JPH0551158A - Sheet reversing device - Google Patents

Abstract

PURPOSE:To provide a sheet reversing device capable of corresponding also to a high-speed machine type by providing an opening/closing means, energized in the direction of closing an inlet part and a reversing path, in a position where the inlet part and an outlet part join the reversing path so as to communicate the inlet part with the reversing path at the sheet feed-in time and to guide the sheet to the outlet part at the delivery time. CONSTITUTION:When the rear end of a sheet fed in from an inlet part formed of a pair of rollers 121, 122 is taken into a reversing path formed of guide plates 163, 164, the carrier direction is reversed so as to feed the sheet, with the rear end side thereof as the head, to an outlet part formed of a pair of rollers 121, 123 from the reversing path. In a position where the inlet part and outlet part join the reversing path, there is provided an opening/closing member 153 energized in the direction of closing the inlet part and reversing path so that the member 153 is pushed up by the sheet tip at the feed-in time of the sheet to communicate the inlet part with the reversing path and that the sheet is guided to the outlet part by the member 153 at the delivery time. This results in obtaining a sheet reversing device capable of corresponding also to a high- speed machine type with short sheet intervals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet reversing device. The device of the present invention is used, for example, in a printer or the like to switch between printing a printed sheet face-up on a sheet discharge tray or face-down a sheet discharge tray. it can.

[0002]

2. Description of the Related Art (1) A switchback type sheet reversing device is provided. This is because the sheet sent from the entrance to the reversing path is conveyed as it is, and when the trailing edge of the sheet is completely taken into the reversing path, the conveying direction is reversed and the trailing edge side is reversed. A device for feeding a sheet from a path to an exit section, which is a common driving roll for feeding a sheet from an entrance section to a reverse path and feeding a sheet from a reverse path to an exit section.
It is a device that executes by using LA.

That is, in the above-mentioned paper reversing device, the paper is fed by the main roller and the driven roller on the inlet side pressed against the main roller.
It is sent from the entrance to the inversion path by the la. Also,
After the conveyance direction is reversed as described above, the trailing edge of the sheet is guided by the rotation of the driving roller to move the driving roller.
It is sent out from the reversing path to the outlet portion by the la and the driven roller on the outlet side pressed against the la.

The entrance portion is, for example, a portion for receiving the paper fed from an image fixing device such as a printer, and the exit portion is, for example, the portion leading to a discharge tray for storing printed paper. Is. Further, the inlet portion and the outlet portion are arranged adjacent to each other so as to join at one end of the inversion path.

(2) When the sheet fed into the reversing path from the entrance portion is conveyed as it is, and the rear end of the sheet is completely taken into the reversing path, the conveying direction is reversed and the rear end side becomes the leading end. There is provided a sheet reversing device for feeding the reversing path from the reversing path to the exit part, in which a switching lever is arranged at the confluence of the entrance part and the exit part.

The above-mentioned switching lever is a sheet guide function of the driving roller in the above-mentioned switchback system (after reversing the conveying direction, the rear end of the sheet is moved to the outlet side by the rotation of the driving roller. This is a member for realizing the function of guiding). For example, when feeding a sheet from the inlet to the reversing path, the switching lever is set at a position where the inlet and the reversing path communicate with each other. Further, when the sheet is sent from the reversing path to the exit section, the switching lever is set at a position where the reversing path communicates with the exit section.

[0007]

In the sheet reversing device of (1), when the trailing edge of the sheet is guided to the exit side by the rotation of the driving roller after the reverse of the conveying direction, The trailing edge is curled or bent, which tends to cause a jam.

In the paper reversing device of the above (2), the switching lever is
The arrangement makes the mechanism complicated and the device cannot be downsized. Further, since switching by the switching lever requires a certain amount of time, it cannot be supported by a high-speed model having a short paper interval. Further, precision is required in the mounting position of the switching lever. That is, if there is an attachment error, when the trailing edge of the sheet is guided to the exit side by the switching lever after the reverse rotation of the conveying direction, the trailing edge is caught by the leading edge of the switching lever, and a jam occurs. It tends to be the cause.

The present invention has been made in view of the above circumstances, and realizes a sheet reversing device with a simple mechanism that can be downsized, and enhances its reliability.
The purpose is to support high-speed models with short paper intervals.

[0010]

According to the first aspect of the present invention, a sheet fed from an entrance portion to a reversing path is conveyed in a feeding direction, and a trailing end of the sheet passes through the entrance portion to enter the reversing path. In the sheet reversing device which, when taken in, reverses the conveying direction and feeds the rear end side of the sheet from the reversing path to the exit section, the entrance section and the exit section are connected to one end of the reversing path. Are arranged adjacent to each other so as to diverge from the reversing path in the section, and are pressed by the sheet fed into the reversing path from the entrance section at the branching position, the entrance section and the reversing path. An opening / closing member that communicates with the opening / closing member, and by providing the opening / closing member with a biasing unit that constantly biases the opening / closing member in a direction of closing the inlet portion and the reversing path, When the paper is sent to the outlet, the paper is put on the opening / closing member. It is obtained so as to guide to the outlet side of me.

In a second aspect of the present invention, in the first aspect of the invention, the reversing path is configured to be openable so that paper can be removed from the outside, and the opening / closing member is provided with the reversing path. A retracting mechanism for retracting the opening / closing member from the branch position is provided in association with the opening operation.

In a third aspect of the present invention based on the first aspect, the tip end side of the opening / closing member is formed in a comb tooth shape, and the comb tooth is provided at a portion of the inversion path corresponding to the opening / closing member. When a sheet is sent out from the reversing path to the outlet section by forming a recess for receiving the sheet, the tip of the comb tooth is buried so as to engage with the recess, and the sheet is opened by the opening / closing member. It is designed to guide the department.

[0013]

The sheet fed from the entrance portion is fed into the reversing path while pushing up the opening / closing member at the leading end thereof to make the entrance portion communicate with the reversing path. The trailing edge of the paper passes through the entrance,
When the opening / closing member is completely taken into the reversing path, the opening / closing member returns to the original position (the position that closes the inlet portion and the reversing path) by the urging force of the urging means, and the conveyance direction of the sheet is reversed. In this way, the initial trailing edge of the sheet that has started to be conveyed in the reverse direction is guided to the exit side by the opening / closing member that has returned to the original position, and is sent out from the reversing path.

[0014]

EXAMPLES Examples of the present invention will be described below. [1] Outline of Mechanism of Copying Machine FIG. 1 is a schematic diagram showing the entire mechanism of an electrophotographic copying machine equipped with a sheet reversing device 100 according to an embodiment.

In the copying machine shown in the figure, the image reflected light from the original placed on the original table is directed by the optical system 10 to the surface of the photosensitive drum 31 through the path indicated by the dashed line arrow 11. It is guided and imaged on its surface. Photoconductor drum 31
Is rotated in the direction of arrow a at a constant speed, and the charging
The jar 32 is uniformly charged in front of the image forming position.

Therefore, by the image formation of the image reflected light,
The surface of the photoconductor drum 31 has a pattern corresponding to the original image.
Electrostatic latent image is formed. The electrostatic latent image is then toner-developed by the developing device 33 and visualized. Also,
The toner image is transferred onto the paper at the position of the transfer charger 34, and the paper is transferred to the photosensitive drum at the position of the separation charger 35.
Separated from 31.

In the above, the paper is the upper paper feed cassette.
After being pulled out from 51 by the paper feed roller 52, only one sheet is taken out by the separating roller pair 53, and further conveyed by the conveying roller group 57 to the position of the timing roller pair 58. Then, at that position, it is temporarily stopped. Alternatively, after the sheet is drawn from the lower sheet feeding cassette 54 by the sheet feeding roller 55, only one sheet is taken out by the sheet separating roller pair 56, and the timing roller pair 58 is separated by the conveying roller group 57. It is conveyed to a position and temporarily stopped at that position.

As described above, the sheet stopped at the position of the timing roller pair 58 is next subjected to the photosensitive drum 31 at a predetermined timing synchronized with the image front end of the toner image on the photosensitive drum 31. The sheet is sent out between the transfer charger 34 and the transfer processing described above. After that, it is conveyed to the fixing device 60 by the conveyor belt 59 and subjected to image fixing processing by thermocompression bonding. The fixing device 60 is composed of a heating roller 62 with a built-in heat lamp 61 and a pressure roller 63 having an elastic material on its surface. The toner particles are melt-welded onto a sheet. Device.

The sheet thus subjected to the image fixing process passes through the sheet reversing device 100, and then the pair of discharge rollers 141 and 142.
Thus, as indicated by arrow b, the sheet is discharged face-up or face-down onto a discharge tray (not shown) outside the machine. Here, the face-up means a state in which the image forming surface is on the upper side, and the face-down means a state in which the image forming surface is in the lower side.

For example, at the time of face-up, the transport roll is
The sheet conveyed to the right in FIG. 1 by the pair of rollers 101 and 102 is guided by the upper surface of the sheet passing direction switching claw 151, and the pair of conveying rollers 11 and 102.
1, 112, the paper is conveyed to the discharge roller pair 141, 142 by the conveyance roller pair 111, 112, and then is discharged onto the paper discharge tray outside the apparatus with the image forming surface facing upward.

On the other hand, at the time of face-down, the paper is guided to the lower surface of the paper passing direction switching claw 151, and the pair of transport rollers 12 are fed.
1, 122, and is fed into the inversion path constituted by the guide plates 163, 164 (FIG. 2) by the pair of transport rollers 121, 122.
Further, the sheet fed into the reversing path is conveyed as it is in the feeding direction (downward) by the conveying roller pair 131, 132 until the rear end passes through the position of the conveying roller pair 121, 122. Next, the trailing edge of the paper is set to the above-mentioned transport roller pair 121,12.
When the sheet sensor 157 (FIG. 2) detects the passage after passing the position 2, the reverse rotation drive of the pair of transport rollers 131 and 132 is started. As a result, the sheet is guided to the right side surface of the sheet feeding direction switching claw 153 in the figure and reaches the conveyance roller pair 121, 123, and the conveyance is continued by the conveyance roller pair 121, 123. , Furthermore, transport roller pair 11
After being conveyed to the pair of discharge rollers 141 and 142 through 1,113, the sheet is discharged onto a sheet discharge tray outside the apparatus with the image forming surface facing down.

[2] Mechanism and Action of Paper Reversing Device 100 FIG. 2 is a diagram schematically showing the details of a cross section near the paper reversing device 100 according to the first embodiment. Paper reversing device 100
Is a pair of conveyor rollers 121, 122 that form the entrance part of the claims.
And guide plates 163 and 164 forming the reversing path of the claims, conveying roller pairs 121 and 123 forming the outlets of the claims, and sheet passing direction switching claws 153 which are the opening and closing members of the claims.

[2-1] Face-up At the time of face-up, the solenoid 151a is turned off, so that the sheet passing direction switching claw 151 is in the solid line position in the figure. The driving roller 111, which is a driving roller for the pair of conveying rollers 111 and 112, is rotationally driven in the direction of arrow e in the figure.

The sheet sent out from the fixing device 60 as described above has a pair of conveying rollers 101 and 102 composed of a driving roller 101 and a driven roller 102 pressed against the driving roller 101.
Guided between the guide plates 161, 162, and then the guide plates
A pair of conveying rollers 111 and 112, which are guided by the lower surface of 161 and the upper surface of the sheet-passing direction switching claw 151, and are composed of a driving roller 111 and a driven roller 112 pressed against the driving roller 111. Leading to. Further, the guide roller pair 111, 112 is used to guide the guide plate.
166, 167, and then the pair of discharge rollers 141,
It is discharged out of the machine by 142.

[2-2] Face Down At the time of face down, the solenoid 151a is turned on, so that the sheet passing direction switching claw 151 is at the position indicated by the chain double-dashed line in the figure. The driving roller 111, which is a driving roller for the pair of conveying rollers 111 and 113, is rotationally driven in the direction of arrow f in the figure. Further, the carrier roller pair 121, 122 and the carrier roller pair 121, 12
A driving roller 121, which is a common driving roller of 3, is rotationally driven in the direction of the arrow in the figure.

The sheet sent from the fixing device 60 as described above is guided by the pair of conveying rollers 101 and 102 to the guide plates 161 and 162.
After being guided in between, the lower surface of the paper feed direction switching pawl 151 and the guide plate
It is guided by the upper surface of 162 to reach the pair of conveying rollers 121 and 122, and further conveyed by the pair of conveying rollers 111 and 112, and the leading end of the sheet passing direction switching claw 153, which is the opening / closing member of the claims, is fed to the sheet. While being pushed away by the tip, it is guided between the guide plates 163 and 164.

Here, the paper passing direction switching claw 153 is constantly given a biasing force in the arrow h direction by a coil spring 153b (FIG. 3). Therefore, as shown in FIG. 4, the leading end side of the sheet P pushes away the lower end side of the sheet passing direction switching claw 153 against the biasing force h, and as described above,
Guided between 163,164. In other words, the magnitude of the biasing force h is such that it is pushed away by the paper P.

In this way, the sheet guided between the guide plates 163 and 164 is the driving roller 131 and the driving roller 131.
The conveyance roller pair 131, 132 composed of the driven roller 132 pressed against the roller 131 keeps the conveyance downward in the figure. In other words, initially, the driving roller 131 is rotationally driven in the direction of arrow c in the figure.

Next, when the trailing edge of the sheet passes the position of the actuator 157a and the passage is detected by the sheet sensor 157, the rotation direction of the driving roller 131 is indicated by the arrow in the figure.
Reversed in the direction of d. As a result, the transport direction of the paper P is also reversed, and the transport of the paper P upward is started. Thus, as shown in FIG. 5, the original rear end side of the sheet P contacts the right side surface of the sheet passing direction switching claw 153 in the figure.

As described above, when the initial rear end side of the sheet P contacts the right side surface of the sheet passing direction switching claw 153 in the figure, the sheet P is
It is guided to the right side surface of the sheet passing direction switching claw 153 and conveyed to the side of the conveying roller pair 121, 123, and further, the conveying roller pair 121, 123.
While being conveyed by 123, it is guided by the right side surface of the sheet passing guide claw 155 in the figure and the guide plate 166, and reaches a pair of conveying rollers 111, 113 composed of a driving roller 111 and a driven roller 113. ..

In the above, the lower end side of the guide plate 166 is
The bent portion 166a is formed at a substantially right angle. This is for squeezing and correcting the curl of the paper caused by the thermocompression bonding in the fixing device 60. In other words, if the curl is not corrected, there is a risk that the later ejected paper may sneak under the previously ejected paper on the ejection tray (not shown). To do. For this reason, when face down, the conveyor roller pair 11
Tension is applied to the paper by making the conveyance speed by 1,113 slightly higher than the conveyance speed by the conveyance roller pair 121,123 (eg, 1.2 times). A torque limiter is attached to the driving mechanism of the driving roller 111 to prevent excessive tension.

In this way, the sheets that have reached the pair of transport rollers 111, 113 are guided by the pair of transport rollers 111, 113 by the guide plates 166, 16.
After being introduced into
2 and the paper is ejected onto the paper ejection tray outside the machine with the image forming surface facing down.

[3] Details of Paper-Passing Direction Switching Claw (Opening / Closing Member) 153 FIG. 3 is a perspective view of the vicinity of the paper-passing direction switching claw 153 as viewed from the right side of FIG. As shown in the figure, the paper passing direction switching pawl 153
At the tip (lower end in FIG. 2) of the convex portion 153d and the concave portion 153c,
The teeth are alternately formed in a comb shape. In addition, the guide plate 163 is provided with a concave portion at a portion to which the convex portion 153d is to contact.
163b is formed, and ribs 163a are formed between the recesses 163b.

Further, the paper passing direction switching claw 153 is applied with a biasing force in the direction of the arrow (the above biasing force h) by a coil spring 153b. Therefore, when there is no paper between the paper passing direction switching claw 153 and the guide plate 163,
The comb-teeth-shaped tip of the paper passing direction switching claw 153 and the guide plate 163.
The respective concave portions 163b and the respective ribs 163a mesh with each other, and the comb-teeth-shaped tip portion is embedded in the concave portion 163b.

Therefore, as shown in FIG. 5, when the paper P is conveyed from below and comes into contact with the paper passage direction switching claw 153, the contact portion of the paper P (the above-mentioned initial rear The edge P is prevented from slipping into the gap between the sheet passing direction switching claw 153 and the guide plate 163 (inlet side of claim), and the sheet P is surely transferred to the pair of transport rollers 121 and 123 (outlet of claim). To the department).

Further, as shown in FIG. 4, the paper P
Is conveyed downward from the pair of conveying rollers 121, 122 (the inlet side in the claims), and its leading end abuts on the left side surface of the sheet passing direction switching claw 153 in the figure to cause the sheet passing direction switching claw 153 to move. When the tip of the sheet is pushed into the inversion path (between the guide plates 163 and 164), the contact area between the comb-teeth-shaped tip of the sheet passing direction switching claw 153 and the sheet P is small, so that the friction force and The generation of static electricity is suppressed to a level at which there is no problem with the above approach.

In FIG. 3, the paper passing direction switching claw 153 is shown.
The member 153f attached to the front end of the rotating shaft 153a through a mounting tool 153e coaxial with the rotating shaft 153a is a paper passage direction switching claw when the guide plate 164 forming the reversing path is opened.
This is a member for rotating and retracting the tip end portion of 153 (on the side of the convex portion 153d) as indicated by arrow j in FIG.

[4] Reverse Path Opening Mechanism Next, the reverse path opening mechanism will be described with reference to FIGS. The reversing path opening mechanism is a mechanism used when removing jammed paper from the outside. Figure 6 shows the guide plate 16
FIG. 7 shows a state in which 4 is opened, and FIG. 7 shows a rotation state of the sheet passing direction switching claw 153 at the time of opening.

That is, the support mechanism of the rotary shaft 153a of the paper passing direction switching claw 153 is constructed so as to be movable integrally with the support mechanism of the guide plate 164. Therefore, in order to open the inversion path,
Guide plate 164 along guide plate 165 to the right of the figure (arrow k
(Direction), the paper passing direction switching claw 153 rotatably supported by the rotary shaft 153a also moves integrally in the same direction. That is, the pair of transport rollers 121 and 122, the transport rollers
Evacuated from the vicinity of La pair 121,123.

At this time, as shown in FIG. 7, the member 153f attached to the end of the paper-passage direction switching claw is pushed by the lower surface of the guide plate 165a and rotated in the direction of arrow j, Along with this, the tip of the paper-passing direction switching claw (on the comb teeth 153d side) also rotates in the direction of arrow j as shown in FIG. 6 and is retracted to the guide plate 164 side. In this way, when the reversing path is opened, the sheet passing direction switching claw 153 is retracted to a position where it does not hinder the removal of the sheet and to a state where it does not hinder the removal of the sheet.

[5] Second Embodiment Next, referring to FIG. 8, the first embodiment will be described with reference to the second embodiment.
The difference from the embodiment described above will be mainly described. In the first embodiment, the inlet portion of the claims is constituted by the pair of conveying rollers 121, 122, and the outlet portion of the claims is constituted by the pair of conveying rollers 121, 123. In other words, the inlet part and the outlet part of the claims have a common driving roller 121.

On the other hand, in the second embodiment, the inlet part and the outlet part in the claims are each constituted by a pair of guide plates. Further, a configuration is adopted in which the sheet is conveyed on the inlet side by the conveying roller pair 181, 182, and the sheet is conveyed on the outlet side by the conveying roller pair 183, 184. The present invention can also be achieved by such a configuration.

[0043]

As described above, according to the present invention, when the trailing edge of the fed sheet is taken into the reversing path, the conveying direction is reversed,
In the paper reversing device that feeds the rear end side to the exit part from the reversing path, at the position where the entrance part and the exit part meet,
An opening / closing member that is always urged in a direction to close the inlet portion and the reversing path is provided, and when the paper is fed, the opening / closing member is pushed up by the leading edge of the paper to communicate the inlet portion and the reversing path, and when the paper is sent out. A device that guides a sheet to an exit portion by the opening / closing member.

According to the present invention, at the time of feeding, the opening / closing member is pushed up by the front end of the paper to communicate the entrance portion with the reversing path, and the paper is sent from the entrance portion to the reversing path. When the trailing edge of the sheet is fed into the reversing path, the opening / closing member is returned to the original position (the position that closes the entrance and the reversing path) by the urging force. In addition, the conveyance direction of the paper is reversed and the paper is started to be sent out. Therefore, the original trailing edge of the sheet is guided to the exit side by the opening / closing member that has been returned to the original position, and is sent out from the reversing path. As described above, the present invention realizes a paper reversing device having a high reliability and a high speed model with a short paper interval by a simple mechanism.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a copying machine equipped with a sheet reversing device according to an embodiment.

FIG. 2 is an explanatory view schematically showing a cross section of the paper reversing device according to the first embodiment.

FIG. 3 is a perspective view showing the vicinity of an opening / closing member of the paper reversing device.

FIG. 4 is an explanatory diagram showing a sheet conveyance state (forward direction) in the sheet reversing device.

FIG. 5 is an explanatory diagram showing a sheet conveyance state (reverse direction) in the sheet reversing device.

FIG. 6 is an explanatory diagram showing a state in which the reversing path is opened in the paper reversing device.

FIG. 7 is an explanatory diagram showing a state of the opening / closing member when the reversing path is opened in the sheet reversing device.

FIG. 8 is an explanatory diagram schematically showing a cross section of a paper reversing device according to a second embodiment.

[Explanation of symbols]

100 paper reversing device, 153 paper-passing direction switching claw (opening / closing member), 151 paper-passing direction switching claw, 155 paper-passing guide claw, 157 paper detection sensor, 157a paper detection sensor actuator,

Claims (3)

[Claims] 1. When a sheet fed into an inversion path from an entrance portion is conveyed in an infeed direction and the trailing edge of the sheet passes through the entrance portion and is taken into the inversion path, the conveyance direction is reversed. In a paper reversing device that feeds the rear end side of the paper from the reversing path to the exit section, the inlet section and the exit section are branched from the reversing path at one end of the reversing path. As described above, an opening / closing member that is arranged adjacent to each other and that communicates between the inlet section and the reversing path by being pressed by the sheet fed into the reversing path from the inlet section is disposed at the branch position. The opening / closing member is provided with an urging means for constantly urging the opening / closing member in a direction of closing the inlet portion and the reversing path, whereby a sheet is fed from the reversing path to the outlet portion. When the paper is sent out, the paper is Sheet reversing apparatus designed to guide the outlet side. 2. When the sheet fed from the entrance to the reversing path is conveyed in the feeding direction, and the trailing edge of the sheet passes through the entrance and is taken into the reversing path, the conveying direction is reversed. In a paper reversing device that feeds the rear end side of the paper from the reversing path to the exit section, the inlet section and the exit section are branched from the reversing path at one end of the reversing path. As described above, the reversing path is configured to be openable so that the paper can be removed from the outside, and the reversing path is fed from the inlet portion to the reversing path. An opening / closing member is provided which is pressed against the coming sheet to connect the inlet portion and the reversing path, and the opening / closing member is always urged in the direction of closing the inlet portion and the reversing path. Urging means and a movement for opening the reversal path. A retracting mechanism for retracting the opening / closing member from the branching position is provided in association with the guide, so that when the sheet is sent from the reversing path to the outlet, the sheet is guided to the outlet by the opening / closing member. In addition, when the reversing path is operated for the opening, the sheet reversing device is configured to retract the opening / closing member from the branch position in conjunction with the operation. 3. When the sheet fed from the entrance to the reversing path is conveyed in the feeding direction, and the trailing edge of the sheet passes through the entrance and is taken into the reversing path, the conveying direction is reversed. In a paper reversing device that feeds the rear end side of the paper from the reversing path to the exit section, the inlet section and the exit section are branched from the reversing path at one end of the reversing path. Are arranged adjacent to each other, and at the branching position, a comb-teeth shape that presses the sheet fed into the reversing path from the entrance section to communicate the entrance section with the reversing path. An opening / closing member is provided, and the opening / closing member is provided with a biasing unit that constantly biases the opening / closing member in a direction of closing the inlet portion and the reversing passage, and corresponds to the opening / closing member of the reversing passage. In the portion to be formed, a concave portion corresponding to the comb tooth is formed to receive the comb tooth. As a result, when the paper is sent from the inversion path to the outlet, the tip of the comb tooth is embedded so as to engage with the recess, and the paper is guided to the outlet by the opening / closing member. Paper reversing device.