JP3537557B2 - Automatic document feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder mounted on an image forming apparatus, and more particularly, to a method of separating documents one by one from a plurality of document bundles and transporting them to an image reading means stopped at a reading position. And an automatic document feeder.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or the like, when a document bundle composed of a plurality of documents is placed on a document table and copying is instructed, the documents are separated and read one by one. When the reading of the original is completed by the image reading means which conveys the original to the position and stops at the reading position, there is an automatic document feeder which discharges the original to a predetermined discharge position. As a document feeder, for example, one described in Japanese Utility Model Laid-Open Publication No. 3-85377 is known.

[0003] This document comprises a document table on which a document composed of a plurality of documents is placed, a separation sheet feeding means for separating and feeding the document placed on the document table, and a separation sheet feeding means. Two slit glasses arranged along the downstream of the document transport direction, first and second transport drums respectively provided on the two slit glasses, and a document switch provided between the transport drums. A switchback means for backing and transporting the document to the second transport drum, and a document discharge table provided downstream of the second transport drum in the document transport direction are provided.

In the automatic document feeder having such a configuration, when a single-sided document is transported, the document separated by the separating sheet feeding means is transported to the second transport drum through the first transport drum, and the second transport drum is transported. After the image is read by the image reading means through the slit glass below the drum, the image is discharged to the document discharge tray. When the double-sided document is transported, the surface of the document separated by the separation paper feeding means is passed through the slit glass below the first transport drum. After the image is read by the image reading unit, the document surface is reversed by switching back by the switchback unit, the back surface of the document is read by the reading unit through the slit glass below the second transport drum, and then discharged to the document discharge table. It is designed to be paper.

[0005]

However, such a conventional automatic document feeder has two slit glasses and a transfer drum, and a switchback means provided between the slit glasses. Then, when the double-sided document is transported, the front surface of the document is read through the slit glass below the first transport drum, then inverted by the switchback means, and then the back surface of the slit glass under the second transport drum is read. As a result, the document conveyance path is very long and the structure is complicated. For this reason, there has been a problem that the size and weight of the automatic transfer device are increased, and the manufacturing cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-cost automatic document feeder capable of shortening the length of a double-sided document transfer path and simplifying the structure, thereby reducing the size and weight. You.

[0007]

According to the first aspect of the present invention,
In order to solve the above-mentioned problems, in an automatic document feeder configured to read a document by an image reading unit while transporting the document to a reading position, an automatic document feeder includes a document table on which a document bundle including a plurality of documents is placed. The document from the document table.
Separating the originals one by one
Separating / transporting means for transporting the document conveyed to the reading position through the transport path, and a forward / reverse rotatable discharge mechanism for discharging the document conveyed through the second transport path onto the document discharge table after reading at the reading position is completed. Paper means, a switchback path communicating the downstream side of the second conveyance path in the document conveyance direction with a predetermined location of the first conveyance path, a first communication position communicating the paper discharge means with the second conveyance path, and Switching means capable of communicating with a second communication position that communicates the paper discharge means with the switchback path; and when the switching means is switched to the second communication position,
The paper discharge means communicates with the first transport path via the switchback path, and connects the paper discharge means to a driving member and a front side.
When it is composed of a driven member that can contact and separate from the driving member,
In both cases, the front end and rear end of the same original
When the driving member and the driven member overlap,
The material is separated from the driving member .

In this case, when the switching means is switched to the second communication position, the paper discharge means is connected to the first conveyance path via the switchback path.
When reading the back side of the document whose front side has been read, the document is returned to the reading position via the switchback path, and the document is conveyed in a loop. For this reason, the document conveyance path is shortened and the structure is simplified, and the size and weight of the automatic document conveyance device are reduced.
It will be cheap.

[0009]

[0010] Further , the front end side and the rear end of the same original in the conveying direction.
When the end side overlaps between the driving member and the driven member,
Since separating the member from the drive member, without the front and rear end side rubbing the originals, it is never soiled document. Also,
Because the transport load is reduced, the transport speed of the document is stable,
Image reading accuracy is improved. The distance between the drive member and the driven member when the drive member is separated is preferably set to about 1 mm or more, which is a distance corresponding to the length of two originals.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment of the automatic document feeder according to the present invention, in which the automatic document feeder is mounted on an image forming apparatus such as a copying machine.

First, the configuration will be described. 1 and 2, reference numeral 1 denotes a copying machine as an image forming apparatus. On the top surface of the copying machine 1, a slit glass (reading position) 2 and a contact glass 3 are provided. This slit glass 2
An exposure lamp 4 and a first mirror 5 serving as image reading means are provided below the contact glass 3. The lamp 4 and the first mirror 5 are used when reading an original placed on the contact glass 3. 1 moves left and right below the contact glass 3 in FIG. 1 and stops reading below the slit glass 2 when reading the original on the slit glass 2, and after exposing the original surface by the exposure lamp 4, The reflected light is imaged on a CCD via a first mirror 5 and a lens (not shown) as is well known.

An automatic document feeder (hereinafter, simply referred to as an ADF) 6 is mounted on the upper part of the copying machine 1, and a document placed on the contact glass 3 is placed on the lower surface of the ADF 6 on the contact glass 3. A reflection plate 7 that is pressed and serves as a white reference when reading a document is provided. Also,
A document placing table 8 is provided on the upper part of the ADF 6, and a document bundle P including a plurality of documents is placed on the placing table 8. An original bundle P placed on the original placing table 8 is a call roller 9 that can contact and separate from the original bundle P.
After the paper is fed, the paper is separated by a separation roller pair 10. The separation roller pair 10 rotates clockwise, and separates the uppermost document from the document bundle P.

The separated document is a pull-out roller pair 11
The sheet is conveyed along a first conveying path 13 by a pair of conveying rollers 12, and the first conveying path 13 constitutes a conveying path for inverting the original and conveying the original to the slit glass 2. In the present embodiment, the above-described call roller 9 and separation roller pair
The pull-out roller pair 11 and the transport roller pair 12 constitute a separating / transporting unit, and are driven by a paper feed motor 51. The lower roller 10a of the separation roller pair 10 is connected to a paper feed clutch 55, and the paper feed clutch 55 is driven based on a signal from the controller 50, and when the preceding document is separated, The roller 10a idles with respect to the separated document without transmitting the driving force of the paper feed motor 51 to the roller 10a.

A document set sensor 14 is provided on the document table 8, and the sensor 14 detects the presence or absence of a document on the document table 8 and outputs a signal to the controller 50. I have. A document separation sensor 15 is provided between the separation roller pair 10 and the pullout roller pair 11, and the sensor 15 detects that the document has been separated and outputs a signal to the controller 50. When this signal is input, the controller 50 controls the paper feed clutch 55 as described above so that the driving force of the paper feed motor 51 is not transmitted to the roller 10a.

A transport roller pair 16 is provided downstream of the slit glass 2 in the document transport direction.
16 is driven by a paper feed motor 51 and the slit glass 2
The document which has been read in step (1) is conveyed to a pair of discharge rollers (discharge means) 18 via a second conveyance path 17. The sheet discharge roller pair 18 includes a drive roller (drive member) 18a and a driven roller (driven member) 18b. The drive roller 18a is disposed on the copying machine 1 side, and is rotated forward and reverse by a sheet discharge motor 53. It has become so.

The paper discharge roller pair 18 holds the document that has been read on the slit glass 2 and holds the document table 8.
The document is discharged to a document discharge table 19 provided at the lower part. The driven roller 18b is configured to be brought into contact with and separated from the driving roller 18a by the solenoid 52. When the driven roller 18b is separated from the driving roller 18a, the driven roller 18b is separated from the driving roller 18a by about 1 mm as shown in FIG. The gap δ described above (corresponding to the thickness of about two originals) is formed. The solenoid 52 is driven by a signal from the controller 50.

On the other hand, on the downstream side of the discharge roller pair 18 in the document transport direction, the downstream side of the second transport path 17 in the document transport direction and the first transport path 13
A switchback path 20 communicating with a predetermined location is provided, and a switching claw 21 as switching means is provided on the upstream side of the discharge roller pair 18 in the document conveying direction. The switching claw 21 is connected to a first communication position (indicated by a solid line in FIG. 1) where the discharge roller pair 18 and the second conveyance path 17 communicate with each other by a switching solenoid 54 controlled by a controller 50, and the discharge roller pair 18 and a switch. The position can be switched to a second communication position (indicated by a broken line in FIG. 1) that communicates with the back path 20, and varies the document conveyance path.

The first transport path 13 has a registration sensor
The sensor 22 detects the front end of the document and outputs a signal to the controller 50. A discharge sensor 23 is provided upstream of the discharge roller pair 18 in the document transport direction.
Is designed to detect the front and rear ends of the document and output a signal to the controller 50.

A controller 50 drives a paper feed motor 51 and a paper feed clutch 55 based on the document set sensor 14 and the document separation sensor 15, and a registration sensor.
The solenoid 52, the sheet discharge motor 53, and the switching solenoid 54 are controlled based on detection signals from the sheet discharge sensor 22 and the sheet discharge sensor 23 as described later. In FIG. 1, 24
Is a scale that scoops up the document that has passed through the slit and the glass 2 and conveys it to the second conveyance path 17.

Next, the operation of conveying a two-sided original will be described. First, when a document bundle P composed of a plurality of double-sided documents is placed on the document table 8, the document set sensor 14 detects that a document is placed and outputs a signal to the controller 50. Then, when the copy start switch provided on the operation panel of the copying machine 1 is pressed, the controller 50 drives the separation / feeding means by the feed motor 51 in response to the operation signals of the set sensor 14 and the copy start switch.

That is, after the original bundle P is fed by the calling roller 9 in contact with the original bundle P, the separation roller pair 10
, And then transported along the first transport path 13 by the pull-out roller pair 11 and the transport roller pair 12. When the separation sensor 15 detects the front end of the document P1, the paper feed clutch 55 prevents the roller 10a from running idle and the subsequent document from being separated.

Next, when the front end of the document P1 is detected by the registration sensor 22, the controller 50 drives the exposure lamp 4 based on this signal to read the surface of the document P1 and to drive the paper discharge motor 53. The driving roller 18a is driven to rotate forward in the clockwise direction. Next, the read original P1 is transported by the transport roller pair 16 through the second transport path 17 toward the paper discharge roller pair 18. At this time, the switching claw 21 is at the position indicated by the solid line in FIG. since located 1 communication position, the document P1 surface of the reading is finished the sheet discharge roller pair 18
And transported (see FIG. 4).

Next, the trailing end of the document P1 is
3 is detected by the controller 50, the controller 50
After the operation of 3 is temporarily stopped, after the switching claw 21 is switched to the second communication position indicated by the one-dot chain line by the switching solenoid 54,
The discharge motor 53 is driven to rotate in the counterclockwise direction. For this reason, the original P1 whose rear end is sandwiched by the discharge roller pair 18
Is transported to the first transport path 13 through the switchback path 20 (see FIG. 5).

At this time, when the front end of the document P1 is detected by the registration sensor 22, the controller 50 temporarily stops the operation of the sheet feeding motor 51 and switches the switching solenoid 54 to the first communication position. Next, the paper feed motor 51
Is driven to restart the conveyance of the document P1, and then the exposure lamp 4
To read the back side of the document P1 and output the motor 5
3 to drive the original P1 by the discharge roller pair 18
Discharge to 19 At this time, when the trailing end of the discharged document P1 is detected by the discharge sensor 23, the paper feed clutch 55 is driven to feed the succeeding document.

On the other hand, when the switchback path 20 is short or when a long document P1 such as A4 is conveyed, the document P1 may be pinched in a state where the front and rear ends of the document P1 are overlapped by the discharge roller pair 18. is there. In this embodiment, when the original P1 is transported in such a state, as shown in FIG. 5, the original P1 whose front surface has been read is transported to the first transport path 13 via the switchback path 20, and When the front end of the document P1 is detected by the sensor 22, the controller 50 drives the solenoid 52 to separate the driven roller 18b from the driving roller 18a by δ, and temporarily stops the operation of the sheet feeding motor 51. The switching solenoid 54 is switched to the first communication position. Next, the paper feed motor 51 is driven to restart the conveyance of the document P1, and the exposure lamp 4 is driven to drive the document P1.
The original P1 is conveyed by the discharge roller pair 18 by driving the discharge motor 53 by reading the back surface of the document 1.

At this time, as shown in FIG. 6, the document P1 is conveyed in a state where the front and rear ends are overlapped. Then, the original P
When the trailing end of 1 is detected by the registration sensor 22, the controller 50 drives the solenoid 52 to drive the driven roller.
The original P1 is discharged by bringing the original 18b into contact with the driving roller 18a via the original P1. In this embodiment, when the conveyance of the long document P1 such as A4 is set on the operation panel of the copying machine 1, the driven roller 18b is driven by the driving roller 18a as described above.
Alternatively, a sensor for detecting the length of the document may be provided on the document table 8 and the control for separating the driven roller 18b from the driving roller 18a may be performed based on the sensor information. When the switchback passage 20 is short, control for separating the driven roller 18b from the driving roller 18a may be always performed.

As described above, in this embodiment, the switching claw 21 is
When switched to the communication position, the paper discharge roller pair 18 communicates with the first transport path 13 via the switchback path 20, and when the double-sided document is transported, the original whose front side has been finished is transferred to the switchback path 20 and the first transport path 13. The document can be conveyed in a loop because the document is returned to the slit glass 2 through the slit. For this reason, the transport path of the document can be shortened, and the structure can be simplified, the size and weight of the ADF 6 can be reduced, and the ADF 6 can be manufactured at low cost.

A driving roller 18a is provided on the copying machine 1 side.
Since the driven roller 18b is disposed at a position avoiding this position, the front end and the rear end of the original in the document conveying direction are set to the discharge roller pair 18.
When the document is conveyed in the order of the switchback path 20, the first conveyance path 13, and the second conveyance path 17 in an overlapping state, the front end side of the document can always be brought into sliding contact with the driving roller 18a, The document can be smoothly conveyed and discharged to the document discharge table 19 by the driving roller 18a. Further, even if the switchback path 20 is short, the document can be smoothly discharged, so that the document transport path can be further shortened, and the ADF 6 can be further reduced in size and weight.

Further, the driven roller 18b is provided so as to be able to contact and separate from the driving roller 18a, and the gap δ between the driving roller 18a and the driven roller 18b is set to 1 mm at the time of separation. When the front and rear ends of the original in the conveyance direction are conveyed by the discharge roller pair 18 when the original is conveyed or a long document is conveyed, if the driven roller 18b is separated from the driving roller 18a, the front and rear ends of the original are Rubbing can be prevented, and the original can be prevented from becoming dirty.
Further, since the transport load can be reduced, the transport speed of the document can be stabilized, and the reading accuracy of the image can be improved.

[0031]

According to the first aspect of the present invention, when a double-sided original is conveyed, the original is returned to the reading position via the switchback path when reading the back side of the original whose front side has been read. Can be transported in a loop. For this reason, the transport path of the document can be shortened, and the structure can be simplified. As a result, the automatic document feeder can be reduced in size and weight, and can be manufactured at low cost.

[0032]

Further, when the front and rear ends of the original in the conveying direction are sandwiched by the sheet discharging means and overlap when the same original is conveyed, if the driven member is separated from the driving member, the front and rear ends of the original can be rubbed. The document can be prevented from being stained. Further, since the transport load can be reduced, the transport speed of the document can be stabilized, and the reading accuracy of the image can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an automatic document feeder according to the present invention.

FIG. 2 is a block diagram of a control system according to one embodiment.

FIG. 3 shows an example in which a driven member abuts against a driving member.
It is a state at the time of separating.

FIG. 4 is a diagram illustrating a state in which a rear end portion of a document is held and stopped by a sheet discharging unit according to an embodiment;

FIG. 5 is a diagram illustrating a state in which a document according to one embodiment is returned to a first conveyance path via a switchback path.

FIG. 6 is a diagram illustrating a state in which front and rear ends of a document according to one embodiment are overlapped and clamped by a sheet discharging unit;

[Explanation of symbols]

1 Copier (image forming apparatus) 2 Slit glass (reading position) 4 Exposure lamp (image reading means) 5 First mirror (image reading means) 6 ADF (automatic document feeder) 8 Original mounting table 9 Calling roller (separation / transportation means) 10 Separating roller pair (separating / transporting means) 11 Pull-out roller pair (separation / transportation means) 12 Conveyor roller pair (separation / transportation means) 13 First transport path 17 Second transport path 18 Discharge roller pair (discharge means) 19 Document output tray 20 Switchback passage 21 Switching claw (switching means) P manuscript

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 85/00 B65H 29/58 G03G 15/00 107 G03G 21/14

Claims (1)

(57) [Claims] 1. An automatic document feeder wherein an original is read by an image reading means while the original is being transported to a reading position, wherein an original placing table on which an original bundle comprising a plurality of originals is placed; Separating / transporting means for separating the originals one by one from the mounting table and transporting the separated originals to the reading position through a first transporting path for inverting and transporting the separated originals; A forward / reverse rotatable discharge means for discharging a document conveyed through a conveyance path onto a document discharge table, and communicating a predetermined portion of the first conveyance path with a downstream side of the second conveyance path in the document conveyance direction. A switchback passage; a switching unit capable of communicating with a first communication position that communicates the paper discharge unit with the second transport path; and a second communication position that communicates the paper discharge unit with the switchback passage; Is the second connection When switched on, the communication sheet discharge means to the first conveyance path through the switch-back path, said sheet discharge means, abuts against the drive member and the drive member,
It is composed of a driven member that can be separated and
The front end and the rear end in the transport direction of the
If the members overlap, the driven member may be
ADF equipment, characterized in that to et away.