope with the above situation, and in the drive system of the image forming apparatus shown in FIG. 5, an internal gear is used as a gear forming a gear train. By doing so, the irregular transmission of the driving force due to the tooth profile error, the error of the axial distance, etc. can be minimized, and the matching with the drive system on the latent image writing side can be improved to obtain a high quality image. An object of the present invention is to provide a driving force transmission device for an image forming apparatus.

[0014]

Configuration of the Invention

In order to achieve the above object, the present invention provides a driving device for an image forming apparatus configured to transmit a driving force from a driving source to a transfer roller by a gear train. It is characterized in that internal gears are arranged at all of the driving force transmitting portions of the gear train.

With this structure, it is possible to minimize uneven rotation of the transfer means such as the transfer roller which is the final driven portion.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [FIG. 1] FIG. 1 is a perspective view of an essential part showing a drive system of an image forming apparatus showing an embodiment of the present invention, in which two frames are provided to stably support a rotating shaft. 2 is a thin plate 1a, 1b, and 2 is a partition floor surface forming a part of the main body, which is a transfer material guide surface, and the transfer material is conveyed in the direction of the outlined arrow in the figure.

The driving force of the main motor 3 is transmitted from the pinion 4 attached to the motor to the gear 81 and the internal gear 51, and the driving force transmitted to the gear 81 passes through a gear train (not shown) to a sheet feeding unit, Drive the fusing unit.

The driving force transmitted to the internal gear 51 drives the internal gear 56 through the gears 52, 53, the internal gear 54, and the gear 55, and the transfer roller (not shown) on the cartridge 7 side.
It is assumed that a gear 71 coaxial with the gear meshes with the internal gear 56.

FIG. 2 shows the internal gear 56 in the gear train and a gear 71 arranged on the drive shaft of the transfer roller.
In the end view of the essential part showing the engagement between and, the cartridge 7 supporting the transfer roller is first inserted in the internal gear 56 from the direction of arrow a, and then moved in the direction of arrow b to move the gear 71 to internal teeth. The gear 56 shall be engaged.

In the case of the illustrated apparatus, the tooth width of the gears 52, 53, 55 is secured by setting the module to 0.4, and the entire gear is made of polyacetal as the main material and having a good slidability.

When the internal gear is used as described above,
As shown in FIG. 3, for example, a gear shaft for connecting the internal gears, that is, a shaft 63 as shown by the reference numeral 63 in FIG. 3 is required. If it is not regulated inside, the meshing may become too shallow and the center-to-center distance may vary. Therefore, as shown in the figure, the shaft 63 connecting the two gears is provided with the long bearing 61 between the two frames 1a and 1b.
This prevents the shaft 63 from swinging, which causes the center-to-center distance to vary, and the thrust surface of the gear regulates the displacement in the longitudinal direction.

As described above, the use of the internal gear for the gears forming the gear train causes the meshing of the teeth to gradually approach or move away from each other, so that the impact at the time of squeeze is small and the number of teeth of the squealing gears is large. Therefore, tooth deflection and wear are small, and the rotation unevenness of the driven part is kept small, so that a stable transmission system can be obtained for a long period of time.

Further, the module is made as small as possible,
By shortening the tooth height, it is possible to minimize the fluctuation of the rotational speed as described above due to the movement of the meshing points between the teeth. This can be achieved by increasing the difference between the outer shape of the gear and the height of the teeth, but in reality,
Since it is impossible to increase the outer diameter of the gear unnecessarily due to the space limitation of the image forming apparatus itself, it is preferable to reduce the module size, and it is preferable to set the value to 3 or less. Since the meshing ratio increases by using gears, if the conditions of tooth width and transmission torque are the same, the module can be made smaller with gears of the same strength.

As described above, since the gear forming the driving force transmission system from the drive source to the transfer roller in the image forming apparatus is constituted by the internal gear, the gear train construction is not caused and the cost is not increased. The rotation unevenness of the transfer roller can be minimized, and synchronization with the drive system on the image writing side can be easily achieved.

FIG. 4 shows another embodiment of the present invention. FIG. 4 shows only a portion of the gear train for transmitting the driving force from the internal gear to another internal gear. The overall structure of the forming apparatus and its drive transmission system is the same as that of the above-described embodiment.

In the case shown in the figure, the frame is composed of one piece, and the gears 64 and 65 are attached to the shaft 63 supported by the frame.
Are attached, and these gears are the internal gear 69,
It meshes with 68. Thrust play in the longitudinal direction of the shaft 63 is regulated by the thrust surfaces of both gears 64 and 65, each gear 64 meshes with a gear 67 concentric with the internal gear 69, and the gear 65 is attached to the frame. It meshes with 66. This structure prevents the shaft 63 from swinging.

In the above case, the gear 65 meshes with the gear 66 attached to the frame. However, since this has a large diameter of the internal gear 68, it is of course necessary to use the gear 64 and the gear 64 together. It is also possible to adopt a structure similar to the relationship with the gear 67.

It can be easily understood that even with such a structure, the deflection of the shaft 63 can be prevented and the same operation as that of the above-described embodiment can be achieved.

[0029]

As described above, according to the present invention, in an image forming apparatus that uses a gear train to transmit a driving force from a driving source to a transfer unit, a singing place gear is used for each gear and a module is used. It is possible to minimize the occurrence of rotation unevenness due to tooth profile error, center distance error tooth deformation, etc. and deterioration of image quality due to this by setting the number to 3 or less. Since the change in gear diameter can be suppressed even if the number is changed, it is easy to obtain the desired speed ratio without considering the space, and there is no need for a special accessory mechanism. Is also extremely effective.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a drive system of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is an end view of a main part of the same apparatus showing a means for mounting a transfer roller on a main body.

FIG. 3 is an end view showing a connecting means between internal gears in the compassion device.

FIG. 4 is an end view showing another embodiment showing a connection mode between internal gears.

FIG. 5 is a perspective view of a main portion showing a drive system portion of a known image forming apparatus.

[Figure 6]

[Figure 7]

FIG. 8 is an explanatory diagram showing a mode in which irregular transmission occurs when driving force is transmitted by a gear.

[Explanation of symbols]

 1 frame 2 partition surface for transfer material conveyance guide 3 drive motor 4 common pinion 51, 54, 56 internal gear 52, 53, 55, 81 gear

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[Procedure amendment]

[Submission date] June 19, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

A latent image is written on an image carrier (not shown) by an optical means by a drive system different from the above drive system. Therefore, the pitch in the sub-scanning direction of the optical means on the latent image writing side, that is, the traveling direction of the transfer material, and the traveling speed of the image carrier are kept as strictly as possible, or the phase and direction of the speed fluctuation are the same. Doing is an essential requirement for obtaining good quality images.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

In the case of an ideal involute gear, the meshing of the teeth is carried out so as to transmit the rotational motion at a constant speed at a constant speed. In reality, however, such a thing is caused by the above reasons. The engagement state when it is difficult and deviated from the ideal state will be briefly described with reference to FIGS. 6 to 8.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

Configuration of the Invention

In order to achieve the above-mentioned object, the present invention provides a drive unit for an image forming apparatus configured to transmit a driving force from a drive source to a photosensitive drum by a gear train. The internal gears are arranged at all the driving force transmitting portions of the above.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

With this configuration, it is possible to minimize uneven rotation of the photosensitive drum, which is the final driven portion, due to transfer failure.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

As described above, according to the present invention, in the image forming apparatus utilizing the gear train for transmitting the driving force from the driving source to the transfer means, the internal gear is used for each gear, and the module is suitable. By setting 3 to 3 or less, it is possible to minimize tooth profile error, center distance error, rotation unevenness due to tooth deformation, etc., and deterioration of image quality due to this, and decelerate using the gear train. Even in such a case, it can be accommodated in a relatively small space and does not require a special auxiliary mechanism, which is advantageous in terms of cost.

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

[Procedure Amendment 8]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5] ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 5, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a drive system of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is an end view of a main part of the same apparatus showing a means for mounting a transfer roller on a main body.

FIG. 3 is an end view showing a connecting means between internal gears in the compassion device.

FIG. 4 is an end view showing another embodiment showing a connection mode between internal gears.

FIG. 5 is a perspective view of a main portion showing a drive system portion of a known image forming apparatus.

FIG. 6 is an explanatory view showing a mode in which irregular transmission occurs when driving force is transmitted by a gear.

FIG. 7 is an explanatory view showing a mode in which irregular transmission occurs when driving force is transmitted by a gear.

FIG. 8 is an explanatory diagram showing a mode in which irregular transmission occurs when driving force is transmitted by a gear.

[Explanation of Codes] 1 Frame 2 Partition Surface for Transfer Material Transfer Guide 3 Drive Motor 4 Pinion 51, 54, 56 for Same Drive Internal Gear 52, 53, 55, 81 Gear

Claims (4)

[Claims] 1. A driving device of an image forming apparatus configured to transmit a driving force from a driving source to a transfer roller by a gear train, wherein an image is formed by arranging internal gears at all driving force transmitting portions of the gear train. Forming device drive. 2. The drive unit according to claim 1, wherein the number of gear modules constituting the gear train is 3 or less. 3. The drive device according to claim 1, wherein the rotary shaft or the bearing thereof in the gear train is supported by a plurality of frame members. 4. A gear train mounted on a rotary shaft of a gear train, wherein a gear for preventing the blurring is meshed with the gear. The drive device described.