JPH07266551A - Ink jet type image forming device - Google Patents

Abstract

PURPOSE:To prevent bleeding from occurring even when ink of which drying speed is small is used by a method wherein printing is alternately carried out on a line a plurality of lines apart from the line printed just before and on a line directly near the line printed before the last time. CONSTITUTION:For example, in the case of a recording head of M numerical aperture of 16 nozzles at 4 dots pitch, a printing line pitch is taken as P. Firstly after completion of printing L1 and L5, paper is fed in a regular direction by 2,XP, 2 line content, and L3 and L7 are printed. Paper is fed in the regular direction by 1XP, 1 line content, and L4 and L8 are printed. Then, paper is fed in a reverse direction by 2XP, 2 line content. After completion of printing L2 and L6, paper is fed in the regular direction by 4 1 line content, i.e., [4 (M-1)+3] P content. Then, L9, and L13 are printed, and paper is fed in the regular direction by 3XP, 3 line content. L12 and L16 are printed, and paper is fed in the reverse direction by 2XP, 2 line content. L10 and L14 are printed, and paper is fed in the regular direction by 1XP, line content. After printing L11 and L15, paper is fed by [4(M-1)+2] P content, and printing is carried out on an area not to be printed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet image forming apparatus for printing characters and images by reciprocating an ink jet recording head having a plurality of nozzle openings in the paper feeding direction in the paper width direction.

[0002]

2. Description of the Related Art In the case of printing graphic data using an inkjet recording head, a plurality of recording heads having different ink colors are used in preparation for color printing. As described above, N nozzle openings are arranged at a K dot pitch, and
A method is adopted in which the K and N are relatively prime to each other and the recording paper is fed at a constant pitch N relationship. According to this, although the feeding control of the recording paper and the extraction of the print data become uniform, the data processing can be simplified, but
Since the pitch of nozzle openings and the number of nozzle openings must be set to be relatively prime, not only is there a restriction on the print heads that can be used, but it is also possible that the ink image formed by the previous scan is adjacent. Since the next ink image is then formed, there is a problem that bleeding may occur when ink having a low drying speed is used.

Further, since the positions of the recording head and the recording paper in the paper feed direction are constantly changed at the same pitch, when there is an error in the arrangement of the plurality of nozzle openings of the recording head, the stripes of light and shade are periodically generated. However, there is a problem in that the print quality tends to be conspicuous and the print quality deteriorates.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and actively takes advantage of the speeding up of data processing due to the recent rapid development of microcomputers. To provide a novel ink jet image forming apparatus capable of simplifying printing, suppressing the occurrence of ink bleeding as much as possible, and softening the lightness and darkness due to the arrangement error of the nozzle openings to improve the printing quality. With the goal.

[0005]

In order to solve such a problem, the present invention reciprocates in the width direction of the recording medium, and also has a pitch K = 4 × P in the paper feed direction (P is a print line). M nozzle openings arranged in a pitch)
A recording head having nozzle openings of 2 or more),
Paper feeding means for moving the recording medium in the paper feeding direction orthogonal to the movement direction of the recording head in units of pitch P;
2xP, 1xP forward paper feed, then 2xP
Printing is performed while performing paper feeding in the reverse direction of [1], and then paper feeding in the forward direction of [4 (M-1) +3] P is performed.
Printing is performed while executing the process, the paper feed in the forward direction of 3 × P, the paper feed in the reverse direction of 2 × P, and the paper feed in the forward direction of 1 × P, and then [4 (M -1) +2] and a control means for alternately executing the second printing step of feeding the paper in the forward direction.

[0006]

Operation: A line separated from a line printed immediately before or a line immediately before the line printed before the previous time is printed on the line to prevent color mixture with ink due to the previous printing. Further, the first and second printing steps are alternately repeated to change the positions of the lines in which the same nozzle openings are adjacent to each other and to print, to disperse the lines caused by the error in the nozzle opening arrangement pitch.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 is a recording head.
As shown in (a) and (b), 16 nozzle openings 2, 2, 2 are arranged at a predetermined pitch, in this embodiment, a 4-dot pitch.
..., and 16 nozzle openings 2 with a 6-dot pitch,
.. are formed in one line in the paper feed direction, mounted on the carriage 3 and reciprocally provided in the axial direction of the platen 4.

The carriage 3 is reciprocally attached to a guide member 5 provided parallel to the axial direction of the platen 4 and is driven by a pulse motor 7 connected via a timing belt 6.

A paper feed motor 8 is connected to the platen 4 via a transmission mechanism in this embodiment, and is a motor capable of forward and reverse rotation so as to feed and pull back the recording paper with an accuracy of 1 dot unit. ing.

Reference numeral 16 denotes a data extraction unit, which prints the print data sent from the host (not shown) and stored in the reception buffer 13 from the bitmap data expanded in the image memory 15 by the expansion unit 14 and performs print control described later. Means 1
The data is extracted every four lines based on the command of No. 8 and is output to the head drive circuit 17.

Reference numeral 18 denotes the above-mentioned print control means, so as to realize the printing process described later, the paper feed amount after the end of each one pass,
Alternatively, the paper feed control means 20 and the data extraction means based on the data concerning the amount of pullback of the bite and the data of the control data storage means 19 storing the address of the bit map of the line where the nozzle opening is located by these paper feed and pullback amounts. 16 is configured to be controlled.

That is, assuming that the pitch of the printing line is P and the number of nozzle openings is M, 2 × P, 1 × P forward paper feed, and then 2 × P backward paper feed. Then, [4 (M-1) +3] P forward paper feed 1 step, 3 × P forward paper feed, 2 × P reverse paper feed, 1 × P Paper feed data for executing the paper feed to the forward direction of [4 (M-1) +2] alternately and the paper feed data for alternately executing the paper feed process to the forward direction of [4 (M-1) +2] The line data can be extracted.

Next, the operation of the apparatus thus constructed will be described with reference to FIG. 3 by focusing on two of the nozzle openings. When input to the reception buffer 13 from a host (not shown), it is expanded into bitmap data by the expansion means 14 and stored in the image memory 15. Data extraction means 1
Reference numeral 6 extracts the data of the area designated by the image print control unit 18, that is, the first line and the fifth line.
When the preparation of the data to be printed is completed in this way, the motor 7 is driven and the recording head 1 moves in the main scanning direction of the recording paper. As a result, the recording head 1 forms dots every four dots in the sub-scanning direction while moving one dot at a time in the main scanning direction, and executes printing of the lines L1 and L5 (1-1 of the first step).

When the printing of the lines L1 and L5 is completed in this way, the print control means 18 drives the paper feed motor 8 based on the data stored in the control data storage means 19 to print the recording paper 2 The line is advanced, and the nozzle openings 2 and 2 of the recording head 1 are moved to the planned printing line L of the recording paper.
3, facing L7.

At the same time, the data extraction means 16 extracts the bitmap data of the lines L3 and L7 offset by two lines from the bitmap data developed in the image memory 16 and outputs it to the recording head drive circuit 17. Ink droplets are ejected from the nozzle openings 2 and 2 in accordance with the movement of the carriage 3 that moves according to the print timing signal, and dots are formed on the recording paper.

By the way, the line L to be printed now
Since 3 and L7 are both separated from the previously printed lines L1 and L5 by 2 lines, there is no dot printed immediately before in the vertically adjacent lines, and therefore, even if the ink has a slow solvent drying speed, Even if there is, bleeding does not occur (1-2 of the first step).

Next, the paper feed for one line is executed to make the nozzle openings 2 and 2 face the lines L4 and L8, and the print data of the lines L4 and L8 are output to the recording head 1 to execute the printing. (1-3 of the first step).

Next, the recording paper is pulled back by two lines, and the lines L2 and L6 are printed in a state where the lines L2 and L6 are nozzle openings (first step 1-4).

In this way, when all printing between the nozzle openings is completed, the print control means 18 sets the recording paper to 7
Paper is fed by the line, that is, the nozzle numerical aperture M × dot pitch-1 minute.

As a result, the nozzle opening 2 at the upper end of the recording head 1 is located on the line L9 next to the final line L8 on which printing has been completed in the first step. In this state,
Printing is executed (2-1 of the second step). The line L8 located immediately above the line L9 to be printed now is
Previously, the ink was printed the last time, the ink is sufficiently dry,
Further, since the line L10 located immediately below is the unprinted area, the ink solvent does not cause bleeding.

Next, the print control means 18 sets the recording paper to 3
The paper is fed by the line and the nozzle openings 2 and 2 are opposed to the lines L12 and L16 to enable printing of the lines L12 and 16 (2-2 of the second step). Of course, the line L11 located immediately above the lines L12 and L16 to be printed is an unprinted area, and the line L13 located immediately below the line L13 has been printed last time.
Since it is dry due to the relatively large feed time of 3 lines, printing can be performed without causing ink bleeding.

Next, the print control means 18 drives the motor 8 in the reverse direction to pull back the recording paper by two lines, and the nozzle openings 2 and 2 of the recording head 1 are moved to the planned printing line L1 of the recording paper.
0 and the line L14 are opposed to each other, and data corresponding to these lines are output to the recording head 1 to print these lines (second step 2-3). Even in this case, the most recent upper lines L9 and 13 are printed in the previous time, and the lower lines L11 and 15 are unprinted regions.
It does not cause ink bleeding.

Further, the paper is fed by one line so that the nozzle openings face the lines L11 and L15 and printing is performed (2-4 of the second step).

When the second printing process is completed in this way, the print control means 18 feeds the recording paper by the line and prints the nozzle opening at the upper end of the recording head 1 on the line L17 at the upper end of the unprinted area. Then, the printing is continued by the above-mentioned first step. Thereafter, one page is printed by alternately repeating the first and second printing steps in this manner.

FIG. 4 shows a second embodiment of the present invention using a recording head (FIG. 6B) in which nozzle openings 2, 2, 2, ... Are arranged at a pitch of 6 dots. It is the figure which paid its attention to the opening and was demonstrated.

In this case, the control data storage means 19 described above stores the pitch of the print lines as P and the number of nozzle openings as N.
Then, 2 × P, 2 × P forward paper feed, and 3 ×
Paper feeding process for performing paper feeding in the reverse direction of P, paper feeding in the forward direction of 2 × P, 2 × P, and paper feeding in the forward direction of [6 (N−1) +1] × P , 2 × P, 3 × P forward paper feed, 4 × P reverse paper feed, 2 × P, 1
XP forward paper feed and [6 (N-1) +2] xP
And data for executing the paper feeding step of feeding paper in the forward direction, and control data for extracting the bit map data at the position where the nozzle openings face each other by the paper feeding.

Two lines L separated by 6 lines
When the printing of Nos. 1 and 7 is completed (1-1 of the first step), the printing control unit 18 feeds the recording paper by two lines, and the nozzle openings 2 and 2 are separated from the first printing line by two lines. The lines L3 and L9 are opposed to each other. When printing is performed in this state, the upper lines L2 and L8 immediately below the lines L3 and L9 to be printed now and the lower lines L4 and L1 are printed.
Since 0 is an unprinted area, printing is performed without causing ink bleeding (first step 1-2).

The recording paper is further fed by two lines so that the lines L5 and 11 are opposed to the nozzle openings, and again the nearest upper lines L4 and L10 and lower lines L6 and L12 are both unprinted. It is printed at the location of the area (1-3 in the first step).

Then, the print control means 18 pulls back the recording paper by three lines and prints the first printed lines L1 and L.
7 and the previous line L that was printed last time and is sufficiently dry
Nozzle opening is located between 3 and L9 (1 in the first step)
-4).

Then, the paper is fed by two lines, and the lines L3 and L9, which are printed before the previous time and the ink is sufficiently dried, and the lines L4 and L10 between the lines L5 and L11, are printed. (1st step 1-
5).

Similarly, the paper is fed by two lines, and the lines L6 and L12 located between the lines L5 and L11 and the lines L6 and L12 where the printing is performed before the previous time and the ink is sufficiently dried. Is printed (1-6).

When the first printing process is completed in this way, the paper feed control means feeds the recording paper by the line, and the nozzles at the upper end of the recording head make the line L1 at the upper end of the unprinted area.
Line L1 located at No. 3 and having nozzle openings facing each other
3 and L19 can be printed (2-1).

By the way, the line L1 to be printed now
The line L12 printed immediately before is present on the upper side of the line 3, but since a large amount of paper has been fed after the printing of this line L12 and time has elapsed until printing, this line L1
When printing of No. 3 is executed, the ink is sufficiently dried and ink bleeding does not occur.

When the printing of the lines L13 and L19 is completed, the paper feed for two lines is performed, and the line L15, which is located between the unprinted lines on the immediate upper side and the lower side,
The process moves to L21 to execute printing (2-2).

Next, the recording paper is fed by three lines, the nozzle openings are made to face the lines L18 and L24, and these lines are printed (2-3). Of course, the lines L17 and L23 located on the immediate upper side of these lines L18 and L24 are unprinted areas, and the line L19 located on the lower side is printed before the previous time and the ink is sufficiently dried. No ink bleeding occurs.

Then, the paper feed control means sets the recording paper to 4
Lines are pulled back, and lines L13 and L20 and lines 14 and L2 that have been printed before the previous time and have dried sufficiently
The lines L14 and L20 between 1 are opposed to the nozzle openings (2-5).

When the printing of the lines L14 and L20 is completed, the paper is fed by one line and the lines L17 and L20 are fed.
23 is printed (2-6).

When the printing of the final line is completed in this way, the print control means 18 feeds the recording paper by * lines, and the line L25 at the upper end of the unprinted area is moved to the nozzle opening at the upper end of the recording head. Position and return to the first step described above to print the remaining data. Thereafter, one page is printed by alternately repeating the first and second printing steps in this manner.

According to this embodiment, since the nozzle pitch is large, the degree of freedom in selecting the line to be printed is high, the line printed immediately before can be avoided as much as possible, and the blurring can be further enhanced. Printing with less printing becomes possible.

In the above-mentioned embodiment, for simplification of description, the recording head in which a plurality of nozzle openings are provided in one row is taken as an example, but a plurality of nozzle openings are arranged in each of the plurality of rows. In addition, it is clear that the same effect can be obtained even if each row is provided on the same base or carriage with a constant pitch and is used for a color printer that ejects different inks for each row.

Further, in the above-described embodiment, the case where the cut sheet is used has been described as an example, but it is obvious that the present invention can be applied to the printer using the continuous sheet.

[0042]

As described above, in the present invention, M nozzle openings reciprocating in the width direction of the recording medium and arranged at a pitch K = 4 × P in the paper feeding direction (M is 2). A recording head having a nozzle opening of the above integer), a paper feeding unit for moving the recording medium in the paper feeding direction orthogonal to the moving direction of the recording head in units of the pitch P of the print line, 2 × P, 1 × Paper feed in the forward direction of P and paper feed in the backward direction of 2 × P are executed, and then (M
+3) a first printing step for feeding paper in the forward direction of P,
Ink is ejected while performing paper feeding in the forward direction of 3 × P, paper feeding in the reverse direction of 2 × P, and paper feeding in the forward direction of 1 × P, and then (M + 2) × P Since the control means for alternately executing the second printing step for feeding the paper in the forward direction is provided, the printing on the line adjacent to the line printed immediately before is reduced as much as possible to prevent bleeding. Not only can this be prevented, but the order of the print lines can be changed to disperse the error in the arrangement pitch of the nozzle openings to disperse the streaks due to the arrangement error of the nozzle openings. Can be increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an apparatus showing an embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing a nozzle array of an ink jet recording head used in the above apparatus, respectively.

FIG. 3 is an explanatory diagram showing an operation of the same apparatus.

FIG. 4 is a diagram showing another embodiment of the present invention in a printing process.

[Explanation of symbols]

 1 Recording head 2 Nozzle opening 3 Carriage 4 Platen 7 Pulse motor 8 Pulse motor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B41J 19/00 A B41J 3/10 101 E

Claims (2)

[Claims] 1. M number of nozzle openings (M is an integer of 2 or more) which reciprocates in the width direction of a recording medium and is arranged in a paper feed direction at a pitch K = 4 × P (P is a pitch of a print line). ) A recording head having a nozzle opening, a paper feeding means for moving the recording medium in a paper feeding direction orthogonal to the moving direction of the recording head in units of pitch P, and 2 × P, 1 × P forward direction Paper feed and then 2 x P
Printing is performed while performing paper feeding in the reverse direction of [1], and then paper feeding in the forward direction of [4 (M-1) +3] P is performed.
Printing is performed while executing the process, the paper feed in the forward direction of 3 × P, the paper feed in the reverse direction of 2 × P, and the paper feed in the forward direction of 1 × P, and then [4 (M −1) +2], and an inkjet image forming apparatus including a control unit that alternately executes the second printing process of feeding the paper in the forward direction. 2. A reciprocating movement in the width direction of the recording medium, and N nozzle openings (N is an integer of 2 or more) arranged in the paper feeding direction at a pitch L = 6 × P. A recording head; a paper feeding means for moving the recording medium in the paper feeding direction orthogonal to the moving direction of the recording head in units of the pitch P of the print line; and a paper feeding in the forward direction of 2 × P, 2 × P. Printing is performed while performing paper feeding in the reverse direction of 3 × P and paper feeding in the forward direction of 2 × P and 2 × P, and then [6 (N−1) +1] ×
The first printing step of feeding the paper in the forward direction of P, 2 × P,
Printing is performed while performing paper feeding in the forward direction of 3 × P, paper feeding in the reverse direction of 4 × P, and paper feeding in the forward direction of 2 × P, 1 × P, and then [6 ( N-1) +2] × P An inkjet image forming apparatus including: a control unit that alternately executes a second printing step of feeding the paper in the forward direction.