JP2004010240A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device with a paper ejecting device that can implement a good alignment of paper by eliminating static electricity of the paper assuredly for any type or size of paper. <P>SOLUTION: In addition to a first static eliminator 16a placed close to the downstream side of a paper ejecting roller pair 4, there is provided a second static eliminator 16b spaced away from the eliminator 16a and a structure of a mechanism portion of the pair 4, and placed on a paper guide 17 introducing paper 1 to the downstream side in a direction perpendicular to a direction of paper movement. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine and a laser beam printer.
[0002]
[Prior art]
As is well known, in a paper ejection device of an image forming apparatus, in consideration of post-processing such as bookbinding and bookbinding, paper is not unevenly arranged in a paper traveling direction and a direction perpendicular to the paper traveling direction (paper width direction). Need to be aligned.
[0003]
Therefore, conventionally, as shown in FIG. 2, the static electricity charged on the paper 1 discharged from the paper discharge roller pair 4 of the paper discharge device 2 of the image forming apparatus 3 is caused by bringing the paper 1 into contact with the leading end of the static eliminator 16a. A method is adopted in which the paper 1 is removed and the paper 1 is aligned on the paper loading table 6 by a rotating member 9 that presses the rear end of the paper 1 on the paper loading table 6 in the vertical direction.
[0004]
[Problems to be solved by the invention]
However, in the above-described means, since the static eliminator is disposed immediately after the discharge roller pair, the static eliminator is close to a conductor such as a metal constituting a mechanical unit of the discharge roller pair, so that the static elimination effect on the paper is reduced. May decrease. If the static eliminator removes the static electricity from the paper incompletely, the trailing edge of the paper pressed by the rotating member onto the paper loading table will rise again on the paper transport path due to the static electricity remaining on the paper, and will be discharged from the succeeding part. The paper collided with the leading edge of the incoming paper, causing paper jam and deterioration of the alignment of the paper.
[0005]
Further, even when the trailing edge of the sheet does not rise, the sheet on the sheet stacking table may move due to static electricity, so that it has been difficult to ensure the alignment of the sheet.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which avoids the above-mentioned problems and realizes good alignment of sheets discharged into a sheet discharging apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in addition to the first static eliminator disposed downstream of the discharge roller pair, the first static eliminator and the discharge roller pair are separated from the structure. A second static eliminator was provided.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment will be described below with reference to FIG. A sheet discharge roller pair 4 provided in a sheet discharge device 2 for sending out a sheet 1 fed from a sheet discharge roller pair (not shown) provided in the image forming apparatus 3 to the next stage is supported movably up and down. A stack table 6 for stacking and storing sheets sent from the sheet discharge roller pair 4, a table driving mechanism (not shown) for raising and lowering the stack table 6, a control device for controlling the table driving mechanism, and sheets A sheet guide 17 for introducing the sheet 1 to the downstream side in the sheet traveling direction; and a sheet aligning member 8 disposed at the downstream side in the sheet traveling direction and reciprocating in the traveling direction of the sheet 1 discharged onto the stack table 6 to align the leading end of the sheet 1. And a paper top pressing roller 5 for pressing the top surface of the leading end of the paper 1, and a paper trailing end stopper arranged at the upstream side in the paper advancing direction to align the trailing end of the paper 1 discharged onto the stack table 6. 15, a rotating member 9 disposed above the stack table 6 and pressing the upper surface of the rear end of the sheet 1 discharged onto the stack table 6 in a vertical direction, and a rotating member 9 arranged parallel to the sheet traveling direction and Sheet aligning member 7 for reciprocating in the orthogonal direction (sheet width direction) to align the sheets 1, stacked sheet upper surface detecting means 10 for detecting the uppermost position of the sheet, and the sheet advancing direction near the downstream side of the discharge roller pair 4. A first static eliminator 16a disposed in a direction perpendicular to the first direction to remove static electricity from the sheet 1, and a second static electricity remover 16a provided downstream of the static eliminator 16a in a direction perpendicular to the sheet traveling direction to further eliminate static electricity in the sheet 1 And the static eliminator 16b. The stack table 6 is detachably provided on a vertically movable table arm 11. When a predetermined amount of paper is stacked on the stack table 6, the stack arm 6 is moved from the table arm 11 to the stack table 6. Care has been taken to allow removal and transport by the operator.
[0009]
Here, when the sheet 1 charged with the static electricity is conveyed into the sheet ejection device by the sheet ejection roller pair 4, the static electricity is first removed by the first static eliminator 16a. Furthermore, the residual static electricity that could not be removed by the first static eliminator 16a by the second static eliminator 16b arranged at a position where the electrical influence from the structure of the first static eliminator 16a and the paper discharge roller pair 4 was small. , The trailing edge of the sheets 1 stacked on the stack table 6 can be prevented from floating on the sheet transport path, and the top of the sheets 1 stacked on the stack table 6 due to remaining static electricity can be prevented. Irregularities can be prevented.
[0010]
Further, by bringing the sheet 1 sent from the sheet discharge roller pair 4 into contact with the second static eliminator 16b by about 1 to 3 mm, the static electricity can be reliably removed and the sheet 1 can be quickly conveyed in the vertical downstream direction. As a result, an air layer is less likely to be formed in the stacked sheets, and good alignment of the sheets can be achieved. The second static eliminator 16b is provided on the paper guide 17 in a direction perpendicular to the paper advancing direction, and the contact angle with the paper 1 is set to 60 ° or less. In any discharge mode, such as a discharge mode in which the paper is upwardly curled with a large upward curl, it is possible to reliably remove static electricity and maintain good alignment of the paper.
[0011]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an image forming apparatus including a sheet discharging device capable of reliably removing static electricity from a sheet regardless of the type and size of the sheet and achieving good sheet alignment. it can.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a paper discharge device of an electrophotographic printing apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a paper discharge device of an electrophotographic printing apparatus showing an embodiment according to a conventional technique.
[Explanation of symbols]
1 is a sheet, 2 is a sheet discharging device, 3 is an image forming apparatus, 4 is a sheet discharging roller pair, 5 is a sheet upper surface pressing roller, 6 is a stack table, 7 is a sheet aligning member, 8 is a sheet aligning member, and 9 is a rotation. Reference numeral 10 denotes a stacked paper upper surface detecting unit, 11 denotes a table arm, 12 denotes a motor, 13 denotes a power transmission belt, 14 denotes a drive shaft, 15 denotes a paper trailing end stopper, 16a denotes a first neutralization brush, and 16b denotes a second. A neutralizing brush 17 is a paper guide.

Claims (3)

A sheet discharge roller pair connected downstream of the image forming apparatus and feeding the printed sheet sent from the image forming apparatus downstream, a sheet guide for introducing the sheet downstream in the sheet traveling direction, and the sheet A sheet loading table for stacking and storing, a table driving mechanism for raising and lowering the sheet loading table, a control device for controlling the table driving mechanism, and an upper surface detecting unit for detecting a top surface position of the sheet, A sheet aligning member disposed reciprocally in the sheet advancing direction of the sheet discharged on the sheet loading table disposed downstream of the sheet advancing direction; a sheet aligning member disposed upstream in the sheet advancing direction; An image forming apparatus comprising: a pair of sheet aligning members reciprocating in a direction orthogonal to a traveling direction; and a sheet discharging device having a driving mechanism for each of the sheet aligning members. A first static eliminator arranged in the direction perpendicular to the sheet traveling direction near the downstream side of the pair, and an entrance portion of the paper guide arranged downstream of the first static eliminator in the sheet traveling direction. An image forming apparatus, comprising: a second static eliminator arranged in a perpendicular direction. The front end of the second static eliminator is arranged at a position separated from the first static eliminator by 15 mm or more, and there is no structure between the first static eliminator and the first static eliminator. Image forming device. 2. The image forming apparatus according to claim 1, wherein the tip of the second static eliminator contacts a sheet fed from the sheet discharging roller pair and has a contact angle of 60 ° or less. 3.

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