JP2005247523A - Sheet feeder and printing device using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of preventing double feeding of sheets without obstructing travelling of the sheets such as recording paper to be fed or the like, and a printing device using this. <P>SOLUTION: The sheet feeder is provided with a sheet holding part for holding a plurality of sheets P<SB>1</SB>-P<SB>5</SB>; a pick up roller 3 for feeding out the sheets P<SB>1</SB>-P<SB>5</SB>of the sheet holding part through a sheet feed passage 2 one sheet at a time; a separation pad urged to the pick up roller 3; and an auxiliary roller 5 arranged opposing to the pick up roller 3 while clamping the sheet feed passage 2 and rotated by friction force generated by contact with the pick up roller 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet supply apparatus that supplies a single sheet such as paper or an overhead projector (OHP) sheet one by one and a printing apparatus such as a facsimile, a printer, and a copier using the sheet supply apparatus.

  2. Description of the Related Art Conventionally, printing apparatuses such as facsimiles, printers, and copiers are provided with a sheet supply device for supplying a plurality of sheets held in advance and a single sheet (cut sheet) such as an OHP sheet. Yes. This type of sheet supply apparatus includes a separation pad for separating and supplying the sheets to be held one by one.

  For example, FIG. 4 of (Patent Document 1) describes a separation pad that is urged against a paper feed roller. Since the recording paper fed out by the paper feeding roller is sandwiched between the paper feeding roller and the separation pad urged against the paper feeding roller, the recording paper is lower than the uppermost recording paper by the frictional force of the separation pad. Therefore, only the uppermost recording sheet in contact with the sheet feeding roller is advanced and fed.

Further, in FIG. 2 of Patent Document 1, the pad holding member is uniformly pressed against the paper feed roller by urging the pad holding member from the back surface by a spring on a perpendicular to the paper feed roller. There is a description in which the center of swinging of the holding member and the center of the pad holding member are not greatly deviated, and the pressure between the paper feed roller and the separation pad is maintained in parallel.
Japanese Patent Laid-Open No. 7-251967

  In the conventional separation pad, it is possible to prevent double feeding of the recording paper that is in contact with the separation pad by its frictional force. However, with the conventional separation pad, when the uppermost recording paper to be fed comes in contact with the lower recording paper that is not to be prevented from proceeding, there is a possibility that the progress of the uppermost recording paper to be fed is also obstructed. is there.

  When the progress of the uppermost recording sheet to be fed is prevented in this way, a feeding error occurs and printing cannot be performed normally.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet supply device that prevents double feeding of sheets without obstructing the progress of a sheet such as recording paper to be supplied, and a printing apparatus using the sheet supply device.

  In order to solve the above-described problems, the present invention provides a sheet holding unit that holds a plurality of sheets, a sheet supply roller that feeds the sheets of the sheet holding unit through a sheet supply path, and a separation that is biased with respect to the sheet supply roller. A pad and an auxiliary roller that is arranged to face the sheet supply roller across the sheet supply path and rotate by frictional force generated by contact with the sheet supply roller.

According to the present invention, until the sheet to be supplied is sandwiched between the sheet supply roller and the auxiliary roller, the auxiliary roller is rotated by the frictional force generated by the contact with the sheet supply roller, and the sheet to be supplied is The sheet is fed to the sheet supply roller by the auxiliary roller. In addition, after the fed sheet is sandwiched between the sheet supply roller and the auxiliary roller, the auxiliary roller is not in direct contact with the sheet supply roller, so that the rotation stops and the sheet under the sheet to be supplied Is kept on the separation pad to prevent its progress. Thereby, it is possible to prevent double feeding of sheets without hindering the progress of the sheets to be supplied.

  According to the first aspect of the present invention, a sheet holding unit that holds a plurality of sheets, a sheet supply roller that sends out the sheets of the sheet holding unit through a sheet supply path, and a separation that is biased with respect to the sheet supply roller The sheet supply apparatus includes a pad and an auxiliary roller that is disposed to face the sheet supply roller across the sheet supply path and rotates by frictional force generated by contact with the sheet supply roller. According to the present invention, until the sheet to be supplied is sandwiched between the sheet supply roller and the auxiliary roller, the auxiliary roller is rotated by the frictional force generated by the contact with the sheet supply roller, and the sheet to be supplied is The sheet is fed to the sheet supply roller by the rotation of the auxiliary roller. In addition, after the fed sheet is sandwiched between the sheet supply roller and the auxiliary roller, the auxiliary roller is not in direct contact with the sheet supply roller, so that the rotation stops and the sheet under the sheet to be supplied Is kept on the separation pad to prevent its progress. Thereby, it is possible to prevent double feeding of sheets without hindering the progress of the sheets to be supplied.

  According to a second aspect of the present invention, there is provided a sheet feeding apparatus including a regulating member that regulates a width of the sheet feeding path so that only one uppermost sheet of the sheet holding portion is in contact with the sheet feeding roller. It is a thing. According to the present invention, only one uppermost sheet of the sheet holding portion to be supplied comes into contact with the sheet supply roller, and only this sheet is sent out by the sheet supply roller. This further prevents sheet double feeding.

  According to a third aspect of the present invention, there is provided a sheet supply apparatus including a load member that applies a load to the rotation of the auxiliary roller. After the sheet to be supplied is fed to the sheet supply roller by the rotation of the auxiliary roller and is sandwiched between the sheet supply roller and the auxiliary roller, the auxiliary roller does not directly contact the sheet supply roller. Since the load is applied to the rotation of the roller by the load member, the auxiliary roller can be prevented from rotating due to the frictional force with the sheet fed by the sheet supply roller. Thereby, it becomes possible to further prevent the sheets from being double fed.

  According to a fourth aspect of the present invention, the auxiliary roller is a sheet feeding device made of resin. According to the present invention, when the sheet is sandwiched between the sheet supply roller and the auxiliary roller, the frictional force generated by the contact between the auxiliary roller and the sheet is reduced. As a result, the auxiliary roller can be prevented from rotating due to the frictional force with the sheet fed by the sheet supply roller, and the sheet can be prevented from being double fed.

  According to a fifth aspect of the present invention, there is provided a sheet feeding apparatus having a surface with irregularities on the surface of the auxiliary roller. According to the present invention, the end portion of the sheet to be supplied is applied to the irregularities on the surface of the rotating auxiliary roller, and the sheet is fed between the sheet supply roller and the auxiliary roller. As a result, even if the auxiliary roller is made of resin and has a small frictional force with the sheet, the sheet to be reliably supplied is fed between the sheet supply roller and the auxiliary roller, and the progress of the sheet to be supplied is prevented. Therefore, it is possible to prevent double feeding of sheets.

According to a sixth aspect of the present invention, the auxiliary roller is a sheet supply device made of rubber. According to the present invention, the frictional force between the auxiliary roller and the sheet increases, and the frictional force can reliably feed the sheet between the sheet supply roller and the auxiliary roller. In this case, the auxiliary roller continues to rotate due to the frictional force between the sheet and the auxiliary roller even if the sheet to be supplied is sandwiched between the sheet supply roller and the auxiliary roller. When the nip portion is reached, the rotation stops and the progress of the sheet under the sheet to be fed is prevented by the frictional force. Thereby, it is possible to prevent double feeding of sheets without hindering the progress of the sheets to be supplied.

  A seventh aspect of the present invention is a printing apparatus provided with the above sheet supply apparatus. According to the present invention, it is possible to obtain a printing apparatus that prevents double feeding of sheets without disturbing the progress of sheets such as recording paper to be supplied.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view of a sheet supply apparatus provided in a printing apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view of the sheet supply apparatus without the sheet supply roller of FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along line -A, and FIG. 4 is a cross-sectional view taken along line BB in FIG.

As shown in FIGS. 1 to 4, the sheet feeding apparatus 1 provided in the printing apparatus (not shown) according to the first embodiment of the present invention includes a plurality of sheets P ₁ , P ₂ , P ₃ , P ₄ , A sheet tray (not shown) as a sheet holding unit that holds P ₅ and sheets P _{1 to} P ₅ of the sheet tray are sent one by one to the printing unit (not shown) through the sheet supply path 2. A pickup roller 3 as a supply roller, a separation pad 4 urged against the pickup roller 3, an auxiliary roller 5 disposed opposite to the pickup roller 3 across the sheet supply path 2, and the width of the sheet supply path 2 And a regulating member 6 that regulates the above.

  The separation pad 4 is fixed to a separation pad holder 7 that can swing around a rotation shaft 7a. The rotation shaft 7 a is provided at the end of the separation pad holder 7 on the sheet tray side. The rotary shaft 7a is rotatably held on the sheet tray. Further, the separation pad holder 7 has its end opposite to the rotation shaft 7a of the separation pad holder 7 pressed against the pickup roller 3 by a spring 7b. In this way, the separation pad holder 7 is pressed toward the pickup roller 3 by the spring 7 b, whereby the separation pad 4 on the separation pad holder 7 is urged against the pickup roller 3.

  The auxiliary roller 5 is rotatably supported by auxiliary roller holders 8 provided on the left and right sides of the separation pad holder 7 respectively. FIG. 5 is an exploded view of the auxiliary roller 5 and the auxiliary roller holder 8. As shown in FIG. 5, the auxiliary roller 5 is supported on a support shaft 8 a of the auxiliary roller holder 8 via a coil spring 9 as a load member. The auxiliary roller 5 is given a load by its coil spring 9 in its rotation.

  The auxiliary roller holder 8 is rotatably held by the rotation shaft 8b at the end of the separation pad holder 7 opposite to the rotation shaft 7a. Further, the auxiliary roller holder 8 has its end opposite to the rotating shaft 8b (sheet tray side) pressed against the sheet tray side by a spring 8c.

  FIG. 6 is an enlarged sectional view of the auxiliary roller 5. As shown in FIG. 6, the surface of the auxiliary roller 5 is periodically provided with recesses 5a and protrusions 5b. The end surface of the convex portion 5b on the rotation direction (counterclockwise direction in FIG. 6) side of the auxiliary roller 5 has a shape that rises from a bottom of the concave portion 5a with a sharp curved surface, and the opposite end surface has a gentle slope with the concave portion 5b. The shape is connected to the bottom of

In the present embodiment, the pickup roller 3 is a long cylindrical roller made of ethylene propylene rubber (EPDM). On the other hand, the auxiliary roller 5 is made of polyoxymethylene (POM) resin as a resin. The auxiliary roller 5 formed of such a resin rotates following the pickup roller 3 by a frictional force generated by contact with the pickup roller 3.

The regulating member 6 regulates the width of the sheet supply path 2 so that only one uppermost sheet (P _{1 in the} illustrated example) of the sheets P _{1 to} P ₅ of the sheet tray contacts the pickup roller 3. .

In the sheet feeding apparatus 1 having the above configuration, when nothing is interposed between the pickup roller 3 and the auxiliary roller 5, the auxiliary roller 5 rotates following the pickup roller 3 by the frictional force generated by the contact. Then, one sheet P _{1 on} the uppermost surface of the sheet tray is regulated by the regulating member 6 to come into contact with the pickup roller 3 and fed between the pickup roller 3 and the auxiliary roller 5.

At this time, the sheet P ₁ is further supplementarily fed between the pickup roller 3 and the auxiliary roller 5 by the auxiliary roller 5 that rotates following the pickup roller 3. The auxiliary roller 5, since the recess 5a and the convex portion 5b is provided, the ends of the sheet P ₁ is applied to the these recesses 5a and the convex portion 5b, the sheet P ₁ is more reliably the pickup roller 3 auxiliary roller It is sent in between 5.

The sheet P ₁ fed between the pickup roller 3 and the auxiliary roller 5 is sandwiched between the pickup roller 3 and the auxiliary roller 5, but the auxiliary roller 5 does not directly contact the pickup roller 3 here. The rotation stops, the sheets P _{2 to} P ₅ under the sheet P ₁ to be supplied are retained on the separation pad 4 and the progress is prevented. As a result, only the sheet P ₁ is sent to the printing unit through the sheet supply path 2.

As described above, according to the sheet feeding apparatus in the present embodiment, it is possible to prevent the double feeding of the underlying sheets P _{2 to} P ₅ without hindering the progress of the sheet P ₁ to be fed. . Further, in the present embodiment, since only the sheet P ₁ to be supplied in a single uppermost surface of the sheet holder is in contact with the pickup roller 3 by the regulating member 6, only the sheet P ₁ is the pick-up roller 3 In this case, the sheet is prevented from being double fed.

Further, in the present embodiment, since the coil spring 9 that applies a load to the rotation of the auxiliary roller 5 is provided, the auxiliary roller 5 is moved by the pickup roller 3 after the auxiliary roller 5 is not in direct contact with the pickup roller 3. It is possible to prevent rotation due to frictional force with the sheet P ₁ to be sent out. Thereby, it becomes possible to further prevent the sheets from being double fed.

Further, in this embodiment, since the auxiliary roller 5 is made of resin, when the sheet P ₁ is sandwiched between the pickup roller 3 and the auxiliary roller 5, by contact with the auxiliary roller 5 and the sheet P ₁ The resulting frictional force is reduced. As a result, the auxiliary roller 5 can be prevented from rotating due to the frictional force with the sheet P ₁ delivered by the pickup roller 3, and further, it is possible to prevent double feeding of the sheets.

Further, by providing the recess 5a and the convex portion 5b on the surface of the auxiliary roller 5, take the recess 5a and the convex portions 5b of the surface of the auxiliary roller 5 the end of the sheet P ₁ to be supplied is rotated, the sheet P ₁ is fed between the pickup roller 3 and the auxiliary roller 5. Accordingly, even when an auxiliary roller 5 the frictional force between the sheet P ₁ is smaller as the resin, feeding the sheet P ₁ to be reliably supplied to between the pickup roller 3 and the auxiliary roller 5,
Without hindering the progress of the sheet P ₁ to be supplied, it is possible to prevent the double feeding of the sheet.

(Embodiment 2)
In the sheet supply apparatus according to the second embodiment of the present invention, the material of the auxiliary roller 5 according to the first embodiment is rubber instead of resin. In addition, the recessed part 5a and the convex part 5b and the coil spring 9 of the auxiliary roller 5 in 1st Embodiment are abolished.

In such a configuration, since the frictional force between the auxiliary roller 5 and the sheet P ₁ becomes large, even if the concave portion 5 a and the convex portion 5 b are eliminated, the sheet P ₁ is reliably attached to the pickup roller 3 and the auxiliary roller by this frictional force. 5 can be sent between.

In this case, the auxiliary roller 5 is continued to rotate by frictional force between the sheet P ₁ is the pickup roller 3 to be supplied to the sheet P ₁ be sandwiched between the auxiliary roller 5 and the auxiliary roller 5, a sheet When P ₁ reaches the nip portion (see FIG. 7) between the pickup roller 3 and the separation pad 4, the rotation stops and the progress of the sheets P _{2 to} P ₅ under the sheet P ₁ to be supplied is blocked by the frictional force. To do. As a result, it is possible to prevent double feeding of sheets without hindering the progress of the sheet P ₁ to be supplied.

  The sheet supply apparatus according to the present invention is useful as an apparatus for supplying single sheets such as paper and OHP (over head projector) sheets one by one in a printing apparatus such as a facsimile, a printer, and a copying machine. In particular, it is suitable as a sheet supply apparatus that prevents double feeding of sheets without hindering the progress of sheets such as recording paper to be supplied.

1 is a perspective view of a sheet supply device provided in a printing apparatus according to a first embodiment of the present invention. FIG. 1 is a perspective view of a sheet supply apparatus in which the sheet supply roller of FIG. 1 is omitted. AA line sectional view of FIG. BB sectional view of FIG. Exploded view of auxiliary roller and auxiliary roller holder Expanded sectional view of the auxiliary roller Sectional drawing which shows the nip part of the pick-up roller and separation pad of the sheet supply apparatus in the 2nd Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet supply apparatus 2 Sheet supply path 3 Pickup roller 4 Separation pad 5 Auxiliary roller 5a Concave part 5b Convex part 6 Control member 7 Separation pad holder 7a Rotating shaft 7b Spring 8 Auxiliary roller holder 8a Support shaft 8b Rotating shaft 8c Spring 9 Coil spring

Claims (7)

A sheet holding unit for holding a plurality of sheets;
A sheet supply roller for feeding the sheet of the sheet holding unit through a sheet supply path;
A separation pad biased against the sheet supply roller;
A sheet feeding apparatus comprising: an auxiliary roller that is disposed to face the sheet feeding roller across the sheet feeding path and rotates by a frictional force generated by contact with the sheet feeding roller. The sheet supply according to claim 1, further comprising a regulating member that regulates a width of the sheet supply path so that only one uppermost sheet of the sheet holding unit is in contact with the sheet supply roller. apparatus. The sheet feeding apparatus according to claim 1, further comprising a load member that applies a load to the rotation of the auxiliary roller. The sheet feeding device according to claim 1, wherein the auxiliary roller is made of resin. The sheet feeding apparatus according to claim 4, wherein the surface of the auxiliary roller is provided with unevenness. The sheet feeding apparatus according to claim 1, wherein the auxiliary roller is made of rubber. A printing apparatus comprising the sheet supply apparatus according to claim 1.

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