Printer device

Abstract

The present invention discloses a printer device that can reliably detect the presence of a label even when the printed label is in a position irradiated by external light. The printer device includes: a light irradiation unit that irradiates light on an area irradiated by external light where a printed label exists; a light irradiation control unit that switches between irradiation and non-irradiation of light by the light irradiation unit; a light receiving unit that, in synchronization with the switching of light irradiation and non-irradiation by the light irradiation control unit, obtains an optical signal from the area where a printed label exists; and a label presence / absence determination unit that determines the presence or absence of a label based on a first signal obtained by the light receiving unit when the light irradiation unit does not irradiate light and a second signal obtained by the light receiving unit when the light irradiation unit irradiates light.

Description

[0001] This application claims priority from a Japanese application with an application date of November 17, 2021 and an application number of JP2021-187077, incorporates the content of the above application by reference, and incorporates the entire disclosure herein by reference. Technical Field

[0002] Embodiments of the present invention relate to a printer device. Background Art

[0003] A printer device that prints on label paper discharges labels that are separated from the peeling paper by a peeling unit. In addition, a peeling sensor for detecting the presence or absence of a printed label may be provided on a holding member that holds the discharged label. The peeling sensor is configured as an inexpensive optical sensor and is provided outside the housing of the label printer together with the holding member that holds the discharged label.

[0004] In such a printer device, since the peeling sensor is easily affected by external light, there is a possibility of erroneously detecting the presence or absence of a label. Summary of the Invention

[0005] In view of the above problems, the problem to be solved by the present invention is to provide a printer device that can reliably detect the presence of a printed label even when the printed label is in a position irradiated by external light.

[0006] To solve the above problems, a printer device according to an embodiment of the present invention includes a light irradiation unit, a light irradiation control unit, a light receiving unit, and a label presence / absence determination unit. The light irradiation unit irradiates light on an area irradiated by external light where a printed label exists. The light irradiation control unit switches between irradiating and not irradiating light by the light irradiation unit. The light receiving unit synchronizes with the switching of irradiating and not irradiating light by the light irradiation control unit and obtains a light signal from an area where a printed label exists. The label presence / absence determination unit determines the presence or absence of a label based on a first signal obtained by the light receiving unit when the light irradiation unit does not irradiate light and a second signal obtained by the light receiving unit when the light irradiation unit irradiates light.

[0007] According to the above printer device, the presence of a printed label can be reliably detected even when the printed label is in a position irradiated by external light.

[0008] In the above printer device, the light irradiation unit and the light receiving unit are provided on the same side of the label surface of the printed label.

[0009] According to the above printer device, the light irradiation unit and the light receiving unit can be arranged in a smaller space.

[0010] In the above-described printer device, the light irradiation unit and the light receiving unit are provided at positions opposite to each other across the label surface of the printed label.

[0011] According to the above-described printer device, since the amount of external light incident on the light receiving unit decreases, the influence of external light can be reduced.

[0012] In the above-described printer device, the label presence / absence determination unit determines the presence or absence of the label based on the magnitude relationship between the difference between the level of the first signal and the level of the second signal and a threshold value.

[0013] According to the above-described printer device, the presence or absence of a label can be detected through simple signal processing.

[0014] In the above-described printer device, the label presence / absence determination unit sets the threshold value based on the level of the first signal.

[0015] According to the above-described printer device, even when the intensity of external light changes, the presence or absence of a label can be reliably detected.

[0016] In the above-described printer device, it further includes: a print control unit that temporarily stops the printing of the next label on the condition that the label presence / absence determination unit determines that there is a label, and starts the printing of the next label on the condition that the label presence / absence determination unit determines that there is no label.

[0017] According to the above-described printer device, it is possible to prevent the retention of printed labels.

[0018] In the above-described printer device, the label presence / absence determination unit has a threshold setting list in which the threshold value decreases as external light increases, and sets the threshold value based on the level of the first signal and the threshold setting list.

[0019] According to the above-described printer device, the threshold value can be decreased as external light increases, making it easy to set the threshold value.

[0020] In the above-described printer device, the label presence / absence determination unit sets the threshold value at the start of printing.

[0021] According to the above-described printer device, a threshold value corresponding to the external light when printing is performed by the printer can be set.

[0022] In the above-described printer device, the label presence / absence determination unit calculates the difference based on the average value of the first signal during the period when the light irradiation unit does not irradiate light and the average value of the second signal during the period when the light irradiation unit irradiates light.

[0023] According to the above-described printer device, the influence caused by the flicker of external light can be reduced. Description of the Drawings

[0024] Figure 1 It is a diagram showing an example of the schematic configuration of the label printer according to the first embodiment.

[0025] Figure 2 It is a diagram for explaining the structure and operating principle of the peeling sensor included in the label printer according to the first embodiment.

[0026] Figure 3 It is a diagram showing an example of the signal output detected by the peeling sensor under external light.

[0027] Figure 4 It is a functional block diagram showing an example of the functional configuration of the label printer.

[0028] Figure 5 It is a flowchart showing an example of the process flow of the printing operation of the label printer according to the first embodiment.

[0029] Figure 6 It is shown in Figure 5 The flowchart is a flowchart showing an example of the process for determining the presence or absence of a label.

[0030] Figure 7 It is a diagram for explaining a method of setting a threshold value for determining the presence or absence of a label according to the intensity of external light.

[0031] Figure 8 It is a cross-sectional view showing an example of the internal structure of the label printer according to the second embodiment.

[0032] Figure 9 It is a diagram for explaining the structure and operating principle of the label sensor included in the label printer according to the second embodiment.

[0033] Figure 10 It is a diagram showing an example of the signal output detected by the label sensor under external light.

[0034] Figure 11 It is a flowchart showing an example of the process flow of the printing operation of the label printer according to the second embodiment.

[0035] Explanation of reference numerals

[0036] 10, 40 Label printer (printer device) 11 Housing 12 Label reel

[0037] 13 Label paper 14 Label 15 Peeling paper 16 Thermal print head

[0038] 17 Paper feed roller 18 Driving motor 19 Peeling bar 20 Peeling roller

[0039] 21, 36 discharge ports 22 holding member 23 peeling sensor

[0040] 24 label sensor 26 label paper (label) without liner, 27 paper feed die

[0041] 28 cutter 29 fixed blade 30 movable blade

[0042] 31 light emitting element (LED) 32 emitted light 33 reflected light

[0043] 34 light receiving element 35 gap 38 external light 41 light irradiation section

[0044] 42 light irradiation control section 43 light receiving section 44 label presence / absence determination section

[0045] 45 printing control section

[0046] Ca, Cb, Cc, Cd, Ce, Cf, Cg, Ch, Ci, Cj sensor output examples

[0047] pa lighting period pb extinguishing period

[0048] Sa, Sb, Sc, Sd, Se, Sf, Sg, Sh, Si, Sj detection states

[0049] T threshold setting list Th, Th(V) threshold V sensor output (first signal, second signal) ΔV difference Detailed implementation mode

[0050] (First embodiment)

[0051] The following refers to the drawings to detail the first embodiment of the label printer according to the embodiments of the present invention.

[0052] (Overall configuration of the label printer)

[0053] Use Figure 1 To illustrate the schematic configuration of the label printer 10 according to the first embodiment. Figure 1 It is a diagram showing an example of the schematic configuration of the label printer according to the first embodiment. In addition, the label printer 10 is an example of the printer device of the present disclosure.

[0054] The label printer 10 includes a label reel 12 that winds a label paper 13, which is an example of a printing paper, into a roll shape inside a housing 11. In addition, the label printer 10 pulls out the label paper 13 from the label reel 12 while performing printing.

[0055] The label paper 13 is wound into a roll with the label 14 adhered to the release paper 15. The label paper 13 pulled out from the label roll 12 is conveyed toward the discharge port 21 while being clamped between the paper feed roller 17 and the thermal print head 16. At this time, the label 14 serving as the printing surface is located on the side of the thermal print head 16. In addition, the paper feed roller 17 is rotationally driven by a drive motor 18 such as a stepping motor.

[0056] The thermal print head 16 has a structure in which a plurality of heating elements are arranged in a row, and printing is performed on the label 14 clamped between the thermal print head 16 and the paper feed roller 17 by heating the heating elements corresponding to the printing pattern. In addition, the label printer 10 may also be a type that performs printing by clamping an ink ribbon (not shown) between the thermal print head 16 and the label 14 and transferring the ink of the ink ribbon heated by the thermal print head 16 to the label 14.

[0057] On the back side of the label 14 is an adhesive layer, and the label 14 is adhered to the release paper 15 through this adhesive layer. The printed label paper 13 is separated into the label 14 and the release paper 15 by the release lever 19. The release lever 19 is a V-shaped columnar member having two surfaces intersecting at an acute angle. The release lever 19 is provided along the Y axis. Before the start of printing, the release paper 15 folds back downward (negative Z-axis side) at the intersection of the two surfaces of the release lever 19 and becomes a state of being clamped between the paper feed roller 17 and the release roller 20. Therefore, when the paper feed roller 17 rotates and the label 14 is printed, the release paper 15 is conveyed in the negative Z-axis direction while being clamped between the paper feed roller 17 and the release roller 20. Then, the label 14 adhered to the release paper 15 is separated from the release paper 15 at the intersection of the two surfaces of the release lever 19.

[0058] The label 14 separated from the release paper 15 is discharged from the discharge port 21 and stays at a position above the holding member 22.

[0059] Inside the holding member 22, a release sensor 23 for detecting the presence or absence of the label 14 is provided. The release sensor 23 detects whether there is a label 14 peeled off from the label paper 13 above the holding member 22. When the release sensor 23 detects the label 14, the label printer 10 temporarily stops the conveyance and printing of the label paper 13. Then, when the user removes the printed label 14 from above the holding member 22, the release sensor 23 detects the absence of the label 14 and resumes the conveyance and printing of the label paper 13. In addition, the structure and operation principle of the release sensor 23 will be described later.

[0060] (Structure and operation principle of the release sensor)

[0061] Use Figure 2 and Figure 3, the structure and operation principle of the peeling sensor 23 will be described. Figure 2 This is a diagram illustrating the structure and operation principle of the peeling sensor included in the label printer according to the first embodiment. Figure 3 This is a diagram showing an example of the signal output detected by the peeling sensor under external light.

[0062] The peeling sensor 23 includes a light-emitting element 31 and a light-receiving element 34. The light-emitting element 31 irradiates light at a predetermined cycle by the action of a drive circuit (not shown). The light-emitting element 31 is, for example, an LED (Light Emitting Diode). Hereinafter, the light-emitting element 31 will also be referred to as LED31. In addition, although the wavelength of the light irradiated by the light-emitting element 31 is not limited, near-infrared light, which is invisible light, is expected to be used. Further, it is expected that the light-receiving element 34 has high sensitivity to light of the same wavelength as the light irradiated by the light-emitting element 31. Therefore, a filter that transmits light of the wavelength irradiated by the light-emitting element 31 may be provided on the surface of the light-receiving element 34.

[0063] The light-receiving element 34 outputs an electrical signal corresponding to the amount of received light in synchronization with the time when the light-emitting element 31 irradiates light. The light-receiving element 34 is, for example, a photodiode. Thus, the peeling sensor 23 is a reflection-type sensor in which the light-receiving element 34 detects the reflected light of the light irradiated by the light-emitting element 31.

[0064] The light-emitting element 31 irradiates light upward from the gap 35 of the paper feed die 27 formed on the upper part of the holding member 22 to the upper side of the holding member 22. The light-receiving element 34 detects the reflected light from the label 14 placed inside the gap 35 (on the positive Z-axis side). In addition, the gap 35 is a gap formed by cutting a part of the paper feed die 27 along the direction in which the label 14 is discharged, that is, the X-axis.

[0065] Figure 2 The detection state Sa shown indicates a situation where the emitted light 32 irradiated by the LED31 is reflected by the label 14 and the reflected light 33 is detected by the light-receiving element 34.

[0066] At this time, as shown in the detection state Sb, the emitted light 32 irradiated by the LED31 is reflected by the back surface (adhesive layer) of the label 14 after passing through the gap 35. Thereafter, the reflected light 33 is detected by the light-receiving element 34.

[0067] On the other hand, when there is no label 14 above the paper feed die 27, as shown in Figure 2 the detection state Sc, the emitted light 32 irradiated by the LED31 passes through the gap 35 and then passes through above the paper feed die 27 (on the positive Z-axis side). Therefore, the light-receiving element 34 does not detect the emitted light 32 irradiated by the LED31.

[0068] Next, use Figure 3 to explain the signal output detected by the peeling sensor 23 under the external light 38.

[0069] The paper conveying die 27 is arranged at a position facing the outside of the housing 11 so as to easily take out the printed label 14. Therefore, the external light 38 in the environment where the label printer 10 is arranged is irradiated on the printing surface of the printed label 14. The external light 38 includes indoor lighting such as fluorescent lamps, incandescent bulbs, and LED lighting, and sunlight. Such external light 38 sometimes has an adverse effect when the peeling sensor 23 detects the presence or absence of the label 14.

[0070] Figure 3 The shown detection state Sd indicates a situation where the external light 38 is irradiated on the printing surface of the label 14 in the state where the printed label 14 is on the paper conveying die 27.

[0071] In the detection state Sd, the emitted light 32 from the LED 31 is reflected by the back surface (adhesive layer) of the label 14 to generate the reflected light 33. Then, the light receiving element 34 detects the reflected light 33. At this time, when the external light 38 is irradiated on the surface of the label 14, according to the intensity of the external light 38 and the transmittance of the label 14, a part of the external light 38 passes through the label 14 and reaches the light receiving element 34 together with the reflected light 33. Therefore, in the detection state Sd, the light receiving element 34 outputs a sensor output V larger than the case without the external light 38 regardless of whether the LED 31 irradiates the emitted light 32 or not.

[0072] Thereafter, the sensor output V obtained when the LED 31 irradiates the emitted light 32 is only larger than the sensor output V obtained when the LED 31 does not irradiate the emitted light 32 by an amount corresponding to the magnitude of the reflected light 33. Therefore, regardless of the intensity of the external light 38, when the difference between the sensor output V obtained when the LED 31 irradiates the emitted light 32 and the sensor output V obtained when the LED 31 does not irradiate the emitted light 32 by the peeling sensor 23 is greater than or equal to a preset threshold value, it can be determined that there is a label 14.

[0073] Figure 3 The shown detection state Se indicates a situation where the external light 38 is irradiated in the state where there is no label 14 on the paper conveying die 27.

[0074] In the detection state Se, the emitted light 32 from the LED 31 passes through the gap 35 of the paper conveying die 27 (refer to Figure 2) and is radiated into space. Therefore, the light-receiving element 34 cannot detect the reflected light generated by the outgoing light 32. At this time, when external light 38 is irradiated on the surface of the paper conveyance die 27, the external light 38 passes through the gap 35 and reaches the light-receiving element 34. Therefore, the light-receiving element 34 outputs a sensor output V corresponding to the intensity of the external light 38. In addition, this state is independent of the emission state of the outgoing light 32 based on the LED 31. Therefore, in the detection state Se, there is almost no difference between the sensor output V obtained when the LED 31 irradiates the outgoing light 32 and the sensor output V obtained when the LED 31 does not irradiate the outgoing light 32. Therefore, regardless of the intensity of the external light 38, when the difference between the sensor output V obtained when the LED 31 irradiates the outgoing light 32 and the sensor output V obtained when the LED 31 is in a state where it does not irradiate the outgoing light 32 is less than a preset threshold value, it can be determined that there is no label 14.

[0075] Hereinafter, a method for determining the presence or absence of the label 14 will be described based on the waveform of the actual sensor output V. Figure 3 The sensor output example Ca shown represents an example of the sensor output V in a state where there is a label 14 on the paper conveyance die 27 and there is no external light 38.

[0076] The LED 31 repeatedly switches between the lit state and the extinguished state at a preset time. In the case of the sensor output example Ca, the LED 31 is lit from time ta to time tb and from time tc to time td. On the other hand, the LED 31 is extinguished before time ta, from time tb to time tc, and after time td. The period during which the LED 31 is lit is defined as the lit period pa, and the period during which the LED 31 is extinguished is defined as the extinguished period pb. The lengths of the lit period pa and the extinguished period pb can be set arbitrarily. In addition, the ratio (duty ratio) of the lit period pa and the extinguished period pb is not limited.

[0077] At this time, the sensor output V output by the light-receiving element 34 has a pulse waveform as shown in the sensor output example Ca. That is, during the extinguished period pd of the LED 31, a very small sensor output V is obtained. Thereafter, during the lit period pa, a sensor output V corresponding to the outgoing light 32 of the LED 31 is obtained. Then, a difference ΔV is generated between the sensor output V during the lit period pa and the sensor output V during the extinguished period pb.

[0078] In addition, here, it is explained that the sensor output V is generated according to positive logic, that is, the more light the light-receiving element 34 receives, the larger the sensor output V output. In addition, the sensor output V can also be generated according to negative logic. That is, it can be that the more light the light-receiving element 34 receives, the smaller the sensor output V output.

[0079] Regarding this, Figure 3The sensor output example Cb shown represents an example of the sensor output V in a state where there is no label 14 on the paper conveyance die 27 and there is no external light 38. The lighting and extinguishing times of the LED 31 in the sensor output example Cb are the same as those described in the sensor output example Ca.

[0080] At this time, the sensor output V output by the light receiving element 34 is almost equal regardless of the lighting state or extinguishing state of the LED 31, as shown in the sensor output example Cb. That is, the difference ΔV between the sensor output V during the lighting period pa and the sensor output V during the extinguishing period pb is a very small value.

[0081] From the comparison between the sensor output example Ca and the sensor output example Cb, it can be seen that in the absence of external light 38, when comparing the difference ΔV between the sensor output V during the lighting period pa and the sensor output V during the extinguishing period pb with a threshold value, if the difference ΔV is greater than or equal to the threshold value, it can be determined that the label 14 exists. In addition, it can be seen that if the difference ΔV is less than the threshold value, it can be determined that the label 14 does not exist.

[0082] Figure 3 The sensor output example Cc shown represents an example of the sensor output V in a state where there is a label 14 on the paper conveyance die 27 and there is external light 38. The lighting and extinguishing times of the LED 31 in the sensor output example Cc are the same as those described in the sensor output example Ca.

[0083] At this time, the sensor output V output by the light receiving element 34 has a pulse waveform as shown in the sensor output example Cc. That is, a relatively small sensor output V is obtained during the extinguishing period pb of the LED 31. In addition, the sensor output V obtained during the extinguishing period pb of the LED 31 is only larger by the value corresponding to the portion where the external light 38 transmitted through the label 14 reaches the light receiving element 34 compared to the sensor output V obtained at the same time in the sensor output example Ca. Then, the sensor output V obtained during the lighting period pa is larger than the sensor output V obtained during the extinguishing period pb. Then, a difference ΔV is generated between the sensor output V during the lighting period pa and the sensor output V during the extinguishing period pb.

[0084] Regarding this, Figure 3 The sensor output example Cd shown represents an example of the sensor output V in a state where there is no label 14 on the paper conveyance die 27 and there is external light 38. The lighting and extinguishing times of the LED 31 in the sensor output example Cd are the same as those described in the sensor output example Ca.

[0085] At this time, the sensor output V output by the light-receiving element 34 is, as shown in the sensor output example Cd, almost the same value corresponding to the intensity of the external light 38 regardless of whether the LED 31 is lit or off. That is, the difference ΔV between the sensor output V during the lighting period pa and the sensor output V during the non-lighting period pb is a very small value.

[0086] From the comparison between the sensor output example Cc and the sensor output example Cd, it can be seen that in the presence of the external light 38, the difference ΔV between the sensor output V during the lighting period pa and the sensor output V during the non-lighting period pb is compared with a threshold value. When the difference ΔV is greater than or equal to the threshold value, it can be determined that the tag 14 exists. In addition, it can be seen that when the difference ΔV is less than the threshold value, it can be determined that the tag 14 does not exist.

[0087] It can be seen that, that is, regardless of the presence or absence of the external light 38, the difference ΔV between the sensor output V during the lighting period pa and the sensor output V during the non-lighting period pb is compared with a threshold value. When the difference ΔV is greater than or equal to the threshold value, it can be determined that the tag 14 exists. In addition, it can be seen that when the difference ΔV is less than the threshold value, it can be determined that the tag 14 does not exist.

[0088] (Functional configuration of the label printer)

[0089] Use Figure 4 to describe the functional configuration of the label printer 10. Figure 4 is a functional block diagram showing an example of the functional configuration of the label printer.

[0090] The control unit (not shown) included in the label printer 10 has the configuration of a computer and operates by executing the control program stored in the control unit. As Figure 4 shown, the control unit implements the light irradiation unit 41, the light irradiation control unit 42, the light receiving unit 43, the tag presence determination unit 44, and the printing control unit 45 as functional units.

[0091] The light irradiation unit 41 irradiates the area irradiated by the external light 38 where the printed label 14 exists with light from the light emitting element 31.

[0092] The light irradiation control unit 42 switches between irradiation and non-irradiation of light by the light irradiation unit 41.

[0093] The light receiving unit 43 synchronizes with the switching of light irradiation and non-irradiation by the light irradiation control unit 42 to obtain a light signal from the area where the printed label 14 exists with the light receiving element 34.

[0094] The label presence / absence determination unit 44 determines the presence or absence of the label 14 based on the sensor output V (first signal) obtained by the light receiving unit 43 when the light irradiation unit 41 does not irradiate light and the sensor output V (second signal) obtained by the light receiving unit 43 when the light irradiation unit 41 irradiates light.

[0095] The print control unit 45 acquires the print content and an instruction to start printing, and instructs each unit of the label printer 10 to start printing. In addition, the print control unit 45 temporarily stops the printing of the next label on the condition that the label presence / absence determination unit 44 determines that there is a label 14. In addition, the print control unit 45 instructs each unit of the label printer 10 to start printing the next label on the condition that the label presence / absence determination unit 44 determines that there is no label 14. Further, the print control unit 45 determines whether a specified number of labels 14 have been printed.

[0096] (Flow of the printing operation performed by the label printer)

[0097] Use Figure 5 and Figure 6 to describe the flow of the printing process performed by the label printer 10. Figure 5 FIG. is a flowchart showing an example of the flow of the printing operation of the label printer according to the first embodiment. Figure 6 It shows Figure 5 a flowchart showing an example of the flow of the process for determining the presence or absence of a label in the flowchart.

[0098] The print control unit 45 instructs each unit of the label printer 10 to start printing (step S11).

[0099] The label presence / absence determination unit 44 performs a label presence / absence determination process for determining the presence or absence of the label 14 (step S12). When it is determined that there is a label 14, the process proceeds to step S13. On the other hand, when it is not determined that there is a label 14, the process proceeds to step S14. In addition, the detailed flow of the label presence / absence determination process will be described later (see Figure 6 ).

[0100] In step S12, when it is determined that there is a label 14, the print control unit 45 temporarily stops the printing operation (step S13). Thereafter, the process returns to step S12, and the label presence / absence determination process is repeated.

[0101] When it is determined in step S12 that there is no label 14, that is, when the label 14 for which it is determined that printing has been completed is removed from the holding member 22, the print control unit 45 determines whether a specified number of labels 14 have been printed (step S14). When it is determined that a specified number of labels 14 have been printed (step S14: Yes), the label printer 10 ends Figure 5Processing. On the other hand, when it is not determined that the specified number of labels 14 have been printed (step S14: No), the process proceeds to step S15.

[0102] In step S14, when it is not determined that the specified number of labels 14 have been printed, the print control unit 45 resumes printing (step S15).

[0103] The print control unit 45 increments the number of printed labels 14 (step S16). Thereafter, the process returns to step S12.

[0104] Next, use Figure 6 to explain the process of the label presence / absence determination process.

[0105] First, for the light irradiation unit 41, the light irradiation control unit 42 turns off the LED 31 (step S21).

[0106] The light receiving unit 43 detects the sensor output V (first signal) of the light receiving element 34 (step S22).

[0107] For the light irradiation unit 41, the light irradiation control unit 42 turns on the LED 31 (step S23).

[0108] The light receiving unit 43 detects the sensor output V (second signal) of the light receiving element 34 (step S24).

[0109] The label presence / absence determination unit 44 calculates the difference ΔV between the second signal and the first signal (step S25).

[0110] The label presence / absence determination unit 44 determines whether the difference ΔV is greater than or equal to the threshold Th of the difference (step S26). When it is determined that the difference ΔV is greater than or equal to the threshold Th (step S26: Yes), the process proceeds to step S27. On the other hand, when it is not determined that the difference ΔV is greater than or equal to the threshold Th (step S26: No), the process proceeds to step S28.

[0111] In step S26, when it is determined that the difference ΔV is greater than or equal to the threshold Th, the label presence / absence determination unit 44 determines that there is a label 14 on the holding member 22 (paper conveyance die 27) (step S27). Thereafter, the process returns to the main program ( Figure 5 ).

[0112] In step S26, when it is determined that the difference ΔV is less than the threshold Th, the label presence / absence determination unit 44 determines that there is no label 14 on the holding member 22 (paper conveyance die 27) (step S28). Thereafter, the process returns to the main program ( Figure 5 )

[0113] (Method for setting the threshold)

[0114] UseFigure 7 A method for setting a threshold Th for determining the presence or absence of a determination label is described. Figure 7 It is a diagram showing a method for setting a threshold for determining the presence or absence of a determination label according to the intensity of external light.

[0115] As Figure 7 shown in the sensor output example Ce, the sensor output V has a form in which a pulse-shaped output corresponding to the lighting of the LED 31 is superimposed on the sensor output V corresponding to the extinguishing of the LED 31. Even when the external light 38 becomes very strong, this form is maintained, but the stronger the external light 38, the greater the sensor output V becomes. As Figure 7 shown in the sensor output example Cf, the sensor output corresponding to the extinguishing of the LED 31 increases from the sensor output Va to the sensor output Vb. Further, since the emitted light 32 when the LED 31 is lit is constant, the stronger the external light 38, the smaller the ratio of the emitted light 32 to the intensity of the external light 38. Therefore, the stronger the external light 38, the smaller the difference ΔV of the sensor output V.

[0116] That is, in Figure 7 the example shown, the difference ΔVb in the case where the external light 38 is strong when there is a label is smaller than the difference ΔVa in the case where the external light 38 is weak when there is a label.

[0117] Therefore, in an environment where the intensity of the external light 38 changes, it is difficult to determine the presence or absence of the label 14 by comparing the difference ΔV with a fixed threshold Th. Therefore, it is expected that the label printer 10 has a function of setting the threshold Th according to the intensity of the external light 38.

[0118] The sensor output V corresponding to the extinguishing of the LED 31 increases as the external light 38 becomes stronger as described above. Then, the difference ΔV decreases as the external light 38 becomes stronger. Therefore, it is expected that the label presence / absence determination unit 44 sets a threshold Th(V) that monotonically decreases according to the sensor output V when the LED 31 is extinguished. More specifically, it is expected that the label presence / absence determination unit 44 has a threshold setting list T as Figure 7 shown, and sets a threshold Th(V) that monotonically decreases according to the increase in the external light 38. In addition, in Figure 7 , the threshold Th(V) linearly decreases as the sensor output V corresponding to the extinguishing of the LED 31 increases, but it is not limited to this. For example, the threshold Th(V) may non-linearly decrease as the sensor output V corresponding to the extinguishing of the LED 31 increases. In addition, the threshold Th(V) is determined using the results of evaluation experiments performed in advance, etc. The setting of the threshold Th(V) can be performed at any time by the operation of the operator, etc., but it can also be automatically executed at the start of printing. The process of automatically setting the threshold Th(V) at the start of printing will be described later.

[0119] In addition, although not shown, depending on the lighting conditions of the environment in which the label printer 10 is set, there may be a flickering situation where the brightness of the illumination changes periodically. When flickering occurs, the change in the illumination light caused by the flickering is superimposed on the sensor output V. Therefore, it is possible to calculate a difference ΔV that is different from the actual value based on the time of the sensor output V when the LED 31 is off and the time of the sensor output V when the LED 31 is on.

[0120] In order to reduce the influence of such flickering, the label presence / absence determination unit 44 may also calculate the average value of the sensor output V during the off period pb of the LED 31 and the on period pa of the LED 31, respectively, and calculate the difference ΔV based on the average value of the sensor output V when the LED 31 is off and the average value of the sensor output V when the LED 31 is on that are calculated. In addition to the average value, the maximum value during the period or the minimum value during the period may be calculated.

[0121] The label presence / absence determination unit 44 may also perform a process of setting a threshold value (threshold value setting process) when the label printer 10 starts printing. It is premised that there is no label on the holding member 22 at the start of use. Specifically, the threshold value setting process is as follows. At the same time as the print control unit 45 instructs the start of printing, a printed label 14 is issued and held on the holding member 22. After that, the label presence / absence determination unit 44 turns off the LED 31 of the light irradiation unit 41. Based on the sensor output V (first signal) detected by the light receiving element 34 and the threshold value setting list T, a threshold value Th corresponding to the intensity of the current external light 38 is set. After that, the label presence / absence determination process (S12) is performed. By doing so, a threshold value corresponding to the intensity of the external light 38 at the start of printing can be set.

[0122] (Function and effect of the embodiment)

[0123] As described above, the label printer 10 of the first embodiment includes: a light irradiation unit 41 that irradiates light to an area where the printed label 14 exists and is irradiated by the external light 38, a light irradiation control unit 42 that switches between light irradiation and non-irradiation by the light irradiation unit 41, a light receiving unit 43 that obtains a light signal from the area where the printed label 14 exists in synchronization with the switching between light irradiation and non-irradiation by the light irradiation control unit 42, and a label presence / absence determination unit 44 that determines the presence or absence of the label 14 based on a first signal obtained by the light receiving unit 43 when the light irradiation unit 41 does not irradiate light and a second signal obtained by the light receiving unit 43 when the light irradiation unit 41 irradiates light. Therefore, even if the printed label 14 is in a position irradiated by the external light 38, the presence of the label 14 can be reliably detected.

[0124] In addition, in the label printer 10 of the first embodiment, the light irradiation unit 41 and the light receiving unit 43 are provided on the same side of the label surface of the label 14 that has been printed. Therefore, the light irradiation unit 41 and the light receiving unit 43 can be provided in a smaller space.

[0125] In addition, in the label printer 10 of the first embodiment, the label presence / absence determination unit 44 determines the presence / absence of the label 14 that has been printed based on the magnitude relationship between the difference ΔV between the level of the first signal and the level of the second signal and the threshold Th. Therefore, the presence / absence of the label 14 can be detected by simple signal processing.

[0126] In addition, in the label printer 10 of the first embodiment, the label presence / absence determination unit 44 sets the threshold Th(V) based on the level of the first signal (sensor output V). Therefore, even when the intensity of the external light 38 changes, the presence / absence of the label 14 can be reliably detected.

[0127] In addition, the label printer 10 of the first embodiment further includes a print control unit 45. The print control unit 45 temporarily stops the printing of the next label 14 on the condition that the label presence / absence determination unit 44 determines that there is a label 14, and starts the printing of the next label 14 on the condition that the label presence / absence determination unit 44 determines that there is no label 14. Therefore, it is possible to prevent the printed label 14 from staying at the discharge port 21.

[0128] (Second Embodiment)

[0129] Hereinafter, with reference to the drawings, a second embodiment of the label printer according to the embodiment of the present invention will be described in detail.

[0130] (Overall Configuration of Label Printer)

[0131] Use Figure 8 The schematic configuration of the label printer 40 according to the second embodiment will be described. Figure 8 FIG. is a cross-sectional view showing an example of the internal structure of the label printer according to the second embodiment. In addition, the label printer 40 is an example of the printer device in the present disclosure.

[0132] The label printer 40 includes a label reel 12 inside the housing 11 that winds a linerless label paper 26, which is an example of a printing paper, into a roll shape. In addition, the label printer 40 prints while pulling out the linerless label paper 26 from the label reel 12.

[0133] The surface of the linerless label paper 26 serves as a printing surface, and the back surface serves as an adhesive surface. That is, the linerless label paper 26 does not have a release paper 15 (refer to Figure 1The label paper. The linerless label paper 26 pulled out from the label roll 12 is conveyed toward the discharge port 36 while being clamped between the paper pressing roller 17 and the thermal printer 16. At this time, the printing surface of the linerless label paper 26 is on the side of the thermal print head 16. In addition, the linerless label paper 26 is an example of the label in the present disclosure.

[0134] The thermal print head 16 prints on the printing surface of the linerless label paper 26 clamped between it and the paper pressing roller 17. In addition, the label printer 40 may also be a type that clamps an unillustrated ink ribbon between the thermal print head 16 and the linerless label paper 26, and transfers the ink of the ink ribbon heated by the thermal print head 16 to the printing surface of the linerless label paper 26 for printing.

[0135] The linerless label paper 26 discharged from the discharge port 36 stays at the position above the holding member 22. Then, the linerless label paper 26 is cut by the cutter 28 provided on the upstream side of the holding member 22 and removed from above the holding member 22. The cutter 28 is composed of a fixed blade 29 provided on the back side of the linerless label paper 26 and a movable blade 30 provided on the printing surface side of the linerless label paper 26, and can be cut either by the manual operation of the operator or automatically in conjunction with the end of printing.

[0136] A label sensor 24 for detecting the presence or absence of the linerless label paper 26 (label) is provided at the position of the holding member 22. The label sensor 24 is above the holding member 22 and is provided at a position opposite to the label surface of the linerless label paper 26 across the linerless label paper 26 to detect the presence of the linerless label paper 26. When the label sensor 24 detects the linerless label paper 26, the label printer 40 temporarily stops the conveyance and printing of the linerless label paper 26. Then, when the user removes the linerless label paper 26 that has been printed, the label sensor 24 detects the absence of the linerless label paper 26 and resumes the conveyance and printing of the linerless label paper 26. In addition, the structure and operation principle of the label sensor 24 will be described later.

[0137] In addition, since the functional configuration of the label printer 40 is the same as the functional configuration of the above-described label printer 10 (refer to Figure 4 ), the description thereof is omitted. In addition, in the following description, the same symbols as those used in Figure 4 are used in the description of each functional part of the label printer 40.

[0138] (Structure and operation principle of the label sensor)

[0139] Use Figure 9 and Figure 10 to describe the structure and operation principle of the label sensor 24. Figure 9This is a diagram showing the structure and operating principle of the label sensor included in the label printer according to the second embodiment. Figure 10 This is a diagram showing an example of the signal output detected by the label sensor under external light.

[0140] The label sensor 24 includes a light-emitting element 31 and a light-receiving element 34. The light-emitting element 31 irradiates light at a predetermined cycle by the action of a drive circuit (not shown). The light-emitting element 31 is, for example, an LED. In addition, although the wavelength of the light irradiated by the light-emitting element 31 is not limited, it is desirable to use near-infrared light, which is invisible light. Further, it is desirable that the light-receiving element 34 is a light-receiving element that is highly sensitive to light having the same wavelength as the light irradiated by the light-emitting element 31. Therefore, a filter that transmits light having the wavelength irradiated by the light-emitting element 31 may be provided on the surface of the light-receiving element 34.

[0141] The light-receiving element 34 outputs an electric signal corresponding to the amount of received light in synchronization with the time when the light-emitting element 31 irradiates light. The light-receiving element 34 is, for example, a photodiode. In this way, the label sensor 24 is a transmissive sensor in which the light-receiving element 34 detects the transmitted light of the light irradiated by the light-emitting element 31.

[0142] The light-emitting element 31 and the light-receiving element 34 are provided at opposite positions with the paper feed die 27 formed on the upper part of the holding member 22 therebetween. The light-emitting element 31 irradiates light upward from the gap 35 of the paper feed die 27 formed on the upper part of the holding member 22 to the holding member 22. The light-receiving element 34 detects the light transmitted through the gap 35. In addition, the gap 35 is a gap formed by cutting a part of the paper feed die 27 along the direction in which the linerless label paper 26 is discharged, that is, the X axis.

[0143] Figure 9 The detection state Sf shown indicates a case where the emitted light 32 irradiated by the LED 31 is blocked by the linerless label paper 26 and the emitted light 32 is not detected by the light-receiving element 34.

[0144] At this time, as shown in the detection state Sg, after the emitted light 32 irradiated by the LED 31 passes through the gap 35, it irradiates the adhesive surface of the linerless label paper 26. Thereafter, although a part of the emitted light 32 passes through the linerless label paper 26 and reaches the light-receiving element 34, the amount of the emitted light 32 passing through the linerless label paper 26 is small. Therefore, compared with the case where there is no emitted light 32, the light-receiving element 34 outputs a slightly larger sensor output V.

[0145] On the other hand, when there is no linerless label paper 26 above the paper feed die 27, as Figure 9In the detection state Sh as shown, after the emitted light 32 irradiated by the LED 31 passes through the gap 35, it passes above the paper conveyance die 27 (positive Z-axis side). Thereafter, the light receiving element 34 detects the emitted light 32 of the LED 31. Therefore, compared with the case where there is no emitted light 32, the light receiving element 34 outputs a larger sensor output V.

[0146] Next, use Figure 10 to explain the signal output detected by the label sensor 24 under the external light 38.

[0147] The paper conveyance die 27 is located on the surface of the housing 11 to facilitate the removal of the unlined label paper 26 that has been printed. In addition, external light 38 in the environment where the label printer 40 is provided is irradiated through the gap between the paper conveyance die 27 and the light receiving element 34 on the printing surface of the unlined label paper 26 that has been printed. The external light 38 includes indoor lighting such as fluorescent lamps, incandescent lamps, and LED lighting, and sunlight. Such external light 38 sometimes has an adverse effect when the label sensor 24 detects the presence or absence of the unlined label paper 26.

[0148] Figure 10 The detection state Si as shown indicates a situation where external light 38 is irradiated on the printing surface of the unlined label paper 26 in a state where the unlined label paper 26 that has finished printing is on the paper conveyance die 27.

[0149] In the detection state Si, the emitted light 32 from the LED 31 irradiates the back surface (adhesive surface) of the unlined label paper 26. In addition, although a part of the emitted light 32 passes through the unlined label paper 26 and reaches the light receiving element 34, the sensor output V output by the light receiving element 34 is very small. Then, at this time, when external light 38 is irradiated on the surface of the unlined label paper 26, a part of the external light 38 is reflected on the surface of the unlined label paper 26 and reaches the light receiving element 34. Therefore, in the detection state Si, regardless of whether the LED 31 irradiates the emitted light 32 or not, the light receiving element 34 outputs a larger sensor output V compared with the case where there is no external light 38. Thereafter, as described above, the sensor output V based on the emitted light 32 from the LED is very small. Therefore, when the difference between the sensor output V obtained when the LED 31 irradiates the emitted light 32 and the sensor output V obtained in a state where the LED 31 does not irradiate the emitted light 32 by the label sensor 24 is less than a preset threshold value, the presence or absence of the unlined label paper 26 can be determined.

[0150] On the other hand, as Figure 10 shown, the detection state Sj indicates a situation where external light 38 is irradiated in a state where there is no unlined label paper 26 on the paper conveyance die 27.

[0151] In the detection state Sj, the emitted light 32 from the LED 31 passes through the gap 35 of the paper conveyance die 27 (refer to Figure 9 ), and reaches the light receiving element 34. Therefore, the emitted light 32 is detected by the light receiving element 34. At this time, a part of the external light 38 irradiated on the surface of the paper conveyance die 27 also reaches the light receiving element 34. Therefore, the light receiving element 34 outputs a sensor output V obtained by adding the reflected light of the emitted light 32 from the LED 31 and the external light 38.

[0152] In addition, the sensor output V obtained when the LED 31 irradiates the emitted light 32 is larger than the sensor output V obtained in the state where the LED 31 does not irradiate the emitted light 32. Therefore, regardless of the intensity of the external light 38, when the difference between the sensor output V obtained when the LED 31 irradiates the emitted light 32 and the sensor output V obtained in the state where the LED 31 does not irradiate the emitted light 32 is greater than or equal to a preset threshold value, it can be determined that there is no label-free paper 26.

[0153] Hereinafter, a method for determining the presence or absence of the label-free paper 26 will be described based on the waveform of the actual sensor output V. Figure 10 The illustrated sensor output example Cg represents an example of the sensor output V in the state where there is or is not the label-free paper 26 on the paper conveyance die 27 and in the absence of the external light 38.

[0154] The LED 31 Figure 10 switches between the lit state and the extinguished state at the same time as described in any of the illustrated states Figure 3 and repeats.

[0155] At this time, the sensor output V output by the light receiving element 34 has a pulse waveform as shown in the sensor output example Cg. That is, a very small sensor output V is obtained during the extinguished period pb of the LED 31. Then, during the lit period pa, a part of the emitted light 32 from the LED 31 passes through the label-free paper 26, and a sensor output V slightly larger than that during the extinguished period pb of the LED 31 is obtained. Thereafter, a very small difference ΔV is generated between the sensor output V during the lit period pa and the sensor output V during the extinguished period pb.

[0156] In contrast, Figure 10 the illustrated sensor output example Ch shows an example of the sensor output V in the state where there is no label-free paper 26 on the paper conveyance die 27 and in the absence of the external light 38. The lighting and extinguishing times of the LED 31 in the sensor output example Ch are the same as those described in the sensor output example Ca (refer to Figure 3 ).

[0157] At this time, as shown in the sensor output example Ch, the light-receiving element 34 generates a sensor output V corresponding to the emitted light 32 of the LED 31 during the lighting period pa of the LED 31. Then, a difference ΔV is generated between the sensor output V during the lighting period pa and the sensor output V during the non-lighting period pb. The difference ΔV generated at this time is a larger value compared to the difference ΔV generated in the sensor output example Cg because the emitted light 32 of the LED 31 directly enters the light-receiving element 34.

[0158] From the comparison between the sensor output example Cg and the sensor output example Ch, it can be seen that in the absence of external light 38, by comparing the difference ΔV between the sensor output V during the lighting period pa and the sensor output V during the non-lighting period pb with a threshold value, when the difference ΔV is greater than or equal to the threshold value, it can be determined that the label-free paper sheet 26 does not exist. In addition, it can be seen that when the difference ΔV is less than the threshold value, it can be determined that the label-free paper sheet 26 exists.

[0159] Figure 10 The shown sensor output example Ci represents an example of the sensor output V in the case where there is external light 38 and there is a label-free paper sheet 26 on the paper conveyance die 27. The lighting and non-lighting times of the LED 31 in the sensor output example Ci are the same as those described in the sensor output example Ca.

[0160] At this time, the sensor output V output by the light-receiving element 34 has a pulse waveform as shown in the sensor output example Ci. That is, during the non-lighting period pb of the LED 31, the sensor output V is an almost equal value corresponding to the intensity of the reflected light of the label-free paper sheet 26 of the external light 38. In addition, during the lighting period pa of the LED 31, a part of the emitted light 32 of the LED 31 passes through the label-free paper sheet 26 and reaches the light-receiving element 34, thereby obtaining a sensor output V slightly larger than that during the non-lighting period pb of the LED 31. Then, a very small difference ΔV is generated between the sensor output V during the lighting period pa and the sensor output V during the non-lighting period pb.

[0161] Regarding this, Figure 10 The shown sensor output example Cj shows an example of the sensor output V in the case where there is no label-free paper sheet 26 on the paper conveyance die 27 and there is external light 38. The lighting and non-lighting times of the LED 31 in the sensor output example Cj are the same as those described in the sensor output example Ca.

[0162] At this time, the sensor output V output by the light receiving element 34 has a pulse waveform as shown in the sensor output example Cj. That is, during the light-off period pb of the LED 31, the sensor output V corresponding to the intensity of the reflected light of the external light 38 on the paper conveyance die 27 is obtained. When the paper conveyance die 27 is a dark color with a low reflectance, the sensor output V is smaller in the sensor output example Ci than the sensor output V during the light-off period pb of the LED 31. In addition, the sensor output V obtained during the light-on period pa of the LED 31 is only a value larger than the part where the emitted light 32 of the LED 31 passing through the paper conveyance die 27 reaches the light receiving element 34 with respect to the sensor output V obtained during the light-off period pb of the LED 31. Then, a difference ΔV larger than the difference ΔV generated in the sensor output example Ci is generated between the sensor output V during the light-on period pa and the sensor output V during the light-off period pb.

[0163] From the comparison between the sensor output example Ci and the sensor output example Cj, it can be seen that in the presence of the external light 38, by comparing the difference ΔV between the sensor output V during the light-on period pa and the sensor output V during the light-off period pb with a threshold value, when the difference ΔV is greater than or equal to the threshold value, it can be determined that there is no label-free paper 26. In addition, it can be seen that when the difference ΔV is less than the threshold value, it can be determined that there is label-free paper 26.

[0164] It can be seen that, that is, regardless of the presence or absence of the external light 38, by comparing the difference ΔV between the sensor output V during the light-on period pa and the sensor output V during the light-off period pb with a threshold value, and when the difference ΔV is greater than or equal to the threshold value, it can be determined that there is no label-free paper 26. In addition, it can be seen that when the difference ΔV is less than the threshold value, it can be determined that there is label-free paper 26.

[0165] (Flow of the printing operation performed by the label printer)

[0166] Use Figure 11 To explain the flow of the printing process performed by the label printer 40. Figure 11 It is a flowchart showing an example of the flow of the printing operation of the label printer according to the second embodiment.

[0167] The print control unit 45 instructs each part of the label printer 40 to start printing (step S31).

[0168] The label presence / absence determination unit 44 performs a label presence / absence determination process for determining the presence or absence of the label-free paper 26 (step S32). When it is determined that there is label-free paper 26, it proceeds to step S33. On the other hand, when it is not determined that there is label-free paper 26, it proceeds to step S35. In addition, the detailed flow of the label presence / absence determination process is the same as the flow of the above process (refer to Figure 6) The same. However, only the magnitude relationship between the difference ΔV of the sensor output V and the threshold Th is different from that of the first embodiment. That is, in this embodiment, when the difference ΔV is greater than or equal to the threshold Th, it is determined that there is no unlined label paper 26. In addition, when the difference ΔV is less than the threshold Th, it is determined that there is unlined label paper 26.

[0169] In step S32, when it is determined that there is unlined label paper 26, the print control unit 45 temporarily stops the printing operation (step S33).

[0170] Next, the print control unit 45 cuts the unlined label paper 26 by the cutter 28 (step S34). After that, it returns to step S32. In addition, the cutting of the unlined label paper 26 can also be performed by the user operating the cutter 28 himself.

[0171] In step S32, when it is determined that there is no unlined label paper 26, that is, when the printed unlined label paper 26 is removed from the holding member 22, the print control unit 45 determines whether a prescribed number of unlined label papers 26 have been printed (step S35). When it is determined that a prescribed number of unlined label papers 26 have been printed (step S35: Yes), the label printer 40 ends Figure 11 the process. On the other hand, when it is not determined that a prescribed number of unlined label papers 26 have been printed (step S35: No), it advances to step S36.

[0172] In step S35, when it is not determined that a prescribed number of unlined label papers 26 have been printed, the print control unit 45 restarts printing (step S36).

[0173] The print control unit 45 increments the number of printed unlined label papers 26 (step S37). After that, it returns to step S32.

[0174] (Function and effect of the embodiment)

[0175] As described above, in the label printer 40 of the second embodiment, the light irradiation unit 41 and the light receiving unit 43 are provided at positions opposite to each other across the label surface of the printed unlined label paper 26. Therefore, compared with the case of using a reflection-type sensor, since the amount of external light 38 incident on the light receiving element 34 becomes smaller, the influence of the external light 38 can be reduced.

[0176] In addition, in the first embodiment, the content that the peeling sensor 23 is constituted by a reflection-type sensor is described. In the second embodiment, the content that the label sensor 24 is constituted by a transmissive sensor is described. However, the peeling sensor 23 can be constituted by a transmissive sensor, and the label sensor 24 can also be constituted by a reflection-type sensor.

[0177] As mentioned above, although the embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. In addition, these embodiments and their modifications are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the scope of equivalents thereof.

Claims

1. A printer device, characterized in that, Comprising: A light irradiation unit that irradiates light to an area irradiated by external light where a label that has been printed is present; A light irradiation control unit that switches between irradiation and non-irradiation of light by the light irradiation unit; A light receiving unit that, in synchronization with the switching of irradiation and non-irradiation of light by the light irradiation control unit, obtains an optical signal from the area where a label that has been printed is present; And A label presence / absence determination unit that determines the presence or absence of a label based on a first signal obtained by the light receiving unit when the light irradiation unit does not irradiate light and a second signal obtained by the light receiving unit when the light irradiation unit irradiates light, wherein the label presence / absence determination unit determines the presence or absence of the label based on the magnitude relationship between the difference in the level of the first signal and the level of the second signal and a threshold value, moreover, the label presence / absence determination unit sets the threshold value based on the level of the first signal, moreover, the label presence / absence determination unit has a threshold setting list in which the threshold value decreases as external light increases, and sets the threshold value based on the level of the first signal and the threshold setting list, moreover, the label presence / absence determination unit sets the threshold value at the start of printing.

2. The printer device according to claim 1, wherein the light irradiation unit and the light receiving unit are provided on the same side of the label surface of the label that has been printed.

3. The printer device according to claim 1, wherein the light irradiation unit and the light receiving unit are provided at positions opposite to each other across the label surface of the label that has been printed.

4. The printer device according to any one of claims 1 to 3, further comprising: A print control unit that temporarily stops printing of the next label on the condition that the label presence / absence determination unit determines that a label is present, and starts printing of the next label on the condition that the label presence / absence determination unit determines that no label is present.

5. The printer device according to claim 1, wherein the label presence / absence determination unit sets the threshold value based on the level of the first signal obtained by the light receiving unit when the light irradiation unit does not irradiate light in a state where a label that has been printed is present and the threshold setting list.

6. The printer device according to claim 1, wherein the label presence / absence determination unit calculates a difference based on the average value of the first signal during the period when the light irradiation unit does not irradiate light and the average value of the second signal during the period when the light irradiation unit irradiates light.

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