JPH08245005A - Paper feeder - Google Patents

Abstract

PURPOSE: To prevent a plurality of documents from being double fed as well as to exhibit function according to characteristic of each rubber plate so as to improve carrying accuracy, by composing a separating pad in such a manner that a plurality of rubber plates different in characteristics are juxtaposed integrally and symmetrically to the right and the left in a document carrying direction. CONSTITUTION: In a paper feeding part 20, the upper end of a separating pad 24 is attached to an upper guide plate 21, and pushing and pressing force is applied to a pushing and pressing member 23 brought in contact with the back surface of the separating pad 24 by a spring 22 so as to push the front surface of the separating pad 24 to a paper feeding rubber roller 25. A bundle of documents 1 mounted on a document mounting table 10 are sent to a pushing and pressing part between the paper feeding rubber roller 25 and the separating pad 24 by the rotation of the paper feeding rubber roller 25, and the documents prevented from being doubly sent are separated from each other one by one and sent out. In this case, the separating pad 24 consists of a first rubber plate part 24a and a second rubber plate part 24b which are arranged in parallel, integrally and symmetrically to the right and the left in a document carrying direction. Hereby, a plurality of documents are prevented from being double fed as well as to exhibit function according to the characteristics of each rubber plate so as to improve carrying accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder used in a facsimile machine or a copying machine, and more particularly to a document feeder.

[0002]

2. Description of the Related Art Documents are separated and fed one by one from a bundle of documents placed on a document placing table of a document feeding device. The document feeding methods are a friction member separating method, a roller separating method, Belt separation method, vacuum paper feeding method, adhesive paper feeding method, bent paper feeding method, etc. The friction member separation method uses the difference in friction coefficient between the sponge rubber feeding rubber roller and the synthetic rubber plate friction member to separate and feed the originals, and the mechanism is simple. This friction member separating method is generally adopted in a facsimile machine which requires a different shape.

[0003]

In order to satisfactorily separate and feed the originals in the friction member separating method, it is preferable to select the optimum friction member of the rubber material according to the originals. Has the following problems due to its characteristics.

1) The smaller the dynamic friction coefficient of the rubber material used as the friction member, the stronger the tendency of the document to slip in the conveying direction. For this reason, in a facsimile machine, when a document is fed by a friction member made of a rubber material having a small dynamic friction coefficient, an image on the document is read by an image reading unit and a read image is formed on the recording paper, the image is conveyed on the recording paper. There is a problem that the size in the direction becomes larger than the original image on the original.

2) When the rubber material of the friction member is used for a long time, there is a problem that its dynamic friction coefficient changes with the use time, and the size of the image on the recording paper in the carrying direction changes with the use time.

3) During the suspension period of the facsimile apparatus, the rubber material tends to cause a phenomenon called so-called blooming in which the oil content is deposited from the inside, and the degree thereof varies depending on the rubber material. Therefore, if the original document feeder having a friction member using a certain rubber material is stopped for a long time, for example, from evening to morning, and the rubber material is left to stand, the oil component deposited from the rubber material during that time is left in the rubber material. There is a problem that the original attached to the surface of the material and sent at the time of reuse in the morning is double-fed without being separated by the friction member due to oil.

Various rubber materials used as friction members are known, but these rubber materials have advantages and disadvantages, and all the problems 1), 2) and 3) can be solved by a single rubber material. Is difficult.

In the automatic paper feeder disclosed in Japanese Patent Laid-Open No. 5-32337, two kinds of friction members are selected on the assumption that plural kinds of originals having different friction coefficients are sent, and the respective friction members are independent. Two sets of separation pads are configured to be pressed by the pressing spring member. Further, in this paper feeding device, a switching member is provided for the two sets of separation pads so that only the separation pad having a preferable friction member according to a document to be sent is activated by the switching members. ing.
Therefore, in this paper feeding device, the separation pad having two sets of pressing spring members and the switching member are required, so that the number of assembling steps increases, the cost of parts increases, and it becomes difficult to downsize the apparatus. is there. Further, since only one of the two sets of separation pads is operated, the separation force does not act symmetrically on the document, which causes so-called skewing of the document.

It is an object of the present invention to solve the above problems 1), 2) and 3), and to provide a small-sized and inexpensive paper feeder.

[0010]

SUMMARY OF THE INVENTION The above-described object is to provide a sheet feeding device for feeding originals from a bundle of originals placed on an original placing table by pressing a separation pad against a feeding rubber roller to separate and convey the originals one by one. , The separation pad is formed by arranging a plurality of rubber plates having different characteristics integrally in a laterally symmetrical manner in the document conveying direction, and the plurality of rubber plates are simultaneously pressed by the pressing means against the paper feeding rubber roller. This is achieved by a paper feeding device characterized by the above.

The plurality of rubber plates are composed of at least a first rubber plate and a second rubber plate having a friction coefficient smaller than that of the first rubber plate, and the first rubber plate is located at the center of the two rubber plates. It is preferable to dispose the two rubber plates symmetrically on both sides of the first rubber plate.

[0012]

According to the present invention, a plurality of rubber plates having different characteristics are integrally juxtaposed in the original conveying direction, and the paper feed rubber roller is pressed at the same time, so that a function corresponding to the characteristics of each rubber plate is exerted. A separation-type separation pad is configured to improve the conveyance accuracy of the sheet feeding device and prevent double feeding of a plurality of documents.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a main part of a document reading / scanning system of a facsimile apparatus to which the document feeding apparatus of the present invention can be applied.

The original stack 1 to be transmitted is stacked on the original table 10. Under the control of the system control unit, the document detection sensor 11 confirms the presence / absence of a document on the document placing table 10. If there is a document, the sheet feeding unit 20 removes the document from the document stack 1 on the document placing table 10. It is separated and sent out one by one. The originals sent out will continue to be illuminated by the light source lamp 5
2. The sheet is conveyed to the reading unit 50 including the lens 53, the image reading element 54, and the like, and once the leading end reaches the reading position confirmed by the reading position sensor 51, it temporarily stops. After that, the document is conveyed stepwise while the reading position sensor 51 reads the image information by the reading unit 50 for each scanning line.

When the reading position sensor 51 detects the end of the document, the control unit transmits a page end signal of the document, confirms the reception, and the transmitted stamp 55 imprints the transmitted mark on the document. To be done. After that, the document is conveyed by the discharge roller 60 and stored in the discharge tray 65.
When the document discharge sensor 66 of the discharge tray 65 detects that the document discharge is completed, the integration counter counts the number of transmitted pages.

Whether or not the document is normally conveyed is confirmed by a combination of the reading position sensor 51, the document discharge sensor 66, the timer and the counter, and the drive motor is operated for a predetermined time or a predetermined number of steps. Nevertheless, if the document is not detected by the sensor, a jam is displayed as a traveling abnormality.

FIG. 2 is a sectional view showing the structure of the paper feeding section 20. A separation pad 24 used as a friction member has an upper end attached to the upper guide plate 21, and a pressing member 23 is in contact with the back surface of the separation pad 24, and the pressing member 23 is a spring 22.
A pressing force is applied to the front surface of the separation pad 24 against the paper feed rubber roller 25. A bundle of documents stacked on the document table is sent to the pressing portion between the rubber feeding roller 25 and the separation pad 24 by the rotation of the feeding rubber roller 25 in the direction of the arrow, and the double feeding of documents is prevented by the pressing portion. Thus, the originals are separated one by one and sent out.

FIG. 3 is a perspective view showing a pressing portion of the paper feeding portion. The separation pad 24 is a first rubber plate portion 24a and a second rubber plate portion which are arranged in a laterally symmetrical manner integrally in the document conveying direction. It consists of 24b. In the preferred embodiment of the present invention, an EPDM (ethylene propylene rubber) material is used as the first rubber plate 24a having a large friction coefficient, and the second rubber plate having a small amount of internal deposits generated during the stop period of the sheet feeding device is used. BR (butadiene rubber) material is used as 24b. In addition, butadiene isopropyl ethylene propylene rubber can be more preferably used as the EPDM material.

EP using EPDM material and BR material separately
A DM material separation pad and a BR material separation pad were prepared, and a conveyance accuracy test, a aging change test, and an initial double feed test were performed.

A. Conveyance accuracy test In a facsimile machine, while feeding a high-quality paper original by the paper feeding device using each separation pad, the image reading unit reads the image on the original, forms the read image on the recording paper, and forms it on the recording paper. The formed image was compared with the original image on the original. As a result, 1.5% to 1.9% when using the EPDM material separation pad, about 2.5% to 2.8% when using the BR material separation pad. The image formed on the recording paper is more original than the original image on the original. It was observed that it extended in the transport direction. This extension is because the original slips in the feeding direction in the paper feeding section, and the degree of this slip tends to increase as the dynamic friction coefficient of the rubber material of the separation pad decreases.

The dynamic friction coefficient of the EPDM material (about 1.4) is larger than that of the BR material (about 1.0), and as can be seen from the above test results, the extension of the dimension of the formed image on the recording paper in the conveying direction is small. From the point of view, it is preferable to use EPDM material rather than BR material.

B. Time-dependent change test The time-dependent change in the dynamic friction coefficient of EPDM and BR materials was measured by the time-dependent change test by the acceleration method using the air heating aging test (JIS K6301). Specifically, the kinetic friction coefficient was measured after leaving it in a thermostatic chamber at 100 ° C for 15 days.

[0024] As can be seen from the above measurement results, the dynamic friction coefficient of the EPDM material has a larger change over time, and the EPDM material separation pad tends to change the dimension of the formed image on the recording paper in the transport direction with time than the BR material separation pad. It was found to be large.
Therefore, it is more preferable to use the BR material than the EPDM material from the viewpoint of aging.

In the aging test, leaving the sample in a constant temperature room at 100 ° C. for 12 days is equivalent to leaving it in an environment of 40 ° C. for 800 days.

C. Initial double-feed test After leaving the paper feed device for 10 hours, a double-feed test was performed 10 times on each of the BR material separation pad and the EPDM material separation pad to check whether or not there was a double feed by feeding the original. As a result, EPDM
When the material separating pad was used, double feeding occurred 7 times (70%), but when the BR material separating pad was used, double feeding did not occur.

From this, the EPDM material is more likely to deposit oil from the inside due to the blooming phenomenon, and the deposited oil adheres to the surface of the separation pad and cannot separate multiple originals, resulting in double feeding. Cheap. Therefore, it is preferable to use the BR material over the EPDM material from the viewpoint of preventing the initial double feed.

As described above, the EPDM material and the BR material each have advantages and disadvantages, and the above-mentioned three performances cannot be satisfied by themselves. Therefore, in order to utilize the respective advantages of the EPDM material and the BR material to satisfy the above three performances, in the embodiment of the present invention shown in FIG. 3, focusing on the EPDM material having a large friction coefficient,
BR materials having a small coefficient of friction are arranged side by side on both sides thereof integrally in the document conveying direction.

With this configuration, the BR material, which has less oil deposition in the initial use after leaving, exhibits the separating ability to prevent double feeding, and thereafter, in the steady state, EPDM having a large dynamic friction coefficient.
High transport accuracy was maintained by the transport force of the material, and further, the BR material could prevent the transport accuracy from deteriorating significantly over time after long-term use.

[0030]

As described above, according to the present invention, a plurality of rubber plates having different characteristics are integrally juxtaposed in the document conveying direction and the paper feeding rubber roller is pressed at the same time. Since the separation pad of the function separation type that exhibits the above-mentioned function is configured, it is possible to downsize the device without requiring a plurality of sets of pressing members and switching members as in JP-A-5-32337.

Furthermore, the present invention is EP having a large friction coefficient.
The friction coefficient is small on both sides of the DM material.
Since the BR materials are arranged side by side in the document transport direction, skewing of the documents and paper wrinkles can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a document reading / scanning system of a facsimile apparatus to which a document feeding device of the present invention can be applied.

FIG. 2 is a cross-sectional view showing a configuration of a paper feeding unit.

FIG. 3 is a perspective view showing a pressing unit of a paper feeding unit.

[Explanation of symbols]

 1 Document Stack 10 Document Placement Table 20 Paper Feeding Section 21 Upper Guide Plate 22 Spring 23 Pressing Member 24 Separation Pad 24a First Rubber Plate 24b Second Rubber Plate 25 Paper Feeding Rubber Roller

Claims (5)

[Claims] 1. A paper feeding apparatus for pressing a separation pad against a feeding rubber roller for feeding an original from a bundle of originals placed on an original placing table to separate and convey the originals one by one. A plurality of different rubber plates are integrally arranged side by side symmetrically in the document conveying direction, and the plurality of rubber plates are simultaneously pressed by the pressing means against the paper feeding rubber roller. Paper equipment. 2. The plurality of rubber plates are composed of at least a first rubber plate and a second rubber plate having a friction coefficient smaller than that of the first rubber plate, and the first rubber plate is located at the center of the two rubber plates. The paper feeding device according to claim 1, wherein the second rubber plates are arranged so as to be provided symmetrically on both sides of the first rubber plate. 3. The paper feeding device according to claim 1, wherein the first rubber plate is formed of ethylene propylene rubber. 4. The sheet feeding device according to claim 1, wherein the second rubber plate is formed of a rubber material having a small amount of internal deposits generated during a period when the sheet feeding device is stopped. 5. The paper feeding device according to claim 1, wherein the second rubber plate is formed of butadiene rubber.