JP6805677B2 - Opening and closing mechanism and image forming device - Google Patents

Description

The present invention relates to an opening / closing mechanism and an image forming apparatus.

From the paper transport path for transporting the paper to be fed to the image forming unit, the fixed guide plate provided along one surface of the paper transport path, and the fixed guide plate along the other surface of the paper transport path. A movable guide plate rotatably provided so as to be separated from each other, a drive roller provided on the fixed guide plate side, and a drive provided on the movable guide plate side and in a state where the movable guide plate can be rotated and displaced integrally. A driven roller that can be brought in and out of the roller, a door body that is rotatably provided facing the movable guide plate, and a movable guide plate that transports paper in conjunction with the opening and closing operation of this door body. A connecting member that connects the two so as to rotate and displace along the road and at a position separated from each other, and is integrally fixed with the movable guide plate when the door body is closed. There is known a paper feeding device including an urging member that urges the connecting member in a direction in which the driven roller is in contact with the drive roller in a state where the driven roller is connected to and the door body is closed. Patent Document 1).

A fixing lever that is rotatably supported by the device main body, an opening / closing member provided on the device main body so as to be openable / closable, and either the device main body or the opening / closing member via a support shaft to fix the opening / closing member in a closed state. A connecting portion that is provided on the device body or the opening / closing member on the opposite side to the side on which the fixing lever is supported, and the fixing lever is connected when the opening / closing member is closed. An elastic member that positions the rotation angle position of the fixing lever at one of two positions, a fixed position where the opening / closing member is fixed by connecting to the connected portion and a standby position where it can be connected to the connected portion. When the opening / closing member is closed from the state where the opening / closing member is separated from the main body of the device and the fixing lever is in the fixed position, the fixing lever is connected together with the support shaft by acting on the fixing lever. An opening / closing mechanism including a connecting means for moving the support shaft to a position where it can be connected to the lever and a support shaft urging means for urging the support shaft at a position corresponding to the standby position of the fixed lever is also known (Patent Document 2). ..

Japanese Unexamined Patent Publication No. 5-208737 Japanese Unexamined Patent Publication No. 2011-53281

An object of the present invention is to provide an opening / closing mechanism and an image forming apparatus capable of reducing an operating force when opening / closing an opening / closing door.

In order to solve the above problems, the opening / closing mechanism according to claim 1 is used.
An opening / closing door that is rotatably supported between a closed position that covers the opening of the device body and an open position that opens the opening.
A link member rotatably supported by a rotating shaft provided on the main body of the device,
A first guide surface that moves while contacting the link member when the opening / closing door moves to the closed position, and a first guide surface that moves while contacting the link member when the opening / closing door moves to the open position. A guide member having 2 guide surfaces and
A switching member for guiding the link member from the first guide surface to the second guide surface is provided.
It is characterized by that.

The invention according to claim 2 is the opening / closing mechanism according to claim 1.
The link member rotates about the rotation axis while receiving a rotation moment with an elastic member stretched on the tip side.
It is characterized by that.

The invention according to claim 3 is the opening / closing mechanism according to claim 1 or 2.
When the opening / closing door moves from the open position to the closed position, the link member is such that the tip end side on which the elastic member is stretched at at least the end portion of the first guide surface exceeds the top dead center. The direction of the rotational moment is reversed, and the guide member is pulled in the moving direction of the opening / closing door.
It is characterized by that.

The invention according to claim 4 is the opening / closing mechanism according to any one of claims 1 to 3.
The switching member comes into contact with the link member whose direction of the rotational moment is reversed at at least at the end of the first guide surface, and swings while receiving the rotational moment of the link member to cause the link member to swing. Guide to the guide surface of 2,
Characterized by

The invention according to claim 5 is the opening / closing mechanism according to any one of claims 1 to 4.
The second guide surface has a steeper inclination angle than the first guide portion in a direction intersecting the moving direction of the opening / closing door and the first guide portion having a gentle inclination angle along the moving direction of the opening / closing door. It is composed of a second guide portion, and when the opening / closing door moves from the closed position to the opening position, the link member rotates along the first guide portion and moves to the opening position of the opening / closing door. The tip side, which rotates along the second guide portion and is stretched with the elastic member, crosses the top dead point and the direction of the rotational moment is reversed.
It is characterized by that.

In order to solve the above problems, the image forming apparatus according to claim 6 is used.
An image forming part that forms an image on paper,
A paper transport unit that transports the paper toward the image forming unit,
The opening / closing mechanism according to any one of claims 1 to 5 is provided.
It is characterized by that.

According to the inventions of claims 1 and 6, it is possible to reduce the operating force for closing the opening / closing door and suppress an increase in the operating force for opening the opening / closing door.
According to the second aspect of the present invention, the rotation direction of the link member can be switched.
According to the third aspect of the present invention, the operating force for closing the opening / closing door can be reduced.
According to the invention of claim 4, the pulling force of the opening / closing door can be received from the link member.
According to the fifth aspect of the present invention, it is possible to suppress an increase in the operating force for opening the opening / closing door.

It is a vertical cross-sectional schematic diagram which shows the internal structure of an image forming apparatus. It is sectional drawing which shows the internal structure of the paper transport part and the paper transport. It is sectional drawing of the paper transport unit. (A) is a schematic diagram showing the positional relationship between the opening / closing door and the paper transport unit when the paper transport unit is opened, and (b) is a schematic diagram of the paper transport unit showing the movement of the paper transport unit by closing the opening / closing door. is there. (A) is a schematic diagram showing the configuration of the opening / closing mechanism, and (b) is a schematic diagram showing the opening / closing mechanism in a state where the opening / closing door is locked at the closed position. It is a schematic diagram explaining the pulling-in operation of the opening / closing door by the link member when the opening / closing door moves to a closed position. It is a schematic diagram explaining the return operation of the link member when the opening / closing door moves to an open position.

Next, the present invention will be described in more detail with reference to the drawings below with reference to embodiments and specific examples, but the present invention is not limited to these embodiments and specific examples.
In addition, in the explanation using the following drawings, it should be noted that the drawings are schematic and the ratio of each dimension is different from the actual one, which is necessary for the explanation for easy understanding. Illustrations other than the members are omitted as appropriate.
In order to facilitate understanding of the following description, in the drawings, the front-back direction is the X-axis direction, the left-right direction is the Y-axis direction, and the up-down direction is the Z-axis direction.

(1) Overall Configuration and Operation of Image Forming Device FIG. 1 is a schematic vertical cross-sectional view showing an internal configuration of the image forming apparatus 1 according to the present embodiment.
Hereinafter, the overall configuration and operation of the image forming apparatus 1 will be described with reference to the drawings.

The image forming apparatus 1 includes a control device 10, a paper feeding device 20, a photoconductor unit 30, a developing unit 40, a transfer unit 50, a paper transport unit 60, a fixing unit 70, and the like in a housing 100. .. On the upper surface (Z direction) of the image forming apparatus 1, an ejection tray portion T for ejecting and accommodating paper on which an image is recorded is formed. Further, on the side surface (-X direction) of the image forming apparatus 1, an opening / closing door 210 that opens the inside of the image forming apparatus 1 is rotatably supported when the paper P is removed or inspected when a paper jam occurs. Has been done.

The control device 10 includes an image forming device control unit 11 that controls the operation of the image forming device 1, a controller unit 12 that prepares image data in response to a print processing request, and an exposure control unit 13 that controls lighting of the exposure head LH. It has a power supply device 14 and the like. The power supply device 14 applies a high voltage to the charging roller 32, the developing roller 42, the primary transfer roller 52, the secondary transfer roller 62, etc., which will be described later, and includes an exposure head LH, a paper feeding device 20, a fixing unit 70, and the like. Power is supplied to each sensor and the like.

The controller unit 12 converts the print information input from an external information transmission device (for example, a personal computer or the like) into image information for forming a latent image, and outputs a drive signal to the exposure head LH at a preset timing. .. The exposure head LH of the present embodiment is composed of an LED head in which a plurality of light emitting elements (LEDs: Light Emitting Diodes) are linearly arranged along the main scanning direction.

A paper feeding device 20 is provided at the bottom of the image forming device 1. The paper feeding device 20 includes a paper loading plate 21, and a large number of sheets P as recording media are loaded on the upper surface of the paper loading plate 21. The paper P loaded on the paper loading plate 21 is pulled out forward (in the −X direction) one by one from the upper side by the paper drawer portion 22, and then the drive roller 25a and the driven roller 25b via the paper guide guide 23. It is conveyed to the nip portion of the resist roller pair 25 made of.

Each of the photoconductor units 30 is provided in parallel above the paper feeding device 20 (Z direction), and includes a photoconductor drum 31. A charging roller 32, an exposure head LH, a developing unit 40, a primary transfer roller 52, and a cleaning blade 33 are arranged around the photoconductor drum 31 along the rotation direction.

The developing unit 40 has a developing housing 41 in which a developing agent is housed. In the developing housing 41, a developing roller 42 arranged to face the photoconductor drum 31 and a pair of augers 44 that agitate and convey the developer to the developing roller 42 side diagonally downward on the back surface side of the developing roller 42. 45 is arranged. A layer regulating member 46 that regulates the layer thickness of the developer is arranged close to the developing roller 42.
Each of the developing units 40 is configured in substantially the same manner except for the developer housed in the developing housing 41, and each forms a yellow (Y), magenta (M), cyan (C), and black (K) toner image. To do.

The surface of the rotating photoconductor drum 31 is charged by the charging roller 32, and an electrostatic latent image is formed by the latent image forming light emitted from the exposure head LH. The electrostatic latent image formed on the photoconductor drum 31 is developed as a toner image by the developing roller 42.

The transfer unit 50 is an intermediate transfer belt 51 on which each color toner image formed on the photoconductor drum 31 of each photoconductor unit 30 is multiple-transferred, and an intermediate transfer belt 51 on which each color toner image formed on each photoconductor unit 30 is multiple-transferred. A primary transfer roller 52 that sequentially transfers (primary transfer) to 51 is provided. Further, the intermediate transfer belt cleaner 54 for removing the residual toner adhering to the intermediate transfer belt 51 is provided.

The paper transport unit 60 includes a driven roller 25b of a resist roller pair 25 that corrects the posture of the paper P fed out from the paper feeding device 20 and feeds the paper P to the secondary transfer unit TR at the timing of the secondary transfer. It is provided with a secondary transfer roller 62 that collectively transfers (secondary transfer) each color toner image superimposed and transferred on the intermediate transfer belt 51 to paper P which is a recording medium. Further, the paper P on which the transferred toner image is held is guided to the fixing nip portion N of the fixing unit 70 via the transport guide 65.

Each color toner image formed on the photoconductor drum 31 of each photoconductor unit 30 is formed on an intermediate transfer belt by a primary transfer roller 52 to which a predetermined transfer voltage is applied from a power supply device 14 or the like controlled by an image forming device control unit 11. Electrostatic transfer (primary transfer) is sequentially performed on the 51, and a superimposed toner image on which each color toner is superimposed is formed.

The superimposed toner image on the intermediate transfer belt 51 is conveyed to the secondary transfer unit TR as the intermediate transfer belt 51 moves. When the superimposed toner image is conveyed to the secondary transfer unit TR, the paper P is supplied to the secondary transfer unit TR from the resist roller pair 25 in accordance with the timing.
Then, a predetermined transfer voltage is applied to the secondary transfer roller 62 from the power supply device 14 or the like controlled by the image forming apparatus control unit 11, and the paper P sent out from the resist roller pair 25 is placed on the intermediate transfer belt 51. Multiple toner images are collectively transferred.

The residual toner on the surface of the photoconductor drum 31 is removed by the cleaning blade 33 and collected in a waste toner recovery container (not shown). The surface of the photoconductor drum 31 is recharged by the charging roller 32.

The fixing unit 70 has a heating module 71 and a pressure module 72, and a fixing nip portion N (fixing region) is formed by a pressure contact region between the heating module 71 and the pressure module 72. The paper P on which the toner image is transferred in the secondary transfer unit TR is conveyed to the fixing unit 70 via the transfer guide 65 in a state where the toner image is not fixed. The toner image of the paper P conveyed to the fixing unit 70 is fixed by the action of heating and crimping by the pair of heating modules 71 and the pressure module 72.

The paper P on which the fixing toner image is formed is discharged from the discharge roller pair 79 to the discharge tray portion T on the upper surface of the image forming apparatus 1 via the transport roller pair 78. Further, in the case of double-sided printing, when the rear end of the paper P whose surface is fixed passes through the transfer roller pair 78, the discharge roller pair 79 is reverse-driven and the reverse transfer is formed in the opening / closing door 210. From the road, the image is conveyed to the resist roller pair 25 and an image is formed on the back surface.

(2) Configuration and operation of the paper transport unit FIG. 2 is a schematic cross-sectional view showing the internal configuration and paper transport of the paper transport unit, FIG. 3 is a schematic cross-sectional view of the paper transport unit 60, and FIG. 4 (a) is a paper transport unit. FIG. 5 (a) is a schematic view showing the positional relationship between the opening / closing door 210 and the paper transport unit 60 when the door is opened, and FIG. 5 (a) is a schematic view of the paper transport unit showing the movement of the paper transport unit 60 by the closing operation of the opening / closing door 210. ) Is a schematic view showing the configuration of the opening / closing mechanism 200, and (b) is a schematic view showing the opening / closing mechanism 200 in a state where the opening / closing door 210 is locked at the closed position.
Hereinafter, the configuration and operation of the paper transport unit of the image forming apparatus 1 will be described with reference to the drawings.

The paper transport unit includes a housing 100, an opening / closing mechanism 200 including an opening / closing door 210, and a paper transport unit 60.

(2.1) Housing The housing 100 has an opening on the side (−X direction), and a photoconductor unit 30, a developing unit 40, a transfer unit 50, and the like are housed inside.
A bearing portion 101, which is the center of rotation of the opening / closing door 210, is formed at the lower end of the housing 100 on the opening side, and rotatably supports the rotating shaft 211 of the opening / closing door 210, which will be described later.

Lock pins 103 are provided on the upper portion of the housing 100 on the opening side so as to project in a direction intersecting the opening / closing direction of the opening / closing door 210.
Then, the recess 215a of the latch lever 215 rotatably provided above the opening / closing door 210 is fitted, and the opening / closing door 210 is fixed to the housing 100 with the opening closed.

(2.2) Opening / Closing Door The opening / closing door 210 rotates and supports the paper transport unit 60 inside, and the rotating shaft 211 is supported by the bearing portion 101 of the housing 100 to close the opening of the housing 100. Rotate between the position and the open position to open the opening.
On the inner surface of the opening / closing door 210 facing the housing 100, the outer side, which is one of the reversing transport paths through which the paper P whose transport direction is reversed after the surface is fixed, passes until it rejoins the resist roller pair 25. A transport guide 213 is formed.

The outer transport guide 213 holds a predetermined gap with the inner transport guide 631 formed in the paper transport unit 60 to form an inverted transport path.
A plurality of transport roller pairs 120, 130, 140 are arranged in the reversing transport path, and drive-side transport rollers 120a, 130a, 140a constituting the transport roller pairs 120, 130, 140 are arranged in the outer transport guide 213. ing.

(2.3) Paper Transfer Unit The paper transfer unit 60 is composed of a cash register unit unit 610, a secondary transfer unit unit 620, and a double-sided unit unit 630.

The cash register unit unit 610 has a first paper guide guide 611, a driven roller 25b of a resist roller pair 25, and a second paper guide guide 612. The drive roller 25a of the resist roller pair 25 is arranged on the apparatus main body side.
The first paper guide guide 611 guides the paper P fed from the paper feed device 20 and the paper P conveyed via the double-sided unit unit 630 to the nip portion of the resist roller pair 25. The second paper guide guide 612 guides the paper P, which is sent out from the resist roller pair 25 after correcting the posture, to the secondary transfer unit TR.

The secondary transfer unit unit 620 has a secondary transfer roller 62 and a transfer guide 65, and the secondary transfer roller is urged toward the intermediate transfer belt 51 on the paper P fed at the timing of the secondary transfer. The toner image held on the intermediate transfer belt 51 at 62 is collectively transferred (secondary transfer). The paper P on which the toner image is transferred is guided to the fixing nip portion N of the fixing unit 70 via the transfer guide 65.

The double-sided unit portion 630 has an inner transport guide 631 forming the other side of the reversing transport path facing the outer transport guide 213 formed on the inner surface side of the opening / closing door 210, and prints on both sides of the paper P. Transfer to the resist roller pair 25.
A pinch roller 130b of a transfer roller pair 130 and a pinch roller 140b of a transfer roller pair 140 are rotatably arranged on the inner transfer guide 631.

Further, on the lower side of the inner transport guide 631, a pair of left and right rotating shaft portions 632 are formed. The rotating shaft portion 632 is fitted and inserted into the bearing portion 212 formed on the side plates 210a on both sides of the opening / closing door 210, and the paper transport unit 60 is rotatably supported by the opening / closing door 210.

As shown in FIG. 4, one end of the compression coil spring S is fixed to both sides of the inner transfer guide 631, and the other end is fixed to the inner surface side of the opening / closing door 210 facing the inner transfer guide 631. As a result, when the opening / closing door 210 is fixed at the closed position, the urging force of the compression coil spring S acts on each other between the paper transport unit 60 and the opening / closing door 210.

Therefore, when the opening / closing door 210 moves to the open position, the paper transport unit 60 rotates with the movement of the opening / closing door 210, the nip of the resist roller pair 25 is released, and the secondary in the secondary transfer unit TR. The nip between the transfer roller 62 and the intermediate transfer belt 51 is also released.
Then, the inner transport guide 631 and the outer transport guide 113 forming the reversal transport path are opened to each other by the urging force of the compression coil spring S, and the nips of the transport rollers pairs 120, 130, and 140 are also released.

When returning the opening / closing door 210 from the open position to the closed position, the opening / closing door 210 is rotationally moved toward the housing 100.
As the opening / closing door 210 rotates toward the housing 100, the paper transport unit 60 also rotates toward the housing 100, and the nip of the resist roller pair 25 and the nip of the secondary transfer roller 62 in the secondary transfer unit TR. The recess 215a of the latch lever 215 is fitted into the lock pin 103 and fixed in a state of receiving the reaction force due to the above.

(2.4) Opening / Closing Mechanism The opening / closing mechanism 200 applies a rotational moment M to the opening / closing door 210, the guide member 220 arranged in the opening / closing door 210, the switching member 230, the link member 240 arranged in the housing 100, and the link member 240. It is composed of a tension coil spring 250 as an example of the elastic member to be applied.

The guide member 220 is fixedly arranged above the opening / closing door 210 and below the latch lever 215. As shown in FIG. 5A, the guide member 220 opens the first guide surface 221 that moves while contacting the link member 240 described later when the opening / closing door 210 moves to the closed position, and the opening / closing door 210. It has a second guide surface 222 that moves while contacting the link member 240 when moving to the position.

The first guide surface 221 forms a movement locus diagonally downward from the start end 221a that receives the stud 242 of the link member 240 to the end end 221b when the opening / closing door 210 moves to the closed position.

The second guide surface 222 is formed below the first guide surface 221 and intersects the moving direction of the opening / closing door 210 with the first guide portion 222A having a gentle inclination angle along the moving direction of the opening / closing door 210. It is composed of a second guide portion 222B having a steeper inclination angle than the first guide portion 222A in the direction, and forms a movement locus that moves while contacting the stud 242 of the link member 240 when the opening / closing door 210 moves to the open position. ing.

The switching member 230 has arm portions 232 protruding on both sides of the rotating shaft 231 and is rotatably provided below the end 221b of the first guide surface 221 and above the start end 222a of the second guide surface 222. ing.
In the switching member 230, when the stud 242 of the link member 240 in which the first guide surface 221 moves and rotates crosses the top dead center at the end 221b of the first guide surface 221, one arm portion 232 links. It is designed to receive the inverted rotational moment M of the member 240. As a result, a pulling force toward the housing 100 side acts on the opening / closing door 210, and the operating force of the opening / closing door 210 to the closed position is reduced.

A stopper 225 is formed below the rotation shaft 231 of the switching member 230, and contacts the arm portion 232 of the switching member 230 to regulate the rotation of the switching member 230.

The link member 240 is rotatably supported by the housing 100 with a rotation shaft 104 at the base end side 240a. The tip side 240b has a stud 242 protruding in a direction intersecting the rotation direction, and a tension coil spring 250 is stretched on the stud 242. As a result, the link member 240 is clockwise or counterclockwise with the position where the tension direction of the tension coil spring 250 and the virtual line c1 connecting the rotating shaft 104 and the stud 242 overlap on the same straight line as the top dead point. The rotational moment M due to the tension coil spring 250 acts by reversing to either one (see the middle arrow M in FIGS. 5A and 5B).

(3) Opening / Closing Operation of Opening / Closing Door FIG. 6 is a schematic view illustrating an operation of pulling in the opening / closing door 210 by the link member 240 when the opening / closing door 210 moves to the closed position, and FIG. 7 shows the opening / closing door 210 moving to the open position. It is a schematic diagram explaining the return operation of the link member 240 at the time. Hereinafter, the operation of the opening / closing mechanism 200 will be described with reference to the drawings.

When returning the opening / closing door 210 from the open position to the closed position, the user rotates the opening / closing door 210 toward the housing 100.
Along with the rotational movement of the opening / closing door 210 toward the housing 100, the guide member 220 fixed to the opening / closing door 210 also rotates and moves toward the housing 100, and the studs 242 of the link member 240 arranged in the housing 100 Contact is made from the start end 221a side of the first guide surface 221 (see FIG. 6A).
Then, when the opening / closing door 210 is further rotated and moved to the closed position, the stud 242 of the link member 240 rotates along the movement locus of the first guide surface 221 and reaches the top dead center at the end 221b of the first guide surface 221. It is positioned and the rotational moment M does not act (see FIG. 6B).

Then, the link member 240 whose stud 242 has reached the top dead center contacts the arm portion 232 of the switching member 230 at the same time as the direction of the rotational moment M is reversed to rotate the switching member 230.
The switching member 230 receives the rotation moment M of the link member 240 in which the direction of the rotation moment M is reversed while the rotation is restricted by the stopper 225, and the opening / closing door 210 receives the rotation moment M of the link member 240 in the closing position direction. (See FIG. 6 (c)).
As a result, the reaction force due to the nip of the resist roller pair 25 and the nip of the secondary transfer roller 62 can be partially offset to reduce the operating force.

Further, when the opening / closing door 210 is rotationally moved to the closed position, the stud 242 of the link member 240 passes through the arm portion 232 of the switching member 230, the switching member 230 returns to the standby position, and the link member 240 returns to the closed position. To reach. Then, the recess 215a of the latch lever 215 is fitted into the lock pin 103 provided in the housing 100, and the opening / closing door 210 is fixed at the closed position (see FIG. 5B).

When moving the opening / closing door 210 from the closed position to the open position, the user pulls up the latch lever 215 provided above the opening / closing door 210 to release the engagement with the lock pin 103 provided in the housing 100. The opening / closing door 210 is rotationally moved toward the side of the image forming apparatus 1 main body (in the −X direction in FIG. 1).

When the rotational movement of the opening / closing door 210 is started, the stud 242 of the link member 240 rotates along the first guide portion 222A of the second guide surface 222 of the guide member 220. Since the first guide portion 222A of the second guide surface 222 has a gentle inclination angle along the moving direction of the opening / closing door 210, it is in the same direction as the acting direction of the pulling force F due to the rotational moment M (FIG. 7 (a)), the increase in the operating force of the opening operation of the opening / closing door 210 is suppressed.

When the opening / closing door 210 is further rotated, the stud 242 of the link member 240 rotates along the second guide portion 222B having a steeper inclination angle than the first guide portion 222A and rotates when the top dead center is reached. The moment M does not act (see FIG. 7B).
Then, as the opening / closing door 210 rotates, the direction of the rotational moment M reverses and the link member 240 returns to the standby position for accepting the rotational movement of the opening / closing door 210 to the closed position (see FIG. 7C).

In this way, when the opening / closing door 210 is returned from the opened open position to the closed position, the link member 240 arranged in the housing 100 is first rotated along the first guide surface 221 of the guide member 220. The direction of the rotational moment M is reversed at the end 221b of the guide surface 221 of the above, and the pulling force F by the link member 240 acts on the opening / closing door 210 to reduce the operating force.

On the other hand, when the opening / closing door 210 is moved from the closed position to the open position, the link member 240 that assists the closing operation of the opening / closing door 210 has a gentle inclination angle of the second guide surface 222 that is different from that at the time of the closing operation. By rotating along the first guide portion 222A having the door, an increase in the operating force at the time of opening operation is suppressed.

1 ... Image forming device 10 ... Control device 20 ... Paper feeding device 25 ... Resist roller pair 30 ... Photoreceptor unit 40 ... Development unit 50 ... Transfer unit 60 ... Paper transport unit 610 ... Registration unit section 611 ... First paper guide guide 612 ... Second paper guide guide 620 ... Secondary transfer unit section 630 ... Double-sided unit section 631 ... Inner transport Guide 62 ... Secondary transfer roller 70 ... Fixing unit 100 ... Housing 103 ... Lock pin 104 ... Rotating shaft 210 ... Opening and closing door 213 ... Outer transport guide 215 ... Latch lever 220 ... Guide member 221 ... First guide surface 222 ... Second guide surface 225 ... Stopper 230 ... Switching member 240 ... Link member 242 ... Stud 250 ...・ ・ Tension coil spring (link member 240)
S ... Compression coil spring (paper transport unit 60)

Claims (6)

An opening / closing door that is rotatably supported between a closed position that covers the opening of the device body and an open position that opens the opening.
A link member rotatably supported by a rotating shaft provided on the main body of the device,
A first guide surface that moves while contacting the link member when the opening / closing door moves to the closed position, and a first guide surface that moves while contacting the link member when the opening / closing door moves to the open position. A guide member having 2 guide surfaces and
A switching member for guiding the link member from the first guide surface to the second guide surface is provided.
An opening and closing mechanism characterized by this. The link member rotates about the rotation axis while receiving a rotation moment with an elastic member stretched on the tip side.
The opening / closing mechanism according to claim 1. When the opening / closing door moves from the open position to the closed position, the link member is such that the tip end side on which the elastic member is stretched at at least the end portion of the first guide surface exceeds the top dead center. The direction of the rotational moment is reversed, and the guide member is pulled in the moving direction of the opening / closing door.
The opening / closing mechanism according to claim 1 or 2. The switching member comes into contact with the link member whose direction of the rotational moment is reversed at at least at the end of the first guide surface, and swings while receiving the rotational moment of the link member to cause the link member to swing. Guide to the guide surface of 2,
The opening / closing mechanism according to any one of claims 1 to 3, wherein the opening / closing mechanism is characterized in that. The second guide surface has a steeper inclination angle than the first guide portion in a direction intersecting the moving direction of the opening / closing door and the first guide portion having a gentle inclination angle along the moving direction of the opening / closing door. It is composed of a second guide portion, and when the opening / closing door moves from the closed position to the opening position, the link member rotates along the first guide portion and moves to the opening position of the opening / closing door. The tip side, which rotates along the second guide portion and is stretched with the elastic member, crosses the top dead point and the direction of the rotational moment is reversed.
The opening / closing mechanism according to any one of claims 1 to 4, wherein the opening / closing mechanism is characterized in that. An image forming part that forms an image on paper,
A paper transport unit that transports the paper toward the image forming unit,
The opening / closing mechanism according to any one of claims 1 to 5 is provided.
An image forming apparatus characterized in that.

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