JP2004307080A - Air blasting type sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air blasting type sheet feeder capable of precluding a double feed of transcription paper sheets and performing the feeding of sheets one by one without obstruction. <P>SOLUTION: The air blasting type sheet feeder is equipped with a sheet accommodation part in which transcription sheets are stacked, a multi-hole transport belt driven upon being set over between a pair of rollers, and a suction duct installed inside the belt, wherein the multi-hole transport belt is installed over the sheet accommodation part for transporting transcription sheets in tight attachment to the transport belt by means of suction through the belt generated by the suction duct, and thereby the sheets are handed over to a transporting roller couple located downstream of the belt. In the feeder device, the transport belt is controlled to be stopped driving in the period after handing-over of each sheet to the transporting roller couple till the time when the trailing edge of the sheet passes under the suction duct. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device used in an image forming apparatus, and more particularly, to an air blowing type paper feeding device for feeding paper (transfer paper) to be image-formed one by one by blowing air. It relates to a paper device.
[0002]
[Prior art]
2. Description of the Related Art In an electrophotographic image forming apparatus such as a copier, a facsimile, or a printer, a toner image formed on a photosensitive drum surface is transferred to transfer paper, and the transferred toner image is transferred to the transfer paper surface by heat or pressure. Image formation is performed by fixing. In such an image forming apparatus, of course, it is necessary to feed the transfer sheets one by one.
[0003]
As a paper feeding device for feeding the transfer paper one by one, a multi-hole transport belt (air permeable belt) wound and driven between a pair of rollers is used, and the transfer loaded on a predetermined paper storage unit is used. There is known a method in which air is blown to a leading end portion of a paper in a paper feeding direction, and only the uppermost transfer paper is fed in close contact with the belt using suction force (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-2001-39556 (claims, FIG. 2).
[0005]
[Problems to be solved by the invention]
In a conventionally known air blowing paper feeder as described in Patent Document 1, the upper transfer paper is sucked and conveyed by a permeable belt, and the lower end of the transfer paper is moved to the permeable belt by moving the rear end. When it comes to face directly, at that time, the lower transfer paper is also sucked and the conveyance is started. That is, the inconvenience that the lower transfer sheet is continuously conveyed following the rear end of the upper transfer sheet cannot be avoided, and there is still room for improvement in order to reliably prevent double feeding.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an air-blowing type sheet feeding apparatus in which double feeding of transfer sheets is reliably prevented.
[0007]
[Means for Solving the Problems]
According to the present invention, the multi-hole transport belt includes a paper storage section on which transfer paper is stacked, a multi-hole transport belt wound and driven between a pair of rollers, and a suction duct provided in the belt. Is disposed above the sheet storage unit, and the transfer duct is conveyed while being in close contact with the perforated transport belt by suction through the perforated transport belt by the suction duct, and air blown to a transport roller pair downstream of the belt. In a paper feeder,
The air blowing type, wherein the multi-hole transport belt is controlled so as to stop driving after the transfer paper is delivered to the transport roller pair and before the rear end of the transfer paper passes under the suction duct. A paper feeder is provided.
[0008]
In the present invention,
1. Paper detection means is arranged downstream of the multi-hole transport belt, and based on a transfer paper leading edge detection signal from the detection means, the driving of the multi-hole transport belt is stopped,
2. A blowing duct is provided on the downstream side of the paper storage unit. By the air blowing by the blowing duct, the transfer paper positioned at the highest position of the transfer paper stack stacked in the paper storage unit is fed to the leading end in the paper feeding direction. Side, then the suction paper is suctioned through the multi-hole transport belt by the suction duct, so that the levitated transfer paper is transported while being in close contact with the multi-hole transport belt,
3. The blowing duct is provided with a double feed prevention protrusion, the front end of which is located downstream of the leading end of the stack of transfer paper sheets in the sheet feeding direction with respect to the sheet feeding direction. Being located below the paper feed surface of the multi-hole transport belt,
4. The double feed prevention protrusions are arranged so as to have a distance of 0.01 to 0.5 mm with respect to the sheet feeding surface,
5. The blowing duct is directly blown with air so as to float both sides of the leading end of the stacked transfer paper bundle in the feeding direction, and a central portion of the leading end of the transfer paper bundle in the feeding direction is It is configured so that air is indirectly blown through the paper feeding surface of the multi-hole transport belt or the outer wall surface of the suction duct,
Is preferred.
[0009]
An important feature of the air blowing sheet feeding device of the present invention is that the multi-hole transport belt is configured to be driven intermittently. That is, when the transfer paper on the upper side is sucked and conveyed by the perforated transfer belt and the rear end moves to cause the lower transfer paper to directly face the air permeable belt, the drive of the perforated transfer belt is temporarily stopped at that time. Stop. As a result, the conveyance of the lower transfer paper (double feed following the upper transfer paper) is reliably prevented, while the upper transfer paper is conveyed by a pair of conveyance rollers provided on the downstream side of the belt. , The conveyance is continued as it is.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, which shows a side cross section of an air blowing sheet feeding apparatus of the present invention, the apparatus includes a sheet storage unit 1, a multi-hole conveying belt 3, a blowing duct 5, a suction duct 7, a conveying roller pair 8, and a sheet detecting switch 9. ing.
[0011]
Transfer papers 10 are stacked in the paper storage unit 1. In FIG. 1, the bundle A of the stacked transfer papers 10 has the end faces on the leading end side in the paper feeding direction (indicated by an arrow X) aligned. ing. Although not shown, a bottom plate for supporting the transfer paper bundle A is provided at the bottom of the paper storage unit 1 in exactly the same manner as in a known device, and this bottom plate is urged upward by a spring or the like. Thus, even when the number of the transfer papers 10 is reduced, the top is always positioned at an appropriate height.
[0012]
The perforated transport belt 3 is known per se, has a large number of suction holes (not shown), and is provided with a pair of rollers 14, 14 (one is a driving roller and the other is a driven roller). The transfer paper bundle A is stretched and is located above the end in the paper feeding direction of the transfer paper bundle A stacked in the paper storage unit 1. The number of the perforated transport belts 3 may be one, but in this example, as shown in FIG. 3 described later, four perforated transport belts 3 are stretched in parallel with rollers 14 at an appropriate interval. Have been.
[0013]
A suction duct 7 is disposed in a portion surrounded by the multi-hole transport belt 3 (hereinafter, simply referred to as the inside of the belt). The suction duct 7 has a suction port 7a, and causes the transfer paper 10 located at the uppermost position of the transfer paper bundle A to be held in close contact with the belt 3 by suction pressure. That is, the uppermost transfer sheet 10 held in close contact with the belt 3 is conveyed in the sheet feeding direction X by driving the belt 3, transferred to the conveying roller pair 8, and fed to a predetermined area by the roller pair 8. Things.
[0014]
On the other hand, the blowing duct 5 is arranged at a small interval on the front surface (the surface in the paper feeding direction X) of the paper storage unit 1, and a guide surface 18 is provided at the upper end in the paper feeding direction X side. Is formed. That is, the leading end portion of the transfer paper 10 that is transported in close contact with the multi-hole transport belt 3 and discharged from the belt 3 is introduced between the transport roller pair 8 by the guide surface 18.
[0015]
Referring to FIG. 2 which shows a perspective view of the blowing duct 5, the blowing duct 5 includes a fan 20 and a duct pipe 22 is connected to the fan 20. That is, the duct tube 22 is located so as to face the upper portion of the front surface of the sheet storage unit 1, and the above-described guide surface 18 is formed on the upper surface of the duct tube 22.
[0016]
The duct tube 22 has first blowing ports 24 for directly blowing air at both ends in the width direction of the transfer paper bundle A, and indirect air flows above the both ends in the width direction of the transfer paper bundle A. And second blowing ports 26, 26 for blowing air.
[0017]
Referring to FIGS. 1 and 2, a relatively large air volume is blown in a substantially horizontal direction by first blowing ports 24, 24, whereby transfer paper 9 positioned above transfer paper bundle A is transferred. Becomes rippling. On the other hand, as is clear from FIG. 2, the second blowing ports 26, 26 are inclined, so that air is not directly blown on the upper portion of the transfer paper bundle A, and once the paper feeding surface (the most The upper transfer paper 10 is blown onto the surface on the side where the transfer paper 10 comes into close contact with) or the outer wall surface of the suction duct 7, and the reflected wind is blown onto the upper part of the transfer paper bundle A. For this reason, air is blown downward to the center portion in the width direction of the transfer paper bundle A.
[0018]
Accordingly, the transfer paper 10 located above the transfer paper bundle A is wavy when the air is blown from the first blowing ports 24, 24 at both ends in the width direction. A downward airflow is blown from the second blowing ports 26, 26 to the central portion in the direction. As a result, air flows between the uppermost transfer paper (indicated by 10a in FIG. 1) and the lower transfer paper (indicated by 10b in FIG. 1). The transfer paper 10a and the transfer paper 10b are separated at the leading end.
[0019]
Further, when a part of the uppermost transfer paper 10a comes into contact with the paper feeding surface of the multi-hole transport belt 3 by waving, the part is held as it is by the suction force on the paper feeding surface, and as a result, the uppermost transfer paper 10a Only the entire surface is brought into close contact with the sheet feeding surface of the perforated conveying belt 3 and is conveyed and fed by the belt 3.
[0020]
By configuring the blowing duct 5 as described above, it is possible to prevent two or more transfer papers 10 from being conveyed in an overlapping state. Is difficult to do. That is, as shown in FIG. 1, when the transfer paper 10a positioned at the uppermost position is conveyed and the trailing end moves, the lower transfer paper 10b is moved through the suction conveyance belt 3 through the porous conveyance belt 3. 7 faces the suction port 7 a and comes into close contact with the multi-hole transport belt 3. As a result, the lower transfer paper 10b is conveyed continuously to the rear end of the uppermost transfer paper 10a.
[0021]
Therefore, in the present invention, after the leading end of the uppermost transfer paper 10a is transferred to the conveying roller pair 8 and before the rear end of the transfer paper 10a passes through the suction port 7a of the suction duct 7 (see FIG. 1). , A), the driving of the multi-hole transport belt 3 is temporarily stopped. That is, when the driving of the multi-hole transport belt 3 is stopped in this way, the uppermost transfer paper 10a is directly transported by the transport roller pair 8, but the lower transfer paper 10b is removed by the suction duct 7. , The belt 3 is stopped, but the inconvenience that the lower transfer paper 10b is conveyed continuously to the rear end of the upper transfer paper 10a is effectively avoided. It is done.
[0022]
In the present invention, the timing control for stopping the driving of the multi-hole transport belt 3 described above can be easily performed by using the sheet detection switch 9 disposed downstream of the transport roller pair 8. That is, when the leading end of the transfer paper 10a is detected by the switch 9, the driving roller 14 of the belt 3 may be stopped at the same time or with a certain time lag. The roller 14 may be driven again after a certain time lag, and the conveyance by the belt 13 may be resumed. The paper detection switch 9 may be provided in a region between the multi-hole transport belt 3 and the transport roller pair 8.
[0023]
As the paper detection switch, for example, an actuator or the like can be used, or an optical sensor can be used, and any structure can be used as long as the passage of the leading end of the transfer paper 10 can be detected reliably. May be. Further, while the multi-hole transport belt 3 is temporarily stopped, the suction duct 7 can be stopped. However, in general, it is preferable that the suction duct 7 is continuously driven. is there.
[0024]
Further, in the present invention, even in a case where the upper transfer paper 10a and the lower transfer paper 10b are stuck to each other by static electricity, the duct pipe 22 is required to prevent double feeding of both. It is desirable to provide the projections 30 for preventing double feed.
[0025]
Referring to FIG. 3 for describing the function of the double feed preventing projections 30, 30, as is apparent from FIG. 3, each of the projections 30, 30 has an upper end provided with a porous conveying belt. 3, and the distance d between each protruding piece 30 and the paper feeding surface of the belt 3 is set in a range of 0.01 to 0.5 mm. The distance d is approximately equal to or slightly larger than the thickness of substantially one sheet of the transfer paper 9. By arranging the projections 30 in this manner, double feeding can be reliably prevented. That is, only the uppermost transfer paper 10a that is in close contact with the multi-hole transport belt 3 passes through the gap between the upper end of the protruding piece 30 and the paper feeding surface of the belt 3, and the uppermost transfer paper 10a is transferred to the lower transfer paper 10b. Even if the transfer paper 10 is in close contact, the transfer paper 10b is reliably blocked by the protruding piece 30.
[0026]
In the present invention, if the distance d between the upper end of the protruding piece 30 and the paper feeding surface of the belt 3 is larger than the above range, the lower transfer paper 10b in close contact with the uppermost transfer paper 10a conveyed by the belt 3 also The frequency of slipping through the gap between the upper end of the protruding piece 30 and the paper feeding surface of the belt 3 increases, and the reliability of preventing double feed decreases. Naturally, if the gap d is smaller than the above range, the uppermost transfer paper 10a that is in close contact with the paper feeding surface of the belt 3 also causes the gap between the upper end of the protruding piece 30 and the paper feeding surface of the belt 3 to move. It will be difficult to slip through.
[0027]
In addition, even when the protruding pieces 30 are arranged in a region between the plurality of perforated transport belts 3, the reliability of preventing double feeding is reduced. That is, in this case, since the belt 3 does not exist above the protruding piece 30, the uppermost transfer paper 10a conveyed in close contact with the paper feeding surface of the belt 3 is suctioned above the protruding piece 30. It is in a state of being slightly upwardly bent by the force. Therefore, if the lower transfer paper 10b is in close contact with the uppermost transfer paper 10a, the transfer paper 10b also bends upward at the upper portion of the protruding piece 30, and together with the uppermost transfer paper 10a. This is because it passes over the protruding piece 30.
[0028]
In the above-described example, the multi-feed preventing protrusion 30 is disposed below the inner two conveyor belts 3 among the four porous conveyor belts 3. All three may be provided on the lower side, and the number is not particularly limited. However, the transfer paper 10 to be conveyed is preferably arranged symmetrically with respect to the center in the width direction. For example, in the case where the number of the perforated conveyance belt 3 is one, one double feed prevention projection piece is provided at the center thereof. Preferably, 30 is provided.
[0029]
The above-described air blowing type sheet feeding apparatus of the present invention may be mounted inside an image forming apparatus such as a copying machine, or may be externally mounted. In addition, not only the image forming apparatus but also an apparatus such as a scanner can be used as an apparatus for feeding a document to be read to a predetermined area.
[0030]
【The invention's effect】
According to the above-described present invention, it is possible to more reliably prevent the overlap feeding of a plurality of transfer papers, that is, the double feed, as compared with a conventionally known device, and further, the transfer of the transfer paper for each sheet is not performed at all. It can be performed without hindrance.
[Brief description of the drawings]
FIG. 1 is a diagram showing a side cross section of an air blowing sheet feeding device of the present invention.
FIG. 2 is a perspective view of a blowing duct provided in the sheet feeding device of FIG.
FIG. 3 is a view showing a relationship between a multi-feed preventing projection provided on the blowing duct of FIG. 2 and a multi-hole transport belt.
[Explanation of symbols]
1: paper storage unit 3: multi-hole transport belt 5: blowing duct 7: suction duct 8: transport roller pair 9: paper detection switch 10: transfer paper 10a: uppermost transfer paper 10b: uppermost lower transfer paper 30 ： Protrusion for preventing double feed

Claims (6)

A paper storage unit on which transfer paper is loaded, a multi-hole transport belt wound and driven between a pair of rollers, and a suction duct provided in the belt; In the air blowing type paper feeder, which is disposed on the upper side and conveys the transfer paper while being in close contact with the multi-hole transport belt by suction through the multi-hole transport belt by the suction duct, and transfers the transfer paper to a pair of transport rollers downstream of the belt. ,
The air blowing type, wherein the multi-hole transport belt is controlled so as to stop driving after the transfer paper is delivered to the transport roller pair and before the rear end of the transfer paper passes under the suction duct. Paper feeder. 2. The air blower according to claim 1, wherein a sheet detection unit is disposed downstream of the multi-hole transport belt, and the driving of the multi-hole transport belt is stopped based on a transfer paper leading edge detection signal from the detection unit. 3. Attached paper feeder. A blowing duct is provided on the downstream side of the paper storage unit. By the air blowing by the blowing duct, the transfer paper positioned at the uppermost position of the transfer paper stack stacked in the paper storage unit is fed to the leading end in the paper feeding direction. 3. The air blowing type sheet feeding device according to claim 1, wherein the transfer paper floats on the side and is then conveyed while being closely attached to the perforated transport belt by suction through the perforated transport belt by the suction duct. 4. . The blowing duct is provided with a double feed prevention protrusion, and the protrusion is located downstream of the leading end of the stack of transfer paper sheets in the sheet feeding direction with respect to the sheet feeding direction. 4. The air blowing type sheet feeding device according to claim 1, wherein the sheet is located below a sheet feeding surface of the multi-hole conveyance belt. The air blowing type sheet feeding device according to claim 4, wherein the double feed prevention projection is disposed so as to have a distance of 0.01 to 0.5 mm from the sheet feeding surface. In the blowing duct, air is directly blown onto the loaded transfer paper bundle in such a manner as to levitate both sides of the leading end of the transfer paper bundle in the paper feeding direction. The air blowing type sheet feeding device according to any one of claims 3 to 5, wherein air is blown indirectly through a sheet feeding surface of the multi-hole transport belt or an outer wall surface of a suction duct.

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