JP2595509B2 - Paper feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper supply apparatus, and more particularly, to a paper supply apparatus capable of surely setting a paper such as a read original at a paper setting position. is there.

(Prior Art) An example of a conventional paper feeding apparatus will be described with reference to FIG. 8 (for example, Japanese Utility Model Application Laid-Open No. 61-9866). The figure shows a schematic configuration of the document supply apparatus, 2 is a document supply tray, 3 is a feed belt, and 4 is a reverse roll that rotates by contacting the feed belt 3 with an appropriate contact pressure. The fourth shaft holds a bayer 34 which can freely move around the shaft. For this reason, the open end of the bayer 34 constantly presses the feed belt 3 by its own weight.

Reference numeral 5 denotes a document presence / absence detection sensor, reference numeral 6 denotes a first feed roll, reference numeral 7 denotes a first press roll which rotates while being in contact with the first feed roll 6, and reference numeral 8 denotes a scan position sensor.

Reference numeral 10 denotes a platen glass, 11 denotes a second feed roll, 12 denotes a second press roll that rotates while being in contact with the second feed roll 11, and 13 denotes a document discharge tray.

Further, reference numeral 25 denotes a swing frame which can be opened and closed about a fulcrum 26.

Here, the first press roll 7 and the second press roll 12 apply a predetermined pressure to the first feed roll 6 and the second feed roll 11 by a spring (not shown).

In the document supply apparatus having such a configuration, when the document 1 is placed on the document supply tray 2, the document 1 pushes up the baler 34 by its own weight, and the leading end of the document 1 hits the reverse roll 4. At this time, the lowermost document is pushed against the feed belt 3 by the pressing force of the baler 34. Therefore, the friction between the document and the feed belt 3 increases,
After the original is conveyed by the feed belt 3 and passes through the reverse roll 4, the first feed roll 6 and the first feed roll 6
It enters between the press rolls 7 and is further fed. When the leading end of the document is detected by the scan position sensor 8, the rotation of the first feed roll 6 stops, and the document temporarily stops at that position. Next, when the first feed roll 6 is activated at an appropriate timing, the original 1 advances onto the platen glass 10 and is read at the information reading position 9 on the platen glass 10, and thereafter, the second feed roll 11 and the second The document is discharged onto the document discharge tray 13 by the press roll 12.

As described above, when the first document is read,
Since the second document comes into contact with the feed belt 3, this document passes through the reverse roll 4. Thereafter, the original is further fed by the first feed roll 6 and the first press roll 7, and is stopped once when the leading end is detected by the scan position sensor 8. Then, it is sent onto the platen glass 10 at an appropriate timing and is read at the information reading position 9. Hereinafter, the same operation is repeated, and the originals placed on the original supply tray 2 can be read one after another.

In this conventional apparatus, the baler 34 presses the document against the feed belt 3 by its own weight, thereby increasing the friction between the document and the feed belt 3 and bringing the document into close contact with the feed belt 3 to feed the document one sheet at a time. Although it has a function, the baler 34 is always in contact with the feed belt 3 so that, for example, a thin original (35 gf / m or 42 gf / m
(gf / m) is set on the document supply tray 2, there is a problem that the leading edge of the document stops at the contact portion between the baler 34 and the feed belt 3 and does not advance further. Was. In addition, there is a problem that the original is sometimes damaged when the user tries to set it forcibly.

One solution to this problem is disclosed in Japanese Utility Model Laid-Open No. 58-123841. This publication discloses an upper conveying roller for conveying a sheet, a pressure roller supporting member rotatably supported on a shaft of the upper conveying roller, and a paper feeding pressure roller supported by the pressure roller supporting member. Prepared,
There is disclosed an automatic document feeder in which the pressure roller supporting member rotates upward when no sheet is on the sheet holding table. According to this apparatus, when feeding only one thin document, the pressure roller for sheet feeding rotates upward, and when the thin document is placed on the sheet feeding table, the pressure roller for sheet feeding moves downward. As a result, the document is prevented from moving forward and the document is not damaged.

(Problems to be Solved by the Invention) However, this automatic document feeder cannot prevent a case where two or more sheets of paper, that is, a document are fed at a time (that is, a case where double feeding is performed). Japanese Patent Publication No. 50-40603 discloses the use of a roller for feeding paper in reverse as a device for preventing double feeding of paper.

In view of this, it is conceivable to create a device that enables document feeding and document double feeding prevention by combining the automatic document feeding device and the double feeding prevention device. The multi-feed paper that has been fed back by the feeding roller is prevented from being fed back by the pressure roller for feeding paper, and Z
There has been a risk that breakage may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems of the conventional apparatus and to provide a document feeding apparatus in which Z-folding or the like does not occur in a multi-fed sheet.

(Means and Action for Solving the Problems) In order to solve the above problems, the present invention provides a feed belt that conveys a sheet, and a naja roll that rotates in contact with or close to the feed belt. And a reverse roller that rotates in contact with or close to the feed belt and the naja roll on the downstream side in the paper transport direction, wherein the reverse roll rotates in a direction to push back the paper on the feed belt. At this time, the present invention is characterized in that there is provided a means for rotating the naja roll in the same direction as the reverse roll, and for making the linear velocity of the naja roll higher than the linear velocity of the reverse roll.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. First, an example of a sheet feeding apparatus that can feed a single thin sheet without fail and prevent double feeding of the sheet will be described. FIG. 1 is a perspective view of a main part of the paper supply apparatus. In the figure,
The same reference numerals as those in FIG. 8 indicate the same or equivalent parts.

In the figure, reference numeral 14 denotes Najarol,
It has the same function as 34. This Najarol 14
Is rotatably supported on the naja bracket 15 by a bearing 16a and an E-ring 17a. The naja bracket 15 is rotatably supported on a reverse shaft 30 by a bearing 16b and an E-ring 17b, and the reverse roll 4 is supported on the reverse shaft 30 via a PTL (powder torque limiter). Therefore, the reverse roll 4 rotates in the same direction as the reverse shaft 30 when the torque is equal to or less than the set torque. On the other hand, when the reverse roll 4 is given a torque equal to or more than the set torque in the direction opposite to the rotation direction of the reverse shaft 30, the reverse roll 4 rotates in the opposite direction to the reverse shaft 30.

A stud portion 15a is integrally formed or fixed to the naja bracket 15, and the stud portion 15a
A nut 18 is fixed at an appropriate position 15a. One end of a wire 20 is fixed to the nut 18, and the other end is fixed to an open end of the arm 21.

The other end of the arm 21 is rotatable by a bearing arm 22 and a screw 23 on an arm fulcrum boss 25a as shown in a sectional view (a sectional view taken along line AA in FIG. 1) enlarged in FIG. Attached. The tongue extending downward from the center of the arm 21 faces the solenoid 19.

The open end of the arm 21 is connected to a spring 24, and the other end is locked by a spring stopper 25c. For this reason, the arm 21 reciprocates in the direction of arrow A when the solenoid 19 is turned on and off. The arm 21
Moves to the right of arrow A, the wire 20 is loosened, and the naja roll 14 falls on the feed belt 3 by its own weight.
Conversely, when the arm 21 moves to the left of the arrow A, the wire 20 becomes taut. Thus, the naja bracket 15 rotates counterclockwise about the reverse shaft 30, and the naja roll 14 is lifted from the feed belt 3 by a predetermined distance.

A pulley for rotating the feed belt 3, a first feed roll 6, a platen glass 10, and a second feed roll 11, and a document presence sensor 5, a scan position sensor 8, and a document discharge tray 13 (not shown) are provided. Are attached to a base frame (not shown). The feed belt 3 is driven by a pulse motor via an electromagnetic clutch and gears (not shown). Furthermore, reverse roll 4, naja roll 14, naja bracket 15, stud part
15a, a structure comprising a nut 18 and a wire 20, and a structure comprising a solenoid 19, an arm 21, a bearing arm 22, a screw 23 and a spring 24, a first press roll 7 and a second press roll 12, etc. It is attached to the frame 25.

Further, as shown in a partially detailed perspective view in FIG. 3, the reverse shaft 30 is configured to transfer an original from the first feed roll 6 to the first feed roll gear 31, the idle gear 32, and the reverse roll gear 33 by the respective gears. It is receiving a driving force in the direction of pushing back. As an example, the Naja roll 14 is a SUS roll having a surface finish of about 3S (weight of about 80 gf).
Can be used.

Next, the operation of the paper feeding apparatus having the above configuration will be described with reference to FIGS. FIG. 4 and FIG. 5 are schematic structural views of FIG. 1 when the wire 20 is tensioned and relaxed, respectively.

In the initial state of the facsimile machine, copying machine, etc., the solenoid 19 is turned off, the wire 20 is pulled by the spring 24, and the naja roll 14 is lifted, as shown in FIG. When a document is set in this state, the leading edge of the document reaches a position where it contacts the peripheral surface of the reverse roll 4. Next, when the document transmission button or the copy button of the facsimile apparatus is pressed, the solenoid 19 is turned on, and the wire 20 is in a relaxed state as shown in FIG. Then, the naja roll 14 falls on the original document by its own weight, and applies a vertical force to the original document to press it.

When the original is pressed by the naja roll 14, the friction between the lowermost original and the feed belt 3 increases, and the original moves together with the feed belt 3 and is conveyed. When the leading edge of the document reaches between the first feed roll 6 and the first press roll 7, the document is conveyed by the first feed roll 6 and the first press roll 7, as in the conventional apparatus. When the leading edge of the document is detected by the scan position sensor 8, the document is temporarily stopped, the solenoid 19 is turned off, and the naja roll 14 is lifted.

At a suitable timing, the conveyance of the document is restarted, the reading of the document proceeds, and when the rear end of the document is detected by the scan position sensor 8, the solenoid 19 is turned on again to draw in the next document. Thus, the next document is sent between the first feed roll 6 and the first press roll 7 in the same manner as described above.

The above operation is repeated, and when the absence of the document on the document supply tray 2 is detected by the document presence / absence detection sensor 5, even if the rear end of the document currently being read by the scan position sensor 8 is detected. ,
The solenoid 19 is formed so as not to be started next time.

Therefore, when a document is set on the document supply tray 2 for reading the next document information, since the wire 20 is in a tensioned state and the naja roll 14 is lifted, even if there is only one thin document, Even if the document is set on the document supply tray 2, the problem that the leading end of the document is caught on the naja roll 14 and reading of the document fails is eliminated.

By the way, the paper feeding device having the above-described configuration
14 can sufficiently solve the problem that the leading edge of a thin document is caught on the feed belt.
When the original comes into contact with the reverse roll 4, there is a possibility that the original may not be fed normally, especially when the original on which the original is placed is a thin original similar to that described above. there were.

That is, as shown in FIG.
When the rolls 1a and 1b overlap and enter between the reverse roll 4 and the feed belt 3, the reverse roll 4 is rotated in the opposite direction to the feed belt 3, so that the original 1b on the upper side is shown in FIG. It is pushed back as shown in b) and is prevented from passing between the reverse roll 4 and the feed belt 3. This prevents double feeding. However, when the original 1b is a particularly thin original, a mountain-shaped slack X is formed between the reverse roll 4 and the naja roll 14, and then the original 1b is When sent, the same figure (c)
As shown in (1), there is a possibility that Z-folding Y may occur in the original.

The present invention solves this fear. In the apparatus shown in FIG. 1, a timing pulley is provided at one end of the reverse roll 4 as shown in FIG.
4a is integrally formed, and a timing pulley 14a is integrally formed at one end of the naja roll 14 on the same side as the above, and these pulleys 4a and 14a are connected by a belt 40.

According to the present embodiment, when the originals 1a and 1b overlap and enter the contact position between the reverse roll 4 and the feed belt 3, the original 1b on the upper side is pushed back by the reverse roll 4, but at this time Since the roll 14 is also rotating in the same direction as the reverse roll 4, the original 1 b does not form a mountain-shaped sag between the reverse roll 4 and the naja roll 14.

In this embodiment, when the linear velocity of the reverse roll 4 is v _R and the linear velocity of the naja roll 14 is v _N , v _R <
v is _N, and v _N a v is good to be 2-3% greater than _R.

(Effects of the Invention) As is apparent from the above description, according to the present invention, even when two sheets overlap and hit the reverse roll, the naja roll is in the same direction as the reverse roll and v _R < v _N
, It is possible to surely prevent a mountain-shaped slack, a Z-fold, or the like from being generated in the paper stacked on top. Therefore, the sheet can be reliably supplied to the reading position on the platen and the sheet transport path.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a paper feeding apparatus to which the present invention is applied, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is an example of a configuration for applying a driving force to a reverse roll. Perspective view,
FIGS. 4 and 5 are schematic structural views of the paper feeding apparatus when the wire is in a tensioned state and a relaxed state, respectively. FIG. 6 is a view showing a state in which a document is Z-folded, and FIG. FIG. 8 is a schematic diagram showing the configuration of a main part of a conventional apparatus according to an embodiment of the present invention. 3 ... feed belt, 4 ... reverse roll, 14 ...
Naja roll, 15 Naja bracket, 19 Solenoid, 20 Wire, 21 Arm, 24 Spring, 34 Baylor, 40 Belt

Claims (1)

(57) [Claims] 1. A feed belt on which a sheet bundle is placed and a sheet is conveyed from the lowest one of the sheet bundle, and a feed belt is disposed to face the feed belt, and a pressing force on the feed belt is set. A reverse roll that rotates so as to push back the paper on the feed belt in the anti-feeding direction when the torque is equal to or less than the reverse belt;
A naja roll provided so as to press by its own weight on the upper surface of the uppermost sheet of the sheet bundle arranged on the feed belt; and when the reverse roll rotates in the anti-feeding direction, the naja roll is Means for rotating the reverse roll in the rotation direction at a linear velocity higher than the linear velocity of the reverse roll.