JP2002210930A - Method of controlling printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of controlling the printing capable of achieving high resolution by suppressing a control frequency of a motor for conveying a paper. SOLUTION: A minimum paper conveyance pitch P is set to satisfy the formula: P= N+(1/M)}×K with the proviso that K represents a nozzle pitch in an ink head, N represents an integer of not less than 1 and M represents an integer of not less than 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a print control method for an ink jet printer.

[0002]

2. Description of the Related Art Conventionally, in an ink jet printer, a resolution in a paper feeding direction is, for example, 1200 dpi.
(Dot per inch), the minimum resolution of the feed motor was set to 1/1200 dpi.
In other words, in the case of pulse motors that are commonly used,
One-step paper feed is mechanically associated with 1/1200 dpi.

Accordingly, as the resolution increases, the control frequency of the motor increases, and the control load of the MPU (microprocessor unit) and the like increases. To avoid this, the paper feed speed is reduced (the printing speed is reduced). Lowering). This method reduces the printing speed of the printing mechanism and is not a preferred method.

For example, at a high resolution of 1200 dpi, 20
When performing high-speed paper feed of ips (inch per second), 24000 steps / sec.
(= 1200 steps / inch × 20 ips), that is, motor rotation control of 24000 steps per second was required. Therefore, the control frequency (= 24 KHz) is high, and the load on the control device increases.

Incidentally, the number of nozzles of the ink head 8 shown in FIG. 7 is 320, the nozzle interval is 0.0423 mm, and the print width (paper feed amount) at one time is 13.494 mm (319 ×).
0.0423 mm), and as shown in FIG.
When paper is fed at the nozzle pitch (（of the nozzle interval), the paper feed pitch (paper feed width) is (120).
0 dpi ≒) 0.02115 mm.

[0006]

As described above, in order to obtain a printing resolution higher than the nozzle arrangement resolution for high image quality, the paper feed pitch must be reduced in the conventional printing method. When a high-speed printing paper feed is performed with the paper feed pitch set small, the control frequency increases and the load on the CPU that controls the paper feed motor increases.
In addition, there has been a problem that the noise of the motor increases with an increase in the frequency.

The present invention has been made in view of such circumstances, and has as its object to provide a print control method capable of realizing high resolution and low noise by suppressing the number of revolutions of a paper feed motor.

[0008]

According to the present invention, means for solving the above-mentioned problems are constituted as follows.

(1) The nozzle pitch of the ink head is K,
When the integer of 1 or more is N, and the integer of 2 or more is M, the minimum paper feed pitch P is set to satisfy the following equation: P = {N + (1 / M)} × K Features.

According to this method, for the fractional part (fractional part), for example, when M is 2, that is, for example, the minimum paper feed pitch P is set to 2 (1/2), 3 (1 /
2), 4 (1/2) ..., 600 dpi 2
This enables printing at 1200 dpi, which is twice as large. 2 (1 /
When 3), 3 (1/3), 4 (1/3),... Are set, the resolution is tripled.
00 dpi can be printed. 2 (1/5), 3 (1
/ 5), 4 (1/5),..., The resolution is five times, and printing at 3000 dpi, which is five times 600 dpi, is possible.

As described above, if the fractional part (fractional part) of the equation is set to (1 / M), a head having a nozzle pitch of 600 dpi is used, and the paper feed resolution is set abnormally finely. No, 600 × Mdpi
(M times) resolution can be obtained.

(2) Of the nozzles of the ink head,
The first to N-th nozzles are characterized in that ink is not ejected at the beginning of printing of each page.

At the beginning of printing, the print start position at the head of the paper is Nth
By preventing ink from being ejected from the first to Nth nozzles until the stage corresponding to the first nozzle, it is possible to prevent a desired resolution from being obtained in the first line (from the first line). The desired resolution can be obtained).

For example, as shown in FIG. 3, when the minimum paper feed pitch P is set to 2.5 nozzle pitch, the minimum paper feed pitch is set to 2.5 nozzle pitch at the head of the printing paper. Between the first nozzle (n1) and the third nozzle (n3), the desired resolution (2
2) cannot be obtained, it is sufficient to start printing from nozzle n3 without discharging ink from the two nozzles n1 and n2. After that, both nozzles n1
And ink may be ejected from n2.

(3) Of the nozzles of the ink head,
The paper is conveyed so that the (N + 1) th nozzle corresponds to the first print position of each page.

At the time when the first print position reaches the (N + 1) th nozzle, if ink is ejected from that nozzle,
Printing can be started at a desired resolution from the first line.

For example, as shown in FIG. 3, when the minimum paper feed pitch P is set to 2.5 nozzle pitch, when the print start position of the head of the paper reaches the (N + 1) th nozzle n3, thereafter, Since a desired resolution (twice) can be obtained, printing can be started at a desired resolution from the top row by discharging ink from the nozzle n3.

(4) Nozzles that do not discharge ink at the beginning of printing of each page are set corresponding to each minimum paper feed pitch P.

At the top of the paper where the desired resolution cannot be obtained, the desired resolution can be ensured by preventing ink from being ejected from the predetermined nozzles.

For example, as shown in FIG. 3, when the minimum paper feed pitch P is set to 2.5 nozzle pitch, at the stage where the paper is initially fed and moved by 2.5 nozzle pitch, the nozzles n1, By not discharging ink from n2, a desired resolution can be obtained from the first row.

(5) There is a nozzle which does not discharge ink corresponding to each minimum paper feed pitch P, and the number of nozzles is different depending on each minimum paper feed pitch P.

In the leading portion of the paper where the desired resolution cannot be obtained, the desired resolution can be ensured by preventing ink from being ejected from predetermined nozzles. The predetermined number of nozzles may be set according to each paper moving distance.

For example, as shown in FIG. 3, when the minimum paper feed pitch P is set to 2.5 nozzle pitch, initially, the paper movement distance until the paper is fed by 2.5 nozzle pitch is moved. By not discharging ink from the nozzles n1 and n2, a desired resolution can be obtained from the first row. After that, the ink may be ejected also from the nozzles n1 and n2.

(6) The number of nozzles is H, which is L times the minimum paper feed pitch P (L is an integer) and the product (P × L) of both is also an integer.

By setting the number of nozzles so as to satisfy the above condition, it is possible to prevent ink dots from being overprinted and to use nozzles efficiently.

For example, as shown in FIG. 4, when the minimum paper feed pitch P is set to 3.5 nozzle pitch, the nozzle n
Regarding 316 to n320, overlapping ejection of ink can be avoided by always not discharging ink. In this case, P is 3.5, L is 90, and K is 3
There are 15 settings.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printing control method according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the main structure of an ink jet printer, in which a sheet 1 is placed on a sheet feed tray 2 and
When a printing request based on image information output from a computer or the like (not shown) is made to the apparatus, one of the sheets is fed and conveyed by the pickup roller 3, and the sheet 1 is
The paper feed path 4 is passed by the paper feed roller 4, and the printing unit 7 is further fed by the PS paper feed roller 6 that adjusts the front end of the image information and the front end position of the paper 1 based on the image information.
To reach.

The printing unit 7 includes an ink carriage 10 having an ink head 8 and an ink tank 9, and ink carriage holding shafts 11, 11 and the like provided to smoothly guide the ink carriage 10. ,
The required ink is ejected from the ink head 8 in accordance with the image information, and the image information is formed and reproduced on the paper 1.

During printing, the paper 1 is temporarily stopped, and when one line of printing scanning (scanning in the direction perpendicular to the paper surface of FIG. 1) is completed by the ink carriage 10, the paper 1 is moved by a predetermined paper feeding amount. Is fed and the next one line is printed.

As described above, the printing process for reproducing the image information is continuously performed in the printing unit 7, so that the image information is written on the paper 1 by the ink. The paper 1 on which the image is formed is discharged to a paper discharge tray 13 by a paper discharge roller 12 and provided to a user as a printed matter.

In such an ink jet type printer, in the present embodiment, in order to realize a high resolution by suppressing the number of rotations of a motor (not shown) for moving the printing paper 1, the minimum paper feed pitch P Is set as follows. That is, when the pitch of the nozzles arranged on the lower surface of the ink head 8 is K, the integer of 1 or more is N, and the integer of 2 or more is M, the minimum paper feed pitch P is P = ｛N + (1 / M) ｝ × K... Are set to satisfy the above expression. In this embodiment, the ink head 8 has a nozzle number 320 shown in FIG.
Shall be used.

As described above, by setting the minimum paper feed pitch P, if the fractional part (fractional part) of the equation is set to (1 / M), the resolution can be improved to M times. In addition, the step frequency of the motor for moving the printing paper 1 can be reduced to 1 / (P × M), so that the generation of noise can be suppressed and the control load of an MPU (microprocessor unit) and the like can be suppressed low. .

FIG. 2 is an explanatory diagram comparing the print control method of the present embodiment with the prior art. The minimum paper feed pitch (or the minimum paper feed pitch) P is changed to 2.5 nozzle pitch (motor control 1).
Pulse), that is, in the equation, N =
When 2, M = 2, and K = 600 dpi (the ink jet head 8 shown in FIG. 7), as can be confirmed from the print result on the right side, a resolution of 1200 dpi (double the conventional resolution) is obtained from nozzle n3 onward. At the beginning of the paper feeding before that, there is no nozzle corresponding to the line shown by the broken line, and a desired resolution (1200 dpi) cannot be obtained.

Therefore, the first nozzle n1 and the first nozzle n2
Does not discharge ink at the initial stage of paper feeding, but discharges ink from the nozzle n3. In the right print result, a broken line above the print indicates a line where ink is not discharged (is not dischargeable).

The printing control method according to the present embodiment in which the minimum paper feed pitch P is set to 2.5 nozzle pitches,
When performing high-speed printing (high-speed paper feed) of 20 ips at 0 dpi (under the same conditions), the control frequency is compared with the prior art, and as shown in the lower part of FIG. Becomes 5 times, and the control frequency becomes 1/5.

As described above, when high-speed printing is performed with the same resolution, the control frequency of the print paper transport motor can be reduced to 1/5 in the method of the present embodiment as compared with the conventional method. Therefore, the generation of noise can be significantly suppressed, and the control load on the MPU can be significantly reduced.

FIG. 3 shows details of nozzle movement when the minimum paper feed pitch P is set to 2.5 nozzle pitches. In this case, all 320 nozzles of the ink head 8 are used. Thus, initially, the first nozzle n1 and the second nozzle n2 do not discharge ink, and start discharging ink from the third nozzle n3. This is until the paper is initially fed by 2.5 nozzles.
Thereafter, ink is also ejected from both nozzles n1 and n2. In this case, a paper feed pitch five times (= 2.5 / 0.5) is obtained with respect to the conventional 0.5 nozzle pitch, and the control frequency is ５ of 4.8 kHz.

FIG. 4 shows the case where the minimum paper feed pitch P is set to 3.5 nozzle pitch, that is, N = 3,
The details of the nozzle movement when M = 2 and K = 600 dpi (the inkjet head 8 shown in FIG. 7) are shown.
In this case, 315 nozzles of the ink head 8 are used,
At the paper moving distance of 3.5 nozzle pitch and the 311.5 nozzle pitch, the nozzles n316 to 320 are not ejected with ink, and at the head of the paper, the ink is not ejected from the nozzles n1 to n3, and the fourth nozzle n4 is not ejected. , And thereafter, the ink is also ejected from the nozzles n1 to n3. Also in this case, 7 times (= 3.5 / 0.
The paper feed pitch of 5) is obtained, and the control frequency is 1/3, 3.43 kHz.

FIG. 5 shows a case where the minimum paper feed pitch P is set to 7.5 nozzle pitches, that is, N = 7,
The details of the nozzle movement when M = 2 and K = 600 dpi (the inkjet head 8 shown in FIG. 7) are shown.
In this case, the nozzle 315 of the ink head 8 (P is 7.
5, L is 42), and at the paper movement distance of 7.5 nozzle pitch and 307.5 nozzle pitch, nozzle n3
No ink is ejected from Nos. 16 to 320, and ink is not ejected from nozzles n1 to n7 at the head of the sheet.
The discharge of the ink is started from the nozzle n8, and thereafter, the ink is also discharged from the nozzles n1 to n7. Also in this case, a paper feed pitch 14 times (= 7.5 / 0.5) is obtained with respect to the conventional 0.5 nozzle pitch, and the control frequency is 1/14, which is 1.7 kHz.

FIG. 6 shows the paper feed nozzle pitch (minimum paper feed pitch P) and the number of nozzles used.
Each numerical value is divisible by the minimum paper feed pitch P. In each of the above embodiments, the value of M in the equation is 2
And the resolution was set to 1200 dpi.
It is needless to say that a desired high resolution can be obtained by appropriately selecting the value of.

According to the printing control method of this embodiment, as described above, the control program set and stored in advance is used without particularly changing the configuration of the ink head 8 itself and without adding another member. The number of nozzles to be used (discharges ink) is set individually according to the minimum paper feed pitch P selected at that time, and ink is not discharged from a specific nozzle at the head of the printing paper.
The rear end of the nozzle can be realized by controlling and driving the ink head 8 so that the required nozzle is not used depending on the value of the minimum paper feed pitch P to be used. , Noise generation can be suppressed, the control load on the MPU can be kept low, and high resolution can be ensured.

[0043]

As can be seen from the above description, the present invention has the following effects.

According to the first aspect, the value of the minimum paper feed pitch P is appropriately selected and set according to the printing condition according to the equation, so that the fractional part (fractional part) of the equation is (1).
/ M), the resolution can be improved by a factor of M, the frequency of the motor driving the ink head can be reduced to 1 / (P × M), and the generation of noise can be suppressed. , MPU, etc., the control load can be significantly reduced.

According to the second aspect, by preventing ink from being ejected from the first to Nth nozzles at the beginning of printing, it is possible to prevent a desired resolution from being obtained in the first row. For example, if the minimum paper feed pitch P is 2.
When the nozzle pitch is set to 5 nozzles, ink is ejected from the two nozzles n1 and n2 until the head of the paper corresponds to the first nozzle (n1) and the second nozzle (n2). Instead, printing may be started from the nozzle n3. After that, both nozzles n
It is only necessary to eject ink from 1 and n2.

According to the third aspect, when the head of the sheet reaches the (N + 1) th nozzle, ink can be ejected from that nozzle, so that printing can be started at a desired resolution from the top line. For example, if the minimum paper feed pitch P is 2.5
When the nozzle pitch is set, when the head of the sheet reaches the (N + 1) th nozzle n3, the nozzle n
If ink is ejected from No. 3, printing can be started at a desired resolution from the first line.

According to the fourth aspect, at a paper moving distance at which a desired resolution cannot be obtained, printing can be performed at a desired resolution by preventing ink from being ejected from predetermined nozzles. For example, if the minimum paper feed pitch P is 2.5
When the nozzle pitch is set, at the top of the printing paper,
By not discharging ink from the nozzles n1 and n2, a desired resolution can be obtained from the first row.

According to the fifth aspect, printing can be performed at a desired resolution by preventing ink from being ejected from predetermined nozzles at the leading portion of the printing paper where the desired resolution cannot be obtained. The predetermined number of nozzles may be set according to each paper moving distance. For example, if the minimum paper feed pitch P is set to 2.5 nozzle pitch,
At a sheet moving distance until the sheet is fed and moved by 2.5 nozzle pitches, a desired resolution can be obtained from the top row by not discharging ink from the nozzles n1 and n2. Then, in the subsequent stage, the nozzle n
Ink may be ejected also from 1 and n2.

According to the sixth aspect, by setting an unused nozzle at the rear end of the nozzle in accordance with the setting of the minimum paper feed pitch P, it is possible to avoid overlapping of ink. For example, when the minimum paper feed pitch P is set to 3.5 nozzle pitch, the nozzles n316 to n320 are prevented from ejecting ink irrespective of the paper movement distance, thereby avoiding overlapping ink ejection. it can.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory diagram showing a main configuration of an ink jet printer to which a print control method of the present invention is applied.

FIG. 2 is an explanatory diagram in which the print control method of the present invention is compared with a conventional technique.

FIG. 3 is an explanatory diagram showing details of nozzle movement when the minimum paper feed pitch is set to 2.5 nozzle pitch.

FIG. 4 is an explanatory diagram showing details of nozzle movement when the minimum paper feed pitch is set to 3.5 nozzle pitch.

FIG. 5 is an explanatory diagram showing details of nozzle movement when the minimum paper feed pitch is set to 7.5 nozzle pitch.

FIG. 6 is a table showing the number of used nozzles corresponding to the paper feed nozzle pitch (minimum paper feed pitch).

FIG. 7 is an explanatory diagram showing an arrangement of nozzles of a conventional ink head.

FIG. 8 is an explanatory diagram showing nozzle print positions (lines) when the minimum paper feed pitch is set to 0.5 nozzle pitch.

[Explanation of symbols]

 1-Ink head K-Nozzle pitch N-1 or more M-2 or more P-Minimum paper feed pitch L-Integer H-Number of nozzles

Claims (6)

[Claims] When the nozzle pitch of the ink head is K, the integer of 1 or more is N, and the integer of 2 or more is M, the minimum paper feed pitch P is expressed by the following equation: P = {N + (1 / M)} × K .... A printing control method characterized by being set so as to satisfy the following. 2. The method according to claim 1, wherein the first of the nozzles of the ink head is a first one.
2. The print control method according to claim 1, wherein ink is not ejected at the beginning of printing of each page for the nozzles from the Nth to the Nth. 3. The method according to claim 1, wherein the nozzle of the ink head includes an N-th nozzle.
2. The print control method according to claim 1, wherein the + 1st nozzle carries the paper so as to correspond to the first print position of each page. 4. The printing control method according to claim 1, wherein nozzles that do not discharge ink at the beginning of printing of each page are set corresponding to each of the minimum paper feed pitches P. 5. The printing method according to claim 1, further comprising a nozzle that does not eject ink corresponding to each of the minimum paper feed pitches P, and the number of nozzles varies with each of the minimum paper feed pitches P. Control method. 6. L times the minimum paper feed pitch P (L is an integer)
2. The print control method according to claim 1, wherein the number (H) of nozzles for which the product (P × L) of the two is also an integer is used.