JPH0369436A - Label printer - Google Patents

Abstract

PURPOSE:To contrive the simplification of the worker's operation by a method wherein the length of label gap is measured based on changes in the output of a sensor, the results form such measurement are stored and, based on the stored contents and the output of the sensor, the termination of the label is judged. CONSTITUTION:The subject label printer is provided with a sensor 23 for detecting a plurality of labels attached to a backing paper 2 with a predetermined gap, a feed means for feeding the backing paper 2, a measuring means for measuring the length of the gap based on changes in the output of the sensor 23 during feed, a memory means for storing the results from measurement by the measuring means, a judging means for judging the termination of the label based on the contents stored by the memory means and the output of the sensor 23 and an information means for informing the results of judgement by the judging means. Therefore, this device itself can measure the length of the gap automatically and, based on its result, detect the label end part. This method obviates the need for a special manipulation by the worker, even in the case of change in the gap length taking place at the time of changing one kind of label to another.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a label printer that prints in various formats on various types of labels having different sizes and shapes.

``Prior Art'' FIG. 12 is a diagram showing the vicinity of the end of a conventional label paper 1 used in a label printer.
3... is attached in a removable manner and wound into a roll. Furthermore, a gap 4 defined at a constant interval (for example, 2 mm) is formed between each label 3 regardless of its size or shape, and no label is pasted behind the final label 3. An end portion 5 is provided.

By the way, in order to print on the label 3, it is necessary to detect the gap 4 and the label end portion 5. It is installed so as to face the route and uses the signal output from the sensor. That is, when the label paper l passes between the light emitting element and the light receiving element, the amount of transmitted light decreases at the label 3 portion, and the amount of transmitted light increases at the gap 4 and the label end portion 5.

As a result, a signal corresponding to the amount of transmitted light is output from the sensor, and this signal is used to detect the gap 4 and the label end portion 5. The difference between the gap 4 and the label end portion 5 can be detected by continuously outputting a gap signal from the sensor for a period longer than the length of the gap 4 (hereinafter referred to as gap length) (in this case, 2 mm + α). This is done by determining that the case is label end portion 5.

"Problem to be Solved by the Invention" Recently, the types, sizes, and shapes of products to which labels 3 are affixed have been diversifying, and accordingly, the labels 3 have also been diversifying. However, as described above, the gap length is fixed and is therefore a major constraint on label production.

Also, modified labels, especially circular, pentagonal or hexagonal
In the case of a rectangular label 3, the gap length cannot be set to a specified interval. Therefore, a problem arises in that the gap 4 and the label end portion 5 cannot be detected using the conventional detection method described above.

Therefore, for example, the following method may be considered. First, a list of gear tooth lengths for each type of label 3 is posted near the label printer.

Then, when the label 3 is replaced, the operator reads the gap length of the label 3 from this list and inputs the value manually from the operation section of the label printer.

As a result, the label printer detects the gap 4 and the label end portion 5 based on the input gap length.

However, the above method has the following drawbacks.

■A list of gap lengths must be prepared. Furthermore, when using a new label 3, this list must be rewritten.

- If you lose the list, you will be unable to use your label printer.

■The work for the operator increases.

= 3 ■If you accidentally input the gap length manually from the label printer's operation panel or forget to input it manually when replacing label 3, the label printer will input gap length 4 or label end 5. could not be detected or
The gap 4 may be mistakenly determined to be the label end portion 5.

The present invention has been made in view of the above-mentioned circumstances, and provides a label printer that can accurately detect the label end portion without any special operation by the operator even if the label gap length differs depending on the label type. is intended to provide.

``Means for Solving the Problems-1 The first invention includes a sensor for detecting a plurality of labels pasted on a backing sheet with a predetermined gap formed therein, a feeding means for feeding the backing sheet, and an output of the sensor during feeding. a measuring means for measuring the gap length based on a change in the gap length, a storing means for storing the measurement result of the measuring means, a determining means for determining the end of the label based on the memory contents of the storing means and the output of the sensor, It is characterized by comprising a notification means for notifying the judgment result of the means.

Further, a second invention is characterized in that, in the first invention, the measurement of the gap length by the measuring means is automatically performed after automatic adjustment processing of the output level of the sensor at the time of label replacement.

"Operation" According to the first invention, when the feeding means feeds the mount, the measuring means measures the gap length based on the change in the output of the sensor, and the measurement result of the measuring means is stored in the storage means. Further, the determining means determines whether the label is finished based on the contents stored in the storage means and the output of the sensor, and the notifying means notifies the determination result of the determining means.

Further, according to the second invention, when the label is replaced, the measurement of the gap length by the measuring means is automatically performed after the sensor output level automatic adjustment process is completed.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the electrical configuration of a label printer according to an embodiment of the present invention.
Reference numeral 6 is a CPU (central processing unit) that controls each part of the apparatus, and 7 is a ROM, which is composed of a program area, a print format table, and a character generator. 8 is RAM, a work area, PLU memory,
It consists of tally memory, print buffer memory, and register memory. Reference numeral 9 denotes an operation section consisting of preset keys, a numeric keypad, and function keys, and 10 a display section on which printed contents and various messages are displayed.

Further, reference numeral 11 denotes a printing unit that prints print data on the label 3 based on instructions from the CPU 6, and FIG. 2 shows a front view of the external configuration of the mechanism unit. In this figure, label paper 1
is rotatably mounted on a rotating shaft 12, and passes through a U-shaped guide plate 13, idle rollers 14 and 15, a platen roller 16, and a dispenser 17, where the label 3 and the backing paper 2 are peeled off. Label 3 is discharged to the outside,
It is adapted to be wound up on either the mount 2 or the take-up reel 18.

Here, FIG. 3 shows a sectional view of the driving portions of the platen roller 16 and the take-up reel 18. In this figure, parts corresponding to those in FIG. 2 are given the same reference numerals, and their explanations will be omitted. In FIG. 3, a gear 16a is fitted on the shaft of the platen roller 16, and a gear 18a is fitted on the shaft of the take-up reel 18. Further, the gear 16a meshes with a drive gear 19a fitted to the shaft of the stepping motor 19, and the gear 18a meshes with a drive gear 20a fitted to the shaft of the DC motor 20.

Furthermore, in FIG. 2, 21 is a thermal head, and while pressing the label paper 2 against the platen roller 16,
Perform thermal printing on label 3. 22 is a U-shaped prism provided with the guide plate 13 in between.

Here, FIG. 4 shows a sectional view taken along the line AA in FIG. 2.

In the figure, 23 indicates a light emitting element 24 and a light receiving element 25.
It is a transmission type sensor that detects the label 3 on the label paper 1, and the light emitted from the light emitting element 24 is
The label paper 1 is bent into a U-shape by the prism 22.
The light reaches the light receiving element 25 via.

In addition, in FIG. 1, 26 indicates the CPU 6 and the printing unit 11.
27 is the thermal head 21
28 is a motor drive circuit that drives and controls the stepping motor 19 and the DC motor 20; 29 is a 4-bit digital data 5D (0 to 15) transferred from the CPU 6 through the I10 port 26; A D/A converter 30 inputs the analog signal SA and converts the output level Vo of the sensor 23 into an analog signal SA of 16 levels (for example, when 5D=O, the output level Vo: minimum, 5D=15 This is an output level adjustment circuit that adjusts the output level Vo=maximum when . Also, the output level V of the sensor 23. is compared with a reference voltage E8 in a comparator (not shown). Then, the output signal KS of the comparator is V, when <E, II L
When It level (“O” signal), Vo>E, I
The signal becomes IHI+ level ("°BI'signal)" and is transferred to the CPU 6 via the I10 port 26.

For details of the sensor 23, D/A converter 29, and output level adjustment circuit 30, please refer to the publication of the automatic adjustment device for label position detection sensor previously proposed by the present applicant (Japanese Patent Laid-Open No. 6
0-185104).

In such a configuration, the operator first inserts the label paper 1.
is set in this label printer, the CPU 6 measures the length LL of the label 3 (hereinafter referred to as label length LL) and the length LG of the gap 4 (hereinafter referred to as cap length LG) as shown in Fig. 5. The explanation will be based on a flowchart.

When the operator presses the label feed key, which is one of the function keys on the operation unit 9, after setting the label paper 1 in the label printer, the CPU 6 executes step SA.
Proceeding to process I, the output level V0 of the sensor 23 is adjusted. That is, the output level V. and standard level E, and is the sixth
If the relationship is not as shown in figure (a), the label length L
L and gear length LG cannot be detected accurately. For example, in the case of FIG. 6(b), since both the label 3 and the mount 2 are thin, the output level is V. The whole thing is too big
Furthermore, in the case of FIG. 2C, since both the label 3 and the mount 2 are thick, the output level is V. The whole thing is too small. Therefore, the reference level E5 and the output level V. It is not possible to detect the label length LL and the gear tooth length LG even by comparing them.

Therefore, when the label paper ■ is replaced, first, the output level V of the sensor 23 is changed. must be adjusted. By the way, in the past, the above-mentioned output level V0 was adjusted by manual volume adjustment.
The present applicant has already proposed a device that automatically performs this (the above-mentioned automatic adjustment device for a label position detection sensor).

Therefore, in this embodiment as well, this device is used to automatically adjust the output level V0 of the sensor 23.

Here, the above-mentioned adjustment procedure will be briefly explained. For details, please refer to the publication.

When the operator presses the label feed key, which is one of the function keys on the operation section 9, after setting the label paper 1 in the label printer, the CPU 6 performs the following processing.

■ Transfer the digital data SD by changing it in stages from 0 to 15. This causes the signal KS to become
The value SD of the digital data SD when it changes from I to 1'' is determined.

(2) Next, after feeding the label paper ↓ by a predetermined amount (for example, 3 mm), the same process as (2) is performed to obtain the value SD of the digital data SD at that time.

(2) The values SD and SD are then compared and the larger value is stored as a temporary value.

■Furthermore, search for gap 4 using the temporary value stored in the process of ■, and in this gap 4,
Perform the same process as ■, and then convert the digital data S
A value SDd of D is determined, and an adjustment value SD is determined based on that value (by adding a constant).

As explained above, in the above-described processing, the output level V of the 1 sensor 23 is first determined in the label 3 portion by the processing ① to ②. After performing the temporary adjustment, the true adjustment is performed in the gap 4 by the process (2). This is because the store name and frame are printed on the label 3 in advance, so the output level Vo of the sensor 23 on the label 3 is not constant as shown in FIG. is not printed, and the output level of sensor 23 is V. This is because the level adjustment is performed again in the gap 4 portion where the current is stable.

In addition, in the process (2), the label paper 1 was fed by a predetermined amount because the gear gear length LG of the conventional label paper 1 was constant (for example, 2 mm), so the label paper 1 was fed by a predetermined amount (for example, 3 mm). If you feed it, even if the sensor position is at gap 4 when label paper 1 is set, after feeding, the sensor position will be at label 3 and 2.
If the value SD is found at the location, temporary adjustment can be made using the output level V0 of the sensor 23 at the label 3 portion without being affected by the positional relationship between the label 3 and the sensor 23 when the label paper 1 is set. It is.

2 On the other hand, in this embodiment, the gear tooth length LG
is not constant, so even if the label paper 1 is fed by a predetermined amount (for example, 3 mm) as in the above-mentioned process (■),
There is a possibility that both locations are gap 4 (see Figure 8). Therefore, in this embodiment, the output level V of the sensor 23 is determined by the following processing procedure. Make adjustments.

When the operator presses the label feed key, which is one of the function keys on the operation section 9, after setting the label paper 1 in the label printer, the CPU 6 performs the following processing.

(a) Digital data SD is changed stepwise from 0 to 15 and transferred. This causes the signal KS to be
The value SD of the digital data SD when it changes from "0" to "1" is determined.

(b) Next, add a predetermined amount of label paper 1 (for example, 3 m
m) After feeding, perform the same process as in (a),
The value SD2 of the digital data SD at that time is determined.

(c) Then, the judgment shown in the following equation is made.

5Dn-1-3Do1≧a (for example, 10)...■(
d) If the judgment result in (c) is rYEsl, the value S
Compare D n-1 and the value SDn, determine that the smaller value is the value at gap 4, and determine the adjustment value SD based on that value (by adding a constant, for example, 3) do.

(e) On the other hand, if the determination result in (C) is rNOJ, the processes in (b) and (c) are repeated.

In addition, in the process (b), if the feed amount is set to the minimum gear length LG or less among the various label papers 1,
-1- Gap 4 can always be detected by the processes (a) to (e) described above. Then, the process advances to step SA2.

Further, as described above, since the conventional label paper 1 has a constant cap length LG, the output level V of the sensor 23
. When the adjustment was completed, the sensor 23 was always in a state of detecting the gap 4.

On the other hand, in this embodiment, the gear tooth length ■,
Since G is not constant, the output level of sensor 23 is V. When the adjustment is completed, the sensor 23 may have detected the label 3. Therefore, in step SA2,
Perform the following processing.

In step SA2, it is determined based on the signal KS whether it is the cap 4 or the label 3 that the sensor 23 is currently detecting. If the result of this determination is rYEsJ, that is, if the signal KS is 0', it is determined that the label is 3 and the process proceeds to step SA3.

In step SA3, the label paper 1 is fed until the signal KS becomes 1'', that is, until the gear knob 4 is detected, and then the process proceeds to step SA2l.

In step SA4, the gear knob length is 1. Measure G.

That is, the CPU 6 moves the platen roller 16 one step (
The label paper 1 is fed while being rotated by a stepping motor 19 by approximately 0155 mm).
The internal counter changes the signal KS from “1” to II.
After counting the number of steps of the stepping motor 19 until OII is reached, the process advances to step SA5.

5 In step SA5, the label length LL is measured.

That is, the CPU 6 rotates the platen roller 16 one step at a time by the stepping motor 19 and feeds the label paper 1, and also uses an internal counter to step the signal KS from 'O'° to '1pa. After counting the number of steps of the motor 19, the process advances to step SA9.

On the other hand, if the determination result in step SA2 is "NO", that is, if the signal is KS or ''BI, it is determined that the cap 4 is detected by the sensor 23, and step SA2 is performed.
Proceed to step 6.

In step SA6, the label paper 1 is fed until the signal KS becomes "0", that is, until the label 3 is detected, and then the process proceeds to step SA7.

In step SA7, the label length LL is measured.

That is, the CPU 6 rotates the platen roller 16 one step at a time by the stepping motor 19 and feeds the label paper (2), and also controls the stepping motor 19 to rotate the platen roller 16 one step at a time until the signal KS changes from "0'" to "1". After counting the number of steno knobs to 6, proceed to step SA8.

In step SA3, the gear tooth length LG is determined as ff1l+. That is, the CPU 6 feeds the label paper 1 while rotating the platen roller 16 one step at a time by the stepping motor 19, and also controls the stepper knob of the stepping motor 19 until the signal KS changes from "1" to O by an internal counter. After counting the number, the process advances to step SA9.

In step SA9, control data L
Proceed to step 5 AIQ.

LX=A-Nx(LL-to LG)・
・ ・ ■L Y = L G + B・・・・
...... ■Here, data L The distance is determined by the number of steps of the stepping motor 19, and is preset by the number of steps of the stepping motor 19. Data N is the quotient of A/(LL+LG) (that is, data LX is the remainder when eight is divided by (LL+LG)).

Data LY is label end detection data, and is a value obtained by adding a margin B (for example, 5 steps) to the gear length LG. The relationship between these data is shown in a simplified manner in FIG. In FIG. 9, parts corresponding to those in FIG. 12 are given the same reference numerals, and their explanations will be omitted.

In step 5AIO, the label 3 is fed and set at the printing position based on the calculation result LX in step SB2. That is, when the sensor 23 detects the label 3 and has been fed by a distance LX, the feeding is stopped.

Then, the series of tasks is completed.

Next, the operation of the CPU 6 to print print data on the label 3 will be explained based on the flowcharts of FIGS. 10 and 11.

When the operator presses the print key, which is one of the function keys, after inputting print data (product number) and the number of labels 3 to be issued using the numeric keys on the operation unit 9, the CPU 6 executes step SB2. Proceed to the processing of R
After reading the format data corresponding to the print data from the print format table of OM7 and writing the print image on the print buffer memory of RAM8 according to the print format, the process advances to step SB2. For details of this process, please refer to the publication of the printer previously proposed by the present applicant (Japanese Patent Laid-Open No. 197272/1983).

In step SB2, the manually entered number data of the labels 3 is set in a counter in the register memory of the RAM 8, and then the process proceeds to step SB3.

In step SB3, one line of print data is read from the print buffer memory of RAM8, and
Supply to 7. Thereby, the thermal head 21 prints the print data for t lives on the label 3, and then proceeds to step SB4. For details, please refer to the above-mentioned printer publication.

In step SB4, the motor drive circuit 28 drives the 9-res chipping motor 19 by one step, and then the process advances to step SB5.

In step SB5, it is determined whether or not the label end portion 5 has been detected. If the label end portion 5 has been detected, the label end flag LEF is set, and then the process proceeds to step SB6.

Here, the first part of the label end detection subroutine of step SB5 will be explained based on the flowchart shown in the figure.

In step 5B501, it is determined based on the signal KS of the sensor 23 whether it is the gap 4 or the label 3 that the sensor 23 is currently detecting.

If this judgment result is rYESJ, that is, the signal KS
If it is "■", it is determined that the gap is 4 and the process proceeds to step 5B502.

In step 5B502, the gap counter GC is incremented, and then the process proceeds to step 5B504.

On the other hand, if the determination result in step 5B501 is rNOJ, that is, if the signal KS is II OII, 0 is determined to be label 3, and the process proceeds to step 5B503.

In step 5B503, the gap counter GC is reset, and then the process returns.

Further, in step 5B504, the gap counter CC
It is determined whether the value is greater than or equal to the label end data LY. If the result of this judgment is rNOJ, the process returns.

On the other hand, if the determination result in step 5B504 is "rYES", the process advances to step 5B505.

In step 5B505, the label end flag LEF is set, and then the process returns.

Next, in step SB6, it is determined whether printing on one label has been completed. Note that this judgment is made based on whether the feed distance after starting printing has reached the label length LL. If the result of this determination is rNOJ, the process advances to step SB7.

In step SB7, the line counter is incremented, and then the process returns to step SB3.

On the other hand, if the determination result at step SB6 is rY E S J, the process advances to step SB8.

In step SB3, it is determined whether the label end portion 5 has been detected. That is, the label end flag L E F
Determine whether or not is set.

If the determination result is rYEsJ, that is, if the label end portion 5 is detected, the process advances to step SB9.

In step SB9, the label length LL and the gear length ``LG'' are
After subtracting the distance already fed from the start of printing on one label 3 from the value obtained by adding the above, the remaining distance is fed, and then the process proceeds to step 5BIQ. That is, no matter where the label end portion 5 is detected, the label length L and the gear tooth length L
After feeding the value added with G, the feeding ends. As a result, no matter at what point the label end portion 5 is detected during printing, the stop position is the same as in the case of the end of normal printing.

In step 5B10, after warning that it is the Rahel end part 5 by a buzzer or display on the display [O],
Finish the series of processing.

The above display content is, for example, the following sentence.

"The label has expired. Please replace it with a new label.

” On the other hand, if the determination result in step SB8 is rNOJ, the process advances to step 5B11.

In step 5BII, the motor drive circuit 28 drives the stepping motor 19 one step, and then the process advances to step 5B12.

In step 5B12, as in step SB5, it is determined whether or not the label end portion 5 has been detected. If the label end portion 5 has been detected, the label end flag LEF is set, and the process then proceeds to step 5B10.

In step 5B13, the stop position, that is, the next label 3
is fed to the print start position.

This determination is made by determining whether or not the distance LX has been fed after the sensor 23 detects the tip of the label 3 (that is, after the signal KS changes from "BI" to "0°").The result of this determination is If is rNOJ, the process returns to step 5I38.

3 On the other hand, the judgment result of step S B l, 3 is rY E
If SJ, proceed to step 5BI4.

In step 5B14, it is determined whether the number of printed labels has reached the set number of issued labels. This judgment result is rY
In the case of E S J, the series of processing ends.

On the other hand, if the determination result in step 5B14 is "NO", the process advances to step SB15.

In step 5B15, the label counter is incremented, and then the process returns to step SB3.

Note that in the above-described embodiment, the output level V of the sensor 23. Although an example has been shown in which the adjustment is automated, this adjustment may also be done manually by adjusting the volume as in the past.

Also, the output level V of the sensor 23. Instead, the reference voltage may be changed, both the output level V0 and the reference voltage may be changed, or the amount of light emitted from the light emitting element of the sensor 23 may be changed manually or automatically.

Further, in the embodiment described above, the output level V of the sensor 243. The amount of labels 3 fed by adjusting the label length LL and measuring the gear lug length LG will be wasted. However, this problem can be solved by making the mechanical section shown in FIG. 2 have a structure that allows the label paper 1 to be rewound. The structure of the mechanism for rewinding the label paper 1 as described above is described in detail in the publication of the label printer previously proposed by the present applicant (Japanese Patent Application Laid-Open No. 1983-1.2439). Therefore, the explanation thereof will be omitted.

Furthermore, in the embodiment described above, the mechanism section in FIG.
- We have shown an example of a peel-off type (a type in which the label 3 is peeled off from the mount 2 when it is printed) and does not have a removable cassette type; It may be a type in which the printed label 3 is issued along with the mount 2), or the above-mentioned Japanese Patent Application Laid-Open No. 1986-
], a cassette type as shown in FIG. 4 of Publication No. 85104 may be used. In this case, since the replacement of the label 3 can be automatically detected by the cassette attachment detection sensor and the cassette type detection sensor, the process shown in FIG. 5 can be started automatically without the operator operating the feed key. be able to.

Also, 1. In the flowchart of the label printing process in FIGS. 10 and 11 of the embodiment described above, the control data LX in step 5B13 and the control data LX in step 5B5
As for the control data LY in 04, an example has been described in which the data obtained in the flowchart of FIG. 5 is used.

However, since the latest label length LL and gear gear length LG can always be measured using the signal KS during printing operation, the control data LX and LY always have the latest value L.
It may be configured to recalculate using L and LG and constantly update.

Further, in the flowchart of the label printing process in FIGS. 10 and 11 of the above-described embodiment, step S
B9 is not limited to the processing described above. In other words, in the embodiment described above, there are three labels 3 between the thermal head 21 and the sensor 23, so when the label end portion 5 is detected, the processing of FIG. The feed stops while label 3 is still inside, and a label end warning is issued. However, since the label length LL and the gap length LG have already been measured, printing can also be performed on the three labels 3 described above using these data. Moreover, after detecting the label end portion 5,
It is also possible to feed one blank label 3 and then stop. In short, even if the label end part 5 is detected while printing the label 3, instead of stopping the foot at that point, it prints on the built-in label 3 and then issues the printed label 3. In other words, as long as the rear end of the label 3 is fed completely out of the issuing port, the label 3 can be stopped at any point.

"Effects of the Invention" As explained above, the first invention has the following effects.

■The device itself automatically measures the cap length and detects the label end based on the measurement results, so the operator can replace the label type and perform special operations even if the gap length changes. There's no need.

■Since the gap length is not input by the operator, there is no risk of malfunction of the device due to incorrect input.

■Since control is based on the actual measured value of the gap length, there will be no malfunction of the device even if there is an error in the gap during label manufacturing.

Further, according to the second invention, there are the following effects.

■Gap length measurement is performed automatically along with the automatic adjustment of the sensor output level, which is always necessary when replacing a label, so the operator only needs to perform the same operations as before when replacing a label. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of a label printer according to an embodiment of the present invention, FIG. 2 is a front view showing the external configuration of the mechanical part of the same embodiment, and FIG. 3 is a block diagram showing the platen roller 16 and the winding - Sectional view showing the configuration of the drive section of the rule 18, No. 4
The figure is a sectional view taken along the line AA in FIG. 2, FIG. 5 is a flowchart showing the operation of the CPU 6 to measure the label length LL and the gear lug length LG, and FIGS. 6 and 7 show the output level V of the sensor 23, respectively. FIGS. 8 and 9 are diagrams for explaining the operation of the CPU 6, respectively. FIGS. 10 and 11 are flowcharts showing the operation of the CPU 6 in print processing, and FIG. FIG. 2 is a perspective view showing an example of the configuration of a label paper l. l... Label paper, 2... Mounting paper, 3...
...Label, 4...Gap, 5...
・Label end part, 6... CPU, 8... RAM,
10...Display section, 19.Stepping motor, 23.
...Sensor.

Claims (2)

[Claims] (1) A sensor that detects a plurality of labels pasted on a backing paper with a predetermined gap formed therein, a feeding means that feeds the backing paper, and a sensor that detects the gap length based on a change in the output of the sensor during the feeding. A measuring means for measuring, a storage means for storing the measurement results of the measuring means, a determining means for determining the end of the label based on the storage contents of the storing means and the output of the sensor, and a determination by the determining means. A label printer characterized in that it comprises a notification means for notifying a result. (2) The label printer according to claim 1, wherein the measurement of the gap length by the measuring means is automatically performed after automatic adjustment processing of the output level of the sensor at the time of label replacement.