JP5768500B2 - Image forming apparatus - Google Patents

Description

The present invention is a copying machine having a recording medium conveying equipment for conveying while adsorbing the recording medium such as paper at a negative pressure, a printer, a facsimile, an image forming apparatus such as a plotter.

2. Description of the Related Art There is known a recording medium conveying apparatus that conveys a recording medium such as paper, and an image forming apparatus such as a copying machine, a printer, a facsimile, and a plotter having the recording medium (see, for example, [Patent Document 1]).
Such a recording medium conveying apparatus is often configured to be partially or entirely displaced for the purpose of facilitating jam processing (for example, [Patent Document 1] and [Patent Document 1]. 2]).

  On the other hand, there is known a recording medium conveying apparatus that conveys a recording medium while adsorbing it at a negative pressure for the purpose of improving the certainty of conveyance (for example, see [Patent Document 1] and [Patent Document 2]). . Such a recording medium conveying apparatus has a duct through which an air flow for forming a negative pressure is passed.

  In the recording medium conveying apparatus having such a duct and configured to be partially or entirely displaced as described above, the duct is configured to be divided by the displacement. There is. In the conventional recording medium transport apparatus having such a configuration, as a structure of the divided positions of the ducts, that is, the connected positions, the surfaces of the connected ducts that are in contact with each other are parallel to the displacement direction. (See, for example, [Patent Document 1] and [Patent Document 2]).

However, since the structure of the connecting position is configured to be in close contact with each other in order to prevent a negative pressure drop, in the displacement for connecting the divided ducts to each other, Rub each other. When such rubbing occurs, deterioration such as change in the shape of the coupling position occurs, and as a result, negative pressure decreases.
In order to prevent such rubbing, reducing the adhesion at the connection position causes a decrease in negative pressure.
Therefore, in a structure in which the surfaces of the connected ducts that are in contact with each other are parallel to the direction of displacement, avoiding both negative pressure drop and deterioration at the connecting position of the duct is a trade-off. It is related and difficult.

The present invention has a recording medium conveying equipment which achieve both a negative pressure drop and preventing deterioration prevention in coupling position of the duct to a recording medium conveying device for conveying while adsorbing the recording medium such as paper by negative pressure An object of the present invention is to provide an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a plotter.

In order to achieve the above object, the present invention provides a conveying member that carries and conveys a recording medium, and a first duct that passes an air flow for forming a negative pressure that adsorbs and carries the recording medium on the conveying member. A transport unit, and when the transport unit is in a transport position for transporting a recording medium by the transport member, the transport unit is connected to a first duct and receives the air flow from the first duct. And a second duct separated from the first duct when the unit is in a detached position where the unit is separated from the conveying position. The first duct and the second duct are respectively separated by the conveying unit. A first inclined surface and a second inclined surface which are inclined with respect to a moving direction moving from the position toward the conveying position and are connectable to each other, and the conveying unit is moved from the separating position to the conveying position. In Only it has a first inclined surface and the recording medium conveying device and the second inclined surface and the first duct and the second duct are connected by being bonded to each other when moving said recording medium The transport device is displaceable between a mounting position mounted in the main body and capable of transporting the recording medium by the transport member, and a pull-out position pulled out from the mounting position toward the outside of the main body. In the image forming apparatus in which the unit can be set to the separation position in a state where the recording medium conveyance device is in the pull-out position, the unit is provided in the second duct when the recording medium conveyance device is in the mounting position. A third duct that is coupled to receive the air flow from the second duct and that is separated from the second duct when the recording medium transport device is displaced from the mounting position toward the pulling position; In the image forming apparatus.

The present invention relates to a transport unit comprising a transport member that carries and transports a recording medium, and a first duct that passes an air flow for forming a negative pressure that causes the transport medium to adsorb and carry the recording medium. When the transport unit is at a transport position for transporting the recording medium by the transport member, the transport unit is connected to a first duct and receives the air flow from the first duct, and the transport unit is detached from the transport position. A second duct separated from the first duct when in the separated position, wherein the first duct and the second duct are each directed so that the transport unit moves from the detached position toward the transport position. A first inclined surface and a second inclined surface that are inclined with respect to the moving direction and can be joined to each other, and the transfer unit moves from the separation position toward the transfer position. First Includes an inclined surface and a first duct and a recording medium conveying equipment to the second duct are connected by a second inclined surfaces are joined together, the recording medium transport device, by the conveying member The recording medium can be transported between a mounting position mounted in the main body and a drawing position pulled out from the mounting position toward the outside of the main body. In the image forming apparatus that can be set to the detachment position in a state in which the recording medium is in the pull-out position, the second medium is connected to the second duct when the recording medium transport device is in the mounting position. receiving said air flow, there the image forming apparatus having a third duct which is separated from the second duct by the recording medium transport device is displaced toward the pull-out position from the mounting position The first inclined surface and the second inclined surface can be prevented from rubbing with each other when the transport unit moves from the disengagement position toward the transport position. Prevention of lowering of negative pressure for adsorbing and supporting the recording medium on the conveying member at the connection position of the duct and the second duct, and prevention of deterioration of the first duct and the second duct at the connection position it is possible to provide the images forming apparatus is Ru can both be achieved.

It is a schematic front view of an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a schematic front view illustrating a configuration around an image carrier and a recording medium conveyance device provided in the image forming apparatus illustrated in FIG. 1. FIG. 3 is a schematic plan view showing a part of the recording medium conveyance device shown in FIG. 2 and a configuration around it. FIG. 3 is a schematic perspective view of a part of the recording medium conveyance device shown in FIG. 2. FIG. 3 is a schematic front sectional view of a part of the recording medium conveyance device shown in FIG. 2. FIG. 3 is a schematic front view illustrating a state in which the recording medium conveying apparatus illustrated in FIG. 2 occupies a conveyance position. FIG. 3 is a schematic front view illustrating a state in which the recording medium conveyance device illustrated in FIG. 2 is located at a conveyance position and a separation position.

It shows a schematic of an image forming apparatus according to the present invention in FIG. The image forming apparatus 100 is a color digital multi-function peripheral that is capable of forming a full-color image, and is a multi-function peripheral of a copying machine, a printer, and a facsimile machine. Other copiers such as a copier, a printer, a facsimile alone, or a copier and printer may be used. When used as a printer, the image forming apparatus 100 performs an image forming process based on an image signal corresponding to image information received from the outside. This is the same when the image forming apparatus 100 is used as a facsimile.

  The image forming apparatus 100 forms an image on a sheet-like recording medium that is a recording sheet, in addition to plain paper generally used for copying or the like, OHP sheets, cardboard, cardboard, cardboard, and envelopes. It is possible to do. The image forming apparatus 100 is also a double-sided image forming apparatus capable of forming an image on both sides of a transfer sheet that is a recording sheet that is a recording medium as a recording medium.

  The image forming apparatus 100 has a main body 101 that occupies a central position in the vertical direction and functions as a printer unit, a reading device 21 that is a scanner unit that is positioned above the main body 101 and reads a document, and a document is stacked and stacked. An automatic document feeder 22 which is an automatic document feeder called ADF which sends out a document toward the reading device 21, and photosensitive drums 20Y, 20M, 20C and 20BK which are located below the main body 101 and as an image carrier. A sheet feeding device 23 serving as a paper feeding unit serving as a paper feeding device serving as a paper feeding table on which transfer paper conveyed toward the transfer belt 11 serving as a transfer target is loaded.

  The image forming apparatus 100 is a photoconductor drum that is a photoconductor as a plurality of first image carriers that can form images as images corresponding to colors separated into yellow, magenta, cyan, and black. This is a tandem type image forming apparatus employing a tandem structure in which 20Y, 20M, 20C, and 20BK are arranged side by side. The photosensitive drums 20Y, 20M, 20C, and 20BK have the same diameter as each other, and serve as intermediate transfer belts that are intermediate transfer members that are endless belts disposed almost in the center of the main body 101 of the image forming apparatus 100. 2 are arranged at equal intervals on the outer peripheral surface side of the transfer belt 11, that is, the image forming surface side.

  The transfer belt 11 is movable in the arrow A1 direction, which is the clockwise direction in the figure, while facing the respective photosensitive drums 20Y, 20M, 20C, and 20BK. A visible image, that is, a toner image, which is an image formed on each photosensitive drum 20Y, 20M, 20C, 20BK and carried on each photosensitive drum 20Y, 20M, 20C, 20BK, is a transfer belt 11 that moves in the direction of arrow A1. Are transferred onto the transfer paper, and then transferred onto the transfer paper. As described above, the image forming apparatus 100 employs an indirect transfer method which is an intermediate transfer method. Accordingly, the image forming apparatus 100 is a tandem indirect transfer type electrophotographic apparatus.

  In the superimposing transfer to the transfer belt 11, the toner images formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. The transfer charging means as a transfer charger disposed at a position facing each of the photosensitive drums 20Y, 20M, 20C, and 20BK with the transfer belt 11 interposed therebetween, and disposed in contact with the inner peripheral surface of the transfer belt 11. By applying voltage from the primary transfer rollers 12Y, 12M, 12C, and 12BK, which are the primary transfer devices, the timing is shifted from the upstream side toward the downstream side in the A1 direction, and the photosensitive drums 20Y, 20M, 20C, and 20BK are shifted in timing. It is performed at a position directly below, that is, a transfer position which is a primary transfer position.

  The photosensitive drums 20Y, 20M, 20C, and 20BK are arranged in this order from the upstream side in the A1 direction. The photosensitive drums 20Y, 20M, 20C, and 20BK are provided in image stations 60Y, 60M, 60C, and 60BK as image forming units for forming yellow, magenta, cyan, and black images, respectively. Yes. The image stations 60Y, 60M, 60C, and 60BK are arranged along the A1 direction to form a tandem image forming unit.

  The image forming apparatus 100 includes an image forming unit 60 which is an image forming unit as an image forming unit configured by four image stations 60Y, 60M, 60C, and 60BK, and below the photosensitive drums 20Y, 20M, 20C, and 20BK. The transfer belt unit 10 is a transfer unit as a belt unit that is an intermediate transfer unit provided with the transfer belt 11, and the transfer belt on the opposite side of the image forming unit 60 across the transfer belt 11. 11 is arranged to face the transfer belt 11 and rotate in the same direction as the transfer belt 11 at the contact position to the transfer belt 11 to transfer the toner image on the intermediate transfer belt 11 to the transfer paper. A secondary transfer roller 17 serving as a transfer member serving as a secondary transfer device serving as a second transfer unit; A conveyance device 76 serving as a recording medium conveyance device serving as a recording medium conveyance unit as a recording medium conveyance unit that conveys the sheet having the toner image transferred thereon; and a secondary transfer cleaning device 18 that cleans the secondary transfer roller 17. ing.

  The image forming apparatus 100 also includes an optical scanning device 8 that is an exposure device that is an optical writing unit as an optical writing device that is a writing unit that is disposed above the image stations 60Y, 60M, 60C, and 60BK. The transfer paper conveyed from the sheet feeding device 23 is placed between the transfer belt 11 and the secondary transfer belt 5 at a predetermined timing in accordance with the toner image formation timing by the image stations 60Y, 60M, 60C, and 60BK. It has a registration roller pair 13 that is fed out and a sensor (not shown) that detects that the leading edge of the transfer paper has reached the registration roller pair 13.

  The image forming apparatus 100 also has a belt fixing type fixing unit for fixing the toner image onto the transfer paper when the transfer paper transported with the toner image on the transfer belt 11 transferred by the transport device 76 enters. A fixing device 6 as a fixing means, a paper discharge path for discharging the fixed transfer paper to the outside of the main body 101, and a reverse path for conveying the transfer paper toward the registration roller pair 13 again. Disposed below the transporting paper discharge unit 79, the secondary transfer roller 17, the secondary transfer cleaning device 18, the transport device 76, and the fixing device 6 in parallel with the image forming unit 60, images are printed on both sides of the transfer paper. In order to record, when the paper discharge unit 79 transports the transfer paper having an image formed on one side to the reverse path, the transfer paper is switched back and upside down, and again the registration roller pair And a duplex unit 96 is a sheet reversing apparatus for a sheet re-feeding unit for conveying the 3.

  The image forming apparatus 100 also includes a paper discharge tray 75 as a stack unit that is disposed outside the main body 101 and stacks transfer sheets on which image formation has been performed, and a manual sheet feeding device disposed on the right side surface of the main body 101 in FIG. 33, an operation panel (not shown) for operating the image forming apparatus 100, a control means 99 as a control unit for controlling the operation of the entire image forming apparatus 100, a waste toner tank (not shown), and a duct 53 (see FIG. 3). ), A slider (not shown) and a front panel (not shown).

  As shown in FIG. 2, in addition to the transfer belt 11, the transfer belt unit 10 is disposed inside the loop of the transfer belt 11, and the transfer belt 11 is placed on the back side of the transfer belt 11 with the photosensitive drums 20 </ b> Y, 20 </ b> M, 20 </ b> C, 20 </ b> BK. The primary transfer rollers 12Y, 12M, 12C, and 12BK as primary transfer means pressed toward the head and the transfer belt 11 are wound around and the transfer belt 11 is formed into an inverted triangular shape as shown in FIG. The first to third support rollers wound in such a posture, the driving roller 72 as a stretching roller as a rotational driving roller for rotationally driving the transfer belt 11, and the transfer as a repulsive roller as a secondary transfer counter roller The transfer belt 11 is sandwiched between the entrance roller 73 and a tension roller 74 as a driven roller, and the tension roller 74. And a electrostatic cleaning device in the form of an intermediate transfer belt cleaning device 14 is a belt cleaning apparatus as a cleaning means for cleaning the.

  The transfer belt unit 10 also faces the outer peripheral surface of the transfer belt 11 at a position downstream of the image forming unit 60 and upstream of the secondary transfer roller 17 in the A1 direction, specifically at a position facing the driving roller 72. An optical sensor 50 that is a reflection type density sensor that is a reflection type optical sensor as a detection unit that is a detection unit for optically detecting a toner image on the transfer belt 11 in order to perform so-called process control. A belt drive motor (not shown) that moves the transfer belt 11 endlessly in the A1 direction by rotating the roller 72, and image formation is performed with a multicolor image of two or more colors, or a single color image of black only, that is, a monochrome image. The transfer belt unit driving means (not shown) for displacing the transfer belt 11 and the like according to the situation, and the optical sensor 50 are connected to the transfer belt 11. And a holding member (not shown) and held so as to maintain a predetermined distance in a position apart. The rotation driving roller may be constituted by a tension roller 74 or a transfer entrance roller 73. In this case, the other rollers are driven rollers that are driven to rotate.

  When the image formation is performed with two or more multi-color images, the transfer belt unit driving means is configured so that the transfer belt 11 is stretched as shown in FIG. 11 is brought into contact with each of the photosensitive drums 20Y, 20M, 20C, and 20BK, and when image formation is performed with a monochrome image, the transfer belt 11 is displaced to the lower side in the left direction in FIG. , 20C so that the transfer belt 11 contacts only the photosensitive drums 20BK. When the image formation is performed with a monochrome image, the operations of the image stations 60Y, 60M, and 60C are stopped, including the rotation of the photosensitive drums 20Y, 20M, and 20C. In such a configuration, the four image stations 60Y, 60M, 60C, and 60BK are arranged side by side in the order of the image stations 60Y, 60M, 60C, and 60BK from the upstream in the A1 direction, and development as described below is performed. In any case, the image forming unit 60 is disposed on the transfer belt 11 stretched between the tension roller 72 and the drive roller 74. As described above, the order of colors for forming an image varies depending on the aim and characteristics of the image forming apparatus 100 and is not limited.

  The secondary transfer roller 17 is disposed below the transfer belt 11, and abuts on the transfer belt 11 from the surface side of the transfer belt 11 at a place where the transfer belt 11 is wound around by the transfer inlet roller 73. The transfer belt 11 is sandwiched between the transfer belt 11 and the secondary transfer nip as a secondary transfer portion where the transfer belt 11 and the secondary transfer roller 17 are in contact with each other. By applying a secondary transfer bias to the secondary transfer nip, toner images of a maximum of four colors carried on the transfer belt 11 as described later are directed from the transfer belt 11 side to the secondary transfer roller 17 side. A secondary transfer electric field to be electrostatically moved is formed. The toner image is transferred to the transfer paper conveyed between the transfer belt 11 and the secondary transfer roller 17 by the registration roller 13 by a secondary transfer electric field and nip pressure as will be described later.

  As shown in FIG. 2, the conveying device 76 has a conveying belt 5 as an endless conveying member that carries and conveys transfer paper on its upper surface side, and the conveying belt 5 is wound and stretched. A driving roller 15 and a driven roller 16 which are tension rollers; a support member 41 which is positioned inside the conveyor belt 5 and rotatably supports the rotating shaft 15a of the driving roller 15 and the rotating shaft 16a of the driven roller 16; As a first duct through which a fan 42 which is a negative pressure forming means as an air flow forming means disposed below the member 41 and an air flow formed by the fan 42 disposed below the fan 42 are passed. The transport unit 40 having the duct 51 is provided.

  As shown in FIG. 3, the transport device 76 also supports a pair of support plates that rotatably support the transport unit 40 on the front side and the rear side of the main body 101 by rotatably supporting both ends of the rotary shaft 15 a. 43, 44, a support plate 44 on the rear side of the main body 101, a duct 52 as a second duct fixed at a position where it can communicate with the duct 51, and a support plate 43 on the front side of the main body 101. It has a motor 45 as a drive source for rotationally driving the shaft 15a and a stopper (not shown) which will be described later. In addition, in FIG. 3, illustration of the conveyance belt 5 is abbreviate | omitted.

As shown in FIG. 3, a duct 53 as a third duct is fixed at a position where the rear plate 101 a provided in the main body 101 can communicate with the duct 52.
Although not shown in the drawings, the main body 101 is fixed with a slider that slidably supports the support plates 43 and 44 in the left-right direction in FIG. The conveyance device 76 is supported by the slider so as to be movable in the front-rear direction of the main body 101. In order to enable such movement, the conveyance device 76 is unitized and is a unit as a recording medium conveyance unit.

  As shown in FIG. 4, a pair of the conveyance belt 5, the driving roller 15, and the driven roller 16 are provided in the front-rear direction of the main body 101. In addition, illustration of the conveyance belt 5 is abbreviate | omitted in the figure (b).

The conveyor belt 5 is made of rubber and has a hardness of 60 according to JIS-A. The conveyor belt 5 has a large number of holes (not shown) over the entire surface thereof. The material of the conveyor belt 5 is not limited to rubber, and the hardness is optimal if it is in the range of 50 to 65 Hs. By using the belt-like conveyance belt 5 as the conveyance member, it is possible to stably convey the transfer paper even over a long distance. The stability of the transfer paper transport is further improved by carrying the transfer paper in a state of being attracted by the transport belt 5 as will be described later.
The motor 45 rotates the drive shaft 15 by rotating the rotation shaft 15a, thereby rotating the conveyor belt 5 and rotating the driven roller 16 in a driven manner.

  As shown in FIG. 4 or 5, the support member 41 is a pair of suction ports formed on the upper surface of the support belt 41 so as to face the inner surface of the transport belt 5 at a position occupied by the transport belt 5 in the front-rear direction of the main body 101. A hole 41a as a port, a hole 41b as a discharge port formed in the lower surface thereof so as to communicate with the fan 42, and a fourth duct formed therein so as to communicate these holes 41a and 41b. As a duct 54.

  As indicated by arrows in FIG. 5, the fan 42 forms an air flow from the support member 41 side toward the duct 51 side. The fan 42 is provided for sucking air from the holes of the respective conveyor belts 5. During the operation, a negative pressure is formed in the duct 54 through the holes 41b, and each of the holes 41a and the respective conveyor belts communicating with the holes 41a. Outside air is taken into the duct 54 through the five holes. Therefore, the transfer sheet sent to the conveying device 76 by the rotation of the transfer belt 11 and the secondary transfer roller 17 is attracted and carried by each conveying belt 5 and is conveyed along with the rotation of each conveying belt 5.

  The fan 42 is a Sicolro fan, but may be another type of fan such as an axial fan. The fan 42 may be provided inside the support member 41. In this case, the duct 51 is provided for the support member 41.

  As shown in FIG. 5 or FIG. 6, the duct 51 communicates with the fan 42, communicates with the duct 52, the inlet side communication portion 51 a that receives the air flow formed by the fan 42, and the inlet side communication portion. It has the outlet side communication part 51b as a 1st connection part which discharges | emits the airflow received from 51a toward the duct 52. As shown in FIG.

  The duct 51 is fixed in a state where the inlet side communication portion 51 a is connected to the fan 42. The duct 51 allows an air flow formed by the fan 42 to form a negative pressure for adsorbing and supporting the transfer paper to the transport belt 5 from the inlet side connecting portion 51a to the outlet side connecting portion 51b. Yes.

  As shown in FIG. 3 or 6, the duct 52 communicates with the duct 51, and an inlet-side communication portion 52 a as a second connection portion that is formed by the fan 42 and receives the air flow passing through the duct 51 therein. And an outlet side communication part 52 b as a third connection part for discharging the air flow received from the inlet side communication part 52 a toward the duct 53.

  As shown in FIG. 3, the duct 53 communicates with the duct 52, and is formed by the fan 42. The duct 51 and an inlet-side communication portion 53a as a fourth connection portion that receives the air flow passing through the duct 52 therein. And an outlet side communication portion (not shown) that communicates with an exhaust port (not shown) formed in the main body 101 and discharges an air flow received from the inlet side communication portion 53a toward the outside of the main body 101 from the exhaust port.

  The duct 51 and the duct 52 extend so as to extend in the front-rear direction of the main body 101, in other words, the width direction of the transport belt 5, that is, the width direction of the transfer paper transported by the transport belt 5.

Although not shown, the support plate 43 and the support plate 44 support the fixing device 6. Therefore, the conveying device 76 is provided integrally with the fixing device 6.
The conveying device 76 is integrated with the fixing device 6 by a slider, and is attached to the mounting position shown in FIG. 3A and pulled out of the main body 101 from the mounting position shown in FIG. It is supported so as to be displaceable between the drawing positions shown in b). The fixing device 6 is pulled out of the main body 101 together with the transport device 76 when the transport device 76 is displaced from the mounting position toward the pull-out position. Therefore, if the conveying device 76 is pulled out of the main body 101, the fixing device 6 is also pulled out of the main body 101, and the operability for performing access described later is high. This displacement is possible with the front panel open. The displacement of the conveying device 76 and the accompanying displacement of the fixing device and the opening and closing of the front panel are manually performed.

  In a state where the transport device 76 occupies the mounting position, the positions occupied by the transfer belt 11, the secondary transfer roller 17, the transport device 76, and the fixing device 6 are aligned in the front-rear direction of the main body 101. In other words, the conveying device 76 is positioned between the transfer belt 11 and the secondary transfer roller 17 and the fixing device 6 when being in the mounting position, and has been conveyed from the transfer belt 11 and the secondary transfer roller 17. It occupies a position where the transfer sheet S can be received and conveyed to the fixing device 6. Therefore, if the transport device 76 is positioned at the mounting position, the fixing device 6 is also positioned at a position in the main body 101 that should be occupied when image formation is performed, and the image forming apparatus 100 can be image-formed. High operability for

  In a state where the transport device 76 occupies the mounting position, the outlet communication portion 52b and the inlet communication portion 53a are joined in close contact with each other, and the duct 52 and the duct 53 are connected in communication with each other so as to maintain an airtight state. . That is, when the transport device 76 is in the mounting position, the duct 53 is connected to the duct 52, and the air flow passing through the duct 51 and the duct 52 is formed by the fan 42 to adsorb the transfer paper to the transport belt 5. accept.

  In a state where the transport device 76 occupies the pull-out position, the outlet communication portion 52 b and the inlet communication portion 53 a are separated from each other, the duct 52 and the duct 53 are separated, and the duct 53 is separated from the duct 52. That is, the duct 53 is separated from the duct 52 when the transport device 76 is displaced from the mounting position toward the pulling position.

  Further, in a state where the transport device 76 occupies the pulling position, the entire transport device 76 and the fixing device 6 are pulled out of the main body 101, thereby opening the inside of the main body 101, and the inside of the main body 101, the transport device 76, the fixing device. Access to the device 6, for example, maintenance such as jam handling becomes easy. In the state where the transport device 76 occupies the pull-out position, if the access to the transport device 76 and the fixing device 6 is easy, not only the whole is pulled out of the main body 101 but also a part of the main body. 101 may be pulled out.

  As shown in FIG. 7, the transport unit 40 can rotate around the rotation shaft 15a, and the posture can be changed for the purpose of facilitating such access. Specifically, as shown in FIG. 5 (a), the transport unit 40 includes a transport position for transporting the transfer paper by the transport belt 5, and a position where the driven roller 16 is displaced downward and separated from the transport position. It can be displaced between the separation position shown in FIG. Position holding at the transport position is performed by a stopper. The operation of the stopper is performed manually.

  When the transport unit 40 is in the transport position, as shown in FIG. 6, the outlet communication part 51b and the inlet communication part 52a are in close contact with each other, and the duct 51 and the duct 52 communicate with each other so as to maintain an airtight state. Connected with Therefore, the duct 52 is connected to the duct 51 when the transport unit 40 is at the transport position, and receives the air flow formed by the fan 42 to adsorb the transfer paper to the transport belt 5 and passing through the duct 51.

  When the transport unit 40 is in the separation position, the outlet communication portion 51 b and the inlet communication portion 52 a are separated from each other, the duct 51 and the duct 52 are separated from each other, and the duct 52 is separated from the duct 51. In order to facilitate such access, the separation position is set so that the distance between the closest position of the conveyance belt 5 and the fixing device 6 is 30 mm or more when the conveyance unit 40 is in the separation position.

  When the transport unit 40 moves from the disengagement position toward the transport position, the outlet communication part 51b and the inlet communication part 52a come into contact with each other and are connected to each other, as shown in FIG. The transport unit 40 has an inclined surface 51c as a first inclined surface that is a first joint portion that is inclined with respect to a moving direction in which the transport unit 40 moves from the separation position toward the transport position, and the inlet communication portion 52a is The inclined surface 52c is a second inclined surface which is a second joint portion inclined with respect to the moving direction.

  The inclined surface 51c is inclined with respect to the moving direction so that the lower side of the tip on the outlet communication portion 51b side protrudes in the direction in which the duct 51 extends. The inclined surface 52c is inclined with respect to this direction so that the upper side of the tip on the inlet communication portion 51a side protrudes in the direction in which the duct 52 extends. The inclined surface 51c and the inclined surface 52c are formed so that the angles with respect to the moving direction in the state where the transport unit 40 is in the transport position are opposite to each other, and the transport unit 40 is in the state where the transport unit 40 is in the transport position. They are opposed to each other, and their arrangement positions are adjusted so that they can be joined to each other.

  The inclined surface 51c and the inclined surface 52c are joined to each other when the transport unit 40 moves from the disengagement position toward the transport position, whereby the duct 51 and the duct 52 are connected and in communication with each other. Therefore, such a connection and connection are reliably and accurately performed with a simple configuration.

  Further, since both the inclined surface 51c and the inclined surface 52c are inclined with respect to the moving direction in which the conveying unit 40 moves from the separation position toward the conveying position, in other words, when the surfaces are parallel to the moving direction, the conveying is performed. Unlike the case where the unit 40 is parallel to the moving surface, that is, the case where the unit 40 is perpendicular to the width direction of the transfer paper, they do not rub against each other, and wear is prevented or suppressed. The same applies to the case where the transport unit 40 moves from the transport position toward the separation position. Therefore, deterioration such as changes in the shape of the inclined surface 51c, the inclined surface 52c, the outlet connecting portion 51b, and the inlet connecting portion 52a is prevented or suppressed over time, and as a result, the transfer paper 5 is adsorbed by the holes of the conveyor belt 5. A decrease in negative pressure is prevented or suppressed. That is, while maintaining the adhesion of the outlet connecting portion 51b and the inlet connecting portion 52a, particularly the inclined surface 51c and the inclined surface 52c, which are the connecting positions of the duct 51 and the duct 52, the decrease in the negative pressure is prevented or suppressed. The

  In addition, in order to improve the adhesion between the outlet connecting portion 51b and the inlet connecting portion 52a, in other words, to improve the airtightness, at least one of the outlet connecting portion 51b and the inlet connecting portion 52a is formed of an elastic material such as sponge or rubber. It is preferable to arrange a seal member as a member. In this case, the seal member is inclined with respect to the moving direction of the transport unit 40 from the separation position to the transport position, similarly to the slope 51c and the slope 52c, and the seal members or between the seal member and the slope 51c or the slope 52c. It is desirable to form an airtight state by contact. However, when the seal member is provided as an aid for forming an airtight state by the contact between the inclined surface 51c and the inclined surface 52c, the seal member is not limited to the one inclined with respect to the moving direction.

  In addition, the inclined surface 51c and the inclined surface 52c are configured so as not to rub against each other when the transport unit 40 moves from the disengagement position toward the transport position, and as long as the airtight state can be formed. In addition to the planar shape, other shapes such as a stepped shape and a concavo-convex shape that are in close contact with each other may be provided in addition to the planar shape. The first joint portion and the second joint portion are prevented from rubbing each other when the transport unit 40 moves from the separation position toward the transport position, and if such an airtight state can be formed, It may be formed in other shapes such as a stepped shape and an uneven shape.

  In a state where the transport device 76 occupies the mounting position, the transport unit 40 can occupy only the transport position. In a state where the transport device 76 occupies the pull-out position, the transport unit 40 can be set to the separation position. Specifically, when the transport device 76 is pulled out from the mounting position to the pull-out position, the duct 52 and the duct 53 are separated while the duct 51 and the duct 52 remain joined, but the transport device 76 occupies the pull-out position. In this state, the stopper can be released. If the stopper is released, the transport unit 40 can occupy the transport position and the disengagement position, and the joint between the duct 51 and the duct 52 can be released. .

  Therefore, in the state where the transport device 76 occupies the mounting position, the transport unit 40 is not set to the separation position, and therefore the front panel opening operation for confirming that the transport unit 40 occupies the transport position is performed. Is no longer needed. Note that the displacement restricting means for prohibiting the displacement of the transport unit 40 to the separation position while the transport device 76 occupies the mounting position is not limited to the stopper.

  Further, since the displacement of the transport unit 40 to the separation position becomes possible under the condition that the transport device 76 occupies the mounting position, the transport unit 40 may have other configurations on the main body 101 side when performing such a displacement. It is possible to prevent the occurrence of defects due to contact with the.

  With the transport device 76 occupying the mounting position and the transport unit 40 occupying the transport position, the image forming apparatus 100 can form an image, and between the transfer belt 11 and the secondary transfer roller 17 during image formation. The transferred transfer paper is conveyed to the fixing device 6 by the conveying device 76. Therefore, the transport position is a position for transporting the transfer paper by the transport device 76, specifically, the transport belt 5. Further, the mounting position is a position where the transfer paper 76 can be transported by the transport belt 76, specifically the transport belt 5.

Since the fan 42 is driven to attract the transfer paper to the transport belt 5 and transport it, the transport device 76 occupies the mounting position and is driven in a state where the transport unit 40 occupies the transport position.
The motor 45 is driven in synchronization with the drive of the fan 42.

  Driving of the fan 42 and the motor 45 is controlled by the control means 99. The motor 45 may be driven in accordance with the timing when the transfer sheet is conveyed to the conveying device 76 while the fan 42 is being driven.

  In the state where the transport device 76 occupies the pull-out position, even if the transport unit 40 occupies the transport position, as described above, the entire transport device 76 and the fixing device 6 are pulled out of the main body 101 and the inside of the main body 101 is It is opened, and access to the inside of the main body 101, the conveyance device 76, and the fixing device 6 is facilitated. Since a larger space is generated outside, such access can be performed without putting a hand into the main body 101, and such access is further facilitated.

  The intermediate transfer belt cleaning device 14 is downstream of the secondary transfer nip in the A1 direction, and the photosensitive drums 20Y, 20M, 20C, and 20BK on which primary transfer is performed and the primary transfer rollers 12Y, 12M, 12C, and 12BK. The transfer belt 11 is cleaned at a position upstream of the facing region between the photosensitive drum 20Y and the primary transfer roller 12Y which is the most upstream in the A1 direction.

  Although not shown, the intermediate transfer belt cleaning device 14 removes the fur brush, which is a brush roller as a cleaning member in contact with the transfer belt 11 at a position on the transfer belt 11, a blade in contact with the fur brush, and the fur brush as needed. A contact / separation unit that contacts and separates the transfer belt 11 and a voltage application device that applies a voltage in a direction in which the toner on the transfer belt 11 is moved to the fur brush to perform electrical brush cleaning. . The fur brush is provided so as to contact the transfer belt 11 and rotate in the counter direction. The intermediate transfer belt cleaning device 14 cleans the surface of the transfer belt 11 using a fur brush as the transfer belt 11 rotates in the A1 direction. The toner transferred from the transfer belt 11 to the fur brush side by this cleaning is further bladed. Scrape off.

  The fixing device 6 includes a heating roller 62 having a heat source therein, a fixing belt 64 wound around the heating roller 62, a fixing roller 65 wound around the fixing belt 64 together with the heating roller 62, and the fixing roller 65. And a pressure roller 63 that presses against the fixing belt 64 and forms a fixing nip as a fixing portion that is a pressing portion. The heating roller 62, the fixing belt 64, and the fixing roller 65 constitute a belt unit in which the fixing belt 64 moves endlessly. The fixing device 6 passes the transfer paper carrying the toner image through the fixing nip, thereby fixing the carried toner image on the surface of the transfer paper by the action of heat and pressure, that is, by pressurization or heating treatment. It has become.

  The optical scanning device 8 scans and exposes scanning surfaces formed by the surfaces of the photosensitive drums 20Y, 20M, 20C, and 20BK, and performs an optical writing process to form an electrostatic latent image. It has a light source (not shown) that emits beams LY, LM, LC, and LBK, which are laser beams as laser beams based on image signals. The light source is a laser diode, but may be an LED or the like.

  The beams LY, LM, LC, and LBK are generated by the control means 99 based on the original read by the reading device 21, the received data in the facsimile, and image information input from an external input device such as a PC as will be described later. An image signal, which is electronic information corresponding to an image to be formed, constituting each color plate is converted into optical information.

  The optical scanning device 8 emits beams LY, LM, LC, and LBK from the light source by controlling the driving of the light source by the control means 99 based on the image information, and outputs the light information to the photosensitive drums 20Y and 20M. , 20C and 20BK are fixed as latent images. The light source is not limited to the laser system such as the optical scanning device 8, and may be an exposure apparatus using another system such as an LED system.

  As shown in FIG. 1, the paper discharge unit 79 discharges the fixed transfer paper conveyed from the fixing device 6 toward the duplex unit 96, and discharges it outside the main body 101. A discharge roller 98 as a pair of discharge rollers stacked on 75 and the fixed transfer paper are guided to a discharge path having a conveyance roller 97 and discharged to the outside of the main body 101 or led to a reverse path having a discharge roller 98. And a switching claw 94 for switching whether to enter the duplex unit 96.

  The duplex unit 96 is transported from the sheet discharge unit 79, and includes a tray 92 as a paper feed box on which transfer paper having an image formed on one surface is temporarily stacked, and a reverse roller for switching back the transfer paper on the tray 92. 93 and a paper feed roller 95 for feeding the transfer paper switched back by the reverse roller 93 toward the registration roller 13.

  The sheet feeding device 23 is a paper as a paper feeding box that is arranged in multiple stages so that a plurality of paper feeding cassettes 25 as a paper feeding tray that can store a plurality of transfer papers in a bundle of sheets are stacked in the vertical direction. A bank 26, a feed roller 24 as a feed roller that contacts the upper surface of the uppermost transfer paper among the transfer papers loaded in the paper feed cassette 25, and one transfer paper fed out by the feed roller 24 There are a separation roller 27 that separates each one, and a paper feed roller 24 and a paper feed path 29 through which the transfer paper fed by the separation roller 27 passes.

  The paper feed path 29 includes a transport roller 28 serving as transport means for transporting the transfer paper fed by the paper feed roller 24 and the separation roller 27 toward the registration roller pair 13, and a downstream end in the transfer paper transport direction. A transfer roller sheet feeding device 23 transported by a transport roller 28, and is continuously provided in the main body 101, and is also transported to a paper feed path 29 in the main body 101. A roller 28 is provided.

  In the sheet feeding device 23, the feeding roller 24 is rotated in the counterclockwise direction in the drawing, and the separation roller 27 acts to guide the uppermost transfer paper into the paper feeding path 29, so that the conveying roller 28 The sheet is fed toward the registration roller pair 13 by the rotation, and the transferred transfer paper abuts against the registration roller pair 13 to be stopped and the skew is corrected.

  The manual paper feeder 33 is a manual feed tray 34 as a paper feed box on which transfer paper is stacked, and feed as a paper feed roller that contacts the upper surface of the uppermost transfer paper among the transfer papers stacked on the manual feed tray 34. A roller 35, a separation roller 36 that separates the transfer paper fed by the feeding roller 35 one by one, a manual paper feed path 37 that joins the paper feed path 29 in the main body 101, and a transfer paper on the manual tray 34. And a paper sensor for detecting that the paper is placed.

  In the manual sheet feeding device 33, the feeding roller 35 is rotated in the clockwise direction in the drawing, and the separation roller 36 acts to join the uppermost transfer sheet to the sheet feeding path 29 in the main body 101. The paper is fed to the manual paper feed path, guided from the manual paper feed path 37 into the paper feed path 29 and fed toward the registration roller pair 13 so that the transferred transfer paper abuts against the registration roller pair 13 and is stopped. It has become.

  The reading device 21 includes a contact glass 21a on which a document is placed, a light source (not shown) that irradiates light on the document placed on the contact glass 21a, and a first light source (not shown) that reflects light reflected from the light source. A first traveling body 21b that includes a reflector and travels in the left-right direction in FIG. 1; a second traveling body 21c that includes a second reflector (not shown) that reflects light reflected by the reflector of the first traveling body 21b; An image forming lens 21d for forming an image of light from the second traveling body 21c, a reading sensor 21e for receiving the light passing through the image forming lens 21d and reading the contents of the document are provided.

The reading device 21 transmits image information of the document read by the reading sensor 21e to the control means 99.
The automatic document feeder 22 has a document table 22a on which a document is placed. The automatic document feeder 22 is rotatable with respect to the reading device 21, and the contact glass 21a is exposed when the automatic document feeder 22 is rotated upward.

The operation panel is an operation display unit having a liquid crystal display, a start button that functions as a copy start switch for starting copying, and various key buttons such as a numeric keypad for inputting the number of copies. On the operation panel, it is possible to specify whether image formation is performed with a multicolor image or a monochrome image, and it is possible to set a single-sided print mode, which is a mode for forming an image only on one side of a transfer sheet. Yes. The single-sided print mode includes a direct discharge mode, a reverse discharge mode, and a reverse decal discharge mode, and one of these is selected.
The control means 99 includes a CPU, a ROM as a memory means, a RAM, and the like.

  Regarding the image stations 60Y, 60M, 60C, and 60BK, the configuration will be described as a representative of the configuration of the image station 60Y including the photosensitive drum 20Y. Since the configurations of the other image stations 60M, 60C, and 60BK other than the image station 60Y are substantially the same, in the following description, for the sake of convenience, the configuration of the image station 60Y including the photosensitive drum 20Y is attached. The reference numerals corresponding to the reference numerals are attached to the configurations of the other image stations 60M, 60C, and 60BK, and detailed descriptions thereof are omitted as appropriate. Y, M, C, and BK are added to the end of the reference numerals. Indicates a configuration for forming an image of yellow, magenta, cyan, and black, respectively.

  As shown in FIG. 2, the image station 60Y provided with the photoconductive drum 20Y is a transfer unit 1 around the photoconductive drum 20Y along a rotation direction B1 that is a counterclockwise direction in the drawing. As a secondary transfer roller 12Y, a cleaning device 70Y as a primary transfer cleaning device which is a photosensitive member cleaning device as a cleaning means as a cleaner portion, a static elimination device 90Y as a static elimination means as a static elimination portion, and a uniform charging means as a charging portion. A charging device 30Y as a charging unit as a charging unit, and a developing device 80Y as a developing unit as a developing means as a developing unit.

  The image station 60Y also has a cartridge case 59Y in which these components around the photosensitive drum 20Y are integrated, and a primary transfer bias of positive polarity that is opposite to the negative polarity that is the normal charging polarity of the toner. A power source (not shown) to be applied to the transfer roller 12Y and a driving means (not shown) for rotating the photosensitive drum 20Y in the B1 direction are provided.

  The photosensitive drum 20Y, the cleaning device 70Y, the charge eliminating device 90Y, the charging device 30Y, and the developing device 80Y are integrated by a cartridge case 59Y, and constitute an image station 60Y as a process cartridge. The image station 60Y as a process cartridge can draw out the cartridge case 59Y from the main body 101 along a guide rail (not shown) fixed to the main body 101, and can push the cartridge case 59Y into the main body 101. It is detachably installed and can be exchanged in a timely manner.

  When pushed into the main body 101, the image station 60Y as a process cartridge is loaded and positioned at a predetermined position suitable for image formation. Making a process cartridge in this way is very preferable because it can be handled as a replacement part, so that the maintainability is remarkably improved. In addition, since the life of each part, which is an element of the process cartridge, is equal, unnecessary replacement is prevented and suppressed, and the structure is further preferable.

  The image station 60Y as a process cartridge includes a photosensitive drum 20Y, a cleaning device 70Y, a charge eliminating device 90Y, a charging device 30Y, and a developing device 80Y. At least the photosensitive drum 20Y includes a cleaning device 70Y and a charge eliminating device. The unit is configured to be integrated with at least one of the device 90Y, the charging device 30Y, and the developing device 80Y, and is detachably installed on the main body 101. The entire image forming unit 60 constituted by the four image stations 60Y, 60M, 60C, and 60BK may be a process cartridge, and these may be integrally attached to and detached from the main body 101.

  A primary transfer nip formed by the primary transfer roller 12Y pressing the transfer belt 11 toward the photosensitive drum 20Y is a contact position between the transfer belt 11 and the photosensitive drum 20Y. The toner image is transferred to the transfer belt 11 and constitutes a transfer position. The power source of the primary transfer roller 12Y applies a predetermined transfer bias to the primary transfer roller 12Y by constant voltage control. The primary transfer device is not limited to the roller shape as in the present embodiment, but may be configured by a conductive brush shape, a non-contact corona charger, or the like.

  The static eliminator 90Y includes a static elimination lamp (not shown) disposed in the vicinity of the surface of the photoconductor drum 20Y, and the surface of the photoconductor drum 20Y is neutralized by making it electrically clean. Is initialized.

  Although not shown, the charging device 30Y includes a charging roller as a charging member that rotates in contact with the surface of the photosensitive drum 20Y, and a cleaning roller as a charging cleaning member that rotates in contact with the charging roller. doing.

  The charging roller is connected to a voltage applying means (not shown) that superimposes and applies an AC component charging bias to a direct current, and in the charging region facing the photosensitive drum 20Y, the charging drum 90Y is charged by the discharging device 90Y. The surface is uniformly charged to a predetermined polarity.

The cleaning roller is driven and rotated by the charging roller to clean the charging roller.
As described above, in this embodiment, a charging system using a contact roller is adopted. However, the charging system may use a proximity roller or a non-contact scorotron charger. There may be.

  The developing device 80Y includes a developing roller 81Y as a developing member that carries a developer that is a two-component developer including toner and a carrier disposed in close proximity to the photosensitive drum 20Y, and a DC component applied to the developing roller 81Y. (Not shown) for applying a developing bias, a toner cartridge (not shown) containing toner, and a toner concentration (not shown) for detecting a toner concentration which is a weight percentage of the toner in the developer in the main body of the developing device 80Y. The main body of the developing device 80Y from the toner cartridge so that the toner density detected by the detection means and the toner density detection means becomes a predetermined density, that is, the value indicated by the detection signal from the toner density detection means becomes a predetermined control target value. And a toner replenishing means (not shown) for replenishing the toner. The developer is a two-component developer including a magnetic carrier and a yellow toner that is a color toner having a negative regular charge polarity. The developing bias applied by the bias applying unit may be an alternating current component instead of a direct current component, or may be an alternating current component superimposed on the direct current component.

  A beam LY emitted from the optical scanning device 8Y is irradiated between the charging device 30Y and the developing device 80Y on the surface of the photosensitive drum 20Y, and the surface of the photosensitive drum 20Y after being charged by the charging device 30Y. The surface to be scanned is exposed, and an electrostatic latent image corresponding to image information that is visualized as a yellow toner image is written by the developing device 80Y. The portion irradiated with the beam LY is exposed. Has become a department.

  The cleaning device 70Y is shown as a cleaning member whose tip is in contact with the photosensitive drum 20Y and scrapes and collects and removes foreign matters such as transfer residual toner, carrier, and paper dust on the photosensitive drum 20Y. And a waste toner conveying means (not shown) that conveys and collects the collected transfer residual toner to a waste toner tank. The cleaning device 70Y may use a fur brush roller together with the cleaning blade or instead of the cleaning blade, or may employ a magnetic brush cleaning method.

  In the image station 60Y having the above-described configuration, the surface of the photosensitive drum 20Y is uniformly charged by the charging device 30Y along with the rotation in the B1 direction during image formation, and the light from the optical scanning device 8Y. By this exposure scanning, the potential of the photosensitive drum 20Y in the exposure portion, that is, the irradiation portion is attenuated to form an electrostatic latent image corresponding to yellow, and this electrostatic latent image is developed by the developing device 80Y with yellow toner. The yellow toner image developed and developed by this development process is primarily transferred to the transfer belt 11 moving in the A1 direction by the primary transfer electric field and nip pressure formed by the primary transfer roller 12Y, and transferred. Unnecessary substances including toner remaining after the removal are removed by the cleaning device 70Y, and the next neutralization device 90Y and the charging device 30Y Electrodeposition is subjected to charging.

  In the image forming apparatus 100 having such a configuration, when copying is performed, a document is set on the document table 22a of the automatic document feeder 22 or the automatic document feeder 22 is rotated upward to be on the contact glass 21a. After the document is placed on the automatic document feeder 22, the automatic document feeder 22 is rotated downward to close the document and press the document, and then the start button on the operation panel is pressed. The document set on the automatic document feeder 22 is, for example, a bundle-shaped sheet document, and the document set on the contact glass 21a is, for example, a single-bound document that is bound in a main shape. When the image forming apparatus 100 is used as a printer, an image forming start operation is performed after image data to be formed is selected and input by an external input device such as a PC connected to the image forming apparatus 100. Here, it is assumed that a color image is copied.

  When copying is performed and the document is set on the document table 22a, the document is read by the reading device 21 after the set document is sent onto the contact glass 21a. When the document is placed on 21a, the reading device 21 reads the document when the start button is pressed, and image data is generated.

  Reading of a document by the reading device 21 is performed as follows. When the start button is pressed, the first traveling body 21b and the second traveling body 21c start traveling along the document surface of the document placed on the contact glass 21a, and the first traveling body 21b emits light emitted from the light source. While reflecting on the document surface, the reflected light obtained is reflected toward the second traveling body 21c. The folding light from the first traveling body 21b is further folded by the second traveling body 21c, and then enters the reading sensor 21e through the imaging lens 21d, whereby the document content is read.

  Based on the generated image data or the input image data, the image stations 60Y, 60M, 60C, and 60BK having the above-described configuration operate. In parallel with the document reading operation, the devices in the image stations 60Y, 60M, 60C, and 60BK, which are the process cartridges, the transfer belt unit 10, the secondary transfer unit 76, the fixing device 6 and the like are driven. Start.

  In the image station 60Y, as described above, the surface of the photosensitive drum 20Y is uniformly charged by the charging device 30Y prior to the optical writing process by the optical scanning device 8 in accordance with the rotation in the B1 direction. The electrostatic latent image is formed by the optical scanning device 8 and the optical writing processing is performed. The electrostatic latent image is developed with yellow toner by the developing device 80Y, and the development processing is performed. The yellow toner image is primarily transferred to the transfer belt 11 by the primary transfer roller 12Y. Unnecessary materials including toner remaining after the transfer are removed by the cleaning device 70Y, and then the neutralization device 90Y and the charging device 30Y perform the next operation. It is used for static elimination and charging.

  In the other photoconductor drums 20C, 20M, and 20BK, the toner images of the respective colors are similarly formed while maintaining the good state, and the formed toner images of the respective colors are the primary transfer rollers 12M, 12C, By 12BK, primary transfer is sequentially performed at the same position on the transfer belt 11 moving in the A1 direction. At this time, the primary transfer rollers 12 </ b> Y, 12 </ b> M, 12 </ b> C, and 12 </ b> BK are applied with a positive polarity voltage opposite to the negative polarity that is the normal charging polarity of the toner.

  A four-color superimposed toner image constituted by toner images superimposed on the transfer belt 11, that is, a four-color toner image, is a position facing the secondary transfer roller 17 as the transfer belt 11 rotates in the A1 direction. The transfer sheet is moved to the next transfer nip and is secondarily transferred to the transfer sheet in close contact with the transfer belt 11 by the action of the secondary transfer electric field, which is a nip pressure or a transfer electric field, and a full color image is carried on the transfer sheet.

  The transfer paper conveyed between the transfer belt 11 and the secondary transfer roller 17 is selected by one feeding roller 24 of the sheet feeding device 23 according to the size corresponding to the image information when the start button is pressed. The paper is fed from the corresponding paper feed cassette 25 by this rotation and introduced into the paper feed path 29 and fed, or is fed from the manual feed tray 34 by the rotation of the feed roller 35 of the manual paper feed device 33. Whether the paper is fed from the manual paper feed path 37 to the paper feed path 29 or is fed from the duplex unit 96 by the paper feed roller 95 and introduced into the paper feed path 29 and fed. Between the rollers by the registration roller pair 13 and on the transfer belt 11 based on a detection signal from the sensor. In which the distal end portion of the toner image is sent out at a timing opposite to the secondary transfer roller 17. Such a feed operation is started substantially simultaneously with the document reading operation described above.

  When the toner images of all colors are transferred and carried on the transfer paper, the transfer paper is reliably conveyed while being adsorbed by the conveying device 76 and sent to the fixing device 6, and a fixing portion between the fixing belt 64 and the pressure roller 63. When the toner image is passed through the fixing unit, the carried toner image is fixed by the action of pressure and heat, that is, pressurization or heat treatment, and a good color image is formed on the transfer paper. The fixed transfer paper that has passed through the fixing device 6 is stacked on the paper discharge tray 75 via the paper discharge roller 98 or via the transport roller 97 depending on the position of the switching claw 94. In 96, the sheet is returned to the registration roller pair 13 again to prepare for double-sided image formation through the secondary transfer nip and the fixing device 6 again.

  On the other hand, the photosensitive drums 20Y, 20M, 20C, and 20BK that have undergone the primary transfer are cleaned by removing transfer residual toner and the like remaining thereon by the cleaning devices 70Y, 70M, 70C, and 70BK, and are used for the next image formation. Prepare. The transfer belt 11 that has undergone the secondary transfer is cleaned by removing the transfer residual toner or the like remaining on the intermediate transfer belt cleaning device 14 to prepare for the next image formation.

  During such an image forming operation, if it is necessary to perform maintenance such as jamming of transfer paper in the transport device 76, the fixing device 6 or the periphery thereof, the transport device 76 is pulled out to the pull-out position and is necessary. In addition to this, the maintenance is easily and satisfactorily performed by displacing the transport unit 40 to the separation position.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.
For example, since the recording medium is transported by the recording medium transporting device by being attracted to the transporting member, the transporting direction in the transporting may be other directions such as the vertical direction instead of the horizontal direction.

  Even if the image forming apparatus is a tandem type, a direct transfer system can be adopted instead of the indirect transfer system described above. The image forming apparatus is not a so-called tandem type image forming apparatus, but a so-called one-drum type image forming apparatus that sequentially forms toner images of respective colors on a single photosensitive drum and sequentially superimposes the color toner images to obtain a color image. The intermediate transfer member can be applied to the image forming apparatus in the same manner, and in addition, the toner image of each color is developed on an image carrier such as a sheet-like organic photoreceptor, but the color superposition itself is separate. The present invention can be similarly applied to an image forming apparatus such as a method using a toner, a method using a plurality of intermediate transfer members, or a method using intermediate color toner.

  When an intermediate transfer member is used, an image carried on the intermediate transfer member is transferred to a recording medium using the intermediate transfer member as an image carrier as described above. When the carried image is transferred to the recording medium, a photoconductor or the like is used as the image carrier.

In addition, in recent years, in accordance with demands from the market, color image forming apparatuses, such as color copiers and color printers, have increased in number, but image forming apparatuses can only form monocolor images. It may be.
The developer used in such an image forming apparatus is not limited to a two-component developer but may be a one-component developer.

  The image forming apparatus is not a copier, a printer, or a facsimile machine, but may be a single machine or a plotter, or other machine such as a copier / printer machine. It may be a combined multifunction machine.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 5 Conveyance member 6 Fixing means 11 Image carrier 17 Transfer means 40 Conveyance unit 51 1st duct 51c 1st inclined surface 52 2nd duct 52c 2nd inclined surface 53 3rd duct 76 Recording-medium conveyance apparatus 100 Image Forming device 101 body

JP 2005-187092 A Japanese Patent No. 4322108

Claims (3)

A transport unit comprising a transport member that carries and transports a recording medium, and a first duct through which an air flow passes to form a negative pressure for adsorbing and supporting the recording medium on the transport member;
When the transport unit is at a transport position for transporting a recording medium by the transport member, the transport unit is connected to a first duct to receive the air flow from the first duct, and the transport unit is separated from the transport position. Having a first duct and a second duct separated when in the disengaged position;
Each of the first duct and the second duct is inclined with respect to a moving direction in which the transfer unit moves from the separation position toward the transfer position and can be joined to each other. And has a surface,
When the transport unit moves from the separation position toward the transport position, the first inclined surface and the second inclined surface are joined to each other, thereby connecting the first duct and the second duct. a recording medium conveying device that,
The recording medium transport device is displaceable between a mounting position mounted in the main body, which can transport the recording medium by the transport member, and a pull-out position pulled out from the mounting position toward the outside of the main body. In the image forming apparatus, the transport unit can be set to the separation position in a state where the recording medium transport device is in the pull-out position.
When the recording medium transport apparatus is in the mounting position, the recording medium transport apparatus is connected to a second duct and receives the air flow from the second duct, and the recording medium transport apparatus is displaced from the mounting position toward the pulling position. An image forming apparatus comprising a third duct separated from the second duct. In images forming apparatus according to claim 1,
Having fixing means for fixing the image carried on the recording medium to the recording medium;
The recording medium conveying device is provided integrally with the fixing unit, and conveys the recording medium to the identification attaching unit when in the attachment position.
The image forming apparatus , wherein the fixing unit is pulled out of the main body when the recording medium transport device is displaced from the mounting position toward the pulling position . The image forming apparatus according to claim 2.
Having transfer means for transferring an image on the image carrier to a recording medium;
The conveying member is located between the transfer unit and the fixing unit when the recording medium conveying apparatus is at the mounting position, and a recording medium on which an image on the image carrier is transferred by the transfer unit. An image forming apparatus conveyed to the fixing unit .

Images