JPH05286162A - Method and apparatus for recording - Google Patents

Abstract

PURPOSE:To keep recording density constant at all times regardless of the temperature of a recording head by changing the number of times to energize the recording head and the duration of energization in accordance with the temperature of the recording head. CONSTITUTION:Recording is made by controlling the number of times to energize a thermal head 13 and the duration of energization in accordance with the temperature of the thermal head 13 detected by a temperature sensor 133 that detects the temperature of the thermal head 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method and apparatus for recording an image on a recording medium using a thermal recording head.

[0002]

2. Description of the Related Art Heretofore, a thermal printer has been known in which a thermal head is energized for recording, and such a thermal printer is generally a thermal printer equipped with a line type thermal head for recording in line units. Is. There is known a method of energizing the same heating resistor by applying a predetermined voltage a predetermined number of times at a certain time interval when recording information of one line with this thermal printer. This is to eliminate the variation in the recording density due to the temperature of the heating resistor of the thermal head and to obtain a more stable recording density. In such a recording process, a method has been proposed in which the temperature of the thermal head is prevented from rising by keeping the number of times the thermal head is energized and changing the energization time once according to the temperature of the thermal head. ..

[0003]

As described above, in the above-mentioned conventional example, the number of times of energization during one line recording is constant regardless of the temperature of the thermal head, so that the energization time of one time is restricted. That is, for example, the recording density tends to be too low at an extremely low temperature, but there is a problem that sufficient recording density cannot be obtained only by increasing the time for energizing the thermal head to increase the applied energy. ..

The present invention has been made in view of the above conventional example, and is always stable regardless of the temperature of the recording head by changing the number of times the recording head is energized and the energization time according to the temperature of the recording head. An object of the present invention is to provide a recording method and apparatus capable of obtaining a recording density.

[0005]

In order to achieve the above object, the recording apparatus of the present invention has the following constitution. That is,
A recording apparatus for recording an image on a recording medium by a thermal recording head, wherein temperature detecting means for detecting a temperature of the thermal recording head and energizing the thermal recording head a plurality of times to drive the thermal recording head. Drive means for performing one-line recording, and control means for controlling the number of energizations and the energization time by the drive means according to the temperature detected by the temperature detection means.

In order to achieve the above object, the recording method of the present invention has the following configuration. That is, it is a recording method for recording an image on a recording medium by energizing the thermal recording head a plurality of times to perform recording of one line, and a step of detecting the temperature of the thermal recording head and the detected temperature. When the temperature of the thermal recording head is equal to or lower than a predetermined value, the number of times of energizing the thermal recording head is reduced and one energization time is lengthened to perform recording as compared with the case where the temperature exceeds the predetermined value. ..

[0007]

In the above construction, the number of energizations and the energization time for energizing the thermal recording head are controlled according to the temperature detected by the temperature detecting means for detecting the temperature of the thermal recording head.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a view showing the schematic arrangement of the thermal printer of this embodiment and the electrical connection between the control unit 101 and the recording unit 102.

In FIG. 1, the thermal head 13 is a line head having a heating resistor for one line. The thermal head 13 inputs a serial recording data 43a for one line from the control unit 101 in synchronization with a shift clock 43b, a shift register 130, and a latch signal 44.
Thus, a latch circuit 131 for latching the recording data for one line held in the shift register 130 and a heating element 132 including a heating resistor for one line are provided. Here, the heating resistors 132 are 132-1 to 132-
It is divided into m blocks up to m and driven for heat generation. Further, 133 is a temperature sensor for detecting the temperature of the thermal head 13. The output signal 42 of the temperature sensor 133 is A / D converted in the control unit 101, and the control unit 101 detects the temperature of the thermal head 13 by the A / D converted digital value. In the present embodiment, the temperature information is A / D converted into 256 steps of 0 to 255, and the pulse width of the strobe signal 47 and the number of pulses applied to the thermal head 13 (the number of scans) corresponding to the temperature of each step. ) Is changed and the thermal head 1
The applied energy to 3 is changed.

Reference numeral 45 denotes a motor driver circuit, which is a control unit 10.
According to the instruction No. 1, the paper feeding motor 48 and the cutter driving motor 49 for cutting the recording paper are rotationally driven.
Reference numeral 46 denotes a drive circuit for energizing the heat-producing low antibody of the thermal head 13 to drive the heat generation. The drive circuit 46 can drive the heat generation by changing the energizing pulse width or the energizing voltage according to an instruction from the control unit 101. Reference numeral 110 denotes a line memory that stores print data for one line. 113 is a CPU, and ROM1
The entire control unit 101 is controlled in accordance with the control program and various data stored in 14. 115 is a CPU
It is used as a work area 113 and temporarily stores various data. 116 is a timer, CPU113
When the clocking of the time designated by the instruction is started and the clocking is ended (timed out), the CPU 113 is notified that the time has passed by an interrupt or the like.

Next, the recording process for one line in the thermal printer of this embodiment will be described with reference to FIG. The control program for executing this processing is the control unit 101.
It is stored in the ROM 114.

This process is started in the state where the recording data for one line to be recorded is stored in the line memory 110, and first, at step S1, the data for one line is serially transferred to the shift register 130 of the thermal head 13. To do. When the data transfer for one line is completed, the latch signal 44 is output in step S2, and the record data for one line held in the shift register 130 is stored in the latch circuit 131. Next, in step S3, the temperature information of the thermal head 13 detected by the temperature sensor 133 is input through the signal 42.

In this embodiment, as described above, the temperature information from the thermal head 13 is divided into 256 levels of 0 to 255. If the value of this temperature information is "63" or less, the process proceeds to step S5, and the number of scans is set. The timer 116 is set to "4" with the time for applying the voltage to the thermal head 13 set to 2t. On the other hand, when the value of the temperature information is "64" or more, the process proceeds to step S4, the number of scans is "8", and the set time to the timer 116 to determine the voltage application time to the thermal head 13 is set to t. In this embodiment, two types of time settings and the number of scans are set according to the temperature of the thermal head 13, but the present invention is not limited to this, and for finer temperature information. The setting value may be changed more finely.

When the number of scans and the voltage application time are set in this way, the process proceeds to step S6, and the thermal head 13
The heat generating resistor 132-1 of the heat generating resistor 132 is energized to record an image. In this way, the process waits until the time set in the timer 116 elapses, and it is checked in step S7 whether power supply to all blocks (4 blocks in this embodiment) of the heating resistors is completed. If power supply to all blocks has not been completed in step S7, the process proceeds to step S8, and power is supplied to the next block of the heating resistor in the same manner. Thus, in step S7, all the heating resistors (132-1 to 132-
When the heat generation driving in 4) is completed, the process proceeds to step S9, and the number of scans set in step S4 or step S5 is reduced by one. Next, the process proceeds to step S10, and it is determined whether or not the scans for the number of scans set in step S4 or step S5 have been completed. If the set number of scans have not been completed, step S
6, the heating resistor 132-1 is energized in the same manner as described above, and the above-described operation is repeated. Thus step S
In 10, when the scan process for the set number of scans is completed, the recording process for one line is completed.

FIG. 3 is a timing chart showing the recording timing of one line in the thermal printer of this embodiment.

In FIG. 3, FIG. 3A is the same as FIG.
FIG. 9 is a diagram showing the recording timing of one line according to the pulse width (t) and the number of scans (8) set in step S4 of FIG.

FIG. 3B is a diagram showing the recording timing of one line according to the pulse width (2t) and the number of scans (4) set in step S5 of FIG. Note that each of the strobes 1 to 4 has a heating resistor 1
The strobe signal (energization signal) output to each of 32-1 to 132-4 is shown.

As described above, according to the present embodiment, when the temperature of the thermal head is low, the number of scans is reduced, the pulse width of the energizing pulse is lengthened and the energizing time is lengthened, so that the time required for recording one line is reduced. It is possible to secure the recording density without extending the recording density.

As a result, in a facsimile machine, for example, the time that can be used for recording one line is limited by the minimum transmission time, so such an operation is effective for making the recording density uniform.

In the above embodiment, the thermal head 1 is used.
The number of scans and the voltage application time (pulse width of strobe signal) were set by the temperature of No. 3, but the present invention is not limited to this, and after the recording of one line is started, the recording of the next line is started. Alternatively, the number of scans and the voltage application time may be set according to the elapsed time.

This is because, for example, when the sensitivity of the temperature sensor 133 is low, it is judged that the time interval until recording of the next line is long, the temperature of the thermal head 13 is low, and the number of scans or The voltage application time is changed.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. It goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program for implementing the present invention to a system or an apparatus.

[0024]

As described above, according to the present invention, the number of times the recording head is energized and the energization time are changed according to the temperature of the recording head, so that stable recording is always performed regardless of the temperature of the recording head. There is an effect that the concentration can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a thermal printer of an embodiment and an electrical connection between a control unit and a recording unit.

FIG. 2 is a flowchart showing a recording process in the thermal printer of the embodiment.

FIG. 3 is a timing chart showing the timing of energizing the thermal head in the recording process of the thermal printer of the embodiment.

[Explanation of symbols]

 45 Motor Driver Circuit 46 Thermal Head Drive Circuit 48 Paper Feed Motor 101 Control Unit 102 Recording Unit 110 Line Memory 113 CPU 114 ROM 115 RAM 116 Timer 130 Shift Register 131 Latch Circuit 132 Heating Resistor 133 Temperature Sensor

Claims (3)

[Claims] 1. A recording apparatus for recording an image on a recording medium by a thermal recording head, comprising: temperature detecting means for detecting a temperature of the thermal recording head; Drive means for driving the recording head to perform one-line recording, and control means for controlling the number of energizations and energization time by the drive means according to the temperature detected by the temperature detection means. Recording device. 2. When the temperature of the thermal recording head is equal to or lower than a predetermined value, the control means reduces the number of times the thermal recording head is energized to reduce one energization time as compared with the case where the temperature exceeds the predetermined value. The recording apparatus according to claim 1, wherein the recording apparatus is controlled to be long. 3. A recording method for recording an image on a recording medium by energizing a thermal recording head a plurality of times to record one line, the step of detecting the temperature of the thermal recording head, When the detected temperature of the thermal recording head is equal to or lower than a predetermined value, recording is performed by reducing the number of times of energizing the thermal recording head and lengthening one energization time as compared with the case of exceeding the predetermined value. And a recording method comprising: