Image forming apparatus

Abstract

To provide an image forming apparatus capable of surely preventing falling by a simple method.SOLUTION: A connecting mechanism 9 of an image forming apparatus includes: two pins 11 erected on a top plate 5X of a lower paper feeder 5L; a pin guide 13 which has a cylindrical body 21 externally fitted onto the two pins 11 and is movable between an upper position where the cylindrical body 21 abuts against a head part 11b of the pins 11 and a lower position where the cylindrical body 21 is spaced downward from the head part 11b; and two cylindrical parts 15 which are provided on a bottom plate 5Y of the upper paper feed 5U and into which the two pins 11 can be inserted; and a lock member 17 supported by the cylindrical parts 15; wherein when the upper paper feeder 5U is inclined, one of the lock members 17 moves upward together with the other of the cylindrical parts 15, the lock member 17 is inserted between the head part 11b and the cylindrical body 21, thereby preventing the pins 11 from coming out of the cylindrical parts 15.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 in a vertical direction. [Background technology]

[0002] An image forming apparatus in which an image forming unit is placed on 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 creates 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 the locking parts are provided in multiple locations or when there are many paper feeders, there is a problem that operability is deteriorated.

[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, an 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, the image forming unit being placed on the plurality of paper feeders which are connected in the vertical direction by a connecting mechanism, the connecting mechanism comprising: two pins which are erected at a predetermined interval from the top plate of the lower paper feeder, each having an axis portion and a head portion provided at the upper end of the axis portion; a cylinder which is fitted onto each of the axis portions of the two pins, and a bar which connects the cylinder portions, the pin guide being movable in the vertical direction between an upper position where the cylinder portion abuts against the head portion and a lower position where the cylinder portion is spaced downward from the head portion; two cylindrical portions which are provided on the bottom plate of the upper paper feeder, into which the two pins can each be inserted; and two locking members having two locking pieces supported so as to be biased toward the inside of the cylindrical portions along a direction intersecting the axial direction of the cylindrical portions, and when the upper paper feeder is stacked on the lower paper feeder and the two pins are inserted into the two cylindrical portions, the locking members engage the cylindrical portions with the tube of the pin guide, connecting the upper paper feeder to the lower paper feeder, and when the upper paper feeder is tilted relative to the lower paper feeder, one of the locking members moves upward together with one of the cylindrical portions, and the locking pieces of the locking member fit between the head of the pin and the tube of the pin guide, preventing the pin from coming out of the cylindrical portions and preventing the upper paper feeder from separating from the lower paper feeder.

[0008] In the present invention, after the upper paper feeder is stacked on the lower paper feeder and the two pins are inserted into the two cylindrical portions, when the upper paper feeder is lifted from the lower paper feeder, the pin guide moves upward together with the cylindrical portions and the two cylindrical bodies of the pin guide abut the head portions of the two pins, and then the locking pieces of the two locking members move upward while moving in opposite directions from the cylindrical bodies along the head portions, thereby releasing the engagement of the cylindrical portions of the pin guide to the cylindrical bodies by the locking members, and the upper paper feeder may be detached from the lower paper feeder.

[0009] In the present invention, the head portion of the pin may be formed so that its outer diameter increases downward, and the upper portion of the cylindrical body of the pin guide may be formed so that its outer diameter increases upward, and the maximum outer diameter of the head portion and the maximum outer diameter of the cylindrical body may be equal.

[0010] In the present invention, the opposing surfaces of the two locking pieces of the locking member may be inclined downward. Effect of the Invention

[0011] According to the present invention, when the upper paper feeder is tilted relative to the lower paper feeder and the locking member moves upward by a predetermined height, the locking member automatically engages with the pin to prevent the upper and lower paper feeders from separating. Therefore, even if the image forming device is tilted at a predetermined angle, it is possible to prevent the image forming device from falling over. [Brief description of the drawings]

[0012] [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. [Diagram 3]5 is a cross-sectional view showing left and right pins and pin guides of a connecting mechanism for a lower paper feeder in an image forming apparatus according to one embodiment of the present invention. FIG. [Figure 4A] 10A to 10C are side views showing a procedure for attaching pin guides to two pins in an image forming apparatus according to one embodiment of the present invention. [Figure 4B] 10A to 10C are side views showing a procedure for attaching pin guides to two pins in an image forming apparatus according to one embodiment of the present invention. [Figure 4C] 10A to 10C are side views showing a procedure for attaching pin guides to the two lower pins in the image forming apparatus according to one embodiment of the present invention. [Diagram 5] 5 is a cross-sectional view showing a locking member of a connecting mechanism of an upper paper feeder in the image forming apparatus according to one embodiment of the present invention. FIG. [Figure 6A] 4 is a cross-sectional view showing a connection mechanism before upper and lower paper feeders are connected to each other in the image forming apparatus according to one embodiment of the present invention. FIG. [Figure 6B] 5 is a cross-sectional view showing a connecting mechanism after upper and lower paper feeders are connected in the image forming apparatus according to one embodiment of the present invention. FIG. [Figure 7A] 5A and 5B are cross-sectional views illustrating a connecting operation between upper and lower paper feeders by a connecting mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 7B] 5A and 5B are cross-sectional views illustrating a connecting operation between upper and lower paper feeders by a connecting mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 7C] 5A and 5B are cross-sectional views illustrating a connecting operation between upper and lower paper feeders by a connecting mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 7D] 5A and 5B are cross-sectional views illustrating a connecting operation between upper and lower paper feeders by a connecting mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 8] 1 is a cross-sectional view showing a state in which 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; [Figure 9A]11 is a cross-sectional view showing the left connecting mechanism when the upper paper feeder is inclined relative to the lower paper feeder in the image forming apparatus according to one embodiment of the present invention. FIG. [Figure 9B] 11 is a cross-sectional view showing the right-side connecting mechanism when the upper paper feeder is inclined relative to the lower paper feeder in the image forming apparatus according to one embodiment of the present invention. FIG. [Figure 10A] 11A and 11B are cross-sectional views illustrating an operation of disconnecting the upper and lower paper feeders by the connection mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 10B] 11A and 11B are cross-sectional views illustrating an operation of disconnecting the upper and lower paper feeders by the connection mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 10C] 11A and 11B are cross-sectional views illustrating an operation of disconnecting the upper and lower paper feeders by the connection mechanism in the image forming apparatus according to one embodiment of the present invention. [Figure 10D] 11A and 11B are cross-sectional views illustrating an operation of disconnecting the upper and lower paper feeders by the connection mechanism in the image forming apparatus according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 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.

[0014] First, the overall configuration of an image forming apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a front view showing the image forming apparatus. The image forming apparatus includes a tandem image forming unit that forms an image on paper, and a plurality of paper feeders (four in this example) that supply paper to the image forming unit. The paper feeders are prepared as optional devices separately from the image forming apparatus. The four paper feeders are stacked vertically. The lower paper feeder and the upper paper feeder are connected to each other by a connecting mechanism.

[0015] The bottom paper feeder is connected to a dedicated stand equipped with casters and a support means for stabilizing the installation state. Since the bottom paper feeder is connected to the dedicated stand 7, the image forming apparatus 1 is easy to move and does not easily tip over. The image forming units 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 is tilted at a predetermined angle (e.g., 14 degrees) in the front-rear direction, the center of gravity of the image forming apparatus is within the range of projection of the image forming apparatus onto the floor surface, and the image forming apparatus is not easily toppled in the front-rear direction. On the other hand, when the image forming apparatus is tilted at a predetermined angle (e.g., 14 degrees) in the left-right direction, the center of gravity of the image forming apparatus is outside the range of projection of the image forming apparatus onto the floor surface. Therefore, the connection mechanism of this embodiment makes it impossible for the upper and lower paper feeders to separate when tilted left-right, preventing the image forming apparatus from tipping over.

[0016] Next, the connecting mechanism 9 will be described with reference to Fig. 2. Fig. 2 is a perspective view showing the connecting mechanism 9 provided on the upper and lower paper feeders 5U, 5L. The connecting mechanism 9 includes left and right pins 11L, 11R (collectively referred to as pins 11) provided on the top plate 5X of the lower paper feeder 5L, a pin guide 13 that spans between the left and right pins 11L, 11R, left and right cylindrical portions 15L, 15R (collectively referred to as cylindrical portions 15) that are provided on the bottom plate 5Y of the upper paper feeder 5U and into which the left and right pins 11L, 11R are inserted, and left and right locking members 17 (not shown in Fig. 2, see Fig. 5; collectively referred to as locking members 17) supported by the left and right cylindrical portions 15L, 15R.

[0017] First, the lower paper feeder 5L will be described with reference to FIG. 3. FIG. 3 is a cross-sectional view showing the left and right pins 11L, 11R and the pin guide 13. As shown in FIG. 2, the left and right pins 11L, 11R are erected at a predetermined interval in the left-right direction at the rear end of the top plate 5X of the lower paper feeder 5L. As shown in FIG. 3, the pin 11 has a cylindrical shaft portion 11a and a head portion 11b provided at the upper end of the shaft portion 11a. The head portion 11b is trapezoidal in cross-section and expands in diameter downward. The outer diameter of the lower end surface of the head portion 11b is larger than the outer diameter of the shaft portion 11a.

[0018] Next, the pin guide 13 will be described. As shown in Fig. 3, the pin guide 13 has left and right cylindrical bodies 21L, 21R (collectively referred to as cylindrical bodies 21) fitted onto the shaft portions 11a of the left and right pins 11L, 11R, and a bar 23 connecting the left and right cylindrical bodies 21L, 21R. The cylindrical body 21 has a lower portion 21a with a constant outer diameter and an upper portion 21b with an outer diameter that increases upward. The maximum outer diameter of the upper portion 21b (the upper end surface of the cylindrical body 21) is equal to the outer diameter of the lower end surface of the head portion 11b of the pin 11.

[0019] The pin guide 13 is movable in the vertical direction between an upper position where the upper end surface of the upper portion 21b of the cylindrical body 21 abuts against the lower surface of the head portion 11b, and a lower position where the cylindrical body 21 abuts against the top plate 5X. When the pin guide 13 moves to the upper position and the upper end surface of the upper portion 21b of the cylindrical body 21 abuts against the lower surface of the head portion 11b, the outer circumferential surface of the upper portion 21b of the cylindrical body 21 and the outer circumferential surface of the head portion 11b become continuous. When the pin guide 13 moves to the lower position, a gap of a predetermined height is formed between the lower end surface of the head portion 11b of the pin 11 and the upper end surface of the cylindrical body 21.

[0020] Next, referring to FIG. 4A to FIG. 4C, a procedure for attaching the pin guide 13 to the left and right pins 11L and 11R will be described. FIG. 4A to FIG. 4C are cross-sectional views showing the left and right pins 11L and 11R, the pin guide 13, and the lower paper feeder 5L. As shown in FIG. 4A, the left and right pins 11L and 11R and the pin guide 13 are prepared separately from the lower paper feeder 5L. First, as shown in FIG. 4B, the pin guide 13 is placed at a predetermined position on the top plate 5X of the lower paper feeder 5L. Then, as shown in FIG. 4C, the left and right pins 11L and 11R are inserted from above into the left and right cylinders 21L and 21R of the pin guide 13. Then, the left and right pins 11L and 11R are fixed to the top plate 5X by crimping or using a fixing pin. As a result, the pin guide 13 is supported so as to be movable along the left and right pins 11L and 11R as described above.

[0021] Next, the upper paper feeder 5U will be described. As shown in Fig. 2, the bottom plate 5Y of the upper paper feeder 5U has left and right openings 5a formed therein corresponding to the left and right pins 11L, 11R provided on the top plate 5X of the lower paper feeder 5L. The top surface of the bottom plate 5Y has left and right cylindrical portions 15L, 15R formed along the left and right openings 5a. The cylindrical portions 15L, 15R have an inner diameter that allows the pins 11 to be inserted therein.

[0022] Next, the locking member 17 will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing the locking member 17. Two through holes 15a, each having a rectangular cross section, are formed diagonally on the lower end of the cylindrical portion 15. The locking member 17 is supported by the two through holes 15a.

[0023] The locking member 17 has two locking pieces 31. Each locking piece 31 is a rectangular parallelepiped that is long in the left-right direction, and one end face 31a is inclined downward. The two locking pieces 31 are inserted into the two through holes 15a of the cylindrical portion 15 with the inclined end face 31a facing the hollow portion of the cylindrical portion 15. The inclined end faces 31a of the two locking pieces 31 face each other.

[0024] The outer openings of the two through holes 15a of the cylindrical portion 15 are closed by closing plates 15b. A through hole is formed in the closing plate 15b. A screw 33 is inserted from the outside into the through hole of the closing plate 15b. The screw 33 is fastened to a locking piece 31. The locking piece 31 moves together with the screw 33 between a locking position where it protrudes into the hollow portion of the cylindrical portion 15 and a retracted position where it is separated from the hollow portion. A coil spring 35 is disposed between the closing plate 15b and the locking piece 31. The coil spring 35 biases the locking piece 31 to the locking position. The head of the screw 33 abuts against the closing plate 15b to prevent the locking piece 31 from falling out of the through hole 15a.

[0025] 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 7A to 7D. Figures 6A and 6B are cross-sectional views showing the connecting mechanism 9 before and after the upper and lower paper feeders 5U, 5L are connected. Figures 7A to 7D are cross-sectional views explaining the connecting operation of the upper and lower paper feeders 5U, 5L by the connecting mechanism 9.

[0026] As shown in Fig. 6A, when the upper paper feeder 5U is stacked on the lower paper feeder 5L, the left and right pins 11L, 11R of the lower paper feeder 5L are relatively inserted into the hollow portions of the left and right cylindrical portions 15L, 15R through the left and right openings 5a of the bottom plate 5Y of the upper paper feeder 5U as shown in Fig. 6B. Furthermore, the left and right locking members 17L, 17R are locked to the left and right cylindrical bodies 21L, 21R of the pin guide 13.

[0027] A detailed description will be given below. In the lower paper feeder 5L, the pin guide 13 has moved to a lower position due to its own weight, so that a space is provided between the head portion 11b of the pin 11 and the cylindrical body 21. In the locking member 17, the two locking pieces 31 have moved to the locking position. When the upper paper feeder 5U is stacked on the lower paper feeder 5L, the cylindrical body 21 moves downward toward the pin 11. First, as shown in FIG. 7A, the pin 11 is relatively inserted into the cylindrical portion 15. Then, the inclined end faces 31a of the two locking pieces 31 of the locking member 17 come into contact with the outer circumferential surface of the head portion 11b. Then, as the cylindrical portion 15 moves downward, the two locking pieces 31 are guided outward along the outer circumferential surface of the head portion 11b and move in opposite directions.

[0028] 7B, when the two locking pieces 31 reach the space between the head portion 11b and the cylindrical body 21, the two locking pieces 31 are biased by the coil spring 35 and move in a direction toward each other. Then, the two locking pieces 31 enter the gap between the lower end surface of the head portion 11b and the upper end surface of the cylindrical body 21, and move downward through this gap. Then, the inclined end surfaces 31a of the two locking pieces 31 eventually come into contact with the corner between the upper end surface and the side surface of the cylindrical body 21.

[0029] When the cylindrical portion 15 moves further downward, as shown in FIG. 7C, the inclined end faces 31a of the two locking pieces 31 are pushed outward by the corners between the upper end face and the side face of the cylindrical body 21 and move in opposite directions.

[0030] When the cylindrical portion 15 moves further downward, as shown in Fig. 7D, the inclined end faces 31a of the two locking pieces 31 move downward away from the corner between the upper end face and the side face of the cylindrical body 21, and the tips of the two locking pieces 31 move downward along the outer circumferential surface of the cylindrical body 21. Eventually, the bottom plate 5Y of the upper paper feeder 5U abuts against the top plate 5X of the lower paper feeder 5L. Here, the two locking pieces 31 are biased inward by the coil spring 35 and abut against the cylindrical body 21 with a predetermined pressure. As a result, the locking member 17 is engaged with the cylindrical body 21, and the upper and lower paper feeders 5U and 5L are connected.

[0031] Next, the operation of the connecting mechanism 9 when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L will be described with reference to Figures 8, 9A and 9B. Figure 8 is a cross-sectional view showing the connecting mechanism 9 when tilted, and Figures 9A and 9B are cross-sectional views showing the left and right locking members 17L, 17R when tilted.

[0032] 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.

[0033] 9A, on the left side where the gap is narrow, the distance between the bottom plate 5Y of the upper paper feeder 5U and the top plate 5X of the lower paper feeder 5L is very short, so the left cylindrical portion 15L hardly moves upward and the left locking member 17L remains locked to the cylinder 21. In other words, the pin guide 13 does not move from the lower position.

[0034] On the other hand, as shown in Fig. 9B, on the left side where the gap is wider, the distance between the bottom plate 5Y and the top plate 5X is longer. Therefore, the right cylindrical portion 15R moves upward from the top plate 5X, and the right locking member 17R also moves upward together with the right cylindrical portion 15R. However, as described above, since the pin guide 13 has not moved from the lower position, a gap is left between the lower surface of the head portion 11b of the right pin 11 and the upper surface of the right cylinder 21R. Therefore, the two lock pieces 31 of the right locking member 17R move upward along the right cylinder 21R.

[0035] Then, when the two lock pieces 31 of the right lock member 17R reach the gap between the head portion 11b of the right pin 11R and the right cylinder 21R, the two lock pieces 31 are biased by the coil spring 35 and enter the gap. As a result, the two lock pieces 31 are engaged with the underside of the head portion 11b, restricting the upward movement of the right cylinder 15R. In other words, the upper paper feeder 5U is prevented from separating from the lower paper feeder 5L. The upper and lower paper feeders 5U, 5L cannot be separated in this manner, thereby preventing the image forming apparatus 1 from tipping over.

[0036] Next, the operation of releasing the connection between the upper paper feeder 5U and the lower paper feeder 5L by the connection mechanism 9 will be described with reference to Figures 10A to 10D. Figures 10A to 10D are cross-sectional views showing the lock member 17.

[0037] 10A, the tips of the two locking pieces 31 of the locking member 17 are in contact with the outer circumferential surface of the boundary between the lower portion 21a and the upper portion 21b of the cylinder 21 with a predetermined pressure. Therefore, when the upper paper feeder 5U is moved upward, the left and right locking members 17L, 17R supported by the left and right cylindrical portions 15L, 15R also move upward together with the upper paper feeder 5U, and the left and right cylinders 21L, 21R against which the left and right locking members 17L, 17R are in contact with a predetermined pressure also move upward. In other words, the pin guide 13 also moves upward.

[0038] 10B, the pin guide 13 moves upward until the upper end surface of the cylindrical body 21 abuts against the lower end surface of the head portion 11b of the pin 11. As described above, the outer diameters of the upper end surface of the cylindrical body 21 and the lower end surface of the head portion 11b are equal, so that the outer circumferential surface of the upper portion 21b of the cylindrical body 21 and the outer circumferential surface of the head portion 11b are smoothly connected. When the upper end surface of the cylindrical body 21 abuts against the lower end surface of the head portion 11b in this manner, the upward movement of the cylindrical body 21 is restricted.

[0039] Meanwhile, as shown in Fig. 10C, the tips of the two locking pieces 31 of the locking member 17 move from the cylindrical body 21 to the head portion 11b of the pin 11, and the locking member 17 moves away from the cylindrical body 21. Then, as shown in Fig. 10D, the cylindrical body 21, i.e., the pin guide 13, moves to a lower position by its own weight. Also, the locking pieces 31 are urged to the locked position and move upward along the head portion 11b of the pin 11. Then, the pin 11 comes out of the cylindrical portion 15. This releases the connection between the upper and lower paper feeders 5U and 5L.

[0040] As described above, according to the present invention, even if the image forming apparatus 1 is tilted, the upper and lower paper feeders 5U, 5L are automatically kept unable to separate by the connecting mechanism 9, so that the image forming apparatus 1 can be prevented from tipping over. Specifically, when the upper paper feeder 5U is tilted relative to the lower paper feeder 5L and one of the locking members 17 moves upward by a predetermined height, the locking member 17 automatically engages with the pin 11, preventing the upper and lower paper feeders 5U, 5L from separating. Therefore, even if the image forming apparatus 1 is tilted at a predetermined angle, the image forming apparatus 1 can be prevented from tipping over.

[0041] On the other hand, when the upper paper feeder 5U is lifted from the lower paper feeder 5L, the left and right locking members 17L, 17R move upward together with the left and right cylindrical portions 15L, 15R. Then, the pin guide 13 also moves upward together with the left and right locking members 17L, 17R, and the left and right cylinders 21L, 21R come into contact with the head portions 11b of the left and right pins 11L, 11R. The left and right locking members 17L, 17R move smoothly from the left and right cylinders 21L, 21R of the pin guide 13 to the head portions 11b of the left and right pins 11L, 11R, and eventually move away from the left and right pins 11L, 11R. Therefore, by lifting the upper paper feeder 5U from the lower paper feeder 5L, the connection between the two can be easily released.

[0042] In addition, since the maximum outer diameter of the head portion 11b is equal to that of the cylindrical body 21, when the left and right cylindrical bodies 21L, 21R abut against the head portions 11b of the left and right pins 11L, 11R, their outer circumferential surfaces connect smoothly. Therefore, the two locking pieces 31 of the locking member 17 can move smoothly from the cylindrical body 21 to the head portions 11b.

[0043] In this embodiment, as described above, the connecting mechanism 9 for the image forming apparatus 1 having a structure that easily tilts in the left-right direction has been described. That is, the two pins 11 and the two cylindrical portions 15 of the connecting mechanism 9 are arranged spaced apart from each other in the left-right direction. However, for example, in the case of an image forming apparatus 1 having a structure that easily tilts in the front-rear direction, the two pins 11 and the two cylindrical portions 15 of the connecting mechanism 9 may be arranged spaced apart from each other in the front-rear direction, and a pin guide 13 may be provided between both pins 11.

[0044] 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]

[0045] 1. Image forming device 3 Image forming unit 5(5U, 5L) Paper Feeder 9 Connection mechanism 11(11L, 11R) pin 13 Pin guide An image forming unit that forms an image on a sheet, 15(15L, 15R) Cylindrical section 17 (17L, 17R) Locking member 21(21L, 21R) Cylindrical body 23 Bar 31 Lock piece

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: Two pins, each having a shaft portion and a head portion provided at the upper end of the shaft portion, are provided on the top plate of the lower paper feeder at a predetermined interval, a pin guide including a cylinder fitted onto each of the shaft portions of the two pins and a bar connecting the cylinders, the pin guide being movable in the vertical direction between an upper position where the cylinders abut against the head portions and a lower position where the cylinders are spaced downward from the head portions; two cylindrical portions provided on a bottom plate of the upper paper feeder, into which the two pins can be inserted respectively; two locking members each having two locking pieces supported on each of the two cylindrical portions so as to be biased toward the inside of the cylindrical portions along a direction intersecting an axial direction of the cylindrical portions; When the upper paper feeder is stacked on the lower paper feeder and the two pins are inserted into the two cylindrical portions, the cylindrical portions are locked to the tube of the pin guide by the locking member, and the upper paper feeder is connected to the lower paper feeder, An image forming apparatus characterized in that, when the upper paper feeder is tilted relative to the lower paper feeder, one of the locking members moves upward together with one of the cylindrical portions, and the locking piece of the locking member enters between the head portion of the pin and the cylindrical body of the pin guide, preventing the pin from coming out of the cylindrical portion and preventing the upper paper feeder from separating from the lower paper feeder.

2. When the upper paper feeder is stacked on the lower paper feeder and the two pins are inserted into the two cylindrical portions, the upper paper feeder is lifted up from the lower paper feeder, The image forming apparatus described in claim 1, characterized in that the pin guide moves upward together with the cylindrical portion, so that the two cylindrical bodies of the pin guide abut the head portions of the two pins, and then the locking pieces of the two locking members move upward while moving from the cylindrical bodies along the head portions in opposite directions to each other, thereby releasing the engagement of the cylindrical portion of the pin guide to the cylindrical bodies by the locking members, and the upper paper feeder is separated from the lower paper feeder.

3. The head portion of the pin is formed so that the outer diameter increases downward, The upper portion of the cylindrical body of the pin guide is formed so that the outer diameter increases upward, 3. The image forming apparatus according to claim 2, wherein the maximum outer diameter of the head portion is equal to the maximum outer diameter of the cylindrical body.

4. 2. The image forming apparatus according to claim 1, wherein the opposing surfaces of the two locking pieces of the locking member are inclined downward.

Images