JPH11119493A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of surely blocking, a followingly moving phase member being followingly moved by a drive transmission form the drive source, when it is separated from the drive transmission. SOLUTION: This image forming device is provided with a drive source M, a drive force transmitting means 23 transmitting the drive force by the drive source M, a followingly moving phase member 25 being followingly driven by the drive force transmitted by the transmitting means 23 and being controlled in phase, a transmission attach/detaching means 26 detaching or attaching the above transmitting system, at a specified position of the transmission system between the drive source M of the drive force transmitting means 23 and the followingly moving phase member 5, and a rotation blocking means 24 blocking the rotation of the followingly moving phase member 25, when the above transmitting system is detached by the transmission attach/detaching means 26.

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 a copying machine and a printer, and more particularly, to forming a toner image on an image carrier by an electrostatic recording method and transferring the toner image onto a transfer material. The present invention relates to an image forming apparatus of a type for performing recording.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus of a type in which a toner image is formed on an image carrier by an electrostatic recording method, and the toner image is transferred onto a transfer material and recorded, one common driving source is used. The transmission system for transmitting the driving force is divided into separate transmission systems by a planetary gear mechanism, and a part of the drive transmission system of the mechanism of the image forming apparatus is shared, thereby miniaturizing and simplifying the apparatus. Image forming apparatuses are known.

The above device transmits the driving force of a pulse motor as a driving source by a gear train having a planetary gear mechanism,
The following phase member whose phase is regulated by being driven by the gear train is rotated. A planetary gear of the planetary gear mechanism is revolved at a predetermined position of the gear train to separate the gear train and divide the gear train into separate transmission systems.

[0004]

However, when the gear train is cut off at a predetermined position, the follow-up phase member and the gear train interlocking with this member become rotatable and turn.
When the phase of the follower phase member is controlled by the number of pulses of the pulse motor, there is a problem in that the phase of the additional transmission member is shifted and control cannot be performed.

An object of the present invention has been made in view of the above-mentioned problems, and when a follow-up phase member which is driven and rotated by drive transmission from a drive source is disconnected from the drive transmission, the follow-up phase member is turned off. An object of the present invention is to provide an image forming apparatus that simply and reliably prevents rotation.

[0006]

The above object is achieved by the following means. That is, a driving source, a driving force transmitting means for transmitting the driving force by the driving source, a driving phase transmitted by the driving force transmitted by the driving force transmitting means, and a follower phase member whose phase is regulated, At a predetermined position of a transmission system between the drive source and the follower phase member of the driving force transmission unit, a transmission engagement / disconnection unit that disconnects or couples the transmission system, and the transmission system is disconnected by the transmission engagement / disengagement unit. And a rotation preventing means for preventing rotation of the follow-up phase member when the image forming apparatus is in an inoperative state.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the configuration of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of the image forming apparatus, and FIG. FIG. 4 is a sectional view of another configuration of the follower phase member and the rotation preventing member.

Prior to a detailed description of an embodiment of the present invention, the structure and operation of the color image forming apparatus of the present invention will be described with reference to FIG. After each color toner image sequentially formed on the image carrier is superimposed, the color image is formed by transferring the toner image onto a transfer material once by a transfer unit, and then separated from the surface of the image carrier by a separation unit. This is a color image forming apparatus.

In FIG. 1, reference numeral 10 denotes a photosensitive drum serving as an image carrier, which is formed by applying an OPC photosensitive member on a drum base, and is grounded and driven to rotate clockwise in the drawing. Reference numeral 12 denotes a scorotron charger, which is provided with a uniform charge on the peripheral surface of the photosensitive drum 10 by a grid and a corona discharge wire by a corona discharge wire. Prior to the charging by the scorotron charger 12, in order to eliminate the history of the photoconductor up to printing, exposure is performed by a PCL (pre-charging static eliminator) 11 using a light emitting diode or the like, and the peripheral surface of the photoconductor is neutralized. deep.

After the photosensitive drum 10 is uniformly charged, the image exposure means 13 performs image exposure based on the image signal. The image exposing means 13 is a main scanning performed by bending a light path by a reflection mirror 134 through a polygon mirror 131, an fθ lens 132, and a cylindrical lens 133 which rotate by using a laser diode (not shown) as a light emitting light source.
A latent image is formed by rotation (sub-scan) of the photosensitive drum 10.

Around the periphery of the photoreceptor drum 10, developing devices 14 (14Y) each containing a developer containing a toner such as yellow (Y), magenta (M), cyan (C), and black (K) and a carrier are provided. , 14M, 14C, 14K), and a developing sleeve 14 for developing the first color of yellow, which includes a magnet and rotates while holding a developer.
1 is performed.

The gap between the developing sleeve 141 and the photosensitive drum 10 in the developing area is larger than the layer thickness. During this time A
The C bias and the DC bias are superimposed and applied.

After the visualization of the first color has been completed, the magenta image forming process for the second color is started, and the scorotron charger 1
2, and a latent image based on the image data of the second color is formed by the image exposure unit 13. At this time 1
The static elimination by the PCL 11 performed in the color image forming process is not performed because the toner attached to the image portion of the first color scatters due to a sharp drop in the surrounding potential.

An image forming process similar to that for the second color magenta is performed for the third color cyan and the fourth color black, so that a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

On the other hand, the half-moon roller 1
The one transfer material P carried out via 6 is temporarily stopped, and is fed to the transfer area by the rotation of the registration roller 17 when the transfer timing is adjusted.

In the transfer area, a transfer roller serving as transfer means 18 is pressed against the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing, and the fed transfer material P is sandwiched to collectively form a multicolor image. Is transcribed. The transfer roller is pressed against or separated from the image carrier 10 by a cam member provided on the follower phase member 25 to which the driving force of the pulse motor M is transmitted.

Next, the transfer material P is separated from the peripheral surface of the photoreceptor drum 10 through the exposure means 30 and the separation pole 19 and is conveyed to the fixing device 20, where the heat roller 201 and the pressure roller 202
After the toner is welded by heating and pressurizing, the toner is discharged to the outside of the apparatus via the discharge roller 21.

The transfer roller of the transfer means 18 is separated from the peripheral surface of the photosensitive drum 10 by the follow-up phase member 25 after passing through the transfer material P to prepare for the formation of the next toner image.

On the other hand, the photosensitive drum 1 from which the transfer material P is separated
No. 0 removes and cleans the residual toner by pressing the blade 221 of the cleaning device 22. The blade 221 is driven by a cam member provided on the follow-up phase member 25 and presses against the photosensitive drum 10. Again, after receiving the charge elimination by the PCL 11 and the charge by the scorotron charger 12, the process enters the next image forming process. After cleaning the surface of the photosensitive drum 10, the blade 221 is driven by a cam member provided on the follow-up phase member 25 and is separated from the peripheral surface of the photosensitive drum 10.

Next, each component of the image forming apparatus and its operation will be described in detail with reference to FIGS.

A photosensitive drum 10 as an image carrier is shown in FIG.
As shown in (1), a uniform charging action by the scorotron charger 12 is performed on the peripheral OPC photosensitive member by the stable rotation operation.

The image exposure means 13 forms an electrostatic latent image by receiving light exposure of the semiconductor laser unit 135 in FIG. The image data is sent to a laser diode (LD) modulation circuit, and the LD of the semiconductor laser unit emits light according to the modulated image signal, and is projected on the polygon mirror 131.

In the developing means 14, the toner supplied from the toner replenishing box shown in FIG. 1 is dropped to the right end of the developing device, is agitated and mixed with the carrier by a pair of agitating screws 142, and is set to a predetermined charge amount. .

The paper feeding unit is configured to transfer the transfer paper P stacked on the push-up plate 152 by rotating the half-moon roller 16 shown in FIG.
By the action of the claw 151, only one of the uppermost layers is carried out. The transfer paper P carried out from the paper supply cassette 15 enters the conveyance path, and immediately after the leading end passes through the registration roller 17, a motor (not shown) is temporarily stopped by detection of a paper supply sensor (not shown). When the motor is ready, the motor starts rotating again, and the paper is fed to the transfer area while maintaining a predetermined angle with respect to the surface of the photoconductor.

The transfer means 18 includes a follower phase member 25 shown in FIG.
The lever 182 by the cam member 251 provided on the shaft 1
The transfer roller is rotatably provided on the lever 184 by rotating about the shaft 183a by the action of a spring 185, following the pin 183 provided on the lever 182. 181 presses against the image carrier 10. Then, the toner image is transferred to the transfer material by the transfer roller 181. The transfer roller 181 is kept at a position away from the image carrier 10 during the formation of a color image, and is pressed against only at the time of transfer.

The fixing means 20 has a nip portion formed between an upper roller 201 which incorporates a fixing heater in FIG. 1 and is driven and rotated clockwise, and a lower roller 202 which is pressed against the upper roller 201 and driven to rotate. To heat and transfer the transfer material P to fuse the toner image.

The separating means 19 separates the toner image from the photosensitive drum 10 after transferring the toner image to the transfer material P in FIG.

The cleaning device 22 includes a cam member 252 provided on the follower phase member 25 in FIG.
As a result, the lever 222 pivots around the shaft 222a, and the blade 221 linked to the lever 222 pivots around the shaft 221a by the action of the spring 223, so that the blade 221 presses against the image carrier 10 and removes residual toner. Remove and clean.
The blade 221 is used to hold the image carrier 10 during color image formation.
More distant.

The driving source is a pulse motor M which rotates forward or backward by a pulse signal in FIG. The pulse motor M rotates the follow-up phase member 25 via a gear train, which is a driving force transmission unit 23 described later, and controls the phase to a predetermined phase.

In FIG. 2, the driving force transmitting means 23 includes a gear G1, a gear G2, and a sun gear G driven by a pulse motor M.
3, transmitted to the planetary gears G4, G5, and G6 to rotate the follower phase member 25. The rotation axes of the gears are G1a, G2a, G3a, G4a, G5a, G
6a.

The follower phase member 25 is rotated by the gear 6 of the driving force transmitting means 23 in FIGS. 2 and 3, and the phase in the rotational direction is regulated by the pulse motor M. Further, the follower phase member makes one rotation in one cycle of the apparatus. Follow-up phase member 2
5 includes a gear G7, a cam member 251, and a cam member 252. The gear G7 meshes with the gear G6,
Is transferred to the transfer roller 18 via the levers 182 and 184 described above.
1 is pressed against or separated from the image carrier 10. The cam member 252 presses or separates the blade 221 from the image carrier 10 via the lever 22.

The transmission engagement / disengagement means 26 is connected to the sun gear G3 in FIG.
The support plate 261 is provided coaxially with the rotation axis G3a of the
A planetary gear G4 revolving around the sun gear G3 on 61
To separate or connect the planetary gear G4 and the gear G5.

As shown in FIGS. 2 and 3, the rotation preventing means 24 is means for preventing the follow-up phase member 25 from rotating.
A malt plane (trade name) 241, a follow-up phase member 25, and a washer 244, which are a part of the rotation preventing means, are incorporated in a shaft 25 a provided on the substrate 231, and are fixed by E washers. Then, the follower phase member 25 is
1 has been pressed. When the planetary gear G4 and the gear G5 are separated, the follower phase member 25 is
Rotation is prevented by the frictional force of 41.

As another example of the follow-up phase member and the rotation preventing means, as shown in FIG. 4, a plate spring 242, a follow-up phase member 25, and a washer 244 are mounted on a substrate 231 and a shaft 25a planted on the substrate. Are fixed with E washers. The follower phase member 25 is directly pressed by the leaf spring 242 which is a part of the rotation preventing member, and when the transmission system is disconnected, the follower phase member 25 is prevented from rotating.

Here, the operation of the main part of the image forming apparatus will be described in more detail with reference to FIGS.

First, as shown in FIG.
Is rotated by the pulse signal, the gear G1 is rotated. Then, the gear G2 meshing with the gear G1 rotates. Further, the sun gear G3 meshing with the gear G2 rotates, and the planetary gear G4
Revolves counterclockwise in FIG. 2, and the planetary gear G4 becomes the gear G5.
And become engaged. When the gear G5 rotates, the gear G6
The follower phase member 25 having the gear G7 is rotated via. Then, the cam member 2 provided on the follower phase member 25
The lever 182 is operated by the rotation of the lever 51, and the lever 184 is operated by the spring 185 following the pin 183 planted on the lever 182. Then, the transfer roller 181 comes into pressure contact with the surface of the image carrier 10. At this time, no force acts on the cam member 251 and the lever 182. On the other hand, by the rotation of the cam member 252 provided on the follow-up phase member 25, the lever 222 operates to operate the blade 221 as a cleaning member, and the plate 2
The spring 21 is pressed against the surface of the photosensitive drum 10 by a spring 223. At this time, the cam member 251 and the lever 22
No. 2 is in a state where no force acts.

Next, when the pulse motor M rotates in the reverse direction, the gear 1 and the gear 2 rotate, the sun gear G3 rotates in the direction opposite to the above-mentioned rotation direction, and the planetary gear G4 revolves clockwise in the figure to rotate the planetary gear. The gear G4 and the gear G5 mesh with each other. Then, the follow-up phase member 25 is prevented from rotating by the malt plane (trade name) 241 as the rotation preventing member 24, and the phase with the pulse motor M is not shifted. The pulse motor M
The reverse rotation causes the gear G8 of the toner replenishing device to engage with the gear G8, and the phase of the toner replenishing device can be controlled.

In the embodiment, the malt plane 241 and the leaf spring 242 are used as the pressing method of the rotation preventing means 24. However, the pressing method is not limited thereto. For example, a compression spring, synthetic rubber, or the like may be used.

Further, in the embodiment, the rotation of the follower phase member 25 is prevented by the rotation preventing means 24, but the invention is not limited to this. For example, the gear G6, the gear G
The rotation of the follower phase member 25 may be prevented by preventing the rotation of the follower 5.

Further, in the embodiment, the cam member whose phase is regulated is provided in the follower phase member 25. However, the present invention is not limited to the cam member. , The transfer roller 181 and the plate 221 of the cleaning member may be pressed against or separated from the image carrier 10.

[0041]

According to the structure described above, the following effects can be obtained. According to the first aspect of the present invention, a driving force transmitting means for transmitting the driving force from the driving source is provided, and a follow-up phase member which is driven by the driving force transmitting means and whose phase in the rotational direction is regulated is provided. A transmission / disengagement means for disconnecting or connecting the drive train at a predetermined position of the drive train of the drive force transmission means, and preventing the rotation of the follow-up phase member when the transmission system is disconnected by the transmission / disengagement means Since the rotation preventing member is provided, the rotation of the follower phase member can be easily and reliably prevented when the drive transmission system is disconnected. When the phase of the follower phase member is regulated by the amount of rotation of the drive source, the phase does not shift even if the transmission system is disconnected.

According to the second aspect of the present invention, the transmission and disengagement means includes a planetary gear mechanism constituted by at least a sun gear and a planetary gear revolving around the sun gear, thereby transmitting the transmission system of the driving force transmission means. Since the transmission system is separated or connected, the transmission system can be easily separated and connected reliably.

According to the third aspect of the present invention, the transfer member for transferring the image visualized by the developer on the image carrier to the transfer material based on the rotation of the follow-up phase member is provided. The cleaning member, which removes the developer remaining on the image carrier after being transferred to or transferred from the transfer material, is pressed against or separated from the image carrier, so that the transfer member and the cleaning member can be easily and reliably mounted on the image carrier. Can be pressed against or separated from the body.

According to the fourth aspect of the present invention, the follower phase member includes a cam member for pressing or separating the transfer member on the image carrier or a cam member for pressing or separating the cleaning member on the image carrier. Since the transfer member and the cleaning member are provided, the transfer member and the cleaning member can be easily pressed and separated from the image carrier.

According to the fifth aspect of the present invention, the rotation preventing means applies a brake to the transmission system between the follower phase members or the follower phase member from a predetermined position of the transmission system to apply the brake to the follower phase member. Since the rotation is prevented, the rotation of the follower phase member can be easily and reliably prevented.

[Brief description of the drawings]

FIG. 1 is an overall configuration cross-sectional view of an image forming apparatus according to an embodiment.

FIG. 2 is a configuration diagram of a main part of the image forming apparatus according to the embodiment.

FIG. 3 is a sectional view of the configuration of a follow-up phase member and a rotation preventing unit of FIG. 2;

FIG. 4 is a sectional view of another configuration of the follower phase member and the rotation preventing means.

[Explanation of symbols]

 Reference Signs List 10 image carrier (photosensitive drum) 18 transfer means 181 transfer roller 19 separation means (separation pole) 22 cleaning device 221 blade 23 driving force transmission means 24 rotation prevention means 25 follow-up phase member 251, 252 cam member 26 transmission Removal means P Transfer material G1, G2, G5, G6, G7, G8 Gear G3 Sun gear G4 Planetary gear M Pulse motor (drive source)

Claims (5)

[Claims] 1. A driving source, a driving force transmitting means for transmitting a driving force from the driving source, and a follow-up phase in which a driving force is transmitted by the driving force transmitting means to rotate and rotate, and a phase is regulated. A member, transmission engaging / disengaging means for separating or connecting the transmission system at a predetermined position of the transmission system between the drive source of the driving force transmitting means and the follow-up phase member, and the transmission system by the transmission engaging / disengaging means. An image forming apparatus, comprising: a rotation preventing unit configured to prevent rotation of the follow-up phase member when is separated. 2. The transmission and disengagement means includes a planetary gear mechanism including at least a sun gear and a planetary gear revolving around the sun gear, and the transmission system is moved at the predetermined position by the revolution of the planetary gear. The image forming apparatus according to claim 1, wherein the image forming apparatus is separated or coupled. 3. A transfer member for transferring an image visualized by a developer on an image carrier to a transfer material on the basis of the rotation of the follow-up phase member is pressed against or separated from the image carrier, 3. The image forming apparatus according to claim 1, wherein a cleaning member that removes a developer remaining on the image carrier after being transferred to the transfer material is pressed against or separated from the image carrier. 4. 4. The image forming apparatus according to claim 1, wherein the follow-up phase member has a cam member that presses or separates the transfer member onto or from the image carrier, or a cam member that presses or separates the cleaning member onto or from the image carrier. Claim 1
The image forming apparatus according to any one of claims 1 to 3, wherein 5. The rotation preventing means applies a brake to the transmission system or the follower phase member between the follower phase members from a predetermined position of the transmission system to prevent the follower phase member from rotating. The image forming apparatus according to claim 1, wherein: