Image forming apparatus

Abstract

To provide an image forming apparatus that allows sheet feeding only when a paper-feeding cassette is correctly attached to a cassette attachment part.SOLUTION: An image forming apparatus comprises a sensor 61 switchable between a cassette detection state where a paper-feeding cassette is attached and a cassette non-detection state where no paper-feeding cassette thereof is attached. The paper-feeding cassette comprises a detection piece 41 for switching the sensor 61, a presser piece 43 integrally provided with the detection piece 41, and a lock reception part for movably supporting the presser piece 43. A cassette attachment part comprises a lock member 55 engaging with the lock reception part, when the paper-feeding cassette is attached to the cassette attachment part. When the paper-feeding cassette is attached to the cassette attachment part, the detection piece 41 switches the sensor 61 from the cassette non-detection state to the cassette detection state, and the lock member 55 is engaged with the lock reception part when the presser piece 43 interferes with the lock member 55.SELECTED DRAWING: Figure 10A

Description

Technical Field

[0001] The present invention relates to an image forming apparatus including a detachable paper feed cassette. Background Art

[0002] Image forming apparatuses such as multifunction peripherals and printers include a detachable paper feed cassette. When the paper feed cassette is mounted in a cassette mounting portion of an apparatus main body, sheets can be fed toward a conveyance path by a paper feed mechanism provided in the cassette mounting portion.

[0003] If the paper feed cassette is not properly mounted in the cassette mounting portion, problems occur such as stopping of the paper feeding operation or occurrence of paper jam. Accordingly, as disclosed in Patent Document 1, an image forming apparatus may be provided with a lock mechanism that locks the paper feed cassette mounted to the apparatus main body. The lock mechanism includes a lock piece rotatably provided on a support unit of the apparatus main body, and a protruding portion provided on the paper feed cassette. As the paper feed cassette is mounted to the apparatus main body, the protruding portion engages with the lock piece, so that the paper feed cassette is locked to the apparatus main body.

[0004] Further, such an image forming apparatus includes a sensor that is switched between a cassette detected state where the paper feed cassette is mounted in the cassette mounting portion and a cassette non-detected state where no paper feed cassette is mounted. When the sensor is switched from the cassette non-detected state to the cassette detected state, feeding of sheets from the paper feed cassette is started. Prior Art Literature Patent Literature

[0005] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2016-101994 Summary of the Invention Problem to be Solved by the Invention

[0006] However, in the image forming apparatus described in Patent Document 1, the sensor may switch from a cassette non-detection state to a cassette detection state even when the locking piece and the projection are not securely engaged, that is, when the paper feed cassette is not properly installed in the cassette mounting section. In such a state, when the sensor switches from a cassette non-detection state to a cassette detection state and the feeding of sheets from the paper feed cassette begins, problems such as the cessation of the paper feeding operation or paper jams may occur.

[0007] Therefore, the present invention aims to provide an image forming apparatus that can feed sheets only when the paper feed cassette is correctly installed in the cassette mounting section, taking the above circumstances into consideration. [Means for solving the problem]

[0008] To achieve the above objective, the image forming apparatus of the present invention comprises a paper feed cassette in which sheets are contained, a cassette mounting section in which the paper feed cassette is mounted, and a sensor provided in the cassette mounting section that switches between a cassette detection state in which the paper feed cassette is mounted and a cassette non-detection state in which the paper feed cassette is not mounted. The paper feed cassette has a detection piece that switches the sensor between the cassette detection state and the cassette non-detection state, a retaining piece provided integrally with the detection piece, and a lock receiving section that movably supports the retaining piece. The cassette mounting section has a locking member that is pivotably supported and engages with the lock receiving section when the paper feed cassette is mounted in the cassette mounting section. When the paper feed cassette is mounted in the cassette mounting section, the detection piece switches the sensor from the cassette non-detection state to the cassette detection state, and the retaining piece interferes with the locking member, causing the locking member to engage with the lock receiving section.

[0009] In the image forming apparatus of the present invention, the locking member is provided to swing upward and then downward to engage with the locking receiving portion, the pressing piece is supported by the locking receiving portion so as to be movable in the vertical direction, and the cassette mounting portion has guide ribs that guide the detection piece and the pressing piece in the vertical direction as the paper feed cassette is mounted to the cassette mounting portion, and the guide ribs may be characterized in that, when the paper feed cassette is mounted to the cassette mounting portion, the detection piece is guided to the detection position of the sensor and the pressing piece is brought into contact with the locking member from above to guide the locking member to engage with the locking receiving portion.

[0010] In the image forming apparatus of the present invention, the detection piece has an arm piece connected to the pressing piece, the guide rib has a pair of rib pieces spaced apart in a width direction intersecting the mounting direction, and the arm piece is guided along the pair of rib pieces when the paper feed cassette is mounted in the cassette mounting section. [Effects of the Invention]

[0011] According to the present invention, when a paper feed cassette is installed in the cassette mounting section, the detection piece switches the sensor, and at the same time, the retaining piece interferes with the locking member, causing the locking member to engage with the locking receiver. As a result, sheets can only be fed out when the paper feed cassette is correctly installed in the cassette mounting section. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view showing the internal structure of an image forming apparatus according to one embodiment of the present invention. [Figure 2] This is a perspective view showing a paper feed cassette and a cassette mounting section in an image forming apparatus according to one embodiment of the present invention. [Figure 3] This is a perspective view showing the locking mechanism on the paper feed cassette side in an image forming apparatus according to one embodiment of the present invention. [Figure 4]This is a perspective view showing the locking mechanism on the cassette mounting section side of an image forming apparatus according to one embodiment of the present invention. [Figure 5] This is a side view showing the sheet feeding section in an image forming apparatus according to one embodiment of the present invention. [Figure 6A] This is a side view showing the link member and sensor in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (first stage). [Figure 6B] This is a side view showing the lock receiving portion and locking member in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (first stage). [Figure 7A] This is a side view showing the link member and sensor in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (second stage). [Figure 7B] This is a side view showing the lock receiving portion and locking member in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (second stage). [Figure 8A] This is a side view showing the link member and sensor in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (third stage). [Figure 8B] This is a side view showing the lock receiving portion and locking member in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (third stage). [Figure 9A] This is a side view showing the link member and sensor in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (fourth stage). [Figure 9B] This is a side view showing the lock receiving portion and locking member in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (fourth stage). [Figure 10A] This is a side view showing the link member and sensor in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (fifth stage). [Figure 10B] This is a side view showing the lock receiving portion and locking member in an image forming apparatus according to one embodiment of the present invention when the paper feed cassette is installed (fifth stage). MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[0014] First, the overall configuration of the image forming apparatus 1 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a side view schematically showing the internal structure of the image forming apparatus 1. In the following description, the left side of the drawing sheet of FIG. 1 is taken as the front side (front side) of the image forming apparatus 1. Fr, Rr, L, and R in each drawing indicate the front side, rear side, left side, and right side of the image forming apparatus, respectively.

[0015] An apparatus main body 3 of the image forming apparatus 1 includes a rear cover 5 that opens and closes an opening 3a provided on a rear surface, and a conveyance unit 7 arranged inside the rear cover 5. The rear cover 5 and the conveyance unit 7 are each supported by the apparatus main body 3 so as to be rotatable about their lower end portions. A main conveyance path 9 extending upward from below is formed between the apparatus main body 3 and the conveyance unit 7. A substantially C-shaped reverse conveyance path 11 as viewed in a side view is formed between the conveyance unit 7 and the rear cover 5. Rotating the rear cover 5 downward opens the reverse conveyance path 11, and rotating the conveyance unit 7 downward together with the rear cover 5 opens the main conveyance path 9.

[0016] A sheet is conveyed along the main conveyance path 9 in a conveyance direction extending upward from below. The reverse conveyance path 11 branches at a branch point B on the downstream side in the conveyance direction of the main conveyance path 9, and merges at a confluence J on the upstream side of the main conveyance path 9. Further, a manual feed path 13 is formed in the apparatus main body 3. The manual feed path 13 is formed substantially horizontally from a manual feed port 3b formed on a front surface of the apparatus main body 3 toward the confluence J, and merges with the main conveyance path 9 at the confluence J.

[0017] The main body of the device 3 is provided with a cassette storage section 15 below the manual feed path 13. The cassette storage section 15 has an opening on the front of the main body of the device 3. The paper feed cassette 17 is removably housed in the cassette storage section 15. The cassette storage section 15 is equipped with a cassette mounting section 19 into which the paper feed cassette 17 is mounted, and a paper feeding section 21 that feeds sheets from the paper feed cassette 17 mounted in the cassette mounting section 19 to the main transport path 9. The paper feed cassette 17 is inserted into the cassette storage section 15 through the opening and mounted in the cassette mounting section 19. The direction in which the paper feed cassette 17 is inserted into the cassette storage section 15 (from front to back) is called the mounting direction X. The paper feed cassette 17, cassette mounting section 19, and paper feeding section 21 will be described later.

[0018] The main body of the device 3 is provided with an image forming unit 23 above the manual feed path 13. The image forming unit 23 forms an image on the sheet, for example, using an electrophotographic method. Sheets fed from the paper feed cassette 17, or sheets transported along the manual feed path 13, are transported along the main transport path 9, and an image is formed on the sheet in the image forming unit 23.

[0019] Next, the paper feed cassette 17, the cassette mounting section 19, and the paper feeding section 21 will be described with reference to Figures 2 to 5. Figure 2 is a perspective view showing the paper feed cassette 17 and the cassette mounting section 19, Figure 3 is a perspective view showing the locking mechanism on the paper feed cassette side, Figure 4 is a perspective view showing the locking mechanism on the cassette mounting section side, and Figure 5 is a side view showing the paper feeding section 21.

[0020] The paper feed cassette 17 and the cassette mounting section 19 are equipped with a locking mechanism that secures the cassette mounting section 19 and the paper feed cassette 17 when the paper feed cassette 17 is correctly mounted in the cassette mounting section 19. Furthermore, the cassette mounting section 19 is equipped with a sensor 61 that can switch between a cassette detection state in which the paper feed cassette 17 is mounted and a cassette non-detection state in which the paper feed cassette is not mounted.

[0021] First, let's describe the paper feed cassette 17. As shown in Figure 2, the paper feed cassette 17 is formed in the shape of a shallow box with an open top. The paper feed cassette 17 is equipped with a sheet loading plate 31 and a lift plate 32 (see Figure 1, not shown in Figure 2). The sheet loading plate 31 is positioned on the bottom plate of the paper feed cassette 17 and is rotatable upward toward the downstream (rear) side in the loading direction X. The lift plate 32 is positioned between the sheet loading plate 31 and the bottom plate and is rotatable vertically about its axis of rotation. When the lift plate 32 rotates upward, the sheet loading plate 31 tilts upward toward the downstream side in the loading direction X.

[0022] As shown in Figure 3, the locking mechanism on the paper feed cassette side comprises a pair of locking receivers 33 and a link member 35 supported by the pair of locking receivers 33. The locking mechanism is provided on the downstream side plate (rear side plate) 17a of the paper feed cassette 17 in the mounting direction X.

[0023] A pair of locking receivers 33 are provided on the outer surface of the rear side plate 17a at a predetermined distance from the center in the width direction (left-right direction) intersecting the mounting direction X. Each locking receiver 33 protrudes toward the downstream side (rear, toward the cassette mounting section 19) in the mounting direction X. Each locking receiver 33 has a pair of side plates 33a facing each other in the width direction, a bottom plate 33b, a top plate 33c, and a rear plate 33d, forming a recess 33x surrounded by each plate.

[0024] Each side plate 33a has an L-shape when viewed from the front or rear direction, and has a vertical portion that runs vertically and a protruding portion that extends from the lower end of the vertical portion. A slit 33y of a predetermined length running vertically is formed in the vertical portion of the side plate 33a on the inside (center side) of each lock receiving portion 33. The rear plate 33d is inclined downward toward the downstream side in the mounting direction X.

[0025] The link member 35 is a V-shaped member when viewed from the front or rear direction, and has a detection piece 41, a pair of retaining pieces 43, and a pair of arm pieces 45 provided between the detection piece 41 and the pair of retaining pieces 43. The detection piece 41 is a rectangular plate-shaped portion with thickness along the width direction and extending in the vertical direction and the mounting direction X. Each retaining piece 43 is a rectangular plate-shaped portion with thickness along the vertical direction and extending in the width direction and the mounting direction X. The pair of arm pieces 45 extend diagonally upward in opposite directions from the downstream (front) side edge of the detection piece 41 in the mounting direction X, and are plate-shaped portions with thickness along the mounting direction X and extending in the width direction and vertical direction. The retaining pieces 43 are provided at the tip of each arm piece 45 so as to protrude in the mounting direction X.

[0026] The link member 35 is supported on the rear plate 17a so as to be movable in the vertical direction, with the detection piece 41 and the retaining piece 43 facing downstream (rear) in the mounting direction X, and the detection piece 41 being in the center in the width direction. In detail, a pair of arm pieces 45 pass through a slit 33y formed in the side plate 33a of the pair of lock receiving parts 33, and the pair of retaining pieces 43 are housed in the recess 33x of the pair of lock receiving parts 33. As the pair of arm pieces 45 are guided vertically along the slit 33y, the detection piece 41 and the pair of retaining pieces 43 move vertically. The pair of retaining pieces 43 move between the side plates 33a of the pair of lock receiving parts 33.

[0027] Furthermore, a coil spring 47 is positioned between the top plate 33c of the pair of lock receiving portions 33 and the pair of retaining pieces 43. The coil spring 47 biases the pair of retaining pieces 43 downward relative to the top plate 33c. In other words, the coil spring 47 biases the link member 35 downward until each arm piece 45 contacts the lower end of the slit 33y.

[0028] Next, the cassette mounting section 19 will be described. The cassette mounting section 19 is located at the downstream end (rear) of the cassette storage section 15 in the mounting direction X. As shown in Figure 2, a recess 51 is formed in the center of the width direction of the cassette mounting section 19, which can accommodate the separation roller 85 (see Figure 5) supported by the holder 87. Guide sections 53 are formed on both sides of the recess 51 to guide the sheet to the main transport path 9.

[0029] As shown in Figure 4, the locking mechanism on the cassette mounting side has a pair of locking members 55 that correspond to a pair of locking receiving parts 33 of the locking mechanism on the paper feed cassette side. The locking members 55 are supported so as to protrude upstream (front) in the mounting direction X and are supported so as to be able to swing in the vertical direction. A downward-facing locking projection 57 is provided at the tip of the locking member 55. The locking projection 57 has a triangular shape when viewed from the left and right directions and has an inclined front surface 57a and an inclined rear surface 57b. Each locking member 55 is biased to rotate downward by a coil spring 59.

[0030] Furthermore, the cassette mounting section 19 is equipped with a sensor 61 that can be switched between a cassette detection state in which the paper feed cassette 17 is mounted and a cassette non-detection state in which the paper feed cassette is not mounted, as described above. The sensor 61 is supported by a sensor holder 63 and is positioned in the center in the width direction, below the pair of locking members 55. The sensor 61 is, for example, an optical sensor having a light-emitting section and a light-receiving section. The light-emitting section and the light-receiving section are arranged with a predetermined distance between them in the width direction. The sensor 61 is switched to a cassette non-detection state in which the paper feed cassette 17 is not mounted when an optical path P is formed between the light-emitting section and the light-receiving section, and is switched to a cassette detection state in which the paper feed cassette 17 is mounted when the optical path P is blocked. Thus, the optical path P indicates the detection position of the sensor 61 in this invention.

[0031] The sensor holder 63 has a bottom plate on which the sensor 61 is placed, and a front plate provided on the upstream side (front side) of the sensor 61 in the mounting direction X. A cross-shaped slit 63a is formed in the front plate. The slit 63a is aligned with the optical path P of the sensor 61 and along the mounting direction X.

[0032] A rib 71 is provided on the front side (upstream side in the mounting direction X) of the sensor 61 (front plate of the sensor holder 63). The rib 71 consists of a pair of rib pieces 73 arranged at a predetermined interval in the width direction. Each rib piece 73 has a trapezoidal shape when viewed from the left-right direction and has an upper edge 73a and front and rear edges 73b and 73c. ​​The corners between the upper edge 73a and the front and rear edges 73b and 73c are rounded. The space between the pair of rib pieces 73 and the optical path P of the sensor 61 are aligned along the mounting direction X.

[0033] Next, the paper feeding section 21 will be described with reference to Figure 5. The paper feeding section 21 is located above the cassette mounting section 19 and includes a feed roller 81 and a paper feeding roller 83 located downstream of the feed roller 81 in the mounting direction X. The paper feeding roller 83 is in contact with a separation roller 85 supported by a recess 51 in the cassette mounting section 19, forming a separation nip N between the two rollers.

[0034] In the image forming apparatus 1 having the above configuration, the operation of attaching the paper feed cassette 17 to the cassette mounting section 19 and the paper feeding operation from the paper feed cassette 17 will be explained with reference to Figures 6A to 10B. Figures 6A to 10A are side views showing the link member 35 and the sensor 61, and Figures 6B to 10B are side views showing the lock receiving section 33 and the lock member 55. As described above, the paper feed cassette 17 is inserted into the cassette housing section 15 through the opening of the apparatus body 2 along the mounting direction X.

[0035] As the paper feed cassette 17 approaches the cassette mounting section 19 (first stage), as shown in Figure 6A, first, the detection piece 41 of the link member 35 enters between the pair of rib pieces 73 of the rib 71, and the pair of arm pieces 45 of the link member 35 contact the front edge 73b of the pair of rib pieces 73 of the rib 71. At the same time, as shown in Figure 6B, the rear plate 33d of the pair of lock receiving sections 33 contacts the front surface 57a of the projection 57 of the pair of lock members 55.

[0036] As the paper feed cassette 17 approaches the cassette mounting section 19 (second stage), as shown in Figure 7A, the pair of arm pieces 45 rise along the front edge 73b of the pair of rib pieces 73, and the link member 35 rises. The detection piece 41 rises and enters the slit 63a of the front plate of the holder 63 from between the pair of rib pieces 73. At this time, the pair of retaining pieces 43 move upward between the pair of side plates 33a of the pair of lock receiving sections 33, against the biasing force of the coil spring 47. Simultaneously, as shown in Figure 7B, the rear plate 33d of the pair of lock receiving sections 33 moves along the front surface 57a of the projection 57 of the pair of lock members 55, and the pair of lock members 55 begin to rotate upward against the biasing force of the coil spring 59. Here, as shown in Figure 7A, the pair of retaining pieces 43 are raised above the top of the pair of lock members 55.

[0037] As the paper feed cassette 17 approaches the cassette mounting section 19 (third stage), as shown in Figure 8A, the pair of arm pieces 45 move from the front edge 73b of the pair of rib pieces 73 to the upper edge 73a and move along the upper edge 73a. That is, the link member 35 moves along the mounting direction X while remaining raised. The detection piece 41 further enters the slit 63a of the front plate of the holder 63. At the same time, as shown in Figure 8B, the rear plate 33d of the pair of lock receiving sections 33 reaches the lower end of the projection 57 of the pair of lock members 55, and the pair of lock members 55 rotates to its uppermost position. At this point, as shown in Figure 8A, the pair of retaining pieces 43 contact the top of the pair of lock members 55 from above.

[0038] As the paper feed cassette 17 approaches the cassette mounting section 19 (fourth stage), as shown in Figure 9A, the pair of arm pieces 45 move from the upper edge 73a to the rear edge 73c of the pair of rib pieces 73, and move along the rear edge 73c. ​​In other words, the link member 35 begins to descend due to its own weight and the biasing force of the coil spring 47. At this time, the arm pieces 45 descend while pressing against the rear edge 73c, so the link member 35 descends steadily. The detection piece 41 begins to enter between the light-emitting part and the light-receiving part of the sensor 61 through the slit 63a of the front plate of the holder 63. At the same time, as shown in Figure 9B, the rear plate 33d of the pair of lock receiving parts 33 passes over the lower end of the projection 57 of the pair of lock members 55. As a result, the projection 57 of the lock member 55 begins to enter the recess 33x of the lock receiving part 33. In other words, the pair of lock members 55 begin to rotate downward. Here, the pair of retaining pieces 43 descend together with the detection piece 41, which has begun to descend, while contacting the uppermost part of the pair of locking members 55.

[0039] As the paper feed cassette 17 approaches the cassette mounting section 19 (fifth stage), as shown in Figure 10A, the pair of arm pieces 45 move partway along the trailing edge 73c of the pair of rib pieces 73, and the link member 35 descends further. The detection piece 41 descends between the light-emitting and light-receiving sections of the sensor 61 and enters the optical path P of the sensor 61. This switches the sensor 61 from a cassette non-detection state to a cassette detection state. Simultaneously, as shown in Figure 10B, the pair of locking members 55 rotate downward, and the projections 57 of the pair of locking members 55 enter the recesses 33x of the pair of locking receiving sections 33. In other words, the locking members 55 engage with the locking receiving sections 33, and the paper feed cassette 17 is mounted on the cassette mounting section 19. The pair of retaining pieces 43 are biased by the coil spring 47 and contact the pair of locking members 55. Furthermore, the downward movement of the link member 35 is stopped when the pair of retaining pieces 43 come into contact with the pair of locking members 55 in this manner.

[0040] When the sensor 61 switches from a cassette non-detection state to a cassette detection state, sheet feeding begins. That is, the feed roller 81 of the paper feeding unit 21 rotates and feeds out the top sheet of the sheets placed on the sheet stacking plate 31 of the paper feeding cassette 17. The fed sheet is separated by the separation nip and transported to the main transport path 9.

[0041] When removing the paper feed cassette 17 from the cassette mounting section 19, the paper feed cassette 17 is pulled out in the opposite direction to the mounting direction X. As a result, the rear plate 33d of each lock receiving section 33 of the paper feed cassette moves along the rear surface 57b of the projection 57 of each locking member 55, causing each locking member 55 to rotate upward, the projection 57 to move away from the recess 33x, and the engagement between the lock receiving section 33 and the locking member 55 is released.

[0042] As is clear from the above description, according to the present invention, a detection piece 41 for switching the sensor 61 and a retaining piece 43 for engaging the locking member 55 with the locking receiving portion 33 are provided integrally. Therefore, when the paper feed cassette 17 is mounted in the cassette mounting portion 19, the detection piece 41 switches the sensor 61 from a non-cassette detection state to a cassette detection state, and at the same time, the retaining piece 43 interferes with the locking member 55, causing the locking member 55 to engage with the locking receiving portion 33. In other words, as the sensor 61 switches from a non-cassette detection state to a cassette detection state, the pair of locking receiving portions 33 and the pair of locking members 55 engage, and the paper feed cassette 17 is mounted in the cassette mounting portion 19.

[0043] In other words, if the locking member 55 is not properly engaged with the locking receiver 33, the detection piece 41 will not reach the optical path P of the sensor, and the sheet feeding operation cannot be started. For example, as shown in Figure 9B, if the locking member 55 is not fully engaged with the locking receiver 33, as shown in Figure 9A, the optical path P of the sensor 61 is not blocked by the detection piece 41, the sensor 61 will not switch from a cassette non-detection state to a cassette detection state, and the sheet feeding will not start. Thus, sheet feeding is only possible when the paper feed cassette 17 is properly installed in the paper feed cassette mounting section 18.

[0044] Furthermore, when the paper feed cassette 17 is mounted in the cassette mounting section 19, the locking member 55 rotates upward and then downward to engage with the locking receiver 33. In accordance with this movement of the locking member 55, the retaining piece 43, i.e., the linking member 35, is guided by the guide rib 71 to move upward, then move along the mounting direction X, and then move downward. In this way, the retaining piece 43 moves above the locking member 55, so that when the locking member 55 engages with the locking receiver 33, the retaining piece 43 can be reliably brought into contact with the locking member 55 from above.

[0045] Furthermore, as the link member 35 is guided along the guide rib 71, the pair of arm pieces 45 are guided along the front edge 73b, upper edge 73a, and rear edge 73c of the pair of rib pieces 73. This reduces the contact area between the pair of arm pieces 45 and the pair of rib pieces 73, thereby reducing friction between them. Consequently, the link member 35 can be guided stably.

[0046] Furthermore, as the link member 35 is guided along the guide rib 71, a pair of arm pieces 45 of the link member 35 move vertically along the slits 33y of the pair of lock receiving portions 33. Since the arm pieces 45 have a thickness along the mounting direction X and are formed in a plate shape that extends in the width direction and vertical direction, they are stably guided vertically along the slits 33y. As a result, the link member 35 can be moved vertically stably without tilting in the mounting direction X or the opposite direction.

[0047] Furthermore, the above-described embodiments of the present invention describe preferred embodiments of the image forming apparatus and paper feed cassette according to the present invention, and therefore may include various technically preferred limitations. However, the technical scope of the present invention is not limited to these embodiments unless otherwise specified. [Explanation of symbols]

[0048] 1. Image forming apparatus 17 Paper feed cassette 19 Cassette slot 33 Lock receiving part 41 detection pieces 43 Pressing piece 45 Arm Pieces 55 Locking member 71 Guide Ribs 73 Rib pieces

Claims

1. A paper feed cassette in which the sheets are stored, The cassette mounting section into which the aforementioned paper feed cassette is installed, The cassette mounting section is provided with a sensor that can switch between a cassette detection state in which the paper feed cassette is installed and a cassette non-detection state in which the paper feed cassette is not installed. The aforementioned paper feed cassette is The sensor includes a detection piece that switches between the cassette detection state and the cassette non-detection state, A pressing piece provided integrally with the detection piece, The lock receiving portion has a locking piece that is movably supported, The aforementioned cassette mounting section is It has a locking member that is pivotably supported and engages with the locking receiver when the paper feed cassette is mounted in the cassette mounting section, An image forming apparatus characterized in that, when the paper feed cassette is mounted in the cassette mounting section, the detection piece switches the sensor from a cassette non-detection state to a cassette detection state, and the retaining piece interferes with the locking member to engage the locking member with the locking receiver.

2. The locking member is provided to swing upward and then downward to engage with the locking receiver. The retaining piece is supported by the lock receiving portion so as to be movable in the vertical direction. The cassette mounting section has guide ribs that guide the detection piece and the retaining piece in the vertical direction when the paper feed cassette is mounted to the cassette mounting section. The image forming apparatus according to claim 1, characterized in that the guide rib guides the detection piece to the detection position of the sensor when the paper feed cassette is mounted in the cassette mounting section, and also guides the pressing piece to contact the locking member from above so that the locking member engages with the locking receiver.

3. The detection piece has an arm piece that connects to the pressing piece, The guide rib has a pair of rib pieces that are spaced apart in the width direction intersecting the mounting direction, The image forming apparatus according to claim 2, characterized in that when the paper feed cassette is mounted in the cassette mounting section, the arm piece is guided along the pair of rib pieces.

Images