JPS63199648A - Recording method in printer - Google Patents

Abstract

PURPOSE:To conduct a recording with a high resolving power and a fidelity to an original image, by a method wherein a sampling cycle is made 1/n that in normal recording, a dot pitch is also made 1/n, and a recording element driving energy is made smaller than that in normal recording. CONSTITUTION:For a high-resolving power recording, a sampling frequency is turned to 2f by a switch 3, i.e. to be twice that in normal recording and, thereby, the recording element driving pulse width turns to t2 shorter than that in normal recording and a recording paper feed pitch turns to d/2. Therefore, the sampling of input signal is carried out with a frequency 1/2 that in normal recording, and the sampling data is stored in a memory 4. In synchronism with the read of the data, a recording element 7 is driven with a pulse of t2 width. After the recording of one dot, a recording paper is fed with a pitch d/2 by a paper feed motor drive circuit 10, and a recording is conducted with a pulse of t2 width. In this manner, the dot pitch is to be d/2, and a high- resolving power recording is performed with dots twice as many as those in normal recording and the same size as that in normal recording.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a recording method for a printer.

[Prior Art] For example, in a thermal line printer that records a hard copy of a television screen, in order to double the horizontal resolution, the sampling period of the image signal is halved and the image signal is recorded at the same pitch as normal recording. There is something that does this.

[Problems to be Solved by the Invention] In the above method, the horizontal direction is recorded with twice the number of samplings as the vertical direction, and the print screen is twice as wide in the horizontal direction, making it impossible to obtain a hard copy that is faithful to the original image. was something that could not be obtained.

The present invention enables high-resolution recording that is faithful to the original image.

[Means for solving the problem] The present invention reduces the sampling period to 1/n (n
>l), the dot pitch is also set to 1/n, and the driving energy of the recording element is made smaller than that during normal recording.

[Embodiment] In FIG. 1, reference numeral 1 denotes a sampling circuit, which samples an input signal such as a television image signal. 2
3 is a sampling period switching circuit, and 3 is a switching switch thereof. 4 is a memory for one column of sampled recording data, and 5 is W for controlling data writing and reading.
/R control circuit. The read clock for this W/R control circuit 5 is supplied from a CPU or the like (not shown). Reference numeral 6 indicates a drive circuit for the recording element 7, which is a thermosensitive element; 8, a pulse width control circuit that controls the drive pulse width of the recording element 7; 9, a feed pitch control circuit that controls the feed pitch of the recording paper; and 10, a paper feed motor. This is a drive circuit.

Next, the operation will be explained. First, the operation for normal recording will be explained. In this case, the switch 3 selects the sampling pulse of frequency f. At the same time, this switch operation changes the drive pulse width of the recording element to the third
It is set at t as shown in the figure. Also, the feed pitch of the recording paper is d as shown in Figure 2.
is set to

Therefore, the input signal is sampled using the sampling signal, and this sampling data is sequentially written into the memory 4. In this sampling, samples are taken one column at a time in the vertical direction from the left end of the television screen. When one column of data is written, W/
A read signal is supplied to the R control circuit 5, and data is read from the memory 4. In synchronization with this reading, the pulse width control circuit 8 generates a pulse having a width t1 shown in the third diagram, and the recording element 7 is selectively driven. When one dot is recorded as shown in FIG. 2, the paper feed motor drive circuit 10
The recording paper is fed by pitch d.

By repeating the above operations, the dots D are sequentially recorded as shown in FIG. 2, and normal recording is performed.

Next, the operation when performing high resolution recording will be explained. In this case, the switch 3 switches the sampling frequency to 2f, twice that of normal recording. At the same time, this switch operation changes the driving pulse width of the recording element to the sixth
As shown in the figure, the time is changed to t2, which is shorter than that during normal recording. Further, the feeding pitch of the recording paper is switched to d/2 as shown in FIG.

Therefore, the input signal is sampled at half the normal cycle, and this sampling data is stored in the memory 4. In synchronization with this data reading, the recording element 7
is driven by a pulse of width t2 in FIG. Since this pulse width is shorter than normal, the dot density distribution at this time is as shown in FIG. 7, and the spread of the dots is suppressed. The meaning of this will be explained later.

Now, once one dot has been recorded as described above, the paper feed motor drive circuit 10 feeds the recording paper at a pitch d/2, which is half the normal pitch. Thereupon, data of the next column is sampled, and recording is performed using a pulse having a pulse width t2 in the same manner as above. Therefore, the pitch of the dots is d/2 as shown in FIG. 5, and high-resolution recording is performed with twice the number of dots as in the normal case at the same size as in the normal case.

By the way, under normal conditions, the recording element is driven by the pulses shown in FIG. 3, and the dot density distribution at that time is as shown in FIG. 4. Therefore, if the dot pitch is reduced to 1/2 and driving is performed with the same pulse width as above, adjacent dots will overlap, and this overlap will have a high density, making it impossible to obtain high resolution. .

In this example, when the dot pitch is reduced to 1/2, the pulse width is narrower than normal to narrow the dot density distribution, and by reducing or eliminating the overlap between adjacent dots, independent dots can be recorded. year,
This allows for high-resolution recording. Incidentally, it is preferable to set the pulse width so that the maximum density of the overlapping portion of adjacent dots is about 0.4 in optical reflection density.

Note that in the above embodiment, the driving energy of the recording element is controlled by the pulse width, but the invention is not limited to this.
Control may also be performed using drive voltage, drive current, or the like.

Furthermore, in the above example, the sampling period was set to 1/2 and the dot pitch was set to 1/2, but the invention is not limited to this. If the sampling period is set to 1/n (n>1), the dot pitch is set to 1/2. It may be set to 1/n.

Further, the present invention is not limited to thermal printers, but can be applied to any printer that performs dot recording, regardless of whether it is a line printer or a serial printer.

[Effects of the Invention] According to the present invention, high-resolution recording faithful to the original image can be obtained without using a high-resolution recording head.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing an example of dots by normal recording, and Fig. 3 shows pulses for recording the dots shown in Fig. 2. 4 is a density distribution diagram showing the density distribution of the dots in FIG. FIG. 7 is a pulse waveform diagram showing pulses for recording, and FIG. 7 is a density distribution diagram showing the density distribution of the dots in FIG. 1... Sampling circuit 2... Switching circuit 4... Memory 6... Drive circuit 7... Recording element 8... Pulse width control circuit 9... Feed pitch control circuit D... Dot that's all

Claims (1)

[Claims] In a printer that sequentially supplies recording data obtained by sampling an input signal at a predetermined cycle to a recording element, and records dots while shifting the relative position of this recording element and recording paper, the sampling cycle of the input signal is normally recorded. When the dot pitch is set to 1/n (n>1), the dot pitch is set to 1/n.
A recording method for a printer, characterized in that the driving energy of the recording element is lower than that during normal recording.