Image forming apparatus

Abstract

The present invention provides an image forming apparatus that allows for easy maintenance work in a configuration that restricts the swinging of the second cover relative to the first cover when the first cover is opened. [Solution] In the image forming apparatus 1, the first cover 10 has a first engaging portion 11. The second cover 20 has a second engaging portion 21. The apparatus body 90 has a contact portion 91. When the second cover 20 swings from the second closed position to the second open position while the first cover 10 is in the first closed position, the second engaging portion 21, which has moved to a non-engagement position by contacting the contact portion 91, does not engage with the first engaging portion 11 and allows the second cover 20 to swing relative to the first cover 10. When the first cover 10 swings from the first closed position to the first open position while the second cover 20 is in the second closed position, the second engaging portion 21, which has moved to an engagement position away from the contact portion 91, engages with the first engaging portion 11 and restricts the swing of the second cover 20 relative to the first cover 10.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Patent Document 1 discloses an example of a conventional image forming apparatus. In this image forming apparatus, a cartridge door corresponding to a first door is supported by the exterior of the apparatus main body so as to be openable and closable. A feed tray door corresponding to a second door is supported by the cartridge door so as to be openable and closable. The cartridge door has a lock mechanism.

[0003] When the cartridge door is in a closed state, the rotary cam of the lock mechanism abuts against the exterior, and the tip end of the stopper of the lock mechanism is disengaged from the tray door opening of the feed tray door, so that the feed tray door can be opened.

[0004] When the cartridge door starts to open, the rotary cam of the lock mechanism separates from the exterior, and the tip end of the stopper of the lock mechanism engages with the tray door opening of the feed tray door, so that the swing of the feed tray door relative to the cartridge door is restricted.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0006] However, in the conventional image forming apparatus described above, the cartridge door, which is closer to the exterior than the feed tray door and is difficult for a user to reach, is provided with a stopper and a mechanism that interlocks the stopper with the opening and closing of the cartridge door. As a result, this image forming apparatus has a problem that when damage or malfunction of the stopper or the like occurs, it is difficult to easily perform maintenance work such as component replacement and repair.

[0007] The present invention aims to provide an image forming apparatus that allows for easy maintenance work, in which the oscillation of the second cover relative to the first cover is restricted when the first cover is opened. [Means for solving the problem]

[0008] The present invention provides an image forming apparatus having a cartridge for storing toner, and an image forming unit for forming an image on a sheet, The apparatus body housing the image forming unit, the apparatus body having a first opening formed therein for attaching and detaching the cartridge, A first cover is movably supported on the main body of the apparatus and moves between a first closed position that closes the first opening and a first open position that opens the first opening, the first cover having a second opening formed therein for allowing a sheet being conveyed toward the image forming section to pass through when in the first closed position, A second cover that is pivotably supported by the first cover and pivots to a second closed position that closes the second opening and a second open position that opens the second opening, the second cover being capable of supporting a sheet before it is conveyed toward the image forming unit when in the second open position, An image forming apparatus comprising, The first cover has a first engaging portion that is immovably provided to the first cover and is capable of engaging with the second cover in the second closed position. The second cover has a second engaging portion that is movable between an engageable position in which it can engage with the first engaging portion and an inengagement position in which it cannot engage with the first engaging portion. The device body has a contact portion that moves the second engaging portion to the non-engagement position by contacting the second engaging portion, and moves the second engaging portion to the engagement position by moving it away from the second engaging portion. When the first cover is in the first closed position, and the second cover swings from the second closed position to the second open position, the second engaging portion, which is in contact with the contact portion and in the non-engagement position, does not engage with the first engaging portion, and allows the swing of the second cover relative to the first cover. When the first cover swings from the first closed position to the first open position while the second cover is in the second closed position, the second engaging portion, which is located at the engageable position away from the contact portion, is configured to engage with the first engaging portion to restrict the swinging of the second cover relative to the first cover.

[0009] In the image forming apparatus of the present invention, the first engaging portion of the first cover is provided immovably on the first cover and has a simple configuration that allows it to engage with the second cover in the second closed position, thus making malfunctions less likely to occur.

[0010] The contact portion of the device body has a simple configuration that allows it to contact the second engaging portion, making malfunctions less likely.

[0011] Furthermore, the second engaging portion of the second cover, which is located further away from the main body of the device than the first cover and is more easily accessible to the user, is configured to be movable between an engaging position and an unengaging position, allowing for easy replacement of parts, repairs, etc., in the event of damage or malfunction of the second engaging portion.

[0012] Therefore, the image forming apparatus of the present invention, with its configuration that restricts the swinging of the second cover relative to the first cover when the first cover is opened, allows for easy maintenance work. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a perspective view of the image forming apparatus of Embodiment 1, showing the state in which the first cover is in the first closed position and the second cover is in the second closed position. [Figure 2] Figure 2 is a partial perspective view of the image forming apparatus of Embodiment 1, showing the state in which the first cover is in the first open position and the second cover is in the second closed position. [Figure 3] Figure 3 is a partial perspective view of the image forming apparatus of Embodiment 1, showing the state in which the first cover is in the first closed position and the second cover is in the second open position. [Figure 4] Figure 4 is a schematic partial cross-sectional view of the image forming apparatus of Embodiment 1, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the first cover is in the first closed position and the second cover is in the second closed position. [Figure 5] Figure 5 is a schematic partial cross-sectional view similar to Figure 4, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the first cover is in the first closed position and the second cover is swinging toward the second open position. [Figure 6] Figure 6 is a schematic partial cross-sectional view similar to Figure 4, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the second cover is in the second closed position and the first cover is swinging toward the first open position. [Figure 7] Figure 7 relates to the image forming apparatus of Embodiment 2 and is a schematic partial cross-sectional view similar to Figure 4, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the first cover is in the first closed position and the second cover is in the second closed position. [Figure 8] Figure 8 is a schematic partial cross-sectional view similar to Figure 7, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the first cover is in the first closed position and the second cover is swinging toward the second open position. [Figure 9] Figure 9 is a schematic partial cross-sectional view similar to Figure 7, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the second cover is in the second closed position and the first cover is swinging toward the first open position. [Figure 10] Figure 10 is a schematic partial cross-sectional view similar to Figure 4 relating to the image forming apparatus of Embodiment 3, illustrating the relative relationship between the first engaging portion, the second engaging portion, and the contact portion when the first cover is in the first closed position and the second cover is in the second closed position. [Figure 11] Figure 11 is a schematic partial cross-sectional view showing section AA of Figure 10. [Figure 12] Figs. 12(a) to (c) are schematic partial cross-sectional views similar to Fig. 11, and are diagrams for explaining the relative relationship of the first engaging portion, the second engaging portion, and the abutting portion in a state where the first cover is at the first closed position and the second cover swings toward the second open position. [Figure 13] Figs. 13(a) to (c) are schematic partial cross-sectional views similar to Fig. 11, and are diagrams for explaining the relative relationship of the first engaging portion, the second engaging portion, and the abutting portion in a state where the second cover is at the second closed position and the first cover swings toward the first open position. [Mode for Carrying Out the Invention]

[0014] Hereinafter, Examples 1 to 3 that embody the present invention will be described with reference to the drawings.

[0015] (Example 1) As shown in Fig. 1, an image forming apparatus 1 of Example 1 is an example of a specific aspect of the image forming apparatus of the present invention. In Fig. 1, the side where the first cover 10 and the second cover 20 are located with respect to the apparatus main body 90 is defined as the front side of the apparatus, and the upper surface side of the apparatus main body 90 is defined as the upper side of the apparatus. The width direction of the image forming apparatus 1 is a direction orthogonal to the front-rear direction and the up-down direction. The side that is on the left when facing the first cover 10 and the second cover 20 is defined as one side in the width direction. The front-rear direction, up-down direction, and width direction shown in each drawing from Fig. 2 onward are all displayed in correspondence with Fig. 1.

[0016] <Overall Configuration> As shown in Fig. 1, the image forming apparatus 1 includes an apparatus main body 90, a paper feed cassette 2C, an image forming unit 3, and a conveying unit (not shown). The apparatus main body 90 is a substantially box-shaped body, and has a discharge tray 90T on the upper surface thereof.

[0017] The apparatus main body 90 accommodates the paper feed cassette 2C and the image forming unit 3. The paper feed cassette 2C is located in the lower portion inside the apparatus main body 90, and accommodates a plurality of sheets in a stacked state. The image forming unit 3 is located in the upper portion inside the apparatus main body 90.

[0018] The image forming unit 3 is an electrophotographic image forming unit having multiple cartridges 3C, a photosensitive drum (not shown), a charging unit, a developing roller, a scanner unit, a fixing unit, etc. Each cartridge 3C contains toner of the corresponding color.

[0019] A transport unit (not shown) supplies sheets SH one by one from the paper feed cassette 2C to the image forming unit 3. The image forming unit 3 forms an image on the sheet SH. After that, a transport unit (not shown) transports the sheet SH with the image formed on it and discharges it into the discharge tray 90T.

[0020] As shown in Figure 2, the device body 90 has an upper wall 99 and a first opening 10H on its front side. In other words, the device body 90 has a first opening 10H. The upper wall 99 is a substantially flat plate shape that extends downward from the upper surface of the device body 90 and also extends in the width direction. The first opening 10H is located below the upper wall 99. The first opening 10H is a substantially rectangular opening in which the length in the width direction is greater than the length in the vertical direction.

[0021] The image forming unit 3 has a drawer 3D. The front side of the drawer 3D is located within the first opening 10H. Although not shown in the illustration, the drawer 3D detachably supports each cartridge 3C shown in Figure 1. Inside the main body 90 of the device, there is a guide rail that supports the drawer 3D so that it can be pulled forward from the mounting position shown in Figure 2. In other words, the first opening 10H is an opening for attaching and detaching each cartridge 3C to the drawer 3D.

[0022] As shown in Figure 1, the image forming apparatus 1 includes a first cover 10 and a second cover 20.

[0023] As shown in Figure 2, the first cover 10 is supported by the device body 90 so as to be able to swing around the pivot axis X10. The pivot axis X10 extends in the width direction at a position below the first opening 10H on the front side of the device body 90. The first cover 10 swings between a first closed position shown in Figures 1 and 3 and a first open position shown in Figure 2.

[0024] As shown in Figures 1 and 3, the first cover 10, when in the first closed position, stands upright and closes the first opening 10H. As shown in Figure 2, the first cover 10, when in the first open position, tilts forward and downward from the first closed position to open the first opening 10H.

[0025] In the following description of the shape of the components of the first cover 10, the state in which the first cover 10 is in the first closed position is used as the reference point with respect to the front-to-back and up-to-down directions.

[0026] As shown in Figures 2 and 3, the first cover 10 has a second opening 20H. In other words, the first cover 10 has a second opening 20H formed therein. The second opening 20H is formed in the lower part of the first cover 10. The second opening 20H is a substantially rectangular opening in which the length in the width direction is greater than the length in the vertical direction. The length in the width direction of the second opening 20H is greater than the maximum width of the sheet SH on which the image is formed by the image forming unit 3.

[0027] As shown in Figure 3, the second cover 20 is supported by the first cover 10 so as to be able to pivot around a pivot axis X20. The pivot axis X20 extends in the width direction at a position located below the upper edge of the second opening 20H on the front side of the first cover 10. The second cover 20 pivots between a second closed position shown in Figure 1 and a second open position shown in Figure 3.

[0028] As shown in Figure 1, the second cover 20, in the second closed position, stands upright and closes the second opening 20H. As shown in Figure 3, the second cover 20, in the second open position, tilts forward and downward from the second closed position, opening the second opening 20H.

[0029] In the following description of the shape of the components of the second cover 20, the state in which the second cover 20 is in the second closed position is used as the reference point with respect to the front-to-back and up-and-down directions.

[0030] When the second cover 20 is in the second open position, its upward-facing surface can support the sheet SH before it is transported toward the image forming unit 3. The second cover 20 is a multi-purpose tray for transporting multiple types of sheets SH with different sizes and thicknesses to the image forming unit 3.

[0031] The leading edge of the sheet SH, supported by the second cover 20, passes through the second opening 20H and is inserted to a position where it can be transported by a transport unit (not shown). In other words, the second opening 20H is an opening that allows the sheet SH, which is being transported toward the image forming unit 3 with the first cover 10 in the first closed position, to pass through.

[0032] When the user instructs the system to perform an image forming operation on a sheet SH supported by the second cover 20, a transport unit (not shown) supplies the sheets SH supported by the second cover 20 to the image forming unit 3 one by one. The image forming unit 3 forms an image on the sheet SH. Subsequently, a transport unit (not shown) transports the sheet SH with the formed image and discharges it into the discharge tray 90T.

[0033] As shown in Figure 2, when the toner in cartridge 3C becomes low and cartridge 3C needs to be replaced, the user swings the first cover 10 to the first open position and pulls the drawer 3D forward from its mounting position. The user then removes the cartridge 3C to be replaced from the drawer 3D, installs the new cartridge 3C into the drawer 3D, and pushes the drawer 3D back into its mounting position. Finally, the user swings the first cover 10 to the first closed position, completing the cartridge 3C replacement process.

[0034] Here, when the user swings the first cover 10 from the first closed position to the first open position, it is conceivable that the second cover 20 may unintentionally swing relative to the first cover 10. More specifically, when the first cover 10 is moved from the first closed position to the first open position, if the impact of reaching the first open position and stopping causes the second cover 20, which is in the second closed position, to move to the second open position, the second cover will be unnecessarily open, which is likely to make the user feel that the operation is not good.

[0035] Therefore, as described below, the image forming apparatus 1 is equipped with a configuration that restricts the swing of the second cover 20 relative to the first cover 10 when the first cover 10 swings from the first closed position to the first open position.

[0036] <First engaging portion, second engaging portion, and contact portion> As shown in Figure 4, the upper wall 99 of the device body 90, the upper end portion 10U of the first cover 10 in the first closed position, and the upper end portion 20U of the second cover 20 in the second closed position are aligned in the front-to-back direction.

[0037] The upper end portion 10U of the first cover 10 in the first closed position is located in front of the upper wall 99 of the device body 90. The upper end portion 20U of the second cover 20 in the second closed position is located in front of the upper end portion 10U of the first cover 10 in the first closed position.

[0038] As shown in Figures 2 and 3, two first placement positions PL1 are set on the upper end portion 10U of the first cover 10. Each first placement position PL1 is spaced apart from the others in the width direction.

[0039] As shown in Figure 3, two second placement positions PL2 are set on the upper end portion 20U of the second cover 20. Each second placement position PL2 is spaced apart from the others in the width direction. A second placement position PL2 located on one side in the width direction corresponds to a first placement position PL1 located on the other side in the width direction. A second placement position PL2 located on the other side in the width direction corresponds to a first placement position PL1 located on the other side in the width direction.

[0040] As shown in Figure 2, two third placement positions PL3 are set on the upper wall 99 of the device body 90. Each third placement position PL3 is spaced apart from the others in the width direction. The third placement position PL3 located on one side in the width direction corresponds to the first placement position PL1 and the second placement position PL2 located on the other side in the width direction. The third placement position PL3 located on the other side in the width direction corresponds to the first placement position PL1 and the second placement position PL2 located on the other side in the width direction.

[0041] As shown in Figure 4, the first cover 10 has a first engaging portion 11. The two first engaging portions 11 are located at the first position PL1 shown in Figure 3.

[0042] As shown in Figure 4, the first engaging portion 11 is integrally formed with the front end portion of the upper end portion 10U of the first cover 10. In other words, the first engaging portion 11 is fixedly attached to the first cover 10 in an immovable manner.

[0043] The first engaging portion 11 is a rectangular protrusion in side view that projects downward. The tip 11E of the first engaging portion 11 is a downward-facing flat surface that extends substantially horizontally in the front-rear direction.

[0044] The second cover 20 has a second engaging portion 21. The two second engaging portions 21 are located at the second position PL2 shown in Figure 3.

[0045] As shown in Figures 4 to 6, the second engaging portion 21 is supported by the upper end portion 20U of the second cover 20 so as to be able to pivot around the pivot axis X21. The pivot axis X21 is located on the rear side of the upper end portion 20U of the second cover 20 and extends in the width direction.

[0046] As shown in Figure 4, with the first cover 10 in the first closed position and the second cover 20 in the second closed position, the pivot axis X21 is slightly separated downward and forward from the tip 11E of the first engaging portion 11.

[0047] The second engaging portion 21 protrudes rearward from the pivot axis X21. The second engaging portion 21 has a hook shape with a claw 21N. The claw 21N is located at the rear portion of the second engaging portion 21 and protrudes upward.

[0048] A first inclined surface 21C is formed on the claw 21N. The first inclined surface 21C slopes downward backward from the apex of the claw 21N.

[0049] The second cover 20 has a spring support portion 21D, a biasing spring 21S, and a swing restricting portion 21G.

[0050] The spring support portion 21D is located below the second engagement portion 21 and protrudes backward in a cantilevered manner from the rear surface of the upper end portion 20U of the second cover 20.

[0051] The biasing spring 21S is a compression coil spring that stores restoring force by being compressed in the vertical direction. The biasing spring 21S is located between the second engaging portion 21 and the spring support portion 21D. The biasing spring 21S biases the second engaging portion 21 upward.

[0052] The oscillation restricting portion 21G is located above the second engaging portion 21. The oscillation restricting portion 21G is slightly separated upward and rearward from the oscillation axis X21.

[0053] As shown by the dashed lines in Figure 5, the second engaging portion 21 and the oscillation restricting portion 21G are shown, and as shown in Figure 6, the oscillation restricting portion 21G restricts the upward oscillation of the second engaging portion 21 by contacting it.

[0054] The second engaging portion 21 is pivotable between the engageable position shown in Figure 6 and the non-engagement position shown in Figure 4. The position of the second engaging portion 21 shown by the dashed line in Figure 5 is also the engageable position. The position of the second engaging portion 21 shown by the solid line in Figure 5 is between the engageable position and the non-engagement position. The biasing spring 21S biases the second engaging portion 21 toward the engageable position.

[0055] As shown in Figure 6, the second engaging portion 21 is in contact with the swing restricting portion 21G when in the engageable position and can engage with the first engaging portion 11 by the claw 21N. The first engaging portion 11 can engage with the second engaging portion 21 of the second cover 20 when in the second closed position.

[0056] As shown in Figure 4, the second engaging portion 21 is in an unengageable position because the apex of the claw 21N is separated downward from the tip 11E of the first engaging portion 11, thus preventing it from engaging with the first engaging portion 11.

[0057] As shown in Figure 4, the device body 90 has contact portions 91. Two contact portions 91 are located at the third arrangement positions PL3 shown in Figure 2.

[0058] As shown in Figure 4, the contact portion 91 is a columnar protrusion that projects forward from the front surface of the upper wall 99. The contact portion 91 enters the upper end portion 10U of the first cover 10 when the first cover 10 is in the first closed position. In this state, the front surface of the contact portion 91 faces the first engaging portion 11 with a small gap between it and the rear surface of the first engaging portion 11.

[0059] The contact portion 91 has a first sliding contact surface 91A. The first sliding contact surface 91A is a downward-facing flat surface that extends substantially horizontally in the front-rear direction. When the first cover 10 is in the first closed position, the first sliding contact surface 91A is located below the tip 11E of the first engaging portion 11. When the first cover 10 is in the first closed position, the tip 11E of the first engaging portion 11 is retracted above the claw 21N of the second engaging portion 21 relative to the first sliding contact surface 91A.

[0060] As shown in Figure 4, with the first cover 10 in the first closed position, the contact portion 91 is adjacent to the first engaging portion 11 from the opposite side of the second cover 20, i.e., from the rear. The contact portion 91 then causes the second engaging portion 21 to swing to the non-engagement position against the biasing spring 21S by having its first sliding contact surface 91A abut against the apex of the claw 21N of the second engaging portion 21.

[0061] As shown by the dashed lines in Figure 5, the second engaging portion 21 and the swing restricting portion 21G are shown, and as shown in Figure 6, the contact portion 91 swings the second engaging portion 21 to the engageable position by separating it from the second engaging portion 21.

[0062] <When the first cover is in the first closed position, and the second cover swings from the second closed position to the second open position> When the user performs an image forming operation on the sheet SH supported by the second cover 20, the second cover 20 is swung from the second closed position to the second open position while the first cover 10 is in the first closed position.

[0063] As shown in Figure 4, the second engaging portion 21, in which the apex of the claw 21N abuts against the first sliding contact surface 91A of the contact portion 91 and is in a non-engaging position, does not engage with the first engaging portion 11, as shown in Figure 5, and allows the second cover 20 to swing relative to the first cover 10.

[0064] Here, as shown in Figure 4, when the first cover 10 is in the first closed position, the tip 11E of the first engaging portion 11 is retracted above the claw 21N of the second engaging portion 21 relative to the first sliding contact surface 91A. Then, when the second cover 20 begins to swing from the second closed position toward the second open position, the first sliding contact surface 91A of the contact portion 91 slides against the claw 21N, thereby preventing the claw 21N of the second engaging portion 21 from receiving a load from the tip 11E of the first engaging portion 11.

[0065] <When the first cover is in the first closed position, and the second cover swings from the second open position to the second closed position> When the image forming operation on the sheet SH supported by the second cover 20 is completed, the user swings the second cover 20 from the second open position to the second closed position while the first cover 10 is in the first closed position. At this time, as shown by the dashed line in Figure 5, the second engaging portion 21, which is located in an engageable position away from the contact portion 91, moves closer to the first engaging portion 11. Then, just before the second cover 20 reaches the second closed position, as shown by the solid line in Figure 5, the first inclined surface 21C sequentially slides against the tip 11E of the first engaging portion 11 and the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion 21 to swing to an unengageable position. As a result, as shown in Figure 4, the apex of the claw 21N of the second engaging portion 21 comes into contact with the first sliding contact surface 91A of the contact portion 91, and the second cover 20 returns to the second closed position.

[0066] <When the second cover is in the second closed position, and the first cover swings from the first closed position to the first open position> When the user performs the replacement of cartridge 3C, with the second cover 20 in the second closed position, the first cover 10 is swung from the first closed position to the first open position.

[0067] As shown in Figure 6, the second engaging portion 21, which is located at an engagement position away from the contact portion 91, engages with the first engaging portion 11 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0068] <When the second cover is in the second closed position, and the first cover swings from the first open position to the first closed position> When the user finishes replacing cartridge 3C, with the second cover 20 in the second closed position, the first cover 10 is swung from the first open position to the first closed position. At this time, the second engaging portion 21, which is separated from the contact portion 91 and in an engageable position, moves closer to the first engaging portion 11. Then, just before the first cover 10 reaches the first closed position, the first inclined surface 21C slides against the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion 21 to swing to an unengageable position. As a result, as shown in Figure 4, the apex of the claw 21N of the second engaging portion 21 comes into contact with the first sliding contact surface 91A of the contact portion 91, and the first cover 10 returns to the first closed position.

[0069] <Effects and Effects> In the image forming apparatus 1 of Embodiment 1, as shown in Figure 4, the first engaging portion 11 of the first cover 10 is provided immovably on the first cover 10 and has a simple configuration that allows it to engage with the second cover 20 in the second closed position, making malfunctions less likely to occur.

[0070] The contact portion 91 of the main body 90 of the device also has a simple configuration that allows it to contact the second engaging portion 21, making malfunctions less likely.

[0071] Furthermore, the second engaging portion 21 of the second cover 20, which is located further away from the main body 90 than the first cover 10 and is more easily accessible to the user, is configured to swing between an engaging position and an unengaging position, allowing for easy replacement of parts, repairs, etc., in the event of damage or malfunction of the second engaging portion 21.

[0072] Therefore, the image forming apparatus 1 of Embodiment 1, with its configuration that restricts the swinging of the second cover 20 relative to the first cover 10 when the first cover 10 is opened, allows for easy maintenance work.

[0073] Furthermore, in this image forming apparatus 1, the second engaging portion 21 is pivotably supported by the second cover 20. This configuration allows the second engaging portion 21 to smoothly pivot between an engageable position and an unengageable position.

[0074] Furthermore, in this image forming apparatus 1, the second engaging portion 21 is hook-shaped and has a claw 21N that can engage with the first engaging portion 11. The second cover 20 has a biasing spring 21S that biases the second engaging portion 21 toward the engageable position. With this configuration, the second engaging portion 21 in the engageable position can reliably engage with the first engaging portion 11.

[0075] Furthermore, in this image forming apparatus 1, when the first cover 10 is in the first closed position, the contact portion 91 abuts against the claw 21N of the second engaging portion 21 adjacent to the first engaging portion 11 from the opposite side of the second cover 20, i.e., from the rear, thereby causing the second engaging portion 21 to swing to the non-engaging position against the biasing spring 21S. This configuration allows for an even simpler structure for the contact portion 91.

[0076] Furthermore, in this image forming apparatus 1, the contact portion 91 has a first sliding contact surface 91A that slides against the claw 21N when the first cover 10 begins to swing from the first closed position to the first open position. When the first cover 10 is in the first closed position, the tip 11E of the first engaging portion 11 is retracted above the claw 21N of the second engaging portion 21 relative to the first sliding contact surface 91A. With this configuration, the contact portion 91 can prevent the claw 21N of the second engaging portion 21 from receiving a load from the tip 11E of the first engaging portion 11 when the second cover 20 begins to swing from the second closed position to the second open position, thanks to the first sliding contact surface 91A.

[0077] Furthermore, in this image forming apparatus 1, as shown in Figure 5, a first inclined surface 21C is formed on the claw 21N of the second engaging portion 21. When the second cover 20 swings to the second closed position while the first cover 10 is in the first closed position, the first inclined surface 21C slides against the tip 11E of the first engaging portion 11 and the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion to swing to the non-engagement position. As shown in Figure 6, when the first cover 10 swings to the first closed position together with the second cover 20 which is in the second closed position, the first inclined surface 21C slides against the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion 21 to swing to the non-engagement position. With this first inclined surface 21C, the second engaging portion 21 can be reliably swung to the non-engagement position.

[0078] (Example 2) As shown in Figures 7 to 9, the image forming apparatus of Example 2 employs a second engagement part 22, a guide 26, and a biasing spring 22S instead of the second engagement part 21, spring support part 21D, biasing spring 21S, and oscillation restricting part 21G of the image forming apparatus 1 of Example 1.

[0079] The other components of Example 2 are the same as those of Example 1. Therefore, components identical to those of Example 1 are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0080] As shown in Figure 7, the guide 26 has an arm portion 26A and a cylindrical portion 26B.

[0081] The arm portion 26A protrudes rearward from the rear surface of the upper end portion 20U of the second cover 20. The position where the base of the arm portion 26A connects to the rear surface of the upper end portion 20U of the second cover 20 is approximately the same as the position where the base of the spring support portion 21D according to Embodiment 1 connects to the rear surface of the upper end portion 20U of the second cover 20.

[0082] The cylindrical portion 26B is a bottomed cylindrical shape that protrudes upward from the rear portion of the arm portion 26A. The cylindrical portion 26B has two guide grooves 26C. Each guide groove 26C is an elongated hole located in the front and rear portions of the cylindrical portion 26B and extending in the vertical direction.

[0083] The second engaging portion 22 is a cylinder with a horizontal, flat lower surface and an inclined upper surface. The outer diameter of the second engaging portion 22 is slightly smaller than the inner diameter of the cylindrical portion 26B.

[0084] The second engaging portion 22 has two ribs 22R. The front rib 22R protrudes forward from the front portion of the outer circumferential surface of the second engaging portion 22 and extends in the vertical direction. The rear rib 22R protrudes backward from the rear portion of the outer circumferential surface of the second engaging portion 22 and extends in the vertical direction.

[0085] The second engaging portion 22 is inserted into the cylindrical portion 26B with each rib 22R inserted into each guide groove 26C. The guide 26 prevents the second engaging portion 22 from rotating through the guide grooves 26C into which each rib 22R enters. The guide 26 guides the second engaging portion 22 so that it can move linearly in the vertical direction through the cylindrical portion 26B. In other words, the second engaging portion 22 is supported so that it can move linearly by the upper end portion 20U of the second cover 20.

[0086] The second engaging portion 22 is hook-shaped and has a claw 22N that protrudes upward. A first inclined surface 22C is formed on the claw 22N. The second inclined surface 22C slopes downward backward from the apex of the claw 22N.

[0087] The biasing spring 22S is a compression coil spring that stores restoring force when compressed in the vertical direction. The biasing spring 22S is located between the second engaging portion 22 and the bottom surface of the cylindrical portion 26B. The biasing spring 22S biases the second engaging portion 22 upward.

[0088] As shown in Figure 8, the second engaging portion 22 and guide 26 are indicated by dashed lines, and as shown in Figure 9, each guide groove 26C restricts the upward linear movement of the second engaging portion 22 by its upper end abutting against the upper end of each rib 22R.

[0089] The second engaging portion 22 is linearly movable between the engageable position shown in Figure 9 and the non-engagement position shown in Figure 7. The position of the second engaging portion 22 shown by the dashed line in Figure 8 is also the engageable position. The position of the second engaging portion 22 shown by the solid line in Figure 8 is between the engageable position and the non-engagement position. The biasing spring 22S biases the second engaging portion 22 toward the engageable position.

[0090] As shown in Figure 9, in the engageable position, the second engaging portion 22 has the upper end of each rib 22R in contact with the upper end of each guide groove 26C, and can engage with the first engaging portion 11 by the claw 22N. The first engaging portion 11 can engage with the second engaging portion 22 of the second cover 20 in the second closed position.

[0091] As shown in Figure 7, the second engaging portion 22 is in an unengaged position because the apex of the claw 22N is separated downward from the tip 11E of the first engaging portion 11, thus preventing it from engaging with the first engaging portion 11.

[0092] With the first cover 10 in the first closed position, the tip 11E of the first engaging portion 11 is retracted above the claw 22N of the second engaging portion 22 relative to the first sliding contact surface 91A.

[0093] With the first cover 10 in the first closed position, the contact portion 91 is adjacent to the first engaging portion 11 from the opposite side of the second cover 20, i.e., from the rear. The contact portion 91 then moves the second engaging portion 22 to the non-engagement position against the biasing spring 22S by having its first sliding contact surface 91A contact the apex of the claw 22N of the second engaging portion 22.

[0094] As shown in Figure 8, the second engaging portion 22 and the guide 26 are indicated by dashed lines, and as shown in Figure 9, the contact portion 91 moves the second engaging portion 22 to the engageable position by separating it from the second engaging portion 22.

[0095] <When the first cover is in the first closed position, and the second cover swings from the second closed position to the second open position> When the first cover 10 is in the first closed position and the second cover 20 swings from the second closed position to the second open position, as shown in Figure 7, the second engaging portion 22, in which the apex of the claw 22N abuts against the first sliding contact surface 91A of the contact portion 91 and is in a non-engaging position, does not engage with the first engaging portion 11, as shown in Figure 8, and allows the second cover 20 to swing relative to the first cover 10.

[0096] Here, as shown in Figure 7, when the first cover 10 is in the first closed position, the tip 11E of the first engaging portion 11 is retracted above the claw 22N of the second engaging portion 22 relative to the first sliding contact surface 91A. Then, when the second cover 20 begins to swing from the second closed position toward the second open position, the first sliding contact surface 91A of the contact portion 91 slides against the claw 22N, thereby preventing the claw 22N of the second engaging portion 22 from receiving a load from the tip 11E of the first engaging portion 11.

[0097] <When the first cover is in the first closed position, and the second cover swings from the second open position to the second closed position> When the second cover 20 swings from the second open position to the second closed position while the first cover 10 is in the first closed position, the second engaging portion 22, which is located in an engageable position away from the contact portion 91, moves closer to the first engaging portion 11, as shown by the dashed line in Figure 8. Then, just before the second cover 20 reaches the second closed position, the first inclined surface 22C slides in sequentially against the tip 11E of the first engaging portion 11 and the first sliding contact surface 91A of the contact portion 91, as shown by the solid line in Figure 8, causing the second engaging portion 22 to move in a straight line to the non-engagement position. As a result, as shown in Figure 7, the apex of the claw 22N of the second engaging portion 22 comes into contact with the first sliding contact surface 91A of the contact portion 91, and the second cover 20 returns to the second closed position.

[0098] <When the second cover is in the second closed position, and the first cover swings from the first closed position to the first open position> When the second cover 20 is in the second closed position and the first cover 10 swings from the first closed position to the first open position, as shown in Figure 9, the second engaging portion 22, which is located in an engageable position away from the contact portion 91, engages with the first engaging portion 11 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0099] <When the second cover is in the second closed position, and the first cover swings from the first open position to the first closed position> When the first cover 10 swings from the first open position to the first closed position while the second cover 20 is in the second closed position, the second engaging portion 22, which is located in an engageable position away from the contact portion 91, moves closer to the first engaging portion 11. Then, just before the first cover 10 reaches the first closed position, the first inclined surface 22C slides against the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion 22 to move in a non-engagement position. As a result, as shown in Figure 7, the apex of the claw 22N of the second engaging portion 22 comes into contact with the first sliding contact surface 91A of the contact portion 91, and the first cover 10 returns to the first closed position.

[0100] <Effects and Effects> The image forming apparatus of Example 2, like the image forming apparatus 1 of Example 1, has a configuration that restricts the swinging of the second cover 20 relative to the first cover 10 when the first cover 10 is opened, allowing for easy maintenance work.

[0101] Furthermore, in this image forming apparatus, as shown in Figure 7, the second engaging portion 22 is supported so as to be able to move linearly on the second cover 20. This configuration allows for a reduction in the space required for the second engaging portion 22.

[0102] Furthermore, in this image forming apparatus, the second cover 20 has a guide 26 that guides the second engaging portion 22 so that it can move linearly. With this configuration, the second engaging portion 22 can move smoothly linearly between the engageable position and the non-engagement position.

[0103] Furthermore, in this image forming apparatus, the second engaging portion 22 has a hook shape with a claw 22N that can engage with the first engaging portion 11. The second cover 20 has a biasing spring 22S that biases the second engaging portion 22 toward the engageable position. With this configuration, the second engaging portion 22 in the engageable position can reliably engage with the first engaging portion 11.

[0104] Furthermore, in this image forming apparatus, as shown in Figure 8, a first inclined surface 22C is formed on the claw 22N of the second engaging portion 22. When the second cover 20 swings to the second closed position while the first cover 10 is in the first closed position, the first inclined surface 22C slides against the tip 11E of the first engaging portion 11 and the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion to move directly to the non-engagement position. As shown in Figure 9, when the first cover 10 swings to the first closed position together with the second cover 20 which is in the second closed position, the first inclined surface 22C slides against the first sliding contact surface 91A of the contact portion 91, causing the second engaging portion 22 to move directly to the non-engagement position. With this first inclined surface 22C, the second engaging portion 22 can be swung to the non-engagement position with high reliability.

[0105] (Example 3) As shown in Figures 10 to 13, the image forming apparatus of Embodiment 3 is equipped with a first engaging portion 13, a second engaging portion 23, and a contact portion 93, instead of the first engaging portion 11, second engaging portion 21, and contact portion 91 of the image forming apparatus 1 of Embodiment 1.

[0106] The other components of Example 3 are the same as those of Example 1. Therefore, components identical to those of Example 1 are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0107] In Example 3, the front-to-back direction in which the upper wall 99 of the device body 90, the upper end portion 10U of the first cover 10 in the first closed position, and the upper end portion 20U of the second cover 20 in the second closed position are aligned is an example of the "first direction" of the present invention. The forward direction is an example of "one of the first directions" of the present invention. The vertical direction is an example of the "second direction" of the present invention. The width direction is an example of the "third direction" of the present invention.

[0108] As shown in Figures 10 and 11, the first cover 10 has a first engaging portion 13. The two first engaging portions 13 are located at the first position PL1 shown in Figure 3.

[0109] As shown in Figure 10, the first engaging portion 13 is fixed to the rear portion of the lower surface of the upper end portion 10U of the first cover 10. In other words, the first engaging portion 13 is fixed to the first cover 10 in an immovable manner.

[0110] The first engaging portion 13 protrudes briefly downward, then bends and extends forward. As shown in Figure 11, the tip 13E of the first engaging portion 13 is hook-shaped with a claw that protrudes toward the other side in the width direction.

[0111] As shown in Figures 10 and 11, the second cover 20 has a second engaging portion 23. The two second engaging portions 23 are located at the second position PL2 shown in Figure 3.

[0112] As shown in Figures 11 to 13, the second engaging portion 23 is supported by the upper end portion 20U of the second cover 20 so as to be able to pivot around the pivot axis X23. The pivot axis X23 is located on the rear side of the upper end portion 20U of the second cover 20 and extends in the vertical direction.

[0113] As shown in Figure 11, with the first cover 10 in the first closed position and the second cover 20 in the second closed position, the pivot axis X23 is separated from the tip 13E of the first engaging portion 13 in one of the directions: downward, forward, and widthwise.

[0114] The second engaging portion 23 protrudes rearward from the pivot axis X23. The second engaging portion 23 has a hook shape with a claw 23N. The claw 23N is located on the rear portion of the second engaging portion 23 and protrudes toward one side in the width direction.

[0115] A second inclined surface 23C is formed on the claw 23N. The second inclined surface 23C is inclined such that it shifts toward the other side in the width direction as it extends backward from the apex of the claw 23N.

[0116] The second engaging portion 23 has a swing restricting portion 23G. The swing restricting portion 23G protrudes briefly from the front end of the second engaging portion 23 toward one side in the width direction.

[0117] The second cover 20 has a spring support portion 23D and a biasing spring 23S.

[0118] The spring support portion 23D is located on the other side in the width direction from the second engaging portion 23 and protrudes backward in a cantilevered manner from the rear surface of the upper end portion 20U of the second cover 20.

[0119] The biasing spring 23S is a compression coil spring that stores restoring force by being compressed in the width direction. The biasing spring 23S is located between the second engaging portion 23 and the spring support portion 23D. The biasing spring 23S biases the second engaging portion 23 toward one side in the width direction.

[0120] As shown in Figures 11, 12(c), and 13(c), the oscillation restricting portion 23G contacts the rear surface of the upper end portion 20U of the second cover 20, thereby restricting the oscillation of the second engaging portion 23 in one direction in the width direction.

[0121] The second engaging portion 23 is pivotable between the engageable position shown in Figures 11, 12(c), and 13(c), and the non-engagement position shown in Figures 12(a) and 13(a). The position of the second engaging portion 23 shown in Figures 12(b) and 13(b) is between the engageable position and the non-engagement position. The biasing spring 23S biases the second engaging portion 23 toward the engageable position. The claw 23N of the second engaging portion 23 moves in the width direction.

[0122] As shown in Figure 13(c), in the engageable position, the second engaging portion 23 has its swing restricting portion 23G in contact with the rear surface of the upper end portion 20U of the second cover 20, and is engageable with the first engaging portion 13 by the claw 23N. The first engaging portion 13 is engageable with the second engaging portion 23 of the second cover 20 in the second closed position.

[0123] As shown in Figures 12(a) and 13(a), the second engaging portion 23 is in an unengaged position because the apex of the claw 23N is separated from the tip 13E of the first engaging portion 13 toward the other side in the width direction, thereby preventing engagement with the first engaging portion 13.

[0124] As shown in Figures 10 and 11, the device body 90 has contact portions 93. Two contact portions 93 are located at the third arrangement positions PL3 shown in Figure 2.

[0125] The contact portion 93 is a roughly columnar protrusion that projects forward from the front surface of the upper wall 99. The contact portion 93 enters the upper end portion 10U of the first cover 10 when the first cover 10 is in the first closed position. In this state, the tip 93E of the contact portion 93 is located close to the front surface of the upper end portion 10U of the first cover 10.

[0126] As shown in Figure 10, the upper surface of the contact portion 93 is slightly separated downward from the lower surface of the first engaging portion 13. In other words, the contact portion 93 is adjacent to the first engaging portion 13 in the vertical direction.

[0127] As shown in Figure 11, the contact portion 93 has a second sliding contact surface 93A. The second sliding contact surface 93A is a surface facing the other side in the width direction, and as it moves forward from the middle part in the front-rear direction of the contact portion 93, it shifts toward the other side in the width direction and inclins to approach the claw 23N of the second engaging portion 23, and then extends forward.

[0128] With the first cover 10 in the first closed position, the forward-extending portion of the second sliding surface 93A is located on the other side in the width direction from the tip 13E of the first engaging portion 13. With the first cover 10 in the first closed position, the tip 13E of the first engaging portion 13 is located retracted from the claw 23N of the second engaging portion 23 toward one side in the width direction relative to the second sliding surface 93A.

[0129] A second inclined surface 93C is formed at the tip 93E of the contact portion 93. The second inclined surface 93C is connected to the front end of the second sliding contact surface 93A and is inclined so as it moves forward, it shifts toward one side in the width direction.

[0130] With the first cover 10 in the first closed position and the second cover 20 in the second closed position, the rear end of the second sliding contact surface 93A of the contact portion 93 faces the apex of the claw 23N of the second engaging portion 23 with a gap in the width direction. By separating the contact portion 93 from the claw 23N of the second engaging portion 23, the contact portion 93 positions the second engaging portion 23, which is biased by the biasing spring 23S, in an engageable position.

[0131] As shown in Figures 12(a) and 13(a), the contact portion 93 causes the second engaging portion 23 to swing to a non-engaging position against the biasing spring 23S by the second sliding contact surface 93A sliding against the claw 23N.

[0132] As shown in Figures 12(c) and 13(c), the contact portion 93 moves rearward from the second engaging portion 23, thereby causing the second engaging portion 23 to swing to an engageable position.

[0133] <When the first cover is in the first closed position, and the second cover swings from the second closed position to the second open position> With the first cover 10 in the first closed position, when the second cover 20 begins to swing from the second closed position to the second open position, as shown in Figure 12(a), the contact portion 93 causes the second engaging portion 23 to swing to the non-engaging position against the biasing spring 23S by the second sliding contact surface 93A sliding against the claw 23N. Then, as shown in Figure 12(b), the second engaging portion 23, located in the non-engaging position, does not engage with the first engaging portion 13 and allows the second cover 20 to swing relative to the first cover 10. Subsequently, as shown in Figure 12(c), the second engaging portion 23 moves away from the contact portion 93 and is positioned in the engageable position.

[0134] Here, as shown in Figure 12(a), when the second cover 20 begins to swing from the second closed position to the second open position, the tip 13E of the first engaging portion 13 is retracted from the claw 23N of the second engaging portion 23 in one direction in the width direction relative to the second sliding contact surface 93A. Therefore, the claw 23N of the second engaging portion 23 is prevented from receiving a load from the tip 13E of the first engaging portion 13.

[0135] <When the first cover is in the first closed position, and the second cover swings from the second open position to the second closed position> When the second cover 20 swings from the second open position to the second closed position while the first cover 10 is in the first closed position, as shown in Figure 12(c), the second engaging portion 23, which is located in an engageable position away from the contact portion 93, approaches the first engaging portion 13 in that position. Then, just before the second cover 20 reaches the second closed position, as shown in Figures 12(b) and (a), the second inclined surface 23C and the second inclined surface 93C slide into contact, causing the second engaging portion 23 to swing to an unengageable position. As a result, as shown in Figure 11, the second engaging portion 23 passes without engaging with the first engaging portion 13, and the second cover 20 returns to the second closed position.

[0136] <When the second cover is in the second closed position, and the first cover swings from the first closed position to the first open position> When the first cover 10 swings from the first closed position to the first open position while the second cover 20 is in the second closed position, the first engaging portion 13 moves forward together with the second engaging portion 23, as shown in Figures 13(a) and (b). At this time, the contact portion 93 causes the second engaging portion 23 to swing to the non-engaging position against the biasing spring 23S by the second sliding contact surface 93A sliding against the claw 23N.

[0137] Then, as shown in Figure 13(c), the second engaging portion 23 moves away from the contact portion 93 to a position where it can be engaged, and engages with the first engaging portion 13 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0138] <When the second cover is in the second closed position, and the first cover swings from the first open position to the first closed position> When the first cover 10 swings from the first open position to the first closed position while the second cover 20 is in the second closed position, as shown in Figure 13(c), the second engaging portion 23, which is located in an engageable position away from the contact portion 93, approaches the first engaging portion 13. Then, just before the first cover 10 reaches the first closed position, as shown in Figures 13(b) and (a), the second inclined surface 23C and the second inclined surface 93C slide into contact, causing the second engaging portion 23 to swing to an unengageable position. As a result, as shown in Figure 11, the second engaging portion 23 passes without engaging with the first engaging portion 13, and the first cover 10 returns to the first closed position.

[0139] <Effects and Effects> The image forming apparatus of Example 3, like the image forming apparatus 1 of Examples 1 and 2, has a configuration that restricts the swinging of the second cover 20 relative to the first cover 10 when the first cover 10 is opened, allowing for easy maintenance work.

[0140] Furthermore, in this image forming apparatus, as shown in Figure 11, the second engaging portion 23 has a hook shape with a claw 23N that can engage with the first engaging portion 13. The second cover 20 has a biasing spring 23S that biases the second engaging portion 23 toward the engageable position. With this configuration, the second engaging portion 23 in the engageable position can reliably engage with the first engaging portion 13.

[0141] Furthermore, in this image forming apparatus, as shown in Figure 10, the contact portion 93 protrudes forward and is adjacent to the first engaging portion 13 in the vertical direction. As shown in Figures 12 and 13, the claw 23N of the second engaging portion 23 moves in the width direction. As shown in Figure 11, when the first cover 10 is in the first closed position and the second cover 20 is in the second closed position, the contact portion 93 separates from the claw 23N of the second engaging portion 23, thereby positioning the second engaging portion 23, which is biased by the biasing spring 23S, in an engageable position. As shown in Figure 12(a), when the first cover 10 is in the first closed position and the second cover 20 begins to swing from the second closed position toward the second open position, the contact portion 93 contacts the claw 23N of the second engaging portion 23, thereby swinging the second engaging portion 23 to an unengageable position against the biasing spring 23S. With this configuration, the contact portion 93 can apply a load to the second cover 20 that prevents the second cover 20 from separating from the device body 90 when the first cover 10 is in the first closed position and the second cover 20 is in the second closed position. Furthermore, with this configuration, the contact portion 93 can make the user feel a click sensation when the second cover 20 begins to swing from the second closed position to the second open position.

[0142] Furthermore, in this image forming apparatus, as shown in Figures 12(a) and 13(a), the contact portion 93 has a second sliding contact surface 93A that slides against the claw 23N when the second cover 20 begins to swing from the second closed position to the second open position. The second sliding contact surface 93A is inclined so that as it moves forward, it shifts toward the other side in the width direction and approaches the claw 23N. The tip 13E of the first engaging portion 13 is positioned further back from the claw 23N of the second engaging portion 23 toward one side in the width direction than the second sliding contact surface 93A. With this configuration, when the second cover 20 begins to swing from the second closed position to the second open position, the contact portion 93 can prevent the claw 23N of the second engaging portion 23 from receiving a load from the tip 13E of the first engaging portion 13 by the second sliding contact surface 93A. Furthermore, this configuration allows the contact portion 93 to provide the user with a click sensation when the second cover 20 begins to swing from the second closed position to the second open position, thanks to the second sliding contact surface 93A.

[0143] Furthermore, in this image forming apparatus, as shown in Figures 12 and 13, a second inclined surface 23C is formed on the claw 23N of the second engaging portion 23. A second inclined surface 93C is formed on the tip 93E of the contact portion 93. The second inclined surface 23C slides against the tip 93E of the contact portion 93 when the second cover 20 swings to the second closed position while the first cover 10 is in the first closed position, and when the first cover 10 swings to the first closed position together with the second cover 20 which is in the second closed position, causing the second engaging portion 23 to swing to the non-engagement position. The second inclined surface 93C slides against the claw 23N of the second engaging portion 23 when the second cover 20 swings to the second closed position while the first cover 10 is in the first closed position, and when the first cover 10 swings to the first closed position together with the second cover 20 which is in the second closed position, causing the second engaging portion 23 to swing to the non-engagement position. This configuration allows the second engaging portion 23 to swing to a non-engaging position while the second inclined surfaces 23C and 93C prevent the tip 13E of the first engaging portion 13 from receiving a load from the claw 23N of the second engaging portion 23.

[0144] Although the present invention has been described above in reference to Examples 1 to 3, it goes without saying that the present invention is not limited to Examples 1 to 3, and can be applied with appropriate modifications without departing from its spirit.

[0145] In Examples 1 to 3, the image forming apparatus of the present invention was embodied as an image forming apparatus 1 equipped with an image forming function, but the present invention is not limited to this configuration. For example, the configuration of the present invention may be applied to a multifunction device equipped with an image forming function and an image reading function.

[0146] For example, the present invention also includes a configuration in which, in the image forming apparatus 1 of Embodiment 1, the image forming unit 3 does not have a drawer 3D, and only one cartridge 3C is housed inside the apparatus body 90, and that one cartridge 3C is attached to and removed from the first opening 10H for replacement.

[0147] In Example 3, the front-rear direction is an example of the "first direction," the forward direction is an example of "one of the first directions," the up-down direction is an example of the "second direction," and the width direction is an example of the "third direction." However, the present invention is not limited to this configuration. For example, the "second direction" may be the width direction and the "third direction" may be the up-down direction. [Explanation of Symbols]

[0148] 1…Image forming apparatus, 3C…Cartridge SH...Sheet, 3...Image forming unit 90...Device main body, 10H...1st opening 10...First cover, 20H...Second opening 20...Second cover, 11, 13...First engaging part 21, 22, 23...Second engaging part, 91, 93...Abutting part 26... Guide, 21N, 22N, 23N... Claw 21S, 22S, 23S... biasing springs 91A...First sliding contact surface, 11E, 13E...Tip of the first engaging portion 21C, 22C...1st inclined surface, 93A...2nd sliding surface 93E...Tip of the contact area, 23C, 93C...Second inclined surface

Claims

1. It has a cartridge that contains toner, and an image forming unit that forms an image on a sheet, The apparatus body housing the image forming unit, the apparatus body having a first opening for attaching and detaching the cartridge, A first cover is movably supported on the main body of the apparatus and moves between a first closed position that closes the first opening and a first open position that opens the first opening, the first cover having a second opening formed therein for allowing a sheet being conveyed toward the image forming section to pass through when in the first closed position, A second cover that is pivotably supported by the first cover and pivots between a second closed position that closes the second opening and a second open position that opens the second opening, the second cover being capable of supporting a sheet before it is conveyed toward the image forming unit when in the second open position, An image forming apparatus comprising, The first cover has a first engaging portion that is immovably provided to the first cover and is capable of engaging with the second cover in the second closed position. The second cover has a second engaging portion that is movable between an engageable position in which it can engage with the first engaging portion and an inengagement position in which it cannot engage with the first engaging portion. The device body has a contact portion that moves the second engaging portion to the non-engagement position by contacting the second engaging portion, and moves the second engaging portion to the engagement position by moving it away from the second engaging portion. When the first cover is in the first closed position, and the second cover swings from the second closed position to the second open position, the second engaging portion, which is in contact with the contact portion and in the non-engagement position, does not engage with the first engaging portion, and allows the swing of the second cover relative to the first cover. An image forming apparatus characterized in that, when the first cover swings from the first closed position to the first open position while the second cover is in the second closed position, the second engaging portion, which is located at the engageable position away from the contact portion, is configured to engage with the first engaging portion to restrict the swinging of the second cover relative to the first cover.

2. The image forming apparatus according to claim 1, wherein the second engaging portion is pivotably supported by the second cover.

3. The image forming apparatus according to claim 1, wherein the second engaging portion is supported so as to be able to move in line with the second cover.

4. The image forming apparatus according to claim 3, wherein the second cover has a guide that allows the second engaging portion to move in a straight line.

5. The second engaging portion has a hook shape with a claw that can engage with the first engaging portion. The image forming apparatus according to any one of claims 1 to 4, wherein the second cover has a biasing spring that biases the second engaging portion toward the engageable position.

6. The image forming apparatus according to claim 5, wherein, with the first cover in the first closed position, the contact portion abuts against the claw of the second engaging portion from the opposite side of the second cover relative to the first engaging portion, thereby moving the second engaging portion to the non-engaging position against the biasing spring.

7. The contact portion has a first sliding contact surface that slides against the claw when the first cover begins to move from the first closed position to the first open position. The image forming apparatus according to claim 6, wherein, with the first cover in the first closed position, the tip of the first engaging portion is retracted from the claw relative to the first sliding contact surface.

8. The claw of the second engaging portion has a first inclined surface formed therein. The first inclined surface slides against the tip of the first engaging portion and the first sliding contact surface of the contact portion when the second cover swings to the second closed position while the first cover is in the first closed position, thereby moving the second engaging portion to the non-engaging position. The image forming apparatus according to claim 7, wherein the first inclined surface slides against the first sliding contact surface of the contact portion when the first cover swings to the first closed position together with the second cover which is in the second closed position, thereby moving the second engaging portion to the non-engaging position.

9. If the direction in which the main body of the device, the first cover in the first closed position, and the second cover in the second closed position are aligned is defined as the first direction, The second cover in the second closed position is located in one direction in the first direction relative to the first cover in the first closed position. The contact portion protrudes in one of the first directions and is adjacent to the first engagement portion in a second direction perpendicular to the first direction. The claw of the second engaging portion moves in a third direction perpendicular to the first and second directions. With the first cover in the first closed position and the second cover in the second closed position, the contact portion moves away from the claw of the second engaging portion, thereby positioning the second engaging portion, which is biased by the biasing spring, in the engageable position. The image forming apparatus according to claim 5, wherein, with the first cover in the first closed position, when the second cover begins to swing from the second closed position toward the second open position, the contact portion contacts the claw of the second engaging portion, thereby moving the second engaging portion to the non-engaging position against the biasing spring.

10. The contact portion has a second sliding contact surface that slides against the claw when the second cover begins to move from the second closed position to the second open position. The second sliding surface is inclined such that as it advances toward one of the first directions, it approaches the claw in the third direction. The image forming apparatus according to claim 9, wherein the tip of the first engaging portion is positioned retracted from the claw relative to the second sliding surface.

11. The image forming apparatus according to claim 10, wherein a second inclined surface is formed on one of the claws of the second engaging portion and the tip of the contact portion, which slides against the other claw of the second engaging portion and the tip of the contact portion when the second cover swings to the second closed position while the first cover is in the first closed position, and when the first cover swings to the first closed position together with the second cover which is in the second closed position, thereby moving the second engaging portion to the non-engaging position.

Images