JPH0224226B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a serial printer that performs bidirectional logic seek printing using a step motor, and particularly to a dot printer that performs printing using an open loop control method using a microcomputer and has a staggered dot arrangement. It is about the method.

In a dot printer with a staggered dot arrangement, as shown in Figure 1, the spacing between even and odd dots is n (an integer) times the pitch of the step motor, or An integer multiple of an integer fraction is used. Therefore, the horizontal dot width of the character is an integral multiple of the motor pitch, or an integral multiple of the least common multiple of the motor pitch and the staggered dot spacing.

FIG. 2 is a diagram showing the printing timing and the position of characters actually printed in a conventional printing method. A system that uses a basic clock as a trigger, as shown in FIG. 2, is used. In printers that perform bidirectional printing, the actual print position deviates from the theoretical print position due to the back crash of the drive system that moves the head left and right and the time required to create the print timing. A system has been adopted in which a number of correction steps are inserted each time printing is started. τ ₁ is the period of the basic clock for controlling the print timing and the drive timing of the step motor, and τ ₂ is the time that defines the print dot pitch, which is an integral multiple of the basic clock. τ ₃ and τ ₄ are compensation times for aligning the vertical printing positions of characters in a column in the case of bidirectional printing, and have a time width that is an integral multiple of the period τ ₁ of the basic clock. τ ₃ is the compensation time when printing in the forward direction, and τ ₄ is the compensation time when printing in the reverse direction.

Figure 3 shows the conventional dot printer
This is a general flowchart for the CPU to generate a forward print clock. Each time the basic clock in Figure 2 occurs, the basic clock is counted as shown in Process 1 in Figure 3, and in Process 2 the compensation time τ is used to align the vertical printing positions of the two rows of characters. After determining that a number equivalent to ₃ has been counted, in process 3 it is determined that the timing clock is an odd-numbered dot printing timing clock made by an integral multiple of the basic clock, and in process 4, an odd-numbered dot printing clock is output. In process 5, after printing of odd-numbered dots has started, it is determined that the basic clock has been counted for a time corresponding to the staggered dot interval, and the process moves to process 6. In process 6, it is determined that the even number dot printing timing clock has a cycle that is an integral multiple of the basic clock, similar to the odd number dot printing clock, and
In process 7, an even number dot printing clock is output.

On the other hand, in the case of reverse printing, in a printer with the dot arrangement shown in Figure 1, even numbered dots must be printed first, so as shown in processes 8 to 14 in Figure 4, even numbered dots are The printing timing of dots and odd-numbered dots is reversed from that in FIG.

As shown in Figure 2, conventional dot printers print based on the basic clock, so when printing one line, for example, characters with different numbers of printed dots are mixed in that line. In this case, printing is possible if the printing dot pitch is an integral multiple of the basic clock as shown in Figure 2, but if the period of the printing dot clock is not an integral multiple of that of the basic clock as in the characters in Figure 5. Printing dot pitch: τ ₂ = m ₁ τ ₁ , m ₁ = τ ₂ / τ ₁ (m ₁ is not an integer) Printing correction time: τ ₃ = 2τ ₁ staggered dot interval: n = 3τ Difference in ₁ printing dot pitch The delay time for printing a character: τ ₄ = m ₂ τ ₁ (m ₂ is not an integer), but since the timing of τ ₂ and τ ₄ cannot be set, printing cannot be performed.

Furthermore, in conventional technology, the vertical position of two lines of printing in bidirectional printing is often corrected based on a basic clock that is synchronized with the step of the motor. Can not. That is, the dot shift d in the two vertical columns in FIG. 2 is at maximum τ ₁ . Therefore, if the period of the basic clock is shortened, accuracy can be further improved, but this increases the number of processing steps shown in the general flowcharts in Figures 3 and 4, which increases the processing time and increases the printing speed. Limited by speed. As a basic clock, the third
This is because a period shorter than the minimum cycle that can process the general flow shown in FIGS. 4 and 4 cannot be used.

The purpose of the present invention is to enable use of any pitch between staggered dots, to enable printing even when characters with different printing dot pitches coexist in one line, and to enable printing even in the case of bidirectional printing. To provide a printing method for a dot printer which enables accurate correction of printing position and enables high-speed printing compared to the conventional method which requires a microcomputer operated by a machine clock.

The printing method of the dot printer of the present invention performs bidirectional logic seek printing and generates a character trigger for each character printed by the dot printer whose print head is arranged in a staggered dot arrangement. A first trigger delayed by a first compensation time for position compensation is generated, and the first trigger is delayed by a time equal to the time obtained by dividing the interval between staggered dots by the moving speed of the print head plus the first compensation time. generating a second trigger delayed with respect to the character trigger; the first and second triggers causing an even number dot printing clock;
The present invention is characterized in that an odd-numbered dot printing clock is independently generated and printing is performed by the printing head.

An embodiment of the present invention is shown in a block diagram in FIG. 6, and FIGS. 7 and 8 show its operation timing. A high-speed clock generator 21 generates a high-speed clock. Based on this, the CPU 22 edits and generates a basic clock according to the printing speed. The character trigger generator 23 converts the basic clock to the number of clocks for one character. Divide the frequency by and generate a character trigger. The print correction time generating section 24 generates a trigger that is delayed by the correction time _T1 for bidirectional printing with respect to the character trigger, and the print correction time generating section 25 generates a staggered dot interval at the print head at the correction time _T1 . The trigger is generated with a delay of a compensation time T ₁ + t ₁ = T ₂ , which is calculated by adding the time t ₁ divided by the moving speed of the carriage.

When the dot arrangement is as shown in FIG. 1, when performing forward printing, a print direction command from the CPU 22 is used, and a trigger generated by the generator 24 as shown in FIG. An odd number dot printing clock is generated from the odd number dot printing clock generation section 26, and an even number dot printing clock is generated from the even number dot printing clock generation section 27 using the trigger generated by the generation section 25 at a cycle corresponding to the pitch of the characters. Prints like characters.

Also, when printing in the reverse direction, similarly
In response to a print direction command from the CPU 22, as shown in FIG.
From this, an odd-numbered dot printing clock is generated at a period corresponding to the pitch of the characters, and printing is performed as characters, characters, characters.

In this way, serial printers that perform bidirectional logic printing, especially dot printers that print using an open-loop control method using a step motor and have a staggered dot arrangement, use mechanical back-crashes and printing in the direction of movement of the head. Compensation time to account for time delays in control
Set T ₁ and inter-dot pitch compensation time T ₂ , and in the case of forward printing, print characters, characters, characters at the timing as shown in Figure 7, and in the case of reverse direction printing, print the characters at the timing shown in Figure 8. Characters are printed at the timing shown in the figure, and the vertical printing positions of the characters in FIG. 7 and the characters in FIG. 8 are made to match.

Furthermore, by outputting the odd-number dot printing clock and the even-number dot printing clock independently and asynchronously with the basic clock, the even-number and odd-number dot printing processes in the prior art shown in FIGS. 3 and 4 can be separated. Figure 7, Figure 8 characters, characters,
It is possible to print characters with different printing pitches, such as characters, and to increase the printing speed by dividing processing.

According to the present invention, there is provided a dot printer that can easily and reliably adjust the printing position when performing bidirectional logic seek printing, can print characters with all kinds of printing dot pitches mixed in the line, and can print at high speed. realizable.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the well-known staggered dot arrangement of printed dots, Fig. 2 is an explanatory diagram showing the operation of the conventional example, Figs. 3 and 4 are flowcharts showing the operation of the CPU in the conventional example; 5 is a timing diagram showing the drawbacks of the conventional example, FIG. 6 is a block diagram showing an embodiment of the present invention, and FIGS. 7 and 8 are explanatory diagrams showing the operation of FIG. 6. 21...High-speed clock generator, 22...CPU,
23... Character trigger generation section, 24... Print compensation time generation section, 25... Print compensation time generation section, 26
...Odd number dot printing clock generation section, 27...Even number dot printing clock generation section, 28...Odd number dot data output section, 29...Even number dot data output section, 30...Print head section, 31...Step motor driver Department.

Claims (1)

[Claims] 1 A character trigger is generated for each character printed by a dot printer that performs bidirectional logic seek printing and the print head is arranged in a staggered dot arrangement. generates a first trigger delayed by a compensation time of , and generates a first trigger delayed with respect to the character trigger by a time equal to the staggered dot interval divided by the print head movement speed plus the first compensation time. A printing method for a dot printer, characterized in that two triggers are generated, and the first and second triggers independently generate an even-numbered dot printing clock and an odd-numbered dot printing clock to cause the printing head to print.