label printer

Abstract

To provide a technology capable of suppressing waste of labels provided with wireless tags in a label printer. [Solution] A CPU 11 of a label printer 1 performs a remaining length determination by comparing a necessary length x with a remaining length m for a tape A downstream of a cutting position 7 in the forward direction. If the remaining length m is longer than the necessary length x, a reverse transport process is completed for a passing RF tag located at the most downstream position in the forward direction, and then a label production process is started. On the other hand, if it is determined that the remaining length m is shorter than the necessary length x, a rescue target calculation process is performed to calculate rescueable RF tags that are passing RF tags located further upstream than the passing RF tag located at the most downstream position in the forward direction and that can move in the reverse direction to the communication position.

Description

[Technical Field]

[0001] The technical field disclosed herein relates to label printers. [Background technology]

[0002] Conventionally, there are known label printers that always feed the label paper by the length of one label to determine the print start position. With such label printers, the paper feed to determine the print start position before starting printing can result in one label being wasted. In response to this, for example, Patent Document 1 discloses a technology that reduces label waste by feeding the label paper back when the power is turned on, and then feeding the paper by the length of one label to determine the print start position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-062885 Summary of the Invention [Problem to be solved by the invention]

[0004] The printing targets of a label printer may include labels equipped with wireless tags such as RF tags. Patent Document 1 does not disclose a technology for reducing label waste when printing on labels equipped with wireless tags. Therefore, there is room for improvement in the technology for printing on labels equipped with wireless tags. [Means for solving the problem]

[0005] A label printer according to one aspect of the disclosed technology includes: a storage unit that stores a roll of a medium, the medium having a long release paper and a plurality of labels attached to the release paper, the labels having wireless tags; a thermal head for forming an image on the label of the medium; a platen roller that forms a nip between itself and the thermal head, and when rotating forward, conveys the medium sandwiched in the nip in a forward direction from the storage unit to the thermal head, and when rotating reverse, conveys the medium sandwiched in the nip in a reverse direction from the thermal head to the storage unit; a motor capable of rotating the platen roller in the forward direction or the reverse direction; an antenna capable of communicating with the wireless tag at a communication position upstream of the nip in the forward direction; a cutter that cuts the medium at a cutting position downstream of the nip in the forward direction; a control unit, The control unit a label production process in which, while conveying the medium in the forward direction, the thermal head forms an image on the label and the antenna communicates with the wireless tag; a reverse transport process of transporting the medium in the reverse direction until a passing wireless tag, which is the wireless tag that has moved in the forward direction beyond the communication position, reaches at least the communication position; The control unit further includes, before starting the label production process, For the medium downstream of the cutting position in the forward direction, a remaining length determination is performed by comparing a necessary length, which is a length necessary to maintain the medium held by the nip when the passing wireless tag located furthest downstream in the forward direction is transported in the reverse direction until it reaches the communication position, with a remaining length, which is the length from the cutting position to the tip of the medium, which is the end opposite to the storage section side; When it is determined that the remaining length is longer than the required length by the remaining length determination, the reverse conveyance process is performed for the passing RFID tag located at the most downstream position in the forward direction, and then the label production process is started. When the remaining length determination determines that the remaining length is shorter than the required length, a rescue target calculation process is performed to calculate rescueable radio tags that are passing radio tags located further upstream than the passing radio tag located furthest downstream in the forward direction and that can move in the reverse direction until they reach the communication position, The control unit further includes: When the salvageable wireless tag is calculated by the salvage target calculation process, the reverse transport process is executed for the salvageable wireless tag, and then the label production process is started. If the rescueable wireless tag is not calculated by the rescue target calculation process, the reverse conveyance process is not executed and the label production process is started. It is configured as follows.

[0006] A label printer according to another aspect of the present disclosure, which is different from the above-described aspect, includes: a storage unit that stores a roll of a medium, the medium having a long release paper and a plurality of labels attached to the release paper, the labels having wireless tags; a thermal head for forming an image on the label of the medium; a platen roller that forms a nip between itself and the thermal head, and when rotating forward, conveys the medium sandwiched in the nip in a forward direction from the storage unit to the thermal head, and when rotating reverse, conveys the medium sandwiched in the nip in a reverse direction from the thermal head to the storage unit; a motor capable of rotating the platen roller in the forward direction or the reverse direction; an antenna capable of communicating with the wireless tag at a communication position upstream of the nip in the forward direction; a cutter that cuts the medium at a cutting position downstream of the nip in the forward direction; a medium sensor capable of detecting the presence or absence of the medium at a medium detection position downstream of the nip in the forward direction; a control unit, The control unit a label production process in which, while conveying the medium in the forward direction, the thermal head forms an image on the label and the antenna communicates with the wireless tag; a reverse transport process of transporting the medium in the reverse direction until a passing wireless tag, which is the wireless tag that has moved in the forward direction beyond the communication position, reaches at least the communication position; The control unit further includes, before starting the label production process, performing a medium remaining determination to determine whether the medium is detected by the medium sensor; If the medium is detected in the remaining medium determination, the reverse transport process is started for the passing wireless tag located at the most downstream position in the forward direction. If the medium is not detected in the remaining medium determination, the reverse conveyance process is not executed, and the label production process is started. The control unit further includes: If the detection state of the medium by the media sensor changes from present to absent during the reverse transport process that was started based on the result of the media remaining determination, a remaining length determination is performed for the medium that was located downstream of the cut position in the forward direction at the start of the reverse transport process that is being executed, by comparing a necessary length that is the length necessary to maintain the hold of the medium by the nip when the passing wireless tag that is the target of the reverse transport process is transported in the reverse direction until it reaches the communication position, with a remaining length that is the length from the cut position to the tip of the medium, which is the end opposite to the storage section side, When it is determined that the remaining length is longer than the required length by the remaining length determination, the reverse conveying process being executed is completed, and then the label producing process is started. When the remaining length determination determines that the remaining length is shorter than the required length, a rescue target calculation process is performed to calculate a rescueable radio tag that is a passing radio tag located further upstream than the passing radio tag located furthest downstream in the forward direction and that can transport the medium in the reverse direction until it reaches the communication position, The control unit further includes: When the salvageable wireless tag is calculated by the salvage target calculation process, the reverse transport process is executed for the salvageable wireless tag, and then the label production process is started. If the rescueable wireless tag is not calculated by the rescue target calculation process, the reverse conveyance process being executed is terminated and the label production process is started. The control unit further includes: In the remaining length determination, a reverse conveyance calculated value calculated based on a conveyance distance by which the medium is conveyed in the reverse direction in the reverse conveyance process being executed and a distance from the medium detection position to the cutting position is used as the remaining length. It is configured as follows.

[0007] The label printer disclosed in this specification can transport the medium in the reverse direction until the passing wireless tag of the label that has moved downstream in the forward direction beyond the communication position to eject the label outside the printer after the label production process has been completed reaches the communication position. Therefore, the label production process can then be performed on the label that has moved in the reverse direction to the communication position. This reduces the waste of labels with wireless tags.

[0008] A control method for realizing the functions of the above-described device, a computer program, and a computer-readable storage medium storing the computer program are also novel and useful. [Effects of the Invention]

[0009] The technology disclosed in this specification realizes a technology that can reduce waste of labels equipped with wireless tags in a label printer. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a block diagram showing the electrical configuration of the label printer according to the embodiment. [Figure 2] FIG. 1 is an explanatory diagram illustrating an outline of the internal configuration of a label printer according to an embodiment. [Figure 3] FIG. 2 is an enlarged view showing a nip formed by a thermal head and a platen roller. [Figure 4] FIG. 10 is a diagram showing a state of the tape according to the first example after a label production process has been performed. [Figure 5] 10A and 10B are diagrams illustrating a state after a reverse feed process has been performed on the tape according to the first example. [Figure 6] FIG. 10 is a diagram showing a state of the tape according to the second example after a label production process has been performed. [Figure 7] FIG. 10 is a diagram showing a state after a reverse feed process has been performed on the tape according to the second example. [Figure 8] 10 is a flowchart showing the procedure of a first printing process according to an embodiment. [Figure 9] 10 is a flowchart showing the procedure of a second printing process according to the embodiment. [Figure 10] 10A and 10B are diagrams showing examples of images formed on a label including an RF tag with which communication is not taking place in the label production process. [Figure 11] 10 is an example of an image displayed on the LCD display when a label including an RF tag with which communication is not being performed is discharged during the label production process. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a label printer embodying the present invention will be described in detail with reference to the accompanying drawings. This embodiment discloses a label printer for printing on a long print medium. The print medium according to this embodiment has a plurality of labels arranged in its lengthwise direction. Furthermore, the labels on the print medium have an RF tag, which is an IC tag related to RFID (Radio Frequency Identification). The RF tag is an example of a wireless tag.

[0012] <Outline of label printer configuration> 1, the label printer 1 of this embodiment is equipped with a controller 10 including a CPU 11 and a memory 12. The label printer 1 also has a user IF 13 (user interface), a communication IF 14 (communication interface), a printing unit 15, and a media sensor 16, which are electrically connected to the controller 10.

[0013] The CPU 11 executes various processes in accordance with programs read from the memory 12 and based on user operations. The controller 10 in Fig. 1 may be configured on a single board, or may be configured by combining multiple boards.

[0014] The memory 12 of the label printer 1 of this embodiment stores various programs, including a control program 21, and various data. The control program 21 is a program that causes the label printer 1 to perform printing operations and input and output various data. The control program 21 includes a program that functions as an operating system. Data stored in the memory 12 includes, for example, label data 22, which is the content to be printed, and remaining length data 23 and reverse feed distance data 24, which are calculated based on the distance the print medium has been transported. The label data 22 is data created by the user or appropriately created by the CPU 11 as the label printer 1 is used. The remaining length data 23 and reverse feed distance data 24 are data appropriately created by the CPU 11 as the label printer 1 is used. For this reason, the label data 22, remaining length data 23, and reverse feed distance data 24 are not stored in the memory 12 when the label printer 1 is shipped from the factory. Details of each data will be described later. The memory 12 is also used as a work area when various processes are executed.

[0015] Note that examples of memory are not limited to ROM, RAM, HDD, etc. built into the label printer 1, but may also be storage media that can be read and written by the CPU 11. For example, external memory such as a USB memory or HDD connected to the label printer 1, and memory or HDD provided in a device connected to the label printer 1 via the communication IF 14 are also examples of memory.

[0016] The user IF 13 has a key group 31 consisting of multiple keys for accepting user operations and a liquid crystal display 32 for displaying images. The user IF 13 may also include a touch panel having a notification function and an operation acceptance function. The user IF 13 may also include another notification means such as an indicator lamp.

[0017] The communication IF 14 includes hardware for communicating with external devices. The communication IF 14 may use a communication standard such as Ethernet (registered trademark), Wi-Fi (registered trademark), or USB. The label printer 1 may be equipped with multiple communication IFs 14. The label printer 1 may be able to communicate with a PC 100 (personal computer) via the communication IFs 14, for example. The label printer 1 may be able to connect to the Internet via the communication IFs 14, and be able to communicate with the PC 100 via the Internet, for example.

[0018] The printing unit 15 has a thermal head 51 that forms an image on the label, a motor 52 that is a drive source for transporting the print medium, an antenna 53 that can communicate with the RF tag on the label, and a cutter 54 that cuts the print medium. The antenna 53 includes hardware for communicating with the RF tag. The label printer 1 can use the antenna 53 to write information to the RF tag on the label and / or read information from the RF tag. The cutter 54 may be installed as an optional unit near the discharge port.

[0019] The medium sensor 16 can detect the presence or absence of a print medium. In this embodiment, the medium sensor 16 is a reflective optical sensor. However, sensors other than reflective optical sensors, such as a transmissive optical sensor, can also be used as the medium sensor 16.

[0020] In this embodiment, the print medium is tape with multiple labels affixed to a release paper. Hereinafter, the direction in which the tape is transported through the label printer 1 is defined as the "length direction," and the direction perpendicular to the length direction is defined as the "width direction." The length of the tape in the width direction is defined as the "tape width." In this embodiment, the tape has a structure in which multiple labels are affixed to a strip of release paper extending in the length direction and aligned in the length direction. While pulling out the built-in roll of tape, the label printer 1 performs a label production process in which the thermal head 51 forms an image on the label and the antenna 53 communicates with the RF tag. In this embodiment, the label after the label production process is sometimes referred to as the product label. Furthermore, the label before the label production process is sometimes referred to as the stock label. The label printer 1 can cut the tape using the cutter 54 to separate the product label after the label production process from the stock label before the label production process. During the label production process, the label printer 1 writes predetermined information to the RF tag through communication between the antenna 53 and the RF tag. A specific example of communication in the label production process may be to write predetermined information to an RF tag, or to read information stored in the RF tag by the antenna 53.

[0021] As shown in Figure 2, the label printer 1 has a cassette housing section 61. A cassette 60 is attached to the cassette housing section 61, and stores a roll Q of tape A wound around a shaft (not shown). The cassette 60 is detachable from the cassette housing section 61. The roll Q stored in the cassette 60 is an example of a roll around which a print medium is wound, and the cassette housing section 61 is an example of a housing section for that roll.

[0022] A platen roller 55 is pressed against the thermal head 51. A nip 6 is formed where the thermal head 51 and the platen roller 55 are pressed against each other. Tape A pulled out from a cassette 60 is sandwiched in the nip 6. The platen roller 55 is driven by a motor 52. The motor 52 rotates the platen roller 55 forward or reverse. When the platen roller 55 rotates forward, it transports the tape A sandwiched in the nip 6 in the forward direction in the length direction. The forward direction is the direction from the cassette 60 to the thermal head 51. On the other hand, when the platen roller 55 rotates reversely, it transports the tape A in the reverse direction in the length direction. The reverse direction is the opposite of the forward direction and is the direction from the thermal head 51 to the cassette 60.

[0023] As shown in Figure 2, the label printer 1 is provided with a communication position 5, a nip 6, a cutting position 7, and a medium detection position 8, in this order from upstream to downstream in the forward direction along the transport path of the tape A pulled out from the cassette 60. The communication position 5 is a position where communication with the RF tag on the label is performed by an antenna 53. The cutting position 7 is a position where the tape A is cut by a cutter 54. The medium detection position 8 is a position where the presence or absence of the tape A is detected by a medium sensor 16.

[0024] The label printer 1 performs a label production process on the label on the tape A while feeding the tape A in the forward direction and pulling it out from the cassette 60. After the label production process, the tape A is fed until the portion of the tape A corresponding to the product label for which the label production process has been performed reaches a position downstream of the cutting position 7 in the forward direction. The label printer 1 then uses the cutter 54 to cut the product label portion of the tape A from the remaining tape A. This allows the user to obtain the portion of the product label that was located at the leading edge Ae of the tape A. The leading edge Ae of the tape A is the downstream end in the forward direction, that is, the end of the tape A opposite the cassette 60. Note that the cutting of the tape A by the cutter 54 is not always performed; it can be performed, for example, in response to settings in the label printer 1, the contents of the print command, or a cutting instruction input by the user to the user IF 13. The label printer 1 of this embodiment can also perform a reverse feed process in which the tape A is fed in the reverse direction opposite to the forward direction. The reverse feed process may be performed before the label production process. The reverse feed process will be described in detail later.

[0025] FIG. 2 shows lengths L1, L3, and m. Length L1 is the minimum length from the leading edge Ae of tape A to communication position 5 that allows nip 6 to maintain the retention of leading edge Ae of tape A. In other words, if tape A of length L1 or greater exists downstream of communication position 5 in the forward direction, nip 6 can retain leading edge Ae of tape A. On the other hand, if tape A of a length shorter than L1 exists downstream of communication position 5 in the forward direction, the leading edge Ae of tape A may not be properly retained by nip 6 and may slip out of nip 6. In this embodiment, length L1 is defined as the required nip maintenance length L1. In this embodiment, the required nip maintenance length L1 is the length along the tape A transport path from communication position 5 to nip 6. Note that nip 6 is created when platen roller 55 comes into contact with and deforms thermal head 51. Therefore, as shown enlarged in FIG. 3, nip 6 has a finite width in the longitudinal direction. FIG. 3 shows a nip width 6a, which is the width of the nip 6 in the longitudinal direction. In this embodiment, as shown in FIG. 3, a nip reference position 6b, which is the position of the nip 6 that serves as the reference for the required nip maintenance length L1, is set to the center of the nip width 6a. Note that the nip reference position 6b may be the downstream end of the nip width 6a in the forward direction. Alternatively, the nip reference position 6b may be the upstream end of the nip width 6a in the forward direction. The nip reference position 6b can be determined, for example, depending on the materials of the thermal head 51 and platen roller 55 that form the nip 6 and the force with which they pinch the tape A. The same applies to the communication position 5 that serves as the reference for the required nip maintenance length L1. In other words, the communication position 5 that serves as the reference for the required nip maintenance length L1 can also be determined taking into account the output of the antenna 53 of the label printer 1, etc.

[0026] Length L3 shown in FIG. 2 is the distance along the transport path of tape A from cutting position 7 to medium detection position 8. In this embodiment, this length L3 is referred to as the cut detection length L3. Length m is the length of tape A from cutting position 7 to the leading edge Ae. Length m is the length of tape A located downstream of cutting position 7 in the forward direction. In other words, length m is the length of tape A that has not been cut by cutter 54 after being transported downstream of cutting position 7 in the forward direction and remains connected to the portion on the cassette 60 side. In this embodiment, this length m is referred to as the remaining length m.

[0027] The nip maintenance length L1, the cut detection length L3, and the remaining length m are all known values ​​in the label printer 1. The nip maintenance length L1 and the cut detection length L3 are known values ​​at the design stage of the label printer 1. The remaining length m can be calculated based on the distance tape A is fed in the forward direction in the label printer 1 during the label production process, etc. Specifically, the CPU 11 of this embodiment calculates the remaining length m by integrating the feed distance tape A is fed in the forward direction after the final cut of tape A is made by cutter 54. This calculated value is a forward feed calculated value calculated from the distance fed in the forward direction. The CPU 11 stores the value of the forward feed calculated value calculated based on the feed distance of tape A in the forward direction as remaining length data 23 in the memory 12. Note that the CPU 11 of this embodiment resets the value of the remaining length data 23 to zero when tape A is cut by cutter 54. Therefore, the CPU 11 of this embodiment can accurately calculate the remaining length m. The CPU 11 may also reset the value of the remaining length data 23 to zero when the label printer 1 is turned on, when the cassette 60 is attached or detached, etc. By resetting the value of the remaining length data 23 when there is a possibility that a change in the remaining length m of the tape A will occur that cannot be grasped by the label printer 1, it is possible to prevent control from being performed based on a value of the remaining length data 23 that differs from the actual remaining length m.

[0028] Furthermore, in the label printer 1, the reverse feed distance, which is the distance the tape A is fed in the reverse direction during the reverse feed process, can also be calculated by accumulating the feed distance of the tape A during the reverse feed process. The CPU 11 of this embodiment then stores the feed distance calculated during the reverse feed process in the memory 12 as reverse feed distance data 24. The CPU 11 of this embodiment creates the reverse feed distance data 24 during the reverse feed process. The value of the created reverse feed distance data 24 may be reset to zero when the reverse feed process starts.

[0029] As shown in FIG. 1, a label creation application 110 with a function for creating label data is stored in a PC 100 connected to the label printer 1. The label creation application 110 is a program for realizing the functions of creating label data and sending a print command to the label printer 1 to print the created label data. In this embodiment, the label data includes data of an image to be printed on a label and data to be stored in the RF tag of the label. Specifically, the label creation application 110 displays an editing screen on the display of the PC 100 for editing the image to be printed on the label and accepts various editing instructions for the image. Furthermore, the label creation application 110 can also display an editing screen on the display of the PC 100 for information to be written to the RF tag and accept various editing instructions. Label data is then created based on the accepted editing instructions.

[0030] The label creation application 110 can transfer the created label data to the label printer 1. The label printer 1 can save the label data transferred from the label creation application 110 in a non-volatile memory area of ​​the memory 12. As a result, label data 22 is stored in the memory 12 of the label printer 1. The label printer 1 can then print labels based on the label data 22 stored in the memory 12. The label creation application 110 can also generate a print command including the created label data and send it to the label printer 1. The print command includes the label data to be printed and setting information for controlling the label printer 1. When the label printer 1 receives a print command sent by the label creation application 110, it can print based on the label data included in the print command.

[0031] <Tape Overview> The label printer 1 of this embodiment can use multiple types of tape A. The multiple types of tape A may differ from one another in at least one of the label size and the position of the RF tag on the label. Specifically, the label printer 1 can use multiple types of tape A with labels that have different lengths in the length direction. Furthermore, the label printer 1 can use multiple types of tape with labels that have RF tags that have different positions in the length direction.

[0032] Figures 4 to 7 show examples of tape A used in the label printer 1. Figures 4 and 5 show a first example of tape A, and Figures 6 and 7 show a second example of tape A. The first and second examples differ in the length of the label along the length of tape A, etc. Figures 4 to 7 show the width direction of tape A aligned with the up-down direction and the length direction of tape A aligned with the left-right direction. The forward direction in Figures 4 to 7 is from right to left.

[0033] The tape A has a plurality of labels C attached to a long release paper B in a line in the length direction. Each of the plurality of labels C has an RF tag D. Figures 4 to 7 show the pitch P and distance L2. The pitch P is a length corresponding to the period of the plurality of labels C that are arranged at equal intervals in the length direction of the tape. The distance L2 is the length from the tip of the label C to the RF tag D. In this embodiment, this distance L2 is referred to as the label tip distance L2. The tip of the label C is the end of the tape A on the tip Ae side.

[0034] In the label printer 1, the pitch P and label leading edge distance L2 of the tape A are known values. For example, with the cassette 60 installed, the label printer 1 can obtain the values ​​of the pitch P and label leading edge distance L2 by sensing the tape A as it is fed forward or backward. Sensing to obtain the pitch P and label leading edge distance L2 can be performed, for example, as an initial operation when the cassette 60 is installed in the label printer 1. The sensing to obtain the pitch P and label leading edge distance L2 can be performed using, for example, the detection values ​​of the media sensor 16. The label printer 1 may be equipped with a sensor other than the media sensor 16 for sensing to obtain the pitch P and label leading edge distance L2. For example, the label printer 1 may be configured to obtain the pitch P and label leading edge distance L2 in response to user input. Specifically, for example, the label printer 1 may be configured to have the user select the type of tape A via the user IF 13 or PC 100 of the label printer 1, and the CPU 11 may obtain the pitch P and label leading edge distance L2 corresponding to the selected type of tape A. The pitch P and label leading edge distance L2 corresponding to the type of tape A may be stored in advance in the memory 12. Alternatively, for example, the label printer 1 may be able to obtain the pitch P and label leading edge distance L2 corresponding to the type of tape A via the Internet.

[0035] <Rescuing labels that have passed the label production position> FIG. 4 shows the communication position 5, nip 6, cutting position 7, and medium detection position 8, and illustrates the state of the tape A after the label production process has been performed on the label C. After the label production process, the tape A is not cut by the cutter 54. The tape A is fed until all of the product labels Cm, which are the labels C for which the label production process has been performed, reach the downstream side of the cutting position 7 in the forward direction. This is to make the product labels Cm easily accessible to the user. All of the labels C upstream of the cutting position 7 in the forward direction are material labels Cn for which the label production process has not yet been performed. If the cutter 54 is set to automatically perform cutting after the label production process, the CPU 11 can perform cutting of the tape A by the cutter 54 in the state shown in FIG. 4.

[0036] FIG. 4 shows multiple material labels Cn. Specifically, the first material label Cn1, second material label Cn2, third material label Cn3, and fourth material label Cn4 are shown in order from downstream in the forward direction. The first material label Cn1 is the material label located at the most downstream in the forward direction. The RF tags D of the first material label Cn1, second material label Cn2, and third material label Cn3 are all located downstream of the communication position 5 in the forward direction. That is, in the example of FIG. 4, the RF tags D of the first material label Cn1, second material label Cn2, and third material label Cn3 are all passing RF tags that have moved forward beyond the communication position 5. For this reason, communication in the label production process has not been performed for the passing RF tags, and communication in the label production process has not been completed. The RF tag D of the first material label Cn1 is the passing RF tag located at the most downstream in the forward direction. On the other hand, the RF tag D of the fourth material label Cn4 is located upstream of the communication position 5 in the forward direction.

[0037] Here, if the next label production process is started in the state shown in Figure 4, the first material label Cn1, second material label Cn2, and third material label Cn3, which have passing RF tags, cannot be included in the label production process. This is because, in a label production process in which tape A is fed in the forward direction, communication with passing RF tags that are already located downstream in the forward direction from communication position 5 is not possible. In other words, if the next label production process is started in the state shown in Figure 4, the fourth material label Cn4 will be the first target of the label production process. Therefore, if the next label production process is started in the state shown in Figure 4, the first material label Cn1, second material label Cn2, and third material label Cn3, which have passing RF tags, will be wasted.

[0038] As described above, in this embodiment, a reverse feed process can be performed to feed the tape A in the reverse direction before the label production process. FIG. 5 shows a state in which a reverse feed process has been performed to feed the tape A in the reverse direction from the state in FIG. 4 until the RF tag D of the first material label Cn1 reaches the communication position 5. In the state in FIG. 5 in which the reverse feed process has been performed for the RF tag D of the first material label Cn1, the first material label Cn1 can be the first target of the next label production process. This is because, in the next label production process, the RF tag D of the first material label Cn1 can communicate with the antenna 53 at the communication position 5. In other words, even if a label C associated with a passed RF tag has once passed the communication position 5 in response to forward transport, it can be rescued as a target of the next label production process by performing a reverse feed process.

[0039] However, reverse feeding from the state shown in FIG. 4 to the state shown in FIG. 5 is possible only when tape A is sufficiently downstream of the RF tag D of the first material label Cn1 in the forward direction. Specifically, for example, if tape A was cut by the cutter 54 in the state shown in FIG. 4, reverse feeding to the state shown in FIG. 5 is not preferable. In the example of tape A shown in FIGS. 4 and 5, the label leading edge length L2 is shorter than the length L1 required to maintain the nip. If tape A were fed in the reverse direction to the position shown in FIG. 5, the leading edge Ae of tape A would slip out of the nip 6. On the other hand, for example, if tape A was not cut by the cutter 54 in the state shown in FIG. 4 and a sufficient remaining length m remains, reverse feeding to the state shown in FIG. 5 is possible. FIG. 4 shows the required length x. The required length x is the length of tape A downstream of the cutting position 7 in the forward direction that is required to maintain the retention of tape A in the nip 6 when tape A is fed in the reverse direction until the passing RF tag located furthest downstream in the forward direction reaches the communication position 5. That is, when the remaining length m is longer than the required length x, the RF tag D of the first material label Cn1 can be conveyed back to the communication position 5 as shown in FIG.

[0040] 6 and 7 show tape A in which the label leading edge length L2 is longer than the nip maintenance length L1, unlike the examples shown in FIGS. 4 and 5. Similar to FIG. 4, FIG. 6 shows a state in which tape A is fed until the product label Cm after the label production process reaches downstream of the cutting position 7 in the forward direction. Similar to FIG. 5, FIG. 7 shows a state in which a reverse feed process is performed from the state shown in FIG. 6, in which the RF tag D of the first material label Cn1 moves to the communication position 5. As shown in FIG. 7, for tape A in which the label leading edge length L2 is longer than the nip maintenance length L1, the RF tag D of the first material label Cn1 can be moved in the reverse direction to the communication position 5 while the leading edge of the first material label Cn1 is held by the nip 6. Therefore, in the state shown in FIG. 7, the RF tag D of the first material label Cn1 can be the first target in the next label production process.

[0041] When labels C associated with passed RF tags are generated, the label printer 1 of this embodiment rescues as many of the labels C associated with the passed RF tags as possible, thereby reducing the amount of labels C that are wasted.

[0042] <Printing process in label printer> Next, we will explain the printing process by the label printer 1. The printing process is executed by the CPU 11 based on processing by the control program 21 in response to receiving a print instruction for label data 22 stored in the label printer 1 via the user IF 13, or receiving a print command from the label creation application 110 via the communication IF 14.

[0043] 8 and 9 each show another aspect of the printing process by the label printer 1. That is, the label printer 1 can execute either a first printing process according to the procedure shown in the flowchart of Fig. 8, or a second printing process according to the procedure shown in the flowchart of Fig. 9. Which printing process to execute is determined based on the settings for the printing process. That is, the CPU 11 starts the first printing process if the setting is to execute the first printing process, and starts the second printing process if the setting is to execute the second printing process.

[0044] <First printing process> 8, in the first printing process, the CPU 11 first determines whether the nip maintenance length L1 is longer than the label leading edge length L2 (S101). If the nip maintenance length L1 is longer than the label leading edge length L2 (S101: YES), the required length x is calculated by subtracting the label leading edge length L2 from the nip maintenance length L1 (S102). On the other hand, if the nip maintenance length L1 is equal to or shorter than the label leading edge length L2 (S101: NO), the required length x is set to "zero" (S103).

[0045] After S102 or S103, the CPU 11 determines whether the value of the count value T is zero (S104). The count value T is "zero" at the start of the first printing process, and thereafter becomes "1" when the leading end of the tape is detected by the media sensor 16. This point will be described later. If the count value T is zero (S104: YES), the value of the remaining length m is set to the forward feed calculated value m1 (S105). The forward feed calculated value m1 is a value calculated based on the feed distance of the tape fed in the forward direction after the final cut of the tape was made by the cutter 54, and is stored in the memory 12 as the remaining length data 23. In other words, the CPU 11 sets the remaining length data 23 read from the memory 12 to the value of the remaining length m. On the other hand, if the count value T is not zero (S104: NO), the value of the remaining length m is set to the reverse feed calculated value m2 (S106). The reverse conveyance calculated value m2 is a value calculated based on the conveyance distance conveyed in the reverse direction during the reverse conveyance process and the distance from the medium sensor 16 to the cutting position 7. The conveyance distance during the reverse conveyance process is stored in the memory 12 as reverse conveyance distance data 24. That is, the CPU 11 calculates the reverse conveyance calculated value m2 by adding the cut detection length L3 to the reverse conveyance distance data 24 read from the memory 12, and sets this value as the value of the remaining length m.

[0046] After S105 or S106, the CPU 11 performs a remaining length determination in which the necessary length x is compared with the remaining length m (S107). That is, as the remaining length determination (S107), the CPU 11 can perform a first remaining length determination using the forward conveyance calculated value m1 as the remaining length m, and a second remaining length determination using the reverse conveyance calculated value m2 as the remaining length m. Then, the value of N is determined based on the result of the remaining length determination. The value of N is a value for determining the material label to be subjected to the label production process. If the remaining length determination finds that the remaining length m is longer than the necessary length x (S107: YES), the value of N is set to "1" (S108). On the other hand, if the remaining length determination finds that the remaining length m is equal to or shorter than the necessary length x (S107: NO), the CPU 11 performs a target calculation process to calculate the value of N (S109). In S109, CPU 11 calculates the value of N using the required nip maintenance length L1, label leading edge distance L2, remaining length m, and label pitch P according to the following formula (1), and sets the value of N to the smallest integer that exceeds the calculated value. {(L1-L2-m) / P}+1 (1)

[0047] After S108 or S109, the CPU 11 determines whether the RF tag of the material label corresponding to the number N from the most downstream in the forward direction is located upstream of the communication position 5 in the forward direction (S110). If the RF tag of the Nth material label is located upstream of the communication position 5 (S110: YES), the CPU 11 starts a label production process for the Nth material label (S111). After that, after the label production process is completed, the CPU 11 resets the count value T to "zero" (S112) and ends the first printing process. Note that the process of resetting the count value T may be performed at the start of the first printing process rather than at the end of the first printing process.

[0048] If the RF tag of the Nth material label is not located upstream of the communication position 5 (S110: NO), reverse feeding processing is started for the RF tag of the Nth material label (S113). That is, feeding of the tape in the reverse direction is started to move the RF tag of the Nth material label (passed RF tag) to the communication position 5. While the reverse feeding processing is being executed (S114: NO), the CPU 11 determines whether the leading edge of the tape has been detected by the media sensor 16 (S115). The leading edge of the tape can be detected based on the change in the detection state of the tape by the media sensor 16 from present to absent. If the leading edge of the tape has not been detected (S115: NO) and feeding of the tape to bring the target RF tag to the communication position 5 is completed (S114: YES), the CPU 11 proceeds to S111 and starts label production processing for the Nth material label.

[0049] On the other hand, if the CPU 11 determines that the leading edge of the tape has been detected based on the detection state of the medium sensor 16 while the reverse feed process is being executed (S114: NO), it sets the count value T to "1" (S116) and proceeds to S104. That is, the CPU 11 sets the remaining length m to the reverse feed calculated value m2 and redoes each of the processes described above as appropriate.

[0050] 8, if the tape can be fed in the reverse direction until the passed RF tag of the material label located at the most downstream position in the forward direction reaches the communication position 5, the remaining length determination determines that the remaining length m is longer than the required length x (S107: YES). Therefore, in this case, the label production process is started after the reverse feeding process is executed for the passed RF tag of the material label located at the most downstream position in the forward direction.

[0051] Furthermore, if the tape cannot be fed in the reverse direction until the passing RF tag of the material label located at the most downstream position in the forward direction reaches the communication position 5, the remaining length determination determines that the remaining length m is shorter than the required length x (S107: NO). In this case, the target calculation process (S109) is performed. The Nth material label calculated in the target calculation process (S109) is the material label located further upstream than the material label located at the most downstream position in the forward direction. If the RF tag of the material label calculated in the target calculation process (S109) is a passing RF tag, then the reverse feed process is performed for that passing RF tag, and then the label production process is started. On the other hand, if the RF tag of the material label calculated in the target calculation process (S109) is not a passing RF tag, then the label production process is started for the material label of the RF tag that is not a passing RF tag. That is, in the first printing process, S109 and S110 perform a salvage target calculation process that calculates salvageable RF tags, which are passing RF tags that are located upstream of the passing RF tag that is located furthest downstream in the forward direction and that can move in the reverse direction until they reach the communication position 5. Furthermore, if a salvageable RF tag is calculated by the salvage target calculation process (S107: NO and S110: NO), a reverse conveyance process is executed for the salvageable RF tag, and then the label production process is started. Furthermore, if a salvageable RF tag is not calculated by the salvage target calculation process (S107: NO and S110: YES), the label production process is started without executing the reverse conveyance process.

[0052] This makes it possible to appropriately determine whether the label material that has moved downstream beyond the communication position 5 in order to discharge the product label from the label printer 1 can be rewound to the communication position 5 and used in the next label production process without wasting it. Therefore, in the label printer 1, when the first printing process is performed intermittently, the number of labels to be discarded can be reduced.

[0053] Furthermore, in the first remaining length determination (S107) when the count value T is "0," the forward feed calculation value m1 is used as the value of the remaining length m. If the leading end of the tape is detected (S115: YES) during the reverse feed process started based on the determination result of the first remaining length determination (S114: NO), the count value T is set to "1" (S116), and the second remaining length determination (S107) is performed. In this second remaining length determination (S107), the reverse feed calculation value m2 is used as the value of the remaining length. As a result, in a situation where the tape has not been cut immediately before and it is estimated that there is a sufficient remaining length m based on the forward feed calculation value m1, the reverse feed process is started first, thereby making it possible to reduce the number of labels to be discarded. Furthermore, when the actual remaining length m can be determined based on the reverse feed calculation value m2 during the reverse feed process, the remaining length determination is started again, thereby reliably preventing the leading end of the tape from coming off the nip 6. Therefore, in the label printer 1, the nip 6 can maintain the tape retention while minimizing the number of labels to be discarded.

[0054] Furthermore, in the calculation process for the items to be repaired, the above formula (1) is used to calculate the number of material labels corresponding to the number N from the most downstream. This makes it possible to minimize the number of material labels to be discarded, even if there are waste material labels.

[0055] <Second printing process> In the second printing process, as shown in FIG. 9, first, the CPU 11 performs a medium remaining determination to determine whether or not a tape has been detected by the medium sensor 16 (S201). If a tape is detected by the medium remaining determination (S201: YES), a reverse feeding process is started for the RF tag of the most downstream material label (S202). The RF tag of the most downstream material label is the passed RF tag located most downstream in the forward direction. While the reverse feeding process that has started is being executed (S203: NO), the CPU 11 determines whether or not the leading edge of the tape has been detected by the medium sensor 16 (S204). If the leading edge of the tape has not been detected (S204: NO) and feeding of the tape to reach the target RF tag to the communication position 5 is completed (S203: YES), the CPU 11 executes a label production process (S205) and ends the second printing process.

[0056] On the other hand, if the CPU 11 determines that the leading edge of the tape has been detected (S204: YES) while the reverse feed process is being performed (S203: NO), it performs a remaining length determination (S206) by comparing the required length x with the remaining length m. The value used as the remaining length m in the second printing process is the reverse feed calculated value m2. This reverse feed calculated value m2 is the actual length of the tape that was located downstream of the cutting position 7 in the forward direction at the start of the reverse feed process being performed. If the remaining length m is longer than the required length x (S206: YES), the reverse feed process that is already being performed continues, and after the reverse feed process is completed (S207), the process proceeds to S205 and the label production process is started.

[0057] If the CPU 11 determines in the remaining length determination that the remaining length m is equal to or shorter than the required length x (S206: NO), it performs a target calculation process to calculate the value of N (S208). In the target calculation process for the second printing process, the CPU 11 also calculates the value of N using the following formula (1) and sets the value of N to the smallest integer greater than the calculated value. Furthermore, the CPU 11 determines whether the RF tags of the material labels corresponding to the number N from the most downstream in the forward direction are located upstream of the communication position 5 in the forward direction (S209). If the RF tag of the Nth material label is already located upstream of the communication position 5 (S209: YES), the CPU 11 proceeds to S205 and starts a label production process for the Nth material label. In other words, since the Nth material label is already located upstream of the communication position 5 in this case, the salvageable RF tag is not calculated. Furthermore, in order to start a label production process for the Nth material label, which is already located upstream of the communication position 5, the CPU 11 ends the reverse conveyance process that is currently being performed.

[0058] If the RF tag of the Nth material label is not located upstream of the communication position 5 (S209: NO), the CPU 11 starts the reverse conveyance process for the RF tag of the Nth material label (S210). That is, if the CPU 11 calculates the RF tag of the Nth material label as a salvageable RF tag, it starts the reverse conveyance process for the salvageable RF tag. If the reverse conveyance process for the RF tag of the Nth material label is completed (S207: YES), the CPU 11 proceeds to S205 and starts the label production process for the Nth material label. That is, even in the second printing process, the CPU 11 performs the salvage target calculation process for calculating the salvageable RF tag in S208 and S209.

[0059] Furthermore, if the CPU 11 does not detect tape in the first remaining medium determination (S201: NO), the CPU 11 proceeds to S205 without performing the reverse transport process, and starts the label production process.

[0060] 9, it is also possible to appropriately determine whether the label material that has moved downstream beyond the communication position 5 in order to eject the product label from the label printer 1 can be rewound to the communication position 5 and used in the next label production process without wasting it. Therefore, in the label printer 1, when the first printing process is performed intermittently, the number of labels to be discarded can be reduced.

[0061] Also, in the second printing process, the rescue target calculation process uses the above formula (1) to calculate the material labels corresponding to the number N from the most downstream. This makes it possible to minimize the number of material labels to be discarded, even if there are waste material labels.

[0062] As described above, the label printer 1 can reduce the number of wasted material labels through the first printing process and the second printing process. However, if some material labels are to be discarded, it is preferable that the CPU 11 distinguish the discarded material labels from product labels. Specifically, for example, if the CPU 11 determines that there is a non-recoverable RF tag among the passing RF tags that does not move in the reverse direction until it reaches the communication position 5 in the reverse conveyance process, the CPU 11 may eject the material label having the non-recoverable RF tag without forming an image on it. That is, the CPU 11 may feed the tape forward until it passes the image formation position of the thermal head 51 in the nip 6 without forming an image on the material label having the non-recoverable RF tag. Note that in the first printing process and the second printing process according to the above-described embodiment, even if a material label having a non-recoverable RF tag is encountered, the label production process (S111 or S205) is performed on the material label upstream of the non-recoverable RF tag in the forward direction. Then, the label production process is performed on the subsequent material label, and the material label having the non-recoverable RF tag is ejected without forming an image on it.

[0063] For example, if the CPU 11 determines that a non-recoverable RF tag is present, the CPU 11 may form an image indicating that the label containing the non-recoverable RF tag includes an RF tag with which communication is not taking place during the label production process. FIG. 10 shows image F1 as an example of an image to be formed on a label containing an RF tag with which communication is not taking place during the label production process. For example, in the label production process (S111 or S205) for a material label subsequent to the label with the non-recoverable RF tag, the CPU 11 may form image F1 using the thermal head 51 on the label with the non-recoverable RF tag that passes through the image forming position. For example, if the CPU 11 determines that a non-recoverable RF tag is present, the CPU 11 may display on the liquid crystal display 32 an image indicating that a label containing an RF tag with which communication is not taking place during the label production process will be discharged. FIG. 11 shows image F2 as an example of an image to be displayed on the liquid crystal display 32 when a label containing an RF tag with which communication is not taking place during the label production process will be discharged. The CPU 11 can display the image F2 on the liquid crystal display 32, for example, in the label production process (S111 or S205) for the material label that follows the label having the non-redeemable RF tag.

[0064] Furthermore, in the first printing process and the second printing process, if the necessary length x and the remaining length m are the same in the remaining length determination, the rescue target calculation process is performed. This reliably prevents the leading edge of the tape from coming out of the nip 6 in the reverse feed process. However, if the necessary length x and the remaining length m are the same in the remaining length determination, the label production process may be started after the reverse feed process for the passing RFID tag located furthest downstream in the forward direction is completed. This further reduces the amount of material labels that are wasted.

[0065] Furthermore, in the reverse feed process, the CPU 11 according to the embodiment described above feeds the tape in the reverse direction until the RF tag of the label that has passed through the reverse feed process reaches at least the communication position 5. However, in the reverse feed process, if the nip maintenance required length L1 of the material label associated with the target passing RF tag is equal to or shorter than the label leading edge length L2, it is preferable to feed the tape in the reverse direction until the leading edge of the material label reaches the image formation position by the thermal head 51. Specifically, in the example shown in FIGS. 6 and 7, in the reverse feed process for the first material label Cn1, it is preferable to feed the tape A in the reverse direction until the RF tag D reaches the communication position 5, and then feed the tape A in the reverse direction until the leading edge of the first material label Cn1 reaches the image formation position of the thermal head 51. By doing so, in the subsequent label production process for the first material label Cn1, an image can be formed from the leading edge of the first material label Cn1. In other words, when label data for forming an image up to the leading edge of the first material label Cn1 is printed, the number of labels to be discarded can be further reduced.

[0066] As explained in detail above, in the label printer 1 of this embodiment, the tape can be fed in the reverse direction until the passing wireless tag of the material label that has moved downstream in the forward direction beyond the communication position 5 in order to discharge the product label out of the machine reaches the communication position 5. Therefore, the label production process can be performed on the material label that has subsequently moved in the reverse direction to the communication position 5. This makes it possible to reduce waste of labels equipped with wireless tags.

[0067] It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Therefore, the present invention can naturally be improved and modified in various ways without departing from the spirit and scope of the present invention. For example, the wireless tag may be an electromagnetic induction type RF tag that communicates by magnetic flux coupling between the antenna coil of the wireless tag and the antenna coil of the reader, or a radio wave type RF tag that communicates by transmitting and receiving radio waves between the antenna of the wireless tag and the antenna of the reader.

[0068] Furthermore, in the embodiment, the label data is created by the label creation application 110 of the PC 100, but the label data may also be created by the label printer 1. Furthermore, in the embodiment, the label data has been described as including both data of the image to be printed on the label and data to be stored in the RF tag of the label. However, the label data may include only data of the image to be printed on the label, and the data to be stored in the RF tag of the label may be treated as data different from the label data.

[0069] In the embodiment, the label printer 1 is described as being capable of executing both the first printing process and the second printing process. However, the label printer 1 may be configured to be compatible with only one of the first printing process or the second printing process. In other words, the CPU 11 may be capable of executing only one of the first printing process or the second printing process, and not the other.

[0070] Also, in the embodiment, an example has been described in which the medium detection position 8 of the medium sensor 16 is located downstream of the cut position 7 in the forward direction. However, the medium detection position of the medium sensor 16 may be located downstream of the nip 6 in the forward direction. In other words, the medium detection position of the medium sensor 16 may be located between the nip 6 and the cut position 7. In this case, the CPU 11 can calculate the reverse conveyance calculated value by subtracting the cut detection length from the cut position 7 to the medium detection position from the reverse conveyance distance data 24.

[0071] Furthermore, in any flowchart disclosed in the embodiments, the execution order of multiple processes in any multiple steps can be arbitrarily changed or can be executed in parallel, as long as no contradiction occurs in the processing content.

[0072] The processes disclosed in the embodiments may be executed by hardware such as a single CPU, multiple CPUs, or ASIC, or a combination thereof. The processes disclosed in the embodiments may be realized in various ways, such as a recording medium on which a program for executing the processes is recorded, or a method. [Explanation of symbols]

[0073] 1 label printer 5. Communication Position 6. Nip 7 Cut position 8 Media detection position 10 Controller 16 Media Sensor 51 Thermal head 52 Transport motor 53 Antenna 54 Cutter 55 Platen roller 61 Cassette storage section A tape B Release paper C Label D. RF tag

Claims

1. a storage unit that stores a roll of a medium, the medium having a long release paper and a plurality of labels attached to the release paper, the labels having wireless tags; a thermal head for forming an image on the label of the medium; a platen roller that forms a nip between itself and the thermal head, and when rotating forward, conveys the medium sandwiched in the nip in a forward direction from the storage unit to the thermal head, and when rotating reverse, conveys the medium sandwiched in the nip in a reverse direction from the thermal head to the storage unit; a motor capable of rotating the platen roller in the forward direction or the reverse direction; an antenna capable of communicating with the wireless tag at a communication position upstream of the nip in the forward direction; a cutter that cuts the medium at a cutting position downstream of the nip in the forward direction; a control unit, The control unit a label production process in which, while the medium is being transported in the forward direction, the thermal head forms an image on the label and the antenna communicates with the wireless tag; a reverse transport process of transporting the medium in the reverse direction until a passing wireless tag, which is the wireless tag that has moved in the forward direction beyond the communication position, reaches at least the communication position; The control unit further includes, before starting the label production process, For the medium downstream of the cutting position in the forward direction, a remaining length determination is performed by comparing a necessary length, which is a length necessary to maintain the medium held by the nip when the passing wireless tag located furthest downstream in the forward direction is transported in the reverse direction until it reaches the communication position, with a remaining length, which is the length from the cutting position to the tip of the medium, which is the end opposite to the storage section side; When it is determined that the remaining length is longer than the required length by the remaining length determination, the reverse conveyance process is performed for the passing RFID tag located at the most downstream position in the forward direction, and then the label production process is started. When the remaining length determination determines that the remaining length is shorter than the required length, a rescue target calculation process is performed to calculate rescueable radio tags that are passing radio tags located further upstream than the passing radio tag located furthest downstream in the forward direction and that can move in the reverse direction until they reach the communication position, The control unit further includes: When the salvageable wireless tag is calculated by the salvage target calculation process, the reverse transport process is executed for the salvageable wireless tag, and then the label production process is started. If the rescueable wireless tag is not calculated by the rescue target calculation process, the reverse conveyance process is not executed and the label production process is started. A label printer configured to:

2. 2. The label printer according to claim 1, The control unit In the remaining length determination, a forward conveyance calculated value calculated based on a conveyance distance by which the medium is conveyed in the forward direction after the final cutting of the medium by the cutter is used as the remaining length. A label printer configured to:

3. 3. The label printer according to claim 2, a storage unit that stores the remaining length; The control unit When the medium is cut by the cutter while the remaining length is stored in the storage unit, the remaining length stored in the storage unit is set to zero. A label printer configured to:

4. 3. The label printer according to claim 2, a medium sensor capable of detecting the presence or absence of the medium at a medium detection position downstream of the nip in the forward direction; The control unit The remaining length determination is a first remaining length determination that is performed using the forward conveyance calculated value as the remaining length; a second remaining length determination that is performed using a reverse conveyance calculated value calculated based on a conveyance distance by which the medium is conveyed in the reverse direction in the reverse conveyance process that is being executed and a distance from the medium detection position to the cutting position, as the remaining length; The control unit further If the detection state of the medium by the medium sensor changes from "present" to "absent" during the reverse transport process that was started based on the determination result of the first remaining length determination, the second remaining length determination is performed. A label printer configured to:

5. a storage unit that stores a roll of a medium, the medium having a long release paper and a plurality of labels attached to the release paper, the labels having wireless tags; a thermal head for forming an image on the label of the medium; a platen roller that forms a nip between itself and the thermal head, and when rotating forward, conveys the medium sandwiched in the nip in a forward direction from the storage unit to the thermal head, and when rotating reverse, conveys the medium sandwiched in the nip in a reverse direction from the thermal head to the storage unit; a motor capable of rotating the platen roller in the forward direction or the reverse direction; an antenna capable of communicating with the wireless tag at a communication position upstream of the nip in the forward direction; a cutter that cuts the medium at a cutting position downstream of the nip in the forward direction; a medium sensor capable of detecting the presence or absence of the medium at a medium detection position downstream of the nip in the forward direction; a control unit, The control unit a label production process in which, while the medium is being transported in the forward direction, the thermal head forms an image on the label and the antenna communicates with the wireless tag; a reverse transport process of transporting the medium in the reverse direction until a passing wireless tag, which is the wireless tag that has moved in the forward direction beyond the communication position, reaches at least the communication position; The control unit further includes, before starting the label production process, performing a medium remaining determination to determine whether the medium is detected by the medium sensor; If the medium is detected in the remaining medium determination, the reverse transport process is started for the passing wireless tag located at the most downstream position in the forward direction. If the medium is not detected in the remaining medium determination, the reverse conveyance process is not executed, and the label production process is started. The control unit further includes: If the detection state of the medium by the media sensor changes from present to absent during the reverse transport process that was started based on the result of the media remaining determination, a remaining length determination is performed for the medium that was located downstream of the cut position in the forward direction at the start of the reverse transport process that is being executed, by comparing a necessary length that is the length necessary to maintain the hold of the medium by the nip when the passing wireless tag that is the target of the reverse transport process is transported in the reverse direction until it reaches the communication position, with a remaining length that is the length from the cut position to the tip of the medium, which is the end opposite to the storage section side, When it is determined that the remaining length is longer than the required length by the remaining length determination, the reverse conveying process being executed is completed, and then the label producing process is started. When the remaining length determination determines that the remaining length is shorter than the required length, a rescue target calculation process is performed to calculate a rescueable radio tag that is a passing radio tag located further upstream than the passing radio tag located furthest downstream in the forward direction and that can transport the medium in the reverse direction until it reaches the communication position, The control unit further includes: When the salvageable wireless tag is calculated by the salvage target calculation process, the reverse transport process is executed for the salvageable wireless tag, and then the label production process is started. If the rescueable wireless tag is not calculated by the rescue target calculation process, the reverse conveyance process being executed is terminated and the label production process is started. The control unit further includes: In the remaining length determination, a reverse conveyance calculated value calculated based on a conveyance distance by which the medium is conveyed in the reverse direction in the reverse conveyance process being executed and a distance from the medium detection position to the cutting position is used as the remaining length. A label printer configured to:

6. 10. The label printer according to claim 1, wherein: The control unit In the relief target calculation process, a nip maintenance required length L1, which is the minimum length from the leading edge of the medium to the communication position that allows the leading edge side of the medium to be held by the nip; a distance L2 from the label tip, which is the end of the label on the tip side of the medium, to the wireless tag; The remaining length m; a pitch P of the plurality of labels provided on the medium; The number N of the labels from the leading end side of the medium is set to the smallest integer greater than the value calculated by the following formula (1), {(L1-L2-m) / P}+1...(1) If the wireless tag of the label corresponding to the number N of sheets from the leading end side of the medium is the passing wireless tag, the passing wireless tag is determined to be the recoverable wireless tag. A label printer configured to:

7. A label printer according to any one of claims 1 to 5, The control unit If there is a non-recoverable radio tag among the passing radio tags that does not move in the reverse direction until it reaches the communication position in the reverse transport process, the medium is transported in the forward direction until it passes an image formation position by the thermal head without forming an image on the label having the non-recoverable radio tag. A label printer configured to:

8. A label printer according to any one of claims 1 to 5, The control unit If there is a non-recoverable radio tag among the passing radio tags that does not move in the reverse direction until it reaches the communication position in the reverse transport process, an image is formed on the label having the non-recoverable radio tag, indicating that the label includes the radio tag with which communication has not been performed in the label production process. A label printer configured to:

9. A label printer according to any one of claims 1 to 5, The control unit In the reverse conveying process, if the distance from the label tip, which is the end portion on the leading edge side of the medium, to the wireless tag is longer than a necessary nip maintenance length, which is the minimum length from the leading edge of the medium to the communication position, that allows the nip to maintain the holding of the leading edge side of the medium, the medium is conveyed in the reverse direction until the leading edge of the label reaches an image formation position by the thermal head. A label printer configured to:

Images