JP2000094751A - Serial printer and method for operating serial printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a print quality by registering print positions of acceleration printing and high-speed skip printing. SOLUTION: In the case of acceleration printing, dots are printed with a delay by a delay time d1, d2, d3,... generated because of a characteristic of a motor to a phase switch time t1, t2, t3,... of a carriage motor during an acceleration period. Even after a constant-speed travel period starts, dots are printed at a time delayed by a delay time d4 when a last dot is printed in the acceleration period from each phase switch time t5, t6,.... In the case of high-speed skip printing, dots are printed only during the constant-speed travel period. In order to register a print position with that at the time of acceleration printing, dots are printed at a time delayed by a correction time (c) equal to the delay time d4 from each phase switch time t6, t7,....

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for accurately controlling a printing position of a serial printer.

[0002]

2. Description of the Related Art In a serial printer, a carriage (C
The print head mounted on the CR prints dots on the paper while running R). Therefore, it is necessary to control the printing timing of each dot according to the running condition of the CR so that each dot is printed at a correct position. One method of this print timing control is to detect the absolute position of the head with high precision using a rotary encoder coupled to the axis of the CR motor and feed it back to the control system to determine the print timing. There is a loop control. As a simpler control method, C
Step motor used for the R motor (for example, 2-2
Open-loop control without a feedback system that determines the print timing of each dot based on the phase switching timing of a phase type step motor) is also employed. Hereinafter, the latter open loop control will be described.

In this open loop control, the control system is C
The print timing is determined based on the phase switching timing of the drive signal given to the R motor. However, due to the mechanical and electrical factors of the CR motor, the actual phase switching of the motor is slightly delayed from the phase switching of the drive signal. However, such a delay can be ignored as long as printing is performed only during the constant speed traveling period. That is, during the constant speed traveling period, since the phase switching cycle of the drive signal and the actual phase switching cycle have the same length, it is assumed that the actual phase switching is performed simultaneously with the drive signal phase switching. Even if the print timing is determined ignoring the delay, dots can always be printed at a constant correct pitch, so that no particular problem occurs.

On the other hand, when performing so-called "accelerated printing", as shown in FIG. 1A, to perform printing even during the acceleration period before the CR enters the constant speed running as shown in FIG. Must be taken into account. That is, CR
During the acceleration period, the actual phase switching cycle becomes slightly longer than the phase switching cycle of the drive signal due to the influence of the delay. Therefore, during the acceleration period, it is necessary to predict the actual phase switching timing by adding the above-described delay time to the signal phase switching timing, and determine the printing timing based on the actual phase switching timing.

As a printing method for speeding up printing, there is a method called "high-speed skip printing" as shown in FIG. 1B in addition to the above-mentioned "accelerated printing". This means that the CR is moved at high speed from the position where CR stopped at the end of printing on the previous line to the printing start position on the next line,
Then, the printhead is decelerated before the print start position and enters a traveling at a constant speed, then reaches the printing start position, and performs printing only during the constant speed traveling period.

In order to effectively increase the printing speed, the above "high-speed skip printing" and "accelerated printing" are used together as follows. That is, when the distance from the position where the CR is stopped after the printing of the previous line is completed to the printing start position of the next line is relatively long, “high-speed skip printing” is performed.
If the distance is relatively short, "accelerated printing" is performed.

[0007]

In the high-speed skip printing, printing is performed only during the CR constant-speed running period. For the above-described reason, conventionally, the phase switching of the driving signal of the CR motor and the actual phase switching have been conventionally performed. , The printing timing is determined ignoring the delay. On the other hand, in the accelerated printing, for the reason described above, the printing timing is intentionally delayed from the phase switching timing of the drive signal in consideration of the delay time during the acceleration period.

In the accelerated printing, the delay of the printing timing with respect to the phase switching timing intentionally added during the acceleration period is maintained even after the shift to the constant speed running period because the dot pitch must be kept constant. There is a need. However, as described above, in high-speed skip printing, such intentional delay is not added to the print timing. As a result, when both high-speed skip printing and accelerated printing are used, the printing position of dots is slightly shifted between the line printed by high-speed skip printing and the line printed by accelerated printing.

This will be described with reference to the time chart of FIG. FIG. 2A shows the phase switching times t0, t1, t2,... Of the drive signal in the acceleration period of the CR motor and the subsequent constant speed period. FIG. 2 (B),
In (C), the printing time of each dot in accelerated printing and high-speed skip printing is indicated by a dot (in fact, the position where the dot is to be printed and the phase switching position of the motor completely match. Therefore, the printing timing is intentionally corrected in accordance with the distance between the two positions. However, in FIG. 2, for simplification of description, when the correction amount is zero, That is, the printing timing is illustrated by taking an example of printing each dot at each phase switching position of the motor).

In accelerated printing, as shown in FIG. 2B, during the acceleration period, each phase switching time t1, t2, t3,.
This is performed at a time delayed by predetermined delay times d1, d2, d3,... (That is, a predicted actual phase switching time).
Then, the delay time of the last dot of the acceleration period (d in FIG. 2)
4) is maintained as it is even at the printing timing of each dot in the subsequent constant speed period. On the other hand, in the high-speed skip printing, as shown in FIG. 2C, each dot is printed in synchronization with each phase switching time t6, t7,. As a result, a shift occurs between the dot position for accelerated printing and the dot position for high-speed skip printing by the delay time d4 added during the constant speed running period during accelerated printing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the print quality by matching the print positions of accelerated print and high-speed skip print.

[0012]

According to the serial printer of the present invention, the delay time of the printing timing with respect to the phase switching timing of the driving signal during the constant speed running period of the acceleration printing is stored as a correction value, and the high speed skip printing is performed. Is performed, the print timing of the first dot is determined by taking the correction value into consideration with the phase switching timing of the drive signal. Then, the first dot is printed at this printing timing, and thereafter, the second and subsequent dots are printed at a predetermined dot pitch from the first dot. As a result, the printing positions of the accelerated printing and the high-speed skip printing coincide.

[0013]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2D shows the print timing of high-speed skip printing according to an embodiment of the present invention. In the present embodiment, the printing timing of the accelerated printing is the same as that of the conventional one shown in FIG. 2B (as described above, in FIG. The correction factor of the print timing based on factors other than the delay of the phase switching timing is zero, but those skilled in the art
It should be clearly and easily understood from the following description that the present invention can be similarly applied when those correction elements are added).

As shown in FIG. 2B, in accelerated printing,
During the CR acceleration period, printing is started at the phase switching time t0 one cycle before the phase switching cycle reaching the printing start position (start of the process of measuring the printing time), and thereafter, each phase switching time t
The head is driven to print dots at each time (predicted actual phase switching time) obtained by adding predetermined delay times d1, d2,... To 1, t2,. When the acceleration period ends and the constant speed running period starts, the same delay time as the last printing delay time of the acceleration period, for example, d4 is maintained, and each phase switching time t5, t6,. A dot is printed at each later time.

On the other hand, in the high-speed skip printing, the high-speed skip is completed, the constant-speed running period is started, and the phase switching time one cycle before the phase switching cycle to reach the printing start position, for example, t5,
, And thereafter, the head is driven to print dots at a time later than each phase switching time t6, t7,... By a preset correction time c. The correction time c is the delay time d4 during the constant-speed running period in the acceleration printing.
Is set to a value equal to Therefore, the printing positions of the accelerated printing and the high-speed skip printing exactly match.

FIG. 3 shows a configuration for driving the head according to the present embodiment.

The control circuit 1 includes, for example, a microcomputer in a printer and peripheral circuits associated therewith, and executes a print timing generation process 1, a CR motor control process 5, and the like. The print timing generation process 1 determines the print time of each dot as described later, and drives the print head 9 at each print time via the head drive circuit 7 to print the dots. The CR motor drive circuit 3 is connected via the motor drive circuit 11 to C
The R motor 13 is driven to drive the CR.

FIG. 4 shows the overall processing flow of the control circuit 1 when printing one line by high-speed skip printing.
FIG. 5 shows the change of the CR speed at that time and the printing time of each dot along the time axis.

As shown in FIG. 4, when a print command for the line is issued (S1), parameters necessary for printing are prepared (S2). The parameters include, for example, a correction time c for aligning with the above-described accelerated printing, and a correction value for various factors that have been taken into account in the past (in FIG. Uni-D correction value for compensating for the shift between the phase switching position of the dot and the position where the dot is to be printed, the delay from when the drive signal is supplied to the head until the dot is actually printed, and bidirectional printing. Bi-D correction value for compensating for the difference between the print timings of the forward pass and the return pass at the time. And CR
The motor is started (S3). Thereafter, the CR moves in a speed pattern with a high-speed skip as shown in FIG. After the CR finishes the high-speed skip and enters the constant speed running,
Printing is started at a phase switching time t0 which is one cycle before the phase switching cycle at which the printing position of the first dot 101 is reached, and the next phase switching time t1 is set using the above-described parameters.
, Print timing data indicating the time α from the time until the printing time of the first dot 101 is calculated and set in the timer (S
4). The timer starts counting at the next phase switching time t1.
When the timer counts the set time α, the print interrupt process is started to cause the head to print the first dot 101 and to set the print timing data indicating the print time of the second dot 102 in the timer (S5). Thereafter, the printing of the second and subsequent dots 102, 103,... Is repeated at a constant time interval corresponding to the dot pitch at the time of constant speed traveling (S6).

FIG. 6 shows, in more detail, the processing performed by the print timing generation process 3 shown in FIG. 3 in the overall processing shown in FIG.

Here, it is assumed that the CR coordinates are expressed in units of 1/120 inch (which is the pitch of the phase switching position), while the printing positions are expressed in units of 1/1440 inch. And

As shown in FIG. 6, when a print command is received,
The print timing generation process 3 calculates printing parameters (correction time c for alignment with accelerated printing, Uni-D correction value, Bi-D correction value, etc., as described above) according to the printing speed. (S11) Next, the print start position, that is, the print position of the first dot (in units of 1/1440 inches) is divided by the value of 1/120 inches, which is the unit of the CR motor coordinates, and
Ask for the quotient and the remainder. The quotient indicates the phase switching time t1 at which the print interrupt activation shown in FIG. 5 is performed. Then, the phase switching time t0 at which the printing start shown in FIG. 5 should be started is obtained from the quotient, and the printing start is started at the time when the phase switching time t0 comes (S13).

On the other hand, the remainder at step S12 is as shown in FIG.
Is a value indicating a deviation between the phase switching position corresponding to the phase switching time t1 shown in FIG. About this remainder, after dividing this by the constant speed traveling speed of CR and converting it into time data,
Print timing data indicating the print time of the first dot 101 shown in FIG. 5 by adding the Uni-D correction value, the Bi-D correction value, and the correction time c for alignment with the accelerated printing described above. α is calculated (S14).

When printing is started in step S13, the print timing data α of the first dot obtained in step S14 is set in the print interrupt timer (S1).
5). The interrupt timer starts counting at the next phase switching time t1 after the printing is started, and when the timer counts the printing timing data α, a printing interrupt process is performed (S16). In this print interruption process, the head is driven to print the first dot 101,
The print timing data at the time of constant speed running indicating the print timing of the second dot 102 is set in the print interrupt timer, and the constant speed printing process is started. This constant speed printing process
The dots are printed at a constant period according to the CR constant speed traveling speed, and are basically the same as the conventional constant speed printing process. After the first dot 101 is printed, the first dot 10 is printed by the same constant-speed running printing as in the past.
The second and subsequent dots 102, 10 at a constant pitch from 1
3, 104,... Are printed.

As described above, in the high-speed skip printing, when determining the printing timing of the accelerated printing, the delay time maintained during the constant-speed running period in the accelerated printing is taken into consideration, so that the printing of the accelerated printing and the high-speed skip printing is performed. The positions will match.

The embodiments described above are merely for explanation of the present invention, and the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the invention. Deformation is possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of accelerated printing and high-speed skip printing.

FIG. 2 shows the timing of phase switching of a drive signal of a CR motor,
6 is a time chart showing the relationship between print timings in accelerated printing, conventional high-speed skip printing, and high-speed skip printing according to an embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 4 is an exemplary flowchart showing the overall processing flow of high-speed skip printing control in the embodiment.

FIG. 5 is an explanatory diagram of the operation of high-speed skip printing in the embodiment.

FIG. 6 is a flowchart showing the processing of a print timing generation process in high-speed skip printing of the embodiment.

[Explanation of symbols]

Reference Signs List 1 control circuit 3 print timing generation process 5 CR motor control process 9 print head 13 CR motor 101, 102, 103, 104 dots t0, t1, t2,... CR motor drive signal phase switching time d1, d2, d3,. Delay time during printing c Correction time for alignment between high-speed skip printing and accelerated printing α Print timing data for the first dot in high-speed skip printing

Claims (4)

[Claims] 1. A serial printer which uses a method of determining a print timing based on a phase switching timing of a drive signal of a carriage motor and uses both accelerated printing and high-speed skipping printing, wherein the serial printing during the constant speed running period in the accelerated printing is performed. A correction time unit having a predetermined correction value corresponding to a delay time of a print timing with respect to a phase switching timing; and when performing the high-speed skip printing, a correction value from the correction time unit is added to the phase switching timing, First print control means for determining the print timing of the dot, and when performing the high-speed skip printing, the second and subsequent dots so that the second and subsequent dots are printed at a predetermined dot pitch from the first dot. Constant-speed printing control means for determining the printing timing of each dot; Printing,
A serial printer comprising a print head and a head drive circuit. 2. The printer according to claim 1, wherein the first print control means includes a second correction value, a Uni-D correction value, and a Bi-D correction value for compensating for a deviation between the phase switching position of the carriage motor and the printing position, in addition to the correction value. 2. The serial printer according to claim 1, wherein the print timing of the first dot is determined by further considering at least one of the correction values. 3. A method of operating a serial printer using a method of determining printing timing based on a phase switching timing of a drive signal of a carriage motor and using both accelerated printing and high-speed skipping printing, wherein: Acquiring a predetermined correction value corresponding to a delay time of the printing timing with respect to the phase switching timing in the middle; and performing the high-speed skip printing. (1) First, taking the correction value into consideration with the phase switching timing (2) printing the first dot at the printing timing of the first dot; and (3) second and subsequent dots at a predetermined dot pitch from the first dot. And a method of operating a serial printer. 4. A step of determining the print timing of the first dot, wherein in addition to the correction value, a second correction value for compensating for a deviation between a phase switching position of the carriage motor and the print position, a Uni-D correction The method according to claim 3, further comprising at least one of a value and a Bi-D correction value.