JPH06250470A - Supporting mechanism for paper feed part in image forming device - Google Patents

Abstract

PURPOSE:To easily and surely lock or unlock a supporting part in a state where a feed part unit is positioned at a specified position in the case of moving the feed part unit between an actuating position and a retreating position. CONSTITUTION:The feed part unit for paper 1 is provided to be rocked and displaced between the actuating position and the retreating position with respect to a photosensitive drum 2. A supporting link mechanism 4 holding the unit 1 at the actuating position with respect to the photosensitive drum 2, and a pressing means 3 pressing the unit 1 between the actuating Position and the retreating position are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for supporting a sheet feeding section from a sheet feeding section of an image forming apparatus to a fixing position of an image transferred onto the sheet, and more particularly to a tractor section and a transfer section. Also, a support mechanism for arranging the suction feeder portions at a predetermined interval and vertically moving the support body from a predetermined position to a reset state by a link mechanism and accurately and fixedly held in a set state is a support mechanism for a sheet conveying unit in an image forming apparatus. It is about.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer or a copying machine, an electrostatic latent image formed on a photosensitive drum is transferred to a sheet in order to transfer a visible image formed by development with toner or the like onto a sheet. It is necessary to position the transfer portion with respect to the photosensitive drum with a considerably high dimensional accuracy. At the same time, the paper must be stably moved to a fixing unit for fixing the image transferred on the paper. From such a thing,
Since the transfer section and the photosensitive drum are in close contact with each other and the sheet passes between them, the vicinity of the transfer section is structurally narrow.

Therefore, at the time of inspecting and cleaning each operation section and the transfer section for forming an image disposed around the photosensitive drum, the transfer section is separated from the photosensitive drum and the work can be performed without damaging each section. Need to be able to. In addition, it is necessary to retract the transfer unit for the jam processing that occurs during operation, and it is required to make the distance between the photosensitive drum and the paper path as wide as possible in order to perform the processing. It For this reason, conventionally, the unitized transfer portion is generally retracted from the photosensitive drum to form a space.

[0004]

However, in the image forming apparatus using continuous paper, since the paper to be supplied is a series from the tractor unit to the fixing unit to the stacker unit, the space between the photosensitive drum and the transfer unit is the same. In order to open it, it is necessary to retreat the transfer part considerably. This means that the amount of displacement is large, so it is important to be able to reliably restore the set position when setting the transfer part to an operable state, and it is easy to return from the set state to the reset state and then to the set state again. Required to be present.
In addition, the structure of these operation units must be configured without complicating.

In view of such a situation, the present invention, when moving the transport unit that also supports the tractor section and the suction feeder section located in front of and behind the transfer section together with the transfer section, between the operating position and the retracted position. Another object of the present invention is to provide a support mechanism for a sheet transporting unit that is configured to lock or unlock the supporting unit while being positioned at a predetermined position.

[0006]

A support mechanism for a sheet conveying section according to the first aspect of the present invention, which is configured to achieve such an object, is shown by the principle configuration diagram of the first aspect of the present invention in FIG. As described above, the paper transport unit (1) is provided so as to be capable of swinging displacement with respect to the photosensitive drum (2) between an operating position and a retracted position, and the transport unit ((1) for the photosensitive drum (2) is provided. A support link mechanism (4) for holding 1) in the operating position, and a biasing means (3) for biasing the transport unit (1) between the operating position and the retracted position. It is a feature.

In such a support mechanism for the sheet transporting unit of the present invention, the transporting unit (1) includes a tractor unit for feeding a sheet, a transfer unit, and a suction feeder unit for holding and transporting the sheet. It is preferable that a transport frame that supports these in an array is pivotally supported on the machine body at the sheet feeding side end. A torsion coil spring is used as the urging means (3) for urging the transfer unit (1),
It is preferable that the movable operation portion by the torsion coil spring is movably abutted so as to face the pivot side of the transport unit (1). A support spring base is attached to the torsion coil spring as a movable operation portion, and a roller is attached to the tip end of the support spring base to facilitate the displacement of the support member of the transport unit (1). By doing so, smooth urging can be performed.

The transport unit (1) is connected to at least a pair of support link mechanisms (4) at its movable end so that it can be oscillated and displaced with respect to the photosensitive drum (2) between an operating position and a retracted position. The link support portion on the fuselage side is movably mounted so that the link support portion is supported and set at a prescribed position by the positioning means, and the intermediate coupling portion of the support link mechanism is held at a position beyond the dead point line. preferable. Further, in the link support portion on the machine side of the support link mechanism (4), the fulcrum support spring is brought into contact with the link fulcrum shaft on the side acting on the lifting reaction force so that the intermediate connecting portion of the link mechanism forms a dead point line. It is preferable to set the supporting force of the fulcrum shaft so that it is movable only when the fulcrum is crossed.

Next, the support mechanism for the sheet conveying section of the second aspect of the present invention, as shown in the principle configuration diagram of the second aspect of the present invention of FIG. 2, sets the sheet conveying section unit (1) to the photosensitive drum. An operation handle mechanism (5) connected to a support link mechanism (4) for swinging and displacing the operation handle and the retracted position with respect to (2) is provided on the outside of the machine body, and the operation handle mechanism (5) is provided. In the movable base portion and the machine body side facing the movable base portion, a lock releasing means for releasing the locked state by the support link mechanism (4) when the transport unit (1) is reset from the operating position to the retracted position ( 6) is provided.

The operation handle mechanism (5) according to the present invention comprises a lever of a required length whose base end is fixed to the fulcrum shaft of the support link mechanism (4) outside the machine body, and a tip portion of the lever. The transport unit (1) by the support link mechanism (4) is provided with a handle to which the backbone is pivotally attached and is attached so as to be able to be tilted, and a release part of the lock releasing means (6). This is a desirable configuration because it is easy to move from the operating position to the retracted position or vice versa. It is preferable that the lever of the operation handle mechanism (5) has its base end fixed to the fulcrum shaft in a posture facing the lower link of the support link mechanism (4).

As the unlocking means (6), the operation handle mechanism (5) is set in the operating position of the transport unit (1) by the support link mechanism (4), and the operation handle mechanism (5) is used. A cam provided on the outer surface of the fuselage side facing the pivot portion of the lever and the handle of
The support link mechanism is constituted by a releasing part piece attached to the main part of the handle so as to face the cam, and the releasing part piece is engaged with the inclined surface of the cam by the raising operation of the handle. It is desirable that the locking force acting on the fulcrum shaft of 4) can be released to displace from the operating position to the retracted position over the dead point line.

[0012]

In the first aspect of the present invention having the above-described structure, the paper feed tractor portion provided in the sheet conveying path, the transfer unit, and the suction feeder portion for transferring the transferred sheet to the fixing position are provided. The carrier unit (1) is supported in a predetermined arrangement and is urged by the support link mechanism (4) so that the carrier unit (1) can be always kept at the operating position with respect to the photosensitive drum (2). In order to release this state and perform cleaning or jam processing, the transport unit (1) is displaced to the retracted position by operating the support link mechanism (4) supported at one end of the transport unit. Thus, a space can be easily formed between the photosensitive drum (2) and the photosensitive drum (2). Then, in order to return the transport unit (1) to the operating position, its movement is facilitated by the urging means (3), and the support link mechanism (4) supports it beyond the dead point line. Each part mounted on the transport unit (1) is correctly maintained in the operating position.

The transport unit (1) is pivotally supported by the machine body at the sheet feeding side end and is supported at the other end side by a support link mechanism (4) so as to be displaceable between an operating position and a retracted position. A movable operation portion, which is a torsion coil spring and is used as a biasing means (3) for biasing the transport unit (1) to be moved to an operating position, is directed toward the pivot side of the transport unit (1). By making contact with each other, the urging force of the urging means (3) at the time of returning from the retracted position to the operating position can be increased as it approaches the specified position, which facilitates the moving operation. If a support spring base is attached to the torsion coil spring as a movable operation unit and a roller is attached to the tip end of the support spring base and brought into contact with the support member of the transport unit (1), the displacement can be changed. It will be easier.

The carrier unit (1) is movably supported by the support link mechanism (4) connected to the movable end of the carrier unit so that the carrier unit (1) can be displaced between the operating position and the retracted position. When held in the position, the connecting portion of the support link mechanism is held at a position beyond the dead point line. This support link mechanism (4)
Since a fulcrum shaft support spring is provided on the link support portion on the machine side on the side where the reaction force is lifted with respect to the fulcrum shaft of the link, when returning the transport unit (1) to the operating position,
It is possible to cross the dead point line by overcoming the pushing force of the fulcrum support spring and lowering the fulcrum shaft of the link that was kept in a steady position until it crossed the dead point line at the connection part of this support link mechanism (4). ,
After that, the fulcrum supporting spring holds the spring without pushing back due to the pushing-up force.

Since the support link mechanism (4) is configured as described above, it is possible to give a click feeling to the hand to be operated when the transport unit (1) is set to the operating position, so that the reliability of the operation can be obtained. . Further, the support link mechanism (4)
Can be operated without any trouble because the positioning means holds the specified position with respect to the photosensitive drum (2) in advance against the displacement when crossing the dead point line.

Next, in the above-described second invention, an operation connected to the support link mechanism (4) for displacing the transport unit (1) with respect to the photosensitive drum (2) between the operating position and the retracted position. A handle mechanism (5) is provided on the outside of the machine,
The movable base portion of the operation handle mechanism (5) and the machine body side facing the movable base portion are locked by the support link mechanism (4) when the transport unit (1) is reset from the operating position to the retracted position. Since the lock releasing means (6) for releasing the lock is provided, the transport unit (1) cannot be moved to the retracted position unless the lock releasing means (6) is operated by the operation handle mechanism (5). . In other words, if the operation handle mechanism (5) is kept in a predetermined posture after the transport unit (1) is set, the transport unit (1) is locked in the operating position.

When the operation handle mechanism (5) is in a state in which it can be operated by raising a handle which is attached to the tip end of a lever whose base end is fixed to a fulcrum shaft of the support link mechanism (4), the handle can be raised. The unlocking piece of the unlocking means (6) provided on the main part of the handle comes into contact with the slope of the cam attached to the aircraft body at the opposite position, so that the operation handle is operated by this cam through the unlocking piece. The mechanism (5) is guided and displaced so as to slide down. Therefore, the supporting link mechanism is acted so as to momentarily push down the fulcrum shaft against the holding force of the fulcrum supporting spring acting on the fulcrum shaft of the supporting link mechanism (4) connected to the operation handle mechanism (5). The operation can be performed over the dead point line of (4), and the transfer unit (1) can be easily moved to the retracted position.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of a support mechanism for a sheet conveying section in an image forming apparatus according to the present invention will be described with reference to the drawings.

FIG. 3 is a schematic configuration diagram of the main parts of the image forming apparatus to which the support mechanism of the sheet conveying section according to the embodiment of the present invention is applied.
Indicated by. As shown in the figure, the image forming apparatus according to the present exemplary embodiment includes a pre-charging device 12 that uniformly charges the surface of the photosensitive drum 11 and a portion of the surface of the photosensitive drum 11 charged by the pre-charging device 12 other than the image portion. To form an electrostatic latent image, and a toner image having a polarity opposite to that of the electrostatic latent image is attached to the electrostatic latent image formed by the optical portion 13 to form a visible image. Developing unit 14 for
A sheet (recording sheet) A is superposed on the toner image formed by the developing unit 14, and a charge having a polarity opposite to the charge polarity of the toner is applied to the sheet A from the back side of the sheet A to form the toner image by electrostatic force. A transfer guide section 15 for transferring onto the sheet A and a fixing section 1 for permanently fixing the toner image transferred onto the sheet A by fusing the sheet A with heat or pressure.
6, a cleaner unit 17 for removing residual toner remaining on the photosensitive drum 11 without being transferred, a tractor unit 18 and a suction feeder provided on the upstream side and the downstream side of the photosensitive drum 11 for conveying the sheet A, respectively. And a section 19.

As shown in FIG. 4, the transport unit 20 of this embodiment includes the transfer guide unit 15 and the front and rear positions thereof, that is, the tractor unit 18 disposed on the downstream side and the upstream side of the photosensitive drum 11, respectively. Suction feeder section 19
Are arranged and supported on a single carrier frame 21, and are pivotally supported by a support shaft 22 on a machine frame 24 located outside at the end of the carrier frame 21 on the side supporting the tractor portion 18. The transport unit frame 21 is formed by arranging two plates in parallel at a required interval, and in the widthwise direction (in the drawing, by a supporting member of the transfer guide unit 15, the tractor unit 18, and the suction feeder unit 19) at an intermediate portion. (Direction orthogonal to the figure).

The transfer guide portion 15, the tractor portion 18, and the suction feeder portion 19 are provided on the movable end portion 21 'opposite to the pivotal support portion of the transport portion frame 21 at required positions from the operating position with respect to the photosensitive drum 11. A support link mechanism 25 is connected to a retracted position for forming a space away from the support link mechanism so as to be displaceable. This support link mechanism 25
Is a set of two links 25a and 25b, and the intermediate connecting pin 25
They are connected by d and are symmetrically arranged on both sides of the transport frame 21 (see FIG. 7), and the upper end of the upper link 25a (hereinafter referred to as the upper link) is pin 25 on the upper portion of the transport frame 21.
The lower end of the lower link 25b (hereinafter referred to as the lower link) is connected to the machine frame 24 by a link fulcrum shaft 26 that is supported so that both ends thereof can be vertically moved by an appropriate amount. In this specific example, the lower link 25b is slightly shorter than the upper link 25a.

In this support link mechanism 25, as shown in FIG. 4, the intermediate connecting pin 25d has the intermediate frame connecting pin 25d in the state where the carrier frame 21 is set to the operating position.
The lower link 25b is brought into contact with the stopper 27 at a position beyond the straight line b (dead point line) connecting the position of the pin 25c connected to the center of the fulcrum shaft 26 connected to the body frame 24 side in the direction of arrow B. It is held so that it does not go back unless a return operation is performed.

The fulcrum shaft 26 of the support link mechanism 25
At the front side position (the right side position in the drawing) of the fulcrum support spring 28, the base end portions of the fulcrum support springs 28 are fixed to the lateral members 24a installed between the insides of the body frame 24. It is pressed against the lower side of the fulcrum shaft 26 and is urged so as to be constantly pushed upward.

Further, a pushing-up means 30 for pushing up and urging the carrier frame 21 in the operating position direction is provided at an upper position of the fulcrum support spring 28 via a supporting lateral member 24b mounted on the lateral member 24a. As shown in FIG. 5, the push-up means 30 is provided with a support lateral member 24.
The mounting plate 31 to be fixed to b and the both ends in the width direction (vertical direction in the drawing) are bent at right angles at one end of the mounting plate 31 in the length direction (horizontal direction in the drawing). Movable spring base 3 pivotally connected to each other by a shaft 33 at its ends
2 and a torsion coil spring 34 interposed between the movable spring base 32 and the mounting plate 31. In this torsion coil spring 34, one of the spring movable portions 34b and 34c, which fits the coil portion 34a of the base portion on the shaft 33 and projects in two directions at an appropriate angle, follows the upper surface of the mounting plate 31, and the other spring The movable portion 34c is brought into contact with the lower surface of the movable spring base 32, and the movable spring base 32 is configured to rotate in a direction in which the movable spring base 32 is lifted up with respect to the shaft 33. In addition, the movable tip portion 3 of the movable spring base 32
2 '(movable operation part) is bent at a substantially right angle to be reinforced, a plurality of brackets 35 are attached to the corners of this movable tip part 32' at appropriate intervals, and a roller 36 is supported by a shaft 36a supported by these brackets 35. Are attached respectively. Reference numeral 37 in the figure denotes two torsion coil springs 3.
It is a piece that blocks the movement of 4, 34 along the axis 33. Note that FIG. 5B shows the torsion coil spring 3 for convenience of illustration.
One movable end 34c of No. 4 is shown in a free state.

As shown in FIG. 4, the pushing-up means 30 is attached so that the movable tip portion 32 'of the movable spring base 32 is positioned so as to face the support shaft 22 of the carrier frame 21. A plurality of rollers 36 arranged on the movable tip portion 32 ′ of the movable spring base 32, which is pushed up by the torsion coil spring 34, are constantly provided on the lower surface of the support member 21 a which is laid across the width direction under the transport unit frame 21. It makes contact and urges the carrying part frame 21 in the lifting direction.

When the carrier frame 21 is moved and displaced relative to the photosensitive drum 11 from the operating position to a retracted position (see FIG. 13) distant from the operating position by a predetermined distance downward, and then returned from the retracted position to the operating position, Positioning means 29 is provided between the photosensitive drum and the inner surface of the machine body frame 24 in order to correctly correspond to the specified position for setting the transport unit frame 21. This positioning means 2
The positioning pins 29a are provided on the outer surfaces of the left and right plates of the carrier frame 21 and the positioning blocks 29b are attached to the inner surfaces of the machine body frame 24. The positioning block 29b is defined by the positioning pin 29a on the side of the carrier frame 21 contacting the lower surface of the positioning block 29b.
It should be noted that the positioning pin 29a and the positioning block 29b may be provided in the reverse order to the above.

An operating handle mechanism 40 is provided on the operating side of the machine body for swinging and displacing the carrying section frame 21. As shown in FIGS. 6 to 8, the operation handle mechanism 40 has a base end portion having a fulcrum shaft 26 of the support link mechanism 25.
A lever 41 of a required length fixed to the end of the lever, a handle 42 pivotally supported by a tip end of the lever 41, and a lockable state at the operating position by the support link mechanism 25. The unlocking part 51 of the unlocking means 50 is provided. The unlocking means 50
The fixed side of the operation handle mechanism 4 is attached to the body frame 24.
It is provided facing 0.

As described above, the lever 41 of the operating handle mechanism 40 has its base end 41 'fixed to one end of the fulcrum shaft 26 outside the machine frame 24, and its longitudinal axis is, for example, that of the support link mechanism 25. It is arranged so as to be parallel to the longitudinal axis of the lower link 25b. A supporting piece 43 is fixed to the tip of the lever 41, and a connecting plate 44 formed of a metal plate in a downward U shape is pivotally attached to the upper end of the supporting plate 43 by a connecting pin 45. A handle 42 is attached at its tip.

Inside the connecting fitting 44, a releasing piece 51 which constitutes the unlocking means 50 is supported by the connecting fitting 44 by a shaft pin 52 so that the tip end thereof is projected forward and is rotated in the vertical direction. The handle 42 is movably provided.
Along with it, it is adapted to be rotated in the vertical direction. The releasing piece 51 can be rotated only downward by a torsion coil spring 53 that engages with the shaft pin 52 and the tip of the connecting fitting 44, and is always downward by the tip of the plate piece forming the connecting fitting 44. It is held so as to abut the bent locking portion 44 '.

A fixed side of the unlocking means 50 with respect to the above-mentioned operation handle mechanism 40 is a cam 55 having an inclined surface 55 'fixed to the outer surface of the machine body frame 24. The cam 55 is fixed to a base plate 56, and is attached to the machine body frame 24 so as to face the release part 51 attached to the tip of the handle 42 by the base plate 56. The positional relationship between the cam 55 and the operation handle mechanism 40 is shown in FIG. That is, the operation handle mechanism 4
0 is a state in which the handle 42 is rotated downward on the connecting pin 45 to be folded along the lever 41 as shown in FIGS. 8 and 9 when the transport unit frame 21 is in the operating position, The release piece 51 attached to the tip of the handle 42 does not come into contact with the cam 55,
It is located in a forward position and is in an upward position.

In the support mechanism of the paper transporting unit of the present embodiment thus configured, the transport unit 20 is in the operating position (see FIG. 4).
(See), the support link mechanism 25 receives the side surface of the lower link 25b by the stopper 27 so that the position of the intermediate connecting pin 25d between the upper link 25a and the lower link 25b is located on the right side of the figure from the dead point line b. Therefore, the transport unit frame 21 is placed at this operating position.
Is kept and locked. At this point in time, the operation handle mechanism 40 is in the state shown in FIG. 9, and as shown in FIG. 10, the unlocking piece 51 attached to the operation handle mechanism 40 is positioned upward, so that the transport section is The frame 21 is never displaced.

In order to move and displace the transport unit 20 from the operating position to the retracted position (see FIG. 13), first, as shown in FIG. 11, the handle 42 of the operating handle mechanism 40 is moved.
After grasping and pulling up in the direction of arrow c, the handle 42 can be rotated in the direction of arrow d while still being grasped. During this operation, when the handle 42 is grasped and pulled up to the front, the handle 42 will move to the lever 4
The release piece 51, which is rotated on the connecting pin 45 with 1 and is supported by the connecting fitting 44 at the tip, is also rotated at the same time. Then, the release portion piece 51 moves downward and is engaged with the inclined surface 55 ′ of the cam 55 on the machine body frame 24 side located at the opposite position. At this time, when the releasing piece 51 rotates in the direction of the arrow c ′ as shown in FIG.
5 is first contacted with the upper part of the inclined surface 55 ', and thereafter as the rotational displacement proceeds, the inclined surface 5'
It is guided to 5'and forced to move to the lower left. As a result, when the handle 42 is in a substantially horizontal state, the lever 41 is pivotally displaced from the position shown in FIG. 8 to the position shown in FIG. 16 almost instantly. During this period, the fulcrum shaft 26 to which the base end portion 41 'of the lever 41 is connected and fixed
It is possible to overcome the pushing force of the fulcrum support spring 28 and push it down for a moment to move the intermediate connecting pin 25d between the upper link 25a and the lower link 25b beyond the dead point line b to the left side in the figure.

Therefore, the carrier unit 20 can be displaced to the retracted position by the rotation of the lever 41 of the operator who operates the handle 42 by its own weight. Since the lifting force by the torsion coil spring 34 of the push-up means 30 is constantly urged to the lower side of the transporting unit frame 21 during this movement, it can be moved without dropping suddenly. When the transport unit 20 is moved to the retracted position, the above-mentioned support link mechanism 2 as shown in FIG.
5 and the pushing-up means 30 are both in a folded state, and the posture in the retracted position is maintained by the load acting on the transport unit 20.

In order to return the transport unit 20 to the operating position after the cleaning around the photosensitive drum 11 and the jam processing are completed, the operation handle mechanism 40 can be operated in the opposite direction. The operation of returning the transport unit 20 to the operating position will be described below.

In order to return the transport unit 20 to the operating position, the handle 42 of the operating handle mechanism 40 is held and rotated in the right direction in FIG. 11 contrary to the above operation. Then, the lever 41 of the operation handle mechanism 40 causes the upper link 25a via the fulcrum shaft 26 of the support link mechanism 25.
The lower link 25b is rotationally displaced from the state shown in FIG. 15 (a) in the direction of the arrow e with the fulcrum shaft 26 as a reference, and the upper and lower links 25a, 25b are erected. When the support link mechanism 25 is erected, the carrier frame 21 connected by the upper link 25a and the connecting pin 25c is rotated toward the operating position with the support shaft 22 as a base point. Eventually, when the upper and lower links 25a and 25b of the support link mechanism 25 are displaced to the state shown in FIG. 15 (b), the positioning pins 29a attached to the transport unit frame 21 will move the positioning pins 29a.
The positioning block 29b on the fourth side is contacted, and the conveyance frame 21 is prevented from rising further. That is, the contact between the positioning block 29b and the positioning pin 29a means that the transport unit 20 has reached the specified position shown in FIG. 14 with respect to the photosensitive drum 11. During this time, the roller 36 is urged by the torsion coil spring 34 of the pushing-up means 30 while the roller 36 rolls along the lower surface of the support member 21a. Therefore, the handle 42 can be lightly operated and lifted without applying a large force.

However, in this state, the support link mechanism 25
It is on the front side of the dead point line b as shown in FIG. Therefore, if the lifting operation by the operation handle mechanism 40 is interrupted, the transport unit 20 is in an unstable state. Therefore, by moving the handle 42 further to the right, the connecting portion between the upper and lower links 25a and 25b crosses the dead point line b and the lower link 25b is moved to the stopper 2 as shown in FIG. 15 (c).
The carrier unit 20 can be set in a state where the support link mechanism 25 can be stably supported by moving to a position where the carrier unit 7 is brought into contact, in other words, the operating position (see FIG. 4). After the transport unit frame 21 reaches the specified position, it remains at that position, and only the support link mechanism 25 is displaced. When the support link mechanism 25 is moved to the lock position, the fulcrum shaft 26 is momentarily pushed down against the supporting force of the fulcrum support spring 28 and crosses the dead point line. It is possible to confirm that the person is given a so-called click feeling and that the transport unit 20 is locked in the operating position. When the operation handle mechanism 40 is returned to its original position, the release piece 51 of the lock release means 50 attached to the tip of the handle 42 passes under the cam 55 on the machine frame 24 side. The cam 55 does not collide with the release piece 51.

Once the transport unit 20 has been set to the operating position in this way, a malfunction can be prevented by folding the handle 42 of the operation handle mechanism 40.
When the handle 42 is rotated downward on the connecting pin 45 so as to be fitted to the lever 41 from the horizontal state, the release portion 51 attached to the tip of the handle 42 is rotated upward according to the rotation of the handle 42. At this time, if the cam 55 is brought into contact with the cam 55, the cam 55 can move backward and escape upward to return to the original position. The mode of displacement of this release piece 51 is shown in FIG.
Represents the state of displacement from right to left. The releasing piece 51 is attached to the connecting fitting 44 at the tip of the handle 42 so as to be rotatable only in the downward direction by the shaft pin 52 with the torsion coil spring 53 interposed, and therefore the handle 42 (not shown in this figure). Is moved to the storage position (the operation position of the transport unit 20) in a horizontal state, the release portion 51 is also horizontally positioned below the cam 55 (see (i) in the figure). Shown). When the lever (not shown) reaches the storage position, the release piece 51 is moved near the lower surface of the cam 55 by the pushing force of the fulcrum shaft support spring ((i in the figure).
i)). When the handle 42 is lowered downward, the release piece 5
1 is displaced upward and contacts the lower surface of the cam 55 (in the figure)
(iii)). When the handle 42 is further lowered, the release portion 51 is rotated downward by the cam 55 in inverse proportion to the rotation of the handle 42 according to the displacement of the handle 42 ((i
v)), and eventually, when the rotation angle of the handle 42 becomes large, the position of the shaft pin 45 of the release portion 51 with the shaft pin 45 connecting the lever 41 and the handle 42 as a fulcrum becomes high, and the shaft pin 52 The distance between the contact point of the release piece 51 and the contact point of the release piece 51 which is in contact with the surface of the cam 55 gradually increases, and eventually the release piece 51 is urged by the urging force of the torsion coil spring 53.
Is flipped up to break the contact with the cam 55 ((v) in the figure). As a result, the release part 51 is displaced upward from the position indicated by the chain line f as shown in FIG. 17 (vi), and the handle 42 is folded into the state shown in FIG.

When the handle 42 of the operation handle mechanism 40 is folded along with the lever 41 in this way, the support link mechanism 25 supporting the transport section frame 21 in this state is dead as described above. Since it is kept at a position beyond the point line b and cannot be pulled back as it is, it is kept at the operating position and kept in a locked state, and does not come off from the specified position during the operation of the image forming apparatus.

As described above, in the support mechanism of the sheet conveying portion of the present invention, the torsion coil spring 34 is used as the pushing-up means 30 with respect to the operating position of the conveying portion unit 20, and the movable end portion of the supporting mechanism is the supporting shaft of the conveying portion frame 21. By arranging it toward the 22 side, it is possible to move the transport unit 20 between the operating position and the retracted position with a small operating force. By the way, in comparison with the case where the direction of the torsion coil spring is provided in the opposite direction to the present embodiment, in the case of the present embodiment, the handle when the transport frame 21 is moved by the operation handle mechanism 40. The torque applied to 42 is generally average, and when the direction of the torsion coil spring 34 is reversed as described above, the torque applied to the handle 42 gradually increases, and becomes smaller when approaching the final position. It was not preferable because it caused a change in the human body.

The transport unit 2 in this embodiment
0 indicates the photosensitive drum 11 in the transport unit (1) of the present invention.
Is the photosensitive drum (2), the pushing-up means 30 is the urging means (3), and the support link mechanism 25 is the support link mechanism (4).
The operation handle mechanism 40 has an operation handle mechanism (5).
The unlocking means 50 corresponds to the unlocking means (6).

[0041]

According to the present invention configured as described above, the transport unit unit in which the image transfer unit for a sheet in the image forming apparatus and the transport units of the sheet before and after the unit are mounted and supported in series is retracted from the operating position. It can be moved up and down with respect to the position with a small operation force, and when the link mechanism at the support part crosses the dead point line, a click feeling is given to ensure the operation and hold. You can be sure. Also, when operating the transport unit from the operating position to the retracted position, the operation to lift the handle at the operating unit can simultaneously perform the operation to cross the deadline of the support link mechanism, so that the operation can be easily performed by so-called one-touch operation. it can.

[Brief description of drawings]

FIG. 1 is a principle configurational diagram of a first invention of a support mechanism of a sheet conveying unit of the invention.

FIG. 2 is a principle configurational diagram of a second invention of the support mechanism of the paper transport unit of the invention.

FIG. 3 is a schematic configuration diagram of a main part of an image forming apparatus to which a support mechanism for a sheet conveying unit according to an exemplary embodiment of the present invention is applied.

FIG. 4 is a vertical cross-sectional view showing a support mechanism of a paper transport unit according to the present embodiment.

5A and 5B are views showing a pushing-up means, FIG. 5A is a plan view, and FIG. 5B is a view showing end faces.

FIG. 6 is a diagram showing a relationship between a support link mechanism, a body portion, and an operation handle mechanism.

FIG. 7 is an enlarged vertical sectional view showing an operation handle mechanism of the support link mechanism.

FIG. 8 is a partially cutaway plan view of an essential part of the operation handle mechanism.

FIG. 9 is a front view of an operation handle mechanism.

FIG. 10 is a vertical cross-sectional view in which the handle of the operation handle mechanism is folded.

FIG. 11 is an explanatory view of using the operation handle mechanism.

FIG. 12 is an explanatory view of an operation mode of a lock releasing means of the support link mechanism.

FIG. 13 is a diagram illustrating an aspect when the sheet transport unit according to the present exemplary embodiment is moved to the retracted position.

FIG. 14 is a diagram showing an aspect at the time when the carrying unit is positioned during the ascending process.

FIG. 15 is an operation explanatory view of the support link mechanism.

FIG. 16 is an operation explanatory view of the operation handle mechanism.

FIG. 17 is an explanatory diagram of an operation of returning the lock releasing piece.

[Explanation of symbols]

 1, 20 Conveyor Unit Unit 2, 11 Photosensitive Drum 3, Biasing Means 4, 25 Support Link Mechanism 5, 40 Operation Handle Mechanism 6, 50 Lock Release Means 21 Conveyor Frame 22 Support Shaft 24 Machine Frame 25a Top Link 25b Bottom Link 25d intermediate connecting pin 26 fulcrum shaft 27 stopper 28 fulcrum support spring 29 positioning means 29a positioning pin 29b positioning block 30 pushing up means 31 mounting plate 32 movable spring base 33 shaft 34 torsion coil spring 34c spring movable part 35 bracket 36 roller 40 operation handle mechanism 41 Lever 42 Handle 43 Support Piece 44 Connection Metal Fitting 45 Connection Pin 51 Release Part Piece 52 Axis Pin 53 Torsion Coil Spring 55 Cam 56 Board

Claims (11)

[Claims] 1. A sheet conveying unit (1) is provided so as to be capable of swinging displacement with respect to a photosensitive drum (2) between an operating position and a retracted position, and the sheet conveying unit for the photosensitive drum (2). A support link mechanism (4) for holding (1) in the operating position, and a biasing means (3) for biasing the transport unit (1) between the operating position and the retracted position. A support mechanism for a sheet conveying unit in an image forming apparatus. 2. The transport unit (1) includes a tractor unit for feeding a sheet, a transfer unit, and a suction feeder unit for holding and transporting a sheet, and a transport frame for arranging and supporting these units has a sheet feeding side end. The support mechanism for the sheet conveying unit in the image forming apparatus according to claim 1, wherein the supporting mechanism is pivotally supported by the machine body. 3. A torsion coil spring is used as the urging means (3) for urging the transfer unit (1), and a movable operation part by the torsion coil spring is provided on the pivot side of the transfer unit (1). The support mechanism for the sheet conveying unit in the image forming apparatus according to claim 1, wherein the support mechanism is movably abutted so as to face the sheet. 4. The torsion coil spring is provided with a supporting spring base as a movable operating part, and a roller contacting a supporting member of the transport unit (1) is attached to a tip end of the supporting spring base. The support mechanism for the sheet conveying unit in the image forming apparatus according to claim 3. 5. The transport unit (1) is connected to at least a pair of support link mechanisms (4) at a movable end thereof and swingably displaced with respect to the photosensitive drum (2) between an operating position and a retracted position. The support portion of the support link mechanism (4) on the machine body side so that the support link mechanism (4) is supported movably and is set to a prescribed position by the positioning means so that the intermediate coupling portion of the link mechanism is held at a position beyond the dead point line. The support mechanism for the sheet transporting unit in the image forming apparatus according to claim 1, wherein the support is movably attached. 6. A fulcrum support spring is brought into contact with the link support portion on the machine body side of the support link mechanism (4) on the side on which the reaction force is raised with respect to the link fulcrum shaft, so that the support link mechanism (4 6. The support mechanism for the sheet transporting unit in the image forming apparatus according to claim 5, wherein the intermediate connecting unit is movable only when it crosses the dead point line. 7. An operation handle mechanism (5) connected to a support link mechanism (4) for oscillating and displacing the paper transport unit (1) with respect to the photosensitive drum (2) between an operating position and a retracted position. ) Is provided on the outer side of the machine body, and the movable base part of the operation handle mechanism (5) and the machine body side facing the movable base part are connected to each other when the transport unit (1) is reset from the operating position to the retracted position. A support mechanism for a sheet conveying unit in an image forming apparatus, characterized in that lock release means (6) for releasing the locked state by the support link mechanism (4) is provided. 8. The operation handle mechanism (5) has a lever of a required length, the base end of which is fixed to the fulcrum shaft of the support link mechanism (4) outside the machine body, and a trunk at the tip of the lever. 8. A support mechanism for a sheet conveying unit in an image forming apparatus according to claim 7, further comprising a handle for pivotally supporting the unit and attaching the unit in a retractable manner, and a releasing unit piece of the lock releasing means (6). . 9. The lever of the operation handle mechanism (5) is fixed at its base end to a fulcrum shaft in a posture facing the lower link of the support link mechanism (4). Item 8. A support mechanism for a sheet conveyance unit in the image forming apparatus according to Item 7. 10. The operation handle mechanism (5) of the lock release means (6) in a state where the operation handle mechanism (5) is set to an operating position of the transport unit (1) by the support link mechanism (4). ) The lever and the handle are provided with a cam provided on the outer surface on the side of the machine body that faces the pivotally attached portion, and a release piece attached to the main portion of the handle so as to face the cam. 10. A support mechanism for a sheet conveying unit in an image forming apparatus according to claim 8, wherein the support mechanism is a sheet conveying unit. 11. The lock releasing means (6) pushes up a releasing force which acts on a fulcrum shaft of the support link mechanism (4) by engaging a releasing piece with an inclined surface of the cam by a raising operation of the handle. 11. The image forming apparatus according to claim 7, wherein the intermediate connecting portion is configured to be disengaged so that the intermediate connecting portion can be displaced from the operating position to the retracted position over the dead point line. Support mechanism of the paper transport section in.