WO2015151367A1

WO2015151367A1 - Device and method for determining whether liner-free label has gotten caught in thermal printer

Info

Publication number: WO2015151367A1
Application number: PCT/JP2014/084375
Authority: WO
Inventors: 星　和行
Original assignee: サトーホールディングス株式会社
Priority date: 2014-03-31
Filing date: 2014-12-25
Publication date: 2015-10-08
Also published as: JP2015193155A

Abstract

A label-detecting sensor is provided downstream of a platen roller. The sensor distance, i.e. the distance between the platen roller and the label-detecting sensor, is less than the outer circumference of the platen roller. When an actual platen-roller rotation amount accompanying printing on a liner-free label exceeds a set platen-roller rotation amount corresponding to the aforementioned sensor distance, if the label-detecting sensor has not yet detected said liner-free label, the liner-free label is determined to have gotten caught in the platen roller.

Description

Mount determination device and method for determining unwrapped label in thermal printer

The present invention relates to a device for preventing the winding of a label without a mount and a method for setting the leading end of the label in a thermal printer, and in particular, there is no mount in a thermal printer capable of preventing the winding of the label without a mount in the forward or reverse direction. The present invention relates to a label winding prevention device and a label leading edge setting method.

Conventionally, as a strip-shaped label paper, there is a mountless label for resource saving without using a mount (release paper) for temporarily attaching an adhesive layer on the back side of the label base material. Printers (eg, thermal printers) have also been developed. JP3636476B discloses a printer that requires a label without a mount.

FIG. 7 is a schematic side view showing a thermal printer 1 as a comparative example. The thermal printer 1 includes a supply unit 3 for a label 2 without mount, a detection unit 4, a printing unit 5, a cutting unit 6, Have

The mountless label 2 is formed on the surface of the label substrate 7, as shown in the drawing with the enlarged cross-section thereof, the strip-shaped label substrate 7, the adhesive layer 8 formed on the back surface of the label substrate 7, and the label substrate 7. The lower layer side heat-sensitive color former layer 9 and the upper layer side release agent layer 10 are provided.

Therefore, even if the mountless label 2 is loaded into the supply unit 3 in a roll shape, the release agent layer 10 comes into contact with the adhesive layer 8, so that the inner layer side and the outer layer side of the roll adhere to each other. Therefore, the roll-less mountless label 2 can be fed out into the transfer path 11 from the upstream side to the downstream side in a band shape.

Guide rollers

12 and 13 are provided in the transfer path 11 so that the non-mounting label 2 can be guided.

A position detection mark (not shown) is printed in advance on the back surface of the label substrate 7 at a predetermined pitch.

The detection unit 4 has a mark sensor 14 and detects the position detection mark of the label 2 without mount so that the relative position of the label 2 without mount with respect to the printing unit 5 and the cutting unit 6 can be detected.

The printing unit 5 includes a thermal head 15 and a platen roller 16. The label 2 without a mount is supplied and sandwiched between the thermal head 15 and the platen roller 16, and is transported by rotation of the platen roller 16. Printing data can be supplied to the 15 heating elements 15 A to print a predetermined content on the surface of the label substrate 7.

The cutting unit 6 has a movable blade 17 and a fixed blade 18, cuts the label 2 without mount at a predetermined pitch, and issues it as a single leafless label 2A. After cutting the non-mounting label 2 by the cutting unit 6, the non-mounting label 2 is reversely transferred and kept waiting for the next printing. Specifically, the label leading end 2 B stands by in a state of protruding toward the cutting unit 6 from the position sandwiched between the thermal head 15 and the platen roller 16.

In addition, by forming perforations (not shown) at a predetermined pitch on the non-mounting label 2, the printed non-mounting label 2 is separated at the perforation without using a cutter, You can also

In the thermal printer 1 having such a configuration, a peelable material is used for the parts (guide roller 13, guide roller 12 if necessary) of the transfer path 11 that contacts the adhesive layer 8 on the back surface of the non-mounting label 2 and the platen roller 16. The surface treatment is performed so as to ensure non-adhesiveness by itself or to have a peelable (non-adhesive) surface. For example, a silicone rubber material is used as the platen roller 16.

However, when the thermal printer 1 is used continuously or for a long period of time, the non-adhesiveness of the platen roller 16 gradually decreases, and the non-mounting label 2 is easily stuck on the platen roller 16 and becomes entangled.

Further, even when the operation of the thermal printer 1 is stopped for a long time while the label 2 without the mount is sandwiched between the thermal head 15 and the platen roller 16, the label 2 without the mount is stuck on the platen roller 16.

FIG. 8 is an enlarged side view showing a state where the mountless label 2 is wound around the platen roller 16 when the platen roller 16 is transferred (forward transfer) in the forward direction (from upstream to downstream). As shown in FIG. 8, as a result of the printed non-mounting label 2, the label leading end 2 B sticks to the outer peripheral surface side (downstream outer surface) with the positive rotation of the platen roller 16. There will be a hindrance to the issuance and discharge of None Label 2.

It should be noted that the effort to peel off the non-mounting label 2 attached to the platen roller 16 is difficult. Even when the platen roller 16 is rotated in the reverse direction, the label 2 without mount is often stuck on the outer surface on the upstream side of the platen roller 16.

FIG. 9 shows a state in which the label 2 without the mount is wound around the platen roller 16 when the platen roller 16 is transferred in the reverse direction (reverse transfer from the downstream side to the upstream side, also referred to as back feed). FIG. After the printed first label without mount (not shown) is cut by the cutting unit 6, the subsequent label without mount 2 is reversely transferred to the printing start position in the printing unit 5, and the label leading end 2 B starts printing on the printing unit 5. In order to set the position, the platen roller 16 is rotated in the reverse direction. Since the supply unit 3 is not connected to the driving source and does not have a function of rewinding the label 2 without the mount, the label 2 without the mount 2 sags on the upstream side of the platen roller 16. In a normal state, the non-mounting label 2 sags gently on the upstream side of the guide roller 13 as indicated by a virtual line in FIG. On the other hand, when the adhesive layer 8 of the label 2 without mount is stuck on the platen roller 16, the platen roller 16 rotates in the reverse direction with the label 2 without mount being attached, and the label 2 without mount is indicated by the solid line in the figure. As shown in the figure, it is stuck on the outer peripheral surface on the upstream side and is wound up, which causes a problem in the next printing issue. This phenomenon becomes remarkable when the back feed length is long.

When the perforations (not shown) are formed on the non-mounting label 2 at a predetermined pitch, the stress associated with the sag is concentrated on the perforation portion having low rigidity, and the non-mounting label 2 bends or snakes greatly and gets caught. This may be further encouraged.

When the mountless label 2 is wound around the platen roller 16 as shown in FIG. 9, the reverse transfer distance itself is not so large, so that the subsequent measures are relatively easy.

However, in particular, when the label 2 without mount is wound around the platen roller 16 as shown in FIG. 8, the label 2 without mount is wound around the platen roller 16 unless it is noticed. As a result, not only will the subsequent countermeasures become large, but the outer circumference around the platen roller 16 will increase, adversely affecting the thermal head 15 and other parts, and the failure of the motor that drives the platen roller 16 to rotate. Is also worried.

The present invention has been considered in view of the above problems, and provides an apparatus and a method for determining the entrapment of a label without a mount in a thermal printer that can quickly determine that a label without a mount has been caught in a platen roller. The purpose is to do.

In the aspect of the present invention described below, attention is paid to providing a label detection sensor on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller.

According to the first aspect, there is no mount having a label base material, an adhesive layer formed on the back surface of the label base material, and a heat-sensitive color former layer and a release agent layer formed on the surface of the label base material. An apparatus for determining the inclusion of a label without a mount in a thermal printer that sandwiches the label between a thermal head and a platen roller, and transfers and prints the label from the upstream side to the downstream side of the transport path for the label without a mount. A label detection sensor is provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller, and the platen roller is rotated by the rotation of the platen roller along with the printing on the label without the mount. Even if the distance exceeds the set rotation distance of the platen roller corresponding to this sensor distance, this label detection is performed. If not detected None the mount label by the sensor, without the backing label it can be determined to be involved in the platen roller, entrainment determination device without mount labels in a thermal printer is provided.

According to the second aspect, there is no mount having a label base material, an adhesive layer formed on the back surface of the label base material, and a heat-sensitive color former layer and a release agent layer formed on the surface of the label base material. A method for determining whether a label without a mount is entrained in a thermal printer that sandwiches a label between a thermal head and a platen roller, and transfers and prints from the upstream side to the downstream side of the transfer path for the label without a mount. A label detection sensor is provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller, and the platen roller is actually printed when the platen roller is rotated and printed on the non-mounting label. Even if the dynamic rotation distance exceeds the set rotation distance of the platen roller corresponding to this sensor distance, If not detected None the mount label by Le detecting sensor, without the backing label is determined to have been caught in the platen roller, winding determination process without backing labels in a thermal printer is provided.

The platen roller has a winding prevention unit comprising a pair of left and right brackets positioned on the left and right ends of the platen roller, and a downstream winding prevention member that spans between the brackets. The platen roller can be disposed downstream of the platen roller, and can be guided so as to separate the mountless label from the platen roller while being in contact with the adhesive layer on the back surface of the mountless label. At least one of the pair of brackets is formed with a roller engaging hole that engages with a roller shaft of the platen roller, and at least one of the pair of left and right brackets is provided on the platen roller. The relative position can be fixed.

The platen roller has a winding prevention unit including a pair of left and right brackets positioned on the left and right ends of the platen roller, and an upstream winding prevention member that spans between the brackets. The platen roller can be disposed upstream of the platen roller, and the label without the mount can be guided in the direction of the platen roller while being in contact with the adhesive layer on the back surface of the label without the mount. At least one of the brackets is formed with a roller engagement hole that engages with a roller shaft of the platen roller, and at least one of the pair of left and right brackets is relative to the platen roller relative to the entrainment prevention unit. The position can be fixed.

The wrapping prevention unit is a print that can sandwich the mountless label between the thermal head and the platen roller in a space region between the upstream wrapping prevention member and the downstream wrapping prevention member. An area can be formed.

In the winding determination device and the winding determination method for a baseless label in the thermal printer according to the above aspect, a label detection sensor is provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller. If the actual rotation distance of the platen roller due to printing on the label without a mount exceeds the set rotation distance of the platen roller corresponding to this sensor distance, the label detection sensor will not detect a label without a mount It can be determined that the label without a mount is wound around the platen roller.

In particular, according to the first embodiment of the thermal printer according to the thermal printer, the label detection sensor provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller detects the label without the mount. With the simple configuration of determining whether or not there is, it is possible to determine the phenomenon of the label without a mount on the platen roller.

In particular, according to the second aspect of the thermal printer according to the method for determining the winding of a label without a mount, detection of a label without a mount by a label detection sensor provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller. A simple method of determining the presence or absence of the label can determine the phenomenon of the label without the mount on the platen roller, so that the label without the mount on the platen roller can be prevented from being further wound. .

FIG. 1 is an enlarged cross-sectional side view of a mountless label winding determination device 20 in the thermal printer according to the first embodiment of the present invention. FIG. 2 is a perspective view of a state in which the winding prevention unit is assembled to the platen roller. FIG. 3 is a perspective view of the entrainment prevention unit. FIG. 4 is an enlarged side cross-sectional view of a mountless label winding determination device in the thermal printer according to the second embodiment of the present invention. FIG. 5 is a perspective view of a state in which the winding prevention unit is assembled to the platen roller. FIG. 6 is a perspective view of the roll-in preventing unit. FIG. 7 is a schematic side view showing a thermal printer as a comparative example. FIG. 8 is an enlarged side view showing a state in which the label 2 without mount is wound around the platen roller when the platen roller is transferred (forward transfer) in the forward direction (from the upstream side to the downstream side). FIG. 9 is an enlarged side view illustrating a state in which the label without a mount is wound around the platen roller when the platen roller is transferred in the reverse direction (from the downstream side to the upstream side) (reverse transfer).

In the embodiment of the present invention, on the downstream side of the platen roller, a label detection sensor is provided at a sensor distance shorter than the outer peripheral length of the platen roller, and by comparing the actual rotation distance of the platen roller with the set rotation distance, When a label without a mount is not detected by this label detection sensor, a label determination device and a label determination method for a label without a mount in a thermal printer that can determine that a label without a mount is wound on a platen roller are realized. .

Hereinafter, the label determination device 20 and the label determination method for the non-mounting label in the thermal printer according to the first embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIGS. 7 to 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is an enlarged side cross-sectional view of the winding determination device 20, and the winding determination device 20 includes a winding prevention unit 21, a drive motor 22, a label detection sensor 23, and a control unit 24. .

FIG. 2 is a perspective view of the state in which the winding prevention unit 21 is assembled to the platen roller 16, and FIG. 3 is a perspective view of the winding prevention unit 21, and the winding prevention unit 21 includes both left and right ends of the platen roller 16. It consists of a pair of left and right brackets 25 located on the part side, and an upstream wrapping prevention member 26 and a downstream wrapping prevention member 27 that span between the brackets 25.

In particular, as shown in FIG. 3, a roller engagement hole 29 that engages with the roller shaft 28 of the platen roller 16 is formed in one of the pair of left and right brackets 25, and the other is provided on the roller shaft 28. The engaging arcuate cutout 30 is formed. That is, the anti-rolling unit 21 can be directly attached to the platen roller 16 to maintain the relative position of each other over a long period of time, and to keep the deviation between each other to a minimum.

At least one of the pair of left and right brackets 25 (right side in FIG. 3) can fix the relative position of the winding prevention unit 21 with respect to the platen roller 16. Specifically, a fixing hole 31 for fixing the bracket 25 to the printer body 1 A of the thermal printer 1 is formed in at least one of the pair of left and right brackets 25.

That is, by fixing the bracket 25 to the printer main body 1A using a fixing screw 32 or the like passed through the fixing hole 31, the platen roller 16 and the bracket 25 (that is, the winding prevention) that are also fixed to the printer main body 1A so as to be rotatable. The relative position with the unit 21) can be maintained.

The upstream side roll-in preventing member 26 is made of, for example, a metal plate material, and has a non-adhesive treatment such as applying a release agent on the surface thereof.

The upstream side roll-in preventing member 26 is disposed on the upstream side of the platen roller 16, and the downstream side edge 26 A is disposed close to and opposed to the platen roller 16. The non-mounting label 2 can be guided toward the thermal head 15 and the platen roller 16 while being in contact with the layer 8.

The downstream entrainment preventing member 27 is made of, for example, a metal plate material, and a non-adhesive treatment such as application of a release agent is performed on the surface thereof.

The downstream wrapping prevention member 27 is disposed on the downstream side of the platen roller 16, and the upstream side edge 27 A is opposed to the platen roller 16 so as to face the adhesive. The non-mounting label 2 can be guided away from the platen roller 16 while in contact with the layer 8.

Further, the upstream side wrapping prevention member 26 and the downstream side wrapping prevention member 27 extend to the back surface side over the entire width direction of the mountless label 2.

The upstream wrapping prevention member 26 and the downstream wrapping prevention member 27 form the mountless label 2 on the platen roller 16 by forming the respective leading end portions facing the platen roller 16 at an acute angle. Furthermore, it can be made difficult to entrain.

In particular, as shown in FIG. 1, the entanglement preventing unit 21 is located in a space region between the downstream end edge 26 A of the upstream side entanglement preventing member 26 and the upstream end edge 27 A of the downstream side entanglement preventing member 27. A print area 33 in which the mountless label 2 can be sandwiched between the thermal head 15 and the platen roller 16 can be formed. The heating element 15A of the thermal head 15 is located in the printing area 33, and the thermal head 15 can transfer and print by holding the mountless label 2 between the outer peripheral surface of the platen roller 16 and a predetermined pressing force.

The drive motor 22 is a step motor, for example, and can drive the platen roller 16 to rotate at a predetermined rotation pitch.

The label detection sensor 23 may be any type of sensor such as a transmission type or a reflection type, and can detect the label leading end 2B of the mountless label 2 printed and issued by the printing unit 5.

The label detection sensor 23 is provided on the downstream side of the platen roller 16 with a sensor distance D1 shorter than the outer peripheral length of the platen roller 16 (2πR if the radius of the platen roller 16 is R). However, the sensor distance D1 is a distance from the heating element 15A of the thermal head 15 to the label detection sensor 23.

The control unit 24 controls the drive motor 22, the label detection sensor 23, the detection unit 4, the printing unit 5, the cutting unit 7, and the like.

The set rotation distance D2 of the platen roller 16 is set as an equivalent distance corresponding to the sensor distance D1 of the label detection sensor 23.

Therefore, the control unit 24 determines that the actual rotation distance D3 of the platen roller 16 accompanying the printing on the non-mounting label 2 by the rotation of the platen roller 16 exceeds the set rotation distance D2 of the platen roller 16 corresponding to the sensor distance D1. However, if the label 2 without the mount is not detected by the label detection sensor 23, it can be determined that the label 2 without the mount is caught in the platen roller 16.

However, each of the sensor distance D1, the set rotation distance D2, and the actual movement rotation distance D3 is recognized and managed in terms of the number of rotation steps of the platen roller 16 by the drive motor 22.

In the thermal printer 1 and the wrapping determination device 20 having such a configuration, as shown in FIG. 1 in particular, in the normal single-leaf mountless label 2A issuance operation, the mountless label 2 is fed from the guide roller 13 to the upstream wrapping prevention member 26. To the printing area 33 and printing is performed on the label 2 without the mount, and the label 2 without the mount that has left the printing area 33 is guided by the downstream wrapping prevention member 27 and is not caught by the platen roller 16. The cutting part 6 can be reached.

In the operation in which the non-mounting label 2 is cut by the cutting unit 6 and the single-sheet non-mounting label 2A is issued and then the non-mounting label 2 is reversely transferred to the printing start position in the printing area 33, the non-mounting label 2 is upstream. It is guided by the anti-roll member 26 and is not caught by the platen roller 16.

The printed boardless label 2 is cut by the cutting portion 6 disposed on the downstream side of the downstream side roll-in preventing member 27 to form a single-sheet boardless label 2A, and the platen roller 16 is rotated in the reverse direction. In the state in which the upstream label 2 on the upstream side of the single-sheet-less label 2A is reversely transferred to the upstream side, and the label leading end 2B of the label 2 on the downstream side is disposed on the downstream wrapping prevention member 27 (see FIG. 1). (Refer to the line) Stop reverse transfer of label 2 without mount.

That is, in a state where the label end portion 2B of the no-mounting label 2 is disposed on the downstream-side anti-winding member 27 of the anti-winding unit 21, the no-mounting label 2 is sandwiched between the thermal head 15 and the platen roller 16, The print area 33 can be set.

If the print standby time in the thermal printer 1 becomes long, the platen roller 16 is slightly reversely rotated at the start of the next printing to back-feed the label 2 without the mount, and then the leading edge of the label. By arranging and setting the portion 2B so as to be placed on the downstream side wrap-around preventing member 27, it is possible to avoid sticking the label 2 without the mount 2 to the platen roller 16 at the start of the printing operation.

However, in spite of the provision of the wrapping prevention unit 21 as described above, in the unlikely event that the label leading end 2B of the non-mounting label 2 is stuck to the outer periphery of the platen roller 16 and is wound on the platen roller 16, the platen Even if the actual rotation distance D3 of the platen roller 16 due to the printing on the non-mounting label 2 due to the rotation of the roller 16 exceeds the set rotation distance D2 of the platen roller 16 corresponding to the sensor distance D1, the label detection sensor 23 causes the mount. When the no label 2 is not detected, it can be determined that the non-mounting label 2 is caught in the platen roller 16.

In the present embodiment, the upstream side wrap-around preventing member can be made of a shaft material.

That is, FIG. 4 is an enlarged side cross-sectional view of the unwrapped label winding determination device 40 in the thermal printer according to the second embodiment of the present invention. The winding determination device 40 includes a winding prevention unit 41, and The drive motor 22, the label detection sensor 23, and the control unit 24 described above are included.

FIG. 5 is a perspective view of a state in which the winding prevention unit 41 is assembled to the platen roller 16, and FIG. 6 is a perspective view of the winding prevention unit 41, and the winding prevention unit 41 includes both left and right ends of the platen roller 16. A pair of left and right brackets 25 located on the part side, a cross-sectional circular shape spanning between the brackets 25, and an upstream wrapping prevention member 42 and a downstream wrapping prevention member 27 formed of a metal shaft member, It consists of.

The surface of the upstream side roll-in preventing member 42 is subjected to non-adhesive treatment such as applying a release agent, and can rotate with respect to the pair of left and right brackets 25 to smoothly guide the non-mounting label 2. It is.

Since the upstream winding prevention member 42 is the same as the above-described winding determination device 20 (FIG. 1) except that it is made of a shaft material, the same parts are denoted by the same reference numerals.

In the winding determination device 40 having such a configuration, as in the case of the winding determination device 20, in the printing operation of the non-mounting label 2 by the forward and reverse rotation of the platen roller 16 and the setting operation of the non-mounting label 2 to the printing position, A stable transfer function can be exhibited without the mountless label 2 being caught by the platen roller 16.

However, if the label leading end 2B of the label 2 without mount is stuck on the outer periphery of the platen roller 16 and is caught in the platen roller 16, the actual rotation distance D3 of the platen roller 16 becomes the sensor distance D1. Even if the set rotation distance D2 of the corresponding platen roller 16 is exceeded, when the label 2 without the mount is not detected by the label detection sensor 23, it can be determined that the label 2 without the mount is caught in the platen roller 16.

In particular, since the upstream wrapping prevention member 42 is made of a shaft material, the contact resistance with the mountless label 2 that is guided in contact with the upstream wrapping prevention member 42 is small and more stable. Can be prevented.

The embodiment of the present invention has been described above, but the above embodiment is merely a part of an application example of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

This application claims priority based on Japanese Patent Application No. 2014-72564 filed with the Japan Patent Office on March 31, 2014, the entire contents of which are incorporated herein by reference.

Claims

A label substrate;
An adhesive layer formed on the back surface of the label substrate;
A mountless label having a thermosensitive color former layer and a release agent layer formed on the surface of the label substrate is sandwiched between a thermal head and a platen roller, and from the upstream side of the transport path of the mountless label. A device for determining whether or not to mount a label without a mount in a thermal printer that transfers and prints toward the downstream side,
A label detection sensor is provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller,
Even when the actual rotation distance of the platen roller due to the printing on the label without a mount due to the rotation of the platen roller exceeds the set rotation distance of the platen roller corresponding to the sensor distance, the label detection sensor causes the mount to When no label is detected, it can be determined that the label without the mount is wound on the platen roller.
A device for determining the unwrapped label of thermal printers.
A roll-up determination device for a label without a mount in the thermal printer according to claim 1,
A pair of left and right brackets located on the left and right ends of the platen roller;
A downstream-side winding prevention member that spans between the brackets, and a winding prevention unit comprising:
The downstream wrap-around preventing member is disposed on the downstream side of the platen roller, and separates the mountless label from the platen roller while being in contact with the adhesive layer on the back surface of the mountless label. Can be guided to
At least one of the pair of left and right brackets has a roller engagement hole that engages a roller shaft of the platen roller, and
At least one of the pair of left and right brackets can fix the relative position of the entanglement preventing unit with respect to the platen roller.
A device for determining the unwrapped label of thermal printers.
A roll-up determination device for a label without a mount in the thermal printer according to claim 1,
A pair of left and right brackets located on the left and right ends of the platen roller;
An upstream side anti-winding member that spans between the brackets, and an anti-winding unit comprising:
The upstream side roll-in preventing member is disposed on the upstream side of the platen roller, and guides the label without a mount in the direction of the platen roller while being in contact with the adhesive layer on the back surface of the label without the mount. Is possible,
At least one of the pair of left and right brackets has a roller engagement hole that engages a roller shaft of the platen roller, and
At least one of the pair of left and right brackets can fix the relative position of the entanglement preventing unit with respect to the platen roller.
A device for determining the unwrapped label of thermal printers.
A winding determination device for a label without a mount in the thermal printer according to any one of claims 1 to 3,
The wrapping prevention unit is a print that can sandwich the mountless label between the thermal head and the platen roller in a space region between the upstream wrapping prevention member and the downstream wrapping prevention member. An area can be formed,
A device for determining the unwrapped label of thermal printers.
A label substrate;
An adhesive layer formed on the back surface of the label substrate;
A mountless label having a thermosensitive color former layer and a release agent layer formed on the surface of the label substrate is sandwiched between a thermal head and a platen roller, and from the upstream side of the transport path of the mountless label. A method for determining the winding of a label without a mount in a thermal printer that transfers and prints toward the downstream side,
A label detection sensor is provided on the downstream side of the platen roller at a sensor distance shorter than the outer peripheral length of the platen roller,
Even when the actual rotation distance of the platen roller due to the printing on the label without a mount due to the rotation of the platen roller exceeds the set rotation distance of the platen roller corresponding to the sensor distance, the label detection sensor causes the mount to When no label is detected, it is determined that the label without the mount is wound on the platen roller.
A method for determining the presence of labels without mounts in thermal printers.