JPH0958044A - Recording apparatus and recording control method - Google Patents

Abstract

The present invention provides a recording apparatus and a recording control method that can always obtain an appropriate recording density even under the condition that the recording speed changes without requiring a large capacity power source. SOLUTION: The energization time to each block (blocks 1 to 8) by the block drive signals 49-1 to 49-8 is set according to the elapsed time from the time when the block was previously energized to the time when the current is energized. to correct. For example, in the order in which power is sequentially applied from block 1 to block 8, the elapsed time from the previous power-on time to the current power-on time becomes longer in order from block 1 to block 8. Therefore, according to the length, , Block the current energizing time 1
It is controlled so as to sequentially increase from the block to the block 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus and a recording control method, and more particularly to a recording apparatus and a recording control method using a recording head for recording by a thermal transfer method.

[0002]

2. Description of the Related Art In a thermal head having a plurality of heating elements, which are current-carrying elements arranged in rows, the heating elements are divided into a plurality of blocks, and the plurality of blocks are sequentially read one by one or a plurality of blocks. Recording is performed by heating the heating element by energizing the heating element in a divided manner, and transferring the heat to a recording medium such as a thermal paper or an ink ribbon that is in contact with the heating element. Therefore, in order to obtain an appropriate recording density on the recording medium, it is important to control the temperature of the heating element.

Conventionally, as a density correction method in recording using the thermal head having the above-mentioned structure, a temperature detecting sensor is provided on the thermal head and the energy applied to the heating element of the thermal head is controlled according to the sensor output. There is. That is, when the temperature of the thermal head is high, the applied energy is decreased, and when the temperature is low, the applied energy is increased to keep the heating temperature of the heating element constant, and as a result, it is possible to always obtain an appropriate density recording. Control it.

By the way, the temperature of the heating element itself is known in addition to the temperature of the entire thermal head as a factor that determines the proper density in recording using the thermal head. The temperature of the heating element changes depending on the recording speed. That is,
When the recording speed is fast, the time for cooling the heating element is short, so the temperature is high, and conversely, when the storage speed is slow, the temperature is low. For this reason, in the recording using the thermal head, the energy required to obtain an appropriate recording density differs depending on the recording speed. However, in the conventional recording apparatus, since the recording control is performed so that the recording speed is always constant, it is possible to obtain an appropriate recording density by controlling the applied energy by focusing only on the temperature of the entire thermal head. It was possible.

[0005]

When high-speed recording is required, the amount of data in the scanning line when scanning and recording with the thermal head is increased in order to increase the recording speed as much as possible. When the number of blocks is large, recording is performed by sequentially energizing each block for recording, and when the amount of data is small, it is necessary to perform recording control by energizing a plurality of blocks and recording. That is, since there is a limit to the number of heating elements that can be energized at the same time depending on the capacity of the device power supply, the blocks are energized collectively within the range.

However, in such a recording control, the recording speed is constantly changed for each scanning line of the head, and if the applied energy is controlled only according to the temperature of the entire thermal head, the recording is performed at a high recording speed. There is a problem in that the density becomes high, and conversely, when the recording speed is slow, the recording density becomes light and uneven density occurs.

In order to solve this problem, there is an energization control in which a constant heating element is always energized in a plurality of blocks regardless of the amount of data in the scanning line in order to keep the recording speed constant. However, such control requires a large-capacity power supply, which has a drawback of increasing the size of the device. The present invention has been made in view of the above conventional example,
It is an object of the present invention to provide a recording apparatus and a recording control method that can always obtain an appropriate recording density even under the condition that the recording speed changes without requiring a large capacity power source.

[0008]

The recording apparatus of the present invention for achieving the above object has the following constitution. That is, a recording apparatus for recording an image on a recording medium by driving a recording head having a plurality of recording elements, wherein the plurality of recording elements are divided into a plurality of blocks, and each block is timed according to image data. Recording means for energizing the divided areas for recording, detecting means for detecting the elapsed time from the end of energizing one block until energizing the same block again, and the elapsed time detected by the detecting means And a control unit that controls to change the electric energy applied to each block according to the above.

According to another aspect of the invention, a recording control method for dividing a plurality of recording elements into a plurality of blocks and sequentially energizing each of the plurality of blocks in a time division manner to record an image on a recording medium. The detection step of detecting the elapsed time from the end of energization of one block to the energization of the same block again, and applying to each block according to the elapsed time detected in the detection step And a control step of controlling so as to change the electric energy for performing the recording control method.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention having the above configuration, when a plurality of recording elements are divided into a plurality of blocks and each of the plurality of blocks is sequentially energized in a time division manner to record an image on a recording medium In addition, the elapsed time from the end of energization of one block to the energization of the same block again is detected, and control is performed so that the electric energy applied to each block is changed according to the detected elapsed time. To work.

At this time, the temperature of the recording head having a plurality of recording elements is detected, and the detected temperature is taken into consideration.
You may control so that the electric energy applied to each block may be changed. The applied electric energy is changed by changing the energization time for energizing each block, or by changing the energizing voltage applied to each block.

Further, each of the plurality of recording elements has a converter for converting the applied electric energy into heat energy, and recording is performed on the recording medium by the action of the heat energy obtained by the converter. . Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. <Schematic Description of Apparatus Main Body> FIG. 1 shows a thermal transfer printer HT equipped with a thermal head, which is a typical embodiment of the present invention.
It is an appearance perspective view showing the outline of the composition of P. In FIG. 1, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5009 to 5011 in association with the forward and reverse rotation of the drive motor 5013 has a pin (not shown). Guide rail 50
It is supported by 03 and reciprocates in the directions of arrows a and b. A thermal recording head (hereinafter referred to as a thermal head) TH is mounted on the carriage HC. A paper pressing plate 5002 presses the recording paper P against the platen 5000 in the moving direction of the carriage HC. 5007,
5008 is a photocoupler, which is a lever 500 of the carriage.
6 is a home position detector for confirming the existence of 6 in this region and switching the rotation direction of the motor 5013. Reference numeral 5018 is a main body support plate.

<Description of Control Configuration> Next, a control configuration for executing the recording control of the above-mentioned apparatus will be described.
FIG. 2 is a block diagram showing the configuration of the control circuit 100 of the thermal transfer printer HTP and its peripheral portion. In FIG. 2, 1
700 is an interface for inputting image data from an external device such as a host computer, 1701 is an MPU, 1
Reference numeral 702 is a ROM that stores a control program executed by the MPU 1701, and reference numeral 1703 is a DRAM that stores various types of data (the image data, the image signal supplied to the thermal head TH, and the like). A gate array (G. 1704) controls the supply of image signals to the recording head TH.
A. ), The interface 1700, the MPU 170
1. Data transfer control between the RAMs 1703 is also performed. 171
0 is a carrier motor for carrying the recording head TH,
Reference numeral 1709 denotes a carry motor for carrying the recording paper. 17
Reference numeral 05 is a head driver for driving the thermal head, 17
Reference numerals 06 to 1707 denote motor drivers for driving the carry motor 1709 and the carrier motor 1710, respectively.

The operation of the above control structure will be described. When a recording signal is input to the interface 1700, the gate array 17
04 and the MPU 1701 converts the recording signal into recording data for printing. Then, the motor driver 17
06 and 1707 are driven, and the head driver 1
Thermal head TH according to the image signal sent to 705
Is driven, and recording is performed.

The thermal head TH is equipped with a thermistor 1708 for measuring the temperature of the thermal head TH, and its output is sent to the control circuit 100. FIG. 3 shows the configuration of the logic circuit of the thermal head TH and the thermal head TH.
FIG. 3 is a block diagram showing a detailed configuration of a head driver 1705 that drives the. In FIG. 3, reference numeral 1 is a control circuit 100.
2 is a line buffer for storing an image signal for one scanning line of the thermal head TH output from the control circuit 100, and 3 is an image signal read from the line buffer 2. Reference numeral 4 is a 1-line data input completion signal for informing the sequence controller 8 that the image signal for one line is supplied to the line buffer 2, and 5 is the thermistor 170.
A temperature signal obtained by processing the temperature information of the thermal head TH detected by the control circuit 100 is input to the control circuit 100, and 6 is used to determine the time for energizing the heating resistor of the thermal head TH based on the temperature signal 5. A table (heat table) 7 is an energization time signal determined by the heat table 6.

Further, 8 is a sequence controller provided with a memory 8a for performing various controls described later, 9 is a block switching signal, and 10 is a block switching signal 9 output from the sequence controller 8 to energize the thermal head TH. A block switching circuit for switching the heating resistor block, 12 is a clock signal for serially transferring the image signal 3 to the thermal head TH, and 13
Is a reset signal, 14 is a latch signal, 49-1 to 49-
Reference numeral 8 is a block drive signal for energizing and driving each block of the thermal head TH, 16 is a read start instruction signal for starting data read of the line buffer 2, 1
Reference numeral 7 is an address counter that starts counting by the start instruction signal 16, and reference numeral 18 is a control signal for transmitting a response or request from the sequence controller 8 to the control circuit 100.
The line buffer 2 is accessed by the address data output from the counter 17.

Further, 50 is a black dot counter for calculating the number of black dots included in the image signal transferred from the line buffer 2 to the thermal head TH, and 51 is a block based on the number of black dots calculated by the black dot counter 50. The combination signal 51. The block combination signal 51 is output to the sequence controller 8, and the sequence controller 8 determines the combination of blocks.

Reference numeral 20 is a correction time 21b for correcting the energization time signal 7 in order to determine the actual energization time based on the elapsed time signal 21a output from the sequence controller 8.
An elapsed time correction table for determining is, 40 is a power source for supplying power to the thermal head TH. Next, the components of the thermal head TH will be described.

Reference numeral 44 is a shift register for serially inputting the image signal 3 in synchronization with the clock 12 output from the sequence controller 8, 45 is a latch circuit for latching the image signal stored in the shift register 44, 46-1
Numerals 46-8 are switching circuits for switching whether or not to energize the corresponding heating resistor according to the image signal latched by the latch circuit 45, and 47 is a heating resistor. As is clear from such a configuration, the heating resistor is divided into eight blocks by the switching circuits 46-1 to 46-8 and the block drive signals 49-1 to 49-8, and the energization drive is performed for each of these blocks. To be done.

Hereinafter, the switching circuits 46-1 to 46-
A heating resistor group connected to each of the eight is referred to as block 1, block 2, ..., Block 8. Here, FIG. 2 and FIG.
Comparing with, the head driver 1705 has a line buffer 2, a heat table 6, a sequence controller 8, a block switching circuit 10, an address counter 17, an elapsed time correction table 20, and a black dot counter 5.
It can be seen that it is composed of zero.

FIG. 4 is a time chart showing the timing of various signals shown in FIG. In FIG. 4, (a) is 1
The line data input completion signal 4, (b) is the reset signal 13 of the shift register 44, (c) is the clock signal 12,
(D) is the image signal 13, (e) is the latch signal 14,
Each of (f) to (i) is a block drive signal 49-.
1, 49-2, 49-3 to 49-8 are shown.

First, when the image signal 1 to be recorded in the line buffer 2 is supplied for one line, the 1-line data input completion signal 4 (FIG. 4A) is supplied to the sequence controller 8 at the completion of the supply. It Based on this, the sequence controller 8 shifts the shift reset signal 13 (see FIG.
(B)) is generated. When the shift reset signal 13 is input, the shift register 44 resets all the data that has been stored so far and clears the inside of the register. At this point, the sequence controller 8 sends out the read start signal 16 to the address counter 17, and sequentially starts reading from the beginning of the image signal stored in the line buffer 2 (FIG. 4 (d)).

The image signal 3 read out and output from the line buffer 2 is supplied to the shift register 44 and the black dot counter 50, and the number of black dots is counted for each block. Then, the block combination signal 51 is supplied to the sequence controller 8 based on the counted numerical values. On the other hand, in the heat table 6, the basic heating time is determined based on the temperature signal 5,
The sequence controller 8 uses this as an energization time signal 7.
To supply.

The sequence controller 8 calculates the elapsed time from the end of energization for each block until the same block is energized again from the block combination signal 51 and the energization time signal 7, and this is calculated as the elapsed time signal. 21
It is supplied to the elapsed time correction table 20 as a, and the correction time 21b for determining the actual energization time is obtained. And
The elapsed time and the actual energization time corrected by the correction time 21b are stored in the memory 8a provided in the sequence controller 8.

FIG. 5 is a time chart showing an example of the energization timing of each block and the elapsed time until the next energization after the end of energization. In this example, the first line includes block drive signals 49-1 for blocks 1 to 8 all at once.
~ 49-8 shows the respective block drive signals in the case where the second line is sequentially energized 8 times in sequence such as block 1, block 2, ... There is. This block energization order is
It is determined by the sequence controller 8 based on the block combination signal 51 based on the number of black dots of the input image signal for one line and the distribution of the number of black dots.

In the example shown in FIG. 5, the energization time of each block in the recording of the first line is equal to each other (all are A1), but the energization time of each block in the recording of the second line is A2 <B2 <. C2 <D2 <E2 <F2 <G2
<H2, Block 1 → Block 2 → …… →
Block 8 is getting longer in sequence. This is for the following reason.

That is, when the elapsed time from the end of energization of one block to the energization of the same block is different for each block as shown in FIG. 5, the cooling period of the heating resistor of each block is , The temperature of the heating resistor of the block in the second line is the highest in the block 1,
If the same energy is applied to all the blocks in this state (the same energization time is given), the recording density becomes the highest in the block 1 and the lightest in the block 8, resulting in the lowest density in the block 8. , Uneven density appears in the recorded image. Therefore, in this embodiment, the recording densities of the blocks 1 to 8 are made equal by correcting the next energization time of each block according to the elapsed time (that is, by increasing the energization time as the elapsed time increases). It is controlled to become.

The elapsed time is calculated by, for example, the elapsed time with respect to the pulse width C2 of the block drive signal 49-3 of the block 3 of the second line shown in FIG.
Similarly, the block drive signal 4 of the block 4 of the second line
The elapsed time for the pulse width D2 of 9-4 is A2 + B2 +
It is calculated by C2. This will be described step by step. First, at the moment when the block combination signal 51 and the energization time signal 7 are input to the sequence controller 8, the elapsed time of all blocks is initialized to "0". Next, referring to the elapsed time correction table 20, this elapsed time is corrected by the correction time 2
1b is obtained, and the energization time A2 of the block 1 is determined from the correction time and the energization time signal 7. At the same time, the elapsed time of block 1 is reset to “0”, and blocks 2 to 8
The elapsed time of is A2. Similarly, this elapsed time A
2 is obtained by referring to the elapsed time correction table 20 and a new correction time 21b is obtained. From the correction time and the energization time signal 7, the energization time B2 of the block 2 is determined, and the elapsed time of the block 2 is reset to "0". It And blocks 3-8
B2 is added to the elapsed time of, and the elapsed time is A2 +
B2. By repeating the above procedure, the elapsed time and energization time of each block are determined.

Further, the image signal 3 is synchronized with the clock signal 12 (FIG. 4 (c)) output from the sequence controller 8 at the start of its transmission, and the shift register 44
Is forwarded to The clock signal 12 is stopped at the stage where the beginning of the read image signal 3 has been shifted to the final stage of the shift register 44 (at the time when the number of heating resistors is reached).

By this time, the sequence controller 8
A clock counter (not shown) in the clock signal 12
The number of pulses is counted, and the latch signal 14 (FIG. 4E) is output when the generation of the clock signal 12 is stopped. When the latch signal 14 is output, the latch circuit 45 latches the data output from the shift register 44 in parallel. After that, the sequence controller 8 supplies the block switching signal 9 to the block switching circuit 10 based on the stored energization time. This allows
The block switching circuit 10 uses the block switching signal 9
Based on the above, the block drive signals 49-1 to 49-8 (FIGS. 4F to 4I) are switched and output. Each of the block drive signals 49-1 to 49-8 is supplied to the switching circuit 4
Each of the blocks 6-1 to 46-8 is operated to supply power to the heating resistor 47 in accordance with a different drive time (corrected energization time) for each block.

While recording this line,
The next one-line data is transferred from the line buffer 2 to the shift register 44, and the sequence controller 8 corrects the energization time for each block and calculates and stores the elapsed time. When the recording of the current line is completed, a latch signal is output and the energization of the next line is started. In this way, the recording operation is repeated.

Therefore, according to the embodiment described above, in energizing one block, depending on the length of the elapsed time from the end of the last energization of the block until the current energization, Since the control is performed so that the energization time to the block is changed, it is possible to perform recording without density unevenness. In the above example, the time for energizing the heating resistor is changed, but the present invention is not limited to this. For example, the energizing voltage may be controlled to be changed. Further, a thermal head may be configured in which past energization history is retained and the energization time can be controlled for each heating resistor according to the history.

Further, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can be applied to the case where it is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium into the system or device, the system or device operates in a predetermined manner.

[0034]

As described above, according to the present invention, when a plurality of recording elements are divided into a plurality of blocks and each of the plurality of blocks is sequentially energized in a time division manner to record an image on a recording medium. In addition, the elapsed time from the end of energization of one block to the energization of the same block again is detected, and control is performed so that the electric energy applied to each block is changed according to the detected elapsed time. Because
For example, even when the recording speed is constantly changing, there is an effect that a proper recording density without density unevenness can always be obtained.

Since each block is energized in a time-division manner, there is an advantage that a large amount of electric power is not required at one time and the device does not need to have a large capacity power source.

[Brief description of drawings]

FIG. 1 is an external perspective view showing the outline of the configuration of a thermal transfer printer HTP including a thermal head that is a typical embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control circuit 100 of a thermal transfer printer HTP and its peripheral portion.

FIG. 3 is a block diagram showing a configuration of a logic circuit of the thermal head TH and a detailed configuration of a head driver 1705 that drives the thermal head TH.

FIG. 4 is a time chart showing timings of various signals shown in FIG.

FIG. 5 is a time chart showing an example of the energization timing of each block and the elapsed time until the next energization after the end of energization.

[Explanation of symbols]

 1, 3 image signals 2 line buffer 4 1 line data input completion signal 5 temperature signal 6 heat table 7 energization time signal 8 sequence controller 9 block switching signal 10 block switching circuit 12 clock signal 13 reset signal 14 latch signal 16 read start instruction signal 20 Elapsed time interpolation table 21a Elapsed time signal 21b Correction time 40 Power supply 44 Shift register 45 Latch circuit 46-1 to 46-8 Switching circuit 47 Heating resistor 49-1 to 49-8 Block drive signal 50 Black dot counter 51 Combination signal 100 control circuit 1705 head driver 1708 thermistor TH thermal head

Claims (7)

[Claims] 1. A recording apparatus for recording an image on a recording medium by driving a recording head having a plurality of recording elements, wherein the plurality of recording elements are divided into a plurality of blocks, and image data is created for each block. Accordingly, recording means for energizing in time division for recording, detecting means for detecting an elapsed time from the end of energizing one block to energizing again for the same block, and the detecting means for detecting And a control unit that controls to change the electric energy applied to each block according to the elapsed time. 2. A temperature detection unit for detecting the temperature of the recording head is further provided, and the control unit variably controls the electric energy applied to each block in consideration of the temperature detected by the temperature detection unit. The recording apparatus according to claim 1, wherein: 3. The recording apparatus according to claim 1, wherein the control unit changes an energization time for energizing each of the blocks. 4. The recording apparatus according to claim 1, wherein the control unit changes an energization voltage applied to each of the blocks. 5. The recording apparatus according to claim 1, wherein each of the plurality of recording elements has a converter that converts applied electric energy into heat energy. 6. The recording apparatus according to claim 5, wherein the recording means records on the recording medium by the action of thermal energy obtained by the converter. 7. A recording control method for dividing a plurality of recording elements into a plurality of blocks and sequentially energizing each of the plurality of blocks in a time-division manner to record an image on a recording medium. A detection step of detecting an elapsed time from the end of energization to the block until the same block is energized again, and the electric energy applied to each block is changed according to the elapsed time detected in the detection step. A recording control method, comprising: