JP6942946B2 - Contact / detachment mechanism and image forming device using this - Google Patents

Description

The present invention relates to a contact / detachment mechanism and an image forming apparatus using the same.

Conventionally, the following methods are already known as a method for bringing a roll member having an elastic layer into contact with and separating a photoconductor arranged to face the elastic layer.
Patent Document 1 discloses a configuration provided with a separation cover for separating the charging roll from the photoconductor from packaging to use in order to prevent unnecessary deformation of the charging roll.
Further, in Patent Document 2, in an embodiment provided with a transfer roll provided so as to sandwich the photoconductor and a transport belt, the transfer roll is directed to a position facing the photoconductor by moving the transport belt, and is returned to the original position after stopping. The configuration is disclosed.
Further, in Patent Document 3, in an embodiment in which a helical gear and a chipped tooth gear that mesh with the drum gear of the photoconductor are used, a state of separation between the photoconductor and the charging roll is maintained by the chipped tooth gear, and the drum gear. A configuration is disclosed in which the missing tooth gear rotates due to the rotation of the missing tooth gear to form a contact state between the two, and further, the stopper member is projected by the movement of the helical gear to regulate the rotation of the missing tooth gear.

Japanese Unexamined Patent Publication No. 2007-271759 (best form for carrying out the invention, FIG. 2) Japanese Unexamined Patent Publication No. 2010-210922 (form for carrying out the invention, FIG. 6) Japanese Unexamined Patent Publication No. 2001-109356 (Example 1, FIG. 10)

The technical problem to be solved by the present invention is to bring the movable member into contact with the peripheral surface of the rotating body that can be driven and rotated by utilizing the rotational force associated with the driving rotation of the rotating body. It is to realize the separation operation.

The invention according to claim 1 is a contact / detachment mechanism for bringing a movable member into contact with and detaches from a peripheral surface of a rotating body that can be driven and rotated, and is provided on the end side in the width direction intersecting the rotation direction of the rotating body. A first drive transmission member made of a helical gear, which is driven to rotate around a center of rotation by transmitting the rotational force of the rotating body, and the first drive transmission member are provided so as to mesh with each other and rotate. When the body does not drive and rotate, it is held in a predetermined initial position, and when the rotating body drives and rotates, the rotational force of the first drive transmission member is transmitted to follow and rotate around the center of rotation and rotate. A second drive transmission member made of a helical gear that is moved toward the rotating body along the central axis direction, a contact position where the movable member contacts the peripheral surface of the rotating body, and the movable member retracts. A support member that supports the movable member so as to be detachable between the retracted positions is provided between the second drive transmission member and the support member, and the second drive transmission member is provided in the direction of the rotation center axis. When it is moved from the initial position along the above, it is displaced toward the support member along the direction of the center axis of rotation and comes into contact with the support member, and the support member approaches the peripheral surface of the rotating body. It is a contact / detachment mechanism including a displacement mechanism that pushes the movable member in a direction and displaces the movable member at the contact position.

The invention according to claim 2 is the contact / detachment mechanism according to claim 1, wherein the first drive transmission member, the second drive transmission member, the support member, and the displacement mechanism are in the rotation direction of the rotating body. It is a contact / detachment mechanism characterized in that it is provided on each end side in the width direction where it intersects .
In the invention according to claim 3 , in the contact / detachment mechanism according to claim 1 or 2, the second drive transmission member is urged to be held at the initial position when the rotating body does not drive and rotate. It is a contact / detachment mechanism characterized by including an urging member.
The invention according to claim 4 is the contact / detachment mechanism according to claim 3 , wherein the urging member is housed in the support member.
The invention according to claim 5 is the contact / detachment mechanism according to claim 1 or 2, wherein the displacement mechanism is provided separately from or integrally with the second drive transmission member and together with the second drive transmission member. An axially movable portion that moves toward the support member side along the rotation center axis direction of the second drive transmission member, and the movable member via the support member as the axially movable portion moves. A contact / separation direction movable portion that moves from the retracted position to the contact position is provided, and at least one of the axial movement portion or the contact / separation direction movable portion is directed in a direction approaching the peripheral surface of the rotating body. It is a contact / detachment mechanism characterized by having a pressing portion for pressing the support member.
The invention according to claim 6 is the contact / detachment mechanism according to claim 5 , wherein the displacement mechanism has one displacement member in which the axial movable portion and the contact / detachable movable portion are integrated, and the support thereof. The movable member is brought into contact with the movable member by guiding the movable portion in the axial direction while sliding the movable portion and bringing the pressing portion provided in the movable portion in the contact / separation direction into contact with a corner portion facing the pressing portion. It is a contact / detachment mechanism characterized by pressing the support member toward a position.
The invention according to claim 7 is the contact / detachment mechanism according to claim 5 , wherein the displacement mechanism comprises the axial movable portion and the contact / detachable movable portion as separate bodies, and the axial movable portion and the said. The contact / separation mechanism is characterized in that the pressing portion is provided at a portion where the movable portion in the contact / separation direction is engaged.
The invention according to claim 8 is the contact / detachment mechanism according to claim 1 or 2, wherein the displacement mechanism changes the support member into the movable member when the second drive transmission member returns to the initial position. It is a contact / detachment mechanism characterized by having a return mechanism for returning to the retracted position side.
In the invention according to claim 9 , in the contact / detachment mechanism according to claim 8 , the return mechanism of the displacement mechanism is arranged in parallel at a position substantially parallel to the rotation center axis of the second drive transmission member, and the second when the drive transmission member returns to the initial position, the rotation center axis of said viewed from the rotating body side second drive transmission member relative to the rotary body center axis in a direction along the width direction of said movable member It is a contact / detachment mechanism characterized in that it is arranged unevenly.
The invention according to claim 10 is the attachment / detachment mechanism according to any one of claims 1 to 9 , wherein the movable member is a rotatable rotary member, and the support member is the movable member as a rotary member. It is a contact / detachment mechanism characterized in that it is provided on a bearing that holds it rotatably.
The invention according to claim 11 comprises a latent image holder that holds an electrostatic latent image, a charger that charges the latent image holder to form an electrostatic latent image, and a static image holder. A developer that develops an electro-latent image with a developer, a transfer device that transfers an image developed by the developer and formed on the latent image holder to a recording material, and a transfer device that transfers the image to a recording material. When the latent image holder is a rotating body, and at least one of the charging device, the transfer device, and the cleaning device is a movable member, including a cleaning device for cleaning the latent image holder later. The image forming apparatus is characterized in that the contact / disconnection mechanism according to any one of claims 1 to 10 is used as the contact / disconnection mechanism between the two.

According to the invention of claim 1, in the embodiment in which the movable member is brought into contact with and detached from the peripheral surface of the rotating body that can be driven and rotated, the movement of the second drive transmitting member along the center direction of the rotation axis is simplified. In addition to the realization of the above, it is possible to realize the contact / detachment operation of the movable member by utilizing the rotational force accompanying the driving rotation of the rotating body.
According to the second aspect of the present invention, as compared with the embodiment in which the first and second drive transmission members, the support members and the displacement mechanisms are provided only on one end side in the width direction of the rotating body, the rotating body and the movable member The separation interval can be kept wide, and it can be easily applied to a movable member having a long length .
According to the invention of claim 3 , the second drive transmission member can be easily returned to the initial position.
According to the invention of claim 4 , a miniaturized contact / detachment mechanism can be realized as compared with the embodiment in which the urging member is provided outside the support member.
According to the invention of claim 5 , the displacement from the retracted position to the contact position with respect to the support member can be realized with a simple configuration.
According to the invention of claim 6 , it is possible to easily realize a displacement mechanism in which the axially movable portion and the contacting and disengaging direction movable portion are used as one displacement member.
According to the invention of claim 7 , it is possible to easily realize a displacement mechanism in which the axially movable portion and the contacting and separating direction movable portion are separate bodies.
According to the invention of claim 8 , the movable member can be retracted to the retracted position when the rotating body is not driven, regardless of the arrangement of the movable member with respect to the rotating body.
According to the invention of claim 9 , even in the embodiment in which the return mechanism of the displacement mechanism is arranged in parallel at a position substantially parallel to the second drive transmission member, the return mechanism and the support member are not enlarged. It is possible to secure the relationship with.
According to the invention of claim 10 , the movable member can be brought in and out while the rotatable movable member is rotationally held.
According to the invention of claim 11 , in the embodiment in which the movable member is brought into contact with and detached from the peripheral surface of the rotating body that can be driven and rotated, the movement of the second drive transmitting member along the center direction of the rotation axis is simplified. In addition to the realization of the above, it is possible to provide an image forming apparatus capable of realizing the contact / detachment operation of the movable member by utilizing the rotational force accompanying the driving rotation of the rotating body.

(A) is an explanatory diagram showing an outline of the contact / detachment mechanism in the outline of the embodiment according to the present invention, and (b) and (c) are explanatory views showing different aspects of the displacement mechanism. It is explanatory drawing which shows the outline of the image forming apparatus which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the mode in the retracting position of the photoconductor and the transfer roll in Embodiment 1. FIG. It is an exploded perspective view of FIG. It is explanatory drawing which shows the main part of the attachment / detachment mechanism of the transfer roll in Embodiment 1. FIG. It is explanatory drawing which shows the contact and separation state of a photoconductor and a transfer roll in Embodiment 1, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is a figure which looked at the transfer roll side from the photoconductor side in Embodiment 1, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is a perspective view which shows the contact and separation state of a photoconductor and a transfer roll in Embodiment 1, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is explanatory drawing which shows the feeding mechanism to the transfer roll used in Embodiment 1. FIG. It is sectional drawing at the position of the U groove part of the transfer housing of Embodiment 1, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is explanatory drawing which shows the main part of the contact and separation mechanism of the transfer roll in Embodiment 2, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is explanatory drawing which shows the main part of the support member and the displacement mechanism used in Embodiment 2. It is explanatory drawing which shows the contact and separation state of a photoconductor and a transfer roll in Embodiment 2, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is a figure which looked at the transfer roll side from the photoconductor side in Embodiment 2, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is a perspective view which shows the contact and separation state of a photoconductor and a transfer roll in Embodiment 2, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively. It is explanatory drawing which shows the outline of the image forming apparatus which concerns on Embodiment 3. FIG. It is explanatory drawing which shows the contact and separation state of a photoconductor and a transfer roll in Embodiment 3, (a) shows the state at the retracted position, and (b) shows the state at the contact position, respectively.

(1) Outline of the embodiment FIG. 1A is an explanatory diagram showing an outline of the contact / detachment mechanism in the outline of the embodiment according to the present invention. In the figure, the attachment / detachment mechanism is for attaching / detaching the movable member 2 to / from the peripheral surface of the rotating body 1 that can be driven and rotated, and is provided on the end side in the width direction intersecting the rotation direction of the rotating body 1. A first drive transmission member 3 made of a helical gear, which is driven by transmitting the rotational force of the rotating body 1 and rotationally driven around the center of rotation, and a first drive transmission member 3 are provided so as to mesh with each other. When the rotating body 1 does not drive and rotate, it is held at a predetermined initial position, and when the rotating body 1 drives and rotates, the rotational force of the first drive transmission member 3 is transmitted to follow and rotate around the center of rotation. A second drive transmission member 4 made of a helical gear that is moved toward the rotating body 1 along the direction of the central axis of rotation, a contact position P1 in which the movable member 2 contacts the peripheral surface of the rotating body 1, and a movable position. A second drive transmission member provided between the support member 5 that supports the movable member 2 so as to be detachable between the retracted positions P0 in which the member 2 retracts, and the second drive transmission member 4 and the support member 5. When 4 is moved from the initial position along the rotation center axis direction, it is displaced toward the support member 5 side along the rotation center axis direction and comes into contact with the support member 5, and the support member 5 is moved around the rotating body 1. It is provided with a displacement mechanism 6 that pushes the movable member 2 toward the surface and displaces the movable member 2 at the contact position P1.

Here, the rotating body 1 includes not only a drum shape but also a belt shape, and a typical mode of the movable member 2 is a rotating member, but the present invention is not limited to this, and for example, with respect to the rotating body 1. It may be a non-rotating member. Further, the first drive transmission member 3 and the second drive transmission member 4 are typically provided adjacent to each other, but the present invention is not limited to this, and other members are sandwiched between them. There is no problem.

Further, as a typical embodiment of the support member 5, a bearing in a mode in which the movable member 2 is a rotating member can be mentioned. Then, the first and second drive transmission members 3 and 4, the support member 5 and the displacement mechanism 6 may be provided on both end sides of the rotating body 1 in the width direction, respectively, or may be provided only on one side. You may. Further, the displacement mechanism 6 is composed of a plurality of members, and a part of the displacement mechanism 6 may be provided on the side of the second drive transmission member 4.

Further, if the movable member 2 can be displaced between the retracted position P0 and the contact position P1 between the rotating body 1 and the movable member 2, the rotating body 1 and the movable member 2 can be displaced at the retracted position P0. May be arranged in parallel, or the movable member 2 may be arranged obliquely with respect to the rotating body 1.

Next, a typical mode or a preferable mode of the contact / detachment mechanism in this embodiment will be described.
From the viewpoint of keeping a wide separation interval between the rotating body 1 and the movable member 2, the first drive transmission member 3, the second drive transmission member 4, the support member 5, and the displacement mechanism 6 intersect in the rotation direction of the rotating body 1. Examples thereof include modes in which both ends in the width direction are provided. For example, in the embodiment in which these members are provided only on one side of the rotating body 1 and the movable member 2, especially when the lengths of the rotating body 1 and the movable member 2 are long, the rotating body 1 and the movable member 2 at the retracted position P0 It is necessary to secure a large separation interval between the two, and the displacement amount of the movable member 2 from the retracted position P0 to the contact position P1 is increased accordingly, and the contact / separation mechanism itself is likely to be enlarged.

Further, as a mode for further simplifying the contact / disengagement mechanism, there is a mode in which the first drive transmission member 3 and the second drive transmission member 4 are composed of helical gears that mesh with each other. By engaging the two helical gears, it is easy to move in the direction along the rotation center axis (thrust direction).

Further, in order to hold the second drive transmission member 4 in the initial position, the second drive transmission member 4 is urged to be held in the initial position when the rotating body 1 does not drive and rotate. Aspects including. Such an urging member may be provided adjacent to the second drive transmission member 4, or may be provided via another member. From the viewpoint of reducing the size of the contact / detachment mechanism, the urging member may be housed in the support member 5.

Further, as a typical aspect of the displacement mechanism 6, the second drive transmission member 4 is provided separately from or integrally with the second drive transmission member 4, and together with the second drive transmission member 4, the rotation center axis direction of the second drive transmission member 4. The axially movable portion 7 that moves toward the support member 5 side along the above, and the contact / detachment direction that moves the movable member 2 from the retracted position P0 to the contact position P1 via the support member 5 as the axially movable portion 7 moves. A movable portion 8 is provided, and at least one of the axial movable portion 7 and the contact / detachment direction movable portion 8 has a pressing portion 6a for pressing the support member 5 in a direction approaching the peripheral surface of the rotating body 1. Aspects are mentioned.

Here, the axial movable portion 7 and the contact / detachable movable portion 8 may be integrally configured or may be separate bodies. That is, the configuration of the displacement mechanism 6 is not particularly limited, and for example, as shown in FIG. 1 (b), the axial movable portion 7 and the contact / detachable movable portion 8 are integrally provided, and these are integrally provided. The support member 5 may be moved, or as shown in FIG. 1 (c), the axial movable portion 7 is provided on the second drive transmission member 4 side, and the contact / detachment direction movable portion 8 is provided. It may be configured separately from the axially movable portion 7, and the axially movable portion 7 may abut against the contact and disengagement direction movable portion 8 so that the contact and disengagement direction movable portion 8 moves the support member 5.

The pressing portion 6a may be provided on either the axially movable portion 7 or the contacting / separating direction movable portion 8. Here, the pressing portion 6a has, for example, a predetermined inclined surface, but it goes without saying that the inclined direction of the inclined surface is the direction in which the support member 5 faces the contact position P1 of the movable member 2.

Further, as a typical aspect of the displacement mechanism 6, as shown in FIG. 1B, the displacement member 9 has one displacement member 9 in which the axial movable portion 7 and the contact / detachable movable portion 8 are integrated, and the support member. The movable member 2 is guided by sliding the axially movable portion 7 with respect to 5, and abutting the pressing portion 6a provided on the contacting / separating direction movable portion 8 with the corner portion facing the pressing portion 6a. An embodiment in which the support member 5 is pressed toward the contact position P1 can be mentioned. This example is an embodiment in which the axial movable portion 7 and the contact / detachable movable portion 8 are integrated into one displacement member 9, and the axial movable portion 7 slides (sliding movement) with respect to the support member 5. The support member 5 may be pressed against the contact position P1 of the movable member 2 by being guided while being guided. At this time, the axially movable portion 7 may be inserted into a guide hole provided inside the support member 5, or may cover the outside of the support member 5.
Further, as another typical aspect of the displacement mechanism 6, as shown in FIG. 1 (c), the axial movable portion 7 and the contact / detachable movable portion 8 are formed as separate bodies, and the axial movable portion 7 and the axial movable portion 7 are formed. An embodiment in which the pressing portion 6a is provided at a portion where the movable portion 8 in the contact / disengagement direction is engaged can be mentioned. In this example, the axially movable portion 7 and the contacting / separating direction movable portion 8 are separated from each other, and by providing the pressing portion 6a at the portion where the two are engaged with each other, the contacting / separating direction movable portion 8 is made of the movable member 2. It may be moved toward the contact position P1.

Further, as a typical embodiment of the displacement mechanism 6, a return mechanism for returning the support member 5 to the retracted position P0 side of the movable member 2 when the second drive transmission member 4 returns to the initial position (not shown). Aspects having the above can be mentioned. In this example, the displacement mechanism 6 is provided with a return mechanism, for example, the movable member 2 is arranged in the upper half region of the rotating body 1, and the movable member 2 moves in a direction approaching the rotating body 1 by its own weight. Even if it is, it is possible to hold the movable member 2 at the retracted position P0. Needless to say, a return mechanism may be adopted for the mode in which the movable member 2 is arranged in the lower half region of the rotating body 1.
Further, as a typical aspect of the return mechanism described above, when the second drive transmission member 4 is arranged in parallel at a position substantially parallel to the rotation center axis of the second drive transmission member 4 and the second drive transmission member 4 returns to the initial position, The rotation central axis of the second drive transmission member 4 when viewed from the rotating body 1 side may be arranged so as to be deviated from the central axis in the direction along the width direction of the rotating body 1 of the movable member 2. In this example, when the return mechanism of the displacement mechanism 6 is arranged in parallel at a position substantially parallel to the second drive transmission member 4, the second is to secure a space for the return mechanism to easily engage with the support member 5. It is preferable that the drive transmission member 4 and the movable member 2 are arranged unevenly. In this case, if the second drive transmission member 4 and the movable member 2 are not arranged unevenly, the support member 5 must be enlarged in order to secure the relationship between the return mechanism and the support member 5. There are restrictions.

Further, in the embodiment in which the movable member 2 is a rotatable rotary member, the support member 5 is provided on a bearing that rotatably holds the movable member 2 as a rotary member from the viewpoint of smoothly rotating the movable member 2. There are some aspects.

Then, in order to use the above-mentioned contact / detachment mechanism in the image forming apparatus, the following may be performed. That is, a developing agent is a latent image holder that holds an electrostatic latent image, a charger that charges the latent image holder to form an electrostatic latent image, and an electrostatic latent image on the latent image holder. A developer that develops in the above, a transfer device that transfers an image developed by the developer and formed on the latent image holder to a recording material, and the latent image retention after being transferred by the transfer device. Between both, including a cleaner for cleaning the body, when the latent image holder is a rotating body 1, and at least one of the charger, the transfer device, and the cleaner is a movable member 2. The above-mentioned one may be applied as the contact / detachment mechanism.

Here, as a specific embodiment of the image forming apparatus, the above-described contact / detachment mechanism is used with respect to an embodiment in which the rotating body 1 is a photoconductor and the movable member 2 is at least one of a charger, a transfer device, and a cleaner. Is mentioned. Further, the image forming apparatus may include a process cartridge having a charger as the movable member 2. In particular, when at least one of the rotating body 1 and the movable member 2 has an elastic layer that is elastically deformed, the elastic layer can be further suppressed from deteriorating with time by arranging them in a non-contact manner when both are unnecessary.

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the accompanying drawings.
◎ Embodiment 1
<Outline configuration of image forming apparatus>
FIG. 2 is an explanatory diagram showing an outline of the image forming apparatus according to the first embodiment. In the figure, the image forming apparatus 10 of the present embodiment has a structure of a monochrome printer, and has an image forming unit 20 for forming an image on a recording material S at substantially the center of the apparatus housing 11. A recording material supply unit 12 that supplies the recording material S toward the image forming unit 20 is installed below the image forming unit 20.

The image forming unit 20 is centered on a photoconductor 21 (corresponding to a rotating body) as a latent image holder, and various elements for forming an image are arranged around the photoconductor 21 (corresponding to a rotating body). Around the photoconductor 21, a charger 22 that charges the photoconductor 21 so that an electrostatic latent image can be formed, and an exposure device 23 for drawing an electrostatic latent image on the photoconductor 21 charged by the charger 22. , The developer 24 that develops the electrostatic latent image drawn by the exposure device 23 with a developer so as to visualize it, and transfers the developed image to the recording material S supplied from the recording material supply unit 12. A transfer device 25, a cleaner 26 for cleaning the surface of the photoconductor 21 after transfer, and the like are provided.

The recording material supply unit 12 has a supply cassette 13 in which the recording material S to be supplied is housed, and a handling mechanism 14 for separating and feeding the recording material S from the supply cassette 13 one by one. The recording materials S housed therein are appropriately fed one by one toward the image forming unit 20. The recording material S unwound from the recording material supply unit 12 is positioned by the resist roll 15 and then conveyed to the transfer site at a predetermined timing.

The image transferred onto the recording material S at the transfer site is fixed by the fixing device 16 arranged above in the apparatus housing 11, and the fixed recording material S fixed by the fixing device 16 is discharged. The roll 17 discharges the recording material to the recording material discharging portion 18 formed on the upper surface of the apparatus housing 11.

<Relationship between photoconductor and transfer device>
In the present embodiment, as shown in FIGS. 3 and 4, the photoconductor 21 has a configuration in which the photosensitive layer 21b is provided on the peripheral surface of the aluminum base tube 21a, and both ends of the aluminum base tube 21a are made of, for example, synthetic resin. Each of the flanges 32 is closed, and the support shafts 33 are arranged so as to project outward from the center of each flange 32. A bearing portion 36 is formed on the character-shaped holding arm 35, and each support shaft 33 is rotatably held by the bearing portion 36.
On the other hand, as shown in FIGS. 3 to 5, the transfer device 25 has a transfer roll 40 having a structure in which an elastic rubber having a predetermined volume resistance value is wound around a metal core bearing, and the transfer is performed. Support shafts 41 are arranged so as to protrude outward in the axial direction at both ends of the roll 40, and bearing holding portions 43 are formed on both sides of the transfer housing 42 for holding the transfer roll 40 in the axial direction. Each bearing 44 is held by the bearing holding portion 43, and each support shaft 41 is rotatably held by each bearing 44. In this example, the transfer housing 42 is fixed to a device housing or a photoconductor housing 34 (not shown), and the bearing holding portion 43 is a U-shaped groove portion (U) that opens toward the photoconductor 21 side. The groove portion) 43a is provided, and each bearing 44 can move along the depth direction of the U groove portion 43a of the bearing holding portion 43. However, each bearing 44 is position-constrained in the width direction intersecting the depth direction of the U-groove portion 43a. Reference numeral 45 is a U-shaped flange portion protruding around the bearing 44, which functions as a stopper when the bearing 44 is held in the U groove portion 43a.
Here, if the photoconductor 21 and the transfer roll 40 are placed in contact with each other for a long time, for example, a plasticizer or the like from the elastic rubber may seep out and adversely affect the photosensitive layer, or the elastic rubber may be subjected to permanent strain. May be deformed. When such a situation occurs, the conditions of the photosensitive layer 21b of the photoconductor 21 change, the transfer conditions of the transfer roll 40 change, and the image formation is adversely affected. Therefore, as a countermeasure against such a problem, in the present embodiment, the photoconductor 21 and the transfer roll 40 are brought into contact with each other when necessary, and the photoconductor 21 and the transfer roll 40 are arranged in a non-contact manner when not necessary. A contact / detachment mechanism 50 is adopted between the roll 40 and the roll 40.

<Outline of contact / detachment mechanism>
In the present embodiment, as shown in FIGS. 5 to 10, the contact / detachment mechanism 50 moves the transfer roll 40 to the contact position P1 in contact with the photoconductor 21 when the photoconductor 21 is driven and rotated, and the photoconductor 21 is driven and rotated. The transfer roll 40 is moved to the retracted position P0 retracted from the photoconductor 21 when the 21 is in the stopped state.
In this example, the contact / disengagement mechanism 50 includes a first helical gear 51 as a first drive transmission member provided coaxially with a support shaft 33 on the outer side of the flange 32 of the photoconductor 21, and the first helical gear 51. A second drive transmission member that is arranged parallel to the rotation axis of the helical gear and meshes with the first helical gear 51 to follow-rotate and move toward the end of the transfer roll 40. A support member 53 that is integrally provided with the second helical gear 52 and the bearing 44 of the transfer roll 40 and supports the bearing 44 so that the transfer roll 40 can be brought into contact with and detached from the photoconductor 21. The second helical gear 52 was provided between the second helical gear 52 and the support member 53, and was arranged at the retracted position P0 when the second helical gear 52 approached the end of the transfer roll 40. It includes a displacement mechanism 54 that displaces the transfer roll 40 toward the contact position P1.

-First and second helical gears-
In this example, the first helical gear 51 integrally forms a ring-shaped gear body having a diameter larger than the outer diameter of the flange 32 with the flange 32, and is formed on the peripheral surface of the gear body with respect to the rotating shaft. The gear is cut in the direction of twisting diagonally.
Further, as shown in FIGS. 3 and 4, the second helical gear 52 has a rotating shaft 52b extending outward in the axial direction at the center of the gear body 52a (see FIG. 6), and is a photoconductor. The rotating shaft 52b is held on the holding arm 35 of the housing 34 by a bearing portion 37 formed in advance along with the bearing portion 36 so as to be rotatable and allow the rotating shaft 52b to move in the axial direction. be. On the other hand, an overhanging portion 52d is formed on the surface of the gear body 52a opposite to the rotating shaft 52b so as to project toward the end side of the transfer roll 40.
Then, in this example, the meshing state of the first helical gear 51 and the second helical gear 52 is such that when the first helical gear 51 is rotationally driven in a predetermined predetermined direction, the first helical gear 51 is rotationally driven. When the helical gear 52 of 2 rotates following this, the axial load (thrust load) acting on the second helical gear 52 acts toward the end side of the transfer roll 40. Has been selected. Further, in this example, the rotating shaft 52b is arranged so as to penetrate the bearing portion 37, but the tip portion of the rotating shaft 52b has a flange portion 52c formed in a slit shape, and the rotating shaft 52b is a bearing portion. It works as a stopper when sliding along 37. Further, the overhanging portion 52d is configured as a cylindrical portion having a diameter smaller than the outer diameter of the gear main body 52a with the center of the gear main body 52a as the center.

-Support member-
In the present embodiment, the bearing 44 of the transfer roll 40 is made of, for example, a molded product made of a conductive resin, and has a cylindrical recess that rotatably holds the support shaft 41 of the transfer roll 41.
In this example, the support member 53 is integrally molded with the bearing 44, and is a cylindrical connecting cylinder extending toward the second helical gear 52 side across the partition wall of the cylindrical recess of the bearing 44. Has a body 61. The connecting cylinder 61 is formed by opening the second helical gear 52 side and forming a pair of elongated holes 62 extending in the axial direction of the second helical gear 52 at the opposing portions of the peripheral wall thereof. be.

-Displacement mechanism-
In this embodiment, the displacement mechanism 54, as shown in FIG. 5, and the second helical gear 52 provided separately, the second of the helical with helical gear 52 of the second gear The transfer roll 40 is moved from the retracted position P0 to the contact position P1 via the support member 53 with the movement of the axially movable portion 70a that moves toward the support member 53 side along the rotation axis direction of the 52 and the axially movable portion 70a. It is provided with a contact / disengagement direction movable portion 70b to be moved to, and has a displacement member 70 in which the axial direction movable portion 70a and the contact / separation direction movable portion 70b are integrated with a synthetic resin.
In this example, the axially movable portion 70a of the displacement member 70 has a columnar rod 71 inserted into the connecting cylinder 61 of the support member 53, and is on the second helical gear 52 side of the rod 71. Is formed with a flange portion 72 and a pair of stopper protrusions 73 slidable along the elongated hole 62 of the connecting cylinder 61 on the peripheral wall of the rod 71. The stopper protrusion 73 of this example has a tapered surface 73a that narrows toward the connection cylinder 61 side, and when the rod 71 is inserted into the connection cylinder 61, the stopper protrusion 73 opens the connection cylinder 61. It enters the connecting cylinder 61 while elastically deforming the vicinity, and fits into the elongated hole 62 of the connecting cylinder 61. When the stopper protrusion 73 abuts at the end of the elongated hole 62, the connecting cylinder 61 It is a stopper for the rod 71. Further, the flange portion 72 abuts on the open end of the connecting cylinder 61, and the amount of the rod 71 inserted into the connecting cylinder 61 is restricted.
Further, in the present embodiment, a coil spring 80 for urging the rod 71 in the detaching direction is incorporated in the connecting cylinder 61, and the second helical gear 52 is returned to the initial position as described later. It works when.

Further, the movable portion 70b in the contact / disengagement direction of the displacement member 70 integrally extends a substantially L-shaped push-up arm 75 from a part of the flange portion 72 of the rod 71 toward the end side of the transfer roll 40. A wedge-shaped push-up portion 76 is provided at the tip of the push-up arm 75. The push-up portion 76 of this example has an inclined surface 77 that is inclined toward the tip end so as to approach the contact position P1 side of the transfer roll 40. A butt wall 78 is provided at the tip of the substantially L-shaped holding arm 35 of the photoconductor housing 34 at a portion of the push-up arm 75 facing the push-up portion 76, and the corner portion 78a of the butt wall 78 is provided. (See FIG. 8) has a chamfered structure. Further, the push-up portion 76 of the push-up arm 75 is arranged at a position where its inclined surface 77 abuts against the corner portion 78a of the abutting wall 78, and the push-up portion 76 of the push-up arm 75 abuts against the abutting wall 78. Further, when the push-up arm 75 is pushed further, the push-up portion of the push-up arm 75 rides on the top of the push wall 78 along the inclined surface 77, and the position of the entire push-up arm 75 is displaced toward the contact position P1 side of the transfer roll 40. It has become.

-Power supply mechanism-
In the present embodiment, as shown in FIGS. 4 and 9, a power feeding mechanism 90 for supplying power to the transfer roll 40 is provided. In this power feeding mechanism 90, protrusions 38 and 39 for holding power feeding parts are formed in advance on a part (two places in this example) of the holding arms 35 of the photoconductor housing 34, and one of the protrusions 38 for holding the power feeding parts 38. The base portion 91a of the torsion spring 91 as a power feeding component is hooked on the surface of the bearing 44, and the contact portion portion 91b of the torsion spring 91 is elastically brought into contact with the peripheral surface of the bearing 44 made of conductive resin. Then, the torsion spring 91 is pulled out to a portion facing the outside of the holding arm 35 via the drawing wiring portion 92, and the holding arm is hooked by hooking one end of the drawing wiring portion 92 on another feeding component holding projection 39. It is attached to 35. Therefore, according to the power feeding mechanism of this example, by setting one end of the drawer wiring portion 92 as a feeding point, power is supplied to the transfer roll 40 via the torsion spring 91 and the bearing 44, which are feeding parts. ing.

<Contact / detachment operation by the attachment / detachment mechanism>
Next, the contact / separation operation between the photoconductor 21 and the transfer roll 40 will be described.
First, in the present embodiment, as can be seen from FIG. 2, the transfer roll 40 is configured to be located downward in the vertical direction with respect to the horizontal line passing through the center of the photoconductor 21. Therefore, the transfer roll 40 can easily maintain a non-contact state in which the transfer roll 40 is at the retracted position P0 with respect to the photoconductor 21 due to its own weight, and a urging means for urging the transfer roll 40 toward the retracted position P0 is particularly provided. I don't need it.

6 to 10 are explanatory views showing a state of contact and separation between the photoconductor 21 and the transfer roll 40, FIG. 6 is a plan view, and FIG. 7 is a view of the transfer roll 40 side from the photoconductor 21 side. 8 is a perspective view, FIG. 9 is an explanatory view showing a power feeding mechanism 90 (torsion spring 91, drawer wiring portion 92) used in the present embodiment, and FIG. 10 is a cross section of the transfer housing 42 at the position of the U groove portion 43a. In each case, (a) shows the state at the retracted position P0 where the transfer roll 40 is retracted, and (b) shows the state at the contact position P1 where the transfer rolls 40 are in contact with each other.

-When the photoconductor is stopped-
In these figures, since the photoconductor 21 is stopped at the retracted position P0 where the transfer roll 40 is retracted, the first helical gear 51 is also stopped. Therefore, the driving rotational force of the first helical gear 51 is not transmitted to the second helical gear 52, and the second helical gear 52 remains stopped without rotating. In this state, since the urging force of the coil spring 80 in the connecting cylinder 61 of the support member 53 acts on the second helical gear 52 via the displacement member 70 of the displacement mechanism 54, the second helical gear 52 is second. The helical gear 52 is urged away from the transfer roll 40. Then, the rotating shaft 52b of the second helical gear 52 is rotatably held by the bearing portion 37 of the holding arm 35 of the photoconductor housing 34 and slidably held along the axial direction. When the gear body 52a of the helical gear 52 abuts on the end of the bearing portion 37, the movement of the second helical gear 52 in the direction away from the transfer roll 40 is restricted, so that the second helical gear 52 has a second helical gear 52. The false gear 52 is in a state of stopping at a predetermined stop position (corresponding to the initial position P0).

At this time, the rod 71 of the displacement member 70 protrudes a lot from the connecting cylinder 61 of the support member 53, but the stopper protrusion 73 is caught at the end of the elongated hole 62 of the connecting cylinder 61 on the opening side, and the rod 71 There is no concern that the connecting cylinder 61 will come out, and the return amount of the second helical gear 52 is regulated. Further, since the push-up arm 75 of the displacement member 70 is arranged at a position where it does not contact the abutting wall 78 of the holding arm 35, the displacement member 70 displaces the support member 53 toward the contact position P1 side of the transfer roll 40. The bearing 44 integrated with the support member 53 is held in the same position, and the transfer roll 40 is held in the retracted position P0.

-When the photoconductor is driven and rotated-
Next, when the photoconductor 21 is driven to start rotation, the rotation of the first helical gear 51 causes the second helical gear 52 that meshes with the first helical gear 51 to rotate. The second helical gear 52 receives a thrust force in the direction toward the end side of the transfer roll 40. As a result, the second helical gear 52 moves toward the end side of the transfer roll 40 against the urging force of the coil spring 80 built in the connecting cylinder 61 of the support member 53, and the second helical gear 52 moves toward the end side. The rod 61 of the displacement member 70 in contact with the overhanging portion 52d of the helical gear 52 of 2 is integrally moved toward the end side of the transfer roll 40. Then, the tip of the push-up arm 75 of the displacement member 70 comes to abut against the corner portion 78a of the abutting wall 78, and the push-up arm 75 is provided by the inclined surface 77 of the push-up portion 76 provided at the tip of the push-up arm 75. Gradually moves toward the top side of the abutting wall 78 and rides on the top of the abutting wall 78. In this state, the movement of the push-up arm 75 of the displacement member 70 causes the entire displacement member 70 to move in a direction approaching the peripheral surface of the photoconductor 21, so that the support member to which the rod 71 of the displacement member 70 is connected is connected. The connection cylinder 61 of 53 is lifted in a direction approaching the peripheral surface of the photoconductor 21, and the bearing 44 integrated with the connection cylinder 61 is along the U groove portion 43a of the bearing holding portion 43 of the transfer housing 42. It moves in a direction approaching the peripheral surface of the photoconductor 21. Therefore, the transfer roll 40 approaches the photoconductor 21 side together with the bearing 44, and finally reaches the contact position P1 in contact with the photoconductor 21. Here, in the present embodiment, with respect to the push-up portion 76 of the push-up arm 75 of the displacement member 70, the amount of displacement along the contact / separation direction of the transfer roll 40 is the contact position P1 and the retracted position P0 of the transfer roll 40. It is set to be slightly larger than the distance between them, and at the contact position P1, the transfer roll 40 is placed in a state of being in pressure contact with the photoconductor 21.

Further, since the photoconductor 21 continues to rotate at the contact position P1, the first helical gear 51 and the second helical gear 52 continue to rotate, and the second helical gear 52 has a thrust force. Works continuously. However, since the amount of movement of the rod 71 in the sliding direction is restricted at the position where the flange portion 72 of the rod 71 of the displacement member 70 abuts on the end of the connecting cylinder 61 of the support member 53, the second helical gear The amount of movement of the 52 in the thrust direction is regulated by the movement regulation of the rod 71 of the displacement member 70. Therefore, the second helical gear 52 cannot move further to the transfer roll 40 side. As a result, the axial position of the transfer roll 40 is maintained at the contact position P1.

-When stopped from the photoconductor drive rotation-
Next, when the photoconductor 21 is stopped, the first helical gear 51 is stopped, so that the thrust force generated by the second helical gear 52 is eliminated. Then, the urging force of the coil spring 80 exerts its effect, and tries to move the second helical gear 52 in the direction away from the transfer roll 25 via the rod 71 of the displacement member 70. As a result, the second helical gear 52 gradually moves away from the transfer roll 40 while rotating along the teeth of the stopped first helical gear 51. Similarly, since the entire displacement member 70 also moves together, the push-up arm 75 of the displacement member 70 moves in the direction away from the abutting wall 78. As a result, when the push-up portion 76 of the push-up arm 75 comes off from the abutting wall 78, the push-up operation of the support member 53 by the push-up arm 75 is released. Both the bearing 44 and the bearing 44 are retracted to the retracted position P0 away from the peripheral surface of the photoconductor 21. After that, the transfer roll 40 repeats contact and separation between the retracted position P0 and the contact position P1 as the photoconductor 21 rotates and stops.

As described above, in the present embodiment, when the transfer roll 40 is brought into contact with and detached from the photoconductor 21, the contact and detachment mechanism 50 utilizing the rotational force for driving the photoconductor 21 is used, and the photoconductor 21 rotates. Since the transfer roll 40 is displaced to the contact position P1 in contact with the photoconductor 21 and the transfer roll 40 is displaced to the retracted position P0 retracted from the photoconductor 21 when the photoconductor 21 is stopped, another drive source is used. Without this, an unnecessary contact state between the photoconductor 21 and the transfer roll 40 for a long time outside the image formation period can be avoided.
In the present embodiment, the rotation of the photoconductor 21 is continuously performed, for example, during the time when it is determined that the image forming apparatus 10 is to form an image, and when it is determined that the image forming is completed. Needless to say, the photoconductor 21 is stopped so that the rotation of the photoconductor 21 does not switch in a short time. Further, it goes without saying that the image formation is performed after the photoconductor 21 starts rotating and a predetermined time elapses, that is, after the transfer roll 40 is displaced to the contact position P1.

Further, in the present embodiment, as shown in FIG. 8, the rotation center axes of the second helical gear 52 and the transfer roll 40 at the retracted position P0 are arranged on substantially the same line. Therefore, if the center positions of the connecting cylinder 61 of the support member 53 and the rod 71 of the displacement member 70 are set in accordance with the rotation center axis of the transfer roll 40, the second helical gear 52 and the displacement member can be set. When the rod 71 of the 70 is brought into contact with the rod 71, the center positions of the two can be substantially aligned to secure a wide contact area between the two, and the thrust force of the second helical gear 52 can be easily transmitted to the displacement member 70. .. Further, in this example, the overhanging portion 52d of the second helical gear 52 and the flange portion 72 formed at the end of the rod 71 of the displacement member 70 form a contact portion between the two, for example. Even if the displacement member 70 is displaced in the contacting / separating direction of the transfer roll 40, the flange portion of the displacement member 70 facing the overhanging portion 52d of the second helical gear 52 so that the contact area between the two can be maintained. It is preferable to select the area of 72 wider than the facing area of the overhanging portion 52d.
Further, the urging force of the coil spring 80 is also easily transmitted to the second helical gear 52 side. Therefore, in this example, it becomes easy to obtain a compact and more stable contact / detachment mechanism 50.

In the present embodiment, the first helical gear 51 and the second helical gear 52 are provided on both ends of the photoconductor 21 and the transfer roll 40, respectively, but they are provided on one side. In that case, the moving direction of the second helical gear 52 and the moving direction of the displacement member 70 at the retracted position P0 are slightly deviated from the straight line, but the thrust force is transmitted between the two. Since this is done without any trouble, the transfer roll 40 is displaced without any trouble between the retracted position P0 and the contact position P1. Further, at this time, the posture angle of the push-up arm 75 of the displacement member 70 may be slightly changed.

In the present embodiment, the drum-shaped photoconductor 21 is used as the rotating body, but a belt member may be used as the rotating body, for example, a contact / separation mechanism between the photoconductor belt and the transfer roll 40. The above-mentioned contact / detachment mechanism may be used for the above.
Further, in the present embodiment, the transfer roll 40 can be stabilized at the retracted position P0 by its own weight, but for example, an urging means for urging the transfer roll 40 to the retracted position P0 side is further provided. It goes without saying that it is okay to do so.
Further, in the present embodiment, the mode of using the contact / detachment mechanism 50 between the photoconductor 21 and the transfer roll 40 is shown. For example, a mode of using a charging roll as a charging device or a cleaning roll as a cleaning device is used. In the case where these are arranged downward in the vertical direction with respect to the horizontal line passing through the center of the photoconductor 21, the above-mentioned contact / detachment mechanism may be used.

◎ Embodiment 2
11 (a) and 11 (b) are explanatory views showing a main part of the transfer roll contact / detachment mechanism in the second embodiment, and FIG. 11 (a) shows a state when the transfer roll is arranged at the retracted position P0. (B) shows the state when the transfer roll is arranged at the contact position P1 respectively.
The contact / detachment mechanism 50 of the transfer roll 40 used in the present embodiment has substantially the same configuration as that of the first embodiment (see FIG. 5), but includes a displacement mechanism 54 different from that of the first embodiment. In particular, in the present embodiment, although the position of the transfer roll 40 is arranged downward in the vertical direction with respect to the horizontal line passing through the center of the photoconductor 21, when the transfer roll 40 is retracted from the contact position P1 to the retracted position P0. In addition, it is applied when the transfer roll 40 is difficult to return to the retracted position P0 only by its own weight. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted here.

In the present embodiment, the attachment / detachment mechanism 50 of the transfer roll 40 has substantially the same elements as those of the first embodiment (first spring (not shown)) as shown in FIGS. 11 (a) and 11 (b) and 12. It includes a helical gear, a second helical gear 52, a support member 53 (connecting cylinder 61, elongated hole 62), and a coil spring 80 for returning the second helical gear 52 to its initial position.
As shown in FIGS. 11 to 15, the displacement mechanism 54 has a displacement member 70 (rod 71, collar portion 72, stopper protrusion 73, push-up arm 75, push-up portion 76, inclined surface 77) substantially similar to those in the first embodiment. ) And the abutting wall 78 related to the pushing operation of the pushing arm 75. In addition to this, the transfer roll 40 located at the contact position P1 when the photoconductor 21 is stopped is moved to the retracting position P0. A return mechanism 100 is provided so that the support member 53 is returned in a direction away from the peripheral surface of the photoconductor 21 so as to retract.

In the present embodiment, the return mechanism 100 is provided with a push-down arm 101 projecting toward the end of the transfer roll 40 in a part of the holding arm 35 of the photoconductor housing 34, and is provided at the tip of the push-down arm 101. A wedge-shaped pressing portion 102 is provided. The pressing portion 102 of this example has an inclined surface 103 that is inclined so as to approach the contact position P1 side of the transfer roll 40 toward selection.
Then, in this example, the inclined surface 103 of the pressing portion 102 of the pressing arm 101 is an edge located closer to the lower half of the upper half of the flange portion 72 formed at the end of the rod 71 of the displacement member 70. A notch 110 is formed in the flange portion 72 facing the inclined surface 103 of the pressing portion 102, and the notch 110 has substantially the same inclination as the inclined surface 103 of the pressing portion 102. An inclined surface 111 is provided.
Here, since the bearing portion 37 and the push-down arm 101 of the second helical gear 52 are both provided on the holding arm 35 of the photoconductor housing 34, the push-down arm 101 is the second helical gear. It needs to be arranged at a position that does not interfere with the gear 52. Therefore, in this example, as shown in FIG. 14, the rotation center axis of the second helical gear 52 is not arranged coaxially with the rotation center axis of the transfer roll 40, but is located on the rotation center axis of the transfer roll 40. On the other hand, they are arranged non-coaxially, which is biased when viewed from the photoconductor 21 side. The push-down arm 101 is provided on the side opposite to the side with the rotation center axis of the second helical gear 52 with the rotation center axis of the transfer roll 40 interposed therebetween when viewed from the photoconductor 21 side. .. In this example, the flange portion 72 of the displacement member 70 is provided with a dummy notch portion 115 in addition to the notch portion 110, and this introduces the contact / detachment mechanism 50 on both sides of the transfer roll 40 in the axial direction. At this time, notches 110 and 115 are provided at two locations so that the same component can be used as the displacement member 70, which is an element of the contact / detachment mechanism 50.

Next, the behavior of the transfer roll contact / detachment mechanism in the present embodiment will be described.
-When the photoconductor is driven and rotated-
In the present embodiment, when the photoconductor 21 is driven and rotated, the first helical gear 51 and the second helical gear 52 rotate as shown in FIGS. 13 to 15, and the second helical gear 52 rotates. A thrust force is generated in the helical gear 52, and the second helical gear 52 and the displacement member 70 are integrally moved to the transfer roll 40 side. As a result, the push-up arm 75 of the displacement member 70 abuts against the abutting wall 78 of the holding arm 35 to perform the push-up action of the displacement member 7, and the displacement member from the push portion 102 of the push-down arm 101 of the return mechanism 100. The notch 110 formed in the flange portion 72 of the 70 is separated, and the return action by the return mechanism 100 is released.
During this time, since the return mechanism 100 is in the released state, the push-up arm 75 rides on the top of the abutting wall 78, and the entire position member 70 gradually approaches the peripheral surface of the photoconductor 21. The transfer roll 40 comes into contact with the peripheral surface of the photoconductor 21 and reaches the contact position P1.

-When the photoconductor is driven from rotation to stop-
On the other hand, when the photoconductor 21 is stopped, the displacement member 70 and the second helical gear 52 gradually move away from the transfer roll 40 due to the urging force of the coil spring 80. As a result, when the push-up arm 75 of the displacement member 70 comes off from the top of the abutting wall 78 of the holding arm 35, the transfer roll 40 is separated from the peripheral surface of the photoconductor 21. At this time, as the displacement member 70 moves, the flange portion 72 of the displacement member 70 also moves away from the end portion of the transfer roll 40. Then, the notch 110 formed in the flange portion 72 of the displacement member 70 abuts on the push portion 102 of the push-down arm 101 of the return mechanism 100, and the displacement member 70 moves in a direction away from the end portion of the transfer roll 40. Then, since the inclined surface 111 of the cutout portion 110 is pushed down along the inclined surface 103 of the pressing portion 102, the displacement member 70 moves in a direction away from the peripheral surface of the photoconductor 21. Then, when the second helical gear 52 returns to the initial position, the movement of the displacement member 70 also stops, and the return mechanism 100 restrains the displacement member 70 to a predetermined position away from the peripheral surface of the photoconductor 21. In this state, the bearing 44 supported by the displacement member 70 via the support member 53 also follows the movement of the displacement member 70 and separates from the peripheral surface of the photoconductor 21, resulting in the transfer roll 40. Will be kept at the retracted position P0. As described above, even if it is difficult to reach the retracted position P0 only by the weight action of the transfer roll 40 when the photoconductor 21 is stopped, in the present embodiment, the transfer roll 40 is forcibly retracted by the return mechanism 100. It is possible to return to the position P0.

Here, the timing at which the push-up arm 75 of the displacement member 70 comes off from the abutting wall 78 of the holding arm 35 and the timing at which the pressing portion 102 of the pushing-down arm 101 of the return mechanism 100 abuts at the notch 110 of the displacement member 70 are the same. The timing may be the same, or the timing may be different.
Then, in the present embodiment, as shown in FIGS. 14A and 14B, when viewed from the photoconductor 21 side, the rotation center of the second helical gear 52 with respect to the rotation center axis of the transfer roll 40. The axis is in a biased manner. Therefore, regarding the contact portion structure between the second helical gear 52 and the displacement member 70, the displacement amount in the contact / separation direction of the transfer roll 40 is taken into consideration, and the overhanging portion 52d of the second helical gear 52 It is preferable to select the displacement member 70 so as to secure a contact area between the displacement member 70 and the flange portion 72.

Further, in such a configuration, in the retracting position P0, the pushing portion 102 of the pushing arm 100 abuts on the notch 110 of the displacement member 70, and the returning mechanism 100 is in a state of restraining the position of the displacement member 70. Therefore, if the displacement member 70 is restrained and held by using the return mechanism 100, the transfer roll 40 is restrained and held at the retracted position P0 even if a mechanical impact is applied during transportation of the image forming apparatus 10, for example. Therefore, the transfer roll 40 does not flutter.

◎ Embodiment 3
FIG. 16 is an explanatory view showing an outline of the image forming apparatus according to the third embodiment, and FIGS. 17 (a) and 17 (b) show the contact / separation mechanism between the photoconductor 21 and the transfer roll 25 according to the present embodiment. In the explanatory view, (a) shows the state at the retracted position P0 where the two are separated from each other, and (b) shows the state at the contact position P1 where the two are in contact with each other. In these figures, the contact / detachment mechanism of the present embodiment is configured in substantially the same manner as that of the second embodiment, but unlike the second embodiment, the transfer roll 40 is directed to a horizontal line passing through the center of the photoconductor 21. It is located upward in the vertical direction. The same components as those in the second embodiment are designated by the same reference numerals, and the description thereof will be omitted here.

In the present embodiment, as shown in FIG. 16, the center position of the transfer roll 40 is arranged above the center position of the photoconductor 21. Therefore, for example, as in the first embodiment (see FIG. 6), in a mode in which the second helical gear 52 and the displacement member 70 of the displacement mechanism 54 are simply in surface contact with each other, the weight of the transfer roll 40 causes the transfer roll 40 to make surface contact. What is in the retracted position P0 may reach the contact position P1. As such a measure, for example, the transfer roll 40 may be provided with a separate urging means so as to be maintained at the retracted position P0 away from the photoconductor 21, but such urging means may be used for transfer. Since an urging force that opposes the gravity of the roll 40 is required, it is not easy to displace the transfer roll 40 between the retracted position P0 and the contact position P1 in such a mode having the urging force.

In the present embodiment, a configuration is adopted in which the transfer roll 40 can be stably held at the retracted position P0 without providing an urging means for urging the transfer roll 40 to be held at the retracted position P0. It was done. Therefore, the present embodiment is realized by the same configuration as that of the second embodiment, but the relationship between the push-up arm 75 of the displacement member 70 and the abutting wall 78 and the notch of the displacement member 70 as the return mechanism 100. The relationship between the portion 110 and the pressing portion 102 of the pressing arm 101 is taken into consideration.

That is, in the present embodiment, the transfer roll 40 at the retracted position P0 is kept in a state where the pressing portion 102 of the pressing arm 101 hits the notch 110 of the displacement member 70 and is separated from the photoconductor 21. Therefore, when the photoconductor 21 rotates, the second helical gear 52 moves to the transfer roll 40 side due to the thrust force generated in the second helical gear 52 that meshes with the first helical gear 51. start. Then, as the displacement member 70 moves, the notch 100 of the displacement member 70 comes out of the push portion 102 of the push-down arm 101, while the push-up portion 76 of the push-up arm 75 of the displacement member 70 hits the abutting single wall 78. Move in the direction of collision.

Here, if the push-up arm 75 of the displacement member 70 hits the abutting wall 78 first and tries to enter between the abutting wall 78 and the bearing 44, the pushing-down arm 101 of the return mechanism 100 is pushed. If the notch 110 of the displacement member 70 is not removed from the portion 102, an extra load is applied to the displacement member 70 and the like, which may cause damage to the displacement member 70, for example. Therefore, under the condition that the notch 110 of the displacement member 70 is removed from the pressing portion 102 of the pushing arm 101, the pushing upper portion 76 of the pushing arm 75 hits the abutting wall 78, and the pushing arm 75 hits the abutting wall 78. You just have to ride on. In particular, by matching the timings of both of these, it is possible to bring the transfer roll 40 into contact with the photoconductor 21 in a relaxing operation. As a result, the transfer roll 40 reaches the contact position P1.

Next, when the photoconductor 21 stops, the second helical gear 52 and the displacement member 70 move in the direction away from the transfer roll 40 due to the urging force of the coil spring 80, and the push-up arm 75 of the displacement member 70 thrusts. When the notch 110 of the displacement member 70 abuts on the push portion 102 of the push-down arm 101 of the return mechanism 100 after being disengaged from the abutting wall 78, the notch 110 of the displacement member 70 is pushed down along the inclined surface 103 of the push portion 102. , The displacement member 70 is displaced in the direction away from the photoconductor 21. As a result, the transfer roll 40 reaches the retracted position P0 away from the photoconductor 21.

In the present embodiment, when the photoconductor 21 is driven and rotated, the timing at which the push-up arm 75 of the displacement member 70 rides on the abutting wall 78 and the notch portion of the displacement member 70 from the push portion 102 of the push-down arm 101 of the return mechanism 100 The timing at which 110 is pulled out is adjusted, but the timing at which the notch 110 of the displacement member 70 is pulled out from the push portion 102 of the push-down arm 101 is earlier than the timing at which the push-up arm 75 of the displacement member 70 rides on the abutting wall 78. If this is done, damage to the displacement member 70 is effectively avoided. However, in this case, it goes without saying that the transfer roll 40 comes into contact with the photoconductor 21 with a certain impact force when reaching the contact position P1 from the retracted position P0.

Although the transfer roll 40 is brought into contact with and detached from the photoconductor 21 in the present embodiment as well, the present invention is not limited to this, and instead of the transfer roll 40, a charging roll as a charging device and a cleaning device can be used. It may be used for a cleaning roll.

1 ... Rotating body, 2 ... Movable member, 3 ... First drive transmission member, 4 ... Second drive transmission member, 5 ... Support member, 6 ... Displacement mechanism, 6a ... Pushing part, 7 ... Axial movable part, 8 ... Moving part in the contact / separation direction, 9 ... Displacement member, P0 ... Retracting position, P1 ... Contact position

Claims (11)

A contact / detachment mechanism that attaches / detaches a movable member to / from the peripheral surface of a rotating body that can be driven and rotated.
A first drive transmission member composed of helical gears provided on the end side in the width direction intersecting the rotation direction of the rotating body, to which the rotational force of the rotating body is transmitted and rotationally driven around the center of rotation. ,
It is provided so as to mesh with the first drive transmission member, is held at a predetermined initial position when the rotating body does not drive and rotate, and rotates when the rotating body drives and rotates. A second drive transmission member composed of a helical gear that transmits force to follow and rotate around the center of rotation and is moved toward the rotating body along the direction of the center of rotation.
A support member that removably supports the movable member between a contact position where the movable member comes into contact with the peripheral surface of the rotating body and a retracted position where the movable member retracts.
When the second drive transmission member is provided between the second drive transmission member and the support member and is moved from the initial position along the rotation center axis direction, the rotation center axis direction. With a displacement mechanism that displaces the support member toward the support member along the line, contacts the support member, presses the support member in a direction approaching the peripheral surface of the rotating body, and displaces the movable member to the contact position. ,
A contact / detachment mechanism characterized by being provided with. In the contact / detachment mechanism according to claim 1,
The first drive transmission member, the second drive transmission member, the support member, and the displacement mechanism are provided on both ends in the width direction intersecting the rotation direction of the rotating body, respectively. Contact / detachment mechanism. In the contact / detachment mechanism according to claim 1 or 2.
The second drive transmission member includes an urging member that is urged to be held at the initial position when the rotating body does not drive and rotate. In the contact / detachment mechanism according to claim 3,
A contact / detachment mechanism, wherein the urging member is housed in the support member. In the contact / detachment mechanism according to claim 1 or 2.
The displacement mechanism is provided separately from or integrally with the second drive transmission member, and together with the second drive transmission member, the support member side along the rotation center axis direction of the second drive transmission member. It is provided with an axial movable portion that moves to, and a contact / detachable movable portion that moves the movable member from the retracted position to the contact position via the support member as the axial movable portion moves.
A contact / detachment mechanism characterized in that at least one of the axially movable portion or the contact / detachment direction movable portion has a pressing portion that presses the support member in a direction approaching the peripheral surface of the rotating body. In the contact / detachment mechanism according to claim 5,
The displacement mechanism has one displacement member in which the axial movable portion and the contact / detachable movable portion are integrated, and guides the axial movable portion with respect to the support member while sliding the axial movable portion. A contact / detachment mechanism characterized in that the support member is pressed toward a contact position of the movable member by abutting the pressing portion provided on the movable portion in the contact / separation direction with a corner portion facing the pressing portion. In the contact / detachment mechanism according to claim 5,
The displacement mechanism comprises the axial movable portion and the contact / detachment direction movable portion as separate bodies, and has the pressing portion at a portion where the axial movable portion and the contact / separation direction movable portion are engaged with each other. Characteristic contact / detachment mechanism. In the contact / detachment mechanism according to claim 1 or 2.
The displacement mechanism is a contact / detachment mechanism having a return mechanism for returning the support member to the retracted position side of the movable member when the second drive transmission member returns to the initial position. In the contact / detachment mechanism according to claim 8,
The return mechanism of the displacement mechanism is arranged in parallel at a position substantially parallel to the rotation center axis of the second drive transmission member.
When said second drive transmission member is returned to the initial position, the rotation center axis of said viewed from the rotating body side second drive transmission member in a direction along the width direction of the rotating body of said movable member A contact / detachment mechanism characterized in that it is arranged unevenly with respect to the central axis. The attachment / detachment mechanism according to any one of claims 1 to 9 , wherein the movable member is a rotatable rotating member.
A contact / detachment mechanism characterized in that the support member is provided on a bearing that rotatably holds the movable member as a rotating member. A latent image holder that holds an electrostatic latent image,
A charger that charges the latent image holder to form an electrostatic latent image,
A developer that develops the electrostatic latent image on the latent image holder with a developer, and
A transfer device that transfers an image developed by the developer and formed on the latent image holder to a recording material, and a transfer device.
A cleaning device that cleans the latent image holder after being transferred by the transfer device,
Including
The invention according to any one of claims 1 to 10 , wherein the latent image holder is a rotating body, and the charging device, the transfer device, and at least one of the cleaning devices are movable members. An image forming apparatus characterized by using the contact / detachment mechanism of the above.

Images