Image forming device

Abstract

To provide an image forming apparatus that allows insertion and withdrawal of a process unit, the image forming apparatus simplifying the procedure of taking out the process unit from an image forming apparatus main body and achieving low cost and miniaturization.SOLUTION: An image forming apparatus comprises: an apparatus main body; a removable unit (process unit 5) that is removably attached to the apparatus main body and includes an image carrier capable of carrying an image; a transfer member (transfer roller 11) that is provided contactable and separable with respect to the image carrier; unit-side guide parts (PCU-side guides 29) that are provided on the removable unit and regulate the position of the transfer member with respect to the image carrier; main body-side guide parts (main body-side guides 30) that are provided on the apparatus main body for guiding the transfer member to the unit-side guide parts; and moving means that allows the transfer member to move between the unit-side guide parts and the main body-side guide parts.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] It is already known that when a process unit including a toner carrier is pulled out from the front side of an image forming apparatus, a transfer roller unit is separated from the process unit. For example, Patent Document 1 discloses a configuration that can move a transfer roller away from a photosensitive drum and accurately position the transfer roller. However, when inserting or removing a process unit, the transfer roller needs to be moved away from the insertion / removal path, which increases the amount of separation, making it difficult to reduce the size of the device.

[0003] Also, Patent Document 2 discloses a configuration in which a transfer roller and a paper transport guide upstream and downstream of the transfer roller are used as a transfer unit, and a positioning member is provided in the device body or the intermediate transfer unit. However, in a configuration in which a positioning member is provided in the device body, there is a problem that the guide shape of the device body may come into contact with the process unit or the toner image carrier when inserting or removing the process unit, which increases costs due to the addition of a cover member or the use of high-precision parts. In addition, in a configuration in which a positioning member is provided in the intermediate transfer unit, there is a problem that the amount of separation is large in order to move the transfer roller away from the insertion and removal trajectory of the process unit. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to simplify the procedure for removing a process unit from the main body of an image forming apparatus into which a process unit is inserted and removed, thereby achieving low cost and compactness. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, an image forming apparatus according to the present invention comprises: A device body, a removable unit that is removable from the main body of the apparatus and includes an image carrier that is capable of carrying an image; a transfer member provided so as to be movable toward and away from the image carrier; a unit side guide portion provided in the removable unit and configured to regulate a position of the transfer member relative to the image carrier; a main body side guide portion provided in the apparatus main body for guiding the transfer member to the unit side guide portion; a moving means for moving the transfer member between the unit side guide portion and the main body side guide portion; 、 The transfer member is positioned on the main body guide portion when the detachable unit is attached or detached. It is characterized by: Effect of the Invention

[0006] According to the present invention, in an image forming apparatus into which a process unit is inserted and removed, the procedure for removing the process unit from the main body of the image forming apparatus can be simplified, thereby realizing low cost and miniaturization. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an image forming apparatus according to an embodiment. [Diagram 2] 2 is a diagram illustrating the image forming apparatus of FIG. 1 in a state where the main body opening / closing bar is open. FIG. [Diagram 3] FIG. 2 is a diagram illustrating an example of the configuration of a process unit. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a transfer unit. [Diagram 5] 5A and 5B are diagrams illustrating an example of a contact / separation mechanism for a transfer roller. [Figure 6] 1A and 1B are diagrams illustrating an example of insertion and removal of a process unit, opening and closing of a transfer unit, and a peripheral layout. [Figure 7] 11A and 11B are diagrams illustrating an example of a guide for a transfer roller shaft of an image forming apparatus in a comparative example. [Figure 8]11 is a diagram illustrating a comparative example in which a guide for a transfer roller shaft is provided in the image forming apparatus main body. [Figure 9] 5A and 5B are diagrams illustrating examples of shapes of guides for a transfer roller shaft of an image forming apparatus according to an embodiment. [Figure 10] 13A and 13B are diagrams illustrating a state in which the position of the transfer roller shaft is regulated by a PCU-side guide. [Figure 11] 13 is a diagram illustrating a state in which the transfer roller has moved to a main body side guide. FIG. [Figure 12] 13A and 13B are diagrams illustrating an example of a configuration in which the gap between the guides is larger than the outer diameter of the transfer roller shaft. [Figure 13] FIG. 1 is a diagram illustrating an example of the configuration of an image forming apparatus using an intermediate transfer method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In each of the drawings for explaining the embodiment of the present invention, components such as members and components having the same function or shape are denoted by the same reference numerals as far as they can be distinguished, and the description thereof will be omitted after the first description.

[0009] The present invention is characterized in that, when a process unit (process cartridge) having an image carrier is removed from the front of the image forming apparatus, the transfer roller is moved to a main body guide provided on the main body side when it is separated from the photosensitive body, thereby moving the transfer roller out of the insertion / removal trajectory of the process unit.

[0010] In order to realize this feature, the image forming apparatus of one embodiment is configured to include, for example, an image forming apparatus main body (printer) 14, a removable unit (process unit 5) that is removable from the apparatus main body and includes an image carrier (e.g., a photoconductor or a transfer belt) that can carry an image, a transfer member (transfer roller 11) that is provided so as to be movable toward and away from the image carrier, a unit side guide portion (PCU side guide 29) that is provided in the removable unit and that regulates the position of the transfer member relative to the image carrier, a main body side guide portion (main body side guide 30) that is provided in the apparatus main body and that guides the transfer member to the unit side guide portion, and a moving means (contact / separation lever 20, operating lever 21, transfer roller unit 23, etc.) that allows the transfer member to move between the unit side guide portion and the main body side guide portion. Note that the parentheses indicate the correspondence between the configurations shown in Figures 1 to 6 as an example.

[0011] In this way, the amount of movement of the transfer member from the insertion / removal trajectory of the removable unit can be reduced when the removable unit is attached / detached. Furthermore, by providing a unit-side guide section and a main body-side guide section, the dimensions of the unit-side guide section, which requires precision, can be optimized, resulting in reduced costs. The above-described embodiments of the present invention will be described in detail with reference to the following drawings.

[0012] First, an example of the overall configuration of the image forming apparatus will be described. 1 and 2 are diagrams for explaining an example of the configuration of an image forming apparatus according to an embodiment. FIG. 1 shows a state in which the main body opening / closing cover is closed, and FIG. 2 shows a state in which the main body opening / closing bar is open. In Figures 1 and 2, reference numeral 14 denotes a printer serving as the image forming apparatus main body (apparatus main body), 5 denotes a process unit (imaging section) that forms a toner image (image) on the photosensitive drum 1, 17 denotes an exposure section (writing section) that irradiates the photosensitive drum 1 with exposure light based on image information input from an input device such as a personal computer, 11 denotes a transfer roller (transfer member) that transfers the toner image formed on the photosensitive drum 1 to a recording medium 7, 7 denotes a recording medium such as transfer paper, 12 denotes a fixing device that fixes an unfixed image on the recording medium 7, and 10 denotes a registration roller (timing roller) that transports the recording medium 7 toward the transfer roller 11.

[0013] Here, the process unit 5 is configured as a unit integrally including a photoconductor drum 1 as an image carrier capable of carrying an image, a charging section 3 (charging roller), a developing section 4 (developing device), and a cleaning section 2 (cleaning device). The process unit 5 is an example of the above-mentioned detachable unit, and is installed detachably (replaceably) with respect to the image forming apparatus main body 14.

[0014] More specifically, the photoconductor drum 1 as an image carrier is a negatively charged organic photoconductor, and is configured by providing a photosensitive layer and the like on a drum-shaped conductive support. Although not shown, the photoconductor drum 1 is configured by sequentially laminating an undercoat layer as an insulating layer, a charge generating layer as a photosensitive layer, and a charge transport layer as a photosensitive layer on a conductive support as a base layer. The photoconductor drum 1 is rotated counterclockwise in FIG. 1 by a drive motor (not shown).

[0015] The main body opening / closing cover 15 is provided so as to be rotatable around a rotation fulcrum 16. The transfer roller 11, a part of the registration roller 10, etc. are provided in a transfer unit 24, and are provided so as to be rotatable around a rotation shaft 22. The transfer roller 11 is an example of a transfer member provided so as to be capable of approaching and releasably moving towards an image carrier.

[0016] Next, the process unit and the transfer unit will be described in detail with reference to FIGS. FIG. 3 is a diagram illustrating an example of the configuration of the process unit. FIG. 4 is a diagram illustrating an example of the configuration of the transfer unit. FIG. 5 is a diagram illustrating an example of a contact / separation mechanism for the transfer roller. FIG. 6 is a diagram for explaining an example of insertion and removal of a process unit, opening and closing of a transfer unit, and a peripheral layout.

[0017] An example of the configuration of the process unit 5 will be described with reference to FIG. The process unit 5 has a configuration in which the photosensitive drum 1 is sandwiched between two process unit face plates 18. Each of the two process unit face plates 18 is provided with a PCU (process unit) side guide 29 for the transfer roller shaft 19 for determining the position of the transfer roller 11 when it comes into contact with the photosensitive drum 1. Therefore, when the transfer roller 11 is in contact with the photosensitive drum 1, the transfer roller 11 is also sandwiched between the two process unit face plates 18. The process unit 5 is provided inside the image forming apparatus main body 14 so as to be insertable and removable, and the inserting and removing direction is the axial direction of the photosensitive drum 1 .

[0018] The positions of the transfer roller 11 and the photosensitive drum 1 are determined by the following two configurations. The first is the circumferential direction, which is determined by the PCU side guide 29 . The second is the center distance, which is determined by the balance between the hardness of the transfer roller 11 and the pressure of the contact / separation lever 20 when the photosensitive drum 1 is considered to be a rigid body. Alternatively, a roller with an outer diameter smaller than the outer diameter of the transfer roller is provided on the transfer roller shaft 19, and this is brought into contact with the surface of the photosensitive drum 1.

[0019] An example of the configuration of the transfer unit 24 will be described with reference to FIG. The transfer unit 24 is provided with a detachable transfer roller unit 23 to which the transfer roller 11 is attached. The transfer unit 24 is sandwiched between main body side plates 26 shown in Fig. 6. The main body side plates 26 hold the transfer unit 24 on a rotating support shaft 22 when the transfer unit 24 is opened or closed. The transfer roller 11 is moved by a contact / separation mechanism, with the transfer roller shaft 19 being guided by a PCU side guide 29 and a main body side guide 30, which will be described later. The contact / separation mechanism of the transfer roller 11 will be described with reference to FIG. 5, and the opening / closing mechanism of the transfer unit 24 will be described with reference to FIG.

[0020] 5, an example of a mechanism for moving the transfer roller 11 toward and away from the photosensitive drum 1 will be described. The transfer roller 11 is pressed against the photosensitive drum 1 as shown in FIG. The contact / separation mechanism is configured to dispose the transfer roller 11 in a direction that moves it away from the photosensitive drum 1 due to its own weight. The contact / separation mechanism moves the transfer roller 11 by at least a transfer roller unit 23 in which the transfer roller 11 is provided, a contact / separation lever 20, and a movable lever 21. The contact / separation lever 20 presses the transfer roller unit 23 with a spring so that a force is applied in a contact / separation lever pressure direction 25. On the other hand, the movable lever 21 displaces the contact / separation lever 20 in a direction opposite to the contact / separation lever pressure direction 25. The contact / separation mechanism is a mechanism for pressing the transfer roller 11 in a contact / separation lever pressure direction 25 via a contact / separation lever 20 and operating an operating lever 21 to contact or separate the transfer roller 11 from the photosensitive drum 1 .

[0021] The insertion and removal of the process unit 5 and the opening and closing of the transfer unit 24 will be described with reference to FIG. The process unit 5 is provided so as to be insertable and removable in the axial direction of the photosensitive drum 1 with respect to the image forming apparatus main body, that is, in the direction of the arrow 28. The transfer unit 24 has rotating support shafts 22 for opening and closing the transfer unit provided on both sides thereof held by main body side plates 26, and is provided so as to be openable and closable in the direction of the arrow 27 around the rotating support shafts 22.

[0022] In addition, the opening of the main body side guide 30 of the transfer roller shaft 19 provided on the main body side plate 26 and the opening of the PCU side guide 29 of the transfer roller shaft 19 provided on the process unit face plate 18 are arranged so as to intersect with the trajectory of the transfer roller shaft 19 that accompanies the rotational trajectory of the transfer unit 24.

[0023] Next, the shapes of the PCU side guide 29 and the main body side guide 30 of the transfer roller shaft 19 shown in FIG. 6 will be described in detail. First, the configuration and problems of the comparative example will be described with reference to FIGS. In the conventional structure where the process unit is pulled out from the main body of the device, the transfer roller unit is provided on the side of the device to bring the transfer roller close to the photosensitive member, and a positioning shape is provided on the face plate of the process unit. However, because the face plate of the process unit also has a shape for guiding the transfer roller to the position when the side cover of the device is closed, there was a problem that the amount of separation was large and it was not possible to make the device compact.

[0024] 7 is a diagram for explaining an example of a guide for a transfer roller shaft of an image forming apparatus of a comparative example, in which an example of the positions of transfer roller 11 and transfer roller shaft 19 are indicated by dashed lines. The guide 29P for the transfer roller shaft 19 provided on the process unit face plate 18 can be divided into two functional parts. Specifically, it is a receiving opening 29P-1 for the transfer roller shaft 19 that approaches as the transfer unit 24 opens and closes, and a position regulating portion 29P-2 that brings the transfer roller 11 and the photosensitive drum 1 into contact with each other. In this configuration, when attempting to insert or remove the process unit 5 from the image forming apparatus body 14, the transfer roller 11 must be moved to the outside of the insertion / removal path of the process unit 5, that is, beyond the guide 29P of the transfer roller shaft 19.

[0025] In detail, even when the transfer roller 11 is separated from the photosensitive drum 1, it remains in contact with the position regulating portion 29P-2 that determines the contact angle of the transfer roller 11. Since the guides 29P are all disposed inside the process unit 5, they interfere with the transfer roller unit 23 even if one tries to pull out the process unit 5. Therefore, in order to pull out the process unit 5 from the front of the device, it is necessary to open the cover on the side of the device and move the transfer unit 24 aside as shown in FIG. Therefore, in order to increase the amount of movement by the aforementioned contact / separation mechanism, it is necessary to increase the size of the peripheral components and the image forming apparatus main body 14, or to increase the number of work steps for opening the transfer unit 24.

[0026] Next, a comparative example in which a guide for the transfer roller shaft 19 is provided only on the main body of the image forming apparatus will be described. Fig. 8 is a diagram illustrating a comparative example in which a guide for the transfer roller shaft is provided on the image forming apparatus main body. The guide 30P for the transfer roller shaft 19 is provided on the main body side plate 26 shown in Fig. 6. In Fig. 8, an example of the positions of the transfer roller 11 and the transfer roller shaft 19 is shown by dashed lines. The advantage of this case is that the amount of displacement of the transfer roller 11 is minimal when inserting or removing the process unit 5. However, since the guide shape of the process unit face plate 18 is eliminated, the process unit 5 is more likely to come into contact with the photoconductor drum 1 when it is inserted, removed, or carried, so a photoconductor protective cover part (not shown) is required.

[0027] Also, the guide 30P of the transfer roller shaft 19 will function as the position regulating portion 29P-2 shown in Fig. 7. For this reason, if the position regulating function is provided on the main body side plate 26 side, the number of piled up parts related to the position tolerance of the photosensitive drum 1 and the transfer roller 11 will increase, and it will be necessary to use parts with higher precision than in the current configuration, resulting in increased costs.

[0028] In order to solve the problems described with reference to FIGS. 7 and 8, in one embodiment, the transfer roller shaft 19 is guided by a PCU side guide 29 and a main body side guide 30. In the embodiment shown in FIG. FIG. 9 is a diagram illustrating an example of the shape of a guide for a transfer roller shaft of an image forming apparatus according to an embodiment. In one embodiment of the present invention, of the guide shapes of the transfer roller shaft 19, a PCU side guide 29 that functions as a position regulating section 29P-2 that requires high precision is provided on the process unit panel 18, and a main body side guide 30 that functions as a receiving port 29P-1 that may have relatively low precision is provided on the main body side panel 26 (see Figure 6).

[0029] The PCU side guide 29 is an example of the unit side guide portion described above, and the main body side guide 30 is an example of the main body side guide portion described above. By making the gap (distance) 31 between the PCU side guide 29 and the main body side guide 30 smaller than the outer diameter of the transfer roller shaft 19 being guided (the diameter of the portion of the transfer roller shaft 19 as a transfer member that contacts the PCU side guide 29 and the main body side guide 30), it is possible to prevent the transfer roller 11 from falling off between the guides. This allows the transfer roller 11 to be stably transferred between the PCU side guide 29 and the main body side guide 30. Here, the transfer roller shaft 19 has been used for the explanation, but it is sufficient that the outer diameter of the portion of the roller-shaped transfer member such as the transfer roller 11 that is guided in contact with the PCU side guide 29 and the main body side guide 30 is larger than the gap 31.

[0030] In addition, the movement of the transfer roller 11 between the PCU side guide 29 and the main body side guide 30 is performed by rotating the operating lever 21 by a mechanism such as a solenoid or cam at a predetermined timing after detecting the "open" of the cover that is opened to attach or detach the process unit (PCDU) 5, and moving the transfer roller 11 to the separated position. The transfer roller 11 is also moved to the separated position when a predetermined timing occurs after the power is turned OFF. The transfer roller 11 is also moved to the contact position by rotating the contact / separation lever 20 by a mechanism such as a solenoid or cam at a predetermined timing after the power is turned ON. The transfer roller 11 is positioned in the PCU side guide 29 when paper is being passed, and is positioned in the main body side guide 30 when the process unit 5 is being attached or detached.

[0031] By adopting such a configuration, the transfer roller 11 can be retracted from the insertion / removal path of the process unit 5 with a smaller approach / removal movement amount than currently used. In addition, a protective member for the photosensitive drum 1 during insertion / removal is not required. Furthermore, because the precision of parts can be optimized, it is possible to prevent an increase in parts costs due to high precision.

[0032] Fig. 10 is a diagram for explaining a state in which the position of the transfer roller shaft is regulated by the PCU side guide. Fig. 11 is a diagram for explaining a state in which the transfer roller has moved to the main body side guide. In Figs. 10 and 11, an example of the positions of the transfer roller 11 and the transfer roller shaft 19 is shown by dashed lines. 10, the position of the transfer roller shaft 19 of the transfer roller 11 is regulated by a PCU side guide 29. In detail, the position of the transfer roller shaft 19 is determined in the circumferential direction from the center of the photosensitive drum 1 by the PCU side guide 29. As described above, the center distance between the photosensitive drum 1 and the transfer roller 11 is determined by the balance between the hardness of the transfer roller and the pressure applied by the contact / separation lever 20. This state occurs when paper is passed through the transfer roller 11 or when the surface of the transfer roller 11 is subjected to bias cleaning.

[0033] 11, when the transfer roller 11 is separated from the photosensitive drum 1, it can be moved to the main body side guide 30, thereby retracting the transfer roller 11 from the insertion / removal path of the process unit 5. This allows the process unit 5 to be pulled out simply by operating the device from the front side.

[0034] Moreover, it is preferable that at least a part of the PCU side guide 29 has a shape in which the gap between the PCU side guide 29 and the transfer roller 11 becomes smaller as the PCU side guide 29 approaches the photosensitive drum 1 . Furthermore, it is preferable to make the opening (entrance side opening) of the PCU side guide 29 or the main body side guide 30 on the side where the transfer roller 11 enters wider than the opening (image carrier side opening) on ​​the photosensitive drum 1 side. In this way, the transfer roller unit 23 can be easily handed over.

[0035] On the other hand, if the gap 31 between the PCU side guide 29 and the main body side guide 30 cannot be made smaller than the outer diameter of the transfer roller shaft 19 that it guides, it is preferable to further provide an auxiliary member that assists the transfer roller 11 in moving from the PCU side guide 29 to the main body side guide 30. Fig. 12 is a diagram for explaining a configuration example in which the gap between the guides is larger than the outer diameter of the transfer roller shaft. In Fig. 12, an auxiliary member 23-1 is added to the transfer roller unit 23 that holds the transfer roller shaft 19. When the transfer roller shaft 19 approaches the gap 31, the auxiliary member 23-1 provided on the transfer roller unit 23 comes into contact with a part of the transfer unit 24 located away from the insertion / removal trajectory of the process unit 5. The auxiliary member may be formed by partially modifying the shape of the transfer roller unit 23. As a result, the movement trajectory of the transfer roller shaft 19 becomes an arc trajectory centered on the contact point between the auxiliary member 23-1 of the transfer roller unit 23 and the transfer unit 24, so that the transfer roller shaft 19 can move between the main body side guide 30 and the PCU side guide 29 without entering the guide gap 31.

[0036] In the above embodiment, the photosensitive drum 1 is used as the image carrier, and the transfer roller 11 is used as the transfer member. However, the image carrier may be an intermediate transfer belt, and the transfer member may be in the form of a belt.

[0037] The present invention can also be applied to a configuration example in which a secondary transfer roller 36 and an intermediate transfer unit 32 are combined as shown in FIG. 13. FIG. 13 is a diagram for explaining a configuration example of an image forming apparatus using an intermediate transfer method. The intermediate transfer unit 32 as a removable unit includes an intermediate transfer belt 35 as an image carrier, and support rollers 33 and 34 around which the intermediate transfer belt 35 is stretched. The transfer unit 24 includes a secondary transfer roller 36 as a transfer member. In the image forming apparatus, four photoconductor drums 1Y, 1M, 1C, and 1K corresponding to the colors of yellow (Y), magenta (M), cyan (C), and black (K) are arranged on the intermediate transfer belt 35. Toner images formed on the four photoconductor drums 1Y, 1M, 1C, and 1K are transferred to the intermediate transfer belt 35.

[0038] The invention made by the inventor has been specifically described above based on an embodiment, but it goes without saying that the present invention is not limited to the above embodiment and can be modified in various ways without departing from the gist of the invention. [Explanation of symbols]

[0039] 1 Photoconductor drum (image carrier) 5 Process unit (detachable unit) 11 Transfer roller (transfer member) 14 Printers (image forming devices) 18 Process unit face plate 19 Transfer roller shaft 20 Engagement / disengagement lever 21 Operating lever 22 Spindle 23 Transfer roller unit 23-1 Auxiliary parts 24 Transcription Unit 26 Body side panel 29 PCU side guide 29P-1 Receiving section 29P-2 Position regulation part 30 Main unit guide [Prior art documents] [Patent documents]

[0040] [Patent Document 1] JP 2006-030643 A [Patent Document 2] JP 2007-127784 A

Claims

1. A device body, a removable unit that is removable from the main body of the apparatus and includes an image carrier that is capable of carrying an image; a transfer member provided so as to be movable toward and away from the image carrier; a unit side guide portion provided in the removable unit and configured to regulate a position of the transfer member relative to the image carrier; a main body side guide portion provided in the apparatus main body for guiding the transfer member to the unit side guide portion; a moving means for moving the transfer member between the unit side guide portion and the main body side guide portion, The image forming apparatus according to claim 1, wherein the transfer member is positioned at the main body side guide portion when the detachable unit is attached or detached.

2. The unit-side guide portion has at least a part of a shape in which the gap between the unit-side guide portion and the transfer member becomes smaller as the unit-side guide portion approaches the image carrier.

2. The image forming apparatus according to claim 1,

3. The transfer member is in the form of a roller. The distance between the unit side guide portion and the main body side guide portion is smaller than the diameter of a portion of the transfer member that contacts the unit side guide portion and the main body side guide portion.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

4. 4. The image forming apparatus according to claim 3, wherein the contact portion is a shaft of the roller-shaped transfer member.

5. The transfer member is in the form of a roller. a distance between the unit-side guide portion and the body-side guide portion is equal to or greater than a diameter of a portion of the transfer member that contacts the unit-side guide portion and the body-side guide portion; The transfer member further includes an auxiliary member that assists the transfer member in moving from the unit-side guide portion to the main body-side guide portion.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

6. The image forming apparatus according to any one of claims 1 to 5, characterized in that the main body side guide portion has an entrance side opening on the side where the transfer member enters and an image carrier side opening on the side closer to the image carrier than the entrance side opening, and the opening width of the entrance side opening is wider than that of the image carrier side opening.

7. An apparatus body, a removable unit that is removable from the main body of the apparatus and includes an image carrier that is capable of carrying an image; a transfer member provided so as to be movable toward and away from the image carrier; a unit side guide portion provided in the removable unit and configured to regulate a position of the transfer member relative to the image carrier; a main body side guide portion provided in the apparatus main body for guiding the transfer member to the unit side guide portion; a moving means for moving the transfer member between the unit side guide portion and the main body side guide portion, The transfer member is in the form of a roller. an image forming apparatus, characterized in that a distance between the unit side guide portion and the main body side guide portion is smaller than a diameter of a portion of the transfer member that contacts the unit side guide portion and the main body side guide portion;

8. An apparatus body, a removable unit that is removable from the main body of the apparatus and includes an image carrier that is capable of carrying an image; a transfer member provided so as to be movable toward and away from the image carrier; a unit side guide portion provided in the removable unit and configured to regulate a position of the transfer member relative to the image carrier; a main body side guide portion provided in the apparatus main body for guiding the transfer member to the unit side guide portion; a moving means for moving the transfer member between the unit side guide portion and the main body side guide portion, The transfer member is in the form of a roller. a distance between the unit-side guide portion and the body-side guide portion is equal to or greater than a diameter of a portion of the transfer member that contacts the unit-side guide portion and the body-side guide portion; The image forming apparatus further comprises an auxiliary member that assists the transfer member in moving from the unit-side guide portion to the main body-side guide portion.

9. A device body, a removable unit that is removable from the main body of the apparatus and includes an image carrier that is capable of carrying an image; a transfer member provided so as to be movable toward and away from the image carrier; a unit side guide portion provided in the removable unit and configured to regulate a position of the transfer member relative to the image carrier; a main body side guide portion provided in the apparatus main body for guiding the transfer member to the unit side guide portion; a moving means for moving the transfer member between the unit side guide portion and the main body side guide portion, an image forming apparatus characterized in that the main body side guide portion has a shape having an entrance side opening on the side where the transfer member enters and an image carrier side opening which is closer to the image carrier than the entrance side opening, and the opening width of the entrance side opening is wider than that of the image carrier side opening.

Images