JPS616981A - Heat sensing recorder - Google Patents

Abstract

PURPOSE:To decompose correctly a line picture while keeping a saturated density of a printed picture high by changing the size of a print dot depending on whether the print pattern is the line picture or not and printing the result. CONSTITUTION:The titled recorder consists of a line picture judging section deciding whether a recording signal R is the line picture or not while receiving the signal R, a print energy arithmetic unit 3 controlling a drive energy quantity fed to a thermal head 2 with the signal from the discriminating section and a thermal head drive circuit 4 driving the head 2 through the reception of an output signal from the circuit 3. Then the judging section 1 outputs a signal suppressing the print energy to a small value for the line picture only to the circuit 2 and the circuit 2 outputs a value reducing the print energy by a prescribed value to the circuit 3. Thus, the thermal energy fed to an ink doner film is reduced and the size of dot is decreased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal recording device, and in particular to a thermal recording device that can visually accurately record minute patterns such as thin lines or small Chinese characters with many strokes. Regarding.

[-Prior Art] With the spread of Japanese word processors, there is an increasing demand for recording devices such as printers that are capable of recording kanji characters.

For one, attempts have been made to record kanji using transfer type thermal recording devices. Transfer-type thermal recording devices use a thermal head to selectively heat a thin film such as capacitor paper or polyester coated with heat-melting ink, melting the ink in the heated areas and transferring it onto recording paper for recording. This is a device that performs By the way, the saturation density of a recorded image is determined by the content of pigments such as carbon in the ink, but usually the pigment content is such that the optical density of printed solid black (full dots) is about 1.0 to 1.3. ink is used. This type of ink can print a simple pattern appropriately, but if you try to print a kanji character with a large number of strokes in a small space of about 3 mm square, for example, the kanji character itself will not be correctly resolved and printed. However, the ink density was so high that it visually appeared crushed, and although it was legible, its use as a document was questionable.

The above-mentioned problem occurs not only when printing kanji characters but also when printing thin lines, and it is impossible to avoid the inconvenience that the printing appears thicker than it should actually be printed.

One measure to solve these problems is to reduce the pigment content of the ink, but in that case, there is a problem that the saturation density of full-dot printing is reduced.

[Problems to be solved]

The present invention has been made to solve the above-mentioned problems, and while maintaining a high saturation density of the printed image, it also visually collapses complex line images such as fine lines and small kanji patterns with many strokes. It is an object of the present invention to provide a heat-sensitive recording device that can accurately resolve images without any problems.

[Means for solving problems]

The thermal recording device of the present invention includes a line image determining means for determining whether a recorded image is a line image, and a printing energy control means for adjusting the size of a printed dot based on the determination result. Equipped with

[Effect]

With this configuration, in the present invention, the size of the print dots is changed depending on whether the print pattern is a line image or not, so that the line image can be correctly resolved while keeping the saturation density of the print image high. It becomes possible to image.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a transfer type thermal recording apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, this transfer type thermal recording apparatus includes a line image determining section 1 that receives a recording signal R and determines whether or not the recorded signal represents a line image; Part 1
a printing energy calculation circuit 2 that controls the amount of drive energy supplied to the thermal head 2 in response to a determination signal from the thermal head 2;
and a thermal head drive circuit 4 configured to drive the thermal head 2 in response to a signal carrying print energy information from the print energy calculation circuit 3.

Here, the recording signal R is obtained by identifying in advance in a reading section (not shown) whether or not the inputted printing signal P is a line image as a printing signal P carrying information to be recorded.
It is composed of identification signals transmitted as ON-OFF signals by changing the dip switch, and the line image judgment section 1 receives the identification signal 1 among these signals and determines whether the identification signal 1 is ON. A signal is outputted to the printing energy calculation circuit 2 only when the printing energy is kept small.

The printing energy calculation circuit 2 calculates the printing energy value to be supplied to each heat generating resistor only when it is confirmed that the line image is a line image based on the judgment information output from the line image judgment unit 1, using the printing signal P. The calculated value is calculated so as to be reduced by a predetermined value from the value obtained by , and is output to the thermal head drive circuit 3 .

Then, in the thermal head drive circuit 3, the printing energy of the value calculated by the above-mentioned means is outputted to each heating resistor, and the printing energy calculated to be smaller is outputted to the line image. Therefore, the thermal energy supplied to the ink donor film is also reduced. Therefore, the size of the dots becomes smaller and fine line images are printed with good resolution.

In this way, a fine line image can be printed with good resolution without reducing the saturation density of the printed image.

Note that the print signal may be provided from the outside, as in the case of a printer, or may be generated by reading a document within the apparatus, as in a copying machine.

Next, other embodiments of the present invention will be described.

As shown in FIG. 2, in a transfer type thermal recording device according to another embodiment of the present invention, an image is transmitted from an image input unit A (external) of a facsimile or the like through an interface, or is transmitted to the inside of a device such as a copying machine. a line memory 11 for receiving the recording signal R' carrying the image information on the manuscript by the disposed manuscript reading system B and storing recording data from the first row to the Nth row; A memory section includes an M-stage shift register 12 into which data read out from each line of the line memory 11 is input, and printing is performed from the print pattern information of MXN dots around the dot of interest obtained by the shift register 12. A line image recognition circuit 13 comprising a ROM 1 configured to calculate whether or not a dot of interest constitutes a line image, output data from the recorded image recognition circuit 13, and output data from the shift register 12. A printing energy calculation circuit 15 comprising a ROM 2 configured to calculate the printing energy to be applied to the heating resistor of the thermal head 14 from the recording signal of the noted dot, and printing energy information calculated by the printing energy calculation circuit 15. The thermal head drive circuit 16 supplies power to drive the heating resistor based on the thermal head drive circuit 16.

Note that when m x n areas including the printed dot of interest are printed and other areas are not printed, the line image recognition circuit 13 determines that the dot of interest is part of a kanji character, and also determines that the dot of interest is part of a kanji character. When the print information of the dot of interest and the print information immediately before it are both printed, and other adjacent dots are not printed, the dot of interest is determined to be part of a thin line. If it is determined that it is part of a kanji character or a thin line, the printing energy calculation circuit will:
The printing energy to be supplied to the corresponding heating resistor is calculated from the recording signal of the noted dot so that it is smaller by a predetermined amount than in the case otherwise.

For example, as shown in FIG.
FIG. 4 shows an example in which information corresponding to peripheral pixels Ao-Ag for five lines can be stored.

The storage unit includes a first line memory 31 and a second line memory 32, which are connected in series to each other, in order to sequentially input and store recording signals R' input from an external source or a document reading system. A first shift register 33 which sequentially inputs five stages of signals Ao-A4 from a first line memory and outputs them simultaneously;
It is composed of a second shift register 34 which sequentially inputs the signals of five stages A5 to A8 from the second line memory 32 and outputs them at the same time, similar to the register. ) Centered on A? Information for 2 rows and 5 stages of C is read out from the RoMH. At this time, R
In OM1, if the information is such that only the 2x3 pixels surrounded by the mouth are printed, and the rest are not printed, as shown in Figure 3 of the 2x5 strokes, the dot A7 of interest is a part of the kanji. Also, as shown in FIG. 3 (2X3), only the adjacent pixels on the same line and/or the same column (pixels corresponding to the dot of interest in the previous row) of the dot of interest are printed, and the others are not printed (! : It is determined that it is part of the #l line.

The thermal head drive circuit controls the printing energy applied to each heat generating resistor of the thermal head, and drives the heat generating resistor by keeping the terminal voltage applied to the heat generating resistor constant and controlling the energization time. That's what I do.

In this way, since the printing energy is adjusted, a fine line image can be printed in a good resolution state without reducing the saturation density of the printed image.

In ROM1, since it is possible to know the print data of pixels surrounding the pixel of interest, a function is added here to calculate the heat storage state of the printed dot of interest, and a heat storage correction is also performed in the print energy calculation circuit of ROM2. It is also possible to perform printing that is more faithful to the image information than 1ζ.

In addition, the printing energy calculation circuit of It OM 2 may be further provided with a correction function according to the temperature of the substrate of the thermal head, a correction function for correction of variations in Conergies due to variations in the individual resistance values of heating resistors, etc. .

Additionally, the thermal head drive circuit may be implemented.

[Effects] As described above, the transfer type thermal recording device of the present invention includes a line image determining means for determining whether a recorded image is a line image, and a line image determining means for determining whether a recorded image is a line image, and a printing dot based on the determination result. Equipped with a printing energy control means that adjusts the size of the print image, it is possible to maintain a high saturation density of the printed image while also visually correctly interpreting fine patterns such as thin lines and small kanji with many strokes. can be imaged.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a transfer type thermal recording apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a transfer type thermal recording apparatus according to another embodiment of the present invention. FIG. 3 is a diagram showing the relationship between the pixel of interest and surrounding pixels, and FIG. 4 is a diagram showing a specific example for explaining the apparatus shown in FIG. 2 in more detail. 1. Line image judgment section, 2. Thermal head, 3. Print energy calculation circuit, 4. Thermal head drive circuit, R recording signal, P-print signal, D.- identification signal, A. Image input section, B... - Original reading system, R...Record signal, Etline memory, 12 Shift register, 13 Line image recognition circuit, 14...Thermal head, 15. Print energy calculation circuit, 16. Thermal head drive circuit, 31
...First line memory, 32.. Second line memory, 33.. First shift register, 34.. Second shift register.

Claims (1)

[Claims] Printing energy is applied to the heating resistor of the thermal head in accordance with the recorded information to selectively generate heat, and the heating resistor is brought into sliding contact with a recording paper overlaid on a thermal recording paper or an ink donor film to perform recording. The thermal recording device according to the present invention includes a line image determining means for determining whether or not a recorded image is a line image, and a printing energy control means for adjusting printing energy based on the determination result. Features of thermal recording device.