JPH09267944A - Paper supply device and printer which uses it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable paper supply device which can separate various kinds of paper irrespective of its rigidity. SOLUTION: This paper supply device is provided with a hopper 3 which stores paper S in a condition in which the paper S is laminated in layers and a paper supply roller 41 which comes into contact with a surface of the paper S stored in the hopper 3 and sends out the paper S in a predetermined feed direction. In this case, a wall part 5 is provided in an end part in the feed direction of the hopper 3 so that the paper S fed out from the hopper 3 collides against it. An inclined face 51 which is inclined gradually in the feed direction as it leaves the hopper 3 upward and a stopper 61 which can come in and out freely for the inclined face 51 are provided in the wall part 5. The stopper 61 is energized by a spring 62 in the direction in which it protrudes from the inclined face 51. In the case of paper having large rigidity, the stopper 61 is pressed in the inclined face 51 and is separated by the inclined face 51. In the case of paper having small rigidity, paper is separated by overriding the stopper 61.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for feeding sheets stacked in a hopper one by one by a sheet feeding roller and a printing apparatus using the same.

[0002]

2. Description of the Related Art As a paper feeding device used in a printer,
While feeding the topmost sheet of the hopper in a predetermined feeding direction by a sheet feeding roller that comes into contact with the surface of the hopper, the leading end of the sheet to be fed is brought into contact with an inclined surface connected to the hopper, and the bending of the sheet at that time is used. It is known that the uppermost sheet is separated from the sheets below it and supplied to a predetermined position (for example, a printing position) outside the hopper (for example, JP-A-2-132018).
(See Japanese Patent No. 5026042).

[0003]

In this type of apparatus, the paper separation performance is limited by the nature of the inclined surface, such as the gradient and the friction coefficient, and the types of paper that can be applied are limited.
For example, since it is difficult to separate a sheet having low rigidity, it is necessary to increase the slope of the inclined surface to give sufficient bending. However, when a highly rigid sheet such as a postcard or an envelope is abutted against an inclined surface having a large gradient, there is a possibility that the resistance acting on the sheet is too large and the sheet feeding roller may idle.

Therefore, an object of the present invention is to provide a highly reliable sheet feeding device and printing device which can reliably separate various types of sheets regardless of their rigidity.

[0005]

Hereinafter, the present invention will be described with reference to the drawings showing embodiments of the present invention. However, the present invention is not limited to the illustrated embodiment.

According to the first aspect of the present invention, the hopper 3 for accommodating the sheets S in a stacked state, and the sheet feeding roller 41 for coming into contact with the surface of the sheets S accommodated in the hopper 3 and delivering the sheets S in a predetermined feeding direction. And a wall portion 5 is provided at the end of the hopper 3 in the feeding direction so that the sheet S fed from the hopper 3 abuts on the wall portion 5, and the wall portion 5 is fed as it goes away from the hopper 3. Slope 51 that gradually inclines in the direction
And a stopper 61 that can be retracted and retracted with respect to the inclined surface 51, and the stopper 61 is characterized by a sheet feeding device that is biased by a biasing means 62 in a direction projecting from the inclined surface 51. .

According to the invention of claim 1, in addition to the separating action of the sheet S by the inclined surface 51, the separating action by the stopper 61 can be utilized. Moreover, the separating action of the stopper 61 can be variously changed depending on the property of the contact surface 610 of the stopper 61 with respect to the sheet S (for example, the gradient or the friction coefficient) and the force of the biasing means 62 that biases the stopper 61. . The contact surface 610 of the stopper 61 and the inclined surface 51 are given different properties, whereby the range of the paper S that can be handled can be expanded.

According to a second aspect of the present invention, in the sheet feeding device according to the first aspect, the stopper 61 has a rigidity that resists the pushing force of the abutted sheet S and maintains a constant shape. Therefore, as compared with the case where the stopper 61 is made of a flexible material, the separating action of the sheet S by the stopper 61 is stable. The room for selecting the material that can be used for the stopper 61 is also expanded.

According to a third aspect of the invention, in the sheet feeding device of the first aspect, the stopper 61 is used when the rigidity of the sheet S is small.
The biasing means 62 is provided so that the stopper 61 is protruded from the inclined surface 51 and the stopper 61 is depressed below the inclined surface 51 when the rigidity of the sheet S is high. Therefore, when the rigidity of the sheet S is low, the sheets S are separated from each other by the stopper 61, and when the rigidity is high, the sheets S are separated from each other on the inclined surface 51.

According to a fourth aspect of the invention, in the sheet feeding device of the first aspect, the contact surface 610 of the stopper 61 with respect to the sheet S is 610.
However, the inclination is larger than that of the inclined surface 51 in the feeding direction. Therefore, the stopper 61 sufficiently bends and deforms the leading end of the sheet S having low rigidity to promote mutual separation, while the inclined surface 51 having a small inclination causes the resistance of the wall portion 5 against the sheet S having high rigidity. Can be reduced to prevent the paper feed roller 41 from idling.

According to a fifth aspect of the present invention, in the sheet feeding device according to the fourth aspect, the contact surface 610 is provided so as to be substantially perpendicular to the feeding direction or to be inclined to the side opposite to the feeding direction with respect to the right angle position. . Therefore, the contact surface 610 pushes the sheet S back toward the hopper 3, and the uppermost sheet S of the hopper 3 and the sheet S below it can be reliably separated.

According to a sixth aspect of the present invention, in the sheet feeding device according to the first aspect, the contact surface 610B of the stopper 61B (see FIG. 13) with respect to the sheet S is provided with a groove portion 611 extending in the width direction of the sheet S. . Therefore, the leading end of the paper S sent out from the hopper 3 is engaged with the groove 611 to be flexibly deformed, thereby promoting the separation of the paper S from each other.

According to a seventh aspect of the present invention, in the sheet feeding device according to the first aspect, the stopper 61 is provided on the bottom side of the hopper 3 by the rotational movement around the rotation axis set parallel to the width direction of the sheet S. Appears from 51. Therefore, as the force of the sheet S pressing the stopper 61 decreases, the sheet S of the stopper 61 decreases.
The inclination of the contact surface 610 with respect to the sheet S increases, and the leading edge of the sheet S is largely bent accordingly.

According to an eighth aspect of the invention, in the sheet feeding device of the first aspect, the stopper 61C (see FIG. 14) moves in and out of the inclined surface 51 by a linear motion substantially parallel to the feeding direction.
Therefore, even if the stopper 61C is displaced, the gradient of the contact surface 610C with respect to the sheet S is kept substantially constant.

According to a ninth aspect of the present invention, the hopper 3 for accommodating the sheets S in a stacked state, and the sheet feeding roller 41 for abutting the surface of the sheets S accommodated in the hopper 3 and feeding the sheets S in a predetermined feeding direction. And a wall portion 5 is provided at the end of the hopper 3 in the feeding direction so that the paper S delivered from the hopper 3 abuts, and the paper abutted against at least a part of the wall portion 5. A stopper 61 that has a rigidity that maintains a constant shape against the pushing force of S and that is displaceable in the feed direction
Is provided, and the stopper 61 is characterized by a sheet feeding device that is biased by the biasing means 62 in the direction opposite to the feeding direction. According to the present invention, the stopper 61 is displaced according to the pushing force of the sheet S while maintaining a constant shape, so that the separating action of the sheet S by the wall portion 5 is more effective than the case where the stopper 61 is made of a flexible material. Stabilize.

According to a tenth aspect of the invention, the sheet feeding device 2 according to any one of the first to ninth aspects and the wall portion 5 of the sheet feeding device 2 are arranged in front of the sheet feeding direction, and ink drops are applied to the sheet S. It is characterized by a printing device provided with a jetting print head 13. Therefore, it is possible to reduce printing errors due to paper supply failure.

[0017]

1 to 6 show an embodiment in which the present invention is applied to an ink jet printer.
As is clear from FIG. 1, this inkjet printer has a printing mechanism 1 for performing a predetermined printing on the paper S, and a paper feeding device 2 for feeding the paper S to the printing mechanism 1 one by one. The sheet S is a so-called cut sheet cut into a rectangular shape having a predetermined size.

The printing mechanism 1 is provided with a carriage 11 that reciprocates along a guide rail 10, an ink cartridge 12 supported by the carriage 11, and a print head 13. The guide rail 10 is arranged in the width direction of the sheet S supplied from the sheet feeding device 2, that is, in the direction parallel to the surface of the sheet S and orthogonal to the feeding direction of the sheet S (direction of arrow A in the drawing). At the time of printing, the carriage 11 is reciprocally driven by a drive source (not shown) such as a motor, and ink droplets are ejected from the print head 13 toward the paper S passing thereunder, whereby characters and figures are formed on the paper S. Printed. Although the feeding direction of the sheet S changes depending on the configuration of the moving path of the sheet S, in FIG.
This is represented by the direction in which the paper S is sent out from.
Hereinafter, the feeding direction means the direction of arrow A in FIG. 1 unless otherwise specified.

The paper feeding device 2 is provided with a hopper 3 for accommodating the sheets S in a stacked state, a feeding mechanism 4 for feeding the sheets S from the hopper 3, and a wall provided so that the sheets S fed from the hopper 3 abut. It has a section 5, a stopper mechanism 6 provided on the wall section 5, and a conveyance mechanism 7 that is arranged in front of the wall section 5 in the sheet S feeding direction and conveys the sheet S directly below the print head 13.

The hopper 3 is provided with a paper feed cassette 30 which can be attached to and detached from the printer. Paper cassette 30
Is a cassette receiving surface 8 formed on the printer frame 8.
With reference to 0 and 81, the sheet is supported in an obliquely inclined state with its leading end 300 side (discharge end side of the sheet S) facing down. A push-up plate 31 is provided inside the paper feed cassette 30, and sheets S are stacked on the upper surface 310 of the push-up plate 31. As shown in FIG. 2, on the side of the push-up plate 31, a pair of paper guides 32 for sandwiching the paper S in its width direction (vertical direction in FIG. 2),
33 is provided. The first one arranged on the lower side in FIG.
The paper guide 32 is fixed, and the second paper guide 33 on the opposite side is movable in the width direction of the paper S.

The sheet S placed on the push-up plate 31 is abutted against the first sheet guide 32 and positioned in the width direction,
The second sheet guide 33 is abutted against the positioned sheet S. Therefore, the sheets S stored in the hopper 3 are
Is held so that the side that abuts the first sheet guide 32 is at a substantially constant position regardless of the sheet width. Note that the first paper guide 32 may be adjusted in position in the width direction of the paper S to some extent, or a supplementary paper guide may be attached to the first paper guide 32 depending on the paper width. Even in that case, the sheet S is positioned in the width direction with the first sheet guide 32 as a reference, and the position of the second sheet guide 33 is adjusted according to the sheet width.

As shown in FIG. 1, the push-up plate 31 is rotatable about a rotary shaft 34 provided on the rear end 301 side of the paper feed cassette 30, and is biased toward the delivery mechanism 4 by a spring 35. To be done. Thereby, the leading end side of the paper S is pushed up. Note that the rotation shaft 34 is parallel to the width direction of the sheet S.
The push-up plate 31 is formed of, for example, resin, and the upper surface 310 from which the material is exposed has a relatively small coefficient of friction. Therefore, the frictional resistance between the lowermost sheet S in the hopper 3 and the upper surface 310 of the push-up plate 31 is smaller than the frictional resistance between the stacked sheets S, so that the number of sheets S is smaller. When the number is small (for example, when the number of sheets is two or three), there is a possibility that all the sheets S slide on the upper surface 310 of the push-up plate 31 and are sent out at once. Therefore, a friction member 36 for restraining the lowermost sheet S in the hopper 3 is attached to the upper surface 310 of the push-up plate 31. For example, cork is used as the friction member 36.

As shown in FIGS. 1 and 2, the delivery mechanism 4
Is a support shaft 40 parallel to the width direction of the paper S, and a support shaft 40
A pair of paper feed rollers 41 mounted at intervals above
a, 41b and five collars 42a, 42b, 42c,
It has 42d and 42e. In addition, each paper feed roller 41a,
When it is not necessary to distinguish 41b, these are referred to as a paper feed roller 41, and when it is not necessary to distinguish between the colors 42a to 42e, these are referred to as a color 42.

The support shaft 40 is driven by a drive source (not shown) in FIG.
Can be rotated both clockwise and counterclockwise. As shown in FIG. 3, the sheet feeding roller 41 includes a circumferential portion 410 that is curved so as to draw an arc that is coaxial with the support shaft 40, and a chordal portion that is receded to the center side in the radial direction from the circumferential portion 410. 41
And 1. The paper feed roller 41 is rotatable integrally with the support shaft 40, and a friction member 412 made of rubber or the like is provided on the outer circumference of the circumferential portion 410 and the chordal portion 411 to increase the friction coefficient.
Is covered. The circumferential portion 410 has a length necessary to send out one sheet S in the circumferential direction between the transport roller 70 of the transport mechanism 7 and the driven roller 71 (see FIG. 1).

The collar 42 is formed in a disk shape having an outer peripheral surface 420 having a constant curvature and is rotatable relative to the support shaft 40. The outer diameter φA of the collar 42 is the paper feed roller 4
1 is set to be slightly smaller than the outer diameter φB (outer diameter including the friction member) of the circumferential portion 410, and therefore the outer peripheral surface 420 of the collar 42 is radially outward of the chordal portion 411 of the sheet feeding roller 41. To position. When the support shaft 40 rotates clockwise in FIG. 1 and the circumferential portion 410 of the paper feed roller 41 faces the hopper 3, the paper S pushed up by the push-up plate 31 is pressed against the outer circumference of the paper feed roller 41, As a result, the uppermost sheet S of the hopper 3 is pushed out. When the rotation of the paper feed roller 41 progresses and the chordal portion 411 is fed toward the hopper 3, the paper S left in the hopper 3 is abutted against the outer peripheral surface of the collar 42. As a result, after the delivery of the paper S is completed,
While the paper feed roller 41 is held in a state of being separated from the paper S, the color 42 is rotated following the paper S transported by the transport mechanism 7. Until the feeding of the next sheet S is started, the lifting of the sheet S is prevented. As a result, the double feeding (a state in which two or more sheets are fed in an overlapping manner) due to the lifting of the sheet S is prevented. It is.

The outer diameter φA of the collar 42 is preferably set to 94 to 97% of the outer diameter φB of the paper feed roller 41. 9
If it is less than 4%, the partner contacting the paper S is the paper feed roller 41.
And the collar 42, the push-up plate 31 swings largely up and down, and the shock may cause the paper S to slide toward the leading end side of the hopper 3 and induce double feeding. On the other hand, when it exceeds 97%, the paper feed roller 41 and the paper S
The elastic deformation in the radial direction of the paper feed roller 41 when the paper comes into contact with the collar 42 is prevented by the collar 42, and as a result, the paper feed roller 4
There is a possibility that the frictional force between the sheet 1 and the sheet S is insufficient and a sufficient feeding force cannot be applied to the sheet S. The outer diameters φA of the collars 42a to 42e may be set to different values or may be set to the same value within the appropriate range.

As shown in FIG. 2, as the collar 42, the first collar 42a arranged on the center line L between the pair of sheet feeding rollers 41 and the side near the first sheet guide 32 are provided. A second collar 42b arranged between the first paper feed roller 41a and the first collar 42a, and a third color 42b arranged closer to the first paper guide 32 than the first paper feed roller 41a. Color 42c, the second paper feed roller 41b far from the first paper guide 32, and the first color 42a.
A fourth collar 42d disposed between the first paper guide 32 and a fourth collar 42d disposed between the second paper feed roller 41b and the fourth paper 42d.

The first paper guide 32 and the first collar 42
The distance D1 from a is the same as or slightly smaller than the minimum value Wmin of the paper width that can be used in the printer. Therefore, as shown in FIG. 2, when the standard sheet S1 corresponding to the minimum sheet width Wmin is mounted so that the long side thereof coincides with the feeding direction of the sheet S1 (the state is shown by hatching). The sheet S1 comes into contact with the first sheet feeding roller 41a and the first to third three collars 42a to 42c. In addition, as the minimum paper S1, official postcards (10
0 mm × 148 mm) is assumed, but other types of paper may be used.

The distance D2 between the first paper guide 32 and the second paper feed roller 41b is the minimum paper S1 described above.
The same as or slightly smaller than the long side dimension of. Therefore, when the smallest sheet S1 is mounted so that its short side coincides with the feeding direction (the state is indicated by hatching in the direction opposite to the above), the sheet S1 is the first and second sheet feeding rollers 41a. , 41b, and the first to fourth collars 42a to 42d.

The first paper guide 32 and the fifth collar 42
The distance D3 from e is slightly smaller than the maximum value Wmax of the paper width that can be used in the printer. Therefore, when the sheet S2 having the maximum sheet width Wmax is mounted, the sheet S2 is supplied to both the first and second sheet feeding rollers 41a and 41b, and the first to fifth five colors 42a to 42e. Contact with. The maximum value Wmax of the paper width is A4
Paper (210 mm x 297 mm) or letter paper (21
6 mm x 279 mm) short side dimension is assumed.

The three collars 42a, 42b, 42d sandwiched between the paper feed rollers 41a, 41b are the second collar 42.
b and the fourth color 42d and the respective paper feed rollers 41a, 41
The distance D4 from b is these three collars 42a, 42b,
It is arranged to be sufficiently smaller than the mutual distance D5 of 42d. In this way, pressing the paper S near the paper feed rollers 41a and 41b is effective in preventing the double feeding of the paper S. Moreover, the third collar 42c and the fifth collar 42
e, the color 4 is applied to the paper feed rollers 41a and 41b.
When the sheet S is pressed from the opposite side of 2b and 42d, it is possible to more reliably prevent the double feeding due to the floating of the sheet S. The distance between the third color 42c and the fifth color 42e and the paper feed rollers 41a and 41b is set larger than the distance D4.

A pair of friction members 36 of the push-up plate 31 are provided so as to face the paper feed rollers 41a and 41b and the second and fourth collars 42b and 42d adjacent thereto. As a result, the force of the spring 35 acting on the push-up plate 31 is applied to the feed rollers 41a and 41b and the collar 42.
It is possible to enhance the separation effect of the paper S by the friction member 36 by linearly acting between the b and 42d and the friction member 36. In the illustrated example, the distance D is set with reference to the widthwise center positions of the paper feed roller 41 and the collar 42.
1 to D5 are shown.

As shown in FIG. 1, the wall portion 5 is formed integrally with the printer frame 8. Details of the wall portion 5 are shown in FIGS. 4 and 5. On the wall portion 5, a paper receiving surface 50 that receives the paper S that descends from the leading end of the paper feeding cassette 30, and a paper feeding direction that is continuous above the paper receiving surface 50 and that moves away from the paper feeding cassette 30 upwards. Inclined surface 51 inclined to
Are formed. The paper S delivered from the paper feed cassette 30 gets over the wall portion 5 and moves to the transport mechanism 7 side. As shown in FIG. 2, the inclined surface 51 is provided with a hole 510, and the stopper mechanism 6 described above is provided in the hole 510.
Is arranged. The inclined surface 51 may be curved,
A ridge 511 extending in the feeding direction may be provided on the surface. When the ridge 511 is provided, the upper surface of the ridge 511 defines the shape of the inclined surface 51.

The stopper mechanism 6 rotates around a rotary shaft 60 provided on the bottom side of the hopper 3 in parallel with the width direction of the sheet S, and is retractable from the inclined surface 51, and the stopper 61. And a coil spring (biasing means) 62 for biasing the inclined surface 51 so as to project toward the hopper 3 side. The arm 63 provided integrally with the stopper 61 has a hole 51
When the stopper 61 comes into contact with one side edge of the inclined surface 5,
The position projecting the maximum from 1 is restricted. The rotation shaft 60 and the coil spring 62 are supported by the frame 8. The stopper 61 is provided with a contact surface 610 for the sheet S. When the stopper 61 projects from the inclined surface 51, the paper S
The contact surface 610 has a greater gradient than the inclined surface 51 with respect to the feeding direction.

As shown in FIG. 5A, the stopper 61
Contact surface 610 when the maximum protrusion from the inclined surface 51.
The position P1 at which the inclined surface 51 intersects with the inclined surface 51 is substantially equal to the position at which the leading edge of the paper S fed from the hopper 3 abuts on the wall portion 5. The angle of the push-up plate 31 changes according to the number of sheets S in the hopper 3, and the position at which the leading edge of the sheet S starts contacting the wall portion 5 also changes accordingly. Therefore, at the intersecting position P1, the contact position of the leading edge of the sheet S is the inclined surface 5.
It is desirable to set it as the reference when it is most biased to the 1 side, that is, when the number of sheets S in the hopper 3 is the smallest.

The stopper 61 is made of resin similarly to the printer frame 8, and its rigidity is set high so as to maintain a constant shape against the pushing force of the sheet S which abuts on the contact surface 610. The force by which the coil spring 62 pushes the stopper 61 depends on the rigidity of the sheet S, and the stopper 61
, So that an appropriate separating effect according to the rigidity of the sheet S is ensured.

That is, when the paper S having high rigidity (for example, thick paper such as a postcard or an envelope) pushes the contact surface, the stopper 61 is pushed to almost the same plane as the inclined surface 51 as shown by the solid line in FIG. The tip of S is sent out from the hopper 3 while sliding on the inclined surface 51. At this time, the hopper 3
Even if a plurality of sheets S are simultaneously sent from the sheet S, the sheets S are easily separated from each other by hitting the inclined surface 51 and bending along the inclined surface 51. As a result, only the uppermost sheet S is pushed by the sheet feeding roller 41 and the inclined surface 51
Get over. On the other hand, when the thin and low-rigidity sheet S pushes the stopper 61, the spring 61 is hardly compressed by the rigidity of the sheet S and the stopper 61 projects from the inclined surface 51 as shown in FIG. 5 (b),
As shown in (c), the paper S is sent out so as to get over the stopper 61. In this case, the stopper 61
Since the leading end of the sheet S is largely bent as compared with the case where the sheet S is buried under the inclined surface 51, the sheet S having low rigidity is sufficiently separated, and the sheet S below the uppermost sheet S is stopped by the stopper 61.
Is surely restrained at.

Since the sheet S having low rigidity is exclusively separated by the stopper 61, the slope of the inclined surface 51 may be set so that an appropriate separating action is exerted on the sheet S having high rigidity. As a result, various sheets S can be reliably separated regardless of their rigidity. When the slope of the inclined surface 51 is set to be large in accordance with the sheet S having low rigidity, the sheet S having high rigidity cannot climb over the inclined surface 51, and the sheet S remains in the hopper 3 and is fed by the sheet feeding roller. There is a high possibility that 41 will idle.

The appropriate value of the spring force of the coil spring changes depending on the rigidity range of the paper S used, but in addition to this, the maximum weight of the paper S accommodated in the hopper 3, the hopper 3
Also, the angle between the sheet S accommodated in the sheet and the inclined surface 51, the force of the sheet feeding roller 41 pushing the sheet S, and the force of the push-up plate 31 pushing the sheet S to the sheet feeding roller 41 side are varied. However, converted into a force required to push the stopper 61 completely under the inclined surface 51, the total weight of the paper S in the hopper 3 is not more than 200 g, preferably not more than 16 g.
It is recommended to set it to 0 g or less.

A friction member may be attached to the contact surface of the stopper 61, or the contact surface may be processed to have a high friction coefficient to increase the resistance when the sheet S passes over the stopper 61. However, in order to prevent the paper feed roller 41 from idling on the paper S, it is necessary to consider that the frictional force between the paper S and the stopper 61 is smaller than the frictional force acting between the paper feed roller 41 and the paper S.

As shown in FIG. 2, the stopper 61 is arranged on the center line L of the pair of paper feed rollers 41 in the width direction of the paper S. Therefore, the common stopper 61 can be used for both the sheet S1 that contacts only the sheet feeding roller 41a and the sheet S2 that contacts both the sheet feeding rollers 41a and 41b, and the number of stoppers 61 can be minimized. . Further, in the width direction of the paper S, the pair of paper feed rollers 41
Since the resistance of the stopper 61 is applied to the position where the distance between a and 41b is roughly divided into two, the skew of the sheet S (the state in which the sheet S moves obliquely with respect to the feeding direction) is prevented. As shown by an imaginary line in FIG. 1, the stopper mechanism 6 may be added between the first paper feed roller 41a and the first paper guide 32. In addition, various arrangements of the paper feed roller 41 and the stopper 61 in the paper width direction can be changed, which will be described later.

A concave portion 512 is provided on the inclined surface 51 so as to be located on an extension of the pair of paper feed rollers 41 in the feeding direction of the paper S. As shown by an imaginary line S ′ in FIG. 2, the leading end of the sheet S pressed by the sheet feeding roller 41 is deformed so as to fall into these recesses 512, and at the same time, the stopper 61 is provided at a substantially central position between the recesses 512. Is pushed back in the opposite direction. As a result, the effect of separating the paper S is enhanced. Although the width of the recess 512 is set to be slightly larger than the width of the paper feed roller 41, it may be set to be equal to or smaller than the width of the paper feed roller 41. The recess 512
May be formed in the same shape as the hole 510, and the stopper mechanism 6 may be installed in the recess 512.

As shown in FIGS. 2 and 6, a pair of groove portions 52 are formed in the wall portion 5 so as to be aligned with the stopper 61 and the width direction of the paper S. Friction members 53 are respectively bonded to these groove portions 52, and these friction members 53 are pulled out from the groove portions 52 in the feeding direction and exposed on the inclined surface 51. These friction members 53 increase the friction coefficient of the inclined surface 51 to be higher than that of the contact surface of the stopper 61 and increase the inclination of the inclined surface 5.
The separation performance of the paper S by 1 is improved. The inclined surface 5
When the ridge 511 is provided on the first ridge, the exposed portion of the friction member 53 on the inclined surface 51 is set to have substantially the same height as the upper surface of the ridge 511.

A position P2 where the friction member 53 is exposed on the inclined surface 51 is a position P1 (see FIG. 5) where the contact surface 610 of the stopper 61 that protrudes the maximum to the inclined surface 51 and the inclined surface 51 intersect.
It is more biased in the feeding direction than (see (a)). The reason is that the static friction force between the front end of the sheet S that is abutted against the wall portion 5 and is stationary and the wall portion 5 is reduced to prevent the paper feed roller 41 from idling when the sheet S starts moving. In addition, after the sheet S starts moving, the frictional resistance between the inclined surface 51 and the sheet S is increased to enhance the separating effect of the sheet S. When the position P1 changes depending on the rigidity of the paper S, it is desirable to determine the position P1 with reference to the case of using the paper S having the highest rigidity.

The mounting position of the friction member 53 in the width direction of the paper S is the center line L between the feeding rollers 41a and 41b.
Are set symmetrically with respect to each other, whereby the feed force acting on the paper S from the paper feed roller 41 and the resistance of the friction member 53 are balanced to prevent the paper S from skewing. This point is the same as the relationship between the paper feed roller 41 and the stopper 61.

The friction member 53 is formed by adhering alumina particles to the surface of a polyester film, and is composed of other known high friction members. It should be noted that the friction member 53 may be attached to the inclined surface 51 only in an area distant from the position P2 in FIG. 6 in the feeding direction without providing the groove portion 52. However,
When a part of the friction member 53 is housed in the groove 52, there is no possibility that the end of the friction member 53 is pushed by the front end of the paper S and peeled off, and the joint area between the friction member 53 and the wall 5 increases. The joint strength is improved. Instead of the friction member 53, a part of the inclined surface 51 may be processed to increase the friction coefficient.

The sheet S that has passed over the wall portion 5 is guided between the transport roller 70 and the driven roller 71 of the transport mechanism 7. The conveying roller 70 is rotationally driven in the clockwise direction in FIG. 1 until the paper S is fed out by the paper feeding roller 41 by a predetermined length, and then is rotationally driven in the counterclockwise direction in FIG. As a result, the leading edge of the sheet S is fed to the printing mechanism 1 side while being aligned in the axial direction of the transport roller 70.

The present invention is not limited to the above-described embodiment, but can be implemented in various forms. 7 to 14 show different embodiments. In FIG. 7, the stopper mechanism 6 is attached to the paper feed roller 41.
This is an example in which one is provided on each of the extensions a and 41b in the feed direction. In this case, the paper feed roller 41
Since the feed forces of a and 41b are linearly received by the stopper 61 located on the line of action thereof, the skew feeding of the sheet S can be more reliably prevented.

FIG. 8 shows that the stopper mechanism 6 is closer to the first paper feed roller 41a side than the example of FIG. 2 and is farther from the first paper guide 32 than the second paper feed roller 41b. In this example, a stopper mechanism 6 is added. In this case, the two stoppers 61 contact the large-width sheet S2, and only the single stopper 61 contacts the small-width sheet S1. Since the paper S2 having a large width has a large weight, if the number of contacts of the stoppers 61 is increased as shown in FIG. 8, the same separation effect can be obtained regardless of the paper width.

When a plurality of stopper mechanisms 6 are provided as shown in FIGS. 7 and 8, it is necessary to limit variations in the force with which each stopper 61 presses the sheet S. The allowable range of variation is within ± 50% of the load required to press the stopper 61 under the inclined surface 51, preferably ±
It should be set within 10%.

FIG. 9 shows a pair of paper guides 37, which are movable in the width direction of the paper S, instead of the paper guides 32 and 33 shown in FIG.
This is an example in which is provided. The paper guides 37 are connected to each other via an interlocking mechanism 38. The interlocking mechanism 38 includes a common pinion gear 380 and a pair of racks 381 that mesh with the pinion gear 380.
The paper guide 37 is connected to each rack 381. With this interlocking mechanism 38, the paper guide 37
Moves symmetrically in the width direction of the paper S with respect to the center line CL in the width direction of the hopper 3 '. Therefore, the center in the width direction of the sheets S stored in the hopper 3 ′ coincides with the center line CL in the width direction of the hopper 3 ′ regardless of the sheet width. The pair of paper feed rollers 41a and 41b are arranged symmetrically with respect to the center line CL of the hopper 3 ', and the stopper mechanism 6 is provided on the center line CL.
Therefore, regardless of the width of the sheet S, the sheet S hits the stopper 61 at the center position in the width direction. Therefore, all the sheets S can be handled by providing the single stopper 61. Further, the force of the paper feed rollers 41a and 41b sending out the paper S and the force of the stopper 6 pushing back the paper S act symmetrically with respect to the center line of the paper S in the width direction, and the skew of the paper S is surely prevented. . When the hopper 3'of FIG. 9 is used, a single paper feed roller 41 may be provided on the center line CL as shown in FIG. 10, instead of the pair of paper feed rollers 41a and 41b.

Also in the examples of FIGS. 7, 8 and 10, the friction members 36 and 53 shown in FIG. 2 may be provided. In the example of FIG. 8, the recess 512 may be provided. Instead of the paper feed rollers 41a and 41b having the same width, paper feed rollers 41c and 41d having different widths may be used as shown in FIG.
In this case, the feeding force F1 of each paper feed roller 41c, 41d,
Since the sizes of F2 are different from each other, their feeding force F
It is preferable to provide one or more stopper mechanisms 6 symmetrically in the width direction of the sheet S with respect to the line of action AL of the resultant force F3 of 1, F2. The friction member 53 may also be arranged symmetrically with respect to the action line AL (that is, δ1 = δ2 in FIG. 11). The same applies when three or more paper feed rollers 41 are used.

12 to 14 show another embodiment relating to the stopper mechanism 6. FIG. 12 shows the contact surface 6 for the paper S.
13A is a stopper 61A in which 10A is formed in a concave curved surface.
Indicate stoppers 61B each having a contact surface 610B substantially perpendicular to the sheet S. In the stopper 61B of FIG. 13, a groove portion 611 extending in the width direction of the sheet S is provided on the contact surface 610B. The front end of the paper S is provided with a groove 61.
1 can be engaged to enhance the separation effect. However, the groove portion 611 may be omitted. FIG. 14 shows an example in which a stopper 61C having a contact surface 610C substantially perpendicular to the paper S is supported by a pair of springs 63 so as to be movable in a direction substantially parallel to the feeding direction of the paper S from the hopper 3. In this example, the contact surface 610B is irrespective of the position of the stopper 61C.
It is possible to push back the paper S in a certain direction while keeping the gradient of No.

In addition to the above, the present invention can be implemented in various forms. For example, the stopper 6 is provided on the entire inclined surface 51.
1 may be provided. The stopper 61 may be made of an elastic material such as rubber and may be deformed to some extent by the pushing force of the paper S. Even in such a case, as long as the two types of the inclined surface 51 and the contact surface 610 of the stopper 61 are selectively brought into contact with the paper S, the types of paper that can be separated can be expanded as compared with the related art. The paper feeding device of the present invention is not limited to an ink jet printer, but can be applied to various printers such as a laser printer, a copier, and a facsimile. The present invention can be applied to a sheet feeding device that holds sheets horizontally.

[0055]

As described above, according to the first aspect of the invention, the inclined surface and the stopper which can be retracted from and into the inclined surface can be selectively used as a means for giving a separating action to the sheet, and the stopper can be used. The separating action can be variously adjusted depending on the nature of the contact surface with respect to the sheet and the force with which the biasing means biases the stopper. Therefore, it is possible to realize a highly reliable sheet feeding device that can reliably separate various sheets. Claim 2
According to the invention of claim 8, in addition to the effect by the invention of claim 1, the following operational effect can be obtained. According to the second aspect of the invention, the separating action can be stabilized more than when the stopper is made of a flexible material. Moreover, since the room for selecting the stopper material can be expanded, the stopper can be configured with an emphasis on cost and durability, thereby reducing the manufacturing cost and maintenance cost of the sheet feeding device. According to the third aspect of the present invention, since the paper with low rigidity can be separated only by the stopper, the inclined surface can be configured so as to focus on the separation of the paper with high rigidity, thereby suppressing the resistance of the inclined surface with respect to the paper with high rigidity. It is possible to prevent the paper feed roller from idling. According to the invention of claim 4, the stopper having a large gradient can flexibly deform and separate the sheet having a small rigidity, while the inclination of the inclined surface can be small, so that the resistance of the inclined surface to the sheet having a large rigidity can be suppressed. It is possible to prevent the paper feed roller from idling. In the invention of claim 5, the contact surface of the stopper can push the paper back to the hopper side to surely separate the paper from each other. According to the sixth aspect of the present invention, the leading end of the sheet moving on the stopper is temporarily restrained by the groove portion, thereby causing a large bending of the sheet and promoting separation of the sheets. According to the invention of claim 7, the slope of the contact surface of the stopper is increased as the force with which the paper pushes the stopper decreases.
As a result, the smaller the rigidity of the sheet, the stronger the separating action of the sheet by the stopper. According to the invention of claim 8, the paper can be pushed back in a fixed direction regardless of the position of the stopper.

According to the ninth aspect of the invention, the separating action can be stabilized more than when the stopper is made of a flexible material. Moreover, since the room for selecting the stopper material can be expanded, the stopper can be configured with an emphasis on cost and durability, thereby reducing the manufacturing cost and maintenance cost of the sheet feeding device.

According to the invention of claim 10, claims 1 to 9
By utilizing the excellent paper feeding performance of the paper feeding device, it is possible to provide a highly reliable inkjet printer in which there are few printing mistakes caused by defective paper feeding.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a portion from a hopper to a printing mechanism of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a plan view from the direction of arrow II in FIG.

FIG. 3 is an enlarged view showing a paper feed roller and a color of the paper feed device of FIG.

FIG. 4 is a diagram showing a state in which a stopper is pushed in by a sheet having high rigidity.

FIG. 5 is a diagram illustrating a state in which a sheet having low rigidity is fed over a stopper.

6 is a sectional view taken along line VI-VI of FIG.

7 is a diagram showing an embodiment in which the number of stoppers is changed to two with respect to FIG.

8 is a diagram showing an embodiment in which the position of the stopper is changed with respect to FIG.

FIG. 9 is a plan view showing an embodiment in which the center line of the paper and the center line of the hopper are always aligned with each other, corresponding to FIG.

10 is a diagram showing an embodiment in which the number of paper feed rollers is reduced to one as compared with FIG.

FIG. 11 is a diagram showing an arrangement of stoppers and friction members on an inclined surface when using paper feed rollers having different widths.

FIG. 12 is a diagram showing an embodiment in which a contact surface of a stopper with respect to a sheet is changed.

FIG. 13 is a diagram showing another embodiment in which the contact surface of the stopper with respect to the paper is changed.

FIG. 14 is a diagram showing an embodiment in which a stopper moving direction is substantially parallel to a sheet feeding direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Printing mechanism 2 ... Paper feeding device 3 ... Hopper 4 ... Delivery mechanism 5 ... Wall part 6 ... Stopper mechanism 7 ... Conveying mechanism 8 ... Printer frame 13 ... Print head 30 ... Paper feeding cassette 31 ... Push-up plate 41 ... Paper feeding roller 42 ... Collar 51 ... Wall inclined surface 61 ... Stopper 62 ... Coil spring (biasing means) 610 ... Stopper contact surface 611 ... Stopper groove

Claims (10)

[Claims] 1. A hopper for accommodating sheets in a stacked state, and a sheet feeding roller for contacting a surface of the sheets accommodated in the hopper and delivering the sheets in a predetermined feeding direction, the hopper comprising: A wall portion is provided at an end portion in the feeding direction so that a sheet fed from the hopper abuts against the wall portion, and the wall portion has an inclined surface that gradually inclines in the feeding direction as the sheet moves away from the hopper. A sheet feeding device, wherein a stopper capable of projecting and retracting with respect to the inclined surface is provided, and the stopper is biased by a biasing means in a direction projecting from the inclined surface. 2. The paper feeding apparatus according to claim 1, wherein the stopper has a rigidity that keeps a fixed shape against a pressing force of the abutted sheet. 3. The urging means is provided so that the stopper projects from the inclined surface when the rigidity of the paper is low, and the stopper is recessed below the inclined surface when the rigidity of the paper is high. The sheet feeding device according to claim 1, wherein 4. The contact surface of the stopper with respect to the sheet is provided so as to have a greater gradient than the inclined surface with respect to the feeding direction.
Paper feeder as described. 5. The contact surface is provided so as to be substantially perpendicular to the feed direction, or to be inclined to a side opposite to the feed direction with respect to a right angle position.
Paper feeder as described. 6. The sheet feeding device according to claim 1, wherein a groove portion extending in a width direction of the sheet is provided on a contact surface of the stopper with respect to the sheet. 7. The stopper according to claim 1, wherein the stopper is retracted from the inclined surface by a rotational movement around a rotation axis set parallel to the width direction of the sheet on the bottom side of the hopper. Paper feeder. 8. The sheet feeding device according to claim 1, wherein the stopper is moved in and out of the inclined surface by a linear movement substantially parallel to the feeding direction. 9. A hopper for accommodating sheets of paper in a stacked state, and a paper feed roller for coming into contact with a surface of the sheets of paper accommodated in the hopper and delivering the paper in a predetermined feeding direction. A wall portion is provided at an end portion in the feeding direction so that a sheet fed from the hopper abuts against the edge portion, and at least a part of the wall portion has a fixed shape against the pushing force of the abutted sheet. A sheet feeding device, characterized in that a stopper having rigidity for holding and displaceable in the feeding direction is provided, and the stopper is urged to the side opposite to the feeding direction by urging means. 10. A paper feeding device according to claim 1, and a print head which is arranged in front of the wall portion of the paper feeding device in the feeding direction and ejects ink droplets onto the paper. A printing apparatus comprising: