JPS618365A - Transfer type thermal recorder - Google Patents

Abstract

PURPOSE:To prevent uneven density of a record image due to scatters of resistance values in a heating resistor, by determining the energizing time of the heating resistor from the resistance values thereof obtained from recording density to drive a thermal head. CONSTITUTION:A recording paper 10 printed experimentally is read out with an optical sensor 11 and the recording density by heating resistors is computed with a recording density computing circuit 12. The resistance values of the heating resistors are calculated with a resistance value computing circuit 13 from this recording density. A printing energy computing circuit 14 determines the energization time according to the resistance values of the heating resistors. A thermal head driving circuit 15 determines the heat resistor to be energized based on recording information to control the energization time according to the time determined by the printing energy computing circuit 14. With such an arrangement, heat energy working on a hot melting ink is produced equally from the heating resistors in the generation of heat therefrom to make the recording density uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transfer-type thermal recording device that is designed to prevent density unevenness in recorded images caused by variations in the resistance value of a resistance heating element of a thermal head.

[Useless technology]

One example of a conventional transfer type thermal recording device is as follows.

The one shown in Fig. 2 is a base film 2 coated with a heat-melting ink layer 1, and a transfer sheet (plain paper゛) 3, the base film 2 is heated at the transfer position based on the recorded information, and the heat-melting ink layer 1 is heated.
It is composed of a thermal head 4 which melts the ink of 1 and causes it to adhere to the transfer paper 3I/c, and a drive unit S which controls energization of each of the heating resistors 3I/C based on recording information. Thermal spatula) '4ti, one or more heating resistors are arranged in a row at predetermined intervals on the tip m part.

In the above configuration, the transfer paper 3 superimposed on the base film 2 is continuously or stepwise supplied to the transfer position, and the head driving unit 5 turns on the voltage to the heating resistor of the thermal head 40 according to the recording signal. , when applied in the off state.

Only the heating resistor to which voltage is supplied generates heat.

This heat heats the heat-fusible ink layer 1 directly under the heating resistor through the base film 2, and when the base film 2 and the transfer paper 3 are separated, the heated ink is transferred to the base film 2 and 9. It is peeled off and attached to the transfer paper 3, and transfer recording is performed. Because the configuration is easy like this.

It is suitable for applications that aim to downsize the device.

[Problem that the invention seeks to solve]

However, in a conventional transfer type thermal recording device, when a plurality of heating resistors are used in one head, there is variation in the resistance value of each resistor.

Even if the amount of electricity is the same, the amount of heat generated by the heating resistor varies, and therefore the amount of heat applied to the heat-melting ink also varies, causing a problem of causing density irregularities 2 in the recorded image.

[Means and effects for solving the problems] The present invention has been made in view of the above.

In order to eliminate unevenness in the density of recorded images caused by variations in the resistance values of the resistance heating elements of the thermal head, the recording density of the recording sample is determined, and the resistance value of each heating resistor is calculated backward based on this recording density.

Based on these, the present invention provides a transfer type thermal recording device in which the energization time of each heating resistor is controlled so that the thermal energy generated by each heating resistor becomes constant.

〔Example〕

The transfer type thermal recording apparatus according to the present invention will be explained in detail below.

FIG. 1 shows an embodiment of the present invention, in which a recording sample 10'100D4! was recorded using a thermal head 16 to be controlled in order to know the recording density. 'ii optical system 11 for scanning and photo-to-electrical conversion.

a recording density calculation circuit 12 that calculates recording density based on the output signal obtained by the sensor 1l-11;
A resistance value graph is used to back-calculate the resistance value of each heating resistor in the thermal head 16 based on the recording density signal outputted from the second process.
a printing energy calculation circuit 14 that calculates the energization time such that the thermal energy supplied to the heat-fusible ink by each heating resistor can be constant based on the resistance value calculated by the calculating circuit 13 and the times % 131c; It is composed of a thermal head 16t, a thermal head 16t, and a thermal drive circuit 15 which controls the current conduction time 1 based on the output signal of the print 2-character energy calculation circuit 14 and drives the thermal head 16t based on the recording information.

In the above configuration, first, the thermal head drive unit l61
5 and prints the thermal head 1 based on the recorded information.
A driving voltage is applied to 6, and a test print is made on recording paper.

Then, the optical sensor 115 scans the recording paper lO on which - is printed, reads it, and converts it into an electric signal. Based on the output signal of the sensor 11, a recording density calculation circuit 12 calculates the recording density and intensity of each heating resistor. - Even if each heating resistor is energized for the same time duration, the thermal energy supplied to the heat-melting ink differs by the resistance value of one heating resistor. That is, the resistance value R depends on the resistance value R of v2/几 (V is the applied voltage)5. -Although heat is generated, this corresponds to the energetic recording density. Therefore, the resistance value of the heating resistor is calculated by the resistance value calculating circuit 13 from the recording density information. The large thermal energy generated by each individual angular thermal resistance and antibody is 5. Within the driving time, if the applied voltage is constant, the resistance value R and the energizing time are as follows:
[Determined by Therefore, in order to make the heat generation energy of each ax heating resistor uniform, it is necessary to control the power-off state according to the resistance value. 1 energization time is determined and outputted to the thermal 2nd and 2nd drive circuits 15. The thermal head drive circuit 15 (-1) determines the heating resistor to be energized based on the recorded information, and controls the energization time according to the time determined by the total printing energy calculation circuit 14. When each heating resistor generates heat, the same thermal energy is applied to the heat-melting ink from each resistor, so that the recording density becomes uniform.

FIG. 3 shows the configuration of a specific embodiment of the present invention, and since the same parts as in FIG. The control unit 2 consists of a microcombi and a
This is done by setting it to 0. Further, since the arithmetic unit 20 performs all processing digitally, an A/D converter 17 is provided for digitally converting the analog signal output from the optical sensor 11.

The calculation unit 20 receives the output signal of the A/D converter 17 and the test signal, and calculates each of the input interface 7 and 8 20m, which receives the output signal and the test signal and outputs it as data to the pass line 20b, the recording density, the resistance value, and the energization time. A ROM 20e that stores a program to perform the operations, an OPU 20d that executes processing according to the program in the ROM 20c, and a non-volatile memory module 20 that stores the calculation results and is stored in a battery-powered buffer.・When receiving an address signal from the thermal head drive circuit 15, an output interface 7/8 20f outputs to the thermal head drive circuit 15 a printing energization time value for the resistance value corresponding to the address.
It consists of

In the above configuration, the operation will be explained based on the flowchart in FIG. 4. When measuring the resistance value, the calculation unit 2
Apply a test signal to 0.

The arithmetic unit 2o that receives this test signal is stored in the ROM in advance.
The recording pattern signal for recording density measurement set in 20c is output to the thermal head drive circuit 15 from the output interface 20f. This recording pattern is a signal that causes a voltage of the same pulse width (that is, the same current-carrying time width) to be applied to all of the heating resistors in the thermal head 16, and based on this signal, the thermal head 16 't-drive to record on the transfer paper 10. Record sample made from this record.

The entire main scanning direction is scanned by an optical sensor 11 in which the COD is arranged at the same density as the heating resistor.

A read signal is obtained by receiving reflected light from the light source provided in the optical sensor 11 at the COD, and this signal is converted into a digital signal by the A/D converter 17 and then sent to the arithmetic unit 20. is output to. The arithmetic unit 20 reads data such as the input interface 7, 8, 20 ar, etc.
After storing it in the volatile memory area of AM 20.
Execute the process shown in the figure.

First, the recorded density sound of each heating resistor is read based on the data and calculated in order, and the resistance value is calculated based on the calculation result, and then the resistance value is stored in the nonvolatile memory area of the t-RAM 20e. .

Each of these resistance values corresponds to each of the heating resistors of the thermal head 160 in a ratio of 1 to 1, and a.

Address addresses are assigned in a one-to-one correspondence. Therefore, based on the recording information, when performing normal recording, the length-round head drive circuit 15 sends an address signal corresponding to the heat generating resistor to the calculation unit 20, and calculates the resistance value corresponding to the specified address. One reading time ta is calculated from the RAM 20m, and the result is sent back to the thermal head drive circuit 15 via the output interface 20f. The following processing is performed sequentially for each VC each time an address signal is received or received. The thermal head drive vJ circuit 15 controls the thermal head drive circuit 16 based on the energization time information from the calculation unit 20.
energizes the corresponding heating resistor based on all recorded information.

〔Effect of the invention〕

According to the transfer type thermal recording apparatus of the present invention as described above, the resistance value of each heating resistor is calculated based on the recording density, and the energization time of the corresponding heating resistor is determined from this resistance value, and the thermal By driving , , and , it is possible to eliminate unevenness in the density of a recorded image caused by variations in the resistance value of the heating resistor, thereby improving the quality of one image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of a conventional transfer type thermal recording device, and FIG. 3 is a specific embodiment of the transfer type thermal recording device according to the present invention. The block diagram and FIG. 4 are flowcharts showing an example of processing in the embodiment of the third factor. Explanation of symbols 1O...recording/puku, 11...optical sensor. 12... Recording density calculation circuit, 13... Resistance value calculation circuit, 14... Print energy calculation circuit, 15
...to thermal, de drive circuit, 16...to thermal, de. Figure 1

Claims (1)

[Scope of Claims] Transfer of heat-melting ink applied to a base by selectively heating a heating resistor group of a thermal head based on a recording signal, and transferring the melted ink to transfer paper to record an image. type thermal recording device includes a density detection means for measuring recording density based on a recording sample obtained by driving a heating resistor, and a resistance value of the heating resistor based on the recording density obtained by the means. and a calculation means for calculating the energization time of the heating resistor based on the resistance value, and a driving means for driving the corresponding heating resistor based on the energization time obtained by the calculation means. A transfer type thermal recording device characterized by: