JPS60186169A - Control system for subscanning feed - Google Patents

Abstract

PURPOSE:To prevent irregularity of feed in a recording device which varies in recording time with the number of black picture elements by accelerating or decelerating a stepping motor for subscanning gradually according to the count result of the number of black picture elements. CONSTITUTION:Black picture elements on lines before recording lines are counted to detect previously variation in recording time per one line, and the stepping motor 13 is accelerated or decelerated gradually according to the count result. Therefore, subscanning feed is controlled smoothly without using any high-performance motor as the stepping motor 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording device that records an image line by line using recording elements for one line. The present invention relates to a method for controlling the sub-scanning feed of recording paper in a recording apparatus whose configuration changes depending on the configuration.

Conventional Structure and Problems In a thermal recording apparatus, the recording speed is the highest if the heating elements (recording elements) for one line are driven simultaneously and one line is recorded at once. In that case, the recording current is at its maximum when recording a line in which all pixels are black. However, since the proportion of black pixels in one line (black ratio) is generally less than ten percent, it is extremely uneconomical to provide a large capacity power supply that can supply such a maximum recording current.

Therefore, lines in which the number of black pixels is less than a certain value M are recorded in one go, and lines in which the number of black pixels exceeds a certain value M are recorded in several times so that the number of black pixels recorded at the same time is less than M. A so-called fixed bit recording method has been devised. According to this method, since it is sufficient to supply the recording current necessary to simultaneously record up to M black pixels, the capacity of the recording power source can be reduced and it is economical.

However, in the case of the constant bit recording method, since the recording time of one line changes depending on the number of black pixels included in that line, there is a problem in that feeding shimura occurs in the case of high-speed recording.

This problem can be solved by using a stepping motor with excellent response characteristics as a stepping motor for sub-scanning, but such high-performance stepping motors are extremely expensive and require a lot of effort in recording equipment. This will lead to an increase in costs.

OBJECTS OF THE INVENTION The present invention solves the problems of the prior art, and enables high-speed recording without uneven feeding without using a very high-performance stepping motor for sub-scanning feeding of recording paper. The purpose is to provide a sub-scanning feed control method.

Structure of the Invention The present invention detects changes in the recording time per line in advance by counting the number of black pixels in the line before the recording line, and gradually accelerates or decelerates the stepping moke for sub-scanning. By doing so, we aim to achieve the above objectives.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a thermal recording apparatus according to an embodiment of the present invention. In this figure, 1 is a page memory for storing image signals for one page. 2 is a line enable generation circuit that generates a line enable signal 5YNC. 3 and 4.5 are line memories each for storing one line worth of image signals.

When the line enable signal 5YNC is turned on, the image signal PIXo is output from the page memory 1 in synchronization with the clock CLK. Line memory 3, 4゜6 is clock CLK
Writing and reading are performed in synchronization with. Page memory 1
The image signal PIXo outputted from the line memory 3 is sequentially stored in the line memory 3, and the image signal PIX1 outputted from the line memory 3 at the same time is stored in the line memory 4. At the same time, the image signal PIX2 output from the line memory 4 is sequentially stored in the line memory 5. At the same time, line memory 6
Image signal PIX is output from )? -However, this is the image signal of the memory line.

6.7. ．． 8.9 is the image signal PIXo, PIX1゜PIX
2. This is a counter that divides the black pixels included in PIX. The number of pixels on one line is 2048, and the counter 6
is 1536, which corresponds to the number of pixels for 374 lines.
If the value exceeds 0, an overflow signal is output. The counter 7 outputs an overflow signal when its value exceeds 1024, the number of pixels for 172 lines. Color/R8 outputs an overflow signal when its value exceeds 512, which corresponds to the number of pixels for 174 lines. Counter 9 can count 2Q48m which corresponds to one line.
The value of this counter 9 indicates the number of black pixels included in the recording line.

10 is an OR gate which ORs the overflow signals output from the counters 6, 7, and 8 to create a signal PUP. Reference numeral 11 denotes a stepping pulse generation circuit that generates a stepping pulse MOT. This step and ping pulse MOT are input to the motor driver 12. Reference numeral 13 denotes a stepping motor for sub-scanning and feeding the recording paper, and is driven by the mortar driver 12.

14 is a thermal head equipped with a driver, which includes a heating element for one line, a shift register for serial/parallel conversion of the image signal, a latch for temporarily storing the image signal for one line, and a latch for temporarily storing the image signal for one line. It consists of a drive circuit that drives a heating element according to stored image signals. In this embodiment (C), the heating elements are divided into 4 units of 612 (for 1/4 line), and recording pulses ENB (1) to E N B <4) corresponding to blocks are applied. 15 is a recording block control circuit which drives the heating element in each block of the thermal head 14 according to the value of the counter 9 (the number of black pixels of the recording line). Control the drive. In other words, the number of times a recording line is recorded is controlled according to the number of black pixels. This recording block control circuit 16 outputs recording pulses E N j3 (1j to E N
E (4) and strobe pulse STB are sent out.

In this example, the recording time per line is 2 m5ec when one line is driven simultaneously (simultaneously driving 4 blocks), and 4 m5ec when one line is driven in two steps.
m5eC1, What happens when one line is driven in 3 times?
m5ec, and 8m5ec when one line is divided into four and driven (when driven one block at a time).

Next, all pixels (2048 pixels) are before and after the black line,
There are consecutive lines in which the number of black pixels is 512 or less, and the image signals of the lines in which the number of black pixels is 612 or less are stored in line memos IJ 3, 4, and 5, and then page memory 1 is stored.
The operation when an image signal of an all-pixel black line is output from is explained. FIG. 2 is a timing chart in such a case.

Now, the operation during the period when the image signals stored in the line memories 3, 4, and 5 are output from the page memory 1 will be explained. During this period, the line enable signal SYN is generated from the line enable generation circuit 2 at a cycle of 2m5ec.
is sent out, and the image signal is outputted to the page memory 1 line by line at that period. At the same time, the line memory 5 outputs both the recording R/I signals PIX. This image signal PI
X is sequentially input to the shift register of the thermal head 14 in synchronization with the clock CLK. When the input of both signals PIX is completed, the recording block control circuit produces a calatrope pulse STB, and inside the thermal head 14, the image signal of the recording line stored in the shift register is transferred to the launch. Subsequently, the recording block control circuits 15 to 4
Recording pulses for blocks ENB(r) to ENB (
4) are sent out at the same time, the thermal head 14
The heating elements of the blocks are driven all at once to record a recording line at once. The stepping pulse generation circuit 11 outputs a stepping pulse MOT in synchronization with the rise of the line enable signal 5YNC, and the recording paper is fed at a constant speed (2m5eC/line).

Now, when both signals P I
are sequentially written to the line memory 3, and at the same time, the image signals stored in the line memories 3 and 4 are written to the line memory 4 in the subsequent stage.
, 5 and stored in the line memory 5 are transferred to the thermal head 1jltC and recorded.

During the output of this image signal P I Xo in which all pixels are black, the count value of the counter 6 exceeds 1636,
Since an overflow signal is output from , the signal PUP is generated. When this signal PUP is generated, the line enable generation circuit 2 switches the cycle of the line enable signal 5YNC from 2m5ec to 4m8ec from the next line, and also changes the cycle of the stepping pulse generation circuit 11+j and the stenobin fA/L/SMOT. 1 line - double the number of simultaneous drives.

When the output of the image signal PIXo for the all-pixel black line is finished, the line/enable signal 5YNC is sent out again from the line/enable generation circuit 2, and the image signal PIXo for the next line is output.
XO (the number of black pixels is 512 or less) is output from the page memory 1. At this time, line enable signal 5YNC
The cycle of is 4 m5 ec, and the cycle of the stepping pulse MOT output from the stepping pulse generation circuit 11 is twice that of the one-line simultaneous drive recording. The stepping motor 13 is decelerated.

Note that since the number of black pixels of the image signal PIX of the recording line outputted from the line memory 5 is 1512 or more, the recording block control circuit 15 outputs recording pulses ENB(1) to EN for all blocks. B (4) is sent out all at once. Therefore, this recording line image signal is recorded once.

Furthermore, since the image signal PIx1 outputted from the line memory 3 has all pixels black, the signal PUP is generated unless an overflow signal is outputted from the counter 7. Due to the generation of this signal PUP, the line enable generation circuit 2
From the next line, the cycle of the line enable signal 5YNC is switched from 4m5ec to 6m5ec, and similarly, the stepping pulse generator 11 generates a stepping pulse M
When the recording of one line is completed in this way by changing the OT cycle to three times that of one line simultaneous recording, the line enable generation circuit 2 outputs the line enable generation circuit 4J and the line enable signals S and YNC. The image signal PIXo of the next line (the number of black pixels is 512 or less) is output. At this time, the period of line enable signal 5YNC is 6m5e
It is C. Also, the period of the stepping pulse MOT is
This is three times the speed when recording one line all at once, and the stepping motor 13 is further decelerated.

In fact, during the output of the image signal PIX○, an overflow signal is output from the counter 7, and a PUP signal is generated. As a result, the line enable generation circuit 2 changes the period of the line enable signal 5YNC from the next line to 8m5ec.
Switch to Good luck, stepping pulse generation circuit 11
switches the cycle of the stepping pulse MOT to four times that of one line simultaneous recording.

When the output of the image signal PIXo is completed, the image signals of the recording line (the number of black pixels is 612 or less) transferred from the line memory 5 to the thermal head 14 are recorded simultaneously on one line.

When recording of one line is finished in this way, the line enable signal 5YNC is outputted from the line enable generation circuit 2 again, and the image signal PIX○ of the next line (the number of black pixels is 612 or less) is outputted from the page memory 1. be done.

Since the number of black pixels included in the image signal PIX (value of the counter 9) exceeds 1536, the recording block control circuit 15 outputs recording pulses ENB(1) to ENB(1) to E corresponding to each block.
NB(4) are generated one by one in sequence. Therefore, the all-pixel black line is recorded four times, one block at a time. At this time, the cycle of the stepping pulse MOT is 1
Since this is four times the speed in the case of simultaneous line recording, the sub-scanning feed speed of the recording paper is 8 m5ec/line.

In this way, from the time when the image signal of the all-pixel black line, which takes a long recording time, is output from the page memory 1, the cycle of the stepping pulse MOT is gradually increased, and the stepping motor 13 is gradually decelerated.

◇ During the period in which the all-pixel black line image signal is output from the line memory 5, no overflow signal is output from any of the counters 6, 7, and 8, and therefore, the signal PUP is not generated. If signal PUP is not generated, line enable generation circuit 2 generates line enable signal 5 from the next line.
Switch the YNC cycle from 8m5ec to 6m5ec,
Similarly, the stepping pulse generation circuit 11 adjusts the cycle of the stepping pulse MOT from 1 line to 3 in the case of simultaneous recording.
Switch to double.

Thereafter, the image signals of lines with 512 or fewer black pixels are sequentially output from the page memory 1, but since the signal PUP is not generated, the line enable generation circuit 2 changes the period of the line enable signal 5YNC to 4 m for each line. Sec.
2m Sec and 2m5e
After reaching the line enable signal 5YNC, the end of the line enable signal 5YNC is fixed at 2m5ec when the signal PUP is input. Also, the period of line enable signal 5YNC is 5m5.
Even if the signal PUP is inputted again after reaching ec, the period will be only 5m5ec.

Similarly, the stepping pulse generation circuit 11 adjusts the cycle of the stepping pulse MOT from 1 line to 3 in the case of simultaneous recording.
The cycle is sequentially switched to double, double the period in the case of 1 line-simultaneous recording, and twice the period in the case of 1 line-simultaneous recording. When the cycle for one line simultaneous recording is reached, the cycle is maintained at that cycle unless the signal PUP is input again. Furthermore, after the cycle of the stepping pulse MOT reaches four times that in the case of one-line simultaneous recording, the cycle is maintained at that cycle even if the signal PUP is input again.

Therefore, after recording that all pixels are 3-in, the steering motor 13 is gradually accelerated and 3-in, as shown in FIG.
From the line onwards, sub-scanning feed is performed at a speed of 2 m5ec/line.

In this way, the number of black pixels in the line before the recording line is counted, and according to the counting result, the stepping motor 13
Since the stepping motor 13 is gradually decelerated or accelerated, the sub-scanning feed can be smoothly controlled without using a very high-performance stepping motor 13, and recording unevenness can be prevented from occurring.

Above, we have explained the operation when there are consecutive lines with 512 or less black pixels before and after a line where all pixels are black.
In other cases as well, it is possible to prevent the feed from occurring in the same way.

In the above embodiment, the reason why the counter 6 with the largest counter value that generates an overflow signal is placed at the most ifJ is to detect the line where the recording time is the longest as early as possible, and to decelerate the stepping motor 13. This is to get started.

Although one embodiment has been described above, the present invention is not limited to the configuration of the above embodiment, but can be implemented with appropriate modifications. Further, the present invention can be applied to recording devices other than thermal recording devices.

Effects of the Invention According to the present invention, the number of black pixels in the line before the recording line is counted, and the stepping motor for sub-scanning feed of the recording paper is gradually accelerated or decelerated according to the counting result. As a ping motor, it is possible to perform high-speed recording without uneven feeding without using a very high-performance and expensive ping motor.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a thermal recording device according to an embodiment of the present invention, and FIG. 2 is a timing diagram of the same device. 1 Page memory, 2... Line enable generation circuit, 3, 4.5 Line memory, 617°-stepping generation circuit, 12- Morph driver, 13 Stepping motor, 14... To thermal, Do, 1
5... Recording block 11il engraving 1) Circuit.

Claims (1)

[Claims] A recording paper sub-scanning feed control method in a recording device in which the recording time of one line changes depending on the number of black pixels included in that line, and the number of black pixels in one or more lines before the recording line is counted. The sub-scanning feed control method is characterized in that the sub-scanning feed step/knob motor is gradually accelerated or decelerated according to the counting result.