KR101191900B1 - Image forming apparatus - Google Patents

Abstract

An image forming apparatus according to the present invention includes an image forming unit having a rotatable photosensitive medium; A transfer unit having a transfer belt external to the photosensitive medium; A drive unit having a photosensitive medium drive gear for rotating the photosensitive medium and a transfer belt drive gear for rotating the transfer belt; A load applying member that applies a predetermined load to the photosensitive medium drive gear; And a load adjusting unit for adjusting a load applied to the photosensitive medium driving gear. According to this, the driving force of a constant speed is transmitted to the photosensitive medium, and a stable image can be obtained.

Burn, constant speed, felt, drive, gear, teeth, wear, jitter, speed deviation, vibration.

Description

[0001] IMAGE FORMING APPARATUS [0002]

1 is a configuration diagram schematically showing a general image forming apparatus;

2 is a configuration diagram schematically showing an image forming apparatus according to an embodiment of the present invention, and

3 is a cross-sectional view showing the structure and operation of a load adjusting unit which is a main part of the image forming apparatus shown in FIG.

Description of the Related Art

110: image forming unit 111: photosensitive medium

111a: Photosensitive gear 112: Developing unit

113: exposure unit 120: transfer unit

121: transfer belt 122: transfer roller

130: drive unit 131: motor

132: second gear 133: first power transmission gear

134: second power transmission gear 135: photosensitive medium drive gear

136: transfer belt drive gear 140: load application member

141: felt 142: felt high government

150: load control unit 151: elastic member

152: nut

The present invention relates to an image forming apparatus such as a printer, a copier and a multifunction printer.

In general, an image forming apparatus includes a photosensitive medium on which a predetermined electrostatic latent image is formed, a developing unit for developing an electrostatic latent image of the photosensitive medium, and a transfer unit for receiving the developed image and transferring it to a print medium. Here, the photosensitive medium and the transfer unit are generally driven by receiving driving force from one driving motor.

1 schematically shows an example of such an image forming apparatus. In the drawings, reference numeral 1 is a photosensitive medium, 2 is an exposure unit, 3 is a developing unit, 4 is a transfer unit, and 10 is a driving device.

The surface of the photosensitive medium 1 is exposed by the exposure unit 2 to form an electrostatic latent image, and the electrostatic latent image is developed by the developing unit 3. The transfer unit 4 includes a plurality of transfer rollers 4a and a transfer belt 4b supported by the transfer rollers 4a so as to be capable of traveling, so that images of each color on the photosensitive medium 1 are superimposed. It is transferred to the print media.

The driving device 10 transmits the driving force of the motor 11 to the photosensitive medium 1 and the transfer unit 4 by a plurality of gears.

More specifically, the driving force of the drive motor 11 is transmitted to the first power transmission gear 14 through the drive gear 12, and is transmitted to the transfer gear 13 through the first power transmission gear 14. do. As a result, the transfer belt 5b is driven.

In addition, the driving force transmitted to the transfer gear 13 is transmitted to the photosensitive gear 16 through the second power transmission gear 15 and the third power transmission gear 17. Thus, the photosensitive medium 1 is driven to rotate.

On the other hand, the power transmission by the drive device 10 as described above is transmitted to the engagement of the teeth corresponding to less than 10% of the total teeth of each gear. As a result, the entire load of the gear acts as a concentrated load on several teeth engaged with each other, causing tooth wear and deformation, thereby causing a speed change, vibration, and noise.

Tooth wear and deformation, such as backlash caused by the above-described fine vibration of the photosensitive medium 1, the photosensitive medium 1 also undergoes a speed change by the high-speed rotation of the developing unit (3). These hinder the constant-speed running of the photosensitive medium 1, and also cause jitter phenomena, which may cause deterioration of image quality.

The present invention has been made in view of the above, and an object thereof is to provide an image forming apparatus capable of obtaining a stable image by inducing constant speed travel of a photosensitive medium.

An image forming apparatus according to the present invention for achieving the above object, the image forming unit having a rotatable photosensitive medium; A transfer unit having a transfer belt circumscribed with the photosensitive medium; A drive unit having a photosensitive medium drive gear for rotating the photosensitive medium and a transfer belt drive gear for rotating the transfer belt; A load applying member that applies a predetermined load to the photosensitive medium drive gear; And a load adjusting unit for adjusting a load applied to the photosensitive medium driving gear.

According to a preferred embodiment of the present invention, the load applying member includes a felt in friction contact with one side of the photosensitive medium drive gear and a felt fixing part which supports the felt and is installed on the axis of the photosensitive medium drive gear, The load adjusting unit may include an elastic member for pressing the friction member toward the photosensitive medium driving gear; And a nut fastened to the photosensitive medium drive gear shaft to adjust the elastic force of the elastic member.

Here, the photosensitive medium drive gear is preferably formed with an uneven portion for increasing the contact area with the felt.

Here, the felt may have a thickness of about 0.5 ~ 3mm.

In addition, the drive unit, a motor that is a drive source; A second gear having a first gear meshing with a gear coupled to the shaft of the motor and a second gear coaxially coupled with the first gear; And first and second power transmission gears interposed between the second gear of the second gear and the photosensitive medium drive gear and the transfer belt drive gear, respectively.

Hereinafter, an image forming apparatus according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in Figure 2, the image forming apparatus according to an embodiment of the present invention, the image forming unit 110, the transfer unit 120, the drive unit 130, the load applying member 140 and the load adjusting unit ( 150).

The image forming unit 110 includes a photosensitive medium 111, an exposure unit 112, and a developing unit 113 to form a predetermined image on a print medium.

The photosensitive medium 111 has a drum shape and is rotatably installed at a predetermined speed inside a frame (not shown). Here, the photosensitive medium 111 is provided with a photosensitive gear 111a coaxially installed, and is rotated by receiving a driving force from the driving unit 130.

The exposure unit 112 exposes the surface of the photosensitive medium 111 to form a predetermined electrostatic latent image corresponding to desired image data.

The developing unit 113 is provided in plural in correspondence with each color developer to be built therein to develop an electrostatic latent image formed on the surface of the photosensitive medium 111. The developing unit 113 includes a developing roller 113a for developing the electrostatic latent image of the photosensitive medium 111 with a built-in developer and a supply roller 113b for supplying the developer to the developing roller 113a.

Since the image forming unit 110 having the above configuration can be understood from a known technique, detailed description thereof will be omitted.

The transfer unit 120 is to transfer the image developed on the surface of the photosensitive medium 111 to be superimposed and transferred to the print medium, and includes a transfer belt 121 and a transfer roller 122.

The transfer belt 121 is supported by a plurality of transfer rollers 122 provided, and runs externally with the photosensitive medium 111. Here, the transfer roller 122 receives the driving force from the drive unit 130 to drive the transfer belt 121.

The driving unit 130 simultaneously transmits a driving force to the photosensitive medium 111 and the transfer belt 121, for this purpose, the motor 131, the second gear 132, the first and second power transmission gear ( 133, 134, a photosensitive medium driving gear 135, and a transfer belt driving gear 136.

The motor 131 is a driving source providing a driving force to the photosensitive medium 111 and the transfer belt 121. Here, the motor 131 is coupled to the shaft, has a motor gear 131a that rotates together.

The second gear 132 is engaged with the motor gear 131a and the first gear 132a receiving the driving force of the motor 131 and the second gear 132b coupled to the shaft of the first gear 132a. ) That is, the second gear 132 is rotated in the same rotation direction by the first and second gears (132a, 132b) share the axis.

The first and second power transmission gears 133 and 134 mesh with the second gear 132b of the second gear 132. In addition, the first and second power transmission gears 133 and 134 are meshed with the photosensitive medium drive gear 135 and the transfer belt drive gear 136, respectively.

That is, the first power transmission gear 133 is interposed between the second gear 132b and the photosensitive medium drive gear 135, and the second power transmission gear 134 is the second gear 132b and the transfer belt. Interposed between the drive gear 136.

Here, the photosensitive medium driving gear 135 is a gear meshed with the photosensitive gear 111a provided coaxially with the photosensitive medium 111. In addition, the transfer belt drive gear 136 is a gear coupled to the shaft of any one of the transfer roller 122 of the plurality of transfer roller 122 to support the transfer belt 121 to run.

The load applying member 140 applies a predetermined load to the photosensitive medium driving gear 135 and, as shown in FIG. 3, includes a felt 141 and a felt fixing part 142.

 One surface of the felt 141 is in contact with one side of the photosensitive medium driving gear 135 to generate a friction force. The felt 141 is a material capable of minimizing noise and wear with the contacting member. In this case, the felt 141 may have a thickness of 0.5 to 3 mm in order to generate an appropriate friction force in close contact with the rotating photosensitive medium driving gear 135.

On the other hand, one side of the photosensitive medium drive gear 135 in contact with the felt 141 is provided with an uneven portion 135b, it is preferable to widen the contact area between the felt 141 and the photosensitive medium drive gear 135. Do.

The felt fixing part 142 is bonded to the other surface of the felt 141 that does not contact the photosensitive medium driving gear 135. At this time, the felt fixing part 142 is bonded to the felt 141 by an adhesive means such as a double-sided tape. Accordingly, the felt fixing part 142 allows the felt 141 and the photosensitive medium driving gear 135 to be in close contact with each other.

In the present embodiment, the load applying member 140 is illustrated as including the felt 141, but is not necessarily limited thereto. That is, when the load applying member 140 is in contact with the photosensitive medium drive gear 135, it is natural that the load applying member 140 may be formed of a rubber-like material that can suppress the noise and wear that may occur.

The load adjusting unit 150 is for adjusting the load applied to the photosensitive medium drive gear 135 by the load applying member 140, as shown in Figure 3, the elastic member 151 and the nut 152.

The elastic member 151 presses the load applying member 140 toward the photosensitive medium driving gear 135. More specifically, the elastic member 151 presses the felt fixing part 142 of the load applying member 140 in the A direction to bring the felt 141 into close contact with one side of the photosensitive medium driving gear 135.

The nut 152 is fastened to the axis of the photosensitive medium drive gear 135 to adjust the elastic force of the elastic member 151. Specifically, by adjusting the elastic force of the elastic member 151 while the nut 152 moves along the axis 135a of the photosensitive medium drive gear 135, the photosensitive medium drive gear 135 and the load applying member 140. Adjust the adhesion between.

An operation relationship of the image forming apparatus according to the embodiment of the present invention having the above configuration will be described with reference to FIGS. 2 and 3.

When the print signal is input, the motor 131 is driven. The driving force of the motor 131 is transmitted to the second gear 132 meshed with the motor gear 131a. Here, the driving force of the motor 131 is decelerated to the first stage through the first gear 132a of the motor gear 131a and the second gear 132, and the first gear 132a and the second gear 132b. Deceleration to 2nd stage through.

Thereafter, the second gear 132b simultaneously branches the driving force reduced in two stages and transmits the driving force to the first and second power transmission gears 133 and 134. The first and second power transmission gears 133 and 134 transfer the branched driving force to the photosensitive medium drive gear 135 and the transfer belt drive gear 136, respectively.

Thereafter, the photosensitive medium driving gear 135 drives the engaged photosensitive gear 111a to rotate the photosensitive medium 111, and the transfer belt driving gear 136 drives the coaxially mounted transfer roller 122. Rotate the transfer belt 121.

As such, the driving force of the motor 131 is simultaneously branched by the second gear 132 to be simultaneously transmitted to the photosensitive medium 111 and the transfer belt 121, thereby minimizing the number of gears that transmit the driving force. The rotation ratio of the medium 111 and the transfer belt 121 can be adjusted by an integral multiple. Accordingly, the image for each color developed on the surface of the photosensitive medium 111 may be superimposed and transferred to the transfer belt 121 by sequentially correcting the phases.

A predetermined load is applied to the photosensitive medium driving gear 135 by the frictional force of the felt 141 installed in close contact with one side when rotating by the transmitted driving force. As a result, speed changes, vibrations, and noises that may be generated due to disturbance or torque change during driving of the photosensitive medium driving gear 135 are mostly absorbed by the felt 141, so that the constant speed driving of the photosensitive medium 111 is performed. Can be derived.

On the other hand, the friction force between the photosensitive medium drive gear 135 and the load applying member 140 is adjustable by the elastic member 151 and the nut 152 for adjusting the elastic force of the elastic member 151. In this way, the load applied to the photosensitive medium drive gear 135 can be adjusted appropriately, so that the factor that hinders the constant speed travel of the photosensitive medium 111 can be more effectively absorbed.

According to the image forming apparatus of the present invention as described above, by applying an adjustable load to the photosensitive medium drive gear for transmitting the driving force to the photosensitive medium, disturbance or toggling changes that may occur during the driving of the gears for driving the photosensitive medium It can absorb the speed change, vibration and noise caused by it.

In addition, since the driving force of the motor is simultaneously branched and transferred to the photosensitive medium and the transfer belt, respectively, the image for each color developed on the photosensitive medium can be sequentially transferred with the correct phase by the transfer belt.

Thus, by providing a stable driving force to the photosensitive medium to induce constant speed travel, it is possible to implement a stable image.

While the invention has been shown and described in connection with the preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. And all such modifications and changes as fall within the scope of the present invention are therefore to be regarded as being within the scope of the present invention.

Claims (5)

An image forming unit having a rotatable photosensitive medium; A transfer unit having a transfer belt external to the photosensitive medium; A drive unit having a photosensitive medium drive gear for rotating the photosensitive medium and a transfer belt drive gear for rotating the transfer belt; A load applying member that applies a predetermined load to the photosensitive medium drive gear; And And a load adjusting unit for adjusting a load applied to the photosensitive medium driving gear. The load applying member includes a felt in friction contact with one side surface of the photosensitive medium drive gear and a felt fixing part which supports the felt and is installed on the shaft of the photosensitive medium drive gear, And the uneven portion is formed in the photosensitive medium driving gear to increase the contact area with the felt. The method of claim 1, The load control unit, An elastic member for pressing the load applying member toward the photosensitive medium driving gear; And And a nut fastened to the photosensitive medium drive gear shaft to adjust the elastic force of the elastic member. delete The method of claim 1, The felt is an image forming apparatus, characterized in that having a thickness of about 0.5 ~ 3mm. The method of claim 1, wherein the drive unit, A motor which is a driving source; A second gear having a first gear meshing with a gear coupled to the shaft of the motor and a second gear coaxially coupled with the first gear; And And first and second power transmission gears interposed between the second gear of the second gear, the photosensitive medium drive gear, and the transfer belt drive gear, respectively.

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