JPH06312518A - Ink jet recording device and method - Google Patents

Abstract

PURPOSE:To obtain an excellent image without irregularity in density. CONSTITUTION:When an image is to be formed by discharging ink on a record medium by using an ink discharge means capable of discharging a plurality of inks having different densities and when an image density to be recorded is a density for recording by discharging both colors of the same line having densities different from each other on the record medium, recording is performed by discharging the ink in such a manner that the inks do not overlap with the same picture element. Thus, as a local density difference and a peculiar irregularity in density do not occur, an image of high quality 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 for recording using inks of the same color having different densities.

[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. Further, as the image quality and color of the information equipment and the communication equipment are increased, the demand for higher quality and colorization of the recording apparatus is also increasing. In such a recording apparatus, in order to improve the recording speed, a recording head (hereinafter referred to as a multi-head) in which a plurality of recording elements are integrated and arranged is one in which a plurality of ink ejection ports and liquid paths are integrated at high density. It is common to use a plurality of the above multi-heads of cyan, magenta, yellow, and black for colorization.

However, there is a limit to high-density integration of ink ejection ports and liquid paths, and as a result, ink dots stand out in the image highlight portion, which has been a problem in terms of high-quality image recording. Therefore, as a method for achieving high image quality by devising the device configuration, instead of increasing the integration density of the ink ejection ports and liquid paths, the dots of the ejected ink are made small, and small dots are formed in the same pixel on the recording paper. A so-called multi-drop recording method has been proposed, which is a method of recording multiple times according to the recording density. In the multi-drop method, the dot diameter can be made smaller than usual, so the image quality in the highlight area is slightly improved, but there is a limit to the size of the ink that is ejected in consideration of the stabilization of ejection, and therefore the limit of image quality improvement Occurs. Further, in this method, if the dots are made smaller to improve the image quality, the number of times of overprinting is increased to obtain the maximum density, which causes a drastic decrease in the recording speed, which is a conflict between the image quality improvement and the recording speed. A relationship occurs. As a method of achieving high image quality without increasing the integration density, dark and light inks of similar colors with different dye concentrations of the ink are used to record the image highlight area with light ink to make ink dots inconspicuous and A so-called light and dark recording method has been proposed in which a dark portion having a high density is printed with dark ink to suppress a decrease in recording speed.

FIG. 4 shows a main part of a configuration example of a conventionally known ink jet recording apparatus of a gray scale recording system.
In this drawing, a carriage 706 has eight ink tanks filled with four dark and light inks of black, cyan, magenta, and yellow, and eight multi-heads for ejecting four light and dark inks. 702 is mounted. FIG. 5 shows a state of the multi-nozzles arranged on the multi-head from the z direction (paper surface side), and 801 is a multi-nozzle arranged on the multi-head 702. In this figure, the multi-nozzles 801 are arranged in parallel along the Y axis, but they may have some inclination on the XY plane of the figure, for example. In this case, while the head moves in the traveling direction X, each nozzle performs printing while shifting the timing. Return to FIG. 4 again. Reference numeral 703 denotes a paper feed roller 704
The printing paper 707 is rotated in the direction of the arrow while holding down the printing paper 707 together with the auxiliary roller, and the printing paper 707 is fed in the y direction at any time. Further, reference numeral 705 denotes a paper feed roller which feeds the printing paper and also plays a role of suppressing the printing paper 707 similarly to 703 and 704. The carriage 706 stands by at the home position (h) at the position shown by the dotted line in the figure when printing is not performed or when multihead 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 along the carriage guide shaft 708 when a print start command arrives, and based on the read signal from the linear encoder 709. By ejecting the inks of four shades of light and shade of four colors from the n multi-nozzles 801 on the multi-head 702 at timing, the width D of the print-head on the paper surface.
Just print. By this recording scan, dark black ink, light black ink, dark cyan ink,
The light cyan ink, the dark magenta ink, the light magenta ink, the dark yellow ink, and the light yellow ink are deposited in this order to form dots. When the printing of the data is completed up to the end of the paper, the carriage returns to the original home position and printing is performed again in the x direction. From the end of this first printing to the start of the second printing, the paper feed roller 703 rotates in the direction of the arrow, so that the width D is y.
Feed paper in the specified direction. 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.

FIG. 6 shows an example of an image signal processing circuit in the above-mentioned ink jet recording apparatus. The original image density signals Y1, M1, and C1 of yellow, magenta, and cyan are color-processed by the masking circuit 40, and then undercolor removal (UCR) is performed.
A new image density signal Y36 for yellow, magenta, cyan, and black after color processing by the black generation circuit 41,
Convert to M36, C36, K36. Gamma correction circuit 4
2. The image density signals Y37, M37, C37 and K3 which have been gamma-corrected using the gamma correction table shown in FIG.
Reference numeral 7 is a density distribution circuit 43, which is image density signals Kk38, Ck38, Mk3 of dark black ink, dark cyan ink, dark magenta ink and dark yellow ink having high dye density.
8 and Yk38, and image signals Ku38, Cu38, Mu38, and Yu38 of image signals of light black ink, light cyan ink, light magenta ink, and light yellow ink having a low dye concentration. FIG. 8 is a diagram illustrating an example of a light and shade distribution method. The output image density signal may be sequentially calculated based on the input image density signal level, but in order to speed up the processing, it is general to use the density distribution table based on FIG. The density distribution table is set according to the ratio of the dye densities so that the image density signal value and the reflection density value after recording have a proportional relationship. The image signals Kk39 and Kk which are binarized by the binarization circuit 44 and transferred to the eight multi-heads 702 after the light and shade distribution are performed.
u39, Ck39, Cu39, Mk39, Mu39, Y
k39 and Yu39 are generated.

In the image recorded as described above, the image highlight portion is recorded with the light ink to make the ink dots inconspicuous, and the dark portion having a high density is recorded with the light ink and the dark ink. Image quality can be improved compared to the drop method. However, in the light and dark recording method, there are some concerns that printing is performed using dark and light inks of similar colors. For example, when the density distribution as shown in FIG. 8 is performed, the input image density signal level becomes 1
In a region higher than 28, the sum of the output image density signal levels of dark and light is always 255, so that the ink surface density of the dark and light inks of similar colors is equal to that in the case of 100% duty. That is, in contrast to dark-ink recording, the amount of ink consumed in a halftone image is larger than that in the case of using only dark ink. What was a problem in a very high density image area in the case of recording only with ink must be considered in the halftone area in the gradation recording method. However, the problem of ink consumption does not become a big problem considering the cost performance compared with the improvement of image quality, and the problem of ink surface density is also 1
It suffices if the configuration is such that a 00% duty image can be stably recorded, and this does not cause a substantial problem with an inkjet recording apparatus that records only dark ink.

[0008]

However, the most serious problem in the grayscale recording method is that in the image density region of halftone or more recorded with the grayscale ink, the same color is applied to the same pixel depending on the binarization method. When the dark and light ink is recorded, the original image density may not be obtained, or a unique texture may be generated to deteriorate the image quality. In inkjet recording, when another dot is overlaid on the first landed dot, the dot that is hit later than the first landed dot tends to sink in the depth direction of the paper in the overlapping portion. This is a problem that arises. In the case where the dark ink of the same color is landed first as in the above example, when recording with the dark and light ink in a certain image area, the dark ink and the light ink are the same even if the dark and light output image signals are the same. The density of the area where the ratio of landing on the pixel is large is lower than the density of the area where the ratio of the dark and light ink landing on the same pixel is small. That is, since the total amount of dark and light ink landed on a predetermined image area does not change, the degree of density decrease due to the occurrence of a white background where the light ink overlaps the dark ink is greater than the color of the light ink landed on the dark ink. Is also large. If such a phenomenon occurs unevenly in a part of the image area, a thin area will be partially generated in the image area that originally requires uniform image density.
If it continues, it will become a unique texture, and the image will be significantly deteriorated. Even if the dark and light inks overlap with each other at a certain image density, in the case of an image in which the image density changes stepwise, a problem may occur in the continuity of the gradation.

FIG. 9 shows such a situation. Here, in order to simplify the description, an example in which recording is performed only with black dark and light ink is shown. FIG. 9 shows that when an input image density signal of 159/255 level is input to the distribution table,
It shows a state of printing by each head of light and shade when the binarization processing is performed by a simple dither method. Based on the density distribution table of FIG. 8, the output image density signals of 191 levels on the light head side and 64 levels on the dark head side are distributed, and binarized by a simple dither method. Each of the dark and light ink recording pixels is recorded. As shown in FIG. 9, the dark ink head is scanned in such a manner as to precede the light ink head, so that the dark ink first lands on the paper surface to form dots, and then the light ink lands in sequence to form dots. To form. At this time, as described above, when the light ink lands on the dark ink (dots painted in black in FIG. 9), the light ink is fixed so that it sinks below the dark ink. It is not possible to obtain the density increase corresponding to the head density in which the light ink is independently recorded with a slight increase compared with the case of only the dark ink. As a result, in the dot formation on the paper surface shown in FIG.
Only a slightly lower output image density than the originally required output image is obtained, and the gradation reproducibility deteriorates. Similarly, when another well-known method such as the error diffusion method is used as the binarization method, the recording pixel arrangement of each ink has no regularity as shown in FIG. 10, and the overlapping of the dark and light inks varies. In some cases, a density difference locally occurs between the overlapped portion and the non-overlapped portion, and these are connected to each other to cause a specific unevenness in density (texture).

As described above, even in the dark and light recording method in which the high image quality can be realized relatively easily, there is a problem when the dark and light inks overlap due to a factor peculiar to the ink jet recording, and an improvement for realizing the higher image quality is made. Was needed.

Therefore, the present invention has been made in view of the above problems, and provides an ink jet recording apparatus and an ink jet recording method which can obtain high image quality without causing unevenness in light and shade and have a high recording processing speed. To aim.

[0012]

The present invention for achieving the above object is an ink jet recording apparatus for forming an image by ejecting ink onto a recording medium using an ink ejecting means capable of ejecting a plurality of inks having different densities. Therefore, when the input image density signal has a size such that recording is performed using both inks having different densities, the input image density signal is ejected according to the size. A conversion means for converting and outputting the output image density signal for driving the means and the output image density signal for driving the ink ejection means of the other density, and the output image density output from the conversion means. Binarizing means for binarizing the signal, inverting means for inverting the binary data binarized by the binarizing means, binary data inverted by the inverting means and the inverting means And a distribution unit that distributes the binary data before being inverted to the driving data for the ink discharging unit of the one density and the driving data for the ink discharging unit of the other density. .

Further, according to the present invention, there is provided an ink jet recording method for forming an image by ejecting ink onto a recording medium by using an ink ejecting means capable of ejecting a plurality of inks having different densities. Is a size in which recording is performed using both inks having different densities, the input image density signal is output in accordance with the size and the output image density for driving the ink ejecting means of one density is used. Signal and the output image density signal for driving the ink ejection means of the other density, and outputs the converted image. The output image density signal output is binarized, and the binarized binary data is output. And the inverted binary data and the binary data before being inverted are applied to the driving data for the one-density ink discharge means and the other-density ink discharge means. Partitioned between drive data, based on said distributed driving data, ink jet recording method and performing recording by driving the ink ejection means.

Further, according to the present invention, there is provided an ink jet recording method for forming an image by ejecting ink onto a recording medium by using an ink ejecting means capable of ejecting a plurality of inks having different densities. An ink jet recording method, characterized in that, when both inks of the same color having different densities are ejected onto a recording medium for recording, the inks are ejected so that the inks do not overlap the same pixel. Will be provided.

[0015]

According to the present invention, when the ink is ejected onto the recording medium by using the ink ejecting means capable of ejecting a plurality of inks having different densities, the image densities to be recorded are different from each other. When the density is such that both inks of the same color are ejected onto the recording medium for recording, the inks are ejected for recording so that both inks do not overlap the same pixel.

As a result, a high image quality is realized because no local density difference occurs and no peculiar density unevenness (texture) occurs.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a drawing which best represents the features of the present invention, in which R, G, and B luminance signals are changed to C,
7 illustrates an example of a flow of image signal processing for generating binary data to be printed with dark inks of M, Y, and Bk and binary data to be printed with light inks.

In this block diagram, the input gamma correction circuit 1 matches the red image brightness signal R, the green image brightness signal G, and the blue image brightness signal B with the characteristics of the input device, and the cyan image density signal C and the magenta signal. The image density signal M and the yellow image density signal Y are converted.

Color correction (masking) circuit 2, black generation / U
The CR (under color removal) circuit 3 is an input gamma-corrected C,
This is a part that performs color processing for converting the image density signals of M and Y into image density signals of C, M, Y, and Bk in order to match the input image and the output image.

In the table conversion, the circuit 4 is a color-processed C,
This is a part for converting the image density signals of M, Y, and Bk into the image density signals of C, M, Y, and Bk according to the characteristics of the output device (output medium).

The binarization processing circuit 5 converts table-converted multivalued image density signals of C, M, Y and Bk into C, M, Y and B.
This is a part for converting into a binarized signal of k.

The binary data inversion circuit 6 has C, M, Y and Bk.
This is a part for generating a binary signal by inverting the value of the binary signal of.

The binary / inverted binary distribution circuit 7 refers to the color-processed C, M, Y, Bk image density signal values, and if the values are equal to or greater than a predetermined value, binarized C , M, Y, Bk
Of the binary signal and its inverted binary signal are distributed to print data for dark ink and print data for light ink, and if it is less than a predetermined value, binarized C, M, Y, B
The binary signal of k and the binary signal “0” (hereinafter, the binary signal without dot formation is “0”) are distributed to the print data for the dark ink and the print data for the light ink. It is a part.

The table conversion during this processing is to convert the input image density signal level to the output image density signal level as shown in FIG. In this figure, the input image density signal levels 0 to 128 are data conversions for printing with only light ink. The input image density signal levels 129 to 255 are printed using light ink and dark ink. However, the light ink output density signal level and the dark ink output density signal for the respective input signals 129 to 255 are printed. The signal value to which the level is added is always 25
Since it is 5, the binary signal obtained by inverting the binary signal obtained by binarizing the output density signal level of the light ink becomes the binary signal of the dark ink, and vice versa. The inverted signal becomes the light ink binary signal. Therefore, the input density signal levels 129 to 255
, The print data for the dark ink and the print data for the light ink are obtained by performing only the table conversion for the input density signal level of the light ink or the table conversion for the input density signal level of the dark ink as shown in FIG. Can be generated.

The image signal is temporarily stored in the print buffer memory, and is sequentially transferred as an image signal to the recording head in synchronization with the recording scan. In this embodiment, since the dark and light inks of the same color are sequentially printed in the same image area by different printing scans, the print buffer is divided into four areas of different shades of light and a total of eight areas. . Since the print heads are arranged above and below the same print head for shades of similar colors, when sending an image recording signal from the print buffer memory to the print heads, the shade data for each color is combined and transferred. There is. That is, in this embodiment, since the dark and light ink nozzle rows are arranged with four upper and lower nozzles, the image recording signal has a data format in which four dark and light image recording signals are alternately arranged. FIG. 1 shows a block diagram for performing the above-mentioned image data processing and print control.

By carrying out such a processing, the dark ink and the light ink are not imprinted on the same pixel in any binarization method, so that a local density difference does not occur and a specific density is obtained. No unevenness (texture) occurs.

FIG. 11 shows such a state. Here, in order to simplify the description, an example in which recording is performed only with black dark and light ink is shown. FIG. 11 shows a printing state by the heads for each of light and shade when the binarization processing is performed by the simple dither method when the input density signal of 159/255 level is input to the table conversion. Based on the table conversion of FIG. 2, the input density signal for the light head is converted into an output image signal of 191 level. By binarizing this signal by a simple dither method, a binary signal for the light head is generated. Next, this binary signal is inverted 2
A value signal (hereinafter, an inverted binary signal) is generated. And 2
In the value / inversion binary distribution circuit, the original input density signal 159 is compared with the threshold value 128 and the input density signal 15
Since 9 is larger than the threshold value 128, an inverted binary signal is sent to the dark head, so that each dark and light ink recording pixel arrangement shown in FIG. 11 is used for recording. As shown in FIG. 11, since the dark ink head is scanned in such a manner that it precedes the light ink head, the dark ink lands on the paper first to form dots, and then the light ink lands to land the dots. Although formed, the arrangement of the recording pixels of the dark ink that landed first and the arrangement of the recording pixels of the light ink that land later are complementary, so they will not land on the same pixel. Therefore, a uniform image can be obtained on the paper surface.

Similarly, even in the case where dots are recorded at random in the binarization method such as the error diffusion method,
In the input density signal level area where both dark ink and light ink are printed, after binarizing the output density signal for either light ink or dark ink,
Since the inverted value signal is used as the binary signal of the dark ink or the light ink according to the input density signal level, FIG.
As shown in (3), there is no recorded image printed with both dark and light ink in the entire image area, and a uniform image can be obtained.

Further, even when another well-known method is used as the binarization processing method, after binarizing the output density signal of the light ink, the inverted binary signal is input to the light ink. Since the binary signal of dark ink is used according to the density signal level, there are no recording pixels printed with both dark and light ink in the entire image area, and a uniform image without texture can be obtained.

Further, in the switching portion between the area printed with only the light ink and the area printed with the dark ink and the light ink, the dark ink pixel is shifted by one pixel at a predetermined ratio, and the like. The dark ink and the light ink are made to land on the same pixel, and at that time, the dark ink is landed on the same pixel, then the dark ink is landed on the same pixel, and the outline of the dot of the dark ink that is landed afterwards is blurred to form a grain of the dark ink In order to reduce the feeling, or to increase the density in areas where the image density is high, the amount of light ink applied is increased at a predetermined rate without changing the amount of ink applied to dark ink. You may make it land on the same pixel.

(Second Embodiment) In FIG. 13, three kinds of inks having different densities are used, and from the luminance signals of R, G, B, C, M,
Flow of processing for generating binary data to be printed with dark ink having high density of Y and Bk, binary data to be printed with medium density ink (hereinafter referred to as medium ink), and binary data to be printed with light ink with low density Represents an example.

Each part in this figure is "0".
The processing is the same as that shown in FIG. 1 except for the binary / inverted binary distribution circuit 8.

The "0" / binary / inverted binary distribution circuit 8 refers to the color-processed C, M, Y, and Bk image density signal values, and the values are set to 2 depending on a predetermined value range. Valued C,
This is a part for distributing the binary signals of M, Y, Bk, the inverted binary signal and the binary signal “0” to the print data for the dark ink, the print data for the medium ink, and the print data for the light ink.

The table conversion during this processing is to convert the input image density signal level to the output image density signal level as shown in FIG. In this figure, input density signal levels 0 to 85 are data conversions for printing with only light ink. For the input density signal levels 86 to 170, light ink and medium ink are used for printing, but the light ink output density signal level and the medium ink output density signal for the respective input signals 86 to 170 are used. Since the signal value to which the level is added is always 255, the binary signal obtained by inverting the binary signal obtained by binarizing the output density signal level of the light ink becomes the binary signal of the medium ink, and vice versa. A binary signal of light ink is obtained by inverting the binary signal of which the level is binarized. Therefore, for the input density signal levels 86 to 170, only the table conversion for the input density signal level of the light ink or only the table conversion for the input density signal level of the medium ink is performed, whereby the print data for the medium ink and the light ink Print data for and can be generated. For the input density signal levels 171 to 255, printing is performed using medium ink and dark ink.
Since the signal value obtained by adding the output density signal level of the medium ink and the output density signal level of the dark ink to each of the input signals 171 to 255 is always 255, a binary signal obtained by binarizing the output density signal level of the medium ink. Is the binary signal of the dark ink, and vice versa is the binary signal of the medium ink that is the inverse of the binary signal obtained by binarizing the output density signal level of the dark ink. Therefore, for the input density signal levels 171 to 255, only the table conversion for the input density signal level of the medium ink or only the table conversion for the input density signal level of the dark ink is performed, whereby the print data for the dark ink and the medium ink are obtained. Print data for and can be generated.

By carrying out such processing, light ink, medium ink, and dark ink are not ejected to the same pixel in any binarization method, so that a local density difference does not occur and it is peculiar. The density unevenness (texture) does not occur.

In this figure, the input density signal level of 0
To 85, output image signals for light ink are generated, for 86 to 170, output image signals for medium ink are generated, and for 171 to 255, output image signals for dark ink are generated. However, the conversion may be performed for either ink in each input image signal range.

The "0" / binary / inverted binary distribution circuit 8 is shown in FIG.
4, the input density signals 0 to 85 are light ink output density signals, 86 to 170 are medium ink output density signals, and 171 to 255 are dark ink output density signals. When a conversion table for converting the input signals to the input signals 0 to 85 is used, a binary signal for light ink print data, “0” for medium ink print data, and “0” for dark ink print data. For each of the print heads 86 to 170, an inverted binary signal as light ink print data, a binary signal as medium ink print data, and a “0” as dark ink print data are sent to each print head. Send, 171-25
For No. 5, "0" is sent to the print heads as light ink print data, an inverted binary signal as medium ink print data, and a binary signal as dark ink print data.

(Third Embodiment) In FIG. 15, in order not to overlap the same color ink on the same pixel of the present invention, the landing positions of the dark and light inks of the respective colors are made highly accurate, so that the dark and light of the same head are changed. Ink jet recording apparatus and recording pixel arrangement in an ink jet recording apparatus configured to eject ink and to perform recording scanning by arranging four color density heads of black, cyan, magenta, and yellow in parallel for color printing And schematically showing dot formation on the paper surface,
The state of printing will be described.

FIG. 16 is an explanatory diagram of the structure of a recording head for ejecting dark and light ink. One end of the wiring board 200 is mutually connected to the wiring portion of the heater board 100, and the other end of the wiring board 200 corresponds to each electric / thermal energy converter for receiving an electric signal from the recording apparatus main body. A plurality of pads are provided.
As a result, the electric signal from the recording apparatus main body is supplied to each electric / thermal energy converter. Metal support 3 that supports the back surface of the wiring board 200 on a flat surface
00 is the bottom plate of the inkjet unit. The pressing spring 500 is a claw that is hooked by using a portion formed by bending a groove having a substantially U-shaped cross section and an escape hole provided in the base plate to elastically press a region near the ink ejection port of the groove top 1310 on a line. The base plate has a pair of rear legs that receive the force acting on the spring. Due to this spring force, the wiring board 200 is attached by pressure contact with the groove top 1310. The wiring board 200 is attached to the support by sticking 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
A channel 1500 formed by molding, and the groove 1310 also leads to the orifice plate portion 1300 and each ink supply port.
Are integrally formed. 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 can be 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 ink supply member 600 is sealed, and the gap between the orifice plate portion 1300 and the front end portion of the support substrate 300 is completely sealed by passing through the groove 310 formed in the support substrate 300. Stop.

FIG. 17 is a perspective view of the groove top 1310 of the recording head used in this embodiment as seen from the heater board 100 side. A plurality of liquid chambers are provided, and each liquid chamber has a groove 30 on the pressure contact surface of the wall 10 with the heater board 100.
Is provided. This groove communicates with the outer peripheral portion of the groove top 1310. After the groove heaven 1310 is pressed against and closely attached to the heater board, 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 separating the liquid chamber into a plurality of chambers in this way, different inks can be ejected to the respective ink ejection ports, and therefore, in the present embodiment, dark and light inks are ejected from the same head. As mentioned above,
In the present embodiment, the mutual precision of landing between the dark and light inks of similar colors, which is particularly important, is improved.

FIG. 18 shows the structure of a four-head integrated ink jet cartridge in which the above-mentioned four heads capable of ejecting four dark and light inks of K, C, M, and Y respectively are integrally assembled in a frame 3000. . The four recording heads are mounted in the frame 3000 at predetermined intervals, and the resists in the nozzle array direction are also fixed in an adjusted state. In this embodiment, the mechanical reference surface of the head is used for adjustment to improve the mutual landing position accuracy between colors.However, after temporarily fixing the recording head to the frame, the recording head is actually ejected to set the landing position. The mutual impact positions between the colors may be directly adjusted based on the measured data to further improve the accuracy. 3100 is a cover for the frame, 3200 is 4
It is a connector for connecting a pad provided on the wiring board 200 of one recording head and an electric signal from the recording apparatus main body. Assembling the four heads together is effective in improving the mutual landing position accuracy between the heads as described above, in addition to the handling advantage, but the effect that the mutual positioning between the heads is unnecessary. It also has a great effect in that the number of signal line connections with the recording apparatus main body can be reduced. For example, the signal line common to the four heads such as the GND line can be made common to reduce the number of lines as it is,
If an integrated circuit board is provided and time-division driving is performed for each head, the recording signal line can be shared.
Such a reduction in the number of electrical connections is effective in an apparatus having a large number of signal lines such as a color machine or a multi-nozzle high speed machine, and is a very effective means particularly in the dark and light inkjet recording apparatus of the present invention.

FIG. 19 shows a state in which the above-described four-head integrated ink jet cartridge 222 is mounted on a carriage for recording and scanning. Ink tank 1
18 is divided into upper and lower chambers by a partition 230,
The upper room is filled with light ink and the lower room is filled with dark ink. Four dark and light ink tanks of four colors are combined with the ink jet cartridge 222 on the carriage to form liquid chambers separated into two. Connect and supply ink. As described above, in the present embodiment, recording is performed by using an integrated recording head having a total of eight liquid chambers and nozzle rows corresponding to the four color ink tanks, which are integrated with four color ink tanks filled with dark and light inks. As a result, the inconvenience in handling associated with the grayscale recording is eliminated.

The ink jet recording apparatus to which this embodiment can be applied has a main part structure shown in FIG. In this figure, the carriage 706 has four ink tanks filled with four dark and light inks of four colors, black, cyan, magenta, and yellow, and four color inks are ejected by the upper and lower nozzle rows, respectively. The above-mentioned head 702 in which the four heads are integrated is mounted. The basic operation of the ink jet printer in this embodiment is the same as that of the members having the same numbers as those of the printer described in the conventional example.
The operation is performed, which will be described again here. Reference numeral 703 denotes a paper feed roller, and printing paper 707 together with an auxiliary roller 704.
While holding down, the printing paper 707 is rotated in the direction of the arrow in FIG. Further, reference numeral 705 denotes a paper feed roller which feeds the printing paper and also plays a role of suppressing the printing paper 707 similarly to 703 and 704. Carriage 7
No. 06 stands by at the home position (h) at the position shown by the dotted line in the figure when printing is not performed or when multihead 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 along the carriage guide shaft 708 when a print start command arrives, based on the read signal from the linear encoder 709. By ejecting the inks of four shades of light and shade of four colors in accordance with the recording signals from four nozzle rows above and below each color on the multi-head 702 at a timing, printing is performed for each shade of four pixels.

When the data printing is completed up to the end of the paper surface, the carriage returns to the original home position and printing is performed again in the x 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 of 4 pixels. In this way, by printing and feeding the paper for each of the light and shade of 4 pixels for each scan of the carriage, the data printing on one paper surface is completed.

Even in the case of such a configuration, when the conventional image signal processing shown in FIG.
2 even when binarized by the simple dither method of FIG.
Even when binarized by the error diffusion method of No. 2, dark and light ink may be printed on the same pixel in an overlapping manner.

However, by performing the image signal processing of the present invention, as shown in FIG. 15 and FIG.
Even if the binarization method is used, the dark and light inks do not overlap the same pixel, and the landing positions of the recording dots of the dark and light inks of the same color can be made highly accurate.

The present invention brings excellent effects particularly in an ink jet type recording head and a recording apparatus which form flying droplets by utilizing thermal energy among the ink jet recording systems.

Regarding the typical structure and principle thereof, 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 discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective 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.

Further, as a full line type recording head having a length corresponding to the width of the maximum recording medium which can be recorded by the recording apparatus, the length can be increased by combining a plurality of recording heads as disclosed in the above-mentioned specification. The present invention can exert the above-mentioned effects more effectively, although it may have a configuration that satisfies the above requirement or a configuration as one recording head integrally formed.

In addition, by being mounted on 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. 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 evaporation of the ink. In some cases, such as ink that is liquefied by applying heat energy according to a recording signal and ejected as a liquid ink, or one that has already started to solidify when it reaches a recording medium. The use of an ink having a property of being liquefied only by heat energy is also applicable to the present invention. In such a case, the ink is Japanese Patent Laid-Open No. 54-5684.
No. 7 or JP-A-60-71260, a mode in which the porous sheet is opposed to the electrothermal converter in the state of being held as a liquid or solid in the recess or through hole of the porous sheet. May be 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 device such as a word processor or a computer, 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. 24 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, 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,
Item input, coordinate position input, and the like on the display unit 1202 can be performed.

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 conveying 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 retransmits 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 storage device 1212 uses a floppy disk, a hard disk, or the like as a storage medium. The external storage device 1212 stores character information, music or voice information, a user application program, and the like.

FIG. 25 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 through 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, 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. 24, 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 device, the facsimile information input from the facsimile transmission / reception unit 1208 via the communication line is received by the control unit 1201 according to a predetermined program, and output to the printer unit 1206 as a received image.

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 transmission processing according to a predetermined program by 201, it is transmitted to the communication line via the facsimile transmission / reception unit 1208. Note that the above-described information transmission may be an integrated type in which an ink jet printer is built in the main body as shown in FIG. 26, and in this case, it becomes possible to enhance the portability. In the figure, parts having the same functions as those in FIG. 25 are designated by the corresponding reference numerals.

[0070]

As described in detail above, according to the present invention,
When an image is formed by ejecting ink onto a recording medium using an ink ejecting unit capable of ejecting a plurality of inks having different densities, both the same color inks having different image densities to be recorded are recorded on the recording medium. When the density is such that the two inks are discharged onto the same pixel for recording, the inks are discharged so that the two inks do not overlap the same pixel, and the recording is performed, so there is no local density difference and there is a specific unevenness in density (texture). Is reduced and high image quality is realized.

Further, when the binary data for driving the ink ejecting means is obtained based on the input image density signal, the input image density signal is used as the output image density signal for driving the ink ejecting means of one density. By converting one of the output image density signals for driving the ink ejecting means of the other density and binarizing it, the time for the binarization processing is shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of image signal processing.

FIG. 2 is a diagram showing input image density signals of C, M, Y, and Bk as Cu,
It is a table for converting to output image density signals of Mu, Yu, and Bku.

FIG. 3 is a diagram showing input image density signals of C, M, Y, and Bk as Cu,
It is a table for converting to output image density signals of Mu, Yu, and Bku.

FIG. 4 is a main part configuration diagram of a conventional color ink jet recording apparatus of a serial print type using dark and light ink.

FIG. 5 is a diagram of a multi-nozzle when the multi-head is viewed from the paper surface side.

FIG. 6 is a diagram showing a flow of image signal processing.

FIG. 7 is a γ correction table for converting an input density signal into an output density signal.

FIG. 8 shows input image density signals of C, M, Y and Bk as Ck,
It is a table for distributing output image density signals of Cu, Mk, Mu, Yk, Yu, Bkk, and Bku.

FIG. 9 is a diagram showing a printing state by conventional image signal processing.

FIG. 10 is a diagram showing a printing state by conventional image signal processing.

FIG. 11 is a diagram showing a printing state by the image signal processing of the present invention.

FIG. 12 is a diagram showing a printing state by the image signal processing of the present invention.

FIG. 13 is a diagram showing a flow of image signal processing shown in the second embodiment.

FIG. 14 shows C, M, Y, and Bk input image density signals as C
k, Cc, Cu, Mk, Mc, Mu, Yk, Yc, Y
u, Bkk, Bkc, Bku A table for converting into an output image density signal of any one of dark, medium, and light ink.

FIG. 15 is a diagram showing a printing state of the configuration shown in Example 3;

FIG. 16 is an explanatory diagram of a configuration of a head unit used in this embodiment.

FIG. 17 is a groove 13 of the head unit used in this embodiment.
It is the perspective view which looked at 00 from the heater board 100 side.

FIG. 18 is a configuration diagram of a four-color integrated head unit used in this embodiment.

FIG. 19 is an explanatory diagram in which an inkjet cartridge and an ink tank are mounted on a carriage.

FIG. 20 is a schematic explanatory diagram of an inkjet recording apparatus to which Example 3 is applied.

FIG. 21 is a diagram showing a printing state in the conventional image signal processing in the third embodiment.

FIG. 22 is a diagram showing a printing state in the conventional image signal processing in the third embodiment.

FIG. 23 is a diagram showing a printing state in the image signal processing of the invention in the third embodiment.

FIG. 24 is a block diagram showing a schematic configuration when the inkjet recording apparatus of the present invention is applied to an information processing apparatus.

FIG. 25 is an external view of an information processing device.

FIG. 26 is an external view showing another example of the information processing apparatus.

[Explanation of symbols]

 4 table conversion circuit 5 binarization processing circuit 6 binary data inversion circuit 7 binary / inverted binary distribution circuit 8 “0” / binary / inverted binary distribution circuit 702 recording head

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location 9012-2C B41J 3/04 103 B (72) Inventor Hiromitsu Hirabayashi 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 within Canon Inc. (72) Inventor Hitoshi Sugimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Miyuki Matsubara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (11)

[Claims] 1. An ink jet recording apparatus for forming an image by ejecting ink onto a recording medium by using an ink ejecting means capable of ejecting a plurality of inks having different densities, wherein the magnitude of an input image density signal is Is a size in which recording is performed using both different inks, the input image density signal is output in accordance with the size and the output image density signal for driving the ink ejection unit of one density and the other A conversion unit for converting and outputting one of the output image density signals for driving the density ink ejection unit; a binarization unit for binarizing the output image density signal output from the conversion unit; The inverting means for inverting the binary data binarized by the binarizing means, the binary data inverted by the inverting means and the binary data before being inverted by the inverting means An ink jet recording apparatus characterized by comprising: a distribution means for distributing to the driving data for ink ejection means with the driving data the other concentration on the ink discharge unit of time. 2. The ink ejected by the ink ejecting means is an ink having a plurality of colors and different in density for each color, and the ink ejecting means corresponds to each ink. Inkjet recording device. 3. The ink ejecting means is means for ejecting ink by utilizing thermal energy, and is provided with a thermal energy converter for generating thermal energy applied to the ink. Inkjet recording device. 4. The ink ejecting means causes the ink to undergo 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. The inkjet recording device described. 5. An image forming apparatus comprising the ink jet recording apparatus according to claim 1 and a document image reading unit. 6. An image forming apparatus comprising the inkjet recording apparatus according to claim 1 and a transmission and / or reception unit for image information. 7. The image forming apparatus according to claim 6, further comprising a document image reading unit. 8. An image forming apparatus comprising the inkjet recording apparatus according to claim 1 and a recording signal input unit. 9. The image forming apparatus according to claim 8, wherein the recording signal input means is a keyboard. 10. An ink jet recording method for forming an image by ejecting ink onto a recording medium using an ink ejecting means capable of ejecting a plurality of inks having different densities, wherein the magnitude of an input image density signal is a density. Is a size in which recording is performed using both different inks, the input image density signal is output in accordance with the size and the output image density signal for driving the ink ejection unit of one density and the other The output image density signal for converting the density of the output image density signal for driving the ink ejecting means is output, the output image density signal output is binarized, and the binarized binary data is inverted. The inverted binary data and the uninverted binary data are used as drive data for the one density ink ejection unit and for the other density ink ejection unit. Ink jet recording method and distribution, based on said distributed driving data, and performing recording by driving the ink ejection means. 11. A recorded matter obtained by carrying out the inkjet recording method according to claim 10.