JP2004174727A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer in which the slack of a print sheet can be eliminated accurately when it is back fed by imparting a tension constantly to the print sheet and the print sheet can be aligned exactly with a normal print position when it is carried again for printing. <P>SOLUTION: When a label sheet 12 is back fed, a first one-way clutch 32 slips with respect to a shaft 30 whereas a second one-way clutch 34 locks the shaft 30 and power is transmitted from a platen roller 16B to the shaft 30 which is thereby rotated. A tension is imparted to the label sheet 12 being back fed by a torque from a rotation controller 42 which rotates a boss member 40 together with the shaft 30. Since the boss member 40 rotates to wind the label sheet 12 while applying a tension thereto, the label sheet 12 can be prevented from slackening even when it is back fed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printer, and more particularly, to a printer that performs print transport and back feed transport of print paper.
[0002]
[Prior art]
As a printer that performs print transport and back feed transport of print paper, for example, after printing a belt-shaped print paper that has been printed and transported from the paper supply unit to the print unit by the print unit, a short paper, for example, for each sheet A printer provided with a cutting section for cutting into labels corresponds to this. In the case of this printer, when the printing paper printed by the printing unit is conveyed to the cutting unit, the printing position to be printed next is shifted to the cutting unit side from the regular printing position. It is necessary to carry back-feeding until the printing position is adjusted.
[0003]
However, the printing paper is slackened between the printing unit and the paper supply unit due to the back feed conveyance, and it is difficult to accurately convey the printing paper to the regular printing position when the printing is conveyed again, so that the printing misalignment easily occurs. In addition, the printing paper is likely to have a curl due to the looseness of the printing paper, and the so-called JAM phenomenon in which the printing paper is wrinkled or jammed in the printing portion due to the curl when the printing paper is conveyed again is likely to occur. . As a countermeasure, it is possible to arrange a motor in the sheet supply unit and forcibly rewind the sheet, but this increases the cost of the apparatus.
[0004]
As another countermeasure, Patent Document 1 discloses an example of a printer that performs only print conveyance and does not perform back-feed conveyance. However, by providing a roll paper shaft with a torque limiter in the printer, the roll paper shaft is rotated by inertia. It is disclosed to prevent the resulting roll paper from sagging.
[0005]
Patent Document 2 discloses an example of preventing the ink ribbon provided in the printer from being loosened. However, the tension at the time of pulling out the ink ribbon from the feed roller shaft of the ink ribbon causes the extension of the spring provided on the feed roller shaft. There is disclosed a rewinding means for accumulating an elastic repulsive force utilizing shrinkage and, when the tension is lost, sending out the ribbon and rewinding the roller by reversing the feeding roller shaft by the elasticity. .
[0006]
[Patent Document 1]
JP-A-2001-163495
[0007]
[Patent Document 2]
JP-A-5-193221 [0008]
[Problems to be solved by the invention]
However, the countermeasure described in Patent Document 1 is simply to prevent the printing paper from being loosened during printing conveyance, and cannot be directly applied to a printer that performs both printing conveyance and backfeed conveyance as in the present invention.
[0009]
Further, in the method using a spring disclosed in Patent Document 2, the size is limited due to the restriction on the space of the device, and it is difficult to make the elasticity due to the expansion and contraction of the spring uniform at all times. For this reason, there is a disadvantage that the slack of the printing paper due to the magnitude of the resilience cannot be eliminated with high accuracy, and the printing paper deviates from the regular printing position.
[0010]
The present invention has been made in view of such circumstances, and by always applying tension to the printing paper, the slack of the printing paper at the time of back feed conveyance can be eliminated with high accuracy, and when the print conveyance is performed again. It is an object of the present invention to provide a printer capable of accurately aligning with a regular printing position.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention conveys a paper supply unit mounted with a roll wound with a band-shaped print paper, a print head for printing on print paper supplied from the paper supply unit, and the print paper. A printing unit having a transport roller, the transport roller performs printing on the print paper while transporting the print paper in a forward direction, and rotates the transport roller in a reverse direction during the next printing. In a printer that performs print position alignment by back feeding and transporting the printing paper, the paper supply unit includes a shaft rotatably supported via a bearing on a frame of the paper supply unit, and the shaft. It is interposed between the boss member that supports the roll and generates torque during the print transport and the back feed transport, and generates the torque during the back feed transport. A rotation control device that is allowed to rotate in conjunction with the shaft, and is supported by the frame between the shaft and the frame, and locks the shaft during the print conveyance and the shaft during the back feed conveyance. A first one-way clutch that slips and is supported by the rotating pulley between the shaft and a rotating pulley that rotates in the same direction in synchronization with power transmission from the transport roller. And a second one-way clutch that locks the shaft during the back feed conveyance.
[0012]
According to the present invention, at the time of printing and transporting the printing paper, the first one-way clutch locks with respect to the shaft and the second one-way clutch slips with respect to the shaft, so that the power of the transport roller is transmitted to the shaft. Never. Therefore, the boss member on which the roll of printing paper is mounted rotates by the pulling force on the printing paper by the transport roller, and tension is applied to the printing paper that is printed and transported by the torque generated from the rotation control device. . Accordingly, the printing paper is fed out from the paper supply unit while being tensioned by the forward rotation of the transport roller and is transported for printing, so that the printing paper can be transported without being slackened.
[0013]
During the back feed conveyance of the printing paper, the first one-way clutch slips with respect to the shaft, and the second one-way clutch locks the shaft, so that the power of the conveyance roller is transmitted to the shaft and the shaft rotates. In addition, tension is applied to the printing paper that is back-fed by the torque from the rotation control device, and the rotation control device is allowed to rotate in conjunction with the shaft, so that the boss member rotates together with the rotation of the shast. I do. Thus, the boss member rotates to wind up the printing paper, and the rotation control device applies tension to the printing paper, so that the printing paper can be prevented from slackening even during back-feed conveyance.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the printer according to the present invention will be described in detail with reference to the accompanying drawings.
[0015]
FIG. 1 is a schematic diagram showing the entire configuration of a printer according to the present invention, which is necessary when a linerless label paper having a release agent layer on the front surface and an adhesive layer on the back surface is used as printing paper. An example of a label printer having a cutting unit will be described.
[0016]
As shown in FIG. 1, the label printer 5 mainly includes a label supply unit 10, a printing unit 16, and a cutting unit 18.
[0017]
The label supply unit 10 supports a roll 14 formed by winding a strip of label paper 12 having continuous label units in a roll shape. The label paper 12 is a platen roller of a printing unit 16 including a thermal head 16A and a platen roller 16B. It is pulled out by the rotation of 16B and fed out of the label supply unit 10. The platen roller 16B is rotated forward and backward by a stepping motor (not shown). By the normal rotation of the platen roller 16B, the label paper 12 fed from the label supply unit 10 is printed and conveyed to the printing unit 16 via the guide roller 20 and the optical detector 22. The optical detector 22 detects a detection mark (not shown) formed for each unit label (one label) of the label paper 12, and a control device (not shown) prints the label paper 12 based on the detection result. The print output information necessary for printing, such as the position and print content, is output to the printing unit 16. In the printing unit 16, characters, bar codes, and the like are printed at designated locations for each unit label. The label paper 12 printed by the printing unit 16 is conveyed by the platen roller 16B, sent to the cutting unit 18, and cut into unit labels.
[0018]
As described above, in the case of the label printer 5 having the cutting unit 18, when the label paper 12 printed by the printing unit 16 is conveyed to the cutting unit 18, the printing position to be printed next is shorter than the normal printing position. Therefore, the label position is adjusted by feeding the label paper 12 back-feed to a predetermined position of the printing unit 16. That is, when the platen roller 16B rotates forward, the label paper 12 is printed and transported, and when the platen roller 16B rotates reversely, the label paper 12 is transported back-feed. Accordingly, the label supply unit 10 has a structure described below so that the label paper 12 is not loosened between the label supply unit 10 and the printing unit 16 when the label paper 12 is back-fed and conveyed.
[0019]
FIG. 2 is a side cross-sectional view illustrating a schematic configuration of the label supply unit 10.
[0020]
As shown in FIG. 2, the label supply unit 10 mainly includes a rotary pulley 26, a shaft 30, a first one-way clutch 32, a second one-way clutch 34, a bearing 38, and a rotation control device 42.
[0021]
The shaft 30 is rotatably supported by a cantilever via a bearing 38 provided on the penetrated frame plate 7 while penetrating the frame plate 7 of the label supply unit 10.
[0022]
A rotation control device 42 is interposed between the shaft 30 and a boss member 40 that supports the roll 14 around which the label paper 12 is wound. Then, in order to mount the roll 14 on the label supply unit 10, the cylindrical core 14 A around which the roll 14 is wound is fitted into the convex boss 40 A of the boss member 40 from the open side of the shaft 30. Push it in until it contacts the guide 40B. Then, the holding plate 41 is inserted into the shaft 30, and the convex boss 41A formed on the holding plate 41 is fitted into the core portion 14A. As a result, the roll 14 is mounted on the label supply unit 10 and the boss member 40 and the pressing plate 41 rotate integrally with the roll 14.
[0023]
As shown in FIG. 3, the rotation control device 42 has a cylindrical case main body 50. The case main body 50 has an end wall 52 at one end and an opening 54 at the other end. It has a flange 56 (mounting portion) extending outward from the end wall 52. A shaft hole 51 through which the shaft 30 penetrates is formed at the center of the end wall 52, and a plurality of radially extending grooves 58 are formed in the end wall 52. In this case body 50, a sleeve 62 having a coil spring 60 fitted on its peripheral surface and a one-way clutch 64 mounted on the inner peripheral surface of the sleeve 62 are housed. The one-way clutch 64 is engaged with the sleeve 62 by fitting a groove 68 formed on the outer periphery of the one-way clutch 64 into a ridge 66 projecting from the inner peripheral surface of the sleeve 62. The coil spring 60 is positioned on the case main body 50 by inserting one end 70 into the groove 58 of the case main body 50. These are unitized by fitting a disc-shaped lid 72 having a shaft hole 74 formed in the opening 54 of the case body 50. The case body 50 and the coil spring 60 prohibit the rotation of the coil spring 60 around the sleeve 62 in the direction in which the winding of the coil spring 60 is tightened (diameter reduction). However, when a rotational force exceeding a predetermined value (torque value) is applied in the reverse direction, the coil spring 60 expands its diameter to allow rotation and generate torque. In the rotation control device 42 configured as described above, the flange 56 is fixed to the boss member 40 by a screw or the like, and the shaft hole 51 of the end wall 52 and the shaft hole 74 of the lid 72 are inserted into the shaft 30. The shaft 30 is set so as to be fitted to the inner peripheral surface of the one-way clutch 64. Accordingly, torque can be generated during printing and back-feeding, and rotation in conjunction with the shaft 30 is allowed during back-feeding.
[0024]
Further, a first one-way clutch 32 is interposed between the shaft 30 and the bearing base 36 supported by the frame plate 7. The first one-way clutch 32 is fixed to the bearing base 36 so that the first one-way clutch 32 is locked with respect to the shaft 30 at the time of printing and transporting the label paper 12 and slips with respect to the shaft 30 at the time of back feeding.
[0025]
A rotating pulley 26 is supported at one end of the shaft 30 opposite to the shaft 30 on which the roll 14 is mounted with the frame plate 7 interposed therebetween, and a second pulley 26 is provided between the shaft 30 and the rotating pulley 26. One-way clutch 34 is interposed while being fixed to rotary pulley 26. An endless timing belt 28 is stretched between the platen roller 16B and the rotary pulley 26, whereby the rotary pulley 26 rotates in the same direction in synchronization with the platen roller 16B. Then, the second one-way clutch 34 slips with respect to the shaft 30 during the printing conveyance, and locks the shaft 30 during the back feeding conveyance. Therefore, when printing and transporting the label paper 12, the power of the platen roller 16 </ b> B is not transmitted to the shaft 30, and the platen roller 16 </ b> B pulls the label paper 12 with a force larger than the predetermined torque value of the rotation control device 42, and The label paper 12 is fed out from the supply unit 10 and printed and conveyed.
[0026]
Next, the operation of the label supply unit 10 during the printing conveyance of the label paper 12 and the back feeding conveyance will be described with reference to the operation diagram of FIG. 4 and the table of FIG. Reference numerals 46 and 48 in FIG. 4 indicate the operation directions of the respective members shown in FIG. 5, wherein reference numeral 46 denotes printing conveyance and reference numeral 48 denotes back feed conveyance.
[0027]
When the platen roller 16B is rotated forward so that the label paper 12 is printed and conveyed, the second one-way clutch 34 slips with respect to the shaft 30, and the shaft 30 does not rotate in conjunction with the platen roller 16B. Is not transmitted to the boss member 40. Therefore, the boss member 40 is rotated by the pulling force of the label paper 12 due to the forward rotation of the platen roller 16B, and the label paper 12 of the label supply unit 10 is fed out from the label supply unit 10 and printed and conveyed. Due to the rotation of the boss member 40 caused by this feeding, the diameter of the coil spring 60 of the rotation control device 42 expands, and a torque for applying tension to the label paper 12 is generated. Thus, the label paper 12 fed from the label supply unit 10 is printed and conveyed without slack. However, in the slip state of the second one-way clutch 34, if a slight resistance is generated to transmit the rotation of the rotary pulley 26 to the shaft 30, the shaft 30 rotates and the slack of the label paper 12 is reduced. Become a factor. As a countermeasure, the first one-way clutch 32 fixed to the bearing base 36 is provided to lock the shaft 30, so that the shaft 30 is prevented from rotating together. Accordingly, the torque of the rotation control device 42 can be effectively and accurately exerted, and the label paper 12 can be printed and conveyed without being slackened.
[0028]
When the platen roller 16B is rotated in the reverse direction to feed the label paper 12 backward, the first one-way clutch 32 slips and the second one-way clutch 34 locks the shaft 30. It rotates in conjunction with. That is, the power of the platen roller 16B is transmitted to the shaft 30 via the timing belt 28, the rotary pulley 26, and the second one-way clutch 34, and the shaft 30 rotates in the direction of winding the label paper 12. As a result, the boss member 40 rotates in the direction of winding the label paper 12 via the rotation control device 42, and the coil spring 60 of the rotation control device 42 expands due to the rotation of the shaft 30. A torque for applying tension is generated. As a result, even during the back feed conveyance, the label paper 12 is wound around the boss member 40 in a state where the tension is applied, so that the label paper 12 can be prevented from loosening even during the back feed conveyance.
[0029]
As described above, in the label printer 5 of the present invention, by using the rotation control device 42 and the first and second one-way clutches 32 and 34, the tension is always applied to the label paper in both the print conveyance and the back feed conveyance. 12 can be given. Thus, the label paper 12 can be transported without slack, and the slack of the label paper 12 can be eliminated with high accuracy, so that it is possible to accurately align the label paper 12 with the regular printing position. Further, the label paper 12 is fed out from the label supply unit 10 to change the diameter of the roll 14 to change the load, and the label paper 12 caused by excessive feeding of the label paper 12 due to inertia when the roll 14 rotates. Can be reliably prevented, and the printing position can always be maintained at an accurate position.
[0030]
In addition, the label printer 5 is not limited to a printer having the cutting unit 18, but is provided with a peeling device necessary when label paper with a mount temporarily attached to a band-shaped mount at a fixed interval is used as printing paper. It can also be applied to label printers.
[0031]
Further, in the present embodiment, an example of a thermal printer in which the printing unit 16 includes the thermal head 16A and the platen roller 16B has been described. However, the present invention is not limited to this. The present invention can be applied to all printers having a paper supply unit in which a roll having a winding direction (front winding) is mounted.
[0032]
【The invention's effect】
As described above, according to the present invention, the slack of the printing paper at the time of back feed conveyance can be eliminated with high accuracy, and the printing can be accurately aligned with the regular printing position when the printing paper is fed again.
[0033]
In addition, the present invention reduces the load variation in the paper supply unit and reduces the amount of deviation in paper feeding to the printing unit as compared with the conventional technology. And problems such as JAM can be reduced.
[0034]
Further, in the printer of the present invention, when using printing paper with a backing sheet that requires peeling, it is possible to improve the peeling position accuracy, and when using linerless printing paper that requires cutting, cutting is performed. Position accuracy can be improved.
[0035]
Further, by using the same power source as the transport roller for the power of the paper supply unit in both the print transport and the back-feed transport, it is possible to simplify the apparatus and reduce the apparatus cost, thereby reducing the running cost. Reduction and space saving of the device can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of a label printer with a cutter device. FIG. 2 is an explanatory diagram illustrating the structure of a label supply unit. FIG. 3 is an exploded view illustrating the structure of a rotation control device. FIG. 5 is an explanatory diagram for explaining the operation of the supply unit. FIG. 5 is a table for explaining the operation of each member of the label supply unit.
5: Label printer with cutting unit, 7: Frame plate of label supply unit (frame plate of paper supply unit), 10: Label supply unit (paper supply unit), 12: Label paper (print paper), 14: Roll, Reference numeral 16: printing section, 16A: thermal head (printing head), 16B: platen roller (conveying roller), 18: cutting section, 20: guide roller, 22: optical detector, 26: rotary pulley, 28: timing belt, 30 ... shaft, 32 ... first one-way clutch, 34 ... second one-way clutch, 36 ... bearing base, 38 ... bearing (bearing), 40 ... boss member, 40A ... boss, 40B ... roll guide, 41 ... holding plate, 41A: boss of the holding plate, 42: rotation control device, 46: operating direction of each member of the label supply unit during printing conveyance, 48: each member of the label supply unit Operating direction during back feed conveyance, 50: case body, 52: end wall, 54: opening, 56: flange, 58: groove, 60: coil spring, 62: sleeve, 64: one-way clutch, 66: ridge, 68 Groove, 70 ... One end, 72 ... Lid, 74 ... Hole

Claims (1)

It has a paper supply unit for mounting a roll wound with a belt-shaped print paper, and a print unit having a print head for printing on the print paper supplied from the paper supply unit and a transport roller for transporting the print paper. By carrying out printing on the printing paper while the feeding roller is rotating forward and printing and feeding the printing paper, the feeding roller is rotated in the reverse direction at the next printing to feed the printing paper in a back feed manner. In a printer that performs print position alignment,
The paper supply unit includes:
A shaft rotatably supported by a frame of the paper supply unit via a bearing,
A rotation control device that is interposed between the shaft and a boss member that supports the roll, generates a torque during the print conveyance and the backfeed conveyance, and allows rotation interlocked with the shaft during the backfeed conveyance. When,
A first one-way clutch that is supported by the frame between the shaft and the frame, locks the shaft during the print conveyance, and slips with respect to the shaft during the back feed conveyance;
The rotary pulley is supported between the shaft and a rotary pulley that rotates in the same direction in synchronization with power transmission from the transport roller. A second one-way clutch for locking the shaft;
A printer comprising:

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