JPS61181669A - Label printer - Google Patents

Abstract

PURPOSE:To prevent mal-issuing of labels by using a sensor consisting of a projector having a short light permeating distance with comparatively low accuracy and a light receiver. CONSTITUTION:In case where a printing head 20 is not set rightly, or when both ends of latch bars are not coupled with coupling grooves 32a on imperfectly coupled, light detection signal showing that detection light is received from a light receiver is not sent out, and thereby mal-setting of the head 20 is detected. In this case, since the amount of light from a luminous diode 27a is increased, the detection light permeates a label B even when there is the issued label B on a releasing part 23, and the setting condition of the head 20 is confirmed. In case where the head 20 is not set rightly, an error processing, such as displaying of mal-setting of the head 20, etc., is made by a micro-com puter, and the action is finished without issuing the next label.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a label printer that issues a label on which the price of a product to be weighed is printed in conjunction with, for example, a weight detector. The present invention relates to a printing device for a manual label printer that is taken out and attached to a product.

(Prior technology) The fffffi detector calculates the price of the product from the weight signal of the product to be weighed sent from the detector and the preset unit price, tare weight, etc. 2. Description of the Related Art Label printers that print weight and other information on labels and issue labels that can be taken out by workers have been put into practical use. As shown in FIG. 11, the printing device of this type of label printer generally includes a print head 1 and a large number of labels B and B on a strip-shaped mount A.
It has a head receiving member 2, such as a platen roller, to which the print head 1 is pressed while sandwiching a label sheet C formed by removably pasting the label sheet C, and a peeling member 3 disposed in front of the head receiving member 2. Then, while the label sheet C passes between the print head 1 and the head receiving member 2, the label B
At the same time, the printed label B is peeled off from the mount A by bending and guiding the mount A at an acute angle in the traveling direction of the mount A by the peeling member 3, and is fed forward as shown in the figure. It is configured so that only the rear part B' is attached to the mount A when the paper is issued. The label B issued in this manner is removed from the mount A by an operator and affixed to the product.

By the way, in the printing device as described above, when the next label printing operation is performed while the previously issued label B remains above the peeling member 3 as shown in FIG. 11, the peeling member 3 There is a problem in that a plurality of labels accumulate in the vicinity of the label, resulting in a label jam. Therefore, a sensor is provided to detect whether or not the issued label B exists above the peeling member 3, and when the presence of the label is detected by the sensor, the next label issuing operation is stopped. Ru. As shown in FIG. 11, this sensor consists of a pair of emitter 4 and receiver 5, which are placed opposite each other on both sides of label B. The presence of the issued label B is detected by turning off the output signal of the light receiver 5 when the light is blocked. but,
Conventionally, as shown in the figure, a pair of light projector 4 and light receiver 5 were arranged on both sides of label 8, and a gap larger than the width of label B was provided between them. Moreover, as the light receiver 5, a highly accurate one that can function satisfactorily even if the light transmission distance is long is required.

In addition, in this type of printing device, in order to insert the label sheet C between the print head 1 and the head receiving member 2 when installing the label sheet C, the print head 1 is moved in the direction indicated by the arrow X. Although it is possible to swing upward away from the head receiving member 2, in such a configuration, after the print head 1 is swung upward, it must be properly pressed against the head receiving member 2. There is a possibility of neglecting to set the label and performing the next label printing operation. this
In such a case, a blank label is issued and the label is wasted, and if label issue data is being aggregated for such processing results, reissue of the label may cause an error in the aggregation. become. Therefore, in order to prevent such problems, it is necessary to install sensors such as limit switches that detect whether the print head is properly pressed against the head receiving member and stop the label printing operation if the print head is not pressed. Is required.

(Object of the Invention) The first and second inventions of the present application provide a printing device for a label printer that uses only a sensor that uses a pair of light emitting device, light receiving device, and light receiving device with relatively low accuracy to print the above-mentioned labels. The purpose is to prevent issuance errors.

That is, in the first invention, the sensor detects whether or not a published label exists in the peeling part, and in the second invention, the sensor detects whether or not the print head is properly pressed against the head receiving member. The configuration is configured to detect whether or not it is set. With this inexpensive configuration, it is possible to prevent label printing errors such as printing the next label while the previous one remains, or printing a label when the print head is not set correctly. To prevent.

(Structure of the Invention) The first and second inventions of the present application are respectively structured as follows in order to achieve the above object.

First, the first invention is provided with a print head, a head receiving member to which the head is pressed while sandwiching the label sheet, and a head receiving member in front of these, and the printed label on the label sheet can be peeled off from the mount and taken out. In a printing device for a label printer equipped with a peeling member for printing in a state of The sensor includes a light projector and a light receiver provided on the peeling member.

This sensor detects the previously issued label by blocking the detection light between the emitter and receiver, which face each other, when the previously issued label remains on the peeling member without being taken out. Detect presence. In that case, the light emitter or light receiver installed on the print head and the light receiver or light emitter installed on the peeling member are located directly above and below the label, so the light emitter and the light receiver are positioned directly above and below the label. A relatively low-precision device with a short light transmission distance will suffice. Then, when the sensor detects the presence of an already issued label, it is configured to issue an alarm or stop the operation of issuing the next label.

Further, in the second invention, in the configuration in which the print head according to the first invention is able to swing away from the head receiving member, when the print head is correctly set in a state in which it is pressed against the head receiving member, The optical axis of the light projector or light receiver provided next to the front end of the head and the tip of the light receiver or light projector provided next to the peeling member are aligned.

Therefore, according to the second invention, when the print head is not set correctly, the detection light is not input or output between the emitter and the light receiver, and as a result, the print head is not set correctly. is detected. and,
In such a case, the apparatus is configured to issue an alarm or stop the label issuing operation.

(Example) Examples of the present invention will be described below. This embodiment is common to the first and second inventions, and has the features of both inventions at the same time.

First, let me explain the overall configuration of the label printer.
As shown in FIG. 1, the label printer 10 has a label sheet formed by removably pasting a number of labels B... Roll receiving part 13 to which roll D of C is attached
and the label sheet C pulled out from the roll receiving section 13.
The guide rollers 14, 15 that guide the labels B...B on the sheet C are printed with necessary characters, numbers, etc., and the front part of the printed label B is peeled off from the backing paper A to form the main body. Label issuing window 11a provided on the front of case 11
A printing device 16 that prints the paper in a state that it can be taken out from the label, and a mount winding unit 17 that winds up the mount A after the label B has been peeled off.
The configuration includes a motor 19 and the like that drive the winding core 18 and the like in the winding section 17.

Next, the configuration of the printing device 16 will be explained.
6 is a print head 20 and an operation mechanism 21 of the head 20;
, a platen roller 22 to which the front part of the print head 20 is pressed while sandwiching the label sheet C as shown in the figure, and a peeling member 23 having a semicircular cross section disposed immediately in front of the roller 22. . Of these, the platen roller 22, the peeling member 23, and the mount guide shaft 24 disposed below these are installed between the frame 12 and an auxiliary frame 25 fixed to the frame 12. The platen roller 22 is rotationally driven by the motor 19 via a belt (not shown).

Further, the head operating mechanism 21 is shown in FIGS. 1 and 2.3.
As shown in the figure, both side surfaces 26a, 26a and bottom surface 26b
The front view is U-shaped, and both side surfaces 26a, 26
A connecting shaft 27 is installed in the upper part between a and a base member 26 fixed to the frame 12 at one side 26a, and both sides 26a, 26a of the base member 26.
a first support shaft 28 installed in the front part between the first support shaft 28;
A head support member 29 whose rear part is pivotally supported by the front part and whose front part can swing up and down, and a head mounting member whose rear part is also pivotally supported by the first support shaft 28 below the head support member 29. 30 and both sides 268.26a of the base member 26
A second support shaft 31 installed at the rear part between the second support shafts 31 and
The main element is an operating lever 32 which is swingably supported by the control lever 32. The print head 20 is attached to the lower surface of the member 30, and when the head support member 29 is held at the position shown by the solid line in FIG. It is adapted to be pressed against the roller 22.

On the other hand, a latch rod 34 is installed between both sides of an extension part 29a extending rearward from the pivot point of the first support shaft 28 of the head support member 29, and is engaged with both sides of the front part of the operation lever 32. Matching groove 32a.

32a is provided, and both ends 34a, 34a of the latch bar 34 are engaged with the engagement grooves 32a, 32a, respectively. The head 20 is held in pressure contact with the platen roller 22. A pair of left and right tension springs 35.35 are installed between the rear end of the upper surface of the head support member extension 29a and the front part of the operating lever 32, and the operating lever 32 is moved against the springs 35.35. When the latch rod ends 34a, 34a are disengaged from the engagement grooves 32a, 32a by operating as shown by chain lines in FIG. The print head 20 is swung in the Z direction around the first support shaft 28 as shown by the chain line, and the front end of the print head 20 is separated from the platen roller 22.

However, a sensor is attached to the front end of the head support member 29 via a member 36, and a floodlight 3 made of a light emitting diode or the like is attached.
7 is installed facing downward.

Further, the peeling member 23 is provided with a vertical through hole 23a, and the tip end 38a of the optical fiber 38 is inserted into the hole 23a.
is inserted and fixed upward from below, and a light receiver 39 made of a phototransistor or the like is connected to the other end of the optical fiber 38, as shown in FIG. and,
When the front end of the print head 20 is set in pressure contact with the platen roller 22 by the head operating mechanism 21, the projector 37 and the tip 38a of the optical fiber 38 face each other with their optical axes aligned. It has become.

The label printer 10 is integrated into a weight detector, and calculates the weight of the product measured by the detector based on the preset unit price, tare weight, etc. It is configured to calculate the price and print this price, the weight, unit price, etc. mentioned above on the label. Therefore, it has a key manual section for setting the unit price, tare weight, etc., and a display section for displaying the weight, unit price, price, etc. of the product to be weighed, and the weight detector,
A control system including a key input section, a display section, and the printer is configured.

Next, this control system will be explained.

As shown in FIG. 4, this control system is equipped with a microcomputer 40, to which a weight signal a from a weight detector 41 is input via an amplifier 42 and an A-D converter 43. , a key human power signal C from a key human power section 44 is input, and a display signal C is output from the microcomputer 40 to a display section 45. And this microcomputer 4
A print data signal d1, a drive signal e, and an optical axis check signal f are output from 0 to the print head 20, motor 19, and light projector 37 of the label printer 10, respectively, and
A light detection signal g is input from the light receiver 39 of the printer 10 to the microcomputer 40. Here, as shown in FIG. 5, the projector 37 has a light-emitting diode 37a and a resistor 37b arranged in series between the power supply and the ground, and a circuit 370 that bypasses the resistor 37b. The structure includes an analog switch 37d that is closed by a signal (pulse signal). Therefore, the light emitting diode 37a is always turned on, but when the optical axis check signal f is input, the analog switch 37d is closed. When it is closed, the passing current increases and the amount of light emitted is enhanced.The same effect can also be obtained by using the same method to increase the light receiving sensitivity of the light receiver 39 using the optical axis check signal f. Obtainable.

Next, the operation of the above embodiment will be explained according to the flowcharts of FIGS. 6 to 8 showing the operation of the microcomputer 40.

First, in the main program shown in FIG. 6, the microcomputer 40 inputs the weight signal a from the weight detector 41 via the amplifier 42 and the A-D converter 43 in step A1, and the A-D converter 43 inputs the weight signal a. - Determine whether or not the D conversion has been completed. In other words, the A-D converter 43 operates at a nearly constant cycle (for example, 10 to 20 cycles/second).
The signal (analog signal) a' from the amplifier 42 is sampled and converted into a digital signal a'', but even when the weight detector 41 is not loaded with the product to be weighed and even after loading, A-D Until the conversion is completed, the weight values indicated by the weight signals a to a'' are not determined. Therefore,
The microcomputer 40 does not perform steps A4 and subsequent steps until the product to be weighed is loaded and the A-D conversion for the product is completed, and during this time, the microcomputer 40 does not perform steps A2. A3
Performs key check processing. In this key check process, first, in step A2, it is determined whether or not a key operation has been performed based on a key human power signal from the key human power section 44. Then, if any key in the key manual section is O
When N is operated, a predetermined key processing operation is performed in step A3.

Specifically, this key processing operation is performed according to the subprogram shown in FIG. That is, in step B1 of this nap program, it is first determined whether or not the print key provided in the key input section 44 has been turned on. This print key is
This is to interrupt automatic label issuance by the label printer 10 and manually issue a label if necessary, and when the print key is turned on, steps B1 to B2 are executed. Predetermined printing conditions, for example, the operating state of the weight detector 41 determined by the weight signal a is stable, and the detector 41 has a certain weight (
For example, a product weighing 10g or more is loaded, the price calculated from this weight and the unit price or tare weight is within a predetermined digit (for example, 5 digits), and this is not the second printing operation based on the same data, etc. Determine whether the conditions are satisfied. When this condition is satisfied, in step B3, the print data signal d is sent to the print head 20 of the label printer 10, and the drive signal e is sent to the motor 19 to perform the label printing operation, and the above-mentioned printing If the condition is not satisfied, a signal is outputted in step B4 to activate a separately provided miss buzzer.

Further, when the print key is not turned on, steps B1 to Bs' are executed to perform predetermined processing according to the turned-on key.

On the other hand, when the product is loaded on the weight detector 41, when the A-D conversion for the weight signal a is completed,
The microcomputer 40 executes steps A1 to A4 in FIG. 6 and inputs a signal a'' indicating the A-converted weight value, and then performs weighing and display processing in step A5.

In this scale/display process, the operation stability of the weight detector 41 is checked, the output value (signal a'') of the A-D converter 43 is converted into a weight value, and the weight value and the operation of the key manual section 44 are used. Calculation of the price of the product based on the set unit price and tare weight, output of display signal C, flicker prevention processing on the display section 45, automatic zero point correction processing, etc. are performed.

Then, the microcomputer 40
In step A7, it is determined whether or not the above printing conditions are satisfied, and if the conditions are satisfied, the set state of the print head 20 is checked in step A7. In other words, the optical axis check signal [is outputted to the projector 37 shown in FIG. 1.3 or FIG. It is determined whether the light output from the light emitting diode 37a is input to the light receiver 39 by inputting the signal g. In this case, as shown in FIGS. 1 and 3, both ends 34a of the latch rod 34 integral with the head support member 29 are
, 34a are engaged with the engagement grooves 32a, 32a of the operating lever 32, that is, when the print head 20 is correctly held in pressure contact with the platen row 522, the projector 37 attached to the head support member 29 and The tip 38 of the optical fiber 38 attached to the peeling member 23 below
Since the optical axes of a coincide with each other, the detected light from the emitter 37 (light emitting diode 37a) is transmitted through the optical fiber 38 or the receiver 3.
9, and a photodetection signal Q indicating this is input to the photoreceiver 3.
9 to the microcomputer 40. Thereby, the microcomputer 40 confirms that the print head 20 is correctly set. Also, if the print head 20 is not set correctly, that is, both ends 34a of the latch rod and the engagement groove 32a.

32a is not engaged or the engagement is incomplete, a setting error of the print head 20 is detected by not outputting a light detection signal g indicating that the detection light has been received from the light receiver 39. . In that case, the light emitting diode 37
Since the amount of light emitted by a is enhanced, even if a printed label B is present on the peeling member 23 as shown in FIG. 20 set states are confirmed. If the print head 20 is not set correctly, the microcomputer 40 executes steps A7 to 88 above to perform error processing such as displaying the incorrect installation of the print head 20, and also to The operation ends without issuing the .

This prevents a blank label from being issued by a label issuing operation when the print head 20 is not set correctly.

On the other hand, when the print head 20 is correctly pressed and held on the platen roller 22, the microcomputer 40
executes steps A7 to A9 described above, and checks whether there is an issued label B. In this case, since the amount of light emitted from the light emitting diode 37a in the projector 37 is reduced compared to the time of the above-mentioned print rad check, when the previously issued label B is present on the peeling member 23, the amount of light emitted from the light emitting diode 37a is reduced. The detection light from the diode 37a is blocked by the label B and is not input to the optical fiber 38 or the light receiver 39, thereby confirming the presence of the label. In this case, the operation ends without issuing a label. This prevents label clogging caused by issuing the next label while the previously issued label remains on the peeling member 23. On the other hand, if the previously issued label has been taken out by the operator and is not left on the peeling member 23, the detected light is input to the light receiver 39, and a light detection signal g indicating this is sent to the microcomputer. 40, which causes the microcomputer 40 to perform label issuing processing in step A10. In this way, the required labels can be issued without issuing mistakes such as issuing blank labels or label jams.

It should be noted that the label issuing process in step A1o above is specifically performed according to the subprogram shown in FIG.

That is, the microcomputer 40 outputs a drive signal e to the motor 19 in the label printer 10 in step C1, and the motor 19 or the winding core 1 of the liner winding section 17
8 and platen roller 22 to print the label sheet C.
start feeding. Then, in step C2, the presence or absence of a label on the peeling member 23 is checked based on the photodetection signal g from the light receiver 39. In the case of automatic label issuing processing according to the main program shown in FIG. 6, this label check is always performed without a label because it has already been checked in step A9 of the main program. However, the seventh
In the subprogram shown in the figure, when the print key is turned on in step B1 and label issuance processing is performed in step B3 accordingly, that is, when a label is to be issued manually, the previously issued label will be printed on the peeling member 23. Since the presence or absence of the label has not been checked, this check is performed again in step C2 of FIG. 8. And when the last issued label exists,
The microcomputer 40 executes steps C2 to C3 and stops the motor 19 without performing a printing operation. On the other hand, if there is no label on the peeling member 23, including when manually issuing a label, the microcomputer 40 executes steps C2 to C4 to set a predetermined time on the timer, and also performs step C5. , C6 are repeated until the label reaches the peeling member 23 (optical fiber tip 38a) while watching the photodetection signal from the light receiver 39. In this case, if the predetermined time elapses before the label arrives, this means that the initial position of the label has shifted, so the microcomputer 40 executes steps C6, C7, and C3, and the writing error occurs. is displayed, and then the motor 19 is stopped. Then, only when the arrival of the label is detected before the predetermined time elapses, step C8 is executed, printing is performed on the label, and the motor 19 is stopped in step C3.

Next, another example of the operation of the microcomputer 40 whose main program flowchart is shown in FIG. 9 will be described. Note that this example is for a case where no operation is performed to increase the amount of light emitted from the light emitting diode 37a in the light projector 37 during the print head check process.

The microcomputer 40 first resets the label flag in step D1, and then waits for the completion of the A/D conversion of the signal a by the A/D converter 43 in step D2. If no product is loaded on the weight detector 41 or if the product has just been loaded and the A-D conversion has not yet been completed, a label check is performed from step D2 to step D3 described above. This label check is to detect whether or not a previously issued label exists on the peeling member 23 using the optical detection signal Q from the light receiver 39, as in the operation example described above. Since it is not, the label flag is reset in step D4. However, the flag has been reset in advance in step D1. Then, according to steps Ds and De, a key check process similar to the above operation example is performed.

On the other hand, when the product is loaded on the weight detector 41 and the A-D conversion is completed, the microcomputer 40 performs step D.
According to γ, Da, and D9, weight value input, scale/display processing, and printing conditions are confirmed in the same manner as in the operation example, and if the printing conditions are satisfied, a label check is performed in step D1o.

This label check is also performed using the photodetection signal g from the photoreceiver 39, as in step D3 above, and the photoreceiver 39
It is determined that the previously issued label is present on the peeling member 23 when no detection light is input. Since the optical axes of the optical fiber tip 37 and the optical fiber tip 38a do not match, the optical receiver 39
Since no detection light is input to the label, it is determined that there is a label.

If it is determined in this step D+o that there is a label, the microcomputer 40 then proceeds to step D1.
The label flag is checked in step 1, but if it is determined that there is a label at the beginning of work, it means that the print head is not set correctly, and the label flag was reset in step D4 above, so in this case , step 12 is executed to perform error processing indicating a missetting of the print head 20. On the other hand, if it is determined in step D1o that there is no label, this means that there is no previously issued label on the peeling member 23 and the print head 20 is correctly set, so the microcomputer 40 detects the label in step D13. issuance processing is performed, and then a label flag is set in step D14.

Then, before the A-D conversion for the next product is completed, the microcomputer 40 executes steps D2 to D3 above and performs a label check, but in this case, the previously issued label is peeled off by the worker. If it has been taken out from above the member 23, steps D3 and D4 are executed to reset the label flag. Then, like last time, step 05.06 and D7 to D14
Accordingly, if the print head 20 is set correctly, a label is issued, and if the print head 20 is not set correctly, no label is issued, and error processing is performed in step D12.

On the other hand, if the previously issued label remains on the peeling member 23, the label flag is kept set because the process moves to the following steps without executing steps D3 and D4. Therefore, when the A-D conversion is completed and step D1o is executed through steps D7 to D9, it is determined that there is a label, and step D11 is further executed, the microcomputer 40 executes step D12 because the label flag is set. Terminates the operation without executing. In other words, in this case, label issuance is stopped without performing the error processing indicating a print head setting error in step D12.

In this way, the presence of the issued label on the peeling member 23 and the setting error of the print head 20 are detected by the sensor consisting of the pair of light emitter 37 and light receiver 39,
Issuance of labels under such conditions will be prevented.

In this example of operation, the label issuing process in step D13 is specifically performed according to the subprogram shown in FIG. 10. This subprogram is the label issuing process subprogram (eighth
In the same way as in Figure), first operate the motor 19 in step E1, and after confirming that there is no label on the peeling member 23 when manually issuing a label in step E2, follow steps E3 to E7. If the label reaches the peeling member 23 (optical fiber tip 38a) before a predetermined time elapses from the start of operation of the motor 19, printing is performed on the label, and then the motor 19 is stopped. If the label has not arrived even after the predetermined time has elapsed, steps Ea and Ey are executed from step E5 to handle the writing error, and then the motor 19 is stopped. On the other hand, in the case of manually issuing a label, if it is determined in step E2 that a label is present, the label flag is checked in step E9. When the flag is set, that is, when the previously issued label remains on the peeling member 23, step E2 is repeatedly executed without stopping the motor 19, and the previously issued label is sent out as is. At the same time, when the gap with the next label reaches above the peeling member 23 (optical fiber tip 38a) and it is determined that there is no label, steps E3 to E are performed.
Execute step 8. Further, if the label flag is reset, this means that the print head 20 is not set correctly, so step E9 to step E
7 and immediately stop the motor 19.

Here, in the above embodiment, the light emitter 37 was attached to the front end of the print head 20, and the light receiver 39 was connected to the end of the optical fiber 38. action takes place.

Alternatively, the tip of the optical fiber may also be exposed to the front end of the print head, and a light emitter or a light receiver may be provided at the other end. Furthermore, the light emitting surface of the light emitter or the light receiving surface of the light receiver may be made to directly face the peeling member without using an optical fiber.

(Effects of the Invention) As described above, according to the present invention, in a printing device for a label printer that issues printed labels in a removable state, a relatively low-precision light projector with a short light transmission distance is used. A sensor consisting of a sensor and a light receiver checks whether the issued label has been taken out or not taken out and remains on the peeling member, and also whether the print head is in pressure contact with the head receiving member. A check will be made to see if it is set correctly. This makes it possible to prevent label issuance errors such as label jams and issuance of blank labels with an inexpensive configuration.

[Brief explanation of the drawing]

Figures 1 to 10 show the present cylinder 1. This shows a common embodiment of the second invention, in which Fig. 1 is a longitudinal side view showing the configuration of a label printer, Fig. 2 is an enlarged plan view of a printing device in the printer, and Fig. 3 is Fig. 2 - ■Longitudinal side view of the printing device cut along the line, Figure 4 is a block diagram showing the control system, Figure 5
The figure is a circuit diagram showing an example of the circuit configuration of a projector, and Figure 6 is a circuit diagram showing an example of the circuit configuration of a projector.
7.8 is a flowchart of the subprogram in the operation example, FIG. 9 is a flowchart of the main program showing the second operation example, and FIG. 10 is the flowchart of the subprogram in the operation example. It is a flowchart figure of a subprogram. FIG. 11 is a perspective view of essential parts showing a conventional example. 10... Label printer, 20... Print head, 2
2...Head receiving member (platen roller), 23...
- Peeling member, 37... Emitter, 39... Light receiver, A
...Paper, B...Label, C...Label sheet. Applicant: Ishida Kouki Seisakusho Co., Ltd. Figure 2 Figure 3 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (4)

[Claims] (1) It has a print head, a head receiving member to which the head is pressed while sandwiching a label sheet, and a peeling member placed in front of these members, and the label printed by the print head is attached to the backing paper of the label sheet. A printing device for a label printer that prints in a state that can be peeled off and taken out from the print head, the printing head having either a light emitter or a light receiver installed on the front end of the print head, and a tip facing the light emitter or light receiver. The present invention is characterized in that the peeling member is provided with the other of a light emitter and a light receiver installed on the peeling member, and these constitute a sensor for detecting whether or not an issued label is present on the peeling member. Label printer printing device. (2) Printing in the label printer according to claim 1, wherein the sensor outputs a signal to stop the next label issuing operation when detecting the presence of a published label on the peeling member. Device. (3) It has a print head, a head receiving member to which the head is pressed while sandwiching the label sheet, and a peeling member disposed in front of these members, and the label printed by the print head is attached to the mount of the label sheet. A printing device for a label printer, in which the print head is issued in a state where it can be peeled off and taken out, and the print head is swingable so as to separate from the head receiving member, and the print head is provided on the front end of the print head. Either one of the emitter or the receiver, and the emitter or the receiver, the tip of which is provided on the peeling member so that the optical axis is aligned with the emitter or receiver when the print head is pressed against the head receiving member. 1. A printing device for a label printer, comprising: a sensor for detecting whether or not a print head is held in pressure contact with a head receiving member; (4) The printing device of the label printer according to claim 3, wherein the sensor outputs a signal to stop the label issuing operation when detecting that the print head is not held in pressure contact with the head receiving member. .