JPS61174039A - Automatic original feeding device - Google Patents

Abstract

PURPOSE:To get rid of the occurrence of a difference in conveying velocity between front and rear ends of an original in an exposure position, by removing any resistance in a separating mechanism part before the original tip reaches the exposure position. CONSTITUTION:An original on an original table 1 is delivered by a delivery roller 33 and reaches a vertical pair of paper feed roller 4 via a paper feed belt mechanism 3. After running past this paper feed roller 4, the presence of the original is detected by a detecting member 5 so that with this detecting signal, a driving source is driven and eccentric cams 35 and 48 are rotated. Therefore, the delivery roller 33 moves to an upper position while a double-feed preventing roller 43 to a lower position, respectively, thus a paper feed roller mechanism 2 becomes nonoperational. And, since pressure lying between the double-feed preventing roller 43 and a belt 42 is weekend to some extent, a separating mechanism part consisting of the said paper fed roller mechanism 2 and the paper feed belt mechanism 3 comes into a state of being nonoperational. On the other hand, the original is conveyed by a paper feed roller 5 and fed to an original mount 13 by a conveying belt 18 at the specified velocity and exposed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic document feeder, and more particularly to an automatic document feeder that can obtain a copy image of a large-sized document in synchronization with an electrophotographic copying device. It is something.

[Prior art]

Conventionally, when copying images from large-sized originals, the so-called synchronous feeding method has been adopted, in which the optical system of the electrophotographic copying device is fixed and exposure is performed while the original is being fed. This is because the document must always be kept at a constant speed as it passes through, and generally a semi-automatic document feeding method (SDF) is adopted in which documents are loaded one by one.

In order to obtain copied images from large-sized originals using the conventional method, it is necessary to insert the originals by hand each time, making the copying process very complicated. It had

Furthermore, in the automatic document feeding system, a separation mechanism is provided in the document feeding section in order to set a plurality of documents and automatically separate and feed each document one by one.

The original passes through the separation mechanism and is transported to the exposure position by a normal transport mechanism, but since the separation mechanism has resistance to the transport of the original, the original is separated by the separation mechanism. There is a difference in the conveyance speed between the time of passing the separation mechanism and the time of completion of passing through the separation mechanism.

For this reason, when the document is large in size, when the leading edge of the document reaches the exposure position, the trailing edge of the document is still located within the separation mechanism, so the trailing edge of the document comes out of the separation mechanism. This method has disadvantages in that the conveyance speed is different after the image is transferred, and the magnification of the copied image is different between the leading edge and the trailing edge of the copied image.

Furthermore, when the trailing edge of the document is removed from the separation mechanism, it is subjected to sudden displacement, which may cause significant unevenness in the copied image.

[Purpose of the invention]

The present invention eliminates the drawbacks of the conventional ones as described above, and eliminates the resistance of the separating mechanism in an automatic document feeder before the leading edge of the document reaches the exposure position.
Eliminates the difference in conveyance speed between the leading edge and trailing edge of the original at the exposure position, thereby eliminating changes in magnification and uneven alignment between the leading edge and trailing edge of the copied image. The purpose of the present invention is to provide an automatic document feeder that does not cause problems.

[Structure of the Invention] The present invention provides an automatic document feeder capable of transporting a document by a separation mechanism section and a transport section, in which a detection member is disposed in the transport section, and the detection member detects when the document is separated. The separation mechanism is configured to be inactivated when the separation mechanism is detected to have been conveyed by the conveyance unit after passing through the mechanism.

[Embodiments of the invention]

Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows a schematic diagram of an automatic document feeder according to the present invention, in which a paper feed roller mechanism 2 is provided on the upper part of the document table l, and a document fed by the paper feed roller mechanism 2 is provided. A paper feed belt mechanism 3 is provided for preventing double feeding and for conveying the paper, and the paper feed roller mechanism 2 and the paper feed belt mechanism 3 constitute a separation mechanism section.

A transport section is provided in front of this separation mechanism section,
A pair of upper and lower paper feed rollers 4 are provided in front of the paper feed belt mechanism 3.
However, a detection member 5 for detecting a passing original is provided.

Then, the document that has passed the detection member 5 is transferred to the driving roller 1.
7 and a conveyor belt 18 suspended between the driven roller 16
It is conveyed by a conveyance mechanism 12 having a presser roller 2.
The original is conveyed to a stopper 14 while being pressed against the original placing table 13 by the original 0, and after being exposed to light by an exposure device, the original is ejected onto an ejecting table 15.

The paper feed roller mechanism 2 feeds a document placed on the upper part of the document table 1 at one end of a support arm 32 whose central portion 30 is supported and whose one end is urged upward by a biasing member 31. A feed roller 33 is provided which contacts the upper surface, and the other end of the support arm 32 contacts a member 35 of a drive source (not shown).

The feed roller 33 is movable between a lower position where it contacts the upper surface of the document against the biasing member 31 and an upper position where it is separated from the upper surface of the document by rotation of the eccentric cam 35 by the drive source. It becomes.

Further, in the paper feed belt mechanism 3, a belt 42 is suspended between a pair of rollers 40 and 41 located above the document transport path, and a double feed prevention roller 4 is located below the transport path.
3 is provided at the one end of a support arm 46 whose central portion 44 is supported and whose one end is urged downward by an urging member 45, and whose other end is rotated by a drive source. Eccentric cam 4 mounted on shaft 47
It is in contact with 8.

The double-feed prevention roller 43 is rotated by the rotation of the eccentric cam 48 by the drive source, so that the lower surface of the belt 42, the I
- movable between an upper position in which it abuts and a lower position in which it is slightly separated from said belt 42;

Next, the operation of the above will be explained.

First, when a document is placed on the top of the document table 1, the document is conveyed by a separation mechanism consisting of a paper feed roller mechanism 2 and a paper feed heald mechanism 3, and then transferred to a pair of paper feed rollers 4. being transported and passing through the detection member 5;
The document is conveyed by the conveyance belt 18 and pressed against the document placement table 13 by the presser roller 20, and further conveyed to reach the document stopper 14.

Then, it is exposed to light by an exposure device and discharged onto a discharge table 15.

In such a normal conveyance process, for example, if the size of the document placed on the upper part of the document table 1 is large, so-called synchronous feeding is performed, and as shown in FIG. The roller 33 is in the lower position via the support arm 32 by the eccentric cam 35, and the double feed prevention roller 43 is in the upper position via the support arm 46 by the eccentric cam 48.
The document sent out in step 3 reaches a pair of upper and lower paper feed rollers 4 via a paper feed belt mechanism 3.

After passing through the pair of upper and lower paper feed rollers 4, the presence of the original is detected by the detection member 5, so that each drive source (not shown) is driven by the signal from the detection member 5. Since the eccentric cam 35.48 is rotated,
Moving in the direction of the arrow, the feed roller 33, which is in the lower position, moves to the upper position, and the double feed prevention roller 43, which is in the upper position, moves to the lower position, whereby the paper feed roller mechanism 2 becomes inoperative, and the pressure between the double-feed prevention roller 43 and the belt 42 is weakened, so that the separation mechanism consisting of the paper feed roller mechanism 2 and the paper feed belt mechanism 3 is almost inactive. becomes.

On the other hand, the document is conveyed by a pair of upper and lower paper feed rollers 5, and is further conveyed by a conveyor belt 18 to the document placing table 1.
3, and in the case of this synchronous feeding, since the document stopper 14 is sunk below the upper surface of the document table 13, the document A that has completed exposure is transported at its leading edge. From there, they are sequentially discharged onto the discharge table 15.

Therefore, after the document A is detected by the detection member 5, the separation mechanism hardly acts on the document, so it is difficult to handle large-sized documents where the trailing edge of the document is still located within the separation mechanism. Even when using the conveyor belt 18, there is no resistance to conveyance by the conveyor belt 18.

After the exposed document A is discharged onto the discharge table 15, the feed roller 33 and the double feed prevention roller 43 are in their initial states, that is, the feed roller 33 is in the lower position, and the double feed prevention roller is in the lower position. 43 return to the upper position and prepare for the next copy.

In addition, when copying using the document stop exposure method when the size of the original B placed on the original platen 1 is short, the stopper that was recessed below the top surface of the original platen is moved to a protruding position. , the feed roller 33 and the double feed prevention roller 43 do not change in any way even if the document is detected by the detection member and remain at their initial positions, and operate in the same way as a normal automatic document feeder. .

〔Effect of the invention〕

By virtue of the above-described configuration, the present invention allows the user to place the document on the document table even when copying a large-sized document.
Copying can be done just by placing the document on the paper, and since the document is transported at a constant speed during exposure from the leading edge to the trailing edge, no image disturbances such as unevenness will occur in the copied image. It has excellent effects such as being able to automatically feed even large-sized originals.

[Brief explanation of the drawing]

The drawings show an automatic document feeder according to the present invention; FIG. 1 is a schematic diagram of the overall layout, FIG. 2 is a schematic explanatory diagram showing a case in which a large-sized original is used, and FIG. 3 is an illustration showing a case in which a short-sized original is used. FIG. l...Document table 2...Paper feed roller mechanism 3...Paper feed heald mechanism 4...Paper feed roller 5...Detection member 12... Conveyance unit 13... Document placement table 14... Original stopper 15... Ejection table 16... Driven roller 17... ...Drive roller 18...Transport belt 20...Press roller 30.44...Central portion 31.45...Biasing member 32.46. ...Support arm 33.40.41 ...Roller 34.47 ...Shaft 35.48 ...Eccentric cam 42 ...Belt 43 ...Double feed prevention roller Fig. 2 Fig. 3

Claims (1)

[Claims] In an automatic document feeder that transports a document by a separation mechanism section and a transport section, a detection member is disposed in the transport section,
The automatic document feeder is characterized in that the detection member disables the separation mechanism when it detects that the document is conveyed by the conveyance section after passing through the separation mechanism.