JPH0761816B2 - Paper feeder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for feeding cut sheets one by one to various printers and copying machines.

(Prior Art) Conventionally, for example, in a printer, in order to reliably feed the cut sheet toward the platen by the rotation of the feed roller, the cut sheet is pressed so as to contact the feed roller. When the cut sheet is fed to the platen by the rotation of the feed roller, the cut sheet is fed to a predetermined printing position by the rotation of the platen after the rotation of the feed roller is stopped.

(Problems to be Solved by the Invention) In the above-mentioned conventional apparatus, the cut sheet is pressed against the outer peripheral surface of the feed roller by the pressing body even after the rotation of the feed roller is stopped. Therefore, when the platen is fed with the cut sheet, a large frictional force is generated between the feed roller and the cut sheet. Therefore, there is a problem in that the platen must be driven by a drive motor having a large capacity, and the feeding force of the cut sheet by the platen must be set larger than the frictional force by a predetermined amount.

Also, in order to reduce the frictional force generated between the feed roller and the cut sheet, a clutch mechanism is interposed between the feed roller and its driving shaft, and the platen is cut by the platen after the drive shaft is stopped. It is conceivable that the feed roller can be freely moved with respect to the drive shaft by turning off the clutch mechanism at the time of feeding. However, if a clutch mechanism is to be interposed between the feed roller and its drive shaft, it becomes difficult to secure a space for disposing the clutch mechanism, and the structure becomes complicated and the cost increases. .

(Means for Solving Problems) In order to solve the above-mentioned conventional problems, the present invention supports a supporting frame slidably in the width direction of the cut sheet, and A pair of left and right paper receiving plates that are stacked and held, and a feed roller that is disposed at the base of each of the paper receiving plates and that feeds the single-cut sheets to the platen one by one,
A hollow boss portion provided in the center of each feed roller, a drive shaft fitted in the hollow portion of each boss portion, and a drive shaft for transmitting the rotation of the drive shaft to each feed roller. A rotation transmitting member that is provided inside the hollow portion of the boss portion and that slidably engages with the drive shaft, and a rotation transmitting member that is respectively disposed at the base portion of each of the paper receiving plates and that allows the boss portion of each of the feed rollers to rotate. Support
Also, a bearing member that movably supports the feed rollers as a unit as the paper receiving plates move in the axial direction of the drive shaft, and a swing member provided on each side of the paper receiving plates. Possible support arms and the lower part of each of the support arms are urged in one direction by an elastic body, so that the support arms are urged by the lower part of the support arm and the cut sheet is pressed against the feed roller. The feed roller is formed in a substantially half-moon shape when viewed in the drive axis direction, and the single-cut sheet is formed by friction between the substantially half-moon arc portion of the feed roller and the single-cut sheet. A predetermined amount is conveyed in the platen direction, and the pressing body is retracted against the urging force of the elastic body within the rotation angle range of the drive shaft such that the non-arcuate portion of the feed roller faces the cut sheet. Keep the paper away from the feed rollers. For this purpose, each boss is formed in a circular arc in the rotation angle range of the drive shaft so that a concentric circle with the rotation center of the drive shaft is drawn and the non-arc-shaped part of the feed roller faces the cut sheet. And the interlocking pawls engaging with the respective retreat cams are provided in the support arm in the rotation angle range of the drive shaft such that the non-arcuate portions of the respective feed rollers face the single-cut sheets. It is configured to be provided in each.

(Operation) In the paper feeding device of the present invention having the above configuration, the cut sheets are held in a stacked manner by the pair of left and right paper receiving plates, and the single sheet is held by the bearing member provided at the base of each paper receiving plate. The boss of the feed roller that feeds the form paper is rotatably supported.
By the rotation transmission member provided in the hollow portion of the boss,
The rotation of the drive shaft is transmitted to the feed roller. Here, during one rotation of the drive shaft, the uppermost cut sheets stacked on the pair of left and right paper receiving plates are fed by a predetermined amount by the substantially half-moon shaped arcuate portion of the feed roller.

After a predetermined amount of paper has been fed by the substantially half-moon shaped arcuate portion of the feed roller, in the rotation range of the drive shaft where the non-circular arcuate portion of the feed roller faces the cut sheet, the retreat provided on the boss portion The cam engages with the interlocking claw of the support arm provided on the side portion of the paper receiving plate to resist the pressing force of the elastic member that biases the support arm from the pressing body that presses the cut sheet. By retracting, the frictional force between the feed roller and the cut sheet is eliminated.

Further, since the boss portion of the feed roller is pivotally supported by the bearing member arranged at the base of each paper receiving plate, each paper receiving plate is made to have the same width direction as that of the single-cut sheet in correspondence with the single-cut sheets having different paper widths. Even when the movement is adjusted in the axial direction of the drive shaft, the paper receiving plate and the feed roller can move together in the axial direction of the drive shaft.

Therefore, the backward cam of the boss portion of the feed roller and the interlocking claw of the support arm assembled to the paper receiving plate do not cause a relative displacement in the axial direction of the drive shaft.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, which shows the main part of the printer in a side cross-section, a platen shaft 2 rotatably driven in a predetermined direction (clockwise in the figure) by a drive mechanism is provided between the left and right side walls located at the rear of the printer body 1. It is arranged. This platen shaft 2
A platen 3 that rotates integrally with the same axis is mounted around the axis of. A carriage 5 having a print head 4 is arranged in front of the platen 3 so as to be capable of reciprocating along the platen 3.

A predetermined number of feed rollers 6, 7, 8 which are in pressure contact with the outer peripheral surface of the platen 3 are rotatably arranged on the rear side and the lower part of the platen 3. The feed rollers 6, 7, 8 are driven to rotate in accordance with the rotation of the platen 3 to perform a paper feeding operation.

Further, a guide plate 9 which constitutes a paper guide passage 11 is arranged along the lower peripheral surface of the platen 3. Further, a paper bail 10 facing the outer peripheral surface of the platen 3 so as to be able to come into contact with and separate from the outer peripheral surface of the platen 3 is disposed on the upper front side of the platen 3.

On the outer surface of the rear wall of the printer body 1, there is provided a continuous paper feed mechanism including a pair of left and right feed sprockets 12 for sending continuous paper toward the entrance of the paper guide passage 11.

A single-cut sheet P is placed on the platen 3 above the rear of the printer body 1.
The paper feeding device 13 for feeding to the above is detachably mounted as one unit. In this paper feeding device 13, the rear wall of the support frame 14 that is installed between the left and right side frames
A paper holder 15 for stacking and holding a large number of cut sheets is arranged on 14a. The paper hodder 15 is composed of left and right paper receiving plates 16 slidably supported by the rear wall 14a of the support frame 14 and an intermediate paper receiving plate so that it can correspond to cut sheets of different sizes. It has become.

A pair of support arms 17 are provided at the upper ends of the paper holders 15 on the left and right sides of the paper receiving plates 16 so as to be swingable around pins 18 as fulcrums. At the lower part between the both support arms 17, the cut sheet P can be moved forward and backward with respect to the paper receiving surface of each paper receiving plate 16 of the paper holder 15 and is always projected from the paper receiving surface by the spring 19. Feed roller described below
A pressing body 20 that presses the feeding surface 22a of the pressing member 21 is provided.

A drive shaft 24 is rotatably disposed between the left and right side frames on the paper feeding side of the paper holder 15. The drive shaft 24 is rotated by a motor capable of rotating in the normal and reverse directions (for example, a stepping motor) via a gear train or the like. Around the axis of the drive shaft 24, the cut sheet paper P of the paper holder 15 is
A pair of left and right feed rollers 21 for feeding the sheets to the platen 3 one by one
However, the boss portion 23 is fitted so as to be rotatable integrally with the drive shaft 24 and slidable in the axial direction of the drive shaft 24.

The outer circumference of each feed roller 21 is a rubber layer 22 made of a high friction material.
And an arc-shaped feed surface 22a which is formed by the above-mentioned paper holder 15 and contacts the uppermost cut sheet P of the paper holder 15 to feed the sheet.
And the non-feeding surface 22b forming the arcuate chord of the feeding surface 22a are formed in a substantially half-moon shape. Then, during one rotation of the drive shaft 24, the feeding surface 22a of each feeding roller 21 feeds the uppermost cut sheet P to between the platen 3 and the feed roller 6 in contact with the outer peripheral surface of the rear portion. Has become.

A retreating cam 25 is arranged around the drive shaft 24.
This reversing cam 25 is a feed roller in one rotation of the drive shaft 24.
The pressing body 20 is provided with a spring 19 to the position where the cut sheet P is separated from the outer circumference of the feed roller 21 as the drive shaft 24 continues to be rotated after the cut sheet P is fed by the feed surface 22a of 21. Retreat against the forces. In this embodiment, as shown in FIGS. 1 and 2, a disc-shaped cam plate 35 is integrally formed on the outer end portion of the boss portion 23 of each feed roller 21. A retreating cam 25 that is concentric with the drive shaft 24 and has an arc shape with a predetermined angle is formed on one side surface of the cam plate 35.

Further, at a predetermined position of the support arm 17 of the pressing body 20, an interlocking claw 26 that engages with the one end surface 25a of the retreating cam 25 at the base of the pin is formed at the base portion at substantially the same time when the paper feeding by the feeding surface 22a of the feeding roller 21 is completed. It is mounted so that it can rotate around 36 as a fulcrum.

The tip surface 26a of the interlocking pawl 26 is formed in a semicircular shape so as to be movable from the one end surface 25a of the retreat cam 25 along the arc surface 25b of the retreat cam 25, and is always formed by a spring (not shown). It is urged counterclockwise and is held by the stopper means at a position facing the one end surface 25a of the retreat cam 25 so as to be engageable with it, as shown in FIG. That is,
Of the one rotation of the drive shaft 24 in the feeding direction, substantially at the same time as the completion of the paper feeding by the feeding surface 22a of the feeding roller 21, the reversing cam 2
The positions where the retreat cam 25 and the interlocking pawl 26 are arranged are set so that the one end surface 25a of 5 and the tip end surface 26a of the interlocking pawl 26 engage with each other. Further, after the paper feed by the feed surface 22a of the feed roller 21 is completed, while the drive shaft 24 is rotated to the original position, the arc surface 25b of the retreat cam 25 and the tip surface 26a of the interlocking claw 26 are formed.
The arc surface 25 of the retreat cam 25 allows the pressing body 20 to retreat against the urging force of the spring 19 from the outer periphery of the feed roller 21 to the position where the cut sheet P is separated by a predetermined gap.
The radius of b and the length of the interlocking claw 26 are appropriately set.
Further, while the drive shaft 24 completes one rotation in the feed direction, and thereafter the platen 3 is rotated to feed the cut sheet P to the print position, the pressing body 20 resists the biasing force of the spring 19 and moves to the retracted position. The length of the arcuate surface 25b of the retreating cam 25 is appropriately set so that it can be held at.

In the above embodiment, the drive shaft 24 is reversed by turning on the start switch, and the feed surface 22a of the feed roller 21 is turned on.
Is set between the drive shaft 24 and the side frame by a cam and a stopper (not shown) so that the feed roller 21 is positioned at a regular rotation start position of the paper holder 15 facing the cut sheet P. ) Is provided. And
When the drive shaft 24 is reversed, the interlocking pawl 26 is rotated against the biasing force of the spring so that the retracting cam 25 and the interlocking pawl 26 do not get caught.

Further, in this embodiment, at the other end of the boss portion 23 of each feed roller 21, in addition to the cam plate 35, projections 23a are provided at predetermined intervals in the axial direction with the cam plate 35, and the paper holder 15 is provided between them. The semicircular recesses 16b provided at the front lower ends of the outer sides of the left and right paper receiving plates 16 are rotatably coupled to each other, and by sliding the left and right paper receiving plates 16, each feed roller 21 is moved. It is adapted to be linked in the axial direction of the drive shaft 24. Further, at the initial stage of paper feeding by the respective feed rollers 21, the front (lower) corners of the uppermost cut sheets P of the paper holder 15 are locked at the lower end corners of the left and right paper receiving plates 16 by buckling. It is detached from the piece 16a, so that the sheets are separated one by one and the sheets are fed. A notch-shaped relief portion 26 is formed at a predetermined position of the boss portion 23 of each feed roller 21 so as not to interfere with the buckling action of the cut sheet P, as shown in FIG. ing.

As shown in FIG. 1, a feed roller cover 27 and a discharge roller cover 28 are arranged side by side in the front and back at the front part between the left and right side frames. Further, between the front wall of the support frame 14 and the feed roller cover 27, there is formed a feed guide path 29 for feeding and guiding the cut paper P of the paper holder 15 toward the platen 3, and the feed roller cover 27 and the discharge. An insertion guide path 30 is formed between the roller cover 28 and the roller cover 28 to guide the single-cut sheet manually fed toward the platen 3. Further, a paper discharge port 32 is formed between the discharge roller cover 28 and the rear end surface of the top cover plate 31 of the printer body 1.
The discharge roller cover 28 is provided on the front part between the left and right side frames.
The discharge roller 33, which is partially exposed and covered by the above, is rotatably arranged. Then, by the rotation operation of the discharge roller 33, the paper discharged from the paper discharge port 32 is discharged to the stacker 34 arranged on the upper cover plate 31 of the printer body 1.

This embodiment is constructed as described above.

Therefore, as shown in FIG. 1, from the position where the non-feeding surface 22b of each feed roller 21 faces the cut sheet P of the paper holder 15, the feed roller 21 makes one rotation by the drive shaft 24. First, the feed surface 22a of each feed roller 21
Thus, the uppermost cut sheet P of the paper holder 15 is sent out between the platen 3 and the feed roller 6 which is in contact with the outer peripheral surface of the rear part of the paper holder 15 through the feed guide path 29.

When the feeding of the cut sheet P by the feeding surface 22a of each feeding roller 21 is completed, at the same time as this, one end surface 25a of the retreating cam 25 is formed.
, Engages with the tip surface 26a of the interlocking pawl 26, as shown in FIG. Then, as the drive shaft 24 continues to rotate in the remaining range, the retracting cam 25 and the interlocking pawl 26 cooperate with each other to press the body.
20 is sequentially retracted against the biasing force of the spring 19.

When the pressing body 20 is retracted to a predetermined position and the cut sheet P is separated from the non-feed surface 22b of the feed roller 21 with a predetermined gap, the interlocking claw 26 is moved to the arc surface 25b of the retreat cam 25.
Engage at the tip surface 26a thereof. by this,
The pressing body 20 is held in the retracted position, and in this state, the drive shaft 24 rotates by the remaining range angle and stops. Even when the drive shaft 24 stops rotating, the pressing body 20 is held in the retracted position by the engagement between the arcuate surface 25b of the retractable cam 25 and the tip surface 26a of the interlocking claw 26 (see FIG. 1). .

When the drive shaft 24 and the feed roller 21 make one rotation and stop, the platen 3 is rotated and the cut sheet P is fed to the printing position. When the cut sheet P is fed by the rotation of the platen 3, the pressing member 20 is held in the retracted position against the urging force of the spring 19 by the cooperation of the retracting cam 25 and the interlocking claw 26, and the feeding roller The cut sheet P is held apart from the sheet 21 with a predetermined gap. Therefore, the frictional force between the feed roller 21 and the single-cut sheet P at the time of feeding the single-cut sheet P by the platen 3 is eliminated, and the single-cut sheet P is smoothly fed to a predetermined printing position.

During the feeding of the next cut sheet, the feed roller 21 is rotated by a predetermined angle together with the drive shaft 24, and the interlocking pawl 26 is moved from the arc surface 25 of the retreating cam 25 while the rotation side of the feed surface 22a faces the cut sheet P. Come off. Then, the pressing body 20 is pushed out by the urging force of the spring 19, whereby the cut sheet P of the paper holder 15 is pressed toward the feed roller 21. After that, the single-cut sheet P is sent to the platen 3 as described above.

(Effects of the Invention) As described above, according to the present invention, by the engagement of the backward movement cam and the interlocking claw with the rotation of the drive shaft following the feeding of a predetermined amount of paper by the feeding roller, By retracting the pressing body to the position where the cut sheets are separated from each other, the frictional force between the feed roller and the cut sheets can be eliminated. Therefore, even if the driving motor of the platen is a small motor having a small capacity and the feeding force of the cut sheet by the platen is set as small as possible, the feeding action of the cut sheet can be sufficiently performed.

Moreover, unlike a structure in which a clutch mechanism is interposed between the drive shaft and the feed roller, the structure can be extremely simple and can be provided at low cost.

Furthermore, even when a pair of paper receiving plates are moved and adjusted in the axial direction of the drive shaft in the same direction as the width direction of the cut sheets corresponding to the cut sheets of different paper widths, the movement of these paper receiving plates is integrated with each other. Since the feed roller moves in the axial direction of the drive shaft, the retreat cam of the boss portion of the feed roller and the interlocking claw of the support arm assembled to the paper receiving plate are relatively displaced in the axial direction of the drive shaft. It is possible to prevent malfunctions and eliminate malfunctions due to axial displacement.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a side sectional view showing an essential part of a printer, FIG. 2 is a perspective view showing an essential part of a sheet feeding device, and FIG. FIG. 4 is a side sectional view showing a state immediately after the start of feeding, and FIG. 4 is a side sectional view showing a state after the feeding of the cut sheet is completed. 3 …… Platen 13 …… Paper feeder 15 …… Paper holder 20 …… Pressing body 21 …… Feed roller 24 …… Drive shaft 25 …… Reverse cam 26 …… Interlocking pawl

Claims (1)

[Claims] 1. A pair of left and right paper receiving plates, which are slidably supported in a width direction of the cut sheets with respect to a support frame, hold the stacked cut sheets, and a base portion of each of the paper receiving plates. Feed rollers that are respectively provided to feed the single-cut sheets to the platen one by one, hollow boss portions that are respectively provided in the central portions of the respective feed rollers, and are inserted into the hollow portions of the boss portions. A drive shaft, a rotation transmission member that is provided in a hollow portion of each boss portion and that slidably engages with the drive shaft to transmit the rotation of the drive shaft to each feed roller, and each paper receiving plate. Each of which is arranged at the base of each of the feed rollers, rotatably supports the boss portion of each of the feed rollers, and moves the feed rollers as the paper receiving plate moves in the axial direction of the drive shaft. A bearing member that rotatably supports and a rocking member that is disposed on each side of the paper receiving plate. Possible support arms and the lower parts of the respective support arms are urged in one direction by an elastic body, so that the support arms are urged by the lower part and the cut sheet is pressed so as to contact the feed roller. The feed roller is formed in a substantially half-moon shape when viewed in the drive axis direction, and the single-cut sheet is formed by friction between the substantially half-moon arc portion of the feed roller and the single-cut sheet. A predetermined amount is conveyed in the platen direction, and the pressing body is retracted against the urging force of the elastic body in the rotation angle range of the drive shaft such that the non-arcuate portion of the feed roller faces the cut sheet. In order to keep the paper away from the feed roller, a drive shaft is drawn on each of the bosses so that a concentric circle with the center of rotation of the drive shaft is drawn, and the non-arcuate portion of the feed roller faces the single-cut paper. In the rotation angle range of Arc-shaped retreating cams are respectively arranged, and interlocking claws that engage with the retreating cams are provided in a rotation angle range of the drive shaft such that the non-arcuate portion of each of the feed rollers faces the cut sheet. A sheet feeder provided on each of the support arms.