JP2015105155A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a printed medium from being entangled in a discharge roller pair which is rotating inversely.SOLUTION: An image formation device includes a housing part in which a printed medium is loaded and which makes a medium whose one side is printed temporarily escape at the time of both-side printing, transportation means which, at the time of both-side printing, stops transportation in a state in which a rear end part, in the direction transported to the housing part, of the medium whose one side has been printed is pinched, and makes the medium whose one side has been printed temporarily escape to the housing part, for inverse rotation thereafter and transportation, and a protrusion part which protrudes in between the medium loaded in the housing part and the medium whose one side is printed when the transportation means rotates inversely.

Description

  The present invention relates to an image forming apparatus that performs duplex printing.

  In a conventional image forming apparatus, when performing duplex printing, a medium on which one side is printed is temporarily retracted to a discharge tray with the discharge roller pair sandwiching a part of the medium, and then the discharge roller pair rotates reversely. In some cases, the other side of the medium is printed by a switchback operation that reverses the medium (see, for example, Patent Document 1).

JP 2009-3352 A

However, in the conventional image forming apparatus, a pair of discharge rollers in which the printed medium stacked on the discharge tray is adsorbed by static electricity or the like on the medium temporarily retracted on the discharge tray, and the printed medium is reversely rotated. There is a problem of being caught in.
An object of the present invention is to solve such a problem, and an object of the present invention is to prevent a printed medium stacked on a discharge tray from being caught by a pair of discharge rollers rotating in reverse.

  Therefore, the present invention provides a storage unit for stacking printed media and temporarily retracting a medium on which one side is printed during duplex printing, and the accommodation of the medium on which the one side is printed during duplex printing. The conveying means that stops conveyance while sandwiching the rear end in the direction of conveyance to the section, temporarily retracts the medium on which the one side has been printed, and then conveys the medium in the reverse direction, and the conveying means is reversed. And a protruding portion protruding between the medium stacked in the accommodating portion and the medium on which the one side is printed when rotating.

  According to the present invention thus configured, it is possible to obtain an effect that it is possible to suppress the printed medium from being caught by the pair of discharge rollers rotating in the reverse direction.

1 is a schematic side view illustrating a configuration of a composite apparatus including an image forming apparatus according to a first embodiment. Explanatory drawing near the stopper guide in the first embodiment The perspective view of the stopper guide in a 1st Example Sectional view near the stopper guide in the first embodiment Explanatory drawing which shows operation | movement of the separation mechanism in 1st Example. Explanatory drawing which shows operation | movement of the separation mechanism in 1st Example. Explanatory drawing which shows operation | movement of the separation mechanism in 1st Example. Explanatory drawing near the stopper guide in the second embodiment Explanatory drawing which shows operation | movement of the separation mechanism in 2nd Example. Sectional drawing which shows operation | movement of the stopper guide vicinity in 2nd Example. Sectional drawing which shows operation | movement of the stopper guide vicinity in 2nd Example. Explanatory drawing which shows operation | movement of the separation mechanism in 2nd Example. Sectional drawing which shows operation | movement of the stopper guide vicinity in 2nd Example. Sectional drawing which shows operation | movement of the stopper guide vicinity in 2nd Example. Explanatory drawing which shows operation | movement of the separation mechanism in 2nd Example. Sectional drawing which shows operation | movement of the stopper guide vicinity in 2nd Example. Sectional drawing which shows operation | movement of the stopper guide vicinity in 2nd Example.

  Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view illustrating a configuration of a composite apparatus including an image forming apparatus according to the first embodiment.
In FIG. 1, the composite apparatus 100 includes an image reading apparatus 102 that reads a document and generates print data, and a printer 101 that prints on a sheet 21 based on the print data generated by the image reading apparatus 102. Note that the printer 101 and the image reading apparatus 102 are connected to be communicable.
A printer 101 as an image forming apparatus receives print data from the image reading apparatus 102, forms an electrostatic latent image based on the received print data, develops the formed electrostatic latent image into a developer image, and develops the image. The agent image is transferred and printed on a paper 21 as a medium.

  The printer 101 includes a paper cassette 2 that stores paper 21, a paper feed roller 3 that takes out the paper 21 one by one from the paper cassette 2 and feeds it to the conveyance path 15, and a medium detection sensor that detects the presence or absence of the paper 21. 4, 7, 38, and 39, a pair of conveyance rollers 5 and 6 that are arranged along the conveyance path 15 and convey the paper 21, an image forming unit 8 that transfers the developer image to the conveyed paper 21, and a transfer A fixing unit 9 for fixing the developer image formed on the paper 21, a pair of discharge rollers 10 and 19 for discharging the paper 21 on which the developer image is fixed to the discharge tray 20, and a printer cover 14 that is a housing of the printer 101. And a discharge tray 20 formed on the upper surface of the printer cover 14.

In addition to the above-described configuration, the printer 101 has a reverse conveyance path 13 that is a path for conveying the paper 21 reversed by a switchback operation described later, and a paper 21 that is reversed from the conveyance path 15 to the reverse conveyance path 13. The guide separator 11 is arranged along the reverse conveyance path 13 and includes a conveyance roller pair 12 that conveys the reversed paper 21 and a stopper guide 36 described later.
The paper cassette 2 is disposed below the printer 101 and stores the paper 21 in a stacked manner.
The paper feed roller 3 takes out the paper 21 one by one from the paper cassette 2 and feeds it to the image forming unit 8 through the transport path 15. The paper feed roller 3 is rotated by a motor (not shown) and is not shown inside. Since the one-way clutch mechanism is built in, even when the rotation drive is stopped, the idle rotation is possible in the rotation direction indicated by the arrow B in the figure.

The conveyance path 15 is a path for conveying the sheet 21 from the sheet cassette 2 to the discharge tray 20 through the image forming unit 8 and the fixing unit 9.
The medium detection sensors 4 and 7 are arranged on the upstream side of the conveyance roller pairs 5 and 6 in the conveyance direction indicated by the arrow F in the drawing, and detect the presence or absence of the paper 21.
The conveyance roller pairs 5 and 6 are disposed along the conveyance path 15 and are driven to rotate by a motor (not shown), and convey the paper 21 based on a signal detected by the medium detection sensors 4 and 7. Further, the transport roller pairs 5 and 6 have a skew correction mechanism for correcting the inclination (skew) of the paper 21.

The image forming unit 8 is disposed at the center of the printer 101 and transfers the developer image formed based on the print data onto the paper 21.
The fixing unit 9 is disposed downstream of the image forming unit 8 in the conveyance direction indicated by an arrow F in the drawing, and sandwiches the sheet 21 with rollers, and conveys the developer while applying heat and pressure and transferred to the sheet 21. Fix the image.
The medium detection sensor 38 is arranged on the upstream side in the transport direction indicated by the arrow F in the drawing of the discharge roller pair 19 and detects the presence or absence of the paper 21.
The discharge roller pairs 10 and 19 as the conveying means are arranged on the downstream side of the medium detection sensor 38 in the conveyance direction indicated by the arrow F in the drawing, and convey the paper 21 to the discharge tray 20.
Further, the discharge roller pairs 10 and 19 perform a switchback operation during duplex printing.

In the case of double-sided printing, the switchback means that the conveyance is stopped in a state in which the rear end portion of the paper 21 on which one side is printed is conveyed to the discharge tray 20 (the conveyance direction indicated by arrow F in the drawing). This is an operation in which the paper 21 on which one side is printed is temporarily retracted to the discharge tray 20 and then reversely rotated and conveyed in the reverse conveyance direction indicated by an arrow E in the figure.
The guide separator 11 serving as a conveyance switching unit is disposed at a branch portion between the conveyance path 15 and the reverse conveyance path 13 and guides the paper 21 conveyed by the fixing unit 9 to the discharge tray 20.
In addition, the guide separator 11 is rotated by a driving unit 31 described later, and at the same time the discharge roller pair 10 rotates in reverse during double-sided printing, a single side conveyed in the reverse conveyance direction indicated by an arrow E in the figure. The printed paper 21 is switched to a position for guiding it to the reverse conveyance path 13.

  The stopper guide 36 as a protruding portion is made of resin and is disposed in the vicinity of the discharge roller pair 10. The stopper guide 36 adsorbs the printed paper 22 loaded on the discharge tray 20 by the static electricity or the like, with the paper 21 temporarily retracted in the discharge tray 20, and the printed paper 22 is wound on the reversely rotating discharge roller pair 10. In order to prevent this, the printed paper 22 stacked on the discharge tray 20 and the printed paper 21 on one side are linked to the drive of the drive unit 31 switching the guide separator 11 when the discharge roller pair 10 rotates in reverse. It sticks out between. The stopper guide 36 constitutes a separation mechanism 40 to be described later, and details will be described later.

The reverse conveying path 13 is a path for conveying the sheet 21 on which one side printed in the reverse conveying direction indicated by the arrow E in the reverse rotation direction by the switchback operation is printed to the image forming unit 8. Yes, from the branch portion of the conveyance path 15 and the reverse conveyance path 13, passes under the fixing unit 9 and the image forming unit 8, and is connected to the conveyance path 15 on the upstream side in the conveyance direction indicated by the arrow F in the drawing of the conveyance roller pair 5. To do. The reverse conveyance path 13 includes a plurality of conveyance roller pairs 12 that convey the paper 21.
The medium detection sensor 39 is disposed downstream of the guide separator 11 in the reverse conveyance direction indicated by an arrow E in the drawing, and detects the presence or absence of the paper 21.

The discharge tray 20 serving as a storage unit is formed on the upper surface of the printer cover 14 that is a housing of the printer 101. The discharge tray 20 stacks the printed paper 22 discharged by the discharge roller pair 10 and has one side for double-sided printing. The printed paper 21 is temporarily saved.
The discharge tray 20 includes a placement surface 20a on which the printed paper 22 is stacked and an abutting portion 20b against which one end of the printed paper 22 abuts.
The image reading apparatus 102 is arranged above the printer 101 and reads an image of a document by a light receiving element configured in a CCD (Charge Coupled Device) image sensor, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, or the like. is there.

The image reading apparatus 102 includes a scanner unit 16, a scanner cover 17, and an ADF (Auto Document Feeder) 18.
The scanner unit 16 includes an FB (FlatBed) that fixes a document on a glass table, and reads the document with a CCD image sensor or the like.
The scanner cover 17 covers the FB of the scanner unit 16.
The ADF 18 is configured integrally with the upper portion of the scanner cover 17 and conveys a plurality of pages of originals placed thereon. The scanner unit 16 reads an image of a document conveyed by the ADF 18 for each page.

FIG. 5 is an explanatory view showing the operation of the separation mechanism in the first embodiment.
Here, the configuration of the separation mechanism 40 will be described with reference to FIG.
In FIG. 5, the separation mechanism 40 performs vertical reciprocation (driving in the direction indicated by the arrow G in FIG. 6 and the arrow L in FIG. 7) by the drive unit 31 for rotating the guide separator 11. It is converted into a reciprocating motion in the horizontal direction (driving in the direction indicated by the arrow K in FIG. 6 or the arrow Q in FIG. 7) by the mechanism of the pin and pinion, and is loaded on the temporarily retracted paper 21 and the paper discharge tray 20 A stopper guide 36 is projected from the printed paper 22.

The mechanism for converting the vertical reciprocating motion into the horizontal reciprocating motion is a rack and pinion. However, the mechanism is not limited to this, and one end is attached to the drive unit 31 and the other end is engaged with the stopper guide 36. It is good also as a link mechanism etc. which match.
The separation mechanism 40 is a pinion that converts a vertical reciprocation transmitted to a link 34 attached to a drive unit 31 that reciprocates in the vertical direction and a reciprocation in the horizontal direction to a link 34 having a rack 2. The stage idle gear 35 and a stopper that is reciprocated in the horizontal direction by the two-stage idle gear 35 by having a rack and protrudes between the temporarily retracted sheet 21 and the printed sheet 22 loaded on the sheet discharge tray 20. A guide 36 is used.

The drive unit 31 as a drive means is an actuator such as a solenoid, and reciprocates in the vertical direction to rotate the guide separator 11. The drive unit 31 includes an urging member 32 such as a spring.
The drive unit 31 is turned on when the paper 21 on which one side is printed, which is transported in the transport direction indicated by the arrow F in the drawing during double-sided printing, passes through the medium detection sensor 38.
As shown in FIG. 6, the driving unit 31 that is turned on is driven in the direction indicated by the arrow G in FIG. 6. At this time, the drive unit 31 rotates the guide separator 11 in the direction indicated by the arrow H in FIG. 6, and the position where the paper 21 conveyed in the reverse conveyance direction indicated by the arrow E in FIG. 6 is guided to the reverse conveyance path 13. Switch to.

The drive unit 31 is configured to transfer the sheet 21 on which one side is printed, which is conveyed in the conveyance direction indicated by an arrow E in FIG. 7 during single-sided printing or as shown in FIG. When it passes through the medium detection sensor 39, it is turned OFF.
The drive unit 31 that has been turned off is urged by the urging member 32 in the direction indicated by the arrow L in FIG. At this time, the drive unit 31 rotates the guide separator 11 in the direction indicated by the arrow M in FIG. 7 and switches the sheet 21 conveyed by the fixing unit 9 to a position for guiding it to the discharge tray 20.
The drive generated by turning the drive unit 31 ON or OFF is transmitted to the link 34 attached to the drive unit 31.

The link 34 as a rack member is an L-shaped flat bar and is attached to the drive unit 31. The link 34 extends from a portion attached to the drive unit 31 in the direction of the two-stage idle gear 35, and has a rack 34a on a part of the extended flat bar. The rack 34 a meshes with the small gear 35 b of the two-stage idle gear 35.
The two-stage idle gear 35 as a pinion member has a large gear 35a and a small gear 35b that are integrally formed on the same axis, and the small gear 35b meshes with a rack 34a extending in the vertical direction, The gear 35a is disposed so as to mesh with the rack 36a of the stopper guide 36 extending in the horizontal direction. With this arrangement, the reciprocating motion in the vertical direction of the drive unit 31 is transmitted to the small gear 35b via the link 34, and the large gear 35a that rotates together with the small gear 35b rotates as a stopper guide. 36 is reciprocated in the horizontal direction.

In order to increase the amount of movement of the stopper guide 36 in the horizontal direction, the gear ratio between the small gear 35b and the large gear 35a of the two-stage idle gear 35 may be increased.
FIG. 2 is an explanatory view of the vicinity of the stopper guide in the first embodiment, and shows the vicinity of the stopper guide 36 when viewed from the direction indicated by the arrow A in FIG.
The discharge roller pair 10 is configured by bringing two discharge rollers into contact with each other. The discharge roller positioned below is the rotation shaft 10a and the elastic body 10b, and the discharge roller positioned above is the rotation shaft 10c and the elastic body 10d. It is comprised by.

The discharge sub-roller 37 is disposed on both sides of the elastic body 10b with the rotation shaft 10a as an axis, and has a function of pressing a part of the elastic body (not shown) to knock out the paper 21 when the paper is discharged. .
FIG. 3 is a perspective view of the stopper guide in the first embodiment, and shows a perspective view of the stopper guide 36 shown in FIGS. 1 and 2.
4 is a cross-sectional view of the vicinity of the stopper guide in the first embodiment, and is a cross-sectional view taken along the line CC in FIG. 4 shows a state (the state shown in FIG. 5) when the paper 21 on which one side is printed is temporarily retracted to the discharge tray 20.

As shown in FIG. 4, the stopper guide 36 is constituted by a protruding portion 36b, a transmission portion 36c, and a rack 36a shown in FIG. 10 and the discharge sub-roller 37.
The protruding portion 36b is located on the conveyance direction side indicated by the arrow F in the drawing with respect to the rotating shaft 10a.
Moreover, the surface in the conveyance direction shown by the arrow F in the drawing of the elastic body 10b of the discharge roller pair 10 is located on the conveyance direction side shown by the arrow F in the drawing from the protruding portion 36b.
The transmission part 36c is arrange | positioned above the rotating shaft 10a.
The rack 36a is formed in a part of the lower portion of the transmission portion 36c.

The operation of the above configuration will be described.
5, 6 and 7 are explanatory views showing the operation of the separation mechanism in the first embodiment.
The operation of the separation mechanism 40 during the switchback operation performed during double-sided printing will be described based on FIG. 1 in addition to FIGS. 5, 6, and 7.
First, as shown in FIG. 1, the sheets 21 stored in the sheet cassette 2 are separated and conveyed one by one by the sheet feeding roller 3, and one side is printed by the image forming unit 8 and the fixing unit 9.

FIG. 5 shows an operation in which the paper 21 on which one side is printed is transported in the transport direction indicated by the arrow F in the drawing and temporarily retracted to the discharge tray 20. A plurality of printed sheets 22 are stacked on the discharge tray 20.
At this time, the drive unit 31 is OFF in the guide separator 11 and is urged in the direction indicated by the arrow L in the figure by the urging member 32 and the paper 21 conveyed in the conveyance direction indicated by the arrow F in the figure. It becomes a position to guide to the discharge tray 20.
Further, the front end portion of the temporarily retracted paper 21 in the transport direction indicated by the arrow F in the drawing contacts the printed paper 22 stacked on the discharge tray 20.

Thereafter, when the sheet 21 conveyed in the conveying direction indicated by the arrow F in the drawing passes through the medium detection sensor 38, the driving unit 31 is turned on and is driven in the direction indicated by the arrow G in FIG. 19 starts the switchback operation.
As shown in FIG. 6, the temporarily retracted paper 21 is guided by the guide separator 11 rotated in the direction indicated by the arrow H in the drawing when the drive unit 31 is driven in the direction indicated by the arrow G in the drawing. It is conveyed in the reverse conveyance direction indicated by the middle arrow E.
In addition, the stopper guide 36 protrudes in the direction indicated by the arrow K in the figure by the separation mechanism 40 in conjunction with the drive unit 31 being turned on and being driven in the direction indicated by the arrow G in the figure.

Thus, when the paper 21 temporarily retracted to the discharge tray 20 is transported in the reverse transport direction, the stopper guide 36 is provided between the printed paper 22 stacked on the discharge tray 20 and the temporarily retracted paper 21. As a result of the protrusion, even if the temporarily retracted paper 21 attracts the printed paper 22 by static electricity, the temporarily retracted paper 21 and the printed paper 22 are separated from each other. It is possible to make it difficult for 22 to be caught in the discharge roller pair 10 that is rotating in the reverse direction.
Even when a large number of printed sheets 22 are stacked on the discharge tray 20, the temporarily retracted sheet 21 is more likely to attract the printed sheet 22 due to static electricity, but the temporarily retracted sheet 21 is used. Can be prevented from being caught by the paper discharge roller pair 10.

Next, as shown in FIG. 7, when the rear end portion of the paper 21 in the reverse conveyance direction indicated by the arrow E in the drawing passes through the guide separator 11, the drive unit 31 is turned off. As the drive unit 31 is driven in the direction indicated by the arrow L in the drawing by the urging force of the urging member 32, the stopper guide 36 is driven in the direction indicated by the arrow Q in the drawing by the separation mechanism 40, and is shown in FIG. Return to the previous position.
As described above, in the first embodiment, when the paper temporarily retracted to the discharge tray is transported in the reverse transport direction, between the printed paper stacked on the discharge tray and the temporarily retracted paper. Since the stopper guide is protruded at the same time, the printed sheet and the temporarily retracted sheet are separated from each other, so that the printed medium loaded on the discharge tray is rotated in the reverse rotation direction. The effect that it can suppress being caught is acquired.

In the first embodiment, when the paper 21 temporarily retracted to the discharge tray 20 is transported in the reverse transport direction, a stopper is provided between the printed medium 22 stacked on the discharge tray 20 and the paper 21 temporarily retracted. In the present embodiment, the stopper guide 36 is deformed and a member is added, so that the printed medium and the temporarily retracted medium are more reliably separated from each other.
The configuration in the vicinity of the stopper guide 46 of this embodiment will be described with reference to FIGS.
Note that parts similar to those of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. The operation near the stopper guide 46 will be described later. 8, FIG. 10 and FIG. 11 show a state (the state shown in FIG. 9) when the paper 21 on which one side is printed is temporarily retracted to the discharge tray 20.

FIG. 8 is an explanatory view of the vicinity of the stopper guide in the second embodiment, and shows the vicinity of the stopper guide 46 when viewed from the direction indicated by the arrow A in FIG.
As shown in FIG. 8, the stopper guide 46 deforms the stopper guide 36 of the first embodiment and is provided with projections 46d and 46e.
The protrusions 46d and 48e provided at the leading end in the protruding direction of the stopper guide 46 protrude between the printed sheet 22 stacked on the discharge tray 20 and the sheet 21 on which one side is printed in conjunction with the protruding operation. Plate support is installed.

The plate support as the extension protrusion is configured by plate supports 47 and 49 and plate supports 48 and 50 housed in the plate supports 47 and 49, respectively. Each plate support is made of resin.
FIG. 10 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is a cross-sectional view taken along the line DD in FIG.
In FIG. 10, the protrusion 51 is fixed to the printer 101 and is provided above the stopper guide 46.

The plate support 47 is rotatably supported at the upper end in the figure by the protrusion 51 so that the plate support 48 accommodated can be projected by sliding in the longitudinal direction.
The plate support 48 is rotatably engaged with the protrusion 46d of the stopper guide 46 on the upper end side in the drawing.
With this configuration, when the stopper guide 46 protrudes, the plate support 47 is rotated in the direction indicated by the arrow R in the figure in conjunction with the stopper guide 46 as shown in FIG. 48 slides and protrudes and contacts the inverted paper 21.

FIG. 11 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is a cross-sectional view taken along line EE in FIG.
In FIG. 11, the discharge tray 20 is provided with a protruding portion 20c obtained by deforming a part of the abutting portion 20b.
The plate support 49 is rotatably supported at the lower end in the drawing by the protrusion 20c so that the plate support 50 accommodated can be slid in the longitudinal direction to protrude.

The plate support 50 is rotatably engaged with the protrusion 46e of the stopper guide 46 on the upper end side in the drawing.
With this configuration, when the stopper guide 46 protrudes, the plate support 49 rotates in the direction indicated by the arrow T in the figure in conjunction with the stopper guide 46 as shown in FIG. 50 slides and protrudes, and comes into contact with the printed paper 22 adsorbed by static electricity to the paper 21 that is inverted.

The operation of the above configuration will be described.
9 to 17 are explanatory views showing the operation of the separation mechanism in the second embodiment and sectional views showing the operation in the vicinity of the stopper guide in the second embodiment.
The operation of the stopper guide 46 and the plate supports 47, 48, 49, 50 during the switchback operation performed during duplex printing will be described with reference to FIGS. Since the operation other than the stopper guide 46 and the plate supports 47, 48, 49, 50 is the same as that of the first embodiment, the description thereof is omitted.

FIG. 9 is an explanatory view showing the operation of the separation mechanism in the second embodiment.
As shown in FIG. 9, the sheet 21 on which one side is printed is transported in the transport direction indicated by the arrow F in the drawing, and the operation of temporarily retracting the sheet 21 to the discharge tray 20 is shown. A plurality of printed sheets 22 are stacked on the discharge tray 20.
10 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is a DD cross-sectional view shown in FIG. 8 in the state of FIG.
As shown in FIG. 10, since the stopper guide 46 does not protrude, the plate support 48 is stored in the plate support 47.

FIG. 11 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is an EE cross-sectional view in the state of FIG.
As shown in FIG. 11, since the stopper guide 46 does not protrude, the plate support 50 is housed in the plate support 49.
FIG. 12 is an explanatory view showing the operation of the separation mechanism in the second embodiment.
As shown in FIG. 12, the temporarily retracted paper 21 is guided by the guide separator 11 rotated in the direction indicated by the arrow H in the drawing when the drive unit 31 is driven in the direction indicated by the arrow G in the drawing. It is conveyed in the reverse conveyance direction indicated by the middle arrow E. Further, in conjunction with the drive unit 31 being turned ON and being driven in the direction indicated by the arrow G in the drawing, the stopper guide 46 is projected in the direction indicated by the arrow K in the drawing by the separation mechanism 40.

FIG. 13 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is a DD cross-sectional view in the state of FIG.
As shown in FIG. 13, the plate support 48 slides in the direction indicated by the arrow S in the figure while the plate support 47 rotates in the direction indicated by the arrow R in the figure in conjunction with the movement of the stopper guide 46 protruding. The paper 21 that protrudes and is reversed is brought into contact.
FIG. 14 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is an EE cross-sectional view in the state of FIG.
As shown in FIG. 14, the plate support 50 slides in the direction indicated by the arrow V in the figure while the plate support 49 rotates in the direction indicated by the arrow T in the figure in conjunction with the movement of the stopper guide 46 protruding. The printed paper 22 is made to come into contact with the paper 21 protruding and inverted by static electricity.

  In this way, when the paper 21 temporarily retracted to the discharge tray 20 is transported in the reverse transport direction, the stopper guide 46 and the printed paper 22 stacked on the discharge tray 20 and the temporarily retracted paper 21 are Since the plate supports 48 and 50 are projected in conjunction with each other, even if the temporarily retracted paper 21 adsorbs the printed paper 22 due to static electricity, the plate support 48 contacts the temporarily retracted paper 21. Since the plate support 50 is in contact with the printed paper 22 and the temporarily retracted paper 21 and the printed paper 22 are separated from each other, the printed paper 22 is caught in the discharge roller pair 10 rotating in the reverse direction. It can be made difficult.

FIG. 15 is an explanatory view showing the operation of the separation mechanism in the second embodiment.
As shown in FIG. 15, when the rear end portion of the paper 21 in the reverse conveyance direction indicated by the arrow E in the drawing passes through the guide separator 11, the drive unit 31 is turned off. As the drive unit 31 is driven in the direction indicated by the arrow L in the figure by the urging force of the urging member 32, the stopper guide 46 is driven in the direction indicated by the arrow Q in the figure by the separation mechanism 40, and is shown in FIG. Return to the previous position.
FIG. 16 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is a DD cross-sectional view in the state of FIG.

As shown in FIG. 16, the plate support 48 is slid in the direction of the arrow W in the drawing and accommodated in the plate support 47 in conjunction with the operation of the stopper guide 46 being driven in the direction of the arrow Q in the drawing. Rotates in the direction of arrow X in the figure, and returns to the state shown in FIG.
FIG. 17 is a cross-sectional view showing the operation in the vicinity of the stopper guide in the second embodiment, and is an EE cross-sectional view in the state of FIG.
As shown in FIG. 17, the plate support 50 is slid in the direction of the arrow Y in the drawing and accommodated in the plate support 49 in conjunction with the operation in which the stopper guide 46 is driven in the direction of the arrow Q in the drawing. Rotates in the direction of arrow Z in the figure, and returns to the state shown in FIG.

As described above, in the second embodiment, in addition to the effect of the first embodiment, the plate support attached to the stopper guide protrudes in conjunction with the protruding operation of the stopper guide. Since the temporarily retracted paper 21 and the printed paper 22 are separated from each other more reliably, the printed medium loaded on the discharge tray is prevented from being caught in the reversely rotating discharge roller pair. The effect that it can be obtained.
In the first and second embodiments, the stopper guide and the plate support are made of resin. However, the stopper guide and the plate support are not limited to these, and are made of a conductive material such as metal. In this way, the static electricity may be removed by making contact with the temporarily retracted paper and the printed paper so that the paper temporarily retracting the printed paper is not attracted.

Further, the stopper guide is interlocked with the drive unit for switching the guide separator. However, the present invention is not limited to this, and a motor (not shown) that rotates the discharge roller pair forward and backward is provided. It may be linked to the drive for rotating the pair in the reverse direction, or may be operated by another drive unit.
Furthermore, the stopper guide is protruded simultaneously with the reverse rotation of the discharge roller pair. However, the present invention is not limited to this, and the stopper guide may be protruded before the discharge roller pair rotates reversely.
In the first embodiment and the second embodiment, the image forming apparatus provided in the composite apparatus has been described as an example. However, the present invention is not limited thereto, and the image forming apparatus can be provided in a printer, a facsimile machine, or the like.

10, 19 Discharge roller pair 11 Guide separator 13 Reverse conveyance path 15 Conveyance path 20 Discharge tray 21 Paper 22 Printed paper 31 Drive unit 36, 46 Stopper guide 47, 48, 49, 50 Plate support 100 Composite device 101 Printer 102 Image reading apparatus

Claims (10)

A storage unit that stacks printed media and temporarily retracts a medium on which one side is printed during duplex printing;
During double-sided printing, the conveyance is stopped in a state where the rear end in the direction of conveying the medium on which the one side is printed to the accommodation unit is sandwiched, and the medium on which the one side is printed is temporarily retracted to the accommodation unit. A conveying means for carrying out reverse rotation from
An image forming apparatus comprising: a protruding portion that protrudes between a medium stacked in the housing portion and a medium on which the one side is printed when the conveying unit rotates in the reverse direction. A reverse conveying path which is a path for conveying the medium on which the one side is printed by reverse rotation of the conveying means;
A transport switching unit that switches to a position that guides the medium on which the one side is printed to the reverse transport path at the same time as the transport unit rotates in reverse;
Drive means for switching the conveyance switching unit;
The image forming apparatus according to claim 1, wherein the protruding portion protrudes in conjunction with a drive in which the driving unit switches the conveyance switching portion. A rack member attached to the drive means;
A pinion member meshing with the rack member,
3. The projecting portion formed in a part of the rack and meshing with the pinion member is interlocked with the switching drive of the driving means transmitted by a rack-and-pinion configuration. Image forming apparatus. A link mechanism in which one end is attached to the driving means and the other end engages with the protrusion;
The image forming apparatus according to claim 2, wherein the projecting portion is interlocked by transmitting the switching drive of the driving unit by the link mechanism. Rotation drive means for rotating the transport means forward and backward,
The image forming apparatus according to claim 1, wherein the protrusion is interlocked with a drive in which the rotation driving unit rotates the transport unit in a reverse direction. A rack member attached to the rotation driving means;
A pinion member meshing with the rack member,
The protruding portion, which is partially formed with a rack and meshes with the pinion member, is interlocked with the rotation driving means that transmits the driving means for reversely rotating the conveying means by a rack-and-pinion configuration. The image forming apparatus according to claim 5. A link mechanism in which one end is attached to the rotation driving means and the other end engages with the protrusion;
6. The image forming apparatus according to claim 5, wherein the protrusion is interlocked with the rotation of the rotation driving unit transmitted by the link mechanism by the link mechanism.   The leading end of the projecting portion in the projecting direction has an extended projecting portion projecting between the medium stacked on the storage unit and the medium on which the one side is printed in conjunction with the projecting operation. The image forming apparatus according to claim 7.   The image forming apparatus according to claim 8, wherein the extension protrusion is formed of a conductive member.   The image forming apparatus according to claim 1, wherein the protruding portion is formed of a conductive member.

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