JPH1188691A - Facsimile equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce missings of information of received data, in the case that a temperature rise in a thermal head is prevented for printing. SOLUTION: This facsimile equipment is provided with a black line detection section 4 which transmits a black line signal, when a ratio of black dots in received data for each line is higher than a setting value, a pattern-generating section 9 which provides an output of a substitute pattern with a low black dot rate, and a data changeover section 5 which provides an output of received data when a temperature of a thermal head 7 does not exceed a high region temperature or no black line signal is sent or provides an output of data corresponding to the substitute pattern, when the temperature of the thermal head 7 exceeds the high region temperature and the black line signal is sent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus for printing received data by using a thermal head, and more particularly to a facsimile apparatus which prints a line having a high black dot ratio when the temperature of the thermal head rises. The present invention relates to a facsimile apparatus that prints with a pattern having a low dot rate.

[0002]

2. Description of the Related Art In a facsimile apparatus using a thermal head, the temperature of the thermal head rises when printing received data having a high ratio of black areas. When the temperature of the thermal head exceeds the upper limit, printing of the received data becomes impossible, and a situation occurs in which the receiving operation is stopped. A conventional technique for preventing such a situation has been proposed as Japanese Patent Publication No. 3-27390. That is, in this technique, when the temperature of the thermal head is lower than a predetermined high temperature range, the energization time to the heating element is changed according to the temperature of the thermal head,
Printing is performed at the same density. When the temperature of the thermal head becomes higher than a predetermined high temperature range, the ratio of the line to be printed is changed to one line to two lines or two lines to three lines in accordance with the degree of the increase. We are thinning out.

[0003]

However, in the case where the above-mentioned conventional technology is used, the following problems have occurred.
That is, it is assumed that the printing of the received data having a high ratio of the black region has continued, and the temperature of the thermal head has exceeded a predetermined high temperature region. In this state, 2
Printing is performed in which lines are thinned out at a ratio of one line to two lines or two lines to three lines. Therefore, when data indicating a character is received following the reception data having a high ratio of the black region, the character is printed by a printing method in which lines are thinned out. Therefore, printed characters are likely to be difficult to read. In the worst case, the characters are unreadable.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image processing method for a line which exceeds a predetermined black dot ratio when the temperature of a thermal head rises. It is an object of the present invention to provide a facsimile apparatus capable of performing printing using a pattern having a low black dot ratio and suppressing a loss of information included in received data when a rise in temperature of a thermal head is suppressed. The object of the invention described in claim 2 is:
Another object of the present invention is to provide a facsimile apparatus capable of performing printing with a reduced ratio of black dots without damaging an image of a black area when received data is data indicating a black area.

[0005]

A facsimile apparatus according to the first aspect of the present invention is applied to a facsimile apparatus for printing received data using a thermal head. When the detected black dot ratio is higher than a predetermined ratio, a black line detection unit that sends out a black line signal and a black dot ratio in one line are detected. A pattern generation unit that outputs an alternative pattern set to a low ratio, and outputs the received data when the temperature of the thermal head does not exceed a preset high-temperature range temperature or when the black line signal is not transmitted, When the temperature of the thermal head exceeds the high temperature range temperature and the black line signal is transmitted, the black line signal is transmitted from the pattern generation unit. A data switching unit for outputting the data corresponding to the alternate pattern that, with the data that the data switching unit outputs has a configuration that includes a print processing unit for driving the thermal head. That is, when the temperature of the thermal head exceeds the high-temperature region temperature, if a line with a high black dot ratio is printed, the temperature of the thermal head may further rise and the operation may be stopped. However, if the received data is a line with a high black dot rate, a black line signal is sent from the black line detection unit, and printing corresponding to the alternative pattern with a low black dot rate is performed. Therefore, a further rise in the temperature of the thermal head is prevented. Further, when the received data is data indicating characters or the like, the black dot ratio does not become the ratio at which the black line signal is output. Therefore, even when the temperature of the thermal head exceeds the high temperature range, if the received data is data having a low black dot rate, such as data indicating characters, the received data is not damaged. Printed.

In a facsimile apparatus according to a second aspect of the present invention, in addition to the above-described configuration, the alternative pattern is a pattern in which the positions of black dots are different from each other in adjacent lines. That is, when the lines from which the black line signal is transmitted are continuous, the positions of the black dots are printed at different positions on adjacent lines. Therefore, on the printed paper surface, the black area is printed as a lighter black area.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration of an embodiment of a facsimile apparatus according to the present invention.

In FIG. 1, a modem 1 is a block for restoring digital data by demodulating an audio signal guided through a telephone line 21. And
Decoding unit 2 decodes the restored digital data (received data)
To send to. The decoding unit 2 is a block for decompressing the received data transmitted from the modem 1 to restore the received data indicating the print image from the compressed received data. Then, the restored reception data is sent to the delay memory 3 and the black line detection unit 4.

The black line detector 4 detects a black dot ratio indicating the ratio of black dots for each line in the received data sent from the decoder 2. When the detected black dot ratio becomes higher than a preset ratio, a block for transmitting a black line signal indicating that the corresponding line is a black line to the switching control unit 11 is provided.
In addition, it is desirable to set the ratio as a criterion for determining whether the corresponding line is a black line to a low ratio in consideration of a temperature rise of the thermal head 7, and to set a high ratio from the printing quality. It is desirable to do. For this reason, in the present embodiment, the ratio serving as the determination criterion is set to 95%, but may be set to another ratio.

The delay memory 3 is a block that gives a delay of one line to the received data sent from the decoding unit 2. Then, the delayed reception data is sent to the a contact of the switch 12 and one of the input terminals of the AND gate 10. That is, the black line detection unit 4
The detection operation of the black dot ratio in is terminated when the reception of the data for one line is completed. On the other hand, the line printed by the thermal head 7 is a line on which the black dot detection by the black line detector 4 has been completed. For this reason,
Regarding the image data sent to the thermal head 7, 1
It is necessary to give a line delay. The delay memory 3 is
It is provided to provide the delay described above.

The pattern generating section 9 is a memory in which an alternative pattern in which the black dot ratio in one line is set to a low ratio is stored in advance.
The signal is sent to the other input terminal of the D gate 10. For details,
As shown in FIG. 2, the pattern generation unit 9 includes an alternative pattern 31 for outputting when the line number to be printed is an even number, and an alternative pattern 32 for outputting when the line number to be printed is an odd number. Are stored. That is, in the alternative pattern stored by the pattern generation unit 9, as apparent from FIG. 2, black dots and white dots appear alternately, and the positions of the black dots on adjacent lines are different from each other. ing. Therefore, the ratio of black dots is 50%.

As another configuration of the pattern generating section 9, for example, a configuration for storing three lines of alternative patterns is used.
A configuration consisting of a combination of two white dots and a configuration in which the positions of the black dots are different from each other in each of the three lines (the ratio of the black dots is approximately 33%);
And so on. Further, since the substitute pattern is a relatively simple pattern, it is also possible to adopt a configuration in which the substitute pattern is generated using software executed by a microcomputer or a logic circuit.

The AND gate 10 is a block for performing an AND operation on the received data delayed by the delay memory 3 and an alternative pattern sent from the pattern generator 9. To send to. More specifically, when the dots of the received data sent from the delay memory 3 are black and the dots of the substitute pattern output from the pattern generation unit 9 are black, dot data indicating black is output. When other combinations are obtained, dot data indicating white is output. Such an AND operation is performed for the following reason. That is, the reference ratio when the black line detection unit 4 determines whether or not the line is a black line is 95%. For this reason, even a line determined to be a black line includes a maximum of 5% of white dots.
Accordingly, the white dots included in the black line of the received data are stored as white dots even in the output of the AND gate 10, and are not changed by the substitute pattern.

The thermal head 7 includes a plurality of heating elements.
The print blocks are arranged in a line in the line direction. The sensor 8 is an element for detecting the temperature of the thermal head 7, and sends a detection output to the switching control unit 11 and the print processing unit 6. The print processing unit 6 is a block that drives the thermal head 7 with a drive signal whose pulse width changes in accordance with the detection output of the sensor 8 in accordance with data transmitted from the contact c of the switch 12. .

The switching control section 11 is a block for controlling the connection of the switch 12 according to the output value of the sensor 8 for detecting the temperature of the thermal head 7 and the black line signal sent by the black line detecting section 4. . That is, the sensor 8
Indicates that the output value does not exceed the preset high temperature range temperature, or when the black line detection unit 4 does not send out the black line signal, the contact c of the switch 12 is set to a.
By connecting to the contact, the received data is sent to the print processing unit 6. In addition to indicating that the output value of the sensor 8 has exceeded the preset high-temperature range temperature, when the black line detection unit 4 sends a black line signal, the switch 1
By connecting the c contact of No. 2 to the b contact, data corresponding to the alternative pattern is sent to the print processing unit 6.

The temperature range in which the thermal head 7 can be used is 70 ° C. or less. For this reason, when the temperature of the thermal head 7 exceeds a predetermined temperature in the range of 60 ° C. to 65 ° C., printing is stopped. For this reason, in the present embodiment, 45 ° C. is adopted as the value of the high temperature range temperature. The high-temperature region temperature can be any other temperature, for example, 50 ° C. or less, such as 60 ° C. or less.

The data switching unit according to the first aspect of the present invention includes a switching control unit 11 and a switch 12. Further, a black line detection unit 4, a switching control unit 11, a switch 12, an AND gate 10, and a print processing unit 6
Is a block mainly composed of software executed by a microcomputer.

FIG. 3 is a flowchart showing a printing operation for each line according to the embodiment, and FIG. 4 is an explanatory diagram showing a relationship between an image indicated by received data and an image to be printed.
The operation of the embodiment will be described with reference to FIG.

The black line detector 4 detects the black dot ratio of the received data of one line each time the reception of the data of one line is completed. When the detected black dot ratio exceeds 95%, the black line signal is switched to the switching control unit 1.
Send to 1. When the detected black dot rate is less than 95%, no black line signal is sent. On the other hand, the switching control unit 11 determines that the temperature of the thermal head 7 is in the high temperature range temperature (4
If the temperature is lower than 5 ° C.), the c-contact of the switch 12 is connected to the a-contact regardless of whether or not the black line signal is transmitted. Therefore, when the temperature of the thermal head 7 is lower than the high temperature range temperature, the print processing unit 6 always has the delay memory 3
The received data output from is derived. As a result, the image indicated by the received data is not changed,
Printing is performed by the thermal head 7 (step S1,
S4).

On the other hand, when the printing of the received data having a high black dot rate continues and the temperature of the thermal head 7 exceeds the high temperature range, when the black line signal is sent out, the switching control section 11 switches the c contact of the switch 12. Is connected to the contact b, and when the black line signal is not transmitted, the contact c of the switch 12 is connected to the contact a. An image to be printed when the connection of the switch 12 is switched as described above will be described with reference to FIG.

Reference numeral 55 in FIG. 4 denotes an image represented by the received data, and an area 51 is a black area composed entirely of black dots. Therefore, the black dot ratio of the received data of each line in the range 57 exceeds 95%. Therefore, when data of each line in the range 57 is received, a black line signal is transmitted each time reception of each line is completed. Therefore, when printing the received data in the range 57, the c contact of the switch 12 is connected to the b contact. That is, the output of the AND gate 10 is guided to the print processing unit 6.

On the other hand, the AND gate 10 outputs the result of an AND operation between the output of the delay memory 3 and the alternative pattern. The alternative pattern is a staggered pattern in which the positions of black dots and white dots alternate between odd lines and even lines. Therefore, the image printed when the data in the range 57 is received becomes the image 53 masked with an extremely minute staggered pattern. That is, the image 53 has the same outline as that of the image 51, and has a hue slightly grayer than that of the image 51 (steps S1 to S3).

When the reception of the data in the area 57 is completed, the data in the area 58 indicating the character is received. The black dot ratio of each line of the reception data indicating the area 58 is low and does not exceed 95%. Therefore, when the data of the area 58 indicating the character is received, the black line detection unit 4 does not send out the black line signal. For this reason,
The contact c of the switch 12 is connected to the contact a. Therefore,
Received data sent from the delay memory 3 is guided to the print processing unit 6. As a result, the printed image is the same as the image indicated by the received data. That is, all the information included in the received data is printed by the thermal head 7 without being damaged, so that the character group 54 to be printed is
Is the same as the character group 52 indicated by the received data (steps S1, S2, S4).

As described above, in the present embodiment, A
An ND gate 10 is provided, and the print processing unit 6 guides the result of an AND operation between the received data and the alternative pattern. Therefore, even in the printing using the substitute pattern, the white dots in the received data are printed as white dots. For this reason, the outline of the black area of the received data is preserved also in the print result. That is, it is possible to perform printing with less loss of information included in the received data.

[0025]

According to the facsimile apparatus of the first aspect, the ratio of black dots for each line in the received data is as follows:
A black line detection unit that sends a black line signal when the ratio becomes higher than a preset ratio; a pattern generation unit that outputs an alternative pattern in which the black dot ratio in one line is set to a low ratio; When the temperature does not exceed the preset high temperature range or when the black line signal is not transmitted, the received data is output, and when the temperature of the thermal head exceeds the high temperature range and the black line signal is transmitted. A data switching unit that outputs data corresponding to the alternative pattern sent from the pattern generation unit, and a print processing unit that drives the thermal head with the data output by the data switching unit. Therefore, when the temperature of the thermal head rises, printing using a pattern with a low black dot ratio is performed only on lines exceeding a predetermined black dot ratio. For lines not exceeding the predetermined black dot rate, printing based on the received data is performed. For this reason, when the temperature rise of the thermal head is suppressed, it is possible to perform printing with little loss of information included in the received data.

Further, in the facsimile apparatus according to the present invention, in addition to the above configuration, the alternative pattern is a pattern in which the positions of black dots are different from each other in adjacent lines. That is, when the lines from which the black line signal is transmitted are continuous, the positions of the black dots are printed at different positions on adjacent lines. Therefore, on the printed paper, the black area is printed as a black area with a lighter color, so that printing with a reduced ratio of black dots can be performed without damaging the image of the black area. It is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of a facsimile apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an alternative pattern.

FIG. 3 is a flowchart illustrating a printing operation for each line according to the embodiment.

FIG. 4 is an explanatory diagram illustrating a relationship between an image indicated by received data and an image to be printed.

[Explanation of symbols]

 4 Black line detection unit 5 Data switching unit 6 Print processing unit 7 Thermal head 8 Sensor for detecting the temperature of thermal head 9 Pattern generation unit 21 Telephone line 51 Black area indicated by received data 53 Printed black area

Claims (2)

[Claims] In a facsimile apparatus for printing received data using a thermal head, a black dot ratio indicating a ratio of black dots for each line in received data is detected, and the detected black dot ratio is set in advance. When the ratio is higher than the ratio, a black line detection unit that sends a black line signal, a pattern generation unit that outputs an alternative pattern in which the ratio of black dots in one line is set to a low ratio, and the temperature of the thermal head is preset When the temperature does not exceed the set high temperature range, or when the black line signal is not sent, the received data is output, and when the temperature of the thermal head exceeds the high temperature range and the black line signal is sent, the pattern is output. A data switching unit for outputting data corresponding to the alternative pattern sent from the generation unit, and an Facsimile apparatus with the data, characterized in that a print processing unit for driving the thermal head. 2. The facsimile apparatus according to claim 1, wherein the substitute pattern is a pattern in which positions of black dots are different from each other in adjacent lines.