JPH0859018A - Automatic document carrying device - Google Patents

Abstract

PURPOSE: To provide an automatic document carrying device which embodies the miniaturization and weight reduction of a document carrying section, and prevents the contamination resulting from the friction of the document, and facilitates an escape for a backfeed portion being due to switch back for removing the reading error in a reading section. CONSTITUTION: An automatic document carrying device has a separation means for separating documents loaded in a hopper 4 one sheet by one sheet by a pickup roller 6 and a frictional separating pad 7; and a pair of upstream driving rollers 14, 15 for supply-feeding the documents separated by the separation means to an image reading position P. A following roller 10 for guiding the documents carried sandwichedly by the separation means and a pair of upstream driving rollers 14, 15 so as to make bending is arranged in a document carrying route.

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 which is attached to an image reading device such as a copying machine and guides documents one by one to an image reading position.

[0002]

2. Description of the Related Art Generally, an automatic document feeder provided in the above image reading apparatus separates an original from a stacker on which the originals are stacked by a separating means, and a scanner separates the separated originals. It is configured to be conveyed to the arranged reading unit. The path from the separating means to the reading unit is, for example, Japanese Patent Laid-Open No. 3-186540, Shokai 6
As disclosed in Japanese Patent No. 3-40059, there is arranged a conveying roller means constituted by a driving roller and a pinch roller abutting on the driving roller, or a paper guide.

In this case, if the path from the separating means to the reading section is curved, and a curved paper guide is arranged in this portion, the document sandwiched by the conveying roller of the reading section and the separating means. However, the document surface is strongly rubbed by the paper guide as the paper is transported. Particularly, in the case of a two-sided manuscript, a newspaper, a magazine, etc. written with a pencil, the description is damaged by friction. Therefore, by disposing the transport roller means in the middle of the curved transport path, the document is not strongly rubbed, and the document can be prevented from being soiled due to friction.

However, by disposing the conveying roller means in the conveying path, a driving force transmitting means or the like is required, which causes a problem that the structure becomes complicated and the weight becomes high and the cost becomes high. Furthermore, in the case where the reading unit scans the document while switching it back, there is a problem that slipping is likely to occur when the document is back-fed if the document quality is hard. That is, since the rear side of the document is pinched by the pinching part of the transport roller means, it is difficult for the document to be back-fed to bend, and slippage occurs at the drive roller arranged in the reading part. Read errors will occur.

The present invention aims to reduce the size and weight of the document transport section and prevent the document from being soiled due to friction, and to facilitate the escape of the back feed due to the switchback to eliminate reading errors in the reading section. An object of the present invention is to provide a document feeder.

[0006]

In order to solve the above-mentioned problems, an automatic document feeder attached to an image reading apparatus of the present invention has a hopper for stacking and stacking documents and a document placed on this hopper. Separation means for separating the sheets one by one, upstream conveyance roller means for feeding the originals separated by the separation means to the image reading section, and downstream conveyance roller means for conveying the originals on which the images have been read toward the discharge stacker. And a guide means for guiding the original that is nipped and conveyed by the separating means and the upstream conveying roller means so as to be curved. The guide means is a driven roller that forms a vertex of the curve on the original. It is characterized by being.

[0007]

A guide for guiding an original between a separating means for separating the originals placed on the hopper one by one and an upstream conveying roller means for feeding the originals separated by the separating means to the image reading section. A driven roller is provided as a member. When the original is conveyed, the driven roller rotates with the conveyance of the original, so that the friction acting on the original is reduced and the original is prevented from being soiled. Further, when the document is back-fed, the document can be easily bent and escaped at the position where the driven roller is arranged, that is, the position of the apex of the curve of the document, and the document is arranged on the upstream side of the image reading unit. There is no slippage at the drive roller pair.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of an automatic document feeder according to the present invention. The automatic document feeder 1 is attached to the image reading device 100, and is rotatable about the support shaft 2 on the contact glass 101 in the arrow direction. In the automatic document feeder 1,
A detachable hopper 4 is attached, and the documents D are stacked and placed on the pressing plate 5 of the hopper 4. The document D is picked up by the pickup roller 6 against which the document D is abutted by the biasing spring.
And a friction separating pad 7 urged to the outer peripheral surface of the pickup roller to separate the pickup roller into one sheet. The original separated into one sheet via the drive of the pickup roller 6 and the friction separation pad 7 is guided by the ribs 9 and 12 arranged on the downstream side of the hopper 4 and conveyed to the upstream drive roller pair 14 and 15. . Then, the document is fed to the image reading position P of the image reading apparatus 100 by the upstream drive roller pair 14 and 15.

The separating means and the upstream drive roller pair 14, 1
The conveying path between the sheet and the sheet 5 is curved for downsizing of the apparatus, and the driven roller 10 is arranged in this conveying path. The original document is conveyed along the curved conveyance path, and the apex of the curve is formed at the driven roller 10, and the original document is conveyed so as to slide on the outer peripheral surface. That is, the driven roller 10 forms a curved vertex on the document when the front and rear ends of the document are nipped and conveyed. The position of the driven roller 10 is not limited to the position shown in the figure, and may be a position facing the rib 12, for example. In this case, the apex of the curve is formed at this portion in the conveyed document.

A window frame body 20 is detachably attached to the lower surface of the automatic document feeder 1, and the window frame body 20 corresponds to the image reading position P of the image reading apparatus 100. Windows are formed. In addition, the window frame body 20
An upstream guide 22 which is inclined forward so as to guide the document to this window, and inclined backward so as to guide the document scanned by the reading head 102 to the downstream drive roller pair 48, 50. The downstream guide 25 is formed. A transparent film 30 made of, for example, polyester is attached to the window frame body 20 configured as described above so as to cover the guide members 22 and 25 and the window portion.
The transparent film 30 feeds the document conveyed by the upstream drive roller pair 14 and 15 to the image reading position P between the transparent film 30 and the pressing plate 45 without causing a jam, and reads the image. The leading edge of the document thus picked up is reliably picked up and guided to the downstream drive roller pair 48, 50.
A paper discharge roller 55 is arranged on the downstream side of the downstream drive roller pair 48, 50, and the read original is stored in the stacker 5
7 is ejected.

Next, the operation of the above embodiment will be described with reference to FIGS. The originals stacked on the hopper 4 are driven by the pickup roller 6 and the friction separation pad 7
It is separated into one by. The manuscript separated into one is
It is conveyed downward along the curved path along the rib 9 and is guided to the upstream drive roller pair 14 and 15 via the rib 12. During this period, the document is guided mainly by the ribs 9 and 12 at the leading end thereof, and the driven roller 10 is slightly rotated as the document moves (see FIG. 2).

When the document is nipped by the upstream drive roller pair 14 and 15, the drive of the pickup roller 6 is stopped, and the document is conveyed by the drive of the upstream drive roller pair. At this time, the pickup roller 6 rotates together with the document conveying operation. Further, the rear end side of the document in the conveyed state receives a slight resistance at the pressure contact portion between the pickup roller 6 and the friction separation pad 7, and becomes a tensioned state as shown in FIG. Therefore, a curved apex is formed on the original at the driven roller 10, and the original is conveyed while pulling around the driven roller 10 without making any contact with other members (ribs 9 and 12). In this case, if the driven roller 10 is composed of a guide plate or the like, the document is contaminated due to the friction generated by the document transport operation. Since it rotates, the original is not contaminated.

When the image reading operation at the image reading position P is started, the original is placed on the upstream drive roller pair 14, 15.
It is transported while being switched back by. FIG.
Shows the state of the document when it is switched back. When the upstream drive roller pair 14 and 15 are reversely rotated and back fed by a predetermined amount, the document is easily bent and escapes in the driven roller 10. it can. That is, since slippage or the like does not occur at the position of the upstream drive roller pair 14, 15, it is possible to prevent reading mistakes.

As described above, since the driven roller as the guide means is arranged in the path for conveying the original, it is not necessary to provide a pair of driving rollers for conveying the original, and the size is small.
The weight can be reduced. In this case, the driven roller 10
The configuration may be configured as shown in FIG. 5, for example. That is, the driven roller is usually formed in a cylindrical shape, but in this modification, a plurality of disk-shaped members 10a are arranged at appropriate intervals and are fixed to the support shaft 10b. According to this structure, the driven roller 10 can be further reduced in weight, and the driven roller 10 can be driven more easily. As a result, the friction generated on the document surface is reduced, the contact area with the document surface is reduced, and it is possible to further prevent the document from being soiled.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be variously modified. For example, the configuration of the separating means for separating the original into one sheet, the conveying path of the original, and the like can be appropriately modified. Further, a plurality of driven rollers may be arranged in the curved sheet conveying path. In this case, curved apexes are formed on the document at all the driven rollers or at any one of the driven rollers. Further, the driven roller may have a structure other than that shown in FIG. 5, for example, a roller divided into a plurality of parts in the axial direction.

[0016]

As described above, according to the automatic document feeder of the present invention, it is not necessary to provide a drive roller pair or the like for document feeding, and the overall size and weight can be reduced. Further, the rotation of the driven roller prevents the original document from being damaged due to friction. Further, the escape of the back feed due to the switchback is secured, and the reading error in the reading unit is eliminated.

[Brief description of drawings]

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

FIG. 2 is a view showing a state where the original is separated into one sheet in the automatic original feeding apparatus shown in FIG.

FIG. 3 is a diagram showing a state in which a document is further conveyed from the state shown in FIG.

FIG. 4 is a diagram showing a state in which a switchback is performed in a document reading operation.

5 is a diagram showing a modified example of a driven roller in the automatic document feeder shown in FIG.

[Explanation of Codes] 1 ... Automatic document feeder, 6 ... Pickup roller, 7 ...
Friction separating pad, 9 ... Rib, 10 ... Driven roller, 12 ...
Ribs, 14, 15 ... upstream drive roller pair, 20 ... window frame,
30 ... Transparent film, 48, 50 ... Downstream drive roller pair,
100 ... Image reading device, 101 ... Contact glass, 1
02 ... Read head.

Claims (2)

[Claims] 1. An automatic document feeder attached to an image reading apparatus, comprising: a hopper for stacking documents, a separating unit for separating the documents placed on the hopper one by one, and the separating unit. In the automatic document feeder, the upstream document feeding roller unit feeds the separated document to the image reading unit, and the downstream document transport roller unit conveys the document whose image has been read toward the paper output stacker. And an upstream conveyance roller means, the guide means is provided to guide the original to be bent and conveyed, and the guide means is a driven roller that forms a vertex of the curve on the original. Document feeder. 2. The automatic document feeder according to claim 1, wherein the driven roller is composed of a plurality of disk-shaped members arranged at predetermined intervals in the axial direction.