JP2006272610A - Printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing device which can effectively prevent curling of a printing paper from occurring. <P>SOLUTION: In this label printer 1, when a specified period of time has passed from a point of the latest printing completion, a platen roller 33 is driven, and a label paper LP is carried in two direction of the normal carrying direction and the reverse carrying direction by the same carrying distance. Thus, the label paper LP is slightly let out from a label roll on a label holding shaft 31. As a result, the tension of the label paper LP which is applied to a guide roller 32 is softened, and therefore, the curling in the label paper LP resulting from the contact with the guide roller 32 can effectively be prevented from occurring. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing apparatus for printing on a long print sheet.

  In a printing apparatus such as a receipt printer that prints a receipt or a label printer that prints a label, a long print sheet is a printing target. Such a long printing paper is held by a rotatable holding shaft while being wound in a roll shape inside the printing apparatus, and one end thereof can be fed out. The printing paper is conveyed from the holding shaft to the position where printing is performed by the printing head while being guided by the guide roller (see, for example, Patent Document 1).

JP 2004-189304 A

  By the way, the guide roller defines a part of the conveyance path of the printing paper, but the portion of the printing paper that comes into contact with the guide roller is deformed into a substantially circular shape along the outer peripheral shape of the guide roller. During the printing operation, the printing paper is sequentially conveyed and the corresponding portions of the printing paper are also sequentially replaced, so that no particular problem occurs.

  However, since the conveyance of the printing paper is stopped after the printing is completed, the deformed state is maintained for the portion of the printing paper that is in contact with the guide roller. For this reason, if left as it is, curling (so-called “wrinkle”) may occur in the portion of the printing paper.

  Such curling causes a decrease in print quality, such as “position displacement” and “blurring” of print contents in subsequent printing. In particular, in a printing apparatus having a printing paper cutting mechanism such as a label cutter, a cutting failure or a paper jam may occur due to curling.

  SUMMARY An advantage of some aspects of the invention is that it provides a printing apparatus that can effectively prevent curling of printing paper.

  In order to solve the above-mentioned problem, the invention of claim 1 is a printing apparatus for printing a long print sheet, a holding unit that holds the unprinted print sheet in a roll state, and the holding unit A print head for printing on the printing paper present at a predetermined printing position conveyed from the printer, and a part of a conveyance path of the printing paper from the holding means to the printing position in contact with the printing paper A path defining member; and a tension relaxing unit that unwinds the printing paper from the holding unit and relaxes the tension of the printing paper applied to the path defining member when the print head is not printing.

  According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the tension relaxation means is a conveying means for conveying the printing paper from the holding means to the printing position.

  The invention according to claim 3 is the printing apparatus according to claim 2, wherein the tension relaxation means transports the printing paper for a predetermined distance in a first direction in which the printing paper is fed out from the holding means. The tension of the printing paper is relieved by transporting the printing paper in the second direction opposite to the first direction by the same distance as the predetermined distance.

  According to a fourth aspect of the present invention, in the printing apparatus according to any one of the first to third aspects, the tension relaxation means relaxes the tension of the printing paper after a predetermined time has elapsed since the operation of the print head stopped. To do.

  According to a fifth aspect of the present invention, in the printing apparatus according to any one of the first to fourth aspects, the printed printing paper is disposed near an issuing port through which the printed printing paper is issued. Cutting means for cutting.

  According to the first to fifth aspects of the present invention, it is possible to effectively prevent the curling of the printing paper caused by the contact with the path defining member. As a result, it is possible to prevent a decrease in print quality due to curling.

  In particular, according to the invention of claim 2, since the tension relaxation means and the transport means are used together, no special mechanism is required for preventing the occurrence of curling.

  In particular, according to the invention of claim 3, since the transport distance of the printing paper in both the first direction and the second direction for relaxing the tension is the same, it exists at the printing position before the tension relaxing operation. The portion of the printing paper that has been present exists in the printing position even after the tension relaxation operation, and the print content does not deviate from the original position by the tension relaxation operation.

  In particular, according to the invention of claim 4, it is possible to automatically perform the operation of relaxing the tension without any user operation.

  Further, in particular, according to the invention of claim 5, since the curling of the printing paper can be effectively prevented, even when the printing paper is cut, the printing paper is jammed at the issuing port or the cutting failure is caused. It does not occur.

  Hereinafter, a label printer that prints a label will be described with reference to the drawings as an example of a printing apparatus according to an embodiment of the present invention.

<1. Configuration>
FIG. 1 is a perspective view of the label printer 1. The label printer 1 has a function of printing a label and issuing a printed label in response to a print instruction signal from an external device such as a computer. As shown in the figure, the label printer 1 mainly includes a substantially rectangular parallelepiped box-shaped housing 2, and an external interface 5 that receives a print instruction signal from an external device is provided in a part of the housing 2. .

  In the following description, the three-dimensional XYZ orthogonal coordinates shown in the figure are used as appropriate when indicating the direction and direction. The XYZ axes are fixed relative to the housing 2. Here, the X-axis and Y-axis directions are the horizontal direction, and the Z-axis direction is the vertical direction (the + Z side is the upper side). Further, the Y-axis direction is the depth direction (the -Y side is the front side and the + Y side is the back side).

  On the front side of the housing 2, a label issuing port 21 for sending out printed labels is formed, and a label tray 22 for accumulating issued labels is provided. Label printing is performed in the label printing unit 3 inside the housing 2. The label printing unit 3 stores a long label paper LP, and prints a label included in the label paper LP by a print head 41.

  FIG. 2 is a diagram illustrating a schematic configuration of the label printing unit 3 as viewed from the X-axis side. As shown in the figure, the label printing unit 3 accommodates a long label sheet LP including a plurality of unprinted labels LB that are continuously pasted on the label mount LM. The configuration of the label printing unit 3 is roughly divided into a print head 41 that prints such a label LB, a holding and conveying unit 30 that holds and conveys the label paper LP, and a label cutter 42 that cuts the label paper LP. .

  The print head 41 is constituted by a thermal head provided with a plurality of heating elements in a line shape along the X-axis direction. The print head 41 selectively blackens the surface of the label LB as the thermal paper by the selective heat generation of the plurality of heating elements, and forms the print content on the label LB.

  The holding and conveying unit 30 includes a label holding shaft 31, a guide roller 32, and a platen roller 33. The unprinted label paper LP is held on the label holding shaft 31 in a state of being wound in a roll shape around the paper tube LC serving as a core material. At the time of storage, the label holding shaft 31 supported so as to be rotatable about the shaft center is fitted into the paper tube LC of the label paper LP. As a result, the label paper LP is rotatable about the axis of the label holding shaft 31, and one end on the non-fixed side can be fed out. Hereinafter, the label paper LP in a roll state is referred to as “label roll”.

  The platen roller 33 is disposed to face the print head 41 with the conveyance path for the label paper LP interposed therebetween. A position P1 between the platen roller 33 and the print head 41 on the transport path of the label paper LP is a position where printing is actually performed (hereinafter referred to as “print position”). That is, printing is performed by the plurality of heating elements of the print head 41 on the label LB present at the printing position P1.

  The guide roller 32 is fixedly disposed rotatably at a predetermined position on the back side (+ Y side) of the print head 41. The guide roller 32 is in contact with the label sheet LP on the lower side thereof, and serves as a path defining member that defines a part of the conveyance path of the label sheet LP from the label holding shaft 31 to the printing position P1 (also FIG. 1). reference.). The label paper LP fed from the label roll held by the label holding shaft 31 is first conveyed to the guide roller 32, and after the direction of conveyance is changed along the outer periphery of the guide roller 32, the printing position P1 is further increased. Will be conveyed.

  Such conveyance of the label paper LP is performed by rotational driving of the platen roller 33. A stepping motor 34 is connected to the platen roller 33, and the platen roller 33 is rotationally driven by the driving of the stepping motor 34. Since the label paper LP is physically sandwiched between the platen roller 33 and the print head 41 at the printing position P1, the label paper LP is conveyed according to the rotational drive of the platen roller 33.

  In a normal printing operation, the label paper LP is fed from the label roll held on the label holding shaft 31 by the rotational drive of the platen roller 33, and the direction of the arrow AR1 toward the label issuing port 21 (hereinafter referred to as “forward conveyance”). Direction)). The platen roller 33 can also be rotated in the reverse direction. When the platen roller 33 rotates in the reverse direction, the label paper LP is in the direction of the arrow AR2 opposite to the forward conveyance direction (hereinafter referred to as “reverse conveyance direction”). ). When the platen roller 33 is not rotated, the label paper LP is fixed while being pressed between the platen roller 33 and the print head 41 at the printing position P1.

  The label cutter 42 cuts the label paper LP, and is disposed in the vicinity of the label issuing port 21 on the front surface side (−Y side) of the print head 41 so as to be driven in the vertical direction (Z-axis direction). The label paper LP that has been printed by the print head 41 is sent out of the housing 2 from the label issuing port 21. When a length corresponding to one label LB is sent, the label cutter 42 is moved toward the label paper LP, and the label paper LP is cut. As a result, the printed label LB is separated from the long label paper LP and can be handled for each label LB. The separated label LB is placed on the label tray 22.

  Further, inside the housing 2 of the label printer 1, there is provided a control unit that comprehensively controls the operation of each processing unit of the label printer 1. FIG. 3 is a functional block diagram showing the electrical configuration of the label printer 1 including such a control unit 10.

  The control unit 10 includes a microcomputer. More specifically, the control unit 10 is backed up by a battery, which is a CPU 11 that performs various arithmetic processes, a ROM 12 that stores a control program, a RAM 13 that is a work area for arithmetic processes, and a nonvolatile memory that stores various data. An SRAM 14 and a timer 15 having a time measuring function are provided, and these are electrically connected to each other via a bus line 6.

  Further, the external interface 5 described above is electrically connected to the bus line 6, and a print instruction signal or the like input from the external device 9 via the external interface 5 can be handled by the control unit 10. Further, the print head 41, the label cutter 42, and the stepping motor 34 of the label printing unit 3 are also electrically connected to the bus line 6, and these units operate under the control of the control unit 10.

  Various control functions of the control unit 10 are realized by the CPU 11 performing arithmetic processing according to a control program stored in the ROM 12 in advance.

<2. About Carl>
As described above, the label paper LP is conveyed linearly (that is, at the shortest distance) from the label holding shaft 31 to the guide roller 32 and from the guide roller 32 to the printing position P1 in the label printing unit 3 ( (See FIG. 2). At this time, the tension of the label paper LP is applied to the guide roller 32, and the portion of the label paper LP that contacts the guide roller 32 is deformed into a substantially circular shape along the outer peripheral shape of the guide roller 32.

  In FIG. 2, one label LT that is in contact with the guide roller 32 is deformed. For this reason, if the printing is not performed and left in the state shown in FIG. 2 for a while, the label LT has a curl (a state in which it is difficult to return the deformed substantially circular shape to the original linear shape: so-called “癖”). Will occur.

  Then, when printing is continued after such curl has occurred in the label LT, “positional deviation” or “fading” of the print content may occur with respect to the label LT, and print quality may be deteriorated. . Further, if the label sheet LP is cut immediately before the curled label LT, the label LT is not sent out from the label issuing port 21 due to entering between the housing 2 and the label cutter 42, etc. There is a possibility of clogging. Further, there is a possibility that a cutting failure by the label cutter 42 may occur due to curling.

  In the label printer 1 of the present embodiment, in order to eliminate these adverse effects caused by curling, the label paper LP is slightly fed out from the label roll held on the label holding shaft 31 after the printing of the label LB is completed. The tension of the label paper LP applied to the guide roller 32 is eased to prevent curling. Below, operation | movement of the label printer 1 of such this Embodiment is demonstrated.

<3. Operation>
FIG. 4 is a diagram showing an operation flow of the label printer 1. Since the label printer 1 prints a label in response to a print instruction signal from an external device, when the label printer 1 is activated, it enters a state of waiting for the input of the print instruction signal (step S11).

  When the print instruction signal is input (Yes in step S11), the label printing unit 3 prints the label LB under the control of the control unit 10 based on the image data included in the print instruction signal. That is, while the label paper LP is being conveyed in the forward conveyance direction by the platen roller 33, the heating elements of the print head 41 are selectively heated, thereby forming the print content on the label LB (step S12).

  When the printing of the label LB is completed and the printing operation of the print head 41 is stopped, the label cutter 42 is driven, and the label sheet LP including the printed label LB becomes a long sheet including the unprinted label LB. Cut from the label paper LP. As a result, the printed label LB is placed on the label tray 22 (step S13).

  On the other hand, as a preparatory operation for relaxing the tension of the label paper LP, the timer 15 starts measuring time from the time when the printing of the label LB is completed (when the operation of the print head 41 is stopped) (step S14). Thereby, the elapsed time from the point of time when printing of the label LB is completed is counted.

  After that, the timer 15 waits until a predetermined time (for example, 5 to 30 seconds) elapses (No in step S16). If the next print instruction signal is input before the predetermined time elapses (Yes in step S15), the timer 15 stops the time measurement operation, returns to step S12, and re-labels. LB printing is performed.

  On the other hand, when the time measured by the timer 15 has passed the predetermined time without inputting the print instruction signal (that is, when the predetermined time has passed since the most recent printing completion) (Yes in step S16), the guide roller The operation of relieving the tension of the label paper LP on 32 is controlled by the control unit 10.

  That is, first, the platen roller 33 is rotationally driven, and the label paper LP positioned at the printing position P1 is conveyed by a predetermined distance in the forward conveyance direction (step S17). As a result, the label sheet LP is pulled out from the label roll held on the label holding shaft 31 by a predetermined distance.

  Subsequently, the platen roller 33 is rotationally driven in the reverse direction, and the label paper LP positioned at the printing position P1 is conveyed by a predetermined distance in the reverse conveyance direction (step S18). This transport distance is the same as the transport distance of the label paper LP transported in step S17.

  Through the operations of these steps S17 and S18 (hereinafter referred to as “tension relaxation operation”), the label paper LP is fed out from the label roll by a predetermined distance. Accordingly, the length of the portion of the label paper LP existing in the transport path of the label paper LP from the label holding shaft 31 to the printing position P1 is longer than the shortest distance that is the linear distance of the transport path. As a result, as shown in FIG. 5, the portion of the label paper LP existing in the transport path is bent as a whole, and the tension of the label paper LP applied to the guide roller 32 is relieved.

  As can be seen from a comparison between FIG. 2 and FIG. 5, the label LT that has been largely deformed in contact with the guide roller 32 in FIG. 2 before the tension relaxation operation is shown in FIG. 5 after the tension relaxation operation. The degree of deformation is also reduced by being separated from the distance. Therefore, even if it is left in the state shown in FIG. 5 for a while, the curl does not occur in the label LT.

  After such a tension relaxation operation, the label printer 1 again enters a state of waiting for the input of a print instruction signal (return to step S11) (see FIG. 4). When the next print instruction signal is input (Yes in step S11), the label LB is printed again. As described above, in the tension relaxation operation, the transport distance of the label paper LP transported in the forward transport direction is the same as the transport distance of the label paper LP transported in the reverse transport direction. For this reason, the portion of the label paper LP existing at the printing position P1 is the same before and after the tension relaxation operation. Therefore, even if printing of the label LB is performed again after the tension relaxation operation, the printing contents can be normally continued without causing any positional deviation of the printing contents.

  As described above, in the label printer 1, when the print head 41 is not printed, the label sheet LP is placed on the label holding shaft 31 so that the portion of the label sheet LP in the transport path is longer than the shortest distance of the transport path. It is paid out from. Accordingly, since the tension of the label paper LP applied to the guide roller 32 is relaxed, the occurrence of curling in the label paper LP can be effectively prevented. As a result, it is possible to eliminate deterioration of print quality such as “positional deviation” and “blur” of print contents, paper jam at the label issuing port 21, and cutting failure due to the label cutter 42, which are harmful effects caused by curling. It will be possible.

  Further, since the tension of the label paper LP is relaxed by driving the platen roller 33 which is a normal transport means for transporting the label paper LP from the label holding shaft 31 to the printing position P1, in order to prevent the occurrence of curling, No operation or special mechanism is required, and the tension of the label paper LP can be easily relaxed.

  In addition, since the transport distance of the label paper LP in the forward transport direction and the transport distance of the label paper LP in the reverse transport direction in the tension relaxation operation are the same, the label that was present at the printing position before the tension relaxation operation. The portion of the paper LP exists at the printing position even after the tension relaxation operation, and the print content does not shift from the original position by the tension relaxation operation.

  In addition, since the tension of the label sheet LP is relaxed in response to the elapse of a predetermined time from the most recent printing completion time, the operation of relaxing the tension can be automatically performed without the user being aware of it. .

<4. Other embodiments>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments (hereinafter referred to as “representative embodiments”), and various modifications are possible. Hereinafter, such other embodiments will be described.

<4-1. Winding method>
The technology described in the representative embodiment can be applied to any printing apparatus that prints on a long print sheet. In either case, the occurrence of curling in the label paper LP can be effectively prevented, so that “positional displacement” and “blurring” of the print content can be eliminated, and the print quality can be improved.

  For example, as shown in FIG. 6, there is provided a label printer 1a that is not provided with a cutting mechanism for label paper LP, and issues only from a printed label LB from a label issuing port 21 while being peeled from a label mount LM. Also good.

  The configuration of the label printing unit 3 of the label printer 1a is the same as that shown in FIG. 2 except that the label cutter 42 is not provided and the peeling member 35 and the mount take-up unit 36 are provided. The peeling member 35 is provided in the vicinity of the label issuing port 21 and functions to peel the printed label LB from the label mount LM. Further, the mount winding unit 36 is connected to a DC motor 37 and functions to wind up the label sheet LP from which the printed label LB is peeled off and becomes only the label mount LM. Even in such a label printer 1a, it is possible to perform an operation of relaxing the tension of the label paper LP applied to the guide roller 32 by driving the platen roller 33 as in the representative embodiment.

  By the way, the mount winding unit 36 of such a label printer 1a generally winds the label sheet LP which is only the label mount LM with a constant torque. However, since the diameter of the label paper LP already wound around the mount winding portion 36 is different between the start of winding and the end of winding, even if the mount winding portion 36 rotates with a constant torque, the peeling member The tension applied to 35 is not constant. Such a change in tension affects the transport amount of the label paper LP by the platen roller 33, and as a result, the printing position may be shifted.

  For this reason, the torque may be variably controlled by performing ratio control by PWM (Pulse Width Modulation / pulse width modulation method) for the torque of the DC motor 37 of the mount winding unit 36. More specifically, the transport amount of the label paper LP by the platen roller 33 is detected by a label sensor. Then, the detected transport amount is compared with a predetermined set value. If an error occurs, the torque of the DC motor 37 is adjusted by increasing or decreasing the ratio according to the error. As a result, the tension applied to the peeling member 35 can be made constant from the start of winding to the end of winding, and the conveyance amount of the label paper LP by the platen roller 33 can also be made constant. As a result, the positioning accuracy and printing accuracy of the printing position can be improved.

<4-2. Rotation of label holding shaft>
In the representative embodiment, the label holding shaft 31 is rotatable (follows rotation). However, the label holding shaft 31 may be actively rotated by connecting a motor or the like. In this case, even when the print head 41 is not printing, the label paper LP is fed out by rotating the label holding shaft 31 in the direction in which the label paper LP is fed out, and the tension of the label paper LP applied to the guide roller 32 is alleviated. Good. Also by this, the portion of the label paper LP in the transport path becomes longer than the shortest distance of the transport path, and the curling of the label paper LP can be effectively prevented.

  Further, when the tension is relaxed by the active rotation operation of the label holding shaft 31 as described above, if the platen roller 33 is not rotated during the tension relaxation operation, the label paper LP is moved to the platen roller 33 at the printing position P1. And the print head 41 are fixed in a pressed state. For this reason, even in this case, the portion of the label paper LP existing at the printing position P1 is the same before and after the tension relaxation operation, and the positional deviation of the printing content does not occur.

  When the label holding shaft 31 is actively rotated in this way, generally, as shown in FIG. 7, no positional deviation occurs between the label holding shaft 31 and the paper tube LC of the label roll. A stopper 71 for preventing displacement is formed on the label holding shaft 31.

  When such a mechanism is employed, as shown in FIG. 7, during normal operation, the label holding shaft 31 cooperates with a platen roller 33 (not shown) to feed the label paper LP in the forward transport direction (the direction of the arrow AR3). The label paper LP is conveyed. However, as shown in FIG. 8, when the amount of the label paper LP of the label roll decreases, the label holding shaft 31 carries a force (hereinafter referred to as “reverse carrying force”) for carrying the label paper LP in the reverse carrying direction (the direction of arrow AR4). Will be generated. Such reverse conveyance force becomes a load of conveyance in the forward conveyance direction and may adversely affect the drive system.

  For this reason, as shown in FIG. 9, a columnar member having no stopper 71 and having an outer diameter smaller than the inner diameter of the paper tube LC may be adopted as the label holding shaft 31. According to this, the label holding shaft 31 comes into contact with the paper tube LC only at the upper end position P2, and a space 79 is formed inside the paper tube LC.

  In this case as well, during normal operation, the label holding shaft 31 cooperates with the platen roller 33 (not shown) in the forward conveyance direction (arrow AR5) by the frictional force generated at the contact portion P2 with the paper tube LC. The label paper LP is conveyed in the direction of On the other hand, as shown in FIG. 10, when the amount of label paper LP on the label roll decreases, a reverse conveying force is generated in the reverse conveying direction (in the direction of arrow AR6) in this case as well, but the label holding shaft 31 and the paper tube Since slip occurs at the contact portion P2 with the LC, the reverse conveying force can be made relatively small. For this reason, it is possible to reduce the adverse effect on the drive system.

<4-3. Other variations>
In the representative form, a label printer using a label as a printing medium has been described as an example. However, for example, even a printing apparatus using paper other than a label as a printing medium, such as a receipt printer that prints a receipt, It is possible to apply a technique similar to the form.

  In the representative form, the thermal printer using the thermal head as the print head has been described. However, the present invention is not limited to this. For example, an ink jet printer using an ink jet head as the print head may be used as the representative form. Similar techniques can be applied.

  Further, in the representative form, the tension relaxation operation is performed in response to the elapse of a predetermined time from the most recent printing completion time, but in response to a predetermined operation (event) such as a user's button operation or power stop. A tension relaxation operation may be performed.

  Also, in a printing device that prints in response to a print instruction signal from an external device such as a representative form, if printing is not executed, whether the cause is on the external device side or the printing device side It may be difficult to grasp. For this reason, a buzzer (sound output means) and a patrol light (display means) are provided in the printing apparatus, and when a print instruction signal is normally received from an external apparatus, a sound is output from the buzzer and the patrol light is emitted. You may make it transmit that to a user. According to this, when the buzzer or the patrol light is driven but the printing is not executed, the user can recognize that the cause is on the printing apparatus side, and conversely, when the buzzer or the patrol light is not driven. Therefore, it can be recognized that the cause is on the external device side. Further, since the fact is transmitted to the user by driving the buzzer or the patrol light, even if the user is at a position away from the printing apparatus, it can be easily grasped.

  In addition, as long as it can be distinguished between the normal time and the abnormal time, any driving mode of the buzzer or the patrol light may be used. For example, the buzzer or the patrol light may be driven only when an abnormal print instruction signal is received from the external device, and the driving mode of the buzzer or the patrol light (the length of the sound, the pitch of the sound, the number of sound outputs, the light emission time) , Emission color, number of blinks, etc.) may be different between normal and abnormal.

It is a perspective view of a label printer. It is a figure which shows schematic structure of a label printing part. It is a figure which shows the electrical structure of a label printer with a functional block. It is a figure which shows the flow of operation | movement of a label printer. It is a figure which shows the mode of the label printing part after tension | tensile_strength operation | movement. It is a figure which shows another example of a structure of a label printing part. It is a figure which shows the mode of the vicinity of the label holding shaft which provided the stopper. It is a figure which shows the mode of the vicinity of the label holding shaft which provided the stopper. It is a figure which shows the mode of the vicinity of the label holding | maintenance axis | shaft which is not provided with a stopper. It is a figure which shows the mode of the vicinity of the label holding | maintenance axis | shaft which is not provided with a stopper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Label printer 3 Label printing part 21 Label issuing port 31 Label holding shaft 32 Guide roller 33 Platen roller 41 Print head 42 Label cutter

Claims (5)

A printing apparatus for printing on a long printing paper,
Holding means for holding the unprinted printing paper in a roll state;
A print head for printing on the printing paper present at a predetermined printing position conveyed from the holding means;
A path defining member that contacts the print sheet and defines a part of the transport path of the print sheet from the holding unit to the printing position;
Tension relaxation means for unwinding the printing paper from the holding means when the print head is not printing, and relaxing the tension of the printing paper applied to the path defining member;
A printing apparatus comprising: The printing apparatus according to claim 1,
The printing apparatus according to claim 1, wherein the tension relaxation unit is a conveyance unit that conveys the printing paper from the holding unit to the printing position. The printing apparatus according to claim 2,
The tension relaxation unit conveys the printing paper in a first direction in which the printing paper is fed out from the holding unit by a predetermined distance, and then moves the printing paper in a second direction opposite to the first direction. The printing apparatus is characterized in that the tension of the printing paper is relieved by carrying the same distance. The printing apparatus according to any one of claims 1 to 3,
The printing apparatus according to claim 1, wherein the tension relaxation means relaxes the tension of the printing paper when a predetermined time elapses after the operation of the print head is stopped. The printing apparatus according to any one of claims 1 to 4,
A cutting means that is disposed in the vicinity of an issuing port from which the printed printing paper is issued, and cuts the printed printing paper;
A printing apparatus, further comprising:

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