JP2958400B2 - Sheet feeding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sheet feeding apparatus that separates and feeds a plurality of stacked sheets one by one.

2. Description of the Related Art In a recording apparatus such as a printer or a copying machine, or a document reading apparatus, a feeding apparatus for separating and feeding one sheet at a time from a plurality of stacked sheets (recording paper, document, etc.) ( Many use a so-called cut sheet feeder).

There are various types of sheet separating mechanisms of the feeding device, and a representative one of them uses a separating claw. As shown in FIG. 5, this is achieved by pressing both sides of the front end of the sheet 51 stacked on the stacking plate 50 in the feeding direction with separation claws 52 and pressing the stacking plate 50 with a pressing spring 53 to form the uppermost sheet 51. Is pressed against the feed roller 54, and when the feed roller applies a feeding force to the uppermost sheet, the uppermost sheet 51
A loop is formed between the separation claw 52 and the feeding roller 54, and the separation claw 52 gets over the separation claw 52 by "strength" and is separated and fed one by one.

In the case where the feeding mechanism is used in a recording apparatus, the rear end of the sheet 51 is fed from a feeding roller 54 after the normal recording is started.
You will come out of. Therefore, when the end of the sheet 51 comes off the feeding roller 54, the sheet carrying load fluctuates,
The feed pitch may be disturbed. Also, in the case of a word processor or the like, the sheet may be reversely fed.However, when the sheet which has once started to be fed is reversely fed, the rear end of the sheet hits the stopped feeding roller 54 and a jam occurs. There is.

Therefore, as shown in FIG. 5, the feed roller 54 is formed in an arc shape having an arc portion 54a that presses the sheet 51 and a chord portion 54b that does not contact the sheet 51, and the sheet 51 is unloaded to the transport roller 55 by the arc portion 54a. After that, the roller 54 is rotated by a predetermined amount so that the chord portion 54b faces the sheet 51.

<Problems to be Solved by the Invention> However, in the feeding mechanism, since the separation claw 52 and the feeding roller 54 are located at both ends in the sheet width direction, the separation claw is required when the wide sheet 51 is fed. 52 and the feed roller 54 are largely separated from each other to the left and right, and a loop formed on the sheet 51 is formed at both ends of the sheet, but it is not clean at the center and it is folded in the opposite direction and smoothly passes over the separation claw 52. May not be possible.

Further, when the chord portion 54b of the feed roller 54 is opposed to the sheet 51, the roller 54 does not contact the sheet 51, so that there is a problem that it is difficult to hold the stacked sheets 51.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a sheet feeding apparatus which can feed a wide sheet smoothly and can surely hold a sheet.

<Means for Solving the Problems> A representative means of the present invention for solving the above problems is:
Sheet stacking means for stacking and supporting sheets, a guide member movably provided in a width direction of a plurality of sheets stacked on the sheet stacking means, and guiding a side end of the sheet, and movement of the guide member A separating claw for separating the normal sheet by pressing the front end portions on both sides of the sheet on the uppermost layer, separating means for separating the thick sheet, and a shaft to which the driving force is transmitted. An arc portion that is slidably supported by the shaft and that can be arbitrarily set on the shaft in accordance with the position of the guide member, and an arc portion that contacts the sheet, and a chord portion that can be separated from the sheet. A pair of feeding rollers for applying a feeding force to the uppermost sheet by the arc portion, and slidably supported on the shaft between the pair of feeding rollers, and optionally on the shaft. Position can be set There is a circular auxiliary member formed with a diameter larger than the diameter of the chord of the feed roller, and a high friction member provided at a position facing the feed roller in the sheet stacking means, When the normal sheet is fed and separated by the separation claw, the auxiliary member can be slid and set at the center between the feeding rollers, and the thick sheet is fed to separate the thick sheet. In the case where the auxiliary member is separated, the auxiliary member is configured to be slidable and set at a position facing the high friction member near the feeding roller.

<Operation> In the above-described means, the sheets are separated and fed one by one by the rotation of the feeding roller and the action of the separation claw. At this time, when feeding a normal sheet, the auxiliary member is slid and set at the center between the feeding rollers, so that even in the case of a wide sheet, the center portion is pressed by the auxiliary member, so the sheet loop is formed. It can be clean even in the center in the width direction, and smooth separation and feeding is performed.

When the thick sheet is separated and fed, the auxiliary member is slid and set at a position in the vicinity of the feeding roller to face the high friction member, thereby enabling stable sheet feeding.

In addition, by making the diameter of the auxiliary member larger than the diameter of the chord portion of the feeding roller, even if the chord portion is opposed to the sheet, the sheet is securely held in contact with the auxiliary member. become.

<Embodiment> Next, an embodiment of a recording apparatus to which the above-described means is applied will be described.

1 and 2 are perspective explanatory views of a sheet feeding apparatus according to the present embodiment.

First, the overall schematic structure will be described. A mounting plate 3 urged upward by a pressing spring 2 is accommodated in a frame 1, and a large number of recording sheets 4 are stacked on the mounting plate 3. When the feed roller 5 is rotated in the direction of the arrow in FIG. 1, the recording sheet 4 of the uppermost layer is separated by the separation claw 6 and the transfer roller 7 is rotated.
It is configured to be fed to Further, at the time of the feeding, the recording sheet 4 is attached to a shaft 8 on which the feeding roller 5 is mounted.
The sheet is fed while being pressed by an auxiliary roller 9 mounted coaxially.

Next, the configuration of each part will be specifically described. The frame 1 is divided into a left half 1a and a right half 1b, and the frame 1 is adjusted along the entire width direction of the sheet by sliding them along the axis 8. Has become possible. The placing plate 3 is also housed separately in the left and right frame bodies 1a and 1b, and the respective placing plates 3 are urged upward by the pressing springs 2, whereby the recording sheets 4 stacked on the placing plate 3 are moved upward. The upper layer is configured to be in pressure contact with the feed roller 5.

As shown in FIG. 1, ordinary side guides 10, which are guide members for guiding both side ends of the ordinary sheet 4, are provided on the outer wall portions of the left and right frames 1a and 1b. As shown in FIG. 2, when a thick sheet 4 such as a postcard or a drawing paper is fed, a thick guide 11 for guiding both sides of the thick sheet 4 is provided at a predetermined position of the placing plate 3 so as to be able to protrude and retract. Have been. The thick guide 11 is configured to be capable of standing up and flattening with respect to the mounting plate 3, and has a structure that can be stored in the bottom surface by flattening.

A high-friction sheet 12 as a high-friction member made of, for example, clarino, cork, or the like is fitted in a predetermined position of the placing plate 3, that is, inside the thick guide 11 in this embodiment.

Next, as shown in FIG. 1, the feed roller 5 has a protrusion 8a of the roller 5 fitted into a groove 8a formed on the shaft 8 to which a driving force from a motor (not shown) is transmitted, and is integrated with the shaft 8. The recording sheet 4 is attached so as to be slidable in the thrust direction, and can be set at an appropriate position according to the width of the recording sheet 4 to be set.

The outer periphery of the feed roller 5 is made of a high friction material such as rubber, and as shown in FIGS. 3 (A) and 3 (B),
An arc portion 5b having a radius l ₁ and a chord portion having a diameter l ₂ shorter than the diameter of the chord portion 5b
When the feed roller 5 rotates, the arc portion 5b is pressed against the recording sheet 4 and the chord portion 5c is separated from the recording sheet 4.

Next, the separating claw 6 will be described. In this embodiment, the separating claw 6 is formed integrally with the frame 1, and each of the separating claw 6 a presses a corner of the front end of the recording sheet 4, and a protrusion which abuts the leading end of the sheet. It is configured in a shape having a contact portion 6b, and the claw portion
A slit 6c is formed between 6a and the abutting portion 6b. The slit 6c is formed to approximately half the width of the claw portion 6a. As shown in FIG. 2, the sheet is formed by aligning both ends of the thick recording sheet 4 with the thick guide 11 to form a sheet. The front end corner of the sheet 4 is pressed by the claw portion 6a of the separation claw 6, but the front end of the sheet 4 does not abut against the abutment portion 6b, and can smoothly go straight in the feeding direction through the slit 6c. The dimensions are configured.

Further the slit 6c, as shown in FIG. 4, the projection dimension L ₁ traveling direction of the sheet 4 to be fed, the L ₁ and different projection sized to be formed in a direction, i.e. the claw portion 6a and the abutting portion has a distance L ₂ between 6b, the L ₂ is formed to be larger than L _1. Further projection dimension L ₁ of the sheet travel direction is smaller than the thickness L ₃ of the thick sheet to be fed, the projection dimension L ₂ in the vertical direction of the claw portion 6a is greater than the thickness L ₃ of the thick sheet It is set as follows.

Next, the auxiliary roller 6 is composed of two circular rollers made of a low-friction material, for example, polyacetal, and is slidable in the thrust direction with respect to the same shaft 8 as the feed roller 5 so that it can be easily rotated. Installed. Also the roller diameter l _0, as shown in FIG. 3, smaller than the diameter l ₁ of the arc portion 5b of the feed roller 5 is larger than the diameter l ₂ of the chords 5c (l _1> l _0> l ₂ ) It is configured to have a dimensional shape.

Therefore, the auxiliary roller 9 is separated from the recording sheet 4 when the arc portion 5b of the feeding roller 5 is pressed against the recording sheet 4,
When the chord portion 5c of the feed roller 5 faces the recording sheet 4, the chord portion 5c contacts the sheet 4.

Next, the recording sheet 4 is formed by the apparatus configured as described above.
The operation when feeding is described.

First, when a wide normal sheet is fed, the thick guide 11 is flattened as shown in FIG.
Is mounted on the mounting plate 3, the two feeding rollers 5 are set near both ends in the width direction of the sheet 4, and the auxiliary roller 9 is set substantially near the center. When the shaft 8 is rotated in the direction of the arrow in this state, the arc portion 5b of the feed roller 5 is pressed against the sheet 4 to rotate, and a propulsive force is applied to the uppermost sheet 4.
At this time, a loop is formed between the separation claw 6 and the feeding roller 5 because the leading end of the sheet 4 abuts against the abutting portion 6c of the separation claw 6. Even if the recording sheet 4 is wide, the auxiliary roller 9 guides the formation of the loop near the center in the width direction of the recording sheet 4, and a uniform loop is formed as a whole. When a certain amount of loop is formed, the leading end of the sheet is separated from the separation claw 6 due to the "strength" of the sheet 4, and one recording sheet 4 of the uppermost layer is separated and fed. As a result, the leading edge of the fed sheet abuts on the nip portion between the transport roller 7 and the pinch roller 7a to form an overall uniform loop.

Even when the wide recording sheet 4 is separated and fed as described above, a uniform loop is formed as a whole, so that the sheet 4 is separated and the conveyance roller 7 and the pinch roller 7a are pressed against the nip portion to form a loop. Is performed smoothly, and wrinkles and skewing are prevented.

Even after the recording sheet 4 is fed, even if the feeding roller 5 is separated from the recording sheet 4 (the state in which the string portion 5c faces the recording sheet 4), since the auxiliary roller 9 is in contact with the recording sheet 4, The sheet 4 is securely held.
Further, since the auxiliary roller 9 is made of a low-friction material, the load fluctuation that occurs when the trailing edge of the sheet escapes from the auxiliary roller 9 is extremely small, so that the line feed pitch is not disturbed.

Next, the case of feeding a thick sheet will be described.
In this case, the thick guide 11 is erected as shown in FIG. 2 and both ends of the thick recording sheet 4 are guided by the guide 11. Further, the feed roller 5 and the auxiliary roller 9 are slid so as to be located near both ends in the width direction of the recording sheet 4, respectively.

When the shaft 8 is rotated in the above state, a propulsive force is applied to the recording sheet 4 by the arc portion 5b of the feeding roller 5 as in the case of a normal sheet. At this time, since the size of the separation claw 6 is set as described above, one recording sheet 4 of the uppermost layer is formed.
Lightly touches the upper end of the abutting portion 6b, and only one of the uppermost layers is separated and sent to the transport roller 7 so as to escape above the abutting portion 6b (see FIG. 3 (A)). .

When the thick recording sheet 4 reaches the transport roller 7 as described above, the sheet 4 is transported by a motor (not shown) and a pinch pressed against the roller 7 as shown in FIG. The sheet is conveyed to a recording unit or the like by the roller 7a. At this time, the chord portion 5c of the feeding roller 5 faces the recording sheet 4 and is separated from the recording sheet 4, but the low friction auxiliary roller 9 is in pressure contact with the recording sheet 4.
Therefore, as described above, even if the thick sheets 4 are sequentially separated and fed, and the remaining two sheets are left, the lowermost layer sheet 4 is pressed against the high friction sheet 12 attached to the mounting plate 3 and its friction is increased. Since the force acts, so-called last double feed is prevented.

By providing the auxiliary roller 9 in addition to the feed roller 5 as described above, the wide sheet 4 can be separated and fed smoothly, and the last double feed of a thick sheet can be prevented.

In the above embodiment, two auxiliary rollers 9 are provided. However, one auxiliary roller may be provided at the center in the sheet width direction. They may be arranged evenly between them.

When the thick sheet is limited to a relatively narrow one such as a postcard, one auxiliary roller having a length substantially equal to the dimension between the two feeding rollers 5 is provided. Is also good.

Further, in the above-described embodiment, the example in which the separation claw 6 is formed integrally with the frame body 1 is shown. However, only the claw part 6a is formed integrally with the frame body 1, and the claw part 6a and the abutting member formed as a separate member The portion 6b may be attached to the frame 1 with screws or the like. In this way, it is difficult to obtain precision with the integrated bending
Accuracy can be easily increased by measuring the size and shape of 6c with the positional accuracy of two parts.

In the above-described embodiment, the example in which the thick guide 11 is provided on the loading plate 3 is shown. However, the loading plate for loading the thick sheet is formed separately from the loading plate for loading the normal sheet, and the sheet side guide is provided on each loading plate. May be formed. In this case, when feeding a normal sheet, the stacking plate for the thick sheet is removed and used, and when feeding a thick sheet, the stacking plate is fitted on the mounting plate for the normal sheet and used after positioning. What should I do?

<Effect of the Invention> As described above, according to the present invention, when a normal sheet is fed, the auxiliary member is slid so that the sheet can be set at the center between the feeding rollers. Can be held down by the auxiliary member, and the sheet loop can be cleaned even in the center portion in the width direction, so that smooth separation and feeding can be performed.

Also, when separating and feeding a thick sheet, the auxiliary member is slid and set at a position facing the high friction member in the vicinity of the feeding roller, thereby reliably preventing the last double feeding of the thick sheet, Stable sheet feeding becomes possible.

Further, even when the feeding roller is separated from the sheet, the auxiliary member can be securely held in contact with the sheet.

In addition, by appropriately changing the position of the auxiliary member between the feeding members, stable sheet feeding can be performed regardless of the sheet thickness or the sheet size.

[Brief description of the drawings]

1 and 2 are perspective explanatory views of a sheet feeding device according to an embodiment of the present invention, and FIGS. 3A and 3B are views for explaining the relationship between a feeding roller and an auxiliary roller during sheet feeding. FIG. 4 is an explanatory view of a separation claw, and FIG. 5 is an explanatory view of a conventional technique. 1 is a frame, 1a is a left half, 1b is a right half, 2 is a pressing spring, 3
Is a mounting plate, 4 is a recording sheet, 5 is a feeding roller, 5a is a protrusion, 5b is an arc, 5c is a chord, 6 is a separation claw, 6a is a claw, 6b is a striking part, and 6c is a slit. , 7 are conveying rollers, 8 is a shaft, 8a is a groove, 9 is an auxiliary roller, 10 is a normal guide, 11 is a thick guide, and 12 is a high friction sheet.

Continuation of the front page (56) References JP-A-55-74929 (JP, A) JP-A-58-172131 (JP, A) JP-A-61-282228 (JP, A) Jpn. , U) Japanese Utility Model Showa 60-93638 (JP, U) Japanese Utility Model Showa 61-122230 (JP, U) Japanese Patent Publication No. 55-11098 (JP, B2)

Claims (2)

(57) [Claims] 1. A sheet stacking means for stacking and supporting sheets, a guide member movably provided in a width direction of a plurality of sheets stacked on the sheet stacking means, and guiding a side end of the sheet; A separating claw for moving along with the movement of the guide member and pressing the front end portions on both sides of the sheet on the uppermost layer to separate a normal sheet; a separating means for thick for separating a thick sheet; A shaft to be transmitted, slidably supported by the shaft, provided so that the position on the shaft can be set arbitrarily according to the position of the guide member, and an arc portion in contact with the sheet, and separated from the sheet A pair of feeding rollers for applying a feeding force to the uppermost sheet by the arc portion, and slidably supported on the shaft between the pair of feeding rollers, Optionally on the axis The position can be set, a circular auxiliary member formed with a diameter larger than the diameter of the chord of the feeding roller, and a high friction member provided at a position facing the feeding roller in the sheet stacking means. When the normal sheet is fed and separated by the separation claw, the auxiliary member can be slid and set at the center between the feeding rollers, and the thick sheet is fed. A sheet feeding device, wherein when the sheet is separated by the thick separating means, the auxiliary member is slidable and set at a position facing the high friction member in the vicinity of the feeding roller. . 2. A sheet feeding apparatus according to claim 1, wherein said thick separating means is a slit for separating one thick sheet.