JP7358161B2 - Image forming device - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer.

2. Description of the Related Art As an electrophotographic image forming apparatus, a configuration of an image forming apparatus is known, which includes a transfer unit having a belt such as a conveyor belt or an intermediate transfer belt, and transfers a toner image from an image forming section to the belt. The image forming section has a drum-shaped photoreceptor (hereinafter referred to as a photoreceptor drum), and the toner image carried on the photoreceptor drum is transferred to a transfer material such as paper that is conveyed by a transfer material conveyance belt. Alternatively, the image is transferred once to an intermediate transfer belt and then transferred to a transfer material. Thereafter, the toner image transferred to the transfer material is fixed to the transfer material by a fixing means. Here, the toner image is transferred from the photosensitive drum to the transfer material or the intermediate transfer belt by a transfer member disposed at a position opposite to the photosensitive drum via the transfer material conveying belt or the intermediate transfer belt, and by a transfer unit. This is carried out by applying a voltage to a transfer member provided on the transfer member.

Patent Document 1 discloses that a transfer member can be brought into contact with or separated from a photosensitive drum via a belt, and when a transfer unit is removed from an image forming apparatus, a user manually moves a lever to bring the transfer member into contact with or away from a photosensitive drum. Disclosed is a configuration for spacing the drum from the drum. According to this configuration, when the transfer unit is removed, the transfer member is held at a position separated from the photosensitive drum, so that wear and damage of the transfer unit can be suppressed.

Japanese Patent Application Publication No. 2009-109584

However, in the configuration of Patent Document 1, when the transfer unit is taken out from the image forming apparatus, the user needs to manually move the lever, which may make the operations performed by the user complicated.

Therefore, an object of the present invention is to remove the transfer unit from the image forming apparatus with a simpler operation while suppressing wear and damage of the transfer unit.

The present invention includes a photoconductor carrying a toner image, a movable belt, and a transfer section where the belt and the photoconductor come into contact, and the toner image carried on the photoconductor is transferred in the transfer section. a transfer unit having a transfer member that transfers data toward the belt ; a biasing member that biases the transfer member toward the photoreceptor ; and an opening/closing door provided in an opening for removing the transfer unit. , in which the transfer unit is removable from the opening in the first direction , when the opening/closing door is closed , the transfer unit is removed in the first direction. The transfer unit is removed from the image forming apparatus with the transfer member being biased by the abutting member disposed between the door and the opening/closing door and the transfer member being biased to form a transfer portion. A regulating means for regulating the movement of the transfer member against the biasing force of the biasing member so that the belt and the abutment member do not come into contact when the belt is removed; , a support member that supports an end of the transfer member and is biased by a bias member; and a support portion that is capable of contacting the support member and is provided on the main body of the image forming apparatus, and the regulating means is , a support member, a support part, and a biasing member, and after the support member and the support part come into contact with each other, the support member moves against the biasing force of the biasing member while supporting the transfer member. It is characterized in that movement of the transfer member is regulated .

According to the present invention, it is possible to remove the transfer unit from the image forming apparatus with a simpler operation while suppressing wear and damage of the transfer unit.

1 is a schematic cross-sectional view illustrating the configuration of an image forming apparatus of Example 1. FIG. FIG. 3 is a schematic diagram illustrating the support structure of the transfer unit of Example 1. FIG. 3 is a schematic cross-sectional view illustrating a transfer unit in a monochrome contact state in Example 1. FIG. FIG. 2 is a schematic cross-sectional view illustrating a state in which the opening/closing door is opened in Example 1. FIG. 3 is a schematic cross-sectional view illustrating removal of the transfer unit in a monochrome contact state in Example 1. FIG. FIG. 3 is a schematic diagram illustrating a regulating means of Example 1. FIG. FIG. 2 is a schematic cross-sectional view illustrating the configuration of an image forming apparatus according to a second embodiment. FIG. 7 is a schematic diagram illustrating a regulating means in Example 2. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following examples should be changed as appropriate depending on the configuration and various conditions of the device to which the present invention is applied. Therefore, unless there is a specific description, it is not intended to limit the scope of the present invention.

(Example 1)
[Configuration of image forming apparatus]
FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 of this embodiment. As shown in FIG. 1, the image forming apparatus 1 of this embodiment is an intermediate transfer type color image forming apparatus using an electrophotographic method, and has a plurality of image forming means: first, second, and third image forming means. , fourth image forming sections Sa, Sb, Sc, and Sd. The first, second, third, and fourth image forming sections Sa, Sb, Sc, and Sd form images of yellow (Y), magenta (M), cyan (C), and black (Bk), respectively. It is for the purpose of These four image forming sections Sa, Sb, Sc, and Sd are arranged in a row at regular intervals, and furthermore, in this embodiment, each of the image forming sections Sa, Sb, Sc, and Sd are , are arranged below the intermediate transfer belt 9 in the direction of gravity. In this embodiment, the configurations of the first to fourth image forming sections Sa, Sb, Sc, and Sd are substantially the same except that the colors of the toners used are different. Therefore, unless there is a particular distinction, the suffixes a, b, c, and d given to the reference numerals to indicate which color the element is provided for will be omitted, and a general description will be given.

Each image forming apparatus S is provided with a drum-shaped electrophotographic photosensitive member 3 (hereinafter referred to as photosensitive drum 3) which is rotatable and serves as an image carrier on which a toner image is formed. A charging roller 21 as a charging member that charges the photosensitive drum 3, a developing means 22, and a cleaning means 24 are installed around the photosensitive drum 3. In addition, an exposure section is provided on the downstream side of the charging roller 21 and upstream of the developing means 22 with respect to the rotational direction of the photosensitive drum 3, and is irradiated with laser light from the exposure means 7 (laser scanner). It is being

The developing means 22 includes a developing roller 23 as a developing member and toner as a developer. The developing roller 23 is rotatable by receiving a driving force from a driving source (not shown). The cleaning means 24 has a cleaning blade 25 as a cleaning member that comes into contact with the photosensitive drum 3, and stores toner collected by the cleaning blade 25.

Next, the overall configuration of the image forming apparatus 1 will be described. As shown in FIG. 1, an intermediate transfer belt 9, which is an endless intermediate transfer body, is arranged opposite to the photosensitive drum 3 of the image forming section S. The intermediate transfer belt 9 is stretched around a plurality of tension members, and more specifically, it is stretched around three tension rollers: a drive roller 62 , a driven roller 61 , and a tension roller 63 . Further, the intermediate transfer belt 9 is movable in the direction of arrow AA in the drawing by rotation of a drive roller 62 that rotates in response to a driving force from a drive source (not shown).

A primary transfer roller 4 serving as a primary transfer member (transfer member) is arranged at a position facing the photosensitive drum 3 via the intermediate transfer belt 9 . The primary transfer roller 4 is urged against the photosensitive drum 3 with a predetermined pressure via the intermediate transfer belt 9, and is located at a primary transfer portion (transfer portion) where the intermediate transfer belt 9 and the photosensitive drum 3 are in contact with each other. It forms N1. Further, a primary transfer power source 40 is connected to the primary transfer roller 4, and the primary transfer power source 40 can apply a voltage of positive polarity or negative polarity to the primary transfer roller 4.

On the outer peripheral surface side of the intermediate transfer belt 9, a secondary transfer roller 10 as a secondary transfer member held by a secondary transfer means 14 is arranged at a position facing the drive roller 62. The secondary transfer roller 10 is urged with a predetermined pressure against the drive roller 62 via the intermediate transfer belt 9, and is located at a secondary transfer portion (2) where the intermediate transfer belt 9 and the secondary transfer roller 10 are in contact with each other. A next transfer nip) N2 is formed. A secondary transfer power source 41 is connected to the secondary transfer roller 10 , and the secondary transfer power source 41 can apply a voltage of positive polarity or negative polarity to the secondary transfer roller 10 .

With respect to the moving direction of the intermediate transfer belt 9, toner remaining on the intermediate transfer belt 9 after the secondary transfer (hereinafter referred to as residual toner) is located upstream of each photosensitive drum 3 and downstream of the secondary transfer portion N2. A cleaning means 20 is provided for collecting the water. The cleaning means 20 has a cleaning blade 20a that comes into contact with the intermediate transfer belt 9.

Upstream of the secondary transfer section N2 with respect to the conveyance direction of the transfer material P, there are a paper feed cassette 2 for storing the transfer material P, a feed roller 30 for feeding the transfer material P, and a feed roller 30 for feeding the transfer material P. Conveyance rollers 31 and 32 for conveying to the secondary transfer portion N2 and a pre-transfer guide 15 are provided. Here, the pre-transfer guide 15 is a guide member that guides the transfer material P transported by the transport rollers 31 and 32 to the secondary transfer portion N2. Further, with respect to the conveyance direction of the transfer material P, on the downstream side of the secondary transfer portion N2, there are a fixing unit 33 equipped with a heat source, and a paper discharge roller 34 for discharging the transfer material P from the image forming apparatus 1. A paper discharge tray 35 for stacking the discharged transfer material P is provided.

Further, the image forming apparatus 1 has a door 13 as an opening/closing door, and when the transfer material P stays inside the apparatus main body, the door 13 can be opened to release an opening provided in the apparatus main body. It is possible to remove the retained transfer material P. For example, if the transfer material P is held in the secondary transfer section N2, the user opens the door 13 to release the opening, and then rotates the secondary transfer means 14 to move the transfer material P to the secondary transfer section N2. By releasing the transfer material P, the accumulated transfer material P can be removed from the inside of the image forming apparatus 1. Here, the door 13 can open and close the opening by rotating around the rotation axis 13a, and the secondary transfer means 14 can open and close the opening by rotating around the rotation axis 14a. It is possible to release the secondary transfer portion N2.

[Image forming operation]
When an operation start command and an image signal from a host device (not shown) are transmitted to the controller 36 as a control means, the image forming apparatus 1 starts an image forming operation by the controller 36 controlling various means. When the image forming operation is started, each of the photosensitive drums 3, intermediate transfer belt 9, and developing roller 23 starts rotating at a predetermined rotational speed in response to a driving force from a driving source (not shown). The surface of the rotating photosensitive drum 3 is substantially uniformly charged to a predetermined polarity (negative polarity in this embodiment) by a charging roller 21 . At this time, a predetermined charging voltage is applied to the charging roller 21 from a charging power source (not shown). Thereafter, the photosensitive drum 3 is exposed to light by the exposure means 7 based on the image information corresponding to each image forming section S, thereby forming an electrostatic latent image on the surface of the photosensitive drum 3 according to the image information. .

The developing roller 23 carries toner charged to the normal charging polarity (negative polarity in this embodiment), and is applied with a predetermined developing voltage from a developing power source (not shown). As a result, the latent image formed on the photosensitive drum 3 is made visible by the negative polarity toner at the opposing portion (developing section) between the photosensitive drum 3 and the developing roller 23, and a toner image is formed on the photosensitive drum 3.

Next, the toner image formed on the photosensitive drum 3 is rotated in the primary transfer portion N1 by a current flowing from the primary transfer roller 4 to the photosensitive drum 3 (hereinafter referred to as primary transfer current). The image is transferred to the intermediate transfer belt 9 (primary transfer). At this time, a voltage having a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the primary transfer roller 4 from the primary transfer power source 40. That is, in the configuration of this embodiment, constant current control is performed to control the output of the primary transfer power source 40 so that a predetermined primary transfer current flows from the primary transfer roller 4 toward the photosensitive drum 3. The toner image is primarily transferred onto the intermediate transfer belt 9.

When forming a full-color image, an electrostatic latent image is formed on each photosensitive drum 3 in each image forming section S, and this is developed into a toner image of each color. The toner images of each color formed on each photosensitive drum 3 of each image forming section S are sequentially transferred to the intermediate transfer belt 9 at each primary transfer section N1a, N1b, N1c, and N1d so as to be superimposed, and the intermediate transfer Four color toner images are formed on the belt 9.

Further, the transfer material P loaded in the paper feed cassette 2 serving as a storage section is fed to the conveyance roller 31 by the feed roller 30, and then conveyed to the secondary transfer section N2 by the conveyance roller 32. The four-color multiple toner image carried on the intermediate transfer belt 9 is transferred at the secondary transfer portion N2 by a current flowing from the secondary transfer roller 10 to the intermediate transfer belt 9 (hereinafter referred to as secondary transfer current). , is transferred (secondary transfer) onto the transferred transfer material P. At this time, a secondary transfer voltage having a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the secondary transfer roller 10 from the secondary transfer power source 41. That is, in the configuration of this embodiment, the intermediate transfer belt is controlled by constant current control that controls the output of the secondary transfer power source 41 so that a predetermined secondary transfer current flows from the secondary transfer roller 10 toward the intermediate transfer belt 9. The toner image is secondarily transferred from 9 to the transfer material P.

Thereafter, the transfer material P onto which the toner image has been transferred is conveyed to the fixing means 33, and after the toner image is fixed on the surface of the transfer material P, it is discharged to the outside of the main body of the image forming apparatus 1. will be loaded on.

Note that the toner remaining on the photosensitive drum 3 after the primary transfer is removed from the surface of the photosensitive drum 3 by the cleaning blade 25 . Further, the transfer residual toner remaining on the intermediate transfer belt 9 after passing through the secondary transfer portion N2 is removed from the surface of the intermediate transfer belt 9 by the cleaning blade 20a.

[Configuration of transfer unit 5]
First, in this embodiment, the primary transfer rollers 4a to 4d change their positions relative to the photosensitive drums 3a to 3d by a drive mechanism (not shown), so that a full color contact state and a monochrome contact state are achieved. It is possible to create three states of total separation. Here, the full color contact state (first state) means that the primary transfer rollers 4a to 4d are brought into contact with the photosensitive drums 3a to 3d via the intermediate transfer belt 9. This is the state shown in FIG. 1 in which the photosensitive drums 3a to 3d are in contact with each other. Further, the monochrome contact state (second state) means that only the primary transfer roller 4d is brought into contact with the photosensitive drum 3d via the intermediate transfer belt 9, and the primary transfer rollers 4a to 4c are in contact with the photosensitive drums 3a to 3c. It is in a state where it is separated from the The fully separated state (third state) is a state in which all the primary transfer rollers 4a to 4d are separated from the photosensitive drums 3a to 3d.

When performing full-color image formation, the controller 36 controls a drive mechanism (not shown) to bring the primary transfer rollers 4a to 4d into a full-color contact state. Thereby, the electrostatic latent images formed on each of the photosensitive drums 3a to 3d can be transferred all at once to the intermediate transfer belt 9, thereby forming a full-color image. Further, when forming a monochrome image, the controller 36 controls a drive mechanism (not shown) to bring the primary transfer rollers 4a to 4d into a monochrome contact state. As a result, a black electrostatic latent image formed on the photosensitive drum 3d can be transferred to the intermediate transfer belt 9 to form a monochrome image, and wear and tear on the photosensitive drums 3a to 3c not used for image formation can be reduced. Can be suppressed.

In this embodiment, the primary transfer rollers 4a to 4d are in a monochrome contact state during standby when no image forming operation is performed. Thereby, when the image forming operation is restarted, for example, when forming a monochrome image, it is not necessary to separately move the primary transfer rollers 4a to 4d, so that the image forming operation can be restarted more quickly. Furthermore, even when forming a full-color image, it is possible to shift to the full-color contact state by intervening only one action of contacting the primary transfer rollers 4a to 4c, and the image forming operation can be resumed more quickly. can.

<Removal of transfer unit 5>
FIG. 2 is a schematic perspective view illustrating the support structure of the transfer unit 5 relative to the main body of the image forming apparatus 1 in this embodiment, and the intermediate transfer belt 9 is not shown in FIG. 2. As shown in FIG. 2, the transfer unit 5 has a belt frame 12 that constitutes a frame of the transfer unit 5. As shown in FIG. The belt frame 12 is slidably supported by a guide rail 11 (guiding portion) fixed to the main body of the image forming apparatus 1, and thereby the transfer unit 5 is supported by the main body of the apparatus. Note that a pair of guide rails 11 are provided at both ends in the width direction of the intermediate transfer belt 9 (direction perpendicular to the moving direction of the intermediate transfer belt 9), which is the rotation axis direction of the drive roller 62. , only the guide rail 11 at one end is illustrated.

3 to 5 are schematic cross-sectional views showing a simplified configuration of the image forming apparatus 1 of FIG. 1. FIG. More specifically, FIG. 3 is a schematic cross-sectional view showing the transfer unit 5 in a monochrome contact state. 4, the door 13 is opened from the state shown in FIG. 3 to release the opening of the main body of the image forming apparatus 1, and the secondary transfer means 14 is rotated to release the secondary transfer portion N2. FIG. 2 is a schematic cross-sectional view showing a state in which FIG. 5 is a schematic cross-sectional view showing a state in which the transfer unit 5 is removed from the image forming apparatus 1. FIG. 3 is a schematic cross-sectional view for explaining removal of the transfer unit 5 in this embodiment. The removal of the transfer unit 5 from the monochrome contact state will be described below with reference to FIGS. 3 to 5.

When removing the transfer unit 5 from the image forming apparatus 1, first, the door 13 and the secondary transfer means 14 of the apparatus main body are rotated, as shown in FIG. This opens the opening, and by pulling out the transfer unit 5 in the direction of arrow A (first direction) shown in the figure, it becomes possible to remove the transfer unit 5 from the opening. At this time, the transfer unit 5 is removed from the main body of the apparatus by sliding along guide rails 11 provided at both ends of the intermediate transfer belt 9 in the width direction.

As shown in FIG. 1 and FIGS. 3 to 5, in the direction of arrow A shown in the figure, which is the pulling direction when removing the transfer unit 5, there is a transfer material P in the secondary transfer portion N2 between the transfer unit 5 and the door 13. A pre-transfer guide 15 (abutting member) is arranged for guiding. The pre-transfer guide 15 is arranged at a position close to the secondary transfer section N2 in order to guide the transfer material P at a predetermined angle and at a predetermined position with respect to the secondary transfer section N2.

In the monochrome contact state, the transfer roller 4d urges the photosensitive drum 3d via the intermediate transfer belt 9. Therefore, when removing the transfer unit 5 in the monochrome contact state from the main body of the apparatus, as shown in FIG. It stands out in terms of direction. In this embodiment, even when the transfer unit 5 is further moved in the direction of arrow A in the figure from the state shown in FIG. Regulatory measures are in place to regulate the location of The regulating means for regulating the position of the primary transfer roller 4d in this embodiment will be described below with reference to FIGS. 6(a) to 6(b).

FIG. 6A is a schematic diagram of the vicinity of the primary transfer roller 4d in the monochrome contact state before the removal operation of the transfer unit 5 is started. Further, FIG. 6(b) is a schematic diagram of the vicinity of the primary transfer roller 4d in a state where the position of the primary transfer roller 4d is regulated by the regulating means after the removal operation of the transfer unit 5 has started.

As shown in FIG. 6A, in the monochrome contact state, the primary transfer roller 4d is rotatably held at the end portion in the width direction of the intermediate transfer belt 9 by a bearing 17 as a support member. The bearing 17 is rotatably held by a rotating shaft 17a, and is biased by a spring 18 as a biasing member. Thereby, the primary transfer roller 4d is urged toward the photosensitive drum 3d via the intermediate transfer belt 9. Further, the bearing 17 is provided with a contact portion 17b that can come into contact with a guide portion 11a (support portion) provided on the guide rail 11 that supports the transfer unit 5. The contact portion 17b is slidable relative to the guide portion 11a when the transfer unit 5 is removed.

As shown in FIG. 6(b), when the transfer unit 5 is removed from the monochrome contact state, the contact portion 17b of the bearing 17 resists the biasing force of the spring 18 after contacting the guide portion 11a. It rotates around a rotating shaft 17a. Then, since the position of the primary transfer roller 4d is regulated by the bearing 17, it is possible to avoid contact between the intermediate transfer belt 9 and the pre-transfer guide 15 when the transfer unit 5 is removed.

As described above, in this embodiment, the regulating means for regulating the position of the primary transfer roller 4d includes the bearing 17, the biasing member 18, and the guide portion 11a. Here, the position of the guide portion 11a is determined based on the configuration of the bearing 17 and the arrangement of each member of the transfer unit 5 so that the intermediate transfer belt 9 and the pre-transfer guide 15 do not come into contact with each other when the transfer unit 5 is removed. are properly configured.

As described above, according to the configuration of this embodiment, when the transfer unit 5 in the monochrome contact state is removed from the image forming apparatus 1, the position of the primary transfer roller 4d can be regulated by the regulating means. be. As a result, even when the transfer unit is removed from the image forming apparatus while the transfer member is urging the photosensitive drum, the user does not need to perform a separate operation to separate the transfer member. Therefore, according to this embodiment, it is possible to remove the transfer unit 5 from the image forming apparatus 1 with a simpler operation while suppressing wear and damage of the transfer unit 5.

In this embodiment, the operation when removing the transfer unit 5 from the image forming apparatus 1 has been described, but also when attaching the transfer unit 5 to the image forming apparatus 1, the primary transfer roller 4d is It is possible to regulate the position of Thereby, it is possible to obtain effects similar to those described in this embodiment. Furthermore, when the attachment of the transfer unit 5 to the image forming apparatus 1 is completed, as shown in FIG. 6(a), the contact portion 17b of the bearing 17 and the guide portion 11a are not in contact. Become. Therefore, at the position where the attachment of the transfer unit 5 to the image forming apparatus 1 is completed, the primary transfer roller 4d is urged against the photosensitive drum 3d, and the controller 36 causes the primary transfer roller 4d to be in contact with the photosensitive drum 3d. It is also possible to switch the contact state.

In this embodiment, the contact member is a contact member disposed between the transfer unit 5 and the door 13 with respect to the removal direction of the transfer unit 5, and which can come into contact with the transfer unit 5 when removing the transfer unit 5. , the pre-transfer guide 15 has been explained as an example. However, the present invention is not limited thereto, and in the vicinity of the transfer unit 5, there may be a detection member for detecting the toner image formed on the intermediate transfer belt 9, a conveyance member for conveying the transfer material, and a cleaning member for cleaning the conveyance member. Various members may be arranged. Even in such a case, it is possible to obtain the same effects as in this embodiment by providing a regulating means as in this embodiment.

Further, in this embodiment, a case has been described in which the transfer unit 5 in the monochrome contact state is removed from the image forming apparatus 1, but the present invention is not limited to this. Even when any primary transfer roller 4, not just the primary transfer roller 4d, is biasing the photosensitive drum 3, by providing the regulating means of this embodiment, the same effect as that of this embodiment can be obtained. It is possible to obtain. Further, the structure is not limited to one in which only one primary transfer roller 4 urges the photosensitive drum 3. Even if a plurality or all of the primary transfer rollers 4 are configured to urge the photosensitive drum 3, the same configuration can be adopted for the bearing 17 of each primary transfer roller 4 as in this embodiment. It goes without saying that this effect can be obtained.

As shown in FIG. 1, in this embodiment, each primary transfer roller 4 is arranged directly below the corresponding photosensitive drum 3, and the photosensitive drum 3 and the primary transfer roller 4 are connected to each other via an intermediate transfer belt 9. The contact configuration has been explained. However, the present invention is not limited to this, and the configuration is such that the primary transfer roller 4 is arranged upstream or downstream of the primary transfer portion N1 where the photosensitive drum 3 and the intermediate transfer belt 9 are in contact with each other with respect to the moving direction of the intermediate transfer belt 9. It may be.

Furthermore, in this embodiment, the standby state in which no image formation is performed is performed by forming the primary transfer portion N1d corresponding to the photosensitive drum 3d that carries a black toner image, and by forming the other primary transfer portions N1. A configuration has been described in which a monochrome contact state is achieved in which the contact state is not set. However, the standby state is not limited to this, and may be a full color contact state or a full separation state. According to the configuration of this embodiment, the above-described effects can be obtained not only in the standby state but also when the transfer unit 5 is removed from the state where the primary transfer roller 4 is urging the photosensitive drum 3. .

In this embodiment, the guide portion 11a provided on the guide rail 11 has been described as the support portion that contacts the contact portion 17b of the bearing 17, but the guide portion 11a is not limited thereto. Any member may be used as the support part as long as it is provided in the main body of the image forming apparatus 1 and can regulate the position of the primary transfer roller 4d by coming into contact with the bearing 17.

(Example 2)
In the first embodiment, the configuration of the image forming apparatus in which the photosensitive drum 3 is disposed below the transfer unit 5 with respect to the direction of gravity has been described. In contrast, in this embodiment, a configuration of an image forming apparatus in which the photosensitive drum 3 is arranged above the transfer unit 5 in the direction of gravity will be described. In addition, in the following description, the same reference numerals are given to the parts common to the first embodiment, and the description thereof will be omitted.

FIG. 7 is a schematic cross-sectional view illustrating the configuration of the image forming apparatus 101 according to the second embodiment. As shown in FIG. 7, in this embodiment, the photosensitive drum 103 is arranged above the transfer unit 105 in the direction of gravity. The primary transfer roller 104 (transfer member) in the transfer unit 105 is arranged at the upper part of the transfer unit 105 . Further, in this embodiment, the primary transfer roller 104 is arranged offset to the upstream side in the direction of removal of the transfer unit 105 (direction of arrow A in the figure) with respect to the photosensitive drum 103. The primary transfer roller 104 is urged in a direction toward the photosensitive drum 103 via the intermediate transfer belt 9.

When removing the transfer unit 105 from the image forming apparatus 101, the door 13 and the secondary transfer means 14 of the apparatus main body are rotated as in the first embodiment. This opens the opening, and it becomes possible to pull out the transfer unit 105 in the direction of arrow A (first direction) shown in the figure and remove the transfer unit 105 from the opening. At this time, as in the first embodiment, the transfer unit 105 is removed from the apparatus main body by sliding along the guide rails 11 provided at both ends of the intermediate transfer belt 9 in the width direction.

As shown in FIG. 7, in the direction of arrow A in the figure, between the primary transfer roller 104a and the door 13, there is a fixing means 120 for fixing the toner image on the transfer material P that has passed through the secondary transfer section N2, and a photosensitive drum. A contact member such as 103a is arranged. The pre-transfer guide 15 is arranged at a position close to the secondary transfer section N2 in order to guide the transfer material P at a predetermined angle and at a predetermined position with respect to the secondary transfer section N2.

When the transfer unit 105 is pulled out in the direction of arrow A in this state, the primary transfer roller 104a and the photosensitive drum 103a come into contact with each other via the intermediate transfer belt 9, thereby preventing wear and damage of the intermediate transfer belt 9 and the photosensitive drum 103a. There is a risk that this may occur. Furthermore, if the primary transfer roller 104a and the frame of the fixing means 120 come into contact with each other via the intermediate transfer belt 9, there is a risk that the intermediate transfer belt 9 will be worn out or damaged. Therefore, in this embodiment, a regulating means is provided to regulate the position of the primary transfer roller 104a so that the transfer unit 105 and various members do not come into contact with each other. The regulating means for regulating the position of the primary transfer roller 104a in this embodiment will be described below with reference to FIGS. 8(a) to 8(b).

FIG. 8A is a schematic diagram of the vicinity of the primary transfer roller 104a before the removal operation of the transfer unit 105 is started. Further, FIG. 8(b) is a schematic diagram of the vicinity of the primary transfer roller 104a in a state where the position of the primary transfer roller 4a is regulated by the regulating means after the removal operation of the transfer unit 105 has started.

As shown in FIG. 8A, in the state before the removal operation of the transfer unit 105 in this embodiment, the primary transfer roller 104a supports the end of the intermediate transfer belt 9 in the width direction as a support member. is held by a bearing 117. The bearing 117 is biased by a spring 118 as a biasing member. Thereby, the primary transfer roller 104a is urged toward the photosensitive drum 103a via the intermediate transfer belt 9. Further, the bearing 117 can come into contact with a guide portion 111a provided on the guide rail 11 that supports the transfer unit 105, and can slide relative to the guide portion 111a when the transfer unit 5 is removed.

As shown in FIG. 8B, when removal of the transfer unit 105 is started, the bearing 117 comes into contact with the guide portion 111a and then retreats in a direction away from the photosensitive drum 103a against the biasing force of the spring 118. Then, the primary transfer roller 104a supported by the bearing 117 also moves. As a result, the position of the primary transfer roller 104a is regulated by the bearing 117, making it possible to avoid contact between the intermediate transfer belt 9 and the photosensitive drum 103a when the transfer unit 105 is removed. Furthermore, with respect to the direction in which the transfer unit 105 is pulled out, a fixing unit 120 is provided downstream of the photosensitive drum 103a. According to the configuration of this embodiment, even when the primary transfer roller 104a passes through the fixing means 120, the position of the primary transfer roller 104a is regulated by the bearing 117 and the guide portion 111a, so that the primary transfer roller 104a Contact with the fixing means 120 can be avoided.

As described above, in this embodiment, the regulating means for regulating the position of the primary transfer roller 104a includes the bearing 117, the spring 118, and the guide portion 111a. Here, the position where the guide portion 111a is arranged is determined by the configuration of the bearing 117 and the arrangement of each member of the transfer unit 105 so that the intermediate transfer belt 9 does not come into contact with the photosensitive drum 103a and the fixing means 120 when the transfer unit 105 is removed. Properly set based on your configuration.

As described above, according to the configuration of this embodiment, when the transfer unit 105 is removed from the image forming apparatus 101, the position of the primary transfer roller 104a can be regulated by the regulating means. As a result, the same effects as in the first embodiment can be obtained with the configuration of the image forming apparatus 101 of this embodiment.

In the above embodiment, the image forming apparatus 1 of an intermediate transfer type using the intermediate transfer belt 9 has been described, but the present invention is not limited to this. Even in a direct transfer type image forming apparatus having a conveyor belt that conveys the transfer material P, it is possible to obtain the same effects as in the first and second embodiments.

1 Image forming device 3 Photosensitive drum 4 Primary transfer roller 5 Transfer unit 9 Intermediate transfer belt 13 Door

Claims (12)

a photoreceptor that carries a toner image;
a movable belt; a transfer member forming a transfer section where the belt and the photoconductor come into contact; and transferring a toner image carried by the photoconductor toward the belt in the transfer section; and the transfer member. a transfer unit having a biasing member that biases the photoreceptor toward the photoreceptor;
an opening/closing door provided in an opening for removing the transfer unit;
In an image forming apparatus, the transfer unit can be removed from the opening in a first direction,
a contact member disposed between the transfer unit and the door in the first direction when the door is closed;
When the transfer unit is removed from the image forming apparatus with the transfer unit being formed by the transfer member being urged by the urging member, the belt and the abutting member are prevented from coming into contact with each other. a regulating means for regulating the movement of the transfer member against the biasing force of the biasing member;
a support member that supports an end of the transfer member in the width direction of the belt perpendicular to the moving direction of the belt and is biased by the biasing member;
a support part that is capable of contacting the support member and is provided on the main body of the image forming apparatus;
Equipped with
The regulating means includes the support member, the support part, and the biasing member, and after the support member and the support part are in contact with each other, the biasing member is activated in a state where the support member supports the transfer member. An image forming apparatus characterized in that movement of the transfer member is regulated by moving against an urging force of the transfer member . The support member includes a contact portion that contacts the support portion, and a rotation shaft that rotates against the biasing force of the biasing member when the support portion and the contact portion contact each other. The image forming apparatus according to claim 1 , characterized in that it has: 2. The support member, by contacting the support portion, retreats in a direction that resists the biasing force of the biasing member while supporting the end portion of the transfer member. image forming device. 4. The supporting portion is provided in a guide portion that supports an end portion of the transfer unit in the width direction and guides the transfer unit when the transfer unit is removed. The image forming apparatus according to item 1. 5. The image forming apparatus according to claim 1, wherein the contact member is a guide member that guides the transfer material toward the belt. 6. Any one of claims 1 to 5 , further comprising another photoreceptor different from the photoreceptor, the photoreceptor being provided at a position closest to the opening/closing door with respect to the first direction. The image forming apparatus described in . The control means includes a first state in which the photoreceptor and the other photoreceptor are in contact with the belt, and a state in which only the photoreceptor is in contact with the belt. 7. It is possible to switch between a second state in which the photoreceptor is in contact with the belt and a third state in which no photoreceptor is in contact with the belt. The image forming apparatus described in . 8. The image forming apparatus according to claim 7 , wherein the control means sets the state of the transfer unit to the second state during standby in which no image forming operation is performed. The image forming apparatus according to any one of claims 1 to 8 , wherein the photoreceptor carries black toner. The image forming apparatus according to any one of claims 1 to 9 , wherein the photoreceptor is disposed below the transfer unit in the direction of gravity. The belt is an intermediate transfer belt, and the toner image carried on the photoreceptor is primarily transferred from the photoreceptor to the intermediate transfer belt, and then secondarily transferred from the intermediate transfer belt to a transfer material. The image forming apparatus according to any one of claims 1 to 10 . The belt is a conveyance belt that conveys a transfer material, and the toner image carried on the photoreceptor is transferred to the transfer material conveyed by the conveyance belt in order to be superimposed. 10. The image forming apparatus according to any one of 10 to 10.

Images