JP4299566B2 - Thermal printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal printer, and more particularly to a thermal printer having a tension adjustment mechanism for a printing ribbon.
[0002]
[Prior art]
The thermal printer uses a thermal head that has a length corresponding to the width of the paper for one line, holds the paper and printing ribbon between the thermal head and the platen roller, and drives the thermal head to apply to the printing ribbon. It is a printer that transfers the printed ink onto paper according to the principle of thermal transfer and prints it. The printing ribbon used in the thermal printer has a width corresponding to the width of the paper, passes from the supply roll on the upstream side of the thermal head between the thermal head and the platen roller, and is wound on the downstream side of the thermal head. It is wound on a roll. As such a printing ribbon, an ink material applied on one side of a plastic film is used.
[0003]
As described above, the printing ribbon used in the thermal printer has a width corresponding to the width of the paper to be printed, and is heated by the thermal head and wound around the winding roller as the printing operation progresses. In this winding process, wrinkles are generated in the printing ribbon, and when the wrinkles reach the printing portion where the thermal head is disposed, black lines may be generated corresponding to the wrinkles or printing omission may occur.
[0004]
In order to prevent wrinkling of the printing ribbon, a mechanism for applying tension to the printing ribbon is provided in the ribbon winding path between the supply roll and the winding roll. For example, when wrinkles of a printing ribbon occur in an oblique streak from one side to the other side in the width direction of the printing ribbon, the tension applied to one end in the width direction of the printing ribbon is applied to the other end. By using a tension shifting mechanism that makes the tension larger than the applied tension, the generation of wrinkles can be suppressed.
[0005]
Patent Document 1 discloses a ribbon wrinkle removing roller in which rubber feet are provided at both ends of the roller. Then, the ink ribbon is sandwiched between the ribbon wrinkle removing roller and the auxiliary plate, and the elastic deformation of the rubber feet at both ends of the ribbon wrinkle removing roller gives tension to the outer side in the width direction of the ink ribbon, thereby removing the vertical wrinkles generated in the ink ribbon It is described to be removed.
[0006]
[Patent Document 1]
Japanese Utility Model Publication No. 5-85654
[Problems to be solved by the invention]
When the thermal printer becomes large and the width of the paper increases to some extent, the generation of wrinkles on the printing ribbon becomes complicated. For example, an oblique streak that goes from one side in the width direction of the printing ribbon toward the center side and an oblique streak that goes from the other side in the width direction toward the center side occur simultaneously. In this way, a plurality of wrinkles with different muscle running directions may occur at the same time, the strength may be different between one side wrinkle and the other side wrinkle, and only one side wrinkle may occur. .
[0008]
In the rubber foot tension mechanism described in Patent Document 1, tension is applied to the ribbon for printing simply by pressing the rubber foot against the auxiliary plate. Therefore, tension is adjusted, particularly at both ends of the ribbon in the width direction. It is difficult to make adjustments that differ, and it is impossible to meticulously cope with the generation of various wrinkles. Also, it cannot cope with printing ribbons of various widths.
[0009]
An object of the present invention is to provide a thermal printer capable of solving the problems of the prior art and finely dealing with the generation of wrinkles in a printing ribbon.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a thermal printer according to the present invention includes a printing ribbon having a width corresponding to the width of the paper, a thermal head, and a printing ribbon held between the thermal head and the paper. A platen roller that feeds the paper in accordance with the printing operation and sends the printing ribbon as the paper is fed, and a ribbon winding that is provided on the downstream side of the thermal head and winds up the printing ribbon that is fed according to the movement of the platen roller. A tension adjusting mechanism for a printing ribbon provided in a ribbon winding path between the thermal take-up mechanism and the thermal head and the ribbon winding mechanism, wherein the printing ribbon comes into contact with both ends of the width of the printing ribbon. Adjust the difference between the ribbon path length at the center of the ribbon width for printing and the ribbon path length at both ends of the width by varying the amount to spread both ends of the width A tension adjusting mechanism having a mutually independent two push movable spread member that, characterized in that it comprises a.
[0011]
With the above configuration, the tension adjusting mechanism has a pair of spreading members that can change the amount of spreading the printing ribbon by contacting the both ends of the width of the printing ribbon. Therefore, the amount of expansion can be varied in accordance with the wrinkle generated on the printing ribbon, and the generation of wrinkles can be dealt with finely.
[0012]
Moreover, it is preferable that the tension adjusting mechanism has a pair of spreading members that can independently vary a spreading amount on one side of the width of the printing ribbon and a spreading amount on the other side. With the above configuration, even when the wrinkle pattern generated on one side of the width of the printing ribbon is different from the wrinkle pattern generated on the other side, the amount of spreading can be varied independently, thereby generating various wrinkles. It is possible to deal with meticulously.
[0013]
Further, each of the spreading members of the tension adjusting mechanism includes a ribbon contact side having a width corresponding to the ribbon width, a rotation center portion that is provided eccentrically from the ribbon contact side at a center portion of the width, A rotation amount setting portion for setting the rotation amount of the ribbon contact side portion, and a plate-like spreading member having a rotation center portion of each spreading member provided at a central portion in the width direction of the ribbon feeding path It is preferable that it is rotatably attached around the center of rotation.
[0014]
By the said structure, it has a pair of plate-shaped expansion member which can be rotated around the rotation center provided in the center part of the width direction of a ribbon feed path | route. Therefore, by turning one spreading member around the center of rotation clockwise, for example, and turning the other spreading member counterclockwise, the ribbon path length at both ends becomes the ribbon at the center of the width of the printing ribbon. It can be adjusted longer than the path length. Also, since the rotation amount of one spreading member and the rotation amount of the other spreading member can be set independently, the ribbon path length on one side and the ribbon path length on the other side of the width of the printing ribbon Can be adjusted independently.
[0015]
In addition, the tension adjustment mechanism includes a rotation amount scale provided on one side of the ribbon take-up path, and a mark portion provided at one end of the spread member corresponding to the rotation amount scale as viewed from the rotation center portion of each spreading member. It is preferable that the rotation amount is set using a rotation amount scale and a mark portion of each spreading member. With the above configuration, the rotation amount of each spreading member can be set on one side of the ribbon winding path, and a fine response to the generation of wrinkles in the printing ribbon becomes easier.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic perspective view of the thermal printer 10. The thermal printer 10 is a printer that performs printing on a paper 12 supplied by a paper supply unit (not shown) on the principle of thermal transfer. The thermal printer 10 includes a printing ribbon 14, a thermal head 16, and a platen roller 18, and the paper 12 and the printing ribbon 14 are held between the thermal head 16 and the platen roller 18. The thermal printer 10 also includes a supply roll 20 that supplies the printing ribbon 14 and a take-up roll 22 that winds up the printing ribbon 14. The thermal printer 10 further includes a first tension bar 24 and a second tension bar 24 that change the direction of the winding path while applying an appropriate tension to the printing ribbon in the winding path between the supply roll 20 and the winding roll 22. A tension bar 26 and a tension adjusting mechanism 30 are provided. These components are arranged and attached to a frame (not shown), and the operation of each component is controlled by a control unit (not shown).
[0017]
The thermal head 16 is a heater element array in which a plurality of heating elements are arranged on one line, and is formed on a ceramic plate, for example. The ceramic plate may be mounted on a metal plate that serves as both reinforcement and heat dissipation, such as an aluminum plate. The length of one line corresponds to the printing width of the paper, and for example, a length of about 200 mm can be used. The arrangement pitch of each heating element is an element that determines the fineness of printing, and can be set to, for example, about 12 dots / mm. Each heating element is energized and cut off in response to a print command under the control of a control unit (not shown).
[0018]
The platen roller 18 is a roller disposed facing the thermal head 16 and is pressed against the thermal head 16 with a predetermined pressure by an urging mechanism (not shown). The urging mechanism can also be provided on the thermal head 16 side. The platen roller 18 holds the paper 12 and the printing ribbon 14 in between, and rotates to feed the paper 12 in the direction of the arrow shown in FIG. 1, and together with the feeding of the paper 12, the printing ribbon 14 also shows the arrow shown in FIG. Has a function to send in the direction. The platen roller 18 is rotated by a motor (not shown) under the control of a control unit (not shown).
[0019]
The printing ribbon 14 is a long plastic film having a width corresponding to the width of the paper, and an ink material is applied to one side surface thereof. In the above example, one having a maximum width of about 220 mm and a length of about 500 m can be used. For example, a plastic film having a thickness of 3 to 10 μm can be used, and a resin ink, a wax resin ink or a wax ink having a thickness of 3 to 10 μm can be used as an applied ink material. In the thermal printer 10, the printing ribbon 14 is disposed so that the side on which the ink material is applied faces the paper 12.
[0020]
The supply roll 20 is a roll formed by winding a printing ribbon 14 not yet used for printing around a roller a plurality of times, and is arranged on the upstream side of the thermal head 16. The take-up roll 22 is a roller arranged on the downstream side of the thermal head 16 and is supplied from the supply roll 20 and takes up the printing ribbon 14 that has passed between the thermal head 16 and the platen roller 18 in a roll shape. It is. The urging means (not shown) applies an urging force to the supply roll 20 and the take-up roll 22 in the direction of winding the printing ribbon 14 together. Therefore, when the platen roller 18 rotates and feeds the paper 12, the printing ribbon 14 is also pulled in the winding direction by the urging force applied to the supply roll 20 and the take-up roll 22, and is shown in FIG. It is sent in the direction of the arrow and is taken up by the take-up roll 22.
[0021]
The first tension bar 24 is a member disposed in a winding path between the supply roll 20 and the thermal head 16 and can be formed of, for example, a round bar. The first tension bar 24 has a function of changing the direction of the winding path of the printing ribbon 14 and a function of applying an appropriate tension to the printing ribbon 14. The first tension bar 24 may be a fixed round bar or may be rotatable. The angle formed between the axial direction of the first tension bar 24 and the feeding direction of the printing ribbon 14 may be a right angle, or a mechanism capable of changing the angle may be provided. For example, by tilting the printing ribbon 14 by an appropriate angle, the tension applied to one end in the width direction of the printing ribbon 14 can be made larger than the tension applied to the other end. Wrinkles of the printing ribbon 14 that occur obliquely from one end to the other end in the width direction can be suppressed.
[0022]
The second tension bar 26 is a member that is disposed in a winding path between the thermal head 16 and the winding roll 22 and can be formed of, for example, a round bar. The second tension bar 26 mainly has a function of changing the direction of the winding path of the printing ribbon 14.
[0023]
The tension adjusting mechanism 30 is disposed on the downstream side of the thermal head 16, that is, in the winding path between the thermal head 16 and the winding roll 22, and comes into contact with both ends of the width of the printing ribbon 14, respectively. 14 is a mechanism that varies the amount by which 14 is spread. Specifically, it is composed of a pair of spreading members 30a, 30b, and each of the spreading members 30a, 30b is respectively arranged around the rotation center provided at the center in the width direction in the winding path of the printing ribbon 14. Mounted rotatably.
[0024]
FIG. 2 is a plan view of the spreading member 30a and also shows a corresponding side view. The spreading member 30 a is a rectangular plate-like member, and the dimension in the longitudinal direction is set longer than the width of the printing ribbon 14. Long holes 60 and 62 are provided at both ends in the width direction, and a hole 66 is provided at the center. One side in the longitudinal direction is a contact side 68 with the printing ribbon, and the end surface of the contact side 68 is processed smoothly. If this end face is not processed smoothly, the printing ribbon 14 may be scratched or wrinkled on the printing ribbon 14. This end face can also be formed smoothly by bending a spread member 30a, which is a plate-like member, into a double layer. As the material of the spreading member 30a, for example, stainless steel having a plate thickness of 0.5 mm can be used. Moreover, cold-rolled steel that has been plated may be used, or plastic may be used. The other spreading member 30b can have the same shape.
[0025]
FIG. 3 is a detailed peripheral view when the tension adjusting mechanism 30 is configured by arranging a pair of spreading members 30 a and 30 b in the winding path of the printing ribbon 14. FIG. 3 shows a view from the back side of the thermal head. A thermal head and a second tension bar are arranged on the back side of the thermal head mounting base 50 (not shown in FIG. 1) shown in this figure. Yes. The thermal head mounting base 50 is provided with a rotation hole into which the rotation shaft 52 is fitted at the center in the width direction in the winding path of the printing ribbon 14, and rotation stop screws 54 and 56 are fixed to both sides of the rotation hole. A pair of screw holes is provided. The relative positional relationship between the rotation hole and the pair of screw holes is the same as the relative relationship between the central hole of each spreading member and the long holes on both sides.
[0026]
The hole of the center part of the spreading member 30a is made to coincide with the position of the hole into which the rotary shaft 52 of the thermal head mounting base 50 is fitted, and further, the hole of the center part is made to coincide by overlapping the spreading member 30b. The rotating shaft 52 is fitted. Accordingly, the pair of spreading members 30a and 30b are supported and arranged so as to be rotatable around the rotation shaft 52. If the rotation angle is within a certain range, the overlapping portions of the elongated holes 60 and 62 provided at both ends of each of the spreading members 30a and 30b are used, and each of the spreading members 30a and 30 b can be fixed to the thermal head mounting base 50.
[0027]
The thermal head mounting base 50 is provided with a scale 58 for quantitatively measuring the rotation angle of each of the spreading members 30a and 30b. The scale 58 is provided at a position corresponding to the rectangular corners 74a and 74b of the spreading members 30a and 30b. Since the movement of each of the spreading members 30 a and 30 b is symmetrical around the rotation axis 52, the scale 58 may be provided on either side as viewed from the rotation axis 52.
[0028]
The operation of the tension adjusting mechanism 30 having such a configuration will be described. In the initial state, the pair of spreading members 30a and 30b are fixed by the rotation-preventing screws 54 and 56 in a state where they are not overlapped and are just overlapped. At this time, the corners 74 a and 74 b of the spreading members 30 a and 30 b coincide with each other and correspond to the origin of the scale 58. When printing is performed by operating the thermal printer 10 in this state, when a printing defect due to wrinkling of the printing ribbon 14 occurs, the rotation-preventing screws 54 and 56 are loosened, and the spread members 30a, 30a, While observing the amount of movement of the corner portions 74a and 74b of 30b, the spreading members 30a and 30b are rotated around the rotation shaft 52 in a direction to suppress the generation of wrinkles, and the rotation-preventing screws 54 and 56 are tightened to press each pushing member. The rotation angle of the spreading members 30a and 30b is set. The rotation of each of the spreading members 30a and 30b around the rotation axis 52 can be performed independently.
[0029]
The setting of the rotation direction and rotation angle for each of the spreading members 30a and 30b for suppressing the generation of wrinkles can be summarized in a lookup table or the like by accumulating experimental data. Qualitatively, it can be set as follows according to the mode of wrinkle generation. It should be noted that the manner of wrinkle generation can be distinguished by the angle formed by the black line or the like generated in printing with respect to the feeding direction of the printing ribbon 14.
[0030]
In the first wrinkle generation mode, an oblique streak from the one side in the width direction of the printing ribbon to the center side and an oblique streak from the other side in the width direction to the center side occur simultaneously. Is the case. At this time, it can be considered that sagging occurs from the center in the width direction of the printing ribbon to both ends. Therefore, the one spreading member 30a is rotated in one direction, for example, clockwise while the rotation shaft 52 is the rotation center, and the other spreading member 30b is rotated in the other direction, for example, counterclockwise.
[0031]
By doing so, the one spreading member 30a rotated in the clockwise direction comes into contact with the one end 72 in the width direction of the printing ribbon 14 so as to spread the printing ribbon 14 and rotates in the counterclockwise direction. The other spreading member 30b contacts the printing ribbon 14 so as to spread at the other end 70 in the width direction of the printing ribbon 14. In the central portion of the printing ribbon 14 in the width direction, any of the spreading members can be made hardly to contact the printing ribbon 14. Therefore, the ribbon path length at the center portion in the width direction of the printing ribbon 14 can be minimized, and the ribbon path length at both ends in the width direction can be increased. In other words, both ends in the width direction of the printing ribbon can be expanded more than the center portion, and the printing ribbon can be extended from the center portion toward both ends, and from the center portion in the width direction of the printing ribbon. Less sagging at both ends. In this way, it is possible to suppress the simultaneous occurrence of the diagonal streak from the one side in the width direction of the printing ribbon toward the center and the slant wrinkle from the other side in the width direction toward the center. .
[0032]
The second generation of wrinkles is a case where wrinkles are generated in the form of diagonal streaks from one side to the other side in the width direction of the printing ribbon. At this time, the pair of spreading members 30a and 30b may be rotated in either direction around the rotation shaft 52 while being stacked without deviation. For example, in FIG. 3, when wrinkles are generated because one end 72 in the width direction of the printing ribbon 14 has a larger slack than the other end 70, the pair of spreading members 30a and 30b in FIG. Rotate clockwise to make the ribbon path length at one end 72 longer than the ribbon path length at the other end 70. Similarly, when the slack of the other end 70 in the width direction of the printing ribbon 14 is larger than that of the one end 72, the printing ribbon 14 rotates counterclockwise. In this way, it is possible to suppress the occurrence of wrinkles that are formed in diagonal stripes from one side to the other side in the width direction of the printing ribbon.
[0033]
As described above, the setting of the rotation angle of the pair of spreading members 30a and 30b, that is, the setting of the amount of spreading of the printing ribbon can be varied independently. Is possible.
[0034]
【The invention's effect】
With the thermal printer according to the present invention, it is possible to meticulously cope with the generation of wrinkles on the printing ribbon.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a thermal printer according to an embodiment of the present invention.
FIG. 2 is a side view corresponding to a plan view of a spreading member according to an embodiment of the present invention.
FIG. 3 is a detailed view of the periphery of the tension adjustment mechanism in the embodiment according to the present invention.
[Explanation of symbols]
10 Thermal Printer, 12 Paper, 14 Printing Ribbon, 16 Thermal Head, 18 Platen Roller, 20 Supply Roll, 22 Take-up Roll, 24 First Tension Bar, 26 Second Tension Bar, 30 Tension Adjustment Mechanism, 30a, 30b Push Spreading member, 50 thermal head mounting base, 52 rotary shaft, 54, 56 rotation set screw, 58 scale, 60, 62 oblong hole, 66 hole, 68 contact side, 70 other end, 72 one end, 74a, 74b corner.

Claims (4)

A printing ribbon having a width corresponding to the width of the paper;
Thermal head,
A platen roller that holds the printing ribbon between the thermal head and the paper, sends the paper in accordance with the printing operation of the thermal head, and sends the printing ribbon as the paper is fed;
A ribbon take-up mechanism that is provided on the downstream side of the thermal head and winds up a print ribbon sent in accordance with the movement of the platen roller;
A tension adjustment mechanism for the printing ribbon provided in the ribbon winding path between the thermal head and the ribbon winding mechanism, and the amount of the printing ribbon that pushes the printing ribbon in contact with both ends of the width of the printing ribbon. A tension adjusting mechanism having two spreading members that can move independently of each other and adjust the difference between the ribbon path length at the center of the width of the printing ribbon and the ribbon path length at both ends of the width, ,
A thermal printer comprising: The thermal printer according to claim 1.
The tension adjustment mechanism includes a pair of spreading members that can independently change a spreading amount on one side and a spreading amount on the other side of the width of the printing ribbon. The thermal printer according to claim 2,
Each spreading member of the tension adjustment mechanism
A ribbon contact side having a width corresponding to the ribbon width;
A center of rotation provided in a central part of the width and unevenly distributed from the ribbon contact side part;
A rotation amount setting unit for setting the rotation amount of the ribbon contact side around the rotation center;
A thermal printer characterized in that a rotation center portion of each expansion member is rotatably mounted around a rotation center provided at a center portion in the width direction of the ribbon feeding path. . The thermal printer according to claim 3.
The tension adjustment mechanism
A rotation scale provided on one side of the ribbon winding path;
In correspondence with the rotation amount scale, a mark portion provided at an end portion on one side when viewed from the rotation center portion of each spreading member,
And a rotation amount is set using a rotation amount scale and a mark portion of each spreader member.

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