JPH09216747A - Jam disposing device in image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a paper jam disposing device and reduce a production cost. SOLUTION: Planetary gears 62, 68 are arranged movably along guide grooves 75a in the gear row of the drive system unit 6 of a rotation drive transmission for the paper sheet transfer means of a paper feed unit and a fixing unit and the planetary gears 62, 68 are meshed together in order that respective transfer means are rotated and driven in the paper sheet transfer direction at the normal rotation time of a drive motor 32 and the planetary gears 62, 68 are moved so as to release their meshing so that the transfer means can rotate freely when the drive motor 32 is reverse turned. The positions of respective planetary gears 62, 68 are held by a resistant plate 76 and an energizing spring 78 at respective positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an apparatus for processing a paper jam (jam) in an electrostatic image forming apparatus such as a copying machine, a facsimile, or a laser printer.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus of this type has a process in which a paper feeding unit for feeding paper for image formation, a photosensitive drum, a developing device for supplying toner to the photosensitive drum, and a transfer roller are incorporated. A unit, a scanner unit for forming an electrostatic latent image on a photosensitive drum, a fixing unit for heating and fixing a toner image transferred on a sheet, a drive motor for driving rotating parts in these units, and a transmission gear train. Further, it is provided with a control device and a power supply unit. Further, there are provided roller means for separating the sheets stacked in the paper feed cassette etc. one by one and conveying them to the process unit, and roller means for carrying out from the fixing device to the sheet discharge tray.

When a paper jam (jam) occurs at a portion of the roller means, a conventional one-way clutch is provided in the roller means, for example, as a jam clearance device for removing the jammed paper. If you pull the paper in the paper ejection direction, you can easily eject it,
A configuration was considered in which a torque limiter was inserted in the roller means, and when the operator pulls the paper with a tensile force above a certain level, the paper can be pulled out in that direction, but in the former configuration, the paper can be pulled out in the opposite direction. Can not. Further, in the latter configuration, a considerable pulling force is required, which makes it difficult for the operator to remove the sheet, and there is a problem that a thin sheet is torn in the middle.

Therefore, Japanese Unexamined Patent Publication No. 6-1492 discloses that
The roller means is composed of a driving roller and a nip (pressing) roller, the pressing roller is attached to an openable and closable top cover, and the operator opens the top cover when a jam occurs, so that the pressing roller is separated from the surface of the driving roller. To release the nip, open the paper transport path widely, and remove jammed paper, and provide a jam sensor to detect jams.
A configuration is disclosed in which an electromagnetic solenoid is actuated in response to a detection signal from the jam sensor to rotate the actuating arm in a direction in which the bias of the pressing roller is released.

[0005]

However, in the prior art (Japanese Patent Laid-Open No. 6-1492) where the top cover cannot be opened, there is a problem that the jam cannot be processed, while the jam sensor is used. However, there is a problem that an operating arm is required in addition to the sensor, the number of parts is increased, the size of the device is increased, and the manufacturing cost is increased.

Therefore, the present invention has been made to solve these problems, and an object of the present invention is to provide a jam processing apparatus for an image forming apparatus which has a small number of parts, a simple structure, and a low cost. It is a thing.

[0007]

In order to achieve the above-mentioned object, a jam processing device in an image forming apparatus according to a first aspect of the present invention comprises a drive motor capable of rotating in forward and reverse directions and an image forming unit including a paper feeding unit. In the image forming apparatus, the image forming apparatus is provided with a conveying unit that conveys the sheet through the sheet discharging unit via the sheet feeding unit, and a gear transmitting mechanism that transmits the rotational force from the drive forward rotation to the conveying unit. Is a planetary gear that is meshed so that the transport means is driven to rotate in the sheet transport direction when the drive motor rotates forward, and disengaged so that the transport means rotates freely when the drive motor rotates reversely. Is arranged.

The invention described in claim 2 is the same as claim 1.
In the jam processing apparatus of the image forming apparatus described in (1), the planetary gears are arranged so as to be meshed with and disengaged from at least the transmission gears to the paper feed side transport roller means and the paper discharge side transport roller means, respectively. . Further, the invention according to claim 3 is the jam processing apparatus in the image forming apparatus according to claim 1 or 2, wherein the planetary gear is configured to be movable along a guide groove provided in a frame, The frame is provided with pressing means for holding the planetary gear in its moving direction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which the present invention is embodied in a laser beam type printer will be described with reference to the drawings. FIG. 1 is a perspective view of main components of a laser printer as an image forming apparatus, and FIG. 2 is a schematic side sectional view of the laser printer. As shown in FIG. 1, the main body case 1 of the printer includes a scanner unit 2 and a process unit 3 from above.
A main frame 1a made of synthetic resin for mounting the fixing unit 4 and the paper feeding unit 5, and the main frame 1
The main frame 1a is made of synthetic resin and covers the outer surface of the four sides of a (front and rear and left and right sides), and the main frame 1a and the main cover 1b are integrally formed by injection molding or the like. The drive system unit 6 including the drive motor and the gear train is inserted from below the main body case 1 into the recess 33 between the left inner surface of the main cover body 1b in FIG. 1 and the left side of the main frame 1a adjacent thereto. And fix it. Further, the synthetic resin top cover 7 for covering the upper surfaces of the main frame 1a and the main cover body 1b has a hole 7a for penetrating the operation panel portion 1c protruding upward to the right of the main frame 1a. A hole 7b for penetrating the base of the sheet feeding unit 5 is formed. The base of the paper discharge tray 8 is mounted on brackets 9 and 9 (only one of which is shown in FIG. 1) protruding from the left and right sides of the front end of the top cover 7 so as to be vertically rotatable. The paper discharge tray 8 can be folded and covered on the upper surface side of the top cover 7.

In the stacked state, the leading end side of the sheets P set in the feeder case 5a of the sheet feeding unit 5 is attached to the sheet feeding roller 11 by the support plate 10 with the biasing spring 10a in the feeder case 5a. The sheets are separated one by one by the sheet feed roller 11 and the separation pad 12 which are pressed toward each other and are rotated by the power transmitted from the drive system unit 6.
The separated sheet P is placed on a pair of upper and lower registration rollers 13,
The paper P that has been fed to the process unit 3 at 14 and has an image formed with toner on the surface at the process unit 3 has the heating roller 15 and the pressing roller 1 of the fixing unit 4.
The image is fixed at 6 and then discharged to the paper discharge tray 8.

An upper support plate 2a of the scanner unit 2 is provided at a lower portion of the process unit 3 which is arranged substantially in the center of the main frame 1a having an open upper surface of the body case 1 in plan view. The scanner unit 2 is fixed to a stay portion integrally formed on the upper surface side of the bottom plate portion with screws or the like. In the scanner unit 2, a laser emitting portion and a polygon mirror are provided on the lower surface side of an upper support plate 2a made of synthetic resin. 18, a lens 19, a reflecting mirror 20 and the like are arranged, and the process unit 3 is passed through a glass plate 21 that covers a horizontally long scanner hole formed in the upper support plate 2a so as to extend along the axis of the photosensitive drum 17. The outer peripheral surface of the photoconductor drum 17 is irradiated with a laser beam for exposure.

As shown in FIG. 2, the process unit 3 includes the photosensitive drum 17, a transfer roller 22 in contact with the upper surface thereof, a charging device 23 of a scorotron type or the like arranged below the photosensitive drum 17, and a charger. A developing device arranged upstream of the photosensitive drum 17 in the paper direction, a developer (toner) supply unit, that is, a detachable toner cartridge 24 arranged upstream thereof, and a downstream of the photosensitive drum 17. The cleaning device 25 and the like. An electrostatic latent image is formed on the outer peripheral surface of the photoconductor drum 17 by scanning the charged layer formed by the charger 23 with a laser beam from the scanner unit 2. Developer (toner) in the toner cartridge 24
Is discharged by being stirred by a stirring member 28, and then carried on the outer peripheral surface of the developing roller 27 via the supply roller 26,
The thickness of the toner layer is regulated by the blade. The electrostatic latent image on the photoconductor drum 17 is visualized by the developer adhering from the developing roller 27, and is transferred onto the sheet P passing between the transfer roller 22 and the photoconductor drum 17. Then, the toner remaining on the photosensitive drum 17 is collected by the cleaning device 25.

The process unit 3 is made into a cartridge by being incorporated in a case 29 made of synthetic resin, and the cartridge-shaped process unit 3 is detachably mounted on the main frame 1a. Also,
A downward facing rib 7 is provided on the lower surface of the synthetic resin top cover 7.
1 is provided so that the rib 71 faces the upper surface of the conveyance path of the sheet P from the registration roller pair 13 and 14 in the sheet feeding unit 5 to the transfer roller 22 in the process unit 3 so that the chute of the sheet P is formed. I have to. Therefore, when a paper jam occurs, the jammed paper P can be easily removed simply by removing the top cover 7.

FIG. 3 shows a drive mechanism by means of a gear train for each unit, and a part of this drive mechanism is collectively arranged on the left side of the main body case 1 of the printer as a drive system unit 6 as described later. ing. That is, the rotational force of the pinion gear 32a of the drive motor 32, which is fixed to the drive system unit 6 and can rotate in the forward and reverse directions, is equal to the two-stage gear 60.
(60a, 60b) and two-stage gear 61 (61a, 61b)
Via the gear 62, two-stage gear 63 (63a, 63b)
To the gear 11a that drives the paper feed roller 11 in the paper feed unit 5. The gear 63
The rotational force of the resist roller 13 is transmitted through the transmission gear 80.
Is transmitted to the gear 13a.

The rotational force of the two-stage gear 60 (60a, 60b) is the same as that of the three-stage gear 64 (64a, 64b, 64c).
Two-stage gear 65 (65a, 65b), two-stage gear 66 (66
a, 66b) and is transmitted to the gear 17b of the photosensitive drum 17 via the two-stage gear 67 (67a, 67b). Further, the rotational force of the two-stage gear 67 (67a, 67b) is transmitted to the gear 15a of the heating unit 15 of the fixing unit 4 via the gear 68 and the two-stage gear 69 (69a, 69b).

On the other hand, the rotational force of the two-stage gear 65 (65a, 65b) is transmitted to the agitator 28 via the gears 81, 82, 83, while it is transmitted through the gears 81, 84, 85 to the supply roller 26 and the developing device. It is transmitted to the roller 27. The frame 600 made of synthetic resin of the drive system unit 6 includes the drive motor 32, the pinion gear 32a, and the two-stage gears 60, 6
1, 63, 65, 66, 67, 69 and three-stage gear 64,
Gears 62 and 68 are incorporated.

Next, the integral construction of the main frame 1a and the main cover 1b will be described in detail with reference to FIGS. FIG. 4 is a schematic plan view of the main body case 1, and the main cover body is arranged so as to be continuously provided outside the four circumferences of the main frame 1a having a substantially rectangular upper surface open box shape located in the central portion of the main body case 1 in plan view. 1b is formed, and the left and right shaft portions 17a of the photoconductor drum 17 in the process unit 3 are fitted into the right side portion 1a-1 and the left side portion 1a-2 of the main frame 1a in plan view from above. Grooves 31, 31 are formed. Further, an operation panel portion 1c is formed in the front half of the right side portion 1a-1, and a storage recess 3 into which the drive system unit 6 is fitted from below and attached to the left side portion 1a-2.
3 is formed, and a part thereof has open hole portions 34, 35, 36, 37 for exposing the two-stage gears 63, 65, 67, 69 which are transmission portions to each unit (see FIG. 6 and (See FIG. 7). The lower surface side (inner surface side) of the storage recess 33
A stay for fixing the frame 600 of the drive system unit 6 integrally projects downward.

The lower surface side of the main frame 1a, which is continuous with the rear portion 1a-3 and the rear surface of the main cover body 1b, has a drive motor 3 in the drive system unit 6.
2 and the power supply unit 40 are accommodated (see FIG. 6).
Further, a storage portion 42 for storing the cooling fan 41 and a paper P are provided on the lower surface side of the main frame 1a, which is continuously provided by the front portion 1a-4 and the front surface of the main cover body 1b.
And a ventilation duct 43 extending in a direction orthogonal to the passing direction of the above. In this case, the upper surface plate portion 43a of the ventilation duct 43 is formed in a substantially V shape with a downward cross section, and the upper surface plate portion 43a is located between the process unit 3 and the fixing unit 4 arranged on the upper surface side of the main frame 1a. Thus, the radiant heat from the heating roller 15 in the fixing unit 4 is prevented from being transmitted to the process unit 3 side (see FIGS. 2, 4, and 6). As shown in FIGS. 2 and 6, a partition plate 44 made of metal is continuously provided between lower ends of the upper surface plate portion 43a having a downward V-shaped cross section, and a portion surrounded by these members is a ventilation duct. 43, cooling fan 41
Is configured to pass the cooling air from.

The bottom plate portion 1a-of the main frame 1a
5, while supporting the scanner unit 2, the bottom plate portion 1
Part of the lower surface side of a-5 (left side part 1a-2 side part)
And a bottom plate 45 made of metal that fits and closes the lower ends of the front and rear sides of the main cover body 1b to form a ventilation path 46 that communicates with the space in which the drive motor 32 and the power supply unit 40 are housed. An air introduction port 47 and an exhaust port 48 are provided on the front side and the rear side of the body 1b, respectively.

Next, the structure of the drive system unit 6 will be described in detail with reference to FIGS. FIG. 7 shows a state in which the drive system unit 6 is fitted in the housing portion 33, and the frame 600 made of synthetic resin in the drive system unit 6 has a side (power) on which the drive motor 32 is mounted as shown in FIG. The stepped portion 600 is provided between the wide surface of the board portion 600a in the upstream portion of the transmission and the wide surface of the board portion 600b in the downstream portion of the transmission.
c, and a plurality of gear shafts 601, 602, 603 (representative gear shaft 601 is shown in FIG. 9) in the base plate portion 600a at the transmission upstream side) have their free ends on the drive motor 3 side.
2 protruding in the mounting direction of the base plate 6 of the transmission downstream side portion
00b multiple gear shafts 604, 605, 606, 6
07 and 608 are integrally molded so that their free ends project in the opposite direction (toward the main cover body 1b).

Around the board portions 600a and 600b, peripheral side plate portions 600d are integrally projected so that the frame 600 is formed in a box shape. Then, after fitting the gears corresponding to the respective gear shafts, the respective gear shafts 6
Support metal plate 7 having holes into which free ends 01 to 608 fit
2, 73 are opposed to the wide surfaces of the substrate parts 600a and 600b, and are locked by a plurality of locking claws 74 elastically provided on the peripheral side plate part 600d (FIGS. 10 and 1).
2). In addition, the support metal plate 7 for the upstream portion of the transmission
The drive motor 32 is fixed to 2.

Next, the paper jam clearance mechanism will be described with reference to FIGS. 7, 8, 11 and 12. In the paper jam processing mechanism of the present invention, during normal image formation (print processing), the drive motor 32 is applied to the gear on the roller side, which is the paper transporting means of the paper feeding unit 5 and the fixing unit 4 which is the paper discharging unit. The planetary gears are held in a meshed state so as to transmit the rotational driving force from. On the other hand, when a paper jam occurs and the operator removes the jammed paper, it is a mechanism for separating the planetary gear from the gear on the roller side of the conveying means and disengaging the planetary gear. The gear 62 that can be brought into contact with and separated from the driven gear 63a and the gear 68 that can be brought into and out of contact with the gear 69a of the two-stage gear 69 that is transmitted to the gear 15a that drives the heating roller 15 of the fixing unit 4 are idle gears.

The planetary gear 62 can be rotated by an appropriate distance along the outer circumference of the drive side gear 61b, and the planetary gear 68 can be rotated by an appropriate distance along the outer circumference of the drive side gear 67a. In addition, the board portions 600a and 600b are provided with guide grooves 75a and 75a, and the supporting metal plates 72 and 73 are provided.
Are provided with guide grooves 75b and 75b in an arc shape concentric with the rotation centers of the gears 61b and 67a, respectively, and the shaft portions 62a (68a) of the planetary gears 62 and 68 move along the guide grooves 75a and 75b. (See FIGS. 8, 9 and 11). Instead of this,
The planetary gears 62, 68 may be rotatably mounted on a rotating arm (not shown) around the rotation center of the gear 61b and the gear 67a.

Then, as shown in FIGS. 11 and 12 which are representatively shown on the side of the sheet feeding unit 5, the substrate portion 600a is for holding the state in which the planetary gear 62 is moved in the meshing direction or the meshing releasing direction. As the pressing means, a resistance plate 76 that comes into contact with the tooth surface or the outer peripheral surface of the planetary gear 62 and a spring piece 77 having a U-shaped cross section that is continuously provided at the front and rear ends of the resistance plate 76 are integrally formed. The bias spring 78 is inserted.
In this case, the U-shaped spring pieces 77 at both ends also have a function of holding the resistance plate 76 in a posture that does not change extremely.

With this configuration, when the drive motor 32 is operated in the forward rotation direction during image formation, as shown in FIG. 8, the pinion gear 32a rotates counterclockwise, and the gear 61b rotates counterclockwise via the two-stage gear 60. Since it rotates clockwise, the planetary gear 62 that is always meshed with this gear 61b
Rotates in the clockwise direction and approaches and meshes with the driven gear 63a on the sheet feeding unit 5 side. As a result, the rotational force of the drive motor 32 is transmitted to the sheet feeding unit 5, and the sheet feeding roller 11 and the registration roller 13 are rotationally driven, so that the sheet feeding operation can be executed. At this time, since the outer peripheral surface of the planetary gear 62 is in contact with the resistance plate 76 and is pressed by the biasing spring 78 or the like to maintain the meshing posture, even if the drive motor 32 is temporarily stopped, the image forming work is performed. Even when the above is restarted (when the drive motor 32 is restarted), the rotational force of the drive motor 32 can be immediately transmitted to the sheet feeding unit 5 side.

On the other hand, on the fixing unit 4 side at the time of image formation, as shown in FIG. 8, the gear 67a of the two-stage gear 67 rotates clockwise, and the planetary gear 68 constantly meshed with the gear 67a is reversed. While rotating clockwise, it approaches the gear 69a of the two-stage gear 69 for transmission to the fixing unit 4 and meshes with it. As a result, the rotational force of the drive motor 32 is transmitted to the fixing unit 4, and the heating roller 15 can be rotated clockwise in FIG.

When the jammed paper P is removed and the jammed paper P is removed, as shown in FIG. 9, the drive motor 32 is used.
Reverse rotation is performed by a fixed amount. As a result, the pinion gear 32a rotates clockwise in FIG. As a result, the gear 61b rotates clockwise through the two-stage gear 60. The planetary gear 6 that is always meshed with the gear 61b
2, while rotating in the counterclockwise direction, revolves away from the gear 63a and is disengaged. The disengagement posture is such that the resistance plate 76 that contacts the outer peripheral surface of the planetary gear 62.
It is held by the biasing spring 78. Therefore, the paper feed roller 11 and the registration rollers 13, 1 in the paper feed unit 5 are
4 does not rotate, and if the operator pulls the paper P meshed with these roller portions, the paper feed roller 1
Since the 1 and the registration rollers 13 and 14 can freely rotate, the paper P can be easily pulled out.

Similarly, as shown in FIG. 9, when removing the jammed paper P, the drive motor 32 is operated as described above.
Is reversely rotated by a predetermined amount, the gear 67a of the two-stage gear 67 on the fixing unit 4 side rotates counterclockwise, and this gear 6
The planetary gear 68, which is always in mesh with 7a, revolves clockwise while revolving away from the gear 69a of the transmission two-stage gear 69 to the fixing unit 4, and is disengaged. As a result, the rotational force of the drive motor 32 is not transmitted to the fixing unit 4, the heating roller 15 stops, and the heating roller 15 and the pressing roller 16 can freely rotate. Therefore, if the operator pulls the jammed paper P at the fixing unit 4 in the paper discharge direction or the like, the paper P can be easily removed.

In order to remove the jammed paper P generated in the process unit 3, the gear 65b meshing with the gear 81 on the process unit 3 side shown in FIG. 3 has an appropriate rotation angle (for example, 120 degrees). If you add another gear that is free, the photosensitive drum 17 and the transfer roller 2
The operator can pull out the sheet P caught between the sheet P and the sheet 2.

As described above, the drive system unit 6 is provided with the planetary gears which are movable in the meshing and disengaging directions, and the jamming process is performed by rotating the drive motor 32 in the reverse direction by a predetermined amount. The sheet conveying means such as the fixing unit 4 can freely rotate. The jam processing device having this configuration can be easily incorporated in the gear train of the drive system unit 6 and requires a separate drive means such as a conventional mechanism for releasing the pressing force of the conveying means (roller). Therefore, the structure is extremely simple, inexpensive, and compact.

Further, if the supporting metal plates 72, 73 and the frame 600 are formed with guide grooves and the frame 600 is provided with the pressing plate 76, the planetary gear 6 can be easily constructed.
The mechanism for moving 2, 68 and maintaining the meshing position and maintaining the meshing disengagement position can be made extremely simple. Further, the jam processing can be controlled extremely simply because the jam processing can be performed only by the operation direction of the drive motor, that is, the drive motor that rotates normally during image formation is rotated in the reverse direction.

According to the present invention, a separate discharge roller pair is provided on the downstream side of the fixing unit in the conveying direction, and the planetary gears are disengaged so that the roller pair can be freely rotated during the jam processing. It goes without saying that the present invention can also be applied to a form in which a gear transmission mechanism is incorporated in a main frame made of metal plate or the like.

[0033]

As described above, the jam processing apparatus in the image forming apparatus according to the first aspect of the present invention includes the drive motor capable of rotating in the normal and reverse directions, and the paper discharge unit to discharge the paper. In an image forming apparatus, which is provided with a conveying unit that conveys a sheet across a unit, and a gear transmission mechanism that transmits the rotational force from the drive forward rotation to the conveying unit,
In the gear transmission mechanism, when the drive motor rotates forward, the conveying means engages so as to rotate and drive in the sheet conveying direction, and when the drive motor rotates reversely, the conveying means disengages so as to rotate freely. It has a movable planetary gear.

Therefore, a planetary gear that is movable in the meshing and disengaging directions is arranged in the gear transmission mechanism, and when the jam is cleared, the drive motor is reversely rotated by a predetermined amount.
The sheet conveying means such as the sheet feeding unit and the fixing unit can freely rotate. The jam processing device having this configuration can be easily incorporated in an arbitrary gear train of the gear transmission mechanism, and a separate driving means such as a conventional mechanism for releasing the pressing force of the conveying means (roller) is used. Since it is not necessary, the structure is extremely simple, inexpensive, and compact.

The invention described in claim 2 is the same as claim 1
In the jam processing apparatus of the image forming apparatus described in (1), the planetary gears are arranged so as to be meshed with and disengaged from at least the transmission gears to the paper feed side transport roller means and the paper discharge side transport roller means, respectively. . As described above, even if the planetary gears are arranged so as to engage and disengage at least two transmission gears separated from each other at least on the paper feed side and the paper discharge side, these planetary gears have one drive motor. Since it can be moved in a predetermined direction by the normal rotation operation and the reverse rotation operation, it is not necessary to dispose the driving means at each jam processing position, and the manufacturing cost can be reduced and the jam processing apparatus can be made more compact. .

Further, the invention according to claim 3 is the jam processing apparatus in the image forming apparatus according to claim 1 or 2, wherein the planetary gear is movable along a guide groove provided in the frame. The frame is provided with a pressing means for holding the planetary gear in its moving direction. Therefore, the mechanism for orbital movement of the planetary gears and the position holding mechanism for the meshing position and the meshing releasing position have a simple structure, and the effect of improving the assemblability of the jam handling device and reducing the manufacturing cost is achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of main components of a laser printer.

FIG. 2 is a schematic sectional view of a laser printer.

FIG. 3 is a diagram of a power transmission mechanism to each unit.

FIG. 4 is a plan view of a main body case.

FIG. 5 is a side view taken along a line VV in FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;

FIG. 7 is a sectional view taken along line VII-VII of FIG. 4;

FIG. 8 is a diagram showing a meshing state of planetary gears in a drive system unit during normal rotation.

FIG. 9 is a diagram showing a meshing state of planetary gears in a drive system unit during reverse rotation.

10 is an enlarged cross-sectional view of the frame of the drive system unit, which is taken along the line XX in FIG.

FIG. 11 is a partially enlarged side view of the drive system unit on the paper feed side.

12 is a sectional view taken along line XII-XII of FIG.

[Explanation of symbols]

 P Paper 1 Main body case of laser printer 1a Main frame 1b Main cover 2 Scanner unit 3 Process unit 4 Fixing unit 5 Paper feeding unit 6 Drive system unit 11 Paper feeding roller 15 Heating roller 32 Drive motor 60-69, 80-85 Gear 62,68 Planetary gear 600 Frame 72,73 Support metal plate 75a, 75b Guide groove 76 Resistance plate 77,77 Spring piece 78 Energizing spring

Claims (3)

[Claims] 1. A drive motor capable of rotating in the normal and reverse directions, a conveying unit for conveying a sheet from a sheet feeding unit to a sheet discharging unit via an image forming unit, and a rotational force from the driving forward rotation to the conveying unit. In an image forming apparatus including a gear transmission mechanism for transmitting, in the gear transmission mechanism, when the drive motor rotates forward, the conveying means meshes so as to rotate and drive in the sheet conveying direction, and reverse rotation of the drive motor. A jam processing apparatus in an image forming apparatus, wherein a planetary gear that is movable so as to be disengaged so that the transporting means can freely rotate is arranged. 2. The planetary gear is arranged so as to be meshed with and disengaged from at least a transmission gear to the paper feed side transport roller means and the paper discharge side transport roller means, respectively. Jam processing device in the image forming apparatus. 3. The planetary gear is configured to be movable along a guide groove provided in a frame, and the frame is provided with a pressing means for holding the planetary gear in its moving direction. The jam processing device in the image forming apparatus according to claim 1.