JP3236034B2 - Ink jet recording method and ink jet recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method and an ink jet recording apparatus having a recording head provided with a plurality of discharge ports, and performing recording by discharging ink onto a recording material.

[0002]

2. Description of the Related Art In recent years, OA equipment such as computers, word processors, and copying machines have become widespread, and many recording methods for these recording apparatuses have been developed. The ink jet recording apparatus has an excellent feature that high definition is easy, high speed, excellent in quietness, and inexpensive as compared with other recording methods. The need for color is also growing. Many color inkjet recording apparatuses have been developed. Ink jet recording devices form images by ejecting ink from nozzles and attaching ink to recording paper,
In order to improve the recording speed, a recording head in which a plurality of recording elements are integrated and arranged (hereinafter, referred to as a multi-head) in which a plurality of ink ejection ports and liquid paths are integrated is used. The above-mentioned multi-head is generally used.

However, unlike a monochrome printer that prints only characters, printing a color image image requires various elements such as color development, gradation, and uniformity. Regarding uniformity in particular, slight variations in the nozzle unit caused by differences in the multi-head manufacturing process affect the amount of ink ejected from each nozzle and the direction of the ejection direction when printing, and eventually the printed image Causes unevenness in image quality as density unevenness.

A specific example will be described with reference to FIGS. In FIG. 12A, reference numeral 91 denotes a multi-head, which includes eight multi-nozzles 92.
Numeral 93 denotes an ink droplet ejected by the multi-nozzle 92. Normally, it is ideal that the ink is ejected in a uniform direction with a uniform ejection amount as shown in FIG.
If such ejection is performed, dots of uniform size are landed on the paper surface as shown in FIG. 12B, and a uniform image without density unevenness is obtained as a whole. (FIG. 12C). However, in actuality, as described above, each of the nozzles has a variation in the discharge amount, the discharge direction, and the like. If printing is performed in the same manner as described above, FIG. As shown, the size and direction of the ink drops ejected from the nozzles vary, and the ink drops land on the paper as shown in FIG. 13B. According to this diagram, there are blank portions that do not periodically satisfy the area factor of 100% in the main scanning direction of the head, or dots overlap more than necessary, or as seen in the center of the diagram. White streaks have occurred. The collection of dots landed in such a state has the density distribution shown in FIG. 13C with respect to the nozzle and the direction, and as a result, these phenomena usually show the density unevenness as seen by human eyes. Is sensed as

Therefore, the following method has been devised as a measure against the density unevenness. The method will be described with reference to FIGS. According to this method, the multi-head 91 is scanned three times to complete the printing area shown in FIGS. 12 and 13, but an area of half a pixel unit is completed in two passes. In this case, the multi-head 8 nozzles are divided into upper 4 nozzles and lower 4 nozzles.
The dots printed by one nozzle in one scan are obtained by thinning out prescribed image data by about half according to a predetermined image data arrangement. At the time of the second scan, dots are printed according to the remaining half of the image data.
Complete printing in pixel unit area. The above recording method is hereinafter referred to as a divided recording method.

When such a recording method is used, even if a head having the same printing characteristics as the multi-head shown in FIG. 13 is used, the influence on the print image unique to each nozzle is reduced by half. The image thus obtained is as shown in FIG.
Black streaks and white streaks as seen in FIG. 3 (b) become less noticeable. Therefore, the density unevenness is considerably reduced as shown in FIG.

When performing such recording, the first scan and the second scan
In the scan, the image data is divided in such a manner that the image data is complemented with each other in accordance with a certain arrangement. Usually, this image data arrangement (thinning-out pattern) is exactly a staggered lattice for each pixel in the vertical and horizontal directions as shown in FIG. It is most common to use something like this. Accordingly, in the unit print area (here, in units of four pixels), printing is completed by the first scan for printing the staggered grid and the second scan for printing the inverted staggered grid. FIGS. 15 (a), (b) and (c) show how the recording of a certain area is completed when the staggered and inverted staggered patterns are used, as in FIGS. This has been described using a multi-head having a. First, in the first scan,
The staggered pattern is recorded using the nozzle. (Figure 1
5 (a)). Here is the staggered pattern

[Outside 1] Expressed by

Next, in the second scan, the paper is fed by the amount of the pixel (1/2 of the head length), and the inverted staggered pattern is printed using the upper four nozzles and the lower four nozzles (FIG. 15).
(B)). Here, the inverted zigzag pattern is represented by ○. 3 more
At the scan time, the paper is fed again for four pixels (1/2 of the head length) again, and the staggered pattern is recorded again. (FIG. 15 (c)). In this manner, by sequentially performing paper feed in units of four pixels and recording in a zigzag or inverted zigzag pattern, a recording region in units of four pixels is completed for each scan. As described above, by completing printing in the same region using two different types of nozzles, it is possible to obtain a high-quality image without density unevenness.

[0009]

However, in the above conventional example, it is possible to reduce the density unevenness caused by the landing accuracy such as the deflection and the ejection amount. However, the inks of different colors can be appropriately overlapped with each other. There is a problem that color unevenness is regularly generated when solid printing of an intermediate color that is performed by adjacent printing is performed.

FIG. 16 shows a conventional printing method by head division (hereinafter referred to as L / n paper feed printing method, where n indicates the number of divisions).

In this method, the recording area (L) of the recording head is divided into two parts. In each recording head, a zigzag or inverted zigzag portion is recorded by the first scan as shown in FIG. This is a method in which feeding is performed and the remaining inverted staggered or staggered portions are printed by different nozzles in the second scan, and printing is completed. In the figure, although the ejection port array cannot be seen originally, it is shown in a transparent manner from above for convenience of explanation.

More specifically, in this case, first, printing is performed in a zigzag manner by a nozzle in the recording area (1) of each recording head by a first scan for half an hour. Here, the paper is fed in the width of L / 2. In the second scan, each print head performs printing by thinning out the print image in half in an inverted staggered manner in both the print areas (1) and (2). At this point, printing is completed in the portion (2) of the recording area. L / 2 width paper is fed. In the third scan, printing is performed by thinning out again in a zigzag pattern in the entire recording area, and the same is repeated thereafter. In FIG. 16, the display in parentheses in the second scan and the third scan indicates a portion that has been printed in the past.

Next, the reason why the intermediate color unevenness is caused in this conventional example will be schematically described with reference to a case where an eight-nozzle multi-nozzle head is used. Here, as a recorded image, FIG.
A description will be given of a case where solid printing of an intermediate color (yellow green) superimposed with a printing duty of Cy 62.5% and Y 100% as shown in FIG. When the intermediate color shown in FIG. 5A is divided into two using a staggered grid mask, the result is as shown in FIGS. 5B and 5C, which are overprinted by two scans. Here, (B) is called zigzag, and (C) is called inverted zigzag. When these (B) and (C) are viewed by recording head, FIGS. 5D and 5E and FIGS. 5F and 5G
Is discharged as shown in FIG.

FIG. 17 schematically shows the ejection positions of the Cy recording head and the Y recording head at the first scan in the L / 2 paper feed printing method and the resulting dot formation state on the recording medium. The vertical stripe pattern indicates that Cy and Y are recorded in the same pixel. In the first scan, each print head uses the four nozzles of the print area (1) and discharges in a staggered manner, and as a result, dots in which Cy and Y overlap are formed in a staggered manner on the print medium. Here, the paper is fed in the width of L / 2, and the dots recorded in the first scan move toward the recording area (2).

FIG. 18 schematically shows the ejection position in the second scan and the resulting dot formation state on the recording medium. The vertical stripe pattern indicates that Cy and Y are recorded on the same pixel, and the diagonal pattern indicates that Cy and Y are recorded only on Y.

At this time, printing is performed in reverse zigzag in all the recording areas (1) and (2). Then, as a result, the recording area (2)
Then, the printing is completed by overlapping the dots printed in a zigzag pattern in the first scan. Here, the sheet is fed in the width of L / 2, the recording area (2) moves out of the recording area, and the recording area (1) moves toward the recording area (2).

It should be noted here that when another dot is superimposed on the dot recorded earlier, the dot struck later than the previously recorded dot has a greater depth in the overlapping portion. It tends to sink in the vertical direction. FIG. 20 is a cross-sectional view schematically showing this. This is because dyes such as dyes in the ejected ink are physically and chemically bonded to the recording medium, but at this time, the bonding between the recording medium and the dyes is finite, and the bonding strength depends on the type of dye. As long as there is no significant difference, the ink dye previously ejected and the recording medium are prioritized, so that a large amount remains on the surface of the recording medium. It is thought that it sinks and dyes in the depth direction.

Therefore, also in FIG. 18, the dots recorded in the second scan are represented so as to overlap below the dots recorded in the first scan.

FIG. 19 schematically shows the ejection position at the third scan and the resulting dot formation state on the recording medium.

At this time, printing is performed in a zigzag direction opposite to the second scanning in all the recording areas (1) and (2). Then, as a result, in the printing area (2), the printing is completed by overlapping the dots printed in the reverse staggered manner in the second scan.

However, at this time, although the same amount of ink is applied to the portion of the recording region (2) and the portion outside the recording region where printing has been completed in the second scan before the recording region (2), the tint is low. Different color unevenness has occurred.

This is because a portion outside the recording area is printed in a zigzag pattern first, so that there are many portions where Cy and Y are ejected to the same pixel on the surface of the recording medium. It is probable that the portion (2) became yellow-green, which has a relatively strong yellowish color, because many portions recorded only with Y existed on the surface of the recording medium.

As described above, the conventional L / n
The paper feed printing method has a problem that inappropriate color unevenness occurs in the intermediate color, which causes deterioration of a color recorded image.

The present invention has been made in view of the above points,
An object of the present invention is to provide an ink jet recording method and an ink jet recording apparatus capable of preventing color unevenness and recording a high quality image.

[0025]

In order to solve the above-mentioned problems, an ink jet recording method according to the present invention comprises a plurality of discharge ports for discharging a first color ink arranged in a main scanning direction. Main scanning is performed by using a first recording head having a first recording head and a second recording head having a plurality of ejection ports for ejecting ink of a second color to execute color image recording on a recording material. In the ink jet recording method for transporting the recording material in a sub-scanning direction different from the main scanning direction after the main scanning is completed, a plurality of ejection ports arranged in a direction different from the main scanning direction may include a plurality of blocks for each recording head. , And as a mask pattern of a dot arrangement corresponding to each of the plurality of blocks, the blocks have a mutually complementary relationship, and this relationship is defined by the first recording head and the second recording head.
Using the same mask pattern as the print head, printing a color image thinned out in accordance with the mask pattern of each block of the first print head and the second print head in each main scan, By performing the main scanning of the same predetermined region on the recording material a plurality of times and conveying the recording material corresponding to the block, the blocks are sequentially used from the upstream side in the sub-scanning direction. An inkjet recording method characterized by forming an image.

Further, according to the recording apparatus of the present invention, it is preferable that the first recording device is arranged in the main scanning direction and arranged in a direction different from the main scanning direction.
A first recording head having a plurality of ejection openings for ejecting ink of the first color, and a plurality of ejection openings for ejecting ink of a second color arranged in a direction different from the main scanning direction. And performing color image recording by performing main scanning a plurality of times in the main scanning direction on the same predetermined area on the recording material using the second recording head, which differs from the main scanning direction after the main scanning is completed. In an ink jet recording apparatus that conveys the recording material in the sub-scanning direction, the plurality of ejection ports are divided into a plurality of blocks for each recording head, and the blocks have a mutually complementary relationship as a dot arrangement mask pattern. Using the same mask pattern between the recording heads, driving means for driving each of the recording heads based on the thinned-out color image data, and relatively moving each of the recording heads and the recording material. Transport means for transporting in accordance with the lock, and performing the main scanning a plurality of times on the same predetermined area on the recording material, while the driving means uses the mask pattern to thin out the data. The recording head is driven on the basis of the above, and the recording material is conveyed by the conveying means, thereby recording and forming an image sequentially from the block on the upstream side in the sub-scanning direction. It is a recording device.

Thus, the plurality of blocks of the first recording head and the second recording head always eject ink onto the recording material in the same order of ejection.

[0028]

The present invention will be described below with reference to examples. It should be noted that these examples are for describing the present invention more specifically, and embodiments are not limited thereto.

FIG. 10A is a perspective view showing a schematic configuration of an ink jet recording apparatus to which the present invention can be applied. In this figure, reference numeral 701 denotes an ink cartridge. These are composed of ink tanks packed with four color inks, black (BK), cyan (Cy), magenta (M), and yellow (Y), respectively, and a multi-head 702 corresponding to each color. FIG. 10B shows a state of the multi-nozzles arranged on the multi-head from the z direction. FIG. 10B shows a multi-nozzle 801 arranged on the multi-head 702. Returning again to FIG. Reference numeral 703 denotes a paper feed roller which rotates in the direction of the arrow in the figure while holding down the print paper P together with the auxiliary roller 704, and feeds the print paper P in the y direction as needed. Reference numeral 705 denotes a paper feed roller which feeds printing paper and
As in the case of 04, it also serves to suppress the printing paper P. A carriage 706 supports the four ink cartridges and moves them together with printing. This is the home position h at the position indicated by the dotted line in the figure when printing is not being performed or when multi-head recovery work is performed.
It is designed to wait.

Here, the 4 mounted on the carriage 706
The individual inkjet cartridges are arranged so that the inks are superposed in the order of black ink, cyan ink, magenta ink, and yellow ink. The color intermediate color can be realized by appropriately overlapping the ink dots of Cy, M, and Y. That is, red can be realized by overlapping M and Y, blue can be realized by overlapping Cy and M, and green can be realized by overlapping Cy and Y.

In general, black can be realized by superimposing the three colors of Cy, M, and Y. However, if the color of black is poor at this time, it is difficult to superimpose with high precision, so that chromatic color fringing occurs and the unit time Because the density of the ink is too high, only black is separately ejected.

FIG. 11 is a block diagram showing a control section of the ink jet recording apparatus shown in FIG. 20 in the figure
A control unit 1 mainly includes a CPU, a ROM, a RAM, and the like, and controls each unit of the apparatus according to a program stored in the ROM. Reference numeral 202 denotes a driver for driving the carriage motor 205 for moving the carriage 706 in the x direction (main scanning) based on a signal from the control unit 201. Reference numeral 203 denotes a paper feed roller 705 and a feeding roller based on a signal from the control unit 201. A driver 204 drives a paper roller 703 to drive a transport motor 206 for transporting (sub-scanning) the recording material in the y direction. A driver 204 drives the multi-color heads 207 to 210 based on print data from the control unit 201. And 211, an operation display unit for performing various key inputs and various displays, and 212, a host device for supplying print data to the control unit 201.

Before the start of printing, the carriage 706 at the position (home position) shown in FIG.
The multi-nozzles 801 perform printing for each recording area divided on the paper surface. When printing of data to the end of the sheet is completed, the carriage returns to the original home position, and performs printing in the x direction again. After the first printing is completed and before the second printing starts, the paper feed roller 703 is used.
Rotates in the direction of the arrow to feed the paper in the y direction by the width of the divided recording area. In this manner, data printing on one sheet is completed by repeating the printing by the multi-head and the paper feeding (sub-scanning) for each one scan (main scan) of the carriage.

FIG. 1 shows the recording control method in this embodiment in detail. First, printing is performed in a zigzag manner by a nozzle in the recording area (1) of each recording head for half a minute by the first scan. Here, the paper is fed in the width of L / 2.
In the second scan, each print head prints in a staggered manner in the print area (1) as in the first scan, and prints in the print area (2) by thinning out the print image in half in an inverted staggered manner. At this point, printing is completed for the portion recorded in the recording area (2). Further, the paper is fed in the width of L / 2. In the third scan, as in the second scan, printing is performed by thinning out in a staggered manner in the printing area (1), and printing is performed in a staggered manner in the printing area (2), and printing is performed in the printing area (2). Is completed. Hereinafter, the same is repeated. In FIG. 1, the display in parentheses at the second scan and the third scan indicates a portion printed in the past. By doing so, the same driving order is always obtained, so that color unevenness does not occur.

Next, the reason why the intermediate color unevenness does not occur in this embodiment will be described in more detail schematically in the case of using a multi-nozzle head having eight nozzles. Here, similarly to the description of the conventional example, a case where solid printing of an intermediate color (yellow green) superimposed at a print duty of Cy62.5% and Y100% as shown in FIG. explain.

FIG. 2 shows the ejection positions of the Cy recording head and the Y recording head at the first scan in the L / 2 paper feed printing method of this embodiment, and the resulting dot formation state on the recording medium. This is schematically shown, and a vertical stripe pattern indicates that Cy and Y are recorded in the same pixel. First
At the scanning time, each print head uses the four nozzles of the print area (1) and discharges in a staggered manner. As a result, dots in which Cy and Y overlap are formed in a staggered manner on the print medium. Here, the paper is fed in the width of L / 2, and the dots recorded in the first scan move toward the recording area (2). So far there is no difference from the conventional example.

FIG. 3 schematically shows the ejection position in the second scan and the resulting dot formation state on the recording medium. The vertical stripe pattern indicates that Cy and Y are recorded on the same pixel, and the diagonal pattern indicates that Cy is recorded only on Y.

At this time, in the printing area (1), zigzag printing is performed in the same manner as in the first scan, but in the printing area (2), printing is performed in reverse zigzag, opposite to the printing area (1).

As a result, in the printing area (2), the inverted staggered dots are superimposed on the dots printed in a staggered manner in the first scan, and the printing is completed. Here, the sheet is fed in the width of L / 2, the recording area (2) moves out of the recording area, and the recording area (1) moves toward the recording area (2).

It should be noted here that when another dot is superimposed on the previously recorded dot, the dot struck later than the previously recorded dot has a greater depth in the overlapping portion. It tends to sink in the vertical direction. Therefore,
Also in FIG. 3, the dots recorded in the second scan are represented so as to overlap below the dots recorded in the first scan. FIG. 4 schematically shows the ejection position at the third scan and the resulting dot formation state on the recording medium. At this time, the staggered printing is performed in the printing area (1), and the printing area (1) is printed in the printing area (2), as in the second scanning.
On the contrary, it prints in reverse zigzag.

As a result, in the recording area (2),
In the second scan, the inverted staggered dots are superimposed on the dots printed in a staggered manner, and the printing is completed. Accordingly, at this time, the reverse hound's-tooth is similarly applied to the portion of the printing region (2) and the portion outside the printing region where the printing has been completed in the second scan before the same, so that the tint is changed. It becomes uniform and no color unevenness occurs.

Therefore, while taking advantage of the feature of reducing the density unevenness caused by the landing accuracy and the ejection amount of the L / n paper feed printing due to the deviation, etc., by appropriately overlapping and adjacent inks of different colors, It has become possible to realize good color image recording without the occurrence of regular color unevenness that occurs when solid printing of a possible intermediate color is performed.

In this embodiment, the print is thinned out in a zigzag pattern like a zigzag or inverted zigzag, and the print is fixed at zigzag in the recording area (1) and inverted zigzag in the recording area (2). However, the thinning method is not limited to the houndstooth check. That is, as shown in FIG. 6, when the recording area (1) is fixed to a certain thinning method, the remaining area is always printed in the recording area (2), and the recording image is completed by being printed in both recording areas. Just do it.

FIG. 7 shows another example of a thinning pattern.
Here, as in the first embodiment, a case will be described in which a solid image of an intermediate color (yellow green) superimposed with a print duty of Cy62.5% and Y100% as shown in FIG. . In this embodiment, the intermediate colors shown in FIG. 7A are thinned out as shown in FIGS. 7B and 7C, and the thinned-out intermediate colors are printed in two scans. Here, (B) is called thinning out, and (C) is called thinning out. Looking at these (B) and (C) by recording head, FIG.
(E) and discharge as shown in FIGS. 7 (F) and 7 (G). At this time, the thinning pattern may be printed in the recording area (1), and the thinning pattern may be printed in the recording area (2).

In the present invention, the thinning rate in each print area of each print head is set to 50% so that a print image is completed by two scans. In order to improve the print quality, consider the case where the thinning printing rate in each area is set to, for example, 75% and 150% is obtained in two scans, or the amount of shots is reduced to eliminate the blur of the ink boundary. Then, the thinning-out printing rate may be set to, for example, 40%, and the ejection amount may be suppressed to 80% in two scans.

FIG. 9 shows a second embodiment of the present invention.
3 shows a recording method according to the embodiment.

In this method, the recording area L of the recording head is divided into four parts. In each recording head, a portion thinned out to 25% by the first scan is recorded, and after that, the paper is fed L / 4 width, and the second scan is performed. In the scan, another 25% is printed by a different nozzle, the paper is fed by L / 4 width, and another 2% is printed in the third scan.
In this method, 5% is printed, the paper is fed by L / 4 width, and the remaining 25% is printed in the fourth scan to complete the printing.

In the figure, the ejection port array cannot be seen originally, but is shown from above for convenience of explanation.

FIG. 8 shows an example of a method of thinning out 25% thinning in the present embodiment, in which the landing position and the order of landing are represented by numerals. That is, in the recording area (1), printing is performed at the position, in the recording area (2), printing is performed at the position, printing is performed at the position of the recording area (3), and printing is performed at the position of the recording area (4). The printing in a certain area is completed by the carriage scanning.

More specifically, referring to FIG. 9, in this case, first, printing is performed by thinning out to 25% by the nozzles in the recording area (1) of each recording head by the first scanning. At this time, the 25% thinning method prints a portion corresponding to the position shown in FIG. 8, and FIG. 9 shows K, C, and M, respectively.
, Y. Here, the portion recorded in the recording area (1) where the L / 4 width paper is fed moves to the recording area (2). In the second scan, printing is performed in the recording areas (1) and (2). At this time, printing is performed at the position of the thinning pattern in the recording area (1), and the recording area (2) is shown in FIG. The portions corresponding to the positions of the thinning patterns are printed (in FIG. 9, indicated as K, C, M, and Y, respectively). Here, the sheet is fed in the width of L / 4, and the portion of the recording area (2) moves to the recording area (3), and the portion recorded in the recording area (1) moves to the recording area (2).
Subsequently, in the third scan, the recording areas (1), (2),
Printing is performed in the area (3). Here, in the recording area (3), portions corresponding to the positions shown in FIG. 8 are printed by 25% thinning-out printing (in FIG. 9, K, C, M, and K, respectively).
Indicated as Y. In the recording area (1), printing is performed at the position of the thinning pattern, and in the recording area (2), a portion corresponding to the position of the thinning pattern shown in FIG. 8 is printed. Here, the paper is fed in the width of L / 4, and the portion recorded in the recording area (3) goes to the recording area 4, the part recorded in the recording area (2) goes to the recording area (3), and the recording area (1). The part recorded in ()) moves to the recording area (2). Subsequently, in the fourth scan, the recording area (1),
Printing is performed in all the areas (2), (3) and (4). Here, in the recording area (4), portions corresponding to the positions shown in FIG. 8 are printed by 25% thinning printing (K, C, M, and Y are respectively shown in FIG. 9), and the recording area (1) is printed. )
Prints at the position of the thinning pattern, prints a portion corresponding to the position of the thinning pattern in the recording area (2), and prints a portion corresponding to the position of the thinning pattern in the recording area (3). At this time, the printing of the portion recorded in the recording area (4) is completed, and the L / 4
The paper is fed in the width, and the printing is repeated in the same manner.

In FIG. 9, the display in parentheses at the second, third, and fourth scans indicates the portion printed in the past scan.

In this embodiment, when the image recording is completed in the recording area (4), the recording is always completed in the order of thinning-out → thinning-out-thinning → thinning-out, so that the color becomes constant and uniform. Therefore, the problem of color unevenness does not occur.

In the present embodiment, 1 is compared with the first embodiment.
Because the amount of ink applied in each scan is reduced,
In addition, ink and ink of different colors can be used while taking advantage of the feature that no border bleeding occurs, and that the density unevenness caused by the landing accuracy and ejection amount of the L / n paper feed printing due to the deviation is reduced. It has become possible to realize good color image recording without the occurrence of regular color unevenness that occurs when solid printing of an intermediate color is performed by appropriately overlapping and adjacent printing.

The present invention brings about an excellent effect particularly in an ink jet recording apparatus which performs recording by forming flying droplets by utilizing thermal energy among ink jet recording methods.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding nucleate boiling to an electrothermal transducer arranged corresponding to the sheet or liquid path in which This is effective because heat energy is generated in the electrothermal transducer, causing film boiling on the heat-acting surface of the recording head, and as a result, air bubbles in the liquid (ink) corresponding one-to-one to this drive signal can be formed. It is. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600 which discloses a configuration in which the heat acting portion is arranged in a bending region may be adopted.

In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and absorbs pressure waves of thermal energy. A configuration based on JP-A-59-138461, which discloses a configuration in which an opening corresponds to a discharge unit, may be used.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by combining a plurality of recording heads as disclosed in the above-mentioned specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition, the print head is replaceable with a print head of a replaceable chip type, which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge type recording head provided with an ink tank is used.

It is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., since the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof, and recording Performing a preliminary ejection mode for performing another ejection is also effective for performing stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be a single recording head or a combination of plural recording heads. Alternatively, the device may be provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or below and which softens at room temperature, or which is liquid, In the ink jet method, the temperature of the ink itself is generally controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. May be a liquid.

In addition, the temperature rise due to thermal energy is positively prevented by using it as energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. Either ink may be used, or in any case, the ink may be liquefied by application of heat energy according to the recording signal and ejected as a liquid ink, or may already start to solidify when reaching the recording medium. Alternatively, the ink may be liquefied for the first time by thermal energy. In such a case, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be combined with a reader or the like in addition to the above-described one provided as an image output terminal of an information processing device such as a word processor or a computer. A copier, or a facsimile machine having a transmission / reception function may be used.

[0066]

As described above, by carrying out the present invention, there is no occurrence of density unevenness due to the landing accuracy of the print head or the like or the discharge amount, and regular color unevenness due to the order of ink ejection. Good color image recording became possible.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a recording method according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an ejection position in a first scan and a dot formation state at that time in the first embodiment.

FIG. 3 is a schematic diagram showing an ejection position in a second scan and a dot formation state at that time in the first embodiment.

FIG. 4 is a schematic diagram illustrating an ejection position in a third scan and a dot formation state at that time in the first embodiment.

FIG. 5 is an explanatory diagram of a thinning method.

FIG. 6 is a supplementary schematic explanatory view of the recording method according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of another thinning method.

FIG. 8 is an explanatory diagram of a thinning method in the second embodiment.

FIG. 9 is a schematic explanatory diagram of a recording method according to a second embodiment of the present invention.

FIG. 10 is a schematic explanatory view of an ink jet recording apparatus to which the present invention is applied.

11 is a block diagram illustrating a control unit of the inkjet recording apparatus illustrated in FIG.

FIG. 12 is a diagram of an ideal printing state of the ink jet printer.

FIG. 13 is a diagram illustrating a printing state of an inkjet printer having uneven density.

FIG. 14 is an explanatory diagram of reduction of density unevenness by the L / n paper feed printing method.

FIG. 15 is an explanatory diagram of reduction of density unevenness by the L / n paper feed printing method.

FIG. 16 is a schematic explanatory view of a conventional L / n paper feed recording method.

FIG. 17 is a schematic diagram showing a discharge position in a first scan and a dot formation state at that time in a conventional L / n paper feeding method.

FIG. 18 is a schematic diagram illustrating a discharge position in a second scan and a dot formation state at that time in a conventional L / n paper feeding method.

FIG. 19 is a schematic diagram showing a discharge position in a third scan in a conventional L / n paper feeding method and a dot formation state at that time.

FIG. 20 is a cross-sectional view of a recording medium illustrating how dots overlap.

[Explanation of symbols]

 701 Ink tank 702 Multi head 703 Paper feed roller 705 Paper feed roller 706 Carriage

Continuing from the front page (72) Inventor Kiichiro Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shigetasu Nagoshi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-3-45351 (JP, A) JP-A-58-194541 (JP, A) JP-A-4-226367 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/21 B41J 2/01 B41J 2/485 B41J 19/18

Claims (4)

(57) [Claims] A first recording head provided in the main scanning direction and having a plurality of ejection ports for ejecting a first color ink; and a plurality of ejection ports for ejecting a second color ink. A main scan is performed using a second recording head having an ejection port to execute color image recording on a recording material, and after the main scanning is completed, the recording material is transported in a sub-scanning direction different from the main scanning direction. In the inkjet recording method, a plurality of ejection ports arranged in a direction different from the main scanning direction are divided into a plurality of blocks for each recording head, and a mask pattern of a dot arrangement corresponding to each of the plurality of blocks is provided between the blocks. The first print head and the second print head use a mask pattern that has the same relationship between the first print head and the second print head. A color image that is thinned out according to the mask pattern of each block of the recording medium is recorded, and the same predetermined area on the recording material is main-scanned a plurality of times while corresponding to the block. An ink jet recording method, wherein an image is formed by transporting the recording material to use each of the blocks sequentially from an upstream side in the sub-scanning direction. 2. The ink jet recording method according to claim 1, wherein the first and second recording heads discharge the ink from the discharge ports by causing a state change in the ink by thermal energy. 3. A first recording head having a plurality of ejection ports arranged in a main scanning direction and arranged to eject ink of a first color arranged in a direction different from the main scanning direction; The same predetermined area on the recording material in the main scanning direction by using a second recording head having a plurality of ejection ports for ejecting a second color ink arranged in a direction different from the direction. In an ink jet recording apparatus that performs color image recording by performing main scanning a plurality of times and conveys the recording material in a sub-scanning direction different from the main scanning direction after the main scanning is completed, the plurality of ejection ports are provided for each recording head. Are divided into a plurality of blocks, and as a mask pattern of a dot array, there is a mutually complementary relationship between the respective blocks, and the same mask pattern is used between the respective print heads. Record A drive unit for driving a head; and a transport unit for transporting each of the recording heads and the recording material relatively corresponding to the block, wherein the same predetermined area on the recording material is moved a plurality of times. By performing the main scanning, the driving unit drives each of the recording heads based on the data thinned out using the mask pattern, and conveys the recording material by the conveying unit. An ink jet recording apparatus, which records images sequentially from the blocks on the upstream side in the sub-scanning direction to form an image. 4. The ink jet recording apparatus according to claim 3, wherein the first and second recording heads cause the ink to be ejected from the ejection ports by causing a state change of the ink by thermal energy.