JP4179897B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus having a replaceable intermediate transfer unit such as a laser printer or a digital copying machine.
[0002]
[Prior art]
Recently, image forming apparatuses such as copiers and printers have become as widespread as home appliances, and appliances have become important as product differentiation items. Further, since the image forming apparatus is designed to maintain a good use state by exchanging the components constituting the apparatus, the ease of component replacement is also an important item.
[0003]
In the image forming apparatus, normally, the inside of the apparatus is unitized, and the lifetime is set for each unit, and the unit may be replaced for each unit according to the degree of wear (for example, Patent Document 1). reference.).
[0004]
[Patent Document 1]
JP 2000-194203 A (paragraph [0016], FIG. 2)
[0005]
[Problems to be solved by the invention]
However, there are many cases where a unit is not independent and there are cases where the units are in contact with each other and are pressed against each other. It was necessary to perform some operations such as opening the door, and the operation was complicated.
[0006]
Also, since the operation to open each unit is not uniform, the operator may forget the necessary operation.In that case, when trying to take out the unit to be replaced, the adjacent unit or the device main body will be damaged. There was a case to give. This problem also occurred when the user forgot to perform the necessary recovery operation and replaced the unit door.
[0007]
An example of a unit opening operation at the time of unit replacement will be described with reference to FIGS.
FIG. 4 is a cross-sectional view showing a configuration of a full-color printer having a conventional intermediate transfer unit in the apparatus housing.
Inside the casing of the full-color printer 90, there are four drum-shaped photoreceptors 3Y, 3M, 3C, and 3Bk, which are image carriers, in a substantially central portion, and laser light corresponding to image data for each color is uniformly below. An exposure device 8 is provided to scan the charged photoreceptors 3Y, 3M, 3C, and 3Bk to form an electrostatic latent image, and an intermediate transfer is provided above the photoreceptors 3Y, 3M, 3C, and 3Bk. The belt 12 is moved endlessly while being stretched, and the intermediate transfer unit 15 is arranged so that it can be pulled out in the front (operator side) direction in the figure, and the transfer belt 17 is stretched on the right side of the intermediate transfer unit 15 in the figure. A transfer belt unit 20 for endless movement is provided. Further, during normal use, the transfer belt 17 is in contact with the intermediate transfer belt 12 so as to form a predetermined transfer nip pressure at the roller 9 portion, and the transfer sheet S is in contact with the intermediate transfer belt 12 and the transfer belt 17. The toner image on the intermediate transfer belt 12 is transferred to the transfer paper S when passing through the contact portion, and is color-printed.
[0008]
In the full-color printer 90, when the intermediate transfer unit 15 is to be replaced, the transfer belt 17 is separated from the intermediate transfer belt 12, the built-in intermediate transfer unit 15 is pulled out from the apparatus housing, and then a new one is obtained. It is necessary to store the intermediate transfer unit 15 in the same position and bring the transfer belt 17 into contact with the intermediate transfer belt 12 again.
[0009]
Specifically, when the intermediate transfer unit 15 is replaced, the following operation is performed.
FIG. 5 is an external view showing a state of the full-color printer 90 during normal use. All openable doors such as the front door 45 and the right cover 61 of the full color printer 90 are closed.
(1) In order to separate the transfer belt 17 from the intermediate transfer belt 12, the transfer belt unit 20 is rotated together with the right cover 61 by opening the right cover. As shown in FIG. 6, the right cover 61 is opened from the printer main body by rotating clockwise around the rotation shaft 62 in the drawing. In this state, the transfer belt unit 20 is greatly separated from the intermediate transfer unit 15 fixed on the apparatus main body side, and a transfer nip is not formed.
(2) Next, the front door 45 is opened in the front (operator side) direction of the apparatus, and the support on which the intermediate transfer unit 15 is mounted is pulled out in the front (operator side) direction of the apparatus. Pull out from the housing. As a method of pulling out, the intermediate transfer unit 15 is released from being fixed to the apparatus housing by operating an operation lever provided on a support body on which the intermediate transfer unit 15 is mounted, and then on the guide rail. There is a system in which the intermediate transfer unit 15 is exposed from the apparatus housing together with the support by pulling a lever provided on the support in front of the apparatus (operator side) and sliding the support on a guide rail.
(3) The intermediate transfer unit 15 on the support is removed, and a new intermediate transfer unit 15 is mounted at the same position.
(4) The intermediate transfer unit 15 is accommodated together with the support at a predetermined accommodation position in the apparatus casing in the reverse order of the operation of (2).
(5) The right cover 61 is closed, and the intermediate transfer belt 12 and the transfer belt 17 are brought into contact with each other by storing the transfer belt unit 20 in a predetermined storage position in the apparatus housing.
[0010]
As described above, the exchange operation of the intermediate transfer unit is a complicated operation because there are procedures determined as several operations. Further, for example, when the operator neglects the procedure (1) and starts the operation of the procedure (2), the intermediate transfer unit 15 is moved with the intermediate transfer belt 12 and the transfer belt 17 in contact with each other. Therefore, if the operator forcibly pulls out the intermediate transfer unit 15, not only the damage of the intermediate transfer belt 12 but also other parts of the intermediate transfer unit 15, the transfer belt unit 20, or those units are supported. Even the component members of the device casing that was installed were sometimes damaged.
[0011]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus in which a unit housed in the apparatus can be taken out of the apparatus with a simple operation.
[0012]
[Means for Solving the Problems]
An image forming apparatus according to the invention of claim 1 provided to solve the above-described problem is disposed in an image carrier that carries a toner image on a surface thereof, and a unit storage portion that is arranged in the apparatus housing, and can be freely inserted and removed. An intermediate transfer unit having an intermediate transfer member to which a toner image on the image carrier is transferred; and a second transfer unit that is brought into contact with the intermediate transfer member with a predetermined pressure. The intermediate transfer unit and the second transfer unit In the image forming apparatus for transferring the toner image onto a transfer paper inserted between the second transfer unit and the second transfer unit, the second transfer unit is arranged to be urged in a direction opposite to the pressure direction of the second transfer unit with respect to the intermediate transfer member. An arm jig that covers the apparatus housing so as to be openable and closable, and an apparatus door having a protrusion protruding on the inner side of the apparatus housing. The second transfer means is attached in a direction opposite to the pressure direction . Away from the intermediate transfer member To be able to provided,
When the device door is closed, the protrusion acts on the arm jig to stop the bias to the second transfer means, so that the second transfer means comes into contact with the intermediate transfer body, and the door opens. The second transfer unit is separated from the intermediate transfer member by detaching the portion from the arm jig and biasing the second transfer unit by the arm jig .
According to a second aspect of the present invention, there is provided an image forming apparatus according to the second aspect of the present invention, wherein the arm jig is rotatably supported by the main body of the apparatus and the intermediate transfer of the second transfer means. A shaft arranged in parallel with the contact surface with the body, an arm made up of an arm portion and a taper portion fixed in the vicinity of the end portion of the shaft on the apparatus door side and abutting against and energizing the second transfer means And an elastic body having one end fixed to one end of the taper portion and the other end fixed to the apparatus housing, and the arm is rotated about the axis by the elastic force of the elastic body. In addition, the arm portion of the arm is in contact with the second transfer means and acts to urge the second transfer means in the direction opposite to the pressure direction, and the protrusion acts on the taper portion of the arm. Due to the above, the protruding portion resists the taper portion against the elastic force. Characterized by stopping the energization of the second transfer means by rotating in the direction.
[0013]
According to the first and second aspects of the invention, the intermediate transfer unit can be taken in and out by a simple operation of only opening and closing the apparatus door. Therefore, it is possible to avoid damage to the unit and the apparatus housing without forgetting the operation when the operator replaces the intermediate transfer unit.
Here, the intermediate transfer member is a second image carrier that transfers a toner image formed thereon from a photosensitive member (first image carrier) and transfers the toner image onto a transfer paper or the like. In a printer, an intermediate transfer belt which is an endless moving body corresponds to this. Further, the second transfer means is disposed on the opposite side of the intermediate transfer body with the transfer paper sandwiched at the position where the toner image is transferred to the transfer paper, and contacts the intermediate transfer body with a predetermined nip pressure. For example, a transfer belt unit including a transfer belt and a plurality of rollers corresponds to this. In the case of double-sided image formation, the second transfer unit serves as a third image carrier that transfers the toner image from the intermediate transfer belt to the back surface of the transfer paper.
[0016]
According to a third aspect of the present invention, there is provided an image forming apparatus according to a third aspect of the present invention, wherein the second transfer means is a transfer roller.
According to a fourth aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect, wherein the second transfer means is a transfer brush.
An image forming apparatus according to a fifth aspect of the invention provided to solve the above-mentioned problems is characterized in that, in the first or second aspect of the invention, the second transfer means is a transfer film.
According to a sixth aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect, wherein the second transfer unit is a transfer belt.
An image forming apparatus according to a seventh aspect of the present invention provided to solve the above-mentioned problem is the invention according to any one of the first to sixth aspects, wherein the intermediate transfer unit and the second transfer means are disposed between the intermediate transfer unit and the second transfer unit. The transfer paper conveyance path is substantially perpendicular to the horizontal plane.
[0017]
According to the third to sixth aspects, the present invention according to the first or second aspect can be applied to image forming apparatuses having various configurations. Note that the second transfer means is a third image carrier and has a resistance value that enables transfer of the toner image from the intermediate transfer member, and by controlling the transfer timing of the toner image on the intermediate transfer member, It is also possible to use an apparatus for forming
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of an image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. However, the configuration described below is an example, and the present invention is not limited to this.
FIG. 1 is a cross-sectional view showing the configuration of an image forming apparatus according to an embodiment of the present invention. Inside the housing of the full-color printer 1 that is an image forming apparatus, there are four drum-shaped photoconductors 3Y, 3M, 3C, and 3Bk that are image carriers for forming a color image, and image formations attached to them. A member, an exposure device 8 for forming a latent electrostatic image by irradiating a laser beam corresponding to image data for each color to the uniformly charged photoreceptors 3Y, 3M, 3C, and 3Bk, and a first endless An intermediate transfer unit 15 that moves the intermediate transfer belt 12 as a moving body endlessly while stretching, a transfer belt unit 20 that moves endlessly while the transfer belt 17 as a second endless moving body is stretched, and the transfer belt unit 20 are pressed. The arm jig 100 acting as described above, the fixing device 31 for fixing the toner image transferred from the intermediate transfer unit 15 to the transfer paper S, and the transfer paper S are collected. Sheet feeding cassettes 23 and 24, a sheet feeding conveyance path 27 for conveying the transfer sheet S to the intermediate transfer unit 15, and a conveyance sheet discharging path for discharging the transfer sheet S on which the toner image is transferred to the sheet discharge tray 29. 30. Further, as shown in FIG. 3, the full-color printer 1 is provided with a front door 45 having a protruding portion 101 that protrudes to the inside of the apparatus housing 103.
[0019]
The photoconductors 3Y, 3M, 3C, and 3Bk are arranged in parallel at a substantially central portion of the full-color printer 1 in a horizontal state and spaced apart at equal intervals in the left-right direction in the drawing. The subscripts Y, M, C, and Bk indicate yellow, magenta, cyan, and black, respectively. When paying attention to the photoreceptor 3Y for yellow image, this photoreceptor 3Y has a structure in which an organic semiconductor layer as a photoconductive material is provided on the surface of an aluminum cylinder having a diameter of about 30 to 100 mm, for example, and is driven to rotate clockwise. An image forming member such as a charging roller 4Y, a developing roller 5Y, and a cleaning member 7Y is sequentially disposed around the periphery in accordance with an electrophotographic process. The magenta, cyan, and black photoconductors 3M, 3C, and 3Bk have the same configuration except that the color of the toner used is different. In addition, a belt-shaped photoconductor can be used.
[0020]
The exposure device 8 is provided below the photoreceptors 3Y, 3M, 3C, and 3Bk, and laser light irradiated by the exposure device 8 is provided between the charging rollers 4 and the developing rollers 5 to the photoreceptors. An elongated space (slit) is secured so as to enter 3Y, 3M, 3C, and 3Bk. Although the illustrated example is shown as a laser scanning method using a laser light source, a polygon mirror, etc., an exposure apparatus combining an LED array and an image forming means may be used.
[0021]
The intermediate transfer unit 15 is disposed above the photoreceptors 3Y, 3M, 3C, 3Bk. The intermediate transfer unit 15 includes an intermediate transfer belt 12, four transfer rollers 13Y, 13M, 13C, and 13Bk, a cleaning device 14, and the like. A transfer backup roller 9, a tension roller 10, a cleaning backup roller 11 and the like are also provided. The intermediate transfer belt 12 is a second image carrier, and is endlessly moved in the counterclockwise direction in the figure by the rotational drive of at least one roller while being supported by these three rollers. The intermediate transfer belt 12 is common to the photoreceptors 3Y, 3M, 3C, and 3Bk, and is almost in contact with a part of each photoreceptor 3Y, 3M, 3C, and 3Bk after the developing process. The transfer rollers 13Y, 13M, 13C, and 13Bk are provided on the inner periphery of the belt so as to face the photoreceptors 3Y, 3M, 3C, and 3Bk. A cleaning device 14 is provided on the outer peripheral portion of the intermediate transfer belt 12 at a position facing the cleaning backup roller 11, for example. The cleaning device 14 acts to wipe off unnecessary toner remaining on the surface of the intermediate transfer belt 12. The intermediate transfer belt 12 is a belt based on, for example, a resin film or rubber having a base thickness of 50 to 600 μm, and a resistance that enables transfer of toner images from the photoreceptors 3Y, 3M, 3C, and 3Bk. Has a value.
[0022]
The transfer belt unit 20 is disposed on the right side of the intermediate transfer unit 15 in the drawing. The transfer belt unit 20 includes a transfer belt 17, a plurality of rollers 18, 110, 111, and the like. The transfer belt 17 is endlessly moved in the clockwise direction in the figure by the rotational drive of at least one of the rollers while being stretched by the rollers 110 and 111. Further, the transfer belt 17 is in contact with the intermediate transfer belt 12 so as to form a predetermined transfer nip at the roller 9 portion, and the rollers 110, 110 are formed so that the cross-sectional shape thereof becomes a flat shape extending in a substantially vertical direction. 111 is arranged together. The transfer belt unit 20 is configured to be rotatable about a roller 110, and is normally in contact with the intermediate transfer belt 12 as described above, and the vicinity of the roller 111 resists the transfer nip pressure, and the intermediate transfer unit. The transfer belt 17 rotates so as to be separated from the intermediate transfer belt 12 by being urged and pressed in a direction substantially perpendicular to the drawing direction of 15.
[0023]
The transfer belt 17 is a belt having a base of, for example, a resin film or rubber having a base thickness of 50 to 600 μm, like the intermediate transfer belt 12. In the present embodiment, the transfer belt 17 is shown as having a belt shape, but other than this, a roller shape, a brush shape, or a film shape may be used.
[0024]
The arm jig 100 is disposed on the lower side of the intermediate transfer unit 15 in the drawing and on the left side of the transfer belt unit 20 in the drawing. As shown in FIG. 2, the arm jig 100 is rotatably supported by the apparatus housing, and is provided with a shaft 106 disposed parallel to the main surface of the transfer belt 17 of the transfer belt unit 20 and the shaft of the roller 111, and the shaft 106. Arms 104 and 105 are fixed in the vicinity of both ends, respectively, and a spring 107 which is an elastic body having one end fixed to one end of the arm 104 and the other end fixed to the apparatus housing. The arm 104 has a substantially central portion fixed to the shaft 106, and a taper portion 104a having a thickness decreasing toward the end of the shaft 106 is formed on the side of the arm 104 where the spring 107 is fixed. The arm 105 is fixed to the shaft 106 so that the arm is parallel to the arm portion 104 b of the arm 104.
[0025]
The arm 104b of the arm 104 is in contact with the front side (operator side) of the transfer belt unit 20 and the arm 105 is in contact with the back side of the transfer belt unit 20 (drive side). . The shaft 106 connects the arm 104 and the arm 105 to synchronize contact with the transfer belt unit 20. The spring 107 is for applying pressure in a direction in which the transfer belt unit 20 is separated from the intermediate transfer unit 15 when the arms 104 and 105 come into contact with the transfer belt unit 20.
[0026]
The arm lengths of the arms 104 and 105 are determined by the distance from the shaft 106 to the transfer belt 17, the elastic force and length of the spring 107, the positional relationship between the position of the spring 107 fixed to the apparatus housing and the shaft 106, and the like. Is done. The length of the arm 104b of the arm 104 is the same as the length of the arm 105, and is long enough to support the transfer belt 17 in a state where the transfer belt unit 20 is pressed and separated from the intermediate transfer belt 12. .
[0027]
The paper feed cassettes 23 and 24 are arranged in a plurality of stages, for example, two stages, so that they can be pulled out below the exposure apparatus 8 in the apparatus casing. The transfer paper S stored in the paper feed cassettes 23 and 24 is selectively fed by the corresponding paper feed rollers 25 and 26, and is directed to a transfer position by the intermediate transfer belt 12 and the transfer belt 17. Thus, the paper feed path 27 is formed substantially vertically. In the paper feeding / conveying path 27, a pair of registration rollers 28 are provided immediately before the transfer position to take the timing of paper feeding to the transfer position. Further, a conveyance / discharge path 30 is formed above the transfer position so as to be continuous with the sheet supply / conveyance path 27 and connected to the discharge stack unit 29 at the upper part of the apparatus housing. A fixing device 31 having a pair of fixing rollers, a pair of paper discharge rollers 32, and the like are disposed in the transport paper discharge path 30.
[0028]
As shown in FIG. 3, the front door 45 is provided with a protrusion 101 having a shape that gradually decreases in diameter toward the tip, on the inner surface side of the front door 45, and when the door 45 is closed, the protrusion 101 Is inserted into the inside 103 a of the apparatus housing 103, abuts against the tapered portion 104 a of the arm jig 100, and rotates the arms 104 and 105 around the shaft 106.
[0029]
In color printing, processing similar to that of a conventional image processing apparatus is performed. That is, the toner images formed on the photoreceptors 3Y, 3M, 3C, and 3Bk are sequentially transferred to the same position on the intermediate transfer belt 12 to form a full color toner image, and then the full color toner image on the intermediate transfer belt 12 is formed. The toner image is transferred onto the transfer paper S on the transfer belt 17 that moves in synchronization with the movement of the intermediate transfer belt 12, and the transfer paper S is subjected to fixing processing by the fixing device 31 and then discharged by the paper discharge roller 32. The paper is discharged onto the paper stack unit 29 and printing is completed. At this time, since the projection 101 of the front door 45 abuts against the tapered portion 104a, the arms 104 and 105 are rotated counterclockwise in FIG. 1 against the elastic force of the spring 107. Reference numeral 105 denotes a state away from the transfer belt unit 20.
[0030]
Next, an operation for exchanging the intermediate transfer unit 15 related to the present invention will be described with reference to FIGS.
(1) Open the front door 45 of the full-color printer 1 toward the front of the apparatus (operator side). As a result, the protruding portion 101 moves away from the tapered portion 104 a of the arm jig 100, so that the arms 104 and 105 rotate around the shaft 106 in the clockwise direction in the figure by the elastic force of the spring 107, and the arm portion 104 b of the arm 104. And the arm 105 abut against the transfer belt unit 20 and are urged in a direction substantially perpendicular to the drawing-out direction of the intermediate transfer unit 15.
(2) By the urging of the arms 104 and 105, the transfer belt unit 20 rotates around the roller 110, and the transfer belt 17 is separated from the intermediate transfer belt 12.
(3) The intermediate transfer unit 15 is pulled out from the apparatus housing by exposing the support on which the intermediate transfer unit 15 is mounted along the guide rail toward the apparatus (operator side).
(4) The intermediate transfer unit 15 on the support is removed, and a new intermediate transfer unit 15 is mounted at the same position.
(5) The intermediate transfer unit 15 is housed together with the support in a predetermined housing position in the apparatus housing in the reverse order of the operation of (3).
(6) Close the front door 45. As a result, the protruding portion 101 is inserted into the inside 103 a of the apparatus housing 103, abuts against the tapered portion 104 a of the arm jig 100, and the tapered portion 104 a is rotated in a direction against the elastic force of the spring 107 to transfer By stopping the urging of the arms 104 and 105 to the belt unit 20, the transfer belt 17 is brought into contact with the intermediate transfer belt 12 to be in a transfer nip state.
As described above, the intermediate transfer unit 15 can be replaced simply by opening and closing the front door 45.
[0031]
Moreover, in the said structure, although the structural example which provided the projection part 101 in the front door 45 was shown, you may make it arrange | position the projection part 101 to an in / out operation lever. In other words, the protrusion 101 is arranged to act on the tapered portion 104 a of the arm 104 when the insertion / removal lever is inserted into the intermediate transfer unit 15. As a result, the protrusion 101 rotates the tapered portion 104a in a direction against the elastic force of the spring 107 by the insertion / removal operation lever insertion operation, and the urging of the arms 104, 105 to the transfer belt unit 20 is stopped. As a result, the transfer belt 17 can be brought into contact with the intermediate transfer belt 12 to be in a transfer nip state.
On the contrary, the protrusion 101 is disengaged from the tapered portion 104 a of the arm 104 by the pulling-out operation of the loading / unloading operation lever, the arm 104 is rotated by the elastic force of the spring 107, and the arm portion 104 b and the arm 105 are in contact with the transfer belt unit 20. By energizing, the transfer belt 17 can be separated from the intermediate transfer belt 12.
In the above example, an image is formed on one side of the transfer sheet S. However, the transfer belt unit 20 includes a second cleaning device, a transfer charger, a waste toner container, and the like. The apparatus has a resistance value that enables transfer of the toner image from the intermediate transfer belt 12 as a three-image carrier and controls the transfer timing of the toner image on the intermediate transfer belt 12 to form a double-sided image. Is also possible.
[0033]
【The invention's effect】
As described above, according to the first and second aspects of the invention, the intermediate transfer unit can be taken in and out by a simple operation of only opening and closing the apparatus door, and the operation can be performed when the operator replaces the intermediate transfer unit. Without forgetting, damage to the unit or the device casing can be avoided .
According to the third to sixth aspects, the invention according to the first or second aspect can be applied to image forming apparatuses having various configurations.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration in an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is a perspective view showing a configuration in an embodiment of an arm member of the image forming apparatus according to the present invention.
FIG. 3 is an external view showing a state where the front door of the image forming apparatus according to the present invention is opened.
FIG. 4 is a cross-sectional view illustrating a configuration of a conventional image forming apparatus.
FIG. 5 is an external view of a conventional image forming apparatus.
FIG. 6 is an external view showing a state in which a right cover of a conventional image forming apparatus is opened.
[Explanation of symbols]
1,90 Full-color printers 3Y, 3M3C, 3Bk Photoreceptor 8 Exposure device 9, 10, 11, 18, 25, 26, 32, 110, 111 Roller 12 Intermediate transfer belt 13Y Transfer roller 14 Cleaning device 15 Intermediate transfer unit 17 Transfer belt 20 Transfer belt units 23 and 24 Paper feed cassette 27 Paper feed transport path 28 Registration roller 29 Paper discharge stack section 30 Paper discharge transport path 31 Fixing device 33 Toner bottle 45 Front door 61 Right cover 100 Arm jig 101 Projection section 103 Device housing Body 103 Inside housing 104, 105 Arm 104a Taper 104b Arm 106 Shaft 107 Spring

Claims (7)

An image bearing member for bearing a toner image on the surface, is out freely arranged in the unit housing portion arranged on the apparatus housing, an intermediate transfer unit having an intermediate transfer member the toner image on the image bearing member is transferred And an image forming apparatus for transferring the toner image onto a transfer sheet inserted between the intermediate transfer unit and the second transfer means. ,
An arm jig arranged to bias the second transfer means in a direction opposite to the pressure direction of the second transfer means with respect to the intermediate transfer body, and an apparatus housing that can be opened and closed, and an inner side of the apparatus housing A device door having a protruding portion protruding from the
The second transfer means is provided so as to be separated from the intermediate transfer member by urging in the direction opposite to the pressure direction ,
When the device door is closed, the protrusion acts on the arm jig to stop the bias to the second transfer means, so that the second transfer means comes into contact with the intermediate transfer body, and the door opens. An image forming apparatus, wherein the second transfer unit is separated from the intermediate transfer member when the part is detached from the arm jig and the arm jig biases the second transfer unit. The arm jig is rotatably supported by the apparatus main body and fixed to a shaft disposed in parallel with the contact surface of the second transfer means with the intermediate transfer member, and near the end of the shaft on the apparatus door side. And an arm composed of an arm portion and a tapered portion that abuts against and urges the second transfer means, and an elastic body having one end fixed to one end of the tapered portion and the other end fixed to the apparatus housing.
The arm is rotated by the elastic force of the elastic body about the axis, and the arm portion of the arm is in contact with the second transfer means to move the second transfer means in a direction opposite to the pressure direction . Acting to energize,
The projection acts on the tapered portion of the arm, and the projection stops the biasing of the second transfer means by rotating the tapered portion in a direction against an elastic force. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the second transfer unit is a transfer roller.   The image forming apparatus according to claim 1, wherein the second transfer unit is a transfer brush.   The image forming apparatus according to claim 1, wherein the second transfer unit is a transfer film.   The image forming apparatus according to claim 1, wherein the second transfer unit is a transfer belt.   The image forming apparatus according to claim 1, wherein a transfer paper conveyance path between the intermediate transfer unit and the second transfer unit is substantially perpendicular to a horizontal plane. .

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