JPH08336979A - Color ink-jet recording device and recording method using the same - Google Patents

Abstract

PURPOSE: To control bleeding and to conduct higher speed recording by making the number of nozzles of a recording head for ink of a slow fixing type or ink necessary to be discharged at a low frequency greater than that for ink of other types. CONSTITUTION: In a head, a black ink and cyan, magenta, yellow inks which have different values of surface tension are placed in an ink tank, and color recording is conducted on a recording sheet. For the first line, printing is carried out using only C, M, Y, and after the sheet being fed for one line, black printing is conducted on a color printing part of the previous line using nozzles 1B-NB of a Bk head. At the same time, Y, M, C are used for printing on the second line. This kind of printing method is repeated to obtain a color print of an A4 size. The obtained print is free from bleeding in the boundary part of colors and has good picture quality in a black character part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink jet recording apparatus and a recording method therefor, and more particularly, to a serial type color printer, which comprises a recording head for ejecting a plurality of colors of ink, including black, for color recording Regarding the method.

[0002]

2. Description of the Related Art Conventionally, a serial type color ink jet printer generally has an apparatus as shown in FIG. 1 in which four color heads of yellow, magenta, cyan and black are arranged in a row. In such a conventional type, as shown in FIG. 1, the heads are arranged in a row in the scanning direction of the head, and the third head is arranged.
As shown in (a) of the figure, the heads of the respective colors have the same size and the same number of nozzles. By the way, JP-A-61
No. 104856, as shown in FIG. 3 (b), in an inkjet head for a color printer, the number of black nozzles is set to be larger than the number of yellow, magenta, and cyan nozzles so that only black characters are printed. At times, it provides a head for a printer that can suppress the decrease in recording speed and can sufficiently output color recording. Also, according to this, the nozzle pitch between the color nozzle and the black nozzle is changed, and the quality of the color and black characters is improved by making the ink preparation amount the same when outputting a color image and when outputting a black character. are doing.

[0003]

However, in the above-mentioned conventional example, high-quality color printing can be performed without problems when printing on coated paper which is a special paper for ink jet, but general office paper and PPC When color recording is performed on so-called plain paper such as paper, the following problems occur. That is, when an ink having a poor fixability of ink (the ink liquid on the paper is completely absorbed in the paper and becomes an apparent dry state) is used, (1) Ink bleeding (so-called bleeding) occurs at the boundary portion. (2) If the printed surface is rubbed immediately after printing, stains may occur,
Further, when an ink having a fast ink fixing property is used, bleeding does not occur, but a sufficient recording density cannot be obtained, and the print quality of a black character portion is conspicuously deteriorated. There was a problem. That is, it is difficult for the conventional one to achieve both color bleeding and print quality of black characters in particular. Further, in order to solve the above-mentioned problems, conventionally, at the time of color recording, printing dots of each color are thinned to reduce the amount of ink charged, thereby covering poor fixability and suppressing bleeding, or For example, the printing time is lengthened by thinning out to 1/2 and scanning one line twice, and fixing time is increased.
However, with such a method, the printing speed becomes extremely slow, which is impractical. As a method for solving such a problem, an ink having a fast fixing property and a good print quality may be used, but such an ink has not been developed yet.

On the other hand, in a color ink jet recording apparatus for performing color recording by ejecting a plurality of kinds of ink as described above, there is a problem that the scanning speed of the carriage is determined by the head of the color tone having the lowest ejection frequency. Have In other words, in such color recording, the inks of each color tone have different viscosities and droplet ejection volumes, so the ejection frequencies of these heads differ greatly, resulting in a decrease in recording speed. To further explain this point, in color recording in bubble jet recording, a liquid jet recording head for ejecting ink of different color tones is integrated, and plural kinds of ink are ejected simultaneously by one scanning of the carriage. Performing recording has the advantages that high-speed recording is possible, registration is easy, and the recording apparatus can be downsized. For example, in a printer that prints one line with 64 nozzles,
As shown in (a), a head having 64 nozzles for each color is integrated to eject ink of each color tone according to a recording signal in one movement of the carriage in the sub-scanning direction, and then to feed one line of paper. It is also possible to mention a means for performing the above and again performing recording in the same manner. In the recording method, nozzles for ejecting ink of each color tone are arranged in parallel to the sub-scanning direction as shown in FIG. 4A, and ink is sequentially ejected according to a recording signal. As another color recording means, as shown in FIG. 4B, nozzles for ejecting ink of each color tone are arranged so as to be displaced by 64 nozzles each.
Different lines are printed with each color ink by scanning the carriage in the sub-scanning direction one time, and then the paper is fed by 64 nozzles for printing. For example, when printing with four color inks, 4 Means for forming one pixel by scanning the carriage a number of times can also be mentioned. In the recording method, for example, when it takes a long time to dry the ink, it is possible to prevent the bleeding of the inks because it is possible to secure the time interval for the inks of different tones to be ejected for one carriage scanning time. have. However, when color recording is performed by integrating a liquid jet recording head that ejects a plurality of types of ink in this way, the scanning speed of the carriage is determined by the head of the color tone with the slowest ejection frequency, and the ink of each color tone has a viscosity. Since the droplet ejection volumes are different, the ejection frequencies of the heads are greatly different, and as a result, the recording speed is reduced by the head having the color tone having the slowest ejection frequency among them.

Therefore, the present invention solves the above problems and provides a color ink jet recording apparatus and a recording method therefor capable of suppressing bleeding, recording with excellent print quality of black characters, and recording at higher speed. The purpose is to do.

[0006]

In order to solve the above-mentioned problems, the present invention is directed to a color ink jet recording apparatus for ejecting a plurality of colors of ink to perform color recording. By increasing the number of nozzles of the recording head for ink that requires ink ejection at a low frequency due to the drop ejection volume, etc., to more than the number of nozzles of the recording head that ejects other inks, it is possible to suppress bleeding and achieve good printing quality. The inkjet recording apparatus is configured. One of the features of the present invention is
The number of nozzles of a recording head that ejects a black ink, which has a fixing property slower than that of a color other than black, is twice the number of nozzles of a recording head that ejects a color other than black. By the control, during color recording, black ink is printed before or after one scan for printing a color other than black by ½ of the total number of nozzles of the recording head that ejects the black ink. In the case of recording only with black ink, the printing is performed by the total number of nozzles of the recording head of the black ink to suppress bleeding, and in particular, color ink jet recording with good print quality of black characters is realized. Further, in the color ink jet recording method using the apparatus of the present invention, the surface tension of the black ink is 40 dyn / cm or more, and the surface tension of the inks of colors other than black is 40 dyn / c.
Better results can be achieved by using inks that are less than m 2. Further, another one of the features of the present invention is that as a recording method, the number of nozzles that eject high-viscosity ink or the number of nozzles of a recording head that eject ink with a large droplet ejection volume is low-viscosity ink. It is an integral multiple of the number of ejection nozzles or the number of nozzles of a recording head that ejects ink with a small droplet ejection volume, and after thinning recording by the nozzles, the thinned gap is filled by scanning the carriage multiple times. By recording on the color recording medium, it is possible to realize color ink jet recording capable of printing without reducing the recording speed.
In this case, a better result can be achieved by setting the droplet ejection volume of the black ink to about twice as large as the droplet ejection volume of the ink of a color other than black.

[0007]

According to the present invention, with the above structure, for example, black (hereinafter referred to as Bk), which is slower than the fixability of inks of yellow, magenta, and cyan (hereinafter referred to as Y, M, and C), is used.
When performing color recording with the inks of Y, M,
By using 1/2 of the nozzles of Bk (N nozzles) which is twice the number of nozzles (N nozzles) at a position different from the nozzle position of the C head, Y, M,
Bk is printed before or after scanning one line for printing C,
When only black characters are printed, the total number of nozzles of the Bk head (2 × N) is used for printing. In the present invention, this covers the poor fixing property of the black ink and suppresses color bleeding,
Not only can the printing quality of the black character portion be kept good, but the printing speed when printing only the black character can be doubled. Furthermore, in order to improve the printing quality of the black character portion, when double-scanning Bk ink is performed in two scans, the apparatus of the present invention performs one scan with N nozzles of Bk ink, By sharing the second scan with the subsequent N lines, it is possible to improve the printing quality of the black character portion without lowering the printing speed. In such an apparatus of the present invention, as shown in FIG. 1, four-color heads having a plurality of nozzles arranged at right angles to the scanning direction of the inkjet head are provided in a row in the scanning direction. As shown in FIGS. 2A and 2B, when the number of nozzles of the Y, M, and C heads is N, the number of nozzles of the Bk recording head is 2 × N. Is configured to be. As the ink used in the present invention, it is preferable that the surface tension of black ink is 40 dyn / or more and the surface tension of other color inks is less than 40 dyn / cm 2. The inkjet head used in the present invention is a multi-nozzle type on-demand head, an electrostatic suction type head, or a continuous type head, in particular, a piezo type, and an on-demand type ink jet using heat. A head is preferred.

Further, the present inventors repeated a number of experiments at 360 DPI for plain paper color recording using four color inks of Y, M, C, and Bk, and as a result, Y 40 pl (picoliter), M,
It was found that the best results can be obtained from both concentration and bleeding when C is 50 pl and Bk is about 80 pl. In the first place, among the inkjet methods, there is a bubble jet method as a method suitable for high-density multiple nozzles. However, in this bubble jet method, the ejection frequency greatly depends on the refill time of the ink. The refill time is the time required for the ink droplets to be ejected and the meniscus to recede, and to return to the meniscus position before ejection again. This refill time greatly changes depending on the viscosity of the ink and the size of the ejected droplet. That is, when inks having different color tones are prepared and the viscosities of these inks are different, when the optimum ink formulation is prepared by the above-mentioned droplet ejection volume, when the viscosities of the respective colors are different, and further, the face amount dispersion type ink is used. The refill time for each color is different when combined with or with a phase change type solid ink.
Further, even when the ink having the extremely similar formulation as described above is used, the Bk ink needs to have a droplet ejection volume which is about twice that of the Y ink and the M and C inks, and the refill time of the Bk ink is different. It takes longer than the refill time for inks of other colors. The recording speed in the bubble jet recording method is determined by the ejection frequency of ink when the number of ejecting nozzles is the same, and the main factor affecting the ejection frequency is the refill time. That is, as the refill time is shorter, ink can be ejected at a higher frequency, and high-speed recording can be performed.

As one of the concrete modes of the present invention, for example, there is a liquid jet recording head shown in FIG. In FIG. 5A, a liquid jet recording head having 128 nozzles for ejecting Bk ink, Y, M, and
Color recording is performed by using a liquid jet recording head having 64 nozzles for respectively ejecting C ink and a head in which a total of 4 heads are integrally fixed. As described above, in a similar ink formulation, the volume of Bk ink droplets is 80 pl and Y (40 pl), M and C (50 p).
The volume of the ink Bk is about twice as large as that of the color inks such as l), and thus the ejection frequency of Bk is about 2/3 of the color ink. Therefore, when the number of nozzles ejecting ink of each color tone is the same as 64 nozzles, the recording speed is determined by the Bk ink having the lowest ejection frequency. In the present invention, as shown in FIG.
In order to compensate for the decrease in the ejection frequency of the Bk nozzle, the number of Bk nozzles is twice the number of color inks. In the liquid jet recording head, Bk ink is one of color inks.
Driving is performed at a driving frequency of / 2, and printing is performed by thinning out every other dot. At this time, the color ink is driven by a driving frequency that is twice Bk and printing is performed without thinning. Next, the paper is fed by 64 nozzles (for the number of nozzles of color ink), and the recording of the next line is performed. In Bk, since printing is performed by thinning out, B of the next 64 nozzles
The ejection is performed so as to interpolate between the dots thinned by the k nozzle. When color recording is not performed,
Recording may be performed using all nozzles that eject Bk ink. The ejection frequency at this time may be recorded at the highest ejection frequency that can eject Bk ink. In the example shown in FIG. 5A, it is desirable to use 128 nozzles and perform printing in two lines at once. By performing printing in this manner, it is possible to prevent a decrease in recording speed during color recording due to a low ejection frequency of Bk. In the above example, the means for increasing the Bk droplet ejection volume to increase the Bk recording density and preventing the decrease in the recording speed due to the decrease in the ejection frequency due to the increase has been described. Of course, the present invention is not limited to the Bk color tone described above, and these concepts may be applied to Y, M, and C inks, and any color tone ink such as red and blue inks. . Further, the number of nozzles may be changed to cope with not only the difference in droplet ejection volume but also the difference in ejection frequency due to the difference in ink viscosity or the like. For example, when a face amount dispersion type ink is used as the Bk ink, it can be applied to a difference in ejection frequency caused by adding a polymer compound or the like to increase ink viscosity in order to suppress ink bleeding.

As a further effective use example of the present invention, as shown in FIG. 5B, a liquid jet recording head capable of ejecting inks of plural kinds of color tones from one liquid jet recording head. The case where it applies is mentioned. Such a liquid jet recording head capable of ejecting inks of a plurality of color tones from a single chip can achieve high density of ink ejection nozzles, reduce cost, and downsize the device. Have the advantages of. The electrothermal conversion element of a general liquid jet recording head, a control element for applying an electric signal to the element, and the like are most preferably manufactured by a semiconductor manufacturing process using a silicon substrate. For this reason, how to reduce the substrate area of one head and increase the number of samples taken from one wafer is a point to reduce the cost. This means how to install a component that supplies inks of a plurality of colors to a chip (substrate on which an electrothermal conversion element is formed) of a small area and to attach a recovery member such as capping or pumping. It is related to the mounting technology. More importantly, how many nozzles of each color are distributed also has an important influence on the head cost and the apparatus cost. In other words, it is considered most common to evenly distribute the number of nozzles that eject ink of each color tone of Y, M, C, and Bk.
Japanese Patent Laid-Open Publication discloses a liquid jet recording head of this form. However, it is often not optimal to set the same number of nozzles that eject ink of each of these color tones. That is, it can be easily assumed that the printer is most often used to print characters using Bk ink, and that the color is used less frequently than Bk ink. Therefore, it is desirable to perform the recording with the Bk ink at an extremely high speed, and there is a demand that a relatively long time is required for the color recording. Of course, color recording may be performed at a high speed, but this leads to an increase in the capacity of the power supply, an increase in the speed of signal processing, and an increase in the price of the head, resulting in an expensive recording apparatus. If such an increase in price is incurred, it is often more preferable to reduce the performance during color recording and set the price low. For this purpose, the number of nozzles for ejecting Bk ink is set to be larger than the number of nozzles for ejecting color ink, printing is performed at high speed in character printing, and at a slightly low speed in color recording. It becomes preferable to print.

In FIG. 5 (b), the nozzle array shown in FIG. 5 (b) is collectively formed on the substrate. The recording method can be recorded by the above-mentioned means. In FIG. 5B, the ink tanks 1 (a) to (d) are formed by four divided compartments filled with Bk, Y, M, and C inks, and the ink is 3 ′ from these ink tanks. It is guided to the chip on which the electrothermal conversion element is formed by the ink flow path jig shown in FIG. The chip 5 on which the electrothermal conversion element is formed is fixed to the tank by a 4'chip mounting jig. The chip 5 has the ink ejection hole array shown in FIG. In FIG. 5C, the ink nozzle row groups for ejecting ink of each color tone are arranged on both sides with respect to the through holes for ink supply formed in the substrate, so that one color nozzle row group has two rows. Nozzle row. The nozzle rows may be arranged in a staggered pattern or may be arranged in parallel. In the case of the staggered arrangement, when the nozzle density of each row is formed at 160 dpi, the nozzle density of the liquid jet recording head is 360 dpi as a whole, and the manufacturing is easy.
When arranged in parallel with each other, for example, each row 360d
If it is formed by pi, double speed recording can be performed. The printing can be performed by thinning out the printing of each nozzle row and filling the gaps thinned by the preceding nozzle row and printed by the nozzle rows that follow. Furthermore, a small droplet is ejected to form a plurality of ink droplets to
When the liquid jet recording head is used for multi-valued recording that constitutes a pixel, it is also possible to eject ink from each nozzle row so as to strike the same pixel. In this recording method, it is possible to develop three kinds of recording densities when ink is not ejected, when one ink is ejected, and when two ink is ejected. It can be carried out. It is possible to further increase the multi-valued number if each nozzle performs a plurality of recordings for one pixel. In such multi-value recording, it is necessary to make the ink droplet ejection amount smaller than the above-mentioned amount, and it is preferable to optimize the droplet amount respectively.

The liquid jet recording head shown in FIG.
It shows an example in which one nozzle row is distributed to four colors.
In FIG. 5D, a chip 6 having an electrothermal conversion element is mounted on an ink tank 1 filled with inks of four kinds of color tones. In the chip 6, an ink flow path for guiding each ink to the electrothermal conversion element is formed inside. The arrangement of the nozzles is 6 as shown in FIG.
A nozzle group that ejects Bk ink of 4 nozzles and a nozzle group that ejects Y, M, and C inks of 24 nozzles each are arranged in one row. Each nozzle group is spaced by 16 nozzles to prevent ink mixing. Character recording with Bk ink is performed with 64 nozzles.
Recording is performed by using 24 nozzles out of 24 nozzles of M and C and 64 nozzles of Bk, and after performing one scan of the carriage, paper feeding for 24 nozzles is performed to perform recording. . Of course, the number and arrangement of these nozzles may be variously selected according to the performance realized by the recording apparatus.

In FIG. 5D, the number of nozzles that eject Bk ink is 64, and the number of nozzles that eject color ink is 24. The recording apparatus has at least two kinds of modes, that is, a character recording mode (a mode for recording only with Bk ink) and a color recording mode (a mode for recording with Bk, Y, M, C inks). It is automatically changed according to the recording signal. That is, there is a mechanism for performing the recording in the character recording mode when only the character recording is performed and automatically changing to the color recording mode when the color recording area exists. In the color recording mode, the number of nozzles for ejecting Bk ink is also twice that of 24, and the paper feed is changed to the feed pitch corresponding to the recording of 24 nozzles. As the nozzles for ejecting Bk ink, a total of 48 nozzles, which is 24 nozzles adjacent to the nozzles for ejecting color ink and 16 nozzles apart from the color ink nozzle group, are used. As described above, the ejection frequency of the Bk ink is 1/2 of the ejection frequency of the color ink, and the preceding 24 nozzles (a nozzle group facing the recording paper first) thins out one dot at a time to perform Bk recording. Then, recording is performed so as to fill the gap thinned by another 24 nozzles. By adopting such a configuration, even if the ejection frequency of the Bk ink is ½ of the ejection frequency of the color ink, it is possible to minimize the decrease in the recording speed in the color recording mode. . Of course, the concept of the present invention described above may be applied to the distribution of inks of various color tones and the number of nozzles. That is, B
If the ejection frequency of the k ink is much slower than the ejection frequency of the color ink (1/3 or less), the number of nozzles used for recording the Bk ink may be set to three times the number of nozzles used for ejecting the color ink. I do not care. Further, when the ejection frequency of the color ink is lower than the ejection frequency of the Bk ink, the number of nozzles ejecting the color ink may be increased.

FIG. 10 is an external perspective view showing an example of an ink jet recording apparatus (IJRA) in which the liquid jet recording head obtained by the present invention is mounted as an ink jet cartridge (IJC). In the figure, reference numeral 20 is an ink jet cartridge (IJC) provided with a nozzle group for ejecting ink facing a recording surface of a recording paper fed onto a platen 24. Reference numeral 16 is a carriage HC that holds the IJC 20, and is connected to a part of the drive belt 18 that transmits the driving force of the drive motor 17, and can slide with two guide shafts 19A and 19B that are arranged in parallel with each other. By doing so, the reciprocating movement over the entire width of the recording paper of the IJC 20 becomes possible. A head recovery device 26 is arranged at one end of the movement path of the IJC 20, for example, at a position facing the home position. The head recovery device 2 is driven by the driving force of the motor 22 via the transmission mechanism 23.
6 is operated and the IJC 20 is capped. IJC by the cap portion 26A of the head recovery device 26
Head recovery device 2 in connection with capping to 20
Ink is sucked by an appropriate suction means provided in 6 or ink is pressure-fed by an appropriate pressurizing means provided in the ink supply path to the IJC 20, and the ink is forcibly discharged from the ejection hole to increase the inside of the nozzle. Ejection recovery processing such as removing viscous ink is performed. Also, the IJC 20 is protected by capping at the end of recording or the like. Three
Reference numeral 0 denotes a blade as a wiping member which is disposed on the side surface of the head recovery device 26 and is made of silicon rubber. The blade 30 is held by the blade holding member 30A in the form of a cantilever, and is operated by the motor 22 and the transmission mechanism 23 as in the head recovery device 26.
It is possible to engage with the discharge surface of 0. As a result, IJC
The blade 30 is projected into the movement path of the IJC 20 at an appropriate timing in the recording operation of 20 or after the ejection recovery process using the head recovery device 26, and the IJC 2
Dew condensation, wetting, dust, or the like on the ejection surface of the IJC 20 is wiped with the movement operation of 0.

[0015]

The present invention will be described in more detail with reference to the following examples, but as described above, the present invention is not limited to these examples. It may be applied in various ways in consideration of the cost and performance of the recording apparatus to be realized and the physical properties of the ink. [Embodiment 1] As the head 2 in FIG. 1, the head shown in FIG. 2A is equipped, and black ink having a surface tension of 42 dyn / cm, and cyan, magenta, and yellow having a surface tension of 33 dyn / cm. The ink was put in the ink tank 3, and color recording was performed on the recording paper (SK paper for Canon NP) 1. First, in the first line, printing is performed only with C, M, and Y, and paper is lined for one line, and then the nozzles 1B to 1B of the Bk head.
NB is used to perform black printing on the color printing section in the preceding line.
At the same time, Y, M, and C were also printed on the second line. This printing method was repeated to obtain a color print of A4 size. The obtained print had no bleeding at the color boundary and had good image quality in the black character area.

Example 2 Using the same apparatus, head and ink as in Example 1, color recording was carried out on the upper half of A4 paper and only black characters were printed on the lower half. The color recording portion was printed in the same manner as in Example 1, and the black character portion was printed two lines at a time by using all the 2N nozzles of the black head. As a result, the printing speed was increased and good printing quality was obtained. That is, there was no ink bleeding (bleeding) in the color recording portion, and the quality of the black character portion was good.

[Example 3] Color recording was performed in the same manner as in Example 1 except that the head shown in Fig. 2B was used as the head 2 in Fig. 1. First, in one scan, the nozzles (N + 1) B below the black head on the first line
2NB is used to print black, and after feeding one line, C, M, and Y are simultaneously printed on the black print of the previous line. This time,
Further, at the same time, black printing is performed on the third line by nozzles (N + 1) B to
Perform with 2NB. By repeating this procedure, color recording was carried out, and a recorded matter having no bleeding in the color portion and good quality in the black character portion was obtained on A4 paper.

[Embodiment 4] Using the same apparatus, head, and ink as in Embodiment 3, color recording was performed on the upper half of A4 paper, and only black characters were recorded on the lower half. The color recording method for the upper half was performed in the same manner as in Example 3. For the lower half black character printing, the first line is (NH) B ~ 2 of the Bk head.
Print with NB, put a line of paper, and print with all nozzles of Bk. After that, by printing all nozzles every time one line was fed, it was possible to improve the OD of black characters without reducing the printing speed. Of course, the print quality was also good.

[Embodiment 5] FIG. 6A shows a plan view of a heater substrate of a bubble jet head according to the present invention. The heater substrate has a width of 13.3 mm and a length of 4.7 mm, and has a thickness of about 2 μm on a silicon wafer having a film thickness of about 0.6 μm.
m silicon oxide layer is formed, and a HfB2 resistor layer having a thickness of about 0.6 μm, and a wiring thickness of about 0.5 μm.
m of aluminum is deposited by sputtering, and each is patterned by an appropriate photolithography process. Bk
There are 64 heaters for 360 dpi (about 70.6 μm pitch), and 24 heaters for Y, M, C each at 360 dpi. In FIG. 6A, for simplification, only the outer shape of the heater substrate and the heater are shown, 2 is a Y heater, 3 is an M heater, 4 is a C heater, and 5 is a Bk heater. . A film thickness of about 1 is formed as a passivation layer on these heaters and wiring.
A silicon oxide layer with a thickness of 0.5 μm and a tantalum layer with a thickness of about 0.5 μm are formed by sputtering, and are patterned by photolithography at the required locations. It should be noted that the heater groups for ejecting the inks of each color tone were formed so as to be separated by 16 nozzles.

FIG. 7A is an enlarged schematic plan view of a Y heater, FIG. 7B is an M and C heater, and FIG. 7C is an enlarged schematic plan view of a Bk heater. In the figure, reference numerals 11, 12, and 13 denote heater portions, and 10 denotes wiring. In this embodiment, the Bk heater has a width of 30 μm and a length of 150 μm, and the aluminum wiring has a resistance of 10Ω. The M and C heaters have a width of 19 μm and a length of 150 μm, the wiring is 17Ω, and the Y heater has a width of 1 μm.
The length was 5 μm, the length was 150 μm, and the wiring was 20Ω. An ink flow path pattern was formed on the heater substrate thus formed using a photosensitive dry film. Photosensitive dry film is Odeal SY-3 by Tokyo Ohkasha
25 was used. The dry film was laminated on the substrate by lamination, and the ink flow path pattern was pattern-exposed with a Canon mask aligner. Then, after shower development with trichloroethane, UV curing and heat curing were performed. Next, the ink liquid chamber pattern is similarly patterned on the glass having the ink supply port formed by using the photosensitive dry film, and then a photosensitive adhesive is applied on the pattern formed by the dry film and bonded to the substrate. It was As the photosensitive adhesive, CPA-4 (San Nopco) was used, and coating was performed by a roll coating method. The bonded sample was directly subjected to UV curing and heat curing. Next, the substrate was cut with a dicing saw to produce ejection elements, and finally a member for ink supply and electrical mounting were performed to produce a liquid jet recording head.

A liquid jet recording head having the appearance shown in FIG. 6B was produced. In FIG. 6B, 14 indicates a nozzle group for ejecting ink. These nozzle groups are 14 (a)
Of the Y ink ejection nozzle group, 14 (b) of the M ink ejection nozzle group, 14 (c) of the C ink ejection nozzle group, and 14 (d) of the Bk ink ejection nozzle group. Ink of each color tone is supplied to the nozzle group from an ink supply port indicated by 15. The Bk nozzle has a height of 23 μm and a width of 35 μm, and the discharge holes of the liquid jet recording head are M, C.
The nozzle had a height of 23 μm and a width of 24 μm, and the Y nozzle had a height of 23 μm and a width of 20 μm. An ink composed of 20 parts of diethylene glycol, 3 parts of ethyl alcohol, 3 parts of dye and 74 parts of water was supplied to the head. still,
For the color inks, some acetylenol was added. The surface tension of these inks is 45 dyn for black.
/ Cm, and the color ink was 32 dyn / cm. When a signal with an applied voltage of 28 V and a pulse width of 3 μsec was applied to the head, the droplet ejection amount of Bk ink was 8 lp.
1 refill time is 200 μsec, M and C ink ejection amounts are 48 pl, and refill time is 130 μse.
The ejection amount of the c and Y inks was 40 pl, and the refill time was 120 μsec. The refill time was measured by observing with an optical microscope the time from immediately after the ejection of ink droplets until the meniscus returned to the orifice surface.

The liquid jet recording head was mounted on the recording apparatus having the structure shown in FIG. As described above, this recording apparatus has at least two kinds of modes, that is, the character recording mode and the color recording mode, and the modes are automatically changed according to the recording signal. In the character recording mode, similarly to the conventional bubble jet recording method, recording is performed line by line (paper feed for 64 nozzles) at a drive frequency of 5 KHz using 64 nozzles. In the color recording mode, the recording method shown in FIG. 8 is used. The driving frequency in color recording mode is Y, M,
C-ink records at a drive frequency of 7.8 KHz and B
The k ink was ejected at 3.9 KHz. The nozzles for ejecting Bk ink of group a shown in FIG. 8 are nozzles (Bk) of group b.
Recording is performed by shifting one dot with respect to the pixel row of. b
The nozzles of the group perform printing by shifting one dot with respect to the nozzles of the group a, and the printing is performed so as to fill the spaces between the dots printed by the nozzles of the group a. The ejection timings of the a-group and the b-group are configured to be shifted by recording by applying an electric signal for each dot. The C, M, and Y ink ejection nozzles of the c, d, and e groups are 7.8 as described above.
Recording is performed at a driving frequency of KHz without thinning out. The paper feed in the color mode was performed for 24 nozzles each. With such a configuration, it becomes possible to perform recording at a drive frequency of 5 KHz in the character recording mode and 7.8 KHz in the color recording mode.

[Embodiment 6] A large number of substrates, each having an electrothermal conversion element having the structure shown in FIG. 9A and having the same film structure as in Embodiment 5, were formed on a silicon wafer. In addition, four through holes for ink supply were formed on each substrate by ultrasonic processing for each substrate. Nozzles were produced on the substrate by the following steps. In FIG. 9 (a), a heater 8 is provided on the substrate 7 in correspondence with the ejection of ink of each color tone.
(B), 8 (c), 8 (d). The heater is connected to the bonding pad 9 by wiring (not shown). Further, an ink supply hole 18 for supplying each ink is formed in each heater group. A positive type dry film (OZATEC-R-225: Hoechst) was laminated on the substrate and an ink flow path pattern was formed by photolithography. Next, 80:20 (molar of methyl methacrylate and glycidyl methacrylate)
l) A chlorobenzene solution of the copolymer was applied by spin coating and dried. The solution had a solid content of 0.
After the film was dried, 9 wt% of amine compound was added.
The coating was cured at 0 ° C for 10 hours. An ink discharge port pattern made of a silicon-based negative resist (SNR: Tosoh Corp. 9) was pattern-exposed on the coating film, and then oxygen plasma etching was performed by a parallel plate type dry etching apparatus using the resist as a mask to form an ink discharge hole. Finally, the positive type dry film was eluted with a 5 wt% sodium hydroxide solution to produce an ink ejection chip shown in Fig. 9 (b), and the nozzle arrangement of the chip has the configuration shown in Fig. 9 (b). , 2 in FIG. 9 (b)
There are 126 nozzles for discharging Bk ink in (a), 2
The nozzles for ejecting C, M and Y inks shown in (b), 2 (c) and 2 (d) were 48 nozzles, respectively. In addition, between the nozzles of each color, for example, the nozzle on the most C side of the Bk nozzle and the most B of the C
The distance from the k-side nozzle was only 1 dot. The ink ejection chip is mounted on a mount 19, and the mount is mounted on an ink tank and electrically mounted (not shown).
Enabled to be attached to recording device. When the same ink as in Example 5 was mounted on the liquid jet recording head and the same drive pulse as in Example 5 was applied, the discharge volume of Bk ink was 80 pl, the refill time was 150 μsec, and C
Ink ejection volume is 49 pl and refill time is 80
μsec, M ink was 80 μsec at 50 pl, and Y ink was 4 μl at 65 μsec. Recording was performed by mounting the liquid jet recording head on a recording apparatus having the configuration shown in FIG. The driving frequency in the character recording mode in the recording was 6.6 KHz, and recording was performed in two lines at a time. The paper was fed by 128 nozzles, that is, two lines of paper were fed and recorded. The driving frequency of the color ink in the color recording mode is 12.5 KHz, and the Bk ink is ejected 96 times adjacent to the nozzle ejecting the C ink.
Recording was performed by using nozzles at 6.25 KHz and thinning out one dot from each nozzle in the sub-scanning direction in the same manner as in Example 5. Further, the paper was fed by 48 nozzles at a time.

[Embodiment 7] With the same film structure as that of Embodiment 5, a substrate was formed in which only 128 electrothermal conversion elements for ejecting Bk ink were formed on a silicon substrate. In the same manner, substrates for discharging color ink on which 64 heaters were formed were prepared for C, M, and Y, respectively. Next, a nozzle made of a photosensitive resin and a top plate glass were bonded by the same means as in Example 5 to manufacture liquid ejecting recording heads for Bk, M, C and Y inks. These four liquid jet recording heads were integrated by applying an ink tank and electrical mounting so as to have the configuration shown in FIG.
Then, in the same manner as in Example 5, the recording apparatus having the structure shown in FIG. 10 was mounted. When the ejection volume and refill time of each ink were measured in the same manner as in Example 5, it was almost the same as in Example 5. In the present recording apparatus, the character recording mode has a configuration in which recording is performed in two lines at once using 128 nozzles at a driving frequency of 5 KHz. Further, the paper feed was for 128 nozzles (for two lines). In the color recording mode, the color ink ejection nozzle is 7.8 KHz.
And the Bk ink ejection nozzle had a drive frequency of 3.9 KHz. Further, the paper feed in this mode is set to 64 nozzles.

[Embodiment 8] Into the liquid jet recording head manufactured in Embodiment 5, the color inks of Y, M and C were prepared in the same manner as in Embodiment 5, and as the Bk ink, the face amount dispersion type ink was introduced. did. As the face amount dispersion type ink, a commercially available sumi ink (Sumihana: Pentel) was used. The refill time of this Bk ink was measured in the same manner as in Example 5, and was 250 μse.
It was c. In the same manner as in Example 5, the liquid jet recording head was mounted on the recording apparatus having the configuration shown in FIG. 10 for recording.
The drive frequency in the character recording mode was 4 KHz, the drive frequency of the color ink ejection nozzles was 7.8 KHz, and the drive frequency of the Bk ink ejection nozzles was 3.9 KHz in the color recording mode. The paper feed pitch was the same as in Example 5. As described above, according to the recording method of the present invention, it is possible to improve both the bleeding at the boundary between other color portions and the quality of black characters during color recording. In addition, color and monochrome printing became possible without slowing down the printing speed. Furthermore,
It is also possible to improve the OD of black characters without decreasing the printing speed.

[0026]

As described above, according to the present invention, in a color ink jet recording apparatus for ejecting a plurality of colors of ink to perform color recording, ink having a low fixability or ink ejection at a low frequency due to viscosity, droplet ejection volume or the like. Than the number of nozzles of the recording head that ejects ink other than that,
Bleeding can be suppressed, and high-quality recording can be performed without reducing the printing speed. In particular, the recording method of the present invention, that is, the number of nozzles of a recording head that ejects a black ink whose fixing property is slower than that of a color other than black is twice the number of nozzles of a recording head that ejects a color other than black. By controlling the print signal,
At the time of color recording, the black ink is ejected by a half of the total number of nozzles of the recording head that ejects the black ink, before or after one scan of printing a color other than black. According to the recording method in which the printing is performed by the total number of nozzles of the black ink recording head at the time of recording by, the bleeding at the boundary portion of the other color portion at the time of color recording and the black character quality are both improved. It becomes possible. Further, according to another recording method of the present invention, an ink having a large discharge volume such as a black ink and requiring a long time to dry the ink is thinned out for recording, and recording is performed so as to fill the thinned gap in a plurality of scans. In this case, bleeding can be suppressed and higher speed recording can be performed.

[Brief description of drawings]

FIG. 1 shows a serial type color inkjet recording apparatus.

FIG. 2 shows a nozzle arrangement of a head used in the present invention.

FIG. 3 shows a prior art head.

FIG. 4 is a schematic perspective view showing a configuration of a liquid jet recording head according to the present invention, FIG. 4A is an example of a liquid jet recording head in which nozzle rows are laterally arranged, and FIG. 4B is a nozzle row. 1 shows an example of a liquid jet recording head having a configuration in which are arranged vertically.

FIG. 5 is a schematic diagram of a liquid jet recording head having a configuration in which the number of nozzles ejecting Bk ink is increased as compared with the number of nozzles ejecting other color inks, as an example of the present invention. (A) is a schematic perspective view of a liquid jet recording head having a configuration in which four types of liquid jet recording heads are integrated, and (b) is a nozzle for ejecting ink of a plurality of color tones on one substrate. 3A and 3B are schematic perspective views of a liquid jet recording head that is configured integrally with each other, showing an outline of the configuration of the liquid jet recording head, and FIG. 7C is a schematic diagram showing an outline of the arrangement of nozzles. Further, FIGS. 3D and 3E are schematic views showing the structure of the present invention in an edge type head.
FIG. 1 is a schematic perspective view showing the configuration of a liquid jet recording head,
FIG. 7E is a schematic view showing the arrangement of nozzles.

6A and 6B are schematic perspective views showing a configuration of a liquid jet recording head prototyped in Example 5, where FIG. 6A is a perspective view of a substrate on which an electrothermal conversion element is manufactured, and FIG. FIG. 3 is a schematic perspective view of a liquid jet recording head that has completed the basic configuration of ink supply means and the like.

7A and 7B are diagrams schematically showing the shape of an electrothermal conversion element used in Example 5, where FIG. 7A is a Y ink ejection heater, and FIG. 7B is a C and M ink ejection heater. ,
FIG. 6C is a plan view of the heater for discharging Bk ink.

FIG. 8 is a schematic diagram showing an outline of a recording method in which recording is performed using the liquid jet recording head manufactured in Example 5.

FIG. 9 is a schematic perspective view showing the structure of a head of a liquid jet recording head according to the present invention manufactured in a side mold based on the sixth embodiment. (A) is a schematic perspective view of a substrate on which an electrothermal conversion element is formed, and (b) is a schematic perspective view of a liquid jet recording head in which nozzles are formed and mounting is completed.

FIG. 10 is a schematic perspective view showing the configuration of a recording apparatus that carries out recording by mounting the liquid jet recording head according to the present invention.

[Explanation of symbols]

1: Recording material 2: Head assembly 3: Ink cartridge 4: Nozzle array 1 (a) to (d): Ink tanks (a, b, c, d indicate each color tone) 2 (a) to (d) ): Ink ejection nozzle 3 ': Ink introduction member 4': Chip mounting member 5: Chip (heater substrate) 6: Ink ejection element 7: Silicon substrate 8: Heater 9: Bonding pad 10: Aluminum wiring 11, 12, 13: Heater 14: Ink ejection nozzle 15: Ink supply port 16: Driving IC 17: Base plate 18: Ink supply hole 19: Mount member 20: Inkjet head cartridge 21: Carriage 22: Cleaning motor 23: Transmission mechanism 24: Platen 25A, B : Guide shaft 26: Cap member 27: Drive motor 28: Drive belt 30: Grade 31: a blade-holding member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mayumi Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masashi Miyagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (6)

[Claims] 1. A color ink jet recording apparatus for ejecting a plurality of colors of ink to perform color recording of an ink that requires ink ejection at a low frequency due to a recording head of ink having a slow fixing property or viscosity or droplet ejection volume. A color ink jet recording apparatus, wherein the number of nozzles of the recording head is larger than the number of nozzles of the recording head which ejects other ink. 2. The number of nozzles of a recording head that ejects a black ink having a fixing property slower than that of another color is twice the number of nozzles of a recording head that ejects a color other than black. 1. The color inkjet recording device described in 1. 3. A color ink jet recording method using the apparatus according to claim 1 or 2, wherein the number of nozzles of the recording head for ejecting the black ink is half during color recording by controlling a print signal. Black ink is printed before or after one scan of printing a color other than black by a book, and when printing with only black ink, the printing is performed by the total number of nozzles of the black ink recording head. A color inkjet recording method characterized by the above. 4. The surface tension of black ink is 40 dyn.
4. The color ink jet recording method according to claim 3, wherein color recording is performed using an ink having a surface tension of less than 40 dyn / cm 2 of ink of a color other than black at a density of not less than / cm 2. 5. In a color ink jet recording method for performing color recording by ejecting inks of a plurality of colors, the number of nozzles ejecting ink of high viscosity or the number of nozzles of a recording head ejecting ink of large droplet ejection volume is , Which is an integral multiple of the number of nozzles for ejecting ink with low viscosity or nozzles for ejecting ink with a small droplet ejection volume, and after thinning and recording by the nozzles A color ink jet recording method, wherein recording is performed so as to fill the thinned gaps. 6. A recording is performed by setting a droplet ejection volume of black ink having a droplet ejection volume larger than that of other colors to be about twice as large as a droplet ejection volume of inks of other colors other than black. 6. The color inkjet recording method according to claim 5.