Image forming apparatus

Abstract

To provide an image forming apparatus capable of surely preventing falling by a simple method.SOLUTION: A connection mechanism of an image forming apparatus includes: a lock member 11 having a rotary shaft 31 rotatably supported by a top plate 5X of a lower paper feeder 5L and a lock piece 33 rotated integrally with the rotary shaft 31; two energizing members for energizing the rotary shaft 31 in opposite directions with equal energizing force; and an opening 21 provided in a bottom plate 5Y of an upper paper feeder 5U and through which the lock piece 33 can pass; wherein when the upper and lower paper feeders 5U, 5L are stacked normally, the lock piece 33 passes through the opening 21 and protrudes above the bottom plate 5Y, and when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L, a difference occurs in the energizing forces applied to the rotary shaft 31 by the two energizing members, causing the rotary shaft 31 to rotate and preventing the lock piece 33 from coming out of the opening 21 of the bottom plate 5Y.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus in which an image forming unit is placed on a plurality of paper feeders connected vertically. [Background technology]

[0002] An image forming apparatus in which an image forming unit is placed on top of multiple paper feeders connected vertically has a certain height and, since the center of gravity is located at the top, measures to prevent the apparatus from falling over are necessary. Conventionally, the upper and lower paper feeders have been fixed to each other with screws via connecting members, which resulted in a problem of poor workability.

[0003] As a countermeasure to prevent the device from tipping over, the image forming apparatus described in Patent Document 1 is provided with a locking portion on the paper feeder that is disposed above the base of the main body (corresponding to the image forming unit) with a predetermined gap therebetween and that restricts the upward movement of the main body relative to the paper feeder. This countermeasure to prevent the device from tipping over is said to absorb vibrations applied from the outside because the main body moves relative to the paper feeder within the range of the gap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-247740 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image forming apparatus of Patent Document 1, the locking part is rotated between a restricting position that restricts the upward movement of the main body and a releasing position that releases the restriction by manually operating a lever. Therefore, when there are multiple locking parts or a large number of paper feeders, there is a problem that operability is poor.

[0006] SUMMARY OF THE PRESENT DISCLOSURE In consideration of the above circumstances, an object of the present invention is to provide an image forming apparatus that can be reliably prevented from tipping over using a simple method. [Means for solving the problem]

[0007] In order to achieve the above object, the image forming apparatus of the present invention is an image forming apparatus comprising an image forming unit which forms an image on paper, and a plurality of paper feeders which supply paper to the image forming unit, and the image forming unit is placed on the plurality of paper feeders which are connected in the vertical direction by a connecting mechanism, the connecting mechanism comprising a locking member having a rotation shaft which is rotatably supported on a top plate of the lower paper feeder, and a locking piece which extends in a direction perpendicular to the axial direction of the rotation shaft and rotates integrally with the rotation shaft, two biasing members which bias the rotation shaft in opposite directions with equal biasing forces, and a locking member having a locking piece which locks the rotation shaft and rotates integrally with the rotation shaft, the ... locks the rotation shaft, the locking member having a locking piece which locks the rotation shaft and locks the rotation shaft, the locking member having a locking piece which locks the rotation shaft and locks the rotation shaft, the locking member having a locking piece which locks the rotation shaft, the locking piece which locks the rotation shaft, the locking piece which locks the rotation shaft, the locking The paper feeder is provided with an opening in the bottom plate through which the locking piece can pass, and when the upper paper feeder is stacked normally on the lower paper feeder, the locking piece passes through the opening and protrudes above the bottom plate, and when the upper paper feeder is tilted relative to the lower paper feeder, a difference occurs in the spring forces applied to the rotating shaft from the two spring members, causing the rotating shaft to rotate and preventing the locking piece from coming out of the opening in the bottom plate, and the locking member prevents the upper paper feeder from separating from the lower paper feeder.

[0008] In the present invention, the upper paper feeder may be provided with two interference portions which interfere with the two spring members and increase the spring force when the upper paper feeder is normally stacked on the lower paper feeder, and when the upper paper feeder is tilted relative to the lower paper feeder, one of the interference portions moves away from one of the spring members and the increase in the spring force disappears, resulting in a difference in the spring forces applied to the rotating shaft from the two spring members.

[0009] In the present invention, each of the two biasing members comprises a tension coil spring having one end connected to the rotating shaft, and an arm to one end of which the other end of the tension coil spring is connected and which has a protrusion protruding upward at the other end, and which is rotatably supported on the top plate of the lower paper feeder between both ends, and each of the two interference portions is an opening into which the protrusion of the arm enters, and when the upper paper feeder is stacked normally on the lower paper feeder, the protrusion is pushed by the edge of the opening, causing the arm to rotate, and the tension coil spring is stretched, thereby increasing the biasing force. Effect of the Invention

[0010] According to the present invention, when the upper paper feeder is tilted relative to the lower paper feeder, a difference occurs in the biasing forces applied to the locking member from the two biasing members, and the locking member provided on the lower paper feeder is prevented from coming off the bottom plate of the upper paper feeder. Therefore, even if the image forming device is tilted at a predetermined angle, the image forming device can be prevented from falling over. [Brief description of the drawings]

[0011] [Figure 1] 1 is a front view showing a schematic diagram of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] 4 is a perspective view showing a connecting mechanism provided on upper and lower paper feeders in the image forming apparatus according to one embodiment of the present invention; FIG. [Figure 3A] FIG. 2 is a perspective view, seen from above, of a connecting mechanism (a locking member and two biasing members) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. [Figure 3B] FIG. 2 is a perspective view, seen from below, of a connecting mechanism (a locking member and two biasing members) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. [Figure 4]13 is a bottom view of a connecting mechanism (with a locking member rotated to an initial position) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 5A] 4 is a perspective view showing a connecting mechanism (locking member) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 5B] 1 is a perspective view showing a connecting mechanism (left biasing member) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 5C] 1 is a perspective view showing a connecting mechanism (right biasing member) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 6A] 11 is a side view showing a state before an interference portion provided on an upper paper feeder and a protrusion of an arm member provided on a lower paper feeder interfere with each other in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 6B] 11 is a side view showing a state in which an interference portion provided on an upper paper feeder interferes with a protrusion of an arm member provided on a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 7] 13 is a bottom view of a connecting mechanism (when the biasing force is increased) provided in a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 8] 10 is a front cross-sectional view showing a connecting mechanism when an upper paper feeder is inclined relative to a lower paper feeder in an image forming apparatus according to an embodiment of the present invention. FIG. [Figure 9A] This is a view from below of the connecting mechanism (with the locking member rotated) provided on the lower paper feeder when the upper paper feeder is tilted relative to the lower paper feeder in an image forming apparatus according to one embodiment of the present invention. [Figure 9B]This is an oblique view from above of a connecting mechanism (with the locking member rotated) provided on a lower paper feeder when the upper paper feeder is tilted relative to the lower paper feeder in an image forming apparatus according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to an embodiment of the present invention will now be described with reference to the drawings.

[0013] First, the overall configuration of the image forming apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a front view showing the image forming apparatus 1. Fr, Rr, L, R, U, and Lo shown in each figure respectively indicate the front, rear, left, right, upper, and lower sides of the image forming apparatus.

[0014] The image forming apparatus 1 includes a tandem image forming unit 3 that forms an image on paper, and multiple paper feeders 5 (four in this example) that supply paper to the image forming unit 3. The paper feeders 5 are prepared as optional equipment separately from the image forming apparatus 1. The four paper feeders 5 are stacked vertically. The lower paper feeder 5 and the upper paper feeder 5 are connected to each other by a connection mechanism 9 (not shown in FIG. 1, see FIG. 2, etc.).

[0015] The bottom paper feeder 5 is connected to a dedicated base 7 that is equipped with casters and a support means for stabilizing the installation state. Since the bottom paper feeder 5 is connected to the dedicated base 7, the image forming apparatus 1 is easy to move and does not easily tip over. The image forming units 3 are of a tandem type, and are longer in the depth direction (front-rear direction) than in the width direction (left-right direction). Therefore, when the image forming apparatus 1 is tilted at a predetermined angle (for example, 14 degrees) in the front-rear direction, the center of gravity of the image forming apparatus 1 is within the range of projection of the image forming apparatus 1 onto the floor surface, and the image forming apparatus 1 is unlikely to tip over in the front-rear direction. On the other hand, when the image forming apparatus 1 is tilted at a predetermined angle (for example, 14 degrees) in the left-right direction, the center of gravity of the image forming apparatus 1 is outside the range of projection of the image forming apparatus 1 onto the floor surface. Therefore, the connecting mechanism 9 of this embodiment makes it impossible for the upper and lower paper feeders 5 to separate when tilted left-right, thereby preventing the image forming apparatus 1 from tipping over.

[0016] Next, the connecting mechanism 9 will be described with reference to Figs. 2 to 5. Fig. 2 is a perspective view showing the connecting mechanism 9 provided on the upper and lower paper feeders 5U and 5L. Figs. 3A and 3B are perspective views showing the connecting mechanism 9 (locking member 11, left and right biasing members 13L and 13R) provided on the lower paper feeder 5L. Fig. 4 is a bottom view of the connecting mechanism provided on the lower paper feeder 5L (with the locking member 11 rotated to the initial position). Fig. 5A is a perspective view showing the locking member 11, Fig. 5B is a perspective view showing the left arm 41L of the left biasing member 13L, and Fig. 5C is a perspective view showing the right arm 41R of the right biasing member 13R.

[0017] As shown in Figure 2, the connecting mechanism 9 is composed of a locking member 11 and left and right biasing members 13L, 13R provided on the top plate 5X of the lower paper feeder 5L, a central opening 21 provided on the bottom plate 5Y of the upper paper feeder 5U, and left and right openings 23L, 23R provided on both the left and right sides of the central opening 21.

[0018] First, the lower paper feeder 5L will be described. As described above, the locking member 11 and the left and right biasing members 13L, 13R are supported on the top plate 5X of the lower paper feeder 5L. As shown in Fig. 3A, a circular central through hole 5a is formed in the center of the top plate 5X in the front-rear and left-right directions, and rectangular left and right through holes 5b are formed on both the left and right sides of the central through hole 5a at the same distance from each other.

[0019] 3B, left and right fulcrum pins 5c are provided on the lower surface of the tabletop 5X on the inner side (center side) of the left and right through-holes 5b. Left and right regulating ribs 5d are provided on the lower surface of the tabletop 5X on the inner side of the left and right fulcrum pins 5c. Left and right guide ribs 5e are provided on the lower surface of the tabletop 5X between the left and right regulating ribs 5d and the central through-hole 5a, and are inclined forward.

[0020] Next, the locking member 11 will be described. As shown in FIG. 5A, the locking member 11 has a rotating shaft 31, a locking piece 33 provided at one end of the rotating shaft 31 and extending in a direction intersecting the axial direction of the rotating shaft 31, and a lever piece 35 provided at the other end of the rotating shaft 31 and extending in a direction intersecting the axial direction of the rotating shaft 31. The locking piece 33 has a rectangular parallelepiped shape that is long in the direction intersecting the axial direction, and a central portion in the longitudinal direction is fixed to one end of the rotating shaft 31. The lever piece 35 has a circular base portion 35a and a lever portion 35b that extends from the base portion 35a in a direction parallel to the longitudinal direction of the locking piece 33, and a central portion of the base portion 35a is fixed to the other end of the rotating shaft 31. Two openings 35c are formed at the tip of the lever portion 35b. In this way, the locking piece 33 and the lever piece 35 rotate together with the rotating shaft 31.

[0021] As shown in Fig. 4, the locking member 11 is disposed in a position in which the lever portion 35b of the lever piece 35 faces forward, and the rotating shaft 31 is inserted into the central through-hole 5a of the tabletop 5X. As shown in Fig. 3A, the locking piece 33 protrudes upward from the tabletop 5X, and as shown in Fig. 3B, the lever piece 35 protrudes downward from the tabletop 5X. In this state, the rotating shaft 31 is freely rotatable, and the position of the locking member 11 is not restricted.

[0022] Next, the left and right biasing members 13L and 13R will be described. The left and right biasing members 13L and 13R are formed symmetrically. As shown in FIG. 4, the left and right biasing members 13L and 13R (collectively referred to as biasing members 13) are respectively composed of left and right arms 41L and 41R (collectively referred to as arms 41) and left and right tension coil springs 43L and 43R (collectively referred to as tension coil springs 43). As shown in FIG. 5B and FIG. 5C, the left and right arms 41L and 41R are plate-like members having a rectangular shape in a plan view. At one end of the arm 41, a rectangular parallelepiped projection 51 that projects upward is formed. An inclined surface 51a is formed at the corner between the upper surface of the projection 51 and one side surface. At the other end of the arm 41, an opening 53 is formed. Furthermore, between the projection 51 and the opening 53, an axis hole 55 is formed on the side closer to the projection 51.

[0023] As shown in FIG. 4, the left arm 41L is disposed in such a position that the opening 53 is on the center side and the protrusion 51 is on the left side, and the shaft hole 55 is fitted onto the left fulcrum pin 5c provided on the underside of the tabletop 5X. This allows the left arm 41L to rotate around the fulcrum pin 5c. As shown in FIG. 3A, the protrusion 51 of the left arm 41L protrudes upward from the tabletop 5X through the left through-hole 5b formed in the tabletop 5X. The inclined surface 51a of the protrusion 51 faces backward. The left through-hole 5b has a predetermined length that follows the trajectory of the protrusion 51 when the left arm 41L rotates.

[0024] Similarly, as shown in FIG. 4, the right arm 41R is disposed in such a manner that the opening 53 is on the center side and the protrusion 51 is on the right side, and the shaft hole 55 is fitted onto the right fulcrum pin 5c provided on the underside of the tabletop 5X. This allows the right arm 41R to rotate around the fulcrum pin 5c. As shown in FIG. 3A, the protrusion 51 of the right arm 41R protrudes upward from the tabletop 5X through the right through-hole 5b formed in the tabletop 5X. The inclined surface 51a of the protrusion 51 faces backward. The right through-hole 5b has a predetermined length that follows the trajectory of the protrusion 51 when the right arm 41R rotates.

[0025] 4, the left tension coil spring 43L is suspended along the left guide rib 5e between the opening 53 of the left arm 41L and the opening 35c of the lever piece 35 of the locking member 11. The right tension coil spring 43R is suspended along the right guide rib 5e between the opening 53 of the right arm 41R and the opening 35c of the lever piece 35 of the locking member 11. The spring forces of the left and right tension coil springs 43L, 43R are equal.

[0026] The left tension coil spring 43L biases the left arm 41L to rotate counterclockwise in FIG. 4 (see arrow AL in FIG. 4) when viewed from below. The right tension coil spring 43R biases the right arm 41R to rotate clockwise in FIG. 4 (see arrow AR in FIG. 4) when viewed from below. Here, the rotation of the left arm 41L is restricted by the left-side restricting rib 5d, and the rotation of the right arm 41R is restricted by the right-side restricting rib 5d, so that the left and right arms 41L, 41R are maintained in symmetrical positions in the left-right direction with the central through-hole 5a as the center. In this example, the left and right arms 41L, 41R are maintained in positions along the left-right direction.

[0027] As a result, the left and right tension coil springs 43L, 43R urge the lever piece 35 of the locking member 11 to rotate in opposite directions (see arrows BL, BR in FIG. 4). As described above, the left and right arms 41L, 41R are disposed symmetrically in the left-right direction with respect to the central through-hole 5a, and the urging forces of the left and right tension coil springs 43L, 43R are equal, so that the rotation of the locking member 11 is restricted in a position in which the locking piece 33 is aligned in the front-rear direction (see FIG. 3A) and the lever piece 35 faces forward (see FIG. 3B and FIG. 4). This position of the locking member 11 is referred to as the initial position.

[0028] Next, the upper paper feeder 5U will be described with reference to FIG. 2. As described above, the bottom plate 5Y of the upper paper feeder 5U is formed with a central opening 21 and left and right openings 23L, 23R (collectively referred to as openings 23) provided on both the left and right sides of the central opening 21. The central opening 21 is formed in the approximate center of the bottom plate 5Y in the front-rear and left-right directions. The central opening 21 has a rectangular shape that is long in the front-rear direction. The left and right openings 23L, 23R are formed on the left and right sides of the central opening 21 at equal intervals from the central opening 21. The left and right openings 23L, 23R have a rectangular shape. An inclined surface 23a (see also FIG. 6A and FIG. 6B) is formed at the lower corners of the left and right openings 23L, 23R (corners between the rear side surface and the lower surface of the bottom plate 5Y).

[0029] 2, in the up-down direction, the central opening 21 corresponds to the locking member 11 supported by the lower paper feeder 5L, and the left and right openings 23L, 23R correspond to the protrusions 51 of the left and right arms 41L, 41R of the left and right urging members 13L, 13R supported by the lower paper feeder 5L. Note that the left and right openings 23L, 23R are formed at positions slightly shifted forward relative to the protrusions 51 of the left and right arms 41L, 41R along the rotation trajectory of the protrusions when the left and right arms 41L, 41R rotate.

[0030] The operation of connecting the upper and lower paper feeders 5U, 5L by the connecting mechanism 9 having the above-mentioned configuration will be described with reference to Figures 6A, 6B, and 7. Figures 6A and 6B are side cross-sectional views showing the interference portion (opening 23) and arm 41. Figure 7 is a view of the connecting mechanism 9 (locking member 11 and left and right biasing members 13L, 13R when the biasing force is increased) provided on the lower paper feeder 5L, as viewed from below.

[0031] As shown in FIG. 3A, in the lower paper feeder 5L, the locking member 11 is maintained in the initial position, the locking piece 33 protrudes upward from the top plate 5X, and the protrusions 51 of the left and right arms 41L, 41R protrude upward from the top plate 5X through the left and right through holes 5b, respectively.

[0032] When the upper paper feeder 5U is properly stacked on the lower paper feeder 5L, the locking piece 33 of the locking member 11 passes through the central opening 21 (see FIG. 2) of the bottom plate 5Y of the upper paper feeder 5U and protrudes above the bottom plate 5Y.

[0033] As shown in FIG. 6A, the opening 23 of the bottom plate 5Y of the upper paper feeder 5U is shifted forward with respect to the projection 51 of the arm 41 of the biasing member 13, so that the inclined surface 23a of the opening 23 abuts against the inclined surface 51a of the projection 51 and then descends along the inclined surface 51a. As a result, as shown in FIG. 6B, the inclined surface 51a of the projection 51 is pressed by the inclined surface 23a of the opening 23, and the projection 51 moves forward within the through hole 5b of the top plate 5X, causing the arm 41 to rotate. When viewed from below, as shown in FIG. 7, the left arm 41L rotates in the clockwise direction (see arrow CL) and the right arm 41R rotates in the counterclockwise direction (see arrow CR). The left and right arms 41L and 41R rotate by the same amount. Furthermore, the left and right protrusions 51 pass through the left and right openings 23L, 23R (see FIG. 2) of the upper paper feeder 5U and protrude upward from the bottom plate 5Y.

[0034] As a result, the left and right tension coil springs 43L, 43R are stretched, and the force biasing the lever piece 35 in the opposite directions increases. Thus, the left and right openings 23L, 23R provided in the bottom plate 5Y are an example of two interference parts that interfere with the two biasing members 13L, 13R to increase the biasing force when the upper paper feeder 5U is normally stacked on the lower paper feeder 5L. Since the increase in the biasing forces of the left and right tension coil springs 43L, 43R is equal, the locking member 11 continues to be maintained in the initial position. In addition, the locking piece 33 of the locking member 11 of the top plate 5X and the protrusions 51 of the left and right biasing members 13L, 13R are inserted into the central opening 21 and the left and right openings 23L, 23R of the bottom plate 5Y, respectively, to connect the upper and lower paper feeders 5U, 5L.

[0035] Next, the operation of the connecting mechanism 9 when the image forming apparatus 1 is tilted to the left will be described with reference to Figs. 8, 9A, and 9B. Fig. 8 is a front cross-sectional view showing the connecting mechanism 9 when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L. Fig. 9A is a view of the locking member 11 and the left and right urging members 13L, 13R from below when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L, and Fig. 9B is a perspective view of the locking member 11 and the left and right urging members 13L, 13R (protrusions 51) from above when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L.

[0036] When the image forming apparatus 1 tilts leftward (see the two-dot chain line in FIG. 1) after the upper paper feeder 5U is normally connected to the lower paper feeder 5L, for example, as shown in FIG. 8, the third paper feeder 5U from the top tilts leftward relative to the bottom paper feeder 5L. That is, the bottom plate 5Y of the third paper feeder 5U from the top tilts leftward relative to the top plate 5X of the bottom paper feeder 5L, and a gap is created between the top plate 5X and the bottom plate 5Y. The gap gradually widens from the right side to the left side. In one example, when the tilt angle of the upper paper feeder 5U relative to the lower paper feeder 5L is 1 degree, a maximum gap of 6.5 mm is created.

[0037] 8, on the left side where the gap is narrower, the projection 51 of the left biasing member 13L remains inserted into the left opening 23L, while on the right side where the gap is wider, the projection 51 of the biasing member 13R comes out of the right opening 23L.

[0038] As a result, the force (increase in the biasing force) biasing the right arm 41R by the right opening 23R disappears, and the biasing force applied from the right tension coil spring 43R to the lever piece 35 becomes weaker than the biasing force applied from the left tension coil spring 43L to the lever piece 35. Then, as shown in FIG. 9A, the right arm 41R rotates clockwise (see arrow DR) until it abuts against the right restriction rib 5d, and the lever piece 35 is biased by the left biasing member 13L, so that the locking member 11 rotates from the initial position in the counterclockwise direction (see arrow E) as viewed from below. This prevents the locking piece 33 from coming off the central opening 21 of the bottom plate 5Y, as shown in FIG. 9B. In other words, the upper paper feeder 5U is prevented from separating from the lower paper feeder 5L.

[0039] As mentioned above, the bottom paper feeder 5 is supported by a movable dedicated stand 7 to prevent it from tipping over, and by making the upper and lower paper feeders 5U, 5L unable to separate in this manner, the image forming apparatus 1 is prevented from tipping over.

[0040] Furthermore, when the paper feeders 5 are stacked normally, the locking piece 33 of the locking member 11 is not prevented from coming out of the central opening 21, so that by lifting the upper paper feeder 5U, it can be easily removed from the lower paper feeder 5L.

[0041] As described above, according to the present invention, when the image forming apparatus 1 is tilted, the upper and lower paper feeders 5U, 5L are automatically connected by the connection mechanism 9 so that they cannot be separated. Specifically, when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L, a difference occurs in the urging forces applied to the locking member 11 by the left and right urging members 13L, 13R, causing the locking member 11 to rotate and preventing the locking piece 33 from coming out of the central opening 21 of the bottom plate 5Y, thereby connecting the upper and lower paper feeders 5U, 5L so that they cannot be separated. Therefore, even if the image forming apparatus 1 is tilted at a predetermined angle, it is possible to prevent the image forming apparatus 1 from falling over.

[0042] Furthermore, when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L, a difference is created in the gap between the bottom plate 5Y and the top plate 5X in the tilt direction (left-right direction), which reliably creates a difference in the biasing forces applied by the left and right interference portions 23L, 23R to the left and right biasing members 13L, 13R, so that the locking member 11 can be rotated more quickly.

[0043] Furthermore, since the interference portion is the left and right openings 23L, 23R formed in the bottom plate 5Y of the upper paper feeder 5U, there is no need to secure space in the vertical direction to arrange a configuration that creates a difference in the biasing forces of the left and right biasing members 13L, 13R.

[0044] In this embodiment, as described above, the coupling mechanism 9 for the image forming apparatus 1 having a structure that is easily tilted in the left-right direction has been described. That is, the coupling mechanism 9 is adapted to operate in response to the left-right tilt of the bottom plate 5Y of the upper paper feeder 5U relative to the top plate 5X of the lower paper feeder 5L. Specifically, a difference occurs in the operation of the left and right arms 41L, 41R in response to the left-right tilt, and this difference connects the upper and lower paper feeders 5U, 5L in an inseparable manner. For this reason, for example, in the case of an image forming apparatus 1 having a structure that is easily tilted in the front-rear direction, the coupling mechanism 9 is provided to operate in response to the front-rear tilt of the bottom plate 5Y of the upper paper feeder 5U relative to the top plate 5X of the lower paper feeder 5L. For example, the coupling mechanism of this embodiment may be arranged in a position rotated 90 degrees in a plan view, and the lock member 11 may be rotated by the difference in the operation of the front and rear urging members corresponding to the left and right urging members 13L, 13R, to prevent it from coming off the bottom plate 5Y of the upper paper feeder 5U.

[0045] Although the present invention has been described with respect to a specific embodiment, the present invention is not limited to the above embodiment. The above embodiment may be variously changed, substituted, or modified without departing from the scope and spirit of the present invention, and the claims include all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0046] 1 Image forming device 1 3 Image forming unit 5(5U, 5L) Paper Feeder 9 Connection mechanism 11 (11L, 11R) Locking member 13 (13L, 13R) Urging member 21 Central opening (opening) 23 (23L, 23R) Left and right openings (interference area) 31 Rotation axis 33 Lock piece 41(41L, 41R) Arm 43 (43L, 43R) Tension coil spring 51 protrusion

Claims

1. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a plurality of paper feeders that supply sheets to the image forming unit, the image forming unit being placed on the plurality of paper feeders that are vertically connected by a connecting mechanism, The connecting mechanism includes: a locking member including a rotation shaft rotatably supported on a top plate of the lower paper feeder and a locking piece extending in a direction perpendicular to the axial direction of the rotation shaft and rotating integrally with the rotation shaft; Two biasing members biasing the rotating shaft in opposite directions with equal biasing forces; an opening provided in a bottom plate of the upper paper feeder through which the lock piece can pass; When the upper paper feeder is properly stacked on the lower paper feeder, the lock piece passes through the opening and protrudes above the bottom plate, An image forming apparatus characterized in that, when the upper paper feeder is tilted relative to the lower paper feeder, a difference occurs in the spring forces applied to the rotating shaft from the two spring members, causing the rotating shaft to rotate and the locking piece to be prevented from coming out of the opening in the bottom plate, and the locking member prevents the upper paper feeder from separating from the lower paper feeder.

2. the upper paper feeder includes two interference portions that interfere with the two biasing members to increase the biasing force when the upper paper feeder is normally stacked on the lower paper feeder, An image forming apparatus as described in claim 1, characterized in that when the upper paper feeder is tilted relative to the lower paper feeder, one of the interference portions separates from one of the urging members and the increase in the urging force disappears, resulting in a difference in the urging forces applied to the rotating shaft from the two urging members.

3. Each of the two biasing members is A tension coil spring having one end connected to the rotating shaft; an arm having one end to which the other end of the tension coil spring is connected and having a protrusion protruding upward at the other end, the arm being rotatably supported between both ends on a top plate of the lower paper feeder, The image forming apparatus described in claim 2, characterized in that each of the two interference portions is an opening into which the protrusion of the arm enters, and when the upper paper feeder is normally stacked on the lower paper feeder, the protrusion is pushed by the edge of the opening, causing the arm to rotate, and the tension coil spring is stretched, thereby increasing the spring force.

Images