JP2008049670A - Label printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a label printer which can make the tension to be fixed in a print medium which is fed out from a paper supply spindle without the sway of a rolled paper loaded into a paper supply spindle also when the rolled paper having a larger internal diameter than that of the paper supply spindle is used. <P>SOLUTION: The label printer comprises a paper supply spindle 31 which loads a rolled paper 7 in the condition that a print medium 4 is wound around a cylindrical body 6 and has a smaller internal diameter than that of a cylindrical body 6, a roller with passive rotation 33 which is arranged movably up and down under the paper supply spindle 31, is biased downward, and contacts to the inner circumference surface of the rolled paper 7 loaded in the paper supply spindle 31, a paper supply shaft drive motor carries out the rotary drive of the paper supply spindle 31 linking with the conveying of the print medium 4 by the platen roller 11 and thereby feeds out the print medium 4 from the paper supply spindle 31, and an adding tension means 17 which gives fixed tension to the print medium 4 which is fed out to a printing part from the paper supply spindle 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a label printer having a paper supply shaft for mounting a roll paper in which a print-receiving medium such as a label continuous body is wound around a cylindrical body such as a paper tube. The present invention relates to a label printer that rotates and feeds out a printing medium.

  A roll of paper to be printed, such as a label continuum on which a plurality of labels are temporarily attached to a belt mount, is wound around a cylindrical body such as a paper tube. In a conventional label printer that feeds a print medium and prints it, if the print medium fed from the paper supply shaft to the print section becomes slack, the label may be peeled off from the belt or the print position may be misaligned. There was a risk of getting lost.

  Therefore, a slack detection sensor that detects slack of the printing medium fed from the paper supply shaft to the printing unit is provided, and the rotation shaft is rotated based on the detection information of the slack detection sensor to remove slack of the printing medium. Has been proposed (see, for example, Patent Document 1).

  However, in the prior art, it is assumed that a roll paper having an inner diameter substantially the same as the paper supply shaft is used as the roll paper mounted on the paper supply shaft. Not intended for use. If roll paper with an inner diameter larger than the paper supply shaft is used, the roll paper loaded on the paper supply shaft will shake, and the tension of the print medium fed from the paper supply shaft to the printing unit will become unstable. There is a problem that the label is peeled off from the belt-like mount or the printing position is shifted.

JP 2000-301785 A

  The present invention has been made in view of such problems, and the object of the present invention is to provide a roll paper mounted on a paper supply shaft even when a roll paper having an inner diameter larger than that of the paper supply shaft is used. Provided is a label printer that can maintain a constant tension of a print medium fed from a paper supply shaft to a printing unit without shaking, and can prevent a label from being peeled off from a belt-like mount and a print position deviation. In the point.

In order to solve the above problems, the present invention has the following configuration.
The gist of the invention described in claim 1 is a label printer that performs printing while conveying a printing medium by printing means, and is loaded with a roll paper in a state where the printing medium is wound around a cylindrical body. A paper supply shaft having a diameter smaller than the inner diameter of the cylindrical body, a paper supply shaft disposed below the paper supply shaft so as to be vertically movable, and urged downward to be mounted on the paper supply shaft. The print medium is fed out from the paper supply shaft by rotating the paper supply shaft in conjunction with a driven roller that contacts the inner peripheral surface of the roll paper and the conveyance of the print medium by the printing means. The present invention resides in a label printer comprising: a rotation driving unit; and a tension applying unit that applies a certain tension to the print medium fed from the paper supply shaft to the printing unit.
According to a second aspect of the present invention, there is provided a displacement detecting means for detecting a displacement of the tension applying means according to a length of the printing medium fed from the paper supply shaft to the printing means, and the displacement detecting means. 2. The label printer according to claim 1, further comprising a rotation control unit that controls a rotation speed of the paper supply shaft by the rotation driving unit in accordance with the displacement of the tension applying unit detected by the step.
According to a third aspect of the present invention, the rotation control unit is fed out from the paper supply shaft when the rotation driving unit conveys the print medium in a direction to be wound around the paper supply shaft. When the printing medium is shorter than a predetermined value, the rotation speed of the paper supply shaft is slow, and when the printing medium fed from the paper supply shaft is longer than a predetermined value Is controlled so as to increase the rotational speed of the paper supply shaft, and when the print medium is transported in the direction of feeding out from the paper supply shaft by the rotation driving means, the paper supply shaft is fed out from the paper supply shaft. When the print medium to be printed is shorter than a predetermined value, the rotation speed of the paper supply shaft is increased, and the print medium fed from the paper supply shaft is longer than the predetermined value. The consists in a label printer according to claim 2, wherein the controller controls so as to slow the rotation speed of the paper feed shaft.

  The label printer according to the present invention includes a paper supply shaft having a diameter smaller than the inner diameter of the cylindrical body and a lower side of the paper supply shaft. In conjunction with the conveyance of the printing medium by the printing means, and a driven roller that is movably disposed and is urged downward and contacts the inner peripheral surface of the roll paper mounted on the paper supply shaft, By providing rotation driving means for feeding out the print medium from the paper supply shaft by rotating the paper supply shaft and tension applying means for applying a certain tension to the print medium fed from the paper supply shaft to the printing means. Even when roll paper having an inner diameter larger than that of the paper supply shaft is used, the roll paper is stably and rotatably held by the paper supply shaft and the driven roller. Do not shake Further, since the printing medium fed from the paper supply shaft to the printing unit by the rotation driving unit is given a constant tension by the tension applying unit, the tension of the printing medium fed from the paper supply shaft to the printing unit is constant. And the effect of preventing the peeling of the label from the belt-like mount and the displacement of the printing position can be achieved.

  Further, the label printer of the present invention includes a displacement detecting means for detecting a displacement of the tension applying means according to the length of the printing medium fed from the paper supply shaft to the printing means, and a tension applying detected by the displacement detecting means. Rotation control means for controlling the rotation speed of the paper supply shaft by the rotation drive means according to the displacement of the means is provided, and when the medium to be printed is conveyed in the direction of winding around the paper supply shaft, the rotation control means When the printing medium fed out from the supply shaft becomes shorter than the predetermined value, the rotation speed of the paper feeding shaft is slow, and the printing medium fed out from the paper supply shaft becomes longer than the predetermined value. In this case, control is performed to increase the rotation speed of the paper supply shaft, and when the medium to be printed is transported in the direction of feeding out from the paper supply shaft, the paper is supplied by the rotation control means. When the printing medium fed out from the paper supply becomes shorter than the predetermined value, the rotation speed of the paper supply shaft is increased, and the printing medium fed out from the paper supply shaft becomes longer than the predetermined value. By controlling the rotation speed of the paper supply shaft to be slow, the length of the printing medium fed from the paper supply shaft to the printing means can be controlled within a predetermined range, and printing can be performed from the paper supply shaft. The printing medium can be stably supplied to the means.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the embodiment of the label printer according to the present invention, and FIG. 2 is a schematic perspective view showing the configuration of the embodiment of the label printer according to the present invention. These are the block diagrams which show the internal structure of embodiment of the label printer which concerns on this invention.

  1 and 2, the label printer 1 of the present embodiment includes a platen roller 11 and a thermal head 12 having a heating element formed on a surface facing the platen roller 11 as a printing unit. A printing medium 4 such as a label continuous body in which a plurality of labels 2 are temporarily attached to a belt-like mount 3 and an ink ribbon 5 are overlapped and sandwiched between a platen roller 11 and a thermal head 12, and the thermal head 12 By selectively heating the heating element, the ink is transferred from the ink ribbon 5 onto the printing surface of the printing medium 4 (label 2) to print desired characters, barcodes, and the like. .

  The print medium 4 is wound around a cylindrical body 6 such as a paper tube in a roll shape, that is, is rotatably supported by the supply unit 13 as roll paper 7, and the platen roller 11 and the thermal head 12 are supplied from the supply unit 13. Supplied between. The ink ribbon 5 is stretched between the ribbon paper supply shaft 14 and the ribbon take-up shaft 15, and the ink ribbon 5 supported in a state of being wound around the ribbon paper supply shaft 14 in a roll shape is The ink ribbon 5 that is supplied together with the printing medium 4 between the roller 11 and the thermal head 12 and is transferred is taken up by the ribbon take-up shaft 15.

  The supply unit 13 is rotationally driven in accordance with the printing operation, and is disposed below the paper supply shaft 31 having a diameter smaller than the inner diameter of the cylindrical body 6 of the roll paper 7 to be mounted, and below the paper supply shaft 31. It is comprised with the driven roller 33 comprised so that it could move up and down along the slit 32 formed in the direction. The driven roller 33 is urged in a downward direction away from the paper supply shaft 31 as indicated by an arrow in FIG. 1, and the paper supply shaft 31 and the driven roller 33 abut against the inner peripheral surface of the cylindrical body 6. The roll paper 7 is attached so as to be in contact with the roll body 7, and the roll paper 7 having a different inner diameter of the cylindrical body 6 can be attached. 2, the strength of the paper supply shaft 31 is reinforced by a frame 34 attached to the side of the main body, and the weight of the printing medium 4 wound around the cylindrical body 6 in a roll shape and It is configured to withstand the urging force of the driven roller 33.

  In the conveyance path from the supply unit 13 to the printing unit, there are a pair of guide rollers 16 and a tension applying unit 17 that abuts against the printing medium 4 spanned between the pair of guide rollers 16 and applies a certain tension. Is provided.

  The tension applying means 17 includes a tension arm 71, a rotation shaft 72 that rotatably supports one end of the tension arm 71, a contact roller 73 that is rotatably provided at the free end of the tension arm 71, and a tension arm. A spring 74 that functions as an urging means that urges 71 in the direction indicated by the arrow in FIG. A rotation detection sensor 75 is provided on the shaft 72 and detects the rotation of the tension arm 71.

  Since the tension arm 71 is urged downward by the spring 74 so that the contact roller 73 presses the print medium 4, the print medium 4 fed out to the conveyance path from the supply unit 13 to the print unit is long. Then, the contact roller 73 rotates clockwise by moving downward, and when the printing medium 4 fed out to the conveyance path from the supply unit 13 to the printing unit becomes shorter, the contact roller 73 moves upward. It moves counterclockwise by moving to. Therefore, by detecting the rotation of the tension arm 71 by the rotation detection sensor 75, it is possible to detect a change in the feeding amount of the printing medium 4 in the conveyance path from the supply unit 13 to the printing unit. As the rotation detection sensor 75, an optical sensor that optically detects a volume whose resistance value changes as the rotation shaft 72 rotates and a plurality of slits formed in a disk that rotates together with the rotation shaft 72. A pair of switches that are pressed when the tension arm 71 is rotated to a predetermined position can be used.

  Referring to FIG. 3, the rotation position of the tension arm 71 detected by the rotation detection sensor 75 is configured to be determined by the rotation position determination unit 18, and the thermal head 12 includes the print control unit 19. The platen drive motor 20 that rotationally drives the platen roller 11 and the paper supply shaft drive motor 21 that rotationally drives the paper supply shaft 31 are controlled by the rotation control unit 22. Further, an input unit 23 for receiving print data to be printed on the print medium 4 and a print start instruction for instructing the start of printing is provided.

  The rotation position determination unit 18 determines the rotation speed of the paper supply shaft 31 by determining the rotation position of the tension arm 71 detected by the rotation detection sensor 75, and the rotation control unit 22 determines the determined rotation speed. Output to.

  When a print start instruction is input to the input unit 23, the print control unit 19 outputs to the rotation control unit 22 a drive start signal that instructs to start driving the platen drive motor 20 and the paper supply shaft drive motor 21. Based on the print data input from the unit 23, the heat generating body of the thermal head 12 is selectively heated to transfer the ink from the ink ribbon 5 to the print surface of the print medium 4 (label 2), thereby forming a desired character. , Barcodes, etc. are printed.

  The rotation control unit 22 includes a driver circuit that drives the platen drive motor 20 and the paper supply shaft drive motor 21, and when a drive start signal is input from the print control unit 19, the platen drive motor 20 and the paper supply shaft drive. The motor 21 is rotated in the reverse direction so that the print medium 4 is wound in the reverse direction, that is, the print medium 4 is wound around the paper supply shaft 31 until the leading end of the label 2 on which printing is not performed is opposed to the thermal head 12. The print medium 4 is conveyed until the platen drive motor 20 and the paper supply shaft drive motor 21 are rotated forward and the rear end of the printed label 2 is discharged from the discharge port 24. Are conveyed in the forward direction, that is, in the direction in which the print medium 4 is fed out from the paper supply shaft 31. FIG. 1 shows a state in which the rear end of the printed label 2 is discharged from the discharge port 24.

Next, the printing operation of the present embodiment will be described in detail with reference to FIG. 4 and FIG.
FIG. 4 is a flowchart for explaining the operation of transporting the medium to be printed accompanying printing in the embodiment of the label printer according to the present invention. FIG. 5 shows the determination operation of the rotational position determination unit shown in FIG. It is explanatory drawing for demonstrating.

  The rotation control unit 22 monitors the input of the drive start signal from the print control unit 19 (step A1), and when the drive start signal is input from the print control unit 19, the platen drive motor 20 and the paper supply shaft drive. The motor 21 is rotated in the reverse direction (step A2), and the print medium 4 is conveyed (back fed) in the reverse direction, that is, in the direction in which the print medium 4 is wound around the paper supply shaft 31.

  In the rotation position determination unit 18, the rotation position of the tension arm 71 detected by the rotation detection sensor 75 is set in advance to a preset upper position α as shown in FIG. It is determined whether or not it is positioned between the lower position β (step A3), and if the tension arm 71 is positioned between the upper position α and the lower position β, the rotation of the paper supply shaft 31 is determined. The speed is determined to be a preset rotation speed A ′ (step A4), and the determined rotation speed A ′ is output to the rotation control unit 22. The rotation control unit 22 moves the paper supply shaft 31 at the rotation speed A ′. The paper supply shaft drive motor 21 is controlled to rotate in the reverse direction. The rotation speed A ′ is set so that the conveyance speed of the printing medium 4 wound up by the reverse rotation of the paper supply shaft 31 is substantially the same as the conveyance speed of the printing medium 4 by the platen roller 11. . Actually, even if the paper supply shaft 31 is rotated at the same speed, the conveyance speed of the print medium 4 depends on the diameter of the roll paper 7, that is, the diameter of the print medium wound around the cylindrical body 6. Changes. Accordingly, when the paper supply shaft 31 is rotated in the reverse direction at the rotational speed A ′, the transport speed of the print medium 4 that is wound when the roll paper 7 has the largest diameter is greater than the transport speed of the print medium 4 by the platen roller 11. It is set so that the conveyance speed of the printing medium 4 that is rolled up when the roll paper 7 is the smallest diameter is slower than the conveyance speed of the printing medium 4 by the platen roller 11.

  When the rotation position of the tension arm 71 is not located between the upper position α and the lower position β in step A3, the rotation position determination unit 18 detects the tension detected by the rotation detection sensor 75. As shown in FIG. 5B, it is determined whether or not the pivot position of the arm 71 is positioned above the upper position α (step A5).

  In step A5, when the rotational position of the tension arm 71 is positioned above the upper position α, that is, when the printing medium 4 fed from the paper supply shaft 31 becomes shorter than a predetermined value, the rotation is performed. The moving position determination unit 18 determines the rotation speed of the paper supply shaft 31 to be a rotation speed B ′ that is slower than the rotation speed A ′ (step A6), and outputs the determined rotation speed B ′ to the rotation control unit 22 for rotation. The control unit 22 controls the paper supply shaft drive motor 21 so as to reversely rotate the paper supply shaft 31 at the rotation speed B ′. Note that the rotation speed B ′ is such that when the paper supply shaft 31 is reversely rotated at the rotation speed B ′, the conveyance speed of the print medium 4 that is wound when the roll paper 7 has the largest diameter is determined by the platen roller 11. It is set to be slower than the conveyance speed of the medium 4.

  In step A5, when the rotational position of the tension arm 71 is not located above the upper position α and is located below the lower position β, that is, the printing target fed out from the paper supply shaft 31. When the medium 4 becomes longer than the predetermined value, the rotation position determination unit 18 determines the rotation speed C ′ of the sheet supply shaft 31 to be higher than the rotation speed A ′ (Step A7). ), The determined rotation speed C ′ is output to the rotation control unit 22, and the rotation control unit 22 controls the sheet supply shaft drive motor 21 to reversely rotate the sheet supply shaft 31 at the rotation speed C ′. Note that the rotation speed C ′ is such that when the paper supply shaft 31 is rotated in reverse at the rotation speed C ′, the conveyance speed of the print medium 4 that is wound when the roll paper 7 is the smallest diameter is the print medium by the platen roller 11. 4 is set to be faster than the conveyance speed of 4.

  Next, the rotation control unit 22 determines whether or not the leading end of the label 2 that has not been printed has reached the printing position (position facing the thermal head 12) (step A8), and reaches the printing position. Steps A3 to A7 are repeated. The position of the tip of the label 2 is determined by, for example, forming an eye mark (black rectangular mark) on the back side of the print medium 4 by printing or the like, and detecting the eye mark by a paper detection sensor (not shown). Can be recognized. Further, the sheet pitch may be detected by detecting a gap between labels or a label leading edge instead of the eye mark.

  When the print position is reached in step A8, the rotation control unit 22 rotates the platen drive motor 20 and the paper supply shaft drive motor 21 in the forward direction (step A9), and the print medium 4 is moved in the forward direction, that is, the print medium. 4 is conveyed in the direction of feeding out from the paper supply shaft 31, and the print control unit 19 selectively heats the heating element of the thermal head 12 based on the print data input from the input unit 23, whereby the print medium 4 Ink is transferred from the ink ribbon 5 onto the printing surface of (Label 2) to print desired characters, barcodes, and the like.

  In the rotation position determination unit 18, the rotation position of the tension arm 71 detected by the rotation detection sensor 75 is set in advance to a preset upper position α as shown in FIG. It is determined whether or not it is positioned between the lower position β (step A10), and if the tension arm 71 is positioned between the upper position α and the lower position β, the rotation of the sheet supply shaft 31 is determined. The speed is determined as a preset rotation speed A (step A11), and the determined rotation speed A is output to the rotation control unit 22. The rotation control unit 22 causes the paper supply shaft 31 to rotate forward at the rotation speed A. In this way, the paper supply shaft drive motor 21 is controlled. The rotation speed A is set so that the conveyance speed of the printing medium 4 fed out by the normal rotation of the paper supply shaft 31 is substantially the same as the conveyance speed of the printing medium 4 by the platen roller 11. Actually, even if the paper supply shaft 31 is rotated at the same speed, the conveyance speed of the print medium 4 depends on the diameter of the roll paper 7, that is, the diameter of the print medium wound around the cylindrical body 6. Changes. Therefore, when the paper supply shaft 31 is rotated forward at the rotational speed A, the transport speed of the print medium 4 that is fed out when the roll paper 7 is the largest diameter is faster than the transport speed of the print medium 4 by the platen roller 11. The conveyance speed of the printing medium 4 fed out when the roll paper 7 is the smallest diameter is set to be slower than the conveyance speed of the printing medium 4 by the platen roller 11.

  If the rotation position of the tension arm 71 is not located between the upper position α and the lower position β in step A10, the rotation position determination unit 18 detects the tension detected by the rotation detection sensor 75. As shown in FIG. 5B, it is determined whether or not the pivot position of the arm 71 is positioned above the upper position α (step A12).

  In step A12, when the rotational position of the tension arm 71 is located above the upper position α, that is, when the print medium 4 fed from the paper supply shaft 31 is shorter than a predetermined value, The rotation position determination unit 18 determines the rotation speed B of the paper supply shaft 31 to be higher than the rotation speed A (Step A13), and outputs the determined rotation speed B to the rotation control unit 22 for rotation. The control unit 22 controls the paper supply shaft drive motor 21 so that the paper supply shaft 31 is rotated forward at the rotation speed B. The rotational speed B is such that when the paper supply shaft 31 is rotated forward at the rotational speed B, the transport speed of the print medium 4 fed out when the roll paper 7 is the smallest diameter is the transport speed of the print medium 4 by the platen roller 11. It is set to be faster than the speed.

  In step A12, when the rotational position of the tension arm 71 is not located above the upper position α and is located below the lower position β, that is, the printing target fed out from the paper supply shaft 31. When the medium 4 becomes longer than the predetermined value, the rotation position determination unit 18 determines the rotation speed C of the sheet supply shaft 31 as the rotation speed C slower than the rotation speed A (Step A14). The speed C is output to the rotation control unit 22, and the rotation control unit 22 controls the paper supply shaft drive motor 21 so that the paper supply shaft 31 rotates forward at the rotational speed C. The rotation speed C is such that when the paper supply shaft 31 is rotated forward at the rotation speed C, the conveyance speed of the print medium 4 that is fed out when the roll paper 7 is the largest diameter is the same as that of the print medium 4 by the platen roller 11. It is set to be slower than the conveyance speed.

  Next, the rotation control unit 22 determines whether or not the rear end of the printed label 2 has reached the discharge position discharged from the discharge port 24 (step A15), and until the discharge position is reached, When the operations of Step A10 to Step A14 are repeated and the discharge position is reached, the transport operation of the printing medium 4 is stopped. The position of the rear end of the label 2 is determined by, for example, forming an eye mark (black rectangular mark) on the back side of the print medium 4 by printing or the like, and detecting the eye mark by a paper detection sensor (not shown). Can be recognized by. Further, the sheet pitch may be detected by detecting a gap between labels or a label leading edge instead of the eye mark.

  As described above, according to the present embodiment, a paper supply having a diameter smaller than the inner diameter of the cylindrical body 6 on which the roll paper 7 with the print medium 4 wound around the cylindrical body 6 is mounted. A shaft 31 and a driven roller that is disposed below the paper supply shaft 31 so as to be movable in the vertical direction and is urged downward to contact the inner peripheral surface of the roll paper 7 mounted on the paper supply shaft 31. 33, a paper supply shaft drive motor 21 that feeds the print medium 4 from the paper supply shaft 31 by rotating the paper supply shaft 31 in conjunction with the conveyance of the print medium 4 by the platen roller 11, and a paper supply shaft. A roll paper 7 having an inner diameter larger than that of the paper supply shaft 31 is provided by providing tension applying means 17 for applying a constant tension to the print medium 4 fed from 31 to the printing unit (platen roller 11 and thermal head 12). Using Even in this case, since the roll paper 7 is stably and rotatably held by the paper supply shaft 31 and the driven roller 33, the roll paper 7 mounted on the paper supply shaft 31 does not shake, and further, the paper supply shaft Since the printing medium 4 fed from 31 to the printing unit is given a constant tension by the tension applying means 17, the tension of the printing medium 4 fed from the paper supply shaft 31 to the printing unit can be made constant. Thus, there is an effect that it is possible to prevent peeling of the label 2 from the belt-shaped mount 3 and displacement of the printing position.

  Furthermore, according to the present embodiment, the rotation detection sensor 75 that detects the displacement of the tension applying unit 17 according to the length of the print medium 4 fed from the paper supply shaft 31 to the printing unit, and the rotation detection. A rotation control unit 22 for controlling the rotation speed of the paper supply shaft 31 by the paper supply shaft drive motor 21 according to the displacement of the tension applying means 17 detected by the sensor 75 is provided, and the print medium 4 is attached to the paper supply shaft 31. When transporting in the winding direction, if the printing medium 4 fed from the paper supply shaft 31 becomes shorter than a predetermined value by the rotation control unit 22, the rotational speed of the paper supply shaft 31 is decreased. When the printing medium 4 fed out from the paper supply shaft 31 becomes longer than a predetermined value, control is performed to increase the rotation speed of the paper supply shaft 31 and the printing medium 4 is supplied to the paper supply shaft 31. When transporting in the feeding direction from the shaft 31, if the print medium 4 fed from the paper supply shaft 31 becomes shorter than a predetermined value by the rotation control unit 22, the rotation speed of the paper supply shaft 31 is reached. When the print medium 4 fed out from the paper supply shaft 31 becomes longer than a predetermined value, the rotation speed of the paper supply shaft 31 is controlled so as to be slowed down. The length of the print medium 4 fed to the print unit can be controlled within a predetermined range, and the print medium 4 can be stably supplied from the paper supply shaft 31 to the print unit.

  Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention. In each figure, the same numerals are given to the same component.

It is a block diagram which shows the structure of embodiment of the label printer which concerns on this invention. 1 is a schematic perspective view showing the configuration of an embodiment of a label printer according to the present invention. It is a block diagram which shows the internal structure of embodiment of the label printer which concerns on this invention. It is a flowchart for demonstrating the conveyance operation of the to-be-printed medium accompanying printing in embodiment of the label printer which concerns on this invention. It is explanatory drawing for demonstrating the determination operation | movement of the rotation position determination part shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Label printer 2 Label 3 Band mount 4 Printed medium 5 Ink ribbon 6 Cylindrical body 7 Roll paper 11 Platen roller 12 Thermal head 13 Supply part 14 Ribbon paper supply shaft 15 Ribbon take-up shaft 16 Guide roller 17 Tension provision means 18 times Movement position determination unit 19 Print control unit 20 Platen drive motor 21 Paper supply shaft drive motor 22 Rotation control unit 23 Input unit 24 Discharge port 31 Paper supply shaft 32 Slit 33 Followed roller 34 Frame body 71 Tension arm 72 Rotating shaft 73 Contact Roller 74 Spring 75 Rotation detection sensor (displacement detection means)

Claims (3)

A label printer that performs printing while conveying a medium to be printed by printing means,
A paper supply shaft having a diameter smaller than the inner diameter of the cylindrical body, to which a roll paper in a state where the printing medium is wound around the cylindrical body is mounted;
A driven roller disposed below the paper supply shaft so as to be movable in the vertical direction and biased downward, and abutting against an inner peripheral surface of the roll paper mounted on the paper supply shaft;
Rotation drive means for feeding out the print medium from the paper supply shaft by rotating the paper supply shaft in conjunction with conveyance of the print medium by the printing means;
A label printer comprising: a tension applying unit that applies a certain tension to the printing medium fed from the paper supply shaft to the printing unit. A displacement detecting means for detecting a displacement of the tension applying means according to a length of the printing medium fed from the paper supply shaft to the printing means;
2. The label according to claim 1, further comprising a rotation control unit that controls a rotation speed of the paper supply shaft by the rotation driving unit according to the displacement of the tension applying unit detected by the displacement detection unit. Printer.   When the rotation control means transports the print medium in the direction of winding around the paper supply shaft by the rotation driving means, the print medium fed from the paper supply shaft is shorter than a predetermined value. In this case, the rotation speed of the paper supply shaft is decreased, and when the print medium fed from the paper supply shaft becomes longer than a predetermined value, the rotation speed of the paper supply shaft is increased. When the print medium is conveyed in the direction of being fed out from the paper supply shaft by the rotation driving means, the print medium fed out from the paper supply shaft is shorter than a predetermined value. The rotation speed of the paper supply shaft is increased, and the rotation speed of the paper supply shaft is increased when the printing medium fed from the paper supply shaft becomes longer than a predetermined value. Claim 2, wherein the label printer and controls to slow.

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