JPH0375897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a hard copy device that takes a hard copy of a still image displayed on a CRT display device or the like.

"Prior art" Generally, computer output devices include:
Although CRT (cathode ray tube) display devices are widely used, the images displayed on these display devices are temporary, so hard copy devices have been developed that print these images on paper. For example, from a display device with a display function of 512 x 256 dots as shown in Figure 4A,
Along with the horizontal and vertical synchronization signals, the scanning line S ₁
512 dots of video data are sequentially supplied corresponding to each of the steps S256 to _S256 . Therefore, when making a hard copy of the display screen G of this display device, first, the video data for 512 dots of the first scanning line _S1 is loaded into the buffer memory, and then the video data is read out from this buffer memory. Based on this read video data, the thermal head ₁₂ of 512 dot lines shown in FIG. Perform thermal transfer of (1, 512). Thereafter, the paper 13 is sent out in the direction of arrow F by one line. Next, the video data for 512 dots of the second row of scanning lines _S2 is loaded into the buffer memory.
Driving the thermal head 12, the pixels P in the second row
Thermal transfer of (2, 1) to P (2, 512) is performed. The thermal transfer operation for one line and the breaking operation for one line are combined into one
By repeating frames, that is, 256 times,
The image on the display screen G of the display device is thermally transferred onto the paper 13 to make a hard copy.

"Problems to be Solved by the Invention" Incidentally, in recent years, efforts have been made to increase the resolution of CRT display devices, and for example, high-resolution display devices having a display function of 1280×1024 dots have been developed. When making a hard copy of the display screen of this high-resolution display device using the conventional hard copy device described above, the conventional hard copy device has a printing capacity of only 512 x 256 dots, so the print capacity is 1280 x 1024 dots. It is not possible to print the entire display screen at once. Therefore, it is necessary to divide the display screen of the display device into several parts and make a hard copy for each divided display screen.To do this, any area on the display screen must be designated as the print area. functionality is required. However, in conventional hard copy devices, when specifying the print area, it is necessary to change the settings of a depth switch mounted on the printed circuit board inside the device, which makes it difficult to specify the print area. Nakatsuta. Also,
Some models have setting values written in ROM (read-on memory) instead of a depth switch, but in this case, in order to change the print area,
I have to replace the ROM. It is extremely difficult to select and use only the data corresponding to the desired print area from among the video data that is serially output from the display device.
There has never been a hard copy device capable of this.

This invention has been made in view of the above-mentioned circumstances, and is useful when making a hard copy of a portion of the display screen of a high-resolution display device where the number of display dots per line is greater than the number of printable dots per line. To,
It is an object of the present invention to provide a hard copy device in which a desired area (within a range corresponding to the number of printable dots) on the display screen can be easily designated as a print area.

"Means for Solving the Problem" A printing head with a printable number of dots per line smaller than the number of display dots for one line of a display device, and a storage capacity corresponding to the number of printable dots. a buffer memory; a print area designating means that is operable from the outside of the device and designates any area on the display screen of the display device within a range determined by the number of printable dots as a print area; and the display device The start point of the horizontal dot range corresponding to the print area on the display screen is generated as the writing start dot specified value, and the number of the horizontal scanning line belonging to the line range corresponding to the print area is written. The line specification values are generated sequentially, and each time the writing of the video data to be printed in the buffer memory is completed, the printing control for one line is performed to drive the printing head according to the data in the buffer memory, and the paper is A first control means for controlling paper feed to feed one line, and counting the number of horizontal scanning lines corresponding to video data currently being output from the display device based on a synchronization signal output from the display device. , when the count value matches the specified write scanning line value at the time, a predetermined number of dots are added starting from the dot position corresponding to the write start dot specified value in the video data output from the display device. The present invention is characterized by comprising a second control means for selecting video data corresponding to the exceeded dot range and writing it into the buffer memory as the video data to be printed.

"Operation" By specifying a desired area on the display screen of the display device as a print area by the print area designation means, video data corresponding to this print area is generated under the control of the first and second control means. are written into and read from the buffer memory. Then, by driving the print head based on the read video data, a portion of the print area is printed on the paper, and a hard copy of the desired area is made.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.

In this embodiment, as shown in Fig. 2A,
A case will be described in which a hard copy of a portion of the display screen HG of a high-resolution display device having a display function of 1280×1024 dots is made. This display device uses 1024 scanning lines S ₁ to S ₁₀₂₄ for one screen HG.
and each scanning line S ₁ to S ₁₀₂₄ is composed of 1280 pixels each.
It is made up of dots. It is also assumed that a horizontal synchronizing signal HS, a vertical synchronizing signal VS (both low active), and video data VD are output.

In Figure 1, 1 is a CPU (central processing unit),
2 is a ROM in which a hard copy program used by the CPU 1 is stored; 3 is a RAM (random access memory) for temporarily holding data used while the above program is being executed; these are interconnected by a bus line 4. has been done. Reference numeral 5 denotes a digital switch for setting a printing area PE, which will be described later. This digital switch 5 and a mechanism section 6 consisting of a paper feed motor, etc. are connected to the bus line 4 via an I/O interface 7. . In this case, the digital switch 5 is placed at a position where it can be easily operated from outside the device. Reference numeral 10 denotes a buffer memory having a storage capacity capable of storing 512 dots worth of video data VD, that is, a storage capacity of 512×bits, and the video data VD read from this buffer memory 10.
is supplied serially to the thermal head drive circuit 11 one dot at a time. The thermal head drive circuit 11 includes a shift register made up of 512 flip-flops, and a gate circuit that controls opening and closing of each output signal of these shift registers based on a print command PS supplied from the CPU 1. The output signal is supplied to each heating element of the thermal head 12, which has 512 heating elements arranged in a straight line.

Reference numeral 15 designates a write scanning line specifying circuit for specifying the video data VD to be written into the buffer memory 10 for each scanning line S ₁ to S ₁₀₂₄ . A data latch 16 that latches the scanning lines S1 to S1024 (corresponding to scanning lines _S1 to S1024 shown in FIG. Setting value latched in data latch 16 and counter 17
and a comparator 18 which supplies an "H" level signal to the first input terminal of the AND gate 19 when the count value of the AND gate 19 matches the count value of the AND gate 19. A horizontal synchronizing signal HS is supplied to the clock input terminal CK of the counter 17, and a vertical synchronizing signal VS is supplied to its clear input terminal CLR.

20 is a write pulse generation circuit that generates a write pulse HCLK of a constant frequency synchronized with the horizontal synchronization signal HS;
HCLK is supplied to the second input terminal of the AND gate 19, the write terminal WR of the buffer memory 10, and a write start dot designation circuit 22, which will be described later.
The write start dot designation circuit 22 is for designating the number of dots from the beginning of one line of video data VD, that is, 1280 dots of video data VD, to be written into the buffer memory 10.
A data latch 23 that latches the set value set by the CPU 1, a counter 24 that counts the write pulse HCLK, and a data latch 23.
A comparator 25 outputs a "H" level signal when the set value latched in the counter 24 matches the count value of the counter 24, and a horizontal synchronizing signal HS falls to detect the "H" level output signal of the comparator 25. The D-flip-flop 26 holds the data for a period of up to 30 seconds. In this case, the write pulse HCLK output from the write pulse generation circuit 20 is supplied to each clock input terminal CK of the counter 24 and the D flip-flop 26, and the horizontal synchronization signal HS is supplied to each clear clock input terminal of the counter 24 and the D flip-flop 26. They are respectively supplied to the input terminal CLR. Further, the output terminal of the D flip-flop 26 is connected to the pre-reset input terminal PR, and the Q output terminal is connected to the third input terminal of the AND gate 19.

When the output signal of the comparator 18 and the Q output of the D flip-flop 26 are both at "H" level, the write pulse HCLK output from the write pulse generation circuit 20 is
9 to the clock input CK of the address counter 28, and is counted by the address counter 28. The count value of the address counter 28 is sent to the address end of the buffer memory 10 via the multiplexer 29 as a write address.
The video data VD of the scanning lines S ₁ to _{S 1024} corresponding to the set value set in the data latch 16 by the CPU 1 are sequentially supplied to the AD, and as a result, the video data VD of the scanning lines S 1 to S 1024 corresponding to the set value set in the data latch 23 by the CPU 1 are From there, one address is assigned to each dot and sequentially stored in the buffer memory 10.

On the other hand, 30 is an address latch that latches the read address set by the CPU 1, and the read addresses sequentially set in this address latch 30 are supplied to the address end AD of the buffer memory 10 via the multiplexer 29.
As a result, the data stored in the buffer memory 10 is
512 dots of video data VD is output at the data output terminal.
One dot at a time is serially supplied from the DO to the thermal head drive circuit 11.

Here, the CPU 1 selects the write scanning line designation circuit 15.
The setting value initially set to the data latch 16 in
The setting value that CPU1 finally sets in the data latch 16 in the write scanning line designation circuit 15, CPU1
The set value set in the data latch 23 in the write start dot designation circuit 22 and the read address finally designated by the CPU 1 to the buffer memory 10 can be arbitrarily designated by the digital switch 5. That is, the CPU 1 reads four types of specified values specified by the digital switch 5, and determines each of the above-mentioned setting values according to these specified values.

Next, the operation of the hard copy apparatus according to the embodiment described above will be explained with reference to the timing chart shown in FIG.

Here, from the 1280 x 1024 dot display screen HG of the display device as shown in Figure 2A,
The print area PE is a 512 x 256 dot area whose horizontal direction is represented by dots 101 to 612 and whose vertical direction is represented by scanning lines S ₁₀₁ to S ₃₅₆ .
This will be explained using an example of specifying ``as'' and taking a hard copy.

First, before making a hard copy, the specified value ``101'' corresponding to the scanning line S <sub>101</sub> where printing starts, the specified value ``101'' corresponding to the horizontal dot where printing starts, and the scanning line where printing ends. Four types of designated values are designated by the digital switch 5: a designated value "356" corresponding to _S356 , and a designated value "612" corresponding to the horizontal dot at which printing is to be completed.

When the start button (not shown) is pressed after the above specification of the print area PE is completed,
The CPU 1 sets the data latch 16 in the write scanning line designation circuit 15 to "100" and sets the data latch 23 in the write start dot designation circuit 22 to "100".

The counter 17 counts the number of times the horizontal synchronizing signal HS rises after the vertical synchronizing signal VS rises, and this count value is the third
As shown in figure b, number 1 of scanning line S ₁ ~S _{1024 ~}
1024 respectively. And counter 17
When the count value reaches "100", the output of the comparator 18 becomes "L" as shown in FIG.
The level becomes "H" level, and then returns to "L" level again when the count value reaches "101".

On the other hand, count 24 is the write pulse HCLK supplied from the write pulse generation circuit 20 after the horizontal synchronization signal HS rises.
The number of pulses is counted, and this count value corresponds to the number of dots in each scanning line. And every time the count value of count 24 becomes "100",
As shown in FIG. 3d, the output of the comparator 25 becomes "H" level. The "H" level output signal of the comparator 25 is held by the D flip-flop 26 until the horizontal synchronizing signal HS falls, as shown in FIG. 3e.

In this way, the output of the comparator 18 is “H”
level, and the Q output of the D flip-flop 26 is at the “H” level, the write pulse HCLK output from the write pulse generation circuit 20 is applied to the address counter 28.
is supplied to The count value counted by the address counter 28 is sequentially supplied to the address end AD of the buffer memory 10 via the multiplexer 29 as a write address. As a result, the video data VD of the scanning line S ₁₀₁ corresponding to the value "100" set in the data latch 16 by the CPU 1 changes from the 101st dot corresponding to the value "100" set in the data latch 23 to one dot. One address is assigned to each address and sequentially stored in the buffer memory 10.

Next, the video data VD from the 101st dot to the 612nd dot of the scanning line _S101 is stored in the buffer memory 10.
When stored in address latch 3, CPU1
Read addresses are sequentially set for 0. The read address set in the address latch 30 is transferred to the buffer memory 1 via the multiplexer 29.
The scanning lines stored in the buffer memory 10 are sequentially supplied to the address end AD of 0.
Video data VD from the 101st dot to the 612nd dot of _S101 is serially supplied dot by dot from the data output terminal DO to the thermal head drive circuit 11. Then, when the video data VD for 512 dots is supplied to the thermal head drive circuit 11, the CPU 1 supplies the print command PS to the thermal head drive circuit 11, and thereby,
The 512 heating elements of the thermal head 12 generate heat in a dot pattern corresponding to the video data VD.

As a result, from the 101st dot of the scanning line S ₁₀₁ on the display screen HG of the display device shown in FIG.
Pixel P in the first row corresponding to up to the 612th dot
(1, 1) to P(1, 512) are thermally transferred onto the paper 13 as shown in FIG. Next, print paper 1
3 is sent out one line in the direction of arrow F shown in the figure, and 1
The printing operation for the line ends.

When the printing operation for one line is completed, the CPU 1 sets the data latch 16 of the write scanning line specifying circuit 15 to the value "101" corresponding to the scanning line _S102 . Then, the output of the comparator 18 shown in FIG. 3h is obtained, and the output of the AND gate 19 shown in FIG. 3i is obtained. This results in
Video data VD from the 101st dot to the 612nd dot of the scanning line _S102 is stored in the buffer memory 10. Thereafter, in the same manner as described above, pixels P (2 _, 1 )～(2,512)
is thermally transferred onto the paper 13 as shown in FIG. 2B. Then, the printing paper 13 is sent out again by one line in the direction of arrow F shown in the figure.

Next, the CPU 1 sends the value "102" corresponding to the scanning line S ₁₀₃ to the data latch 16 of the write scanning line designation circuit 15.
Set to . Then, the output of the comparator 18 shown in FIG. 3j is obtained, and the output of the AND gate 19 shown in FIG. 3h is obtained. As a result, pixels P(3,1) to P in the third row corresponding to the 101st to 612nd dots of the scanning line _S103 on the display screen G of the display device shown in FIG.
(3, 512) is thermally transferred onto the paper 13 as shown in FIG.

By repeating such thermal transfer operation and changeover operation for one line alternately 256 times, that is, 256 scanning lines S ₁₀₁ to _{S 356} , one screen worth of pixels P (1,
1) ~ P (256, 512) are thermally transferred, thereby
Display screen HG of the display device shown in Figure 2 A
A hard copy of the image displayed in the print area PE is taken.

According to the embodiment described above, by using the digital switch 5, it is possible to easily designate any area of the high resolution display device having a display function of 1280×1024 dots as the print area PE.
Therefore, even with a small-width hard copy device having a thermal head 12 with 512 dot lines, it is possible to take a hard copy of the entire display screen by dividing the display screen of a high-resolution display device into multiple parts and making hard copies. You will be able to do this.

"Effects of the Invention" As explained above, according to the present invention, there is provided a printing head in which the number of printable dots per line is smaller than the number of display dots for one line of a display device; a buffer memory having a storage capacity corresponding to the number of printable dots; and a print area that is operable from outside the device and that designates any area on the display screen of the display device within a range determined by the number of printable dots as a print area. specifying means; generating a starting point of a horizontal dot range corresponding to the print area on the display screen of the display device as a writing start dot designation value, and a horizontal scan belonging to a line range corresponding to the print area; One line that is sequentially generated using the line number as a write operation line designation value, and that drives the printing head according to the data in the buffer memory each time writing of video data to be printed to the buffer memory is completed. a first control means for performing printing control for minutes and paper feeding control for feeding paper for one line; Counting the number of horizontal scanning lines, and when the count value matches the designated write scanning line value at that point in time, a dot corresponding to the designated write start dot value in the video data output from the display device is counted. The second control means selects video data corresponding to a predetermined number of dots starting from the position and writes the video data to the buffer memory as the video data to be printed. When making a hard copy of a high-resolution display device where the number of display dots per line is greater than the number of printable dots per line, a desired area on the display screen that can be printed is used. An area within a range corresponding to the number of dots can be arbitrarily designated as a printing area. Therefore, even if it is not possible to make a hard copy of the display screen of a display device at once due to the printing capacity of the printing head, it is possible to divide the display screen into multiple parts and make hard copies of the divided screens. By taking each image, it is possible to obtain a hard copy of the entire screen.
Furthermore, even when making hard copies of high-resolution display devices with a large number of display dots, the buffer memory that temporarily stores video data requires only the storage capacity equivalent to the number of printable dots of the printing head, making it economical. There is an advantage to having one.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention; FIGS. 2A and 2B are diagrams showing the relationship between the display screen HG of a high-resolution display device and a hard copy obtained by the embodiment; FIG. 3 is a timing chart for explaining the operation of the same embodiment.
FIGS. 4A and 4B are diagrams showing the relationship between a display screen G of a conventional display device and a hard copy obtained by a conventional hard copy device. HG...Display screen, PE...Print area, 1...
CPU, 2...ROM, 5...Digital switch (print area designation means), 10...Buffer memory, 11...Thermal head drive circuit, 12...
Thermal head, 15...Write scanning line designation circuit,
16...Data latch, 17...Counter, 18
... Comparator, 19 ... And gate, 20
...Write pulse generation circuit, 22...Write start dot designation circuit, 23...Data latch, 24...
... Counter, 25 ... Comparator, 28 ... Address counter, 29 ... Multiplexer, 30
...Address latch.

Claims (1)

[Scope of Claims] 1. A printing head in which the number of printable dots per line is smaller than the number of display dots for one line of a display device, and a buffer memory having a storage capacity corresponding to the number of printable dots; a print area designating means that is operable from outside the device and designates any area on the display screen of the display device within a range determined by the number of printable dots as a print area; and a display screen of the display device. Above, the start point of the horizontal dot range corresponding to the print area is generated as the write start dot specified value, and the number of the horizontal scanning line belonging to the line range corresponding to the print area is generated as the write scan line specification value. Each time writing of the video data to be printed to the buffer memory is completed, printing control for one line is performed to drive the print head according to the data in the buffer memory, and printing control for one line of paper is performed. a first control means for controlling the feeding of paper; and counting the number of horizontal scanning lines corresponding to video data currently being output from the display device based on a synchronization signal output from the display device; If the value matches the specified write scanning line value at the time, a predetermined number of dots starting from the dot position corresponding to the write start dot specified value in the video data output from the display device. A hard copy apparatus comprising: second control means for selecting video data corresponding to the range and writing it into the buffer memory as the video data to be printed.