JP2010002590A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a photoreceptor drum supported by an image forming unit from being damaged upon pulling out the image forming unit outside an image forming apparatus, where the image forming unit and a belt unit are removably arranged. <P>SOLUTION: In a state where the image forming unit and the belt unit are loaded into the apparatus, leg parts 31b disposed at the lower end of the image forming unit 30 restrain the turning of levers 63 and 64 that restrain the displacement of the belt unit 50, accordingly, it is impossible to pull out the belt unit 50. When the image forming unit 30 starts to be pulled out outside the apparatus, the leg parts 31b separate from the levers 63 and 64, and a protrusion part 31c disposed at the bottom of the image forming unit 30 rotates an auxiliary lever 65 in a direction to restrain the turning of the third lever 63. Accordingly, the displacement of the belt unit 30 is continuously restrained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

In the present invention, an image forming unit that forms an image with a toner image and a belt unit that stretches a belt to which a toner image is transferred or a recording medium to which a toner image is transferred are attached to and detached from the apparatus main body. The present invention relates to an image forming apparatus that is accommodated.

  2. Description of the Related Art Image forming apparatuses in which a toner image formed by attaching toner to a latent image due to a difference in electrostatic potential is transferred onto a recording sheet and is fixed by heating are widely used. In such an image forming apparatus, an image forming body such as an image holding body on which an electrostatic latent image is formed, a charging device for charging the image holding body, and a developing device for visualizing the electrostatic latent image by adhesion of toner is formed. Some units are supported as a unit. In addition, a belt unit that conveys a recording sheet or an intermediate transfer belt to which a toner image is temporarily transferred and a drive unit of the belt are integrally supported. The belt unit and the image forming unit are connected to the main body of the apparatus. Some have been proposed to be removable. By unitizing in this way and making it detachable from the apparatus main body, maintenance and paper clogging are easily performed, and operability can be improved.

Examples of such an image forming apparatus include those described in Patent Document 1 and Patent Document 2.
In the image forming apparatus described in Patent Document 1, a front cover that can be opened and closed is provided on the apparatus main body casing, and the front cover is opened so that the image forming unit and the belt unit can be attached to and detached from the apparatus main body. . The image forming unit is disposed above the belt unit, and the image forming unit is pulled out of the apparatus to perform process cartridge replacement and paper clogging. When maintenance or replacement of the belt unit is necessary, the image forming unit is first pulled out of the apparatus, and the belt unit is lifted out using the space inside the apparatus after the image forming unit is pulled out. It is something to pull out.

In addition, the image forming apparatus described in Patent Document 2 includes an image forming unit that can be attached to and detached from the apparatus main body and a belt unit, similar to the image forming apparatus described in Patent Document 1, and includes a lever and a release lever. By this operation, it is possible to collectively execute the tension application of the conveying belt provided in the belt unit and the positioning of the belt unit, or to release them.
JP 2007-55774 A JP 2007-57953 A

  According to the present invention, in an image forming apparatus in which an image forming unit and a belt unit are detachably arranged, the image forming unit and the belt unit come into contact with each other to damage the image carrier when the image forming unit is pulled out of the apparatus. The purpose is to prevent this.

  In order to solve the above problems, the invention described in claim 1 is directed to an image carrier in which a latent image is formed on an endless peripheral surface, and a toner image is formed by attaching toner to the image carrier. An image forming unit including a plurality of developing devices, and an endless belt that contacts the image holding member and adheres and conveys an endless belt to which the toner image is temporarily transferred or a recording sheet to which the toner image is transferred. A belt unit including a belt and a plurality of roll members that stretch the belt, a transfer device that transfers the toner image to the endless belt or a recording sheet, and heating the toner image to A fixing device that fixes the image on the recording sheet, and the image forming unit and the belt unit can be removed by pulling them out of the housing housing them in the moving direction of the belt unit. The image forming unit restrains the movement of the belt unit when the image forming unit and the belt unit are accommodated in a predetermined position in the housing. When removing the image forming unit, there is provided an image forming apparatus for restraining the movement of the belt unit until the image holding member is pulled out to a predetermined position after being separated from the belt.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, a fixed guide fixed in the housing, a lever supported rotatably around a support shaft provided in the housing, The position of the belt unit is constrained by pressing a member provided on the belt unit against the fixed guide, and the position of the lever unit is constrained in a state where the position of the belt unit is constrained. Rotation is constrained by the image forming unit.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the rotation is provided at a predetermined position in the housing so that the rotation of the lever is restricted and the rotation of the lever is restricted. An auxiliary lever that is movable between an allowable position and a rotation of the lever by contacting the lever when the image forming unit is accommodated in a predetermined position in the housing; When the image forming unit moves in the direction separating the image carrier from the belt and further moves in the direction in which the image forming unit is pulled out from the housing, the image forming unit rotates in contact with the auxiliary lever. And pressed against the lever so as to restrain the rotation of the lever.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second aspect, when the image forming unit is accommodated at a predetermined position in the housing, the lever contacts the lever and rotates the lever. Until the image forming unit moves in a direction to separate the image carrier from the belt, and further moves a predetermined distance in a direction in which the image forming unit is pulled out from the housing. It is assumed that the portion of the unit that faces the lever contacts the lever and restrains the rotation of the lever.

  In the image forming apparatus according to the first aspect, the movement of the belt unit is restricted until the image forming unit is pulled out to a predetermined position. Accordingly, it is possible to prevent damage to the image carrier due to contact between the image carrier and the belt unit, which may occur when both the image forming unit and the belt unit move in the pulling direction.

  In the image forming apparatus according to the second aspect, even in the process of pulling out the image forming unit, the rotation of the lever that restricts the position of the belt unit is restrained by the image forming unit, and the belt unit is positioned and determined in advance. It is constrained not to move at the position.

  In the image forming apparatus according to the third aspect, the position of the belt unit is restrained via the auxiliary lever and the lever while the image forming unit is moved in the direction in which the image forming unit is pulled out from the housing, and the image forming unit is pulled out from the housing. The movement of the belt unit can be constrained while moving in the direction.

  In the image forming apparatus according to the fourth aspect, the rotation of the lever can be restrained in a state where the image forming unit is moved in the direction of being pulled out from the housing, and the image forming unit is moving. Even in this state, the position of the belt unit is constrained. As a result, it is possible to prevent a situation in which both the image forming unit and the belt unit move in the direction in which they are pulled out and come into contact with each other and damage the image carrier.

Hereinafter, embodiments of the invention according to the present application will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus 1 includes four process cartridges 10a, 10b, 10c, and 10d that form yellow, magenta, cyan, and black toner images. The sheet conveying belt faces all of the process cartridges 10. 11 is supported. The sheet transport belt 11 is a belt that moves around with the recording sheet attached on the peripheral surface, and a transfer roll 12 is disposed at a position facing each process cartridge 10 via the sheet transport belt 11. . The recording sheet is fed out from the sheet tray 13 and supplied onto the sheet conveying belt 11 through the conveying path 14. The sheet conveying belt 11 transfers the recording sheet attached by the circular drive to the process cartridge 10 and the transfer roll 12. Are fed to the opposite transfer section. Then, each color toner image is sequentially transferred from each process cartridge onto the recording sheet, and a plurality of color toner images are superimposed on the recording sheet to form a full color toner image. Reference numeral 15 denotes a manual feed path.

A fixing device 20 is disposed on the downstream side in the circumferential movement direction of the sheet conveying belt 11, and the recording sheet to which the toner image has been transferred and peeled off from the sheet conveying belt 11 is heated and pressurized to form toner on the recording sheet. The image is fixed. A sheet discharge roll pair 16 and a sheet discharge tray 17 are provided on the downstream side of the fixing device 20, and a recording sheet on which the toner image is fixed is accommodated in the sheet discharge tray.
In addition, an opening / closing part 2 is provided on one side of the housing of the image forming apparatus, and it can rotate around a support shaft 1b provided at the lower part of the housing to cope with maintenance and management of the apparatus. It has become.

As shown in FIG. 2, the four process cartridges 10a, 10b, 10c, and 10d are accommodated in a frame 31 that integrally supports them, and can be attached to and detached from the image forming apparatus main body as an image forming unit 30. It has become. The sheet conveying belt 11 is also integrally supported by the belt frame 51 together with a plurality of rolls for stretching the belt, and can be attached to and detached from the image forming apparatus main body as a belt unit 50. The belt unit 50 is disposed below the image forming unit 30 so as to face the photosensitive drum 3 of the image forming unit 30, and the image forming unit 30, the belt unit are opened in a state where the opening / closing portion 2 is opened. In order of 50, it can be removed from the image forming apparatus main body toward the upstream side in the recording sheet conveyance direction.
Note that handles 31 a and 51 a are formed in portions corresponding to the opening and closing portions of the image forming unit 30 and the belt unit 50, respectively, and the operator holds the handles 31 a and 51 a to hold the image forming unit 30. Alternatively, the belt unit 50 is attached and detached.

  Each of the process cartridges 10 is capable of forming any one of yellow, magenta, cyan, and black toner images, and is arranged in the frame 31 of the image forming unit 30 at intervals in the horizontal direction. Each is supported so as to be detachable from the frame 31.

  The process cartridge 10 includes a photosensitive drum 3 having a photosensitive layer on an endless peripheral surface, and a charging device that uniformly charges the peripheral surface of the photosensitive drum opposite to the photosensitive drum 3. 4, a developing device 5 that transfers toner onto the photosensitive drum 3, and a cleaning device 6 that removes residual toner on the photosensitive drum 3 are provided. An exposure device 7 for irradiating image light onto the photosensitive drum is provided above the process cartridge 10.

The photosensitive drum 3 is formed by forming an organic photosensitive layer on the peripheral surface of a cylindrical member made of metal, and the metal portion is electrically grounded. After the peripheral surface of the photosensitive drum 3 is charged almost uniformly by the charging device 4, an image light is irradiated from the exposure device 7 to form a latent image on the peripheral surface due to a difference in charging potential. It is what is done.
The charging device 4 includes a roll-shaped member in which a stainless steel cylindrical core metal is covered with a medium-resistance rubber, and the surface of the photosensitive drum 3 is applied by applying a voltage in which an AC component is superimposed on a DC component. It is charged to a desired voltage.

  The developing device 5 uses a two-component developer containing toner and a magnetic carrier. A developing roll 5a is provided at a position close to the photosensitive drum 3, and a thin layer of a two-component developer is formed on the peripheral surface of the developing roll 5a to rotate. As a result, the toner is transferred to the electrostatic latent image on the photosensitive drum 3 at a position facing the photosensitive drum 3 to form a toner image. The toner consumed as a result of image formation is replenished according to the amount consumed.

  The belt unit 50 supports a driving roll 52 and a plurality of stretching rolls 53a, 53b, 53c arranged in parallel by a belt frame 51 so as to be rotatable around an axis, and the sheet conveying belt 11 is supported on these rolls. It is a stretched one. The four transfer rolls 12 are supported so as to be able to rotate around the axis so as to come into contact with the inner peripheral surface of the stretched sheet conveying belt 11.

The sheet conveying belt 11 is made of, for example, a synthetic resin such as flexible PET or polyimide film.
A driving force is transmitted to the driving roll 52 from a driving motor (not shown) supported by the image forming apparatus main body. As a result, the sheet conveying belt 11 is driven to rotate in the direction of arrow A shown in FIG. 1 while being stretched between the drive roll 52 and the plurality of stretch rolls 53a, 53c, 53c.

  The transfer roll 12 is disposed at a position facing the photosensitive drum 3 provided in each process cartridge 10, and a transfer bias voltage is applied between the transfer roll 12 and the photosensitive drum 3. As a result, the toner image on the photosensitive drum 3 is electrostatically transferred to a recording sheet passing through a position where the transfer roll 12 and the photosensitive drum 3 face each other.

  The fixing device 20 includes a heating roll 20a having a built-in heating source and a pressure roll 20b pressed against the heating roll 20a, and these are arranged in parallel to form a nip portion that is pressed against each other. ing. The recording sheet to which the toner image has been transferred is fed into the nip portion, heated and heated between the heated roll 20a and the pressure roll 20b that are rotationally driven, and the softened toner is pressed onto the recording sheet. It is supposed to be.

Next, a configuration in which the image forming unit 30 and the belt unit 50 are detachably accommodated in the image forming apparatus main body will be described.
FIG. 3 is a schematic cross-sectional view showing a state in which the image forming unit 30 and the belt unit 50 are accommodated in the housing of the image forming apparatus main body, and FIG. 4 shows that the image forming unit 30 is opened from the opening / closing part 2 provided in the housing. It is a schematic sectional drawing which shows the state which is moving to the direction taken out out of an apparatus.
As shown in FIG. 3, the frame 31 that supports the process cartridge 10 is provided with two projections 32 and 33 for supporting and positioning the image forming unit 30. The protrusions 32 and 33 are members having a circular cross section provided so as to protrude laterally at the front and rear portions in the drawing direction of the frame 31, respectively. On the other hand, a first guide 41 and a second guide 42 for guiding these protrusions 32 and 33 are provided at positions corresponding to the protrusions 32 and 33 inside the housing of the image forming apparatus main body. However, the frame 31 is accommodated in the operating position in the housing by sliding on these guides 41 and 42.

  The first guide 41 guides the projection 32 on the front side in the direction in which the frame 31 is pulled out, and the second guide 42 guides the projection 33 on the rear side. Each of these guides has horizontal portions 41a and 42a on the front side, and has inclined portions 41b and 42b that descend toward the rear in the vicinity of the rear end. Stoppers 41c and 42c for positioning the protrusions 32 and 33 are provided at the rear end. Therefore, the protrusions 32 and 33 guided by these guides slide on the horizontal portions 41a and 42a and move rearward, then descend along the inclined portions 41b and 42b, and the bottom portions of the inclined portions 41b and 42b. That is, it is positioned and supported at the rear end.

  Further, in the vicinity of the rear ends of the first guide 41 and the second guide 42, resistance is given to the protrusions 32 and 33 that have reached the rear ends of the guides 41 and 42 moving forward. A first lever 43 and a second lever 44 are provided. These levers 43 and 44 are supported by the main body of the image forming apparatus, and are provided to be rotatable around support shafts 43a and 44a parallel to the protruding direction of the protrusions 32 and 33. These levers 43 and 44 are urged around a support shaft by a spring (not shown) to press the protrusions 32 and 33 supported on the rear ends of the guides 41 and 42 against the guides 41 and 42. . Accordingly, when the image forming unit 30 is attached to the image forming apparatus main body, the protrusions 32 and 33 move along the first guide 41 and the second guide 42, respectively, and when the image forming unit 30 reaches the rear end, the first The lever 43 and the second lever 44 are pushed up and fitted into the operating position to be positioned. Further, when the image forming unit 30 is pulled out, the protrusions 32 and 33 are moved from the state where the protrusions 32 and 33 are positioned at the rear end portions of the guides 41 and 42 to move backward obliquely so as to push up the levers 43 and 44. The biased levers 43 and 44 provide resistance to this movement.

  On the other hand, the belt frame 51 of the belt unit 50 is also provided with two protrusions 54 and 55 for supporting and positioning the belt frame 51 as in the image forming unit 30. These protrusions 54 and 55 are provided so as to protrude laterally at the front and rear portions in the pull-out direction of the belt frame 51, respectively, and the third guide 61 and the third guide 61 provided on the image forming apparatus main body. Guided by the fourth guides 62, the belt frame 51 can be mounted at the operating position in the housing.

  The third guide 61 and the fourth guide 62 both have front horizontal portions 61a and 62a, inclined portions 61b and 62b descending rearward in the vicinity of the rear end, and positioning of protrusions at the rear end. And stoppers 61c and 62c. Accordingly, the protrusions 54 and 55 are guided by these guides 61 and 62, and the belt frame 51 slides on the horizontal portions 61a and 62a in the same manner as the frame 31 of the image forming unit 30, and then the inclined portions 61b and 62b. And is supported by being positioned in the rear end portions 61c and 62c.

  Further, in the vicinity of the rear end portions of the third guide 61 and the fourth guide 62, there is resistance to the protrusions 54 and 55 positioned at the rear end portions of the guides 61 and 62 moving forward. A third lever 63 and a fourth lever 64 to be provided are provided in the image forming apparatus main body. These levers 63 and 64 are rotatably provided in the same manner as the levers 43 and 44 for pressing the projections 32 and 33 of the image forming unit 30, and are urged around the support shafts 63a and 64a by a spring to be belt frame 51. The projections 54 and 55 are pressed against the rear ends of the guides 61 and 62. Accordingly, the belt unit 50 is maintained at the operating position of the image forming apparatus main body, and resistance is applied when the belt unit 50 is pulled out.

  When the image forming unit 30 and the belt unit 50 are mounted on the image forming apparatus main body, first, the belt unit 50 is first guided by the third guide 61 and the fourth guide 62 and mounted at the operating position. The image forming unit 30 is attached to the camera. When the image forming unit 30 is mounted, the projections 32 and 33 of the image forming unit 30 are guided along the horizontal portions 41a and 42a of the first guide 41 and the second guide 42, and then along the inclined portions 41b and 42b. As a result, the image forming unit 30 moves downward. As a result, the photosensitive drum 3 exposed downward at the bottom of the image forming unit is brought into contact with the sheet conveying belt 11 of the belt unit 50 already accommodated below, and the photosensitive drum 3 is interposed via the sheet conveying belt 11. It faces the transfer roll 12.

When the image forming unit 30 is lowered onto the belt unit 50 in this way, the leg portions 31b protruding downward from the lower surface before and after the frame 31 of the image forming unit 30 are the third lever 63 and the fourth lever. Abutting or approaching the top of 64, the rotation of the third lever 63 and the fourth lever 64 is restrained. Accordingly, the protrusions 54 and 55 of the belt frame 51 are pressed against the third guide 61 and the fourth guide 62. Therefore, in a state where the image forming unit 30 and the belt unit 50 are mounted, even if the operator tries to grip and pull the handle 51a of the belt unit 50, the belt unit 50 has the third lever 63 and the fourth lever. It is restrained by 64 and it is in the state which cannot be pulled out.
The leg portion 31b provided on the frame 31 of the image forming unit 30 is placed on the photosensitive drum 3 when the image forming unit 30 is taken out from the image forming apparatus main body and temporarily placed on a desk or the like. It also has a function of preventing the photosensitive drum 3 from being damaged due to contact with the surface.

Further, in the image forming apparatus 1, in the process of pulling out the image forming unit 30, that is, in a state where a part of the image forming unit 30 is pulled out from the housing of the image forming apparatus main body, the position of the belt unit 50 is Means are provided for restraining.
This means includes a protruding portion 31c provided so as to protrude downward from the lower portion of the frame 31 of the image forming unit 30, and an auxiliary lever 65 that is rotatably attached to the image forming apparatus main body.

  The auxiliary lever 65 is provided in the vicinity of the third lever 63 and is supported so as to rotate around a support shaft 65 a parallel to the support shaft 63 a of the third lever 63. And it supports by the spring so that it may rest at the initial position in a rotation direction, and rotation to this both from the initial position is possible. As shown in FIG. 3, the initial position is a position where the protruding portion 31 c hits the auxiliary lever 65 when the image forming unit 30 is pulled out from the image forming apparatus main body. Accordingly, when the image forming unit 30 is pulled out from the main body of the image forming apparatus, the protrusion 31c contacts the auxiliary lever 65 and rotates the auxiliary lever 65 in a direction approaching the third lever 63, that is, clockwise in FIG. Is. The tip of the rotated auxiliary lever 65 is brought into contact with the third lever 63 and presses the third lever 63 against the protrusion 54 supported by the third guide. In this state, the auxiliary lever 65 is pressed against the projecting portion 31c provided on the frame 31 of the image forming unit 30, and the rotation is restrained.

With such a configuration, when the image forming unit 30 is pulled out from the main body of the image forming apparatus, the auxiliary lever 65 rotates and is constrained to rotate against the third lever 63, thereby restricting the rotation of the auxiliary lever 65. The rotation of the third lever 63 is restrained. Accordingly, the protrusion 54 on the front side of the belt unit 50 is restrained by the third lever 63 at the rear end portion of the third guide 61, and the belt unit 50 is restrained in a state where it cannot move in the pulling-out direction.
As shown in FIG. 4, the protruding portion 31 c of the frame 31 that restrains the auxiliary lever 65 has a horizontal side at the lower end, and in the process of pulling out the image forming unit 30, the lower side of the protruding portion 31 c. Slides with the auxiliary lever 65 pressed. Therefore, even if the image forming unit 30 moves in the direction in which the image forming unit 30 is pulled out, the state in which the position of the belt unit 50 is constrained in a range where the protruding portion 31c faces the auxiliary lever 65 is maintained.

  When the image forming unit 30 is further pulled out and pulled out from the image forming apparatus main body, the protruding portion 31c is detached from the auxiliary lever 65, and the auxiliary lever 65 returns to the initial position by the action of the spring. Accordingly, the third lever can be rotated, and the belt unit 50 can be lifted obliquely upward and pulled out from the image forming apparatus main body. That is, the position at which the protruding portion 31c is detached from the auxiliary lever 65 is a predetermined position. Here, the shape of the projecting portion 31c may be selected as appropriate, but it is preferably while the image forming unit 30 is being pulled out and the operator can touch the handle 51a of the belt unit 50. If the portion 31c is set so as not to be detached from the auxiliary lever 65, both the image forming unit 30 and the belt unit 50 are not pulled out simultaneously, and contact between the photosensitive drum 3 and the sheet conveying belt 11 is prevented. .

  On the other hand, when the belt unit 50 is mounted on the image forming apparatus main body and then the image forming unit 30 is mounted, the auxiliary lever 65 is stationary at the initial position, and the protruding portion 31 c provided on the lower side of the frame 31 is Contact the auxiliary lever 65. At this time, the auxiliary lever 65 is pushed by the protruding portion 31c that moves backward, and rotates in the direction opposite to that when the image forming unit 30 is pulled out, that is, counterclockwise in FIG. It is not to be.

Next, an image forming apparatus according to another embodiment of the present invention will be described.
FIG. 5 is a schematic configuration diagram illustrating a state in which the image forming unit and the belt unit of the image forming apparatus are positioned and mounted in the apparatus, and FIG. 6 is a state in which the image forming unit is partially extracted. FIG.

  This image forming apparatus includes an image forming unit 30 and a belt unit 50 similar to the image forming apparatus shown in FIG. 3, and these are detachably provided. Further, the projections 32, 33, 54, 55 provided on the image forming unit 30 and the belt unit 50 are guided by guides 41, 42, 61, 62 provided on the main body of the image forming apparatus, and are attached to the operating positions. And the point which can be extracted from this position also has the same structure. The position of the belt unit 50 is constrained so that the belt unit 50 is not moved due to an error or the like until the image forming unit 30 is pulled out and extracted.

  In this image forming apparatus, no auxiliary lever is provided as a means for restraining the belt unit 50, and the third lever 63 is directly restrained by the protruding portion 31 d provided at the lower part of the frame 31 of the image forming unit 30. It has become a thing. That is, the shape of the protruding portion 31d protruding downward corresponds to the movement locus of the image forming unit 30, and when the image forming unit 30 is drawn and moved along the guides 41 and 42, as shown in FIG. The lower side of the projecting portion 31d is maintained in contact with or close to the top of the third lever 63. Accordingly, as shown in FIG. 5, the position of the belt unit 50 is restrained in a state where the image forming unit 30 and the belt unit 50 are attached to the operating position of the image forming apparatus main body, and as shown in FIG. Even in the state where the forming unit 30 is pulled out, the rotation of the third lever 63 is restrained by the projecting portion 31d of the frame 31, and the state where the movement of the belt unit 50 is restrained is maintained.

Although FIG. 7 does not restrict the movement of the belt unit 50, the image formation in which the photosensitive drum 3 and the like are prevented from being damaged by the movement of the belt unit 50 due to an error or the like when the image forming unit 30 is moved. It is a schematic block diagram which shows an apparatus as a reference example.
This image forming apparatus also includes an image forming unit 30 and a belt unit 50 similar to the image forming apparatus shown in FIG. 3 or FIG. 5, and these are detachably mounted by the same mechanism.

The image forming unit 30 and the belt unit 50 are respectively provided with handles 31a and 51a at positions corresponding to the opening / closing portion 2 provided in the housing of the image forming apparatus main body. The image forming unit 30 or the belt unit 50 is pulled out or attached by holding the 51a. The frame 31 of the image forming unit provided in the image forming apparatus has a shape in which a front side 31e in a direction in which the image forming unit is pulled out is extended downward so as to cover the front of the belt unit 50. As a result, when both the image forming unit 30 and the belt unit 50 are attached to the main body of the image forming apparatus and when the image forming unit 30 is partially pulled out, the handle 51a of the belt unit 50 moves forward of the image forming unit 30. It is difficult to be held by the operator.
Accordingly, the operator does not perform an erroneous operation of gripping and moving the handle 51a of the belt unit 50 until the image forming unit 30 is pulled out and removed from the image forming apparatus main body, and the belt is moved during the movement of the image forming unit 30. Damage to the photosensitive drum and the like due to movement of the unit 50 can be prevented.

In the image forming apparatus described above, the belt stretched around the belt unit is a sheet transport belt that adheres and transports a recording sheet. In the present invention, the belt stretched around the belt unit is a toner image. An intermediate transfer belt to which a toner image is directly transferred from an image carrier on which the toner is formed may be used. The intermediate transfer belt superimposes toner images sequentially transferred from the image carrier of the process cartridge on the belt, and then transfers the toner images to a recording sheet.
Further, the process cartridge including the image holding member is not limited to the above-described configuration, and various types generally known in the configuration for forming a toner image can be adopted.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram illustrating an image forming unit and a belt unit of the image forming apparatus illustrated in FIG. 1. FIG. 3 is a schematic configuration diagram illustrating a mechanism that detachably supports an image forming unit and a belt unit of the image forming apparatus illustrated in FIG. 2. FIG. 3 is a schematic configuration diagram showing a mechanism for detachably supporting an image forming unit and a belt unit of the image forming apparatus shown in FIG. 2, and showing a process of pulling out the image forming unit from the image forming apparatus main body. It is a schematic block diagram which shows the mechanism which supports the image forming unit and belt unit of the image forming apparatus which is other embodiment of the invention which concerns on this application so that attachment or detachment is possible. FIG. 6 is a diagram showing a process of pulling out the image forming unit of the image forming apparatus shown in FIG. 5 from the image forming apparatus main body. 1 is a schematic configuration diagram showing an image forming apparatus related to the invention according to the present application as a reference.

Explanation of symbols

1: Image forming device, 2: Opening / closing section, 3: Photoconductor drum, 4: Charging device, 5: Developing device, 6: Cleaning device, 7: Exposure device,
10a, 10b, 10c, 10d: process cartridge, 11: sheet transport belt, 12: transfer roll, 13: sheet tray, 14: transport path, 15: manual transport path, 16: pair of transport rolls, 17: discharge tray, 20: Fixing device,
30: Image forming unit, 31: Frame of image forming unit, 31a: Handle, 31b: Leg part of frame, 31c, 31d: Projecting part of frame, 32, 33: Projection,
41: 1st guide, 42: 2nd guide, 43: 1st lever, 44: 2nd lever,
50: Belt unit 51: Belt frame 51a: Handle 52: Drive roll 53: Stretch roll 54, 55: Projection
61: Third guide 62: Fourth guide 63: Third lever 64: Fourth lever 65: Auxiliary lever

Claims (4)

An image forming unit including a plurality of image carriers each having a latent image formed on an endless peripheral surface, and a plurality of developing devices that form toner images by attaching toner to the image carriers;
An endless belt that contacts the image carrier and temporarily transfers the toner image or an endless belt that adheres and conveys a recording sheet to which the toner image is transferred, and a plurality of rolls that stretch the belt A belt unit comprising a member,
A transfer device for transferring the toner image to the endless belt or to a recording sheet;
A fixing device that heats and fixes the toner image on the recording sheet,
The image forming unit and the belt unit can be pulled out from the housing for accommodating them in the moving direction of the belt unit and removed.
The image forming unit includes:
When the image forming unit and the belt unit are accommodated in a predetermined position in the housing, the movement of the belt unit is restrained.
When removing the image forming unit, the movement of the belt unit is restrained until the image holding member is pulled out to a predetermined position after being separated from the belt. A fixed guide fixed in the housing;
A lever supported to be rotatable around a support shaft provided in the housing,
The position of the belt unit is restricted by pressing a member provided on the belt unit against the fixed guide.
The image forming apparatus according to claim 1, wherein the rotation of the lever is restrained by the image forming unit in a state where the position of the belt unit is restrained. An auxiliary lever that is rotatably provided at a predetermined position in the housing and that is movable between a position that restrains rotation of the lever and a position that allows rotation of the lever;
When the image forming unit is accommodated in a predetermined position in the housing, the image forming unit comes into contact with the lever and restrains rotation of the lever;
When the image forming unit moves the image carrier in a direction away from the belt, and further moves the image forming unit in a direction in which the image forming unit is pulled out from the housing, the image forming unit is rotated in contact with the auxiliary lever. The image forming apparatus according to claim 2, wherein the image forming apparatus is pressed against the lever so as to restrain the rotation of the image forming apparatus. When the image forming unit is accommodated in a predetermined position in the housing, the image forming unit comes into contact with the lever and restrains rotation of the lever;
The lever of the image forming unit until the image forming unit moves in a direction to move the image carrier away from the belt and further moves a predetermined distance in a direction to pull out the image forming unit from the housing. The image forming apparatus according to claim 2, wherein a portion opposed to the lever is in contact with the lever so as to restrain rotation of the lever.

Images