Image forming apparatus

Abstract

The invention provides an image forming apparatus. An image forming apparatus includes a main body frame and a process unit, the process unit including: a unit frame that is removable by being pulled out from the main body frame toward one side in a first direction; a plurality of developing cartridges mounted to the unit frame so as to be detachable from each other independently; and a lock mechanism having a lock member that restricts movement of the unit frame to one side in the first direction by being held at a first position engageable with the main body frame, and that restricts movement of the unit frame to the other side in the first direction by detaching all the developing cartridges from the unit frame. Thus, the locking member is displaced from the first position to a second position where the locking member is not engaged with the main body frame.

Description

Technical Field

[0001] The present invention relates to an image forming device. Background Art

[0002] A conventional image forming apparatus includes a process unit that is attachable to and detachable from the apparatus body. The process unit includes a developing cartridge for developing a toner image.

[0003] For example, when performing maintenance (e.g., component replacement) on the process unit, the process unit is removed from the device body. Since the process unit is relatively heavy, when removing the process unit from the device body, an operator may accidentally drop the process unit. Summary of the invention

[0004] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus having a structure in which a process unit is attachable to and detachable from a main body of the apparatus and the process unit can be safely removed.

[0005] In order to achieve the above-mentioned object, an image forming device according to one aspect of the present invention comprises: a main frame; and a process unit that performs a development process of developing an electrostatic latent image into a colorant image. The process unit comprises: a unit frame that is detachably mounted relative to the main frame and can be removed by pulling it out from the main frame to one side in a first direction; a plurality of developing cartridges that are detachably mounted relative to the unit frame and each accommodates colorants for the development process; and a locking mechanism that restricts the removal of the unit frame from the main frame. The locking mechanism comprises a locking member that is retained in a first position that can be engaged with the main frame, thereby restricting the movement of the unit frame to one side in the first direction. By removing all the developing cartridges from the unit frame, the locking member is displaced from the first position to a second position that is not engaged with the main frame.

[0006] In the present invention, by providing a structure in which the process unit is attachable to and detachable from the apparatus main body, the process unit can be safely removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view of the image forming apparatus according to the embodiment. Figure 2 yes Figure 1 A perspective view of the image forming apparatus shown in FIG. 1 with its front cover opened. Figure 3 It is a schematic diagram showing the internal structure of the image forming apparatus according to the embodiment. Figure 4 It is a schematic diagram showing an image forming section of the image forming apparatus according to the embodiment. Figure 5 yes Figure 1 A perspective view of the image forming apparatus in a state where a process unit is pulled out is shown. Figure 6 yes Figure 5 Magnified view of the area enclosed by the dotted line. Figure 7 is along with Figure 6 This is a diagram equivalent to the cross section along line A-A'. Figure 8 It is a perspective view of a link member of the image forming apparatus according to the embodiment. Fig. 9 It is a diagram showing an engaging structure between a developing cartridge and a link member in the image forming apparatus according to the embodiment. Fig.10 This is an enlarged view showing a locking member and its surroundings of the image forming apparatus according to the embodiment. Fig.11 It is a diagram showing a state in which all the developing cartridges of the image forming apparatus according to the embodiment are engaged with the link member. Fig.12 It is a diagram showing a state in which the engagement between all the developing cartridges and the link members of the image forming apparatus according to the embodiment is released. Fig.13 It is a diagram showing displacement of the position of the locking member of the image forming apparatus according to the embodiment. DETAILED DESCRIPTION

[0008] Below, refer to Figures 1 to 13 , an image forming apparatus 100 according to an embodiment of the present invention will be described. In the following description, a tandem color laser printer is used as an example, but the present invention is not limited to printers, and can also be applied to multifunction machines having a copying function.

[0009] In the following description, the direction perpendicular to the flat ground on which the image forming apparatus 100 is installed is referred to as the up-down direction. In addition, among the horizontal directions perpendicular to the up-down direction, one direction is denoted by reference numeral D1 and referred to as the first direction D1, and the other direction perpendicular to the one direction is denoted by reference numeral D2 and referred to as the second direction D2. In addition, "horizontal" includes not only completely horizontal but also approximately horizontal.

[0010] For example, the first direction D1 is the front-to-back direction (depth direction) of the image forming apparatus 100. One side of the first direction D1 is the front side, and the other side opposite to the one side of the first direction D1 is the rear side. In addition, the second direction D2 is the left-to-right direction (width direction) of the image forming apparatus 100. One side of the second direction D2 is the left side, and the other side opposite to the one side of the second direction D2 is the right side.

[0011] <Overall Structure of Image Forming Apparatus> The image forming apparatus 100 of this embodiment has Figure 1 and Figure 2 The image forming apparatus 100 has a main frame 1. In addition, the image forming apparatus 100 has a front cover CV. The main frame 1 is covered by an outer decorative cover including the front cover CV (other covers are omitted from the reference numerals). The main frame 1 supports the outer decorative cover. The front cover CV is arranged on one side of the first direction D1. The front cover CV covers the internal area of ​​the image forming apparatus 100 from one side of the first direction D1.

[0012] The main frame 1 supports the front cover CV so that it can rotate around an axis extending in the second direction D2. The front cover CV rotates in a manner that the upper end swings with the lower end as a fulcrum. In other words, the front cover CV is supported so that it can be opened and closed relative to the main frame 1. By opening the front cover CV, the internal area of ​​the image forming device 100 is exposed to one side in the first direction D1 (refer to Figure 2 By closing the front cover CV, the inner area of ​​the image forming apparatus 100 is covered from one side in the first direction D1 (see Figure 1 ).

[0013] like Figure 3 As shown in FIG. 1 , the image forming apparatus 100 includes a main conveying path MP. Figure 3 In FIG. 1 , a main transport path MP is schematically indicated by a solid arrow, and a double-sided printing transport path DP described later is schematically indicated by a dotted arrow.

[0014] The image forming apparatus 100 also includes a sheet cassette CA. The sheet cassette CA stores sheets S used in a printing job. The type of the sheets S is not particularly limited.

[0015] In a printing job, the image forming apparatus 100 supplies the sheet S from the sheet cassette CA to the main conveying path MP and conveys the sheet S along the main conveying path MP. Then, the image forming apparatus 100 prints an image on the conveyed sheet S. In other words, the image forming apparatus 100 transfers a toner image to the conveyed sheet S.

[0016] The sheet cassette CA is installed below the main body of the image forming apparatus 100. The sheet cassette CA is attachable to and detachable from the main body (in other words, the main frame 1) of the image forming apparatus 100. The sheet cassette CA can be removed from the main body by pulling the sheet cassette CA out from the main body toward one side in the first direction D1.

[0017] The image forming apparatus 100 includes image forming units 110 for four colors, cyan, magenta, yellow, and black. Each image forming unit 110 forms a toner image of a corresponding color. Hereinafter, the structure of a certain image forming unit 110 will be described with attention paid to the structure of the image forming unit 110. The basic structures of the image forming units 110 are the same as each other. Therefore, the description of the structures of the other image forming units 110 will be omitted by citing the following description.

[0018] like Figure 4 As shown, the image forming unit 110 includes a developing cartridge 200. The developing cartridge 200 contains toner of corresponding colors and performs a developing process using the toner. In addition, the image forming unit 110 includes a photosensitive drum 111 and a charging device 112. In addition, the image forming unit 110 includes one exposure unit 113 for the image forming unit 110 of four colors. In addition, the image forming unit 110 includes a cleaning device 114.

[0019] When the image forming unit 110 forms an image, the photosensitive drum 111 rotates. The charging device 112 charges the outer peripheral surface of the photosensitive drum 111. The exposure unit 113 exposes the outer peripheral surface of the photosensitive drum 111 to form an electrostatic latent image on the outer peripheral surface of the photosensitive drum 111. Then, as a developing process, the developing box 200 performs a process of supplying toner to the outer peripheral surface of the photosensitive drum 111 and developing the electrostatic latent image into a toner image. In addition, the toner image on the outer peripheral surface of the photosensitive drum 111 is transferred once to the intermediate transfer belt 121 described later. The cleaning device 114 removes the toner that is not transferred to the intermediate transfer belt 121 and remains on the outer peripheral surface of the photosensitive drum 111.

[0020] return Figure 3 The image forming apparatus 100 includes an intermediate transfer unit 120. The intermediate transfer unit 120 is disposed below each image forming section 110. The intermediate transfer unit 120 includes an intermediate transfer belt 121. The intermediate transfer belt 121 is an endless belt.

[0021] The intermediate transfer belt 121 is stretched and stretched by a plurality of rollers including a driving roller 122 (other rollers are not shown in the figure), and is supported by the plurality of rollers so as to be rotatable. The intermediate transfer belt 121 is in contact with the outer peripheral surface of the photosensitive drum 111 and rotates in this state. The driving roller 122 is rotated by the power transmitted from the belt motor (not shown). The intermediate transfer belt 121 is driven to rotate by the rotation of the driving roller 122.

[0022] The intermediate transfer unit 120 includes a primary transfer roller 123. One primary transfer roller 123 is allocated to each color of cyan, magenta, yellow, and black. Each primary transfer roller 123 is arranged on the inner peripheral side of the intermediate transfer belt 121. Each primary transfer roller 123 is arranged opposite to the photosensitive drum 111 of the corresponding color across the intermediate transfer belt 121.

[0023] The intermediate transfer unit 120 includes a secondary transfer roller 124. The secondary transfer roller 124 is pressed against the outer peripheral surface of the intermediate transfer belt 121 and forms a transfer nip with the intermediate transfer belt 121. The main conveying path MP passes through the transfer nip.

[0024] Each image forming unit 110 forms a toner image of a corresponding color. Then, each primary transfer roller 123 primarily transfers the toner image to the outer peripheral surface of the intermediate transfer belt 121. The intermediate transfer belt 121 carries the toner image primarily transferred from each photosensitive drum 111 on the outer peripheral surface and rotates. In the process of the sheet S passing through the transfer nip, the sheet S contacts the outer peripheral surface of the intermediate transfer belt 121. The secondary transfer roller 124 forms a transfer electric field between the intermediate transfer belt 121 and the secondary transfer roller 124, thereby secondary transferring the toner image to the sheet S passing through the transfer nip.

[0025] The image forming apparatus 100 includes a fixing roller pair 130. The fixing roller pair 130 includes a heating roller and a pressure roller. The heating roller has a built-in heater. The pressure roller is pressed against the heating roller and forms a fixing nip between the heating roller and the pressure roller. The fixing roller pair 130 rotates while holding a sheet S conveyed from the transfer nip. That is, the fixing roller pair 130 heats and presses the sheet S passing through the fixing nip. Thus, the fixing roller pair 130 fixes the toner image transferred to the sheet S to the sheet S. Thereafter, the sheet S is discharged to the discharge tray ET.

[0026] As a printing job, the image forming apparatus 100 can perform a single-sided printing job of printing a toner image only on one side of a sheet S, and a double-sided printing job of printing a toner image on both sides of a sheet S. To perform the double-sided printing job, the image forming apparatus 100 includes a double-sided printing conveying path DP.

[0027] The duplex printing conveying path DP branches from the main conveying path MP at a position in the main conveying path MP that is downstream of the fixing nip in the sheet conveying direction, and merges with the main conveying path MP at a position in the main conveying path MP that is upstream of the transfer nip in the sheet conveying direction.

[0028] When the executed job is a single-sided printing job, the sheet S passes through the transfer nip only once, and the transfer process is performed only once on the sheet S passing through the transfer nip. Then, after the first transfer process, the sheet S is directly discharged to the discharge tray ET.

[0029] When the executed job is a double-sided printing job, the sheet S passes through the transfer nip twice because the transfer process is performed once for each of the front and back sides of the sheet S. Specifically, when the sheet S passes through the transfer nip for the first time, the transfer process is performed on one side of the sheet S. After the first transfer process, after the rear end of the sheet S passes through the fixing nip and before the sheet S is completely discharged to the discharge tray ET, the sheet S is switched back. As a result, the sheet S is pulled into the double-sided printing conveying path DP from the rear end.

[0030] Thereafter, the sheet S is conveyed along the double-sided printing conveying path DP. Then, the sheet S returns to the main conveying path MP from a position upstream of the transfer nip in the sheet conveying direction. The sheet S returned to the main conveying path MP passes through the transfer nip again. At this time, the orientation of the front and back sides of the sheet S is reversed to the opposite orientation when it passed through the transfer nip last time. Thus, when the sheet S passes through the transfer nip for the second time, the other side of the sheet S opposite to the one side is subjected to transfer processing.

[0031] <Structure of process unit> The image forming apparatus 100 includes a process unit 2 that performs a development process for developing an electrostatic latent image into a toner image. Specifically, the image forming unit 110 of four colors (i.e., a plurality of colors) is unitized to form the process unit 2. In other words, the process unit 2 includes at least four colors (i.e., a plurality of colors) of developing cartridges 200.

[0032] The process unit 2 has a unit frame 21 (refer to Figure 5 ). The image forming unit 110 of four colors is disposed in the unit frame 21. That is, the developing cartridges 200 of four colors are disposed in the unit frame 21. By arranging the image forming unit 110 of four colors in the unit frame 21, the image forming unit 110 of four colors is unitized.

[0033] The image forming units 110 of four colors are arranged in the first direction D1. That is, the developing cartridges 200 of four colors are arranged in the first direction D1. Therefore, the unit frame 21 has at least a pair of side plates (reference numerals omitted) that clamp the image forming units 110 of four colors in the second direction D2. The pair of side plates of the unit frame 21 rotatably supports each rotating body included in the image forming units 110 of four colors.

[0034] The unit frame 21 is mounted to the main frame 1 in a manner that allows it to be mounted and disassembled in the horizontal direction (specifically, the first direction D1). Thus, the process unit 2 can be mounted and disassembled in the horizontal direction relative to the apparatus main body (i.e., the main frame 1) of the image forming apparatus 100. When performing maintenance on the image forming apparatus 100, the process unit 2 is removed from the apparatus main body. For example, when replacing any one of the developing cartridges 200, the process unit 2 is removed from the apparatus main body.

[0035] In the disassembly operation of the process unit 2, first, the front cover CV is opened in a state where the process unit 2 is installed in the apparatus body of the image forming apparatus 100 (i.e., the unit frame 21 is installed in the main body frame 1). By opening the front cover CV, the front cover CV is opened. Figure 2 That is, the process unit 2 is exposed to one side in the first direction D1. Then, from this state, the unit frame 21 is pulled out to one side in the first direction D1.

[0036] For example, the unit frame 21 has a grip portion 2 a gripped by a worker who is in charge of disassembling the process unit 2 . Figure 5 This shows a state where the process unit 2 is pulled out toward one side in the first direction D1 relative to the main frame 1 .

[0037] By pulling the process unit 2 out relative to the main frame 1, the four-color developer cartridges 200 are exposed upward. The four-color developer cartridges 200 are installed relative to the unit frame 21 in a manner that they can be independently installed and removed. Under this structure, even if one of the developer cartridges 200 is removed from the unit frame 21, the other developer cartridges 200 remain installed on the unit frame 21. That is, in order to remove all the four-color developer cartridges 200 from the unit frame 21, it is necessary to perform the disassembly operation on the four-color developer cartridges 200 separately. The components such as the photosensitive drum 111 other than the developer cartridge 200 in the image forming unit 110 are fixedly installed relative to the unit frame 21 and cannot be removed from the unit frame 21.

[0038] The four color developing cartridges 200 are vertically attachable and detachable relative to the unit frame 21. When the four color developing cartridges 200 are removed from the unit frame 21, the four color developing cartridges 200 are respectively pulled up relative to the unit frame 21. Therefore, the unit frame 21 does not cover the four color developing cartridges 200 from above.

[0039] When the pulling-out amount of the process unit 2 relative to the main frame 1 reaches a predetermined amount, in other words, before the process unit 2 is about to be removed from the main frame 1, the movement of the process unit 2 to one side of the first direction D1 (hereinafter referred to as the pulling-out movement) is locked, and the process unit 2 cannot be further pulled out. After the pulling-out amount of the process unit 2 relative to the main frame 1 reaches a predetermined amount, in order to further pull out the process unit 2 and remove the process unit 2 from the main frame 1, it is necessary to release the lock on the pulling-out movement. In addition, since the state in which the pulling-out movement is locked is a state in which the process unit 2 cannot be removed from the main frame 1, it is equivalent to a state in which the process unit 2 is installed on the main frame 1.

[0040] <Structure of the locking mechanism> Process unit 2 has Figures 5 to 10 The locking mechanism 20 shown. The locking mechanism 20 is a mechanism for limiting the removal of the process unit 2 (i.e., the unit frame 21) from the main frame 1. The locking mechanism 20 is configured on the side plate on one side of the second direction D2 of a pair of side plates of the unit frame 21, and is not configured on the side plate on the other side of the second direction D2. In addition, Figure 6 yes Figure 5 Magnified view of the area enclosed by the dotted line. Figure 7 is along with Figure 6 This is a diagram equivalent to the cross section along line A-A'.

[0041] The locking mechanism 20 includes at least a link member 210, a first biasing member 220, and a locking member 230. The main body engaging portion 10 (see Fig.13 ) can also be said to be a component of the locking mechanism 20.

[0042] like Figure 7 and Figure 8 As shown, the link member 210 is supported relative to the unit frame 21 (specifically, the side plate on one side of the second direction D2) so as to be reciprocating in the first direction D1. The link member 210 changes its position in the first direction D1 according to the attachment and detachment of the four color developing cartridges 200 relative to the unit frame 21.

[0043] Specifically, the link member 210 integrally includes four link engagement portions 211. The four link engagement portions 211 are arranged at intervals from each other in the first direction D1. The four link engagement portions 211 are assigned to different developing cartridges 200.

[0044] The four color developing cartridges 200 have cartridge engaging portions 201 that engage with the assigned link engaging portions 211 (see Fig. 9 Each cartridge engaging portion 201 protrudes in a cylindrical shape toward one side in the second direction D2. Each cartridge engaging portion 201 is a convex portion protruding toward one side in the second direction D2.

[0045] Here, refer to Fig. 9 The engaging structure of a certain developing box 200 (box engaging portion 201) and the connecting rod engaging portion 211 assigned to the developing box 200 is described. Since the engaging structures of the developing boxes 200 of four colors are the same, the engaging structures of the other developing boxes 200 are omitted by citing the following description. In addition, in the drawings referred to in the following description, the connecting rod engaging portion 211 is shaded.

[0046] When the developing box 200 is installed in the unit frame 21, the box engaging portion 201 engages with the connecting rod engaging portion 211 in the first direction D1. At this time, the connecting rod engaging portion 211 is located on one side of the first direction D1 relative to the box engaging portion 201. In other words, the box engaging portion 201 is located on the other side of the first direction D1 relative to the connecting rod engaging portion 211.

[0047] When removing the developing cartridge 200 from the unit frame 21, the developing cartridge 200 is pulled up relative to the unit frame 21. At this time, the cartridge engaging portion 201 moves upward. As a result, the engagement between the cartridge engaging portion 201 and the link engaging portion 211 in the first direction D1 is released. Fig. 9 In FIG. 1 , a moving path of the cartridge engaging portion 201 when the developing cartridge 200 is pulled up relative to the unit frame 21 is indicated by a dotted arrow.

[0048] return Figure 7 and Figure 8 The link member 210 has an end on the other side of the first direction D1 as a link abutment portion 212. The link abutment portion 212 is located at the end on the other side of the first direction D1 in the unit frame 21. The link abutment portion 212 abuts against a portion of the locking member 230 in the up-down direction. In addition, the link abutment portion 212 is the top end on the other side of the first direction D1 in the link member 210.

[0049] like Figure 7 As shown, the first force member 220 is mounted on the unit frame 21. The first force member 220 is, for example, a compression coil spring. The first force member 220 has the first direction D1 as an axial direction. The first force member 220 applies force to the link member 210 toward the other side of the first direction D1. Specifically, the unit frame 21 has a support portion 21a, and the support portion 21a supports the end of the first force member 220 on one side of the first direction D1. The link member 210 has a support portion 210a, and the support portion 210a supports the end of the first force member 220 on the other side of the first direction D1.

[0050] like Figure 7 and Fig.10As shown, the locking member 230 is arranged at the end of the other side of the first direction D1 in the unit frame 21. The locking member 230 has a rotation axis 230A extending in the second direction D2. In addition, the locking member 230 has a first part 231 and a second part 232. The first part 231 is arranged on one side of the first direction D1 relative to the rotation axis 230A, and can rotate with the rotation axis 230A as a fulcrum. The second part 232 is arranged on the other side of the first direction D1 relative to the rotation axis 230A, and can rotate with the rotation axis 230A as a fulcrum. Under this structure, if the position of the first part 231 is displaced upward (i.e., one side in the up-down direction), the position of the second part 232 is displaced downward (i.e., the other side opposite to the one side in the up-down direction).

[0051] The first portion 231 abuts against the link abutment portion 212 in the vertical direction. The link abutment portion 212 abuts against the first portion 231 from above (i.e., one side in the vertical direction). In other words, the first portion 231 abuts against the link abutment portion 212 from below (i.e., the other side opposite to the one side in the vertical direction).

[0052] The second portion 232 can be engaged with the main frame 1 in the first direction D1. The details will be described later, but the main frame 1 has a main body engaging portion 10 (see Fig.13 ). The second portion 232 can be engaged with the main body engaging portion 10 in the first direction D1. When the main body engaging portion 10 is engaged with the second portion 232, the main body engaging portion 10 is located on one side of the first direction D1 relative to the second portion 232. In other words, when the main body engaging portion 10 is engaged with the second portion 232, the second portion 232 is located on the other side of the first direction D1 relative to the main body engaging portion 10.

[0053] In addition, the locking member 230 has a second force applying member 233. The second force applying member 233 is, for example, a tension coil spring. The main frame 1 has a spring support portion 11 that supports the second force applying member 233. The spring support portion 11 is arranged at a position opposite to the second portion 232 in the up-down direction with a gap therebetween. The spring support portion 11 is arranged below the second portion 232. The second force applying member 233 is arranged between the second portion 232 and the spring support portion 11 in the up-down direction. The upper end of the second force applying member 233 is mounted on the second portion 232, and the lower end is mounted on the spring support portion 11. The second force applying member 233 pulls the second portion 232 downward.

[0054] <Restrictions on disassembly of process units> In a state where the unit frame 21 is mounted with the developing cartridges 200 of four colors, as shown in FIG. Fig.11As shown in FIG. 1 , by engaging the developing cartridges 200 (cartridge engaging portion 201) of four colors with the link member 210 (link engaging portion 211) in the first direction D1, the link member 210 is restricted from moving to the other side of the first direction D1. That is, although the link member 210 is urged to the other side of the first direction D1 by the force of the first force applying member 220, it does not move to the other side of the first direction D1. In addition, when all the developing cartridges 200 are removed from the unit frame 21, the force of the first force applying member 220 is utilized, as shown in FIG. Fig.12 As shown in FIG. 1 , the link member 210 moves to the other side of the first direction D1 . The details will be described later.

[0055] Here, the locking member 230 is a member whose position is displaced by the movement of the link member 210 in the first direction D1. That is, if the link member 210 does not move to the other side of the first direction D1, the position of the locking member 230 is fixed.

[0056] Specifically, in a state where the developing cartridges 200 of four colors are mounted on the unit frame 21 , the locking member 230 is held at the first position where it can be engaged with the main body engaging portion 10 in the first direction D1 . Fig.10 The position of the locking member 230 shown is the first position. At this time, the first portion 231 of the locking member 230 abuts against the link abutment portion 212 in the vertical direction. As a result, the upward movement of the first portion 231 is restricted, and the locking member 230 does not displace from the first position.

[0057] exist Fig.10 In the state shown in FIG. 1 , the unit frame 21 is pulled out toward one side of the first direction D1. As a result, as shown in FIG. Fig.13 As shown in the above figure, the second portion 232 of the locking member 230 is engaged with the main body engaging portion 10 in the first direction D1. In this state, the unit frame 21 cannot be further pulled out to one side of the first direction D1. In other words, the locking member 230 restricts the unit frame 21 from moving to one side of the first direction D1.

[0058] If the unit frame 21 is pulled out to Fig.13 In the state shown in the figure above, all the developing boxes 200 are exposed upward (refer to Figure 5 ). Thus, the entire developing cartridge 200 can be removed from the unit frame 21.

[0059] Here, assuming that Fig.13In the state shown in the figure above, for example, one to three developing cartridges 200 are removed from the unit frame 21. However, in this case, the developing cartridges 200 remaining in the unit frame 21 are still engaged with the link member 210 in the first direction D1, so the link member 210 does not move to the other side of the first direction D1, and the locking member 230 is maintained in the first position. That is, the second portion 232 of the locking member 230 and the main body engaging portion 10 are maintained in the engaged state in the first direction D1.

[0060] On the other hand, it is assumed that all the developing cartridges 200 are removed from the unit frame 21. In this case, Fig.12 As shown, the engagement between the link member 210 and all the developing cartridges 200 in the first direction D1 is released, and thus the link member 210 moves to the other side of the first direction D1 by the urging force of the first urging member 220 .

[0061] The link member 210 moves toward the other side of the first direction D1, so that the locking member 230 is displaced from the first position to the second position. Specifically, the link member 210 moves toward the other side of the first direction D1, so that Fig.13 As shown in the figure below, the link contact portion 212 moves to a position where it does not contact the first portion 231 in the vertical direction. At this time, the first portion 231 moves upward, and the second portion 232 moves downward. As a result, the engagement between the main body engaging portion 10 and the second portion 232 in the first direction D1 is released. As a result, the unit frame 21 can be removed from the main frame 1.

[0062] In the present embodiment, if at least one developing cartridge 200 is not removed from the unit frame 21 and remains on the unit frame 21, the unit frame 21 is restricted from being removed from the main frame 1. That is, in a state where at least one developing cartridge 200 is mounted on the unit frame 21, the process unit 2 cannot be removed from the apparatus main body (i.e., the main frame 1) of the image forming apparatus 100. By removing all the developing cartridges 200 from the unit frame 21, the process unit 2 can be removed from the apparatus main body.

[0063] By removing all the developing cartridges 200 from the unit frame 21, the process unit 2 becomes relatively light. When the process unit 2 is light, it is easy to carry the process unit 2. Thus, it is possible to prevent the operator in charge of removing the process unit 2 from accidentally dropping the process unit 2. That is, the process unit 2 can be safely removed.

[0064] Furthermore, in the present embodiment, by utilizing the lock mechanism 20 , it is possible to easily obtain a structure in which the process unit 2 can be removed from the apparatus main body only when all the developing cartridges 200 are removed from the unit frame 21 .

[0065] It should be understood that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is not indicated by the description of the above embodiments but by the claims, and includes the meaning equivalent to the claims and all changes within the scope of the claims.

Claims

1. An image forming device, characterized in that: have: Main frame; as well as The process unit performs a developing process of developing the electrostatic latent image into a toner image, The process unit has: a unit frame, which is detachably mounted relative to the main frame and can be removed by pulling it out from the main frame toward one side in a first direction; A plurality of developing cartridges are mounted to the unit frame in an independently attachable and detachable manner and respectively contain toner for the developing process; as well as a locking mechanism that restricts removal of the unit frame from the main frame, The locking mechanism includes a locking member, and the locking member is held in a first position capable of engaging with the main frame, thereby restricting the movement of the unit frame to one side in the first direction. By removing all of the developing cartridges from the unit frame, the locking member is displaced from the first position to a second position where the locking member is not engaged with the main body frame.

2. The image forming apparatus according to claim 1, wherein: The locking mechanism also has: a link member reciprocatably movable in the first direction relative to the unit frame; and a first force applying member, applying force to the link member toward the other side of the first direction; The locking member is a member whose position is displaced by the movement of the link member in the first direction. The plurality of developing cartridges are respectively engaged with the link member in a state of being mounted on the unit frame, thereby restricting the link member from moving to the other side of the first direction. By removing all of the developing cartridges from the unit frame, the link member is moved to the other side of the first direction by the urging force of the urging member. The locking member is displaced from the first position to the second position by the link member moving to the other side of the first direction.

3. The image forming apparatus according to claim 2, wherein: The link member has a link abutment portion, The locking member has: a rotation axis extending in a second direction orthogonal to the first direction; The first part is arranged at one side of the first direction relative to the rotation axis and can rotate with the rotation axis as a fulcrum so as to be abutted by the connecting rod abutment portion from above; The second part is arranged on the other side of the first direction relative to the rotation axis, can rotate with the rotation axis as a fulcrum, and is held in a position capable of engaging with the main frame when the link abutment portion abuts against the first part; as well as A second force applying member applies force downward to the second portion, When the link member moves to the other side in the first direction, the link contact portion releases contact with the first portion, whereby the second portion moves downward by the biasing force of the second biasing member, and the lock member is displaced from the first position to the second position.

Images