TRACTOR AND PRINTER EQUIPPED WITH THE SAME

Abstract

According to one embodiment, a tractor comprises a pin belt, a pair of rotating units and a roller. The pin belt configured as an endless belt, which has a plurality of pins on the outer peripheral surface thereof, wherein the pins are respectively inserted into feeding holes formed on a tractor paper, and the pin belt rotates to convey the tractor paper. The pair of rotating units configured to rotate the pin belt. The roller, which is arranged between the pair of rotating units, with a groove on the outer peripheral surface thereof, wherein the front end of the pin is fitted into the groove, so that the front end of the pin is abutted against the groove to space between the outer peripheral surface of the pin belt and the outer peripheral surface of the roller.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based upon and claims the benefit of priorities from the prior Japanese Patent Applications No. 2011-116026 filed on May 24, 2011 and No. 2012-037865 filed on Feb. 23, 2012, the entire contents of which are hereby incorporated by reference.

FIELD

Embodiments described herein relate to a tractor and a printer which is equipped with the tractor.

BACKGROUND

Conventionally, a printer equipped with a tractor, which conveys a tractor paper, using a pair of left and right rotating pin belts is well known. Feeding holes are respectively formed at the opposite sides of the width direction of the tractor paper along a paper feeding direction (conveying direction). Moreover, a plurality of pins is formed on the outer peripheral surfaces of the pin belt pair along the length direction of the pin belt at regular intervals.

Furthermore, the pins on the outer peripheral surfaces of the pin belt pair are respectively inserted into the feeding holes of the tractor paper and the pin belts are rotated so as to convey the tractor paper in the conveying direction.

However, there is a printer which uses, for the sake of saving space, a tractor that conveys a tractor paper by curving the tractor paper along a guide surface curved into a concave arc shape. This tractor is provided with a roller that presses pin belt to curve the rotation track of the pin belt. Moreover, a groove for accommodating pins is configured in the roller, the outer edge of which is abutted against the outer peripheral surface of the pin belt at the position where the pin belt is abutted against the roller to curve the pin belt (a bend) and the pin belt is driven in the conveying direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a business machine provided with the tractor of an embodiment;

FIG. 2 is a perspective view of the tractor;

FIG. 3 is a side-sectional view of a belt unit;

FIG. 4-1 is a sectional view of the conventional roller and pin belt on a straight line 30, this Figure showing the roller and the pin belt between which no tractor paper is inserted;

FIG. 4-2 is a sectional view of the conventional roller and pin belt on the straight line 30, this Figure showing the roller and the pin belt between which a tractor paper is inserted;

FIG. 5 is a sectional view of the roller and the pin belt on the straight line 30 according to the embodiment;

FIG. 6 is a diagram showing an example of the pin belt of which the height of the pin is changed;

FIG. 7 is a sectional view of an example of a roller in another shape;

FIG. 8 is a cross-sectional view of a belt unit in case that the conveying path of a tractor paper is not curved.

DETAILED DESCRIPTION

According to one embodiment, a tractor comprises a pin belt, a pair of rotating units and a roller. The pin belt configured as an endless belt, which has a plurality of pins on the outer peripheral surface thereof, wherein the pins are respectively inserted into feeding holes formed on a tractor paper, and the pin belt rotates to convey the tractor paper. The pair of rotating units configured to rotate the pin belt. The roller, which is arranged between the pair of rotating units, with a groove on the outer peripheral surface thereof, wherein the front end of the pin is fitted into the groove, so that the front end of the pin is abutted against the groove to space between the outer peripheral surface of the pin belt and the outer peripheral surface of the roller.

FIG. 1 is a perspective view of a business machine 1 provided with the tractor 9 according to the embodiment. As shown in FIG. 1, the business machine 1 according to this embodiment comprises a main body unit 3, a keyboard 4 and a display 5.

The main body unit 3 and a printer unit (not shown) of a computer are accommodated in the frame 2 of the main body unit 3. A paper feeding port 7 for feeding a lengthwise tractor paper 6 (refer to FIG. 2) is formed at a position of the frame 2 opposite to the display 5. A tractor 9 for conveying the tractor paper 6 is accommodated in the frame 2. A paper outlet 8 is formed on the upper part of the frame 2 to feed out the tractor paper after it is fed into the frame 2 from the paper feeding port 7 and is printed. Further, another paper feeding port (not shown) is also configured below the display 5 in this embodiment. The other conveying unit (not shown) different from the tractor 9 uses the roller to convey the paper inserted by an operator from the paper feeding port below the display 5 and discharges the printed paper from the paper outlet 8.

FIG. 2 is a perspective view of the tractor 9. The tractor paper 6 printed by the printer unit of the business machine 1 is a strip-shaped paper on which a perforation (not shown) is formed along the width direction of the paper to be able to cut the paper apart and a plurality of the perforations are formed in the length direction of the strip-shaped paper at regular intervals.

A slip paper that a plurality of papers are laminated can be taken as an example of the tractor paper 6. A plurality of regularly spaced feeding holes 6b are formed at opposite sides of the tractor paper 6 along the length direction of the tractor paper 6. The tractor paper 6 is folded in a zigzag state and is placed at the side of the business machine 1.

The tractor 9 pulls out the tractor paper 6 from the top of the folded tractor paper and then successively conveys the tractor paper 6.

As shown in FIG. 2, the tractor 9 mainly comprises a pair of belt units 11 provided with pin belt (refer to FIG. 3), a guide unit 12 and a transmission shaft 13.

The transmission shaft 13 is configured across the pair of belt units 11. Moreover, the guide unit 12 is supported at the center of the transmission shaft 13 in the axial direction by a fixing device (not shown). Another transmission shaft (not shown) may also be configured across the pair of belt units 11.

The belt unit pair 11 is kept in parallel with one the other through the transmission shaft 13. The operator can change the space between the belt unit pair 11 by sliding either of the belt unit pair 11 along the transmission shaft 13. Thus, the operator can align the belt unit pair 11 with the opposite sides 6a of the tractor paper 6 according to the width of the tractor paper 6 so as to set the feeding holes 6b of the tractor paper 6 on the pin belt 14 (refer to FIG. 3) of the left and right belt units 11.

The guide unit 12 is arranged in the middle of the left and right belt units 11. The guide unit 12 supports, from the below, the substantially central part of the tractor paper 6 retained by the belt unit pair 11.

Thereby, it is able to prevent the application of a tension to the opposite sides 6a of the tractor paper 6 by the tractor paper 6 which is bent under its own weight.

The belt unit pair 11 and the guide unit 12 are both curved into a bow shape, and the tractor paper 6 is conveyed from the paper feeding port 7 to the paper outlet 8 (refer to FIG. 1) along the curved shape.

As shown in FIG. 2, each of the belt unit pair 11 comprises a base 15, a fixed cover 16, a movable cover 17 and a roller retainer 19. A shaft 13 runs through the roller retainer 19.

The movable cover 17 is rotationally supported on the base 15 of each of the belt unit pair 11 via a hinge unit 15b. Under the force applied by the operator manually, the movable cover 17 reciprocates between the vertical opening position represented by the dotted line shown in FIG. 2 and the horizontal closing position represented by the solid line shown in FIG. 2. The hinge unit 15b is configured on each of the belt unit pair 11 at a position outside the width direction of the tractor paper 6. Moreover, the rotation shaft of the hinge unit 15b is configured along the two ends of the tractor paper 6 in the width direction, that is, the opposite sides 6a of the tractor paper 6.

Therefore, the two movable covers 17 arranged on the belt unit pair 11 are opened like a butterfly formation door (double door) from the horizontal closing position toward the outside and upside of the width direction of the tractor paper 6 like the two movable covers 17 face each other in the width direction of the tractor paper.

The movable cover 17 is manually opened by the operator, as described above, to respectively fit the feeding holes 6b of the tractor paper 6 onto the pins 14b (refer to FIG. 3) of the pin belt 14s, thereby setting the tractor paper 6 on the pin belt 14.

FIG. 3 is a side-sectional view of the belt unit 11, a part of which is cut away and is not shown in FIG. 3.

The base 15 supports the fixed cover 16, the movable cover and the roller retainer 19. Moreover, the base 15 rotationally supports the rollers 20 and 20A (20) of a pair of rotating units that rotates the pin belt 14. An endless pin belt 14 is rotationally extended between the roller 20 and the roller 20A. The roller 20A rotates anticlockwise under the drive of a motor (not shown). When the roller 20A rotates anticlockwise under the drive of the motor, the pin belt 14 rotates in the direction indicated by an arrow shown in FIG. 3. The track that the pin belt 14 rotates in the direction indicated by the arrow shown in FIG. 3 is referred to as a rotation track of the pin belt 14. If the rotating unit is composed of at least one pair, more than two rotating units may be used, and the rotating unit is not limited to the roller 20, but may be formed in other shape.

The fixed cover 16 and the movable cover 17 are arranged to cover the upper portion of the base 15. The lower surface 16a of the fixed cover 16 and the lower surface 17a of the movable cover 17 are oppositely arranged at the positions that are a substantially fixed distance above the upper surface 15a of the base 15. A conveying path 10 for conveying the tractor paper 6 is created between the lower surfaces 16a and 17a and the upper surface of the base 15, and thus the tractor paper 6 is conveyed in the conveying path 10 as the pin belts 14 rotate.

The tractor 9 acquires the tractor paper 6 fed from the paper feeding port 7 (refer to FIG. 1) and conveys the tractor paper 6 in the conveying path 10. Moreover, the tractor 9 conveys the tractor paper 6 that is printed by a printer unit (not shown) in the conveying path 10 to the paper outlet 8 (refer to FIG. 1), and then discharges the printed tractor paper 6 from the paper outlet 8.

The pin belt 14 is made of elastomer or other flexible materials. The pin belt 14 comprises a strip shaped belt unit 14a having a fixed width and a plurality of pins that protrude, at given intervals, along a circumferential direction at the center part in the width direction of the belt unit 14a. In the middle of the conveying path 10 (that is, the part of the conveying path from a position nearby the lower portion of the movable cover 17 to a position nearby the lower portion of the fixed cover 16), the front end of the pin 14b protrudes more upwards than the upper portion 15a of the base 15. Therefore, the feeding holes 6b of the tractor paper 6 are caught by the pins 6b in the middle of the conveying path 10 so that the tractor paper 6 is driven in the conveying path 10 along with the rotation of the pin belts 14.

The roller retainer 19 between the rollers 20 and 20A supports a dual-torsion spring 21 (hereafter referred to as spring 21) having two coils. The coils of the spring 21 are respectively wound on the shafts 22 of the rollers 18. An elastic force is applied to the roller 18 by the spring 21 in a direction indicated by an arrow 40 (arrow direction) shown in FIG. 3 so that the roller 18 is abutted against the pin belt 41 and presses the pin belt 41 towards the arrow direction 40. In such a manner, the roller 18 curves the rotation track of the pin belt 14 towards the arrow direction 40. Moreover, the pin belt 14 is extended between the two rollers 18.

As shown in FIG. 3, a groove 18b and an outer edge 18a defining the groove 18b are configured on the periphery of the roller 18.

When the tractor paper 6 is fed to the roller 18 along with the rotation of the pin belt 14, the roller 18 and the pin belt 14 rotate synchronously to convey the tractor paper 6 out along the curved shape of the pin belt 14 in the conveying direction of the conveying path 10. Moreover, at the curved part of the pin belt 14, the pin belt 14 is conveyed while the pins 14b of the pin belt 14 are firmly fitted with the groove 18b of the roller 18.

In FIG. 3, a straight line 30 indicates the position where the central line 14c (refer to FIG. 5) of the pin 14b and the shaft 22 of the roller 18 are aligned.

The pin belt 14 and the tractor paper 6 on the pin belt 14 are most curved at the position of the straight line 30. Moreover, the pin 14b is most deeply fitted into the groove 18b on the straight line 30.

The problems existing in the conventional roller 18 (918) are described here in supplement. FIG. 4-1 and FIG. 4-2 are sectional views of the conventional roller 918 and pin belt 14 on a straight line 30. As shown in FIG. 4, a groove 918b and an outer edge 918a defining the groove 918b are configured on the periphery of the roller 918. FIG. 4-1 shows a roller 918 and a pin belt 14 between which no tractor paper 6 is inserted, and FIG. 4-2 shows a roller 918 and a pin belt 14 between which a tractor paper 6 is inserted.

As shown in FIG. 4-1, in the conventional roller 918, the depth d3 of the groove 918b is greater than the height (h) of the pin 14b. Thus, the outer edge 918a of the roller 918 is abutted against the belt unit 14a of the pin belt 14 to press the latter because the roller 918 is urged by the spring 21. Moreover, as shown in FIG. 4-2, if the tractor paper 6 is inserted between the roller 918 and the pin belt 14, the roller 918 is pushed back with the elasticity of the spring 21 towards the direction reverse to the arrow direction 40 by a distance equal to the thickness of the tractor paper 6. The outer edge 918a of the roller 918 is abutted against the tractor paper 6 to press the latter because the roller 918 is urged by the spring 21. In such a manner, the edges of the feeding holes 6b of the tractor paper 6 are pressed by the outer edge 918a of the roller 918 at the position nearby the curved part of the pin belt 14 where the roller 918 is located.

Especially, in the case where the tractor paper 6 is a slip paper such as an invoice paper composed of a plurality of papers laminated or a thick paper, the tractor paper 6 is hard to curve along the curved shape of the pin belt 14. Therefore, at the curved part, the tractor paper 6 is pressed into the roller 918 by the outer edge 918a of the roller 918 along the conveying direction and then conveyed. Therefore, a part of tractor paper 6 that is not completely curved is twisted and thus is apt to create wrinkle at the position nearby the blocked part of the paper 6 by the outer edge 918a of the roller 918.

In order to address this problem, it is considered to reduce the elastic constant of the spring 21, however, the application of this solution will also lead to a problem that the pin 14b may be apt to be slipped off the feeding hole 6.

Next, the roller 18 of the present embodiment is described. FIG. 5 is a sectional view of the roller 18 and the pin belt 14 of the embodiment on the straight line 30. As described in FIG. 3, the outer edge 18a and groove 18b are arranged on the periphery of the roller 18. That is, the outer periphery 18e of the roller 18 consists of the surface of the outer edge 18a and the bottom surface 18c of the groove 18b. Moreover, pins 14b are formed in a protrusion manner on the outer peripheral surface 14e of the belt unit 14a of the pin belt 14.

As shown in FIG. 5, the groove 18b of the roller 18 is abutted against the front end 14d of the pin 14b firmly fitted into the groove 18b on the straight line 30 (refer to FIG. 3). In such a manner, the roller 18 presses the pin belt 14 in the arrow direction 40 to curve the rotation track of the pin belt 14. Under this state, the roller 18 of this embodiment is located on the straight line 30 (refer to FIG. 3), and the surfaces of the outer edge 18a of the roller 18 and the belt unit 14a of the pin belt 14 are arranged such that they are spaced by a distance d4.

With the depth d3 of the groove 18b and the height h of the pin 14b, the distance d4 is here expressed by the following formula: d4=h−d3. Thus, the distance d4 set between the outer edge 18a of the roller 18 and the belt unit 14a must meet the following condition: d4=h−d3>0. Thus, the depth d3 of the groove 18b of the roller 18 just needs to meet the following condition: d3<h (Formula 1). That is, the distance d4 can be set between the surfaces of the outer edge 18a of the roller 18 and the belt unit 14a as long as the depth of the groove 18b of the roller 18 is smaller than the height h of the pin 14b.

Moreover, the distance d4 may also be greater than the thickness d5 of the tractor paper 6. In this case, the following formula must be met: d4=h−d3>d5. Thus, the depth d3 of the groove 18b of the roller 18 just needs to meet the following condition: d3<h−d5 (Formula 2).

As a more preferred embodiment, it is preferable that the distance d4 is set to be two times or three times the thickness (d5) of the tractor paper 6. For example, in the case where the distance d4 is set to be n times the thickness d5, the following formula is met: d4=h−d3≧n*d5. Thus, the depth d3 of the groove 18b of the roller 18 just needs to meet the following condition: d3≦h−n*d5 (Formula 3). Moreover, n may be a natural number, a fraction or a decimal fraction.

In such a manner, the distance d4 can be set between the surfaces of the outer edge 18a of the roller 18 and the belt unit 14a as long as the depth d3 of the groove 18b of the roller 18 meets at least one of the foregoing formulae (1)-(3). Moreover, as a preferred embodiment, the depth d3 of the groove 18b should be determined at more than a prescribed depth (threshold level) so that the pin 14b is not likely to be slipped off the groove 18b even the depth d3 of the groove 18b is decreased.

In the description above, the distance d4 is set based on the structure of the roller 18, but the distance d4 can also be set based on the structure of the pin belt 14.

FIG. 6 is a diagram showing an example of a pin belt 214 having a pin 214b whose height (h) is changed. As shown in FIG. 6, at least one of the foregoing formulae (1)-(3) can be met by adjusting the height h of the pin 214b. Moreover, the conventional roller 918 shown in FIG. 4-1 can be used as long as at least one of the formulae (1)-(3) is met.

Thus, in the tractor 9 of this embodiment, the distance d4 is set between the outer peripheral surface 18e of the roller 18 and the outer peripheral surface 14e of the belt unit 14a on the straight line 30 where the pin belt 14 is most curved. Therefore, the tractor paper 6 hardly twists even at a position where the tractor paper 6 is most curved and thus apt to twist.

The roller 18 may have other shapes that are not limited to the shapes shown in FIG. 5 and FIG. 6. FIG. 7 is a sectional view of an example of the roller 218 in another shape. As shown in FIG. 7, the groove 218b of the roller 218 consists of a curved surface, the bottom of which is formed by the central portion abutted against the front end 14d of the pin 14b. Shaped like this, the front end 14d of the pin 14b is stabilized on the central line 218c of the roller 218 to be prevented from moving transversely in the groove 218b of the roller 218, thus, the roller 218 can rotate easily and smoothly.

Chamfers 218d may be formed at the outer edge 218a of the roller 218. That is, as shown in FIG. 7, the chamfers 218d are formed on the outer peripheral surface of the roller 218 at the opposite sides along the rotational center line 22c of the roller 218. Moreover, the chambers 218d are formed into a circular shape along the outer peripheral surface 218e of the roller 218. Thus, the tractor paper 6 is hard to twist and thus does not generate a crease even after the tractor paper 6 is floated off the pin belt 14. Moreover, R-shaped chamfers are adopted as the chamfers 218d in FIG. 7; however, the chamfers 218d are not limited to this shape, as another example, the chamfers 218d may be C-shaped chamfers.

As stated above, in the tractor 9 of the above-described embodiment, the front end of the pin 14b is abutted against the groove 18b formed on the outer peripheral surface 18e of the roller 18 so as to curve the rotation track of the pin belt 14 and spaces the outer peripheral surface 18e of the roller 18 from the outer peripheral surface 14e of the belt unit 14a. The tractor paper 6 is not easily cause to twist or be creased with wrinkles at the curved part of the pin belt 14 where the roller 18 is abutted against the pin belt 14, thus preventing the occurrence of a crease.

Moreover, according to the tractor 9 of this embodiment, as the groove 18b of the roller 18 is abutted against the front end of the pin 14b to curve the rotation track of the pin belt 14, the pin belt 14 can be directly pressed by the roller 18. Typically, the friction coefficient of the pin belt 14 is greater than that of the tractor paper 6, thus, compared with the approach of pressing the tractor paper 6 by the roller 18, in the approach of directly pressing the roller 18 against the pin 14b of the pin belt 14 used herein, slipping is hard to be occurred on the pin belt 14. Thus, compared with the conventional art in which the tractor paper 6 is conveyed by pressing the pin 14b against the tractor paper 6, in the present embodiment, the pin belt 14 can be easily pressed by the roller 18, and the tractor paper 6 can be easily fed out.

In addition, as the pin 14b is abutted against the roller 18 in this case, the roller 18 may not be urged by the spring 21 in the arrow direction 40. Thus, the components of the tractor 9 can be decreased by directly supporting the shaft 22 of the roller 18 by the roller retainer 19.

Moreover, in the above embodiment, two rollers 18 are provided, but the number of the rollers may also be one (1) or more than two (2).

Although an exemplary miniaturized construction in which the tractor 9 is accommodated in the frame 2 is described in the embodiment, the upper portion of the tractor 9 may protrude outside the frame 2. Moreover, the installation position, the shape and the installation posture of the tractor 9 are not limited to those described in this embodiment. Further, the business machine 1 may be a printer not having a computer main body unit.

Moreover, in the description above, the belt unit 11 and the guide unit 12 are curved into a bow shape, and the conveying path 10 for conveying the tractor paper 6 is curved as well, however, this embodiment is also applicable even the conveying path 10 is not curved as shown in FIG. 8. FIG. 8 is a cross-sectional view of the belt unit 11 having a non-curved conveying path 10 for conveying the tractor paper. As shown in FIG. 8, the rotation track of the pin belt 14 may be linearly configured between the rollers 20 and 20A. For instance, the roller 18 is used to press the tractor paper 6 on the upper surface 15a of the base 15 to prevent the tractor paper from disjoining (floating off) from the conveying path 10 during conveyance, however, the function of the roller 18 is not limited to this.

Thus, even the conveying path 10 is not curved, like in the foregoing case, the tractor paper 6 does not twist easily at the part where the roller 18 is abutted against the pin belt 14, the pin belt 14 can be easily pressed by the roller 18 as well, and the tractor paper 6 can be fed out easily.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments of the embodiment may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments of the embodiment may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

1. A tractor, comprising:

a pin belt configured as an endless belt, which has a plurality of pins on the outer peripheral surface thereof, wherein the pins are respectively inserted into feeding holes formed on a tractor paper, and the pin belt rotates to convey the tractor paper;

a pair of rotating units configured to rotate the pin belt; and

a roller, which is arranged between the pair of rotating units, with a groove on the outer peripheral surface thereof, wherein the front ends of the pins are fitted into the groove, so that the front ends of the pins are abutted against the groove to space between the outer peripheral surface of the belt and the outer peripheral surface of the roller.

2. The tractor according to claim 1, wherein

the depth of the groove of the roller is set to be smaller than the height of the pin so as to space between the outer peripheral surface of the pin belt and the outer peripheral surface of the roller.

3. The tractor according to claim 1, wherein

the roller enables the front end of the pin fitted into the groove to be abutted against the groove, thereby curving the rotation track of the pin belt.

4. The tractor according to claim 1, wherein

the rotation track of the pin belt is linearly arranged between the pair of rotating units.

5. The tractor according to claims 2, wherein

the depth of the groove of the roller is set to be d, the height of the pin is set to be h, the thickness of the tractor paper is set to be d1, and a given number is set to be n; the outer peripheral surface of the pin belt and the outer peripheral surface of the roller are spaced by satisfying the following condition: d≦h−n*d1.

6. The tractor according to claims 1, further comprising:

a chamfer part, which is formed on the opposite sides of the outer peripheral surface of the roller along the rotational center line of the roller.

7. The tractor according to claims 1, wherein

the cross-section of the groove is formed with curved concavity shaped.

8. The tractor according to claim 2, wherein

the roller enables the front end of the pin fitted into the groove to be abutted against the groove, thereby curving the rotation track of the pin belt.

9. The tractor according to claim 2, wherein

the rotation track of the pin belt is linearly arranged between the pair of rotating units.

10. The tractor according to claims 3, wherein

the depth of the groove of the roller is set to be d, the height of the pin is set to be h, the thickness of the tractor paper is set to be d1, and a given number is set to be n; the outer peripheral surface of the pin belt and the outer peripheral surface of the roller are spaced by satisfying the following condition: d≦h−n*d1.

11. The tractor according to claims 4, wherein

the depth of the groove of the roller is set to be d, the height of the pin is set to be h, the thickness of the tractor paper is set to be d1, and a given number is set to be n; the outer peripheral surface of the pin belt and the outer peripheral surface of the roller are spaced by satisfying the following condition: d≦h−n*d1.

12. A printer, comprising:

a tractor claimed in the claims 1; and

a printer unit configured to print on the tractor paper conveyed by the tractor.