JPS58173968A - Heat sensitve recording method - Google Patents

Abstract

PURPOSE:To improve the picture quality, by recording adjacent two lines with data set once in a shift register and attaining continuous printing between the lines in performing the rewrite. CONSTITUTION:The 1st picture signal 21A is set over 3mS time from a time t0 to a shift register driver 4. The recording corresponding to each bit is done sequentially and the 4th drive signal 18-4 is generated over 1mS time from a time t5. Thus, a step motor 17 is driven forward for one line's share and the recording position of the (n+1)th line ln+1 of the recording paper arrives beneath the heater 1. Then, in each recording position, the recording corresponding to each bit of the 2nd picture signal 21B is done. In this case, the recording is done continuously even on the way of moving of the recording paper, and the recording for two-line's share is all finished. The time required for the recording of two-line's share is 10mS, which is short remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording method for performing thermal recording using a thermal head, and more particularly to a thermal recording method in which image information for each line is written twice by overlapping scanning.

For example, in a thermal recording device used in a facsimile, a thermal head is driven by an image signal sent using the rask scan method, and heat pulses are supplied to thermal recording paper or thermal transfer recording paper to perform thermal recording. ing. In such a thermal recording apparatus, when performing enlarged recording or when the scanning line density on the reading side of the document is coarse, image information for each line may be written twice by overlapping scanning.

FIG. 1 shows the main parts of a thermal recording device that performs such double writing. One heating element 1 is arranged in the thermal head of this device.

Two types of lead wires 2 are attached to the heating element 1 at a predetermined interval.
, 3 are connected alternately. The other end of one of the lead wires 2 is connected to each parallel signal output terminal of the shift register driver 4. Further, the other lead wire 3 is alternately connected to the first common electrode 6 or the second common electrode 6 through the correspondingly provided diodes 5.
are commonly connected to the common electrode 7 of the two. A voltage is applied to the first common electrode 6 from a power supply 12 via a first switch circuit 11 operated by a first common drive signal 9 output from a double writing control section 8. There is. Similarly, a voltage is applied to the second common electrode 7 via a second switch circuit 14 operated by a second common drive signal 13. The double writing control unit 8 feeds the paper! IItill signal 15 to motor drive circuit 16
It is designed to be supplied to As a result, the drive signal 1 is supplied from the motor drive circuit 16 to the step motor 17.
8 is controlled, and the running of recording paper (not shown) is controlled.

When the double writing control unit 8 of this thermal recording device receives the image signal 21 for one line, the image information is divided into mutually complementary first and second bits intermittent in a comb-like manner every 2 bits. image signals 21A and 21B are created.

First, the first image signal 21A is output as serial data from the twice-write control section 8, and is set in the shift register driver 4. For example, the time required for setting
As shown in Figure a, 3m5 (milliseconds) is how long. While the data set is being performed, the drive signal 18 is e.g.
This occurs over ms (Fig. 2). This causes the recording paper to advance by one line. Once the dataset is finished,
For example, the first common drive signal 9 is generated during the third period (Fig. 2C), and the first common drive signal 9 is generated during this signal generation time.
A voltage is applied to. As a result, two heating elements are divided by each lead wire 2 and 3 on the heating element 1 (one at each end).
2) is driven, and thermal recording corresponding to half of one line is performed.

When this recording operation is completed, the second write control unit 8 sends the second
The image signal 21B is output as serial data.

The second image signal 21B similarly takes 3 ms to be set in the shift register driver 4 (FIG. 2a).

When the data set is finished, a second common drive signal 13 is generated during IIs (FIG. 2d). During this signal generation time, a voltage is applied to the second common electrode 7, and the remaining heating elements on the heating element 1 are driven. Thermal recording corresponding to the remaining half of one line is thereby performed.

When the recording operation for one line is completed in this way (3-), the same operation as described above is repeated, and one more line is recorded using the same image information. That is, the first image signal 21A is reset in the jitter register driver 4 for 3 ms, and at this time the recording paper advances by one line by the drive signal 18. After that, half of one line is recorded, and then the second image signal 21B is reset, and the remaining one line is recorded. After such a recording operation is performed, the double write control section 8 receives the image signal for the next one line.

As described above, in the conventional thermal recording method when writing twice, data is set in the shift register and the heating elements are are measured alternately. Therefore, in the example given above, the recording time required for writing twice is 4 in total.
However, the time required to set the data was three times that amount, 12n+S, making the overall time required longer at 16m5. If the time required for writing twice in this way is long, efficient transmission of image information cannot be carried out. Furthermore, since the driving cycle of the thermal head becomes longer, it is necessary to preheat the thermal head more than necessary or to increase the time for each heating element to be energized at low temperatures, resulting in the problem of wasted power consumption.

The present invention has been made in view of the above circumstances, and is designed to reduce the data set required for double writing in a recording device that prints one line in two cycles by driving the heating element of the thermal head every two dots at a time. It is an object of the present invention to provide a thermosensitive recording method that can shorten the sum of time.

In the present invention, the above-mentioned object is achieved by recording two lines using data set once in the shift register.

The present invention will be described in detail with reference to Examples below.

FIG. 3 shows the thermal recording method of this embodiment in double writing. In this method, the first image signal 21A is set to the shift register driver 4 shown in FIG. 1 over a period of 3IllS from time t, as shown in FIG. 1A. The first drive signal @18-1 is generated from the motor drive circuit 16 for 1 ms from the start time [, of this data set] (FIG. 3b). As a result, the step motor 917 advances by one line, and the recording position of the nth line β1 (n is an arbitrary integer) of the recording paper reaches directly below the heating element 1.

When the datalets of the register driver 1 to the register driver 4 are completed, the double write control unit 8 generates the first common drive signal 9 (FIG. 3C) during the time period [1 to 2ilS]. The first switch circuit 11 is thereby turned on, and a voltage is applied to the first common electrode 6. Along with this, the fourth
At each recording position indicated by diagonal lines 31 in FIG. 1A, recording is performed in accordance with each bit of the first image signal 21A.

1111S from time t2 during this recording
As a result, a second drive signal 18-2 is generated (FIG. 3b). As a result, the step motor 17 is driven by one line, and the recording position of the 0+1st line βη+1 on the recording paper reaches directly below the heating element 1. At the same time, at each recording position already indicated by diagonal lines 32 in FIG. 4, recording is similarly performed in accordance with each bit of the first image signal 21A. In this case, the recording paper is from the n-th line β1 to the n+1-th line β
Selective driving of the heating element 1 is continuously performed even during the movement to η+1. Therefore, thermal recording is performed at these locations as well, but it goes without saying that this does not cause any inconvenience.

The first image signal 2 is output at time t3, which is 2 mS after time t1.
When the recording for 1A is completed, the data set of the second image signal 21B (FIG. 3a) is performed for 3 ms from this time. With the start of this dataset, 11
IISkl: Third drive signal 18-3 (b in the same figure)
occurs. The third drive signal @18-3 is a drive signal for reverse rotation, and the step motor 17 is driven in the reverse direction for one line (the recording position of the nth line β1 on the recording paper is directly below the heating element 1). □ When the data set of the second image signal 21B is completed at time [4], the double-write control unit 8 generates the second common drive signal 13 during 211IS from now on (Fig. 3). d).The second switch circuit 14 is thereby turned on, and a voltage is applied to the second common electrode 7.At the same time, at each recording position indicated by diagonal lines 33 in FIG. Recording is performed according to each hit of the signal 21B.

During this recording, the fourth drive signal 18-4 is generated over 11 seconds from time t5, as shown in FIG. 3b.
). As a result, the step motor 17 is driven in the forward direction by one line, and the recording position of the 0+1st line βη+1 on the recording paper reaches directly below the heating element 1. Along with this, the fourth
At each recording position indicated by diagonal lines 34 in FIG. d, recording is similarly performed according to each bit of the second image signal 21B.

Of course, in this case, recording is performed continuously even during the movement of the recording paper. In this manner, recording of two lines is completed. The time required to record two lines in this example is 10IllS as shown in FIG.
It can be seen that the time is significantly shortened compared to the conventional example of 161118.

As explained above, according to the present invention, when writing twice 8-, two adjacent lines are recorded using the data that has been once written to the shift register, so there is no continuous data between these lines. It is possible to perform high quality printing and improve the image quality.

In the embodiment, two lines of the same image information were recorded by continuously energizing the heating element, but by controlling the first or second switch circuit 13 or 14 connected to the power supply,
Of course, printing may be interrupted between each line.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the electrical circuit of a thermal recording device that performs double writing, Fig. 2 is a timing diagram for explaining a conventional thermal recording method, and Fig. 3 is an embodiment of the present invention. FIG. 4 is an explanatory diagram for explaining temporal changes in printing in this embodiment. 4...Shift register driver 8...
・Double writing control unit 17...Step motor Figure 2 Haruma Kyu 3 Figure t. Figure 4

Claims (1)

[Claims] In a recording device that divides one line of serial data to be recorded into halves, sequentially sets each piece of data in a shift register, performs serial-to-parallel conversion, and then prints.
When performing overlapping recording of two lines using one line of data, first store the first half of the data of one line in a shift register, perform overlapping recording of two lines using parallel signals based on this, and then scan. A thermal recording method characterized by returning the line to the beginning, storing the remaining half of the data in the shift register, and performing redundant recording of the remaining two lines using parallel signals based on this data.