JP3478660B2 - Paper feeder and printing apparatus using the same - Google Patents

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 that feeds sheets stacked on a push-up plate one by one by a sheet feeding roller, and a printing apparatus using the same.

[0002]

2. Description of the Related Art As a sheet feeding device used in a printer or the like, a sheet stacked on a push-up plate is fed in a predetermined feeding direction by a sheet feeding roller abutting its surface, and the fed sheet is forward in the feeding direction. It is known that the sheet is abutted against an inclined surface provided on the sheet to be curved, thereby promoting separation of the sheets from each other (see, for example, JP-A-2-132018 and US Pat. No. 5026042).

[0003]

In the above-mentioned apparatus, of the sheets stacked on the push-up plate, only the uppermost sheet passes over the inclined surface and is guided to the predetermined sheet feeding position (for example, the printing position). The other papers are left in front of the inclined surface. However, when the uppermost sheet is fed, the sheet below it may be somewhat dragged toward the inclined surface. Therefore, as the paper is repeatedly fed, the leading edge of the paper left on the push-up plate gradually advances, and if that position exceeds a certain limit, double feeding (a state in which two or more sheets are stacked and sent out) occurs. It often happened. This tendency was remarkable when thin paper having low rigidity was used.

Therefore, it is an object of the present invention to provide a sheet feeding device and a printing device capable of preventing the sheet left on the push-up plate from shifting to the inclined surface side and preventing the double feeding of the sheet. .

[0005]

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

According to the first aspect of the present invention, the push-up plate 31 on which the sheets S are stacked and the sheet S on the push-up plate 31 are contacted to feed the sheet S in a predetermined feeding direction (direction of arrow A in FIG. 1). The sheet feed roller 40 is provided, and an inclined surface 50 that rises as it moves away from the push-up plate 31 in the feed direction is formed in front of the push-up plate 31 in the feed direction. push-up plate 31 so that the angle θ of the large hearing side is reduced with a decrease in load of the sheet S of the angle sandwiched
Is characterized by a paper feeding device that changes its posture. According to the present invention, when the stacking amount of the paper S on the push-up plate 31 decreases,
As a result, the angle θ between the sheet S and the inclined surface 50 becomes smaller. This decrease in the angle θ is equivalent to an increase in the slope of the inclined surface 50 for the paper S delivered from the push-up plate 31. Therefore, when the sheet S gets over the inclined surface 50, the sheet S is more flexed, and double feeding is prevented.

[0007] In the second aspect of the present invention, the sheet feeding apparatus according to claim 1, push-up plate 31 includes a first biasing means 33 for biasing the pressing upper plate 31 in the stacking direction of the paper S, On the upstream side of the first biasing means 33 in the sheet S feeding direction, the second biasing means 34 for biasing the push-up plate 31 in the stacking direction of the sheets S tilts the stacked sheets S. Face 50
The posture is changed such that the larger angle θ of the angles sandwiched by and becomes smaller as the stacking amount of the paper S decreases. According to the present invention, the stacking amount of the paper S on the push-up plate 31
Is reduced, the first biasing means 33 and the second biasing means 3
4, the posture of the push-up plate 31 changes so that the angle θ sandwiched between the paper S and the inclined surface 50 becomes smaller. This decrease in the angle θ is equivalent to an increase in the slope of the inclined surface 50 for the paper S delivered from the push-up plate 31. Therefore, when the sheet S gets over the inclined surface 50, the sheet S is more flexed, and double feeding is prevented.

[0008] In the present invention of claim 3, wherein the sheet feeding apparatus of claim 2, comprising a frame 32 which feed direction Ru is swingably supported on the opposite end of the push-up plate 31, biasing the first force of the hand
The step 33 is provided between the push-up plate 31 and the frame 32, and the second biasing means 34 contacts the first biasing means 33.
Frame 32 from the surface opposite to the surface of the frame 32 you
The push-up plate 31 is biased by directly biasing. According to the invention, the frame 32 is
When is pushed up, the end portion of the push-up plate 31 on the side opposite to the feeding direction is also pushed up accordingly.

According to a fourth aspect of the invention, in the sheet feeding device of the third aspect, the frame 32 is swingable with the end 320 in the feeding direction as a fulcrum. According to the present invention, the inclination of the frame 32 with respect to the inclined surface 50 is changed in the opposite direction to the inclination of the push-up plate 31 with respect to the inclined surface 50, whereby the angle θ sandwiched between the paper S and the inclined surface 50 is changed. S
The posture of the push-up plate 31 can be changed so that the push-up plate 31 becomes smaller in accordance with the decrease in the load amount.

According to the fifth aspect of the present invention, there is an upper surface 310 on which the sheets S are stacked, and the push-up is swingable with the end portion on the opposite side of the sheet S feeding direction as a fulcrum (corresponding to the center of the support shaft 312). A plate 31 and a paper feed roller 40 that is arranged so as to face the upper surface 310 of the push-up plate 31 and sends out the sheets S stacked on the upper surface 310 in the feed direction are provided in front of the push-up plate 31 in the feed direction. The inclined surface 50 that rises as it moves away from the push-up plate 31 in the feeding direction is formed, and the position of the fulcrum of the push-up plate 31 is movable in the stacking direction of the paper S in conjunction with the change in the stacking amount of the paper S. The push-up plate 31 has a sheet S
The paper feeding device is characterized in that the movement amount of the fulcrum due to the decrease of the load amount is set to be larger than the movement amount at the end portion in the feeding direction due to the decrease of the load amount.

[0011]

According to a sixth aspect of the present invention, there is an upper surface 310 on which the sheets S are stacked, and a push-up plate 31 which is swingable about an end portion of the sheet S on the side opposite to the feeding direction, and a lower surface of the push-up plate 31. Three
The frame 32, which is arranged on the 11th side and is swingable about the end 320 in the feeding direction as a fulcrum, is arranged so as to face the upper surface 310 of the push-up plate 31, and feeds the sheets S stacked on the upper surface 310 in the feeding direction. A paper roller 40 is provided, and an inclined surface 50 that rises as it moves away from the push-up plate 31 in the feed direction is formed in front of the push-up plate 31 in the feed direction. A first urging member 33 that is movable to the first urging member 33 and that pushes up the push-up plate 31 toward the sheet feeding roller 40 is interposed between the push-up plate 31 and the frame 32. The paper feeding device is characterized in that a second urging member 34 that urges the frame 32 toward the push-up plate 31 side is provided at a position away from the side opposite to the feeding direction. According to the present invention, the tip end side (the end portion in the feeding direction) of the push-up plate 31 urged by the first urging member 33 rises to the paper feed roller 4 side as the stacking amount of the paper S decreases. To do.
Further, although the push-up plate 31 and the frame 32 are pushed downward due to the weight of the stacked sheets S, the frame 32 is pushed by the second biasing member 34 as the stacking amount decreases.
Is gradually pushed up. Then, the fulcrum of the push-up plate 31 is also pushed up by the pushed-up frame 32.
Therefore, the inclination of the push-up plate 31 with respect to the inclined surface 50 can be properly maintained.

A seventh aspect of the present invention is the sheet feeding device 2 according to any one of the first to sixth aspects, and a print head which is disposed in front of the sheet feeding device 2 in the feeding direction and ejects ink droplets onto the sheet S. And a printing device provided with 13. Therefore, the paper S
It is possible to reduce printing mistakes caused by double feeding of paper.

[0014]

1 to 3 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 single-cut sheet that is cut into a rectangular shape having a certain size.

The printing mechanism 1 includes an ink cartridge 12 on a carriage 11 that reciprocates along a guide rail 10.
And the print head 13 is attached. During printing, the carriage 11 is a drive source (not shown) (for example, a motor).
While being reciprocally driven, ink droplets are ejected from the print head 13 toward the paper S passing thereunder, whereby characters and figures are printed on the paper S.

The sheet feeding device 2 is provided with a top sheet S of the hopper 3.
Is fed in a predetermined feeding direction (the direction of arrow A in FIG. 1) by the paper feed roller mechanism 4 which is brought into contact with the surface thereof, and the leading end of the fed paper S is brought into contact with the inclined surface 50 provided so as to be continuous with the hopper 3, By utilizing the bending of the sheet S at that time, the uppermost sheet S is separated from the sheet S below it and supplied to the printing mechanism 1. The details of the hopper 3 will be described later.

The paper feed roller mechanism 4 has a paper feed roller 40 formed in a substantially semicircular shape, and a disc-shaped collar 41 which is rotatable coaxially with the paper feed roller 40. The paper feed roller 40 is rotationally driven in the clockwise direction in FIG. 1 by a drive source (not shown), and thereby the paper S that contacts the paper feed roller 40 is sent to the inclined surface 50 side. The outer diameter of the collar 41 is somewhat smaller than the feed roller 40.

The inclined surface 50 is formed integrally with the printer frame 5 so as to rise as it moves away from the hopper 3 in the sheet S feeding direction. A stopper mechanism 6 is provided in the middle of the inclined surface 50. The stopper mechanism 6 has a stopper 61 rotatable about a shaft 60, and a coil spring 62 for urging the stopper 61 in a direction projecting from the inclined surface 50. When the rigidity of the paper S delivered from the hopper 3 is small (in the case of thin paper), the stopper 61 largely projects from the inclined surface 50, whereby the leading end of the paper S is greatly curved so as to get over the stopper 61, and the paper S The mutual separation is promoted. On the other hand, when the rigidity of the paper S is large (in the case of thick paper such as postcards and envelopes), the stopper 61 causes the inclined surface 5 to move.
0 is pushed downward, so that the paper S is slanted on the inclined surface 51
The resistance at the time of getting over the sheet is reduced, and the idling of the sheet feeding roller 4 is prevented. The paper S that has passed over the inclined surface 50 is conveyed by the transport mechanism 7.
It is guided between the conveyance roller 70 and the driven roller 71 and is sent to the position just below the print head 13 as the conveyance roller 70 rotates.

As shown in FIGS. 2 and 3, the hopper 3
Is provided with a hopper case 30 that is attachable to and detachable from the printer. The front end 30 of the hopper case 30 is formed by the case receiving surfaces 51 and 52 formed on the printer frame 5.
The sheet is supported in an inclined state with the 0 side (the discharge end side of the sheet S) facing down. A push-up plate 31 is provided inside the hopper case 30.
Is provided, and the paper S is stacked on the upper surface 310 thereof. A frame 32 is provided on the lower surface 311 side of the push-up plate 31. The tip portion 320 of the frame 32 is butted against the step portion 301 of the hopper case 30. A support shaft 312 is provided on the rear end side of the push-up plate 31, and the support shaft 312 penetrates the rear end portion 321 of the frame 32 and the long hole 3 of the hopper case 30.
02 (see FIG. 3). As a result, the push-up plate 3
1 is a frame 32 around the support shaft 312 on the rear end side.
It is swingably supported by.

The long hole 302 is formed by the frame 32 and the step portion 301.
It is formed so as to draw an arc centered around the contact position with. The entire length of the long hole 302 is set so that the support shaft 312 can move in the stacking direction of the paper S (the normal line direction of the upper surface 310) larger than the maximum stacking capacity of the paper S. The maximum stacking amount of the paper S is limited to a value equal to or smaller than the distance between the upper surface 310 and the paper feed roller 40 when the push-up plate 31 is most lowered to the bottom side of the hopper case 30. The first coil spring 3 is provided between the push-up plate 31 and the frame 32.
3 is provided. A first biasing means, that is, a first coil spring 33 is provided between the frame 32 and the hopper case 30.
The second biasing means, that is, the second coil spring 34 is provided closer to the support shaft 312 side.

According to the hopper 3 having the above structure, the first coil spring 33 pushes up the push-up plate 31 toward the paper feed roller mechanism 4, and the sheets S stacked on the push-up plate 31 are thereby fed. Alternatively, it is abutted on the collar 41 as an alternative. Further, since the frame 32 is pushed up by the second coil spring 34, the support shaft 31
2 is also pushed up toward the upper end of the long hole 302. However, as shown in FIG. 1, when the amount of sheets S stacked is large, the weight of the sheets S pushes the push-up plate 31 and the frame 32 to the bottom side of the hopper case 30, respectively, and the second coil spring 34 is pushed. Be shortened.

The first coil spring 33 expands as the stacking amount of the paper S decreases, and the push-up plate 31 swings around the support shaft 312 to increase the angle θ with the inclined surface 50. The second coil spring 34 also gradually expands. Along with that, the frame 32 swings upward with the tip 320 thereof as a fulcrum (see FIG. 2). As a result, the support shaft 312 moves to the upper end side of the elongated hole 302, so that the paper S and the inclined surface 5 are moved.
The angle θ between 0 and 0 becomes smaller as the stacking amount of sheets S decreases. A decrease in the angle θ is equivalent to an increase in the slope of the inclined surface 50 for the paper S. Therefore,
As the stacking amount of the sheets S decreases, the sheets S riding on the inclined surface 50 are largely curved, which prevents double feeding of the sheets S.

The present invention is not limited to the above embodiments and can be implemented in various modes. For example, the frame 32 is not connected to the support shaft 312, but is abutted against the lower surface 311 of the push-up plate 31 on the rear end side of the frame 32 to support the support shaft 312.
You may make it push up the side. The tip 320 of the frame 32 may be rotatably connected to the hopper case 30. The present invention can be applied to a sheet feeding device in which the stopper 61 does not exist on the inclined surface 50. Adjusting the spring force of the second coil spring 34, its load position, the length of the long hole 302, etc.,
It is also possible to keep the angle θ substantially constant regardless of the amount of sheets S stacked.

The paper feeding device of the present invention is not limited to the ink jet printer, but can be applied to other printers such as a laser printer, various printing devices such as a copying machine and a facsimile. The present invention can be applied even to a paper feeding device that holds paper substantially horizontally.

[0025]

As described above, according to the inventions of claims 1 to 4, as the stacking amount of sheets decreases, the inclination of the inclined surface relative to the sheets relatively increases and the separating action acting on the sheets is achieved. Since it becomes large, it is possible to realize a paper feeding device excellent in separation performance in which double feeding does not occur even when a large number of papers are continuously fed.
According to the second aspect of the present invention, it is possible to give the paper on the push-up plate an appropriate inclination according to the stacking amount while pushing up the paper feed roller toward the push-up plate. According to the third aspect of the present invention, it is possible to provide the sheet on the push-up plate with an appropriate inclination according to the stacking amount by using the frame. According to the fourth aspect of the present invention, by changing the posture of the frame in the opposite direction with respect to the change of the posture of the push-up plate, it is possible to give the paper on the push-up plate an appropriate inclination according to the stacking amount.

According to the fifth aspect of the present invention, the fulcrum position of the push-up plate is moved in association with the change in the stacking amount of the paper, so that the inclination of the inclined surface with respect to the paper falls within an appropriate range according to the stacking amount of the paper. It is possible to prevent double feeding of paper regardless of the loading amount. Further, the slope of the inclined surface with respect to the paper is relatively increased as the stacking amount of the paper is decreased, thereby improving the separation performance when a large number of papers are continuously fed.

According to the sixth aspect of the present invention, the fulcrum position of the push-up plate moves in the stacking direction in association with the change in the stacking amount of the paper, and the inclination of the inclined surface with respect to the paper is appropriate according to the stacking amount of the paper. Kept in range. Therefore, it is possible to prevent the double feeding of the sheets regardless of the amount of the sheets stacked.

According to the seventh aspect of the invention, by utilizing the excellent sheet feeding performance of the sheet feeding device of the first to sixth aspects, there are few printing mistakes caused by defective sheet feeding and the inkjet printer is highly reliable. Can be provided.

[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 diagram showing a state in which the amount of sheets stacked is smaller than that in the state of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

[Explanation of symbols]

1 ... Printing mechanism 2 ... Paper feeder 13 ... Print head 30 ... Hopper case 31 ... Push-up plate 32 ... Frame 33 ... First coil spring 34 ... Second coil spring 41 ... Paper feed roller 50 ... Inclined surface θ: Angle between paper and inclined surface

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 1/00-3/68

Claims (7)

(57) [Claims] 1. A push-up plate on which sheets are stacked, and a paper feed roller that comes into contact with the paper on the push-up plate and feeds the paper in a predetermined feed direction, the feed direction with respect to the push-up plate. In front of, an inclined surface that rises as it moves away from the push-up plate in the feeding direction is formed, and the push-up plate has a larger angle among the angles sandwiched between the stacked sheets and the inclined surface. A paper feeding device characterized in that its posture is changed so as to become smaller as the stacking amount of paper decreases. 2. The push-up plate is configured to connect the push-up plate to the paper.
First urging means for urging in the loading direction , and the first
At the upstream side of the sheet feeding direction of the urging means of
By the second biasing means for urging the push-up plate stacking direction of the paper, of the angle sandwiched between the stacked paper sheet and the inclined surface, the loading amount of the larger angle the sheet 2. The paper feeding device according to claim 1, wherein the posture is changed so as to become smaller as the number of sheets decreases. Wherein comprising the frame feed direction Ru is swingably supported on the opposite end of the push-up plate, said first biasing means, and the said push-up plate frame
The second biasing means is provided between the first biasing means and the second biasing means.
The sheet feeding device according to claim 2, wherein the push-up plate is biased by directly biasing the frame from a surface opposite to the surface of the frame. 4. The sheet feeding device according to claim 3, wherein the frame is swingable about an end portion in the feeding direction as a fulcrum. 5. A push-up plate having an upper surface on which sheets are stacked and swingable about an end opposite to the sheet feeding direction as a fulcrum, and arranged to face the upper surface of the push-up plate, A sheet feeding roller that feeds the sheets stacked on the upper surface in the feeding direction, and an inclined surface that rises as it moves away from the pushing plate in the feeding direction is formed in front of the pushing plate in the feeding direction. And the position of the fulcrum of the push-up plate is movable in the stacking direction of the paper in association with the change in the stacking amount of the paper.
The push-up plate moves the fulcrum due to the reduction of the paper load.
A sheet feeding device, wherein the amount of movement is set to be larger than the amount of movement at the end portion in the feeding direction due to the reduction of the stacking amount . 6. A push-up plate having an upper surface on which sheets are stacked and swingable about an end opposite to the sheet feeding direction as a fulcrum. A push-up plate, and a feed roller that is arranged so as to face the upper surface of the push-up plate and feeds the sheets stacked on the upper surface in the feeding direction. In front of the plate in the feeding direction, an inclined surface is formed which rises as it moves away from the lifting plate in the feeding direction, and the position of the fulcrum of the lifting plate is movable in the stacking direction of the sheets. A first biasing member that pushes up the plate toward the paper feed roller is interposed between the push-up plate and the frame, and separated from the first biasing member on the opposite side in the feeding direction. Position the frame on the push-up plate side A sheet feeding device comprising a second urging member for urging the sheet feeding device. A sheet feeding apparatus according to any one of claims 7 claims 1-6, provided with a print head for ejecting ink droplets onto the sheet is arranged in the feeding direction forward of said feed device A printing device characterized by the above.