JP2001318495A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a developing roller and a photoreceptor roller by a single motor. SOLUTION: The device is composed the shared motor 37, a photoreceptor motor pulley 34B and a developer motor gear 32 which are fixed to the rotary shaft of the shared motor 37, a reduction pulley 38B on which a belt 39A is stretched so as to be laid between the photoreceptor motor pulley 34B and the pulley 38B, a photoreceptor roller driving pulley 36B which is attached to a 2nd plate 30A and on which the belt 39B is stretched so as to be laid between the reduction pulley 38B and the pulley 36B, and also, to which the photoreceptor roller 7 is connected, and for rotating the photoreceptor roller 7 by the rotating force of the shared motor 37 transmitted from the photoreceptor motor pulley 34B, and a developing roller driving gear 33 which is attached to a 1st plate 30B and which is engaged with a developing motor gear 32, and also, to which the developing roller 11 is connected, and for rotating the developing roller 11 by the rotating force of the shared motor 37 transmitted from the developing motor gear 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic system.

[0002]

2. Description of the Related Art Conventionally, a photoreceptor roller as an image carrier and a developing roller for developing an electrostatic latent image formed on the photoreceptor roller are formed by electrophotographic technology such as a printer, a facsimile, and a copying machine. It is used in an image forming unit of an image forming apparatus. Here, accurate color superposition of the toner images of each color is required for color print output, and in order to obtain a stable image, the photoconductor roller and the developing roller are so fixed that there is no speed fluctuation such as rotation unevenness. It is important to accurately drive and not to use complicated mechanisms.

[0005] Next, a description will be given of a conventional drive transmission technique for the photosensitive roller and the developing roller.

FIG. 5 is a perspective view showing a main part of a power transmission mechanism in a conventional photosensitive roller and developing roller.
FIG. 4 is a front view showing a main part of a power transmission mechanism in a conventional photosensitive roller and a developing roller.

A power transmission means is provided by a photoconductor driving motor 28 called a photoconductor roller driving system, and a photoconductor roller (second
Of the drive transmission means using several drive transmission means such as gears and pulleys, and a developing roller drive motor 29 called a developing roller drive system to a developing roller (first roller) 11. It consists of two drive trains arranged in a row of drive transmission means.

As shown, a photosensitive member drive motor 28 and a developing roller drive motor 29 are attached to a plate 27. The rotation axis of the photoconductor drive motor 28 is the plate 2
7, a photoreceptor motor gear 34A is fixed to the tip of the hole. Plate 2
A photoreceptor drive gear 36A is rotatably attached to 7. Further, an intermediate gear 35A is rotatably attached to the plate 27 so as to mesh with the photoconductor motor gear 34A and the photoconductor drive gear 36A. The photoconductor roller 7 on which the electrostatic latent image is formed is connected to the photoconductor drive gear 36A via a transmission connection device (not shown).

The rotating shaft of the developing roller drive motor 29 passes through a hole formed in the plate 27, and a developing motor gear 32 is fixed to the end of the hole. A developing roller drive gear 33 is rotatably attached to the plate 27. Further, an intermediate gear 35B is rotatably attached to the plate 27 so as to mesh with the developing motor gear 32 and the developing roller driving gear 33. The developing roller 11 for visualizing the electrostatic latent image formed on the photosensitive roller 7 is provided with a transmission connection device (not shown).
The developing roller driving gear 33 is connected via

Here, the outer diameters of the photosensitive roller 7 and the developing roller 11 are reduced in order to reduce the size of the image forming apparatus.
A is also reduced in diameter.

[0009]

However, in the above-mentioned prior art, there is a limit in compactly arranging two drive systems on the same plane, and a gear is provided on a rotating gear. The drive system for the photosensitive roller and the drive system for the developing roller are separately driven by high-cost motors 28 and 29 because, for example, a shaft to be supported cannot be arranged.

At this time, since it is necessary to prevent the two motor mounting positions from interfering with each other, each drive system is arranged at the shortest position for transmitting the driving force from the motor shaft to each of the rollers 7 and 11. Therefore, it is necessary to use the intermediate gears 35A and 35B, which are likely to cause rotation unevenness, to bypass the rotation.

As described above, in the conventional image forming apparatus, it is necessary to provide the motor 28 for driving the photosensitive roller 7 and the motor 29 for driving the developing roller 11, thereby increasing the cost.

Also, as described above, the two motors 28, 29
Are mounted so that they do not interfere with each other,
Since each of the developing rollers 11 has to be driven, it is necessary to use the intermediate gears 35A and 35B which tend to cause uneven rotation and deteriorate space efficiency.

Conventionally, the positioning of the process unit for forming a toner image and the apparatus main body is performed by connecting the photosensitive member driving gear 36A from the axial direction in order to reduce drive rotation unevenness. The shaft of the gear 36A has a cantilever configuration. Therefore, the photoconductor drive gear 36A
The weight of the process unit and the torque at the time of driving are applied to the rotating shaft, and the run-out of the rotating shaft is one of the causes of the drive rotation unevenness. Here, as measures to prevent the rotation of the rotating shaft of the photoconductor driving gear 36A, the rigidity of the plate 27 (e.g., increasing the thickness), the rotation shaft of the photoconductor driving gear 36A and the plate 2 are increased.
7, it is necessary to increase the fixing strength with respect to 7 and to obtain the accuracy of the axial position of the photoconductor driving gear 36A, which has increased the cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of driving a developing roller and a photosensitive roller by a single motor.

Another object of the present invention is to provide an image forming apparatus capable of driving two rollers, a developing roller and a photosensitive roller, without using an intermediate gear.

It is another object of the present invention to provide an image forming apparatus capable of preventing a rotation of a rotation axis of a drive system.

[0017]

In order to solve this problem, an image forming apparatus according to the present invention comprises: a motor attached to a first plate for generating a rotational force; a motor pulley fixed to a rotating shaft of the motor. And a motor belt fixed to the rotating shaft of the motor, and a second plate fixedly arranged in parallel with the first plate at a predetermined distance from the first plate. Is attached to the second plate, which is rotatably installed by being looped over, and the second belt is bridged between the relay pulley and the first roller, and the first roller is connected. A driving pulley that rotates the first roller by the torque of the motor transmitted via the belt, the relay pulley, and the second belt; and a motor gear attached to the first plate. A second roller coupled with mesh with, is obtained by a configuration having a roller driving gear for rotating the second roller in the rotational force of the motor is transmitted from the motor gear.

Thus, the developing roller and the photosensitive roller can be driven by a single motor. Further, it is possible to drive the developing roller and the photosensitive roller without using the intermediate gear.

Further, in the image forming apparatus of the present invention, in the above-described image forming apparatus, the second plate is made of aluminum die-cast.

As a result, it is possible to prevent the rotation of the rotating shaft of the drive system.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a motor which is mounted on a first plate to generate a rotational force, a motor pulley fixed to a rotating shaft of the motor, and a motor for rotating the motor. A motor gear fixed to the shaft,
A relay pulley that is attached to a second plate fixedly arranged in parallel with the first plate at a predetermined distance from the first plate and that is rotatably installed with a first belt stretched over a motor pulley; Attached to the second plate,
The second belt is stretched between the relay pulley and the first roller is connected, and the first belt is connected to the first pulley by the rotational force of the motor transmitted from the motor pulley via the first belt, the relay pulley, and the second belt. A drive pulley for rotating the first roller, a roller drive gear attached to the first plate, meshing with the motor gear and connected to the second roller, and rotating the second roller with the rotational force of the motor transmitted from the motor gear; , Which has an effect that two rollers can be driven by a single motor. Also, without using an intermediate gear,
This has the effect that it is possible to drive two rollers.

According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the second plate is made of aluminum die-casting, and the second plate prevents the rotation of the rotating shaft of the drive system. Has the effect that it becomes possible.

According to a third aspect of the present invention, in the first or second aspect, the first roller is a photosensitive roller serving as an image carrier, and the second roller is a photosensitive roller. An image forming apparatus that is a developing roller that develops a formed electrostatic latent image, and has an effect that a developing motor and a photosensitive roller can be driven by a single motor. Further, it has an effect that the developing roller and the photosensitive roller can be driven without using the intermediate gear.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is a schematic view showing the structure of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a drive transmission mechanism between a photosensitive roller and a developing roller in the image forming apparatus shown in FIG. FIG. 3 is a partially cutaway perspective view showing a drive transmission mechanism between a photosensitive roller and a developing roller in the image forming apparatus of FIG. 1, and FIG. 4 is a perspective view showing the photosensitive roller and the developing roller in the image forming apparatus of FIG. FIG. 5 is a bottom view showing the drive transmission mechanism of FIG.

As shown in FIG. 1, the main body 1 for forming an image is integrally housed in the apparatus main body 1 and is detachably mounted on the apparatus main body 1, thereby facilitating replacement of consumable parts. A unit 6 is provided. A fixed shaft 8 is attached to a side wall of the process unit 6.
A photoreceptor roller (first roller) 7 serving as an image carrier is rotatably supported on the fixed shaft 8. Photoconductor roller 7
Consists of an electrode thin film on the surface of a metal drum made of aluminum or the like and an organic photoconductive substance adhered to the electrode thin film.

A charger 9 is arranged near the photosensitive roller 7. When a high voltage is applied from a high-voltage power supply (not shown), the charger 9 moves along the rotation direction of the photoconductor roller 7 (in the illustrated case, the direction of the arrow A which is counterclockwise). The surface of the photosensitive roller 7 is uniformly charged.

A laser scanning unit (hereinafter, referred to as “LSU”) 10 is provided in the image forming apparatus. This L
The SU 10 includes a lens (not shown), a polygon mirror (not shown) for scanning a semiconductor laser beam, and the like. The SU 10 irradiates a laser beam to the photoconductor roller 7, which is light-modulated and uniformly charged with image data. To form an electrostatic latent image.

Further, in the vicinity of the photosensitive roller 7, a developing section for developing the electrostatic latent image formed on the photosensitive roller 7 is formed. The developing unit is rotatably supported on the side wall of the process unit 6 by the agitator 19 for stirring and transporting the toner 13 in the toner storage chamber 18 to the replenishing roller 12 while being rotated. A developing roller (second roller) 11 that supplies the toner 13 to the electrostatic latent image on the photoconductor roller 7 to perform development is provided. A negative potential is applied to the developing roller 11,
Thus, the supplied toner 13 is given a negative charge in advance. Further, a developing blade 15 that frictionally charges the toner 13 supplied to the developing roller 11 into a uniform thin layer state by pressing force is fixed to a blade mounting plate 14 bridged between side walls of the process unit 6. .

Then, the toner 13 is supplied to the photosensitive roller 7 by the developing roller 11, so that the toner 13 adheres to the electrostatic latent image whose charge has disappeared by the irradiation of the laser beam, so that a negative / positive image is formed. Process development is performed.

As shown, a paper cassette 2 is provided at the bottom of the image forming apparatus. Paper (recording medium) 3 is stored in a paper cassette 2, and the paper 3 is taken out one by one by a paper feed roller 4 and conveyed along a conveyance path. On the transport path, a plurality of transport rollers 5 for transporting the paper 3 taken out by the paper feed roller 4 to a printing unit on the downstream side in the transport direction, and a transfer roller 16 rotating in contact with the photosensitive roller 7 along the transport direction. It is provided. The transfer roller 16 is rotatably supported by the apparatus main body 1 and is pressed against the photosensitive roller 7. When a high voltage is applied, the toner image developed on the surface of the photosensitive roller 7 is transferred to the transfer roller 16. The image is transferred to the sheet 3 with a pressing force of 24.

A cleaning blade 17 is disposed to remove the toner 13 remaining on the surface of the photoreceptor roller 7 after the transfer roller 16 transfers the toner image to the paper 3.

A fixing device 20 is provided on the conveyance path behind the transfer roller 16. The fixing device 20 includes a heat roller 21 including a heat source such as a halogen lamp (not shown), and a pressure roller 22 that rotates in contact with the heat roller 21. Then, the transferred toner image is fixed to the sheet 3 by being fed between the rotating heat roller 21 and the pressing roller 22.

At the end of the transport path, a paper discharge roller 23 for discharging the paper 3 from the fixing device 20 to the outside of the apparatus and a paper discharge tray 2
5 are installed. Then, the sheet 3 on which the toner image has been transferred and fixed is sent to the sheet ejection roller 23 and is sent to the sheet ejection tray 25.
Is discharged.

A display unit 26 for transmitting device information to a user is provided on the front surface of the device main body 1.

Next, the printing operation of the image forming apparatus having such a configuration will be described.

In the image forming apparatus, the CPU rotates a motor (neither of which is shown) in response to a print request from a host computer (not shown), and performs a charging step, an exposing step,
Control of the developing step, the transferring step, the fixing step, etc. is performed.

First, in the charging step, a high voltage is applied to the wires in the charger 9 in a DC manner to cause corona discharge.
By generating a voltage of, for example, about -700 V on the grit plate, the surface of the photosensitive roller 7 rotating in the direction of arrow A is uniformly charged to about -700 V.

Next, in the exposure step, the laser light emitted from the LSU 10 is modulated in accordance with the character or image pattern data transmitted from the image processing section (not shown), and the laser light is applied to the surface of the photosensitive roller 7. Irradiate. Since the portion irradiated with the laser beam has an increased electric conductivity, the electric charge disappears only in that portion and an electrostatic latent image is formed.

In the developing step, the developing section charges the toner 13 to, for example, about -300V. As a result, the toner 13 is attracted to the surface portion of the photoreceptor roller 7 where the electrostatic latent image is formed, and development by the negative-positive process is performed.

In the transfer step, the paper 3 is fed to the paper feed roller 4
Is taken out of the paper cassette 2 and conveyed by the conveying roller 5 along the conveying path. Then, for example, +1 on the surface
Due to the electrostatic Coulomb force of the transfer roller 16 to which a voltage of about 000 V is applied, the toner 13 adsorbed on the surface of the photosensitive roller 7 is transferred to the paper 3.

In the last fixing step, the transferred toner image is fixed on the sheet 3 by the holding pressure of the pressure roller 22 in the fixing device 20 and the heat of the heat roller 21. Then, the paper 3 further passes through the transport path, and is
3, the paper is discharged to the paper discharge tray 25.

Here, a drive transmission mechanism between the photosensitive roller and the developing roller will be described with reference to FIGS. 2, 3, and 4. FIG.

As shown in the figure, these drive transmission mechanisms include a second plate 30A and a first plate 30B fixed to each other at predetermined intervals and arranged in parallel.
Is provided. A common motor (motor) 37 is attached to the first plate 30B. The second plate 30A is made of aluminum die-cast.

The rotating shaft of the common motor 37 passes through a hole formed in the first plate
A, a developing motor gear (motor gear) 32 and a photoreceptor motor pulley (motor pulley) 34B are fixed toward the front end.

A developing roller driving gear (roller driving gear) 33 meshing with the developing motor gear 32 is rotatably mounted on the first plate 30B.
The developing roller 11 is connected to the developing roller drive gear 33 via a developing roller transmission connection device 31.

Further, a deceleration pulley (relay pulley) 38B and a photosensitive roller driving pulley (drive pulley) 36B are rotatably mounted on the second plate 30A. The photosensitive roller 7 is connected to the photosensitive roller driving pulley 36B via a transmission connection device (not shown).

Here, as shown in the figure, a belt (for example, made of rubber or the like having flexibility) between the photosensitive member motor pulley 34B and the large-diameter pulley of the reduction pulley 38B and having teeth formed on the inner periphery thereof is provided. (First belt) 39A. Also, a belt (second belt) 39B made of, for example, flexible rubber or the like and having teeth formed on the inner periphery is applied between the small-diameter side pulley of the reduction pulley 38B and the photosensitive roller driving pulley 36B. Has been passed.

Thus, the rotational force of the common motor 37 is
The power is transmitted to a developing roller driving gear 33 that meshes with a developing motor gear 32 fixed to the rotation shaft of the common motor 37,
The developing roller 11 connected to the developing roller driving gear 33 is rotated. At the same time, the rotational force of the common motor 37 is transmitted from the photoreceptor motor pulley 34B, which is also fixed to the rotating shaft of the common motor 37, to the reduction pulley 38B via the belt 39A. The light is transmitted to the photoreceptor roller drive pulley 36B via the photoconductor roller drive pulley 36B. Thus, the photosensitive roller 7 connected to the photosensitive roller driving pulley 36B is rotated.

As described above, according to the present embodiment, the common motor 37 is provided, and the developing drive motor gear 3
2 and the photoreceptor motor pulley 34B are fixed, and the developing drive motor gear 32 and the photoreceptor motor pulley 34B transmit the rotational force of the shared motor 37 via the developing roller drive gear 33 attached to the first plate 30B. Developing roller 11 and second plate 30A
The developing roller 11 and the photosensitive roller 7 can be driven by a single motor because the light is transmitted to the photosensitive roller 7 through the photosensitive roller driving pulley 36B attached to the developing roller 11. Thus, cost reduction and space saving of the device can be achieved.

That is, the rotation speed of the photosensitive member 7 and the developing roller 11 is higher in the developing roller 11 than in the photosensitive member 7. If the reduction gear train is configured in view of this point, the developing roller driving gear 33 will be three-dimensionally overlapped with the photoconductor roller driving pulley 36B. In the present embodiment, the second
Since the drive system of the photosensitive roller 7 is arranged on the plate 30A and the drive system of the developing roller 11 is arranged on the first plate 30B, cost reduction and space saving of the drive transmission device can be achieved. You can do it.

Further, according to the present embodiment, the rotational force of the common motor 37 taken out from the photoconductor motor pulley 34B is transmitted to the reduction pulley 38B by the belt 39A, and further, the photoconductor roller drive pulley 36B is transmitted via the belt 39B. To rotate the photoconductor roller 7, the developing roller 11 and the photoconductor roller 7 can be driven without using an intermediate gear. Thereby, it becomes possible to suppress the occurrence of rotation unevenness, and the belt 39
By changing the lengths of A and 39B, the distance between the axes of the driving means can be arbitrarily changed, and space can be saved.

According to the present embodiment, since the second plate 30A is made of aluminum die-cast,
The post-processing of the hole position after the die-casting of aluminum improves the positional accuracy of the parts, and the rigidity of attachment of the reduction pulley gear shaft 42 and the photoconductor drive gear shaft 41 to the plate 30A is improved so that these gear shafts are rotating shafts. As a result, it is possible to reduce drive rotation unevenness.

Incidentally, the mounting position of the developing roller 11 and the photosensitive roller 7 may be reversed from that of the present embodiment. In this case, the developing roller 11 is connected to the belts 39A, 3A.
9B will be driven to rotate.

[0055]

As described above, according to the present invention, an effective effect that two rollers can be driven by a single motor can be obtained.

Further, according to the present invention, an effective effect is obtained that two rollers can be driven without using an intermediate gear.

If the second plate is made of aluminum die-cast, an effective effect that it is possible to prevent the rotation of the rotating shaft of the drive system can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a drive transmission mechanism between a photosensitive roller and a developing roller in the image forming apparatus of FIG. 1;

3 is a partially cutaway perspective view showing a drive transmission mechanism between a photosensitive roller and a developing roller in the image forming apparatus shown in FIG. 1;

FIG. 4 is a bottom view showing a drive transmission mechanism between a photosensitive roller and a developing roller in the image forming apparatus of FIG. 1;

FIG. 5 is a perspective view showing a main part of a power transmission mechanism in a conventional photosensitive roller and a developing roller.

FIG. 6 is a front view showing a main part of a power transmission mechanism in a conventional photoconductor roller and a developing roller.

[Explanation of symbols]

 7 Photoconductor Roller (First Roller) 11 Developing Roller (Second Roller) 30A Second Plate 30B First Plate 32 Developing Motor Gear (Motor Gear) 33 Developing Roller Drive Gear (Roller Drive Gear) 34B Photoconductor Motor Pulley ( Motor pulley) 36B Photoconductor roller drive pulley (drive pulley) 37 Shared motor (motor) 38B Reduction pulley (relay pulley) 39A Belt (first belt) 39B Belt (second belt)

Claims (3)

[Claims] A motor attached to a first plate to generate a rotational force; a motor pulley fixed to a rotating shaft of the motor; a motor gear also fixed to a rotating shaft of the motor; A relay pulley attached to a second plate fixedly arranged in parallel with the plate at a predetermined interval, a first belt being hung between the plate and the motor pulley, and rotatably installed; The first belt, the relay pulley, and the second belt are attached to a second plate, and a second belt is stretched between the relay pulley and the first roller. A drive pulley for rotating the first roller with the rotational force of the motor transmitted through the motor, and a drive pulley attached to the first plate and meshing with the motor gear Fit with the second roller is connected, an image forming apparatus characterized by having a roller drive gear for rotating the second roller in the rotational force of the motor that is transmitted from the motor gear. 2. An image forming apparatus according to claim 1, wherein said second plate is made of aluminum die cast. 3. The image forming apparatus according to claim 1, wherein the first roller is a photosensitive roller serving as an image carrier, and the second roller is a developing roller for developing an electrostatic latent image formed on the photosensitive roller. 3. The image forming apparatus according to claim 1, wherein: