JPH11189362A - Sheet feeder and sheet processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a flapper properly against malfunction with a drive means of a small capacity, such as a motor and a solenoid, by reducing the load acting on the flapper from a sheet stopper. SOLUTION: A flapper 118 is positioned to lead a sheet S up. In this state, a sheet stopper 119 adapted to turn on its pivot 121 is pressed counterclockwise by the flapper 118 and also clockwise by the function of its weight part 119b. This sheet stopper 119 thus closes the passage that leads to the upstream section of a path 112.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus provided in a sheet processing apparatus for performing a predetermined process on sheets fed one by one.

Note that the sheet processing apparatus referred to here includes, for example, a copying machine, a printer, a facsimile, and the like that form an image on a sheet fed one by one.

[0003]

2. Description of the Related Art FIG. 7 shows an overall schematic configuration of a laser beam printer (sheet processing apparatus) provided with a sheet conveying apparatus 100A to which the present invention is applied. In addition,
The sheet conveying device 100A here is for enabling printed sheets to be discharged either face-up discharge or face-down discharge.

First, the overall configuration of the printer will be briefly described.

When a print start signal is input from a host computer (not shown), the laser scanner 10
1 emits a laser beam L based on the image information sent from the host computer. The laser light L is reflected by the folding mirror 111 and is irradiated on the photosensitive drum 102 rotating clockwise. As a result, an electrostatic latent image of image information is formed on the photosensitive drum 102,
This electrostatic latent image is developed by a toner developing device (not shown).

On the other hand, in response to the input of the print start signal, the sheets S stacked and stored in the cassette 103 are sequentially fed out from the top sheet by the feeding roller 104 rotating in the counterclockwise direction. Then, the sheets S fed out from the cassette 103 are separated and fed one by one by a separation feeding roller pair 105.

The sheet S fed by the separation feeding roller pair 105 is sent by the conveyance roller pair 106 to the registration roller pair 107 in a rotation stopped state. The sheet S stops moving when the leading end of the sheet S hits the nip of the pair of registration rollers 107 to form a predetermined amount of loop. By forming this loop, the skewed state of the sheet is corrected.

The sheet S whose skew has been corrected is sent to a transfer portion between the photosensitive drum 102 and the transfer roller 108 by a registration roller pair 107 which starts rotating at a predetermined timing.

The toner image on the photosensitive drum 102 is transferred to the sheet S passing through the transfer section by the transfer roller 108. The sheet S to which the toner image has been transferred after passing through the transfer unit is sent to the fixing roller pair 110 by the transport belt 109.

The sheet S passing through the nip of the fixing roller pair 110 is heated and pressed. As a result, the toner image in the unfixed state is fixed on the sheet surface.

The sheet S that has passed the fixing roller pair 110 and has been subjected to the fixing process is discharged onto a discharge tray 124 outside the apparatus by the sheet conveying device 100A. The sheet conveyance device 100A discharges the sheet S by either face-up discharge or face-down discharge.

Next, the configuration of the main part of the conventional sheet conveying apparatus 100A will be described in detail with reference to FIGS.

The sheet conveying apparatus 100A includes a first path 112 that guides the sheet S passing through the fixing roller pair 110 in a substantially horizontal state toward the sheet discharge tray 124 (the direction of arrow P1, the first direction). , The second path 113 branching from the middle of the first path 112 in a substantially vertical downward direction.
And the third path 11 connected to the second path 113
Four.

The second pass 113 includes a fixing roller pair 110
After guiding the sheet S that has passed through in the downward direction (the direction of the arrow P2, the second direction), and then upward (the direction of the arrow P3, the third direction)
To reverse the front and back surfaces of the sheet S. The third path 114 is a path for guiding the sheet S guided downward by the second path 113 in the horizontal direction and temporarily holding the sheet S.

A transport roller pair 115 is provided at the upstream end of the first path 112, and a discharge roller pair 116 is provided at the downstream end. At the downstream end of the second path 113, a pair of reversing rollers 117 is provided.

A flapper (conveying direction changing means) 118 for changing the conveying direction of the sheet S is provided at a portion where the second path 113 branches. Further, a sheet stopper (sheet intrusion prevention means) is provided at an upstream portion of the second path 113 to prevent the sheet S moving upward in the second path 113 from moving toward the upstream side of the first path 112.
119 are installed.

The flapper 118 is rotatable about a rotation shaft 120, and is provided with a driving means (not shown) (for example,
Driven by a motor or a solenoid. The flapper 118 has guide surfaces 118a, 118b, 118c.
have.

The sheet stopper 119 is rotatable about a support shaft 121 outside the path 113, and is urged clockwise by a coil spring 122. Usually, the stopper 123 is in contact with the guide member 113a to restrict the rotation. At this time, the portion protruding into the path 113 is shaped like a letter.

FIG. 8 shows the state of the flapper 118 and the sheet stopper 119 when the face-up discharge mode is selected.

At this time, the flapper 118 is
a is substantially parallel to the guide member 112a, and the first path 112 is opened and the second path 113 is closed. The sheet stopper 119 is in a state where the stopper 123 is in contact with the guide member 113a.

Therefore, the sheet S, which has been subjected to the fixing process and is conveyed by the conveying roller pair 115, is guided by the guide member 112a and the guide surface 118a, and is driven by the discharge roller pair
The sheet is then discharged face-up onto the sheet discharge tray 124 by the discharge roller pair 116.

FIGS. 9 and 10 show the state of the flapper 118 and the sheet stopper 119 when the face-down discharge mode is selected.

At this time, the flapper 118 is
b is substantially parallel to the guide member 113a, and the first path 112 is closed and the second path 113 is opened. Further, the sheet stopper 119 is in a state of being pressed by the flapper 118 rotated in the counterclockwise direction and rotated in the counterclockwise direction.

Accordingly, the sheet S having been subjected to the fixing process and conveyed by the conveying roller pair 115 is, as shown in FIG.
It is guided by the guide member 113a and the guide surface 118b, guided to the second path 113, and moves downward.
At this time, the flapper 1
The sheet stopper 119 in contact with the sheet S
The seat S rotates counterclockwise due to its own waist and allows the sheet S to pass.

The sheet S moving downward in the second path 113 is sent to the third path 114 by the pair of reversing rollers 117 that are rotating forward. And the sheet S
When the rear end of the sheet passes through the sheet stopper 119, the pair of reversing rollers 117 rotates in the reverse direction. As a result, the second path 11
The sheet S guided to No. 3 moves upward with the rear end side at the top, as shown in FIG.

Then, as shown in FIG. 10, the sheet S moving upward on the second path 113 is
and enters the downstream portion of the first path 112 guided by the guide surface 118c. Then, the sheet is discharged face-down onto the sheet discharge tray 124 by the discharge roller pair 116.

When the sheet S moves upward in the second path 113, the sheet stopper 119 is
Since the sheet S is in contact with the flapper 118 with the urging force of 2 and closes the passage formed by the guide member 113a and the guide surface 118b, the sheet S does not move upstream of the first path 112.

The sheet S moving upward in the second path 113 is provided on the guide surface 119a of the sheet stopper 119.
Guide member 113b and guide surface 118c
, But at this time, the sheet S is placed on the guide surface 119a.
Is a force for rotating the sheet stopper 119 clockwise, so that the sheet stopper 119 does not separate from the flapper 118.

[0029]

However, the conventional sheet conveying apparatus 100A has the following problems.

That is, the sheet stopper 119 is in the state shown in FIG. 8 by the urging force of the coil spring 122 in the face-up discharge mode. In the face-down discharge mode, the flapper 118 is turned by the counterclockwise direction and is turned in the counterclockwise direction as shown in FIGS. 9 and 10.

In the state shown in FIGS. 9 and 10, the sheet stopper 119 is in contact with the flapper 118 by the biasing force of the coil spring 122, and closes the passage formed by the guide member 113a and the guide surface 118b. As a result, the sheet stopper 119 prevents the sheet S moving upward on the second path 113 from entering between the guide member 113a and the guide surface 118b.

The function of preventing the sheet S moving upward in the second path 113 from entering between the guide member 113a and the guide surface 118b is such that the sheet stopper 119 abuts against the flapper 119 with a slight pressure. However, if the sheet stopper 119 is brought into contact with the flapper 119 by using the biasing force of the coil spring 122, an excessive biasing force acts due to the characteristics of the coil spring 122. Sometimes. The biasing force of the coil spring 122 becomes a large load on a driving unit for driving the flapper 119, and causes a malfunction of the flapper 119.

Although this problem can be solved by using a large-capacity driving means, it is not practically preferable because it has problems such as an increase in the cost and size of the apparatus.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a sheet conveying apparatus which can drive a conveying direction changing unit with a small capacity driving unit without malfunction. .

[0035]

According to the present invention, a first path for guiding a sheet in a first direction and a branch from the first path for achieving the above object are provided. A second guide that guides the sheet moving along the path in the first direction in a second direction and a third direction toward the downstream portion of the first path in a direction opposite to the second direction. And a first conveyance direction setting posture which is disposed at a branch of the second path and moves the sheet in the first direction in the first path; and A second conveyance direction setting posture for moving the sheet in the second direction in the path, and a third conveyance direction setting posture for moving the sheet in the third direction in the second path. And the transport direction changing means can be selected in the third transport direction setting state. When, according to in which the sheet conveying apparatus comprising a, a sheet intrusion prevention means for preventing the entry of the sheet to close the passage leading to the upstream portion of the first path.

In order to achieve the above object, according to the present invention, when the conveyance direction changing means is in the third conveyance direction setting state, the sheet intrusion prevention means is urged by its own weight portion to allow the sheet to enter. Characterized in that it is positioned at a position for preventing the intrusion of the air.

[0037]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIGS. 1 to 3 show a first embodiment of the present invention.
1 shows a configuration of a main part of a sheet conveying apparatus according to an embodiment.

In describing the structure of the sheet conveying apparatus 100B, the same members as those of the sheet conveying apparatus 100A are denoted by the same reference numerals, and those which are not structurally and functionally different will be described. Omitted.

In the above-described conventional sheet conveying apparatus 100A, the sheet stopper 119, which is rotatable about the support shaft 121, is rotated clockwise by using the coil spring 122. In the case of (1), the sheet stopper 119 rotatable around the support shaft 121 is rotated clockwise by the function of the weight portion 119b provided integrally with the sheet stopper 119. In this case, a clockwise urging force acts on the sheet stopper 119 by the weight portion 119b.

FIG. 1 shows the state of the flapper 118 and the sheet stopper 119 when the face-up discharge mode is selected.

At this time, the flapper 118 does not press the sheet stopper 119, and the sheet stopper 119 is in a state where the stopper 123 is in contact with the guide member 113a.

FIGS. 2 and 3 show the flapper 118 and the sheet stopper 1 when the face-down discharge mode is selected.
19 are shown.

At this time, the sheet stopper 119 is pressed by the flapper 118 rotated in the counterclockwise direction and is turned in the counterclockwise direction. The sheet stopper 119 is urged by the weight portion 119b and is always in contact with the flapper 118.

FIG. 2 shows that the sheet S is
And a state in which the second path 113 is being moved downward by being guided by the guide surface 118b. At this time, the sheet S itself moves by rotating the sheet stopper 119 counterclockwise by the conveying force and the waist.

FIG. 3 shows a state in which the sheet S is guided by the guide member 113b and the guide surface 118c and moves upward on the second path 113. At this time, the sheet S is guided by the guide surface 119a of the sheet stopper 119 and goes between the guide member 113b and the guide surface 118c. However, the force exerted on the guide surface 119a by the sheet S rotates the sheet stopper 119 clockwise. Since the force is a force that causes the sheet stopper 119 to separate from the flapper 118, it does not occur.

In the state of FIG. 3, the sheet stopper 11
9 is in contact with the flapper 118 because the weight portion 11
Although this is due to the urging force of 9b, the contact pressure can sufficiently fulfill the sheet intrusion prevention function with a slight pressure.

In the case of the sheet conveying apparatus 100B, the sheet stopper 119 is in contact with the flapper 118 with a slight pressure by the urging force of the weight portion 119b. This contact pressure does not impose a large load on the driving means for driving the flapper 118. Therefore, it is not necessary to use a large-capacity driving means for driving the flapper 118. <Second Embodiment> FIGS. 4 to 6 show a second embodiment of the present invention.
1 shows a configuration of a main part of a sheet conveying apparatus according to an embodiment.

In describing the structure of the sheet conveying device 100C, the sheet conveying device 100A,
The same members as those of 100B are denoted by the same reference numerals, and a description of those members which do not change in structure and function are omitted.

In the case of the sheet conveying apparatuses 100A and 100B, a sheet stopper (119) that rotates around a support shaft (121) disposed outside the path is used. In such a case, a sheet stopper that rotates around a spindle disposed in the path is used.

The sheet stopper 130 of the sheet conveying apparatus 100C is mounted on a support shaft 120 of the flapper 118, and is rotatable around the support shaft 120. In this case, the sheet stopper 130 is attached to the support shaft 120 so as to be freely rotatable (freely fitted) so that it does not interlock with the rotation of the flapper 118.

The sheet stopper 130 is provided with a weight portion 13 provided integrally with the sheet stopper 130.
It rotates counterclockwise by the action of 0a.

FIG. 4 shows the state of the flapper 118 and the sheet stopper 130 when the face-up discharge mode is selected.

At this time, the tip 13 of the sheet stopper 130
Ob is in contact with a stopper 131 provided outside the guide member 113a.

FIGS. 5 and 6 show the flapper 118 and the sheet stopper 1 when the face-down discharge mode is selected.
30 postures are shown.

FIG. 5 shows that the sheet S is
And a state in which the second path 113 is being moved downward by being guided by the guide surface 118b. At this time, the sheet S itself moves by rotating the sheet stopper 130 clockwise by the conveying force and the waist.

FIG. 6 shows that the sheet S is
And a state in which the second path 113 is being moved upward by being guided by the guide surface 118c. At this time, the leading end 130 b of the sheet stopper 130 is in contact with the stopper 131, and shuts off the passage leading to the upstream portion of the first path 112.

In the case of the sheet conveying apparatus 100C, the sheet stopper 130 does not affect the operation of the flapper 118 at all. That is, it does not become a load on the driving means for driving the flapper 118. Therefore, it is not necessary to use a large-capacity driving means for driving the flapper 118.

In this specification, a case has been described in which the present invention is applied to a sheet conveying apparatus capable of discharging a sheet in both the face-up discharge mode and the face-down discharge mode. The present invention can be applied to any apparatus having two elements, that is, a conveyance direction changing unit that changes a sheet conveyance direction and a sheet intrusion prevention unit that prevents a sheet from entering a predetermined path. Needless to say.

[0059]

As described above, according to the present invention,
The sheet intrusion prevention means (sheet stopper) is biased by its own weight portion and is positioned at a position where sheet intrusion is prevented. Therefore, the sheet intrusion prevention means (sheet stopper) is biased by a coil spring and positioned at a position where sheet intrusion is prevented. In this case, the sheet intrusion preventing means does not impose a large load on the driving means for driving the conveying direction changing means.

Therefore, the transfer direction changing means can be driven by the small capacity driving means without malfunction.

Further, it is not necessary to attach a means (such as a coil spring) for urging the sheet intrusion prevention means.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a main part of a sheet conveying apparatus according to a first embodiment of the present invention and an operation in a face-up discharge mode.

FIG. 2 is a cross-sectional view illustrating an operation of the sheet conveying apparatus in FIG. 1 in a face-down discharge mode.

FIG. 3 is a cross-sectional view illustrating an operation of the sheet conveying apparatus in FIG. 1 in a face-down discharge mode.

FIG. 4 is a cross-sectional view illustrating a configuration of a main part of a sheet conveying apparatus according to a second embodiment of the present invention and an operation in a face-up discharge mode.

FIG. 5 is a cross-sectional view illustrating an operation of the sheet conveying apparatus in FIG. 4 in a face-down discharge mode.

FIG. 6 is a cross-sectional view illustrating an operation of the sheet conveying apparatus in FIG. 4 in a face-down discharge mode.

FIG. 7 is a cross-sectional view illustrating an overall schematic configuration of a laser beam printer (sheet processing apparatus) including a conventional sheet conveying apparatus.

FIG. 8 is a cross-sectional view illustrating a configuration of a main part of a conventional sheet conveying apparatus and an operation in a face-up discharge mode.

FIG. 9 is a cross-sectional view illustrating an operation of the sheet conveying apparatus in FIG. 8 in a face-down discharge mode.

FIG. 10 is a cross-sectional view illustrating an operation of the sheet conveying apparatus in FIG. 8 in a face-down discharge mode.

[Explanation of symbols]

100B, 100C Sheet conveying device 112 First path 113 Second path 118 Flapper (conveying direction changing unit) 119, 130 Sheet stopper (sheet intrusion preventing unit) 119b, 130a Weight unit 120 Flapper support shaft 131 Stopper (rotation control) Part) P1 first direction P2 second direction P3 third direction S sheet

Claims (5)

[Claims] A first path that guides a sheet in a first direction; and a sheet that branches off from the first path and is moving along the first path in the first direction. A second path leading in a third direction toward a downstream portion of the first path in a second direction and in a direction opposite to the second direction; and a second path that is disposed at a branch of the second path. A first conveyance direction setting state in which the sheet moves in the first direction in the first path; and a second state in which the sheet moves in the second direction in the second path. Transport direction setting means for selecting a second transport direction setting attitude, and a third transport direction setting attitude for causing a sheet to move in the third direction along the second path; and the transport direction changing means. Is in the third conveyance direction setting state, the passage leading to the upstream portion of the first path is closed to close the passage. A sheet intrusion prevention means for preventing intrusion of a sheet, wherein the sheet intrusion prevention means has a weight when the conveyance direction changing means is in the third conveyance direction setting state. The sheet conveying device is characterized in that the sheet conveying device is positioned at a position where the sheet is urged by a portion to prevent the sheet from entering. 2. The apparatus according to claim 1, wherein said transport direction changing means is rotated about a support shaft to be in one of the first, second, and third transport direction setting postures. The sheet conveying device as described in the above. 3. The sheet intrusion prevention means is rotatable about a spindle disposed outside the second path, and is biased by the weight portion in a predetermined direction about the spindle. The sheet conveying device according to claim 1, wherein the sheet conveying device is rotated to contact the conveying direction changing unit. 4. The sheet intrusion prevention means is rotatably mounted on a support shaft of the conveyance direction changing means, and rotates in a predetermined direction about the support shaft by the urging force of the weight portion. The sheet conveying device according to claim 1, wherein the sheet conveying device is in contact with a rotation restricting portion provided outside the second path. 5. A sheet processing apparatus according to claim 1, wherein said sheet processing apparatus performs predetermined processing on sheets fed one by one as a means for conveying sheets in a plurality of directions. A sheet processing apparatus comprising: a sheet processing apparatus.