JPH11212311A - Document feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a document to be separated and fed by small torque, to prevent it from being fed by being superposed or soiled, to enhance reliability and to reduce a cost by reducing frictional resistance between the document imposed on a separation member. SOLUTION: This document feeder is provided with a document table 12, an access roller 14 accessing a document bundle P set on the table 12 to a downstream side, a paper supply belt 15 and a reverse roller 16 constituting a separation means separating the document from the bundle P and interposing it at a nip part one by one and feeding it out to the downstream side and a driven roller 17 interposing the document P between a driven roller 17a (17b) and feeding it to a contact glass. Besides, it is provided with a guide plate 18 having a slidable contact surface 18 for guiding the lower surface of the document P so as to straightly pull it out from the nip part between the belt 15 and the roller 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original feeder for separating and feeding originals one by one from a set of originals, and more particularly, to processing of a fed original by an apparatus body below an original table. It relates to a device that automatically feeds paper to a position.

[0002]

2. Description of the Related Art Conventionally, copiers and facsimile machines which read and process an image from a document have been equipped with a document feeder for automatically feeding a document.
This document feeder improves the convenience of the apparatus main body by separating the documents to be processed from the document bundle set on the document table one by one and feeding the separated documents to a processing position by the apparatus main body.

In general, this type of document feeder has a document table which is disposed above a processing position of the apparatus main body so as to be mounted on the apparatus main body with a small installation area. The document separated from the document bundle on the document table is constructed to be sent downward, turned over, and fed to the processing position. Separation of originals from the original stack
The separation member, which is driven in the opposite direction to the sheet feeding direction, slides on the lower surface of the document to apply a load in a direction of returning the document other than the uppermost one to the document table, and the sheet feeding member driven in the sheet feeding direction is used for the document. In some cases, the uppermost document is fed one sheet at a time in the sheet feeding direction by being pressed against the upper surface of the document.

[0004]

However, in such a conventional document feeder, the document to be separated from the document bundle on the document table is pulled downward immediately after the separation position to remove the document from the apparatus body. When the separation member that is driven in the opposite direction to the paper feeding direction slides on the lower surface of the original, the original slides on the separation member with a large area to apply a large frictional resistance. . For this reason, the motor that drives the separating member must select a motor that drives with a torque larger than the frictional resistance.
This hinders miniaturization and cost reduction.

The separating member receives a driving force via a torque limiter. For example, when the last original is fed, the separating member is subjected to frictional resistance with the original pressed against the original. The limit value is set so as to follow the rotation. However, even though the document is not the last document, if the torque limiter operates and the driven document is rotated by a large frictional resistance with the document, the remaining document is sent to the nip portion between the document and the paper feeding member, and the weight of the document is reduced. There is a possibility that the paper may be fed or stained.

Accordingly, the present invention realizes separation and feeding of originals with a small torque by reducing the frictional resistance between the originals applied to the separating member and small originals, and prevents double feeding and contamination of the originals, thereby improving reliability. It aims at improvement and cost reduction.

[0007]

According to one aspect of the present invention, there is provided a document table in which a bundle of a plurality of documents can be set, and a call for calling a document bundle on the document table to a downstream side. Means, separating means for separating the originals one by one from the called bundle of originals one by one at a nip portion, holding the originals and sending them downstream, and feeding means for feeding the separated originals to a position below the separating means Wherein the separating means is driven in the direction opposite to the paper feeding direction while slidingly contacting the lower surface of the document, thereby preventing the document from being sent to the paper feeding means other than the uppermost document. It is characterized in that a separating member is provided and guide means for guiding the original is provided so that the original fed by the paper feeding means is pulled straight out of the nip portion of the separating means.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the guide means extends in a direction substantially perpendicular to a direction in which the document is held in the nip by the separating means. And a guide member having a sliding contact surface for guiding the lower surface of the document. According to a third aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the guide means has an outer peripheral top surface positioned in a direction substantially orthogonal to a direction in which the document is nipped at the nip by the separating means. And a guide roller that can be driven and rotated to guide the lower surface of the document.

According to the present invention, the document separated by the separation means and fed by the paper supply means is straightened from the nip portion between the separation member and the paper supply member, and the slide contact surface of the guide member constituting the guide means, After being pulled out while being guided by the guide rollers, it is fed downward by the sheet feeding means. Therefore, the sliding area of the document pulled out from the nip portion of the separating means with the separating member is reduced to approximately the nip portion. At this time, the lower surface of the fed document slides on the sliding contact surface of the guide member, while the guide roller is rotated by the lower surface of the fed document.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of a document feeder according to the present invention.
FIG. 1 is a diagram illustrating an embodiment, and is a diagram illustrating an example mounted on an image reading apparatus that reads an image from a document. This embodiment corresponds to the first and second aspects of the present invention.

In FIG. 1, reference numeral 10 denotes a document feeder mounted on an image reading device provided in an apparatus main body H of a copying machine or a facsimile machine.
Turns over the original P with the image side facing upward on the original table 12 and automatically feeds it onto the large-area contact glass C,
The transport unit 21 receives the document P and contacts the contact glass C.
The image reading apparatus of the apparatus main body H is stopped (placed) at a reading position (processing position) on the upper surface, and the reading glass (not shown) extending in the main scanning direction is reciprocated in the sub-scanning direction, for example, while the contact glass C is being moved. A light is radiated to the image surface of the original P via a CCD, and the reflected light is photoelectrically converted by a reading means such as a CCD to read an image to be copied (exposure).
The original 31 carries out the original P from the contact glass C and discharges it onto the discharge tray 41 or the discharge table 42. The document feeder 10 includes a paper feed unit 11, a transport unit 21, and a paper discharge unit 31.
And a drive motor (not shown) that can be independently driven as a drive source for driving each unit.

The paper feed unit 11 is configured to set a plurality of original bundles P on the original table 12 by abutting the original P against the end of a stop claw 13 hanging down the original table 12 in the paper feeding direction. The stop claw 13 lowers its tip in the direction of the document table 12 during standby, thereby restricting the feeding of the document P before feeding, and allowing the document P to stand by. When a start key (not shown) of the apparatus main body H is pressed in a state in which the original bundle P is set, the paper feed motor starts forward rotation and the call roller 14, the paper feed belt 15, and the reverse roller 16 are rotated clockwise. Then, the pull-out roller 17 is rotated counterclockwise to raise the stop claw 13 to enable the document P to be sent out.
To the nip of the reverse roller 16.

At this time, a plurality of originals P may be sent out by the recall roller 14, but the paper feed belt 15 and the reverse roller 16 that rotate clockwise in a state where they are pressed against each other are
In the nip portion, while the feed belt 15 rotates in the feed direction,
Since the reverse roller 16 rotates in the reverse direction, the uppermost document P is fed by the difference in frictional resistance (between the documents P <between the documents P and the reverse rollers 16 <between the documents P and the feed belt 15).
The originals P are sent out in the paper feeding direction by 15 and the other originals P are returned to the original table 12 by the reverse rollers 16. As a result, the originals P on the original table 12 are separated and fed one by one from the original bundle P. . That is, the calling roller 14 constitutes a calling means, and the reverse roller 16 constitutes a separating member, and constitutes a separating means together with the sheet feeding belt 15 of the sheet feeding member. In addition,
When the last original P is separated and fed, the feeding belt 15
The reverse roller 16 is pressed into contact with the document P, which is an excessively large load, by pressing the reverse roller 16 via one document P. Therefore, the friction resistance of the reverse roller 16 is set to a preset limit value. When it exceeds, the built-in torque limiter operates to allow the reverse roller 16 to be driven to rotate.

The paper feed unit 11 pulls the originals P separated and fed one by one from the pull-out rollers 17 to the driven rollers on the upstream side.
The paper is fed onto the contact glass C pulled out from the nip portion of the paper feed belt 15 and the reverse roller 16 while being sequentially sandwiched between the roller 17a and the driven roller 17b on the downstream side. At this time, when the pull-out sensor S1 disposed downstream of the driven roller 17a detects the leading end of the document P,
The transmission of the driving force to the motor 15 is cut off and the rotation is stopped (the driving direction of the paper feed motor is switched from the normal rotation to the reverse rotation depending on the configuration of the driving system). In the clockwise direction, the pull-out roller 17 is kept rotating counterclockwise, and the feeding of the next original P from the upper side of the original table 12 is prevented by the reverse roller 16 and the current original P which has been separated and fed is contacted by the pull-out roller 17. Feed paper on C. The pull-out sensor S1
Detects the leading edge of the document P, the recall roller 13 rises so as not to press the document P returned by the reverse roller 16. That is, the pull-out rollers 17 are driven rollers 17a, 17
The sheet feeding means is constituted together with b.

The transport section 21 is provided with a call roller 13 of the sheet feeding section 11.
At the same time as the stop of the paper feed belt 15 (when the pull-out sensor S1 detects the leading end of the document P), the conveyance motor starts forward rotation and the winding roller 23 around which the conveyance belt 22 is wound.
Is rotated counterclockwise to move (drive) the transport belt 22 pressed against the contact glass C by the pressure roller 24 in the paper feeding direction. The received document P is conveyed while the image surface is brought into close contact with the upper surface of the contact glass C, and is stopped at the exposure position of the apparatus main body H on the contact glass C. At this time, after the registration sensor S2 detects the rear end of the document P conveyed by the conveyance belt 22, the conveyance motor is driven by a predetermined number of pulses and stopped, thereby stopping the document P at the exposure position on the contact glass C. Then, after the exposure by the apparatus main body H is completed, the transport motor resumes normal rotation, and drives the transport belt 22 in the same direction, thereby transporting the document P from the contact glass C.

The paper discharge unit 31 starts the normal rotation of the paper discharge motor at the same time as the driving of the transport belt 22 to rotate the paper discharge roller 32 counterclockwise. A paper discharge path R formed in accordance with the switching direction of the switching claw 33 by sandwiching the conveyed original P with the driven roller 32a.
1. The paper is discharged onto a paper discharge tray 41 or a paper discharge table 42 via R2. At this time, when the switching claw 33 is positioned upward, the document P sandwiched between the discharge roller 32 and the driven roller 32a is formed by forming the discharge path R1 in the direction of the discharge tray 41.
The paper is ejected on top. When the switching claw 33 is located at a lower position, the document P sandwiched between the discharge roller 32 and the driven roller 32a is formed by forming the paper discharge path 2 in the direction of the paper discharge table 42.
The sheet P can be delivered to the contact glass C by being transferred to the sheet discharge roller 32 and the driven roller 32b through the return path R3 formed by the roller 34, and conveyed again to the exposure position by the conveyance belt 22, thereby exposing the back surface of the document P. The document P carried out after the completion of the process is transferred to the discharge roller 35 and the driven roller 35a via the discharge path R4 formed by the switching claw 34, and is discharged to the discharge table 42.
Paper.

Here, the paper feeding section 11 in the present embodiment is
A guide plate 18 disposed between the nip portion of the paper feed belt 15 and the reverse roller 16 and the pull-out roller 17 extends in a direction substantially orthogonal to the direction in which the document P is held, as shown in FIG. The guide plate 18 is formed so as to form a sliding contact surface 18a for guiding the lower surface of the original P. The guide plate 18 is sandwiched by a pull-out roller 17 and a driven roller 17a, and is a nip portion of the paper feed belt 15 and the reverse roller 16. The sliding surface 18a is mounted so that the lower surface of the original P to be pulled out from the paper feed belt 15 and the reverse roller 16 is guided straight from the nip portion by the reverse roller 16. That is, the guide plate 18 constitutes a guide member constituting the guide means.

Therefore, in the paper supply section 11, the paper supply belt 15
In addition, since the pull-out roller 17 and the driven roller 17a located below hold the original P sandwiched by the reverse roller 16 at the nip portion, the original is pulled out and fed downstream, so that the conventional technique without the sliding contact surface 18a shown in FIG. In the case of the guide plate 19 to be used, the document P is wound around the reverse roller 16 that rotates clockwise at an angle θ1 corresponding to the positional relationship with the pull-out roller 17 to apply a large frictional resistance to the reverse roller 16. For this reason, the paper feed unit 11 needs a paper feed motor with a large driving torque, and the torque limiter of the reverse roller 16 operates before the last paper P is fed, so that the paper
There is a risk of causing double feeding and dirt. However, in the paper supply unit 11 of the present embodiment, the original P pulled out by the pull-out roller 17 and the driven roller 17a returns to FIG. 2 and the guide plate 18 slides from the nip portion of the paper supply belt 15 and the reverse roller 16. Since the document P is guided straight and pulled out in the direction in which the surface 18a extends, the wrapping angle of the document P around the pull-out roller 17 can be set to a small angle θ2 substantially equal to that of the nip portion. Friction resistance can be reduced.

As described above, in the present embodiment, the reverse roller 16 and the like can be rotationally driven by the feed motor having a small driving torque, and the torque limiter works before the last document P is fed, so that the reverse roller 16 is driven. Can be prevented from being reversely rotated by the driven rotation. Therefore, it is possible to reduce the cost by using a small-torque driving motor as the paper feeding motor, and to prevent the reverse roller 16 from being inadvertently driven and rotated to cause the double feeding or the dirt on the document P. .

In this embodiment, an example of the guide plate 18 in which the end of the sliding contact surface 18a has an edge shape is shown.
The document P is not limited to this shape. For example, it is needless to say that the document P may be formed in a curved shape so as not to cause streaks or breakage, and its surface may be formed smoothly. Next, FIG. 4 is a diagram illustrating a second embodiment of the document feeder according to the present invention, and is a diagram illustrating an example mounted on an image reading device that reads an image from a document. This embodiment corresponds to the first and third aspects of the present invention, and has substantially the same configuration as the above-described embodiment. Therefore, the same components are denoted by the same reference numerals and the characteristic portions will be described. .

In FIG. 4, a paper feeding unit 11 includes a paper feeding belt 15
In addition, a guide roller 19 having an outer peripheral top surface located in a direction substantially perpendicular to the direction in which the document P is sandwiched, is provided on a guide plate 19 used in the related art provided between the nip portion of the reverse roller 16 and the pull-out roller 17. The guide roller 20 is rotatably supported. The guide roller 20 holds the lower surface of the document P, which is pulled out of the nip portion between the feed belt 15 and the reverse roller 16 by the pull-out roller 17 and the driven roller 17a, by the feed belt. Guide straight from the nip by 15 and reverse roller 16.

Therefore, in the paper feeding section 11 of the present embodiment, similarly, the original P pulled out from the nip portion of the paper feeding belt 15 and the reverse roller 16 while being held between the pull-out roller 17 and the driven roller 17a is wound around the reverse roller 16. The angle can be set to a small angle θ2 approximately equal to the nip portion,
Friction resistance caused by winding around the reverse roller 16 can be reduced.

As described above, also in the present embodiment, it is possible to obtain the same operation and effect as in the above-described embodiment. Further, the pull-out roller 17 and the driven roller 17a pull out the document P held by the paper feed belt 15 and the reverse roller 16 at the nip portion against the frictional resistance with the reverse roller 16 rotating clockwise and feed the sheet downstream. Therefore, tension (smaller than that in the prior art) is applied to the document P. For this reason, in the guide plate 18 in the above-described embodiment, since the guide plate 18 slides on the slide contact surface 18a in a state where the tension is applied,
When the guide plate 18 has a flaw, for example, the document P may be streaked (scratched), or when the document P stops halfway due to an error or the like, the document P may be broken. However, in the present embodiment, since the guide is provided by the rotatable guide roller 20, there is no possibility that the document P is damaged, and the above-described effects can be obtained.

[0024]

According to the present invention, the original to be held between the separation member and the nip portion of the sheet feeding member in order to separate the sheets one by one,
Since the area of sliding contact with the separating member is small and guided downward by the sliding contact surface of the guide member or the guide roller and sent out downward, the original and the separating member are slid only in a small area of about the nip portion. As a result, the frictional contact with the document, which is a load on the separation member due to the sliding contact, can be reduced. Therefore, the separation member can be driven by the drive motor having a small torque, which can contribute to cost reduction. In addition, by reducing the load on the separating member, it is possible to prevent the separating member from being inadvertently rotated by frictional resistance caused by a member other than the last document even though an unfed original remains. As a result, it is possible to prevent double feeding and dirt of a document, thereby improving reliability.

Further, when a document sandwiched between the nip portion of the separation member and the sheet feeding member is guided by a guide roller that can be driven and rotated, the sliding contact with the lower surface of the document can be reduced and the document can be guided. The reliability can be further improved by eliminating the possibility of damage such as sticking or breaking.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a document feeder according to the present invention, and is a transparent front view showing an example mounted on an image reading apparatus.

FIG. 2 is an enlarged front view showing a main part thereof.

FIG. 3 is an enlarged front view showing a main part in the prior art.

FIG. 4 is a diagram illustrating a second embodiment of the document feeder according to the present invention, and is an enlarged front view illustrating a main part thereof.

[Explanation of symbols]

 10 Document feeder 11 Paper feed section 12 Document table 14 Recall roller (recall means) 15 Feed belt (separation means) 16 Reverse roller (separation means) 17 Pull-out roller (feed means) 18 Guide plate (guide means, guide) 18a Sliding contact surface 20 Guide roller (guide means) 21 Transport unit 31 Paper discharge unit 41 Paper discharge tray 42 Paper discharge table C Contact glass (processing position) H Machine body

Claims (3)

[Claims] An original table on which a bundle of plural originals can be set, a calling means for calling the original bundle on the original table to a downstream side, and originals separated from the called original bundle by a nip portion one by one. A document feeder, comprising: a separating unit that nips and sends the document downstream; and a sheet feeding unit that feeds the separated document to a position below the separating unit. A separating member for preventing the document fed from the sheet feeding means from being fed to the sheet feeding means by driving the sheet in a direction opposite to the sheet feeding direction while sliding against the sheet feeding means. A document feeder provided with guide means for guiding the document so as to be pulled straight out of the nip portion. 2. The guide means comprises a guide member extending in a direction substantially perpendicular to the direction of nipping the document at the nip by the separating means and having a sliding contact surface for guiding the lower surface of the document. The document feeder according to claim 1, wherein: 3. The guide means is formed by a driven rotatable guide roller whose outer peripheral top surface is located in a direction substantially perpendicular to a direction in which the document is nipped at the nip by the separating means and guides the lower surface of the document. The document feeder according to claim 1, wherein the document feeder is configured.