JP6911407B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

In the image forming apparatus, the techniques described in Patent Documents 1 and 2 below are conventionally known with respect to a configuration in which an image holder unit including an image holder and a transfer unit having a transfer member can be attached and detached.

Japanese Patent Application Laid-Open No. 2002-274686 as Patent Document 1 describes a configuration in which the transfer roller (5) is removed after the sheet material guide member (15) is removed from the transport unit (14). In the configuration described in Patent Document 1, the image forming portion is usually configured as a unit so as to be detachable from the front, and the transport unit (14) is transferred by opening the side cover of the double-sided transport portion (13). The roller (5) is attached and detached.

According to Japanese Patent Application Laid-Open No. 2005-242082 as Patent Document 2, when the lower cover (55) on the side surface of the image forming apparatus is opened, the internal electrostatic transfer belt unit (5) becomes removable and the photoconductor (photoreceptor (5)). A configuration is described in which the cartridge (7) having 1) can also be attached and detached.

JP-A-2002-274686 ("0019" to "0023", FIGS. 1 to 5) Japanese Unexamined Patent Publication No. 2005-242082 ("0039" to "0049", FIG. 5)

The present invention is a space in which the image holder unit is attached and detached, and when the user removes the transfer unit through a space extending in a diagonal direction with respect to the first direction connecting the image holder and the transfer member, the user can remove the transfer unit. It is a technical issue to facilitate the attachment / detachment work of the transfer unit as compared with the case where the transfer unit cannot be removed unless the transfer unit is once moved in the first direction.

In order to solve the technical problem, the image forming apparatus of the invention according to claim 1 is used.
An image holder unit that includes an image holder and is detachably supported with respect to the main body of the image forming apparatus.
A transfer unit that is arranged to face the image holder in a transfer region and includes a transfer member that transfers an image of the surface of the image holder to a medium and is detachably supported by the main body of the image forming apparatus.
The main body of the image forming apparatus is composed of a space extending obliquely with respect to a first direction connecting the image holder and the rotation axes of the transfer member when viewed in the rotation axis direction of the transfer member or the image holder. With respect to the passing portion through which the image holder unit is attached and detached,
A transfer unit that moves in only one diagonal direction through the passing portion and is detachably supported with respect to the main body of the image forming apparatus.
A pressing member that is supported by the main body of the image forming apparatus and presses the transfer unit toward the image holder.
A positioning unit that is arranged in the main body of the image forming apparatus, is arranged downstream of the transfer unit mounting direction and downstream of the transfer region with respect to the medium transport direction, and positions the transfer unit.
A regulating unit that is arranged upstream of the transfer unit mounting direction and upstream of the transfer region with respect to the medium transport direction and regulates the movement of the transfer unit in the pressing direction by the pressing member.
A regulated portion that can move between a regulated position that comes into contact with the regulated portion and restricts the movement of the transfer member and a released position that is released from contact with the regulated portion and the regulation is released. With the transfer unit having
Equipped with a,
When the regulated portion moves to the release position, the transfer unit moves by the force of the pressing member toward the image holder and toward the removal side of the passing portion.
And wherein a call.

The invention according to claim 2 is the image forming apparatus according to claim 1.
The regulating unit, which regulates the movement of the transfer unit in the mounting direction to the upstream side and also regulates the movement in the pressing direction.
It is characterized by being equipped with.

The invention according to claim 3 is the image forming apparatus according to claim 1.
The transfer unit, which is rotatably supported in the direction of approaching and separating from the image holder with the positioning portion as the center of rotation.
It is characterized by being equipped with.

The invention according to claim 4 is the image forming apparatus according to claim 1.
The regulated portion, which can be moved from the regulated position to the released position according to the operation of the operator.
It is characterized by being equipped with.

The invention according to claim 5 is the image forming apparatus according to any one of claims 1 to 4.
The image having the restricting portion, which, when the image holder unit is attached to the main body of the image forming apparatus, comes into contact with the regulated portion provided in the transfer unit and restricts the movement of the transfer unit. holder unit,
It is characterized by being equipped with.

The invention according to claim 6 is the image forming apparatus according to any one of claims 1 to 5.
The transfer unit having a guide member for guiding the medium,
It is characterized by being equipped with.

The invention according to claim 7 is the image forming apparatus according to claim 6.
The guide member arranged on the upstream side of the transfer region, wherein the downstream end of the guide member projects toward the image holder side from the tangent line of the transfer member in the transfer region.
It is characterized by being equipped with.

According to the first aspect of the present invention, the transfer unit is attached and detached through a space extending in a diagonal direction with respect to a first direction connecting the image holder and the transfer member. It is possible to facilitate the attachment / detachment work of the transfer unit as compared with the case where the transfer unit cannot be removed unless the user once moves the transfer unit in the first direction when removing the transfer unit.
Further, according to the invention of claim 1 , as compared with the case where the pressing member is not provided, the position can be stably regulated by the regulating portion even if there is rattling, and the position of the transfer member can be stabilized. Can be done.
Further, according to the invention of claim 1, the movement of the transfer unit can be restricted and released by the movement of the regulated portion.
According to the second aspect of the present invention, the regulation unit can regulate the movement in both the mounting direction and the pressing direction.
According to the third aspect of the present invention, the workability of the transfer unit attachment / detachment work can be improved as compared with the case where the transfer unit does not rotate about the positioning portion.

According to the fourth aspect of the present invention, the movement of the transfer unit can be restricted and released by the operation of the operator.
According to the fifth aspect of the present invention, the movement of the transfer unit can be restricted and released in conjunction with the attachment / detachment of the image holder unit.
According to the invention of claim 6 , the guide member can be replaced according to the replacement of the transfer unit.
According to the invention of claim 7 , the occurrence of image defects can be reduced as compared with the case where the downstream end of the guide member does not protrude toward the image holder side from the tangent line.

FIG. 1 is an overall explanatory view of the image forming apparatus of the first embodiment. FIG. 2 is an explanatory diagram of a main part of the image forming portion. FIG. 3 is a view seen from the rear of the transfer unit of the first embodiment. FIG. 4 is an explanatory view of the transfer unit of the first embodiment, FIG. 4A is an explanatory view of a state in which the transfer unit is attached to the main body of the image forming apparatus, and FIG. 4B is a state in which the restriction on the position of the transfer unit is released. It is explanatory drawing. FIG. 5 is an explanatory diagram of the second embodiment and is a diagram corresponding to FIG. 2 of the first embodiment.

Next, an embodiment as a specific example of the embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate the understanding of the following description, in the drawings, the front-back direction is the X-axis direction, the left-right direction is the Y-axis direction, and the up-down direction is the Z-axis direction. The directions indicated by Z and −Z or the indicated sides are defined as front, rear, right, left, upward, downward, or front, rear, right, left, upper, and lower, respectively.
In addition, in the figure, the one with "・" in "○" means the arrow from the back of the paper to the front, and the one with "×" in "○" is the front of the paper. It shall mean an arrow pointing from to the back.
In addition, in the explanation using the following drawings, the illustrations other than the members necessary for the explanation are omitted as appropriate for the sake of easy understanding.

FIG. 1 is an overall explanatory view of the image forming apparatus of the first embodiment.
FIG. 2 is an explanatory diagram of a main part of the image forming portion.
In FIG. 1, the printer U as an example of the image forming apparatus of the first embodiment of the present invention has a printer main body U1 as an example of the image forming apparatus main body. An discharge tray TRh as an example of the discharge unit is formed on the upper surface of the printer main body U1.
The printer U of the first embodiment has a controller C as an example of a control unit. The image processing unit GS, the laser drive circuit DL as an example of the latent image forming circuit, and the power supply circuit E are electrically connected to the controller C. Therefore, the controller C can output a control signal to the image processing unit GS or the like.

Inside the printer U, a photoconductor PR as an example of an image holder is rotatably supported. In FIGS. 1 and 2, around the photoconductor PR, as an example of a charging roll CR as an example of a charging member, a latent image forming device LH, a developing device G, and a transfer member along the rotation direction of the photoconductor PR. The transfer roll Tr and the photoconductor cleaner CL as an example of the cleaning device for the image holder are arranged.
The latent image forming apparatus LH of the first embodiment is an apparatus in which LEDs as an example of latent image writing elements: Light Emitting Diodes are linearly arranged at preset intervals along the left-right direction, so-called LEDs. It is composed of heads.

A toner cartridge TC, which is an example of a container for containing a developer, is detachably supported above the front of the developing apparatus G. The developer from the toner cartridge TC is configured to be replenishable to the developing apparatus G.
In the first embodiment, the photoconductor PR and the developing device G are configured to be integrally detachable from the printer main body U1 as a process unit Ua as an example of the image holder unit. The toner cartridge TC of the first embodiment is configured to be detachable from the process unit Ua. Therefore, it is possible to attach / detach only the toner cartridge TC from the printer main body U1, and it is also possible to attach / detach the toner cartridge TC integrally with the process unit Ua.

In FIG. 1, a paper feed tray TR1 as an example of a medium accommodating portion is arranged below the printer U. The paper feed tray TR1 is configured to be able to be pulled out and inserted forward with respect to the printer main body U1. A pickup roll Rp as an example of the medium take-out member is arranged on the front portion of the paper feed tray TR1.
A paper feed path SH1 as an example of a medium transport path is formed from the pickup roll Rp toward the transfer region Q4 where the photoconductor PR and the transfer roll Tr face each other. A transport roll Ra as an example of a medium transport member is arranged along the paper feed path SH1.

A manual feed tray TR0 is provided at the front of the printer U. The manual feed tray TR0 of the first embodiment can be used by opening the front cover U1a of the printer main body U1. A manual feed path SH0 as an example of a medium transport path extends from the manual feed tray TR0. The manual feed path SH0 joins the paper feed path SH1.
On the upstream side of the transfer region Q4, a register roll Rr as an example of a medium transporting member is arranged.

A fixing device F is arranged on the downstream side of the transfer region Q4. The fixing device F has a pair of fixing rolls Fh and Fp as an example of the fixing member, and the fixing region Q6 is formed by the contact region of the pair of fixing rolls Fh and Fp.
A paper discharge path SH2 as an example of a medium transport path extends from the fixing device F toward the discharge tray TRh. A discharge roll Rh as an example of a discharge member is arranged at the downstream end of the paper discharge path SH2.
Further, an inversion path SH3 as an example of a medium transport path extends from the discharge roll Rh toward the upstream side of the register roll Rr. The medium transport path SH of the first embodiment is configured by the manual feed path SH0, the paper feed path SH1, the paper discharge path SH2, and the reverse path SH3.

(Explanation of image formation operation)
Print information is transmitted to the controller C of the printer U from a host computer or the like as an example of an external information transmission device. When the controller C receives the print information, the image forming operation is started. The controller C outputs the print information to the image processing unit GS. The image processing unit GS converts the print information into image information for forming a latent image and outputs the print information to the laser drive circuit DL as an example of the image writing circuit at a preset time, that is, at a timing. The laser drive circuit DL outputs a drive signal to the latent image forming apparatus LH according to the input image information.

When the image forming operation is started, the photoconductor PR starts rotating.
A charging voltage is applied to the charging roll CR from the power supply circuit E. In the charging region Q1 where the charging roll CR and the photoconductor PR face each other, the charging roll CR charges the surface of the photoconductor PR.
The latent image forming apparatus LH forms an electrostatic latent image according to the image information on the surface of the photoconductor PR in the writing region Q2.

In the developing apparatus G, in the developing region Q3 where the developing roll Ga and the photoconductor PR face each other as an example of the developing agent holder, the electrostatic latent image of the photoconductor PR can be processed by the developing agent held on the developing roll Ga. Develop into a visual image.
The developer is supplied from the toner cartridge TC to the developing device G according to the amount of the developing agent consumed by the developing device G.

The pickup roll Rp sends out the recording sheet S housed in the paper feed tray TR1.
The sent out recording sheet S is sent to the register roll Rr through the paper feed path SH1 on the transport roll Ra. The recording sheet S of the bypass tray TR0 is sent to the register roll Rr through the bypass path SH0. The regiroll Rr conveys the recording sheet S to the transfer region Q4 at the time when the image on the surface of the photoconductor PR reaches the transfer region Q4.
A transfer voltage is applied to the transfer roll Tr from the power supply circuit E. The transfer roll Tr transfers the toner image on the photoconductor PR to the recording sheet S that passes through the transfer region Q4.
The photoconductor cleaner CL removes residual toner on the surface of the photoconductor PR in a cleaning area Q5 as an example of a cleaning area set on the downstream side of the transfer area Q4.

The recording sheet S on which the toner image is transferred in the transfer region Q4 is conveyed to the fixing device F in a state where the toner image is not fixed.
The fixing device F fixes the unfixed toner image of the recording sheet S in the fixing region Q6 which is the contact region of the fixing rolls Fh and Fp.
The recording sheet S on which the toner image is fixed is conveyed through the paper discharge path SH2 to the discharge roll Rh.
When double-sided printing is performed, the discharge roll Rh conveys the recording sheet S toward the reversing path SH3. The recording sheet S conveyed on the reversing path SH3 is sent to the registration roll Rr, and printing on the second side is performed.
The printed recording sheet S is discharged to the discharge tray TRh by the discharge roll Rh.

(Description of process unit and transfer unit)
In FIG. 1, a unit attachment / detachment space 1 extending inward from the front end is formed inside the printer main body U1 of the first embodiment as an example of a passing portion. The unit attachment / detachment space 1 of the first embodiment is composed of a space extending obliquely with respect to the opposite direction (first direction) connecting the rotation center of the photoconductor PR and the rotation center of the transfer roll Tr. The process unit Ua of the first embodiment is configured to be detachable through the unit attachment / detachment space 1 when the front cover U1a is opened.

FIG. 3 is a view seen from the rear of the transfer unit of the first embodiment.
FIG. 4 is an explanatory view of the transfer unit of the first embodiment, FIG. 4A is an explanatory view of a state in which the transfer unit is attached to the main body of the image forming apparatus, and FIG. 4B is a state in which the restriction on the position of the transfer unit is released. It is explanatory drawing.
In FIGS. 3 and 4, a transfer unit support member 6 is arranged at the bottom of the unit attachment / detachment space 1 of the first embodiment. The transfer unit support member 6 is formed in a plate shape extending in an oblique direction in which the unit attachment / detachment space 1 extends. An arc-folded folded-back portion 7 is formed at the inner end of the transfer unit support member 6 as an example of the positioning portion. Further, a bent portion 8 is formed on the front side of the folded portion 7 in accordance with the outer shape of the transfer unit described later.

Openings 9 penetrating the transfer unit support member 6 are formed at both left and right ends between the folded portion 7 and the bent portion 8.
A pressing member 11 is arranged in the opening 9. The pressing member 11 has a pressing head 11a at the upper end as an example of the contact portion, and a spring 11b as an example of the urging member that pushes the pressing head 11a toward the photoconductor PR. The force pressed by the spring 11b is set according to the contact pressure between the transfer roll Tr and the photoconductor PR in the transfer region Q4.

Further, a hook 12 as an example of the regulating portion is supported on the front side of the bent portion 8, that is, on the upstream side of the transfer region Q4. A pair of hooks 12 of the first embodiment are provided at both ends of the transfer unit support member 6 in the left-right direction. The hook 12 has a pillar portion 12a extending upward. A rear protrusion 12b extending rearward is formed on the upper portion of the pillar portion 12a. A step portion 12c is formed between the rear protrusion portion 12b and the upper end of the pillar portion 12a.
A front protrusion 12d extending forward is formed at the upper end of the pillar 12a. A lower protrusion 12e extending downward is formed at the front end of the front protrusion 12d.

In FIGS. 1 to 4, in the printer U of the first embodiment, the transfer roll Tr is detachably supported as a transfer unit Ub with respect to the printer main body U1. In the transfer unit Ub of the first embodiment, in addition to the transfer roll Tr, the paper guide 16 as an example of the guide member arranged on the upstream side of the transfer region Q4 is also integrated with the printer body U1 as the transfer unit Ub. It is configured to be removable.
The paper guide 16 of the first embodiment guides the recording sheet S sent out from the register roll Rr to the transfer region Q4. In addition, in FIGS. 2 and 4, in the paper guide 16 of Example 1, the downstream end 16a protrudes toward the photoconductor PR side from the tangent line L1 of the transfer roll Tr in the transfer region Q4.

In FIGS. 2 to 4, the transfer unit Ub of the first embodiment has a frame plate 17 extending in the left-right direction as an example of the frame portion. The paper guide 16 is integrally formed on the front side of the frame plate 17. Pressing guides 18 as an example of pressing guides are formed on the left and right ends of the frame plate 17. The pressing guide 18 supports a bearing member 21 that rotatably supports the rotating shafts 19 at both ends of the transfer roll Tr. The bearing member 21 is supported so that the transfer roll Tr can move in the direction of approaching and separating from the photoconductor PR. Further, in the state where the transfer unit Ub is mounted on the printer main body U1, the position of the bearing member 21 is set so that the bearing member 21 is pushed by the pressing member 11 in the direction toward the photoconductor PR.

At the rear end of the frame plate 17, a rear end portion 22 is formed as an example of the positioned portion. The tip of the rear end portion 22 is formed in an arc shape corresponding to the folded portion 7. The transfer unit Ub of the first embodiment is rotatably supported by the arcuate portion of the folded portion 7 and the rear end portion 22 in a state where the rear end portion 22 is abutted against the folded portion 7.
Locks 26 as an example of the regulated portion are supported on the left and right ends of the front portion of the frame plate 17. The lock 26 is arranged at a position corresponding to the hook 12. The lock 26 has a pillar portion 26a extending upward. An upper arm 26b is formed at the upper end of the pillar portion 26a, and a lower arm 26c is formed below the upper arm 26b. Each arm 26b, 26c is configured to be elastically deformable with a connecting portion with the pillar portion 26a as a fulcrum.

The upper arm 26b is formed so as to extend along the upper surface of the front protrusion 12d of the hook 12 in the natural length state in which the hook 12 is not elastically deformed. At the rear end of the upper arm 26b, an upper claw portion 26d is formed at a position corresponding to the step portion 12c of the hook 12. The upper claw portion 26d is formed in a shape bent downward so as to be caught by the step portion 12c in a natural length state.
The lower arm 26c is formed so as to extend forward along the lower end of the lower protrusion 12e of the hook 12 in the natural length state. A lower claw portion 26e is formed at the rear end of the lower arm 26c. The lower claw portion 26e is formed in a shape bent upward so as to be hooked on the front side of the lower protrusion portion 12e in a natural length state.

(Action of Example 1)
In the printer U of the first embodiment having the above configuration, the transfer unit Ub and the process unit Ua are mounted on the printer main body U1 in a state where printing is performed. Therefore, when the transfer unit Ub is attached, the lock 26 shown in FIG. 4A has a natural length. In this state, the claw portions 26d and 26e hang on the stepped portion 12c and the lower protrusion portion 12e. Therefore, the transfer unit Ub is supported in a state of being positioned on the printer main body U1. In this state, the transfer unit Ub is abutted against the folded-back portion 7 of the rear end portion 22, and the movement of the transfer unit Ub on the downstream side in the mounting direction is restricted.

Further, the movement of the transfer unit Ub on the upstream side in the mounting direction is restricted by catching the claw portions 26d and 26e with the stepped portion 12c and the lower protrusion portion 12e. Further, the contact of the lower arm 26c and the lower claw portion 26e with the lower protrusion portion 12e also restricts the movement of the transfer unit Ub in the direction approaching the photoconductor PR, that is, in the pressing direction. Therefore, the lock 26 regulates the movement of the transfer unit Ub to the upstream side in the mounting direction and the movement in the pressing direction.
In particular, the transfer unit Ub of the first embodiment is pressed toward the photoconductor PR side by the pressing member 11 between the rear end portion 22 and the lock 26 in the attachment / detachment direction of the transfer unit Ub. Therefore, the transfer unit Ub is pushed toward the photoconductor PR side by the pressing member 11 with the rear end portion 22 as the center of rotation, and the lower arm 26c and the lower claw portion 26e are pressed against the lower protrusion portion 12e. Therefore, even if the transfer unit Ub or the transfer unit support member 6 is loose or the like, the lower arm 26c and the lower claw portion 26e are more stable in the lower protrusion 12e in the pressing member 11 than in the case where the pressing member 11 is not pressed. It is easy to be pressed, and the rattling of the transfer unit Ub is suppressed.
The direction of the transfer unit Ub away from the photoconductor PR is regulated by the transfer unit support plate 6.

Then, when the process unit Ua, the toner cartridge TC, and the transfer unit Ub are inspected or replaced, the front cover U1a is opened. Then, the process unit Ua and the toner cartridge TC are attached and detached through the unit attachment / detachment space 1. At this time, the process unit Ua can be attached / detached by being pulled out by an operator in an oblique direction along the unit attachment / detachment space 1. In the first embodiment, except for the rattling, the process cartridge Ua is moved in the direction in which the photoconductor PR is separated from the transfer roll Tr, and then the process cartridge Ua is moved in the direction along the unit attachment / detachment space 1. However, it can be attached and detached by the operator pulling it out in one diagonal direction.

When the transfer unit Ub is attached / detached, the operator puts his / her hand in the unit attachment / detachment space 1 with the process cartridge Ua removed, and the operator pinches the front side of the upper and lower arms 26b and 26c with his / her fingers. Then, the arms 26b and 26c are elastically deformed, and the claw portions 26d and 26e are separated from the hook 12. Therefore, the lock of the lock 26 is released. Then, the transfer unit Ub can be removed from the printer main body U1 by pulling it out in an oblique direction along the unit attachment / detachment space 1 while holding the arms 26b and 26c. Therefore, similarly to the process cartridge Ua, the transfer unit Ub does not need to be moved in two steps such as moving in the direction approaching the photoconductor PR and then moving along the unit attachment / detachment space 1, so that the operator can move diagonally. It can be attached and detached by moving it in the direction. Therefore, the transfer unit Ub can be easily attached and detached as compared with the case where two-step movement is required.

In particular, when the printer U is miniaturized, the unit attachment / detachment space 1 can only secure a narrow space. Therefore, in the configuration requiring two-step movement, it is necessary to work in the narrow unit attachment / detachment space 1, and there is a problem that the workability is deteriorated. On the other hand, in the first embodiment, the process unit Ua and the transfer unit Ub can be attached and detached by moving in one direction, which improves workability.

Further, as in the configuration described in Patent Document 1, in the configuration in which the opening / closing mechanism of the cover is separately provided in order to attach / detach the process unit and the transfer unit, there is a problem that the number of parts increases. In particular, when the image forming apparatus is miniaturized, the portion where the cover is provided may be limited. It may also be necessary to reduce the number of covers from the perspective of reducing manufacturing costs. On the other hand, in the first embodiment, the process cartridge Ua and the transfer unit Ub can be attached and detached by opening the front cover U1a, and the cover can be increased and the manufacturing cost can be reduced as compared with the conventional case. Further, in the first embodiment, the process cartridge Ua, the transfer unit Ub, and the toner cartridge TC are attached and detached through the common unit attachment / detachment space 1. Therefore, as compared with the configuration described in Patent Document 1 in which the attachment / detachment mechanism and the space are separately provided, the attachment / detachment mechanism and the attachment / detachment space can be reduced, and the cost can be reduced and the size can be reduced.

Further, in the configuration described in Patent Document 2, the process unit cannot be removed unless the transfer unit is rotated to unlock the photoconductor after the cover is opened. That is, the transfer unit cannot be removed simply by opening the cover, and two steps, that is, a step of rotating the transfer unit and a step of removing the cover, that is, two steps of movement are required. On the other hand, as described above, in the printer U of the first embodiment, the transfer unit Ub can be attached and detached by moving in one direction, and the workability is improved.

Further, as in the configuration described in Patent Documents 1 and 2, a C-shaped transport path is adopted, which is a path in which the recording sheet S is fed backward, transported upward, and discharged forward. .. In particular, in Patent Document 2 having a C-shaped transport path, the cover for exchanging the transfer unit is arranged on the rear surface of the image forming apparatus. Therefore, in order to perform the work of replacing the transfer unit on the rear surface, the work becomes troublesome. When the side with the cover is on the front side, there is a problem that the drawer of the paper feed tray is rearward or the paper is discharged backward to the discharge tray, making it difficult to take out.
On the other hand, in the printer U of the first embodiment, the trajectory of the recording sheet S as a whole is conveyed so that the paper feed tray TR1 can be pulled out forward and the recording sheet S is discharged forward to the discharge tray TRh. The transport path SH of the recording sheet S is formed so as to have a substantially S shape. Therefore, in the printer U1 of the first embodiment, the process unit Ua and the transfer unit Ub are also configured to be detachable from the front through the front cover U1a. Therefore, most of the work can be done from the front, and the workability is improved. Further, in the first embodiment, there is no cover whose upper side is opened, which is represented by the portion of the discharge tray TRh, and the number of covers is also reduced.

Here, in the image forming apparatus, the frequency of exchanging the latent image forming apparatus, the register roll, and the fixing apparatus is generally lower than that of the process unit and the transfer unit. In particular, in a configuration having an S-shaped transport path SH like the printer U of the first embodiment, a photoconductor is compared with an image forming apparatus having a C-shaped transport path as described in Patent Documents 1 and 2. The space for attaching and detaching the PR and transfer roll Tr is limited. In particular, as the image forming apparatus becomes smaller, the tendency for space to be limited becomes even stronger. The unit attachment / detachment space 1 of the first embodiment is formed by the latent image forming apparatus LH and the register roll Rr so as to avoid the latent image forming apparatus LH, the register roll Rr, and the fixing device F, which are exchanged less frequently than the process unit Ua and the transfer unit Ub. It is set in the position between. Therefore, it is not necessary to remove the latent image forming apparatus LH or the like when inspecting or replacing the transfer unit Ub or the like. Therefore, the replacement work becomes easy. Further, it is conceivable that the latent image forming apparatus LH or the like can be integrally exchanged with the process unit Ua, but in this case, there is a problem that the price of the process unit Ua increases. Therefore, in the printer U of the first embodiment, an increase in the price of the process unit Ua and the like is suppressed.

Further, in the transfer unit Ub of the first embodiment, the movement is restricted by the lock 26 and the hook 12 when the transfer unit Ub is attached to the printer main body U1. Therefore, the misalignment of the transfer roll Tr and the paper guide 16 is reduced as compared with the case where the movement is not regulated. Therefore, the occurrence of transfer defects and paper jams is suppressed.
Further, in the transfer unit Ub of the first embodiment, when the lock 26 is operated, the arms 26b and 26c move from the restricted position shown in FIG. 4A to the released position shown in FIG. 4B, and the movement restriction (lock) is released. NS. Therefore, the lock can be released with a simple operation.
Further, in the transfer unit Ub of the first embodiment, when the lock is released, the transfer unit Ub is rotated around the folded-back portion 7 and the rear end portion 22 by the force of the pressing member 11 as shown in FIG. 4B. Therefore, the transfer unit Ub is pushed up so as to float. Therefore, the force of the pressing member 11 assists the removal of the transfer unit Ub, and the workability of the removal work is improved as compared with the case where the transfer unit Ub is not pushed up.

Further, the transfer unit Ub of Example 1 has a transfer roll Tr and a paper guide 16. Therefore, when the transfer roll Tr and the paper guide 16 are separate units, misalignment may occur, but in the first embodiment, the misalignment is prevented. Further, the paper guide 16 is close to the transfer region Q4, and is easily worn by rubbing against the recording sheet S or contaminated with a developing agent or paper dust. Therefore, in recent image forming apparatus, the frequency of replacing the paper guide 16 is increasing. In the first embodiment, the paper guide 16 can be replaced together with the transfer unit Ub, and it is possible to cope with an increase in the frequency of replacement of the paper guide 16.
Further, in the transfer unit Ub of the first embodiment, the downstream end 16a of the paper guide 16 extends toward the photoconductor PR side from the tangent line L1 of the transfer region Q4. Therefore, the recording sheet S is guided so as to come into contact with the surface of the photoconductor PR on the upstream side of the transfer region Q4. Therefore, when the recording sheet S comes into contact with the transfer roll Tr first, the toner may scatter due to the discharge in the transfer region Q4, and an image defect may occur, but this is suppressed in the first embodiment.

Next, a second embodiment of the present invention will be described. In the second embodiment, the components corresponding to the components of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. do.
This embodiment differs from the first embodiment in the following points, but is configured in the same manner as the first embodiment in other respects.
FIG. 5 is an explanatory diagram of the second embodiment and is a diagram corresponding to FIG. 2 of the first embodiment.
In FIG. 5, the printer U of the second embodiment is not provided with the hook 12 of the first embodiment, but is provided with a lock 31 as an example of the regulated portion instead of the lock 26. The lock 31 of the second embodiment is configured to be in contact with the lower surface of the developing container V as an example of the regulating unit.

(Action of Example 2)
In the printer U of the second embodiment having the above configuration, when the process unit Ua is mounted, the transfer unit Ub is positioned so that the lock 31 is pushed to the developing container V of the process unit Ua, and the position is restricted. Will be done. Therefore, in the printer U of the second embodiment, the transfer unit Ub can be attached / detached without performing the operation of releasing the lock.

(Change example)
Although the examples of the present invention have been described in detail above, the present invention is not limited to the above-mentioned examples, and various modifications are made within the scope of the gist of the present invention described in the claims. It is possible. Examples of modifications (H01) to (H010) of the present invention are illustrated below.
(H01) In the above embodiment, the printer U as an example of the image forming apparatus has been illustrated, but the present invention is not limited to this, and the printer U is composed of, for example, a copying machine, a fax machine, or a multifunction device having a plurality or all of these functions. It is also possible to do.

(H02) In the above embodiment, the printer U illustrates a configuration in which a monochromatic developer is used, but the present invention is not limited to this, and can be applied to, for example, a multicolor image forming apparatus having two or more colors. ..
(H03) In the above embodiment, it is desirable, but not limited to, a configuration in which the transfer unit Ub is pushed up by the pressing member 11. For example, the pressing member 11 may also be built in the transfer unit Ub.
(H04) In the first embodiment, a configuration in which the lock 26 and the hook 12 regulate the movement of the transfer unit in the mounting direction and in the direction approaching the photoconductor PR has been illustrated, but the present invention is not limited to this. It is also possible to separately provide a member that regulates the movement of the transfer unit in the mounting direction and a member that regulates the movement of the transfer unit in the direction approaching the photoconductor PR.

(H05) In the above embodiment, the transfer unit Ub exemplifies a configuration in which the transfer unit Ub is rotatably supported around the rear end portion 22, but is not limited thereto. It is also possible to make it non-rotatable by simply hitting it.
(H06) In the above embodiment, the lock 26 exemplifies a configuration in which the regulated position and the released position are moved by elastic deformation, but the present invention is not limited to this. It is also possible to combine a rotating shaft, a spring, a gear, and the like.
(H07) In the above embodiment, the unlocking of the lock 26 is not limited to the configuration in which the operator manually performs the lock 26. For example, it is possible to use a drive source such as a motor or a solenoid to move the lock 26.

(H08) In the above embodiment, the configuration in which the transfer unit Ub has the paper guide 16 is illustrated, but the present invention is not limited thereto. It is also possible that the transfer unit Ub does not have the paper guide 16. Further, the transfer unit Ub may have another member, for example, a static elimination member, in addition to the paper guide 16.
(H09) In the above embodiment, it is desirable that the downstream end 16a of the paper guide 16 is arranged on the photoconductor PR side of the tangent line L1, but it is also possible that the transfer roll Tr side is arranged on the transfer roll Tr side of the tangent line L1. be.
(H010) In the above embodiment, the shapes of the lock 26 and the hook 12 are not limited to the shapes exemplified in the examples, and any movement in the mounting direction of the transfer unit and the direction approaching the photoconductor PR can be regulated. It can be shaped. For example, it is possible to have a shape in which the rear protrusion 12b is not provided. Further, for example, if the rear end portion 22 and the folded portion 7 can be positioned and regulated in the vertical and horizontal directions, the claw portion 26d can be omitted.

1 ... Passing part,
7 ... Positioning part,
11 ... Pressing member,
12, V ... Regulatory Department,
16 ... Guide member,
16a ... Downstream end of guide member,
26, 31 ... Controlled part,
L1 ... Tangent of transfer member,
PR ... Image holder,
Q4 ... Transcription area,
S ... medium,
Tr ... Transfer member,
U ... Image forming device,
U1 ... The main body of the image forming apparatus,
Ua ... Image holder unit,
Ub ... Transfer unit.

Claims (7)

An image holder unit that includes an image holder and is detachably supported with respect to the main body of the image forming apparatus.
A transfer unit that is arranged to face the image holder in a transfer region and includes a transfer member that transfers an image of the surface of the image holder to a medium and is detachably supported by the main body of the image forming apparatus.
The main body of the image forming apparatus is composed of a space extending obliquely with respect to a first direction connecting the image holder and the rotation axes of the transfer member when viewed in the rotation axis direction of the transfer member or the image holder. With respect to the passing portion through which the image holder unit is attached and detached,
A transfer unit that moves in only one diagonal direction through the passing portion and is detachably supported with respect to the main body of the image forming apparatus.
A pressing member that is supported by the main body of the image forming apparatus and presses the transfer unit toward the image holder.
A positioning unit that is arranged in the main body of the image forming apparatus, is arranged downstream of the transfer unit mounting direction and downstream of the transfer region with respect to the medium transport direction, and positions the transfer unit.
A regulating unit that is arranged upstream of the transfer unit mounting direction and upstream of the transfer region with respect to the medium transport direction and regulates the movement of the transfer unit in the pressing direction by the pressing member.
A regulated portion that can move between a regulated position that comes into contact with the regulated portion and restricts the movement of the transfer member and a released position that is released from contact with the regulated portion and the regulation is released. With the transfer unit having
Equipped with a,
When the regulated portion moves to the release position, the transfer unit moves by the force of the pressing member toward the image holder and toward the removal side of the passing portion.
An image forming apparatus comprising and this. The regulating unit, which regulates the movement of the transfer unit in the mounting direction to the upstream side and also regulates the movement in the pressing direction.
The image forming apparatus according to claim 1 , wherein the image forming apparatus is provided. The transfer unit, which is rotatably supported in the direction of approaching and separating from the image holder with the positioning portion as the center of rotation.
The image forming apparatus according to claim 1 , wherein the image forming apparatus is provided. The regulated portion, which can be moved from the regulated position to the released position according to the operation of the operator.
The image forming apparatus according to claim 1 , wherein the image forming apparatus is provided. The image having the restricting portion, which, when the image holder unit is attached to the main body of the image forming apparatus, comes into contact with the regulated portion provided in the transfer unit and restricts the movement of the transfer unit. holder unit,
The image forming apparatus according to any one of claims 1 to 4 , wherein the image forming apparatus is provided. The transfer unit having a guide member for guiding the medium,
The image forming apparatus according to any one of claims 1 to 5 , wherein the image forming apparatus is provided. The guide member arranged on the upstream side of the transfer region, wherein the downstream end of the guide member projects toward the image holder side from the tangent line of the transfer member in the transfer region.
The image forming apparatus according to claim 6 , wherein the image forming apparatus is provided.

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