JPH0792578A - Original carrying device - Google Patents

Abstract

PURPOSE:To take effect that image blurring, scratch in a copying feasible image area part and the stain of an original glass are not caused. CONSTITUTION:Assuming that a distance from the leading edge of a carrier sheet 1 to the leading edge of the copying-feasible image area is L1, a distance from the trailing edge of the copying-feasible image area to the trailing edge of the carrier sheet 1 is L2, a distance from a nip position 14 by an original ejecting roller to the position 12 of an image exposure part is L3, and a distance from the position 12 to a nip position 15 by a paper supply roller is L4; a condition L1>L3 and L2 L4 is satisfied so that the position of the image exposure part in the vertical direction is not changed from the time when the leading edge of the original rushes in the image exposure part till the time when the trailing edge of the original passes through the image exposure part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder such as a copying machine, a printer, a facsimile, etc. for passing a document through an image exposure position.

[0002]

2. Description of the Related Art Conventionally, a document feeding device uses a document holding device for sandwiching and holding a document by a sheet-shaped member, that is, a so-called carrier sheet, and the carrier sheet passes through an image exposure device. , To read a manuscript. The carrier sheet is conveyed by a document feeding roller and a document ejecting roller, and the conveying speeds of the sheet feeding and ejecting rollers are set to be the same.

Further, there is a document glass between the document feed roller and the document discharge roller, an upper part thereof holds the document down, and a lower part thereof has an illumination system for irradiating light from below the document glass. An optical system and an optical information receiving means, for example, a photoconductor for electrophotography in a copying machine or a facsimile or the like, is composed of a CCD element or the like.

[0004]

By the way, in such a document feeder, the document feeding roller and the document discharging roller are set to have the same feeding speed as described above. Even if it was set, it was extremely difficult to make the transportation speed of the transportation roller the same because of variations in accuracy of parts.

When the tip of the carrier sheet rushes into the document discharge roller nip, a force acts on the carrier sheet in the vertical direction, and the carrier sheet moves away from the document glass, causing image blurring. . Further, image blurring occurs due to a shock when the trailing edge of the carrier sheet passes through the original feeding rubber roller.

Since the copyable image area of the carrier sheet and the original glass are in contact with each other, the copyable image area is scratched or the original glass is contaminated. There is also a problem that reading failure occurs and information is lost.

In order to solve the above-mentioned problems, the object of the present invention is to change the vertical position of the image exposing portion from the time when the leading edge of the original enters the image exposing area until the trailing edge of the original passes through the image exposing area. An object of the present invention is to provide a document feeder that is free from image blurring, scratches in the copyable image area, and stains on the document glass.

[0008]

In order to achieve the above-mentioned object, the present invention is a conveyance roller arranged along a conveyance path of the sheet-shaped member with the front and back sides of the original document sandwiched by the sheet-shaped member. -The sheet-shaped member is clamped by a plurality of pairs of transport rollers that are different so that the transport speed on the downstream side of the roller is fast and the nip position of the transport roller is higher than the image exposure position. In the document conveying apparatus for conveying, the distance from the front end of the sheet-shaped member to the front end of the copyable image area is L1, and the distance from the rear end of the copyable image area to the rear end of the sheet-shaped member is L2. L3 is the distance from the document discharge roller nip position to the image exposure unit, and L4 is the distance from the image exposure unit to the document feed roller nip position. L1> L3 and L
The document feeder is characterized by satisfying the condition of 2> L4.

[0009]

By using the document feeder of the present invention,
The distance from the leading edge of the sheet-shaped member to the leading edge of the copyable image area is L1, and the distance from the trailing edge of the copyable image area to the trailing edge of the sheet-shaped member is L2. The distance from the position to the image exposure unit is L3, and the distance from the image exposure unit to the document feeding roller nip position is L4.
By satisfying the conditions of 1> L3 and L2> L4, the position of the image exposure part in the vertical direction changes from the leading edge of the document entering the image exposure part until the trailing edge of the document leaves the image exposure part. There is no image blurring, no scratches on the copyable image area, and no stain on the original glass.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a top perspective view of the document holding device implemented in FIG. 1, and FIG.
Shows a document holding state diagram of the document holding device. 1 to 3, a document holding device, a carrier sheet in this embodiment.
To 1 is a transparent material such as polyethylene terephthalate
Overlace made of plastic film such as
The sheet 2 and the base sheet 3 are heat-welded or bonded at the joint portion 1a.

The carrier sheet 1 has an original surface of an original D which is placed between an overlay sheet 2 and a base sheet 3.
Insert the original D towards the sheet 2
L is the copyable image area.

When the document sheet is read by the document reading device, if the carrier sheet 1 holding the document sheet D is placed on the paper feed tray 10, the joint portion 1a becomes the downstream side, and the healthy sheet is fed while sliding down. The sensor arrives at a sensor (not shown) in the vicinity of the transport roller 4, and the drive is transmitted from the main motor (not shown) to the drive roller 4a of the document feed transport roller 4 to drive the driven roller. Paper feeding is started between 9 and 9.

The carrier sheet 1 passes between the document glass 6 and the document retainer 7 and is transported to the document discharge transport roller 5 side. Here, the conveyance speed of the document discharge roller 5 is made different from the conveyance speed of the document feed roller 4.

The document retainer 7 is arranged so as to be movable in the circumferential direction around the support shaft 7a. Also, the document holder 7
The resin spring 7b arranged at is configured to be pressed from above by the upper cover 8. Therefore, even when the thick document D is loaded, the gap between the document glass 6 and the document retainer 7 can be secured.

When the leading edge of the copyable image area L of the carrier sheet 1 reaches the image exposure position 12 as the conveyance advances, image exposure is started and the trailing edge of the copyable image area L is located at the image exposure position. It continues until the sheet exits 12 and is finally discharged to the sheet discharge tray 11.

At this time, the distance from the front end of the copyable image area L to the front end of the carrier sheet 1 is L1, and the distance from the rear end of the copyable image area L to the rear end of the carrier sheet 1 is L2.
, Document exposure roller nip position 14 to image exposure position 1
Let L3 be the distance to 2 and L4 be the distance from the image exposure position 12 to the document feeding roller nip position 15
The condition (1) is satisfied.

L1> L3, L2> L4 (1) Therefore, when the copyable image area L passes through the image exposure position 12, the carrier sheet 1 is always in the original sheet discharge roller 5. Is adjusted to a position higher than the image exposure position 12 (position where the focus of the document D floats), and is conveyed in balance in a vertical position where the document glass 6 is not contacted. Since there is no change in, the image blur does not occur. Therefore, neither scratches on the copyable image area L of the carrier sheet 1 nor stains on the original glass 6 occur.

The present invention is not limited to the above embodiments, but can be implemented in other modes by making appropriate design changes.

[0020]

As is apparent from the above description, in the document feeder of the present invention, the distance from the tip of the sheet-shaped member to the tip of the copyable image area is L1, and the copyable image area is set. The distance from the rear end to the rear end of the sheet-shaped member is L2,
The distance from the document discharge roller nip position to the image exposure unit is L3, and the distance from the image exposure unit to the document feed roller nip position is L4, and the conditions of L1> L3 and L2> L4 are satisfied. This effectively solves the problems of the prior art, and the image exposure portion position in the vertical direction does not change until the trailing edge of the original document passes through the image exposure portion after the leading edge of the document enters the image exposure portion. This has the effect of preventing blurring, scratches in the copyable image area, and stains on the original glass.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

2 is a top perspective view of the document holding device implemented in FIG. 1. FIG.

FIG. 3 is a document holding state diagram of a document holding device.

[Explanation of symbols]

 1 Carrier Sheet 4 Original Feeding Roller 5 Original Ejecting Roller 6 Original Glass 7 Original Presser 12 Image Exposure Position

Claims (1)

[Claims] 1. A sheet-shaped member is sandwiched between the front and back sides of an original so that the conveying speed on the downstream side of a conveying roller arranged along the conveying path of the sheet-shaped member is made different so as to be faster. Further, in a document conveying device which holds and conveys the sheet-shaped member by a plurality of pairs of conveyance rollers whose nip position of the conveyance roller is higher than the image exposure position, from the tip of the sheet-shaped member. The distance from the end of the copyable image area to L1 and the distance from the rear end of the copyable image area to the rear end of the sheet-shaped member are L2, and the distance from the original discharge roller nip position to the image exposure unit. Is L3, and the distance from the image exposure unit to the original feeding roller nip position is L4, and L1> L3 and L
A document feeder which satisfies the condition of 2> L4.