JP2002362785A - Sheet delivering device and image forming device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet delivering device and an image forming device with the same, capable of positioning a sheet with a simple structure without enlarging the device. SOLUTION: A fixed end reference guide 23 is mounted on one end part orthogonal to the sheet delivering direction of a delivery passage 21, a movable end reference guide 24 capable of coming in and out to the delivery passage 21, is mounted on a center side of the delivery passage 21 with respect to the fixed end reference guide 23, and the movable end reference guide 24 is selectively moved between a first position for positioning the width direction of the sheet S and a second position not positioning the sheet S, when the sheet S is passed therethrough. The sheet S passed through the delivery passage 21 is skewed, and delivered while pressed to the fixed end reference guide 23, or the movable end reference guide 24 moved to the first position in passing the sheet S, to perform the positioning of the sheet S.

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 and an image forming apparatus having the same, and more particularly, to a sheet conveying apparatus in which an obliquely fed sheet is conveyed while being pressed against an end reference guide provided in a conveying path. About what to do.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, for example, a sheet passing through a conveyance path is skewed, and an end reference guide provided at one end of the conveyance path orthogonal to the sheet conveyance direction. There is a device provided with a sheet transporting device that performs sheet positioning while performing pressing to align the sheets. When such a sheet conveying device is used, since the sheet is conveyed along the end reference guide, the position of one side end of the sheet is determined, and as a result, the image is positioned at the normal position. Will be transferred to

However, when the sheet is aligned in the width direction by such a method, when the position of the sheet in the width direction is adjusted for a narrow sheet, the sheet is shifted to one side of the conveyance path. Will be able to

When the sheet is moved to one side of the conveyance path in this way, after the image is transferred, when the sheet passes through the fixing device, the sheet does not pass through the center of the fixing device, and the toner cartridge is used. Does not pass through the center of the toner cartridge. For this reason, when passing through the fixing device, the temperature of only one side of the sheet may increase,
In an image forming apparatus using a toner cartridge, bias of toner or the like is likely to occur.

[0005] In view of this, the end reference guide is disposed so as to be movable in a direction perpendicular to the sheet conveyance direction, and the sheet is conveyed so that the center in the width direction of the sheet is always at a constant reference position, a so-called center reference method. Has been proposed. The sheet is conveyed so that the center in the width direction of the sheet is always at a constant reference position regardless of the sheet size, so that the sheet is sent to the left and right positions of the fixing device, so that the temperature rise on only one side is prevented. And the toner is less likely to be biased.

FIG. 7 is a perspective view showing the structure of such a conventional sheet conveying apparatus. In FIG. 7, reference numeral 102 denotes an end movable in a sheet width direction which is a direction orthogonal to the sheet conveying direction. It is a reference guide. An actuator 101 is attached to the end reference guide 102, and the actuator 101 moves the end reference guide 102 in the sheet width direction.

Reference numeral 103 denotes a pair of skew feeding rollers provided in the vicinity of the end reference guide of the conveying path 104, and the sheet S is moved by the pair of skew feeding rollers 103 to the end reference guide 1.
After the sheet S is skewed in the direction of 02 and the sheet S comes into contact with the end reference guide 102, the sheet S is conveyed along the end reference guide 102.

On the other hand, upstream of the end reference guide 102,
A sheet width detection unit 107 including a detection flag 105 and a photo sensor 106 is provided. The detection flag 105 is arranged at a position at a certain distance from the center of the conveyance path 104 in the sheet width direction so that the width of the sheet can be determined.

By disposing the sheet width detecting means 107 at such a position, when a sheet having a certain sheet width is conveyed, the normal photo sensor 106
The detection flag 105 located between the light-emitting element and the light-receiving element (not shown) comes into contact with the leading end of the sheet and falls down, whereby it is possible to detect the passage of a wide sheet.

Here, the sheet width detecting means 10
When the passage of a wide sheet is detected by 7, the end reference guide 102 is moved by the actuator 101 to a position such that the center of the sheet in the width direction matches, for example, the reference position of the center of the conveyance path 104 in the sheet width direction. .

The sheet that has passed the sheet width detecting means 107 is thereafter fed obliquely toward the end reference guide 102 by a pair of oblique feed rollers 103 arranged near the end reference guide. At this time, since the end reference guide 102 has moved to a position where the center in the width direction of the sheet matches the reference position, the end reference guide 102 is skewed toward the end reference guide 102 and pressed against the end reference guide 102. The center of the sheet in the width direction matches the reference position. As a result, the position of the sheet is determined, and the image is transferred to a regular position on the sheet by a transfer unit such as an image forming apparatus.

[0012]

However, such a sheet conveying apparatus and an image forming apparatus having the same require an actuator for moving the end reference guide 102 in the sheet width direction. Depending on the width of the corresponding sheet, for example, in the case of supporting an A4 sheet and an A5 sheet, the movable range of the end reference guide 102 is about 30 mm, and an actuator having a large displacement such as a motor is required. Becomes As a result, the size of the device is increased.

If the position of the end reference guide 102 shifts, the toner image transferred to the sheet S also shifts accordingly, and the end reference guide 102 needs to be accurately positioned. The configuration for controlling the position of the reference guide 102 is complicated.

Further, the end reference guide 102 detects the sheet width in advance, and it is necessary to move the end reference guide 102 to a position corresponding to the sheet width before the sheet is conveyed. A tip detecting means is required, and the structure becomes complicated.

It is to be noted that a method of moving the end reference guide by the user without using the actuator and the leading end detecting means is also conceivable. However, when such a method is employed, for example, the user is required to set a sheet. Operability becomes poor.

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and has a simple structure and a sheet conveying apparatus capable of performing sheet positioning without increasing the size of the apparatus. It is an object of the present invention to provide an image forming apparatus provided with:

[0017]

According to the present invention, a sheet passing through a conveying path is obliquely fed and conveyed while being pressed against an end reference guide provided at one end of the conveying path orthogonal to the sheet conveying direction. Thus, in the sheet conveying apparatus configured to perform sheet alignment, a fixed end reference guide provided at one end of the conveyance passage orthogonal to the sheet conveyance direction, and the conveyance passage being more than the fixed end reference guide. A movable end reference guide which is provided at a central portion of the sheet and is capable of moving in and out of the conveyance path. When the sheet passes through the movable end reference guide, alignment of the sheet in the width direction is performed. The sheet is selectively moved to a first position to be performed or a second position not to perform the position alignment of the sheet.

Further, according to the present invention, there is provided a turning member which is turned by being pressed by the sheet when a sheet of a predetermined size passes through the conveyance path, and wherein the moving member is interlocked with the turning operation of the lever member. The end reference guide is configured to be moved from the first position to the second position.

Further, the present invention is characterized in that a curved sheet conveying path is provided upstream of the conveying path.

According to the present invention, there is provided an image forming section, and a sheet which is conveyed to the image forming section and is fed obliquely to a sheet passing through a conveying path, and is provided at one end of the conveying path orthogonal to the sheet conveying direction. In the image forming apparatus having a sheet conveying device configured to perform sheet alignment by pressing while being pressed against the end reference guide,
The sheet transporting apparatus is any one of the above.

Further, as in the present invention, a fixed end reference guide is provided at one end of the conveyance passage orthogonal to the sheet conveyance direction, and the conveyance passage is located closer to the center of the conveyance passage than the fixed end reference guide. A movable end reference guide is provided which is freely retractable, and the movable end reference guide is provided at a first position where the sheet is aligned in the width direction or a second position where the sheet is not aligned when the sheet passes. Selectively move. Then, the sheet passing through the conveyance path is skewed and conveyed while being pressed against the fixed end reference guide or the moving end reference guide moved to the first position when the sheet passes, thereby aligning the sheet. To do.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a laser beam printer which is an example of an image forming apparatus provided with a sheet conveying device according to an embodiment of the present invention.

In FIG. 1, reference numeral 100 denotes a laser beam printer, which can form images on both sides of a sheet. The laser beam printer 100 includes a laser light source (not shown), a high-speed rotating scanner mirror 1a,
A laser scanner 1 having a folding mirror 1b, an image forming unit 2A for forming an image, a feeding unit 5A for separating and feeding the sheets S one by one, and forming an image on one side and then forming an image on the back side For example, a sheet re-feeding conveyance section 3A for feeding a sheet to the image forming section 2A again is provided.

Here, the image forming section 2A includes a process cartridge 2, a transfer roller 4, and the like, and a feeding unit 5A feeds a sheet cassette 5 on which sheets S are stacked and feeds the sheets S stored in the sheet cassette 5. Paper roller 6, sheet S
Is provided with a separation pad 7 and the like for separating the sheet one by one. The process cartridge 2 integrally includes the photosensitive drum 3 and process means (charging means, developing means, and cleaning means) acting on the photosensitive drum 3, and is detachable from a laser beam printer main body (hereinafter, referred to as an apparatus main body) 100A. It has become.

The re-feeding / conveying section 3A is a curved sheet conveying path which starts from the upper discharge roller pair 14 and reaches a junction 30 with the conveying path from the sheet feeding cassette 5 and the conveying path. The roller 21 is formed around the passage 21, and includes a lower discharge roller 13a and a reverse discharge roller 1 that comes into contact with the upper discharge roller pair 14, the post-fixing roller pair 13.
6, a sheet conveying device having a flapper 17, a horizontal registration correcting section 31, and the like.

Here, the lateral registration correcting section 31 is provided with a pair of skew feeding rollers 22 and an end reference guide 23 (24) for aligning the sheet S in the width direction, and an image is formed on one side. After that, the sheet S conveyed to form an image on the back side is pressed against the end reference guide 23 (24) by the pair of oblique feed rollers 22 so that the second side
It has a function of correcting the position in the width direction of the sheet S in preparation for the (back) image formation.

The lower discharge roller 13a sandwiches the sheet S, on which the toner image has been fixed, between the rollers 13b, conveys the sheet S to the upper discharge roller pair 14 stacked on the discharge unit 15, and When an image is formed on both sides of the sheet S, the sheet S switched back by the upper discharge roller pair 14 is conveyed to the horizontal registration correction unit 31 while being sandwiched between the reversing rollers 16 as described later. .

In FIG. 1, reference numeral 12 denotes a fixing unit which is a fixing unit for fixing the toner image by heating the toner image transferred to the sheet S by a heater 12b and further pressing the toner image by a pressing roller 12a. This is a controller board that controls the operation of the laser beam printer 1 and has a function of forming an image signal from a connected computer (not shown).

Reference numeral 8 denotes a transport roller for transporting the sheet S fed from the paper feed roller 6, reference numeral 9 denotes a registration roller for aligning the transported sheet, and reference numeral 10 denotes a transported sheet S.
Is a registration roller which is disposed to face the registration roller 9.

Next, an image forming operation of the laser beam printer 100 configured as described above will be described.

When image information is sent from a personal computer (not shown) or the like, and the controller board 18 that has performed image forming processing of the image information issues a print signal, the controller board 18 is loaded on the sheet cassette 5 detachably mounted on the apparatus main assembly 100A. The sheet S is fed one by one by a separation pad 7 and a sheet feeding roller 6, and sent to a nip between the photosensitive drum 3 and the transfer roller 4 in the process cartridge 2.

On the other hand, the laser scanner 1 irradiates a bit image of the image information (laser light) onto the photosensitive drum based on the image information together with the print command.
A latent image is formed on the surface of the photosensitive drum 3 according to the bit image. Further, by developing this latent image, a toner image is formed on the photosensitive drum.

Then, the toner image formed on the photosensitive drum in this manner is then transferred to the nip between the photosensitive drum 3 and the transfer roller 4 by the conveying roller 8 and the registration roller 9 in synchronization with the formation of the toner image. Sheet S sent
Then, the transfer is performed by applying a transfer voltage to the transfer roller 4. Further, the sheet S on which the toner image has been transferred
Is sent to the fixing unit 12 and heated and pressed by the fixing unit 12, whereby the toner image is fixed semi-permanently.

When the controller board 18 has received a signal for forming an image on only one side, the flapper 17 is at the position shown by the solid line. As a result, the sheet S that has passed through the fixing unit 12 is sent to the post-fixing roller pair 13, is sent to the upper discharging roller pair 14 via the flapper 17 and the discharging guide 19, and then is discharged by the upper discharging roller pair 14. It is discharged to the unit 15.

The sheet S is set on the basis of the center in a state where the sheet S is fed from the paper feed cassette 5, and an image is formed on the basis of the center when forming an image.

On the other hand, when the controller board 11 has received a signal for forming an image on both sides, the upper discharge roller pair 14 reversely rotates after the rear end of the sheet has passed through the front end of the flapper 17, and the flapper 17 has two points. Move to the position indicated by the chain line. As a result, the sheet S located at the position indicated by S1 in FIG. 1 is sent to the reversing path 20 by the post-fixing roller 13a and the reversing roller 16, and
Transported to

Here, the sheet conveyed to the conveying path 21 is conveyed by a pair of skew feeding rollers 22 and is further pressed by an end reference guide 23 (24) by receiving a conveying force in the sheet width direction. Division reference guide 23
It is transported along (24). Then, the sheet S is conveyed along the end reference guide 23 (24), so that the end of the sheet S follows the end reference guide 23 (24), and the position of the end of the sheet S is the regular position. Will be fitted to.

Thereafter, the sheet S is further conveyed by the skew feeding roller pair 22 to be conveyed to the conveying roller pair 8 and re-conveyed to the image forming section 2A. At this time, since the surface of the sheet S on which the toner image is not formed is in contact with the photosensitive drum 3, the toner image is transferred again by the image forming unit 2A and fixed to form an image on both surfaces. Will be

FIG. 2 is a perspective view showing the configuration of such a lateral registration correcting section 31. As shown in FIG. End reference guides 23 and 24 having contact surfaces 23a and 24a are provided. In addition, 26
Is a leaf spring which abuts the skew feeding roller 22a and presses the skew feeding roller 22a and the skew feeding roller 22b to form the skew feeding roller pair 22.

Here, in this embodiment, the end reference guide 23 provided at one end of the conveying passage 21 in the sheet width direction is fixed to the conveying passage 21, and is fixed to one end of the conveying passage 21. An end reference guide 24 provided closer to the center of the conveyance passage 21 than the end reference guide (hereinafter, referred to as a fixed end reference guide) 23 is provided to be able to protrude and retract from the conveyance passage 21.

On the other hand, in the same figure, reference numeral 25 denotes a rotating member for allowing the retractable end reference guide 24 (hereinafter referred to as a moving end reference guide) to protrude and retract from the transport path 21. The rotation member 25 is a horizontal registration correction unit 31
Are rotatably supported on a shaft 25b as a fulcrum.

The pivoting member 25 projects from the conveying path 21 and abuts on the sheet, and an end protrudes from the bottom of the movable end reference guide 24 at the end as shown in FIG. A laterally long locking hole 24 formed in the stopping portion 24d
e provided with a pin 25c to be locked to the arm 25d
have.

Here, when a sheet S of a predetermined size, in this embodiment, an A4 size sheet S is conveyed, the rotating member 25 is brought into contact with the contact portion 2 by the sheet S.
5a is provided at a position where it is pressed. Also,
The turning member 25 is urged in a counterclockwise direction about a shaft 25b as a fulcrum by an urging member (not shown).
From the outside.

By providing such a rotating member 25, for example, an A4 size sheet S is conveyed to the conveying path 21, and the sheet S is brought into contact with the contact portion 2 of the rotating member 25.
When the rotating member 25 is pressed, the rotating member 25 rotates counterclockwise around the shaft 25b, and the movable end reference guide 24 adjusts the position of the sheet S in the width direction by the rotation of the rotating member 25. From the first position where the sheet S is to be transferred, the sheet S is moved to a second position where the sheet S below the sheet conveyance surface of the conveyance path 21 does not contact, in other words, the sheet S is not aligned.

In the present embodiment, the movable end reference guide 24 has slide guide grooves 24b extending vertically in the upstream end and the downstream end in the sheet conveying direction, as shown in FIG. A stopper 24c is provided, and the slide guide groove 24b of the stopper 24c is engaged with a slide guide 23b provided on the bottom surface of the transport passage 21 shown in FIG. Has become.

The moving end reference guide 24 is always moved by the urging spring 27 as shown in FIG.
, And the position in the height direction is defined by the normal stopper 24c abutting against the lower surface of the transport passage 21.

Next, a description will be given of the operation of positioning the A4 size sheet S in the lateral registration correcting section 31 having the above-described configuration.

As described above, in order to form an image on both sides, an A4 size sheet S is fed into the transport path 21 via the reversing path 20, and the leading end of the sheet S is
When the contact portion 25a of the rotating member 25 is pressed as shown in FIG. 7, the rotating member 25 starts rotating clockwise around the shaft 25b.

When the rotating member 25 rotates clockwise in this manner, the movable end reference guide 24 is moved by the biasing spring 2.
While compressing the sheet 7, the sheet S descends from the first position where the sheet S is aligned in the width direction, and moves to the second position where the sheet S is not in contact with the sheet S, that is, the sheet is not aligned.

When the sheet S is fed into the transport path 21 as described above, the sheet S is curved following the curved shape of the reversing path 20, so that the rigidity of the sheet S is increased. For this reason, it is possible to pass while rotating the rotating member 25.

On the other hand, after the rotating member 25 is rotated, the sheet S eventually reaches the skew feeding roller pair 22, and is skewed toward the end reference guides 23 and 24 by the skew feeding roller pair 22. become. Here, when the sheet moves in the direction of the end reference guides 23 and 24, since the moving end reference guide 24 has already moved downward, as shown in FIG. Abutting surface 2 of guide 23
3a, and is then conveyed along the fixed end reference guide 22.

When the end of the sheet S is conveyed along the abutting surface 23a of the fixed end reference guide 23, the sheet S is positioned at a regular position and conveyed to the conveying roller 8. Is done.

Next, A4 in the horizontal registration correction unit 31
The alignment operation of a sheet S having a size smaller than the size, for example, A5 size, will be described.

In this case, when the A5 size sheet S is sent to the conveyance path 21 via the reversing path 20, the A5 size
The sheet S having a size is conveyed without the leading end contacting the contact portion 25 a of the rotating member 25 because the sheet width is narrow.

Therefore, the movable end reference guide 24 does not move downward. That is, at this time, the movable end reference guide 24 is urged upward by the urging spring 27, and the position in the height direction is fixed because the stopper 24c abuts against the bottom surface of the transport passage 21.

On the other hand, thereafter, the sheet S reaches the skew feeding roller pair 22 and is skewed toward the end reference guides 23 and 24 by the skew feeding roller pair 22. Here, when the sheet moves in the direction of the end reference guides 23 and 24, the moving end reference guide 24 is at the first position where the sheet comes into contact with the sheet. It is conveyed along the abutment surface 24 a on the unit reference guide 24.

When the end of the sheet S is conveyed along the abutting surface 24a of the movable end reference guide 24, the sheet S is positioned at a regular position and conveyed to the conveying roller 8. Is done.

As described above, the fixed-end reference guide 23 and the movable-end reference guide 24 are provided in the transport path 21, and the sheet S passing through the transport path 21 is obliquely fed. The sheet S is conveyed while being pressed against the fixed end reference guide 23 or the moving end reference guide 24 moved to the first position when the sheet is moved, so that the structure is simple and the apparatus becomes large. And sheet alignment can be performed reliably.

Further, by moving the movable end reference guide 24 by the sheet S via the rotating member 25 without using an actuator, the structure of the apparatus is simplified, and a more compact and low-cost sheet conveying apparatus is provided. Can be provided.

Further, since the rotating member 25 and the movable end reference guide 24 are linked, the sheet size can be detected without using a photo sensor or the like for the tip detecting means. In addition, by selectively moving the movable end reference guide 24 according to the size of the sheet, it is possible to form images on both sides of a sheet of a plurality of sizes without operating the apparatus by the user.

[0062]

As described above, according to the present invention, as in the present invention, the fixed end reference guide is provided in the transfer passage, and the movable end which is movable toward and away from the transfer passage at the center of the transfer passage with respect to the fixed end reference guide. In addition to providing the unit reference guides, the sheet passing through the conveyance path is skewed, and when the sheet passes through the fixed end reference guide or the sheet, the sheet is conveyed while being pressed against the moving end reference guide moved to the first position. The structure can be simple, and the sheet can be positioned without increasing the size of the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a laser beam printer as an example of an image forming apparatus provided with a sheet conveying device according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a configuration of a horizontal registration correction unit of the sheet conveying device.

FIG. 3 is a front cross-sectional view of a main part showing a configuration of the horizontal registration correction unit.

FIG. 4 is a perspective view illustrating an operation of aligning an A4 size sheet in the horizontal registration correction unit.

FIG. 5 is a side sectional view of an essential part for explaining an operation of aligning an A4 size sheet in the lateral registration correction unit.

FIG. 6 is a side sectional view of a main part for explaining an alignment operation of an A5 size sheet in the horizontal registration correction unit.

FIG. 7 is a perspective view illustrating a configuration of a conventional sheet conveying apparatus.

[Explanation of symbols]

 Reference Signs List 2A Image forming unit 3A Re-feeding / conveying unit 20 Reversing path 21 Conveying path 22 Oblique feed roller pair 23 Fixed end reference guide 24 Moving end reference guide 25 Rotating member 31 Lateral registration correction unit 100 Laser beam printer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihisa Ibaraki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takaaki Kawade 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-corporation F term (reference) 3F101 FB04 FC18 FE01 LA01 LB03 3F102 AA01 AB01 BA02 BA11 BB04 BB05 BB17 DA06 EA06 EC11 FA03

Claims (4)

[Claims] 1. A sheet passing through a conveyance path is skewed,
In a sheet transporting apparatus configured to perform sheet alignment by pressing the sheet while pressing against an end reference guide provided at one end of the transport path orthogonal to the sheet transport direction, the sheet transport direction of the transport path and A fixed end reference guide provided at one end orthogonal to the moving end reference guide, which is provided closer to the center of the transport path than the fixed end reference guide, and is movable with respect to the transport path; When the sheet passes through the moving end reference guide, the sheet is selectively moved to a first position where the sheet is aligned in the width direction or a second position where the sheet is not aligned. A sheet conveying device, characterized in that: And a rotating member that is pressed by the sheet and rotates when the sheet of a predetermined size passes through the conveyance path, wherein the moving end reference is interlocked with the rotating operation of the lever member. The sheet conveying device according to claim 1, wherein the guide is configured to move from the first position to the second position. 3. The sheet conveying apparatus according to claim 1, wherein a curved sheet conveying path is provided upstream of the conveying path. 4. An image forming section, and an end portion provided at one end of the conveying path, which conveys the sheet to the image forming section and obliquely feeds the sheet passing through the conveying path, and is orthogonal to a sheet conveying direction of the conveying path. 4. An image forming apparatus comprising: a sheet conveying device configured to perform sheet alignment while pressing the sheet while pressing against a reference guide, wherein the sheet conveying device includes the sheet conveying device according to claim 1. An image forming apparatus characterized in that: