JP2023173211A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that not only allows an operator to stably hold an image forming unit removed from an apparatus body but to prevent damage to an image carrier.SOLUTION: An image forming apparatus has a housing Cs composed of a top wall Wt and walls, an apparatus body formed in the housing Cs, and an image forming unit 20 removably disposed to the apparatus body. Engagement parts are formed at predetermined portions of the image forming unit 20, parts to be engaged are formed at predetermined portions of the top wall Wt, and the engagement parts and the parts to be engaged are engaged with each other to lock the image forming unit 20 to the housing Cs. In carrying out maintenance of the image forming apparatus, and in performing operation to remove a medium that has caused medium jam, an operator does not need to secure a place for placing the image forming unit 20. The operator can prevent damage to an image carrier. The operator can suppress the image carrier from receiving light and can thus suppress deterioration of the image carrier.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus.

Conventionally, image forming apparatuses such as printers, copying machines, facsimile machines, and multifunction devices, such as printers, include an image forming section in which an image forming unit, an LED head, a transfer roller, etc. are disposed. It has become. In the image forming unit, the surface of the photosensitive drum as an image carrier charged by the charging roller is exposed to light by the LED head to form an electrostatic latent image, and the electrostatic latent image is developed. A toner image is formed on the photoreceptor drum.

Further, in the printer, paper fed from a paper cassette is conveyed through a paper transport path and supplied to an image forming section, and the toner image is transferred onto the paper by the transfer roller in the image forming section, and a fixing device It is fixed on the paper in the process.

Incidentally, in the printer, the image forming unit is removably installed in the main body of the printer, that is, the main body of the device, and the operator can perform maintenance on the printer or while the paper is being transported along the paper transport path. The image forming unit can be removed when removing paper that has caused a paper jam (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2015-148764

However, in the conventional printers, when an operator performs maintenance on the printer or removes paper that has caused a paper jam, the image forming unit that has been removed from the main body of the printer is temporarily removed. It is necessary to secure a place to place it.

If there is no place to place the image forming unit around the printer, the operator must place the image forming unit at a place away from the printer, which is a cumbersome task. Further, if the place where the image forming unit is placed is not flat, the image forming unit cannot be placed stably, and the photosensitive drum may be damaged by being hit by foreign objects.

The present invention solves the problems of conventional printers and makes it possible to not only stably hold the image forming unit removed from the apparatus main body, but also to prevent the image bearing member from being damaged. The purpose is to provide equipment.

For this purpose, the image forming apparatus of the present invention includes a casing including a top wall and a wall extending in the vertical direction and having a flat wall surface, an apparatus main body formed within the casing, and a main body of the apparatus. and an image forming unit that is removably installed.

An engaging portion is formed at a predetermined location of the image forming unit.

Furthermore, an engaged portion is formed at a predetermined location on the top wall.

Then, by engaging the engaging portion and the engaged portion, the image forming unit is locked to the housing.

According to the present invention, an image forming apparatus includes a casing including a top wall and a wall extending in a vertical direction and having a flat wall surface; and an image forming unit that is removably installed.

An engaging portion is formed at a predetermined location of the image forming unit.

Furthermore, an engaged portion is formed at a predetermined location on the top wall.

Then, by engaging the engaging portion and the engaged portion, the image forming unit is locked to the housing.

In this case, an engaging portion is formed at a predetermined location on the image forming unit, an engaged portion is formed at a predetermined location on the top wall of the casing, and the engaging portion and the engaged portion are engaged with each other. As a result, the image forming unit is locked to the casing, so when performing maintenance on the image forming apparatus or removing a medium that has caused a media jam, the image forming unit can be removed from the main body of the apparatus. There is no need to secure a place to place the forming unit.

Furthermore, since the image forming unit can be stabilized and locked to the housing, it is possible to prevent the image carrier from being damaged by being hit by foreign objects.

Furthermore, since the image bearing member is surrounded by the image forming unit while the image forming unit is locked in the housing, it is possible to suppress the image bearing member from receiving light. Therefore, deterioration of the image carrier can be suppressed.

1 is an enlarged view of the main parts of a printer showing a state in which an image forming unit according to an embodiment of the present invention is locked to a housing; FIG. 1 is a conceptual diagram of a printer in an embodiment of the present invention. FIG. 2 is a perspective view showing the state of the printer when the front cover is opened in the embodiment of the present invention. 1 is a perspective view of a printer showing a state in which an image forming unit according to an embodiment of the present invention is removed from an apparatus main body; FIG. FIG. 2 is an enlarged view of the main parts of the printer showing a state in which the image forming unit according to the embodiment of the present invention is removed from the apparatus main body. FIG. 1 is a perspective view of an image forming unit in an embodiment of the present invention. 1 is a sectional view of an image forming unit in an embodiment of the present invention. FIG. 1 is a plan view of an image forming unit in an embodiment of the present invention. It is a bottom surface of the image forming unit in embodiment of this invention. FIG. 3 is a diagram for explaining a procedure for locking an image forming unit to a housing in an embodiment of the present invention. 1 is a perspective view of a printer showing a state in which an image forming unit according to an embodiment of the present invention is locked to a housing; FIG. FIG. 3 is a conceptual diagram for explaining a method of setting the length of the front support leg of the image forming unit in the embodiment of the present invention. It is a figure which shows the state which engaged the hook-shaped leg and the engagement hole in embodiment of this invention. FIG. 3 is a diagram showing a first example of a state in which an image forming unit according to an embodiment of the present invention is attached to an apparatus main body. FIG. 7 is a diagram showing a second example of a state in which the image forming unit according to the embodiment of the present invention is attached to the apparatus main body.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a printer as an image forming apparatus will be described.

FIG. 2 is a conceptual diagram of the printer according to the embodiment of the present invention, and FIG. 3 is a perspective view showing the state of the printer when the front cover is opened according to the embodiment of the present invention. In the figure, the positive direction of the X-axis is the rear direction of the printer 10, the negative direction of the X-axis is the front direction of the printer 10, the positive direction of the Y-axis is the left direction of the printer 10, and the negative direction of the Y-axis is the direction of the printer 10. 10, the Z-axis positive direction is the upward direction in the printer 10, and the Z-axis negative direction is the downward direction in the printer 10.

In the figure, 10 is a printer, Bd is a main body of the printer 10, that is, a main body, and Cs is a casing that surrounds the main body Bd as an exterior of the printer 10. The casing Cs includes a front wall Wf as a first wall, a back wall Wr as a second wall, a third wall disposed on the left side when viewed from the front of the front wall Wf, and a third wall Wf as a first wall. 1, a right side wall Ws2 as a fourth wall disposed on the right side when viewed from the front of the front wall Wf and as a second side wall, and a top wall as a fifth wall. Wt and a bottom wall Wb as a sixth wall. The back wall Wr, the left side wall Ws1, and the right side wall Ws2 extend in the vertical direction (Z-axis direction) and have a flat wall surface Sa without unevenness.

A front cover Cf as a cover member is disposed from the upper half Wft of the front wall Wf to the front half Wtf of the top wall Wt so as to be openable and closable in the direction of the arrow in FIG. An operator can access the apparatus main body Bd and attach/remove the image forming unit 20 to/from the apparatus main body Bd. To this end, a handle portion pn1 for the operator to grip is formed at a predetermined location on the housing Hz of the image forming unit 20, in the present embodiment, on the top panel pt.

An operation panel 45 is disposed at a portion of the top wall Wt adjacent to the front wall Wf and the right side wall Ws2. The operation panel 45 includes a display section 46 consisting of an LED screen or the like for displaying the status of the printer 10, and an operation section 47 consisting of switches, keys, etc. through which an operator inputs instructions to the printer 10. Further, a stacker sk1 as a first medium stacking section is formed from the center part of the top wall Wt to the back wall Wr, and a sheet of paper as a medium on which an image is formed is placed in the housing Cs facing the stacker sk1. A discharge port h1 for discharging P is formed.

A paper cassette 11 as a medium storage section is disposed at the lower part of the apparatus main body Bd, and sheets P are stacked and stored in a stacker sk2 as a second medium storage section of the paper cassette 11. A paper feeding device e1 is disposed adjacent to the front end of the paper cassette 11, and the paper feeding device e1 is rotatably disposed and serves as a feeding member that feeds out the paper P from the paper cassette 11 as it rotates. a pickup roller 12, a feed roller 13 that sends the paper P fed out in the direction of the arrow by the pickup roller 12 to a paper conveyance path Rt1 as a medium conveyance path; A retard roller 14 is provided as a separating member for separating the sheets one by one.

In the paper transport path Rt1, a pair of transport rollers m1 as a first transport member is located downstream of the paper feeder e1, and a pair of registration rollers m2 as a second transport member is located downstream of the pair of transport rollers m1. , a write sensor s1 as a first medium detection section is disposed downstream of the pair of registration rollers m2. The paper P fed by the paper feeder e1 is transported by a pair of transport rollers m1, the skew is corrected by a pair of registration rollers m2, and the presence or absence of the paper P is detected by a writing sensor s1. Sent to Q1.

The image forming section Q1 includes the image forming unit 20 which is removably disposed with respect to the apparatus main body Bd, an LED head Hd as an exposure device, a transfer roller 21 as a transfer device and a transfer member, etc. Be prepared.

The image forming unit 20 includes a main body 22 and a toner cartridge Ct as a developer storage unit that is integrally or removably disposed with respect to the main body 22. A photoconductor drum 23 as an image carrier freely disposed, a charging roller 24 as a charging device rotatably disposed in contact with the photoconductor drum 23, and a charging roller 24 as a charging device in contact with the photoconductor drum 23. A developing roller 25 as a developer carrying member rotatably disposed in contact with the developing roller 25, a supply roller (not shown) as a developer supplying member rotatably disposed in contact with the developing roller 25, and a photoreceptor drum after transfer. A cleaning device (not shown) for removing toner as a developer remaining on the surface of the developer 23 is provided.

When the surface of the photoreceptor drum 23 is uniformly charged by the charging roller 24 and then exposed to light based on the image data by the LED head Hd, an electrostatic latent image is formed on the surface of the photoreceptor drum 23. An image is formed. Subsequently, toner is applied to the electrostatic latent image by the developing roller 25 to develop the electrostatic latent image, and a toner image as a developer image is formed on the surface of the photoreceptor drum 23. Further, the supply roller is rotated in the same direction as the developing roller 25, supplies the toner supplied into the main body 22 from the toner cartridge Ct to the developing roller 25, and frictionally charges the toner.

The paper P conveyed from the paper cassette 11 through the paper conveyance path Rt1 and supplied to the image forming section Q1 passes through the transfer nip between the photoreceptor drum 23 and the transfer roller 21. As a result, the toner image formed on the photoreceptor drum 23 is transferred.

A fixing device 31 serving as a fixing device is disposed on the downstream side of the image forming section Q1 in the paper transport path Rt1 so as to be detachable from the apparatus main body Bd. The paper P that has passed through the transfer nip is conveyed in the direction of the arrow and sent to the fixing device 31 .

The fixing device 31 includes a heat roller (heating roller) 32 as a first fixing member, and a backup roller (pressure roller) 33 as a second fixing member. A lamp Ht is provided.

A fixing nip is formed between the heat roller 32 and the backup roller 33, and when the paper P supplied to the fixing device 31 passes through the fixing nip, the toner image on the paper P is heated by the heat roller 32. The toner is melted and fixed to the paper P by applying pressure by the backup roller 33. As a result, an image is formed on the paper P.

On the downstream side of the fixing device 31 in the paper transport path Rt1, there is an exit sensor s2 as a second medium detection unit adjacent to the exit of the fixing device 31, and an exit sensor s2 as a third transport member is located downstream of the exit sensor s2. A pair of conveying rollers m3 is disposed downstream of the pair of conveying rollers m3, and a pair of discharge rollers m4 as a fourth conveying member is disposed.

After the presence or absence of the paper P on which the image has been formed in the fixing device 31 is detected by the exit sensor s2, the paper P is transported by a pair of transport rollers m3, and is transported by a pair of ejection rollers m4 from the ejection port h1 to the outside of the main body Bd of the apparatus. direction, and is loaded on the stacker sk1.

By the way, in the printer 10, as described above, the image forming unit 20 is removably disposed in the apparatus main body Bd, and the operator can perform maintenance on the printer 10 and operate the paper conveyance path. The image forming unit 20 can be removed when removing the paper P that caused a media jam, that is, a paper jam while being conveyed through Rt1.

However, when performing maintenance on the printer 10 or removing paper P that has caused a paper jam, the image forming unit 20 removed from the main body Bd is temporarily placed around the printer 10. If there is no place to do so, the operator must place the image forming unit 20 at a location away from the printer 10, which is a cumbersome task. Further, if the place where the image forming unit 20 is placed is not flat, the image forming unit 20 cannot be placed stably, and the photoreceptor drum 23 may be damaged by being hit by foreign objects.

Therefore, in this embodiment, the image forming unit 20 removed from the apparatus main body Bd can be held by the casing Cs of the printer 10.

FIG. 4 is a perspective view of the printer showing the image forming unit according to the embodiment of the present invention removed from the apparatus main body, and FIG. 5 shows the image forming unit according to the embodiment of the present invention removed from the apparatus main body. FIG. 2 is an enlarged view of main parts of the printer shown in FIG. In the figure, the positive direction of the X-axis is the rear direction of the printer 10, the negative direction of the X-axis is the front direction of the printer 10, the positive direction of the Y-axis is the left direction of the printer 10, and the negative direction of the Y-axis is the direction of the printer 10. 10, the Z-axis positive direction is the upward direction in the printer 10, and the Z-axis negative direction is the downward direction in the printer 10.

In the figure, 10 is the printer, Cs is the housing, Wf is the front wall, Wr is the back wall, Ws1 is the left side wall, Ws2 is the right side wall, Wt is the top wall, Bd is the device body, Cf is the front cover, and Rt1 is paper. It is a conveyance path.

As shown in the figure, when the front cover Cf is opened and the image forming unit 20 (FIG. 2) is removed from the apparatus main body Bd, the paper transport path Rt1 is exposed, so that the operator can perform maintenance on the printer 10, It is possible to remove the paper P that caused the paper jam at the lower part of the image forming unit 20.

Further, Ar1 is a transport area for the paper P in the paper transport path Rt1, and in this embodiment, a predetermined location outside the transport area Ar1, that is, between the transport area Ar1 and the left side wall Ws1 and the right side wall Ws2. , an engagement hole 62 serving as an engaged portion within the device main body Bd is formed in the frame portion St1. The engagement hole 62 has a pair of hook-shaped legs 63 (FIG. 1 ).

Then, a pair of engaged parts as engaged parts outside the device main body Bd are placed at a predetermined location of the casing Cs, in this embodiment, at a location adjacent to the right side wall Ws2, which is a predetermined wall of the top wall Wt. A recess 65 is formed. The engagement recess 65 is engaged with the hook-shaped leg 63 when the image forming unit 20 is removed from the apparatus main body Bd.

In this embodiment, as shown in FIG. 4, the engagement recesses 65 are located at the corners of the top wall Wt adjacent to the back wall Wr and the right side wall Ws2, and at the front wall Wf and the right side wall of the top wall Wt. It is formed at the corner adjacent to Ws2, but depending on the width dimension of the image forming unit 20, it may be formed at any two locations on the edge of the right side wall Ws2 of the top wall Wt, or at a predetermined location on the top wall Wt. It can also be formed at a location adjacent to the left side wall Ws1 or the back wall Wr.

Next, the housing Hz of the image forming unit 20 will be explained.

FIG. 6 is a perspective view of an image forming unit in an embodiment of the present invention, FIG. 7 is a sectional view of an image forming unit in an embodiment of the present invention, and FIG. 8 is a plan view of an image forming unit in an embodiment of the present invention. , FIG. 9 is a bottom view of the image forming unit in the embodiment of the present invention. 8 and 9, the X-axis positive direction is the rear direction of the printer 10, the X-axis negative direction is the front direction of the printer 10, the Y-axis positive direction is the left direction of the printer 10, and the Y-axis negative direction is the front direction of the printer 10. The direction is the right direction in the printer 10, the Z-axis positive direction is the upward direction in the printer 10, and the Z-axis negative direction is the downward direction in the printer 10.

In the figure, 20 is an image forming unit, Hz is a housing, 22 is a main body, 23 is a photosensitive drum, Ct is a toner cartridge, and Rm is formed inside the toner cartridge Ct and collects waste toner as waste developer. A waste toner collection chamber 68 serving as a waste developer collection chamber serves as a waste toner transport path that transports the waste toner removed from the photosensitive drum 23 by the cleaning device to the waste toner collection chamber Rm. A line 69 is a film that is disposed at a location facing the LED head Hd in the main body 22 and protects the photosensitive drum 23.

The housing Hz is disposed so as to extend in the top panel pt, the paper P conveyance direction, and has a first side formed on the left side when the image forming unit 20 is viewed from the upstream side in the paper P conveyance direction. It has a left side panel ps1 as a panel, and a right side panel ps2 as a second side panel formed on the right side when image forming unit 20 is viewed from the upstream side in the conveyance direction of paper P.

The handle portion pn1 is formed on the top panel pt, the main body portion 22 and the toner cartridge Ct are disposed between the left side panel ps1 and the right side panel ps2, and the left side panel ps1 and the right side panel ps2. Both ends of the photoreceptor drum 23 are supported by.

Since the lower end of the housing Hz (the end in the Z-axis positive direction when the image forming unit 20 is attached to the apparatus main body Bd) is open, the photosensitive drum 23 can be attached to the apparatus main body Bd when the image forming unit 20 is attached to the apparatus main body Bd. The housing Hz is exposed so as to face the lower end of the housing Hz so that a transfer nip can be formed between the housing Hz and the transfer roller 21 (FIG. 2) when the housing Hz is moved.

At the lower edges of the left side panel ps1 and the right side panel ps2, an "L" shape is formed at one end in the transport direction of the paper P, in this embodiment, at the upstream end. Hook-shaped legs 63 having hook-shaped legs 63 are located near the photoreceptor drum 23 at the lower edges of the left side panel ps1 and right side panel ps2, and drum portion protrusions 71 as protrusions are provided below the left side panel ps1 and right side panel ps2. At the edge, at the other end in the transport direction of the paper P (in this embodiment, at the downstream end), a front support leg 72 as a support section is provided below (the image forming unit 20 is connected to the apparatus main body Bd). It is formed so as to protrude toward the Z-axis (positive direction) when attached to.

The drum portion protrusion 71 prevents the photoreceptor drum 23 from being damaged by hitting a foreign object when the image forming unit 20 is locked to the housing Cs. Further, the front support leg 72 is brought into contact with the wall surface Sa of the right side wall Ws2 (FIG. 3) and supports the image forming unit 20 when the image forming unit 20 is locked in the housing.

In FIG. 9, Ar2 is a region between both ends of the photoreceptor drum 23, that is, a drum region, and the hook-shaped leg 63, drum protrusion 71, and front support leg 72 are formed outside the drum region Ar2. Ru.

Next, a method for locking the image forming unit 20 removed from the apparatus main body Bd to the housing Cs will be described.

FIG. 1 is an enlarged view of main parts of a printer showing a state in which an image forming unit according to an embodiment of the present invention is locked to a housing, and FIG. FIG. 11 is a perspective view of the printer showing a state in which the image forming unit according to the embodiment of the present invention is locked to the housing, and FIG. 12 is a diagram for explaining the procedure for locking the image forming unit according to the embodiment of the present invention. FIG. 6 is a conceptual diagram for explaining a method of setting the length of the front support leg of the forming unit. 1, 10 and 11, the positive direction of the X-axis is the rear direction of the printer 10, the negative direction of the X-axis is the front direction of the printer 10, the positive direction of the Y-axis is the left direction of the printer 10, and the positive direction of the Y-axis is the left direction of the printer 10. The negative axis direction is the right direction in the printer 10, the positive Z axis direction is the upward direction in the printer 10, and the negative Z axis direction is the downward direction in the printer 10.

In the figure, 10 is a printer, Cs is a housing, Bd is a main body of the apparatus, Cf is a front cover, Ws1 is a left side wall, and Ws2 is a right side wall.

Further, 20 is an image forming unit, 22 is a main body, Ct is a toner cartridge, Hz is a housing, pn1 is a handle, 23 is a photosensitive drum, ps1 is a left side panel, ps2 is a right side panel, and 63 is a hook shape. The legs include an engaging recess 65, a drum protrusion 71, and a front support leg 72.

The operator first opens the front cover Cf and removes the image forming unit 20 from the apparatus main body Bd by holding the handle pn1. Next, as shown in FIG. 10, the operator holds the image forming unit 20 with the toner cartridge Ct side up and the main body 22 side down, and moves along the right side wall Ws2 toward the drum part protrusion 71 and the front side. The support leg 72 is slid to engage the hook-shaped leg 63 and the engagement recess 65. Thereby, as shown in FIG. 11, the image forming unit 20 is locked to the housing Cs.

At this time, the height HL of the front support leg 72 is set so that the photoreceptor drum 23 does not come into contact with the wall surface Sa of the right side wall Ws2.

That is, in FIG. 1, the point where the inner tip of the hook-shaped leg 63 is located when the image forming unit 20 is locked in the housing Cs, that is, the hook-shaped leg 63 and the engagement recess 65 engage with each other. The point is defined as the engagement point q1, and the point where the inner root portion of the hook-shaped leg 63 is located when the image forming unit 20 is locked to the housing Cs, that is, the point where the top wall Wt and the right side wall Ws2 intersect is defined as the engagement point q1. A wall intersection q2 is defined as a virtual contact point q3, a point on the wall surface Sa when the photoreceptor drum 23 is brought into virtual contact with the wall surface Sa of the right side wall Ws2 is defined as a virtual contact point q3, and the image forming unit 20 is locked to the housing Cs. The point on the wall surface Sa that the front support leg 72 is brought into contact with is defined as the support contact point q4, which is formed by the root of the front support leg 72 when the image forming unit 20 is locked to the housing Cs. When the point is unit support point q5, the height HL of the front support leg 72 is the distance L1 between the engagement point q1 and the wall intersection q2, the distance L2 between the engagement point q1 and the virtual contact point q3, and It is set based on the distance L3 between the virtual contact point q3 and the unit support point q5.

That is, since the height HL of the front support leg 72 is the distance between the support part contact point q4 and the unit support point q5, each of the distances L1 to L3 and the height HL are as follows.
L2:L3=L1:HL
There is a relationship, and the height HL is
HL=L1・L3/L2
become.

In this case, since the distance LX between the virtual contact point q3 and the photoreceptor drum 23 when the photoreceptor drum 23 is brought into virtual contact with the wall surface Sa is 0, the wall surface Sa and the photoreceptor drum 23 are in contact with each other. In order to avoid this, the height HL is
HL>L1・L3/L2
be made into

In addition, when the height of the drum part protrusion 71 is HM, the relationship between the height HL of the front support leg 72 and the height HM of the drum part protrusion 71 is as follows.
0<HM<HL
be made into

Next, a state in which the image forming unit 20 is attached to the apparatus main body Bd will be described.

FIG. 13 is a diagram showing a state in which the hook-shaped leg and the engagement hole are engaged in the embodiment of the present invention, and FIG. 14 is a diagram showing the state in which the image forming unit in the embodiment of the present invention is attached to the main body of the apparatus. FIG. 15 is a diagram showing a second example in which the image forming unit according to the embodiment of the present invention is attached to the apparatus main body. In the figure, the positive direction of the X-axis is the rear direction of the printer 10, the negative direction of the X-axis is the front direction of the printer 10, the positive direction of the Y-axis is the left direction of the printer 10, and the negative direction of the Y-axis is the direction of the printer 10. 10, the Z-axis positive direction is the upward direction in the printer 10, and the Z-axis negative direction is the downward direction in the printer 10.

In the figure, Ws1 is a left side wall, Rt1 is a paper conveyance path, Ar1 is a conveyance area, St1 is a frame portion, 62 is an engagement hole, 20 is an image forming unit, ps1 is a left side panel, and 63 is a hook-shaped leg.

When the image forming unit 20 is attached to the apparatus main body Bd, the hook-shaped legs 63 formed on the left side panel ps1 and the right side panel ps2 of the image forming unit 20 are connected to the engagement holes 62 formed outside the conveyance area Ar1 for the paper P. need to be engaged.

In this case, as shown in FIGS. 14 and 15, the above-mentioned Since the position of the matching hole 62 is set, it is possible to prevent the photosensitive drum 23 from being damaged by erroneously attaching the image forming unit 20 to the device main body Bd of the printer 10 that is not compatible.

As described above, in the present embodiment, the hook-shaped legs 63 are formed at predetermined locations on the image forming unit 20, the engagement recesses 65 are formed at predetermined locations on the top wall Wt of the casing Cs, and the above-mentioned By engaging the hook-shaped legs 63 and the engagement recesses 65, the image forming unit 20 is locked to the housing Cs, so that the operator can perform maintenance on the printer 10 or prevent paper jams from occurring. There is no need to secure a place to place the image forming unit 20 removed from the apparatus main body Bd when performing work such as removing the paper P that has been removed.

Furthermore, since the image forming unit 20 can be stabilized and locked to the housing Cs, it is possible to prevent the photosensitive drum 23 from being damaged by being hit by foreign objects.

Moreover, since the photosensitive drum 23 is surrounded by the housing Hz of the image forming unit 20 while the image forming unit 20 is locked in the housing Cs, the photosensitive drum 23 is prevented from receiving light. I can do it. Therefore, deterioration of the photoreceptor drum 23 can be suppressed.

In this embodiment, the engagement recess 65 is formed at a location adjacent to the right side wall Ws2 on the top wall Wt, but the engagement recess 65 is formed at a location adjacent to the back wall Wr on the top wall Wt. It can also be formed at a location adjacent to the left side wall Ws1.

In this embodiment, the printer 10 has been described, but the present invention can be applied to image forming apparatuses such as copying machines, facsimile machines, and multifunction devices.

Note that the present invention is not limited to the embodiments described above, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

10 Printer 20 Image forming unit 63 Hook-shaped leg 65 Engagement recess Bd Apparatus main body Cs Housing Sa Wall surface Wr Back wall Ws1 Left side wall Ws2 Right side wall Wt Top wall

Claims (7)

(a) a housing comprising a top wall and a wall extending vertically and having a flat wall surface;
(b) a device main body formed within the housing;
(c) an image forming unit that is removably disposed on the apparatus main body, and
(d) an engaging portion is formed at a predetermined location of the image forming unit;
(e) an engaged portion is formed at a predetermined location on the top wall;
(f) The image forming apparatus is characterized in that the image forming unit is locked to a housing by engaging the engaging portion and the engaged portion. (a) The image forming unit includes a side panel that supports both ends of the image carrier and is disposed to extend in the conveyance direction of the medium;
(b) The image forming apparatus according to claim 1, wherein the engaging portion is formed to protrude downward at one end of the lower edge of the side panel in the medium conveyance direction. (a) a support portion is formed to protrude downward at the other end of the lower edge of the side panel in the medium conveyance direction;
(b) The image forming apparatus according to claim 2, wherein the support portion is brought into contact with the wall surface of the wall to support the image forming unit when the image forming unit is locked to the housing. The height of the support part is HL, and the distance between the engagement point where the engaging part and the engaged part engage and the wall intersection where the top wall and the wall having the wall surface intersect is L1. , a distance between the engagement point and a virtual contact point on the wall surface when the image carrier is brought into virtual contact with the wall surface is L2, and the virtual contact point and the image forming unit are locked to the casing. When the distance between the unit support point formed by the root of the support part is L3, the height HL of the support part is:
HL>L1・L3/L2
The image forming apparatus according to claim 3. (a) The image forming unit includes a side panel that supports both ends of the image carrier and is disposed to extend in the conveyance direction of the medium;
(b) a support portion is formed to protrude downward at the other end of the lower edge of the side panel in the medium conveyance direction;
(c) The height of the support part is HL, and the distance between the engagement point where the engaging part and the engaged part engage and the wall intersection where the top wall and the wall having the wall surface intersect. is L1, the distance between the engagement point and a virtual contact point on the wall surface when the image carrier is brought into virtual contact with the wall surface is L2, and the virtual contact point and the image forming unit are placed in a housing. When the distance from the unit support point formed by the root portion of the support portion when locked is L3, the height HL of the support portion is:
HL>L1・L3/L2
The image forming apparatus according to claim 1. (a) a protrusion is formed near the image carrier at the lower edge of the side panel to protrude downward;
4. The image forming apparatus according to claim 3, wherein (b) the protrusion prevents the image carrier from being damaged due to contact with foreign matter. The image forming apparatus according to claim 1, wherein the engaging portion is engaged with an engagement hole formed in the apparatus main body when the image forming unit is attached to the apparatus main body.

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