JP2005324402A - Thermal transfer printer and sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer printer and a sheet feeder which prevent the generation of deflection at a pinch roller because of an energizing force and are superior in workability at the time of setting the pinch roller. <P>SOLUTION: There are set a paper feed roller 11 and the pinch roller 21 for supplying a sheet 51 to a printing part by rotating while holding the sheet 51 therebetween, and an ink ribbon 31 and a thermal head 32 arranged at the printing part. The pinch roller 21 has its middle part made a small diameter part 23 and is equipped with large diameter parts 22 continuously with both ends of the small diameter part 23. Each of the large diameter parts 22 at both ends of the pinch roller 21 is pressed in a direction of the sheet feed roller 11 to contact the sheet feed roller 11. The large diameter part 22 extends up to an end part of the pinch roller 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal transfer printer and a paper feeding device provided with a paper feeding roller and a pinch roller that sandwich paper and supply it to a printing unit.

  Conventional thermal transfer printers and other printers generally include a paper feed roller 111 that is rotationally driven and a pinch roller 121 that is driven by the paper feed roller 111 as shown in FIG.

  The paper feed roller 111 and the pinch roller 121 are usually configured by a metal shaft. However, when the surface of the paper feed roller 111 is configured by a metal, a grip for reliably transporting the paper. A portion 112 is provided. In many cases, the grip portion 112 is configured by a knurling that is a mesh pattern unevenness.

  The grip portion 112 protrudes from the other surface of the paper feed roller 111, but in order to prevent the grip portion 112 from contacting the pinch roller 121, there is a gap between the pinch roller 121 and the paper feed roller 111. The large diameter part 122 which protrudes from the other part which forms is provided. The conventional large-diameter portion 122 is partially formed at a position away from the end of the pinch roller 121 by a certain distance, as shown in FIG. In practice, in order to form the large-diameter portion 121, the large-diameter portion 122 is protruded by cutting the three ends of the pinch roller 121 at both ends and the middle portion into the small-diameter portion 123.

  The small diameter portions 123 at both ends of the pinch roller 121 are pressed by the bearing 126 and urged toward the paper feed roller 111.

Patent Document 1 discloses a printer including such a paper feed roller and a pinch roller.
JP-A-9-240873

  In the conventional pinch roller 121 described above, two large diameter portions 122 are provided at positions spaced apart from both end portions, both ends are set as small diameter portions 123, and the small diameter portion 123 is urged by a bearing 126. Since there is a gap G between the small-diameter portions 123 at both ends and the paper feed roller 111 as shown in FIG. 5, the small-diameter portions 123 at both ends of the pinch roller 121 are moved by the urging force from the bearing 126. It bends in the direction of 111.

  Accordingly, the small diameter portion 123 at the center of the pinch roller 121 bends away from the paper feed roller 111 with the large diameter portion 122 as a fulcrum, and the gap between the pinch roller 121 and the paper feed roller 111 increases. Accordingly, there is a problem that the pinch roller 121 may not be able to sufficiently press the paper against the paper feed roller 111.

  Further, when the pinch roller 121 is assembled, the small-diameter portion 123 at one end of the pinch roller 121 is first attached to the bearing 126. When the pinch roller 121 is urged by the bearing 126, there is a gap G. The tip of the small-diameter portion 123 attached with the large-diameter portion 122 as a fulcrum moves so as to contact the paper feed roller 111. As a result, the end of the pinch roller 121 on the opposite side which has not yet been mounted is lifted, and there is a problem that workability in assembling the pinch roller 121 is poor.

  Accordingly, the present invention has been made to solve the above-described problems, and there is provided a thermal transfer printer and a paper feeding device that are free from bending of the pinch roller due to the urging force and that are excellent in workability during assembly. The purpose is to provide.

  According to the thermal transfer printer according to the present invention, the thermal transfer includes a paper feed roller and a pinch roller that sandwich and rotate a sheet to be supplied to the print unit, and an ink ribbon and a thermal head disposed in the print unit. In the printer, the pinch roller has an intermediate portion as a small diameter portion, a large diameter portion is provided continuously at both ends of the small diameter portion, and the large diameter portions at both ends of the pinch roller are respectively Pressed in the direction of the paper feed roller and in contact with the paper feed roller, the large diameter portion extends to the end of the pinch roller, the paper feed roller is made of metal, and the paper feed roller The at least part of the portion facing the small diameter portion of the pinch roller is provided with an uneven grip portion.

  According to the paper feeding device based on the present invention, a paper feeding device including a paper feeding roller and a pinch roller that sandwiches and rotates the paper and supplies it to the printing unit, the pinch roller having an intermediate portion thereof A large diameter portion is provided continuously at both ends of the small diameter portion, and the large diameter portion is pressed in the direction of the paper feed roller and is in contact with the paper feed roller.

  Preferably, in the paper feeding device, the large diameter portion extends to an end portion of the pinch roller.

  More preferably, in the paper feeding device, the paper feeding roller is made of metal, and an uneven grip portion is provided on at least a part of the portion of the paper feeding roller facing the small diameter portion of the pinch roller. ing.

  According to the thermal transfer printer and the paper feeding device according to the present invention, the large-diameter portion of the pinch roller is urged to contact the paper feeding roller. In addition, one of the pinch rollers is not lifted and workability is not deteriorated.

  Hereinafter, a thermal transfer printer and a paper feeding device thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 is a side view showing the structure of the main part of the thermal transfer printer in this embodiment, FIG. 2 is a front view showing a paper feed roller and a pinch roller, and FIG. 3 is a diagram showing the paper feed roller and the pinch roller. FIG. 4 is a perspective view showing the assembled state, and FIG. 4 is an enlarged view showing ends of the paper feed roller and the pinch roller.

  As shown in FIGS. 1 and 2, the thermal transfer printer according to the present embodiment has a paper feed roller 11 and a pinch roller 21 that sandwich and rotate the paper 51 and supplies it to the print unit, and the print unit. An ink ribbon 31 and a thermal head 32 are provided. The pinch roller 21 has an intermediate portion as a small diameter portion 23, and a large diameter portion 22 is provided continuously at both ends of the small diameter portion 23, and the large diameter portion 22 is pressed in the direction of the paper feed roller 11. In contact with the paper feed roller 11. The large diameter part 22 extends to the end of the pinch roller 21. The paper feed roller 11 is made of metal, and an uneven grip portion 12 is provided on a part of the paper feed roller 11 facing the small diameter portion 23 of the pinch roller 21.

  First, an outline of the structure of the thermal transfer printer of this embodiment will be described with reference to FIG. A paper feed roller 1 that feeds the paper 51 in the paper feeding direction is provided. The paper feed roller 1 rotates in a certain direction, and applies a driving force to the paper 51 on the bed 3 located below the paper feed roller 1 in the paper feed direction (right direction in FIG. 1).

  The paper 51 is guided to the upper surface of the bed 3 and fed horizontally. The pinch roller 21 and the paper feed roller 11 are located in the feeding direction. The pinch roller 21 is a metal shaft, and its surface is finished smoothly. A driving device such as a motor for directly driving the pinch roller 21 is not provided, and the pinch roller 21 rotates following the rotation of the paper feed roller 11.

  A motor is connected to the paper feed roller 11 through a gear (not shown), and is driven to rotate. The paper feed roller 11 is also composed of a metal shaft similar to the pinch roller 21, but a grip portion 12 that acts as an anti-slip is provided on a part of the surface of the paper feed roller 11 to reliably convey the paper 51. (See FIG. 2). This anti-slip is composed of a knurled mesh pattern formed on the surface of the shaft.

  A thermal head 32 and an ink ribbon 31 are provided in the printing unit on the downstream side of the paper feed roller 11 and the pinch roller 21. The thermal head 32 has a heating portion on the lower surface of the tip thereof, and sublimates the ink on the ink ribbon 31 and transfers it to the paper. A platen roller 33 is provided below the thermal head 32 so as to be in contact with the lower surface of the paper 51 pressed by the thermal head 32.

  Here, the thermal transfer printer of this embodiment is a so-called sublimation printer mainly used for photographic printing. The ink ribbon 31 is composed of three colors of yellow, magenta, and cyan, and an overcoat. A total of four types of areas are configured to repeat.

  Printing in the printing unit is performed when the paper 51 is once sent to the most downstream side in the paper feeding direction and the paper 51 returns in the direction opposite to the paper feeding direction (hereinafter, this direction is referred to as the return direction). At this time, the ink ribbon 31 is also fed in the same direction as the paper 51 at the same speed, heated by the thermal head 32, and the ink is transferred to the surface of the paper 51. As described above, the ink ribbon 31 includes four types of regions, and the ink or overcoat of one region is transferred to the paper 51 by one movement in the return direction. The image is completed on the paper 51 by repeating this four times (reciprocating four times).

  In order to prevent the rear end side (left end in FIG. 1) of the paper 51 from coming into contact with the paper feed roller 1 when the paper 51 is fed in the return direction, the inclined guide plate 46 is placed so as to cover the paper feed roller 1. Is provided.

  As described above, the paper feed roller 11 and the pinch roller 21 according to this embodiment convey the paper 51 in two directions, ie, the paper feeding direction and the return direction.

  Next, the structure of the paper feed roller 11 and the pinch roller 21 will be described in detail. As shown in FIG. 2, the paper feed roller 11 and the pinch roller 21 are provided so as to face each other in the vertical direction. As described above, the large-diameter portion 22 that is slightly thicker than the small-diameter portion 23 at the intermediate portion is formed at both ends of the pinch roller 21.

  The large diameter part 22 extends to the end of the pinch roller 21. In the process of manufacturing the pinch roller 21, the intermediate portion is cut while leaving the large diameter portion 22, but the large diameter portion 22 extends to the end of the pinch roller 21, so that cutting can be completed only once. It is possible to excel in productivity.

  A grip portion 12 is provided at a portion of the paper feed roller 11 corresponding to the small diameter portion 23 of the pinch roller 21. The grip portion 12 is constituted by a knurled mesh pattern, but its tip slightly projects outward from the other surface of the paper feed roller 11 as shown in FIG. Since the pinch roller 21 is provided with the small-diameter portion 23, the tip of the grip portion 12 and the pinch roller 21 can be prevented from contacting each other.

  The large diameter portions 22 at both ends of the pinch roller 21 are urged in the direction of the paper feed roller 11 by bearings 26. The structure of the bearing 26 will be described later. Thereby, the large diameter portion 22 of the pinch roller 21 is always in contact with the paper feed roller 11. At this time, in the present embodiment, the large-diameter portion 22 of the pinch roller 21 is urged, and the urged portion is in contact with the paper feed roller 11, so that the fulcrum and the force point coincide. As a result, it is possible to prevent the pinch roller 21 from being bent due to the fulcrum and the power point being shifted as in the conventional pinch roller. Thereby, the gap between the pinch roller 21 and the paper feed roller 11 is always kept constant, and the paper 51 can be conveyed stably.

  As shown in FIG. 3, the bearing 26 is attached to a side surface of a frame 41 constituting a part of the housing. The bearing 26 is configured to have a front-view shape, and a shaft 27 passes through a corner portion thereof, and is rotatable about the shaft 27. A synthetic resin sliding member 28 having a semicircular inner peripheral surface is provided at the tip of the bearing 26, and the outer peripheral surface of the large-diameter portion 22 of the pinch roller 21 is provided on the inner peripheral surface of the sliding member 28. The surfaces are in contact.

  A spring 29 is provided at the lower end of the bearing 26 and applies a biasing force in the direction indicated by the arrow in FIG. This urging force is applied as a downward force (in the direction of the paper feed roller 11) to the pinch roller 21 with the shaft 27 as a fulcrum. The same bearings 26 are provided at both ends of the pinch roller 21, thereby urging the large diameter portions 22 at both ends of the pinch roller 21 in the direction of the paper feed roller 11.

  When the pinch roller 21 is assembled, both end portions of the pinch roller 21 are sequentially locked with respect to the pair of bearings 26. When one end of the pinch roller 21 is locked to the bearing 26, a biasing force is applied only to that end, but in the pinch roller 21 of the present embodiment, the portion to which the biasing force is applied is the large-diameter portion 22. Since the large-diameter portion 22 is always in contact with the paper feed roller 11, the opposite end portion of the pinch roller 21 that is not yet locked is not lifted. Thereby, the assembly | attachment operation | work of the pinch roller 21 can be performed smoothly, and it is excellent in workability | operativity.

  Further, since the large diameter portion 22 of the present embodiment has a larger width than the large diameter portion of the conventional pinch roller, the change in the outer shape due to wear is reduced, and the product life can be extended. .

  In the above-described embodiment, the case where the large-diameter portion 22 extends to the end of the pinch roller 21 has been described. However, if the portion to which the urging force is applied by the bearing 26 is the large-diameter portion 22, the pinch There may be a small diameter portion at the end of the roller 21. However, as described above, when the large-diameter portion 22 extends to the end portion of the pinch roller 21, the number of times of cutting can be minimized.

  Furthermore, although the thermal transfer printer has been described in the above embodiment, the paper feeding device can be applied to other image forming apparatuses such as an ink jet printer.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

It is a side view which shows the structure of the principal part of the thermal transfer printer in embodiment based on this invention. It is a front view which shows the paper feed roller and pinch roller in embodiment based on this invention. It is a perspective view which shows the state which assembled | attached the paper feed roller and pinch roller in embodiment based on this invention. It is an enlarged view which shows the edge part of the paper feed roller and pinch roller in embodiment based on this invention. It is a front view which shows the conventional paper feed roller and pinch roller.

Explanation of symbols

  11 Paper feed roller, 12 Grip part, 21 Pinch roller, 22 Large diameter part, 23 Small diameter part, 31 Ink ribbon, 32 Thermal head, 51 Paper.

Claims (4)

A thermal transfer printer comprising a paper feed roller and a pinch roller that sandwich and rotate a sheet to be supplied to a print unit, and an ink ribbon and a thermal head disposed in the print unit, wherein the pinch roller is in the middle The small-diameter portion is provided, and a large-diameter portion is provided continuously at both ends of the small-diameter portion, and the large-diameter portions at both ends of the pinch roller are respectively pressed in the direction of the paper feed roller, and the paper A portion that is in contact with the feed roller, the large diameter portion extends to an end of the pinch roller, the paper feed roller is made of metal, and a portion of the paper feed roller that faces the small diameter portion of the pinch roller A thermal transfer printer in which at least a part of is provided with an uneven grip portion. A paper feeding device provided with a paper feeding roller and a pinch roller that sandwiches and rotates the paper and supplies it to the printing unit,
The pinch roller has an intermediate portion as a small diameter portion, and a large diameter portion is provided continuously at both ends of the small diameter portion,
The paper feeding device in which the large diameter portions at both ends of the pinch roller are pressed in the direction of the paper feeding roller and are in contact with the paper feeding roller.   The paper feeding device according to claim 2, wherein the large diameter portion extends to an end of the pinch roller.   The paper feed roller is made of metal, and an uneven grip portion is provided on at least a part of the paper feed roller facing the small diameter portion of the pinch roller. The paper feeding device described.

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