JP2000335790A - Sheet transport device - Google Patents

Abstract

(57) [Problem] To provide a sheet conveying apparatus capable of preventing a decrease in conveying performance. SOLUTION: A first conveying roller pair 3 for conveying a sheet S is provided.
A second transport roller pair 5 that transports the sheet S from the first transport roller pair 3 in a direction different from that of the first transport roller pair 3,
A sheet conveying device provided with a guide means for guiding the sheet fed from the first conveying roller pair to the second conveying roller pair;
2 that locks the leading end of the sheet S fed from
1a, the guide member 21 having
The first position in which the leading end of the sheet S is locked by the locking portion 21a and the first position in which the leading end of the sheet S is rotated around the rotation shaft 17 and located in the vicinity of the second conveying roller pair 5. When the guide member 21 is located at the second position, the locked state between the leading end of the sheet S and the locking portion 21a is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device of an image forming apparatus such as a facsimile, a printer, and a copying machine (printing machine).

[0002]

2. Description of the Related Art In general, a sheet conveying apparatus having a curved conveying path is provided between a first conveying roller pair (first conveying means) for conveying a sheet and a second conveying roller pair (second conveying means). It has a curved guide plate. The sheet fed from the first conveying roller pair is guided by the guide plate and conveyed to the second conveying roller pair.
It is transported to the next site.

[0003]

However, according to the above-described technique, as the curvature of the curved portion of the guide plate becomes smaller, the friction between the leading end of the sheet and the guide plate becomes larger, and the leading end of the sheet is bent. There is. Further, there is a case where dust generated by sliding between the sheet and the guide plate adheres to the first and second conveying roller pairs and the like, thereby lowering the conveying force. Further, an increase in friction with the guide plate and a decrease in the conveying force may cause skew of the sheet. Therefore, the conventional sheet conveying device has a problem that the conveying performance of the sheet conveying device is not stable when there is a curved portion having a small curvature.

Accordingly, an object of the present invention is to provide a sheet conveying apparatus capable of stabilizing the conveying performance.

[0005]

According to a first aspect of the present invention, there is provided a first conveying means for conveying a sheet, and a second conveying means for conveying a sheet from the first conveying means in a direction different from the first conveying means.
A sheet conveying device comprising a conveying unit and a guide unit for guiding a sheet fed from the first conveying unit to a second conveying unit, wherein the guiding unit is related to a leading end of the sheet fed from the first conveying unit. A guide member having a locking portion for stopping, wherein the guide member is rotated at a first position where the leading end portion of the sheet is locked to the locking portion, and the second leading end is rotated about a rotation axis. A second position located in the vicinity of the means; and a locking state between the sheet leading end and the locking portion is released when the guide member is positioned in the second position. I do.

According to the first aspect of the present invention, the leading end of the sheet fed from the first conveying means is locked (collides) with the locking portion of the guide member. When the first conveying means further conveys the sheet excessively in a state where the leading end of the sheet is locked by the locking portion, the guide member is pushed by the sheet and pivots toward the second position. And the guide member is located at the second position.

When the guide member is located at the second position, the locking state between the leading end of the sheet and the locking portion is released by the pressing force of the sheet. Then, the leading end of the sheet is conveyed to the next part by the second conveying means, and the guide member returns to the first position by its own weight.

The sheet is guided by the second conveying means in a state where the sheet is locked by the locking portion of the guide member, so that friction between the sheet and the guide member hardly occurs. Can be prevented. Further, since dust on the sheet due to friction is unlikely to be generated, it is possible to prevent the dust from adhering to the first and second transport units and to prevent a reduction in the transport force of the sheet transport device. Further, skew of the sheet due to friction between the sheet and the guide member and reduction in the conveying force can be prevented. Therefore, it is possible to stabilize the transport performance of the sheet transport device.

According to a second aspect of the present invention, in the first aspect of the present invention, the guide means includes a stopper member for restricting rotation of the guide member, and when the guide member is located at the second position. And the guide member is in contact with the stopper member.

[0010] According to the second aspect of the present invention, the first aspect is provided.
In addition to providing the same operation and effect as the invention described in the above, the provision of the stopper member can prevent the guide member from excessively rotating, and the conveying force of the guide member at the second position can be reduced. Therefore, the locked state between the sheet leading end portion and the locking portion is easily released.

[0011] The invention described in claim 3 is the invention according to claim 1 or 2.
In the invention described in (1), the guide means includes a return member that urges the guide member in a direction to return to the first position.

According to the third aspect of the present invention, the first aspect is provided.
In addition to the effects similar to those of the invention described in Item 2, the guide member can be reliably returned from the second position to the first position by providing the return member.

The invention described in claim 4 is the first to third aspects of the present invention.
In the invention described in any one of (1) to (4), the guide member includes a bending portion that guides a sheet to bend.

According to the fourth aspect of the present invention, the first aspect is provided.
In addition to the same operation and effect as the invention described in any one of (3) to (3), the seat is rotated by the rotation of the guide member.
The sheet is guided and curved by the second transporting means, but the sheet is guided and received by the receiving portion of the guide member. Therefore, before the guide member is positioned at the second position, the sheet front end portion is bent by the sheet. The locking state between the locking member and the locking portion of the guide member is prevented from being released.

[0015] The invention according to claim 5 provides the invention according to claims 1 to 4.
The invention according to any one of the above, further comprising intermittent means for intermittently driving the second transport means, wherein the intermittent means makes the second transport means contact the sheet leading end portion with the second transport means. It is characterized by being driven.

According to the fifth aspect of the present invention, there is provided the first aspect.
In addition to the same operation and effect as the invention described in any one of (4) to (4), the leading end of the sheet guided by the second transport means by the guide member abuts on the second transport means. When the leading end of the sheet comes into contact with the second conveying means, the guide member returns to the first position, and a space necessary for the sheet to form slack is formed. On the other hand, the driving of the second transport means is stopped by the intermittent means. In this state, the sheet is further conveyed excessively by the first conveying means, so that the sheet forms slack in the space. Due to the strength of the sagging sheet, the leading end of the sheet becomes substantially linear, thereby correcting the oblique feeding (skew) of the sheet, so that the oblique feeding of the sheet can be prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment will be described in detail with reference to the accompanying drawings. 1 and 2
FIG. 4 is a diagram illustrating an operation of the sheet conveying device according to the first embodiment.

As shown in FIG. 1, the sheet conveying device 1 comprises:
For example, it is used in an image forming apparatus such as a facsimile, a printer, a copying machine, and the like. The first conveying roller pair (first conveying means) 3 for conveying the sheet S and the sheet S from the first conveying roller pair 3 Transport roller pair 5 for transporting to the site
And a guide means 7 for guiding the sheet S fed from the first transport roller pair 3 to a second transport roller pair (second transport means) 5.

The first transport roller pair 3 includes roller units 9 and 11
, The sheet S is conveyed by being rotated by driving from a drive source (not shown). Similarly, the second conveying roller pair 5 also holds the sheet S by the rollers 13 and 15 and conveys the sheet S to the next part by rotation.

The first and second transport roller pairs 3, 5
Have different conveying directions, and the sheet S fed from the first conveying roller pair 3 is connected to a guide member 2 described later.
With the guidance of No. 1, it turns approximately 90 degrees and is held between the rollers 5a of the second transport roller pair 5. That is, in the present embodiment, the transport path from the first transport roller pair 3 to the second transport roller pair 5 is curved at approximately 90 degrees.

The guide means 7 has a guide member 21 that rotates around the rotation shaft 17, a stopper member 23 that contacts the arm 19 of the guide member 21, and a return member 25. The guide member 21 is formed with a protrusion (locking portion) 21a, and the leading end of the sheet S fed from the first transport roller pair 3 is locked to the protrusion 21a.

The guide member 21 has a first position where the leading end of the sheet S shown in FIG.
The leading end of the sheet S shown in FIG. 1B is rotatable to a second position where the sheet S is located in the vicinity of the space 5 a between the rollers of the second conveying roller pair 5.

As shown in FIG. 1B, the stopper member 23 comes into contact with the arm 19 when the guide member 21 rotates to the second position, as shown in FIG.
1 is restricted. By providing the stopper member 23, excessive rotation of the guide member 21 can be prevented, and the guide member 21 can be prevented from colliding with the second transport roller pair 5. Further, since the conveying force is the pressing force of the sheet S when the guide member 21 is at the second position, the locked state between the leading end of the sheet S and the projection 21a is easily released.

The return member 25 is, for example, a spring or the like, and urges the guide member 21 in the direction of returning to the first position. The urging force causes the guide member 21 to move from the second position to the second position. Rotate (return) to position 1
It has become. By providing the return member 25,
The guide member 21 can be reliably returned from the first position to the second position.

Next, the operation of the first embodiment will be described based on the above configuration. The leading end of the sheet S fed from the first transport roller pair 3 is locked (collides with) with the locking portion 21a of the guide member 21, as shown in FIG. When the first conveying roller pair 3 further conveys the sheet S excessively in a state where the leading end of the sheet S is locked by the locking portion 21a, as shown in FIG. Reference numeral 21 is pushed by the sheet S, rotates toward the second position, abuts against the stopper member 23, and is located at the second position.

When the guide member 21 is located at the second position, the locking state between the leading end of the sheet S and the locking portion 21a is released by the pressing force of the sheet S as shown in FIG. You. Then, as shown in FIG.
Is conveyed to the next portion while being held between the rollers 5a of the second conveying roller pair 5, and the guide member 21 returns to the first position by the urging force of the return member 25.

The sheet S is fixed to the locking portion 21 of the guide member 21.
When the sheet S and the guide member 21 are guided by the second conveying roller pair 5 in a state where the sheet S and the guide member 21 are locked, the leading end of the sheet S can be prevented from being bent. . Further, since the dust of the sheet S is hardly generated due to friction, the dust is generated by the first and second conveying roller pairs 3 and 5.
Can be prevented, and a reduction in the conveying force of the sheet conveying apparatus 1 can be prevented.
Further, skew of the sheet S due to friction between the sheet S and the guide member 21 and a reduction in the conveying force can be prevented. Therefore, the conveyance performance of the sheet conveyance device 1 can be stabilized.

Next, another embodiment will be described. In the description, the same parts as those described above are denoted by the same reference numerals and the description thereof will be omitted.

FIGS. 3 and 4 are diagrams illustrating the operation of the sheet conveying apparatus according to the second embodiment. As shown in FIGS. 3 and 4, in the second embodiment, the sheet S fed from the first conveying roller pair 3 is turned by approximately 180 degrees by the guide of the guide member 21 to turn the second conveying roller pair 3. 5
It is different from the above-described embodiment in that it is held between the rollers 5a. The symbol R in FIGS. 3B and 4C is a loop forming space for forming a slack (loop) of the sheet S, and is shown in FIGS. 2A and 4D. ), The loop forming space R is omitted.

In the sheet conveying apparatus 1 according to the second embodiment,
As in the above-described embodiment, in FIG.
The guide member 21 is in contact with the stopper portion 23 and is located at the second position in FIG. 3B. Then, in FIG. 4C, the pressing force of the sheet is generated by the R portion, and the locked state between the sheet S and the locking portion 21a is released, and in FIG. The guide member 21 is returned to the first position while being transported by the transport roller pair 5.

Even when the sheet S is turned by approximately 180 degrees and conveyed as in the second embodiment, friction between the sheet S and the guide member 21 hardly occurs.
It is possible to prevent the conveyance performance of the sheet conveyance device 1 from deteriorating.

FIGS. 5 and 6 are views for explaining the operation of the sheet conveying apparatus according to the third embodiment. As shown in FIGS. 5 and 6, in the third embodiment, the sheet S is conveyed by being turned approximately 180 degrees, and the rotating shaft 17 is in contact with the roller shaft of the roller unit 11 of the first conveying roller pair 3. This embodiment is different from the above-described embodiment in that the guide member 21 is coaxial and a curved portion 21b is formed in the guide member 21.

The curved portion 21b of the guide member 21 is curved in the circumferential direction drawn by the guide member 21 around the rotation shaft 17, and as shown in FIG. Is positioned to guide and receive (enclose) the curvature of the sheet S.

In FIG. 5A, the sheet S is the guide member 2
The guide member 21 is located at the second position as shown in FIG. 5 (b). At this time, the sheet S
The sheet S is curved in the circumferential direction drawn by the guide member 21, and the curved portion 21 b receives the curve of the sheet S. Therefore, before the guide member 21 is located at the second position, it is possible to prevent the locking state between the leading end of the sheet S and the locking portion 21a of the guide member 21 from being released by the stiffness due to the bending of the sheet S. ing.

When the guide member 21 comes into contact with the stopper member 23 and is located at the second position, as shown in FIG. 6C, the locked state between the sheet S and the locking portion 21a is released. As shown in FIG. 6D, the sheet S is conveyed to the next portion by the second conveying roller pair 5.

FIGS. 7 to 9 are views for explaining the operation of the sheet conveying apparatus according to the fourth embodiment. As shown in FIGS. 7 to 9, the fourth embodiment is different from the above-described embodiment in that an intermittent means 27 for intermittently driving the second conveying roller pair 5 is provided.

The intermittent means 27 is, for example, an electromagnetic clutch or the like, and makes the second transport roller pair 5 rotate.
It stops the rotation drive. The intermittent means rotates the second transport roller pair 5 after the leading end of the sheet S abuts on the roller gap 5a of the second transport roller pair 5.

In FIG. 7A, the leading end of the sheet S comes into contact with the locking portion 21a of the guide member, and in FIG. 7B, the guide member 21 is located at the second position. Then, in FIG. 8C, the locked state between the leading end of the sheet S and the locking portion 21a is released, and in FIG. 8D, the leading end of the sheet S contacts the gap 5a between the rollers.

At this time, since the guide member 21 has returned to the first position, the space K for the sheet S to be slackened.
Is formed. On the other hand, the rotation of the second conveying roller pair 5 is stopped by the intermittent means 27, and as shown in FIG.
Is transported further excessively to form a slack in the space K. Due to the strength of the sagging sheet S, the leading end of the sheet S is aligned substantially linearly, whereby the sheet S is corrected for oblique feeding (skew). Therefore, the oblique feeding of the sheet S can be prevented.

After the leading end of the sheet S is straightened,
The intermittent means 27 drives the second transport roller pair 5 to rotate, and the second transport roller pair 5 transports the sheet S to the next portion while holding the sheet S between the rollers 5a.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, the intermittent means 27 of the fourth embodiment
May be provided in the sheet conveying apparatuses 1 of the first to third embodiments. Further, the guide member 21 may rotate (return) to the first position by its own weight without providing the return member 25.

[0042]

According to the first aspect of the present invention, the sheet is
Since the sheet is guided by the second conveying means in a state where the sheet is locked to the locking portion of the guide member, friction between the sheet and the guide member is unlikely to occur, so that it is possible to prevent the sheet tip from being bent. Further, since dust on the sheet due to friction is unlikely to be generated, it is possible to prevent the dust from adhering to the first and second transport units and to prevent a reduction in the transport force of the sheet transport device. Further, skew of the sheet due to friction between the sheet and the guide member and reduction in the conveying force can be prevented. Therefore, it is possible to stabilize the transport performance of the sheet transport device.

According to the second aspect of the invention, the same effects as those of the first aspect of the invention can be obtained, and by providing the stopper member, excessive rotation of the guide member can be prevented, and the guide member can be prevented from rotating excessively. When the member is in the second position, the conveying force becomes the pressing force of the sheet, so that the locked state between the leading end of the sheet and the locking portion is easily released.

According to the third aspect of the present invention, the same effect as that of the first or second aspect of the present invention is obtained, and the provision of the return member ensures that the guide member is moved from the second position to the first position. Can be restored.

According to the fourth aspect of the present invention, the same effect as that of the first aspect of the present invention is provided, and the curved portion of the guide member receives the slack of the sheet, so that the guide member can be provided. Before is located in the second position,
The locking state between the leading end of the sheet and the locking portion of the guide member due to the slack of the sheet is prevented from being released.

According to the fifth aspect of the present invention, the same effect as that of the first aspect of the present invention can be obtained, and the leading end of the sheet abuts between the rollers of the second conveying roller pair. Due to the strength of the stiffness due to the sometimes formed sheet slack, the leading end of the sheet is aligned substantially linearly, thereby correcting the skew feeding (skew) of the sheet, thereby preventing the skew feeding of the sheet. it can.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating an operation of a sheet conveying apparatus according to a first embodiment, and FIG. 1A is a diagram illustrating a state in which a leading end of a sheet is locked by a locking portion of a guide member; (B) is a figure which shows the state in which the guide member is located in the 2nd position.

FIGS. 2A and 2B are diagrams for explaining the operation of the sheet conveying apparatus of FIG. 1, and FIG. 2C is a diagram illustrating a state in which a locked state between a leading end portion of the sheet and a locking portion is released; () Is a diagram illustrating a state in which the sheet is being conveyed by the second conveying roller pair.

FIGS. 3A and 3B are diagrams illustrating an operation of the sheet conveying apparatus according to the second embodiment, and FIG. 3A is a diagram illustrating a state in which a leading end of a sheet is locked by a locking portion of a guide member; (B) is a figure which shows the state in which the guide member is located in the 2nd position.

4A and 4B are diagrams illustrating an operation of the sheet conveying device in FIG. 3; FIG. 4C is a diagram illustrating a state in which a locked state between a leading end portion of a sheet and a locking unit is released; () Is a diagram illustrating a state in which the sheet is being conveyed by the second conveying roller pair.

FIGS. 5A and 5B are diagrams illustrating an operation of the sheet conveying apparatus according to the third embodiment, and FIG. 5A is a diagram illustrating a state in which a leading end of a sheet is locked by a locking portion of a guide member; (B) is a figure which shows the state in which the guide member is located in the 2nd position.

6A and 6B are diagrams illustrating the operation of the sheet conveying device in FIG. 5; FIG. 6C is a diagram illustrating a state in which the locked state between the leading end portion of the sheet and the locking portion is released; () Is a diagram illustrating a state in which the sheet is being conveyed by the second conveying roller pair.

FIGS. 7A and 7B are diagrams illustrating an operation of the sheet conveying apparatus according to the fourth embodiment, and FIG. 7A is a diagram illustrating a state in which a leading end of a sheet is locked by a locking portion of a guide member; (B) is a figure which shows the state in which the guide member is located in the 2nd position.

8A and 8B are diagrams illustrating the operation of the sheet conveying device in FIG. 7; FIG. 8C is a diagram illustrating a state in which the locked state between the leading end portion of the sheet and the locking unit is released; () Is a diagram showing a state in which the leading end of the sheet is in contact between the rollers of the second pair of conveying rollers.

9 is a diagram illustrating a state in which a slack is formed in the sheet in the operation of the sheet conveying device in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet conveyance device 3 1st conveyance roller pair (1st conveyance means) 5 2nd conveyance roller pair (2nd conveyance means) 7 Guide means 17 Rotating shaft 21 Guide member 21a Projection part (locking part) 21b Curved part 23 Stopper member 25 Return member 27 Intermittent means

Claims (5)

[Claims] A first conveyance unit configured to convey a sheet;
A sheet transport device comprising: a second transport unit that transports a sheet from a transport unit in a direction different from that of the first transport unit; and a guide unit that guides the sheet fed from the first transport unit to the second transport unit. The guide means includes a guide member having a locking portion for locking the leading end of the sheet fed from the first conveying means, and the guide member has a first position at which the leading end of the sheet is locked to the locking portion. The sheet leading end is rotatable about a rotation axis to a second position located near the second conveying means, and when the guide member is located at the second position, the sheet leading end is rotated. A sheet conveying device in which a locked state between the section and the locking section is released. 2. The apparatus according to claim 1, wherein said guide means includes a stopper member for restricting rotation of said guide member, and said guide member comes into contact with said stopper member when said guide member is located at said second position. 2. The sheet conveying device according to 1. 3. The sheet conveying apparatus according to claim 1, wherein the guide unit includes a return member that urges the guide member in a direction to return to the first position. 4. The sheet conveying apparatus according to claim 1, wherein the guide member includes a curved portion that guides the sheet to bend due to the rotation of the guide member. 5. An intermittent means for intermittently driving the second transport means, wherein the intermittent means drives the second transport means after the leading end of the sheet is brought into contact with the second transport means. The sheet conveying device according to claim 1, wherein