GB2304696A

GB2304696A - Automatic document feeders

Info

Publication number: GB2304696A
Application number: GB9608397A
Authority: GB
Inventors: Heung-Kyu Jang
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1995-08-10
Filing date: 1996-04-23
Publication date: 1997-03-26
Anticipated expiration: 2016-04-23
Also published as: KR0131009Y1; GB2304696B; GB9608397D0; KR970010756U

Abstract

A facsimile system has an automatic document feeding device in which a pinch roller 24 is installed so as to come in contact with a surface of a feed roller 10 in order to increase a feed force of the document. The automatic document feeding device includes: a paper sensor 18 sensing a document thereby to drive a motor; the feed roller 10 operating through a driving force of the motor; a friction pad 16 separating one by one a plurality of documents 14; the pinch roller 24 installed on an upper cover 20 of the device; a read out sensor 30 sensing a delivered position of a document 14; an image sensor 28 receiving data from the read out sensor 30 to thereby read out and transmit data from a document 14; and a white roller 26 for discharging a delivered document 14.

Description

AUTOMATIC DOCUMENT FEEDERS This invention relates to automatic document feeders, and is concerned particularly, although not exclusively, with such document feeders in facsimile machines.

Figure 1 of the accompanying diagrammatic drawings shows a structure of a conventional automatic document feeding device of a facsimile system. As shown in Figure 1, the conventional document feeding device comprises a feed roller 40, a friction pad 46, a document sensor 48, a read out sensor 56, an image sensor 54 and a white roller 52.

The feed roller 40 operates through a driving force of a motor. The friction pad 46 for separating one by one a plurality of documents is installed so as to come in contact with an upper side of the feed roller 40. The document sensor 48 for sensing a document 44 thereby to drive the motor is installed at an upper portion of the paper feed roller 40. The read output sensor 56 for sensing a delivered document 44 is installed at an output side of the feed roller 40. The image sensor 54 for reading out and transmitting data is installed to one side of the read out sensor 56. The white roller for discharging the delivered document 44 is installed at an upper portion of the image sensor 54.

In Figure 1, if documents 44 are stacked on a bottom cover 42, the document sensor 48 senses the uppermost document 44 and thus the motor (not shown) rotates, and the feed roller 40 feeds one by one each document 44 along a feed path while rotating counterclockwise through the driving force of the motor. At this time, a frictional force generated between the feed roller 40 and the document 44 is stronger than that between the documents or between the document 44 and the friction pad 46, and accordingly, the document 44 is delivered toward the read out sensor 56.

Then, the read out sensor 56 senses the delivered position of the document 44 thereby to control a read out timing.

The document 44 is delivered between the white roller 52 and the image sensor 54, and at this time, data contained in the document 44 is coded and compressed by the image sensor 54 to be read out and transmitted. Then, the document 44 is discharged through a rotary force of the white roller 52.

In use as described above, the operations of separating and feeding one by one the plurality of documents 44 are simultaneously performed by using the different friction forces of the friction pad 46 for separating one by one the plurality of the documents and the feed roller 40 for feeding one by one the plurality of documents. The frictional force, friction area and friction pressure and so on of the friction pad 46 (eg of rubber materials) can be controlled accordingly. The friction pad 46 has to be designed to have a weaker friction force than the feed roller 40, so that the document 44 may be delivered.

However, feed conditions are changed according to the kind and thickness of the document 44 and also, feed rates of the document 44 change according to the feed conditions.

For example, if the document 44 is thick or has a coated smooth surface, this can result in several problems as follows. First, the coefficient of friction of the document 44 is changed and thereby, the document 44 is fed at a different feed rate compared to a regular feed condition. Accordingly, slip in the feed roller 40 may be generated and thereby, the document 44 may not be taken up in a required period of time. Second, since the document 44 is fed at a different feed rate compared with the regular feed rate, the document may be fed at an irregular feed rate in the section between the white roller 52 and the image sensor 54 and accordingly, the read out rate and the sensing rate become different from each other.

Thereby, the recorded image may be spread more than the original image. Third, if the document 44 is not taken up or the take-up thereof is delayed, a paper jam condition is generated and consequently, the performance of the machine may be poor. To resolve theses problems, a drive roller and a pinch roller can be additionally provided between the feed roller 40 and the white roller 52.

However, this results in other problems in that the cost of the machine is increased due to the high price of the additional rollers, and a limitation on space for installing the additional parts is generated due to the number of the additional parts capable of providing the overall driving force being increased. Furthermore, as the size of the machine is increased, a limitation on the design of the machine is generated.

Preferred embodiments of the present invention aim to provide an automatic document feeding device of a facsimile system, capable of preventing a recorded image of a document from being spread more than an original image thereof.

It is another aim to provide an automatic document feeding device capable of preventing a paper jam condition due to a document being not inserted.

It is yet another aim to provide an automatic document feeding device capable of increasing document feed rate.

It is still another aim to provide an automatic document feeding device having a read out rate and a sensing rate which are equal to each other.

It is a further aim to provide an automatic document feeding device improved in cost and quality aspects thereof.

It is a further aim to provide an automatic document feeding device having fewer limitations on the design of the product, by minimizing its size.

According to one aspect of the present invention, there is provided an image sensing device including an automatic document feeder which comprises: a paper sensor for sensing a document to be fed, thereby to drive a motor; a feed roller driven by said motor to feed a document; a friction pad cooperating with said feed roller to separate one by one a plurality of documents to be fed; a pinch roller cooperating with said feed roller to feed a document; a read out sensor for sensing a delivered position of a document delivered by said feed roller; an image sensor for reading an image on a document delivered by said feed roller; and a discharge roller for discharging a document from the feeder.

Preferably, said pinch roller is urged resiliently against said feed roller by resilient bias means.

Preferably, said pinch roller and resilient bias means are mounted on a cover of said device.

Preferably, said resilient bias means comprises a spring.

Preferably, said spring is a plate spring.

An image sensing as above may be a facsimile transmitting device, and include means for transmitting data representing an image read by said image sensor.

Preferably, said discharge roller is a white roller.

According to another aspect of the present invention, there is provided an automatic document feeder which comprises: a paper sensor for sensing a document to be fed, thereby to drive a motor; a feed roller driven by said motor to feed a document; a friction pad cooperating with said feed roller to separate one by one a plurality of documents to be fed; and a pinch roller cooperating with said feed roller to feed a document.

An automatic document feeder as above may further comprise any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to Figures 2 and 3 of the accompanying diagrammatic drawings, in which: Figure 2 is a schematic diagram illustrating the structure of one example of an automatic document feeding device structured according to one embodiment of the present invention; and Figure 3 shows different operational views of the automatic document feeding device of Figure 2, as compared with a conventional device.

As shown in Figures 2 and 3, the automatic document feeding device comprises a feed roller 10, a friction pad 16, a document sensor 18, a pinch roller 24, a plate spring 22 of resilient material, a read out sensor 30, an image sensor 28 and a white roller 26. Here, the feed roller 10 is operated through a driving force of a motor.

The friction pad 16 is installed so as to come in contact with an upper side of the feed roller 10, and separates one by one a plurality of the documents 14. The document sensor 18 installed in the upper portion of the friction pad 16 senses the documents 14 thereby to drive the motor.

The pinch roller 24 for increasing a feed force of the document 14 is installed in an upper cover 20 while being positioned between one end of the friction pad 16 and the feed roller 10, and installed so as to bear against a surface of the feed roller 10 with a predetermined pressure, due to the spring 22 of resilient materials.

The pinch roller 24 and the plate spring 22 are assembled together in the upper cover 20.

The read out sensor 30 for sensing the delivered position of the document 14 is installed at the output side of the feed roller 10, and the image sensor 28, which receives position data of the read out sensor 30 thereby to read out or transmit received data, is installed to one side of the read out sensor 30. The white roller 26 for discharging the document 14 is installed at the upper portion of the image sensor 28.

In use of the device, a document 14 is provided on the bottom cover 12 of the facsimile system, the document sensor 18 senses the document 14 and then the motor (not shown) rotates. Then, the feed roller 10 feeds the document 14 along the feed path while rotating counterclockwise (as seen in Figure 2) through the driving force of the motor. At this time, the frictional force between feed roller 10 and the document 14 is stronger than that between the documents, or between the document 14 and the friction pad 16 and therefore, the document is delivered to the position of the read out sensor 30. The pinch roller 24 and the feed roller 10 are in contact with each other by the predetermined force, to thereby jointly rotate as shown in Figure 3, and therefore the document 14 can be delivered without loss of the feed force.

As shown in Figure 3, the pinch roller 24 exerts a force F on the paper 14, substantially radially of the feed roller 10. On the other hand, the force F exerted by the friction paid 16 per se on the paper 14 has a tangential component, in a direction opposite to that of the movement of the paper 14. Thus, the pinch roller 24 significantly improves reliable feeding of the paper 14, and reduces any tendency of the paper 14, and reduces any tendency of the paper 14 to slip on the feed roller 10 due to the tangential force component exerted by the friction paid 16. Since the pinch roller 24 co-operates directly with the feed roller 10 rather than an additional drive roller, negligible extra space may be required for the pinch roller 24 and its resilient bias means 22, which are conveniently located on the upper cover 20 (eg an opening cover of the device).

The read out sensor 30 senses the position of the document 14 thereby to control the read out timing of data, and then the document 14 is delivered between the white roller 26 and the image sensor 28. At this time, data contained in the document 14 is coded and compressed by the image sensor 28 thereby to be read out and transmitted. The document 14 is then discharged by the rotary force of the white roller 16.

In the automatic document feeding device of the facsimile system as mentioned above, there are some advantages.

First, the feed force of the feed roller 10 works in the feed direction of the document 14 without slip due to the pressure of the pinch roller 24 which jointly rotates with the feed roller 10, and therefore the feed force of the document 14 is increased. Second, since the feed force is increased, the recorded image is prevented from being spread. Thereby, an image quality of high resolution can be achieved and generation of a paper jam due to the delay of document insertion or take-up can be prevented. Third, a separate drive roller, with respective pinch roller and additional parts for providing an overall driving force are not required. Therefore, there are fewer limitations on space for installing additional parts of the product, the cost of the product is reduced, and further, the size thereof is minimized.

In this specification, terms of absolute orientation are used conveniently to denote the usual orientation of items in normal use and/or as shown in the accompanying drawings. However, such items could be disposed in other orientations, and in the context of this specification, terms of absolute orientation, such as "top", "bottom", "left", "right", "vertical" or "horizontal", etc. are to be construed accordingly, to include such alternative orientations.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. An image sensing device including an automatic document feeder which comprises: a paper sensor for sensing a document to be fed, thereby to drive a motor; a feed roller driven by said motor to feed a document; a friction pad cooperating with said feed roller to separate one by one a plurality of documents to be fed; a pinch roller cooperating with said feed roller to feed a document; a read out sensor for sensing a delivered position of a document delivered by said feed roller; an image sensor for reading an image on a document delivered by said feed roller; and a discharge roller for discharging a document from the feeder.

2. An image sensing device according to claim 1, wherein said pinch roller is urged resiliently against said feed roller by resilient bias means.

3. An image sensing device according to claim 2, wherein said pinch roller and resilient bias means are mounted on a cover of said device.

4. An image sensing device according to claim 2 or 3, wherein said resilient bias means comprises a spring.

5. An image sensing device according to claim 4, wherein said spring is a plate spring.

6. An image sensing device according to any of the preceding claims, being a facsimile transmitting device, and including means for transmitting data representing an image read by said image sensor.

7. An image sensing device according to any of the preceding claims, wherein said discharge roller is a white roller.

8. An image sensing device substantially as hereinbefore described with reference to Figure 2 or Figures 2 and 3 of the accompanying drawings.

9. An automatic document feeder which comprises: a paper sensor for sensing a document to be fed, thereby to drive a motor; a feed roller driven by said motor to feed a document; a friction pad cooperating with said feed roller to separate one by one a plurality of documents to be fed; and a pinch roller cooperating with said feed roller to feed a document.

10. An automatic document feeder according to claim 9, further comprising any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

11. An automatic document feeder substantially as hereinbefore described with reference to Figure 2 or Figures 2 and 3 of the accompanying drawings.