JPH10142876A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing the situation where an electrostatic latent image carrier is worn more than required by a member coming into contact therewith, because the electrostatic latent image carrier is driven more than required for forming an image, in an image forming device which is of an electrophotographic system image forming device and constituted so that the electrostatic latent image carrier such as a photoreceptor driven to move its surface and a recording material carrying device for carrying a recording material to which a toner image is transferred from a position for housing the recording material to an ejecting position through a transferring position are driven by the same drive source. SOLUTION: The rotary drive of a photoreceptor drum and the conveyance of the recording material are attained by the same motor M1 and a gear g108 coaxial with respect to the photoreceptor drum is rotationally driven by the motor M1 with a gear train g101-g107. But, a clutch CL1 is provided in a transmission path for the driving force of the motor M1, to permit or release the transmission of power. Before the recording material is ejected outside a device and the motor M1 is stopped, the clutch CL1 is let out to stop the rotary drive of the drum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, and more particularly, to driving of an electrostatic latent image carrier such as a photosensitive member.
The present invention relates to an image forming apparatus in which conveyance from a storage position of a recording material onto which a toner image formed on an electrostatic latent image carrier is transferred to a discharge position via a transfer position is performed by the same drive source.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an image corresponding to a document image is generally formed on a recording material as follows. That is, in a monochrome image forming apparatus, an electrostatic latent image carrier such as a photoconductor is charged by a charging device, and an image is exposed to the charged area to form an electrostatic latent image corresponding to a document image. The latent image is developed by a developing device to form a visible toner image, the toner image is transferred onto a recording material by a transfer device, and the toner image on the recording material is fixed by a fixing device to obtain a desired image.

In a color image forming apparatus,
For example, toner images of each color such as cyan, yellow, magenta, and black are sequentially formed on the electrostatic latent image carrier as described above, and each time a toner image of one color is formed, an intermediate image of a transfer belt or the like is formed. After the toner images of all colors are transferred to the intermediate transfer member to form a multiple toner image on the intermediate transfer member, the multiple toner images are transferred to the recording material by the transfer device. You. Subsequent processing is the same as in the case of monochrome.

[0004] Such an electrophotographic image forming apparatus usually has a driven body which is driven to rotate for image formation. Examples of the driven member include an electrostatic latent image carrier such as a photoconductor on which an electrostatic latent image is formed, a charging roller for charging the electrostatic latent image carrier, and the like. Rotating brush for charging, developing roller and developing sleeve for development, intermediate transfer member on which multiple toner images are formed, and intermediate transfer of toner image from electrostatic latent image carrier to recording material and from electrostatic latent image carrier A transfer roller or a transfer rotating brush for transferring the recording material from the intermediate transfer member to the recording material, or transporting the recording material from the storage position to the transfer position,
A recording material transport mechanism including a roller, a belt, and the like for transporting the toner from the transfer position to the fixing device or discharging the toner from the fixing device to the outside of the image forming device can be used.

[0005] These driven members are driven by a driving source (generally,
), Or driven by a driving force transmission mechanism such as a gear transmission mechanism or a belt transmission mechanism that transmits a driving source and its driving force to a driven body. At this time, it is conceivable to provide a drive source for each of the driven members and drive them. However, in this case, a large number of drive sources must be provided, and the entire image forming apparatus is reduced in size and cost In consideration of the easiness of drive control of the drive source, it is general that a plurality of driven bodies are driven by a single drive source. In the case where a plurality of driven members are driven by a single driving source, driving of a gear transmission mechanism or the like for driving one driven member in order to reduce the size and cost of the entire image forming apparatus. A part of the power transmission mechanism may be used as a driving force transmission mechanism for driving another driven body.

[0006]

However, when the electrostatic latent image carrier such as a photosensitive member and the recording material transport mechanism are driven by the same drive source, the recording material is transported outside the apparatus. Must be driven until it is discharged to
As a result, before the recording material is discharged out of the apparatus, for example, after the transfer of the toner image to the recording material is completed, the driving of the electrostatic latent image carrier for image formation may be stopped. Nevertheless, the electrostatic latent image carrier continues to be driven more than necessary until the recording material transport mechanism is stopped.

For this reason, the electrostatic latent image carrier is made of a member abutting on the member, for example, a charging roller or a rotating brush for charging, a developing roller or a developing sleeve for development, a transfer roller or a transfer for transfer. The rotating brush for cleaning, the cleaning blade and the cleaning roller for removing the residual toner, are unavoidably worn due to the rotation required for image formation, and the life of the electrostatic latent image carrier is shortened. .

Accordingly, the present invention is an electrophotographic image forming apparatus, in which an electrostatic latent image carrier such as a photosensitive member driven so as to move its surface and a recording material on which a toner image is transferred are accommodated. A recording material transport mechanism that transports from a position to a discharge position through a transfer position is an image forming apparatus driven by the same drive source, and the electrostatic latent image carrier is driven for image forming needs It is an object of the present invention to provide an image forming apparatus that can be driven as described above and can avoid a situation in which a member abutting on an electrostatic latent image carrier wears more than necessary.

[0009]

According to the present invention, there is provided an electrostatic latent image carrier driven so that its surface is moved, the surface of which is charged by a charging device. An electrostatic latent image is formed by exposing the electrostatic latent image carrier surface to an image corresponding to a document image, and the electrostatic latent image is developed into a toner image by a developing device, and the toner image is transferred to a recording material. An image forming apparatus having a recording material transport mechanism configured to transport the recording material from a storage position thereof to a discharge position via a position where the toner image is transferred, and the electrostatic latent image carrier is driven The recording material transport mechanism is driven by the same driving source as the driving source for driving the electrostatic latent image carrier and the driving of the driving source. Driven by a second transmission mechanism for transmitting force, It said first transmission mechanism is to provide an image forming apparatus characterized by having a middle from it so as not to transmit the previously drive transmission releasing mechanism of the transmission path of the driving force transmitted from the driving source.

The image forming apparatus of the present invention may be an image forming apparatus for transferring a toner image formed on an electrostatic latent image carrier directly onto a recording material, such as a monochrome image forming apparatus. For example, like a color (multicolor) image forming apparatus, a toner image formed on an electrostatic latent image carrier is temporarily transferred to an intermediate transfer member such as an intermediate transfer belt, and then the toner image on the intermediate transfer member is transferred. May be an image forming apparatus for transferring the image on a recording material. In any case, examples of the image forming apparatus include a printer and a copying machine.

As the electrostatic latent image carrier, a photoconductor can be exemplified. The electrostatic latent image carrier can be formed, for example, in a drum shape or a belt shape, and in these cases, the surface is rotationally driven so as to move. The recording material transport mechanism,
For example, one that conveys a recording material by passing the recording material between a pair of rollers that are rotationally driven, one that conveys the recording material on a belt that is wound around two or more rollers and that is rotationally driven, and the like Can be mentioned. The recording material transport mechanism may use these roller pairs or belts for one or two
It has the above.

The first and second transmission mechanisms may be, for example, a gear transmission mechanism connected to a drive source such as a motor, a belt transmission mechanism, or a combination thereof. In any case, a part of the transmission mechanism may be common to the first and second transmission mechanisms. Note that the third, fourth, fifth, and sixth transmission mechanisms described below can also be gear transmission mechanisms, belt transmission mechanisms, and the like, and two or more transmission mechanisms that transmit the driving force of the same driving source. May be common to other transmission mechanisms.

[0013] The drive transmission canceling mechanism of the first transmission mechanism includes:
For example, it may be a clutch provided in the middle of the driving force transmission path. The same applies to the drive transmission release mechanism of the third transmission mechanism and the drive transmission release mechanism of the fifth transmission mechanism described below. In the image forming apparatus of the present invention, the electrostatic latent image carrier is driven by the drive source via the first transmission mechanism so that the surface moves, the surface is charged, the image is exposed, and the electrostatic latent image is exposed. An image is formed, and the electrostatic latent image is developed into a toner image. In a monochrome image forming apparatus, the toner image is directly transferred to a recording material. In a color image forming apparatus, the toner image is temporarily transferred to an intermediate transfer member, and is similarly transferred to the intermediate transfer member every time a toner image of another color is similarly formed. After being formed on a transfer body, it is transferred to a recording material.
In any case, the recording material to which the toner image is transferred is conveyed from its storage position (for example, a recording material storage cassette) to the transfer position by a recording material conveyance mechanism driven via a second transmission mechanism by a driving source. After the toner image is transferred, the toner image is conveyed to a discharge position (for example, on a discharge tray outside the image forming apparatus).

In the conventional image forming apparatus, the electrostatic latent image carrier driven by the same driving source as the recording material conveying mechanism is continuously driven until the conveyance of the recording material to the discharge position is completed. In the image forming apparatus of the present invention, for example, control means for performing operation control of the drive source and drive force transmission release control of the drive transmission release mechanism of the first transmission mechanism is provided, and before stopping the drive source, The drive transmission release mechanism can release the transmission of the driving force to the electrostatic latent image carrier, whereby the electrostatic latent image carrier can be stopped before the conveyance of the recording material is completed.

The timing for releasing the transmission of the driving force to the electrostatic latent image carrier by the drive transmission release mechanism of the first transmission mechanism is before the drive source is stopped as described above, and the monochrome image formation is stopped. In the case of the apparatus, for example, after the transfer of the toner image to the recording material is completed, or when the toner remaining on the surface of the electrostatic latent image carrier is removed, the removal may be completed. In the case of a color image forming apparatus, for example, toner images of all colors
After the next transfer, or further, after the primary transfer toner image is secondarily transferred to the recording material, or after the removal of the residual toner is completed, it is conceivable.

In any case, the driving of the electrostatic latent image carrier can be stopped before the conveyance of the recording material is completed. A charging roller, a charging fixed brush, a charging rotating brush, a developing roller and a developing sleeve for developing, a transfer roller for transferring, a transferring fixed brush, a transferring rotating brush, a cleaning blade for removing residual toner, The amount of wear caused by the cleaning roller and the like is suppressed as compared with the conventional case where the recording material is rotated and driven until the conveyance of the recording material is completed.

Here, in the case where the charging device in the image forming apparatus of the present invention includes a charging rotary brush which is driven to rotate in contact with the electrostatic latent image carrier, In this manner, the charging rotary brush may be driven to rotate and stopped. This way,
The contact state of the brush bristles of the charging rotary brush with the electrostatic latent image carrier can be maintained normally, and the brush bristles are rotated in a normal rotation direction (a rotation direction when the brush bristles are rotated for charging).
A rotational force in a direction opposite to the above is applied, thereby causing the brush hairs to be disturbed, thereby preventing the electrostatic latent image carrier from being charged poorly. A third driving mechanism for transmitting the driving force of the driving source, the driving mechanism being the same as the driving source for driving the electrostatic latent image carrier, and a transmission mechanism including a driving transmission canceling mechanism; In the case of being driven, the control means also performs the drive force release control of the drive transmission release mechanism of the third power transmission mechanism, and causes the drive transmission release mechanism of the first power transmission mechanism to carry out the electrostatic latent operation. Simultaneously with or immediately after canceling the transmission of the driving force to the image carrier, the drive transmission canceling mechanism of the third transmission mechanism cancels the transmission of the driving force to the rotating brush for charging. When the charging rotary brush is driven by a charging rotary brush driving source and a fourth transmission mechanism that transmits a driving force of the driving source, the control means controls the charging rotary brush driving source by At the same time or immediately after causing the drive transmission release mechanism of the first power transmission mechanism to release the transmission of the driving force to the electrostatic latent image carrier, the operation of the charging rotary brush drive source is stopped. Let it.

When the developing device in the image forming apparatus of the present invention includes a developing sleeve which is brought into contact with the electrostatic latent image carrier and is driven to rotate, the developing device is configured as follows. The developing sleeve may be driven to rotate. By doing so, the contact state between the developing sleeve and the electrostatic latent image carrier is normally maintained, and the occurrence of defective development is prevented. The developing sleeve is driven by the same driving source as the driving source for driving the electrostatic latent image carrier and a fifth transmission mechanism for transmitting the driving force of the driving source, the transmission sleeve including a driving transmission canceling mechanism. In this case, the control means also causes the drive transmission release mechanism of the fifth transmission mechanism to perform drive force transmission release control, and causes the drive transmission release mechanism of the first transmission mechanism to carry out the transfer of the electrostatic latent image. Simultaneously with or immediately after releasing the transmission of the driving force to the body, the driving transmission releasing mechanism of the fifth transmission mechanism releases the transmission of the driving force to the developing sleeve. When the developing sleeve is driven by a developing sleeve driving source and a sixth transmission mechanism for transmitting the driving force of the driving source, the control means also controls the operation of the developing sleeve driving source. The developing sleeve drive source is stopped simultaneously with or immediately after the drive transmission release mechanism of the first transmission mechanism releases the transmission of the driving force to the electrostatic latent image carrier.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a full-color laser printer according to the present invention. This printer includes a photosensitive drum 2, a laser scanning optical system 4, a full-color developing device 5, an intermediate transfer unit 1, a separating device 8, a feeding device 8 that is driven to rotate clockwise in the figure by a motor M1 described below via a gear transmission mechanism. A paper cassette CS and the like are provided.

Around the photosensitive drum 2, a charging rotary brush 3 disposed in contact with the photosensitive drum 2, the developing device 5, the transfer unit 1, and a cleaning blade in contact with the photosensitive drum 2 A cleaning device 62 having a 621 is disposed. The charging brush 3 can be charged on the surface of the photosensitive drum 2 by being rotationally driven counterclockwise in the figure by a motor M2 described later via a gear transmission mechanism. The charging brush 3 is driven to rotate at a peripheral speed higher than the peripheral speed of the photosensitive drum 2.

The laser scanning optical system 4 includes well-known components such as a laser diode, a polygon mirror, and an fθ optical element, and its control unit (not shown) includes cyan (C),
Image data for each color of magenta (M), yellow (Y), and black (Bk) is input from a host device such as a computer to which the printer is connected, and a laser beam corresponding to the image data for each color is charged by a charging brush. By irradiating the photosensitive drum 2 from between the developing device 3 and the developing device 5, an electrostatic latent image corresponding to each color can be formed on the surface of the photosensitive drum 2.

The full-color developing device 5 has four color developing devices 5C, 5C containing developers containing cyan (C), magenta (M), yellow (Y), and black (Bk) toners.
M, 5Y, and 5Bk are attached to the developing rack 500. The developing rack 500 can be driven to rotate clockwise in the figure by a developing rack motor (not shown) with the support shaft 5a as a fulcrum.

Each of the color developing units 5C, 5M, 5Y and 5Bk is
Developing sleeves 50C, 50M, 50Y, 50B respectively
k. Each developing sleeve is flexible, and a driving roller (not shown) having an outer diameter slightly smaller than the inner diameter of the sleeve is inserted therein. Both ends of the sleeve are pressed by pressing guides (not shown) from behind. ) Is pressed against the drive roller. The slack portion of the developing sleeve formed on the opposite side by the pressure contact flexibly contacts the photosensitive drum 2. When each developing sleeve is located at the developing position,
The rotation is driven by a sleeve drive roller that is rotationally driven by a motor M2 described later via a gear transmission mechanism. Each time an electrostatic latent image corresponding to each color is formed on the photosensitive drum 2, the developing device 5 moves the corresponding color developing device to the developing position D.
The electrostatic latent image of each color formed on the photosensitive drum 2 is rotated by driving to the position, and can be developed by the developing device corresponding to the color.

The intermediate transfer unit 1 has an endless intermediate transfer belt 10. The intermediate transfer belt 10 includes a belt drive roller 11, a support roller 12, a tension roller 1
4 and a roller group consisting of a rotatable primary transfer roller 13. The drive roller 11 is driven to rotate counterclockwise in the figure by a motor M1 which is the same as the motor for driving the photosensitive drum 2 via a gear transmission mechanism described later, whereby the intermediate transfer belt 10 is also driven to rotate counterclockwise in the figure. Is done.

Further, the belt 10 is pressed by the primary transfer roller 13 and comes into contact with the photosensitive drum 2, and this contact portion becomes a primary transfer portion T1. A primary transfer power supply (not shown) is connected to the primary transfer roller 13, and a primary transfer voltage can be applied for primary transfer of the toner image on the photosensitive drum to the intermediate transfer belt 10. Further, the secondary transfer roller 7 can be pressed against the intermediate transfer belt 10 at a portion supported by the support roller 12. This contact portion becomes the secondary transfer portion T2. A secondary transfer power supply (not shown) is connected to the secondary transfer roller 7, and a secondary transfer voltage can be applied to the transfer roller 7 from the secondary transfer roller 7. The secondary transfer roller 7 is pressed against the intermediate transfer belt 10 by the transfer voltage. When a recording material passes between the transfer roller 7 and the recording material, the toner image on the intermediate transfer belt 10 can be transferred to the recording material.

A cleaning device 61 is disposed between the secondary transfer portion T2 and the primary transfer portion T1 (more precisely, up to the tension roller 14) in the surface moving direction of the intermediate transfer belt 10. The cleaning device 61
By having the cleaning blade 611 and bringing the blade 611 into contact with the portion of the intermediate transfer belt 10 supported by the support roller 12, the toner remaining on the intermediate transfer belt 10 can be scraped off.

The cleaning blade 611 and the secondary transfer roller 7 can be brought into contact with and separated from the intermediate transfer belt 10 as necessary by a cam device (not shown). In the paper feed cassette CS,
A sheet-like recording material (transfer sheet here) to which the toner image is transferred is stored, and the recording material stored by the paper feed roller 91 can be sent out one by one. In the recording material conveyance path indicated by a dotted line in the figure, a conveyance roller pair 92 for conveying the recording material sent from the cassette CS to the timing roller pair 93 and a toner image on the intermediate transfer belt 10 are synchronized. A timing roller pair 93 for supplying the recording material to the secondary transfer portion T2 is disposed.

A separating device 8 for separating the recording material from the intermediate transfer belt 10 is disposed downstream of the secondary transfer portion T2 in the recording material transport path. The separating device 8 is composed of a static elimination needle. Further downstream of the separation device 8,
A transport belt 941 for transporting the separated recording material to the belt fixing device 95 is provided. Conveyor belt 94
1 is wound around a driving roller 942 and a driven roller 943, and is rotated clockwise in the drawing.

A belt fixing device 95 for heating and fixing the toner image on the recording material, a pair of conveying rollers 96, 97, 98, and a pair of discharge rollers 99 are disposed further downstream of the conveyor belt 941. The recording material discharged by 99 is stored on a discharge tray TR. The belt fixing device 95 includes a fixing roller / drive roller 951, a heating roller / driven roller 952 distant from the fixing roller / drive roller 951, an endless heating belt 953 wrapped around these, and a belt 9.
And a backup roller 955 opposed to the drive roller 951 with the intervening 53. The nip portion between the backup roller 955 and the belt 953 becomes the fixing portion F.
The belt 953 is in contact with a release agent application roller 954 that applies silicone oil as a release agent for preventing adhesion of the molten toner.

In the vicinity of the discharge roller pair 99, a sensor SE1 for detecting the discharged recording material is disposed. The detection signal of the sensor SE1 is input to a control unit CONT that controls the operation of the entire printer (see FIG. 4). The above-described paper feed roller 91, transport roller pair 92, timing roller pair 93, transport belt 941, belt fixing device 95,
Conveyance roller pair 96, 97, 98 and discharge roller pair 99
(Hereinafter referred to as a recording material transport system.)
Is driven via a gear transmission mechanism. However, the paper feed roller 91, the transport roller pair 92, and the timing roller pair 93 are controlled to a paper feed position or a paper non-feed position at a predetermined timing by a paper feed roller solenoid, a transport roller solenoid, and a timing roller solenoid (not shown). You. A cam in a cam mechanism (not shown) for bringing the secondary transfer roller 7 and the blade 611 into and out of contact with the intermediate transfer belt 10 is also driven at a predetermined timing by the motor M1.

Next, with reference to FIG. 2, a description will be given of a transmission mechanism for driving the above-described components by the motors M1 and M2. The power of the drive motor M1 is supplied to the gears g101 and g10.
2, g103, clutch CL1, gears g104, g10
5, g106, g107, and the photoreceptor gear g108 (gears on the axis of the photoreceptor drum 2), the gears g101, g102, g103, the clutch CL1, the gears g104, g109, g110, g111, g112 and the belt drive. Roller gear g113 (intermediate transfer unit 1)
(On-axis gear of the belt driving roller 11).

The clutch CL1 is an electromagnetic clutch in this embodiment. When the clutch is connected, the driving force is transmitted from the gear g103 to the gear g104. When the clutch is disconnected, the driving force is transmitted from the gear g103 to the gear g104. Instead, even when the motor M1 is driven, the rotation of the photosensitive drum 2 and the intermediate transfer belt 10 can be stopped. Control of connection / disconnection of the clutch CL1 is performed by a control unit CONT that controls the entire printer (see FIG. 4).

The power of the motor M1 is supplied to the gear g11.
4, g115, g116, g117, g118, g11
9, g120, g121, g122, g123 and the paper feed roller gear g124 (gear on the shaft of the paper feed roller 91). The power of the motor M <b> 1 transmitted to the gear g <b> 123 is also transmitted to the gear g <b> 125 (the gear on the axis of one of the transport roller pairs 92). The power of the motor M1 transmitted to the gear g117 is transmitted to the gears g126 and g127.
To the gear g128 (the gear on the shaft of one of the timing rollers 93).

The power of the motor M1 transmitted to the gear g116 is further transmitted via gears g129, g146, and g147 to a cam for pressing or separating the secondary transfer roller 7 and the cleaning blade 61 to or from the intermediate transfer belt 10. It is also transmitted to a gear g148 coaxial with a cam (not shown) of the device (not shown). The power transmitted to the gear g148 is transmitted to the cam device at a predetermined timing via a clutch (not shown).

The gear g129 further includes a gear g13.
The light is transmitted to a gear g149 coaxial with the drive roller 942 of the conveyor belt 941 via 0, g131, g132, and g133. From the gear g133, g135, g1
The light is transmitted to the gear g139 on the same axis as the driving roller 951 of the fixing belt 953 via the gears 36, g137, and g138. From the gear g139, it is further transmitted to a gear g150 coaxial with the oil application roller 954 via a gear g140, and also transmitted through a gear g140, g141, g142 and g143 to a gear g144 (one of the conveying roller pair 96). Gear on the shaft).

The power of the motor M1 transmitted to the gear g141 is further transmitted to the gear g145 and a pulley P902 coaxial therewith. The pulley P902, the pulley P99 (a pulley coaxial with one roller of the discharge roller pair 99), a pulley P98 (a pulley coaxial with one roller of the discharge roller pair 98), and a pulley P97 (a pulley with one roller of the discharge roller pair 97). A belt 900 is wound around a coaxial pulley, and these pulleys are driven by a belt. The pulley P901 is a tension pulley.

On the other hand, the power of the motor M2 is supplied to the gear g20.
1, g202, g203, g204, g205, g20
7, g208, and transmitted to the developing sleeve gear g209 (the gear on the developing sleeve driving roller shaft) located at the developing position, and from the gear g204 to the gear g206,
g210, g211, g212, g213, g214,
The gear is transmitted to the charging brush gear g216 (gear on the three axes of the charging brush) via g215. The gears g208 and g209 are provided in each of the developing devices (5Y, 5M, 5C and 5Bk).

As shown in FIG. 4, the motors M1 and M2 are driven and controlled by motor driving units DU1 and DU2, respectively, under the control of a control unit CONT for controlling the entire printer. Hereinafter, the operation start / stop timing of the motors M1 and M2 and the connection / disconnection timing of the clutch CL1 will be described together with the operation of full-color printing in this printer.

FIG. 3 shows a drive timing of the motor M1, a drive timing of the motor M2, an image exposure timing, a primary transfer timing, a secondary transfer timing, and a discharge when a continuous two-sheet printing process is executed in this printer. ON timing of sensor SE1, paper feed roller 9
1 is turned on at a paper feed position or a position at which paper is not fed, a solenoid is turned on at a position at which the transport roller pair 92 is placed at the paper feed position or at a position at which paper is not fed, and a timing roller pair 93 is placed at paper feed position. The ON timing of a solenoid for arranging it at a feed position or a position where paper is not fed is shown.

The printing operation is started in response to the pressing of a print start button (not shown) provided in the printer. At the start of the printing operation, the state at the end of the previous printing process is maintained.
The secondary transfer roller 7 and the blade 611 of the cleaning device 61 are separated from the intermediate transfer belt 10, and the black developing device 5Bk faces the developing position D.

First, after the clutch CL1 is disengaged, the driving of the motor M1 is started. When the rotation of the motor M1 is stabilized, the clutch CL1 is connected, and the photosensitive drum 2 and the intermediate transfer belt 10 are respectively driven in predetermined rotation directions. When the drum 2 and the belt 10 are rotationally driven, the motor M2 is subsequently driven to rotate the charging brush 3 and the developing sleeve, and the surface of the photosensitive drum 2 is sequentially charged to a predetermined potential by the charging brush 3. .

On the other hand, the developing device switching operation is started by a developing rack motor (not shown), and the developing device 5
The yellow developing device 5Y is rotated to the developing position D by being rotationally driven around a. Then, a yellow image is initially exposed on the charged photosensitive drum 2 by the laser scanning optical system 4, and an electrostatic latent image corresponding to the yellow image is formed.

The electrostatic latent image is developed by a developing sleeve 52Y rotated counterclockwise by a motor M2 when a developing bias voltage is applied. The developed yellow toner image on the photosensitive drum 2 is transferred onto the intermediate transfer belt 10 by the primary transfer roller 13 at the primary transfer portion T1. The toner remaining on the photosensitive drum 2 without being transferred to the intermediate transfer belt 10 is removed by the cleaning blade 621 of the cleaning device 62.

When the transfer of the first color (yellow) is completed,
The developing device is switched by a developing rack motor (not shown), and the developing device 5M is brought to the developing position. Then, exposure, development, and primary transfer of the magenta image are performed.
Thereafter, similarly, switching to the cyan developing device 5C, exposure and development of the cyan image, development, primary transfer, and further, the black developing device 5B
k, exposure of a black image, development, and primary transfer are performed, a toner image is superimposed on the intermediate transfer belt 10 for each primary transfer of each color, and multiple toner images are formed on the belt 10. Is done.

When the primary transfer of the last color (black) is completed, the secondary transfer roller 7 and the blade 611 are pressed against the intermediate transfer belt 10. At this time, the recording material sent out from the cassette CS by the paper feeding roller 91 placed at the recording material feeding position by the solenoid of the paper feeding roller 91 is:
Timing roller pair 9 similarly placed at the recording material feed position
3. Synchronize with the multiple toner image on the belt 10 by 2
It is sent to the next transfer section.

The multiple toner image on the intermediate transfer belt 10 is transferred onto a recording material by a secondary transfer roller 7 to which a transfer voltage is applied. The toner remaining on the intermediate transfer belt 10 without being transferred to the sheet at the secondary transfer portion is
11 and then blades 611 and 2
The next transfer roller 7 is separated from the intermediate transfer belt 10 and is prepared for the next process.

The recording material that has passed through the secondary transfer section T2 is conveyed to a fixing device 95, where the toner image is heated and fixed, and then discharged to a discharge tray TR, where the printing process for the first sheet is completed. The printing process for the second sheet has already started before the printing process for the first sheet has been completed, and similarly to the first sheet, image exposure for each color, primary transfer,
Next transfer is performed. When the secondary transfer of the last color (black) is completed, the clutch CL1 is disengaged and the drive of the photosensitive drum 2 and the intermediate transfer belt 10 is stopped. Immediately thereafter, the motor M2 is stopped to stop the rotation of the charging brush 3 and the developing sleeve.

The second recording material is a discharge sensor SE.
After it is confirmed that the vehicle has passed the front of No. 1, the drive of the motor M1 is stopped after a predetermined time has elapsed, the clutch CL1 is connected, and the printing process for two sheets continuously is completed. As described above, in the printer of the present invention, the clutch CL is provided in the path for transmitting the driving force from the motor M1 to the photosensitive drum 2.
1, the recording material conveyance system is driven,
The rotation drive of the photosensitive drum 2 can be stopped.
In this example, before the recording material is discharged, the rotation of the photosensitive drum 2 is stopped, and the rotation of the charging brush 3 and the developing sleeve are also stopped. The charging brush 3, the developing sleeve, and the cleaning blade 621 suppress unnecessary wear. In this example, the intermediate transfer belt 10 is also prevented from being unnecessarily worn by the cleaning blade 611.

After the clutch CL1 is disengaged and the driving of the photosensitive drum 2 is stopped, the driving of the motor M2 is stopped and the rotation of the charging brush 3 is stopped. The state of contact with the surface of the photosensitive drum 2 can be kept normal. More specifically, as shown in FIG. 5, the photosensitive drum 2 is rotationally driven in a normal direction (in this example, clockwise in the figure), and the charging brush 3 that contacts the photosensitive drum 2 is also rotated in a normal direction (in this example, When the photosensitive drum 2 is driven to rotate (counterclockwise in the figure), the peripheral speed of the charging brush 3 is set to be higher than the peripheral speed of the photosensitive drum 2, so that the brush bristles 3f The contacting object comes into contact with the surface of the photosensitive drum 2 as if drawing an arc flowing in the opposite direction to the rotation direction of the charging brush 3 due to contact resistance. However, for example, the brush bristles 3f of the charging brush 3 are in a state where the rotation of the charging brush 3 is stopped and only the photosensitive drum 2 is rotating.
When a contact resistance in the opposite direction to that described above is applied to the brush bristles 3f
, The contact state of the brush bristles 3f is disturbed, and it becomes difficult to charge the surface of the photoreceptor drum 2 to a predetermined potential, resulting in poor image formation. In this printer, since the charging brush 3 is stopped after the photosensitive drum 2 is stopped as described above, the brush bristles 3
f while keeping the contact state of the photosensitive drum 2
The printing process can be ended, and the photosensitive drum 2 can be charged to a predetermined potential in the next printing process. The photosensitive drum 2 and the charging brush 3 may be stopped at the same time.

Similarly, since the driving of the developing sleeve is stopped after the driving of the photosensitive drum 2 is stopped, the contact state between the developing sleeve and the photosensitive drum 2 can be maintained normally, and It is possible to prevent the problem that the slack portion is formed in the opposite direction. Incidentally, the photosensitive drum 2 and the developing sleeve may be stopped at the same time.

Further, in the printer of this embodiment, the photosensitive drum 2 and the intermediate transfer belt 10, which require smooth and stable rotation in terms of image quality, are driven by the motor M1, so that the developing sleeve and the relatively large load fluctuation can be controlled. Since the charging brush 3 is driven by the motor M2, even if the rotational load of the developing sleeve or the charging brush 3 fluctuates, the fluctuation is not transmitted to the photosensitive drum 2 or the intermediate transfer belt 10, and these are stably rotated. Can be maintained, whereby good image formation can be performed.

In the printer described above, the charging brush 3
The developing sleeve and the developing sleeve are driven by a motor M2 different from the motor M1 for driving the photosensitive drum 2 and the like, but these may be driven by one motor. FIG. 6 shows an example of such a transmission mechanism. In the power transmission mechanism shown in FIG. 6, the photosensitive drum 2, the intermediate transfer belt 10, and the recording material conveying system have a motor M as shown in FIG.
It is rotationally driven by a gear train connected to 1. In the transmission mechanism shown in FIG. 2, the charging brush 3 and the developing sleeve, which have been driven by the motor M2, are driven by the next gear train connected to the motor M1.

That is, a gear g3 is provided between the gear g130 to which the driving force of the motor M1 is transmitted and the gear g201 driven by the motor M2. The driving force is
Gear g3, gear g201, clutch CL2, gear g20
2, g203, g204, g205, g207 and g2
08 to the developing sleeve gear g209 (gear on the developing sleeve shaft), and to the charging brush gear g216 (gear on the three axes of the charging brush) via gear trains g206 and g210 to g215 connected to the gear g204. Is done. The transmission of the driving force from the gear g201 to the gear g202 can be permitted or canceled by the newly provided clutch CL2.

With such a transmission mechanism, the photosensitive drum 2, the intermediate transfer belt 10, the recording material conveying system, the charging brush 3, and the developing sleeve can be driven in the following manner as shown in FIG. Can be. That is, the motor M1
The drive start / stop and connection / disconnection are performed at the same timing as shown in FIG. 2 for the clutch CL1 and the clutch CL2. The clutch CL2 is connected at the drive start timing of the motor M2, and the motor M2 stops driving. What is necessary is just to separate at the timing which is performed.

Therefore, even in a printer having a transmission mechanism as shown in FIG. 6, unnecessary wear of the photosensitive drum 2 can be suppressed. Further, the transmission mechanism shown in FIG. 6 can reduce the number of motors as compared with the transmission mechanism shown in FIG. 2, and is advantageous in terms of cost and the like. In the above description, an example in which the present invention is applied to a full-color printer has been described. However, the present invention is also applicable to a color copying machine, a so-called monochrome printer, a copying machine, and the like.

[0056]

According to the present invention, there is provided an image forming apparatus of an electrophotographic system, wherein an electrostatic latent image carrier such as a photosensitive member driven so as to move its surface and a recording material on which a toner image is transferred are used. An image forming apparatus driven by the same drive source from the storage position to the discharge position via the transfer position, wherein the electrostatic latent image carrier is driven for image forming needs. It is possible to provide an image forming apparatus that can be driven more than necessary and can avoid a situation in which a member that comes into contact with the electrostatic latent image carrier wears more than necessary.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a full-color laser printer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a drive system for driving each section of the printer shown in FIG.

FIG. 3 is an example of a timing chart of a print process in the printer shown in FIG. 1;

FIG. 4 is a block diagram of a control system for controlling a motor and a clutch in the printer shown in FIG.

FIG. 5 is a view for explaining a state of contact of the brush bristles of the charging brush with the photoreceptor.

FIG. 6 is a diagram illustrating another example of a drive system that drives each unit of the printer illustrated in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intermediate transfer unit 10 Intermediate transfer belt 11 Belt drive roller 12 Support roller 13 Primary transfer roller 14 Tension roller 2 Photoreceptor drum 3 Rotating brush for charging 3f Brush bristles of rotating brush 3 for charging 4 Laser scanning optical system 5 Full-color developing device 500 developing rack 5Bk black developing device 50Bk black developing sleeve 5Y yellow developing device 50Y yellow developing sleeve 5M magenta developing device 50M magenta developing sleeve 5C cyan developing device 50C cyan developing sleeve 61, 62 cleaning device 611, 612 cleaning blade 7 secondary transfer roller Reference Signs List 8 separation device 91 paper feed roller 93 timing roller 941 transport belt 95 belt fixing device 92, 96, 97, 98 transport roller pair 99 discharge roller pair CS paper feed cassette T Discharge tray T1 1 transfer portion T2 2 transfer portion M1, M2 motor g101~g150, g201~g208, g3 gear CL1, CL2 clutch CONT control unit DU1, DU2 motor drive unit SE1 discharge sensor

Claims (6)

[Claims] A surface of an electrostatic latent image carrier driven so as to move is charged by a charging device, and the surface of the charged electrostatic latent image carrier is exposed to an image corresponding to a document image. Forming an electrostatic latent image, developing the electrostatic latent image with a developing device to form a toner image, and transferring the toner image to a recording material. A recording material transport mechanism configured to transport the toner image to a discharge position via a position where the toner image is transferred, wherein the electrostatic latent image carrier has a driving source and a first transmission that transmits a driving force of the driving source. The recording material transport mechanism is driven by a driving source that is the same as the driving source that drives the electrostatic latent image carrier, and is driven by a second transmission mechanism that transmits the driving force of the driving source. And wherein the first transmission mechanism is transmitted from the drive source. An image forming apparatus, comprising a drive transmission releasing mechanism way from it so as not to transmit in the preceding its transfer path power. 2. A control means for performing operation control of the drive source and drive force release control of a drive transmission release mechanism of the first transmission mechanism, the control means comprising:
2. The image forming apparatus according to claim 1, wherein the drive transmission canceling mechanism cancels the transmission of the driving force to the electrostatic latent image carrier. 3. The charging device includes a charging rotating brush that is driven to rotate while being in contact with the electrostatic latent image carrier, wherein the charging rotating brush holds the electrostatic latent image carrier. A third driving mechanism for transmitting the same driving source as the driving source to be driven and a driving force of the driving source, the driving mechanism being driven by a transmission mechanism including a driving transmission canceling mechanism; It also performs a drive transmission release control of a drive transmission release mechanism of the transmission mechanism, and simultaneously or simultaneously releases the drive transmission release to the electrostatic latent image carrier by the drive transmission release mechanism of the first transmission mechanism. The image forming apparatus according to claim 2, wherein immediately after that, the drive transmission release mechanism of the third transmission mechanism releases the transmission of the driving force to the charging rotary brush. 4. The charging device according to claim 1, wherein said charging device includes a charging rotary brush which is rotatably driven in contact with said electrostatic latent image carrier. The driving means is driven by a fourth transmission mechanism for transmitting the driving force of the driving source, and the control means also controls the operation of the charging rotary brush driving source. 3. The image forming apparatus according to claim 2, wherein the charging rotary brush driving source is stopped simultaneously with or immediately after the release mechanism releases the transmission of the driving force to the electrostatic latent image carrier. 5. The developing device according to claim 1, further comprising a developing sleeve which is in contact with said electrostatic latent image carrier and is driven to rotate, said developing sleeve being a driving source for driving said electrostatic latent image carrier. And a fifth transmission mechanism for transmitting the driving force of the driving source, which is driven by a transmission mechanism including a drive transmission canceling mechanism, wherein the control means drives the fifth transmission mechanism. It also performs drive force transmission release control of the transmission release mechanism, and simultaneously or immediately after causing the drive transmission release mechanism of the first transmission mechanism to release drive power transmission to the electrostatic latent image carrier, The image forming apparatus according to claim 2, wherein the drive transmission release mechanism of the fifth transmission mechanism releases the transmission of the driving force to the developing sleeve. 6. The developing device includes a developing sleeve which is rotated and driven in contact with the electrostatic latent image carrier. The developing sleeve supplies a developing sleeve driving source and a driving force of the driving source. The control unit also controls the operation of the developing sleeve drive source. The control unit also controls the operation of the developing sleeve drive source. 3. The image forming apparatus according to claim 2, wherein the developing sleeve driving source is stopped at the same time as or immediately after the transmission of the driving force to the carrier.