JP2021043353A - Position holding mechanism and image forming apparatus - Google Patents

Abstract

To prevent falling from a holding position.SOLUTION: A position holding mechanism comprises: a connection member 10 that is provided on any one of an outer door and an inner door and includes a slide hole 12; and a connection boss 4 that is provided on the other of the outer door and the inner door and is connected to the slide hole 12 to slide the slide hole 12 in association with rotation of the inner door with respect to the outer door. The slide hole 12 has, in communication with each other, a first wide part 12a, a second wide part 12c and a third wide part 12f in which the length in a width direction W orthogonal to a slide direction D2 in which the connection boss 4 slides is equal to or longer than the length d1 in the width direction W of the connection boss 4, a first narrow part 12b that is provided between the first wide part 12a and the second wide part 12c and is less than the length in the width direction W of the connection boss 4, and a second narrow part 12d that is provided between the second wide part 12c and the third wide part 12f and is less than the length in the width direction W of the connection boss 4.SELECTED DRAWING: Figure 6

Description

The present invention relates to a position holding mechanism and an image forming apparatus capable of holding a rotatably provided unit at a predetermined position.

Conventionally, in a configuration including one unit and another unit that moves with respect to this unit, various configurations have been proposed as a position holding mechanism that holds the position of the other moving unit at a predetermined position. There is. As the position holding mechanism, for example, it is slidable with respect to a second unit provided movable with respect to the first unit and a connecting boss provided with the first unit and provided with the second unit. There is known one provided with a connecting member connected to (see Patent Document 1). In the connecting member, the first hole portion whose length in the width direction orthogonal to the sliding direction is longer than the length in the width direction of the connecting boss and the second hole portion whose length in the width direction orthogonal to the sliding direction is shorter than the length in the width direction of the connecting boss are continuous. It has a slide hole that is formed as a target. In this position holding mechanism, the connecting boss of the second unit is loosely fitted into the first hole of the connecting member so that it is caught in the second hole and cannot be lowered, and the second unit is placed at a predetermined position. Can be held.

Japanese Unexamined Patent Publication No. 2016-133717

However, in the position holding mechanism described in Patent Document 1 described above, when the user vigorously moves the second unit to a predetermined position and suddenly opens the second unit, the second unit is connected by the weight and the impact of the operation. There is a risk that the boss will pass through the narrow second hole. In this case, when the connecting boss completely passes through the second hole, the second unit drops to the lowest position with respect to the first unit at once, and the first unit, the second unit, or the second unit, or There is a risk of damaging peripheral parts.

An object of the present invention is to provide a position holding mechanism and an image forming apparatus capable of suppressing a fall from a holding position.

The position holding mechanism according to one aspect of the present invention includes a first unit, a second unit rotatably provided with respect to the first unit, the first unit, and the second unit. A connecting portion provided on either one of the above and provided with a slide hole, and the second unit provided on any one of the first unit and the second unit, with respect to the first unit. It is provided with a connected portion connected to the slide hole so as to slide the slide hole as it rotates, and the slide hole is orthogonal to the sliding direction in which the connected portion slides. The first wide portion, the second wide portion, the third wide portion, and the first wide portion and the second wide portion whose length in the width direction is equal to or longer than the length in the width direction of the connected portion. The width of the connected portion provided between the first narrow portion, which is less than the length of the connected portion in the width direction, and the second wide portion and the third wide portion. It is characterized in that it has a second narrow portion that is less than the length in the direction in communication with the second narrow portion.

The image forming apparatus according to another aspect of the present invention includes a housing of the main body of the device, an image forming unit housed in the housing and forming a toner image on a sheet, and any one of claims 1 to 6. The first unit is an outer door that is rotatably provided in the housing and can open and close the housing by rotation, and the second unit is the second unit. It is an inner door rotatably provided inside the outer door, and when the inner door is rotated toward the outer door side and closed, a sheet is conveyed between the inner door and the outer door. The seat transport path is opened in a state where the path is formed and the inner door is rotated and opened to the side away from the outer door.

According to the present invention, it is possible to suppress a fall from the holding position.

The whole schematic which shows the image forming apparatus which concerns on embodiment. The side view which shows the state which the inner door is closed in the door unit of the image forming apparatus which concerns on embodiment. The side view which shows the state which the inner door is opened in the door unit of the image forming apparatus which concerns on embodiment. The perspective view seen from the lower side which shows the inner door of the image forming apparatus which concerns on embodiment. The perspective view which shows the 1st connection member of the image forming apparatus which concerns on embodiment. It is a front view which shows the 1st connecting member of the door unit of the image forming apparatus which concerns on embodiment, (a) is the figure for demonstrating the dimension in the width direction of each part, (b) is the sliding direction of each part. The figure for demonstrating the length of. It is a front view which shows the 1st connecting member of the door unit of the image forming apparatus which concerns on embodiment, (a) is a figure for demonstrating the position of a boss, (b) is explaining elastic deformation of the connecting member. Figure for. It is a front view which shows the 2nd connecting member of the door unit of the image forming apparatus which concerns on embodiment, (a) is the figure for demonstrating the dimension in the width direction of each part, (b) is the sliding direction of each part. The figure for demonstrating the length of.

<Configuration and outline of image forming apparatus>
The image forming apparatus 100 according to the embodiment of the present invention is an electrophotographic laser beam printer that forms a toner image of four colors. As shown in FIG. 1, the image forming apparatus 100 has a sheet feeding unit 110 for feeding the loaded sheets and an image forming unit 140 for forming a toner image to be transferred to the sheets. Further, the image forming apparatus 100 is provided with a fixing device 150 for fixing the image transferred to the sheet and a door unit that can be opened and closed with respect to the housing 101a (see FIG. 3) of the apparatus main body 101 of the image forming apparatus 100. (Position holding mechanism) 3 and.

When the image forming command is output to the image forming apparatus 100, the image forming process by the image forming unit 140 is started based on the image information input from an external computer or the like connected to the image forming apparatus 100. The image forming unit 140 includes an exposure device 142 and four process cartridges PY, PM, PC, and PK that form images of four colors of yellow, magenta, cyan, and black. The four process cartridges PY, PM, PC, and PK have the same configuration except that the colors of the images to be formed are different. Here, only the image formation process of the process cartridge PY will be described, and the process cartridges PM, PC, and PK will be described. The description of PK will be omitted.

The exposure apparatus 142 irradiates the photosensitive drum 141 of the process cartridge PY with the laser beam based on the input image information. At this time, the photosensitive drum 141 is precharged by a charging roller (not shown), and an electrostatic latent image is formed on the photosensitive drum 141 by being irradiated with laser light. After that, the electrostatic latent image is developed by the developer 143, and a yellow toner image is formed on the photosensitive drum 141.

Similarly, magenta, cyan, and black toner images are formed on the photosensitive drums of the process cartridges PM, PC, and PK. The toner images of each color formed on each photosensitive drum are transferred to the intermediate transfer belt 145 driven in the direction of arrow A by the primary transfer rollers 144Y, 144M, 144C, 144K, and the secondary transfer unit 130 is transferred by the intermediate transfer belt 145. Will be transported to. The secondary transfer unit 130 is composed of nip of the secondary transfer inner roller 131 and the secondary transfer outer roller 132 facing each other, and the toner is applied to the sheet S by applying a predetermined pressing force and electrostatic load bias by the nip. The image can be transferred. The image forming process of each color is performed at the timing of superimposing on the upstream toner image primaryly transferred on the intermediate transfer belt 145.

In parallel with the image forming process described above, the sheets S housed in the cassette 2 of the sheet feeding section 110 are separated one by one by the feeding separation section (not shown) and conveyed toward the registration roller pair 120. Will be done. In the present embodiment, the cassette 2 having only one stage is provided, but a plurality of cassettes for loading sheets of different sizes are provided, and the sheets are supplied according to the sheet size selected from the plurality of cassettes. You may send it.

The sheet S is skewed by the registration roller pair 120, and is conveyed to the secondary transfer unit 130 via the transfer transfer path 129. A full-color toner image on the intermediate transfer belt 145 is transferred to the first surface (surface) of the sheet S transported at a predetermined transfer timing by the electrostatic load bias applied to the secondary transfer unit 130. .. The sheet S on which the toner image is transferred is heated and pressurized in the fixing device 150, and the toner is melt-fixed (fixed) to the sheet S. For the sheet S that has passed through the fixing device 150, the transport path through which the sheet S is conveyed is selected by the first switching member f1, the second switching member f2, and the third switching member f3.

The sheet S guided to the first discharge roller pair 160 by the first switching member f1 is discharged to the first discharge tray 170. The sheet S guided to the second discharge roller pair 161 by the first switching member f1 and the second switching member f2 is discharged to the second discharge tray 171. Further, the sheet S guided to the second discharge roller pair 161 is guided to the third discharge roller pair 162 by the third switching member f3 while the second discharge roller pair 161 is driven in the reverse direction, so that the third discharge tray is guided to the third discharge tray. It is discharged to 184.

Further, when an image is formed on both sides of the sheet S, the sheet S on which the image is formed on the first surface is guided to the double-sided path 164 by the third switching member f3, and the registration roller is guided by the double-sided roller pair 163 or the like. It is transported up to 120 pairs. Then, a toner image is formed on the second surface (back surface) of the sheet S by the secondary transfer unit 130. The sheet S in which the toner image is fixed to the sheet by the fixing device 150 and the images are formed on the first and second surfaces is selected from the first discharge tray 170, the second discharge tray 171 and the third discharge tray 184. Is discharged.

<Door unit>
Next, the door unit 3 will be described in detail. As shown in FIGS. 1 to 3, the door unit 3 is centered on an outer door 31 rotatably (openable and closable) with respect to the apparatus main body 101 and a shaft 32a. The inner door 32 is provided so as to be rotatable (openable / closable) with respect to the outer door 31. The outer shape of the door unit 3 is shown by the broken line in FIG. 1, and the transfer transfer path 129 (see FIG. 1) is opened by opening the outer door 31 in the R1 direction shown in FIG. 2, for example, the transfer transfer path. The sheet S jammed in 129 can be taken out.

<Outer door>
As shown in FIGS. 2 and 3, the outer door (first unit) 31 is rotatably provided in the housing 101a, and the housing 101a can be opened and closed by rotation. The outer door 31 is provided with bosses 5, 15 (see FIG. 4) extending back and forth in a direction orthogonal to the opening / closing direction of the outer door 31.

<Inner door>
The inner door (second unit) 32 is rotatably provided inside the outer door 31. As shown in FIG. 2, when the inner door 32 is rotated toward the outer door 31 side (outer door side, R1 direction) and closed, a double-sided pass (sheet) is provided between the inner door 32 and the outer door 31. Transport path) 164 (see FIG. 1) is formed. As shown in FIG. 3, when the inner door 32 is rotated and opened on the side away from the outer door 31 (in the R2 direction), the double-sided pass 164 is opened. As a result, it is possible to easily access the double-sided path 164, which is difficult to jam by simply opening the outer door 31.

As shown in FIG. 4, the inner door 32 is provided with connecting bosses (connected portions) 4, 14. In the present embodiment, the connection boss (first connected portion) 4 on the front side and the connecting boss (second connected portion) 14 on the back side are provided at two locations. These connecting bosses 4 and 14 are provided so as to be parallel to the bosses 5 and 15 of the outer door 31 in the axial direction. Further, as shown in FIG. 3, the connecting bosses 4 and 14 are provided on the rotation center side, that is, on the shaft 32a side of the center of gravity position G of the inner door 32 when viewed from the rotation axis direction of the inner door 32. As shown in FIG. 4, the front edge of the inner door 32, that is, the edge of the connecting boss 4 in the direction of the rotation axis, is provided with an operation unit 34 for the user to grip when opening and closing. When the user opens and closes the inner door 32, he / she grabs the operation unit 34 and operates the inner door 32 to rotate.

When the user grabs and lifts the operation unit 34, the inner door 32 may bend and deform due to its own weight. In the vicinity of the operation unit 34 at that time, the amount of deformation due to the bending of the connecting member 10 in the sliding direction, which will be described later, is defined as Y1 with respect to the front-rear direction D1 of the inner door 32. Further, on the axes of the front and rear connecting bosses 4 and 14 provided on the inner door 32, the amount of deformation due to the bending of the connecting member 10 in the sliding direction with respect to the front and rear direction D1 of the inner door 32 is defined as Y2. Since the operation unit 34 has a longer distance from the shaft 32a than the connecting boss 4, the relational expression of the deformation amount is Y1> Y2.

The inner door 32 forms one side portion 164a of the double-sided pass 164 by the surface on the outer door 31 side. Therefore, the one-side portion 164a is provided with a single-sided roller 163a or the like of a double-sided roller pair 163. Further, as shown in FIGS. 2 and 3, the inner door 32 has a first guide portion 33a and a second guide portion 33b forming a sheet transport path such as a transfer transfer path 129 on the side opposite to the outer door 31 side. have. The first guide portion 33a is provided to form one side portion of the upstream side transport path 165 (see FIG. 1) for carrying the sheet S into the fixing device 150 (see FIG. 1). The second guide portion 33b is provided to form one side portion of the downstream side transport path 166 (see FIG. 1) for carrying out the sheet S from the fixing device 150.

<Connecting member>
The door unit 3 includes a connecting member (connecting portion, first connecting portion) 10 engaged with the boss 5 of the outer door 31. As shown in FIG. 5, a convex portion 5a protruding in the radial direction is provided at the tip end portion of the boss 5 of the outer door 31. At the end of the connecting member 10, an engaging hole 11 having a notched recess 11a is formed. By assembling the connecting member 10 to the boss 5 and rotating the concave portion 11a and the convex portion 5a in phase with each other, the connecting member 10 is rotatably provided so as not to come off from the boss 5 in the rotation range of the inner door 32. Has been done. Further, as shown in FIG. 4, a connecting member (second connecting portion) 20 is rotatably provided on the boss 15 as well as the boss 5. In the present embodiment, the connecting members 10 and 20 installed on the bosses 5 and 15 all have the same shape.

The bosses 5 and 15 have the same shape except that the directions D1 in the front-rear direction are opposite, and the connecting bosses 4 and 14 have the same shape except that the directions D1 in the front-rear direction are opposite. .. Therefore, here, as the connecting members 10 and 20, the first connecting member 10 that connects the boss 5 and the connecting boss 4 will be described. However, the configuration and operation of the second connecting member 20 (see FIG. 8) that connects the boss 15 and the connecting boss 14 are the same.

As shown in FIGS. 6A and 6B, a slide hole (first slide hole) 12 is formed in the central portion of the connecting member 10 to slidably support the connecting boss 4 of the inner door 32. Has been done. The connecting member 10 is slidably and rotatably connected to the inner door 32 via the connecting boss 4 and the slide hole 12. That is, as the inner door 32 rotates with respect to the outer door 31, the connecting member 10 and the connecting boss 4 slide relative to each other so that the connecting boss 4 follows the longitudinal direction of the slide hole 12. .. The slide hole 12 is formed so as to extend in the longitudinal direction of the connecting member 10, and the connecting member 10 is formed of an elastic member such as resin.

The slide holes 12 have different hole shapes in the sliding direction D2 in which the connecting boss 4 slides and move, and are conveniently partitioned by the difference in the hole shapes. In the present embodiment, the slide hole 12 includes a first wide portion 12a, a first narrow portion 12b, a second wide portion 12c, a second narrow portion 12d, an inclined portion 12e, and a third wide portion 12f. And have them in communication. That is, the first narrow portion 12b is provided between the first wide portion 12a and the second wide portion 12c. Further, a second narrow portion 12d is provided between the second wide portion 12c and the third wide portion 12f. The third wide portion 12f is arranged on the engaging hole 11 side, and the first wide portion 12a is arranged on the tip portion on the opposite side of the engaging hole 11.

The structure and operation of the connecting member 20 that connects the boss 15 and the connecting boss 14 are the same, and as shown in FIG. 8A, the connecting member 20 has a slide hole (second slide hole) 22. .. Similar to the slide hole 12, the slide hole 22 has a first wide portion (fourth wide portion) 22a in which the length in the width direction W is equal to or greater than the length d1 in the width direction W of the connecting boss 14, and the second wide portion. It has a portion 22c and a third wide portion (fifth wide portion) 22f. Further, the slide hole 22 includes a first narrow portion (third narrow portion) 22b and a second narrow portion 22d, which are less than the length d1 in the width direction W of the connecting boss 14, similarly to the slide hole 12. ,have. The first narrow portion 22b is provided between the first wide portion 22a and the second wide portion 22c. Further, an inclined portion 22e is provided between the second narrow portion 22d and the third wide portion 22f. The third wide portion 22f is arranged on the engaging hole 21 side, and the first wide portion 22a is arranged on the tip portion on the opposite side of the engaging hole 21.

Next, the dimensional relationship between the slide hole 12 and the connecting boss 4 in the first connecting member 10 will be described. As shown in FIGS. 6A and 6B, the connecting boss 4 is formed in a cylindrical shape, and the length d1 in the width direction W orthogonal to the sliding direction D2 (longitudinal direction of the slide hole 12) is , Matches the length of the outer diameter. The lengths W1, W3, and W5 of the first wide portion 12a, the second wide portion 12c, and the third wide portion 12f of the slide hole 12 in the width direction W are set to the length d1 or more in the width direction of the connecting boss 4. (Formula 1).
W1 ≧ d1, W3 ≧ d1, W5 ≧ d1 ... (1)

A small protrusion 12p facing the inside of the slide hole 12 is provided in a part of the third wide portion 12f. The small protrusion 12p functions as a weak stopper when the connecting boss 4 is located at the closed position 4A (see FIG. 7A), and in the portion where the small protrusion 12p is provided, the width direction of the third wide portion 12f The length W5 in W is slightly smaller than the length d1. Further, the connecting member 10 has a recess 13 continuously formed in the first wide portion 12a. The recess 13 is continuously formed from the first wide portion 12a to the side opposite to the first narrow portion 12b, and the length in the width direction W is less than the length in the width direction W of the connecting boss 4. As will be described later, the recess 13 is provided so that the connecting member 10 can be easily elastically deformed in the width direction W.

Further, the lengths W2 and W4 of the first narrow portion 12b and the second narrow portion 12d of the slide hole 12 in the width direction W are set to be less than the length d1 in the width direction W of the connecting boss 4. Formula 2). Further, with respect to the width direction W, the length W4 of the second narrow portion 12d is set to be less than the length W2 of the first narrow portion 12b (Formula 2).
W2 <d1, W4 ≤ W2 <d1 ... (2)

Further, in the present embodiment, the inclined portion 12e is provided between the third wide portion 12f and the second narrow portion 12d. The inclined portion 12e gradually reduces the length of the width direction W from the third wide portion 12f toward the second narrow portion 12d, and the length d1 of the width direction W of the connecting boss 4 with respect to the sliding direction D2. It is provided longer.

Regarding the sliding direction D2, the length of the first wide portion 12a is L1, the length of the second wide portion 12c is L2, and the length of the third wide portion 12f is L3. The length L1 of the first wide portion 12a is set to be larger than the deformation amount Y2 of the connecting boss 4 (L1> Y2). The length L2 of the second wide portion 12c is set to be larger than the length d1 in the width direction of the connecting boss 4 (L2> d1). Further, the length L3 of the third wide portion 12f is set to be longer than the length L1 of the first wide portion 12a and the length L2 of the second wide portion 12c (L3> L1> L2).

Next, the action when the inner door 32 is opened and closed with respect to the outer door 31 will be described. As shown in FIG. 7A, the connecting boss 4 of the inner door 32 moves in the slide hole 12 according to the opening / closing operation of the inner door 32. Here, the position where the connecting boss 4 is located in the third wide portion 12f is set as the closing position 4A, and the position where the connecting boss 4 is located in the first wide portion 12a is set as the first opening position 4D. The position where the connecting boss 4 is located in the second wide portion 12c is defined as the second opening position 4C.

When the inner door 32 is closed by the outer door 31, the connecting boss 4 is located at a position close to the engaging hole 11 at the closing position 4A. Then, as the inner door 32 is gradually opened by the user, the connecting boss 4 is slid over the small protrusion 12p of the third wide portion 12f from a position close to the boss 5. The connecting boss 4 is guided from the end of the third wide portion 12f to the inclined portion 12e, and moves toward the holding start position 4B where the length in the width direction W is d1. The shape of the inclined portion 12e including the holding start position 4B is formed by a gentle slope. Therefore, when the inner door 32 is opened, the connecting boss 4 smoothly moves in the slide hole 12 without suddenly increasing the operating force at the holding start position 4B, and the connecting boss 4 is moved to the first wide portion. It can be moved toward 12a. By configuring the connecting member 10 so as to satisfy the above-mentioned formulas 1 and 2, the connecting boss 4 can slide and move in the slide hole 12 without generating a large sliding resistance. The operation force of the user can be reduced.

Next, when the connecting boss 4 is located in the section from the holding start position 4B to immediately before the second opening position 4C, the length W4 of the second narrow portion 12d in the width direction W is from the length d1 of the connecting boss 4. The connecting boss 4 presses the connecting member 10 outward because it is also short. The force acting on the connecting member 10 and the state of deformation at this time are shown in FIG. 7 (b). An external force F1 acts on the connecting member 10 from the connecting boss 4. Then, the connecting member 10 is slightly elastically deformed in the arrow T direction (outward with respect to the slide hole 12), and the connecting boss 4 moves in the second narrow portion 12d in a light press-fitting state. Since the recess 13 is provided, the connecting member 10 can be easily deformed. At this time, a predetermined sliding resistance acts on the connecting boss 4, but the sliding resistance is not large enough to hold the inner door 32 at a desired position.

Further, as shown in FIG. 7A, when the connecting boss 4 passes through the second narrow portion 12d, it enters the second wide portion 12c and is located at the second opening position 4C. At this time, since the length W3 of the second wide portion 12c in the width direction W is equal to or greater than the length d1 of the connecting boss 4, the connecting boss 4 does not press the connecting member 10 outward, and the sliding resistance is increased. Does not occur. Then, when the connecting boss 4 slides from the second opening position 4C toward the first opening position 4D, the length W2 of the first narrow portion 12b in the width direction W becomes larger than the length d1 of the connecting boss 4. Due to its short length, the connecting boss 4 presses the connecting member 10 outward. As shown in FIG. 7B, an external force F2 acts on the connecting member 10 from the connecting boss 4. Then, the connecting member 10 is slightly elastically deformed in the direction of the arrow T, and the connecting boss 4 moves in the first narrow portion 12b in a light press-fitting state. Since the recess 13 is provided, the connecting member 10 can be easily deformed. At this time, a predetermined sliding resistance acts on the connecting boss 4, but the sliding resistance is not large enough to hold the inner door 32 at a desired position.

Then, when the inner door 32 is further opened by the user, the connecting boss 4 reaches the section from the first opening position 4D to the overstroke position 4E, and the elastic deformation of the connecting member 10 is eliminated by the above-mentioned mathematical formula 1. .. When the connecting boss 4 is located at the first opening position 4D, the inner door 32 is opened to the maximum opening degree. At this time, the movement of the connecting boss 4 in the closing position 4A direction is regulated by the first narrow portion 12b in which the elastic deformation is eliminated and the dimensional relationship of the above-mentioned equation 2 is restored. Therefore, the inner door 32 is held in the open state unless an external force equal to or higher than the predetermined sliding resistance in the first narrow portion 12b is applied.

Further, the length L1 of the first wide portion 12a in the sliding direction has a length of the deformation amount Y2 or more in the front-rear direction of the inner door 32 or more. Therefore, as shown in FIGS. 6A and 6B and FIGS. 8A and 8B, the connecting bosses 4 and 14 are attached to the first wide portions 12a and 22a of the connecting members 10 and 20 respectively. Can be accommodated. That is, in the initial state in which the inner door 32 is closed, the first connecting boss 4 is located at the third wide portion 12f, and the second connecting boss 14 is also located at the third wide portion 22f. From this initial state, the operation portion 34 of the inner door 32 is cantilevered, and the first connecting boss 4 is the end portion of the first wide portion 12a opposite to the first narrow portion 12b, which is the overstroke position 4E. The second connecting boss 14 enters the first wide portion 22a of the connecting member 20 when the position is set to. Further, by releasing the cantilever of the operation portion 34 of the inner door 32, the first connecting boss 4 is located at the first opening position 4D of the first wide portion 12a, and the second connecting boss 14 is also the second. 1 It is located at the first opening position (not shown) of the wide portion 22a. Therefore, even if the inner door 32 cantilever causes bending, the connecting bosses 4 and 14 can be positioned at the first wide portions 12a and 22a of the connecting members 10 and 20.

Here, when the user vigorously opens the inner door 32 and drops the inner door 32 when the connecting boss 4 is at the overstroke position 4E, each connecting boss 4 is caused by the impact of the drop. , 14 may pass through the first narrow portions 12b and 22b. However, according to the present embodiment, even if the connecting bosses 4, 14 pass through the first narrow portions 12b, 22b, they occur between the connecting bosses 4, 14 and the first narrow portions 12b, 22b. The falling speed of the inner door 32 can be reduced by the sliding resistance. As a result, the connecting bosses 4 and 14 are then stopped at the second narrow portions 12d and 22d, and can be held at the second opening positions 4C of the second wide portions 12c and 22c, so that the inner door 32 Can be prevented from falling to the closed position at once.

Further, if an external force is accidentally applied in the direction of closing the inner door 32 during the work in which the connecting bosses 4 and 14 are located at the first wide portions 12a and 22a, the connecting bosses 4 and 14 are respectively. There is a possibility that the first narrow portion 12b, 22b will be exceeded and the portion will fall. However, even in such a case, since the connecting bosses 4 and 14 are stopped by the second narrow portions 12d and 22d, it is possible to prevent the inner door 32 from falling to the closed state at once. In particular, in the present embodiment, the length W4 of the second narrow portion 12d is less than the length W2 of the first narrow portion 12b in the width direction W. Therefore, even if the door passes through the first narrow portion 12b, a larger sliding force is required to pass through the second narrow portion 12d, so that the careless drop of the inner door 32 can be further suppressed. Can be done.

On the other hand, when the inner door 32 is closed from the open state to the closed state, an external force equal to or greater than a predetermined sliding resistance in the first narrow portions 12b and 22b is applied by the user in the closing direction of the inner door 32 to connect the inner door 32. The bosses 4 and 14 move in a path opposite to the above-mentioned movement path. By being pushed down by an external force, the connecting bosses 4 and 14 are slid toward the second wide portions 12c and 22c against the sliding resistance in the first narrow portions 12b and 22b. The connecting bosses 4 and 14 are temporarily stopped by the second narrow portions 12d and 22d, but the external force that pushes them down further acts to resist the sliding resistance in the second narrow portions 12d and 22d. 3 It is slid toward the wide portions 12f and 22f. As a result, the inner door 32 can be closed.

As described above, in the present embodiment, the inner door 32 falls into the closed state as compared with the case where the narrow portion of the slide hole 12 for holding the inner door 32 in the open state is only one place. It is possible to further suppress this. Therefore, it is possible to prevent the inner door 32 from falling from the holding position with a simple configuration and low cost.

Further, in the present embodiment, the length L1 of the first wide portion 12a in the sliding direction is set to have a length of the deformation amount Y2 or more in the front-rear direction of the inner door 32. Therefore, the operation portion 34 of the inner door 32 is cantilevered, and the first connecting boss 4 is positioned at the overstroke position 4E, which is the end portion of the first wide portion 12a opposite to the first narrow portion 12b. When this is done, the second connecting boss 14 enters the first wide portion 22a of the connecting member 20. As a result, even if the inner door 32 cantilever causes bending, the connecting bosses 4 and 14 can be positioned at the first wide portions 12a and 22a of the connecting members 10 and 20. Therefore, it is possible to prevent the inner door 32 from falling from the holding position with a simple configuration and low cost.

Further, in the present embodiment, the connecting boss 4 is provided on the rotation center side, that is, on the shaft 32a side of the center of gravity position G of the inner door 32 when viewed from the rotation axis direction of the inner door 32. Therefore, the connecting member 10 can be shortened as compared with the case where the connecting member 10 is provided on the opposite side of the shaft 32a from the center of gravity position G. Therefore, it is possible to prevent the inner door 32 from falling from the holding position with a simple configuration and low cost.

In the above-described embodiment, the case where the connecting bosses 4 and 14 are provided on the inner door 32 and the connecting members 10 and 20 are rotatably provided on the outer door 31 has been described, but the present invention is not limited to this. For example, the connecting bosses 4 and 14 may be provided on the outer door 31, and the connecting members 10 and 20 may be provided on the inner door 32 so as to be rotatable. That is, the connecting members 10 and 20 can be provided on either the outer door 31 or the inner door 32, and the connecting bosses 4 and 14 can be provided on either the outer door 31 or the inner door 32.

Further, in the above-described embodiment, the case where the first connecting member 10 and the second connecting member 20 have the same shape has been described, but the present invention is not limited to this. For example, the second connecting member 20 may have only two wide portions, a first wide portion 22a and a third wide portion 22f, and a narrow portion only the first narrow portion 22b. Also in this case, since the first connecting member 10 has the first narrow portion 12b and the second narrow portion 12d, it is possible to prevent the inner door 32 from falling from the holding position with a simple configuration and low cost. it can. Further, the number of wide portions and narrow portions may be such that in at least one connecting member, three wide portions and two narrow portions are arranged alternately with the wide portion, and the wider portion is wider than that. And a narrow portion may be provided.

Further, the position holding mechanism of the present invention is applicable not only to an image forming device such as a printer, a fax machine, or a multifunction device, but also to various devices having a second unit movably provided with respect to the first unit. Is.

3 ... Door unit (position holding mechanism), 4 ... First connecting boss (connected portion, first connected portion), 10 ... First connecting member (connecting portion, first connecting portion), 12 ... Slide hole (first slide hole), 12a ... 1st wide portion, 12b ... 1st narrow portion, 12c ... 2nd wide portion, 12d ... 2nd narrow portion, 12e ... inclined portion, 12f ... 3rd wide portion Part, 13 ... recess, 14 ... second connecting boss (connected part, second connected part), 20 ... second connecting member (connecting part, second connecting part), 22 ... slide hole (second 2 slide hole), 22a ... 1st wide portion (4th wide portion), 22b ... 1st narrow portion (3rd narrow portion), 22f ... 3rd wide portion (5th wide portion), 31 ... outside Door (first unit), 32 ... Inner door (second unit), 33a ... First guide unit, 33b ... Second guide unit, 100 ... Image forming device, 101 ... Device body, 101a ... Housing, 140 ... image forming unit, 150 ... fixing device, 164 ... double-sided path (sheet transport path), 165 ... upstream transport path, 166 ... downstream transport path, D2 ... sliding direction, G ... center of gravity position, S ... sheet, W … Width direction.

Claims (9)

The first unit and
A second unit rotatably provided with respect to the first unit,
A connecting portion provided on either one of the first unit and the second unit and provided with a slide hole,
The slide hole is provided on either one of the first unit and the second unit so as to slide the slide hole as the second unit rotates with respect to the first unit. A connected portion connected to the slide hole is provided.
The slide hole includes a first wide portion and a second wide portion in which the length in the width direction orthogonal to the sliding direction in which the connected portion slides is equal to or greater than the length in the width direction of the connected portion. A third wide portion, a first narrow portion provided between the first wide portion and the second wide portion, which is less than the length of the connected portion in the width direction, and the second wide portion. It has a second narrow portion that is provided between the third wide portion and has a length less than the length in the width direction of the connected portion so as to communicate with each other.
A position holding mechanism characterized by that. In the width direction, the length of the second narrow portion is less than the length of the first narrow portion.
The position holding mechanism according to claim 1. Between the third wide portion and the second narrow portion, the length in the width direction is gradually reduced from the third wide portion toward the second narrow portion, and the sliding direction. Has an inclined portion longer than the length of the connected portion in the width direction.
The position holding mechanism according to claim 1 or 2. The connecting portion is continuously formed from the first wide portion to the side opposite to the first narrow portion, and the length in the width direction is less than the length in the width direction of the connected portion. Has a recess,
The position holding mechanism according to any one of claims 1 to 3. The connecting portion is a first connecting portion and is
The connected portion is a first connected portion, and is
The slide hole is a first slide hole.
A second connecting portion provided on either one of the first unit and the second unit and provided with a second slide hole,
It is provided on either one of the first unit and the second unit, and slides in the second slide hole as the second unit rotates with respect to the first unit. As described above, a second connected portion connected to the second slide hole is provided.
The length of the second slide hole in the width direction orthogonal to the sliding direction in which the second connected portion slides is equal to or greater than the length of the second connected portion in the width direction. A fourth wide portion and a fifth wide portion, and a third narrow portion provided between the fourth wide portion and the fifth wide portion and having a length less than the length in the width direction of the second connected portion. , And have
From the initial state in which the first connected portion is located in the third wide portion and the second connected portion is located in the fifth wide portion, the first unit in the rotation axis direction of the second unit. When the edge portion on the connecting portion side is cantilevered and the first connected portion is positioned at the end portion of the first wide portion opposite to the first narrow portion, the second The connected portion of the above is located in the fourth wide portion.
The position holding mechanism according to any one of claims 1 to 4. The edge portion on the side of the first connecting portion in the direction of the rotation axis of the second unit is cantilevered, and the first connected portion is on the side opposite to the first narrow portion of the first wide portion. When the second connected portion is located at the end of the second unit and the second connected portion is located at the fourth wide portion, the cantilever of the second unit is released so that the first connected portion becomes the said. The first wide portion is located at the end on the first narrow portion side, and the second connected portion is located at the end of the fourth wide portion on the third narrow portion side.
The position holding mechanism according to claim 5. The housing of the device body and
An image forming portion housed in the housing and forming a toner image on the sheet,
The position holding mechanism according to any one of claims 1 to 6 is provided.
The first unit is an outer door that is rotatably provided in the housing and can open and close the housing by rotation.
The second unit is an inner door rotatably provided inside the outer door.
In a state in which the inner door is rotated toward the outer door side and closed, a seat transport path is formed between the inner door and the outer door.
When the inner door is rotated to the side away from the outer door and opened, the seat transport path is opened.
An image forming apparatus characterized in that. A fixing device for heating the toner image formed on the sheet and fixing the toner image on the sheet is provided.
The inner door is for forming a first guide portion for forming one side portion of the upstream transport path for carrying the sheet into the fixing device and one side portion of the downstream transport path for carrying out the sheet from the fixing device. Has a second guide section,
The image forming apparatus according to claim 7. The connected portion is provided on the rotation center side of the center of gravity position of the inner door when viewed from the rotation axis direction of the inner door.
The image forming apparatus according to claim 7 or 8.

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