Image forming apparatus

Abstract

To provide an image forming apparatus that can reliably prevent its falling with a simple method.SOLUTION: A connection mechanism of an image forming apparatus comprises: two rotatable shafts 11L, 11R that are arranged on a top plate of a lower paper feeder 5L at a predetermined interval and are rotatable around an axis along a vertical direction; spiral grooves 35 that are formed on outer peripheral surfaces of the two shafts 11L, 11R; a cable that connects the two shafts 11L, 11R to each other and rotates the shafts in the same direction in synchronization with each other; two openings 13L, 13R that are provided in a bottom plate of an upper paper feeder 5U, and into which the two shafts 11L, 11R are inserted; and pins 71 that project from opening edges to the inside of the two openings 13L, 13R, and are engaged with the spiral grooves 35 of the two shafts 11L, 11R. The rotation of only one shaft of the two shafts 11L, 11R is regulated by the cable.SELECTED DRAWING: Figure 8A

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 the vertical direction.

Background Art

[0002] An image forming apparatus in which an image forming unit is placed on a plurality of paper feeders connected in the vertical direction has a predetermined height and further has a center of gravity located upward, so that measures for preventing tipping are required. Conventionally, since the upper and lower paper feeders were fixed to each other with screws via a connecting member, there has been a problem of poor workability.

[0003] As a measure for preventing tipping, the image forming apparatus described in Patent Document 1 is provided with a locking portion that is disposed above the base of the main body portion (corresponding to the image forming unit) with a predetermined gap above the paper feeder, and restricts upward movement of the main body portion with respect to the paper feeder. In this anti-tipping measure, since the main body portion moves with respect to the paper feeder within the range of the gap, it is said that vibrations applied from the outside are absorbed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the image forming apparatus of Patent Document 1, the locking portion is rotated by manually operating a lever between a regulating position for restricting upward movement of the main body portion and a releasing position for releasing the restriction. For this reason, when the locking portions are provided at a plurality of locations or the number of paper feeders is large, there is a problem that workability deteriorates.

[0006] Therefore, in view of the above circumstances, an object of the present invention is to provide an image forming apparatus that can surely prevent falls in a simple manner.

Means for Solving the Problems

[0007] To achieve the above object, an image forming apparatus of the present invention includes 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, and is an image forming apparatus in which the image forming unit is placed on the plurality of paper feeders connected vertically by a connecting mechanism, wherein the connecting mechanism includes two shafts that are arranged at a predetermined interval on the top plate of the lower paper feeder and are rotatably supported about an axis along the vertical direction, spiral grooves formed along the axial direction on the outer peripheral surfaces of the two shafts, a cable that connects the two shafts and rotates them synchronously in the same direction, two openings provided on the bottom plate of the upper paper feeder and into which the two shafts are inserted when the paper feeders are connected vertically, and pins that protrude inward from the opening edges of the two openings and engage with the spiral grooves of the two shafts when the paper feeders are connected vertically. When the paper feeders are connected vertically, the spiral grooves of the two shafts are guided by the pins and the two shafts rotate simultaneously in one direction, while when separating the vertically connected paper feeders in the vertical direction while keeping them parallel, the spiral grooves of the two shafts are guided by the pins and the two shafts rotate simultaneously in the other direction, and the rotation of only one of the two shafts is restricted by the cable.

[0008] In the present invention, it may be characterized in that the spiral grooves are two in number.

[0009] In the present invention, it may be characterized in that the connecting mechanism further includes a tension applying member that applies tension to the cable.

Effects of the Invention

[0010] According to the present invention, even when the upper paper feeder is inclined with respect to the lower paper feeder, the rotation of the left and right shafts is restricted by a cable that connects the left and right shafts so as to rotate synchronously. Therefore, the separation of the upper paper feeder from the lower paper feeder is prevented. In this way, since the upper and lower paper feeders are kept from separating, the image forming apparatus can be prevented from tipping over.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10

Embodiments for Carrying Out the Invention

[0012] Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

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

[0014] The image forming apparatus 1 includes a tandem type image forming unit 3 that forms an image on paper, and a plurality of (in this example, four) paper feeders 5 that supply paper to the image forming unit 3. The paper feeder 5 is prepared separately from the image forming apparatus 1 as an optional device. The four paper feeders 5 are stacked in the vertical direction. 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] Note that the lowermost paper feeder 5 is connected to a dedicated stand 7 equipped with casters and support means for stabilizing the installation state. By connecting the lowermost paper feeder 5 to the dedicated stand 7, the image forming apparatus 1 is easy to move and difficult to topple over. Further, the image forming unit 3 is of a tandem type and has a longer length in the depth direction (front-rear direction) than in the width direction (left-right direction). For this reason, when the image forming apparatus 1 is inclined 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 projection range of the image forming apparatus 1 on the floor surface, and it is difficult to fall in the front-rear direction. On the other hand, when the image forming apparatus 1 is inclined 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 projection range of the image forming apparatus 1 on the floor surface. For this reason, the connecting mechanism 9 of the present embodiment prevents the upper and lower paper feeders 5 from being separated and prevents toppling when inclined in the left-right direction.

[0016] Next, the connecting mechanism 9 will be described with reference to FIGS. 2 and 3A. FIG. 2 is a perspective view showing the lower paper feeder 5L, and FIG. 3A is a perspective view showing the upper paper feeder 5U. The connecting mechanism 9 includes left and right shafts 11L, 11R (see FIG. 2, hereinafter collectively referred to as shaft 11) supported by the top plate 5X of the lower paper feeder 5L, and left and right openings 13L, 13R (see FIG. 3B, hereinafter collectively referred to as opening 13) formed in the bottom plate 5Y of the upper paper feeder 5U and into which the left and right shafts 11L, 11R are respectively inserted.

[0017] First, the left and right shafts 11L, 11R will be described with reference to FIG. 2, FIGS. 4, 5A and 5B, and FIG. 6. FIG. 4 is a perspective view showing the left and right shafts 11L, 11R, FIG. 5A is a perspective view showing the shaft 11, FIG. 5B is a cross-sectional view showing the shaft 11, and FIG. 6 is a perspective view showing the tension applying member 43.

[0018] On the top plate 5X of the lower paper feeder 5L, as shown in FIG. 2, a groove 21 extending in the left - right direction is formed. As shown in FIG. 5B, the groove 21 has a wide upper portion 21a and a lower portion 21b that is narrower than the upper portion 21a. At the left and right ends of the groove 21, left and right concave portions 23 having a rounded - rectangular shape in plan view are formed.

[0019] As shown in FIGS. 5A and 5B, the shaft 11 has a coaxial cylindrical large - diameter portion 31 and a cylindrical small - diameter portion 33. On the outer peripheral surface of the large - diameter portion 31, two spiral grooves 35 extending along the axial direction of the shaft 11 are formed. The two spiral grooves 35 are formed on the diagonal line of the large - diameter portion 31. As shown in FIG. 5B, a bearing 37 is fitted into the small - diameter portion 33 of the shaft 11. The bearing 37 is supported at the upper end of the small - diameter portion 33 by a stopper 39 such as a C - ring.

[0020] The left and right shafts 11L, 11R are rotatably supported at the left and right ends of the groove 21 by bearing supports 41 that are fitted into the left and right concave portions 23. Specifically, the bearing 37 of the shaft 11 is placed on the upper surface of the upper portion 21a of the groove 21. The small - diameter portion 33 of the shaft 11 enters the lower portion 21b of the groove 21, and the large - diameter portion 31 of the shaft 11 protrudes above the top plate 5X. The bearing support 41 is fitted into the large - diameter portion 31 of the shaft 11 from above and is housed in the concave portion 23, and is fixed to the bottom surface of the concave portion 23 with screws B1. Thereby, the left and right shafts 11L, 11R are rotatably supported at the left and right ends of the groove 21 about an axis along the vertical direction.

[0021] As shown in FIG. 4, the small-diameter portions 33 of the left and right shafts 11L and 11R are connected by a cable 51. One end 51a of the cable 51 is fixed to the outer peripheral surface of the small-diameter portion 33 of the left shaft 11L with a screw B2. The cable 51 is wound around the upper part of the small-diameter portion 33 of the left shaft 11L several times along a predetermined direction (clockwise direction in this example), and then wound around the small-diameter portion 33 of the right shaft 11R several times along the same direction. Here, when the cable 51 is wound for the last time, a loop 51b is formed in the cable 51, and the formed loop 51b is fixed to the outer peripheral surface of the small-diameter portion 33 of the right shaft 11R with a screw B3. Thereafter, the cable 51 is wound around the lower part of the small-diameter portion 33 of the left shaft 11L several times along the same direction again. The other end 51c of the cable 51 is fixed to the outer peripheral surface of the small-diameter portion 33 of the left shaft 11L with a screw B4. As a result, when one shaft 11 rotates in one direction, the other shaft 11 rotates in the same direction via the cable 51.

[0022] Note that after the left and right shafts 11L and 11R are connected by this cable 51, the bearing support 41 is supported by the left and right recesses 23 of the groove 21 as described above.

[0023] As shown in FIG. 6, on the bottom surface of the groove 21 (lower part 21b), near the center in the left-right direction, two tension applying members 43 are erected side by side in the front-rear direction. The tension applying member 43 has a shaft 61 erected on the bottom surface of the groove 21, a cap 63 covering the tip of the shaft 61, and a coil spring 65 externally fitted to the shaft 61 between the cap 63 and the bottom surface. The coil spring 65 biases the cap 63 upward with respect to the bottom surface.

[0024] The cable 51 extending between the left and right shafts 11L and 11R is placed on the caps 63 of the two tension applying members 43. Thereby, the cable 51 is biased upward by the coil spring 65 via the cap 63, so that tension is applied to the cable 51 between the two shafts 11.

[0025] Next, the left and right openings 13L and 13R will be described with reference to FIGS. 3A and 3B. FIG. 3B is a view showing the opening 13 of FIG. 3A. The left and right openings 13L and 13R are circular and are formed in the bottom plate 5Y of the upper paper feeder 5U. As shown in FIG. 3B, two pins 71 protruding radially inward from the side surface along the diagonal line along the front-rear direction are fixed to the side surface of the opening 13.

[0026] Specifically, as shown in FIG. 3B, a rectangular parallelepiped-shaped recess 13a is formed on the diagonal line on the side surface of the opening 13. In this example, front and rear recesses 13a are formed on the diagonal line along the front-rear direction. The lower surface of the recess 13a opens from the lower surface of the bottom plate 5Y. The pin 71 is erected perpendicularly to one side surface of a rectangular parallelepiped-shaped base 73. The base 73 is housed in the recess 13a from below so that the pin 71 protrudes inside the opening 13, and is fixed to the bottom surface of the recess 13a by a screw B5. That is, the two pins 71 protrude radially inward of the opening 13 on the diagonal line along the front-rear direction.

[0027] The operation of connecting the upper and lower paper feeders 5U and 5L by the connecting mechanism 9 having the above configuration will be described with reference to FIGS. 7A to 9B. FIGS. 7A and 7B are side views showing the upper and lower paper feeders 5U and 5L, the shaft 11, and the pin 71 before connection. FIGS. 8A and 8B are side views showing the upper and lower paper feeders 5U and 5L, the shaft 11, and the pin 71 during connection. FIGS. 9A and 9B are side views showing the upper and lower paper feeders 5U and 5L, the shaft 11, and the pin 71 after connection.

[0028] In the initial state (the state where the paper feeder 5 is not connected), the spiral grooves 35 of the left and right shafts 11L and 11R are positioned at the same position in the circumferential direction. In this example, the upper ends of the two spiral grooves 35 of the shaft 11 are positioned on the diagonal line along the front-rear direction.

[0029] As shown in Fig. 7A, when stacking the upper and lower paper feeders 5U and 5L, the upper paper feeder 5U is held parallel to the lower paper feeder 5L, and the left and right shafts 11L and 11R of the top plate 5X of the lower paper feeder 5L are inserted into the left and right openings 13L and 13R of the bottom plate 5Y of the upper paper feeder 5U. At this time, as shown in Fig. 7B, two pins 71 are engaged with the two spiral grooves 35 of the shaft 11.

[0030] After that, as shown in Fig. 8A, while maintaining the parallelism of both, when the upper paper feeder 5U is lowered with respect to the lower paper feeder 5L, the left and right shafts 11L and 11R relatively rise within the left and right openings 13L and 13R. Then, the spiral groove 35 of the shaft 11 is guided by the pin 71, and the shaft 11 rotates simultaneously in one direction (clockwise direction in Figs. 8A and 8B, see arrow A1) around an axis along the vertical direction.

[0031] After that, as shown in Fig. 9A, while maintaining the parallelism of both, when the upper paper feeder 5U is further lowered with respect to the lower paper feeder 5L and the upper paper feeder 5U is stacked on the lower paper feeder 5L, the entire left and right shafts 11L and 11R enter the left and right openings 13L and 13R. Further, as shown in Fig. 9B, the pin 71 reaches the lowermost end of the spiral groove 35.

[0032] On the other hand, when removing the upper paper feeder 5U from the lower paper feeder 5L, while maintaining their parallelism, the upper paper feeder 5U is raised relative to the lower paper feeder 5L. Then, the spiral grooves 35 of the left and right shafts 11L and 11R are guided by the pins 71, and the left and right shafts 11L and 11R rotate simultaneously in the other direction (counterclockwise direction in FIGS. 8A and 8B). In this way, when stacking or removing the upper paper feeder 5U on the lower paper feeder 5L while maintaining the parallelism of the upper and lower paper feeders 5U and 5L, the left and right shafts 11L and 11R are always rotated in the same direction. In other words, unless the left and right shafts 11L and 11R rotate simultaneously in the same direction, the upper paper feeder 5U cannot be removed from the lower paper feeder 5L.

[0033] Next, the operation of the coupling mechanism 9 when the image forming apparatus 1 is tilted to the left will be described with reference to FIG. 10. FIG. 10 is a side view showing a state in which the upper paper feeder 5U is tilted to the left with respect to the lower paper feeder 5L.

[0034] As described above, after the upper paper feeder 5U is normally connected to the lower paper feeder 5L, when the image forming apparatus 1 is tilted to the left (see the two-dot chain line in FIG. 1), for example, the third paper feeder 5U from the top tends to tilt to the left with respect to the bottom paper feeder 5L. That is, the bottom plate 5Y of the third paper feeder 5U from the top tilts to the left with respect to the top plate 5X of the bottom paper feeder 5L, and a gap tends to be formed between the top plate 5X and the bottom plate 5Y.

[0035] Then, as shown in FIG. 10, the pin 71 of the right opening 13R attempts to move upward. Then, the spiral groove 35 of the right shaft 11R is guided by the right pin 71, and the right shaft 11R attempts to rotate in the counterclockwise direction in FIG. 10. On the other hand, since the pin 71 of the left opening 13L does not move, the left shaft 11L does not rotate. Since the left and right shafts 11L and 11R are connected by the cable 51, the rotation of the right shaft 11R is also restricted. That is, the left and right shafts 11L and 11R do not rotate simultaneously.

[0036] In this way, even if the upper paper feeder 5U is inclined with respect to the lower paper feeder 5L, since the left and right shafts 11L and 11R do not rotate simultaneously, the upper and lower paper feeders 5U and 5L cannot be separated. Since the upper and lower paper feeders 5U and 5L cannot be separated in this way, the image forming apparatus 1 is prevented from tipping over.

[0037] As described above, according to the present invention, even if the image forming apparatus 1 is inclined, the upper and lower paper feeders 5U and 5L are automatically maintained so as not to be separable by the connecting mechanism 9, so that the image forming apparatus 1 can be prevented from tipping over. Specifically, even when the upper paper feeder 5U is inclined with respect to the lower paper feeder 5L, the rotation of the left and right shafts 11L and 11R is restricted by the cable 51 that connects the left and right shafts 11L and 11R so as to rotate synchronously, so that the upper paper feeder 5U is prevented from separating from the lower paper feeder 5L.

[0038] On the other hand, when the upper paper feeder 5U is lifted while remaining parallel to the lower paper feeder 5L and the left and right shafts 11L and 11R simultaneously come out of the left and right openings 13L and 13R, the left and right shafts 11L and 11R rotate simultaneously, so that the upper paper feeder 5U can be separated from the lower paper feeder 5L.

[0039] In addition, since the two spiral grooves 35 are formed diagonally, the rotation of the shaft 11 is stabilized when the pin 71 moves in the vertical direction. In the initial state, the left and right shafts 11L and 11R may be positioned using a spring or the like so that the upper end of the spiral groove 35 and the pin 71 are in the same position in the circumferential direction.

[0040] Furthermore, since tension is applied to the cable 51 by the tension applying member 43, rotation can be transmitted more accurately and quickly from one shaft 11 to the other shaft 11.

[0041] In the present embodiment, as described above, the coupling mechanism 9 for the image forming apparatus 1 having a structure that is likely to tilt in the left - right direction has been described. That is, the two shafts 11 of the coupling mechanism 9 are arranged so as to be separated from each other in the left - right direction. However, for example, in the case of an image forming apparatus 1 having a structure that is likely to tilt in the front - rear direction, the two shafts 11 of the coupling mechanism 9 may be arranged so as to be separated from each other in the front - rear direction, and both shafts 11 may be connected by a cable 51.

[0042] Also, although the left and right shafts 11L and 11R are connected by a cable 51, sprockets may be fixed to the left and right shafts 11L and 11R, and both sprockets may be connected by a timing belt.

[0043] Although the present invention has been described with respect to specific embodiments, the present invention is not limited to the above embodiments. Without departing from the scope and gist of the present invention, the above embodiments may be variously changed, substituted, and modified, and the claims include all embodiments that can be included within the scope of the technical idea.

Explanation of Reference Numerals

[0044] 1 Image forming apparatus 3 Image forming unit 5(5U, 5L) Paper feeder 9 Coupling mechanism 11(11L, 11R) Shaft 13(13L, 13R) Opening 35 Spiral groove 43 Tension applying member 51 Cable 71 Pin

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, wherein the image forming unit is placed on the plurality of paper feeders that are vertically connected by a connecting mechanism, The connecting mechanism is, Two shafts that are arranged at a predetermined interval on the top plate of the lower paper feeder and are rotatably supported about an axis along the vertical direction, Spiral grooves formed along the axial direction on the outer peripheral surfaces of the two shafts, A cable that connects the two shafts and rotates them synchronously in the same direction, Two openings provided on the bottom plate of the upper paper feeder into which the two shafts are inserted when the paper feeders are vertically connected, Pins that project inward from the edges of the two openings and engage with the spiral grooves of the two shafts when the paper feeders are vertically connected, When the paper feeders are vertically connected, the spiral grooves of the two shafts are guided by the pins and the two shafts rotate simultaneously in one direction. On the other hand, when the vertically connected paper feeders are separated vertically while remaining parallel, the spiral grooves of the two shafts are guided by the pins and the two shafts rotate simultaneously in the other direction, An image forming apparatus, characterized in that the rotation of only one of the two shafts is restricted by the cable.

2. The image forming apparatus according to claim 1, wherein the spiral grooves are two in number.

3. The connecting mechanism is, The image forming apparatus according to claim 1, further comprising a tension applying member that applies tension to the cable.

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