JP2006298551A - Paper sheet aligning mechanism for image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet aligning mechanism of simple structure to be manufactured at low costs and improved in operation efficiency. <P>SOLUTION: This paper sheet aligning mechanism 2 for an image forming device is provided with a pair of paper sheet conveying rollers 8 and two paper sheet aligning arm members 10. Each of the paper sheet aligning arm members 10 is positioned so that a tip 10a thereof is projected by a tensile coil spring 14 in a paper sheet conveying passage 3 at a position just upstream of a nip part 8N of the pair of paper sheet conveying rollers 8. When paper sheets P are conveyed from the upstream side in such a state that the pair of paper sheet conveying rollers 8 are driven for rotation, the paper sheet P is prevented from skewing, nipped by the pair of paper sheet conveying rollers 8, and conveyed without stopping. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a pair of sheet conveying rollers disposed in a sheet conveying path in an image forming apparatus such as an electrophotographic copying machine, a laser printer, and a facsimile, and a shaft disposed upstream of the pair of sheet conveying rollers. The present invention relates to a sheet aligning mechanism of an image forming apparatus including at least two sheet aligning arm members that are rotatably supported and spaced apart in a width direction orthogonal to a sheet conveying direction.

The paper alignment mechanism of the above form is disclosed in, for example, Patent Document 1. The paper aligning mechanism disclosed in Patent Document 1 has a swinging member that swings with a width greater than the swinging width of the gate member in conjunction with a gate member disposed in a paper aligning device provided in the paper transport path. The buffer member is disposed corresponding to the end of the swing range of the swing member, and the swing width of the gate member is regulated via the swing member whose swing range is regulated by the buffer member. It is comprised so that the means to perform may be provided.

According to the sheet aligning mechanism, it is possible to align the sheet by bringing the leading end of the sheet conveyed through the sheet conveying path into contact with the gate member and stopping the sheet. However, in the sheet aligning mechanism, the gate member is caused to appear and retract with respect to the sheet conveyance path by a driving unit such as a solenoid, so that the configuration becomes complicated and the cost increases. In addition, since the conveyed paper is once stopped by the gate member, the operation efficiency of the image forming apparatus is reduced accordingly.
Japanese Patent Laid-Open No. 08-119498

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel sheet alignment mechanism of an image forming apparatus that can be manufactured at a low cost with a simple structure and that can improve the operation efficiency.

According to the present invention,
A pair of sheet conveying rollers disposed in the sheet conveying path of the image forming apparatus and a rotation shaft disposed on the upstream side of the pair of sheet conveying rollers are supported so as to be integrally rotatable and in the sheet conveying direction. In a sheet alignment mechanism of an image forming apparatus, comprising at least two sheet alignment arm members arranged at an interval in an orthogonal width direction,
Each of the sheet alignment arm members is positioned by the rotational moment applying means so that the leading end protrudes into the sheet conveyance path at a position immediately upstream of the nip portion of the sheet conveyance roller pair, and the sheet conveyance roller pair is rotationally driven. When the sheet is conveyed from upstream, the leading ends of the sheets are sequentially brought into contact with the respective leading end portions of the sheet aligning arm members and aligned, and each of the sheet aligning arm members is moved by the leading end of the sheet. The leading end of the sheet is rotated against the rotational moment applying means so that the leading end is retracted from the sheet conveying path, and the leading end of the sheet is nipped by a pair of rotating sheet conveying rollers. , Transported without stopping,
A sheet aligning mechanism for an image forming apparatus is provided.
It is preferable that the rotational moment applying means is composed of a tension coil spring.
The base end portion of each of the paper alignment arm members opposite to the front end portion is rotatably supported by the shaft, and the rotation moment applying means is provided from each base end portion of the paper alignment arm member to the front end portion. It is preferable that it consists of the weight part extended in the opposite direction.

Preferred embodiments of a sheet alignment mechanism of an image forming apparatus constructed according to the present invention will be described below in detail with reference to the accompanying drawings.

1 to 3, the sheet alignment mechanism 2 is provided in an image forming apparatus (not shown). For example, an image forming apparatus such as a laser printer is provided with an image forming unit including a photosensitive drum, a main charger, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. The paper alignment mechanism 2 is disposed at the downstream end of the upper guide plate 4 and the lower guide plate 6, and the upper guide plate 4 and the lower guide plate 6 that constitute a part of the paper transport path 3 on the upstream side of the photosensitive drum. And a pair of paper transport rollers 8. The upper guide plate 4 and the lower guide plate 6 are disposed so as to extend horizontally at intervals in the vertical direction. The pair of paper conveying rollers 8 includes a driving roller 8A disposed integrally with the shaft 8a and a driven roller 8B disposed integrally with the shaft 8b. The shafts 8 a and 8 b of the paper transport roller pair 8 are arranged in parallel and horizontally with each other so as to be orthogonal to the paper transport path 3. The shaft 8a of the driving roller 8A is drivingly connected to a driving source such as an electric motor (not shown).

The sheet aligning mechanism 2 also includes at least two sheet aligning arm members 10, and in the embodiment, two sheet aligning arm members 10. Each of the sheet alignment arm members 10 is supported so as to be able to rotate integrally with a rotation shaft 12 disposed upstream of the pair of sheet conveying rollers 8 and below the upper guide plate 4 and the lower guide plate 6. In addition, they are arranged at intervals in the width direction orthogonal to the paper transport direction (the direction indicated by the arrow in FIGS. 1 and 2, the direction from right to left in FIG. 3).

Each of the sheet aligning arm members 10 made of mutually common components is formed of a synthetic resin having a relatively light weight and a small friction coefficient. 8 is positioned so as to protrude into the sheet conveyance path 3 at a position immediately upstream of the nip portion 8N. The rotating shaft 12 is made of a relatively lightweight synthetic resin, and both ends thereof are rotatably supported by bearings (not shown). The leading end of each leading end portion 10a of the paper alignment arm member 10 is formed in a semicircular shape. The interval between the sheet alignment arm members 10 is defined such that both ends of the sheet P, which is the smallest dimension in the width direction of the sheet P to be conveyed, can come into contact with each other. As shown in FIG. 3, each of the sheet alignment arm members 10 is supported so that a base end portion 10 b opposite to the tip end portion 10 a can rotate integrally with the rotation shaft 12. As shown in FIG. 3, each of the sheet alignment arm members 10 includes a base end portion 10 b, a base end portion 10 b toward the downstream side in the transport direction of the paper P, and upward toward the paper transport path 3. A main body portion 10c extending in an inclined manner and a front end portion 10a protruding substantially vertically from the front end of the main body portion 10c so as to be orthogonal to the paper transport path 3 are provided. The home position of each of the paper alignment arm members 10 is defined by a stopper 16. On each rotation trajectory of the sheet alignment arm member 10, the driving roller 8A and the driven roller 8B do not have discontinuous portions in the axial direction, that is, the driving roller 8A and the driven roller 8B. A portion where 8b is exposed is formed, and is configured so as not to interfere with a predetermined range of rotation in each of the sheet alignment arm members 10.

A paper feed cassette, a pickup roller, a separation roller pair, and the like are disposed at the upstream end of the sheet conveyance path 3, and another conveyance roller pair is disposed in the sheet conveyance path 3 between the separation roller pair and the sheet alignment mechanism 2. Is arranged. Further, on the downstream side of the photosensitive drum, a fixing device, a conveyance roller, a discharge roller, and the like are disposed along the sheet conveyance path. A paper discharge tray is disposed on the downstream side of the discharge roller (both not shown).

When the paper P is transported from the paper feed cassette disposed at the upstream end of the paper transport path 3 in a state where the paper transport roller pair 8 is rotationally driven, the leading edge of the paper P is moved to each of the paper alignment arm members 10. The tips are sequentially brought into contact with the tip portions to be aligned. That is, as shown in FIG. 2, the leading end of the sheet P conveyed obliquely is first brought into contact with one sheet alignment arm member 10. Subsequently, the leading edge on the delay side is brought into contact with the other paper aligning arm member 10 so that the skew of the paper P is aligned in a correct posture.

At the same time, each of the sheet aligning arm members 10 resists the spring force of the tension coil spring 14 so that the leading end 10a is retracted downward from the sheet conveying path 3 by the leading end of the sheet P to be conveyed in FIG. It is rotated integrally with the rotating shaft 12 in the counterclockwise direction. The paper P is transported without being stopped by the nipping of the leading end portion of the paper P by the pair of paper transport rollers 8 that are rotationally driven (see FIG. 5). The sheet P aligned by the sheet aligning mechanism 2 as described above is conveyed in the downstream direction by the sheet conveying roller pair 8 and passed through between the photosensitive drum and the transfer unit, as is well known on one side. The toner image is transferred to the toner image. The toner image is fixed on the paper P on which the toner image is transferred while passing through the fixing device. The paper P on which the toner image is fixed is conveyed along a paper conveyance path by a conveyance roller, and is discharged to a paper discharge tray by a discharge roller. When the trailing edge of the paper P passes through the nip portion 8N of the paper conveying roller pair 8, each of the paper alignment arm members 10 is returned to the home position shown in FIG. It is provided for alignment of the conveyed paper P.

According to the sheet aligning mechanism 2 according to the present invention, the skewed sheet P is nipped by the sheet conveying roller pair 8 and conveyed without stopping while being aligned in a correct posture during conveyance. Can improve the operating efficiency. In addition, since a driving means such as a solenoid for driving each of the paper alignment arm members 10 is not required, the configuration is simple and the manufacturing can be performed at low cost. Further, as in the conventional registration roller pair, it is not necessary to stop and rotate the registration roller pair each time the paper P is conveyed, and the clutch mechanism for that purpose can be omitted, so that the control can be performed. In addition, the structure can be further reduced in size and cost.

In the above embodiment, the rotation moment applying means is constituted by the tension coil spring 14, but instead of this, as shown by a two-dot chain line in FIG. There is another embodiment in which the weight portion 10d extends from the end portion 10b in the direction opposite to the tip portion 10a. As can be easily understood from the above description, these rotational moment applying means have a function of applying a resistance force for aligning the paper P to each of the paper aligning arm members 10 and the paper P passes therethrough. After that, each of the sheet alignment arm members 10 has a function of returning to the home position.

1 is a perspective view showing an embodiment of a paper alignment mechanism of an image forming apparatus configured according to the present invention. FIG. 2 is a perspective view illustrating a state in which a sheet is conveyed in the sheet alignment mechanism of the image forming apparatus illustrated in FIG. 1. FIG. 3 is a configuration diagram of a sheet alignment mechanism of the image forming apparatus illustrated in FIG. 2 as viewed from the side. FIG. 4 is a configuration diagram illustrating another operating state of the sheet alignment mechanism of the image forming apparatus illustrated in FIG. 3. FIG. 10 is a configuration diagram illustrating still another operating state of the sheet alignment mechanism of the image forming apparatus illustrated in FIG. 3.

Explanation of symbols

2: paper alignment mechanism 3: paper conveyance path 4: upper guide plate 6: lower guide plate 8: conveyance roller pair 10: paper alignment arm member 10
10a: distal end portion 10b: proximal end portion 10d: weight portion 12: rotating shaft 14: tension coil spring 16: stopper P: paper

Claims (3)

A pair of sheet conveying rollers disposed in the sheet conveying path of the image forming apparatus and a rotation shaft disposed on the upstream side of the pair of sheet conveying rollers are supported so as to be integrally rotatable and in the sheet conveying direction. In a paper alignment mechanism of an image forming apparatus, comprising at least two paper alignment arm members arranged at intervals in the orthogonal width direction,
Each of the sheet alignment arm members is positioned by the rotational moment applying means so that the leading end protrudes into the sheet conveyance path at a position immediately upstream of the nip portion of the sheet conveyance roller pair, and the sheet conveyance roller pair is rotationally driven. When the sheet is conveyed from upstream, the leading ends of the sheets are sequentially brought into contact with the respective leading end portions of the sheet aligning arm members and aligned, and each of the sheet aligning arm members is moved by the leading end of the sheet. The leading end of the sheet is rotated against the rotational moment applying means so that the leading end is retracted from the sheet conveying path, and the leading end of the sheet is nipped by a pair of rotating sheet conveying rollers. , Transported without stopping,
A sheet aligning mechanism for an image forming apparatus. The sheet aligning mechanism of the image forming apparatus according to claim 1, wherein the rotation moment applying means includes a tension coil spring. The base end portion of each of the paper alignment arm members opposite to the front end portion is rotatably supported by the shaft, and the rotation moment applying means is provided from each base end portion of the paper alignment arm member to the front end portion. The sheet aligning mechanism of the image forming apparatus according to claim 1, further comprising a weight portion extending in a direction opposite to the first direction.

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