JP2004199091A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve maintenance operability of a storage case capable of storing residues of a visual image on an image carrier on condition of a mode that a transfer unit is arranged in a rotary support unit. <P>SOLUTION: The image forming apparatus equipped with the image carrier carrying the visual image, the transfer unit (secondary transfer unit 52) which is pressed against the surface side of the image carrier across a recording material to transfer the visual image on the image carrier to the recording material at a time, and the storage case (belt cleaner 53) capable of storing residues of the visual image on the image carrier, is equipped with the rotary support unit (door unit 70) which is provided rotatably at a side part of an image forming apparatus main body and can freely be opened and closed with respect to the image forming apparatus while holding the transfer unit 52 and a door (side door 610) which is provided in a free opening/closing state at a side part of the image forming apparatus main body and in which the storage case 53 can be taken out first when opened. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine and a printer, and more particularly, to an improvement in an image forming apparatus in which a transfer unit is provided on a rotation support unit that is supported by rotation on an image forming apparatus main body.

As a conventional image forming apparatus, for example, an intermediate transfer type image forming apparatus will be described. For example, a predetermined color component image (a toner image in the case of an electrophotographic method) is formed on a latent image carrier such as a photosensitive drum. After the color component image on the latent image carrier is primarily transferred to an intermediate transfer member such as an intermediate transfer belt, the color component image on the intermediate transfer member is collectively transferred to a recording material by a transfer unit for secondary transfer. A secondary (transfer) type is already provided.
As this type of transfer unit, for example, a transfer unit in which a transfer roll is rotatably supported by a unit case and the unit case is supported by a door unit (provided to be freely openable and closable in the main body of the image forming apparatus) is known. ing.
Further, since there is a concern that untransferred toner or the like may adhere to the transfer roll, a mode in which a cleaning member is provided as a transfer unit for cleaning the transfer roll is already known.

By the way, a member such as a door unit of the image forming apparatus main body is often a module having low rigidity and poor positional accuracy from the viewpoint of weight reduction, and the transfer unit is not positioned with respect to the module. Usually, a state in which a backup roll (opposite roll) of the intermediate transfer body is brought into contact with a predetermined nip area is set as an operation position for image formation and is positioned.
Further, when the image forming step of the image forming apparatus is four cycles, or when there is a concern that a long-term contact state may lead to deformation of the transfer roll depending on the material of the transfer roll, a cycle other than the cycle of transferring to the recording material may be used. Alternatively, when the power supply is turned off, a method is often employed in which the transfer roll is made to stand by at a retract position separated from the set position.

Further, in the above-described image forming apparatus of the transfer roll type, a measure is taken that the transfer condition is not deteriorated by the change of the nip pressure of the transfer roll.
For example, a technique for positioning the transfer unit on the intermediate transfer unit with a positioning pin or the like (for example, see Patent Documents 1 and 2), or a method in which a repulsive force is generated from the intermediate transfer body side when the transfer roll is pressed, so that the transfer roll is pressed before and after pressing. A technique (for example, see Patent Document 3) for preventing a change in transfer conditions due to a movement of the position of a transfer body has already been proposed.

Japanese Patent Application Laid-Open No. 11-24528 (Example, FIG. 5) JP-A-10-293478 (Embodiment of the invention, FIG. 2) JP-A-11-265123 (Embodiment of the invention, FIG. 1)

However, in a mode in which the transfer unit is provided on a rotation support unit such as a door unit, the following technical problem has been found.
For example, in an intermediate transfer type image forming apparatus as disclosed in Patent Document 1, a cleaner for cleaning residual toner is often provided around a photoreceptor drum or an intermediate transfer belt. Since the waste toner is collected, an operation of collecting the waste toner such as replacing the cleaner is usually required.
In such a situation, for example, when the transfer unit is replaced, the transfer unit may be attached and detached by opening a door unit rotatably provided in the image forming apparatus main body. For example, when replacing the cleaner through the opening of the same door unit, it is necessary to remove the transfer unit located at least on the door unit side from the cleaner and then pull out the cleaner. There is a technical problem that it becomes troublesome.

Note that such a technical problem occurs not only in the intermediate transfer type image forming apparatus but also in an image forming apparatus in which the transfer unit is provided in the rotation support unit.
The present invention has been made in order to solve the above technical problem, and is based on the premise that a transfer unit is provided on a rotation support unit, in which a residue of a visible image on an image carrier is stored. An object of the present invention is to provide an image forming apparatus capable of improving the maintenance workability of a possible storage case.

That is, the present invention provides an image carrier that carries a visible image, a transfer unit that presses the surface of the image carrier through a recording material, and collectively transfers the visible image on the image carrier to the recording material. An image forming apparatus comprising: a housing case capable of housing a residual of a visible image on an image carrier; an image forming apparatus rotatably provided on a side of an image forming apparatus main body and holding a transfer unit. A rotating support unit that is openable and closable with respect to the forming apparatus main body, and a door that is provided on the side of the image forming apparatus main body so as to be openable and closable and that allows the housing case to be taken out first when opened. I do.
Here, the storage case may be any container that can store the residue of the visible image on the image carrier, and a housing of a cleaner that directly stores the residue on the image carrier (third embodiment) ), Or a unit case of the transfer unit (corresponding to the unit case 521 of the first embodiment) for indirectly storing the residue on the image carrier.

In such technical means, as a typical mode of the image forming apparatus, an image carrier includes a plurality of photosensitive drums and a belt unit arranged opposite thereto, and a transfer unit is arranged facing the belt unit. Are included.
Regarding the layout of the door and the rotation support unit, the door is provided on the other side of the image forming apparatus main body opposite to the rotation support unit provided on one side of the image forming apparatus main body. preferable. In this case, maintenance work around the transfer unit and the housing case can be individually performed.
Further, for example, in a mode in which a plurality of photosensitive drums and a belt unit are provided, the use of the door is such that the belt unit can be pulled out horizontally from the side of the image forming apparatus main body through the opening when the door is opened. Is preferred.
In an embodiment including this type of belt unit, the storage case may be, for example, one that collects a visible image residue on the belt unit.

Further, in the embodiment in which the transfer unit is provided on the rotation support unit as in the present invention, the embodiments shown in FIGS. 1A to 1C are preferable.
The first aspect is an improvement in blowing of cleaning residues such as a toner cloud. As shown in FIG. 1A, the image forming engine 1 includes an image carrier 2 that carries a visible image. And a transfer member 3a which is pressed against the surface of the image carrier 2 via a recording material and collectively transfers the visible image on the image carrier 2 to the recording material. Hereinafter, in the section of [Means for Solving the Problems], the rotation supporting unit 5 is rotatably supported with respect to the apparatus body 4, the transfer member 3a, and the cleaning member 3b for cleaning the transfer member 3a. And a transfer unit 3 incorporating the transfer unit 3 into the unit case 3c so that the transfer member 3a can be moved toward and away from the image carrier 2 with respect to the rotation support unit 5 together with the unit case 3c. That you can move freely It is an butterfly.

  A conventional transfer unit mounting structure is such that, as shown in FIGS. 23A and 23B, for example, a transfer unit 810 is disposed on a door unit 800 having a rotation fulcrum 801, and the transfer unit 810 includes a door. A transfer roll 812 is provided in an opening of a unit case 811 fixed to the unit 800, and a cleaning brush 813 that contacts the transfer roll 812 is provided in the unit case 811. Further, the transfer roll 812 is retracted. The transfer roller 812 is supported by a swing arm 822 that swings with an eccentric cam 821, and the transfer arm 822 is retractably supported by a biasing spring 823 in a predetermined direction. It is like that. In FIGS. 23A and 23B, reference numeral 830 denotes a belt unit having an intermediate transfer belt 831, and a backup roll 832 serving as a stretching roll is provided on the back surface of the intermediate transfer belt 831 facing the transfer roll 812. ing.

In this type of mode, the transfer roll 812 is swingably supported by the swing arm 822 in order to enable the retraction operation of the transfer roll 812. Therefore, the swing locus of the transfer roll 812 is inevitably determined. It is indispensable to secure a wide opening area of the unit case 811 in consideration of the above.
For this reason, a relatively wide gap is formed between the opening of the unit case 811 and the transfer roll 812. For example, as shown in FIG. 23A, the transfer roll 812 is moved between the set position and the retract position. There is a concern that the toner cloud 840 may blow out from the gap of the unit case 811 under the condition of moving between the unit cases 811.
Further, as shown in FIG. 23B, the door unit 800 is opened and the work is performed at the time of jam clearance and maintenance, but when the door unit 800 is opened and closed, the unit case 811 of the transfer unit 810 is opened and closed. There is a concern that the toner cloud 840 may blow out from the gap.

On the other hand, according to the first aspect (see FIG. 1A), the retracting operation of the transfer member 3a alone is eliminated and the retracting operation is performed for each unit case 3c, so that the opening width of the unit case 3c is minimized. It is possible to prevent the cleaning residue from blowing out from the unit case 3c.
As described above, according to the first aspect, the transfer member and the cleaning member are incorporated in one unit case, and the transfer unit is movable with respect to the rotation support unit. The relative movement of the transfer member is eliminated, and accordingly, the opening area of the unit case can be set according to the size of the transfer member, and the gap between the unit case and the transfer member can be minimized. .
For this reason, even if the transfer unit is moved toward or away from the transfer unit, or if the opening / closing operation of the rotation support unit is performed during jam clearance or maintenance, the cleaning residue in the unit case cleaned by the cleaning member is unnecessarily blown out of the opening gap. The situation can be effectively prevented, and adverse effects such as contamination of the recording material due to blowing of the cleaning residue can be effectively avoided.

In such technical means, this embodiment is based on the premise that the transfer member 3a and the cleaning member 3b are accommodated in the transfer unit 3.
Here, the transfer member 3a may be appropriately selected as long as it is a member capable of contact transfer such as a roll or a belt, and the cleaning member 3b includes various modes such as a brush and a blade.
Further, the unit holding mechanism 6 for holding the transfer unit 3 only needs to be movably held together with the unit case 3c, and is not limited to a mode of rotatably supporting.
Here, as a typical mode of the unit holding mechanism 6, the unit case 3 c is rotatably supported by the rotation support unit 5, and a portion separated from the rotation center of the unit case 3 c is raised and lowered by a lifting member, A unit that swings the unit case 3c about the center of rotation of the transfer member 3c so that the transfer member 3a can be moved toward and away from the image carrier 2 is exemplified.
The image forming engine 1 includes various aspects, and the image carrier 2 may be any type that can carry a visible image, and is not limited in form such as a belt shape and a drum shape. The number may be single or plural.

Further, in such an embodiment, the transfer unit 3 includes a cleaning residue storage section in the unit case 3c, and the unit case 3c has a partition section for separating the cleaning member disposition section and the cleaning residue storage section. Is preferably provided.
In this case, with the mode in which the transfer unit 3 comes and comes together with the unit case 3c, it is possible to avoid a situation in which the cleaning residue adheres again to the cleaning member 3b when the transfer unit 3 comes and goes.
The partition may be provided integrally with the unit case 3c or may be provided as a separate member.
Further, in the present embodiment, the transfer member 3a of the transfer unit is positioned while being rolled in contact with the positioning member 7 (indicated by a virtual line in the figure) during the setting process of being placed in contact with the image carrier 2, and It is preferable that the cleaning member 3b is disposed in a direction in which the rotational load is smaller than the rotational direction of the transfer member 3a that rolls in contact with the positioning member 7.
In this case, the load fluctuation of the transfer member 3a at the time of setting the transfer unit 3 can be suppressed, and the position reproducibility of the transfer member 3a due to the load fluctuation can be improved.

In particular, in a mode in which the image carrier 2 is provided with a cleaning member for cleaning, the transfer member 3a of the transfer unit 3 is positioned while being in contact with the positioning member 7 while being rolled in contact with the positioning member 7 in the setting process of being arranged in contact with the image carrier 2. The cleaning member 3b of the transfer unit 3 is arranged in a direction in which the rotation load is smaller than the rotation direction of the transfer member 3a that rolls in contact with the positioning member 7, and the cleaning member (not shown) of the image carrier 2 is It is preferable that the positioning member 7 be disposed in a direction in which the rotational load is small relative to the rotation direction of the image carrier 2 that rotates in contact with the transfer member 3a that contacts and rolls.
In this case, in a mode in which the cleaning member of the image carrier 2 is provided, the load fluctuation of the transfer member 3a when the transfer unit 3 is set can be suppressed, and the reproducibility of the position of the transfer member 3a due to the load fluctuation can be improved.

The second mode is to improve the change of the transfer condition. As shown in FIG. 1B, an image forming engine 1 including an image carrier 2 for carrying a visible image, and an image carrier 1 And a transfer member 3a for pressing the surface of the image carrier 2 through a recording material and transferring the visible image on the image carrier 2 onto the recording material at once. And the rotation supporting unit 5 supported by the unit. The transfer member 3a is incorporated in one unit case 3c, and the transfer supporting unit 3 is united with the rotation supporting unit 5 so that the transfer member 3a can be moved toward and away from the image carrier 2. A transfer unit 3 movably held with the case 3c; a unit holding mechanism 6 for holding the transfer unit 3 rotatably supports the unit case 3c on the rotation support unit 5; Rotation support of case 3c A set force F is applied to a portion distant from 3d, a reaction force R from the rotation fulcrum 3d of the unit case 3c is set in the direction of the rotation fulcrum 5d of the rotation support unit 5, and the reaction force of the set force F The moment M around the rotation fulcrum 5d of the rotation support unit 5 due to the force is set in a direction to rotate the rotation support unit 5 toward the apparatus main body 4.
Note that the transfer unit 3 of this embodiment only needs to include at least the transfer member 3a in the unit case 3c, and it is not essential to include the cleaning member 3b.

Here, in the conventional mode in which the transfer unit is disposed on a rotation support unit such as a door unit, the transfer roll is pressed against the backup roll of the intermediate transfer belt. A reaction force inevitably acts on the area, and this reaction force acts in a direction to open the door unit, and there is a concern that the door unit may be slightly deformed in the opening direction.
Under such circumstances, there is a concern that the positioning accuracy of the transfer unit provided in the door unit may be affected, and the transfer conditions of the transfer roll may change, such as a change in the nip pressure of the transfer roll. There is.

On the other hand, according to this aspect (see FIG. 1B), the moment generated by the nip force of the transfer member 3a with respect to the rotation support unit 5 is canceled, so that the deformation of the rotation support unit 5 is suppressed. Good positional accuracy of the transfer member 3a can be maintained.
As described above, according to the second aspect, in the process of setting the transfer unit, the direction in which the nip load of the transfer member is received by the rotation fulcrum of the rotation support unit and the rotation support unit is rotated toward the apparatus main body. Since the moment is applied, the reproducibility of the position of the transfer member can be ensured even when the rigidity of the rotation support unit is reduced.
For this reason, the transfer operation by the transfer member can be always performed satisfactorily, defects (jam, etc.) can be effectively prevented in the change of the peeling posture of the recording material, and the image quality of a color image or the like is always kept good. be able to.

  In addition, as shown in FIG. 1B, a modified embodiment of the second embodiment includes an image forming engine 1 including an image carrier 2 that carries a visible image, and a recording material on the surface side of the image carrier 2. And a transfer member 3a for transferring the visible image on the image carrier 2 onto the recording material at a time. The unit 5 and the transfer member 3a are assembled into one unit case 3c, and the unit case 3c is movably held with respect to the rotation support unit 5 so that the transfer member 3a can be moved toward and away from the image carrier 2. And a unit holding mechanism 6 for holding the transfer unit 3 rotatably supports the unit case 3c on the rotation support unit 6, and in the process of setting the transfer unit 3, the rotation fulcrum 3d of the unit case 3c. In a location away from And a moment around a pivot 5d '(shown by a dotted line in FIG. 1B) of the pivot support unit 5 due to a reaction force R from the pivot 3d of the unit case 3c. The sum M ′ of the moment around the rotation fulcrum 5d ′ of the rotation support unit 5 due to the reaction force of the force F is the direction in which the rotation support unit 5 is rotated toward the apparatus main body 4 or approximately zero. It is characterized by being.

In this case, the moment about the rotation fulcrum 5d 'of the rotation support unit 5 due to the reaction force from the rotation fulcrum 3d of the unit case 3c is usually the rotation fulcrum of the rotation support unit 5 due to the reaction force of the set force F. This is opposite to the moment around 5d ', which is preferable in that the moment acting on the rotation support unit 5 can be reduced.
For this reason, even if the rigidity of the rotation support unit 5 is reduced, it is possible to suppress the deformation of the rotation support unit 5.
In particular, it is preferable to set the total moment of both to substantially zero in that the deformation of the rotation support unit 5 is almost completely prevented.
As described above, according to the modification of the second aspect, the nip load or the like of the transfer member is received in the vicinity of the rotation fulcrum of the rotation support unit, and further, the rotation support unit is rotated in the direction of rotating toward the apparatus main body. If a moment is given or the moment is made substantially zero, the reproducibility of the position of the transfer member can be kept good while reducing the rigidity of the rotating support unit.

Further, the third aspect is to improve the reduction in maintenance workability, and as shown in FIG. 1C, an image forming engine 1 including an image carrier 2 for carrying a visible image, A transfer member 3a that is pressed against the surface of the body 2 via a recording material and collectively transfers the visible image on the image carrier 2 to the recording material; A freely supported pivoting support unit 5 and the pivoting support unit 5 in which the transfer member 3a is incorporated into one unit case 3c and the transfer member 3a can be moved toward and away from the image carrier 2. A transfer unit 3 movably held together with the unit case 3c so that maintenance parts (for example, the image carrier 2) of the image forming engine 1 can be replaced while the transfer unit 3 is arranged at the set position. Image engine 1 In which is disposed movably Tenansupatsu.
Note that the transfer unit 3 of this embodiment only needs to include at least the transfer member 3a in the unit case 3c, and it is not essential to include the cleaning member 3b.

Here, in the conventional mode, when the intermediate transfer unit is replaced, if the intermediate transfer unit is removed and inserted while the transfer roll is nipped, the intermediate transfer belt moves while sliding on the transfer roll. There is a concern that the intermediate transfer belt may be damaged. Therefore, when replacing the intermediate transfer unit, a method has been adopted in which the door unit is opened and the transfer unit is separated from the intermediate transfer unit.
When replacing the photoconductor unit for image formation, the photoconductor drum and the intermediate transfer belt must be separated to prevent damage to the photoconductor drum. Since the transfer unit could not be immediately inserted and removed, there was a restriction on maintenance work in that the photosensitive member unit had to be separated from the intermediate transfer unit and replaced.
As described above, in the mode in which the transfer unit is provided in the rotation support unit, there is a point that the maintenance workability is still insufficient.

On the other hand, according to the present embodiment (see FIG. 1C), while the transfer unit 3 is set at the set position, the maintenance part of the image forming engine 1, for example, the belt unit as the image carrier 2 is, for example, a one-dot chain line. Can be replaced by moving in the direction of the arrow shown by the arrow, the workability of replacing the maintenance parts of the imaging engine 1 can be improved.
As described above, according to the third aspect, since the maintenance parts of the image forming engine are movably disposed while the transfer unit is disposed at the set position, the maintenance work is performed in comparison with the maintenance work involving the movement of the transfer unit. Performance can be improved.

  According to the present invention, a rotation support unit rotatably provided on a side portion of an image forming apparatus main body and capable of opening and closing with respect to the image forming apparatus main body while holding a transfer unit, and a side of the image forming apparatus main body The transfer unit can be separated from the image carrier by rotating the rotating support unit, since the transfer unit is provided with a door that is openably and closably provided in the unit and the storage case can be first taken out when opened. The maintenance of the unit and transfer unit can be easily performed, and by opening the door, the storage case can be taken out first, so that the storage case can be removed without contaminating the inside of the image forming apparatus main body. Maintenance work can be performed.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. Embodiments 1 and 2 show a transfer unit mounting structure applicable to the present invention.
◎ Embodiment 1
FIG. 2 is an explanatory diagram showing Embodiment 1 of the tandem type image forming apparatus to which the present invention is applied.
In FIG. 1, a tandem type image forming apparatus includes an image forming unit 22 (specifically, black, yellow, magenta, and cyan in the present embodiment) in a main body housing (corresponding to the main body of the image forming apparatus) 21. Are arranged in a horizontal direction, and a belt unit (belt conveying device) 23 including an intermediate transfer belt 230 circulated and conveyed along the arrangement direction of the image forming units 22 is disposed above the belt unit (belt conveying device) 23. On the other hand, below the main body housing 21, a recording material supply cassette (not shown) for accommodating a recording material (not shown) such as paper is provided, and a conveying path of the recording material from the recording material supply cassette is provided. The recording material transport path is vertically arranged.

In this embodiment, the image forming units 22 (22a to 22d) are arranged in order from the upstream side in the circulation direction of the intermediate transfer belt 230, for example, for black, yellow, magenta, and cyan (the arrangement is not necessarily this order). (Not limited), and is provided with each photoconductor unit 30, each developing unit 33, and one common exposure unit 40.
Here, the photoconductor unit 30 includes, for example, a photoconductor drum 31, a charger (a charging roll in this example) 32 for pre-charging the photoconductor drum 31, and a cleaner 34 for removing residual toner on the photoconductor drum 31. Are integrated into a cartridge.
The developing unit 33 develops the electrostatic latent image formed by exposure on the charged photosensitive drum 31 by the exposure unit 40 with a corresponding color toner (for example, negative polarity in the present embodiment). is there.
On the other hand, the exposure unit 40 includes, for example, four semiconductor lasers (not shown), one polygon mirror (not shown), an imaging lens (not shown), and each of the photoconductor units 30 in a unit case. A mirror (not shown) is stored, light from a semiconductor laser for each color component is deflected and scanned by a polygon mirror, and a light image is guided to an exposure point on a corresponding photosensitive drum 31 via an imaging lens and a mirror. It is like that.

In the present embodiment, the belt unit 23 has an intermediate transfer belt 230 stretched between a plurality of stretching rolls 231 to 236, and an intermediate transfer belt corresponding to the photosensitive drum 31 of each photosensitive unit 30. A primary transfer device (primary transfer roll in this example) 51 is provided on the back surface of the belt 230, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer device 51, thereby causing The toner image is electrostatically transferred to the intermediate transfer belt 230 side.
Here, the intermediate transfer belt 230 is made of a resin such as polyimide, polycarbonate, polyester, or polypropylene or various rubbers containing an appropriate amount of an antistatic agent such as carbon black, and has a volume resistivity of 10 ⁶ to 10 ¹⁴ Ω. Cm, and the thickness is set to, for example, about 0.1 mm.
On the other hand, the tension roll 231 is a steering drive roll that tilts to control meandering in a lateral direction perpendicular to the running direction of the intermediate transfer belt 230 and that drives the intermediate transfer belt 230. Reference numerals 232 and 233 denote exposing rolls (both driven rolls) for exposing the primary transfer surface of the intermediate transfer belt 230 to the image forming units 22 (22a to 22d) at predetermined positions. Reference numeral 234 denotes a tension roll that is pressed against the intermediate transfer belt 230 with a predetermined tension by a biasing spring (not shown) to adjust the deflection of the intermediate transfer belt 230. Further, a tension roll 235 is a secondary transfer described later. This is a recording material posture adjustment roll for regulating the posture of the recording material entering the transfer nip area of the unit 52. 236 is a roll (driven roll) which also serves as a backup roll below secondary transfer unit 52.

Further, a secondary transfer unit 52 is provided at a position corresponding to the tension roll 236 on the downstream side of the most downstream image forming unit 22d of the intermediate transfer belt 230, and records a primary transfer image on the intermediate transfer belt 230. Secondary transfer (collective transfer) is performed on the material.
In the present embodiment, in the secondary transfer unit 52, a secondary transfer roll 522 is provided in the opening of the unit case 521, and this secondary transfer roll is used as a backup roll (in this example, the tension roll 236 is also used). For example, the secondary transfer roll 522 is grounded, and a bias having the same polarity as the charged polarity of the toner is applied to the backup roll (stretch roll 236).
Here, the secondary transfer roll 522 is made of a urethane rubber tube in which carbon is dispersed on the surface, and the inside is made of foamed urethane rubber in which carbon is dispersed. Further, the roll surface is coated with fluorine, and its volume resistivity is 10 ³ to 10 ¹⁰ The roll is formed to have a roll diameter of, for example, φ28 mm in Ω · cm, and the hardness is set to, for example, 30 ° (Asuka C).
The backup roll 236 is provided with a tube of EPDM and NBR blended rubber in which carbon is dispersed on the surface, and the inside thereof is formed of EPDM rubber, and has a surface resistivity of 10 ⁷ to 10 ¹⁰ Ω / □. And the roll diameter is set to, for example, φ28 mm, and the hardness is set to, for example, 70 ° (Asuka C).
In particular, in the present embodiment, the secondary transfer unit 52 includes a cleaning brush 523 in the unit case 521 for cleaning the surface of the secondary transfer roll 522.
The mounting structure and drive system of the secondary transfer unit 52 will be described later.

Further, a belt cleaner 53 is disposed upstream of the intermediate transfer belt 230 from the uppermost stream image forming unit 22a so as to remove residual toner on the intermediate transfer belt 230.
A feed roll (not shown) for picking up the recording material is provided in a recording material supply cassette (not shown). Immediately after this feed roll, a takeaway roll for sending out the recording material is provided. An appropriate number of transport rolls 61 are disposed in the material transport path, and a registration roll that supplies the recording material to the secondary transfer site at a predetermined timing is provided in the recording material transport path located immediately before the secondary transfer site. (Resist roll) 62 is provided.
On the other hand, a fixing device 66 is provided in a recording material conveyance path located downstream of the secondary transfer portion, and a discharge roll (not shown) for discharging the recording material is provided downstream of the fixing device 66. The recording material is accommodated in an accommodation tray 68 formed at an upper portion of the main body housing 21.

Next, the mounting structure of the secondary transfer unit 52 will be described.
In this embodiment, as shown in FIGS. 2 to 4, a door unit 70 is supported on the side of the main body housing 21 so as to be openable and closable about a pivot point 71. , A secondary transfer unit 52 is attached via a retract mechanism 80.
Here, the secondary transfer unit 52 has a rotation fulcrum (configured as a pin in this embodiment) 524 on both sides of the unit case 521, and a bracket 73 attached to the frame 72 of the door unit 70 (a virtual line in FIG. 4). 4), a long hole 74 (shown by an imaginary line in FIG. 4) is formed, and the rotation fulcrum 524 is locked in the long hole 74 to be rotatably supported.

  In the present embodiment, the retract mechanism 80 is provided with an eccentric cam 81 which is rotated by a lifting motor (not shown), as shown in FIGS. 4 and 5, and a slide lever 82 is provided above the eccentric cam 81. Is held by a guide roller 83 (see FIG. 6) so as to be able to move up and down. A bent portion 82a facing the surface of the eccentric cam 81 is formed at the lower end of the slide lever 82, and the tip of the lower bent portion 82a is attached. While being biased downward by a biasing spring 84, a bent portion 82b is formed at the upper end of the slide lever 82 so as to be inclined obliquely downward from the horizontal direction, and the upper bent portion 82b and the secondary transfer unit are formed. The unit 52 is connected and fixed to a portion (in this example, an upper portion of the unit case 521) of the unit case 521 separated from the pivot 524 by a connecting rod 85.

On the other hand, on the belt unit 23 side, as shown in FIGS. 2 to 4, a positioning plate 90 (indicated by a virtual line in the figure) for positioning the secondary transfer roll 522 at the set position is provided. A V-shaped positioning groove 91 for positioning the secondary transfer roll 522 is formed in the positioning plate 90, and the edge of the positioning groove 91 is brought into contact with the support shaft of the two-character transfer roll 522. The secondary transfer roll 522 is positioned in the positioning groove 91 by being guided and moved to the back of the positioning groove 91 (corresponding to the set position).
2 to 4, reference numeral 63 denotes a transfer chute provided on the downstream side of the registration roll 62. When the door unit 70 is opened, one transfer chute is opened together with the one registration roll 62 together with the door unit 70. Reference numerals 64 and 65 denote conveyance guides provided downstream of the secondary transfer portion to guide and convey the recording material toward the fixing device 66. In this example, the conveyance guides will be opened together with the door unit 70. It has become.

6 and 7 show a drive system 100 of the secondary transfer unit 52 used in the present embodiment.
In the figure, a drive system 100 of the secondary transfer unit 52 has a drive motor 101 fixedly disposed on a main body housing 21 (see FIG. 2), and a drive transmission gear 102 is coaxially fixed to a drive shaft of the drive motor 101. On the other hand, the driven transmission gear 103 is coaxially fixed to one end of the secondary transfer roll 522, and the secondary transfer roll 522 is set at the set position (see FIG. 7A) or the retract position (FIG. 7B). (See FIG. 3), the drive transmission gear 102 and the driven transmission gear 103 are engaged with each other.
7A and 7B, the same components as those in FIGS. 2 to 5 are denoted by the same reference numerals, and the detailed description thereof will be omitted.

Next, an image forming process of the image forming apparatus according to the present embodiment will be described.
Each of the image forming units 22 (22a to 22d) forms each color component image (toner image) on the photosensitive drum 31 and sequentially primary-transfers each color component image onto the intermediate transfer belt 230 by the primary transfer device 51.
On the other hand, a recording material is supplied from a recording material supply cassette (not shown), and is conveyed to a secondary transfer portion at a predetermined timing via a registration roll 62.
Then, the multi-transferred image primarily transferred onto the intermediate transfer belt 230 is conveyed to a secondary transfer portion, and is collectively transferred to a recording material by the secondary transfer unit 52.
Thereafter, the recording material is fixed to the image transferred collectively via the fixing device 66, and then discharged to the storage tray 68 through a discharge roll (not shown).
In each image forming unit 22, the residual toner on the photosensitive drum 31 is cleaned by the cleaner 34, while the residual toner on the intermediate transfer belt 230 is cleaned by the belt cleaner 53.

In such an image forming process, the secondary transfer unit 52 moves the secondary transfer roll 522 from the retracted position (see FIG. 5B) to the set position (see FIG. 5A) immediately before performing the secondary transfer operation. And retracts from the set position to the retract position when the secondary transfer operation is completed or when the power is turned off.
Here, the operation state of the retract mechanism 80 when the secondary transfer roll 522 is located at the set position will be described. In the retract mechanism 80, the eccentric cam 81 has the lowest cam surface (see FIG. 5A). It is in.
At this time, the lower bent portion 82 a of the slide lever 82 is not in contact with the cam surface of the eccentric cam 81, and the slide lever 82 is pushed down by the biasing spring 84.
Then, the unit case 521 rotates in the direction of the arrow around the rotation fulcrum 524, and the secondary transfer roll 522 in the unit case 521 approaches the backup roll 236 side, and moves to the positioning groove 91 of the positioning plate 90. It is engaged and positioned.

On the other hand, the operation state of the retract mechanism 80 when the secondary transfer roll 522 is located at the retract position will be described. In the retract mechanism 80, the cam surface of the eccentric cam 81 is at the highest position (see FIG. 5B). is there.
At this time, the lower bent portion 82 a of the slide lever 82 is pushed up by the eccentric cam 81, and the slide lever 82 is pushed upward against the urging force of the urging spring 84.
Then, the unit case 521 rotates around the rotation fulcrum 524, and the secondary transfer roll 522 in the unit case 521 moves in a direction away from the backup roll 236, and reaches a retract position separated from the set position. .

Further, in this example, the retract mechanism 80 includes a delay circuit that operates when the power is turned off, and makes it possible to move the secondary transfer roll 522 to the retract position when the power is turned off.
For this reason, in the present embodiment, when the power is turned off, the retract mechanism 80 operates to always set the secondary transfer roll 522 to the retract position. Therefore, when the power is turned on, the secondary transfer unit 52 starts operating from a state where the secondary transfer roll 522 is held at the retract position.

Further, in the present embodiment, as shown in FIG. 7B, the drive system 100 of the secondary transfer unit 52 drives the drive motor 101 even when the secondary transfer roll 522 is located at the retract position. Since the connected drive transmission gear 102 and driven transmission gear 103 are engaged, the secondary transfer roll 522 is immediately driven and rotated.
For this reason, when the secondary transfer roll 522 is moved from the retract position (see FIG. 7B) to the set position (see FIG. 7A), the secondary transfer roll 522 is set to the set position while rotating. can do.
Therefore, even if the intermediate transfer belt 230 is rotated in advance before the secondary transfer roll 522 reaches the set position and the image forming process of each image forming unit 22 is started, the secondary transfer roll 522 reaches the set position. Then, at the moment when the intermediate transfer belt 230 comes into contact with the intermediate transfer belt 230, the speed of the intermediate transfer belt 230 fluctuates, and there is no adverse effect on the image displacement or the motion quality of the intermediate transfer belt 230.

Further, in the present embodiment, the position of the drive transmission gear 102 is uniquely determined from the positional relationship with the drive motor 101, but the position of the driven transmission gear 103 is determined by the position change of the secondary transfer roll 522. It moves with it.
For this reason, in the present embodiment, when the secondary transfer roll 522 is at the set position (see FIG. 7A), the drive transmission gear 102 and the driven transmission gear 103 mesh with each other at the regular position, and A stable rotation drive is given to the transfer roll 522.
However, when the secondary transfer roll 522 is located at the retract position (see FIG. 7B), the meshing state of the two gears 102 and 103 deviates from the normal position, but the tooth radius of the gears 102 and 103 is smaller. If the distance between the centers of both gears 102 and 103 is set to be less than the sum, the meshing state of both gears 102 and 103 is maintained.

Further, in the present embodiment, when a recording material jam occurs during the transfer operation by the secondary transfer unit 52, the door unit 70 is opened as shown in FIGS. Can be used for jam processing.
In this case, the secondary transfer unit 52 is opened together with the door unit 70. The secondary transfer unit 52 is one in which the secondary transfer roll 522 and the cleaning brush 523 are incorporated in the unit case 521, and the retract mechanism 80 As a result, the secondary transfer unit 52 moves along with the unit case, so that the opening of the unit case 521 may be secured by a dimension corresponding to the secondary transfer roll 522, and the unit case 521 and the secondary transfer roll 522 There is no unnecessary gap between them.
Therefore, even if the secondary transfer unit 52 rotates together with the door unit 70, there is no possibility that the toner cloud is unnecessarily blown out from the opening of the unit case 521.

Further, in the present embodiment, the drive system 100 of the secondary transfer unit 52 fixes the driven transmission gear 103 coaxially with the secondary transfer roll 522, but is not limited to this. Instead, for example, a drive system 100 as shown in FIGS. 8A and 8B may be adopted.
In the drive system 100 of the secondary transfer unit 52 shown in the figure, a drive motor 111 is fixedly arranged on the main body housing 21 (see FIG. 2), and a drive transmission gear 112 is coaxially fixed to a drive shaft of the drive motor 111. The driven transmission gear 113 is coaxially fixed to the rotation fulcrum 524 of the unit case 521 of the secondary transfer unit 52, and the driven transmission gear 113 is coaxially fixed to the secondary transfer roll 522. The drive transmission gear 112 is engaged in any state in which the gear 113 is engaged and the secondary transfer roll 522 is located at the set position (see FIG. 8A) or the retract position (see FIG. 8B). And the driven transmission gear 113 are meshed with each other.

Here, the unit case 521 is rotated around the rotation fulcrum 524 by the retract mechanism 80, and the rotation fulcrum 524 engages with the bracket 73 of the door unit 70 engaged with the elongated hole 74. Since the mechanism is a mechanism, the position of the rotation fulcrum 524, which is the center of rotation of the link mechanism, does not vary much.
For this reason, in this example, the driven transmission gear 113 is fixed to the rotation fulcrum 524 of the unit case 521 with little position fluctuation, and it is possible to maintain the meshing state with the drive transmission gear 112 at each position. It is.
Also in this example, when the secondary transfer roll 522 is located at the set position (see FIG. 8A), the drive transmission gear 112 and the driven transmission gear 113 mesh with each other at the regular position, and the secondary transfer roll 522 is engaged. Is provided with a stable rotational drive.
However, when the secondary transfer roll 522 is located at the retract position (see FIG. 8B), the meshing state of the gears 112 and 113 is shifted from the normal position, but the tooth radius of the gears 112 and 113 is smaller. If the distance between the centers of both gears 112 and 113 is set to be less than the sum, the meshing state of both gears 112 and 113 is maintained.

Further, in the present embodiment, toner residue by the cleaning brush 523 accumulates in the unit case 521 of the secondary transfer unit 52.
At this time, as shown in FIG. 9, when the residual toner accumulation unit 120 is secured in the lower area of the unit case 521, particularly when the door unit 70 is opened and closed, the secondary transfer unit 52 is largely rotated and moved. The toner accumulated in the accumulation unit 120 flows back to the cleaning brush 523 and adheres again, which may cause the secondary transfer roll 522 to be stained.
For this reason, in the present embodiment, it is preferable to provide the partition 121 between the arrangement part of the cleaning brush 523 and the residual toner accumulation part 120 in the unit case 521.
Here, as the partition part 121, as shown in FIG. 9, a partition wall protruding inward may be provided in a part of the unit case 521, or a separate member may be provided in the unit case 521. A wall may be provided.
In FIG. 9, reference numeral 122 denotes an elastic seal lip attached to the lower edge of the opening of the unit case 521 to keep the space between the secondary transfer roll 522 airtight.

Further, in the present embodiment, the direction of the brush body 523a of the cleaning brush 523 is also devised.
That is, in the present embodiment, as shown in FIG. 10A, the door unit 70, the secondary transfer unit 52, and the belt unit 23 are provided, and the driving system of the cleaning brush 523 in the secondary transfer unit 52 is provided. As shown in FIG. 10B, a drive transmission gear 131 is provided at one end of a secondary transfer roll 522, while a driven transmission meshing with the drive transmission gear 131 is provided at one end of a rotation shaft of the cleaning brush 523. A gear 132 is provided, and the cleaning brush 523 is driven to rotate following the secondary transfer roll 522.
In such an embodiment, during the setting process, the secondary transfer roll 522 causes the support shaft to abut on the edge of the V-shaped positioning groove 91 of the positioning plate 90, and the support shaft is contact-rolled by the edge. The secondary transfer roll 522 is positioned while being moved, but the rotation direction at the time of positioning the secondary transfer roll 522 differs depending on which edge of the positioning groove 91 is located.

For example, as shown in FIG. 11A, in a mode in which the support shaft portion 522a of the secondary transfer roll 522 abuts on the upper edge portion 91a of the positioning groove 91 and rolls downwardly in contact with the secondary transfer roller 522. The roll 522 rotates counterclockwise as indicated by the arrow, and the cleaning brush 523 rotates clockwise in reverse.
On the other hand, for example, as shown in FIG. 11B, in a mode in which the support shaft portion 522a of the secondary transfer roll 522 comes into contact with the lower edge portion 91b of the positioning groove 91 and rolls upward in contact therewith. The secondary transfer roll 522 rotates clockwise as indicated by the arrow, and the cleaning brush 523 rotates counterclockwise.
At this time, in the present embodiment, the brush body 523a of the cleaning brush 523 is arranged in a direction in which the rotation load is smaller than the rotation direction of the secondary transfer roll 522, as shown in FIG.
Note that, in a mode in which the cleaning blade 525 is used instead of the cleaning brush 523, as shown in FIG. 11D, the cleaning is performed so that the rotation load is smaller in the rotation direction of the secondary transfer roll 522. What is necessary is just to arrange the blade 525.
Therefore, the load fluctuation of the secondary transfer roll 522 at the time of setting the secondary transfer unit 52 is suppressed, and the position reproducibility of the secondary transfer roll 522 due to the load fluctuation is kept good.

Particularly, in the present embodiment, the belt cleaner 53 on the side of the belt unit 23 includes the cleaning blade 53a in the direction shown in FIG.
Since the cleaning blade 53a is arranged in a direction in which the rotational load is reduced when the intermediate transfer belt 230 rotates in the direction of the arrow, from the viewpoint of suppressing the influence of the rotational load by the cleaning blade 53a, In the positioning process of 522, the intermediate transfer belt 230 may be rotated in the above-described direction.
In this example, specifically, as shown in FIG. 11B, for example, the support shaft portion 522a of the secondary transfer roll 522 is brought into contact with the lower edge portion 91b of the positioning groove 91 of the positioning plate 90, If the method of rotating the secondary transfer roll 522 in the direction of the arrow at the time of positioning is adopted, when the secondary transfer roll 522 comes into contact with the intermediate transfer belt 230, the intermediate transfer belt 230 is moved in the direction of the arrow shown in FIG. This makes it possible to rotate the secondary transfer roll 522, whereby the rotation load on the secondary transfer roll 522 can be further reduced in the process of positioning the secondary transfer roll 522.
Therefore, the load fluctuation of the secondary transfer roll 522 at the time of setting the secondary transfer unit 52 is further reduced, and the reproducibility of the position of the secondary transfer roll 522 due to the load fluctuation is kept good.

◎ Embodiment 2
FIG. 12 is an explanatory diagram illustrating a main part of the image forming apparatus according to the second embodiment.
In the figure, the image forming apparatus according to the present embodiment has a basic configuration substantially similar to that of the first embodiment, and further sets a new force relationship acting on the door unit 70. Note that components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted.
That is, in the present embodiment, as shown in FIG. 12, the unit case 521 of the secondary transfer unit 52 is rotatably supported by the door unit 70, and the unit case 521 is turned in the process of setting the secondary transfer unit. Although the set force F is applied to a portion away from the fulcrum 524, the reaction force R from the fulcrum 524 of the unit case 521 is set in the direction of the fulcrum 71 of the door unit 70, and The moment M around the rotation fulcrum 71 of the door unit 70 due to the reaction force of the set force F is set in a direction to rotate the door unit 70 toward the main body housing 21 (see FIG. 2).

Here, as a method of setting the reaction force R from the rotation fulcrum 524 of the unit case 521 toward the rotation fulcrum 71 of the door unit 70, the longitudinal direction of the long hole 74 of the bracket 73 is set to the rotation fulcrum of the door unit 70. What is necessary is just to set in the tangential direction of the circular locus m of the radius which connects 71 and the rotation fulcrum 524 of the unit case 521.
In this example, when the secondary transfer unit 52 is set, the force acting on the secondary transfer unit 52 is, as shown in FIG. 13, the set force F from the retract mechanism 80 and the reaction force R acting on the pivot 524. And the force K applied to the secondary transfer roll 522 side. If all the forces are now set to be substantially parallel, the forces F, R, and K are in a balanced relationship of F + R + K = 0. It is in.
In this state, considering the moment M around the door unit 70, the external forces acting on the door unit 70 are F and R, and R is directed toward the rotation fulcrum 71 of the door unit 70. If the moment span up to the point of application of the set force F to the rotation fulcrum 71 is r, then M = F · r.

According to this aspect, the reaction force R acting on the rotation fulcrum 524 receives a nip load or the like from the secondary transfer roll 522, and this reaction force R is received by the rotation fulcrum 71 of the door unit 70.
Therefore, the door unit 70 is not unnecessarily distorted and deformed by the reaction force R.
Further, since a moment M that rotates toward the main body housing 21 acts on the door unit 70, there is no concern that the door unit 70 will be displaced in the opening direction.
Therefore, even if a reaction force R corresponding to the nip force (7 to 10 kgf) of the secondary transfer roll 522 is generated, the reaction force R is received by the rotation fulcrum 71 of the door unit 70, so that This eliminates the need for a rigid structure capable of withstanding a nip force of about 10 kgf.
Further, since a moment M in the closing direction acts on the door unit 70, the positioning accuracy of the secondary transfer roll 522 is kept good, and the position reproducibility of the secondary transfer roll 522 is ensured.

In a modification of the present embodiment, as shown in FIG. 14, the reaction force R (the nip load of the secondary transfer roll 522 and the positioning plate) from the rotation fulcrum 524 of the unit case 521 of the secondary transfer unit 52 is provided. The moment M1 around the pivot fulcrum 71 of the door unit 70 (R · r1 if the moment span from the pivot fulcrum 71 is r1) due to the reaction force load from the positioning groove 91 at 90, and the set force F The sum of the moment M2 around the pivot fulcrum 71 of the door unit 70 due to the action reaction force (F · r2 if the moment span from the pivot fulcrum 71 is r2) turns the door unit 70 toward the body housing 21 side. Orientation may be used.
In this embodiment, if the nip load or the like of the secondary transfer roll 522 is received in the vicinity of the pivot fulcrum 71 of the door unit 70, the secondary transfer roll can be formed without increasing the rigidity of the door unit 70 so much. The door unit 70 is not distorted and deformed by the nip load of 522 or the like.

Further, since the sum of the moments acts in the direction to close the door unit 70, the reproducibility of the position of the secondary transfer roll 522 is also ensured.
In particular, in the present embodiment, since the moment M1 is a component acting in the direction in which the door unit 70 opens, the total moment itself is suppressed to be smaller than that in the embodiment.
Therefore, distortion deformation due to the moment acting on the door unit 70 is reduced.
In this modification, the sum of the moments may be set to substantially zero. In this case, no moment acts on the door unit 70 in the closing direction. It can be rigid.

◎ Embodiment 3
FIG. 15 is an explanatory diagram illustrating the image forming apparatus according to the third embodiment.
In the figure, the image forming apparatus according to the present embodiment has a configuration substantially similar to that of the first embodiment, and further improves maintenance workability.
Note that components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted.
In this example, the belt unit 23 has a belt unit support mechanism 600. The belt unit support mechanism raises and lowers the belt unit 23 by rotating the operation arm 601, and guide rails at the raised position. The belt unit 23 can be inserted and removed along the line 602.
The photoconductor unit 30 has a photoconductor unit support mechanism (not shown) that can be pulled out from the front side of the main body housing.

First, when replacing the secondary transfer unit 52, the secondary transfer unit 52 is removed by opening the door unit 70, as shown in FIGS. 16 and 20A and 20B. After the new secondary transfer unit 52 is set as the door unit 70 while the door 70 is open, the door unit 70 may be closed.
At this time, as shown in FIG. 20A, when the door unit 70 is opened, the support shaft 522a of the secondary transfer roll 522 is guided upward along the positioning groove 91 of the positioning plate 90, and conversely. When the door unit 70 is closed, the support shaft 522 a of the secondary transfer roll 522 is guided downward along the positioning groove 91 of the positioning plate 90.

When the belt unit 23 is replaced, the secondary transfer unit 52 may be kept at the set position. First, as shown in FIG. 17, the operation arm 601 of the belt unit support mechanism 600 is pushed down to the near side. Thereby, the belt unit 23 is pushed upward.
At this time, as shown in FIG. 21, as the belt unit 23 rises, the support shaft portion 522a of the secondary transfer roll 522 separates from the positioning groove 91 of the positioning plate 90, and the belt unit 23 Is separated from the photosensitive drum 31.
In this state, as shown in FIGS. 18 and 21, after opening the corresponding side door 610 of the main body housing 21, the belt unit 23 may be pulled out along the guide rail 602 of the belt unit support mechanism 600. .

When the belt unit 23 is mounted after the replacement, the reverse procedure of the above-described removal process may be performed.
At this time, when the operation arm 601 is raised and lowered after the belt unit 23 is inserted into the main body housing 21, the positioning groove 91 of the positioning plate 90 is moved to the secondary position when the belt unit 23 is lowered. Engage with the secondary transfer roll 522 of the transfer unit 52.
When the belt cleaner 53 of the belt unit 23 is replaced, the belt cleaner 53 is replaced when the belt cleaner 53 is exposed outside the main body housing 21 while the belt unit 23 is replaced. What should I do?

Further, when the photoconductor unit 30 is replaced, as shown in FIG. 19, after the belt unit 23 is raised, the front door 611 of the main body housing 21 is opened, and the photoconductor unit 30 may be pulled out. .
When the photoconductor unit 30 is mounted, a new photoconductor unit 30 may be inserted into the main body housing 21 and then the belt unit 23 at the raised position may be lowered.
At this time, as shown in FIG. 22, since only the belt unit 23 is raised and lowered, the secondary transfer unit 52 can be left at the set position.

FIGS. 3A to 3C are explanatory views showing preferred embodiments of the image forming apparatus according to the present invention. FIG. 1 is an explanatory diagram illustrating an overall configuration of an image forming apparatus according to a first embodiment. FIG. 3A is an explanatory diagram illustrating a state in which the door unit is closed in the image forming apparatus according to the present embodiment, and FIG. 3B is an explanatory diagram illustrating a state in which the door unit is opened in the image forming apparatus. FIG. 3 is an explanatory diagram illustrating details of a secondary transfer unit used in the embodiment. (A) is an explanatory view showing the state of the secondary transfer unit when the secondary transfer roll is located at the set position, and (b) is the state of the secondary transfer unit when the secondary transfer roll is located at the retract position. FIG. FIG. 3 is an explanatory diagram illustrating a drive system of a secondary transfer unit according to the embodiment. (A) is an explanatory view showing the state of the drive system when the secondary transfer roll is located at the set position, and (b) is an explanatory view showing the state of the drive system when the secondary transfer roll is located at the retract position. is there. FIG. 4A is a diagram illustrating a modified example of the drive system of the secondary transfer unit according to the present embodiment, in which FIG. FIG. 4 is an explanatory diagram illustrating a state of a drive system when a transfer roll is located at a retract position. FIG. 9 is an explanatory diagram illustrating a modified example of the secondary transfer unit according to the present embodiment. (A) is an explanatory view showing a layout of a door unit, a secondary transfer unit and a belt unit used in the present embodiment, and (b) is an explanatory view showing a drive system of a cleaning brush of the secondary transfer unit. (A) is an explanatory view showing an example of a state at the time of positioning the secondary transfer roll, (b) is an explanatory view showing another example of a state at the time of positioning the secondary transfer roll, and (c) is a brush of the cleaning brush FIG. 7D is an explanatory diagram illustrating the orientation of the body, and FIG. 9D is an explanatory diagram illustrating a layout example when a cleaning blade is used instead of the cleaning brush. FIG. 9 is an explanatory diagram illustrating a main part of an image forming apparatus used in a second embodiment. FIG. 13 is an explanatory diagram illustrating a state of balance of the force of the secondary transfer unit according to the second embodiment. FIG. 14 is an explanatory diagram showing an action state of a moment acting on a door unit in a modified example of the second embodiment. FIG. 13 is an explanatory diagram illustrating an outline of a usage state of the image forming apparatus used in the third embodiment. FIG. 19 is an explanatory diagram illustrating an example of a maintenance operation when exchanging the secondary transfer unit in the third embodiment. FIG. 19 is an explanatory diagram showing a first step of a maintenance work example when replacing a belt unit in the third embodiment. FIG. 19 is an explanatory diagram showing a second step of the example of the maintenance work when replacing the belt unit in the third embodiment. FIG. 13 is an explanatory diagram illustrating an example of a maintenance operation when exchanging a photoconductor unit in the third embodiment. (A) is an explanatory view showing a state around the secondary transfer unit in a maintenance work example when removing the secondary transfer unit, and (b) is a periphery of the secondary transfer unit in a maintenance work example when installing the secondary transfer unit. It is explanatory drawing which shows the state. FIG. 9 is an explanatory diagram illustrating a state around a secondary transfer unit in a maintenance operation example when a belt unit is replaced. FIG. 9 is an explanatory diagram illustrating a state around a secondary transfer unit in a maintenance operation example when exchanging a photoconductor unit. FIG. 3A is an explanatory diagram illustrating an example of an image forming apparatus in which a secondary transfer unit is provided in a conventional door unit, and FIG. 3B is an explanatory diagram illustrating a state in which the door unit is opened.

Explanation of reference numerals

  DESCRIPTION OF SYMBOLS 1 ... Image formation engine, 2 ... Image carrier, 3 ... Transfer unit, 3a ... Transfer member, 3b ... Cleaning member, 3c ... Unit case, 3d ... Rotating fulcrum, 4 ... Device main body, 5 ... Rotation support unit, 5d, 5d ': rotation fulcrum, 6: unit holding mechanism, 7: positioning member

Claims (5)

An image carrier that carries a visible image, a transfer unit that presses the surface of the image carrier through a recording material, and collectively transfers the visible image on the image carrier to the recording material; In an image forming apparatus having a storage case capable of storing a residual of a visible image,
A rotation support unit rotatably provided on the side of the image forming apparatus main body and capable of opening and closing with respect to the image forming apparatus main body while holding the transfer unit;
A door provided on the side of the image forming apparatus main body so as to be openable and closable, and the storage case can be taken out first when opened;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
An image forming apparatus, comprising: an image carrier including a plurality of photosensitive drums and a belt unit arranged to face the photosensitive drum, and a transfer unit arranged to face the belt unit. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the door is provided on the other side of the image forming apparatus main body opposite to the rotation support unit provided on one side of the image forming apparatus main body. The image forming apparatus according to claim 2,
An image forming apparatus, wherein the belt unit can be pulled out horizontally from the side of the image forming apparatus main body through an opening when the door is opened. The image forming apparatus according to claim 2,
The image forming apparatus is characterized in that the storage case collects a residual of a visible image on the belt unit.

Images