JPH10151743A - Ink jet recording head and its recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a high-quality full color printing process to be carried out without changing a printing speed by forming two rows of nozzles for black ink, in an ink jet recording head for full color. SOLUTION: The marking (a) indicated a dot position when a single color ink is printed. When intermediate color is produced, by using two printing colors there are two different printing methods, i.e., a printed dot superpositioning method and a printed dot partially overlapping method. This full color printing process is performed by deviating each of color ink nozzles by 1/3 pitch (about 23μm) in the nozzle row direction and besides, delaying the timing of printing by each of ink jet nozzles by 1/3 cycle. When adopting either of the printed dot superpositioning method or the printed dot partially overlapping method for representing the intermediate color, a printed image tends to be a mixed representation by both methods on account of the reproducibility of a printed dot position, as far as a printed dot of ±20μm as used in a conventional method is used. Consequently, the ability to represent a color is limited. On the other hand, this new printing method makes it possible to print a 2-3μm dot so that the ability to represent a color is significantly enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a recording apparatus of the type in which thermal energy is used to fly ink droplets toward a recording medium, and a method of manufacturing the same.

[0002]

2. Description of the Related Art An ink jet recording apparatus of a type in which a part of ink is rapidly vaporized by pulse heating and ink droplets are ejected from an orifice by its expanding force is disclosed in JP-A-48-9622 and JP-A-54-962. No. 51837 discloses this.

The simplest method of the pulse heating is to apply a pulse current to the heating resistor. A driving LSI and a thin film heating resistor for applying the pulse current are formed on the same silicon substrate. The applicant of the present invention can realize an ink jet print head having a small size and high thermal efficiency, which is disclosed in JP-A-06-71888 and JP-A-06-29771.
4, JP-A-07-227567, JP-A-08-20
No. 110, JP-A-08-207291 and the like. When this technique is applied, it is possible to form two-dimensionally large-scale and high-density ink discharge nozzles, for example, 30 to 60 pp.
It has become possible to realize even an A4 full-color printer of m (pages / minute) (currently about 1 ppm).

[0004] Moreover, the characteristic of this head is firstly that the head
Second, in the definition, the nozzles having a diameter of about 25 μm are linearly arranged at an interval of about 35 μm (about 720 dpi) because almost all of the ink filled on the nozzle is discharged. Thirdly, since it can be manufactured collectively in units of about 100,000 nozzles / 5 inch wafer, even an integrated full-color line head can be manufactured at low cost. (See JP-A-07-171956).

[0005]

In the above-described batch manufacturing method, the length of the nozzle (orifice plate thickness) and the height of the ink partition have the same dimensions for each color. Requires changing the nozzle diameter. On the other hand, it is necessary to increase the nozzle diameter as much as possible in order to secure the amount of ejected ink necessary to obtain a sufficient print density. In this case, the size of the nozzle diameter is limited. Therefore, in the case of the above configuration, there is a potential drawback that the range in which the amount of ejected ink can be changed for each color is narrow.

In general, in the case of a full-color printer using black ink in addition to the three primary colors, the ratio of the discharge amount of the color ink to the discharge amount of the black ink is set at about 1: 2 from the viewpoint of the intermediate color expression and the prevention of excessive ink wetting. It is said that it is desirable. That is, if the above-described batch manufacturing method is used, there is a problem that the discharge amount of the black ink is insufficient with respect to the discharge amount of the color ink, and the expression of the black density is restricted.

An object of the present invention is to provide an easy method that can make the discharge amounts of the color ink and the black ink 1: 2 in the ink jet recording head having a structure manufactured by using the above-described batch manufacturing method. is there.

[0008]

The object of the present invention is to provide a plurality of heating resistors formed on a first surface of a Si substrate, and a plurality of heating resistors formed on the same Si substrate for driving the heating resistors. A driving LSI connected to a resistor, a plurality of ejection openings for ejecting ink droplets in a direction perpendicular or substantially perpendicular to the heating resistor by sequentially applying a pulse to the plurality of heating resistors; A plurality of individual ink passages provided on the Si substrate corresponding to each of the plurality of ejection openings; a common ink passage provided on the Si substrate so that all of the individual ink passages communicate with each other; An ink groove provided in the Si substrate so as to be conducted over the entire length of the common ink passage, and a second surface of the Si substrate so that the ink groove communicates with a second surface which is a back surface of the first surface of the Si substrate. One or more in A first ink jet recording device structure comprising a supply hole, a substantially identical configuration as the ink jet recording device of the first configuration, and a second ink channels,
A common ink passage arranged substantially symmetrically on both sides of the ink groove, a plurality of individual ink passages, an ink ejection recording device of a second configuration having a plurality of heating resistors and ejection ports, This problem can be solved by arranging a plurality of first and second ink jet recording devices on the same Si substrate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific example of a head having a nozzle arrangement density of 360 dpi will be described below with reference to the drawings.

FIG. 1 is an external view of a head chip in which two rows of 360 dpi nozzles are arranged for black ink and one row for three primary color inks.

The ink passes from an ink supply hole 9 in an ink cassette 8 through an ink supply hole 7, an ink groove 6, a common ink passage 12, and an individual ink passage 13 provided in the Si wafer 1 to an ink droplet 10 from a nozzle 5. Is discharged. The driving source for ink ejection is a heating resistor (not shown) formed on the Si wafer 1, and the same S
An ink droplet 10 is ejected from a nozzle 5 in accordance with a drive pulse of a drive LSI 2 provided on the i-wafer 1.

In this case, the number of nozzles in each nozzle row is 12
The figure shows the case where the number is eight, and one scan is about 8.9 m.
m width full color printing is possible. Chip size is about 8.
It is 5 mm × 10 mm, which is connected to and mounted on a four-color, one-body type ink cassette 8 (8 in FIG. 2 is a part thereof). Note that even if the number of nozzles in each nozzle row is increased to 256 or 512, the chip width remains unchanged at 8.5 mm, and only the length is increased to about 19 mm or about 37 mm, and each scan takes about 17. It goes without saying that the head can constitute a printer capable of performing full-color printing with a width of 8 mm and a width of about 35.6 mm.

FIG. 2 is a sectional view taken along the line AA 'of the head of FIG. 1 showing the vicinity of the nozzles for magenta ink and black ink.
The nozzles 5 are arranged at a pitch of about 70 μm in the direction perpendicular to the plane of the paper of FIG. 2, and the black ink nozzles are arranged symmetrically on both sides of the ink groove 6 symmetrically on both sides. However, the left and right nozzle positions are shifted in the nozzle row direction by a half pitch (about 35 μm) (staggered arrangement) so that they do not overlap each other when printing with black ink. In this example in which the thickness of the partition 3 is 10 μm, the thickness of the orifice plate 4 is 25 μm, and the inner diameter of the nozzle 5 is 45 μm, the amount of ink ejected at one time is about 50 pl, and the dot diameter when printing on plain paper is about It was 65 μm. That is, the printing density in the nozzle row direction (sub-scanning direction) is 72
0 dpi, which enables printing in which dots are completely connected.

On the other hand, the nozzle for magenta ink is shown in FIG.
Are formed only on one side of the ink groove 6, and the structure including dimensions is almost the same as that of the black ink nozzle. That is, the structure is the same as that of the case where the inner diameter of the nozzle 5 is slightly changed depending on the color density of the color ink, and that the width of the ink groove 6 is slightly narrower in the case of color ink. Therefore, the discharge amount of the color ink at one time is about 50 pl, the dot diameter when printing on plain paper is about 65 μm, and the print density in the nozzle row direction (sub-scanning direction) is 3
The dots are printed at intervals of about 5 to 10 μm.

Using this head, printing in the main scanning direction is
FIG. 3 shows an example of printing all dots in the case of 60 dpi.

(A) is a print example of color ink, (b) and (c) are print examples of black ink, and the difference between (b) and (c) is whether the print timing is shifted by 周期 cycle. Is just different. When the printing of each nozzle row is sequentially performed by continuous driving or block driving, it goes without saying that the position of each nozzle in the nozzle row is shifted by the shift of the driving timing. Of course, the heater employed here (see JP-A-6-71888, JP-A-6-297714, etc.) has a smaller input energy of about 1/10 than that of the heater according to the prior art, and is 128
Since it is possible to drive all the nozzles at the same time for the number of nozzles, a case where the nozzles are arranged linearly will be described.

Now, while the color ink is printed as shown in FIG. 3A, the black ink is printed as shown in FIG. 3B or 3C. Printing can be performed with high quality.
In particular, it can be seen that (c) has a high black density and enables smoother three-gradation display. And (c)
The reason why printing can be performed with good reproducibility as shown in Fig. 1 is due to the use of a head in which two ink rows arranged at a pitch of about 70 µm are arranged side by side on the same substrate as shown in Fig. 1. This is because it is difficult to produce a head in which 128 nozzles are arranged at 360 dpi in the conventional technology, and even if it is possible, only a head in which 128 nozzles are formed in one row can be produced. Therefore, even when two heads are fixed to the carriage of a low-cost printer and printing is performed, the relative positional accuracy between the cartridges is ± 2.
The limit is about 0 μm, and ± 2 to 3 shown in FIG.
The dot position accuracy of μm cannot be realized.

On the other hand, in the present invention, the head is manufactured by applying the semiconductor manufacturing process technology.
It is easy to make the array density of 720 dpi or more, and in that case, the print dot diameter is about 30 μm, which is too small to be practical. Nevertheless, the head shown in FIG. 1 can be manufactured, and the printing can be performed with high accuracy in the pattern shown in FIG. 3C (position accuracy of ± 2 to 3 μm).

Next, color printing will be described.

FIG. 3A shows a dot position when one color ink is printed. When an intermediate color is produced by two-color printing, there are a method of overlapping print dots and a method of shifting the print dots. FIG. 4 shows the optimum dot arrangement when this shifting method is adopted. The arrangement of the nozzles for each color ink is shifted by １ ／ pitch (about 23 μm) in the nozzle row direction, and the printing timing is shifted by one. It can be executed by shifting by / 3 cycle.

Regardless of which of the superimposition method and the shift method is adopted for the intermediate color expression, the reproducibility of the dot position to be printed is ± 20 μm of the conventional method, and both types are mixed, so that the color expression performance is limited. is there. On the other hand, in the present invention, the printing dot position accuracy can be set to ± 2 to 3 μm, and the expression ability of the color is greatly improved. This is possible because, as described in the case of the black ink case, the relative positional accuracy of each color nozzle is manufactured by ± 1 μm or less by the photolithographic method, and the distance between each nozzle row is 1 mm. Because the distance is only 0.5 to 2.0 mm, high positional accuracy in the main scanning direction can be realized only by the timing accuracy of the ejection pulse.

The data relating to the dot position accuracy described above
Needless to say, the data is limited to the range of one scan, and the problem of the connection with the next scan depends on the accuracy of the carriage and the paper feed. However, even if the accuracy of the connection is slightly lower, a large improvement in the ability to express colors is still achieved by the present invention. In particular, the black expression can display three gradations, and the printing speed does not decrease. Of course, the present invention also makes it possible to easily manufacture a line head. In this case, the problem of splicing by paper feeding is completely eliminated, and high-speed printing and high-quality printing can be achieved simultaneously, in a small size and at low cost. become.
Also, the color nozzle row shown in FIG.
It is easy to use six rows, and it is possible to provide a full-color printer with more complexity and good reproducibility.

[0023]

According to the present invention, tens of thousands to several tens on a Si substrate including a driver circuit using a semiconductor manufacturing process technology.
Even in a full-color inkjet recording head of a method of manufacturing 100,000 nozzles at a time, it is possible to execute high-quality full-color printing without changing the printing speed by setting the number of black ink nozzle rows to two. Was.
Also, by shifting these two nozzle rows by 1/2 pitch in the nozzle row direction and by shifting the print timing by 1/2 cycle, the black density is high and the linearity is good.
Gray scale display is now possible. Further, since all of the full-color nozzles including black are arranged with high precision on the same substrate, high-quality full-color recording has become possible. In particular, since a line head can be easily manufactured, a high-speed, high-quality, low-cost full-color printer can be realized.

[Brief description of the drawings]

FIG. 1 is an external view of a head chip according to the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 (including a part of the cassette).

FIG. 3 is a print sample when printing is performed using the head of FIG. 1;

FIG. 4 is an example of a dot position of two colors printed using the head of FIG. 1;

[Explanation of symbols]

1 is a Si wafer, 2 is a driving LSI, 3 is a partition, 4 is an orifice plate, 5 is a nozzle, 6 is an ink groove, 7 is an ink supply hole, 8 is a cassette, 9 is a cassette side supply hole,
10 is an ink droplet, 11 is a bonding pad, 12 is a common ink passage, and 13 is an individual ink passage.

Claims (3)

[Claims] 1. A plurality of heating resistors formed on a first surface of a Si substrate, and a driving resistor formed on the same Si substrate for driving the heating resistors and connected to the heating resistor. L
SI, a plurality of ejection openings for ejecting ink droplets in a direction perpendicular or substantially perpendicular to the heating resistor by sequentially applying a pulse current to the plurality of heating resistors, and corresponding to each of the plurality of ejection openings. A plurality of individual ink passages provided on the Si substrate, and a common ink passage provided on the Si substrate so that all of the individual ink passages communicate with each other;
An ink groove provided in the Si substrate so as to be conducted over the entire length of the common ink passage;
S to communicate with a second surface, which is the back surface of the first surface of the i-substrate.
an ink jet recording device having a first configuration comprising one or more ink supply holes formed in a second surface of the i-substrate; An ink groove, a common ink path arranged substantially symmetrically on both sides of the ink groove, a plurality of individual ink paths, a plurality of heating resistors, and a discharge port. An ink jet recording head comprising: a plurality of ink jet recording devices having a first configuration and a plurality of ink jet recording devices having a second configuration are juxtaposed on the same Si substrate. 2. The ink jet recording device according to claim 2, wherein the ejection port arrays arranged on both sides of the ink groove are mutually shifted by 1/2 pitch in the ejection port array direction. The ink jet recording head according to claim 1, wherein 3. A recording apparatus for performing full-color printing using the ink jet recording head according to claim 1.