JPH0585644U - Print density controller for thermal printer - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a print density control device 10 for a thermal printer that can adjust the print density even by the ambient temperature and can suppress the influence of the change in the print density due to the ambient temperature. Constituting the temperature itself of the environment surrounding the thermal printer 11 in the control, a print density control device for a thermal printer having a thermal print head 2 and a printing mechanism 18 having a platen 17, which is a thermal printer. 11 is provided in the printer frame 12, and an environmental temperature sensor 28 that detects the environmental temperature around the thermal printer 11 and a control that controls the energy supplied to the heating element of the thermal print head 2 by the temperature signal from the environmental temperature sensor 28 And a circuit 29.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a print density control device for a thermal printer, and more particularly to a print density control device for a thermal printer that takes environmental temperature into consideration.

[0002]

[Prior Art]

 Conventionally, the printing method of a thermal printer has been a thermal transfer method in which a belt-shaped carbon ribbon for thermal transfer is used to perform thermal transfer to a print medium made of ordinary high-quality paper, or the print medium itself coated with a thermochromic agent layer is heated. There is a heat coloring method that causes the color to develop.

Further, as the print medium, there is a label continuum in which a plurality of label pieces are temporarily attached on a strip-shaped mount, or a tag continuum without an adhesive layer.

In any of these systems, such a thermal printer is equipped with a thermal print head that applies heat to the print medium.

In this thermal print head, a large number of heating elements composed of electric resistors are arranged in parallel, and a current of a predetermined energy is supplied to the heating elements to generate heat, thereby performing thermal printing.

The temperature of the thermal print head (the temperature of the support of the heating element) is detected and feedback control is performed to maintain an appropriate heat generation temperature and adjust the print density within a predetermined range.

In particular, when printing a bar code or other optically readable characters as print information, the control of the heat generation temperature, that is, the control of the print density has a great influence on the performance of the printer.

A conventional print density control device will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic view of a main part of a general print density control device 1 of a conventional thermal printer. The print density control device 1 includes a head temperature sensor 3 for detecting the temperature of a thermal print head 2. It has a control circuit 4 which outputs a control signal in response to a temperature signal from the head temperature sensor 3, and a head drive circuit 5 which supplies printing energy to the thermal print head 2 in response to the control signal from the control circuit 4.

The drive signal from the head drive circuit 5 causes the heat generating element 6 of the thermal print head 2 to generate heat, and prints certain information on the print medium, for example, the thermal label 7, as it is transferred.

In addition to the thermal label 7, a carbon ribbon (not shown) for thermal transfer is used to perform thermal transfer on the print medium to perform printing.

The adjustment of the printing energy is to change and control the pulse width to the heating element 6 of the thermal printing head 2 as shown in FIG. 4, for example.

Alternatively, depending on the thermal printer, the pulse height may be changed.

Thus, the installation environment temperature of the thermal printer is set to, for example, 5 to 35 ° C., and the temperature of the thermal print head 2 is detected and controlled so as to keep this head temperature constant. The color development state of the thermal transfer and thermal label 7 is affected not only by the thermal print head 2 but also by the surrounding environmental temperature, and the print density may change even within the above temperature range.

For example, in a cold season or a cold place, since the thermal label or the carbon ribbon itself is cold, even if the thermal print head 2 is controlled to an appropriate temperature, sufficient printing energy is not supplied and print density is reduced. There is a problem that becomes thin.

On the contrary, in a warm season or a warm place, there is a problem that the print density is increased.

Particularly in recent years, the number of cases where printing operations are performed in a high temperature or low temperature environment is increasing, or even in the early morning of the day, the thermal label 7 or the carbon ribbon itself is still cold and the thermal print head 2 is Depending on the heat generation, the proper print density may not be obtained.

As described above, there is a problem that the print density controlled by the thermal print head 2 kept at a constant temperature changes depending on the ambient temperature.

[0018]

[Problems to be solved by the device]

 The present invention has been made in consideration of the above problems, and it is possible to adjust the print density depending on the environmental temperature and to suppress the influence of the change in the print density due to the environmental temperature. The challenge is to provide

[0019]

[Means for Solving the Problems]

 That is, the present invention focuses on incorporating the temperature itself of the environment surrounding the thermal printer into the control, and printing of a thermal printer having a printing mechanism having a thermal printing head and a platen for printing predetermined information on a printing medium. A density control device, which is installed in the printer frame of the thermal printer, and which detects the environmental temperature around the thermal printer and the temperature signal from the environmental temperature sensor that causes the thermal print head to generate heat. A print density control device for a thermal printer, comprising: a control circuit for controlling energy supplied to the element.

The ambient temperature sensor may be provided at an appropriate position on the printer frame, but is preferably a thermal label or a tag such as a thermal label or tag that is likely to directly affect the print density together with the thermal print head. A position that can detect the environmental temperature around the print medium or the print medium such as carbon ribbon is desirable.

[0021]

[Action]

 In the print density control device of the thermal printer according to the present invention, by detecting the ambient temperature and incorporating this in the drive control of the thermal print head, the pulse width to the thermal print head can be adjusted according to the change of the ambient temperature. It is possible to control the supplied energy for printing by changing the temperature, and it is possible to keep the print density constant without being affected by the change in environmental temperature.

[0022]

【Example】

 Next, a print density control device 10 for a thermal printer according to an embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIGS. 3 and 4 are designated by the same reference numerals, and the detailed description thereof will be omitted.

FIG. 1 is an overall schematic view of a thermal printer 11 equipped with a print density control device 10. The thermal printer 11 includes a printer frame 12 and a large number of label pieces 14 on a strip-shaped mount 13. A supply shaft 16 for the label continuous body 15 (medium to be printed) temporarily attached, a printing mechanism 18 having the thermal print head 2 and a platen 17, a peeling mechanism 20 having a peeling plate 19, a mount take-up shaft 21, A carbon ribbon supply shaft 23 of the carbon ribbon 22 for thermal transfer, a carbon ribbon winding shaft 24, a rotation drive motor 25, a sensor 26 of the label continuum 15, a sensor 27 of the carbon ribbon 22, and an environmental temperature sensor 28. , A control circuit 29, and the head drive circuit 5.

The print density control device 10 comprises an environmental temperature sensor 28, a control circuit 29, and a head drive circuit 5.

By the rotation drive motor 25, the label continuum 15 is supplied from the supply shaft 16 of the label continuum 15 and the carbon ribbon 22 for thermal transfer is supplied from the carbon ribbon supply shaft 23, and further to the thermal print head 2. Predetermined printing is performed on the label piece 14 of the mount 13 by supplying the print signal.

In the printed label continuum 15, only the mount 13 turns rearward at the peeling plate 19, and the label piece 14 is peeled from the mount 13.

The backing paper 13 from which the label pieces 14 have been peeled off is taken up by the backing paper take-up shaft 21, and the carbon ribbon 22 for thermal transfer is taken up by the carbon ribbon take-up shaft 24.

The ambient temperature sensor 28 is configured by a thermistor or the like, and outputs its temperature signal to the control circuit 29.

The ambient temperature sensor 28 can be installed on the printer frame 12 as close as possible to the supply shaft 16 of the label continuum 15 and the carbon ribbon supply shaft 23 of the carbon ribbon 22 to detect the ambient temperature around it. By this, the influence of the ambient temperature can be reflected more accurately in the print density control.

The control circuit 29 determines the level of the temperature signal and outputs a drive control signal to the head drive circuit 5.

The drive control signal may be set in a linear manner, for example, in a stepwise manner such as 0-10 ° C, 11-20 ° C, 21-30 ° C, 31 ° C or higher. This may be set and the supply pulse width at each stage may be changed.

The head drive circuit 5 supplies a print pulse of predetermined energy to the thermal print head 2 in response to a drive control signal from the control circuit 29.

The print density control operation will be described with reference to the flowchart of FIG.

First, in step S 1, the control circuit 29 reads the environmental temperature from the environmental temperature sensor 28.

In step S2, it is determined whether or not this environmental temperature is within the reference temperature.

The lower limit temperature and the upper limit temperature of the reference temperature can be arbitrarily set, and are selected in particular according to the usage environment of the thermal printer 11, the types of the label continuum 15 and the carbon ribbon 22, and the like. And

If the temperature deviates from the reference temperature, it is judged that the print density control based on the ambient temperature is necessary, and the print density is adjusted in step S3.

Specifically, the print pulse width and the like are changed, and the head drive circuit 5 supplies printing energy to the thermal print head 2 to perform printing in step S4.

If the ambient temperature is within the reference temperature, the same printing operation as usual is performed in step S4.

In the present invention, a plurality of environmental temperature sensors may be provided and the print density may be controlled by the combination of these detection signals.

[0041]

[Effect of the device]

 As described above, according to the present invention, since the environmental temperature sensor and the control circuit are provided in the print density control device of the thermal printer, even if the environmental temperature changes, the print density can be adjusted according to the environmental temperature. The print density can be adjusted, and a stable print density can always be maintained as a thermal printer.

[0042]

[Brief description of drawings]

FIG. 1 is a print density control device 10 according to an embodiment of the present invention.
1 is an overall schematic view of a thermal printer 11 equipped with.

FIG. 2 is a flowchart diagram for explaining a print density control operation of the same.

FIG. 3 is a schematic explanatory diagram of a print density control device 1 in a conventional thermal print head 2.

FIG. 4 is an explanatory diagram of a print pulse width of the same.

[Explanation of symbols]

 1 Printing Density Control Device 2 Thermal Printing Head 3 Head Temperature Sensor 4 Control Circuit 5 Head Driving Circuit 6 Heating Element 7 Thermal Label (Printing Medium) 10 Printing Density Control Device of Thermal Printer 11 11 Thermal Printer 12 Printer Frame 13 Belt-shaped Mount 14 Label Pieces 15 Label Continuum (Media to be Printed) 16 Supply Shaft of Label Continuum 15 17 Platen 18 Printing Mechanism 19 Peeling Plate 20 Peeling Mechanism 21 Mount Paper Winding Shaft 22 Carbon Ribbon (Printing Medium) 23 for Thermal Transfer Carbon Carbon Supply Shaft 24 Carbon Ribbon Winding Shaft 25 Rotation Drive Motor 26 Sensor for Label Continuum 15 27 Carbon Ribbon 22 Sensor 28 Environmental Temperature Sensor 29 Control Circuit S1-S4 Each Step of Print Density Control Operation

Claims (1)

[Scope of utility model registration request] 1. A print density control device for a thermal printer having a printing mechanism having a thermal print head and a platen for printing predetermined information on a print medium, the print density control device being provided in a printer frame of the thermal printer, An environmental temperature sensor that detects an environmental temperature around the thermal printer; and a control circuit that controls energy supplied to a heating element of the thermal print head by a temperature signal from the environmental temperature sensor. Print density control device.