JPH08143185A - Image forming device - Google Patents

Abstract

PURPOSE: To match the directions of images on the obverse and the reverse of a paper sheet with each other though the constitution is comparatively simple. CONSTITUTION: In a vertical conveyance passage 15 in the middle of conveyance of the paper sheet P, on one surface of which an image is formed by an image forming part 3, by a double surface device 2, a guide shoe 31 is brought into contact with a position eccentric from the center in the direction of width of a paper sheet crossing the paper conveyance direction of the tip of a paper sheet P at right angles, and the direction thereof is rotated in the same plane in a 180 deg. arc. Thus, when the paper sheet P is refed and an image is formed on the side where no image is formed, even when images on the obverse and the reverse of the paper sheet are usually upside down, the images are caused to coincide with each other even by an analogue type image forming device. Further, instead of the guide shoe 31, the eccentric position of the paper sheet is nipped between a rotary pad and an auxiliary rotary pad and may be rotated in the same plane in a 180 deg. arc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a sheet re-feeding unit for re-forming an image on a side of a sheet having an image formed on one side on which an image is not formed, The present invention relates to an image forming apparatus capable of aligning images formed on the front and back sides of a sheet when two-sided image formation is performed so that the top and bottom (upper and lower sides) of the sheets are not reversed.

[0002]

2. Description of the Related Art Some electrophotographic image forming apparatuses, such as copying machines and printers, are capable of forming images on both sides of a sheet or forming multiple images on one side of a sheet. In such an image forming apparatus, in the normal case, the sheets on each side of which an image has been formed are temporarily stacked on the intermediate tray of the re-feeding unit, re-fed, and the second image is transferred thereto. .

In this case, for example, when images are formed on both sides of the paper, it becomes difficult to see if the images formed on the front and back sides are upside down (upside down) as shown in FIG. Need to be aligned. However, in order to arrange the front and back images in the same direction, it is necessary for an analog type copying machine to make a copy in consideration of the direction of the image on the original and the direction in which the original is set on the contact glass.

That is, the originals D1 and D2 whose images are drawn on the surface of the paper in the direction shown in FIG. 14 are placed sideways with respect to the conveyance direction of the paper P indicated by the letter G as shown in the figure. 15 is set on the contact glass 81, and an image corresponding to the first original document D1 is formed on one surface of the paper P fed from the paper feeding unit 82 of the copying machine as shown in FIG. The sheet P is stacked on the intermediate tray 86 of the sheet re-feeding unit 85 through the double-sided conveyance path 84, and then the sheet is re-fed to form two sheets on the side on which the image is not formed. When an image corresponding to the eye original D2 is formed, the paper P discharged onto the paper discharge tray 87 has the front and back images oriented in the same direction, as shown in FIG.

However, as shown in FIG. 16, when it is necessary to feed the originals D1 'and D2' of large size in the vertical direction, the characters on the originals are oriented vertically with respect to the conveying direction as shown in the drawing. In such a case, on the paper P discharged onto the paper discharge tray 87 after double-sided copying, the characters are upside down (upper and lower) on the front and back sides (the broken line characters on the paper P indicate the characters transferred to the back side). ), Which causes inconvenience.

Therefore, in order to prevent such inconvenience, the image information read from the original is temporarily stored in the storage means, and the writing means using a laser beam or the like is used in accordance with the image information read from the storage means. In a digital copying machine that writes an image on a sheet, the direction of the image to be written is rotated by 180 ° so that the orientation of the image is aligned on the front and back sides of the sheet (for example, Japanese Laid-Open Patent Publication No. HEI 5).
232760).

However, since the analog double-sided copying machine as described above has no means for storing the image information read from such an original, for example, when the prism is rotated by 90 ° around the optical axis, the projected image is obtained. Is 180 °
By utilizing the change in direction, the direction of the image formed by rotating the prism is changed by 180 ° (see, for example, Japanese Patent Laid-Open No. 62-150361).

Further, an image is copied on one side of a sheet fed from the sheet feeding section by the image forming section, the sheet is once sent to the sheet discharging section, and then the sheet is reversed (the trailing edge is the leading edge). Re-feed the paper and feed it to the turntable, where
Rotate it by 0 °, convey it again to the image forming unit, copy the image on the back side this time, and discharge it to the paper output unit so that the images copied on the front and back of the paper do not turn upside down. There is also such a method (see Japanese Patent Application Laid-Open No. 1-162639). Furthermore, by devising the transport path, the paper on which one side of the image is formed is reversed by the reversing mechanism using reversing rollers and stacked on the intermediate tray etc. There are also those that form the image.

[0009]

However, in the case of the analog type double-sided copying machine in which the prism as described above is rotated by 90 ° about the optical axis, the structure becomes complicated and the space becomes large. There was a problem that it would end up. Further, also in the case of a double-sided copying machine in which a sheet is fed to a rotary table device provided in the transport path and rotated by 180 ° in the same plane, there is a problem that the device is likely to be large in size.

Further, in the case of a double-sided copying machine in which a sheet having an image formed on one side is inverted by a reversing mechanism to be stacked on an intermediate tray or the like and is re-fed to the image forming section, double-sided copying takes time. There is a problem that it is not efficient because it ends up. Further, there is also a problem that the cost is increased due to the necessity of the reversing mechanism.

The present invention has been made in view of the above problems, and when the images are formed on the front and back sides of the paper, the images are vertically (upper and lower) when the images are formed on the front and back sides of the sheet while being relatively compact and compact. ) Is intended to be aligned so that they are not reversed.

[0012]

In order to achieve the above object, the present invention provides an image forming apparatus such as that described above, in which a conveying path is provided between the image forming section and the re-feeding section. Provided is a paper rotating means for rotating the direction of the paper by 180 ° in the same plane by bringing the paper contact member into contact with a position eccentric from the center of the front end of the paper to be conveyed in the paper width direction orthogonal to the paper conveyance direction. At the same time, contact member moving means for retracting the sheet contact member from the transport surface of the transport path is provided.

Further, a rotatable rotary pad and a sheet conveyed along the convey path between the rotatable pad and the sheet are provided in the same conveyance path between the image forming section and the refeed section as described above. And an auxiliary rotary pad for rotatably holding the paper in the same plane in a state of being eccentric from the center of the paper width direction orthogonal to the paper conveyance direction, and at least one of the rotary pad and the auxiliary rotary pad. The image forming apparatus may be configured to include a rotating pad contacting / separating unit that contacts or separates one of the two with respect to the partner's rotating pad.

Alternatively, a rotatable rotary pad is provided in the transport path between the image forming section and the re-feeding section, and a sheet transported through the transport path is sandwiched between the rotary pad and the rotatable pad. An auxiliary rotating pad that holds the sheet rotatably in the same plane is provided, and a rotating pad contacting / separating unit that contacts and separates at least one of the rotating pad and the auxiliary rotating pad with respect to the partner's rotating pad, The image forming apparatus may be configured to include a rotation drive unit that rotates at least one of the rotation pad and the auxiliary rotation pad by 180 °.

Further, in any one of the above-mentioned image forming apparatuses, a manual feed feeder capable of feeding a document to the transport path is provided in the transport path between the image forming section and the position where the paper is rotated, and the paper is fed. A document take-out port for taking out the document fed from the manual feeder to the outside of the machine may be provided in the conveyance path between the position where the paper is rotated and the re-feed unit. In addition, in the same transport path between the image forming unit and the re-feeding unit,
It is also possible to provide a twist transport unit that twists the sheet transported through the transport path 180 ° and reverses the front and back.

[0016]

According to the image forming apparatus having the above-described structure, when an image is formed on both sides of a sheet, the sheet on which the image is formed on one side by the image forming section is conveyed to the re-feed section. In the path, the paper contact member of the paper rotating means is brought into contact with a position eccentric from the center of the paper width direction orthogonal to the paper conveyance direction at the leading end of the paper in the conveyance process, and its orientation is within the same plane.
Since it can be rotated by 80 °, its orientation is 180
° If you re-feed the rotated paper by the paper re-feed unit and form an image on the side where the image is not formed, even if the front and back images of the paper are upside down Even if the image forming apparatus is an analog type, it can be arranged.

In addition, a rotation for holding the sheet in the above-mentioned conveying process in a conveying path between the image forming section and the re-feeding section by sandwiching it at a position eccentric from the center of the sheet width direction orthogonal to the sheet conveying direction. By providing a pad, an auxiliary rotary pad, and a contacting / separating means for contacting / separating at least one of the pad and the auxiliary rotary pad with each other, a sheet having an image formed on one side as described above serves as an image forming unit. When the paper is being conveyed to the conveying path between the sheet refeeding section and the sheet being conveyed, the rotating pad and the auxiliary rotating pad sandwich the position eccentric from the center of the sheet width direction orthogonal to the sheet conveying direction. Since the sheet can be held and rotated by 180 ° in the same plane, the top and bottom of images on the front and back sides of the sheet can be similarly aligned.

Further, the above-mentioned rotary pad, the auxiliary rotary pad, and at least one of them are brought into contact with and separated from the other rotary pad in the conveyance path between the image forming section and the re-feeding section. By providing the means and the rotation driving means for rotating and driving at least one of the rotating pads, the sheet on which the image is formed on one side as described above is sandwiched and held by the rotating pad and the auxiliary rotating pad. In this state, the paper can be rotated by 180 ° in the same plane by the rotation driving means, so that the top and bottom of the images on the front and back of the paper can be aligned in the same manner.

Further, a manual feeding feeder which also serves as feeding of the original document is provided in the conveyance path between the image forming section and the position where the paper is rotated in the same plane, and the paper is rotated in the same plane. If a document exit for taking out the documents fed from the manual feeder is taken out of the machine in the transport path between the feeding position and the re-feed unit, the paper surface will be displayed when images are formed under normal conditions. If the image orientation is reversed on the reverse side, the originals are fed from the manual feeder, rotated by 180 ° for every other sheet at the position where they are rotated in the same plane, and then taken out from the original outlet. Then, if the originals are set one by one in the state of being taken out and double-sided image formation is performed, even in an analog image forming apparatus, it is possible to align the top and bottom of images on both sides of a sheet.

Further, if a twist conveying section for reversing the front and back by twisting the sheet conveyed through the conveying path by 180 ° is provided in the conveying path between the image forming section and the re-feeding section, as described above. Even in the case of a transport path in which the front and back images are turned upside down unless the paper with the image formed on one side is rotated 180 ° or the original is rotated 180 ° every other sheet, The paper on which an image is formed on one side can be conveyed again to the image forming section with the front and back reversed by twisting the paper by 180 ° in the twist conveying section, so that the front and back images of the paper can be aligned in the same direction. it can.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a perspective view showing a sheet rotating means of an image forming apparatus which is an embodiment of the present invention, FIG. 2 is a schematic view showing how the sheet rotating means rotates the sheet 180 ° in the same plane, and FIG. FIG. 3 is an overall configuration diagram showing a simplified image forming apparatus including the sheet rotating means.

The copying machine which is the image forming apparatus shown in FIG.
An automatic document feeder 20 is mounted on the upper portion of the apparatus main body 1, an image forming unit 3 is provided on the upper portion of the apparatus main body 1, and an image of a sheet P having an image formed on one side by the image forming unit 3 is provided on the lower portion. A double-sided device 2 which is a sheet re-feeding unit for performing image formation again is mounted on the surface on which the sheet is not formed. The image forming unit 3
In the figure, a drum-shaped photoconductor 5 rotating clockwise, a charging unit 6 provided around the photoconductor 5, and a developing unit 7
And a transfer unit 8 that doubles as a belt type transport device
And a cleaning unit 9.

The optical unit 1 is provided in the upper part of the apparatus main body 1.
1 is provided, the reflected light of the light emitted from the lamp 12 with respect to the document set on the contact glass 10 is incident on the surface of the photoconductor 5, and the charging unit 6 uniformly charges the surface of the photoconductor 5. The surface is exposed to form an electrostatic latent image on it.

The electrostatic latent image is developed with the toner supplied by the developing sleeve of the developing unit 7 to form a toner image (visible image). In a space between the image forming unit 3 and the double-sided device 2, paper feeding units 13 are detachably attached to the apparatus main body 1 in three stages (which can be increased / decreased as necessary) and are selected. The paper P is sent out one by one from the paper feeding stage by the paper feeding roller 16 that rotates at a predetermined timing, and the transfer unit 8 is provided at an accurate timing when the paper P coincides with the toner image on the photoconductor 5. It is conveyed toward the transfer unit.

A toner image is transferred to the upper surface side of the paper P in FIG. 1, the toner image is separated from the photoconductor 5 and conveyed to a fixing unit 17, where the toner is heated and fixed, and then a normal one-sided copy is performed. In this case, the sheet is discharged by the sheet discharge roller pair 14 onto the sheet discharge tray 4 outside the apparatus through the sheet discharge passage 18.

After the transfer is completed, the residual toner, paper dust, and other deposits remaining on the photoconductor 5 are removed by the cleaning blade provided in the cleaning unit 9, and the residual potential remaining on the photoconductor 5 is removed. Is removed by a charge eliminating lamp (not shown) to prepare for the next charging by the charging unit 6.

The double-sided device 2 temporarily stores a paper P having an image formed on one side thereof, and a predetermined paper sheet P discharged from the double-sided transport path 22 on the double-sided tray 21 so that the paper P can be re-fed. 3 and a sheet P on the double-sided tray 21 that is rotatable to a position indicated by a virtual line in FIG.
Re-feeding roller 24 for re-feeding paper, a re-feeding separation unit 25 for separating the re-fed paper P into one sheet, and a jogger (not shown) for aligning the positions of the papers stacked on the double-sided tray 21. Etc. Although not shown in the drawings, switching claws for feeding the paper to the intended conveyance paths are respectively provided at the branching portions of the conveyance paths for conveying the paper inside the apparatus main body 1. There is.

By the way, in this copying machine, a paper rotating device 30 as a paper rotating means is provided in the vertical conveying path 15 between the image forming section 3 and the double-sided device 2. The paper rotating device 30
Is a position eccentric to the right in the figure from the center CL of the front end Pa of the paper P conveyed in the direction A as shown in FIG. 1 in the paper width direction orthogonal to the paper conveyance direction, as shown in FIG. The guide shoe 31 as a paper contact member is brought into contact with the guide plate 32 to rotate the paper P in the same plane by 180 ° (P to P ') as shown in FIG. .

The paper rotating device 30 is shown in FIG.
A solenoid 33 for retracting the guide shoe 31 to a position indicated by an imaginary line in which the leading end surface 31a does not project from the transport surface 32a of the guide plate 32 so as not to contact the sheet P transported in the vertical transport path 15 as shown in FIG. It is provided. In this embodiment, the solenoid 33 corresponds to a contact member moving unit that retracts the guide shoe 31 that is a paper contact member from the transport surface of the vertical transport path 15.

On the guide plate 32, there is formed a circular guide portion 32b which widens the conveying path in an arc shape. Further, on the upper side and the lower side of the circular guide portion 32b of the guide plate 32, the roller openings 32c, 3 are formed substantially at the center in the width direction of the conveyance path.
2d are formed respectively, and the intermediate rollers 34 are rotatably provided in the respective openings. A part of each of the intermediate rollers 34 is slightly projected from the transport surface 32a of the guide plate 32, so that the transportability of the sheet P transported on the guide plate 32 is improved.

The guide shoe 31 is formed by attaching an elastic body such as rubber to the tip of a rod-shaped member such as iron, and rounding the portion where the sheet abuts. Thus, even if the guide shoe 31 comes into contact with a sheet that moves downward in the vertical transport path 15 due to gravity, the leading end of the sheet does not fold.

As described above, the guide shoe 31 can be retracted by the solenoid 33 to a position where the front end surface 31a thereof does not project from the conveying surface 32a of the guide plate 32. 1 along the guide hole 32e formed along the vertical direction).
It can also be moved in any direction.

The movement of the guide shoe 31 along the guide hole 32e is performed by the mechanism shown in FIG. This mechanism includes a solenoid 33 that holds the guide shoe 31 on the movable shaft 33a so that the guide shoe 31 can move in the arrow C direction, and a holding member 35.
The rack 36 is fixed to the holding member 35 as the moving side in the arrow E direction orthogonal to the arrow C direction which is the moving direction of the guide shoe 31.

A motor 37 for raising and lowering is mounted on the rack 36.
When the pinion 38 fixed to the rotating shaft of the rack is engaged and the motor 37 is rotated in both forward and reverse directions, the rack 36
Moves up and down in the figure, and the guide shoe 3
1 is moved up and down via the holding member 35 and the solenoid 33. The motor 37 and the solenoid 33 are drive-controlled by a drive circuit 45 that drives them.

The drive circuit 45 is controlled by the control device 40 shown in FIG. The control device 40 includes a central processing unit (CPU) having various judgment and processing functions, a ROM storing each processing program including programs necessary for controlling the entire copying machine and fixed data, and processing data. It is a microcomputer including a RAM that is a data memory for storing data and an input / output circuit (I / O).

When the double-sided selection key 41 is pressed during double-sided copying, the control device 40 sends a double-sided copy signal from the double-sided selection key 41, and an image of the front and back sides of the sheet during double-sided copying. 1 sheet of paper to align upside down
A paper rotation signal is input from the paper rotation key 42 which is pressed to rotate in the same plane by 80 °.

When the copy start key 43 is pressed at the start of copying, the copy start key 4 is pressed.
Input the copy start signal from 3. Further, various sensor signals and the like are respectively input from various sensors provided in each part of this copying machine. Then, the control device 40 sends signals for driving the solenoid 33 and the motor 37 to the drive circuit 45, and various signals for driving various drive systems and loads in the copying machine. Signal is output at a predetermined timing.

When performing double-sided copying, this copying machine selects double-sided copying with the double-sided selection key 41 shown in FIG.
When the orientation of the document set is such that the characters are in the horizontal orientation as shown in FIG. 16, a paper rotation key 42 for rotating the paper having an image formed on one side by 180 ° in the same plane is further added. Push.

Then, the automatic document feeder 2 shown in FIG.
The original is set to 0 and the copy start key 43 is pressed.
By doing so, double-sided copying is started by rotating the paper on which an image is formed on one side by 180 °. That is, an image is formed on one side of the sheet P fed from the sheet feeding unit 13 of one of the sheet feeding stages through the image forming process similar to the case of the one-sided copying described in FIG.
Is formed by.

The paper P is sent to the vertical transport path 15, and by pressing the paper rotation key 42, the guide shoe 31 is driven to a position protruding from the transport surface 32a of the guide plate 32 as shown in FIG. It is conveyed to the rotating sheet rotating device 30. Then, at the timing when the leading edge Pa of the sheet P contacts the guide shoe 31, the motor 3 shown in FIG.
7 is driven by the drive circuit 45 (FIG. 5) to rotate, so that the rack 36 is moved upward by the pinion 38, whereby the guide shoe 31 is lifted as indicated by an arrow in FIG.

At that time, as described above, the guide shoe 31 contacts the tip end Pa of the paper P at a position eccentric to the right in FIG. 2 from the center CL (FIG. 1) in the paper width direction orthogonal to the paper transport direction. Since the paper P is in the vertical conveyance path 15
In the same plane by using the circular guide portion 32b as shown by the phantom line in the figure, due to the inertial force when moving downwards due to gravity and the rotational force generated by the rising of the guide shoe 31. And rotate 180 °.

The timing at which the guide shoe 31 rises is a sensor (not shown) provided upstream of the paper rotating device 30 in the vertical transport path 15 in the paper transport direction.
The controller 40 shown in FIG. 5 inputs a signal that the passage of the sheet P has been detected, and is controlled by the drive circuit 45 based on the input timing of the signal.

In this way, the paper P is fed to the paper rotating device 3
In a state where the sheet is conveyed to the double-sided conveying path 22 shown in FIG. 3 and discharged onto the double-sided tray 21 in a state in which the sheet is changed to a direction different by 180 ° before and after being sent to 0, and it is re-fed at a predetermined position It is aligned by the roller 23. And 2
When the first document is conveyed onto the contact glass 10 by the automatic document feeder 20, the sheet P on the double-sided tray 21 is re-fed by the re-feeding roller 24, and the sheet P passes through the double-sided conveyance path 26. The image is conveyed to the image forming unit 3, and an image corresponding to the second original is formed on the surface on which the image is not formed.

At this time, since the direction of the sheet P is rotated by 180 ° as shown in FIG. 6, the second original D2
The image (indicated by B) corresponding to is aligned with the top and bottom of the first image (indicated by A) already formed on the back surface. Then, the paper P on which images are formed on both the front and back sides is discharged by the paper discharge roller pair 14 onto the paper discharge tray 4 outside the machine through the discharge conveyance path 18 in FIG. Similarly, the same image forming operation is repeatedly performed on the second and subsequent sheets, and the orientations of the front and back images are aligned.

Further, as in the orientation of the original shown in FIG. 14, when the two-sided copying is performed in the setting posture in which the orientation of the characters of the original D set on the contact glass 10 is the normal position and the orientation is not horizontal, Since it is not necessary to rotate the paper with the image formed on one side in the same plane by 180 °,
In this case, the copy start key 43 is pressed without pressing the paper rotation key 42 after pressing the double-sided selection key 41 shown in FIG.
Press.

In this case, the leading end surface 31a of the guide shoe 31 of the sheet rotating device 30 shown in FIG.
The image process of double-sided copying described above is performed in the state of being retracted to the position indicated by the virtual line that does not project from the second transport surface 32a. Therefore, the paper P fed into the vertical conveyance path 15 is guided to the double-sided conveyance path 22 shown in FIG. 3 and stacked on the double-sided tray 21 without being rotated by 180 °, The sheet is re-fed and an image is formed on the surface on the side where the image is not formed, and the image is discharged onto the discharge tray 4.

FIG. 7 is a perspective view showing a means for rotating a sheet of an image forming apparatus showing another embodiment of the present invention, and FIG. 8 shows a state in which the sheet is rotated 180 ° in the same plane by the sheet rotating means. It is a schematic diagram showing. The image forming apparatus according to this embodiment is different from the image forming unit 3 for the copying machine described in FIG.
The sheet rotating means 30 provided in the vertical conveyance path 15 between the sheet re-feeding section 2 and the sheet re-feeding section 2 is replaced with a sheet rotating means as shown in FIG.

That is, the vertical conveying path 15 is provided with guide plates 52 having circular guide portions 52a and 52b on both sides thereof, and the vertical conveying path 15 is located substantially in the middle of the left and right circular guide portions 52a and 52b of the guide plate 52. Center line CL in the width direction
7, a circular pad opening 52c is formed at a position slightly eccentric to the right in FIG. 7, and the auxiliary rotary pad 53 is substantially the same as the conveyance surface 52d or the vertical conveyance path 15 in the pad opening 52c. It is arranged so as to slightly project so as not to affect the conveyance of the conveyed paper P, and it is rotatably held by a support member (not shown).

Further, the rotary pad 51 is rotatably arranged corresponding to the auxiliary rotary pad 53, and the rotary pad 5
1 is fixed to the movable shaft 54a of the solenoid 54 which is the rotating pad contacting / separating means, and the rotating pad 51 can be moved toward and away from the auxiliary rotating pad 53 (direction of arrow F).

Since the auxiliary rotary pad 53 is arranged at a position slightly eccentric to the right in FIG. 7 with respect to the center line CL of the guide plate 52 as described above, the auxiliary rotary pad 53 is provided.
And the rotary pad 51, the paper P conveyed along the vertical conveyance path 15 is sandwiched at a position eccentric from the center (coincident with CL in FIG. 7) in the paper width direction orthogonal to the paper conveyance direction. In this state, it can be rotated in the same plane along the transport surface 52d.

The position of the rotary pad 51 and the auxiliary rotary pad 53 on the paper surface that sandwiches the paper P is slightly lower in FIG. 7 than the center in the paper transport direction. Further, both the rotary pad 51 and the auxiliary rotary pad 53 are made of, for example, a rubber material having a high frictional resistance at the portions that come into contact with the paper P, so that the paper holding force is increased. In order to allow both of these pads to easily rotate with a light actuation force, they are held by, for example, bearings having excellent rotatability. It should be noted that the side on which the pad is brought into contact with and separated from the mating pad is not limited to the rotary pad 51, but it may be the side of the auxiliary rotary pad 53, or both of them may be moved to be brought into contact with or separated from the pad. Good.

According to this embodiment, when it is necessary to rotate a sheet having an image formed on one side by 180 ° in the same plane in order to align the orientations of the images on the front and back sides during double-sided copying, FIG. When the paper P is conveyed onto the guide plate 52, the solenoid 54 is operated by the rotation pad 51 and the auxiliary rotation pad 53 at a timing below the center of the paper P in the paper conveyance direction. The paper P is sandwiched between the rotary pad 51 and the auxiliary rotary pad 53 and held by frictional force.

At this time, the position where the paper P is sandwiched is as shown in FIG. 7 from the center in the paper width direction orthogonal to the paper transport direction as described above.
At a position eccentric to the right side, and further below the center of the paper P, and the paper P is held while moving in the vertical transport path 15 so as to fall by gravity,
The inertial force rotates 180 ° as shown in FIG.
Therefore, also in this embodiment, the top and bottom directions of the images on the front and back sides of the paper can be aligned.

When the original is set in the direction in which it is not necessary to rotate the paper by 180 ° in the same plane (in the case of the original set in FIG. 14), the solenoid 54 is not operated and the rotary pad 51 is assisted. Rotating pad 5
Separated from 3. According to this embodiment, the paper is placed in the same plane without using a drive source such as a motor.
Since it can be rotated by 0 °, the device can be made smaller by that amount and the cost can be reduced.

FIG. 9 is a perspective view showing an embodiment in which a rotary drive means for driving the rotary pad is provided. In this embodiment, of the rotary pad 51 and the auxiliary rotary pad 53 described with reference to FIGS. 7 and 8, a stepping motor 57 that rotationally drives the rotary pad 51, and the rotation pad by controlling the rotation of the stepping motor 57. There is provided a control circuit 58 for controlling 51 to rotate by 180 °.

In this way, if the rotating pad 51 is rotated by the stepping motor 57, the rotating pad 5
1 and the auxiliary rotation pad 53 between the vertical conveyance path 15 (see FIG. 3)
Even if it is provided other than the above, since the paper can be surely rotated by 180 ° in the same plane, there is no restriction on the layout of the device for rotating the paper, which saves space in the image forming apparatus. It becomes effective.

FIG. 10 is a schematic view mainly showing a sheet conveying path of an embodiment of an image forming apparatus provided with a manual feeding feeder capable of feeding a document to the conveying path, and the portions corresponding to those in FIG. Is attached. A copying machine, which is an image forming apparatus according to this embodiment, feeds a document to a vertical conveyance path 15 between the image forming unit 3 and a sheet rotation device 30 at a position for rotating a sheet. A manual feed feeder 60 is provided, and a document fed from the manual feed feeder 60 is taken out to the outside of the apparatus by opening the door 66 in the conveyance path 61 between the sheet rotating device 30 and the refeed unit 68. An outlet 62 is provided.

The manual feeder 60 has a feed roller 63.
It is possible to continuously feed a large number of documents from there. When the manual feed feeder 60 is used as a manual feed feeder for feeding the paper P on which an image is transferred, the paper P is set on the manual feed tray 64 and directly fed to the double-sided transport path 26. .

Further, when it is desired to change the orientations of the originals so that the images formed on the front and back sides of the papers are aligned on the top and bottom when the two-sided copy is made on the papers, a plurality of originals are arranged in page order in the manual feed tray 64 Set them on the top and feed them one by one in the vertical transport path 1
5 is fed to the sheet rotating device 30 to rotate even-numbered pages (even number of fed sheets) of 2, 4, 6 ... 180 ° in the same plane by the sheet rotating device 30, and then the stack tray is used. Stack at 65.

After feeding all the originals, if the originals are taken out from the original take-out port 62, each even page of the originals is aligned in a direction rotated by 180 ° with respect to the odd pages. Therefore, the original document is directly transferred to the paper rotation device 30.
In another copying machine not having a sheet, the original setting posture shown in FIG. 16 (since FIG. 16 is also used for other explanations, the original D2 'on the second page is rotated by 180 ° with respect to the position shown. If two-sided copying is performed in the same direction, the images formed on the front and back of each sheet are aligned. The operator presses a selection key (not shown) to selectively use the manual feeding feeder 60 for manually feeding the sheets and for rotating the originals one by one to align them.

FIG. 11 is a schematic view mainly showing the paper transport path of the embodiment of the image forming apparatus in which the twist transport section is provided in the transport path between the image forming section and the re-feed section, and FIG. 12 is the twist transport. FIG. 4 is a perspective view showing a part, and parts corresponding to those in FIG. 3 are denoted by the same reference numerals. In the copying machine which is the image forming apparatus according to this embodiment, the vertical conveyance path 15 is conveyed to the vertical conveyance path 15 between the image forming section 3 and the first double-sided conveyance path 71 which serves as a re-feeding section. A twist conveyance unit 70 is provided which twists the paper 180 ° and reverses the front and back.

Further, from the vertical transport path 15 to the twist transport section 7
A second double-sided conveyance path 72 is provided in which the paper P is turned upside down and fed to the first double-sided conveyance path 71 without passing 0.
Transport rollers 75a, 75b, 75c, and 75d (the number of which can be increased or decreased as appropriate) are provided in the first and second double-sided transport paths 71 and 72, respectively.

As shown in FIG. 12, the twist conveying section 70 is arranged so that a guide plate 76 twisted by 180 ° twists the paper P conveyed therethrough by 180 ° without changing the paper passing direction so that the front and back sides are reversed. Although not shown in FIG. 12 because it is complicated, two guide plates 76 are provided in parallel, and the paper P is placed between the guide plates 76 and 76.
Is transported.

The guide plate 76 may be a plurality of rod-shaped guides, one of which extends in the carrying direction at a predetermined distance from the carrying surface of the guide plate 76. Roller openings 76a are formed in the center of the guide plate 76 in the widthwise direction at predetermined intervals in the paper transport direction, and the transport rollers 77 are formed in the respective roller openings 76a.
Each of them projects toward the transport surface by a predetermined amount suitable for transporting the sheet. The transport roller 77 may be a transport belt. The guide plate 76 is preferably formed of a material such as resin having a high paper-passing property at least on its transport surface.

Further, the twist carrying section 70, as in the embodiment shown in FIG.
It is effective in the layout of the copying machine if it is arranged at a portion where the paper advancing direction of the conveying path is changed by 90 ° so as to reach the double-sided conveying path 71. In this copying machine, when the orientations of the images formed on the front and back sides of the paper are aligned when double-sided copying is performed, when the original is set in the orientation shown in FIG. The sheet P having an image formed on one side in the image forming unit 3 is conveyed to the vertical conveyance path 15, and is twisted by 180 ° through the twist conveyance section 70 to be fed to the first double-sided conveyance path 71 in a state where the front and back are reversed. .

Then, the paper P is conveyed to the conveying rollers 75a,
The sheet is re-fed at 75b, and the image forming unit 3 forms the next image on the surface on the side where the image is not formed. Therefore, the top and bottom of the images on the front and back of the paper are aligned. When it is not necessary to turn over the paper (in the case of the document set in FIG. 14), the paper P having an image formed on one side is conveyed from the vertical conveyance path 15 to the second double-sided conveyance without passing through the twist conveyance section 70. The sheet is conveyed to the path 72, and is turned upside down by the conveying rollers 75c and 75d to be fed to the first double-sided conveying path 71. And
The sheet P is conveyed by the conveyance roller 75 in the first double-sided conveyance path 71.
The paper is re-fed rightward in FIG. 11 by a and 75b, and the image forming unit 3 forms the next image on the surface on the side where the image is not formed. Also in this case, the top and bottom of the images on the front and back of the paper are aligned.

The copying machine is also capable of performing multiple image formation (composite) in which an image is formed again on the surface of the paper on which the image is formed. In that case,
The sheet having the image formed on one side is directly conveyed from the vertical conveyance path 15 to the first double-sided conveyance path 71.

Although the respective embodiments have been described above, FIG.
In the embodiment, the re-feeding unit 2 is provided in the double-sided conveyance path 26, and the re-feeding direction of the paper in the re-feeding unit is set to the right side in FIG. The double-sided conveyance path 22 and the double-sided conveyance path 22 may be eliminated. Further, in FIG. 3, the re-feeding unit 2 and the double-sided conveying path 22 are eliminated, and the sheet passing through the sheet rotating device 30 is immediately reversely rotated by the conveying roller 39 to be conveyed to the double-sided conveying path 26, which is stacked. Alternatively, the sheet may be re-fed to the image forming unit 3 again sheet by sheet. In this case, the portion where the transport roller 39 is provided functions as a re-feeding unit.

[0069]

As described above, according to the present invention, even when images are formed on both sides of a sheet by an analog image forming apparatus, even if the front and back images are upside down, By rotating the paper on one side of which the image is formed by 180 ° in the same plane by the paper rotating means having a relatively simple structure, the directions of the images can be aligned. Therefore, double-sided image formation can be performed in a short time without using a dedicated sheet reversing device.

Further, a rotation for holding the paper in the above-mentioned carrying process in a carrying path between the image forming section and the re-feeding section while sandwiching it at a position eccentric from the center of the paper width direction orthogonal to the paper carrying direction. By providing a pad, an auxiliary rotary pad, and a contacting / separating means for contacting / separating at least one of the pad and the auxiliary rotary pad, a sheet having an image formed on one side and being in the process of conveyance is used as the rotary pad. Since it can be rotated 180 ° in the same plane by utilizing the inertial force of the paper simply by holding it by the auxiliary rotation pad, the device can be made smaller than when using a rotation means such as a motor. can do. In this case, if the paper is rotated in the vertical transport path, gravity can be used to rotate the paper, so that the paper can be rotated more efficiently.

Further, by providing a rotation driving means for rotating at least one of the above-mentioned rotary pad and auxiliary rotary pad, the rotation of the paper is forcibly performed even in a place other than the vertical conveyance path. As a result, there is no restriction on the transport path for rotating the paper, which increases the degree of freedom in design and saves space.

In addition, a manual feeding feeder which also serves as the feeding of the original document to the conveyance path is provided in the conveyance path between the image forming section and the position where the paper is rotated in the same plane, and the paper is kept in the same plane. If a document outlet for taking out the documents fed from the manual feeder is taken out of the machine in the conveyance path between the rotating position and the re-feed unit, every other document inserted from the manual feeder is the same. Since it is possible to rotate the paper 180 degrees in the plane and take it out, if the original is set in the taken out state, even if the image forming apparatus does not have a rotating device that rotates the paper 180 degrees, the double-sided image It is possible to align the top and bottom of images on the front and back sides of the sheet in forming.

Further, if a twist conveying section for reversing the front and back by twisting the sheet conveyed along the conveying path by 180 ° is provided in the conveying path between the image forming section and the re-feeding section, as described above. 180 ° in the same plane on paper with an image formed on one side
Align the front and back images of paper with each other even when the paper is in the form of a conveyance path where the front and back images are reversed unless they are rotated or rotated by 180 degrees for every other document. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sheet rotating unit of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing how the paper is rotated 180 ° in the same plane by the paper rotating means.

FIG. 3 is an overall configuration diagram showing a simplified image forming apparatus similarly including the sheet rotating means.

4 is a perspective view showing a mechanism for moving a guide shoe 31 of the sheet rotating means of FIG.

5 is a block diagram showing a control system of a copying machine which is the image forming apparatus of FIG.

FIG. 6 is a perspective view showing a state in which a sheet having an image formed on one side thereof is rotated by 180 ° in the same plane and conveyed to an image forming unit so that the front and back images are aligned in the same direction.

FIG. 7 is a perspective view showing a means for rotating a sheet of an image forming apparatus showing another embodiment of the present invention.

FIG. 8 is a schematic view showing how the paper is rotated 180 ° in the same plane by the paper rotating means.

FIG. 9 is a perspective view showing an embodiment provided with a rotation driving means for driving a rotation pad.

FIG. 10 is a schematic diagram mainly showing a sheet conveyance path according to an embodiment of the image forming apparatus provided with a manual feeder capable of feeding a document to the conveyance path.

FIG. 11 is a schematic diagram mainly showing a sheet transport path of an embodiment of the image forming apparatus in which a twist transport section is provided in the transport path between the image forming section and the re-feeding section.

FIG. 12 is a perspective view showing the twist carrying section of the same.

FIG. 13 is a schematic view showing a case where images formed on both sides of a sheet are turned upside down.

FIG. 14 is a plan view showing a method of setting a document in which the images formed on both sides of the paper have the same orientation in the vertical direction.

FIG. 15 is a schematic configuration diagram showing an example of a conventional copying machine capable of double-sided copying.

FIG. 16 is a plan view showing a method of setting a document in which the directions of images formed on both sides of the paper are opposite to each other in the vertical direction.

[Explanation of symbols]

 1: Device main body 2: Double-sided device (refeed unit) 3: Image forming unit 15: Vertical transport path 30: Paper rotating device (paper rotating unit) 31: Guide shoe (paper contact member) 32a: Transport surface 33: Solenoid 51: Rotating pad 53: Auxiliary rotating pad 54: Solenoid (rotating pad contacting / separating means) 57: Stepping motor (rotational driving means) 60: Manual feeder 62: Document outlet 70: Twist transport unit P: Paper

Claims (5)

[Claims] 1. An image forming unit in a main body of the apparatus, and a sheet re-feeding unit for forming an image again on a non-image side of a sheet having an image formed on one side by the image forming unit. In an image forming apparatus provided with the image forming apparatus, a position on a conveyance path between the image forming unit and the re-feeding unit, which is eccentric from a center in a paper width direction orthogonal to a paper conveyance direction of a front end of a paper conveyed on the conveyance path. A sheet rotating means for rotating the orientation of the sheet by 180 ° in the same plane by bringing the sheet contacting member into contact with the sheet contacting member, and moving the contacting member to retract the sheet contacting member from the transport surface of the transport path. An image forming apparatus comprising means. 2. An image forming unit in a main body of the apparatus, and a re-feeding unit for forming an image again on a non-image side of a sheet having an image formed on one side by the image forming unit. In an image forming apparatus provided with the sheet, a sheet of paper that is conveyed along the conveying path between the rotatable pad and the rotating pad is provided in the conveying path between the image forming section and the re-feeding section. And an auxiliary rotary pad for rotatably holding the paper in the same plane in a state of being eccentric from the center of the paper width direction orthogonal to the paper transport direction, and at least the rotary pad or the auxiliary rotary pad. An image forming apparatus, comprising: a rotating pad contacting / separating means for contacting / separating one of the rotating pads with the other rotating pad. 3. An image forming unit in the main body of the apparatus, and a sheet re-feeding unit for forming an image again on the side of the sheet on which an image is formed on one side of the image forming unit on the side where the image is not formed. In an image forming apparatus provided with the image forming apparatus, a rotatable rotation pad is provided in a conveyance path between the image forming unit and the re-feeding unit, and a sheet conveyed in the conveyance path is interposed between the rotation pad and the rotation pad. An auxiliary rotating pad for rotatably holding the sheet in the same plane in the same state, and at least one of the rotating pad and the auxiliary rotating pad is brought into contact with or separated from the partner's rotating pad. An image forming apparatus comprising: a separating unit and a rotation driving unit that rotationally drives at least one of the rotation pad and the auxiliary rotation pad by 180 °. 4. The image forming apparatus according to claim 1, wherein a document is fed to a conveyance path between the image forming unit and a position where the sheet is rotated. In addition to providing a manual feed feeder, a document take-out port for taking out a document fed from the manual feed feeder to the outside of the machine is provided in the conveyance path between the position for rotating the paper and the re-feeding unit. An image forming apparatus characterized by the above. 5. An image forming unit in the main body of the apparatus, and a re-feeding unit for forming an image again on the surface of the paper on which the image is formed on one side of the image forming unit on the side where the image is not formed. In the image forming apparatus provided with the above, a twist conveying unit that twists a sheet conveyed through the conveying path by 180 ° and reverses the front and back sides is provided in a conveying path between the image forming unit and the re-feeding unit. A characteristic image forming apparatus.