JP4463258B2 - Double-sided apparatus and image forming apparatus - Google Patents

Description

The present invention relates to a double-sided device used when forming images on both sides of a first side and a second side of a sheet, and an image forming apparatus including the double-sided device.

As an image forming apparatus having a double-sided device that can form images on both sides of a conventional sheet, for example, there is one described in Patent Document 1.
As shown in FIG. 12, the image forming apparatus (double-sided printing apparatus) includes a reversing unit 60 that is used for reversing the paper when the image (toner image) is formed on both sides of the paper. It is mounted over the front surface (the right surface in FIG. 12).
In addition, a manual guide 51 used for manual paper feeding is provided on the front surface of the apparatus so as to be openable and closable.
JP-A-6-110274

In this image forming apparatus, in the duplex printing mode in which images are formed on both sides of a sheet, the sheet is fed from the sheet cassette 52, and is temporarily stopped by the registration roller 61 and the timing is adjusted. Is transported toward the process unit 50 in which is provided.
When the paper is supplied from the manual feed guide 51, the paper is conveyed toward the process unit 50 through the manual feed path 58.

In this way, the paper fed from the paper cassette 52 or the manual feed guide 51 is transferred with the process unit 50 onto the front side (first side) of the toner image, and the toner image is heat-fixed by the heat fixing unit. The
Then, the sheet is conveyed upward in FIG. 12, and when the sensor 54 detects the leading edge, the switching lever 55 is rotated to the position indicated by the solid line in FIG. 12, and the sheet is guided into the reversing unit 60. become.

  As a result, the sheet is conveyed by the rotation of the pair of switchback rollers 56, and the leading end thereof jumps out onto the stacker 65. Then, when the sensor 57 detects the trailing edge of the paper, the pair of switchback rollers 56 rotates in reverse.

As a result, the paper is now conveyed toward the outlet 62 through the conveyance path 63 in the reversing unit 60, with the trailing edge until then being the leading edge. The sheet is conveyed toward the process unit 50 through the manual feed path 58, and the process unit 50 forms a toner image on the back surface.
Then, the sheet is guided to the pair of discharge rollers 59 by the switching lever 55 already switched to the position indicated by the phantom line in FIG. 12, and is discharged onto the stacker 65 by the conveying force of the discharge roller 59.

  However, in the configuration in which the reversing unit 60 that functions as a double-sided device used when forming an image on both sides of a sheet is mounted from the top to the front of the device like this image forming device, for example, on the front side surface When the paper on which the image has been formed becomes jammed while passing through the switching lever 55 to form an image on the back side, the front side (right side in FIG. 12) of the apparatus is opened to work. However, the reversing unit 60 sometimes gets in the way.

Similarly, the reversing unit 60 sometimes gets in the way when replacing supplies.
On the other hand, there are image forming apparatuses in which a double-sided device provided with a reversing mechanism or the like is disposed below the main body of the apparatus. However, when the paper becomes jammed in the double-sided device, the jam is also detected. Processing was troublesome.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a double-sided device that can easily perform the jam processing even when the paper is jammed in the double-sided device. .

In order to achieve the above-described object, the present invention provides a drawer tray having a casing portion fixed to the apparatus main body, and a reversing mechanism that can be pulled out forward of the apparatus main body with respect to the casing section and reverses the paper. The double-sided device including the unit is configured as follows.
A tray part pull-out amount restricting means for restricting a pull-out amount of the drawer tray part toward the front of the apparatus main body with respect to the housing part in a plurality of stages;
The paper transport system of the drawer tray section includes a pair of guide plates that are vertically opposed to each other, and the pair of guide plates transports the paper in the same number as the number of drawer stages of the drawer tray section regulated by the tray section drawer amount regulating means. Each of the paired guide plates of each of the divided pairs is provided so as to be openable with respect to the guide plate located on the lower side .
Each pair of divided guide plates is spaced apart in the pull-out direction of the drawer tray, and a fixed guide plate is provided in the spaced-apart portion, and there is paper in the fixed guide plate portion. Ru provided a detection means for detecting.
More specifically, the double-sided device is used by being attached to the apparatus main body, and when forming an image on both the first side and the second side of the paper, the paper on which the image is formed on the first side is turned upside down. This is a double-sided apparatus that re-feeds to form an image on the second side, and may be configured as follows.

  A paper discharge double-sided conveyance unit provided with a conveyance path switching unit that switches a conveyance direction between a direction in which a sheet after an image is formed on the first surface is discharged to the outside of the apparatus and a direction in which the sheet is re-feeded; The vertical conveyance unit that conveys the paper guided in the refeeding direction by the conveyance path switching means toward the lower side of the apparatus, and the paper conveyed through the vertical conveyance unit is received and the front and back are reversed by the reversing mechanism. The reversing unit refeeds the paper to form an image on the second surface.

  The reversing portion is provided with a housing portion and a drawer tray portion that can be pulled out forward of the apparatus main body with respect to the housing portion, and the reversing mechanism and the reversing mechanism are disposed on the drawer tray portion. A double-sided apparatus is configured by providing a paper transport system for transporting paper and a paper re-feeding mechanism that feeds the paper whose front and back are reversed by the reversing mechanism to form an image on the second surface.

Further, there is provided a tray part pull-out amount restricting means for restricting the pull-out amount of the drawer tray part toward the front of the apparatus main body in a plurality of stages, and the sheet conveying system of the drawer tray part is a pair of guide plates facing vertically. The pair of guide plates are provided in the paper transport direction divided into the same number as the number of drawer stages of the drawer tray section regulated by the tray section drawer amount regulating means, and each of the divided pair of guide plates is provided. Each guide plate positioned at least on the upper side of the guide plate is supported so as to be openable with respect to the guide plate positioned on the lower side ,
Each pair of divided guide plates is spaced apart in the pull-out direction of the drawer tray, and a fixed guide plate is provided in the spaced-apart portion, and there is paper in the fixed guide plate portion. Ru provided a detection means for detecting.

Each guide plate that can be opened preferably supports the rear end side of the drawer tray portion in the drawer direction so as to be rotatable.
Further, the number of divisions of the pair of guide plates is set to two for the upper and lower guide plates, and the divided upper and lower guide plates are formed of the same parts, and the divided pair of guides are formed. The same sheet conveying roller may be attached to each plate.

An image forming apparatus according to the present invention includes any one of the above-described double-sided devices.

According to the double-sided apparatus and the image forming apparatus including the same according to the present invention, the following effects can be obtained.
Since the double-sided device includes a casing unit fixed to the apparatus main body and a drawer tray unit that can be pulled out of the casing unit and has a reversing mechanism that reverses the paper, Even if a jam occurs in the transport path, the jam processing can be performed with the drawer tray portion being pulled out from the apparatus main body. Therefore, it is possible to improve the jam handling property and the maintenance property.
Further, the amount of drawer of the apparatus main body with respect to the casing portion of the drawer tray portion can be performed in a plurality of stages, and each guide plate disposed in a divided state is opened for each drawer stage. Therefore, it is possible to perform jam processing while adjusting the pull-out amount of the drawer tray portion depending on the location where the jam occurs, so that the jam processing performance can be improved.
Further, each of the pair of guide plates divided into a plurality is arranged with a gap in the pull-out direction of the drawer tray portion, and a fixed guide plate is provided at the gap, and the fixed guide plate portion Since the detecting means for detecting the presence or absence of paper is provided in the case, even if the guide plate is opened when a jam occurs, the user can be prevented from touching the detecting means at that time.

Also, each divided openable each guide plates, if each rotatably supported in drawing direction of the rear end of the drawer tray, improvement in operability by reducing the opening operation of the respective guide plates Even if it aims at, it can improve the visibility of jam paper.
The division number of the pair of guide plates vertically together with the two, if they to use those also paper transporting rollers of the same as well as to the same parts, reduction of parts cost due to increase in the lot, parts fabrication steps Therefore, the cost of the mold can be reduced, so that the cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram showing an example of a color image forming apparatus provided with another double-sided device corresponding to the double- sided device according to the present invention.

  The color image forming apparatus shown in FIG. 1 is used by being attached to the apparatus main body 1. When forming images on both the first surface on the front surface side and the second surface on the back surface side of the sheet, the color image forming device is formed on the first surface. The paper after the toner image (image) is formed from the intermediate transfer belt 10 and fixed by the fixing device 3 is re-fed toward the intermediate transfer belt 10 in order to reverse the paper and form an image on the second surface. A double-sided device 5 is provided.

The color image forming apparatus is provided with a pair of paper discharge rollers 21 that discharge paper to the paper discharge stack unit 22 by conveying paper toward the back of the apparatus main body 1 at the top of the apparatus main body 1.
The double-sided device 5 has a switching claw 23 that functions as a conveyance path switching unit that switches a conveyance direction between a direction in which a sheet on which an image is formed on the first surface is discharged to the outside and a direction in which the sheet is re-feeded. A paper discharge double-sided conveyance unit 30, a vertical conveyance unit 32 that conveys a sheet guided in the direction of refeeding by the switching claw 23, and a sheet conveyed through the vertical conveyance unit 32. And a reversing unit 33 which reverses the front and back surfaces by a reversing mechanism including a reversing roller 31 and a reversing guide plate 36, and refeeds the paper to form an image on the second surface.

The paper discharge double-sided conveyance unit 30 is provided outside the upper surface of the apparatus main body 1 and adjacent to the paper discharge unit having the paper discharge roller pair 21, and includes the switching claw 23 and the double-sided conveyance path 41 described above. Yes.
The vertical conveyance unit 32 is provided outside the back surface of the apparatus main body 1 and conveys the sheet conveyed to the double-sided conveyance path 41 toward the lower side of the apparatus.

  The reversing unit 33 is provided outside the lower surface of the apparatus main body 1, accepts a sheet conveyed through the vertical conveyance unit 32, and conveys the sheet toward the front (right side in FIG. 1) of the apparatus main body 1. The front and back are reversed with the reverse guide plate 36, the paper is switched back, and the paper is fed again toward the image forming unit with the intermediate transfer belt 10.

The reversing unit 33 is provided with a pair of jogger fences 48 that align the positions of both side edges with respect to the sheet conveyance direction of the sheet conveyed on the tray 37 with the front and back reversed.
The sheet discharge duplex conveyance unit 30, the vertical conveyance unit 32, and the reversing unit 33 are each formed in a unit shape that can be attached to and detached from the apparatus main body 1.

  This color image forming apparatus includes a photosensitive belt 2 that is a belt-shaped image carrier having flexibility in an image forming portion, and four colors (three colors) that are sequentially formed on the surface of the photosensitive belt 2. It is a rotary type that is integrally provided with four developing devices for developing the latent images corresponding to the respective colors separated into four (4) toners (developers) of yellow, magenta, cyan, and black. A color developing device 4 is provided.

The intermediate transfer belt 10 is rotatable in the direction indicated by the arrow B in FIG. 1 and carries the toner images of a plurality of colors developed by the developing device 4 in a state where the toner images are sequentially superimposed.
The intermediate transfer belt 10 is installed between the rotation rollers 12 and 13 and is rotated in the direction indicated by the arrow B by the rotation of the rotation roller 12. The intermediate transfer belt 10 is in contact with the photosensitive belt 2 and the rotating roller 7.

A conductive bias roller 14 is in contact with the inner surface of the intermediate transfer belt 10 near the contact portion under a predetermined condition. Further, a transfer roller 15 is brought into contact with a portion corresponding to a position of the rotation roller 12 on the outer surface of the intermediate transfer belt 10.
The photosensitive belt 2 is installed between the rotation rollers 6 and 7, and is rotated in the direction indicated by the arrow A (clockwise direction in the drawing) by the rotation of the rotation roller 6.

A charging charger 8 that functions as charging means for uniformly charging the surface of the photosensitive belt 2 is provided below the photosensitive belt 2, and laser writing that functions as electrostatic image exposure means is provided below the charging belt 8. On the lower side of the unit 9, a paper feed cassette 11 serving as a paper stacking unit for storing paper P to be fed is provided.
As described above, in this color image forming apparatus, the paper feed cassette 11 that stores the paper P in the lower part of the apparatus main body 1 is provided close to the reversing unit 33 of the double-sided device 5 and directly above the reversing unit 33. ing.

A paper feed roller 18 is provided on the paper delivery end side (right side in FIG. 1) of the paper feed cassette 11, and the paper P in the paper feed cassette 11 can be fed by the paper feed roller 18.
A vertical conveyance path 45 that extends in the vertical direction and joins a conveyance path 43 that conveys the sheet P fed from the sheet cassette 11 is provided on the sheet delivery end side of the sheet cassette 11.
On the paper transport path from the paper feed cassette 11 to the transfer position where the transfer roller 15 is located, a transport roller pair 19 and a registration roller pair 20 are provided.

In addition to the switching claw 23 and the double-sided conveyance path 41 described above, the paper discharge double-sided conveyance unit 30 of the double-sided device 5 also includes a paper discharge roller pair 27 in the paper discharge unit.
Thereby, the paper discharge roller pair 21, the switching claw 23, and the paper discharge roller pair 27 in the paper discharge unit can discharge the paper after the image formation to the paper discharge stack unit 22 provided outside the apparatus main body 1. ing.

Further, this color image forming apparatus is provided with an operation unit for performing various operations on the front surface (right surface in FIG. 1) upper portion 1a of the apparatus main body 1.
The apparatus main body 1 is composed of a main body frame 24 on the non-moving part casing side and a front frame 25 serving as a front casing capable of opening the paper transport path.

The front frame 25 is supported so as to be openable in the direction indicated by the arrow C around a rotation support shaft 26 provided on the main body frame 24, and is closed and used as shown in FIG.
At the time of paper jam processing, when the front frame 25 is opened in the direction of arrow C, the open state can be maintained by a tension spring or the like (not shown).

The front frame 25 is provided with one guide plate constituting the paper conveyance path, and a registration roller pair 20 provided on the paper conveyance path, a transfer roller 15 and the like are attached.
As a result, when the front frame 25 is opened, the paper transport path is divided into two, so that if there is a jammed paper, it can be easily removed.

  In this way, this color image forming apparatus is configured, and the sheet conveyance path of the duplex apparatus 5 proceeds from the switching claw 23 of the sheet discharge duplex conveyance section 30 to the rear of the apparatus body 1 and the rear surface of the apparatus body 1. Is routed downward by the vertical conveying unit 32 to reach the reversing unit 33 at the bottom of the apparatus body 1, and the sheet is transferred from the reversing unit 33 to the transfer position where the intermediate transfer belt 10 and the transfer roller 15 are provided. The paper can be fed again.

Next, an image forming operation of this color image forming apparatus will be described.
When the color image forming apparatus shown in FIG. 1 starts an image forming operation, the surface of the photosensitive belt 2 is uniformly charged by the charging charger 8 and then the charged surface is converted into image information by the laser writing unit 9. Based on the scanning exposure, an electrostatic latent image is formed there.

  Here, the image information to be exposed is single-color image information obtained by separating the full-color image to be formed into each color information of yellow, cyan, magenta, and black, and is emitted from the semiconductor laser of the laser writing unit 9 according to the information. The laser beam is scanned and adjusted by an optical device.

Then, the electrostatic latent images sequentially formed corresponding to the respective colors on the photosensitive belt 2 are developed in a single color with yellow, cyan, magenta and black toners by the rotary developing device 4, respectively. Each color image is sequentially formed on the belt 2.
Each single-color image formed on the photosensitive belt 2 moves to the position in contact with the intermediate transfer belt 10 by rotating the photosensitive belt 2 in the direction indicated by the arrow A. A predetermined transfer bias is applied to the bias roller 14 for each magenta and black monochrome image, and the images are sequentially superimposed and transferred onto the intermediate transfer belt 10.

The four color images superimposed on the intermediate transfer belt 10 are fed from the paper feed cassette 11 by the paper feed roller 18 at a predetermined timing, and are conveyed to the transfer section through the conveyance roller pair 19 and the registration roller pair 20. The transfer roller 15 collectively transfers the sheet P to be transferred.
Then, the sheet P on which the color image is transferred is conveyed to the fixing device 3 and the toner image is fixed. When a full-color image is formed only on one side, the paper is discharged from the paper discharge roller pair 21 directly through the switching claw 23 onto the paper discharge stack unit 22 by the paper discharge roller pair 27 in the paper discharge unit.

  Further, when full-color images are formed on both sides of the paper, basically the same operation as that for forming a full-color image on one side of the paper described above is performed. Therefore, the sheet on which the full-color image is formed only on one side conveyed by the discharge roller pair 21 is guided by the switching claw 23 and is placed below the discharge stack unit 22. The paper is fed into the double-sided conveyance path 41 in the paper discharge double-sided conveyance unit 30, and is conveyed toward the vertical conveyance unit 32.

  The sheet conveyed to the vertical conveying unit 32 is provided there, and is conveyed to a reversing unit 33 provided with a plurality of pairs of sheet conveying rollers 35, which will be described in detail later. The sheet sent to the reversing unit 33 is conveyed from the rear of the apparatus toward the front (operator side) by a plurality of sheet conveying rollers 35 in a conveying path 34 formed by upper and lower guide plates 46 and 47. The direction is changed by the reversing roller 31 while being guided by the reversing guide plate 36, and the front and the back are reversed and conveyed on the tray 37.

The paper is aligned at both side edges by a pair of jogger fences 48, and the reverse roller 31 rotates in reverse, so that the end on the side which has been the rear end until now becomes the front end, and this is the switchback conveyance. The paper is re-feeded and conveyed toward a pair of delivery conveyance rollers 38 that function as a mechanism that changes the traveling direction in the reverse direction and feeds it.
The sheet is conveyed again to the conveyance roller pair 19 and the registration roller pair 20, and thereafter, an image is formed on the second surface through the same process as the image formation on the first surface.
Then, when the paper passes the paper discharge roller pair 21, it is guided to the switching claw 23 which is switched to the position indicated by the solid line in FIG. 22 is discharged.

By the way, in this color image forming apparatus, the reversing unit 33 of the double-sided device 5 is provided with a casing 16 fixed to the apparatus main body 1 and the front of the apparatus main body 1 with respect to the casing 16 (rightward in FIG. 1). And a drawer tray portion 17 that can be pulled out.
The drawer tray 17 has a reversing roller 31 and a reversing guide plate 36 that constitute a reversing mechanism, upper and lower guide plates 46 and 47 that serve as a sheet conveying system for conveying the sheet toward the reversing mechanism, and a plurality of sheets. A conveyance roller 35, a tray 37, and a pair of jogger fences 48 are also provided.

As shown in FIG. 2, guide rail portions 73 and 74 used when pulling out the drawer tray portion 17 are formed at both ends of the lower portion of the housing portion 16, for example, a frame in which the housing portion 16 is formed of resin. And is integrally formed.
Then, both side ends of the bottom portion of the drawer tray portion 17 are slidably mounted in the direction of arrow E on the guide rail portions 73 and 74 on both sides thereof. It can be pulled out and inserted.

A slip-off preventing stopper 75 that prevents the drawer tray portion 17 from coming out of the housing portion 16 is provided at the entrance portion of the housing portion 16 where the drawer tray portion 17 enters and exits.
The stopper 75, as shown in FIG. 3, is formed, for example, by bending a plate material into a U-shape, and has a through hole 75a in the front flat plate portion and a screw hole 75b in the rear flat plate portion. Are formed.

In addition, a long hole 76 is formed in the entrance portion of the housing portion 16 so as to correspond to the stopper 75 and to prevent the stopper 75 from being moved in the vertical direction. ing.
Then, in a state where the stopper 75 is positioned so that the through hole 75a is positioned in the long hole 76, a screw 77 is inserted into the through hole 75a and the long hole 76, and the screw 77 is screwed into the screw hole 75b. I wear it.

As a result, the removal prevention stopper 75 moves up and down within a range in which the screw 77 can move in the long hole 76 of the housing portion 16.
In this embodiment, the gap between the flat plate parts before and after the stopper stopper 75 is set to a predetermined size so that the stopper stopper 75 moves downward as shown by a solid line in FIG. The first position, which is the moved position, and the second position, which is the position moved upward as indicated by the phantom line, are held by the frictional force with the casing 16, respectively.

Then, when the screw 77 is loosened, the drop prevention stopper 75 moves to the lower first position due to its own weight. Therefore, in the normal state in which the screw 77 is loosened, the drop prevention stopper 75 is in the first position due to its own weight.
The stopper 75 is provided with a leaf spring or the like attached to the stopper 75 or the housing portion 16, and the stopper 75 is caused by frictional force by the spring force of the leaf spring or the like. It may be held at the second position.

On the other hand, as shown in FIG. 5, a protrusion 78 is formed at the rear end in the drawer direction of the drawer tray portion 17 so as to correspond to the removal prevention stopper 75 on the housing portion 16 side.
When the stopper 75 is in the first position moved downward as shown in FIG. 5, it comes into contact with the protrusion 78 formed at the rear end portion of the drawer tray portion 17 pulled out from the housing portion 16. In contact therewith, it functions to prevent the drawer tray portion 17 from coming out of the housing portion 16.
Accordingly, in this state, the drawer tray portion 17 cannot be pulled out any further.

Further, when the stopper 75 is at the second position where the stopper 75 is moved upward (the position indicated by the phantom line in FIG. 4), the drawer tray 17 is allowed to come out of the casing 16 and the drawer tray The part 17 can be inserted into the housing part 16.
In the state in which the stopper 75 is in the second position, even if the drawer tray portion 17 once pulled out and removed from the housing portion 16 is inserted into the housing portion 16 again, as shown in FIG. The upper end portion 17a of the drawer tray portion 17 comes into contact with the flat plate upper portion 75c on the front side of the removal preventing stopper 75 and cannot be pushed any further, and cannot be inserted to the predetermined insertion position shown in FIG.

Accordingly, in this state, the drawer tray portion 17 is incompletely attached to the housing portion 16.
Therefore, in this case, if the stopper stopper 75 is moved downward to the first position shown in FIG. 7, the upper end portion 17 a of the drawer tray portion 17 does not contact the flat plate upper portion 75 c of the stopper stopper 75. Therefore, it can be inserted to a predetermined insertion position.

  As described above, in this color image forming apparatus, the double-sided device 5 includes the paper discharge double-sided conveyance unit 30, the vertical conveyance unit 32, and the reversing unit 33 as described with reference to FIG. 16 and a drawer tray portion 17 that can be pulled out in the front direction of the apparatus main body 1 (rightward in FIG. 1) with respect to the casing portion 16.

  The drawer tray 17 is provided with a reversing mechanism as described above, a sheet conveying system including upper and lower guide plates 46 and 47 and a plurality of sheet conveying rollers 35 for conveying the sheet toward the reversing mechanism, Since the reversing roller 31 and the like constituting the paper feeding mechanism are provided, even if a jam occurs in the conveyance path 34 in the drawer tray portion 17, jam processing is performed with the drawer tray portion 17 being pulled out from the apparatus main body 1. This makes it possible to improve jam handling and maintainability.

In the double-sided device 5, the reversing mechanism and the refeeding mechanism are arranged on the leading end side (the right side in FIG. 1) in the pulling direction of the pulling tray unit 17, so that they are relatively jammed. The easy-to-use part is on the operator side, so jamming is easy.
Further, since the guide rail portions 73 and 74 used for pulling out the drawer tray portion 17 are integrally provided in the housing portion 16, the number of components can be reduced as compared with the case where they are formed as separate components. Can do.

  Furthermore, since the double-sided device 5 is provided with a stopper 76 that prevents the drawer tray 17 from coming out of the casing 16, the user accidentally pulled out the drawer tray 17 from the casing 16 by mistake. Even if the position of the stopper 75 is set at the first lower position in advance, the drawer tray portion 17 is safe because it does not fall out of the housing portion 16.

  Since the stopper 75 is capable of moving to the first position and the second position described above, the drawer tray portion 17 is attached to the housing portion 16 by switching the position as necessary. It is possible to prevent the removal preventing stopper 75 from interfering with the attachment / detachment of the drawer tray portion 17 with respect to the housing portion 16 during assembly or maintenance.

  Further, in this double-sided device 5, when the drawer tray portion 17 is inserted into the housing portion 16 with the stopper stopper 75 in the upper second position as described above, the drawer tray portion 17 is not Since the user contacts the stopper 75 without being inserted to the insertion position, the user immediately notices that the stopper 75 is forgotten to return.

  If the screw 77 is loosened, the stopper 75 will be at the lower first position that prevents the drawer tray 17 from coming out of the casing 16 due to its own weight. However, unless the stopper 75 is consciously moved to the second position on the upper side, the first position is set. Thereby, it is possible to prevent the user from forgetting to return to the first position while keeping the stopper 75 at the second position.

Figure 8 is a schematic view showing only inverting section of an embodiment of a double-sided device according to the invention, parts corresponding to those in FIG. 1 are denoted by the same reference numerals.
The double-side unit, only double-side unit 5 and the inverting configuration of a color image forming apparatus shown in FIG. 1 are different.

In other words, the reversing unit 80 of this double-sided device has two stages (three or more stages) of the drawer amount of the drawer tray part 17 'to the front of the apparatus body (rightward in FIG. 8) with respect to the casing part 16'. A pair of guide plates 83A, 84A having the same number as the number of stages 2 that allows the drawer portion drawer amount regulating means to draw out the drawer tray portion 17 '. 83B and 84B are provided separately in the paper transport direction.
Note that the guide plates 83A, 84A and 83B, 84B opposed to each other in the vertical direction constitute a paper conveyance system together with paper conveyance rollers 85, 86 described later.

  Then, the guide plates 83A and 83B located on the upper side of the paired guide plates 83A and 84A and 83B and 84B are pulled out with respect to the guide plates 84A and 84B located on the lower side. In FIG. 8, which is the rear end side in the pulling-out direction, the left end is supported by fulcrum shafts 81 and 82 so as to be rotatable.

The guide plates 83A and 83B and 84A and 84B are the same parts, and the same sheet conveying rollers 85 and 86 are attached to the guide plates 83A and 83B and 84A and 84B, respectively.
Therefore, it is possible to reduce the cost of parts by manufacturing a large number of the same parts, and to reduce the cost of the mold at the part manufacturing stage, thereby reducing the cost.
The pair of guide plates 83A, 84A and 83B, 84B may be configured such that the guide plates 84A, 84B located on the lower side can also rotate.

Further, in this double-sided device, each pair of guide plates 83A, 84A and 83B, 84B divided into two in the paper transport direction is arranged with a gap in the pull-out direction of the pull-out tray portion 17 ', and the gap is set. A pair of fixed guide plates 89a and 89b is provided at the opened portion, and the presence or absence of paper in the conveyance path formed by the guide plates 89a and 89b is detected at the fixed guide plates 89a and 89b. A sensor with filler 91 as a detecting means is provided.
Note that guide rail portions 73 'and 74' are provided at portions corresponding to the lower surfaces of both side portions (front side and back side in FIG. 8) with respect to the pulling direction of the drawer tray portion 17 'of the housing portion 16'. Provided.

Next, the tray part pull-out amount restricting means described above will be described with reference to FIGS.
As shown in FIG. 9, the both ends of the lower surface of the drawer tray portion 17 'are positioned in positions corresponding to the guide rail portions 73' and 74 'of the housing portion 16', respectively, in the drawer direction of the drawer tray portion 17 '. A first convex rib 93 is formed in the vicinity of the tip, a second convex rib 94 is formed at a position slightly rearward from the approximate center, and a third convex rib 95 is formed at the rear end.
The second projecting rib 94 and the third projecting rib 95 have the same projecting height from the lower surface of the drawer tray portion 17 ', but the first projecting rib 93 has a projecting height slightly larger than those ribs. It is formed.

On the other hand, the guide rail portion 73 ′ on the side of the housing portion 16 ′ is formed with a concave portion 96 that allows the first convex rib 93 to be fitted therein, and a convex rib 97 adjacent to the concave portion 96. The concave portions 96 and the convex ribs 97 are similarly formed on the guide rail portion 74 ′ (located on the back side of 73 ′) located on the back side in FIG. 9 of the housing portion 16 ′.
Further, these convex ribs 93, 94, 95 and the concave portion 96 and the convex rib 97 are exaggerated in FIGS. 9 to 11 for convenience of illustration.

  The reversing unit 80 of this double-sided device is in the position shown in FIG. 9 when the drawer tray 17 'is inserted into a predetermined insertion position (position where a double-sided image can be formed) of the housing 16'. The first convex rib 93 of the drawer tray portion 17 ′ is fitted into the concave portion 96 on the housing portion 16 ′ side, and the left end surface of the first convex rib 93 in FIG. 9 is the right end surface of the convex rib 97. Abut.

In this state, when pulling out the drawer tray portion 17 ′ to the right in FIG. 9, the drawer tray portion 17 ′ is slightly lifted and pulled out so as to remove the first convex rib 93 from the concave portion 96.
Then, since the second convex rib 94 is formed on the bottom surface of the drawer tray portion 17 ′ slightly behind the center, when the drawer tray portion 17 ′ is pulled out to the position shown in FIG. The right end surface of the second convex rib 94 comes into contact with the left end surface of the convex rib 97 and becomes an intermediate pulling position (first pulling position).

In this state, only the guide plate 83B located on the front side of the apparatus can be opened in the arrow G direction. Therefore, if there is a jammed sheet, the sheet can be taken out in that state.
In addition, a jam is likely to occur on the leading end side in the pull-out direction of the pull-out tray portion 17 ′ on which the reverse roller 31 and the reverse guide plate 36 constituting the reverse mechanism are provided. Thus, jam processing can be performed in a state where the drawer tray portion 17 'is pulled out to an intermediate drawer position.

Next, when the drawer tray portion 17 ′ is further pulled out from the intermediate drawer position shown in FIG. 10, the drawer tray portion 17 ′ is slightly lifted again so that the second convex rib 94 gets over the convex rib 97. And pull it out.
Then, when the drawer tray portion 17 ′ is pulled out to the position shown in FIG. 11, the right end surface of the third convex rib 95 comes into contact with the left end surface of the convex rib 97, and becomes the second stage extraction position.

  In this state, as shown in the drawing, the guide plate 83A located on the rear end side in the pulling direction of the pulling tray portion 17 'can also be opened in the arrow G direction. Therefore, the paper jammed between the guide plates 83A and 84A can be easily taken out.

  As described above, the reversing unit 80 of the double-sided apparatus according to this embodiment can pull the apparatus main body forward with respect to the housing part 16 'of the drawer tray part 17' in two stages, and for each of the drawer stages. Since the guide plates 83B and 83A arranged in a divided state can be opened step by step, jam processing can be performed while adjusting the pull-out amount of the pull-out tray portion 17 ′ depending on the location where the jam occurs. The jam handling property can be improved.

  Further, as shown in FIG. 8, the reversing unit 80 of the double-sided apparatus arranges the pair of guide plates 83A, 84A and 83B, 84B at intervals in the pulling-out direction of the pull-out tray unit 17 '. Since the fixed guide plates 89a and 98b are provided in the opened portions and the sensor 91 with filler is provided in the fixed guide plates 89a and 89b, the user opens the guide plates 83A and 83B when a jam occurs. Even then, the user's hand or the like can be prevented from touching the sensor 91 with the filler.

As described above, the double-sided device and an image forming apparatus according to this invention can be utilized in an image forming apparatus such as a color image forming apparatus an image can be formed on both sides of the paper (duplex printing apparatus).

It is a whole block diagram which shows an example of the color image forming apparatus provided with another double-sided apparatus corresponding to the double- sided apparatus by this invention. It is a perspective view which similarly shows the entrance part of the housing | casing part which comprises the inversion part of the double-sided apparatus. It is a perspective view which similarly shows the removal prevention stopper provided in the inlet_port | entrance part of the housing | casing part with a housing | casing part. It is a front view which shows the state which similarly moved the prevention stopper from the 1st position to the 2nd position. Similarly, a schematic cross-sectional view showing a state in which the protrusion of the drawer tray portion pulled out comes into contact with the stopper for preventing the withdrawal tray from being pulled out of the housing portion when the stopper for preventing the withdrawal is in the first position. It is. Similarly, it is a schematic diagram showing a partial cross-section of a state in which the stopper cannot be inserted up to a predetermined insertion position even when the drawer tray portion is inserted into the housing portion when the stopper for preventing removal is in the second position. It is the schematic which expands and shows the state in which the drawer | drawer tray part was similarly inserted to the predetermined insertion position of the housing | casing part. It is the schematic which shows only the inversion part of one Embodiment of the double-sided apparatus by this invention. Similarly, in order to explain the tray part pull-out amount regulating means, it is an explanatory view showing a reversing part in a simplified manner. It is the schematic which shows the state which pulled out the drawer tray part of the inversion part of FIG. 8 to the middle drawer position. FIG. 6 is a schematic view showing a state where the drawer tray portion is similarly pulled out to a second-stage drawer position. It is a schematic block diagram showing an example of an image forming apparatus having a double-sided device capable of forming images on both sides of a conventional paper.

Explanation of symbols

1: Device main body 5: Double-sided device 16, 16 ': Case 17, 17': Drawer tray 23: Switching claw (conveying path switching means)
30: Paper discharge double-sided conveyance unit 31: Reverse roller 32: Vertical conveyance unit 33: Reversal unit 35: Paper conveyance roller 36: Reversal guide plates 46, 47, 83A, 83B, 84A, 84B, 89a, 89b: Guide plate 73 , 73 ', 74, 74': guide rail part 75: drop prevention stopper 80: reversing part 91: sensor with filler (detection means)
93: first convex rib 94: second convex rib 95: third convex rib 96: concave portion 97: convex rib

Claims (5)

In a double-sided apparatus including a casing unit fixed to the apparatus main body, and a drawer tray unit having a reversing mechanism that can be pulled out forward of the apparatus main body with respect to the casing unit and reverses the paper,
A tray part pull-out amount restricting means for restricting a pull-out amount of the pull-out tray part to the front of the apparatus main body with respect to the housing part in a plurality of stages;
The paper transport system of the drawer tray unit includes a pair of guide plates that are vertically opposed to each other, and the pair of guide plates has the same number of sheets as the number of drawer stages of the drawer tray unit regulated by the tray unit drawer amount regulating unit. It is provided divided in the conveying direction, and supports each guide plate located at least on the upper side of each of the divided pair of guide plates so as to be openable with respect to the guide plate located on the lower side ,
Each of the pair of guide plates divided into a plurality is arranged with a gap in the pull-out direction of the drawer tray portion, a fixed guide plate is provided in the gap, and a sheet is provided in the fixed guide plate portion. A double-sided device provided with a detecting means for detecting the presence or absence of the ink . When the image is formed on both the first side and the second side of the sheet, the sheet on which the image is formed on the first side is reversed so that the image is reversed on the second side. In a double-sided device that refeeds to form,
A paper discharge double-sided conveyance unit provided with a conveyance path switching unit that switches a conveyance direction between a direction in which the sheet on which the image is formed on the first surface is discharged out of the apparatus and a direction in which the paper is re-feeded; A vertical conveyance unit that conveys the paper guided in the direction of refeeding by the switching unit toward the lower side of the apparatus, and the paper conveyed through the vertical conveyance unit is received, and the reversing mechanism is used to invert the front and back surfaces. A reversing unit for refeeding to form an image on the second side,
The reversing portion is provided with a housing portion and a drawer tray portion that can be pulled out forward of the apparatus main body with respect to the housing portion.
To the drawer tray section, the reversing mechanism, a paper transport system that transports the paper toward the reversing mechanism, and a refeed that feeds the paper whose front and back are reversed by the reversing mechanism to form an image on the second surface. And a paper mechanism
A tray part pull-out amount restricting means for restricting a pull-out amount of the pull-out tray part to the front of the apparatus main body with respect to the housing part in a plurality of stages;
The sheet conveying system of the drawer tray unit includes a pair of guide plates that are vertically opposed to each other, and the number of the pair of guide plates is the same as the number of steps of the drawer tray unit that the tray unit drawer amount regulating unit regulates. It is provided divided in the paper transport direction, and supports each guide plate located at least on the upper side of each of the divided pair of guide plates so as to be openable with respect to the guide plate located on the lower side ,
Each of the pair of guide plates divided into a plurality is arranged with a gap in the pull-out direction of the drawer tray portion, a fixed guide plate is provided in the gap, and a sheet is provided in the fixed guide plate portion. A double-sided device provided with a detecting means for detecting the presence or absence of the ink .   3. The double-sided device according to claim 1, wherein each of the openable guide plates is rotatably supported at a rear end side in the pull-out direction of the pull-out tray portion.   The number of divisions of the pair of guide plates is two for the upper and lower guide plates, and the divided upper and lower guide plates are formed of the same parts, and the divided pair of guide plates. 4. The double-sided device according to claim 1, wherein the same sheet conveying roller is attached to each of the two. An image forming apparatus having a double-sided device according to any one of claims 1 to 4.

Images