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, 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 contact portion 31 contacts the apparatus body 90, thereby contacting the second engaging portion 21 and positioning the second engaging portion 21 in a non-engagement position. The second engaging portion 21 does not engage with the first engaging portion 11, allowing 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 contact portion 31 separates from the apparatus body 90, thereby separating from the second engaging portion 21 and positioning the second engaging portion 21 in an engagement position. The second engaging portion 21 engages with the first engaging portion 11, restricting 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 cover is supported by the exterior of the apparatus main body to be openable and closable. A feed tray door corresponding to a second cover is supported by the cartridge door to be openable and closable. The cartridge door has a lock mechanism.

[0003] With the cartridge door in the closed state, the rotating cam of the lock mechanism abuts against the exterior, and the tip end portion 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 rotating cam of the lock mechanism separates from the exterior, and the tip end portion of the stopper of the lock mechanism engages with the tray door opening of the feed tray door, so that the swinging of the feed tray door relative to the cartridge door is restricted.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0005]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, in the above conventional image forming apparatus, 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 it is difficult to easily perform maintenance work such as component replacement and repair when breakage or malfunction of the stopper or the like occurs.

[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 can engage 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 first cover further has a contact portion that is movable to abut the second engaging portion to position the second engaging portion in the non-engagement position, and to move away from the second engaging portion to position the second engaging portion in the engagement position, 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 contact portion contacts the device body, thereby contacting the second engaging portion and positioning the second engaging portion in the non-engagement position. The second engaging portion, in the non-engagement position, does not engage with the first engaging portion and allows the second cover to swing relative to the first cover. The device is 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 contact portion moves away from the main body of the device, thereby moving away from the second engaging portion and positioning the second engaging portion in the engageable position, and the second engaging portion, located in the engageable position, engages 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 second engaging portion of the second cover, which is located further from the main body of the apparatus than the first cover and is 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.

[0010] 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]

[0011] [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 showing section AA of Figure 4. [Figure 6] Figures 6(a) to 6(c) are schematic partial cross-sectional views similar to those in Figure 5, 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 7] Figures 7(a) and 7(b) are schematic partial cross-sectional views similar to those in Figure 5, 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 8] Figure 8 is a schematic partial cross-sectional view of the image forming apparatus of Embodiment 2, 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 9] Figure 9 is a schematic partial cross-sectional view similar to Figure 8, 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 10] Figure 10 is a schematic partial cross-sectional view similar to Figure 8, 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 11] Figure 11 relates to the image forming apparatus of Embodiment 3 and is a schematic partial cross-sectional view similar to Figure 8, 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 12]FIG. 12 is a schematic partial cross-sectional view similar to FIG. 11, and is a diagram for explaining the relative relationship among 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] FIG. 13 is a schematic partial cross-sectional view similar to FIG. 11, and is a diagram for explaining the relative relationship among 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]

[0012] Hereinafter, Examples 1 to 1 in which the present invention is embodied will be described with reference to the drawings.

[0013] (Example 1) As shown in FIG. 1, an image forming apparatus 1 of Example 1 is an example of a specific embodiment 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 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 comes to 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 after FIG. 2 are all displayed in correspondence with FIG. 1.

[0014] <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 its upper surface.

[0015] 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 part of 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 part of the apparatus main body 90.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] As shown in Figure 1, the image forming apparatus 1 includes a first cover 10 and a second cover 20.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] <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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] In Example 1, 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.

[0039] As shown in Figures 4 and 5, 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.

[0040] As shown in Figure 4, the first engaging portion 11 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 11 is fixed to the first cover 10 in an immovable manner.

[0041] The first engaging portion 11 protrudes briefly downward, then bends and extends forward. As shown in Figure 5, the tip 11E of the first engaging portion 11 is hook-shaped with a claw that protrudes toward the other side in the width direction.

[0042] As shown in Figures 4 and 5, 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.

[0043] As shown in Figures 5 to 7, 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 vertical direction.

[0044] As shown in Figure 5, 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 separated from the tip 11E of the first engaging portion 11 in either the forward or widthwise direction.

[0045] 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 on the rear portion of the second engaging portion 21 and protrudes toward one side in the width direction.

[0046] A first inclined surface 21C is formed on the claw 21N. The first inclined surface 21C is inclined such that it shifts toward the other side in the width direction as it extends backward from the apex of the claw 21N.

[0047] The second engaging portion 21 has a swing restricting portion 21G. The swing restricting portion 21G protrudes briefly from the front end of the second engaging portion 21 toward one side in the width direction.

[0048] The second cover 20 has a spring support portion 21D and a biasing spring 21S.

[0049] The spring support portion 21D is located on the other side in the width direction from 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.

[0050] The biasing spring 21S is a compression coil spring that stores restoring force by being compressed in the width 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 toward one side in the width direction.

[0051] As shown in Figures 5, 6(c), and 7(b), the oscillation restricting portion 21G contacts the rear surface of the upper end portion 20U of the second cover 20, thereby restricting the oscillation of the second engaging portion 21 in one direction in the width direction.

[0052] The second engaging portion 21 is pivotable between the engageable position shown in Figures 5, 6(c), and 7, and the non-engagement position shown in Figure 6(a). The position of the second engaging portion 21 shown in Figure 6(b) is between the engageable position and the non-engagement position. The biasing spring 21S biases the second engaging portion 21 toward the engageable position. The claw 21N of the second engaging portion 21 moves in the width direction.

[0053] As shown in Figure 7(b), in the engageable position, the second engaging portion 21 has its swing restricting portion 21G 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 11 by the claw 21N. The first engaging portion 11 is engageable with the second engaging portion 21 of the second cover 20 in the second closed position.

[0054] As shown in Figure 6(a), the second engaging portion 21 is in a non-engaging position because the apex of the claw 21N is separated from the tip 11E of the first engaging portion 11 toward the other side in the width direction, thereby preventing engagement with the first engaging portion 11.

[0055] As shown in Figures 4 and 5, the first cover 10 further has contact portions 31. The two contact portions 31 are located at the first placement positions PL1 shown in Figure 3.

[0056] As shown in Figure 4, the upper end portion 10U of the first cover 10 has a support shaft 31A. The support shaft 31A extends downward from the lower surface of the upper end portion 10U of the first cover 10. The support shaft 31A is a cylinder centered on a pivot axis X31 that extends vertically and is located on the rear end side of the lower surface of the upper end portion 10U. The lower end of the support shaft 31A is located below the first engaging portion 11.

[0057] The contact portion 31 is pivotably supported at the lower end of the support shaft 31A. In other words, the contact portion 31 is pivotably supported by the upper end 10U of the first cover 10 around the pivot axis X31.

[0058] As shown in Figure 5, the contact portion 31 has a protruding portion 37 and an extended portion 38.

[0059] The projection 37 is a roughly columnar convex portion that protrudes forward from the pivot axis X31. The tip 37E of the projection 37 is located close to the front surface of the upper end portion 10U of the first cover 10.

[0060] As shown in Figure 4, the upper surface of the protrusion 37 is slightly separated downward from the lower surface of the first engaging portion 11. In other words, the protrusion 37 is adjacent to the first engaging portion 11 in the vertical direction.

[0061] As shown in Figure 5, the extension portion 38 extends from the pivot axis X31 in one direction in the width direction and then branches off. The portion of the extension portion 38 that branches forward and then bends in one direction in the width direction is the spring support portion 38D. The portion of the extension portion 38 that branches backward is the pivot restricting portion 38G.

[0062] The first cover 10 has a spring support portion 31D, a swing restricting portion 31G, and a biasing spring 31S. It has.

[0063] The spring support portion 31D is located at the upper end portion 10U of the first cover 10, forward of the spring support portion 38D, and protrudes toward the other side in the width direction.

[0064] The oscillation restricting portion 31G is located at the upper end portion 10U of the first cover 10, behind the spring support portion 38D, and protrudes toward the other side in the width direction.

[0065] The biasing spring 31S is a compression coil spring that stores restoring force by being compressed in the front-rear direction. The biasing spring 31S is located between the spring support portion 31D and the spring support portion 38D. The biasing spring 31S biases the contact portion 31 in the clockwise direction on the paper as shown in Figures 5 to 7. In other words, the biasing spring 31S biases the contact portion 31 so that the protruding portion 37 moves in one direction in the width direction.

[0066] The contact portion 31 is pivotable between the restricted position shown in Figures 5 and 6 and the permissible position shown in Figure 7. The biasing spring 31S biases the contact portion 31 toward the permissible position. The protruding portion 37 of the contact portion 31 moves in the width direction.

[0067] As shown in Figures 5 and 6, with the contact portion 31 in the restricted position, the oscillation restricting portion 38G is in contact with the front surface of the upper wall 99 of the device body 90, and the spring support portion 38D is separated forward from the oscillation restricting portion 31G.

[0068] As shown in Figure 7, with the contact portion 31 in the allowable position, the oscillation restricting portion 38G is separated from the front surface of the upper wall 99 of the device body 90, and the spring support portion 38D is in contact with the oscillation restricting portion 31G.

[0069] In other words, the contact portion 31 is positioned in the restricted position when the first cover 10 is in the first closed position, and the oscillation restricting portion 38G comes into contact with the front surface of the upper wall 99 of the device body 90. The contact portion 31 swings to the permitted position when the first cover 10 begins to swing from the first closed position to the first open position, and the oscillation restricting portion 38G moves away from the front surface of the upper wall 99 of the device body 90.

[0070] In the following description of the shape of the protruding portion 37, the reference point is the state in which the contact portion 31 is in the restricted position in the front-rear and width directions.

[0071] As shown in Figure 5, the protruding portion 37 has a first sliding contact surface 37A. The first sliding contact surface 37A is a surface facing the other side in the width direction, and as it proceeds forward from the middle part in the front-rear direction of the protruding portion 37, it shifts toward the other side in the width direction and inclins to approach the claw 21N of the second engaging portion 21, and then extends forward.

[0072] With the first cover 10 in the first closed position, the forward-extending portion of the first sliding contact surface 37A is located on the other side in the width direction from the tip 11E of the first engaging portion 11. With the first cover 10 in the first closed position, that is, with the swing restricting portion 38G of the contact portion 31 in contact with the front surface of the upper wall 99 of the device body 90, the tip 11E of the first engaging portion 11 is retracted from the first sliding contact surface 37A toward one side in the width direction from the claw 21N of the second engaging portion 21.

[0073] A first inclined surface 37C is formed at the tip 37E of the protruding portion 37. The first inclined surface 37C is connected to the front end of the first sliding contact surface 37A and is inclined so as it moves forward, it shifts toward one side in the width direction.

[0074] 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 first sliding contact surface 37A of the protrusion 37 faces the apex of the claw 21N of the second engaging portion 21 with a gap in the width direction. By separating the protrusion 37 from the claw 21N of the second engaging portion 21, the second engaging portion 21, which is biased by the biasing spring 21S, is positioned in an engageable position.

[0075] As shown in Figure 6(a), the protruding portion 37 of the contact portion 31 in the restricted position causes the second engaging portion 21 to swing to the non-engagement position against the biasing spring 21S by sliding the first sliding contact surface 37A against the claw 21N, thereby restricting the second engaging portion 21 from engaging with the first engaging portion 11.

[0076] As shown in Figures 6(b) and (c), the protruding portion 37 of the contact portion 31 in the restricted position moves rearward from the second engaging portion 21, thereby causing the second engaging portion 21 to swing to the engageable position.

[0077] As shown in Figure 7, the protruding portion 37 of the contact portion 31 in the allowable position moves away from the second engaging portion 21 in one direction in the width direction, thereby positioning the second engaging portion 21 in an engageable position and allowing the second engaging portion 21 to engage with the first engaging portion 11.

[0078] In other words, the contact portion 31 is movable so as to contact the second engaging portion 21 to position the second engaging portion 21 in a non-engagement position, and so as to move away from the second engaging portion 21 to position the second engaging portion 21 in an engagement position.

[0079] <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.

[0080] Then, as shown in Figure 6(a), when the second cover 20 begins to swing from the second closed position to the second open position, the protruding portion 37 of the contact portion 31 in the restricting position causes the first sliding contact surface 37A to slide against the claw 21N, causing the second engaging portion 21 to swing to the non-engaging position against the biasing spring 21S. Then, as shown in Figure 6(b), the second engaging portion 21, located in the non-engaging position, does not engage with the first engaging portion 11, allowing the second cover 20 to swing relative to the first cover 10. Subsequently, as shown in Figure 6(c), the second engaging portion 21 moves away from the protruding portion 37 and is positioned in the engageable position.

[0081] In other words, 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, the contact portion 31 contacts the device body 90, thereby contacting the second engaging portion 21 and positioning the second engaging portion 21 in a non-engagement position. The second engaging portion 21, in the non-engagement position, does not engage with the first engaging portion 11 and allows the second cover 20 to swing relative to the first cover 10.

[0082] Here, as shown in Figure 6(a), when the second cover 20 begins to swing from the second closed position to the second open position, the tip 11E of the first engaging portion 11 is retracted from the claw 21N of the second engaging portion 21 in one direction in the width direction relative to the first sliding contact surface 37A. Therefore, the claw 21N of the second engaging portion 21 is prevented from receiving a load from the tip 11E of the first engaging portion 11.

[0083] <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 in Figure 6(c), the second engaging portion 21, which is located in an engageable position away from the protruding portion 37, approaches the first engaging portion 11. Then, just before the second cover 20 reaches the second closed position, as shown in Figures 6(b) and (a), the first inclined surface 21C and the first inclined surface 37C slide into contact, causing the second engaging portion 21 to swing to an unengageable position. As a result, as shown in Figure 5, the second engaging portion 21 passes without engaging with the first engaging portion 11, and the second cover 20 returns to the second closed position.

[0084] <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.

[0085] As shown in Figure 7(a), the first engaging portion 11 moves forward together with the second engaging portion 21. At this time, the swing restricting portion 38G separates from the front surface of the upper wall 99 of the device body 90, causing the contact portion 31 to swing to an acceptable position. The protruding portion 37 of the contact portion 31 in the acceptable position is separated from the second engaging portion 21 in one direction in the width direction, allowing the second engaging portion 21, which is in the engageable position, to engage with the first engaging portion 11. As a result, as shown in Figure 7(b), the second engaging portion 21 engages with the first engaging portion 11 and restricts the swing of the second cover 20 relative to the first cover 10.

[0086] In other words, 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, the contact portion 31 separates from the device body 90, thereby separating from the second engaging portion 21 and positioning the second engaging portion 21 in an engageable position. The second engaging portion 21, in the engageable position, engages with the first engaging portion 11 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0087] <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 the 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, as shown in Figure 7(b), the second engaging portion 21, which is located in the engageable position away from the protrusion 37, approaches the first engaging portion 11 in that position. Then, as shown in Figure 7(a), even when the first cover 10 is about to reach the first closed position, the second engaging portion 21 remains in the engageable position and passes without sliding against the first sliding contact surface 37A of the protrusion 37 of the contact portion 31, which is in the allowable position. Subsequently, as shown in Figure 5, the swing restricting portion 38G comes into contact with the front surface of the upper wall 99 of the device body 90, causing the contact portion 31 to swing to its original position and the first cover 10 to return to the first closed position.

[0088] <Effects and Effects> In the image forming apparatus 1 of Embodiment 1, as shown in Figure 5, the second engaging portion 21 of the second cover 20, which is further away from the apparatus body 90 than the first cover 10 and more easily accessible to the user, is configured to be movable between an engaging position and an unengaging position. This allows for easy replacement of parts, repairs, etc., in the event of damage or malfunction of the second engaging portion 21.

[0089] 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.

[0090] Furthermore, in this image forming apparatus 1, the contact portion 31 is pivotably supported on the first cover 10. This configuration allows the contact portion 31 to smoothly allow or restrict the pivoting of the second cover 20 relative to the first cover 10.

[0091] 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 move smoothly between an engageable position and an unengageable position.

[0092] 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.

[0093] Furthermore, in this image forming apparatus, as shown in Figure 4, the protruding portion 37 protrudes forward and is adjacent to the first engaging portion 11 in the vertical direction. As shown in Figures 6 and 7, the claw 21N of the second engaging portion 21 moves in the width direction. As shown in Figure 5, when the first cover 10 is in the first closed position and the second cover 20 is in the second closed position, the protruding portion 37 moves away from the claw 21N of the second engaging portion 21, thereby positioning the second engaging portion 21, which is biased by the biasing spring 21S, in an engageable position. As shown in Figure 6(a), when the second cover 20 begins to swing from the second closed position toward the second open position while the first cover 10 is in the first closed position, the protruding portion 37 contacts the claw 21N of the second engaging portion 21, thereby swinging the second engaging portion 21 to an unengageable position against the biasing spring 21S. With this configuration, the protrusion 37 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 protrusion 37 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.

[0094] Furthermore, in this image forming apparatus 1, the protruding portion 37 has a first sliding contact surface 37A that slides against the claw 21N when the second cover 20 begins to move from the second closed position to the second open position. The first sliding contact surface 37A is inclined so that as it moves forward, it shifts toward the other side in the width direction and approaches the claw 21N. When the contact portion 31 is in contact with the apparatus body 90, the tip 11E of the first engaging portion 11 is in a position that is retracted from the claw 21N relative to the first sliding contact surface 37A. With this configuration, when the second cover 20 begins to move from the second closed position to the second open position, the protruding portion 37 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 by the first sliding contact surface 37A. Furthermore, this configuration allows the protruding portion 37 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, due to the first sliding contact surface 37A.

[0095] Furthermore, in this image forming apparatus, as shown in Figure 6, a first inclined surface 21C is formed on the claw 21N of the second engaging portion 21. A first inclined surface 37C is formed on the tip 37E of the protruding portion 37. 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 37E of the protruding portion 37, causing the second engaging portion 21 to swing to the non-engagement position. 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 37C slides against the claw 21N of the second engaging portion 21, causing the second engaging portion 21 to swing to the non-engagement position. With this configuration, the tip 11E of the first engaging portion 11 is prevented from receiving a load from the claw 21N of the second engaging portion 21 by the first inclined surfaces 21C and 37C, while the second engaging portion 21 can be swung to the non-engagement position.

[0096] (Example 2) As shown in Figures 8 to 10, the image forming apparatus of Embodiment 2 is equipped with a first engaging portion 12, a second engaging portion 22, and a contact portion 32 instead of the first engaging portion 11, second engaging portion 21, and contact portion 31 of the image forming apparatus 1 of Embodiment 1.

[0097] 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.

[0098] As shown in Figure 8, the first cover 10 has a first engaging portion 12. The two first engaging portions 12 are located at the first position PL1 shown in Figure 3.

[0099] As shown in Figure 8, the first engaging portion 12 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 12 is fixedly attached to the first cover 10.

[0100] The first engaging portion 12 is a rectangular protrusion in side view that projects downward. The tip 12E of the first engaging portion 12 is a downward-facing flat surface that extends substantially horizontally in the front-rear direction.

[0101] The second cover 20 has a second engaging portion 22. The two second engaging portions 22 are located at the second position PL2 shown in Figure 3.

[0102] As shown in Figures 8 to 10, the second engaging portion 22 is supported by the upper end portion 20U of the second cover 20 so as to be able to pivot around the pivot axis X22. The pivot axis X22 is located on the rear side of the upper end portion 20U of the second cover 20 and extends in the width direction.

[0103] As shown in Figure 8, with the first cover 10 in the first closed position and the second cover 20 in the second closed position, the pivot axis X22 is slightly separated downward and forward from the tip 12E of the first engaging portion 12.

[0104] The second engaging portion 22 protrudes rearward from the pivot axis X22. The second engaging portion 22 has a hook shape with a claw 22N. The claw 22N is located at the rear portion of the second engaging portion 22 and protrudes upward.

[0105] A first inclined surface 22C is formed on the claw 22N. The first inclined surface 22C slopes downward backward from the apex of the claw 22N.

[0106] The second cover 20 has a spring support portion 22D, a biasing spring 22S, and a swing restricting portion 22G.

[0107] The spring support portion 22D is located below the second engagement portion 22 and protrudes backward in a cantilevered manner from the rear surface of the upper end portion 20U of the second cover 20.

[0108] 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 spring support portion 22D. The biasing spring 22S biases the second engaging portion 22 upward.

[0109] The oscillation restricting portion 22G is located above the second engaging portion 22. The oscillation restricting portion 22G is slightly separated upward and rearward from the oscillation axis X22.

[0110] As shown by the dashed lines in Figure 9, the second engaging portion 22 and the oscillation restricting portion 22G are shown, and as shown in Figure 10, the oscillation restricting portion 22G restricts the upward oscillation of the second engaging portion 22 by contacting it.

[0111] The second engaging portion 22 is pivotable between the engageable position shown in Figure 10 and the non-engagement position shown in Figure 8. The position of the second engaging portion 22 shown by the dashed line in Figure 9 is also the engageable position. The position of the second engaging portion 22 shown by the solid line in Figure 9 is between the engageable position and the non-engagement position. The biasing spring 22S biases the second engaging portion 22 toward the engageable position.

[0112] As shown in Figure 10, the second engaging portion 22 is in contact with the swing restricting portion 22G when in the engageable position and can engage with the first engaging portion 12 by the claw 22N. The first engaging portion 12 can engage with the second engaging portion 22 of the second cover 20 when in the second closed position.

[0113] As shown in Figure 8, when the second engaging portion 22 is in the non-engagement position, the apex of the claw 22N is separated downward from the tip 12E of the first engaging portion 12, making it impossible to engage with the first engaging portion 12.

[0114] The first cover 10 further has contact portions 32. The two contact portions 32 are located at the first placement positions PL1 shown in Figure 3.

[0115] The upper end portion 10U of the first cover 10 has a support wall 32A. The support wall 32A extends downward from the rear end of the upper end portion 10U of the first cover 10. Two support holes 32H are formed in the support wall 32A so as to penetrate in the front-rear direction. The support holes 32H are spaced apart from each other in the vertical direction.

[0116] The contact portion 32 is a member with a roughly "U" shape in side view, having a spring housing portion 32L. The spring housing portion 32L is a groove that is recessed forward from the rear surface of the contact portion 32 to the vicinity of the front surface of the contact portion 32.

[0117] The contact portion 32 has two supported protrusions 32M. The upper supported protrusion 32M is located above the spring housing portion 32L and protrudes backward. The lower supported protrusion 32M is located below the spring housing portion 32L and protrudes backward. A stepped portion 32D is formed on the front end side of each supported protrusion 32M in the contact portion 32.

[0118] As shown in Figures 8 to 10, each supported protrusion 32M is supported so as to be able to move linearly in the front-rear direction by each support hole 32H of the support wall 32A. In other words, the contact portion 32 is supported so as to be able to move linearly in the front-rear direction by the upper end portion 10U of the first cover 10.

[0119] The first cover 10 has a biasing spring 32S. The biasing spring 32S is a tension coil spring that stores restoring force when pulled in the front-rear direction. The biasing spring 32S is housed in the spring housing section 32L.

[0120] The front end of the biasing spring 32S is locked to the contact portion 32. The rear end of the biasing spring 32S is locked to the support wall 32A. The biasing spring 32S biases the contact portion 32 to move backward.

[0121] The contact portion 32 is capable of moving in a straight line between the restricted position shown in Figures 8 and 9 and the permissible position shown in Figure 10. The biasing spring 32S biases the contact portion 32 toward the permissible position.

[0122] As shown in Figures 8 and 9, with the contact portion 32 in the restricted position, the rear end of each supported protrusion 32M is in contact with the front surface of the upper wall 99 of the device body 90. In this state, the front surface of the contact portion 32 faces the first engaging portion 12 with a small gap between it and the rear surface of the first engaging portion 12.

[0123] As shown in Figure 10, with the contact portion 32 in the allowable position, the rear end of each supported protrusion 32M is separated from the front surface of the upper wall 99 of the device body 90, and each stepped portion 32D is in contact with the support wall 32A. In this state, the front surface of the contact portion 32 is separated rearward from the rear surface of the first engaging portion 12.

[0124] In other words, the contact portion 32 is positioned in a restricted position when the first cover 10 is in the first closed position, as the rear end of each supported projection 32M contacts the front surface of the upper wall 99 of the device body 90. The contact portion 32 moves in a straight line to an acceptable position when the first cover 10 begins to swing from the first closed position to the first open position, as the rear end of each supported projection 32M moves away from the front surface of the upper wall 99 of the device body 90.

[0125] As shown in Figure 8, the contact portion 32 has a second sliding contact surface 32A. The second sliding contact surface 32A is a downward-facing flat surface located in front of the lower supported protrusion 32M, and extends substantially horizontally in the front-rear direction. When the first cover 10 is in the first closed position, the second sliding contact surface 32A is located below the tip 12E of the first engaging portion 12. When the first cover 10 is in the first closed position, the tip 12E of the first engaging portion 12 is retracted above the claw 22N of the second engaging portion 22 relative to the second sliding contact surface 32A.

[0126] With the first cover 10 in the first closed position, the contact portion 32 in the restricting position is adjacent to the first engaging portion 12 from the opposite side of the second cover 20, i.e., from the rear. The contact portion 32 in the restricting position causes the second engaging portion 22 to be positioned in an unengageable position against the biasing spring 22S by the second sliding contact surface 32A of the second engaging portion 22 coming into contact with the apex of the claw 22N of the second engaging portion 22.

[0127] As shown in Figure 9, the contact portion 32 in the restricting position prevents the second engaging portion 22, which is located in the non-engagement position, from engaging with the first engaging portion 12 by the second sliding contact surface 32A sliding against the claw 22N.

[0128] As shown by the dashed lines in Figure 9, the second engaging portion 22 and the swing restricting portion 22G are moved backward by the contact portion 32 in the restricting position, thereby causing the second engaging portion 22 to swing to the engageable position.

[0129] As shown in Figure 10, the contact portion 32 in the allowable position moves rearward from the second engaging portion 22, thereby positioning the second engaging portion 22 in an engageable position and allowing the second engaging portion 22 to engage with the first engaging portion 12.

[0130] In other words, the contact portion 32 is movable so as to contact the second engaging portion 22 to position the second engaging portion 22 in a non-engagement position, and to move away from the second engaging portion 22 to position the second engaging portion 22 in an engagement position.

[0131] <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 8, the second engaging portion 22, which is in a non-engagement position because the apex of the claw 22N abuts against the second sliding contact surface 32A of the contact portion 32 in the restricting position, does not engage with the first engaging portion 12, as shown in Figure 9, and allows the second cover 20 to swing relative to the first cover 10.

[0132] In other words, 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, the contact portion 32 contacts the device body 90, thereby contacting the second engaging portion 22 and positioning the second engaging portion 22 in a non-engagement position. The second engaging portion 22, in the non-engagement position, does not engage with the first engaging portion 12 and allows the second cover 20 to swing relative to the first cover 10.

[0133] Here, as shown in Figure 8, with the first cover 10 in the first closed position, the tip 12E of the first engaging portion 12 is retracted above the claw 22N of the second engaging portion 22 relative to the second sliding contact surface 32A. Then, when the second cover 20 begins to swing from the second closed position toward the second open position, the second sliding contact surface 32A of the contact portion 32 in the restricting position slides against the claw 22N, thereby preventing the claw 22N of the second engaging portion 22 from receiving a load from the tip 12E of the first engaging portion 12.

[0134] <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 the engageable position away from the contact portion 32 in the restricting position, moves closer to the first engaging portion 12, as shown by the dashed line in Figure 9. Then, just before the second cover 20 reaches the second closed position, the first inclined surface 22C sequentially slides against the tip 12E of the first engaging portion 12 and the second sliding contact surface 32A of the contact portion 32 in the restricting position, as shown by the solid line in Figure 9, causing the second engaging portion 22 to swing to the non-engagement position. As a result, as shown in Figure 8, the apex of the claw 22N of the second engaging portion 22 comes into contact with the second sliding contact surface 32A of the contact portion 32 in the restricting position, and the second cover 20 returns to the second closed position.

[0135] <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 10, the rear end of each supported protrusion 32M moves away from the front surface of the upper wall 99 of the device body 90, and the contact portion 32 moves in a straight line to the allowable position. The second engaging portion 22, which is located in an engageable position away from the contact portion 32 in the allowable position, engages with the first engaging portion 12 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0136] In other words, 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, the contact portion 32 separates from the device body 90, thereby separating from the second engaging portion 22 and positioning the second engaging portion 22 in an engageable position. The second engaging portion 22, in the engageable position, engages with the first engaging portion 12 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0137] <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 the engageable position away from the contact portion 32 in the allowable position, approaches the first engaging portion 12 without changing its position. Then, just before the first cover 10 reaches the first closed position, the rear end of each supported protrusion 32M comes into contact with the front surface of the upper wall 99 of the device body 90, causing the contact portion 32 to move in a straight line from the allowable position to the restricted position. Consequently, the first inclined surface 22C slides against the second sliding contact surface 32A of the contact portion 32, which is moving in a straight line to the restricted position, causing the second engaging portion 22 to swing to the non-engagement position. As a result, as shown in Figure 8, the second engaging portion 22 comes into a state where the apex of the claw 22N comes into contact with the second sliding contact surface 32A of the contact portion 32, and the first cover 10 returns to the first closed position.

[0138] <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.

[0139] Furthermore, in this image forming apparatus, the contact portion 32 is supported so as to be able to move linearly on the first cover 10. This configuration allows for a reduction in the space required for the contact portion 32.

[0140] Furthermore, in this image forming apparatus, the second engaging portion 22 is pivotably supported by the second cover 20. This configuration allows the second engaging portion 22 to smoothly pivot between an engageable position and an unengageable position.

[0141] Furthermore, in this image forming apparatus, the second engaging portion 22 is hook-shaped and has a claw 22N that can engage with the first engaging portion 12. 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 12.

[0142] Furthermore, in this image forming apparatus, when the first cover 10 is in the first closed position, the contact portion 32 abuts against the claw 22N of the second engaging portion 22 adjacent to the first engaging portion 12 from the opposite side of the second cover 20, i.e., from the rear, thereby causing the second engaging portion 22 to swing to the non-engaging position against the biasing spring 22S. This configuration allows for an even simpler structure for the contact portion 32.

[0143] Furthermore, in this image forming apparatus, the contact portion 32 has a second sliding contact surface 32A that slides against the claw 22N 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 12E of the first engaging portion 12 is retracted above the claw 22N of the second engaging portion 22 relative to the second sliding contact surface 32A. With this configuration, the contact portion 32 can prevent the claw 22N of the second engaging portion 22 from receiving a load from the tip 12E of the first engaging portion 12 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 32A.

[0144] Furthermore, in this image forming apparatus, as shown in Figure 9, a second 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 second inclined surface 22C slides against the tip 12E of the first engaging portion 12 and the second sliding contact surface 32A of the contact portion 32, moving the second engaging portion 22 to the non-engagement position. As shown in Figure 10, 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 second inclined surface 22C slides against the second sliding contact surface 32A of the contact portion 32, moving the second engaging portion 22 to the non-engagement position. With this second inclined surface 22C, the second engaging portion 22 can be reliably swung to the non-engagement position.

[0145] (Example 3) As shown in Figures 11 to 13, the image forming apparatus of Embodiment 3 employs a second engagement part 23, a guide 26, and a biasing spring 23S instead of the second engagement part 22, spring support part 22D, biasing spring 22S, and oscillation restricting part 22G of the image forming apparatus of Embodiment 2.

[0146] The other components of Example 3 are the same as those of Example 2. Therefore, components identical to those of Example 2 are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0147] As shown in Figure 11, the guide 26 has an arm portion 26A and a cylindrical portion 26B.

[0148] 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 22D according to Embodiment 2 connects to the rear surface of the upper end portion 20U of the second cover 20.

[0149] 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.

[0150] The second engaging portion 23 is a cylinder with a horizontal, flat lower surface and an inclined upper surface. The outer diameter of the second engaging portion 23 is slightly smaller than the inner diameter of the cylindrical portion 26B.

[0151] The second engaging portion 23 has two ribs 23R. The front rib 23R protrudes forward from the front portion of the outer circumferential surface of the second engaging portion 23 and extends in the vertical direction. The rear rib 23R protrudes backward from the rear portion of the outer circumferential surface of the second engaging portion 23 and extends in the vertical direction.

[0152] The second engaging portion 23 is inserted into the cylindrical portion 26B with each rib 23R inserted into each guide groove 26C. The guide 26 prevents the second engaging portion 23 from rotating through the guide grooves 26C into which each rib 23R enters. The guide 26 guides the second engaging portion 23 so that it can move linearly in the vertical direction through the cylindrical portion 26B. In other words, the second engaging portion 23 is supported so that it can move linearly by the upper end portion 20U of the second cover 20.

[0153] The second engaging portion 23 is hook-shaped and has a claw 23N that protrudes upward. A first inclined surface 23C is formed on the claw 23N. The second inclined surface 23C slopes downward backward from the apex of the claw 23N.

[0154] The biasing spring 23S is a compression coil spring that stores restoring force by being compressed in the vertical direction. The biasing spring 23S is located between the second engaging portion 23 and the bottom surface of the cylindrical portion 26B. The biasing spring 23S biases the second engaging portion 23 upward.

[0155] As shown by the dashed lines in Figure 12, the second engaging portion 23 and the guide 26, and as shown in Figure 13, each guide groove 26C restricts the upward linear movement of the second engaging portion 23 by its upper end contacting the upper end of each rib 23R.

[0156] The second engaging portion 23 is linearly movable between the engageable position shown in Figure 13 and the non-engagement position shown in Figure 11. The position of the second engaging portion 23 shown by the dashed line in Figure 12 is also the engageable position. The position of the second engaging portion 23 shown by the solid line in Figure 12 is a position between the engageable position and the non-engagement position. The biasing spring 23S biases the second engaging portion 23 toward the engageable position.

[0157] As shown in Figure 13, in the engageable position, the second engaging portion 23 has the upper end of each rib 23R in contact with the upper end of each guide groove 26C, and is engageable with the first engaging portion 12 by the claw 23N. The first engaging portion 12 is engageable with the second engaging portion 23 of the second cover 20 in the second closed position.

[0158] As shown in Figure 11, the second engaging portion 23 is in an unengageable position because the apex of the claw 23N is separated downward from the tip 12E of the first engaging portion 12, thus preventing it from engaging with the first engaging portion 12.

[0159] With the first cover 10 in the first closed position, the tip 12E of the first engaging portion 12 is retracted above the claw 23N of the second engaging portion 23 relative to the second sliding contact surface 32A.

[0160] With the first cover 10 in the first closed position, the contact portion 32 in the restricting position is adjacent to the first engaging portion 12 from the opposite side of the second cover 20, i.e., from the rear. The contact portion 32 in the restricting position causes the second engaging portion 23 to be positioned in an unengageable position against the biasing spring 23S by the second sliding contact surface 32A of the second engaging portion 23 contacting the apex of the claw 23N of the second engaging portion 23.

[0161] As shown in Figure 12, the contact portion 32 in the restricting position prevents the second engaging portion 23, which is located in the non-engagement position, from engaging with the first engaging portion 12 by the second sliding contact surface 32A sliding against the claw 23N.

[0162] As shown by the dashed lines in Figure 12, the second engaging portion 23 and the swing restricting portion 23G are moved backward by the contact portion 32 in the restricting position, thereby causing the second engaging portion 23 to swing to the engageable position.

[0163] As shown in Figure 13, the contact portion 32 in the allowable position moves rearward from the second engaging portion 23, thereby positioning the second engaging portion 23 in an engageable position and allowing the second engaging portion 23 to engage with the first engaging portion 12.

[0164] <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 11, the second engaging portion 23, which is in a non-engaging position because the apex of the claw 23N abuts against the second sliding contact surface 32A of the contact portion 32 in the restricting position, does not engage with the first engaging portion 12, as shown in Figure 12, and allows the second cover 20 to swing relative to the first cover 10.

[0165] Here, as shown in Figure 11, with the first cover 10 in the first closed position, the tip 12E of the first engaging portion 12 is retracted above the claw 23N of the second engaging portion 23 relative to the second sliding contact surface 32A. Then, when the second cover 20 begins to swing from the second closed position toward the second open position, the second sliding contact surface 32A of the contact portion 32 in the restricting position slides against the claw 23N, thereby preventing the claw 23N of the second engaging portion 23 from receiving a load from the tip 12E of the first engaging portion 12.

[0166] <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 23, which is located in the engageable position away from the contact portion 32 in the restricting position, moves closer to the first engaging portion 12, as shown by the dashed line in Figure 12. Then, just before the second cover 20 reaches the second closed position, the first inclined surface 23C sequentially slides against the tip 12E of the first engaging portion 12 and the second sliding contact surface 32A of the contact portion 32 in the restricting position, as shown by the solid line in Figure 12, causing the second engaging portion 23 to swing to the non-engagement position. As a result, as shown in Figure 11, the apex of the claw 23N of the second engaging portion 23 comes into contact with the second sliding contact surface 32A of the contact portion 32 in the restricting position, and the second cover 20 returns to the second closed position.

[0167] <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 13, the rear end of each supported protrusion 32M moves away from the front surface of the upper wall 99 of the device body 90, and the contact portion 32 moves in a straight line to the allowable position. The second engaging portion 23, which is located in an engageable position away from the contact portion 32 in the allowable position, engages with the first engaging portion 12 to restrict the swinging of the second cover 20 relative to the first cover 10.

[0168] <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 23, which is located in an engageable position away from the contact portion 32 in the allowable position, approaches the first engaging portion 12 in that position. Then, just before the first cover 10 reaches the first closed position, the rear end of each supported protrusion 32M comes into contact with the front surface of the upper wall 99 of the device body 90, causing the contact portion 32 to move in a straight line from the allowable position to the restricted position. Consequently, the first inclined surface 23C slides against the second sliding contact surface 32A of the contact portion 32, which is moving in a straight line to the restricted position, 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 comes into a state where the apex of the claw 23N comes into contact with the second sliding contact surface 32A of the contact portion 32, and the first cover 10 returns to the first closed position.

[0169] <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.

[0170] Furthermore, in this image forming apparatus, the second engaging portion 23 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 23.

[0171] Furthermore, in this image forming apparatus, the second cover 20 has a guide 26 that guides the second engaging portion 23 so that it can move linearly. With this configuration, the second engaging portion 23 can move smoothly linearly between the engageable position and the non-engagement position.

[0172] Furthermore, in this image forming apparatus, the second engaging portion 23 has a hook shape with a claw 23N that can engage with the first engaging portion 12. 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 12.

[0173] Furthermore, in this image forming apparatus, as shown in Figure 12, a second inclined surface 23C is formed on 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, the second inclined surface 23C slides against the tip 12E of the first engaging portion 12 and the second sliding contact surface 32A of the contact portion 32, moving the second engaging portion 23 to the non-engagement position. As shown in Figure 13, 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 second inclined surface 23C slides against the second sliding contact surface 32A of the contact portion 32, moving the second engaging portion 23 to the non-engagement position. With this second inclined surface 23C, the second engaging portion 23 can be swung to the non-engagement position with high reliability.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] In Example 1, 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]

[0178] 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, 12...First engaging part 21, 22, 23...second engagement part, 31, 32...contact part 26... Guide, 21N, 22N, 23N... Claws of the second engaging part 21S, 22S, 23S... biasing spring, 37... protruding part 37A...First sliding contact surface, 11E, 12E...Tip of the first engaging portion 37E...Tip of the protrusion, 21C, 37C...First inclined surface 32A...Second sliding surface, 22C, 23C...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 can engage 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 first cover further has a contact portion that is movable to abut the second engaging portion to position the second engaging portion in the non-engagement position, and to move away from the second engaging portion to position the second engaging portion in the engagement position, 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 contact portion contacts the device body, thereby contacting the second engaging portion and positioning the second engaging portion in the non-engagement position. The second engaging portion, in the non-engagement position, does not engage with the first engaging portion and allows the second cover to swing 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 contact portion moves away from the main body of the apparatus, thereby moving away from the second engaging portion and positioning the second engaging portion in the engageable position, and the second engaging portion, located in the engageable position, engages 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 contact portion is pivotably supported by the first cover.

3. The image forming apparatus according to claim 1, wherein the contact portion is supported so as to be able to move in a straight line with respect to the first cover.

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

5. 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.

6. The image forming apparatus according to claim 5, wherein the second cover has a guide that allows the second engaging portion to move in a straight line.

7. 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 6, wherein the second cover has a biasing spring that biases the second engaging portion toward the engageable position.

8. The second engaging portion has a hook shape with a claw that can engage with the first engaging portion. The second cover has a biasing spring that biases the second engaging portion toward the engageable position. 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 has a projection that 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 protrusion 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 2, 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 protrusion contacts the claw of the second engaging portion, thereby moving the second engaging portion to the non-engaging position against the biasing spring.

9. The protrusion has a first 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 first 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 8, wherein, in a state in which the contact portion is in contact with the main body of the apparatus, the tip of the first engaging portion is retracted from the claw relative to the first sliding contact surface.

10. The image forming apparatus according to claim 9, wherein one of the claws of the second engaging portion and the tip of the protruding portion has a first inclined surface formed thereon, which slides against the other claw of the second engaging portion and the tip of the protruding 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.

11. The second engaging portion has a hook shape with a claw that can engage with the first engaging portion. The second cover has a biasing spring that biases the second engaging portion toward the engageable position. The image forming apparatus according to claim 3, 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.

12. The contact portion has a second 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 11, 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 second sliding contact surface.

13. A second inclined surface is formed on the claw of the second engaging portion. The second inclined surface slides against the tip of the first engaging portion and the second 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 12, wherein the second inclined surface slides against the second 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.

Images