Image forming apparatus

Abstract

To provide an image forming apparatus that allows safe removal of a process unit.SOLUTION: An image forming apparatus comprises a main body frame and a process unit. The process unit has: a unit frame that can be removed from the main body frame by being withdrawn to one side in a first direction; a plurality of developing cartridges that are removably mounted on the unit frame independent of each other; and a lock mechanism. The lock mechanism has a lock member that is held at a first position where it can be engaged with the main body frame to regulate the movement of the unit frame to the one side in the first direction. Upon removal of all the developing cartridges from the unit frame, the lock member is displaced from the first position to a second position where it is not engaged with the main body frame.SELECTED DRAWING: Figure 13

Description

[Technical field]

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

[0002] A conventional image forming apparatus includes a process unit that is detachable from a main body of the apparatus. The process unit includes a developing cartridge for developing a toner image, etc. Such an image forming apparatus is disclosed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-47324 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when performing maintenance on the process unit (e.g., replacing parts), the process unit is removed from the main body of the apparatus. Since the process unit is relatively heavy, when removing the process unit from the main body of the apparatus, an operator may accidentally drop the process unit.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide an image forming apparatus that has a process unit that is detachable from the device main body, and that allows the process unit to be safely removed. [Means for solving the problem]

[0006] In order to achieve the above object, an image forming apparatus according to one aspect of the present invention includes a main body frame and a process unit that executes a development process for developing an electrostatic latent image into a toner image. The process unit includes a unit frame that is detachably attached to the main body frame and can be removed by pulling it out from the main body frame to one side in a first direction, a plurality of developer cartridges that are detachably attached to the unit frame independently of one another and each of which contains toner for the development process, and a locking mechanism that restricts removal of the unit frame from the main body frame. The locking mechanism has a locking member that is held at a first position where it can engage with the main body frame, thereby restricting movement of the unit frame to one side in the first direction. When all of the developer cartridges are removed from the unit frame, the locking member is displaced from the first position to a second position where it does not engage with the main body frame. Effect of the Invention

[0007] According to the present invention, in a configuration in which a process unit that is detachable from the main body of an apparatus is provided, the process unit can be safely removed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of an image forming apparatus according to an embodiment. [Diagram 2] 2 is a perspective view of the image forming apparatus shown in FIG. 1 with a front cover open. [Diagram 3] 1 is a schematic diagram illustrating an internal configuration of an image forming apparatus according to an embodiment. [Figure 4] 1 is a schematic diagram illustrating an image forming unit of an image forming apparatus according to an embodiment; [Diagram 5] 2 is a perspective view of the image forming apparatus shown in FIG. 1 in a state where a process unit is pulled out. [Figure 6] FIG. 6 is an enlarged view of the area enclosed by the dashed line in FIG. 5. [Figure 7] 7 is a cross-sectional view taken along line AA' in FIG. 6. [Figure 8]FIG. 2 is a perspective view of a link member of the image forming apparatus according to the embodiment. [Figure 9] 5A and 5B are diagrams illustrating an engagement structure between a developing cartridge and a link member of an image forming apparatus according to an embodiment. [Figure 10] 2 is an enlarged view showing a locking member and its periphery in the image forming apparatus according to the embodiment; [Figure 11] 13 is a diagram showing a state in which all of the developing cartridges and the link members of the image forming apparatus according to the embodiment are engaged with each other; FIG. [Figure 12] 13 is a diagram showing a state in which all of the developing cartridges and the link members of the image forming apparatus according to the embodiment are disengaged from each other. FIG. [Figure 13] 6A and 6B are diagrams illustrating positional displacement of a locking member of the image forming apparatus according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An image forming apparatus 100 according to an embodiment of the present invention will be described below with reference to Figures 1 to 13. In the following description, a tandem color laser printer will be used as an example, but the present invention is not limited to printers and can also be applied to multifunction machines having functions such as copying.

[0010] In the following description, the direction perpendicular to the flat floor surface on which the image forming apparatus 100 is installed is defined as the up-down direction. Of the horizontal directions perpendicular to the up-down direction, one direction is given the symbol D1 and referred to as the first direction D1, and the other direction perpendicular to the one direction is given the symbol D2 and referred to as the second direction D2. Note that "horizontal" includes not only completely horizontal, but also approximately horizontal.

[0011] For example, the first direction D1 is the front-to-rear 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. Moreover, 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.

[0012] <Overall configuration of image forming apparatus> Image forming apparatus 100 of this embodiment has an appearance as shown in Fig. 1 and Fig. 2. Image forming apparatus 100 includes a main body frame 1. Image forming apparatus 100 also includes a front cover CV. The main body frame 1 is covered with an exterior cover including the front cover CV (reference numbers for other covers are omitted). The main body frame 1 supports the exterior cover. The front cover CV is disposed on one side in a first direction D1. The front cover CV covers the internal area of ​​image forming apparatus 100 from one side in the first direction D1.

[0013] The main body frame 1 supports the front cover CV rotatably about an axis extending in the second direction D2. The front cover CV rotates around its lower end as a fulcrum, swinging its upper end. In other words, the front cover CV is supported so as to be openable and closable with respect to the main body frame 1. When the front cover CV is opened, the internal area of ​​the image forming device 100 is exposed to one side in the first direction D1 (see FIG. 2). When the front cover CV is closed, the internal area of ​​the image forming device 100 is covered from one side in the first direction D1 (see FIG. 1).

[0014] The image forming apparatus 100 includes a main transport path MP, as shown in Fig. 3. In Fig. 3, the main transport path MP is indicated typically by a solid arrow, and a double-sided printing transport path DP, which will be described later, is indicated typically by a dashed arrow.

[0015] The image forming apparatus 100 also includes a sheet cassette CA. The sheet cassette CA stores sheets S to be used in a print job. The type of the sheets S is not particularly limited.

[0016] In a print job, the image forming apparatus 100 supplies a sheet S from a sheet cassette CA to a main transport path MP and transports the sheet S along the main transport path MP. Then, the image forming apparatus 100 prints an image on the sheet S being transported. In other words, the image forming apparatus 100 transfers a toner image onto the sheet S being transported.

[0017] The sheet cassette CA is attached to the lower part of the main body of the image forming apparatus 100. The sheet cassette CA is detachable from the main body (in other words, the main body 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 to one side in the first direction D1.

[0018] 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 the corresponding color. The configuration of one image forming unit 110 will be described below. The basic configuration of each image forming unit 110 is the same. Therefore, the description of the configuration of the other image forming units 110 will be omitted as the following description is used as a reference.

[0019] As shown in Fig. 4, the image forming unit 110 includes a developing cartridge 200. The developing cartridge 200 contains toner of a corresponding color and executes a developing process using the toner. The image forming unit 110 also includes a photoconductor drum 111 and a charging device 112. The image forming apparatus 100 also includes one exposure unit 113 for each of the image forming units 110 for four colors. The image forming unit 110 also includes a cleaning device 114.

[0020] 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 light, and forms an electrostatic latent image on the outer peripheral surface of the photosensitive drum 111. The developing cartridge 200 then supplies toner to the outer peripheral surface of the photosensitive drum 111 as a developing process, and executes a process of developing the electrostatic latent image into a toner image. The toner image on the outer peripheral surface of the photosensitive drum 111 is primarily transferred to an intermediate transfer belt 121, which will be described later. The cleaning device 114 removes toner that has not been transferred to the intermediate transfer belt 121 and remains on the outer peripheral surface of the photosensitive drum 111.

[0021] Returning to Fig. 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.

[0022] The intermediate transfer belt 121 is stretched and rotatably supported by a plurality of rollers including a drive roller 122 (reference numbers for the other rollers are omitted). The intermediate transfer belt 121 contacts the outer circumferential surface of the photoconductor drum 111 and rotates in this state. The drive roller 122 is rotated by power transmitted from a belt motor (not shown). The intermediate transfer belt 121 is rotated by being driven by the rotation of the drive roller 122.

[0023] The intermediate transfer unit 120 includes primary transfer rollers 123. One primary transfer roller 123 is assigned to each of the colors cyan, magenta, yellow, and black. Each primary transfer roller 123 is disposed on the inner circumferential side of the intermediate transfer belt 121. Each primary transfer roller 123 is disposed opposite the photoconductor drum 111 of the corresponding color, with the intermediate transfer belt 121 sandwiched therebetween.

[0024] The intermediate transfer unit 120 includes a secondary transfer roller 124. The secondary transfer roller 124 is in pressure contact with the outer circumferential surface of the intermediate transfer belt 121, and forms a transfer nip between the secondary transfer roller 124 and the intermediate transfer belt 121. The main transport path MP passes through the transfer nip.

[0025] Each image forming unit 110 forms a toner image of a corresponding color. Then, each primary transfer roller 123 primarily transfers the toner image onto the outer circumferential surface of the intermediate transfer belt 121. The intermediate transfer belt 121 rotates while carrying the toner image primarily transferred from each photoconductor drum 111 on its outer circumferential surface. While the sheet S is passing through the transfer nip, the sheet S comes into contact with the outer circumferential surface of the intermediate transfer belt 121. The secondary transfer roller 124 forms a transfer electric field between itself and the intermediate transfer belt 121, thereby secondary transferring the toner image onto the sheet S passing through the transfer nip.

[0026] 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 in pressure contact with the heating roller to form a fixing nip between the heating roller and the fixing roller pair 130. The fixing roller pair 130 nips the sheet S conveyed from the transfer nip and rotates. That is, the fixing roller pair 130 applies heat and pressure to the sheet S passing through the fixing nip. As a result, the fixing roller pair 130 fixes the toner image transferred to the sheet S to the sheet S. The sheet S is then discharged to the discharge tray ET.

[0027] The image forming apparatus 100 is capable of executing, as a print job, a single-sided print job in which a toner image is printed on only one side of a sheet S, as well as a double-sided print job in which a toner image is printed on both sides of a sheet S. To execute a double-sided print job, the image forming apparatus 100 is provided with a double-sided printing transport path DP.

[0028] The double-sided printing transport path DP branches off from the main transport path MP downstream of the fixing nip in the sheet transport direction, and merges with the main transport path MP upstream of the transfer nip in the sheet transport direction.

[0029] When the job to be executed is a single-sided print job, the sheet S passes through the transfer nip only once, and a single transfer process is performed on the sheet S while it is passing through the transfer nip. After the first transfer process, the sheet S is discharged directly onto the discharge tray ET.

[0030] When the job to be executed is a double-sided printing job, the sheet S passes through the transfer nip twice in order to perform the transfer process once on 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, the sheet S is switched back after the rear end of the sheet S has passed through the fixing nip and before the sheet S is completely discharged onto the discharge tray ET. As a result, the rear end of the sheet S is drawn into the double-sided printing transport path DP.

[0031] Thereafter, the sheet S is transported along the double-sided printing transport path DP. The sheet S is then returned to the main transport path MP from the upstream side of the transfer nip in the sheet transport direction. The sheet S returned to the main transport path MP passes through the transfer nip again. At this time, the orientation of the front and back surfaces of the sheet S is inverted to the opposite orientation from when it passed through the transfer nip the previous time. As a result, when the sheet S passes through the transfer nip for the second time, a transfer process is performed on the other side of the sheet S that is opposite to the one side.

[0032] <Process unit configuration> The image forming apparatus 100 includes a process unit 2 that executes a developing process for developing an electrostatic latent image into a toner image. Specifically, image forming sections 110 for four colors (i.e., a plurality of images) are unitized to form the process unit 2. In other words, the process unit 2 includes at least developing cartridges 200 for four colors (i.e., a plurality of images).

[0033] The process unit 2 has a unit frame 21 (see FIG. 5). Image forming units 110 for four colors are arranged in the unit frame 21. That is, developing cartridges 200 for four colors are arranged in the unit frame 21. By arranging the image forming units 110 for four colors in the unit frame 21, the image forming units 110 for four colors are unitized.

[0034] The image forming units 110 for four colors are arranged in the first direction D1. That is, the developing cartridges 200 for four colors are arranged in the first direction D1. The unit frame 21 has at least a pair of side plates (reference numbers omitted) that sandwich the image forming units 110 for four colors in the second direction D2. The pair of side plates of the unit frame 21 rotatably support each of the rotating bodies included in the image forming units 110 for four colors.

[0035] The unit frame 21 is detachably mounted in the horizontal direction (specifically, the first direction D1) to the main body frame 1. This allows the process unit 2 to be detachably mounted in the horizontal direction to the main body of the image forming apparatus 100 (i.e., the main body frame 1). When performing maintenance on the image forming apparatus 100, the process unit 2 is removed from the main body. For example, when replacing any of the developing cartridges 200, the process unit 2 is removed from the main body.

[0036] In removing the process unit 2, first, the front cover CV is opened with the process unit 2 attached to the device body of the image forming apparatus 100 (i.e., with the unit frame 21 attached to the body frame 1). Opening the front cover CV results in the state shown in FIG. 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.

[0037] For example, the unit frame 21 has a grip portion 2a that is gripped by a worker who is responsible for removing the process unit 2. A state in which the process unit 2 is pulled out to one side in the first direction D1 relative to the main body frame 1 is shown in FIG.

[0038] By drawing out the process unit 2 from the main body frame 1, the developer cartridges 200 for four colors are exposed upward. The developer cartridges 200 for four colors are detachably mounted to the unit frame 21 independently of one another. In this configuration, even if a certain developer cartridge 200 is removed from the unit frame 21, the other developer cartridges 200 remain mounted to the unit frame 21. In other words, to remove all of the developer cartridges 200 for four colors from the unit frame 21, it is necessary to perform the removal work for each of the developer cartridges 200 for four colors. Constituent elements of the image forming section 110 other than the developer cartridges 200, such as the photosensitive drum 111, are fixedly mounted to the unit frame 21 and cannot be removed from the unit frame 21.

[0039] The developer cartridges 200 for four colors are vertically detachable from the unit frame 21. When removed from the unit frame 21, the developer cartridges 200 for four colors are each pulled up relative to the unit frame 21. For this reason, the unit frame 21 does not cover the developer cartridges 200 for four colors from above.

[0040] When the amount by which the process unit 2 has been pulled out from the main body frame 1 reaches a predetermined amount, in other words, immediately before the process unit 2 is to be removed from the main body frame 1, the movement of the process unit 2 in one direction D1 (herein simply referred to as pull-out movement) is locked, and the process unit 2 cannot be pulled out any further. After the amount by which the process unit 2 has been pulled out from the main body frame 1 reaches a predetermined amount, in order to pull the process unit 2 out further and remove the process unit 2 from the main body frame 1, it is necessary to release the lock against pull-out movement. Note that the state in which the pull-out movement is locked corresponds to a state in which the process unit 2 cannot be removed from the main body frame 1, and thus corresponds to a state in which the process unit 2 is attached to the main body frame 1.

[0041] <Lock mechanism configuration> The process unit 2 has a locking mechanism 20 as shown in Figs. 5 to 10. The locking mechanism 20 is a mechanism that restricts removal of the process unit 2 (i.e., the unit frame 21) from the main body frame 1. Of a pair of side plates of the unit frame 21, the locking mechanism 20 is disposed on one side plate in the second direction D2, and is not disposed on the other side plate in the second direction D2. Fig. 6 is an enlarged view of the area surrounded by a dashed line in Fig. 5. Fig. 7 is a view corresponding to a cross section taken along line AA' in Fig. 6.

[0042] The lock mechanism 20 has at least a link member 210, a first biasing member 220, and a lock member 230. It can be said that a main body engaging portion 10 (see FIG. 13), which will be described later, is also one of the components of the lock mechanism 20.

[0043] 7 and 8, the link member 210 is supported by the unit frame 21 (specifically, a side plate on one side in the second direction D2) so as to be reciprocatable in the first direction D1. The link member 210 displaces its position in the first direction D1 in response to the attachment and detachment of the developer cartridges 200 for four colors to and from the unit frame 21.

[0044] Specifically, the link member 210 integrally has four link engagement portions 211. The four link engagement portions 211 are disposed at intervals from one another in the first direction D1. The four link engagement portions 211 are assigned to different developer cartridges 200.

[0045] The four color developer cartridges 200 have cartridge engaging portions 201 (see FIG. 9) that engage with the assigned link engaging portions 211. 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 boss portion that protrudes toward one side in the second direction D2.

[0046] Here, the engagement structure between a certain developer cartridge 200 (cartridge engagement portion 201) and the associated link engagement portion 211 will be described with reference to Fig. 9. Since the engagement structures of the developer cartridges 200 for four colors are the same, the engagement structures of the other developer cartridges 200 will be omitted as the following description is incorporated herein. Note that in the drawings referred to in the following description, the link engagement portion 211 is hatched.

[0047] When the developing cartridge 200 is attached to the unit frame 21, the cartridge engaging portion 201 and the link engaging portion 211 engage with each other in the first direction D1. At this time, the link engaging portion 211 is located on one side of the cartridge engaging portion 201 in the first direction D1. In other words, the cartridge engaging portion 201 is located on the other side of the link engaging portion 211 in the first direction D1.

[0048] When removing the developer cartridge 200 from the unit frame 21, the developer cartridge 200 is pulled up relative to the unit frame 21. At this time, the cartridge engagement portion 201 moves upward. This releases the engagement between the cartridge engagement portion 201 and the link engagement portion 211 in the first direction D1. In Figure 9, the moving path of the cartridge engagement portion 201 when the developer cartridge 200 is pulled up relative to the unit frame 21 is indicated by a dashed arrow.

[0049] 7 and 8, the link member 210 has an end portion on the other side in the first direction D1 as a link abutment portion 212. The link abutment portion 212 is located at an end portion of the unit frame 21 on the other side in the first direction D1. The link abutment portion 212 abuts against a part of the locking member 230 in the up-down direction. The link abutment portion 212 is the tip of the link member 210 on the other side in the first direction D1.

[0050] The first biasing member 220 is attached to the unit frame 21 as shown in FIG. 7. The first biasing member 220 is, for example, a compression coil spring. The first biasing member 220 has an axial direction in the first direction D1. The first biasing member 220 biases the link member 210 to the other side of the first direction D1. Specifically, the unit frame 21 has a support portion 21a that supports an end portion of the first biasing member 220 on one side in the first direction D1. The link member 210 has a support portion 210a that supports an end portion of the first biasing member 220 on the other side in the first direction D1.

[0051] As shown in FIG. 7 and FIG. 10, the locking member 230 is disposed at the end of the unit frame 21 on the other side in the first direction D1. The locking member 230 has a rotation shaft 230A extending in the second direction D2. The locking member 230 also has a first portion 231 and a second portion 232. The first portion 231 is disposed on one side of the rotation shaft 230A in the first direction D1 and is rotatable around the rotation shaft 230A as a fulcrum. The second portion 232 is disposed on the other side of the rotation shaft 230A in the first direction D1 and is rotatable around the rotation shaft 230A as a fulcrum. In this configuration, when the position of the first portion 231 is displaced upward (i.e., one side in the vertical direction), the position of the second portion 232 is displaced downward (i.e., the other side opposite to the one side in the vertical direction).

[0052] The first portion 231 abuts against the link abutment portion 212 in the up-down direction. The link abutment portion 212 abuts against the first portion 231 from above (i.e., one side in the up-down 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 up-down direction).

[0053] The second portion 232 is engageable with the main body frame 1 in the first direction D1. The main body frame 1 has a main body engagement portion 10 (see FIG. 13), which will be described in detail later. The second portion 232 is engageable with the main body engagement portion 10 in the first direction D1. When the main body engagement portion 10 is engaged with the second portion 232, the main body engagement portion 10 is located on one side of the second portion 232 in the first direction D1. In other words, when the main body engagement portion 10 is engaged with the second portion 232, the second portion 232 is located on the other side of the first direction D1 with respect to the main body engagement portion 10.

[0054] The lock member 230 also has a second biasing member 233. The second biasing member 233 is, for example, a tension coil spring. The main body frame 1 has a spring support portion 11 that supports the second biasing member 233. The spring support portion 11 is disposed at a position facing the second portion 232 with a gap therebetween in the vertical direction. The spring support portion 11 is disposed below the second portion 232. The second biasing member 233 is disposed between the second portion 232 and the spring support portion 11 in the vertical direction. An upper end of the second biasing member 233 is attached to the second portion 232, and a lower end is attached to the spring support portion 11. The second biasing member 233 pulls the second portion 232 downward.

[0055] <Process unit removal restrictions> In a state in which the four color developer cartridges 200 are attached to the unit frame 21, as shown in FIG. 11, the four color developer cartridges 200 (cartridge engagement portion 201) are engaged with the link member 210 (link engagement portion 211) in the first direction D1, thereby restricting the movement of the link member 210 to the other side in the first direction D1. That is, the link member 210 is biased to the other side in the first direction D1 by the biasing force of the first biasing member 220, but does not move to the other side in the first direction D1. Note that, when all the developer cartridges 200 are removed from the unit frame 21, the link member 210 moves to the other side in the first direction D1 by the biasing force of the first biasing member 220, as shown in FIG. 12. Details will be described later.

[0056] Here, the locking member 230 is a member whose position is displaced by the movement of the linking member 210 in the first direction D1. In other words, if the linking member 210 does not move to the other side in the first direction D1, the position of the locking member 230 is constant.

[0057] Specifically, when the four color developer cartridges 200 are attached to the unit frame 21, the locking member 230 is held in a first position where it can engage with the main body engaging portion 10 in the first direction D1. The position of the locking member 230 shown in FIG. 10 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 up-down direction. This restricts the upward movement of the first portion 231, and the locking member 230 is not displaced from the first position.

[0058] In the state shown in Fig. 10, the unit frame 21 is pulled out to one side in the first direction D1. As a result, as shown in the upper diagram of Fig. 13, the second portion 232 of the locking member 230 and the main body engaging portion 10 engage in the first direction D1. In this state, the unit frame 21 cannot be pulled out further to one side in the first direction D1. In other words, the locking member 230 restricts the movement of the unit frame 21 to one side in the first direction D1.

[0059] 13, all of the developing cartridges 200 are exposed upward (see FIG. 5). This makes it possible to remove all of the developing cartridges 200 from the unit frame 21.

[0060] 13, for example, one to three developer cartridges 200 are removed from the unit frame 21. However, in this case, the developer 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 in the first direction D1, and the lock member 230 is held in the first position. In other words, the second part 232 of the lock member 230 and the main body engaging portion 10 are held in a state of being engaged with each other in the first direction D1.

[0061] On the other hand, suppose that all of the developing cartridges 200 are removed from the unit frame 21. In this case, as shown in Fig. 12, the link member 210 is disengaged from all of the developing cartridges 200 in the first direction D1, and moves to the other side in the first direction D1 by the biasing force of the first biasing member 220.

[0062] As the link member 210 moves to the other side in the first direction D1, the lock member 230 is displaced from the first position to the second position. Specifically, as the link member 210 moves to the other side in the first direction D1, the link abutment portion 212 moves to a position where it does not contact the first portion 231 in the up-down direction, as shown in the lower diagram of FIG. 13. At this time, the first portion 231 moves upward, and the second portion 232 moves downward. This releases the engagement between the main body engagement portion 10 and the second portion 232 in the first direction D1. As a result, it becomes possible to remove the unit frame 21 from the main body frame 1.

[0063] In this embodiment, if at least one developing cartridge 200 remains unremoved from the unit frame 21, removal of the unit frame 21 from the main body frame 1 is restricted. In other words, in a state where at least one developing cartridge 200 is attached to the unit frame 21, the process unit 2 cannot be removed from the device main body of the image forming apparatus 100 (i.e., the main body frame 1). When all the developing cartridges 200 are removed from the unit frame 21, the process unit 2 can be removed from the device main body.

[0064] By removing all of the developing cartridges 200 from the unit frame 21, the process unit 2 becomes relatively light. When the process unit 2 is light, it becomes easy to carry the process unit 2. This prevents the worker in charge of removing the process unit 2 from accidentally dropping the process unit 2. In other words, the process unit 2 can be removed safely.

[0065] In addition, in this embodiment, by using the locking mechanism 20, it is possible to easily obtain a configuration in which the process unit 2 can be removed from the apparatus main body only when all of the developing cartridges 200 have been removed from the unit frame 21.

[0066] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0067] 1 Main frame 2 Process Unit 20 Locking mechanism 21 Unit Frame 100 Image forming device 200 Developer Cartridge 210 Link member 212 Link abutment 220 First biasing member 230 Locking member 230A Rotating shaft 231 Part 1 232 Part 2 233 Second biasing member D1 1st direction D2 2nd direction

Claims

1. A body frame, a process unit that executes a developing process for developing the electrostatic latent image into a toner image; The process unit includes: a unit frame that is detachably attached to the main body frame and can be removed by pulling it out from the main body frame to one side in a first direction; a plurality of developing cartridges that are independently and detachably mounted on the unit frame, each of which contains a toner for the developing process; a lock mechanism that restricts removal of the unit frame from the main body frame, the locking mechanism has a locking member that is held at a first position engageable with the main body frame to restrict movement of the unit frame to one side in the first direction, the locking member is displaced from the first position to a second position where it does not engage with the main body frame when all of the developing cartridges are removed from the unit frame.

2. The locking mechanism includes: a link member reciprocally movable in the first direction relative to the unit frame; a first biasing member that biases the link member to the other side in the first direction, the locking member is a member whose position is displaced by the movement of the link member in the first direction, When the developing cartridges are attached to the unit frame, the developing cartridges engage with the link member to restrict movement of the link member to the other side in the first direction, When all of the developing cartridges are removed from the unit frame, the link member is moved to the other side in the first direction by the biasing force of the biasing member, The image forming apparatus according to claim 1 , wherein the locking member is displaced from the first position to the second position by the link member moving to the other side in the first direction.

3. The link member has a link abutment portion, The locking member is A rotation axis extending in a second direction perpendicular to the first direction; a first portion that is disposed on one side of the rotation shaft in the first direction, that is rotatable about the rotation shaft as a fulcrum, and that the link abutment portion abuts against from above; a second portion that is disposed on the other side of the pivot shaft in the first direction, is rotatable about the pivot shaft, and is held at a position where it can engage with the main body frame when the link abutment portion abuts against the first portion; a second biasing member that biases the second portion downward, 3. The image forming apparatus according to claim 2, wherein when the link member moves to the other side in the first direction, the link abutment portion is released from contact with the first portion, so that the second portion moves downward due to the biasing force of the second biasing member, and the locking member is displaced from the first position to the second position.

Images