JPH0647290B2 - Printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention calculates a dot duty in one print line for each duty detection area over a predetermined number of dot rows in one print line, The present invention relates to a printing device that prints a print line by a plurality of printing operations when a duty detection area having a dot duty of a predetermined value or more exists in the print line.

(b) Conventional technology It is ideal to set the drive power supply capacity of the print head based on the conditions for full dot printing by driving all the printing elements arranged in a dot row, but in reality, normal printing The amount of power consumed during operation is about 1/2 of the above capacity.
Since it is only the following, a drive power source having a capacity corresponding to the amount of power consumed during a printing operation of a normal character or the like is used to reduce the cost of the printing apparatus.

However, when a figure or the like is printed using the drive power supply of the above capacity, the drive rate of the printing element, that is, the dot duty is higher than in the printing operation of normal characters, and a lot of power is consumed. The printing element could not be reliably driven by the above driving power source. As a result, there is a problem that the printing quality is deteriorated due to so-called dot omission.

Therefore, in the print control method disclosed in Japanese Patent Laid-Open No. 59-16765, the dot duty is detected based on the total number of dots and the number of print dots in one print line, and the dot duty is set as the capacity of the driving power supply. If the dot duty is less than or equal to the predetermined value, the print element to be driven is divided into a plurality of divided print elements to be driven. The above problems have been solved by controlling printing so that characters and figures are printed.

(c) Problems to be Solved by the Invention However, in the print control method described above, the print control is performed based on the average value of the number of print dots with respect to the total number of dots in one print line. When graphic data with a high dot duty, space data with a low dot duty, and character data are mixed in the print line, the dot duty as a whole will be low despite the high dot duty when printing the graphic data. Therefore, printing was performed by one printing operation.

For this reason, when printing continuous graphic data, the driving voltage is lowered and the printing element cannot be reliably driven for printing, resulting in poor graphic printing quality due to missing dots or the like.

(d) Means for Solving the Problems In view of the above-mentioned conventional drawbacks, the object of the present invention is to determine the dot duty of one print line for each duty detection region over a predetermined number of dot columns in the one print line. It is an object of the present invention to provide a printing device capable of printing characters, figures and the like with high quality by using a small-capacity drive power source by calculating.

Therefore, the present invention is directed to a printing apparatus configured to print a character, a figure, or the like by selectively driving a plurality of printing elements that form a dot row of the print head according to the movement of the print head. To calculate the dot duty in the duty detection area based on the total number of dots in the duty detection area and the number of print dots actually printed over a predetermined number of dot rows smaller than the total number of dot rows in the print line The duty calculating means, the area moving means for sequentially moving the duty detection area by the number of dot rows smaller than the number of dot rows in the duty detection area over the entire one print line, and the area moving means. Whether or not the dot duty sequentially calculated by the duty calculating means along with the movement of the duty detection area is equal to or more than a predetermined value. Judgment means for making a judgment, and when there is a duty detection area in which the dot duty is judged to be a predetermined value or more by the judgment means in the one print line, the print line is divided into a plurality of times and printed. And a print control unit for controlling the above.

(e) Action of the Invention According to the present invention, the duty calculation means calculates the dot duty of one print line for each duty detection area over a predetermined number of dot rows in the one print line, and If there is a duty detection area for which the determination means determines that the dot duty is greater than or equal to a predetermined value, the print line is divided into a plurality of times for printing. At this time, the area moving means moves the duty detection area for each dot row that is smaller than the number of dot rows in the duty detection area, so that the ends of the duty detection areas overlap. In this way, since the duty detection area is moved over the entire print line with its end portion overlapping and the dot duty is sequentially detected for each duty detection area to perform print control, graphic data with a high dot duty is displayed. It is possible to print with high print quality by using a small-capacity drive power supply even when the image is locally continuous.

(f) Effects of the Invention As described above, the present invention uses a small-capacity drive power source to detect characters, figures, and the like with high quality by sequentially detecting dot duty for each duty detection area over the entire print line. Can be printed. In addition, it is possible to suppress the decrease in the printing speed due to it. Further, since the duty detection areas are overlapped, there is an effect that it is possible to surely cope with the dot concentration at any position.

(g) Example Hereinafter, the present invention will be described according to an example in which a dot impact type printing apparatus is implemented.

In FIG. 1 and FIG. 2 which show the duty calculating means, the area moving means, the judging means, and the print controlling means of the present invention and the dot duty detection state, a central processing unit (hereinafter, referred to as CPU) 10 includes a ROM 12 and a RAM 14.
Are connected to each other, and the ROM 12 has a total dot number memory area 15, a pattern memory area 16, and a program memory area 18. The pattern memory area 16 stores various pattern data corresponding to print data such as characters and figures, and the program memory area 18 previously stores program data for executing a printing operation and a dot duty detecting operation. ing. RAM 14
Is the number of print dots memory area 19, input buffer area 20
And a print buffer area 22. The input buffer area 20 stores print data for one print line transferred from an external device such as a host computer (not shown) via the interface 24. The printer buffer area 22 also stores dot pattern data for one print line accessed from the pattern memory area 16 based on the print data. The CPU 10 sets a duty detection area from the first dot row to a predetermined number of dot rows on the dot pattern data of one print row stored in the print buffer area 22 on the basis of a print command from an external device. The number of print dots actually printed in the duty detection area is stored in the print dot number memory area 19 of the RAM 14. The range of the duty detection area (the number of dot rows) is set in advance in relation to the capacity of the driving power supply, and is a range in which no dot omission occurs in the printing operation when all the printing wires of one dot row are driven. That is, when each dot row is sequentially applied in a state in which all the printing wires are driven, dot dropouts and the like begin to occur due to the voltage drop of the driving power supply gradually with the printing operation. Therefore, such a dot dropout does not occur, and the number of printable dot rows is set.

Further, the CPU 10 calculates the dot duty in the duty detection area based on the total number of dots stored in the total dot number memory area 15 of the ROM 12 and the number of print dots stored in the print dot number memory area 19 of the RAM 14. To do. Then, the calculated dot duty is RO
The dot duty value stored in the dot duty memory area 17 of M12 is compared to determine whether or not the dot duty value is equal to or more than the dot duty value.

Further, the CPU 10 prints the number of print dots stored in the number-of-print-dots memory area 19 of the RAM 14, and print dots of a dot row located forward of the duty detection area in the moving direction, that is, on the final dot row side (right side in FIG. 2). Add the number, subtract the number of dots printed in the dot row located behind the movement direction in the duty detection area, that is, on the head dot row side (left side in FIG. 2), and move the duty detection area toward the final dot row side. Move one dot row (in FIG. 2, move one dot row to the right). Then, the dot duty of the newly set duty detection area is calculated again. The movement of the duty detection area is not limited to one dot row at a time, and may be moved two dot rows at a time.

Then, when there is a dot duty detection area in which the dot duty exceeds the dot duty stored in the dot duty memory area 17 of the ROM 12, the CPU 10 prints the one print line in plural times. Print control. This printing may be performed twice by an arbitrary method such as dividing into even-numbered pins and odd-numbered pins. The printing of one print line is not limited to twice, but may be printed twice or more.

A print head drive circuit 34 is connected to the CPU 10, and a print head 35 is connected to the print head drive circuit 34. The print head 35 has a dot row in which a predetermined number of print wires are arranged in a direction orthogonal to the print row, and the print wires are selectively selected based on the dot pattern data stored in the print buffer area 22. Printing is driven by a driven electromagnet device (neither is shown). Further, the print head 35 is connected to a drive power source having a capacity that does not hinder the printing operation of ordinary characters and the like.
A carriage drive circuit 36 is connected to the CPU 10, and the carriage drive circuit 36 rotationally drives a carriage drive motor 38 based on an inputted carriage drive signal to reciprocate a carriage having a print head along a print line. Let A paper feed drive circuit 40 is connected to the CPU 10, and the paper feed drive circuit 40 rotates the paper feed drive motor 42 by a predetermined angle based on the input paper feed signal so that the next print line of the print paper is printed. Feed the printing paper so that it is positioned at the printing position.

Next, the operation will be described with reference to FIG.

The CPU 10 inputs the input buffer area 2 in step 50.
The data stored in 0 is taken in, and it is determined in step 52 whether the data taken in is print command data. If the result of the determination in step 52 is NO, and the fetched data is print data, the CPU 10 determines in step 54 based on this print data the pattern memory area 1
After accessing the corresponding dot pattern data from 6, the dot pattern data accessed in step 56 is transferred to the print buffer area 22. By repeating this operation, the pattern data corresponding to the print data for one print line stored in the input buffer area 20 is stored in the print buffer area 22.

If the fetched data is the print command data and the determination in step 52 is YES, the CPU 10 determines in step 58 from the leading dot row on the dot pattern data stored in advance in the print buffer area 22 in step 56. As shown in FIG. 2, the duty detection area is set over a predetermined number n of dot rows that is smaller than the total dot row number L of one print line and is 1 or more. Then, in step 60, the number of print dots in the duty detection area is counted and stored in the print dot number memory area 19 of the RAM 14. Next, the CPU 10 proceeds to step 62.
In the RAM 14, the dot duty in the duty detection area is calculated based on the print dot number stored in the print dot number memory area 19 of the RAM 14 and the total dot number stored in the total dot number memory area 15 of the ROM 12, and the result is R
The dot duty value stored in the dot duty memory area 17 of the OM 12 is compared (step 64). Then, if the determination in step 64 is YES, it is determined in step 66 whether or not the detection of the dot duty over the entire print line is completed. In this case, the dot duty in the vicinity of the leading dot row is only detected in one print row, so the determination in step 66 is NO. Therefore, in step 68, the CPU 10 adds the number of print dots of the dot row located on the final dot row side of the duty detection area to the number of print dots stored in the print dot number memory area 19 of the RAM 14. Then, at step 70, the number of print dots of the dot row located on the side of the topmost dot row of the duty detection area is subtracted from the number of print dots stored in the print dot number memory area 19, and the duty detection area corresponds to one dot row. Just move to the final dot row side. By this processing, the duty detection area of the area width n columns is moved by the number 1 smaller than n.
Then, in step 64, the dot duty of the newly set duty detection area is calculated again. By repeating steps 62 to 70 in this manner, the dot duty of the dot pattern data of one print line stored in the print buffer area 22 of the RAM 14 is detected. In the dot duty detection process, when the dot duty of a certain duty detection area exceeds the dot duty value stored in the dot duty memory area 17 of the ROM 12, the CPU 10
Determines NO in step 64. As a result, C
In step 72, the PU 10 prints characters, figures, etc. in two steps based on the dot pattern data stored in the print buffer area 22. If the dot duty of the duty detection area does not exceed the dot duty value stored in the print dot number memory area 19, the determination of step 66 becomes YES when the detection of the dot duty of one print line is completed. , CPU1
In step 0, characters, figures, etc. are printed by one printing operation based on the dot pattern data stored in the print buffer area 22 in step 74.

As described above, in the present embodiment, the dot duty over one entire print line is detected for each duty detection area including a predetermined number of dot rows set according to the capacity of the drive head power supply. Is a predetermined value or more according to the capacity of the driving power source, the printing wire driven for printing is divided into a plurality of pieces, and the characters, graphics, etc. for one printing line are printed by a plurality of printing operations. As a result, it is possible to print a graphic particularly with high quality by using a low-cost and low-cost drive power source that is consumed during a normal printing operation.

Although the present embodiment has been described as an impact type printing apparatus, the present invention can be naturally applied to a thermal type printing apparatus using a thermal paper or a thermal transfer type printing apparatus using a thermal transfer ribbon.

[Brief description of drawings]

FIG. 1 is an electrical block diagram of the printer of the present invention, FIG. 2 is an explanatory diagram showing a dot duty detection state, and FIG. 3 is a flow chart showing the operation of the printer. In the figure, 10 is a CPU as a control device, and 35 is a print head.

Claims (3)

[Claims] Claim: What is claimed is: 1. A printing apparatus, wherein a plurality of printing elements forming a dot row of a print head are selectively driven according to the movement of the print head to print characters, figures, etc. For calculating the dot duty in the duty detection area based on the total number of dots in the duty detection area and the number of print dots actually printed over a predetermined number of dot rows smaller than the total number of dot rows in a row A duty calculating means; an area moving means for sequentially moving the duty detection area by the number of dot rows smaller than the number of dot rows in the duty detection area over the entire one print line; and a duty by the area moving means. It is determined whether the dot duty sequentially calculated by the duty calculation means according to the movement of the detection area is a predetermined value or more. And a determination unit for performing the printing, when a duty detection area in which the determination unit determines that the dot duty is equal to or more than a predetermined value exists in the one print line, the print line is printed in a plurality of times. A printing apparatus, comprising: 2. The printer according to claim 1, wherein the area moving means moves the duty detection area by one dot row at a time. 3. The area moving means adds means for adding the number of print dots of a dot row located in front of the duty detection area in the moving direction, and print dot of a dot row located in the rear part of the duty detection area in the moving direction. The printing device according to claim 1 or 2, further comprising: a subtracting unit that subtracts the number.