JPH06312517A - Ink jet recording device and method - Google Patents

Abstract

PURPOSE:To obtain an excellent image without irregularity in density. CONSTITUTION:In a first record scanning (going printing) of a record head, ink is discharged by using only thick ink for forming an image. In a second record scanning (returning printing), ink is discharged by using only thin ink in the same area for forming the image. Thereafter, a recording paper is conveyed for a predetermined quantity. In repeating the above, an excellent image without irregularity in density due to the putting order of the thick and thin inks can be obtained.

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 apparatus and an ink jet recording method, and more particularly to an invention for forming a good color image by simultaneously using high density ink and low density ink.

[0002]

2. Description of the Related Art With the widespread use of copying machines, word processors, information processing equipment such as computers, and communication equipment, an ink jet type recording head is used as one of image forming (recording) equipment of these equipment. Those that record digital images are rapidly spreading. In such a recording apparatus, in order to improve the recording speed, a recording head in which a plurality of recording elements are integrated and arrayed is generally used as a recording head in which a plurality of ink ejection ports and liquid paths are integrated.

In this type of recording method, a dot density control method in which the number of recording dots per unit area is controlled by recording dots of a fixed size to express a halftone, or a size of recording dots is controlled to express a halftone. The halftone recording control is performed by the dot diameter control method.

Here, the latter dot diameter control method has a constraint that complicated control for subtly changing the size of a recording dot is required. Therefore, the former dot density control method is generally used. It is used.

Further, as an ink ejecting means, it is easy to manufacture and high density is possible, so that it is possible to realize high resolution by electric
When a thermal energy converter is used, it is difficult to control the amount of pressure change and the diameter of the recording dot cannot be modulated, so recording is performed by the dot density control method.

The systematic dither method is one of the representative halftone expression binarization methods used in the dot density control method, but this method has a problem that the number of gradations is limited by the matrix size. There is. That is, it is necessary to increase the matrix size in order to increase the number of gradations, but if the matrix size is increased, there is a problem in that one pixel of a recorded image formed by one matrix becomes large and the resolution is impaired. It was Another typical binarization method is a conditional decision type dither method such as an error diffusion method. This is an independent decision type dither method in which the systematic dither method described above is binarized by using a threshold value unrelated to the input pixel, whereas the threshold value is changed in consideration of the peripheral pixels of the input pixel. Is the way. The conditional decision type dither method represented by this error diffusion method has good compatibility of gradation and resolution, and when the original image is a printed image, a moire pattern is extremely rare in the recorded image. Although it has advantages, there is a problem in that the graininess is likely to be noticeable in the bright area of the image, and the image quality is poorly evaluated. This problem was particularly remarkable in a recording device having a low recording density.

Therefore, in order to make the above-mentioned graininess inconspicuous, a conventional ink jet recording apparatus is provided with two recording heads for respectively ejecting light-colored ink and dark-colored ink, and from the light portion to the halftone portion of the image. A recording method has been proposed in which recording dots are formed with light-colored ink and recording dots are formed with dark-colored ink from the halftone portion to the dark portion.

FIG. 7 shows the construction of the printer unit when printing on the paper surface with the above-mentioned multi-head. Here, it is assumed that the four recording heads for four colors are provided in the recording scanning direction for color correspondence. In this figure, reference numeral 701 is an ink cartridge. These are 4
The recording head 702 includes an ink tank in which color inks of different colors, black, cyan, magenta, and yellow are respectively filled in dark ink and light ink.

FIG. 2 shows the state of the ejection ports arranged on the recording head in the z direction. Here, there are two rows of ink for all four colors, such as a dark ink ejection row and a light ink ejection row on the black head, and a dark ink ejection row and a light ink ejection row on the cyan head adjacent to the black head. The outlets are arranged. Here, the heads of each color including the dark and light discharge ports are shown to be independent,
For example, even if the ejection ports of each density for each color are all arranged on the same head, if the arrangement of the ink ejection ports has the same configuration as described above, the image forming state is also the same.

Returning to FIG. 7 again. A paper feed roller 703 rotates in the direction of the arrow in the figure while holding the print paper 707 together with the auxiliary roller of 704, and feeds the print paper 707 in the y direction at any time. A paper feed roller 705 is used to feed the print paper and, like 703 and 704, print paper 70
It also plays the role of suppressing 7. Reference numeral 706 is a carriage that supports four ink cartridges and moves them with printing. This is to stand by at the home position (h) at the position shown by the dotted line in the figure when printing is not performed, or when multi-head recovery work is performed.

Before the start of printing, the carriage 706 at the position shown in the figure (home position) moves in the x direction when a print start command arrives, and n on the multi-head 702 moves.
The width D is recorded on the paper surface by the multi-nozzles.
This recording is according to the reading timing of the encoder,
The above-mentioned invention element is driven based on a recording signal to eject and attach ink droplets on a recording material in the order of dark black, light black, dark cyan, light cyan, dark magenta, light magenta, dark yellow, and light yellow. By doing so, an image is formed. When the data printing is completed up to the edge of the paper, the carriage returns to the original home position, and printing is performed again in the x direction (forward scanning direction). Or if it is double-sided printing, −
Printing is performed while moving in the x direction (reverse scanning direction). From the end of the first printing to the start of the second printing, the paper feed roller 703 rotates in the arrow direction to feed the paper in the y direction by the width D. In this way, printing of only the multi-head width D and paper feeding are repeated for each scan of the carriage, whereby data printing on one paper surface is completed.

However, in such a method, eight kinds of ink drops are landed on the recording paper in the same scanning, and therefore, in a recording pixel of a mixture of two colors such as red, green, and blue, the maximum concentration of the dark ink and the light ink is 400. The record of% duty is 1
Sometimes it is done every time. Therefore, not only the bleeding of dots in each pixel becomes large, but also the bleeding at the boundary between different colors becomes worse, the linearity is lost at the boundary between different colors, and the image is likely to deteriorate.

Therefore, a multi-pass printing method has already been devised, in which all the pixels to be printed by the same printing scan are divided into a plurality of groups, and printing is performed while drying the same printing area little by little by a plurality of printing scans. Such multi-pass printing is effective for all ink jet recording apparatuses in that ink is dried little by little, even if it is not configured to have both dark ink and light ink used in the present invention. is there. In particular, the effect is great in recording on plain paper or OHP paper that absorbs ink slowly.

However, even if the recording is simply divided into two times, the time cost related to the recording is doubled, and such a situation is not preferable for the recording apparatus. Therefore, as a method of simply shortening the printing time, bi-printing in which printing is performed by both forward and backward scanning of the carriage is considered.

The construction and effect of this are described in US Pat. No. 4,748.
No. 453, which has already been disclosed. Here, the first and second
Ink beading (adjacent dots) on a medium such as OHP paper is performed by performing complementary recording on pixels that are alternately positioned in the horizontal and vertical directions in the same recording area by (or more) divided recording scans. And the color banding (color irregularity) is prevented by reversing the ink ejection order of the color mixture pixels between the first scan and the second scan (reciprocal printing) when forming a color image. The effect that can be done is described.

On the other hand, in Japanese Laid-Open Patent Publication No. 58-194541, a plurality of recording element arrays are arranged in parallel and reciprocally run in a direction perpendicular to the recording element arrays to perform main scanning for dot matrix recording. At least one dot in each row and each column of the recording dot matrix is intermittently recorded in the forward path of the main scanning, and at least each of the rows and each column in the return path of the main scanning. Recording by intermittently recording the remaining dots on one side so that the order of recording overlap in the overlapping recording dots by the plurality of recording element arrays is made different between the forward pass and the return pass of the main scan. A method is disclosed. Also in this case, it is effective to prevent image deterioration due to color tone deviation (color unevenness) of recorded images due to overlapping recording of color inks. Further, although not limited to a color printer, it is not disclosed in JP-A-55-113.
Japanese Patent No. 573 also discloses a configuration in which reciprocal recording is performed using a checkered (staggered, inverted zigzag) pattern. In this case, it is an object to prevent adjacent dots from being continuously printed, thereby preventing the dot distortion by printing the adjacent dots before the printed dots are dried.

The color banding and the color tone deviation to be solved by the above invention are both related to the order in which ink colors are printed, and the heads of respective colors as shown in FIG. 2 are arranged in order in the recording scanning direction. That was an inevitable problem. This will be described below.

FIG. 3 is a sectional view showing the landing state of the recording ink which is generally used at present and the medium (paper) for printing the recording ink. Here, a case is shown in which two different color inks (ink drops that are filled in with black are shaded) are absorbed (recorded) at almost adjacent positions on the recording medium P with a time lag. The point to be noted is that, in the overlapping portion of two dots, the dots that are hit later than the dots that are recorded first tend to sink in the depth direction of the paper surface. This is a stage where the dyes such as dyes in the ejected ink are physically and chemically bonded to the recording medium. Since the bond between the recording medium and the dyes is finite, there is a large difference in the bonding force depending on the kind of the dyes. As long as there is no ink, the amount of ink dye ejected earlier remains on the surface of the recording medium because it is prioritized, and the ink dye ejected later does not easily bond on the surface of the recording medium, and It is thought that it sinks in the direction and is dyed. In this case, even if two types of ink are printed at the same landing point, the priority colors differ depending on the order of the two types of ink ejection, and as a result
I have expressed two different colors. For example, when forming a green (cyan + yellow) image in a certain area, when ink is applied to each pixel in the order of cyan and yellow, the cyan absorbed first becomes the priority color, and the tint of cyan is strong. It becomes a green image. However, conversely, when ink is applied in order of yellow and cyan, a green image having a strong yellow tint can be obtained.

When printing in both directions, the recording head is
Since the ink is fixed in the print scanning direction as shown in (3), the order in which ink is printed in the forward path and the order in which ink is printed in the reverse path are reversed. Therefore, the tint of the dots printed on the outward path and the tint of the dots printed on the backward path are different. In this state, when the paper is fed by the head width (D) for each print scan,
Two different colors and densities appear alternately for each head width,
This caused large unevenness on the whole and deteriorated the image.

However, according to the above-described conventional invention, all the print pixels in the image area which can be printed by one print scan are printed while weaving dots of different colors in the forward pass printing and the backward pass printing. Depending on the order of driving the colors as above,
Harm is eliminated. Further, the effect of recording while drying the ink little by little can be achieved in the same printing time as the normal one-sided printing.

The phenomenon that the dot landing state differs depending on the ink firing order described above is not limited to color unevenness, and the same applies to two drops of ink having different densities. When the high-density ink is recorded first, the dot shape of this ink is given priority, and a clear image with high density can be obtained. On the other hand, when a high-density ink is printed after being hit with a low-density ink, it bleeds around the low-density ink to a large extent, and a smooth and uniform image with a low density is obtained. Of.

Therefore, the above-mentioned multi-pass printing method can be expected to have a good effect even in a color printing apparatus, or in the case of printing only a single color of black using plural kinds of inks having different densities. .

In the multi-pass printing method described above, the recording head is scanned a plurality of times at the same position on the paper surface to complete the image. The multi-pass printing method is further developed and divided. The recording method is raised. This will be explained below.

Unlike a character printer that prints only characters, a color printer requires various elements such as color developability, gradation, and uniformity in printing an image. Particularly regarding uniformity, a slight variation in nozzle unit that occurs in the multi-head manufacturing process affects the ink ejection amount and ejection direction of each nozzle when printing, and finally the printed image This causes the image quality to deteriorate as uneven density.

A specific example will be described with reference to FIGS. 9 and 10. In FIG. 9A, 91 is a multi-head,
Here, for the sake of simplicity, it is assumed that the ink jet recording device is configured by eight multi-nozzles that record only one type of ink of single color and single density. Reference numeral 93 is an ink droplet ejected by the multi-nozzle 92, and normally, it is ideal that ink is ejected in a uniform direction with a uniform discharge amount as shown in this figure. If this kind of discharge is performed, the result shown in FIG.
As shown in FIG. 9B, dots having a uniform size are landed on the paper surface, and as shown in FIG. 9C, a uniform image without density unevenness is obtained as a whole. However, in reality, as described above, each nozzle has variations, and if the same printing is performed as it is, the nozzles are ejected as shown in FIG. 10A. The sizes and directions of the ink drops vary, and the ink drops land on the paper surface as shown in FIG. 10B. According to FIG. 10 (b), in the main scanning direction of the head, there are periodically blank portions that do not satisfy the area factor of 100%, or conversely, dots are overlapped more than necessary, or It can be seen that a white streak appears in the center. The collection of dots landed in this state is
The density distribution shown in FIG. 10C is obtained, and as a result, these phenomena are perceived as density unevenness as seen by human eyes.

Further, it is difficult to always control the paper feed amount D repeated for each print scan to be constant. If the paper is fed by more than a certain amount, a single dot and a dot are recorded at a position distant from the specified amount, and that part becomes noticeable as a white stripe. On the contrary, if the paper is fed by less than a certain amount, the dots of a single portion will overlap each other more than necessary, and will be noticeable as black lines. The higher the pixel density, the tighter the control of the value of the paper feed amount, and the more noticeable it is as a connecting line on the image.

Therefore, the following divided recording method is conceivable as a countermeasure against the above-described density unevenness and connecting stripes. The method will be described with reference to FIGS. 11 and 12. According to this method, the multi-head 91 is scanned three times to complete the printing area shown in FIGS. 9 and 10. According to FIG. 11, the half 4-pixel unit area is completed in two passes. ing. In this case, the 8 nozzles of the multi-head are divided into a group of 4 upper nozzles and 4 lower nozzles,
The dots printed by one nozzle in one scan are defined image data thinned to about half according to a predetermined image data array. Then, at the time of the second scan, the dots of the other half of the image data are embedded, and the printing of the 4-pixel unit area is completed.

If such a divided recording method is used, even if the same recording head as that used in FIG. 10 is used, the influence on the print image peculiar to each nozzle is halved, so the printed image is 11 (b), and black stripes and white stripes as shown in FIG. 10 (b) become less noticeable. Therefore, as shown in FIG. 11C, the density unevenness is different from that of FIG.
Considerably eased. In addition, even if the streak for each scan in which the end nozzles are adjacent to each other is printed by the split recording method, half of the nozzles are printed by the nozzles at the end of the head and the nozzles at the center of the head. Variations in scanning
It can be halved.

When performing the above-described divided recording method or the above-described multi-pass printing method, in the first scan and the second scan, the image data is divided according to a certain arrangement so as to fill each other. As the image data array (thinning pattern), as shown in FIG. 12, it is most common to use an array in which pixels are arranged in a zigzag pattern for each vertical and horizontal pixel.

Therefore, when division recording is performed, in the unit printing area (here, in units of 4 pixels), printing is completed by the first scan for printing the zigzag lattice and the second scan for printing the inverse zigzag lattice. It is what is done. 12 (a), 12 (b) and 12 (c) show how recording of a certain area is completed when using this zigzag and inverse zigzag pattern, respectively. Similarly, the description is given using a multi-head having 8 nozzles. First, in the first scan, using the lower 4 nozzles, a staggered pattern ○
Is recorded (FIG. 12A). Next, in the second scan, the paper is fed by 4 pixels (1/2 of the head length) and the reverse zigzag pattern is printed (FIG. 12B). Further, in the third scan, the paper is fed by 4 pixels (head length 1/2) again, and the staggered pattern is recorded again (FIG. 12).
(C)). In this way, paper feeding in units of 4 pixels and printing of staggered and reverse zigzag patterns are alternately performed, thereby
The recording area in pixel units is completed for each scan.
As described above, by completing printing with two different types of nozzles in the same area, it is possible to obtain a high-quality image without density unevenness.

Such a divided recording method has already been disclosed in Japanese Patent Laid-Open No.
It is disclosed in Japanese Patent Laid-Open No. 107975 and US Pat. No. 4,967,203, and it is stated that its effect on density unevenness and connecting lines is also effective. Regarding the former, "a means for forming paper overlap in each main scan by making the paper feed smaller than the width of the main scan and overlapping two adjacent main scans and a print dot in the overlap two times. It is characterized in that a means for arranging them so that they do not overlap in scanning is provided. " According to this case, as already explained,
In some cases, the thinning mask is set to "print odd rows and even rows alternately in every other column", but in addition, odd rows are printed in the first main scan and even rows are printed in the second scan. In some cases, printing may be performed randomly in each scan, and the thinning mask and paper feed width are not completely limited.

On the other hand, the latter US Pat.
In No. 3, “a) in the first pass, only the upper half of the first swath prints alternating pixel positions that are not horizontally and vertically adjacent, and b) in the second pass, in the first swath Pixels that were not printed in the first pass and alternating horizontal and vertical non-adjacent pixels in the lower half of the first swath, c) Print in the first and second passes in the third pass Print the pixels in the first swath that were not done,
We will make a first pass on the sash that immediately follows. " In this U.S. patent, an alternating pixel array which is not adjacent in the vertical and horizontal directions is defined as a thinning mask for division recording.

As a configuration to be added in this US patent, pseudo pixels (superpixels) are collectively formed by several pixels for gradation expression and multicolor expression, and pseudo pixels (superpixels) are not adjacent in the horizontal and vertical directions. A recording method for performing alternate thinning printing is disclosed. According to this method, "Once the system for realizing the above method is installed in either program software or printer formware,
Since the program can read in a specified combination of color numbers for superpixels, this print quality is achieved without unduly complicating the task of creating a computer program to produce multiple colors. "And simplifies programming for multi-colored expressions. It also states that color bleeding within a superpixel is harmless because each superpixel is intended to be perceived as a single, homogeneous color.

As described above, by performing the multi-pass printing method or the divided recording method in both line printing, a plurality of types of inks having different densities can be obtained even in the color recording apparatus or in the case of single color printing of black only. When used for recording, good effects can be expected.

[0035]

However, in the case of a structure in which dark, light inks of yellow, magenta, cyan, and black are recorded at the same time, that is, a total of eight types of ink are recorded at the same time, the ink is divided into one reciprocating scan. In many cases, there is not enough time for the product to dry sufficiently.

Not only that, when the amount of ink ejected per pixel increases, the amount of bleeding into other pixel regions also increases, and for example, even when only 50% of the entire region is recorded as shown in FIG. 4, Almost all areas will be covered. In such a state, the ink that can be easily scanned in the opposite direction sneaks into the lower side of the paper according to the principle already described with reference to FIG. It will end up.

If the divisional printing method is used, the area which is first printed by the forward scan and then the backward scan and the area which is first printed by the backward scan and then the forward scan are printed. Areas and areas appear alternately at a pitch half the recording width of the head, resulting in significant color unevenness in the paper feed direction.

Further, the above-mentioned color unevenness does not appear in the case of single-color printing, but when recording is performed using two types of ink having different densities, there is a difference in the bleeding of both inks on the paper surface. In many cases, that is, even in the case of a single color, uneven density may appear in the paper feeding direction depending on the order of ink injection of both.

Therefore, the number of divisions is further increased, and two round trips are made.
A method of printing with 4 reciprocating recording scans can be considered, but if this is done, the recording time related to printing will increase more and more,
There is a problem that the effect of printing in both directions is diminished.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording apparatus and an ink jet recording method capable of obtaining a good image without density unevenness.

[0041]

According to the present invention for achieving the above object, a recording head capable of ejecting a plurality of inks having different densities is used, and the recording is performed while the recording head is relatively reciprocally scanned on a recording medium. An ink jet recording apparatus for forming an image by ejecting ink from a head onto a recording medium, wherein in one of the reciprocating scans, an ink having a desired density is ejected among the inks having a plurality of densities to form an image. In the other scan of the reciprocating scan, the ink having a density different from the desired density among the plurality of density inks is ejected to the image area formed using the ink having the desired density. Ink ejection control means for forming an image is provided.

According to the present invention, a recording head capable of ejecting a plurality of inks having different densities is used, and ink is ejected from the recording head to the recording medium while the recording head is relatively reciprocally scanned on the recording medium. An ink jet recording apparatus for forming an image by the following reciprocal scanning, in which ink of a desired density is ejected from the plurality of density inks to form an image, and in the next reciprocal scanning performed after the reciprocal scanning. An ink ejection control unit that ejects an ink having a density different from the desired density among the inks having the plurality of densities to the image area formed by using the ink having the desired density. An inkjet recording apparatus is provided which is characterized by the above.

[0043]

According to the present invention, in one of the reciprocal scans, an ink having a desired density is ejected from a plurality of inks having a plurality of densities to form an image, and in the other scan of the reciprocal scans, the desired density ink is ejected. An image having a density different from the desired density among the plurality of density inks is ejected onto the image area formed using the density ink to form an image.

According to another aspect of the invention, in reciprocal scanning, an ink having a desired density is ejected from inks of a plurality of densities to form an image, and in the next reciprocal scanning performed after the reciprocal scanning, An image having a density different from the desired density among the plurality of density inks is ejected onto the image area formed using the desired density ink to form an image.

Therefore, it is possible to obtain a good image without density unevenness due to the order in which the dark ink and the light ink are ejected.

[0046]

Embodiments of the present invention will be specifically described below with reference to the drawings.

(First Embodiment) FIG. 5 is an explanatory view of the construction of an ink jet unit (recording head) used in this embodiment.

One end of the wiring board 200 is connected to the wiring portion of the heater board 100, and the wiring board 2 is further connected.
A plurality of pads corresponding to the respective electric / thermal energy converters for receiving an electric signal from the recording apparatus main body are provided at the other end of 00. As a result, the electric signal from the recording apparatus main body is supplied to each electric / thermal energy converter.

The metal support 300, which supports the back surface of the wiring board 200 on a flat surface, serves as the bottom plate of the ink jet unit. The presser spring 500 is a claw for hooking the area near the ink discharge port of the groove top 1310 by elastically pressing a line in a U-shaped section and an escape hole formed in the base plate to elastically press the area. The base plate has a pair of rear legs that receive the force acting on the spring.

By this spring force, the wiring board 200 and the groove 1
It is in pressure contact with 310.

The wiring board 200 is attached to the support by adhesion with an adhesive or the like.

A filter 700 is provided at the end of the ink supply pipe 2200.

The ink supply member 600 is formed by molding, and the groove top 1310 is formed with a flow path for guiding the ink to each ink supply port. To fix the ink supply member 600 to the support 300, the two pins (not shown) on the back surface side of the ink supply member 600 are attached to the holes 190 of the support 300.
This is easily performed by projecting through each of 1 and 1902 and heat-sealing them.

At this time, the gap between the orifice plate portion 1300 and the chip tank 600 is formed uniformly.
The sealant was injected from the upper sealant injection port of the ink supply member 600 to seal the wire bonding and at the same time to seal the gap between the orifice plate portion 1300 and the chip tank 600, and further provided on the support substrate 300. Groove 31
0, the orifice plate portion 1300 and the support base 3
00 Completely seal the gap with the front end.

FIG. 6 is a perspective view of the groove top 1310 of the head unit used in this embodiment as seen from the heater board 100 side. Two liquid chambers are provided, and each liquid chamber is partitioned by a wall 20a. Each liquid chamber is provided with supply ports 20b and 20c for supplying ink.

A groove 20d is provided on the pressure contact surface of the wall 20a partitioning each liquid chamber with the heater board 100. This groove communicates with the outer peripheral portion of the groove top 1310. Mizoten 1
After 310 is pressed against the heater board and brought into close contact therewith, the outer peripheral portion is sealed with the sealant as described above. At this time, the sealant penetrates along the groove to fill the gap between the groove top 1310 and the heater board 100. in this way,
The liquid chamber can be completely separated by the technical process conventionally used in the head. The structure of this groove differs depending on the physical properties of the sealant, and it is necessary to make the shape corresponding to each.

By thus dividing the liquid chamber into a plurality of chambers, different inks can be supplied to the respective ink ejection ports.

FIG. 13 is a block diagram showing the arrangement of the color ink jet recording apparatus in this embodiment.

In the figure, reference numeral 161 denotes an image input section for optically reading an original image by a CCD or the like, or for inputting an image luminance signal (RGB) from a host computer, a video device or the like, and 162 indicates setting of various parameters and start of printing. 3 illustrates an operation unit including various keys for supporting the. Reference numeral 163 denotes a CPU which controls the entire recording apparatus according to various programs in the ROM and constitutes an ink ejection control unit. Reference numeral 164 denotes a ROM that stores a program for operating the recording apparatus according to the control program / error processing program. In this ROM, 164a is an input gamma conversion table for reference in the processing of an input gamma conversion circuit described later,
64b is a masking coefficient to be referred to in the processing of a color correction (masking) circuit which will be described later, and 164c is black generation and U which will be described later.
A black generation and UCR table referred to in the processing of the CR circuit, 164d indicates a light and shade distribution table for reference in the processing of a light and shade distribution circuit, which will be described later, and 164e indicates a program group that stores the various programs described above. Reference numeral 165 denotes a RAM used as a work area for various programs in the ROM and a temporary save area during error processing. Reference numeral 166 denotes a processing unit that performs image signal processing to be described later, and 167 denotes a printer unit that forms a dot image based on the image signal processed by the image signal processing unit during recording. Reference numeral 168 denotes a bus line for transmitting address signals, data, control signals and the like in this device.

Next, the image signal processing section will be described.
FIG. 8 shows an example of an image signal processing circuit in the color ink jet recording apparatus in this embodiment.

The red image brightness signal R, the green image brightness signal G, and the blue image brightness signal B are converted into a cyan image density signal C, a magenta image density signal M, and a yellow image density signal Y by an input gamma correction circuit. To be converted.

Color correction (masking) circuit, black generation / UC
After performing color processing in the R (under color removal) circuit, new image density signals C of cyan, magenta, yellow, and black,
Convert to M, Y, K. The image density signals C, M, Y, and K of the cyan, magenta, yellow, and black images that have been gamma-corrected by the output gamma correction circuit are dark cyan, dark magenta, dark yellow, and dark black with high dye density in the dark / light distribution circuit. The image density signals Ck, Mk, Yk, Kk and the image density signals Cu, Mu, Yu, Ku of light cyan, light magenta, light yellow, and light black having low dye density are distributed.

FIG. 14 is a diagram for explaining an example of the density distribution table in the density distribution circuit.

This table is set so that the image density signal value and the optical reflection density value of the image after recording show a proportional linear relationship. Based on this density distribution table, the image density signals C, M, Y and K are distributed to the density signals by the density distribution circuit. The image density signals distributed to the respective shades are binarized by a binarization circuit, input to each inkjet unit, and ink is ejected from the corresponding ink ejection port array according to the signal value to form a color image. It

The printing state of this embodiment is shown below. In this embodiment, the divided printing method as described in the conventional example is not performed, and after 100% printing of dark ink is always completed in the forward scan,
Light ink 10 in the backward scan without paper feed scanning
Record 0%. After dark ink black → cyan → magenta → yellow is printed in the forward scan in all image areas, the light ink yellow → magenta → cyan → black is completed in the backward scan, so all colors,
In principle, density unevenness due to the order of ink ejection does not appear.

FIG. 1 shows a state in which a uniform green image is recorded in such a state. The uniform green image referred to here is an image in which both dark ink and light ink are recorded for both cyan and yellow. In FIG. 14B, the input image density signal is between 128 and 255. Refers to duty. However, in the following details including the present embodiment, a state in which the above-described four types of ink are recorded in all pixels is set for convenience of explanation.

A brief description will be given below for each recording scan in FIG. The first print scan is a forward scan, and only the 4-color dark ink head in the print head of FIG.
The entire head width (8 pixel width) area is printed. At this time,
Ink having a higher density is landed in this region in the order of cyan and yellow, and a green image having a strong cyan tint is obtained. The next second print scan is a backward scan, in which dark ink has already been printed in the first print scan and yellow and cyan are printed in this order only with light ink.

By the above reciprocal scanning, the recording of the image area of the head width (8 pixel width) is completed, and the ink is deposited on the image area in the order of dark ink cyan, dark ink yellow, light ink yellow, and light ink cyan. As a result, a uniform image in which the dark ink cyan recorded first is the priority color is obtained.

After the above-described one set of reciprocal recording scan, the recording paper is fed in the direction of the arrow by the head width (8 pixel width). Then, again, ink is landed on the second image area adjacent to the first image area in the order of dark ink cyan, dark ink yellow, light ink yellow, and light ink cyan in the same order as the first image area. A uniform image having the same tint as that of the first image area in which dark ink cyan is the most preferential color is obtained.

In the same manner, printing of each image area by one set of reciprocating printing scans and paper feeding with a width of 8 nozzles are repeated, so that a uniform green color without density unevenness and density unevenness can be obtained in the previous print area. An image is obtained.

According to the present embodiment, the forward scan is always described as dark ink and the backward scan is as light ink. However, in the sense that the order in which the inks are ejected is aligned, the forward scan is performed with light ink and the backward scan is performed. Even if a method of recording dark ink is adopted, the same effect can be obtained. In this case, it is already described that the ink is similarly printed in each image region in the order of light ink cyan, light ink yellow, dark ink yellow, and dark ink cyan, and a uniform green image is obtained in all image regions. This is similar to the case where dark ink is printed by the forward scan. However, in this case, since the light ink is recorded first, the light ink cyan is the most preferential color, and a lighter and smoother image with less graininess is obtained as a whole.

Which of the above two types of printing methods is better is not important, but the character quality etc. is regarded as important as a whole, and when it is desired to obtain a sharp resolution, the dark ink is generally used in the forward printing. Therefore, when a smooth image is desired to be obtained, the light ink is recorded by the forward printing so that an image suitable for each purpose can be obtained.

Furthermore, in the present embodiment, the case where a uniform green image is formed has been described as an example. However, for example, even in monochromatic printing in which an image is formed using dark ink and light ink of only black. The effects of this embodiment can be similarly obtained.

According to the present embodiment described above, a total of eight types (two types for a single color) of ink having different colors and densities are arranged in the entire image area in a row of head widths (here, 8 pixel widths). By making the values uniform, it is possible to obtain a good and uniform image without the appearance of color unevenness and light and shade unevenness as in the conventional example.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The purpose of this embodiment is to regulate the ejection of dark ink and light ink in a reciprocating manner and to use the divided recording method to obtain this effect at the same time.

The head structure of this embodiment is the same as that shown in FIG. In the present embodiment, as in the first embodiment, a head in which eight nozzles are arranged in one row is used. However, since the divided printing method is used here, the paper feed amount for each printing scan is half that of the first embodiment, that is, four. It has a pixel width.

FIG. 15 shows a printing state when recording is performed in this embodiment. Here, as in the case of the first embodiment, the case where a uniform green image is recorded in cyan and yellow is taken as an example.

The first print scan is a print scan in the forward direction, and only 4 out of 8 nozzles are used and 50% of all print pixels are printed.
Only record. The image area recorded at this time is referred to as a first image area. As shown in the figure, these pixels are obtained by arranging pixel groups obtained by hardening 1 × 2 pixels into one just in a staggered manner. By doing so, it is possible to reduce the bleeding to areas other than the printing pixels in each printing scan as compared with the arrangement shown in FIG. 4 in which one pixel unit is staggered. It is less likely to happen.

In the second recording scan, the paper feed is not performed, and the light ink is printed in the backward pass by the four nozzles again on the first image area.
The pixel to be recorded at that time is the same pixel as that on which dark ink has already been recorded on the return path, and the ink is landed in this order in the order of light ink yellow and light ink cyan. The pixels of the first image area printed by the first and second reciprocating scans are ink-shot in the order of dark ink cyan → dark ink yellow → light ink yellow → light ink cyan, and the image area as a whole is 50%. Dark ink cyan is the priority color.

Before the next third recording scan, the head 1/2
A paper feed scan of width (4 pixel width) is entered. Then, again, in the order of dark ink cyan and dark ink yellow in the forward direction, 50% is simultaneously recorded in the first image region and the second image region by using 8 nozzles. At this time, in the first image area in which 50% of the printing has already been completed in the first and second printing scans, the remaining 50% pixels that have not been printed are used for printing in the first printing scan. Print with different nozzles.

In the next fourth recording scan, the paper feed scan is not performed, and the dark ink is recorded again in the backward direction in the order of light ink yellow and light ink cyan on the pixels for which the dark ink has already been recorded on the outward path.

When the fourth recording scan is completed, the recording of the first image area is completed. Reconsidering the ink recording order in the first to fourth recording scans in the first image area, dark ink cyan → dark ink yellow → light ink yellow → light ink cyan → dark ink cyan in all pixels. Ink drops are ejected onto the paper in the order of dark ink yellow, light ink yellow, light ink cyan. Therefore, even in the state where the divided recording is performed by the reciprocal printing, in this embodiment, only the dark ink is specified in the forward path, and only the light ink is specified in the backward path. That is, a green image having a strong cyan tint is obtained in which the dark ink cyan, which is the ink color to be recorded, is a preferential color in the entire image area.

In the next fifth printing scan and sixth printing scan as well, printing similar to the third and fourth printing scans is performed on the second image area and the third image area, and the second image area is also the first image. It is possible to obtain a green image in which dark ink cyan has a priority color and is equal to the area.

At the stage where the image areas are completed by the printing scans which are successively performed in this way, all the image areas are printed in the same ink ejection order, the dark ink cyan becomes the priority color, and the entire image is also obtained. A uniform and smooth product is obtained.

Further, since the divided recording method is used in this embodiment, the effect of improving the unevenness of the nozzle variation and the unevenness of the paper feed amount is also obtained.

As described above, according to the present embodiment, in the color ink jet recording apparatus having the dark and light ink heads, the dark ink is divided during the forward scan and the light ink is recorded during the backward scan. By using the recording method, it is possible to obtain a smooth and uniform image having no color unevenness, density unevenness, and density unevenness due to nozzle variations and paper feed amount variations.

Also in this embodiment, the recording order of the dark ink and the light ink during the forward printing and the backward printing may be reversed. Similar to the first embodiment, a characteristic image is obtained when dark ink is recorded on the outward path and then light ink is recorded on the backward path, or when light ink is recorded on the outward path and dark ink is recorded on the backward path. It becomes possible.

(Third Embodiment) A third embodiment will be described below. While the second embodiment uses the divided recording method while completely separating the scan for recording the dark ink and the scan for recording the light ink on the forward path and the return path, the present embodiment uses the divided recording method. In this method, the recording of the dark ink (or the light ink) is completely completed in each image area, and then the light ink (or the dark ink) is recorded. Figure 1
6 shows the structure of the recording head used in this embodiment.

In the present embodiment, the independent heads for each of the four colors of black (Bk), cyan (C), magenta (M), and yellow (Y) have eight nozzles for ejecting dark ink.
It has 8 nozzles for discharging light ink, 16 nozzles in total. At this time, the recording scan of the head and the paper feed are performed in the directions indicated by the respective arrows, and the paper feed is performed with a width of 4 nozzles for each recording scan.

According to the configuration of this embodiment, the recording paper is fed from the light ink print area toward the dark ink print area, so that the recording always records the dark ink image after the light ink image is completed. By thus arranging one row of dark and light inks in the paper feeding direction, the ink ejection order of the light and dark inks does not reverse in the forward and backward passes of bidirectional printing, so uneven density due to the ink ejection order should be prevented in advance. Can be done.

Printing in each printing scan will be briefly described below with reference to FIG. 17 as in the previous embodiment. In the first print scan, among the 16 nozzles in the print head, the lower half 4 nozzles of the light ink portion are used. The pixel array to be printed at this time is one in which 1 × 2 pixels are staggered as in the second embodiment.
Half of all pixels that can be recorded by the nozzle are recorded. First
In the print scan, the print head prints while scanning in the forward direction, so when printing a uniform green image, ink is ejected to each print pixel in order of cyan and yellow. Therefore, with the pixels printed in the first recording scan, a green image having a strong cyan tint can be obtained. First
After the printing scan is completed, the printing paper is fed in the direction of the arrow by a width of 4 pixels.

In the next second recording scan, printing is performed using all eight nozzles of light ink in the backward direction. The pixels printed at this time are 1 × 2 pixels in the 4-pixel width area that was not printed in the first printing scan and the 4-pixel width image area that follows.
This is a part of an array in which pixels are staggered. In the second print scan, printing is performed in the backward direction, so ink is applied to print pixels in the order of yellow and cyan. Therefore, the pixels printed in the second recording scan form a green image with a strong yellow tint. However, since the inks printed by the first and second printing scans are originally of low density, the difference in tint due to the order of ink ejection does not appear so large.

After feeding the paper with a width of 4 pixels again, the third recording scan is performed in the forward direction. The nozzles used here are all 8 nozzles of light ink and 4 nozzles of the lower half of the dark ink nozzles.
It is a nozzle. Since this printing scan is printing in the forward direction again, in the light ink areas of the second and third image areas, green pixels having a strong cyan tint can be obtained in the ink ejection order of cyan and yellow. On the other hand, in the first image area, since the light ink has already been printed and the priority color has already been determined by the light ink, even if the dark ink is ejected in the order of cyan and yellow, the priority by this is given. There is no color decision, and the density of green is high overall.

In the next fourth recording scan, all nozzles of the recording head are used for the first time. Since this recording scan is a backward scan again, ink is ejected in the order of yellow and cyan. As described in the third print scan, since the light ink has already been landed on the first image area and the second image area, the ink ejection order of the dark ink has almost no effect on the image. Only in the double-sided image area, the density of green is increased as a whole. By this print scan, printing on the first image area is completed. For the third and fourth image areas, the priority color at the print pixel is determined by the order in which the ink is ejected, as in the previous print scans.

In the same manner, all 16 print scans are performed.
Using the nozzles, paper feed scanning of 4 nozzle width and reciprocal printing are sequentially repeated.

According to the method described above, the light ink image is completed in the first two scans in the entire image area of four pixel widths, and then the dark ink image is completed in the subsequent two scans. . Therefore, the density unevenness described above does not completely appear from the beginning in this embodiment. Further, with regard to color unevenness, which is another adverse effect due to the order in which ink is ejected, it is configured to record dots of different color tones in the forward pass and the return pass, but in the present embodiment, while performing divided printing, simultaneously 1x the pixel to record
Since it is set to 2 units, it is possible to further suppress the bleeding to other areas as compared with FIG. 4 described in the conventional example.
Therefore, the ratio of the area occupied by dots printed on the outward path,
The ratio of the area occupied by dots printed in the backward pass is substantially equal in each image area, so that a better image can be obtained.

On the basis of such an idea, by further enlarging the pixel array having a size of 1 × 2 in the present embodiment and the second embodiment, it is possible to further solve the color unevenness and the light and shade unevenness. Can be predicted. In fact, in this way, the overall tint in each image area can certainly be made uniform. On the other hand, however, if the unit of the pixel array is too large, it becomes visually perceivable this time, and a rough feeling appears on the image, resulting in lack of smoothness. Therefore, as the size of this pixel array, it is preferable to use an appropriate value according to the size of one pixel itself and the amount of ink ejected to one pixel.

In the present embodiment, the two adverse effects, dark and light unevenness and color unevenness, which can occur when printing on both lines, are recorded by different scanning depending on the head configuration for the former, and printing control is performed for the latter. I am solving it.

Further, in the above description, the head configuration is used in which the light ink is first printed and then the dark ink is recorded. However, the order in which the dark and light ink is ejected is not limited to this, as in the above-described embodiment. Not a thing. That is, it is effective for the present invention and this embodiment even if the configuration is such that the positions of the light ink nozzle and the dark ink nozzle are reversed.

The present invention is particularly effective in an ink jet recording head and a recording apparatus for recording by forming flying droplets by utilizing thermal energy among the ink jet recording systems.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and the continuous type, but in the case of the on-demand type in particular, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal which corresponds to the recorded information and causes a rapid temperature rise exceeding nucleate boiling to the electrothermal converter, thermal energy is generated in the electrothermal converter, This is effective because film boiling is caused on the heat acting surface, and as a result, bubbles can be formed in the liquid (ink) that correspond one-to-one to this drive signal. Liquid (ink) flows through the ejection openings due to the growth and contraction of these bubbles.
To form at least one drop. When this drive signal is pulsed, the growth and contraction of the bubbles are performed immediately and appropriately, so the liquid (ink) with excellent responsiveness is used.
It is more preferable that the discharge can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. still,
US Patent No. 4 of the invention relating to the rate of temperature rise of the heat acting surface
If the conditions described in the specification of No. 313124 are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the heat acting portion is arranged in a bending region.

In addition, Japanese Patent Application Laid-Open No. 59-123670 discloses a structure in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and a pressure wave of thermal energy is absorbed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration in which an opening corresponds to a discharge portion.

In addition, by being attached to the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. The present invention is also effective when a cartridge-type recording head provided with an ink tank is used.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. to the recording head because the effects of the present invention can be further stabilized. Specific examples thereof include capping means, cleaning means, pressurizing or suctioning means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and recording. It is also effective to perform a stable recording by performing a preliminary discharge mode in which another discharge is performed.

In the embodiments of the present invention described above, the ink is described as a liquid, but it is an ink that solidifies at room temperature or lower and that softens at room temperature, or is a liquid, or the above-mentioned liquid. In the inkjet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. It may be in a liquid form.

In addition, the temperature rise due to the thermal energy is positively prevented by using it as the 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 ink evaporation. In any case, by applying heat energy in accordance with the recording signal, the ink is liquefied and ejected as a liquid ink, or when it reaches the recording medium, it already begins to solidify. The use of an ink which has a property of being liquefied only by energy is also applicable to the present invention. In such a case, the ink is retained as a liquid or solid in the recesses or through holes of the porous sheet as described in JP-A-54-5687 or JP-A-60-71260, It may be configured to face the electrothermal converter. 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, as a form of the recording apparatus according to the present invention, the recording apparatus according to the present invention is integrally or separately provided as an image output terminal of an information processing apparatus such as a word processor or a computer as described above, and is combined with a reader or the like. It may be in the form of a copying machine or a facsimile machine having a transmission / reception function.

FIG. 18 is a block diagram showing a schematic configuration when the ink jet recording apparatus of the present invention is applied to an information processing apparatus having a function as a word processor, a personal computer, a facsimile apparatus and a copying apparatus.
In the figure, 1201 is a control unit for controlling the entire apparatus, which includes a CPU such as a microprocessor and various I / O ports,
Control signals and data signals are output to each unit, and control signals and data signals from each unit are input for control.
A display unit 1202 displays various menus, document information, image data read by the image reader 1207, and the like on this display screen. A transparent pressure-sensitive touch panel 1203 is provided on the display unit 1202. By pressing the surface of the touch panel with a finger or the like,
This can be done by inputting items or inputting coordinate positions on the display unit 1202.

Reference numeral 1204 denotes FM (Frequency M).
The audio source section stores the music information created by a music editor or the like in the memory section 1210 or the external storage device 12.
The data is stored as digital data in 12, and is read from the memory or the like to perform FM modulation. The electric signal from the FM sound source unit 1204 is converted into an audible sound by the speaker unit 1205. The printer unit 1206 has the recording apparatus according to the present invention applied as an output terminal of a word processor, a personal computer, a facsimile apparatus, and a copying apparatus.

Reference numeral 1207 denotes an image reader unit for photoelectrically reading and inputting original data, which is provided in the middle of the original feeding path and reads various originals in addition to facsimile originals and copy originals. Reference numeral 1208 denotes a facsimile transmission / reception unit that transmits the original data read by the image reader unit or 1207 by facsimile and receives and decodes the transmitted facsimile signal, and has an interface function with the outside. A telephone unit 1209 has various telephone functions such as a normal telephone function and an answering machine function. 121
Reference numeral 0 denotes a ROM for storing a system program, a manager program, other application programs, etc., a character font, a dictionary, etc., a RAM for storing the application programs and character information loaded from the external storage device 1212, and a video RAM, etc. Is a memory unit including.

Reference numeral 1211 is a keyboard unit for inputting document information and various commands. An external recording device 1212 has a floppy disk, a hard disk, or the like as a storage medium. The external recording device 1212 stores character information, music or voice information, a user application program, and the like.

FIG. 19 is an external view of the information processing apparatus shown in FIG. In the figure, reference numeral 1301 denotes a flat panel display using liquid crystal or the like, which displays various menus, graphic information, document information and the like. A touch panel is installed on the display 1301. By pressing the surface of the touch panel with a finger or the like, coordinate input and item designation input can be performed. 1302 is a handset used when the device functions as a telephone.

The keyboard 1303 is detachably connected to the main body via a cord, and various character information and various data can be input. Also, this keyboard 13
03 is provided with various function keys 1304 and the like. 1
Reference numeral 305 is a floppy disk insertion port.

Reference numeral 1307 denotes a paper placing portion on which an original read by the image reader portion 1207 is placed, and the read original is discharged from the rear portion of the apparatus. In addition, in the case of facsimile reception or the like, the image is recorded by the inkjet printer 1307.

The display 1301 may be a CRT, but a flat panel such as a liquid crystal display using a ferroelectric liquid crystal is preferable. This is because in addition to being small and thin, it is possible to reduce the weight. When the information processing device functions as a personal computer or a word processor,
In FIG. 18, various types of information input from the keyboard unit 1211 are processed by the control unit 1201 according to a predetermined program and output as an image to the printer unit 1206. When functioning as a receiver of a facsimile apparatus, the facsimile information input from the facsimile transmission / reception unit 1208 via the communication circuit is received by the control unit 1201 according to a predetermined program, and output as a received image to the printer unit 1206.

Further, when functioning as a copying apparatus, the image reader unit 1207 reads a document, and the read document data is output as a copied image to the printer unit 1206 via the control unit 1201. When functioning as a transmitter of a facsimile machine, the original data read by the image reader unit 1207 is stored in the control unit 1.
After being transmitted according to a predetermined program by 201, it is transmitted to the communication circuit via the facsimile transmission / reception unit 1208. The information processing apparatus described above may be an integrated type in which an ink jet printer is built in the main body as shown in FIG. 20, and in this case, it becomes possible to enhance portability. In the figure, parts having the same functions as those in FIG. 19 are designated by the corresponding reference numerals.

By applying the recording apparatus of the present invention to the multifunctional information processing apparatus described above, a high-quality recorded image can be obtained, so that the function of the information processing apparatus can be further improved. Become.

[0120]

As described in detail above, according to the present invention,
It is possible to obtain a good image without density unevenness due to the order in which the dark ink and the light ink are ejected.

[Brief description of drawings]

FIG. 1 is a diagram showing a recording state according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a head configuration of the first embodiment.

FIG. 3 is a diagram showing a state of permeation into a paper surface according to an ink landing order.

FIG. 4 is a diagram showing a state where a dot oozes out when divided recording is performed.

FIG. 5 is a diagram showing an inkjet unit of the present invention.

FIG. 6 is a perspective view of groove points of the inkjet head of the present invention.

FIG. 7 is a diagram of an inkjet printer used in the present invention.

FIG. 8 is a block diagram used in the present invention.

FIG. 9 is a diagram showing an ideal printing state of an inkjet printer.

FIG. 10 is a diagram showing a printing state of an inkjet printer having uneven density.

FIG. 11 is a diagram showing division printing used in the present invention.

FIG. 12 is a diagram showing division printing used in the present invention.

FIG. 13 is an image processing circuit diagram used in the present invention.

FIG. 14 is a dark ink / light ink distribution table used in the present invention.

FIG. 15 is a diagram showing a recording state according to the second embodiment of the present invention.

FIG. 16 is a diagram showing a head configuration used in a third embodiment of the present invention.

FIG. 17 is a diagram showing a recording state according to the third embodiment of the present invention.

FIG. 18 is a block diagram showing a schematic configuration when applied to a recording device and an information processing device of the present invention.

FIG. 19 is an external view of an information processing device.

FIG. 20 is an external view showing another example of the information processing apparatus.

[Explanation of symbols]

 161 Image input unit 162 Operation unit 163 CPU 164 ROM 165 RAM 166 Image signal processing unit 167 Printer unit 168 Bus line 702 Recording head

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 9012-2C B41J 3/04 103 B

Claims (12)

[Claims] 1. An image is formed by using a recording head capable of ejecting a plurality of inks having different densities, and ejecting the ink from the recording head onto the recording medium while relatively reciprocally scanning the recording head on the recording medium. In the inkjet recording apparatus, the one of the reciprocal scans forms an image by ejecting an ink of a desired density among the plurality of density inks, and the other scan of the reciprocal scans includes: Ink ejection control means for ejecting an ink having a density different from the desired density among the plurality of density inks to an image area formed using the ink having a desired density to form an image. Characteristic inkjet recording device. 2. A recording head capable of ejecting a plurality of inks having different densities is used, and ink is ejected from the recording head to the recording medium while the recording head is relatively reciprocally scanned on the recording medium to form an image. In the inkjet recording device, the desired density is ejected in the reciprocating scan to form an image by ejecting an ink having a desired density among the inks having a plurality of densities, and the desired Ink ejection control means for ejecting an ink having a density different from the desired density among the inks having a plurality of densities to an image area formed by using the ink having a density Inkjet recording device. 3. The ink jet recording apparatus according to claim 1, wherein the recording head can eject a plurality of colors of ink, and a plurality of inks having different densities for the respective colors. 4. The recording head according to claim 1, wherein the recording head is a recording head that ejects ink by utilizing thermal energy, and includes a thermal energy converter for generating thermal energy applied to the ink. The ink jet recording apparatus according to any one of claims. 5. The recording head causes the ink to cause a state change by the thermal energy applied by the thermal energy converter, and ejects the ink from an ejection port based on the state change. Inkjet recording device. 6. An image forming apparatus comprising the ink jet recording apparatus according to claim 1 and a document image reading unit. 7. An image forming apparatus comprising the ink jet recording apparatus according to claim 1 and a transmission and / or reception unit of image information. 8. The image forming apparatus according to claim 7, further comprising a document image reading unit. 9. An image forming apparatus comprising the inkjet recording apparatus according to claim 1 and a recording signal input unit. 10. The image forming apparatus according to claim 9, wherein the recording signal input means is a keyboard. 11. An image is formed by using a recording head capable of ejecting a plurality of inks having different densities, and ejecting the ink from the recording head onto the recording medium while relatively reciprocally scanning the recording head on the recording medium. In the inkjet recording method, in one of the reciprocal scans, an image is formed by ejecting an ink of a desired density among the inks of the plurality of densities, and in the other scan of the reciprocal scans, An ink jet recording method, characterized in that an image having a density different from the desired density among the plurality of density inks is ejected onto an image area formed using an ink having a desired density to form an image. . 12. An image is formed by using a recording head capable of ejecting a plurality of inks having different densities and ejecting the ink from the recording head onto the recording medium while relatively reciprocally scanning the recording head on the recording medium. In the inkjet recording method, in the reciprocal scanning, an ink having a desired density is ejected from the plurality of density inks to form an image, and the desired reciprocal scanning is performed after the reciprocal scanning. For the image area formed using the ink of the density of
An ink jet recording method, comprising forming an image by ejecting an ink having a density different from the desired density among the inks having a plurality of density.