JPH07101612A - Paper sheet conveying device - Google Patents

Abstract

PURPOSE:To positively correct curl of a paper sheet, reduce the number of partitems, and simplify the constitution. CONSTITUTION:A roller guide member 21 for rotatable and movably supporting a driven roller 16 between a stand-by position P1 isolated from the peripheral surface 15a of a driving roller upstream of a driving roller axis 15a in the paper sheet conveying direction, and a paper sheet correcting position P2 pressure-contacting the peripheral surface 15b of the driving roller downstream of the driving roller axis 15a in the paper sheet conveying direction, is provided. Then, the driven 16 is frictionally engaged with the tip part of a paper sheet supplied along a paper sheet conveying path 11 in a state where it is positioned at the stand-by position P1 of the roller guide member 21 by its own weight, and moved to the paper sheet conveying position P2 following the paper sheet so that the paper sheet can be brought into pressure-contact with the driving roller 15.

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 for conveying a sheet to a predetermined place while curving the sheet.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional structure of an image forming apparatus incorporating this type of sheet conveying apparatus. In the figure, the paper P sent out from the paper cassette 2 is conveyed along the horizontal conveyance path 39, and the process unit section 3 (photoconductor 4, charger 5, scanner unit 6, developing device 7, transfer device 8).
In, the toner image is transferred to the printing surface based on the image information. The paper P on which the toner image is transferred is fixed by the fixing device 9
Heat and pressure are applied when the toner image passes, and the toner image is thermally fixed on the printed surface. Paper P that has passed through the fixing device 9
Is conveyed by the sheet conveyance device 10P and is ejected to the external ejection receiving portion 19 with the printing surface facing down.

The sheet conveying device 10P has a sheet conveying path 11 in which a curved portion 12 for guiding the sheet P while curving the sheet P is formed.
A driving roller 15 rotatably provided outside the exit portion 13 of the transport path 11 and a driven roller 16 rotatably provided inside the exit portion 13 for pressing the paper P against the driving roller 15. It is configured to include.

By the way, the paper P is curled with the printing surface inside when passing through the curved portion 12 of the paper transport path 11, and is nipped and transported by both rollers 15 and 16 while maintaining that state and ejected. The paper is discharged to the paper receiver 19. Therefore, it is difficult to handle, and subsequent processing (for example, file processing)
May cause problems.

Therefore, conventionally, in order to avoid the above-mentioned inconvenience, as shown in FIG. 5, a sheet conveying apparatus 10P has been proposed which positively utilizes the peripheral surface of the driving roller 15 to correct the curl of the sheet.

The sheet conveying device 10P has two driven rollers 16a and 16b. Driven roller 16a
Has a function of substantially correcting the curled paper P in cooperation with the drive roller 15, and the drive roller shaft center 15a
It is arranged further downstream in the paper transport direction and is configured to press the paper P against the peripheral surface of the drive roller 15 by a spring force. The driven roller 16b serves to guide the leading end of the curled paper P between the driven roller 16a and the drive roller 15, and is arranged a predetermined distance upstream of the driven roller 16a in the paper transport direction. Has been done. Both driven rollers 16a and 16b are rotatably supported by a support member 36, and the support member 36 is urged toward the drive roller 15 by a spring 37.

Therefore, the sheet P curled by being conveyed through the sheet conveying path 11 has its leading end inserted between the driven roller 16b and the driving roller 15 and advances along the peripheral surface of the driving roller 15. After that, it is inserted between the driven roller 16a and the driving roller 15 and pressed against the driving roller 15. As a result, the paper P is transferred to the driven rollers 16a, 1
The sheet is sandwiched and conveyed while being pressed against the peripheral surface of the drive roller 15 between 6b, and is warped by the peripheral surface.

As a result, the curl of the paper P is corrected and the paper P is ejected to the paper ejection receiver 19.

[0009]

By the way, recently, in the image forming apparatus and the like, cost reduction is demanded in order to further increase the demand. It is being pushed forward.

However, in the above-described sheet conveying apparatus 10P, the driven roller (1) is used to correct the curl of the sheet.
6a, 16b) and two rollers (1
6a, 16b) has to be provided with a press-contact mechanism (support member 36, spring 37) in order to press-contact the drive roller 15, which has a drawback that it is difficult to simplify the configuration.

In view of the above-mentioned circumstances, an object of the present invention is to provide a sheet conveying apparatus capable of surely correcting the curl of a sheet, reducing the number of parts, and simplifying the configuration to achieve cost reduction. To provide.

[0012]

SUMMARY OF THE INVENTION A sheet conveying apparatus according to the present invention is capable of being rotationally driven outside a sheet conveying path having a curved portion for guiding the sheet while curving the sheet and an exit portion of the sheet conveying path. In a paper conveyance device including a drive roller provided and a driven roller rotatably provided inside the exit portion of the paper conveyance path and pressing the paper against the drive roller,
A standby position in which the driven roller is separated from the drive roller peripheral surface upstream of the drive roller shaft center in the paper conveying direction, and a paper correction position in pressure contact with the drive roller peripheral surface in the paper transfer direction downstream of the drive roller shaft center. A roller guide portion that rotatably and movably supports the sheet is provided, and the driven roller is conveyed along the sheet conveying path with the driven roller positioned at the standby position of the roller guide portion by its own weight. It is characterized in that it is formed so that it can be frictionally engaged and moved to the sheet correction position following this sheet conveyance to press the sheet against the drive roller.

[0013]

In the present invention having the above-described structure, the paper is curled when it is conveyed along the curved portion of the paper conveyance path. When the curled sheet frictionally engages with the driven roller positioned at the standby position of the roller guide section at the exit of the sheet conveyance path, the driven roller follows the sheet and moves to the sheet straightening position of the roller guide section. Then press the paper against the drive roller. As a result, the sheet is nipped and conveyed by both rollers.

At this time, since the driven roller is located downstream of the shaft center of the driving roller in the sheet conveying direction, the sheet is directly pressed against the peripheral surface of the driving roller by the driven roller.
Even before reaching the portion (pressure contact portion), the peripheral surface of the drive roller is indirectly pressed over a predetermined length range. As a result, the paper is fed backward by the peripheral surface of the drive roller, and the curl is corrected.

When the leading end of the paper is frictionally engaged with the driven roller, the driven roller is positioned at the standby position and separated from the drive roller, so that smooth frictional engagement is ensured and the paper jam. Etc. does not occur.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, the paper transporting device 10 has a basic configuration (paper transporting path 11, drive roller 15, etc.).
Is similar to the conventional example (Fig. 4), and the roller guide (2
1) is provided, and the curled sheet that has been conveyed in the sheet conveying path 11 is curled by being pressed backward against a predetermined length range portion of the peripheral surface of the drive roller 15b without causing a jam by one driven roller 16 and curled. Is configured so that it can be corrected. The same components as those of the conventional example (FIG. 4) are designated by the same reference numerals, and the description thereof will be omitted or simplified.

First, the roller guide portion (21) has a standby position P1 in which the driven roller 16 is separated from the roller peripheral surface 15b upstream of the driving roller shaft center 15a in the sheet conveying direction.
It is rotatably and movably supported between the roller peripheral surface 15b and the paper correction position P2 which is in pressure contact with the roller peripheral surface 15b downstream of the drive roller shaft center 15a.

Specifically, as shown in FIG. 2, the roller guide portion is formed of a roller guide member 21 having elongated holes 22 formed on both sides. This roller guide member 21
The slotted hole 22 of FIG. 1 regulates the shaft portion 16a of the driven roller 16 at the left end portion in the figure to position the roller 16 at the standby position P1, and regulates the shaft portion 16a at the right end portion in the figure to form the sheet. It is provided so that it can be positioned at the correction position P2.

The driven roller 16 is frictionally engaged with the front end of the paper P sent along the paper transport path 11 while being positioned at the left end of the elongated hole 22 of the roller guide member 21 in the figure by its own weight. Then, following the sheet P, the sheet P is moved to the right end portion of the elongated hole 22 in the figure and the sheet P is driven by the drive roller 1.
It is formed so as to be able to press-contact with 5.

Next, the operation of this embodiment will be described. The sheet P is curled when passing through the curved portion 12 of the sheet conveyance path 11. When the curled paper P frictionally engages with the driven roller 16 positioned at the standby position P1 at the exit portion 13 of the paper transport path 11, the driven roller 16 follows the paper P and the length of the roller guide member 21 increases. The hole 22 is moved to be positioned at the sheet correction position P2, and the sheet P is pressed against the drive roller peripheral surface 15b. Therefore, the paper P is nipped and conveyed by the rollers 15 and 16. At this time, the driven roller 16 has the driving roller shaft center 15
Since it is located downstream of a in the sheet conveying direction, the sheet P is directly pressed against the driving roller peripheral surface 15b by the driven roller 16 and has a predetermined length on the driving roller peripheral surface 15b before reaching the portion (pressure contact portion). Indirectly applied over range. As a result, the paper P is reversely warped by the drive roller peripheral surface 15b, and the curl is corrected. Further, the rotational force of the driving roller 15 acts on the driven roller 16 via the paper P, and the driven roller 16 is pressed against the right end portion of the elongated hole 22 of the roller guide member 21 in FIG. Since the sheet P is reliably positioned and held by the sheet P2, the sheet P can be smoothly nipped and conveyed.

When the leading end of the sheet P frictionally engages the driven roller 16, the roller 16 is positioned at the standby position P1 and is separated from the drive roller 15, so that smooth friction engagement is ensured. No paper jams will occur.

However, according to this embodiment, the standby position P1 in which the driven roller 16 is separated from the drive roller peripheral surface 15b upstream of the drive roller shaft center 15a in the sheet conveying direction.
And a roller guide member 2 for rotatably and movably supporting between the drive roller 15 and the sheet correction position P2 which is in pressure contact with the drive roller peripheral surface 15b downstream in the sheet transport direction.
1, the driven roller 16 is positioned at the standby position P1 of the roller guide member 21 by its own weight, and frictionally engages with the leading end of the paper P fed along the paper transport path 11, and this paper P The curl of the paper P can be surely corrected and the number of parts can be reduced because the paper P is moved to the paper correction position P2 and pressed against the drive roller 15. The cost can be reduced by simplifying the configuration.

Further, since the roller guide portion is formed of the support member 21 which is a single member, the number of parts can be further reduced and the structure can be simplified.

[0024]

According to the present invention, the driven roller is separated from the drive roller peripheral surface at the upstream side of the drive roller shaft center with respect to the drive roller shaft center and at the drive roller peripheral position downstream of the drive roller shaft center in the paper transfer direction. A roller guide is provided that rotatably and movably supports the surface and the sheet straightening position that is in pressure contact, and the driven roller is positioned at the standby position of the roller guide by its own weight and along the sheet transport path. It is formed so that it can be frictionally engaged with the leading edge of the fed paper, moved to the paper straightening position following this paper transportation, and pressed against the drive roller, so that the curling of the paper is ensured. It can be corrected, and the cost can be reduced by reducing the number of parts and simplifying the structure.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an example of the present invention.

FIG. 2 is a perspective view for explaining a positional relationship among a driving roller, a driven roller and a roller guide member.

FIG. 3 is a diagram showing how the driven roller is pushed up to the sheet straightening position and presses the sheet against the drive roller.

FIG. 4 is a diagram showing an image forming apparatus in which a conventional sheet conveying apparatus is incorporated.

FIG. 5 is a diagram for explaining a conventional sheet conveying device capable of correcting a curl of a sheet.

[Explanation of symbols]

 10 Paper Conveying Device 11 Paper Conveying Path 12 Bending Part 13 Exit Part 15 Drive Roller 16 Driven Roller 21 Roller Guide Member (Roller Guide Part)

Claims (1)

[Claims] 1. A sheet conveying path formed with a bent portion for guiding the sheet while curving the sheet, a driving roller rotatably driven outside an exit portion of the sheet conveying path, and an exit portion of the sheet conveying path. In a sheet conveying device provided with a driven roller that is rotatably provided inside the roller and presses a sheet against a driving roller, the driven roller is separated from a peripheral surface of the driving roller upstream of the driving roller shaft center in the sheet conveying direction. A roller guide portion that rotatably and movably supports between a position and a sheet correction position that comes into pressure contact with the drive roller peripheral surface downstream of the drive roller shaft center in the sheet conveying direction is provided, and the driven roller is roller by its own weight. With the guide portion positioned at the standby position, it frictionally engages with the leading edge of the paper fed along the paper transport path, follows this paper, and moves to the paper straightening position. Sheet conveying apparatus characterized by being formed so as to be able to press the sheet to the drive roller.