JP2575130B2 - Printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer using thermal energy, such as a thermal printer, and more particularly, to an electrical energy for selectively generating heat from a plurality of heating elements of a print head. Is provided, whereby the recording is performed.

2. Description of the Related Art Conventionally, in a printer using a print head in which a heating element that generates heat by supplying energy, for example, a thermal printer, recording is performed by a thermal head. Therefore, it is necessary to control the electric energy supplied to the heating elements of the thermal head according to the temperature of the thermal head. Therefore, generally, means for detecting the temperature is provided in the printer.

[Problems to be solved by the invention] However, in such a thermal printer,
The above-mentioned temperature detection sensor cannot be placed close to the thermal head, but is usually placed at an appropriate position in the printer case. There is a difference between the temperature of the thermal head and the temperature of the thermal head, for example, because many bodies are arranged. That is, when the power is turned on to the printer, the temperature inside the printer rises with the passage of time, but the temperature where the temperature detecting sensor is disposed tends to gradually increase from the temperature near the thermal head. is there. Therefore, when recording is performed based on information from the sensor, there is a problem that an appropriate density is not maintained and the density changes.

SUMMARY OF THE INVENTION In view of the above-described conventional problems, it is an object of the present invention to correct the temperature information from the temperature detecting means so as to approach the actual temperature of the print head in accordance with the lapse of time after power-on, and to use the corrected temperature to correct the temperature information. An object of the present invention is to provide a printer capable of preventing the occurrence of shading in recording due to the influence of time by controlling the print head.

[Means for Solving the Problems] A printer according to the present invention is a printer that prints on a printing material using a printhead having a heating element that generates heat in accordance with supplied energy, wherein Are temperature detecting means provided at different positions, time measuring means for measuring an elapsed time after the power of the printer is turned on, and a temperature from the temperature detecting means in accordance with a length of time elapsed by the time measuring means. A temperature information correcting means for correcting information, and a control means for controlling energy supplied to the print head based on the temperature information corrected by the temperature information correcting means are provided.

In this case, the temperature information correction means may subtract a temperature difference corresponding to the elapsed time measured by the time measurement means from the temperature information by the temperature detection means.

(Operation)

According to the present invention, after turning on the power of the printer, the temperature detecting means detects the temperature at a position different from the print head,
The timer measures the elapsed time after the power is turned on. The temperature information correcting means corrects the temperature information detected by the temperature detecting means according to the length of the elapsed time measured by the time measuring means. For example, the temperature difference may be corrected by subtracting the temperature difference corresponding to the elapsed time measured by the time measuring means from the temperature information by the temperature detecting means.

The control device controls the energy supplied to the print head based on the temperature information corrected by the temperature information correction means, and makes the print density on the printing material constant.

[Example] Hereinafter, an example of the present invention will be described in detail and specifically with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Here, reference numeral 1 denotes a thermal head for performing recording on a recording material such as thermal paper by heat or thermal transfer, and has a plurality of heating elements (not shown) to which a predetermined power supply voltage is applied from a voltage generating circuit 2. Then, heat is selectively generated. Reference numeral 3 denotes a drive pulse generating circuit for supplying a drive pulse signal to the thermal head 1, and the heat generating element can cause the heating element to selectively generate heat by the drive pulse signal. By the way, the drive pulse signal is controlled and controlled by the temperature judgment circuit 4 depending on the temperature of the thermal head 1. The temperature judgment circuit 4 has a CPU function. , And the elapsed time after the power is turned on from the timer 6 are input.

FIG. 2 shows an example of the relative position between the above-mentioned thermal head 1 and the thermistor 5, where 7 is a platen for holding a thermal paper (not shown), and 8 is along the platen 7 with the thermal head 1 mounted. In the carriage which moves in parallel, the thermistor 5 is fixedly disposed at a position different from that of the thermal head 1. Therefore, as in the conventional case, the ambient temperature differs between the vicinity of the thermal head 1 and the thermistor 5 as described above.

FIG. 3 shows a state in which such a temperature difference increases with the elapse of time after the power is turned on. T1 indicated by a solid line indicates the ambient temperature near the thermal head 1 and T2 indicated by a broken line indicates the increasing tendency of the ambient temperature near the thermistor 5. Show. FIG. 4 shows the tendency of the temperature difference between them. In other words, the temperature T2 detected by the thermistor 5 has a greater increase over time than the temperature T1 near the thermal head. Therefore, if the thermal head drive pulse is controlled in accordance with the temperature detected from the thermistor 5, it is corrected. In this example, only the temperature difference shown in FIG. 4 is to be corrected in the temperature judgment circuit 4 because the recording tends to become thinner with time.

FIG. 5 shows a sequence of the series of control operations. First, when the power of the thermal printer is turned on, the timer 6 is set in step S1, then the temperature information from the thermistor 5 is obtained in step S2, and in step S3, From the temperature information and the elapsed time obtained from the timer 6, a fourth
The temperature information is corrected with reference to the diagram shown in FIG. Next, it is determined whether or not recording is performed in step S4, and steps S2 to S4 are repeated until the recording is performed.If it is determined that the recording is performed, the process proceeds to step S5 to change the drive pulse according to the corrected time. Then, the pulse changed in step S6 is supplied to the thermal head to perform recording.

In the above description, the case where the energizing time of the drive pulse is changed according to the corrected temperature has been described. However, the present invention is not limited to this, and electric energy such as applied voltage and current is detected by a detection signal from the temperature detecting means. It is needless to say that the present invention can be widely applied to a printer that is controlled in accordance with the printer.

[Effects of the Invention] As described above, according to the present invention, the temperature information obtained from the temperature detecting means is corrected in accordance with the elapsed time after power-on obtained from the clock means, and the corrected temperature information is corrected. The control means controls the energy supplied to the print head in accordance with the above, so that correct temperature information in the vicinity of the print head can be reflected, and the print density does not change due to the elapsed time after the power is turned on. Is now available.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a configuration of a control circuit of the printer of the present invention, FIG. 2 is a schematic diagram for explaining a relative position between the thermal head and a temperature detecting means, and FIG. FIG. 4 is a characteristic curve diagram showing a time difference between the temperature and the temperature detecting means, FIG. 4 is a characteristic curve diagram of the temperature difference, and FIG. 5 is a flowchart showing a control operation procedure according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Thermal head, 2 ... Voltage generation circuit, 3 ... Drive pulse generation circuit, 4 ... Temperature judgment circuit, 5 ... Thermistor, 6 ... Timer.

Claims (2)

(57) [Claims] 1. A printer for printing on a printing material using a print head having a heating element that generates heat in accordance with supplied energy, comprising: a temperature detection unit provided at a position different from the print head. A time measuring means for measuring an elapsed time after turning on the power of the printer; a temperature information correcting means for correcting temperature information from the temperature detecting means according to a length of the elapsed time measured by the time measuring means; A control unit for controlling energy supplied to the print head based on the temperature information corrected by the temperature information correction unit. 2. The temperature information correcting means according to claim 1, wherein said temperature information correcting means subtracts a temperature difference corresponding to an elapsed time measured by said time measuring means from temperature information obtained by said temperature detecting means. Printer according to.