JP3615178B2 - Printer control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer control device, and more particularly to a print timing control device for an inkjet printer.
[0002]
[Prior art]
First, printing control of a general inkjet printer will be described with reference to FIG. In this inkjet printer, the carriage 2 on which the print head 1 is mounted reciprocates across the recording medium 6, and printing is performed by ejecting ink droplets from the print head 1 at that time. Usually, a motor 3 is used to reciprocate the carriage 2. The reciprocating motion of the carriage 2 is realized by converting the rotational motion of the motor 3 into the linear motion of the carriage 2 by a mechanism not shown and switching the rotational direction of the motor 3.
[0003]
Here, a linear encoder 7 including a linear scale 4 and an optical sensor 5 is used for position control and movement speed control of the carriage 2. The linear scale 4 is installed in parallel with the reciprocating direction of the carriage 2. The optical sensor 5 detects the pattern printed on the linear scale 4, converts it into an electrical signal, outputs it, and controls the motor 3 based on this to perform the above-described position control and movement speed control of the carriage 2. .
[0004]
An important function of the linear encoder 7 is the generation of printing timing (timing for ejecting ink droplets). In general, the resolution of the encoder output used for generating the printing timing of the ink jet printer is lower than the density of dots to be printed. For example, the encoder output is 300 dpi and the print density is 1200 dpi, or the encoder output is 200 dpi and the print density is 600 dpi. As described above, since the print density is higher than the resolution of the encoder output, a method of multiplying the encoder output by some method is required to generate the print timing from the encoder output.
[0005]
An example of this type of prior art is described in Japanese Patent Laid-Open No. 2000-135829. FIG. 19 is a timing chart thereof, and FIG. 20 is a detailed diagram of a print timing generation circuit in the printer control apparatus. This printer control device has proposed a print timing generation circuit capable of printing even when the number of divisions increases when dividing the encoder output period to generate the print timing in order to multiply the encoder output.
[0006]
19, the reference position pulse Load1 output in synchronization with the rise of the A phase output of the encoder is defined as BP1, BP2, BP3, BP4. Assume that the intervals between the pulses of BP1, BP2, BP3, BP4... Are different as T1, T2, T3, T4. For the reference position pulses Load1BP1, BP2, BP3, BP4,..., The interval between these pulses is divided into four to create a print timing pulse. The print timing pulse starts from the reference position pulse Load1BP2. For example, a value obtained by summing the intervals between the pulses of the printing timing pulse starting from the reference position pulse BP2 by four pulses is equal to the interval T1 between pulses from the reference position pulse BP1 to the reference position pulse BP2.
[0007]
The print timing generation circuit shown in FIG. 20 includes two up counters 51 and 52, two latch circuits 53 and 54, four comparators 55, 56, 57, and 58, and one 3/4. It comprises a divider 59, four 2-input AND gates 60, 61, 62, 63, and one 4-input OR gate 64.
[0008]
The reference position pulse Load 1 is supplied to the Load terminal of the up counter 51 and the Enable terminal of the latch circuit 53. Further, the system clock CLK is supplied to the up counters 51 and 52 and the clock terminals of the latch circuits 53 and 54. Further, a reset bar signal that rises at the printing start point is supplied to the up counter 52, the latch circuits 53 and 54, and the AND gates 60 to 63, respectively.
[0009]
The up counter 51 constitutes a time measuring means, and inputs a reference position pulse Load1 to measure the elapsed time between adjacent reference positions with the system clock CLK from the reference position. The elapsed time measured by the up counter 51 is latched by the latch circuit 53, and this is repeated. Accordingly, the latch circuit 53 outputs the elapsed time between the reference positions, and updates the time every time the reference position pulse Load1 is input.
[0010]
The up counter 52 starts counting with the system clock CLK from the rise of the Reset bar signal, supplies Q0 to Q5 of the outputs Q0 to Q7 to the comparator 55, and compares Q0 to Q6 of the outputs Q0 to Q7. Q0 to Q7 are supplied to the comparators 57 and 58.
[0011]
The comparator 55 compares the outputs Q0 to Q5 of the up counter 52 with the outputs Q2 to Q7 of the latch circuit 53. That is, a value of 1/4 (1/4) of the measured reference position interval T1 is compared with the value of the up counter 52, and the print timing pulse TP2 is output.
[0012]
The comparator 56 compares the outputs Q0 to Q6 of the up counter 52 with the outputs Q1 to Q7 of the latch circuit 53. That is, 2/4 of the measured reference position interval T1 is compared with the value of the up counter 52, and the print timing pulse TP3 is output.
[0013]
The comparator 57 compares the values obtained by dividing the outputs Q0 to Q7 of the up-counter 52 and the outputs Q0 to Q7 of the latch circuit 54 by 3/4 by the 3/4 divider 59. That is, the measured value of 3/4 of the reference position interval T1 is compared with the value of the up counter 52, and the print timing pulse TP4 is output.
[0014]
The comparator 58 compares the outputs Q0 to Q7 of the up counter 52 with the outputs Q0 to Q7 of the latch circuit 54. That is, the value of 4/4 of the measured reference position interval T1 is compared with the value of the up counter 52, and the print timing pulse TP5 is output. Then, by inputting the coincidence detection output of the comparator 58 to the load terminal of the up counter 52, generation of the next timing pulse train is started.
[0015]
As described above, the up counter 52 and the comparators 55 to 58 constitute a printing timing pulse train generating means. The quarter and quarter divisions are realized by 2-bit shift and 1-bit shift, respectively. Further, the division by three quarters is realized by adding a 2-bit shift and a 1-bit shift. The outputs of the comparators 55 to 58 are gated by the reset bar signal by the 2-input AND gates 60 to 63 and input to the 4-input OR gate 63.
[0016]
With the configuration described above, first, coincidence detection is output from the comparator 58 in synchronization with the reference position pulse BP2, whereby the print timing pulse TP1 is output from the 4-input OR gate 63. Subsequently, coincidence detection is output from the comparator 55 at a timing that is ¼ of the reference position interval T 1, whereby the print timing pulse TP 2 is output from the 4-input OR gate 63. Subsequently, coincidence detection is output from the comparator 56 at a timing of 2/4 of the reference position interval T1, whereby the print timing pulse TP3 is output from the 4-input OR gate 63. Subsequently, coincidence detection is output from the comparator 57 at the timing of 3/4 of the reference position interval T1, and accordingly, the print timing pulse TP4 is output from the 4-input OR gate 63. Subsequently, coincidence detection is output from the comparator 58 at the timing of 4/4 of the reference position interval T1, and thereby the print timing pulse TP5 is output from the 4-input OR gate 63. Here, the timing of TP5 does not necessarily coincide with the timing of BP3.
[0017]
In this way, the up counter 52 is always restarted while maintaining the pulse intervals of the previous reference position intervals T1, T2, T3,... Loaded into the latch circuit 54, and always from the reference position pulse to the reference position intervals T1, T2. , T3... Therefore, the print timing pulse interval is narrowed by being forcibly restarted by the third and subsequent reference position pulses BP3, BP4, etc., and printing is not disabled when the number of divisions of the encoder output period is increased. .
[0018]
[Problems to be solved by the invention]
However, in the conventional technique described above, a good printing result can be obtained when printing is performed while the carriage 2 is moving at a substantially constant speed, for example, when there is a speed fluctuation of plus or minus several percent with respect to the constant speed. However, a problem occurs when printing is performed while the moving speed of the carriage 2 is accelerated and bidirectional printing is performed.
[0019]
For example, a print timing pulse is generated at a timing when the encoder output is divided into two, printing is started while the carriage 2 is accelerated, and a vertical ruled line is printed at the position of the fifth print timing pulse from the print start position. The bidirectional printing will be described.
[0020]
FIG. 21 shows the output position relationship between the encoder output, the reference position pulse Load1, and the print timing pulse for the monochrome print pattern printed on the linear scale 4. One cycle (a pair of white and black) of the print pattern of the linear scale 4 is widened or narrowed because the cycle of the print pattern is not changing but the moving speed of the carriage 2 is It shows that it is changing. That is, a portion where the cycle length of the print pattern is gradually shortened indicates that the carriage 2 is accelerating, and a portion where the length of the cycle of the print pattern is gradually increased is that the carriage 2 is It shows that it is decelerating. The output of the encoder is synchronized with the printing pattern of the linear scale 4.
[0021]
In FIG. 21, the direction from left to right in the figure is defined as the forward direction, and the direction from right to left is defined as the reverse direction. Since the forward printing is performed from the left to the right, the reference position pulse is generated four times from BP1 to BP4. The intervals between the reference position pulses are (T + 3a) time between BP1 and BP2, (T + 2a) time between BP2 and BP3, and (T + a) time between BP3 and BP4. Print timing pulses in forward printing are generated seven times from TP1 to TP7.
[0022]
If a vertical ruled line is printed at the position of the fifth print timing pulse TP5, dots are printed at the position of TP5. At this time, as shown in FIG. 22, the position where the dot is originally intended to be printed is the position on the left side in the period of T time in the encoder output, whereas the actually printed dot is 2a from the place. The position is shifted in the forward direction by time. This is because, in printing while the carriage 2 is accelerating, the time LF to the originally printed position is ((T + 2a) + (T + a)) from the BP2 at the print start position. The time PF to the actual printing position is ((T + 3a) + (T + 2a)) from the BP2 at the printing start position, which is because the latter is longer by 2a.
[0023]
On the other hand, at the time of reverse printing, the reference position pulse is generated four times from BP11 to BP14. In FIG. 21, since reverse printing is performed from right to left, the reference position pulse occurs first at BP11 and last at BP14. The intervals between the reference position pulses are (T + 3a) time between BP11 and BP12, (T + 2a) time between BP12 and BP13, and (T + a) time between BP13 and BP14. The printing timing pulse in the reverse printing is generated seven times from TP11 to TP17.
[0024]
Since the vertical ruled line is printed at the left position in the period of T time by the encoder output, the dot is printed at the position of the sixth printing timing pulse TP16. However, the dots that are actually printed at this time are positions that are shifted in the reverse direction by 2.5 a hours from the positions. This is because, in printing while the carriage 2 is accelerating, the time LR until the original printing position is ((T + 2a) + (T + a) + T / 2) from the BP 12 at the printing start position. The time PR until the printing position is ((T + 3a) + (T + 2a) + (T / 2 + a / 2)) from the BP2 at the printing start position, and the latter is 2.5a longer. caused by.
[0025]
After all, when the vertical ruled line is printed while the carriage 2 is accelerating, the forward printing is shifted by 2a hours in the forward direction, and the backward printing is shifted by 2.5a hours in the reverse direction, as shown in FIG. This results in the printing of vertical ruled lines with uneven steps. The example described here is a vertical ruled line. However, even when printing a general image or character, if printing is performed while the carriage 2 is accelerating, printing with the carriage moving in the forward direction is similarly performed. In printing while all the dots are shifted from the forward direction with respect to the encoder output and moving in the reverse direction, all the dots are shifted from the reverse direction with respect to the encoder output.
[0026]
The reason why such a problem occurs is that the print timing generation circuit in the conventional printer control apparatus assumes only that the carriage prints at a constant speed.
[0027]
SUMMARY OF THE INVENTION An object of the present invention is to provide a printer control device that provides high-quality print results in an inkjet printer. In particular, whether the carriage is printing while accelerating or printing at a constant speed, it is possible to print well, and even when printing in both directions, the carriage is accelerating and printing at a constant speed. There is to be able to do it.
[0028]
The present inventionThe printer control device is an ink jet printer control device including an encoder that outputs an electrical signal for generating a printing timing for ejecting ink droplets from a print head mounted on a carriage.
A first printing timing generation circuit; a second printing timing generation circuit; and a switching circuit that switches between the first printing timing generation circuit and the second printing timing generation circuit according to the output of the encoder. This switching circuit has the above-mentionedWhen the carriage movement speed is changingUsing the first print timing generation circuit,When the carriage movement speed is constantThe second print timing generation circuit is used, and the first print timing generation circuit measures a period of a reference position pulse output from the encoder by a first period counter, and measures the time by the first period counter. A first cycle time storage unit that holds the measured time, and an inverted output of the reference position pulse as an initial print timing pulse in the cycle, and the time stored in the first cycle time storage unit And a printing timing pulse circuit for generating a subsequent printing timing pulse based on the timing of the time stored in the first cycle time storage unit. 1 / N At the timing N Generate print timing pulses 1 / N A divider and said 1 / N The printing timing pulse from the divider is ( N − 1 ) Once output N The second time 1 / N A mask circuit for masking the output of the divider, wherein the second print timing generation circuit counts a period of a reference position pulse output from the encoder, and the second period counter The second cycle time storage unit that keeps the time measured in step 2 and the cycle time stored in the second cycle time storage unit are timed and the time measurement is resumed when the time measurement is completed. And generating a print timing pulse by multiplying the cycle time stored in the second cycle time storage unit based on the time counted by the third cycle counter.It is characterized by that.
[0030]
Specifically, the printer control apparatus according to the present invention includes a carriage (2 in FIG. 18) on which a print head (1 in FIG. 18) is mounted, a motor (3 in FIG. 18) for moving the carriage, and movement of the carriage. A printer control apparatus in an ink jet printer having an encoder (11 in FIG. 1) that outputs pulses synchronously, and an A print timing generation circuit (FIG. 1) that generates a print timing pulse based on an output signal from the encoder 12) and B printing timing generation circuit (13 in FIG. 1) (14 in FIG. 1).
[0031]
For this reason, there is a problem when the carriage movement speed is constant, compared to the case where printing is performed using the same print timing generation circuit both when the carriage movement speed is accelerating and constant. Although there is a problem with the A print timing generation circuit that can obtain good print results during acceleration and the B print timing that can obtain good print results during constant speed, there is a problem while the carriage moving speed is accelerating. The circuit can be switched and used, and as a result, a high-quality printing result can be obtained.
[0032]
The number of print timing generation circuits may be three or more, and the timing for switching the print timing generation circuit may be any of accelerating, constant speed, and decelerating, and the number of times the print timing generating circuit is switched is limited to one. Absent.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
The printer control device of the present invention is a printer control device in an ink jet printer that includes an encoder that outputs an electrical signal for generating a print timing for ejecting ink droplets from a print head, each based on the electrical signal. However, the present invention is characterized in that at least two or more print timing generation means for generating print timings with different algorithms are provided, and means for switching and using the print timing generation means during printing depending on the printing conditions is provided.
[0034]
【Example】
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0035]
[Target inkjet printers]
The ink jet printer to be controlled by the printer control apparatus of the present invention is as shown in FIG. In this ink jet printer, in FIG. 15, the carriage 2 on which the print head 1 is mounted reciprocates across the recording medium 6, and at this time, printing is performed by ejecting ink droplets from the print head 1. Usually, a motor 3 is used to reciprocate the carriage 2. The reciprocating motion of the carriage 2 is realized by converting the rotational motion of the motor 3 into the linear motion of the carriage 2 by a mechanism not shown and switching the rotational direction of the motor 3.
[0036]
Here, a linear encoder 7 including a linear scale 4 and an optical sensor 5 is used for position control and movement speed control of the carriage 2. The linear scale 4 is installed in parallel with the reciprocating direction of the carriage 2. The optical sensor 5 detects the pattern printed on the linear scale 4, converts it into an electrical signal, outputs it, and controls the motor 3 based on this to perform the above-described position control and movement speed control of the carriage 2. . An important function of the linear encoder 7 is the generation of printing timing (timing for ejecting ink droplets).
[0037]
The encoder other than the linear encoder 7 has a wheel that is fixed to the motor shaft or gear shaft and rotates together with the motor or gear. The pattern printed on the wheel is detected by an optical sensor, and is converted into an electric signal. A rotary encoder that converts and outputs is known.
[0038]
[Example Overview]
FIG. 1 is a block diagram of a print timing generation apparatus for an ink jet printer, which is an embodiment of a printer control apparatus of the present invention. In FIG. 1, the printing timing generator includes an encoder 11, an A printing timing generation circuit 12, a B printing timing generation circuit 13, and an A printing timing generation that output an electrical signal in synchronization with the printing pattern of the linear scale 4. A switching circuit 14 for switching between the circuit 12 and the output of the B print timing generation circuit 13 is configured.
[0039]
The encoder 11 performs the same function as the linear encoder 7 in FIG. That is, the print pattern printed on the linear scale 4 is detected, converted into an electrical signal and output, and the motor 3 is controlled based on the detected pattern, thereby controlling the position and the moving speed of the carriage 2. Also, printing timing (timing for ejecting ink droplets) is generated.
[0040]
The A print timing generation circuit 12 has a problem when, for example, the carriage 2 is moving at a constant speed, but generates a print timing such that a good print result can be obtained during acceleration. Therefore, it is selected when the carriage 2 is accelerating. However, the print timing characteristics and selection criteria for the A print timing generation circuit 12 are merely described as examples, and are not limited thereto. However, it is naturally different from the B print timing generation circuit 13.
[0041]
The B print timing generation circuit 13 has a problem when the carriage 2 is accelerating, for example, but generates a print timing such that a good print result can be obtained while moving at a constant speed. Therefore, it is selected when the carriage 2 is moving at a constant speed. However, the print timing characteristics and selection criteria for the B print timing generation circuit 13 are merely described as examples, and are not limited thereto. However, it is naturally different from the A print timing generation circuit 12.
[0042]
The switching circuit 14 selects, based on the output of the encoder 11, for example, the output of the A print timing generation circuit 12 when the carriage 2 is accelerating and the output of the B print timing generation circuit 13 while the carriage 2 is moving at a constant speed. Switch to. However, this characteristic for the switching circuit 14 is only described as an example, and is not limited thereto.
[0043]
FIG. 2 is a diagram showing the carriage moving speed and the print timing generation circuit switching timing in the first embodiment of the present invention. The ink jet printer starts rotation of the motor 3 in response to a print start command, and accelerates the moving speed of the carriage 2 toward the target speed. When the carriage 2 reaches a preset printing start position during acceleration, printing is started. Thereafter, when the carriage 2 reaches the target speed, the motor control is performed so that the moving speed of the carriage 2 always matches the target speed. Here, the motor 3 is controlled so as to have a constant speed, but the carriage 2 does not actually move at a constant speed, and moves while varying the speed within a range of plus or minus several percent of the target speed. To go. The output signal of the encoder 11 is the basis of the carriage position and movement speed control.
[0044]
FIG. 3 is a diagram illustrating the relationship between the print pattern (linear scale pattern) printed on the linear scale 4 and the electrical signals (encoder A-phase output and encoder B-phase output) output from the encoder 11. The linear scale 4 is created by printing black ink on a transparent plastic material. Transparent portions on which ink is not printed and black printed portions are alternately arranged, and a pair of a transparent portion and a black portion has a certain length. Here, it is about 169 μm (equivalent to 150 dpi). The encoder A phase output is synchronized with the linear scale pattern, and outputs a high level when the linear scale 4 is transparent, and outputs a low level when it is black. The encoder B phase output is 90 degrees out of phase with the encoder A phase output. The encoder A phase output is used for various controls. The encoder B phase output is used only for determining the printing direction. If the encoder A phase output is advanced, the forward printing is performed, and if the encoder B phase output is advanced, the backward printing is performed.
[0045]
In FIG. 2, when the carriage 2 reaches a preset print start position during acceleration, printing is started. At this time, the switching circuit 14 obtains a good print result even when the carriage prints during acceleration. A print timing generation circuit 12 to be selected is selected. Therefore, printing is started by the print timing pulse generated by the A print timing generation circuit. After that, when the carriage moving speed reaches the target speed, the switching circuit 14 indicates that the carriage fluctuates at a constant speed (here, “constant speed” is a speed fluctuation of plus or minus several percent of the target speed. The print timing generation circuit 3 is switched to the B print timing generation circuit 3 which can obtain a good print result when printing is performed in order to generate a print timing pulse.
[0046]
[Details of Examples]
For example, as shown in FIG. 4, the A print timing generation circuit 12 includes a cycle counter 21, a cycle time storage unit 22, and a print timing pulse circuit 23. The print timing pulse circuit 23 further includes a 1/4 divider 24 and a mask. It consists of a circuit 25. In this example, the output cycle of the encoder 11 is divided into four. In FIG. 4, the cycle counter 21 counts the cycle of the encoder A phase output, and the cycle time storage unit 22 holds the time counted by the cycle counter 21. The print timing pulse circuit 23 generates an A print timing pulse based on the time stored in the cycle time storage unit 22. The ¼ divider 24 constituting the printing timing pulse circuit 23 generates an A printing timing pulse at a ¼ timing of the time stored in the cycle time storage unit 22, and the mask circuit 25 divides the ¼ division. When the A print timing pulse is output three times from the unit 24, the output of the 1/4 divider 24 is masked.
[0047]
FIG. 5 is a timing chart of the A print timing generation circuit 12 of FIG. The reference position pulse is a signal output at a timing when the pattern of the linear scale 4 changes from a black portion to a transparent portion. In FIG. 5, the reference position pulse is output in synchronization with the rising edge of the encoder A phase output. Printing is started at the timing of the reference position pulse BP2.
[0048]
The cycle counter 21 starts timing at the timing of the reference position pulse BP1, and at the timing of BP2, it measures the time T1 between the BP1 and BP2, and the cycle time storage unit 22 stores the time T1. At the same time, the period counter 21 starts timing between the next reference position pulses.
[0049]
At the timing of BP2, the cycle time storage unit 22 stores the time T1 and simultaneously outputs the time T1 to the print timing pulse circuit 23. In the printing timing pulse circuit 23, the input time T1 is divided by 4 by a quarter divider by four. The quarter divider 24 outputs a printing timing pulse when it measures a quarter of the time T1. Further, when the time of 1/4 of the time T1 is measured, the next printing timing pulse is output. In this way, the 1/4 divider 24 repeats outputting the print timing pulse at a time that is a quarter of the input time.
[0050]
The mask circuit 25 enables the output of the 1/4 divider 24 by the reference position pulse, counts the number of printing timing pulses that are the output of the 1/4 divider, and counts the number of times to 3 to output the 1/4 divider 24. Mask the output.
[0051]
The print timing pulse circuit 23 takes the logical sum of the print timing pulses TP2 to TP4 output from the 1/4 divider 24 generated internally and the print timing pulse TP1 generated by inverting the reference position pulse, and outputs A Print timing pulse is output. As described above, in printing using the A print timing generation circuit 12, the 1/4 divider output signal employs a signal that is one less than the number of divisions for the output period of the encoder 11 as the A print timing pulse. A reference position pulse is adopted at the head of the print timing pulse.
[0052]
Each time the reference position pulse is input, the above-described operation is repeated, whereby the output of the A printing timing pulse is also repeated. Then, ink is ejected from the print head 1 based on the timing of the print timing pulse, and printing on the recording medium 6 is performed.
[0053]
Since printing using the A print timing generation circuit 12 is performed while the movement speed of the carriage 2 is accelerated, the interval between the reference position pulses is wider than that at a constant speed. Therefore, since the interval time of the print timing pulses generated by dividing the reference position pulses is longer than the period determined by the response frequency of the print head, printing does not become impossible.
[0054]
For example, as shown in FIG. 6, the B print timing generation circuit 13 includes an A period counter 31, a B period counter 32, a period time storage unit 33, a 1/4 divider 34, a 2/4 divider 35, and a 3/4 division. It comprises a device 36, a 4/4 divider 37, a latch circuit 38 and a 4-input OR gate 39. This example is also for the case where the output cycle of the encoder 11 is divided into four, similarly to the A print timing generation circuit 12 shown in FIG.
[0055]
The A cycle counter 31 starts counting the cycle of the encoder A phase output by the reference position pulse, is cleared by the next reference position pulse, and starts counting again. The cycle time storage unit 33 holds the time counted by the A cycle counter 31. The B cycle counter 32 is also a counter that measures the cycle of the encoder A phase output. The difference between the A cycle counter 31 and the B cycle counter 32 is that the A cycle counter 31 resumes timing by the reference position pulse, whereas the B cycle counter 32 counts the time stored in the cycle time storage unit 33. It is cleared when it finishes, and it is to resume timing.
[0056]
The 1/4 divider 34 outputs a printing timing pulse when 1/4 of the time stored in the cycle time storage unit 33 matches the time counted by the B cycle counter 32. The 2/4 divider 35 outputs a printing timing pulse when 2/4 of the time stored in the cycle time storage unit 33 coincides with the time counted by the B cycle counter 32. The 3/4 divider 36 outputs a print timing pulse when 3/4 of the time stored in the cycle time storage unit 33 coincides with the time counted by the B cycle counter 32. The 4/4 divider 37 outputs a print timing pulse when the time stored in the cycle time storage unit 33 coincides with the time counted by the B cycle counter 32. However, the time counted by the B period counter 32 is input to the input of the 4/4 divider 37 when the print timing pulse is output from the 3/4 divider 37.
[0057]
When the print timing pulse is output from the 3/4 divider 36, the latch circuit 38 outputs the time counted by the B period counter 32 to the 4/4 divider 37. The output of the 4/4 divider 37 is also input to the B cycle counter 32, clears the cycle counter B132, and is also used as a trigger for restarting timing. The 4-input OR gate 39 receives the print timing pulse output from the 1/4 divider 34, 2/4 divider 135, 3/4 divider 36 or 4/4 divider 37 and outputs the B print timing pulse. To do.
[0058]
FIG. 7 is a timing chart of the B print timing generation circuit B of FIG. FIG. 7 shows that the A print timing generation circuit 12 switches to the B print timing generation circuit 13 at the timing of the reference position pulse BP12, and printing by the B print timing generation circuit 13 starts.
[0059]
The A cycle counter 31 starts timing at the timing of the reference position pulse BP11, and measures the interval time T11 between BP11 and BP12 at the timing of BP12. At the timing of BP12, the cycle time storage unit 33 stores time T11. At the same time, the A cycle counter 31 starts timing between the next reference position pulses.
[0060]
At the timing of BP12, the cycle time storage unit 33 stores the time T11 and at the same time outputs the time T11 to the 1/4 divider 34, the 2/4 divider 35, the 3/4 divider 36, and the latch 38. The output of the B period counter 32 is input to the ¼ divider 34, the 2/4 divider 35, the 3/4 divider 36, and the 4/4 divider 37. When the B cycle counter 32 measures ¼ of the time T11, the ¼ divider 34 outputs a print timing pulse TP1. Similarly, when the B cycle counter 32 measures 2/4 of the time T11, the print timing pulse TP2 is output from the 2/4 divider 35, and when the B cycle counter 32 counts 3/4 of the time T11, 3 / A print timing pulse TP3 is output from the four-divider 36.
[0061]
When TP3 is output, the time T11 stored in the cycle time storage unit 33 is input from the latch circuit 38 to the 4/4 divider 37. When the B cycle counter 32 measures 4/4 of the time T11, the print timing pulse TP4 is output from the 4/4 divider 37. The print timing pulse TP4 is also input to the B cycle counter 32, and the B cycle counter 32 is cleared and restarts timing. Here, the timing of TP4 does not necessarily coincide with the timing of BP3.
[0062]
In this way, the B period counter 32 is always restarted while maintaining the previous reference position intervals T11, T12, T13... Stored in the period time storage unit 33, and always the first reference position interval from the reference position pulse. It is restarted with a delay of T11. Therefore, it is not forcibly restarted by the third and subsequent reference position timing pulses BP3, BP4,.
[0063]
For example, as shown in FIG. 8, the switching circuit 14 includes a switching position register 41, a position counter 42, a printing start position register 43, a switching position detection circuit 44, a printing start position detection circuit 45, a selector 46, and a two-input AND gate 47. Composed.
[0064]
The switching position register 41 is a register that stores a position at which the A printing timing pulse and the B printing timing pulse are switched by the number of encoder outputs, and is set at a position to be switched before printing is started.
[0065]
The position counter 42 counts the output of the encoder 11 of FIG. 1, and outputs the position of the carriage 2 as the number of encoder outputs.
[0066]
The print start position register 43 is a register that stores the position at which the inkjet printer starts printing by the number of encoder outputs, and the print start position is set before printing is started. In this embodiment, since the A print timing generation circuit 12 is selected at the print start position, the A print timing pulse is also a position at which output starts.
[0067]
The switching position detection circuit 44 compares the value set in the switching position register 41 with the value of the carriage position from the position counter 42, and changes the PCchange signal from low level to high level if they match.
[0068]
The print start position detection circuit 45 compares the value set in the print start position register 43 with the value of the carriage position from the position counter 42, and changes the PEEnable signal from low level to high level if they match.
[0069]
The selector 46 receives the A print timing pulse from the A print timing generation circuit 12 and the B print timing pulse from the B print timing generation circuit 13. The output PCchange signal of the switching position detection circuit 44 is input to the SEL terminal. When the PCchange signal is at a low level, an A print timing pulse is output, and when the PCChange signal is at a high level, a B print timing pulse is output. .
[0070]
The 2-input AND gate 47 has one input terminal connected to the output of the selector 46 and the other input terminal connected to the PEEnable signal that is the output of the print start position detection circuit 45. When the PEEnable signal is at a high level, the output of the selector 46 is output as a print timing pulse.
[0071]
FIG. 9 is a timing chart of the switching circuit 14 shown in FIG. Here, when the value of the position counter 42 starts printing from 101, the printing ends at 110, and when the value of the position counter 42 reaches 106, the printing timing pulse is output by the A printing timing generation circuit 12. The case where the A print timing pulse is switched to the B print timing pulse output from the B print timing generation circuit B is shown. That is, when the value of the position counter 42 is 101 to 106, the carriage 2 is accelerating, and when the value of the position counter 42 is 106 to 110, the carriage 2 is moved at a constant speed. .
[0072]
In FIG. 9, the encoder A phase output output from the encoder 11 is input to the position counter 42, and the value of the position counter 42 is counted up at the rising edge of the encoder A phase output. When the value of the position counter 42 reaches 101, it matches the value 101 previously set in the print start position register 43, so the print start position detection circuit 45 changes the PEEnable signal from low level to high level. The value of the position counter 42 counted up at the rising edge of the encoder A-phase output is also input to the switching position detection circuit 44, and the value 106 previously set in the switching position register 41 as the count-up proceeds. If it matches, the switching position detection circuit 44 changes the PCChange signal from the low level to the high level.
[0073]
When the value of the position counter 42 becomes 101, the PEEnable signal becomes high level and the 2-input AND gate 47 is enabled. At this time, since the SEL terminal of the selector 46 is at a low level, the output of the selector 46 becomes an A printing timing pulse, and the output of the 2-input AND gate 47 also becomes an A printing timing pulse. As a result, the A printing timing pulse is selected as the printing timing pulse.
[0074]
When the value of the position counter 42 further advances and the value of the position counter 42 reaches 106, the PCchange signal becomes high level, and since the selector 46 has the SEL terminal at high level, the output is a B printing timing pulse. Since the 2-input AND gate 47 is still enabled, the printing timing pulse from the position where the position counter value is 106 becomes the B printing timing pulse, and the printing timing pulse is switched. As it is, printing is performed by the B printing timing pulse that is the output of the B printing timing generation circuit, and when the designated number of printing dots is completed or printing of the designated printing range is finished, the switching circuit 44 returns to the initial state. Thus, the printing timing pulse is not output.
[0075]
Here, the switching circuit 44 is an embodiment in which the print timing generation circuit is switched at a preset position. However, the carriage moving speed is monitored, and it is detected that the carriage has reached a constant speed, and the print timing generation circuit is switched. There is also a method.
[0076]
[Verification of defect resolution]
Based on FIG. 10, FIG. 11, and FIG. 12, it is verified that the problems shown in FIGS. As in FIG. 21, a print timing pulse is generated at a timing when the encoder output is divided into two, printing is started during acceleration of the carriage, and vertical ruled lines are printed at the position of the fifth print timing pulse from the print start position. And
[0077]
FIG. 10 shows an output positional relationship between an encoder output, a reference position pulse Load1 signal, and a printing timing pulse when the present invention is applied to a monochrome pattern printed on a linear scale. One cycle (a pair of white and black) of the print pattern of the linear scale 4 is widened or narrowed because the cycle of the print pattern is not changing but the moving speed of the carriage 2 is It shows that it is changing. That is, the part where the linear scale period is gradually shortened indicates that the carriage 2 is accelerating, and the part where the print pattern period is gradually increased is the part where the carriage 2 is accelerated. It shows that it is decelerating. The encoder output is synchronized with the linear scale pattern.
[0078]
In FIG. 10, the direction from left to right in the figure is defined as the forward direction, and the direction from right to left is defined as the reverse direction. Since forward printing is performed from left to right, the reference position pulse is generated five times from BP1 to BP5. The intervals between the reference position pulses are (T + 3a) time between BP1 and BP2, (T + 2a) time between BP2 and BP3, (T + a) time between BP3 and BP4, and (T + a) time between BP4 and BP5. ) Time. Print timing pulses in forward printing are generated 8 times from TP1 to TP8.
[0079]
If a vertical ruled line is printed at the position of the fifth print timing pulse TP5, dots are printed at the position of TP5. This position coincides with the position of the reference position pulse BP4, which is originally the position where the dot is to be printed. In the present invention, the mask circuit 25 masks the final print timing in the cycle, and the print timing generation circuit 23 inverts the reference position pulse BP3 as the print timing pulse TP3 and the reference position pulse BP4 as the print timing pulse TP5. This is due to the output of inversion.
[0080]
On the other hand, at the time of reverse printing, the reference position pulse is generated five times from BP11 to BP15. In FIG. 10, since reverse printing is performed from right to left, the reference position pulse is generated first at BP11 and last at BP15. The intervals between the reference position pulses are (T + 3a) time between BP11 and BP12, (T + 2a) time between BP12 and BP13, (T + a) time between BP13 and BP14, and (T + a) time between BP14 and BP15. ) Time. Print timing pulses in reverse printing are generated 8 times from TP11 to TP18.
[0081]
Since the vertical ruled line is printed at the left position in the period of T time by the encoder output, the dot is printed at the position of the sixth printing timing pulse TP16. However, the dots that are actually printed at this time are positions that are shifted in the reverse direction by 0.5 a hours from the positions. This is because, in printing while the carriage 2 is accelerating, the time LR until the original printing position is ((T + 2a) + (T + a) + T / 2) from the BP 12 at the printing start position. The time PR until the printing position is from the reference position pulse BP14 to the printing start position BP12 ((T + 2a) + (T + a) + (T / 2 + a / 2)). Increases by 5a hours.
[0082]
As described above, in the conventional technology, the forward printing is delayed by 2a hours in the forward direction, and the reverse printing is delayed by 2.5a hours in the reverse direction. Therefore, as shown in FIG. Therefore, a vertical ruled line with a step as shown in FIG. 23 was printed. However, in the printer to which the present invention is applied, no deviation occurs in the forward printing as described above. In reverse printing, the printing is delayed by 0.5a hours in the reverse direction, but the printing result can be obtained with no difference in level as shown in FIG. The example described here is the case of vertical ruled line printing. However, according to the present invention, even when printing a general image or character, even if the carriage is printing while accelerating, forward printing and reverse printing are performed. There is little misalignment, and good printing results can be obtained.
[0083]
Other Embodiments of the Invention
FIG. 13 is a diagram for explaining a second embodiment of the present invention. In this embodiment, the timing at which the switching circuit 14 switches from the A printing timing generation circuit 12 to the B printing timing generation circuit 13 is that the carriage 2 is accelerating, and FIG. 13 shows the carriage moving speed and the printing timing generation circuit switching timing in that case. This shows the relationship. This is because, as shown in FIG. 2, if the print timing generation circuit is switched at the moment when the movement of the carriage 2 reaches a constant speed from the acceleration, the movement of the carriage 2 is actually delayed due to inertia. In consideration of the fact that the desired printing timing cannot be obtained, the countermeasure is taken.
[0084]
There is another reason for switching the print timing generation circuit even when the carriage 2 is accelerating. As shown in FIG. 17, when printing an image in which characters and pictures are mixed, a print timing generation circuit with a high resolution and a small gradation value is used in the range where characters are printed, and the resolution is low in the range where pictures are printed. Another print timing generation circuit having a large gradation value is used. By doing so, high-quality printing can be performed over the entire image. Thus, the present invention is intended to perform high-quality printing, and does not limit the switching factor of the print timing generation circuit to the carriage moving speed or the like.
[0085]
FIG. 14 is a diagram for explaining a third embodiment of the present invention. In this embodiment, the timing at which the switching circuit 14 switches from the A print timing generation circuit 12 to the B print timing generation circuit 13 is after the carriage 2 has reached a constant speed, and FIG. 14 shows the carriage movement speed and print timing generation in that case. It shows the relationship with circuit switching timing. The significance of this embodiment is the same as that of the second embodiment. That is, depending on the variation of the parts, it may be necessary to switch from the point of acceleration to a point after reaching a constant speed in order to obtain a desired printing timing, and the boundary between the character and the picture is the speed of the carriage 2. This is because there is a possibility that the speed is constant.
[0086]
As described above, in the second and third embodiments, the print timing generation circuit switching timing is not coincident with the timing at which the moving speed of the carriage 2 changes from acceleration to a constant speed. .
[0087]
FIG. 15 is a diagram for explaining a fourth embodiment of the present invention. In this embodiment, the A print timing generation circuit is used while the carriage 2 is accelerating, the B timing generation circuit is used during a constant speed, and the third C print timing generation circuit is used during deceleration. FIG. 15 shows the relationship between the carriage movement speed and the print timing generation circuit switching timing in this case. This is because the printing timing is generated under the same control as during acceleration even during deceleration for the same reason that printing timing different from that during constant speed is required during acceleration.
[0088]
FIG. 16 is a diagram for explaining a fifth embodiment of the present invention. In this embodiment, the carriage 2 is switched from the D printing timing generation circuit D to the printing timing generation circuit during acceleration, and the carriage moving speed and the printing timing generation circuit switching timing when the B printing timing generation circuit is used during a constant speed. It is the figure which showed the relationship. As is apparent from FIGS. 15 and 16, the number of print timing generation circuits to be switched is not limited to two.
[0089]
As mentioned above, although the Example of this invention has been described, this invention is not limited to these, A further many Example is guide | induced by combining the above-mentioned Example. For example, the combination of the first embodiment (FIG. 2) and the third embodiment (FIG. 14), the combination of the second embodiment (FIG. 13) and the third embodiment (FIG. 14), the second embodiment (FIG. 13). And switching during deceleration (adoption of C printing timing generation circuit), combined use of the second embodiment (FIG. 13) and fourth embodiment (FIG. 15), third embodiment (FIG. 14) and fourth embodiment ( 15), a combination of the third embodiment (FIG. 14) and switching during deceleration (adoption of the C printing timing generation circuit), a combination of the third embodiment (FIG. 14) and the fifth embodiment (FIG. 16), This is a combination of the fourth embodiment (FIG. 15) and the fifth embodiment (FIG. 16).
[0090]
【The invention's effect】
The effect of the present invention is that at least two printing timing generation means that can obtain good printing results under limited conditions in an ink jet printer are provided and used by switching according to the printing conditions. And good printing corresponding to the image condition to be printed.
[0091]
In particular, it has a print timing generation circuit that can obtain good print results while the carriage is accelerating and a print timing generation circuit that can obtain good print results while the carriage is at a constant speed. Since the switching means is provided, good printing results can be obtained even when the carriage prints both during acceleration and at a constant speed. This effect does not change even during bidirectional printing.
[Brief description of the drawings]
FIG. 1 is a block diagram of a printer control apparatus according to the present invention.
FIG. 2 is a diagram showing a carriage moving speed and a printing timing generation circuit switching timing in the first embodiment of the present invention.
FIG. 3 is a diagram showing a relationship between a print pattern printed on a linear scale and an encoder output signal.
FIG. 4 is a detailed diagram of an A print timing generation circuit according to the first embodiment of the present invention.
FIG. 5 is a timing chart of the A print timing generation circuit shown in FIG.
FIG. 6 is a detailed diagram of a B print timing generation circuit according to the first embodiment of the present invention.
7 is a timing chart of the B print timing generation circuit shown in FIG.
FIG. 8 is a detailed diagram of the switching circuit in the first embodiment of the present invention.
9 is a timing chart of the switching circuit shown in FIG.
FIG. 10 is a timing chart at the time of bidirectional printing during carriage acceleration of the print timing generation circuit shown in FIG.
FIG. 11 is a diagram showing the positions of dots to be printed based on the print timing results shown in FIG.
12 is a diagram showing a result of printing vertical ruled lines as the set of dots shown in FIG.
FIG. 13 is a diagram showing carriage movement speed and print timing generation circuit switching timing for explaining a second embodiment of the present invention;
FIG. 14 is a diagram showing carriage movement speed and print timing generation circuit switching timing for explaining a third embodiment of the present invention;
FIG. 15 is a diagram showing carriage movement speed and print timing generation circuit switching timing for explaining a fourth embodiment of the present invention;
FIG. 16 is a diagram showing carriage movement speed and print timing generation circuit switching timing for explaining a fifth embodiment of the present invention;
FIG. 17 is a diagram illustrating a print range of a print timing generation circuit when printing an image in which characters and pictures are mixed;
FIG. 18 is a configuration diagram of a general inkjet printer to which the present invention is applied.
FIG. 19 is a timing chart of a conventional print timing generation circuit.
20 is a detailed diagram of a conventional print timing generation circuit that generates the print timing shown in FIG.
FIG. 21 is a timing chart at the time of bidirectional printing during carriage acceleration of the print timing generation circuit shown in FIG.
22 is a diagram showing the positions of dots to be printed based on the result of the printing timing shown in FIG.
23 is a diagram showing a result of printing vertical ruled lines as the set of dots shown in FIG.
[Explanation of symbols]
1 Print head
2 Carriage
3 Motor
4 Linear scale
5 Optical sensors
6 print media
7 Linear encoder
11 Encoder
12 A print timing generation circuit
13 B printing timing generation circuit
14 switching circuit
21 Period counter
22 Period time memory
23 Print timing pulse circuit
24 1/4 divider
25 Mask circuit
31 A period counter
32 N period counter
33 Period time memory
34 1/4 divider
35 2/4 divider
36 3/4 divider
37 4/4 divider
38 4 input OR gate
39 Latch circuit
41 Switching position register
42 Position counter
43 Print start position register
44 Switching position detection circuit
45 Print start position detection circuit
46 selector
47 2-input AND gate
51,52 up counter
53, 54 Latch circuit
55-58 comparator
59 3/4 divider
60-63 2-input AND gate
64 4-input OR gate

Claims (5)

A printer control device in an inkjet printer including an encoder that outputs an electrical signal for generating a printing timing for ejecting ink droplets from a print head mounted on a carriage,
A first print timing generation circuit;
A second print timing generation circuit;
A switching circuit that switches between the first print timing generation circuit and the second print timing generation circuit according to the output of the encoder;
The switching circuit uses the first print timing generation circuit when the carriage movement speed is changing, and uses the second print timing generation circuit when the carriage movement speed is constant. ,
The first print timing generation circuit includes:
A first period counter for measuring the period of the reference position pulse output by the encoder;
A first cycle time storage unit for holding the time counted by the first cycle counter;
A print timing pulse circuit that outputs an inverted output of the reference position pulse as an initial print timing pulse in the cycle and generates a subsequent print timing pulse based on the time stored in the first cycle time storage unit; Configured,
Furthermore, the printing timing pulse circuit includes:
A 1 / N divider for generating N printing timing pulses at a timing of 1 / N of the time stored in the first cycle time storage unit;
Have a mask circuit for masking the output of the 1 / N the print timing pulse from the divider is (N-1) times the output N-th of the 1 / N divider,
The second print timing generation circuit includes:
A second period counter for measuring the period of the reference position pulse output from the encoder;
A second cycle time storage unit for holding the time counted by the second cycle counter;
A third cycle counter that counts the cycle time stored in the second cycle time storage unit and restarts timing when the cycle time has been measured,
A printer control device that generates a printing timing pulse by multiplying a cycle time stored in the second cycle time storage unit based on a time counted by the third cycle counter . When said carriage is changed from being accelerated to constant speed, the printer control device according to claim 1, characterized in that switching to the second printing timing generation circuit from the first printing timing generation circuit. When said carriage is in a predetermined accelerating, the printer control device according to any one of the first printing timing generation circuit according to claim 1 or claim 2, characterized in that switching to the second printing timing generation circuit . When said carriage is in a predetermined in constant speed, a printer control according to any one of claims 1 to 3, characterized in that switching from the first printing timing generation circuit to the second print timing generating circuit apparatus. When said carriage is in a predetermined decelerating, the printer controller according to any one of claims 1 to 4, characterized in that switching to the first printing timing generation circuit from the second print timing generating circuit .

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