JPH11235834A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus that does not suffer from no hue difference between bi-directional recording and forward recording, and enable user to print recording in accordance with the purpose of use in bi- directional recording and forward recording. SOLUTION: Cyan has dots disposed at a pitch of 360 DPI at the half of printing resolution 720 DPI. On the other hand, magenta has dots disposed at a pitch of 180 DPI, viz., a quater of the printing resolution 720 DPI in a position shifted in printing head direction only by 720 DPI relative to cyan dots. Yellow has dots disposed like magenta. Namely, yellow has dots disposed at a pitch of 180 DPI, viz., a quater of printing resolution of 720 DPI in a position shifted in the printing head moving direction only by 360 DPI relative to dots of magenta. When scanning is completed, a recording medium transportation control circuit operates to drive a motor so as to permit the recording medium only at a predetermined rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, an electromechanical transducer is connected to a pressure chamber filled with ink, and a pressure is generated in the pressure chamber by applying an electric signal to cause an ink droplet to be ejected from a nozzle. , Characters and images. In such an ink jet recording apparatus, there is a bidirectional recording method in which a print head is reciprocated in a width direction of a recording medium to perform recording in order to improve a printing speed. However, bidirectional printing has a plurality of nozzle rows in which a plurality of nozzles are arranged in the paper feed direction of the printing medium, and a color inkjet print head in which each nozzle row discharges ink of a different color has the same effect as the forward movement. There is a problem that the color overlapping order is reversed at the time of the backward movement, and the hue is changed. In order to solve this problem, Japanese Patent Publication No. 3-76226 is disclosed. This method has the effect of making it difficult to recognize a change in hue because interlaced recording reverses the order of color overlap for each raster in the paper feed direction.

[0003]

However, in the bidirectional printing, dot landing position accuracy is deteriorated due to mechanism accuracy, variation in speed of ejected ink droplets, and unevenness and roughness occur, resulting in poor image quality. There is a problem of deterioration. On the other hand, many ink jet recording apparatuses make it possible to select bidirectional recording or recording only in the forward movement, and the user responds by selecting according to his / her own preference. However, the user checks the hue by performing trial printing in bidirectional recording,
After that, when the final printing is performed with only the forward movement recording in which no unevenness or roughness occurs, it is unacceptable that the hue changes between the bidirectional printing and the recording only with the reciprocating movement. Tokuhei 3-762
In Japanese Patent Publication No. 26, the difference in hue is obvious when compared with the forward movement, because it is not noticeable during bidirectional recording.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an ink-jet printhead having a plurality of nozzle rows for discharging at least two or more colors of ink, and an ink-jet printhead comprising a recording medium. A print head moving unit that reciprocates in the width direction of the print medium, a recording medium conveying unit that conveys the recording medium, and 1 / K (K
Is an integer of 2 or more), and a first scan for forming a dot and an m-th scan (a scan complementary to the first scan) are performed.
print data control means for forming one raster by scanning of (m is an integer of 2 or more) and controlling not to form dots of at least two different colors at substantially the same position in one scanning;
Selecting means for selecting reciprocating printing or printing only during forward movement.

Also, one raster is formed by scanning m = 3,
One of the three scans is characterized by arranging dots at twice the density of the other scans.

[0006]

FIG. 1 shows an embodiment of an ink jet recording apparatus used in the present invention, wherein 1 is a print head, 2 is a print head fixing base, and 3 to 5 print head moving means. 3 is a carriage belt, 4 is a motor,
5 is a carriage driving circuit for driving the motor 4, 6 to 9
Reference numeral 6 denotes a recording medium conveyance unit, 6 denotes a platen roller, 7 denotes a belt, 8 denotes a motor, 9 denotes a recording medium conveyance control circuit for driving the motor 8, 10 denotes a recording medium, and 11 denotes print data control means. The circuit 12 is a selection circuit as a selection means. The motor 4 is driven by the carriage drive circuit 5, and the print head fixing table 2 and the print head 1 that are in contact with the carriage belt 3 operate in the width direction of the recording medium 10. During this operation, the print head 1 operates according to the print data from the print data
The ink droplet is ejected to a predetermined position. When this scanning is completed, the recording medium transport control circuit 9 drives the motor 8 to move the recording medium 10 by a predetermined amount. The selection circuit 1
Reference numeral 2 determines whether bidirectional recording or recording only for forward movement is performed by an external switch (not shown).

FIG. 2 is a diagram showing an arrangement of nozzles of a print head. Reference numeral 20 denotes a nozzle, and # 1, # 2, # 3,... Are nozzle numbers.

The recording method according to the present embodiment will be described with reference to FIGS. 2 is PASS1-7, FIG.3 is PASS7-
FIG. 11 is a diagram showing the relative movement of the print head 1 of FIG.

In this embodiment, nine nozzles are arranged in one row, and Cya
3 that discharges each color of n, Magenta, and Yellow
Printhead with rows of nozzles, P = 720DP
This is an example in which I (DPI = dot / inch), K = 4, and m = 3. Reference numeral 21 denotes a dot formed on the recording medium. The movement of the print head 1 indicates a relative movement with respect to the recording medium 10.

In PASS1, the print head 1 moves in the forward movement direction. At this time, the nozzles in the printable state are only the nozzle # 9, and the nozzle # 9 is located on the raster of raster number 3. (PASS1 of the raster data table assigned to each PASS in FIG. 3). While moving, the print head 1 ejects ink droplets from the nozzle 20 for each color according to a signal of the print data control circuit 11 to form dots. At this time, Cyan has a print resolution of 720D as shown in FIG.
The dots are arranged at a pitch of half the PI and 360 DPI. On the other hand, Magenta responds to Cyan dots
At a position shifted by 720 DPI in the print head moving direction,
The dots are arranged at a pitch of 1/4 of the printing resolution of 720 DPI and 180 DPI. Yellow is Magenta
At a position shifted by 360 DPI in the print head moving direction with respect to the
Dots are arranged at a pitch of 0 DPI. After the print head 1 has finished moving in the width direction, the recording medium transport control circuit 9 feeds the recording medium 3/720 DPI as shown in FIG.
Start PASS2, which moves in the opposite direction to SS1.

In PASS2, as shown in FIG.
The nozzle is located on the raster of raster number 2 and the nozzle # 9 is located on the raster of raster number 6. (PASS2 of the raster data table assigned to each PASS in FIG. 4). While moving, the print head 1 ejects ink droplets from the nozzle 20 for each color according to a signal of the print data control circuit 11 to form dots. At this time, Magenta has a print resolution of 720 DP
Dots are arranged at a pitch of half of I and 360 DPI.
On the other hand, Yellow responds to the dots of Magenta
At a position shifted by 720 DPI in the print head moving direction,
The dots are arranged at a pitch of 1/4 of the printing resolution of 720 DPI and 180 DPI. Cyan is shifted by 360 DPI in the print head moving direction with respect to the yellow dot, and is １ ／ of the printing resolution 720 DPI, 180 DP
Dots are arranged at a pitch of I. After the print head 1 has finished moving in the width direction, the recording medium transport control circuit 9 feeds the recording medium 3/720 DPI as shown in FIG.
PASS3, which moves in the opposite direction (the same direction as PASS1), is started.

In PASS3, as shown in FIG.
Nozzle is raster number 1, # 8 nozzle is raster number 5, #
Seven nozzles are located on the raster of raster number 9. (FIG. 4
Of raster data table assigned to each PASS
SS3). While moving, the print head 1 ejects ink droplets from the nozzle 20 for each color according to a signal of the print data control circuit 11 to form dots. At this time, Yellow
In w, dots are arranged at a pitch of 360 DPI, which is half the printing resolution of 720 DPI. Meanwhile, Cyan is Yellow
At a position shifted by 720 DPI in the print head moving direction with respect to the dot of w, １ ／ of the printing resolution 720 DPI,
The dots are arranged at a pitch of 180 DPI. Mage
nta is a print resolution of 720 DP at a position shifted by 360 DPI from the cyan dot in the print head moving direction.
The dots are arranged at a pitch of 1/4 of I and 180 DPI. FIG. 6 shows a dot arrangement diagram at this time. Raster number 1
In each of the rasters Nos. 1 to 3, all dots of each color are not arranged at substantially the same position, and are formed.

Similar to PASS1 to PASS3, raster data is assigned to each nozzle as shown in FIG.
FIG. 7 shows a dot formation diagram when the process is completed up to 1. For simplicity, the dots of each raster number are divided and shown for each PASS, but they actually overlap in ascending order of PASS number. The dots of each color are in the moving direction of the print head 1, and in the raster of raster number 2, Magenta, Yel
dots overlapping in the order of low, Cyan, Yellow,
Dot, Mag overlapping in the order of Cyan, Magenta
Dots overlapping in the order of enta, Yellow, Cyan, and dots overlapping in the order of Cyan, Magenta, Yellow are repeatedly arranged. Raster number 2 in FIG.
As shown in the table of color overlap order, there is no dot overlap in the same scan, so that the same hue can be obtained without changing the dot color overlap order in both bidirectional printing and forward-only printing.

In this embodiment, as shown in FIGS.
Although the description has been made using the print heads 1 arranged in the order of an row, Magenta row, and Yellow row, this order may be any order, for example, the Magenta row, the Yellow row,
A similar effect can be obtained even in the order of cyan columns.

In this embodiment, Cy is used in PASS1.
An is recorded at twice the density of Magenta and Yellow, and in PASS2, Magenta is Yellow.
w, Cyan, Yellow is M in PASS3
Agent and Cyan were recorded at twice the density, and the method described below was repeated.
An is recorded at twice the density of Magenta and Yellow, and in PASS 4 to 6, Magenta is Yellow.
ow and Cyan, in PASS7-9, Yellow
The same effect can be obtained by a method in which w is recorded at twice the density of Magenta and Cyan, and is repeated thereafter.

FIGS. 9 and 10 show another embodiment of the present invention. FIG. 9 shows PASS1 to PASS5, and FIG.
FIG. 9 is a diagram showing relative movements of the print head 1 up to 8; Further, in this embodiment, Cyan, Mag
enta, Yellow and a print head having three rows of nozzles for ejecting each color, P = 720 DPI (DPI
= Dot / inch), K = 2, m = 2.

In PASS1, the print head 1 moves in the forward movement direction. At that time, the nozzles in the printable state are # 9, # 1
Nozzle # 0, nozzle # 9 is located on raster # 1, and nozzle # 10 is located on raster # 5. (PASS of raster data table assigned to each PASS in FIG. 11)
S1). While moving, the print head 1 ejects ink droplets from the nozzle 20 for each color according to a signal of the print data control circuit 11 to form dots. At this time, Cyan arranges dots at a pitch of 360 DPI, which is half the printing resolution of 720 DPI. Meanwhile, Magenta, Yellow
w is a print resolution of 720 DPI at a position shifted by 720 DPI in the print head moving direction with respect to the cyan dot.
, Dots are arranged at a pitch of 360 DPI.
After the print head 1 has finished moving in the width direction, the recording medium transport control circuit 9 moves the recording medium to 5 / 720D as shown in FIG.
PI feed, PAS moving in the opposite direction to PASS1
Start S2.

In PASS2, as shown in FIG.
Nozzle 8 is raster number 2, nozzle # 9 is raster number 6,
The nozzle # 10 is located on the raster of raster number 10.
(PASS2 of the raster data table assigned to each PASS in FIG. 11). While the print head 1 is moving, the nozzle 20 is provided for each color in accordance with a signal of the print data control circuit 11.
To form dots. At this time, P
As in ASS1, Cyan arranges dots at a pitch of half the printing resolution of 720 DPI and 360 DPI. on the other hand,
Magenta and Yellow arrange dots at a pitch of half the printing resolution of 720 DPI and 360 DPI at a position shifted by 720 DPI from the cyan dot in the print head moving direction.

Raster number 1 formed by the above operation
FIG. 12 shows the overlapping order of the dots of the raster of FIG. Magenta and Ye in the shaded portion of the dot overlap table for bidirectional printing and the dot overlap for only the forward movement in FIG.
Although llow, that is, Red is inverted, the order of overlapping other colors does not change and the effect is not small.

[0020]

As described above, according to the present invention, the hue does not change between bidirectional recording and recording only during forward movement, and the user can perform bidirectional recording and recording only during forward movement according to the intended use. The present invention provides an ink jet recording apparatus which can perform printing by using an ink jet printer.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a diagram showing relative movement (PASS1 to PASS7) between an ink jet print head of the present invention and a recording medium.

FIG. 3 is a diagram showing relative movement (PASS 7 to 11) between an ink jet print head of the present invention and a recording medium.

FIG. 4 is a diagram showing the correspondence between nozzle numbers and raster numbers for each pass.

FIG. 5 is a dot image diagram after pass1.

FIG. 6 is a dot image diagram after pass3.

FIG. 7 is a dot image diagram after pass12.

FIG. 8 is a diagram showing a color overlapping order according to the present invention.

FIG. 9 is a diagram showing relative movements (PASS1 to PASS5) between an ink jet print head and a recording medium according to another embodiment of the present invention.

FIG. 10 is a view showing relative movement (PASS5 to 8) between an ink jet print head and a recording medium according to another embodiment of the present invention.

FIG. 11 is a diagram showing the correspondence between nozzle numbers and raster numbers for each pass according to another embodiment of the present invention.

FIG. 12 is a diagram showing a color overlapping order according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head 2 Carriage shaft 3 Carriage belt 4 Motor 5 Carriage drive circuit 6 Platen roller 7 Belt 8 Motor 9 Recording medium conveyance control circuit 10 Recording medium 11 Print data control circuit 12 Selection circuit

Claims (2)

[Claims] An ink jet print head having a plurality of nozzle rows for discharging at least two or more colors of ink, a print head moving means for reciprocating the ink jet print head in a width direction of a recording medium, and a recording medium. The recording medium conveying means for conveying, and 1 / K (K
Is an integer of 2 or more) and a m-th scan (m) in which a dot is formed in a complementary relationship with the first scan.
Is an integer of 2 or more), forms one raster, and print data control means for controlling not to form dots of at least two different colors in substantially the same position in one scan, and prints in a reciprocating manner, or An ink jet recording apparatus comprising: a selection unit that selects printing only during forward movement. 2. A method according to claim 1, wherein one raster is formed by m = 3 scans, and one of the three scans arranges dots at twice the density of the other scans. Inkjet recording device.