JPH02167758A - Image information recording - Google Patents

Abstract

PURPOSE:To obtain a satisfactory recording image by applying a recording pulse only once to record image data after suspension of a step pulse, during the suspension of a recording action and in the meantime, again recording the image data recorded when the recording action is suspended in response to an initially applied recording pulse during the resumption of recording action. CONSTITUTION:If recording action is again resumed after suspending the recording action temporarily, a thermal head produces a vague recording image or recording dots of reduced diameter. Subsequently, during suspension of the recording action, a recording pulse needs to be applied to a thermal head drive circuit only once to record image data after suspension of a step pulse to a stepping motor drive circuit 4. Furthermore, during resumption of the recording action, the image data recorded during suspension of the recording action needs to be recorded again in response to a recording pulse applied initially. In this case, the image data to be recorded twice by the inertia of a stepping motor or a recording paper transport mechanism can be recorded at an almost the same linear position.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to image information recording in which image information is recorded in the main scanning direction by a thermal head while moving a recording paper in the sub-scanning direction by a stepping motor. Regarding the method.

[Prior Art] A thermal recording device that records an image line by line on thermal recording paper using a thermal head is often used in facsimile machines and the like.

For example, in the case of a G3 facsimile machine recommended by the CCITT, each line image information read from a document image is encoded and transmitted. When this encoding is performed, even if the image has the same number of lines, the amount of encoded image information increases or decreases depending on the image pattern.

On the other hand, since the modem that transmits image information is set to a constant data transmission speed, when the amount of image information increases or decreases as described above, the transmission time for one line changes.

Therefore, when the receiving side records an image one line at a time without receiving image information, the receiving side may not be able to catch up with the reception of the image information and may temporarily stop the recording operation.

[Problem to be solved by the invention] By the way, when recording an image with a thermal head, the fifth
As shown in Figure (a), at a recording period of l lines, a pulsed drive current I
Apply d. This energization causes each heating resistor to generate heat, causing the thermal recording paper to develop color.

The image will now be recorded.

However, the temperature of the heating resistor in this case does not increase much during the first pulse of the drive current Id, but begins to increase from the second pulse onwards, as shown in FIG. 2(b).

For this reason, when the thermal head restarts the recording operation after temporarily stopping the recording operation as described above, the temperature of the first line does not rise sufficiently, so the recorded image becomes thin or the recording The dot diameter may become smaller.

FIG. 6 shows an example of an image recording operation, and the step pulse SP is a signal that drives a step motor that conveys the recording paper. Each pulse of this step pulse SP moves the recording paper at one line intervals. The dots P in each line image are recorded by outputting the driving current Id one pulse at a time at the timing of the movement.

In addition, in the example shown in the figure, in order to stop conveyance of the recording paper,
After outputting the step pulse SP and the l pulse corresponding to line i, the output is stopped for a temporary period. in this case,
In actual practice, due to the inertia of the step motor and other drive mechanisms, the recording paper does not ideally stop as shown by the broken line, but moves beyond the broken line position and then returns to that position.

Further, when outputting the step pulse SP is restarted at line i+1, the recording paper does not rise immediately as shown by the broken line, but starts moving after a slight delay.

Therefore, the dot Pi of the line i11 where recording has been resumed is recorded slightly closer to the dot Pi. Also.

Since this line 1+1 is the first line when recording is restarted as described above, the recorded dots become thinner and smaller, and the image density becomes lighter or white spots appear.

In this way, conventionally, when the image recording operation is temporarily stopped, the line image at the recording restart position cannot be recorded at the appropriate density.
There was a problem that good images could not be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image information recording method that solves the above problems and allows good recorded images to be obtained.

[Means for Solving the Problems] To this end, the present invention, when the recording operation is interrupted, applies the recording pulse to the thermal head drive circuit only once after the application of the step pulse to the step motor drive circuit is stopped, and then the image is While information is being recorded, when the recording operation is restarted, the image information that was recorded when the recording operation was interrupted is again recorded in response to the first applied recording pulse.

[Function] When the recording operation is interrupted, the first image information when the recording operation is resumed is recorded, so the image can be recorded at an appropriate density. In this case, when the application of the step pulse is stopped due to the inertia of the step motor or recording paper transport mechanism,
The recording paper moves a certain distance without stopping immediately, and
When the application of the step pulse is restarted when the recording operation is restarted, the movement of the recording paper is delayed, so that the image information to be recorded twice can be recorded at almost the same line position. This makes it possible to obtain a good recorded image.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a block diagram of an image recording apparatus according to an embodiment of the present invention. In the figure, a thermal head 1 records an image on thermal recording paper (not shown). The internal heating resistor array 1a is a heating resistor corresponding to the number of pixels for one line, and the power supply voltage Vc
is applied.

The driver 1b applies a drive current to each heating resistor. The latch circuit 1c holds image information for one line, and the shift register 1d temporarily stores image information for one line. The thermistor le' is
This is to measure the temperature of the thermal head l.

FIFO line buffer 2 is FIFO line buffer 2.
stIn First Out) function, and temporarily stores image information of a certain number of lines. The internal memory 2a is configured to store one line of image information at the l address, and the write pointer 2b is
It shows the write address of the image information to the memory 2a, and the successive pointer 2c shows the read address. The control section 2d controls each section within the FIFO line buffer 2.

The stepping motor 3 is for conveying thermal recording paper (not shown), and the motor active circuit 4 is for driving and controlling the stepping motor 3.

The clock circuit 5 outputs clock signals for various operation timings, and the recording control section 6 controls the thermal head 1, the FIF○ line buffer 2, and the motor excitation circuit 4 based on the timing signals. It is something.

It is assumed that the image recording apparatus of this embodiment has the above configuration and is installed in, for example, a facsimile machine. and,
Assuming that reception of one image is now started, in the case of a facsimile machine, as described above, image information for each line is input at irregular time intervals rather than at regular time intervals.

When this image recording device starts operating, the recording control section 6
Under the control of FIG. 2, storage of irregularly input image information into the FIFO line buffer 2 is started (process 101).

Then, the number of lines of image information stored in the FIF○ line buffer 2 is monitored (processed 102), and the number of lines is
If the number is less than a preset certain number (N in process 102),
Furthermore, it is determined whether or not image information continues to be received (process 103). Then, if reception continues (process 10
4N), return to the above process 102.

By the way, when this operation starts, the clock circuit 5 outputs clock signals PA, PB, and Pc indicating various operation timings, as shown in FIGS. 3(a) to 3(C), and the recording control unit 6 is input.

Then, when the image information in the FIFO line buffer 2 exceeds a certain number of lines (Y in process 102), the clock signal P
A is monitored (process 104), it is at the ``11'' level (Y in process 104), and it is determined whether the line of image information in the FIFO line buffer 2 is not the last line (
Process 105). Currently, a certain number of lines of image information are stored, and this is not the last line.

In this case (Y in process 105), normal recording control is executed. That is, as shown in FIG. 3(d), at the timing of the clock signal PA, the data signal SD of the l-th line image information is read out from the FIF○ line buffer 2 and transferred to the shift register 1d. In parallel with this, the same figure (
As shown in e), at the timing of the clock signal Pa,
A step pulse SP is output to the motor drive circuit 4.

Next, as shown in (f) and (g) of the figure, the latch signal SL is sent to the latch circuit 1c at the timing of the clock signal Pc.
is output and the data signal SD stored in the shift register 1d is held in the latch circuit [C].
The increment signal SI is outputted to indicate the read address of the next l line. And the same figure (h
), the strobe signal SB is output to the driver 1b at the timing of the next clock signal PA. As a result, a predetermined drive current is applied to the heat generating resistor array 1a to generate heat, and one line of image is recorded on a thermal recording paper (not shown). In this case, when the temperature detected by the thermistor 1e is low, the strobe signal S
The amount of heat generated is adjusted by widening the H pulse width and narrowing the pulse width when the temperature is high.

The above control pattern indicated by N in the figure is normal recording control for one line of image information (processing 106).
.

Through the above operations, this normal recording control is activated at each timing of the clock signal P^, and images are sequentially recorded one line at a time. In this case, at the timing of the clock signal PA, the data signal SD of the next line is transferred to the shift register 1d in parallel with the image recording of the l line, and the shift register 1d operates in parallel.

Here, if the recording speed is faster than the receiving speed of image information, the image information in the FIF○ line buffer 2 will decrease.

In this manner, when the image information in the FIFO line buffer 2 reaches the final line (Y in process 105), stop recording control is activated to stop conveyance of the recording paper. That is, FIG. 3S shows the above-mentioned stop recording control pattern, and if line i is the last line, in this case, the signal to the motor drive circuit 4 at the timing of the clock signal Pa is Step pulse S
P and the image of line i is recorded without outputting the increment signal SI to the read pointer 2c at the timing of the clock signal Pc.

FIG. 4 shows the operation in this case. The step pulse SP is not output on line i, but as explained in FIG. Move a little further. Therefore, by applying the drive current Id to the line i at a predetermined timing, a dot image Pi can be recorded as shown in the figure.

After activating such stop recording control, the recording control unit 6 performs a process 108) to determine whether reception of image information is finished.
If reception continues (N in process 108), process 102
Return to

Then, when the image information reaches a certain number of ins or more again, normal recording control is resumed in the same manner as above.

In this case, when recording line i before stopping, the FIFO
Since the increment signal SI is not outputted to the read pointer 2c of the line buffer 2, the same data signal SD of line i is outputted from the FIFO line buffer 2 again, and the image of that line i is recorded again.

Furthermore, in this case, as described with reference to FIG. 6, since this is the first line at the start of recording, that recording line is recorded closer to the line before stopping, and the recording density becomes thinner. However, in this case, as shown in FIG. 4, the dot image P of line 1 recorded before stopping and the dot P1 recorded at the time of restart are recorded at almost the same line position.

For this reason, unlike the conventional method, the line image after restarting recording does not become thin or blank, and a good recorded image can be obtained.

Thereafter, operations are performed in the same manner as described above, and when the reception of image information is completed, a certain number of lines of image information may not be stored in the FIFO line buffer 2.

In this case, (N from process 102, process 103, process 1
03 Y), the image information in the FIFO line buffer 2 is immediately recorded in the same way (proceed to process 104).

After recording the last l line, it is determined that reception has ended (Y in process 108), and the above operations are completed.

Note that in the above embodiment, when the recording operation is stopped, the first line image is recorded at 1 normal density when the recording operation is restarted, but it is also possible to record the image at a slightly lighter density and record it again when the recording operation is restarted. The concentration may be controlled to a normal concentration.

Further, when the first line is to be printed at normal density when restarting when the printing operation is stopped, the I-th line with a lower density may not be printed when restarting.

[Effects of the Invention] As described above, according to the present invention, when the recording operation is interrupted, the first image information to be recorded when the recording operation is resumed is recorded once after the application of the step pulse to the step motor drive circuit is stopped. I decided to keep it.

In addition to being able to record at an appropriate density, the inertia of the step motor and recording paper transport mechanism allows the image information to be recorded at approximately the same line position when stopping and when restarting, resulting in good recorded images. You will be able to get it.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of an image recording apparatus according to an embodiment of the present invention, FIG. 2 is an operational flowchart of its recording process, FIG. 3 is a time chart of each signal, and FIG. 4 is an explanation of the image recording operation. 5 is an explanatory diagram of the drive current to the heating resistor of the thermal head and its temperature, and FIG. 6 is an explanatory diagram of the image recording operation by the conventional image recording apparatus. l...thermal head, la...heating resistor array, lb...driver, lc...latch circuit, ld
...Shift register, 1e...Thermistor, 2...
・FIFO line buffer, 2a...Memory, 2
b...Write pointer, 2c...Continuous pointer,
2d...control unit, 3...stepping motor. 4...Motor drive circuit, -Clock circuit, 6...Recording control section. Figure 2 〇- 〇- Tadashi's 〇- Disease of origin Figure 4 Figure 5 (0) Id Figure 6 Time

Claims (1)

[Claims] By applying recording pulses to the thermal head drive circuit in synchronization with step pulses applied to the stepping motor drive circuit, image information is recorded in the main scanning direction while moving the recording paper in the sub-scanning direction at predetermined intervals. In the image information recording method, when the recording operation is interrupted, the recording pulse is applied only once after the application of the step pulse is stopped to record the image information, while when the recording operation is resumed, the recording pulse applied first is An image information recording method characterized in that the image information recorded at the time of interruption of the recording operation is recorded again.