JP2009271469A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of sufficiently exhibiting a cooling effect to cool a transferred material by an air blowing means for blowing air to a reverse conveyance path. <P>SOLUTION: The image forming apparatus includes: a housing M1; a fixing part; a discharge conveyance path 510 for discharging the transferred material outside the housing M1; a reverse conveyance path 520; a joint conveyance path 530 for joining the transferred material to the discharge conveyance path 510; the air blowing means 551 for blowing the air A to the reverse conveyance path 520; a conveyance path switching means 540 for switching the conveyance destination of the transferred material between the discharge conveying path 510 and the reverse conveyance path 520; first ventilation openings 560 formed in a reverse conveying path forming member 521 that forms the reverse conveyance path 520; second ventilation openings 570 and third ventilation openings 580 separately formed in a pair of joint conveyance path forming members 531 and 532 for forming the joint conveyance path 530; and an air discharging means 552 for discharging the air A outside the housing M1 through the first, second and third ventilation openings 560, 570 and 580. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In an image forming apparatus such as a copying machine, an image forming unit that forms an image on a sheet that is a transfer material, a fixing unit that fixes an image formed on the sheet by the image forming unit, and a fixing unit Out-of-machine discharge conveyance path for discharging the discharged sheet to the outside of the casing, a reversal conveyance path for inverting the front and back surfaces of the sheet branched from the out-of-machine discharge conveyance path and discharged from the fixing unit, and reverse conveyance And a merging conveyance path that merges a sheet passing through the path into an out-of-machine discharge conveyance path (for example, see Patent Document 1 below).

In the image forming apparatus described in Patent Document 1, the first branching portion where the reversing conveyance path branches from the out-of-machine discharge conveying path is provided on the side opposite to the reversing conveyance path, and is directed to the reversing conveyance path. Air supply means (fan) for blowing air and an air passage part (opening part) for passing the air blown from the air supply means, provided at the first branch part, and conveying the sheet to the outside discharge conveyance Transport path switching means (switching gate) for switching to the path or the reversing transport path.
In the image forming apparatus described in Patent Document 1, since the sheet discharged from the fixing device (fixing unit) can be cooled by the air blown from the air feeding means, the toner transferred to the sheet is quickly cooled. In addition, it is possible to prevent the unfixed toner from being rubbed and peeled off, and the image can be reliably fixed on the sheet.

JP 2005-112568 A

  However, in the image forming apparatus described in Patent Document 1, no consideration is given to discharging the air that is heated by cooling the sheet to the outside of the housing. Therefore, in the image forming apparatus described in Patent Document 1, hot air is likely to accumulate inside the housing, and therefore, the cooling effect of the sheet (transfer material) by the air supply means is not sufficiently achieved.

  Accordingly, the present invention provides an air supply that is provided on the opposite side of the reversing conveyance path with respect to the first branch portion where the reversing conveyance path branches from the out-of-machine discharge conveyance path, and blows air toward the reversing conveyance path. And an air passage portion that is provided in the first branching section and allows the air blown from the air feeding means to pass therethrough, and the conveyance path switching for switching the transfer destination of the transfer material to the out-of-machine discharge conveyance path or the reverse conveyance path. In the image forming apparatus including the image forming apparatus, the air inside the housing can be quickly discharged to the outside of the housing, so that the image forming apparatus can sufficiently exhibit the cooling effect of the transfer material by the air feeding device. An object is to provide an apparatus.

  The present invention includes a housing, an image forming unit that forms an image on a sheet-like transfer material, a fixing unit that fixes an image formed on the transfer material by the image forming unit to the transfer material, and the fixing An outside discharge conveyance path for discharging the material to be transferred discharged from the section to the outside of the housing, and the front and back surfaces of the transfer material discharged from the fixing section are branched from the outside discharge conveyance path. A reversing conveyance path, a merging conveyance path for joining the material to be transferred via the reversing conveyance path to the off-machine discharge conveyance path, and the reversal conveyance path from the off-machine discharge conveyance path. An air supply means that is provided on the opposite side of the reversing conveyance path with respect to the first branching section, and that blows air toward the reversing conveyance path, and is provided in the first branching section, from the air supply means It has an air passage part that allows the air to be blown to pass through, A conveyance path switching means for switching to an out-of-machine discharge conveyance path or the reversing conveyance path, a first ventilation opening provided in a reversing conveyance path forming member that forms the reversing conveyance path, and the merging conveyance path are formed. A second vent opening and a third vent opening provided in a pair of opposing confluence conveying path forming members, and the first vent opening provided between the housing and the confluence conveying path. And an exhaust unit that sucks air from the air supply unit and discharges the air to the outside of the housing through the second ventilation opening and the third ventilation opening.

  Further, it is preferable that the air that has passed through the air passing portion is blown toward the image forming surface side of the transfer material.

  Each of the second ventilation opening and the third ventilation opening is composed of a plurality of long holes, and the plurality of long holes move toward the first direction as the transfer direction of the transfer material. It is preferable to extend so as to spread in a third direction which is a direction orthogonal to the second direction which is the direction and the second direction which is a facing direction of the pair of confluence conveyance path forming members.

  Further, it is preferable that the second ventilation opening and the third ventilation opening substantially overlap when viewed in a direction from the second ventilation opening toward the exhaust unit.

  In the second ventilation opening and the third ventilation opening, air that has passed through the second ventilation opening and the third ventilation opening is blown to both ends of the transfer material along the first direction. It is preferable that it is comprised.

  According to the present invention, the air supply that is provided on the opposite side of the reversing conveyance path with respect to the first branching portion where the reversing conveyance path branches from the out-of-machine discharge conveyance path and blows air toward the reversing conveyance path. And an air passage portion that is provided in the first branching section and allows the air blown from the air feeding means to pass therethrough, and the conveyance path switching for switching the transfer destination of the transfer material to the out-of-machine discharge conveyance path or the reverse conveyance path. In the image forming apparatus including the means, the hot air inside the casing can be quickly discharged to the outside of the casing, so that the transfer material can be sufficiently cooled by the air feeding means.

The best mode for carrying out the present invention will be described below with reference to the drawings.
First, the overall structure of the color copier 1 as an image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a left side view for explaining the arrangement of each component in the color copier 1. In the present embodiment, the side (the right side in FIG. 1) on which a later-described manual feed tray 65 is disposed is the front side of the color copier 1.

  A color copying machine 1 as an image forming apparatus includes a document feeding unit 70 that is arranged on the upper side and feeds a predetermined document, an image reading unit 71 that reads an image formed on a document fed by the document feeding unit 70, and a lower part. And an apparatus main body M that forms a toner image on a sheet T based on image information from the image reading unit 71.

The apparatus main body M includes an image forming unit that forms an image on the paper T inside the housing M1, and a fixing device 9 that is a fixing unit that fixes the image formed on the paper T by the image forming unit to the paper T. . Specifically, the apparatus main body M includes photosensitive drums 2a, 2b, 2c, and 2d as image carriers, charging units 10a, 10b, 10c, and 10d, laser scanner units 4a, 4b, 4c, and 4d, and development. Devices 16a, 16b, 16c, 16d, toner cartridges 5a, 5b, 5c, 5d, toner supply devices 6a, 6b, 6c, 6d, intermediate transfer belt 7, and primary transfer rollers 37a, 37b, 37c, 37d. And an intermediate transfer unit 200 including the secondary transfer roller 8 and a fixing device 9.
In addition, the apparatus main body M includes a paper feed cassette 52 that is disposed so as to be able to be pulled out below the apparatus main body M and that stores the sheets T in a stacked state. Further, the apparatus main body M includes a transport path 54 through which the paper T sent out from the paper feed cassette 52 is transported.

  The photosensitive drums 2a, 2b, 2c, and 2d are cylindrical members. Each of the photosensitive drums 2a, 2b, 2c, and 2d is disposed so as to be rotatable in the direction of an arrow about a rotation axis perpendicular to FIG. An electrostatic latent image is formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d.

  The charging units 10a, 10b, 10c, and 10d are disposed above the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The charging units 10a, 10b, 10c, and 10d uniformly and positively (positively) charge the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d.

  The laser scanner units 4a, 4b, 4c, and 4d are disposed above the photosensitive drums 2a, 2b, 2c, and 2d and spaced apart from the photosensitive drums 2a, 2b, 2c, and 2d, respectively. Each of the laser scanner units 4a, 4b, 4c, and 4d includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  Each of the laser scanner units 4a, 4b, 4c, and 4d scans and exposes the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d based on the image information related to the image read by the image reading unit 71. Scanning exposure is performed by each of the laser scanner units 4a, 4b, 4c, and 4d, so that charges charged on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d are removed. Thereby, electrostatic latent images are formed on the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d.

  Each of the developing devices 16a, 16b, 16c, and 16d is provided corresponding to each of the photosensitive drums 2a, 2b, 2c, and 2d, and beside the photosensitive drums 2a, 2b, 2c, and 2d (left side in FIG. 1). Be placed. Each of the developing devices 16a, 16b, 16c, and 16d develops toner images of the respective colors on the electrostatic latent images formed on the photosensitive drums 2a, 2b, 2c, and 2d. Each of the developing devices 16a, 16b, 16c, and 16d corresponds to four toner colors of yellow, cyan, magenta, and black. Each of the developing devices 16a, 16b, 16c, and 16d includes developing rollers 116a, 116b, 116c, and 116d that can be disposed to face the photosensitive drums 2a, 2b, 2c, and 2d, and a stirring roller for stirring the toner. The

  Each of the toner cartridges 5a, 5b, 5c, and 5d is provided corresponding to each of the developing devices 16a, 16b, 16c, and 16d, and each color toner supplied to each of the developing devices 16a, 16b, 16c, and 16d. To accommodate. Each of the toner cartridges 5a, 5b, 5c, and 5d accommodates yellow toner, cyan toner, magenta toner, and black toner.

  The toner supply devices 6a, 6b, 6c, and 6d are provided corresponding to the toner cartridges 5a, 5b, 5c, and 5d and the developing devices 16a, 16b, 16c, and 16d, respectively. The toners of the respective colors accommodated in 5d are supplied to the developing devices 16a, 16b, 16c, and 16d, respectively.

  The toner images of the respective colors developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially transferred to the intermediate transfer belt 7. The intermediate transfer belt 7 is arranged so as to be stretched between the driving roller 35 and the tension roller 36. Since the tension roller 36 is biased to the side away from the drive roller 35 by the spring 38, a predetermined tension is applied to the intermediate transfer belt 7.

  Primary transfer rollers 37a, 37b, 37c, and 37d are arranged to face each other on the opposite side of the intermediate transfer belt 7 from the photosensitive drums 2a, 2b, 2c, and 2d.

  Predetermined portions of the intermediate transfer belt 7 are sandwiched between the primary transfer rollers 37a, 37b, 37c, and 37d and the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The predetermined portion thus sandwiched is pressed against the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. In this way, primary transfer nips N1a, N1b, N1c, and N1d are formed, and the color toner images developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially transferred to the intermediate transfer belt 7. As a result, a full-color toner image is formed on the intermediate transfer belt 7.

  The primary transfer rollers 37a, 37b, 37c, and 37d are respectively transferred to the intermediate transfer belt 7 with the respective color toner images developed on the photosensitive drums 2a, 2b, 2c, and 2d by a voltage application unit (not shown). The primary transfer bias is applied.

  The secondary transfer roller 8 secondarily transfers the toner image primarily transferred to the intermediate transfer belt 7 onto the paper T. A secondary transfer bias for transferring the toner image on the intermediate transfer belt 7 to the paper T is applied to the secondary transfer roller 8 by a voltage application unit (not shown).

  The secondary transfer roller 8 is brought into contact with and separated from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is configured to be movable between a contact position where the secondary transfer roller 8 is in contact with the intermediate transfer belt 7 and a spaced position where the secondary transfer roller 8 is separated from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is moved to the contact position when the toner image primarily transferred onto the surface of the intermediate transfer belt 7 is secondarily transferred to the paper T, and is separated from the other position. Moved to. Here, the contact / separation operation of the secondary transfer roller 8 is performed by rotating the entire intermediate transfer unit 200.

  The secondary transfer roller 8 is included in the intermediate transfer unit 200. The intermediate transfer unit 200 accommodates the secondary transfer roller 8 and rotatably supports the secondary transfer roller 8, a rotation drive gear 210 disposed on the side surface of the housing 201, and the secondary transfer roller 8, a roller side gear 220 disposed on the side surface of the housing 201 and an idle gear 230 disposed in contact with the rotation drive gear 210 and the roller side gear 220. The intermediate transfer unit 200 has a position where the secondary transfer roller 8 can contact the intermediate transfer belt 7 around a rotation shaft (not shown) by a contact / separation means (not shown), and a position where the intermediate transfer unit 200 does not contact the intermediate transfer belt 7. Is rotated.

  A counter roller 108 is disposed on the side of the intermediate transfer belt 7 that faces the secondary transfer roller 8. A predetermined portion of the intermediate transfer belt 7 is sandwiched between the secondary transfer roller 8 and the opposing roller 108. Then, the paper T is pressed against the surface of the intermediate transfer belt 7 (the side on which the image is primarily transferred). In this way, the secondary transfer nip N2 is formed, and the toner image primarily transferred to the intermediate transfer belt 7 is secondarily transferred to the paper T.

  The fixing device 9 melts and fixes each color toner constituting the toner image secondarily transferred onto the paper T. The fixing device 9 includes a heating roller 9a heated by a heater, and a pressure roller 9b pressed against the heating roller 9a. The heating roller 9a and the pressure roller 9b convey the paper T onto which the toner image is secondarily transferred so as to sandwich the paper T. By being conveyed so as to be sandwiched between the heating roller 9a and the pressure roller 9b, the toner transferred onto the paper T is melted and fixed.

  A belt cleaning device 40 for cleaning the intermediate transfer belt 7 is disposed between the secondary transfer roller 8 and the tension roller 36. The belt cleaning device 40 includes a cleaning brush 41 that is in sliding contact with the surface of the intermediate transfer belt 7, a cleaning roller 42 that is disposed so as to be in contact with the cleaning brush 41, and a tip that is in contact with the surface of the cleaning roller 42. The blade 43 is disposed, and the recovery spiral 44 is disposed below the blade 43.

  On the lower side of the apparatus main body M, a paper feed cassette 52 that accommodates the paper T is arranged so that it can be pulled out in the horizontal direction. In the paper feed cassette 52, paper T is stored in a stacked state. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. The paper T placed on the placement plate is sent out to the transport path 54 by the cassette paper feed unit 51 disposed at the paper feed side end of the paper feed cassette 52 (right end in FIG. 1). The cassette paper feed unit 51 includes a double feed prevention mechanism including a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 63 for feeding the paper T one by one to the transport path 54. Prepare.

A conveyance path 54 for conveying the paper T is formed between the cassette paper feeding unit 51 and the paper discharge unit 50. The conveyance path 54 includes a first conveyance path 55 from the cassette paper feeding unit 51 to the secondary transfer roller 8, a second conveyance path 56 from the secondary transfer roller 8 to the fixing device 9, and a discharge unit from the fixing device 9. Up to 50 external discharge conveyance paths 510. The out-of-machine discharge conveyance path 510 constitutes a part of a conveyance discharge reversing unit 500 described later. Further, a return conveyance path 59 for returning the paper T to the first conveyance path 55 is formed between the conveyance discharge reversing unit 500 and a curved path 55 a described later in the first conveyance path 55.
Details of the transport discharge reversing unit 500 will be described later.

  The first conveyance path 55 conveys the paper T fed from the paper feed cassette 52 upward, while turning the conveyance direction to the left in FIG. 1 and the curved path 55a to the secondary transfer roller 8. Straight path 55b. In the first conveyance path 55, a guide plate and a roller pair that convey the paper T while guiding it are arranged. Further, a sensor for detecting the paper T and a registration roller pair 80 for adjusting the skew (oblique paper feeding) of the paper T and the timing of the toner image are arranged in the first transport path 55. The sensor is disposed immediately before (on the upstream side) the registration roller pair 80 in the transport direction of the paper T. The registration roller pair 80 conveys the paper T by performing the above-described correction and timing adjustment based on the detection signal information from the sensor.

  The second transport path 56 is a linear transport path that is inclined downward toward the fixing device 9 side. A transport belt 156 that transports the paper T in a state where the paper T is placed is disposed in the second transport path 56. A sensor for detecting the paper T is disposed at a predetermined position in the second transport path 56.

  The return conveyance path 59 is formed so as to pass from the conveyance discharge / reversal unit 500 to the fixing device 9, the second conveyance path 56, the secondary transfer roller 8, and the registration roller pair 80, and further upward. The return conveyance path 59 is formed so as to merge with the curved path 55 a in the first conveyance path 55. The return conveyance path 59 is a conveyance path for returning the paper T that has passed through the fixing device 9 to the upstream side of the registration roller pair 80 disposed on the upstream side of the secondary transfer roller 8. The return conveyance path 59 is a conveyance path that is used when performing so-called double-sided printing (printing) in which toner images (including characters and the like) are printed (printed) on both sides of the paper T. For example, the paper T is returned to the first transport path 55 via the return transport path 59 in a state where the front and back are reversed by the transport discharge reversing unit 500. Like the other transport paths, the return transport path 59 has a guide plate and a pair of rollers that transport the paper T while guiding it, and a sheet detection sensor is disposed at a predetermined position.

  A manual paper feed section 64 is provided on the right side surface of the apparatus main body M in FIG. The manual paper feed unit 64 includes a manual feed tray 65 that forms a side wall in the closed state, and a paper feed roller 66. The manual feed tray 65 is attached to the vicinity of the curved path 55a of the first transport path 55 so that the lower end of the manual feed tray 65 can rotate (open and close). The manual paper feed unit 64 feeds the paper T placed on the open manual feed tray 65 to the curved path 55 a of the first transport path 55.

  Next, the transport discharge reversing unit 500 will be described in detail. FIG. 2 is a schematic diagram showing the transport discharge reversing unit 500 in the apparatus main body M. FIG. 3 is a perspective view showing the conveyance path switching means 540. FIG. 4 is a perspective view partially showing the merging conveyance path 530. FIG. 5A is a diagram illustrating a state in which the paper T is transported through the confluence transport path 530, and FIG. 5B is a cross-sectional view taken along line BB illustrated in FIG.

  As shown in FIGS. 1 and 2, the transport discharge reversing unit 500 is provided between the fixing device 9 and the paper discharge unit 50, and transports the paper T discharged from the fixing device 9 to the paper discharge unit 50. When the paper is discharged from the paper discharge unit 50 and duplex printing is performed, the unit reverses the front and back surfaces of the paper T. The transport discharge reversing unit 500 includes an out-of-machine discharge transport path 510, a reversal transport path 520, a merging transport path 530, an air supply unit 551, a transport path switching unit 540, and an exhaust unit 552. The transport discharge reversing unit 500 includes a switchback roller pair 601, a turning roller 600, a communication transport path 610, and a second transport path switching unit 602.

  The external discharge conveyance path 510 is a conveyance path for discharging the paper T discharged from the fixing device 9 from the paper discharge unit 50 to the outside of the housing M1. The out-of-machine discharge conveyance path 510 is configured to include a guide plate including an out-of-machine discharge conveyance path forming member 511 and a roller pair 591, 592, 593 that conveys the paper T while guiding the paper T, and is provided at a predetermined position. A paper detection sensor (not shown) is disposed. The out-of-machine discharge conveyance path forming member 511 is a guide plate facing an air supply means 551 (details will be described later). The out-of-machine discharge conveyance path forming member 511 has an opening 512 above the conveyance path switching means 540. An opening 513 is provided in an area where the conveyance path switching means 540 is not substantially provided.

The reversing conveyance path 520 is a conveyance path for inverting the front and back surfaces of the paper T branched from the outside discharge conveyance path 510 and discharged from the fixing device 9. A branch portion where the reversal conveyance path 520 branches from the out-of-machine discharge conveyance path 510 is referred to as a first branch section 501. The reversing conveyance path 520 extends substantially downward from the first branch portion 501. The reversing conveyance path 520 includes a guide plate including a pair of opposing reversing conveyance path forming members 521 and 522 and a pair of rollers 594 and 595 that conveys the paper T while guiding the paper T, and has a predetermined position. Is provided with a sensor (not shown) for paper detection.
The reversing transport path forming member 521 located on the confluence transport path 530 (details will be described later) is provided with a first ventilation opening 560.

The confluence conveyance path 530 is a conveyance path that joins the paper T that has passed through the reversal conveyance path 520 to the out-of-machine discharge conveyance path 510. A joining part where the joining transport path 530 joins the outside discharge transport path 510 is referred to as a first joining part 502. The first junction unit 502 is located on the downstream side of the first branching unit 501 in the outside discharge conveyance path 510. The joining conveyance path 530 extends substantially upward toward the first joining unit 502. The confluence conveyance path 530 includes a guide plate and a roller pair 596 including a pair of confluence conveyance path forming members 531 and 532 facing each other, and a sheet detection sensor (not shown) at a predetermined position. ) Is arranged.
The opposite merging conveyance path forming members 531 and 532 are provided with a second ventilation opening 570 and a third ventilation opening 580, respectively.

In this specification, the conveyance direction of the paper T is referred to as “first direction D1”, and the opposing direction of the pair of confluence conveyance path forming members 531 and 532 is referred to as “second direction D2”, and the first direction D1. A direction orthogonal to the second direction D2 is referred to as a “third direction D3”.
As shown in FIGS. 4 and 5, the second ventilation opening 570 and the third ventilation opening 580 are each composed of a plurality of long holes 571 and 581. The plurality of long holes 571 and 581 extend so as to expand in the third direction D3 in the first direction D1. That is, the plurality of long holes 571 and 581 extend in a “C” shape. The plurality of long holes 571 and 581 extending in the same direction extend in parallel, and have a shape in which a part thereof overlaps when viewed in the first direction D1.

  The second ventilation opening 570 and the third ventilation opening 580 substantially overlap when viewed in the direction from the second ventilation opening 570 toward the exhaust means 552 (second direction D2 in this embodiment). ing. “Substantially overlap” means that the area of the overlapping region is 90% or more of the area of the second ventilation opening 570.

  The air supply unit 551 is a unit that blows air A toward the reversing conveyance path 520, and includes, for example, a fan. The air supply means 551 is provided on the side opposite to the reversing conveyance path 520 (on the reversing conveyance path forming member 522 side) with respect to the first branch portion 501. The air supply means 551 is opposed to the openings 512 and 513 in the reversing conveyance path forming member 522.

  The transport path switching unit 540 is a unit that is provided in the first branching unit 501 and switches the transport destination of the paper T to the out-of-machine discharge transport path 510 or the reverse transport path 520. As shown in FIG. 3, the transport path switching unit 540 is configured by connecting a large number of wedge-shaped wedge-shaped pieces 543 arranged in parallel at predetermined intervals to a swing shaft 541. The front end side of the wedge-shaped piece 543 is further connected by a support shaft 542. The transport path switching unit 540 is configured to be swingable about the swing shaft 541, so that the transport destination of the paper T can be switched to the out-of-machine discharge transport path 510 or the reverse transport path 520.

The conveyance path switching unit 540 includes an air passage unit 544 that allows the air A blown from the air supply unit 551 to pass therethrough. That is, the space between the wedge-shaped pieces 543 and 543 adjacent in the axial direction of the swing shaft 541 becomes the air passage portion 544.
In the present embodiment, the air A that has passed through the air passage portion 544 is configured to be blown toward the image forming surface T3 (see FIG. 3) of the paper T. That is, air A is blown onto the image forming surface T <b> 3 via the air passage portion 544 of the transport path switching unit 540 on the paper T transported to the reverse transport path 520.

  The exhaust means 552 is provided between the housing M1 and the merging conveyance path 530. Specifically, the exhaust unit 552 faces the third ventilation opening 580 in the confluence conveyance path forming member 532. The exhaust unit 552 sucks the air A from the air supply unit 551 through the first ventilation opening 560, the second ventilation opening 570, and the third ventilation opening 580, and discharges the air A to the outside of the housing M1. Means, for example, a fan. Although not shown in FIG. 2, the housing M <b> 1 is provided with an opening for exhausting air A from the exhaust means 552.

  As shown in FIG. 5, the second ventilation opening 570 and the third ventilation opening 580 are such that the air A that has passed through the second ventilation opening 570 and the third ventilation opening 580 is in the first direction D1 on the paper T. It is comprised so that it may spray on the both ends T4 which follow.

  As shown in FIG. 1, the switchback roller pair 601 reverses the transport direction of the paper T transported from the reversing transport path 520. That is, the switchback roller pair 601 sandwiches the paper and switches it back.

  The turning roller 600 conveys the paper T switched back by the switchback roller pair 601 toward the merging conveyance path 530 or conveys it to the return conveyance path 59 by turning the conveyance direction by about 180 degrees.

The communication conveyance path 610 is a conveyance path that connects the switchback roller pair 601 and the turning roller 600.
The second transport path switching means 602 is provided at the terminal end of the communication transport path 610. This is means for switching the transport destination of the paper T that is switched back by the switchback roller pair 601 and transported through the communication transport path 610 to the confluence transport path 530 or the return transport path 59.

Next, the basic operation of the color copier 1 of this embodiment will be briefly described.
The image read from the document feeding unit 70 is read by the image reading unit 71. The image information in the read image is input to the apparatus main body M.

  The image information input to the apparatus main body M is input to an image formation control unit (not shown). Based on the image information, the image formation control unit includes the photosensitive drums 2a to 2d as the image carrier constituting the image forming unit, the charging units 10a to 10d, the laser scanner units 4a to 4d, the developing devices 16a to 16d, and the like. Control. A predetermined toner image is formed on the photosensitive drums 2a to 2d based on the image information (see FIG. 1).

  The toner images formed on the photosensitive drums 2a to 2d are secondarily transferred onto the paper T at the secondary transfer nip N2 via the intermediate transfer belt 7. The paper T on which the image is formed is discharged from the paper discharge unit 50 to the outside of the housing M1 (see FIG. 1).

Here, when the paper T is printed on one side, in the transport discharge reversing unit 500, the paper T is discharged directly (without passing through the reversing transport path 520) via the external discharge transport path 510. It is discharged from the portion 50 to the outside of the housing M1.
On the other hand, when the paper T is printed on both sides, the paper T is turned upside down through the reversing conveyance path 520, the switchback roller pair 601, the turning roller 600, the return conveyance path 59, and the like. The sheet is conveyed again to the next transfer nip N2, and printing (image formation) on the back surface of the paper T is performed. Further, the paper T printed on the back surface is reversed again and again (without printing) through the reversing conveyance path 520, the switchback roller pair 601, the merging conveyance path 530, and the like. The paper is discharged from the paper discharge unit 50 to the outside of the housing M1.

According to the color copier 1 of the present embodiment having the above configuration, the following effects are exhibited.
As shown in FIG. 2, the color copying machine 1 according to the present embodiment forms the first ventilation opening 560 provided in the reversing conveyance path forming member 521 that forms the reversing conveyance path 520 and the merging conveyance path 530. Provided between the second ventilation opening 570 and the third ventilation opening 580 provided in the pair of opposing confluence conveyance path forming members 531 and 532, and the housing M1 and the confluence conveyance path 530, respectively. An exhaust means 552 that sucks air A from the air supply means 551 and discharges it to the outside of the housing M1 through the first ventilation opening 560, the second ventilation opening 570, and the third ventilation opening 580. Prepare.

  Therefore, the air A blown from the air supply means 551 is promptly discharged to the outside of the housing M1 by the exhaust means 552 via the first ventilation opening 560, the second ventilation opening 570, and the third ventilation opening 580. Discharged. Thus, since the hot air (air A) inside the housing M1 (especially inside the reversing conveyance path 520) is quickly discharged to the outside of the housing M1, the cooling of the paper T by the air feeding means 551 is performed. The effect can be sufficiently achieved.

  As shown in FIGS. 3 to 5, the color copier 1 of the present embodiment is configured such that the air A that has passed through the air passage portion 544 is blown toward the image forming surface T3 side of the paper T. Therefore, the image forming surface T3 side of the paper T can be efficiently cooled, and the image forming surface T3 of the paper T is difficult to contact the transport path switching unit 540 and the like, and the image formed on the paper T is damaged. Hateful.

  As shown in FIGS. 4 and 5, in the present embodiment, the second ventilation opening 570 and the third ventilation opening 580 are each composed of a plurality of long holes 571 and 581, and a plurality of long holes 571. And 581 extend so as to expand in the third direction D3 toward the first direction D1. Therefore, the air A blown from the second ventilation opening 570 toward the third ventilation opening 580 is widely blown against the paper T in the third direction D3, and is conveyed through the merging conveyance path 530. The paper T is easily conveyed in a spread state. Therefore, it is possible to prevent the sheet T from being caught by the second ventilation opening 570 from the second ventilation opening 570 and hindering its conveyance.

  As shown in FIGS. 4 and 5, in the present embodiment, the second ventilation opening 570 and the third ventilation opening 580 are viewed from the second ventilation opening 570 toward the exhaust unit 552. The case is substantially overlapping. Therefore, the air A flowing into the confluence conveyance path 530 from the second ventilation opening 570 is easily discharged smoothly from the third ventilation opening 580, and thus is easily discharged outside the housing M1.

  As shown in FIGS. 4 and 5, in the present embodiment, the second ventilation opening 570 and the third ventilation opening 580 are air that has passed through the second ventilation opening 570 and the third ventilation opening 580. A is configured to be sprayed to both ends T4 of the paper T along the first direction D1. Therefore, both end portions T4 of the paper T are easy to spread, and the transportability of the paper T is further improved.

As mentioned above, although preferred embodiment was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above.
For example, the configurations (particularly the shape and number) of the first ventilation opening 560, the second ventilation opening 570, and the third ventilation opening 580 are not particularly limited. Further, the configuration of the conveyance path switching means 540 (particularly the shape and number of the air passage portions 544) is not particularly limited.

In this embodiment, an image is formed on the paper T. However, the image forming apparatus of the present invention can form an image on a transfer material other than the paper T, for example, a film sheet.
In this embodiment, the color copying machine 1 is described as an image forming apparatus. However, the image forming apparatus is not limited to this, and may be a monochrome copying machine, a printer, a facsimile machine, or a multifunction machine thereof.

2 is a left side view for explaining the arrangement of each component in the color copier 1. FIG. FIG. 3 is a schematic diagram showing a transport discharge reversing unit 500 in the apparatus main body M. FIG. 6 is a perspective view showing a conveyance path switching unit 540. It is a perspective view which shows the conveyance path for merge 530 partially. (A) is a figure which shows the state in which the paper T is conveyed by the conveyance path 530 for confluence | merging, (b) is a BB sectional drawing shown to (a).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Color copier (image forming apparatus), 9 ... Fixing device (fixing part), 501 ... 1st branch part, 510 ... Out-of-machine discharge conveyance path, 520 ... Reverse conveyance path, 521 ... Reversing transport path forming member, 530... Confluence transport path, 531, 532... Converging transport path forming member, 540... Transport path switching means, 544. ...... Exhaust means, 560... 1st ventilation opening, 570... 2nd ventilation opening, 571, 581... Slot, 580... 3rd ventilation opening, D1. Second direction, D3 ... Third direction, M1 ... Housing, T ... Paper (transferred material)

Claims (5)

A housing,
An image forming unit for forming an image on a sheet-like transfer material;
A fixing unit for fixing the image formed on the transfer material by the image forming unit to the transfer material;
An out-of-machine discharge conveyance path for discharging the material to be transferred discharged from the fixing unit to the outside of the housing;
A reversing conveyance path for reversing the front and back surfaces of the material to be transferred, branched from the outside discharge conveying path and discharged from the fixing unit;
A merging conveyance path for merging the material to be transferred via the reversing conveyance path with the discharge discharge conveyance path;
An air supply means provided on a side opposite to the reversing conveyance path with respect to the first branch portion where the reversing conveyance path branches from the out-of-machine discharge conveyance path, and for blowing air toward the reversing conveyance path; ,
A conveyance path that is provided in the first branching section and has an air passage section that allows the air blown from the air feeding means to pass therethrough, and switches the conveyance destination of the transfer material to the outside discharge conveyance path or the reversal conveyance path. Switching means;
A first ventilation opening provided in a reversing conveyance path forming member that forms the reversing conveyance path;
A second ventilation opening and a third ventilation opening respectively provided in a pair of opposing merging conveyance path forming members forming the merging conveyance path;
Air is provided between the housing and the merging conveyance path, and sucks air from the air feeding means through the first ventilation opening, the second ventilation opening, and the third ventilation opening. And an exhaust unit that discharges the outside of the housing.   The image forming apparatus according to claim 1, wherein the air that has passed through the air passage portion is configured to be blown toward an image forming surface side of a transfer material.   Each of the second ventilation opening and the third ventilation opening is composed of a plurality of long holes, and the plurality of long holes move in the first direction and the first direction as the transfer material is conveyed. 3. The image forming apparatus according to claim 1, wherein the image forming apparatus extends in a third direction that is a direction orthogonal to a second direction that is a facing direction of the pair of confluence conveyance path forming members.   The image forming apparatus according to claim 3, wherein the second ventilation opening and the third ventilation opening substantially overlap when viewed in a direction from the second ventilation opening toward the exhaust unit.   The second ventilation opening and the third ventilation opening are configured so that the air that has passed through the second ventilation opening and the third ventilation opening is blown to both ends of the transfer material along the first direction. The image forming apparatus according to claim 3 or 4, wherein the image forming apparatus is configured.

Images