Patent Application
20120298711
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.
Embodiments described herein relate to a tractor and a printer which is equipped with the tractor.
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.
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.
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
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
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
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
As shown in
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
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
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
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
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
As shown in
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
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.
As shown in
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.
As shown in
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.
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
Chamfers 218d may be formed at the outer edge 218a of the roller 218. That is, as shown in
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
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-116026 | May 2011 | JP | national |
| 2012-037865 | Feb 2012 | JP | national |
