JPS63302058A - Frequency control system in ink jet printer - Google Patents

Abstract

PURPOSE:To synchronize the ink particle control with the space motor control to conduct a printing correctly, by a method wherein an oscillating frequency from a second oscillator is corrected by a reference frequency from a first oscillator when the power of a main control is ON. CONSTITUTION:According to a relation of a space resolving power being larger than a dot resolving power, the greatest common divisor is calculated. A microcomputer 11 conducts processing, such as a transfer from an input string buffer 10 to an image buffer 15 and the decision of a printing position, by using the greatest common divisor as a multiplier according to the change of the inputted printing data in character size, thereafter outputting a printing data. A printing is carried out after a carriage is moved a shortest distance either rightwards or leftwards. On the other hand, for the prevention of the occurrence of an accumulated error caused by the phase change-over of a space motor, which is a problem in this action, an output frequency which is outputted from a second oscillator 52a of a main control part 52 to control a whole printer is corrected by a reference clock frequency from a first oscillator 51a of an ink jet control part 51. In this manner, a printing can be conducted on a proper position from any of right and left positions and can be enhanced in speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a frequency control system for an inkjet printer, and particularly to correcting the frequency of a main control section by the frequencies of Infusiera 1 to the control section.

(Prior art) In conventional Infusiera 1 to printers, as a means of changing the printed character size, the charging voltage applied to ink droplets emitted from the head is changed, and the speed g of the space motor of the print carriage is changed. There are ways to change it.

In the above method, the printing period is constant and the space motor speed of the print carriage is changed to change the character size in the horizontal direction.
As shown in the figure, it is equipped with a home sensor 61 for detecting the home position of the carriage and a print start reference point, and a print start sensor 62 for detecting the home position of the carriage and a print start reference point. 12), the print carriage is returned to the home sensor 61 each time printing is performed, the home sensor 61 detects this, drives the space motor, and the print carriage comes to the position of the print start sensor 62 and starts printing. It was a unidirectional printing control that performed That is, when printing, it is necessary to always return to the home position and start printing, and the start sensor issues a print start command to print. For this reason, it was impossible to print at the shortest distance. In addition, in inkjet printers, the main control section and the inkjet control section use separate control oscillators, so when performing the shortest distance printing to the left and right, which is the objective of the present invention, There was an inconvenience.

(Problems to be Solved by the Invention) As described above, there is a limit to high-speed printing with unidirectional printing control in which the print carriage is always returned to the home sensor position when the character size changes.

The present invention solves these problems by changing the oscillation frequency of the main control unit when the carriage is returned to the home sensor position in the shortest distance in both left and right directions when the character size changes. The purpose is to perform correction using the stable oscillation frequency of the inkjet control unit, synchronize the control of ink particles and the control of the space motor, and perform printing accurately.

(Structure and operation) In order to achieve the above object, the present invention includes a first oscillator that generates a fundamental frequency and a second oscillator that performs main control, and when the main control is powered on, the second oscillator The present invention is characterized in that the oscillation frequency of the oscillator is corrected by the frequency of the first oscillator.

In addition, in order to print at the shortest distance in both left and right directions, an inkjet printer that can print multiple character sizes has a space resolution of S4 and a character size dot resolution of P□! pzl P3+...P,, Let M be the greatest common divisor of both resolutions, and let the multiplier that divides both resolutions by =3- be S Ill Pill pzl・
...Pn, until there is print data in the input string buffer, the multiplier for each character size is added until the print start position determination buffer contains the print data.
When the print data is available, determine the print start position and input the number of columns of print data to the print column counter.
In addition, the print data is transferred to the image buffer, and when there is no print data, the number of columns that are "absent" is counted in the space column counter, and when there is print data, the value of the space column counter is printed. It is characterized by adding the number of data columns to a print column counter and transferring the print data to an image buffer.

According to the present invention, in order to print at the shortest distance from left to right, we focused on the printing dot resolution of each character size and the space resolution due to the step angle of the stepping motor that operates the carriage, and made the printing period of one dot row constant. The relationship between each dot resolution and the space phase switching time is determined, and the shortest distances to the left and right from the space motor movement end position to the print start position are determined.

(Operating Principle) In an inkjet printer in which the print cycle is constant and the character size in the horizontal direction changes by changing the speed of the space motor, there is a relationship: space resolution>dot resolution of character size.

Here, space resolution...S□ (space motor) dot resolution 1...pt' (character dot) dot resolution 2...P2 ('') dot resolution 3... ...Pn(''), and these resolutions S□ p,, p2. If the greatest common divisor of p3 is M, then 8 = DanL = Danyu = Yuhong - Jiang -, ---, -(1)S,
1 Pll P2. It becomes P31. S xxrPs1+ Pill P31 is naturally an integer.

Now, if the printing cycle of one dot row is i/T, each dot resolution is P1. P2. The relationship between P and space motor space phase switching time t8 is tn1-TX(S1/P
1) tn2 two TX (S, /P2) ・・・・・・・・・
・・・・・・・・・(2) t , 3:= T X (S
1/P3).

Next, when the printing start position is N, from the space phase switching time t8 of the space motor for each character size,
The printing start delay time t is, however, m1=N MOD S
In the formula, ml represents the remainder of the integer division N/S□□.

This equation (3) becomes the following equation from the above equations (]) and (2).

t 1 '= T X (S, / P,) X
], /S 1i ×m x2TX(17P1□)X
m1 = (T/pxi)xmi Below, formulas (5) and (6) are obtained in the same manner.

T2=(T/P2.)Xm2・・・・・・・・・・・・
・・・・・・・・・・・・(5) t3 ”” (T/P
3s) X m3・・・・・・・・・・・・・・・
・・・・・・・・・(6) The above is the print start delay time t at the dot resolution Px+pz+1)3 for each character size.
ll t2t t3, and the multiplier of each character size at that time is P1□1P211P3□.

Now, if we represent the relationship between equations (4) 2 to (6) in a diagram, it will look like Figure 2. The figure (1) shows the space motor movement direction in the right (forward) direction, and the figure (2) shows the left (reverse) direction.

In figures (1) and (2), S, Xn is the initial space motor phase switching position, S□, X(n-1) is the next space motor phase switching position, and 1s is the next space motor phase switching position. The time to the motor switching position, N indicates the printing start position, and in the case of figure (1), there is a delay of t with respect to S, 1Xn, and figure (
In the case of 2), S is advanced by t with respect to Xn, and t in this case is t=(ts/5xi)x(sx□~(N MOD S,
1))...(7).

As mentioned above, the print start value [
This is characterized in that N is performed at the shortest distance to the left and right by switching the space motor.

Next, an example of the applicant's product will be described.

This printing cycle is an excitation frequency of ink particles of 132 KHz, 1 guard drop (one uncharged particle is interposed between charged ink particles) printing, and when the configuration is 24 vertical dots, the space resolution at this time is 9, and the character size is 9. Po.

The dot resolution of 10.5 points and 12 points is space resolution 1/90 1 (dot resolution 9 points 7/1440 inches → 1/20
5. Finch N 10.5bo 8/1440 inch → 1/180 inch ] 2po 9/1440
inch → 1/160 inch. The greatest common divisor M of these is determined from equation (1) above, so the printing start position N is (
4), (5), (6) Made of wood.

Next, the space phase switching 8 of the space motor The time equation (2) will be described.

In the printing control of the present invention, ink droplet control and space motor control must be synchronized in order to print at the shortest distance to the left and right.

FIG. 5 shows a block diagram of the relationship between the inkjet control section 51 and the main control section 52 of the inkjet printer. The inkjet control unit 51 has a first oscillator 51a,
It consists of a high-precision crystal oscillator and generates the basic clock frequency. This is used to control excitation, charging, distortion correction, etc. of the printer. The main *Jf# section 52 has a second oscillator 52a, which is an inexpensive ceramic oscillator, and its output frequency is used to control the entire printer. Note that an address bus 53. Inkgen l for data bus 54 and main control unit 52
- There are 55 T2 clock lines from the control unit 51, etc.

In the Infusiera 1 to control unit 51, the first oscillator 51a has an excitation frequency of 4.22 MHz±0.01(%) in order to guarantee the ink droplet excitation frequency of 132 kHz±0.01(%).
) crystal oscillator is used. On the other hand, the maximum response frequency of the microcomputer in the main control unit 51 is 12M&, the second oscillator 52a uses an inexpensive ceramic oscillator, and its frequency deviation is at the ±0.5 (%) level. .

As mentioned above, in printing control, it is necessary to synchronize the control of ink particles and the control of the space motor in order to print at the shortest distance to the left and right. Therefore, the space motor control clock is used by correcting the oscillation frequency of the main control section 52 using the basic clock frequency of the inkjet control section 5J.

The correction method is to divide the T2 clock frequency 66KC from the inkjet control unit 51 by 24. The time width of three 330 times is measured using a clock (corresponding to 2 μs) generated by the oscillator of the main control unit 52. Now, the oscillator of the main control unit 52 is
When the count number of 0 pulses (±O (%): 60000) is set, the count number of 330 pulses at ±0.2 (%) is 59880.60120, respectively. Space switching time during printing is 1. ms, +0.2
(%) ”(-22L-59880120m5 x=499 -0.2(%) 21=2260120
．． 120m5 x =501 where 330 counts corresponds to 120m5.

Divide by 24 -120 66KC330 That is, 1 ms when +0.2 (%), -0.2 (%)
The time interval of is 499.5 when counted by the basic clock frequency.
01, and corrects the oscillation frequency of the main control section. This correction is performed during uniform speed printing, and is not performed during non-uniform speed printing such as rising and falling.

The clock frequency of the space motor is determined by the inkjet control oscillation frequency (using a high-precision crystal oscillator) and the oscillation frequency of the main control section (using a low-precision ceramic oscillator).
However, cumulative errors occur due to fractions in correcting the oscillation frequency deviation. For this reason, an error occurs in the phase switching time of the space motor, and the printing start position shifts, resulting in a problem that, for example, vertical ruled lines are not connected.

Therefore, it is necessary to control so that this cumulative error does not occur.

111= Assuming that the number of printing columns is L columns, A. The time required to print the L column is Required time = LXT.

However, T is Todd A. The amount of movement for printing in the L column is Movement amount = L x dot resolution =　L　X　P.

The number of steps in the space motor movement is the number of steps = movement amount / space resolution = L
If n, then n=required time
= (required time Xn/number of steps) - (required time x m/number of steps). This can be summarized as follows.

In this way, the microcomputer in the main control section performs control so that no fraction occurs in the total required time.

(Embodiment) Fig. 1 shows a circuit configuration diagram for input buffer management according to an embodiment of the present invention, which is necessary for controlling the carriage to move to the printing position at the farthest distance to the left or right by inputting print data. The following circuit is shown below. In the figure, 10 is an input column buffer that stores print data from input terminal A, 11 is a microcomputer μCPU that performs overall control of this circuit, etc., and 12
13 is a carriage position counter, and 13 is a print position start determination buffer, which adds the multiplier of each character size until it becomes ``print data available'', and then determines the print position.

14 is a print string counter, and 15 is an image buffer from which print data is output to an output terminal (B). 16
is the space column counter.

Next, to explain the buffer management of this circuit, buffer management is always performed in units of dot rows, and by using the following three modes, if you follow the control example in Table 1, the print data of the print range is stored in the image buffer in Table 2. is transferred and output.

This mode is always used after a modded initial and a line break.

(1) When the contents of the input column buffer 10 are all "O" in the state where print data is input from the input terminal (A), the μCPU II transfers the contents to the image buffer 15.
Controls only the print start position N (see Table 1) without transferring the data to the print position start position N (see Table 1), increases N by an amount corresponding to each dot resolution (the amount of movement for L column printing), and stores each character in the print position start determination buffer 13. Add size multiplier. Nα1 of mode 1 in Table 1.
In the state of No, 2, N moves as O→8→8→16.

The print data in this case is a space sp.

(2) When the contents of the input column buffer 10 are not on, the contents of the input column buffer are transferred to the image buffer 15 by μCPU], l, and the print column counter 14 is set to +
1, the number of columns of print data is counted, and mode 1 is switched to mode 2. Table 1 Mode 1→2 Nα
In state 3, the print data is NOT SP (no space: mark), the print start position N = 16, and No.
In the state of 4, the print string counter 14 is further incremented by 1 and becomes 2.

Mode 2...When there is already some print data in the image buffer 15 (1) When the contents of the input string buffer 10 are all "0",
Transfer the contents of the input column buffer 10 to the image buffer 15
The CPU II does not transfer the print data, and only the space column counter 16 is +1 due to the space SP to count the number of columns of print data with "no space", and switches from mode 2 to mode 3. Nn 5 of mode 2 → 3 in Table 1 In this state, the print string counter 14 remains at 2.

(2) When the contents of the input string buffer lO are not all "0", the same as (2) of mode 1 described above is performed.

Mode 3: Input column buffer 10 is “0” in mode 2
(1) When the contents of the input string buffer 10 are all "0'", it is the same as (1) of mode 2 described above.

(2) When the contents of the input column buffer 11 are not II O++ -15=, the μCPU II transfers the count number 3 of the space column data of the space column counter 16 (state of Nα7 in mode 3 in Table 1) to the image buffer 15. Then, the print string counter 14 is also incremented by +1, making the count number 6. Also, at this time, the count number of the space string counter 16 is made 110'', and then the print data of Nα8 in Table 1 (NOT
SP) is received by the input column buffer 10, and then transferred to the image buffer 16 by μCP Ull, and mote 3 is returned to mote 2.

Buffer management is performed while changing the three modes described above depending on the contents of the input column buffer 10 until printing of one line is completed or until a printing start command is received.

Table 1 (Tears sp...Space NOT SP...Mark period T=1/2750 S1=1/90 P□=1/205.7 P2=1/1
80 P, = 17160M = 1/1440 511 = 1
6 P□□=7P2□=8 P3. =9 Table 2 Print start position N The above control example is a value when the character size is 10.5 points, and the print start position N2=1.6 is as follows.

S□□ n2m madashi n2=1. m2=t2=Q Printing starts at the same time as phase switching position 1 of the Schass motor.

Below, if you print the control example in the same font size of 12 font,
Since the printing start position N3 in Table 1 is the multiplier P3□=9.

N3=18 Sttnlml However, n1=:1. m1=2 t1z(T/P31)×m.

First revision × T × 2 = 80.8 (μs) This is 80.8 (μS) from space motor phase switching point 1
), then printing starts.

When printing in font size 9, the printing start position N in Table 1
□ is P. -7, so N, = 14 Sttn3 m3 However, n, -"O, m3": 14 t3 = (T / P tt) X m3--L
-x-! -x14 = 727.2 (μ3) This is,
Space motor phase switching point 07z7. Printing starts after z (μs).

Next, when controlling printing in both the left and right directions of the carriage,
Due to misalignment between the mechanical part and the electrical control part, the printing positions may not match when printing on the left and right sides.

Figure 3 shows the relationship between the carriage stop position ■ and the positive and negative backlash correction positions ■ and ■, and (1) in the figure shows the carriage position counter (12 in Figure 1) sp po
s indicates the correction position when the amount of backlash is set to X.

Moving the carriage back and forth using the space motor (see figure (2)
)), and at each reversal from backward to forward ((3) in the same figure), SP PO34-5P PO5+ x, SP
PO5←SP PO5-x is corrected by adding to or subtracting from the position counter, and (4) in the same figure shows this state.

Next, in controlling the printing start position when changing the phase of the space motor, since the pitch of the printing start position is in units of 1/1440 according to the above-mentioned example, the phase switching position of the space motor is controlled by 16 etc. Occurs in separated areas.

This is shown in FIG. 4, where d is the phase switching position, e is the printing start position, and n=6.

Next, the carriage is moved to either the left or right direction in accordance with the character size of the input print data, and the shortest distance printing is performed using equation (8).

(Printing start position + printing end position) xi/25 current position・
(8) That is, the difference in distance from the current position of the carriage to points 1z2 is calculated by the μCPU (Fig. 1, 11).
will judge and decide. In this case, as mentioned in Figure 3,
If it is necessary to consider the amount of backlash, (8)
In addition to the formula, decide.

(Printing start position + printing end position + amount of backlash)
i/2〉Current position・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・(9) Also, forward direction (right)
When printing, the amount of backlash is +, and when printing in the opposite direction (left), it is -.

(Effects of the Invention) As described above, the present invention obtains the greatest common divisor of both resolutions from the relationship of space resolution>dot resolution, uses this as a multiplier, and uses a microcomputer to adjust the character size of the input print data. , transfer from input column buffer to image buffer.

The printing data is output after performing the processing necessary for printing, such as determining the printing position, and the carriage moves according to changes in character size.
Since printing is performed at the shortest distance to the left and right from the current position, the printing speed is faster than conventional unidirectional printing. In addition, we have prevented the cumulative error caused by phase switching of the space motor, which is a problem with these operations, and have made corrections to prevent misalignment of the left and right printing positions due to misalignment between the mechanical part and the electrical control part. , even if printing is performed from the wrong position to the left or right, it will be printed at the correct position.

[Brief explanation of drawings]

Fig. 1 is a circuit configuration diagram for input column buffer management according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of space motor phase switching time, and Fig. 3 is an explanation of carriage stop position and positive/negative direction backlash correction. Figure 4 is an explanatory diagram of the space motor phase switching position and printing start position, Figure 5 is a block diagram of the relationship between the inkjet control unit and the main control unit, and Figure 6 is an explanatory diagram of conventional unidirectional printing. It is. 10... Input string buffer, 11... Microcomputer μCPU, 12... Carriage position counter, 13... Print position start determination buffer, 14...
・Print string counter, 15...image buffer,
16... Space row counter, 51... Inkjet control unit, 52... Main control unit, 51a... First oscillator, 52a... Second oscillator. Patent applicant Rico Co., Ltd. Figure 2 Figure 3 ■ ○ ■ 5PPO95PPO9 sPPoS-x
5PPos+×X 1゛1

Claims (3)

[Claims] (1) An inkjet printer is equipped with a first oscillator that generates a fundamental frequency and a second oscillator that performs main control, and when the main control is powered on, the oscillation frequency of the second oscillator is changed to the first oscillator. A frequency control method for an inkjet printer, characterized in that the frequency is corrected using the frequency of an oscillator. (2) Claim (1) characterized in that the space phase switching time during constant speed printing is performed at a corrected time.
Frequency control method for inkjet printers described in Section 1. (3) When printing the L column, calculate the time required to print the L column using the corrected time, and calculate this from the nth to the number of space motor steps calculated from the space resolution and movement amount of the space motor. Phase switching time up to the m-th time t_n = required printing time x n / number of steps t_m = required printing time x m / number of steps is determined, and t_n - t_m is set as the phase switching time of the space motor. Scope paragraph (1);
The frequency control method for an inkjet printer according to any one of item (2).