JP2005119100A - Recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording head with an arrangement of large/small ink droplet discharge orifices which can be best-suitably designed to their respective discharge characteristics, in the recording head which discharges a plurality of large/small ink droplets. <P>SOLUTION: In this recording head, a first discharge orifice rows and a second discharge orifice row which have their respective first discharge orifices and second discharge orifices for discharging ink droplets of the same type but the varying size arranged alternately and at the same pitched in a paper feed direction, are arranged in a carriage scanning direction. In addition, the first discharge orifice of the first discharge orifice row, the second discharge orifice of the second discharge orifice row, the second discharge orifice of the first discharge orifice row and the first discharge orifice of the second discharge orifice row, represent one discharge orifice row group positioned in the carriage scanning direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a print head, and more particularly to a recording head that ejects ink droplets having relatively different sizes.

  Most of the ink jet devices are known as printing devices in printers, copiers, etc. Among them, thermal energy is used as energy used for ink ejection, and ink jet printing devices that eject ink by bubbles generated thereby Has recently become widespread. As another application of the ink jet printing apparatus of this system, an ink jet textile printing apparatus that prints a certain pattern, pattern, composite image or the like on a cloth has recently been known.

  An ink jet head used in the ink jet printing apparatus as described above uses an electrothermal conversion element (hereinafter also referred to as a heater) as a device that generates thermal energy. A configuration with two heaters is adopted. On the other hand, as disclosed in Patent Document 1, there is also a technology that enables printing in various printing modes by changing the amount of ink ejected from each ejection port using an inkjet head equipped with a plurality of heaters. It is disclosed. In this way, by changing the amount of ejected ink, printing is performed with a larger ink ejection amount and lower recording resolution (faster carriage scanning speed) in the high-speed mode, and higher with a smaller ink ejection amount in the high-quality mode. Printing at a recording resolution (slow carriage scanning speed) makes it possible to achieve both high speed and high quality. With this compatibility, the user can obtain a comfortable image output by selecting an optimal print mode, which is very advantageous.

Further, in Patent Document 1, a discharge port arrangement as shown in FIG. 2 is proposed. 21 is an ejection port with a small ink ejection amount, and 22 is an ejection port with a large ink ejection amount.
Japanese Patent Laid-Open No. 08-183179

  However, in the case of the nozzle arrangement as shown in FIG. 2A, the large or small nozzle pitch becomes ½ compared to the large or small nozzle pitch. Further, in the case of the nozzle arrangement as shown in FIG. 2B, when trying to optimally design the ejection characteristics, the minimum pitch possible for the large nozzle array is smaller than the minimum pitch possible for the small nozzle array. Since it becomes large from the viewpoint of the flow path design, there is a possibility that it is restricted to a large pitch.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a recording head capable of optimally designing a large or small nozzle pitch including ejection characteristics. is there.

  For this purpose, the recording head according to the present invention has a discharge port array in which a plurality of discharge ports for discharging ink droplets are arranged in a first direction, and is different from the arrangement direction of the plurality of discharge ports. In a recording head that forms an image on a recording medium by scanning in the direction, the first ejection port and the second ejection port for ejecting ink droplets of relatively different sizes with the same ink have a predetermined pitch. The first discharge port array and the second discharge port array that are alternately arranged in the scanning direction are arranged in the scanning direction and the second discharge port of the first discharge port array and the second discharge port array The outlet and the second discharge port of the first discharge port row and the first discharge port of the second discharge port row have a discharge port row group positioned in the second direction.

  Further, in a recording head having an ejection port array group for ejecting ink droplets of a plurality of inks, it is preferable that at least one has an ejection port group configured as described above.

  The plurality of inks are black, cyan, magenta, yellow, cyan, magenta, yellow pigment, or light cyan, light magenta, or light yellow having a low dye density.

  Further, cyan, magenta, and yellow preferably have first and second ejection port groups.

  Alternatively, only cyan and magenta may have the first and second ejection port groups.

  Preferably, yellow, light cyan, light magenta, and light yellow have only one of the first ejection ports or the second ejection ports, which has a larger ejection ink droplet.

  More preferably, black has only a third ejection port that ejects ink droplets having a size different from that of the first ejection port and the second ejection port according to claim 1.

  From the above description, if the print head of the present invention is used, it is possible to optimally design a large or small nozzle pitch including ejection characteristics, and to make the amount of ejected ink multi-stage, high resolution and high density without graininess. Image output is now possible.

  According to the above configuration, it is possible to optimally design a large or small nozzle pitch including ejection characteristics, and it is possible to make the amount of ejected ink multistage.

(Example)
Hereinafter, embodiments of the ink jet recording apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 1a is a perspective view of an ink jet recording apparatus according to the present invention.

  The carriage 11 has a recording head 12 and a cartridge guide 13 mounted thereon, and can scan along the guide shaft 14 and the guide shaft 15. Further, the carriage and the recording apparatus are provided with detection means (not shown) for detecting the position of the carriage in the scanning direction.

  The recording paper 16 is sandwiched between a paper feed roller 18, a pinch roller (not shown), and a paper pressing plate 19, and conveyed to the front surface of the recording head 12 for recording.

  Two types of ink cartridges, a color ink cartridge 110 containing three colors of yellow, magenta, and cyan, and a black ink cartridge 111 are separately inserted into the cartridge guide 13 and connected to the recording head 12.

  FIG. 1B is a schematic diagram for explaining the structure of the ink jet recording head used in this embodiment. The discharge port 122 is provided with a corresponding heating element 124 (heater), and when a predetermined energy is applied to the heater 124 by the head drive circuit, a change in state due to the boiling film in the ink, that is, foaming. A phenomenon occurs, and ink droplets are ejected from the ejection port 122.

  The heater 124 is formed on the silicon substrate 121 by the same method as in the semiconductor process. Reference numeral 126 denotes an ink flow path for supplying ink to each ejection port.

  FIG. 3 shows the ejection port array of the recording head used in this embodiment. The carriage scans in the direction of arrow 35. Here, a color discharge port array will be described. The A column discharges cyan, the B column discharges yellow, and the C column discharges magenta ink droplets. Ink droplets with a small amount of ejected ink (about 2 pl) are ejected from the ejecting port 33, and ink droplets with a large amount of ejected ink (about 5 pl) are ejected from the ejecting port 34, respectively. Further, the discharge port interval 32 is 600 dpi pitch. There are 256 outlets for each color. The width 30, 31 of each discharge port of the ink flow path (126) indicated by the hatched portion is designed so that the ink flow path width 30 having a discharge port with a large discharge ink amount is larger, and discharge with a small discharge ink amount. The ink flow path width 31 having the outlet is designed to be smaller, and by arranging them alternately, it is possible to arrange the ejection ports at a pitch of 600 dpi. In this way, it is possible to adjust the flow resistance in the ink flow path and optimally design the return of ink after ejection. The above will be described in detail with reference to FIG.

  FIG. 4 is a schematic diagram showing the ink state of the recording head. In the initial state of A, the ink is filled up to the ejection port 122. When predetermined energy is applied to the heater 124 in this state, a state change due to the boiling film, that is, a foaming phenomenon occurs in the ink, and the ink droplet 40 is ejected from the ejection port 122. Then, the ink state becomes as shown in FIG. Thereafter, the ink returns in the direction of the arrow 41 and goes through the state shown in FIG. 4C and returns to the initial state shown in FIG. 4D. When the ink returns, the flow resistance of the ink flow path connected to the ejection port greatly depends on the difference in the time for returning to the initial state. Further, since the amount of retreat differs depending on the amount of ejected ink, the time for returning to the initial state varies.

  FIG. 5 shows an example of a recording method using the head of the present invention. For simplification of description, recording using cyan ejection port arrays will be described. Recording on the recording medium 51 is performed by discharging the recording head 52 while the carriage scans in the direction of the arrow 50. Note that the recording resolution in the scanning direction is 1200 dpi. Large ejection ink amount (53) and small dot (54) are respectively recorded on a grid of ejection port array 600 dpi and scanning direction 1200 dpi. As a result, it is possible to obtain an image with little graininess due to small dots in the highlight portion and a high density image due to large dots in the high density portion.

  FIG. 6 shows a color ejection port array of the recording head used in this embodiment. The difference from the first embodiment is that the yellow discharge port array of the B row is composed of only discharge ports with a large amount of discharge ink. In the recording head of this example, the graininess of yellow is less conspicuous than cyan and magenta, so yellow is recorded only with large dots. As a result, the area of the silicon substrate 121 of the recording head can be reduced as compared with the first embodiment, and the cost of the recording head can be reduced without deterioration of image quality due to graininess.

  FIG. 7 shows a color ejection port array of the recording head used in this embodiment. The difference from the second embodiment is that a discharge port array for discharging light cyan ink having a relatively low density with respect to the A line in the A ′ line, and light magenta with a relatively low density in the C ′ line with respect to the C line. This is the point that an ejection port array for ejecting ink is arranged. The A ′ row and the C ′ row have the same discharge port configuration as the B row.

  In the recording head of this embodiment, the graininess of light cyan and light magenta is inconspicuous, so even a large dot alone does not affect image quality, and it is possible to improve image quality with light ink while minimizing costs. .

(Other examples)
Examples 1 to 3 described above are for the color ejection port array of the recording head. In the first to third embodiments, a configuration in which the recording head has a black discharge port array together with the color discharge port array is usually used. In the present embodiment, the configuration of a recording head having a black discharge port array will be described.

  First, FIG. 8 shows a black discharge port array used in this embodiment. There are 320 ejection ports 81 arranged at a ejection port pitch (82) of 600 dpi, from which about 30 pl of ink droplets are ejected. A large black ink droplet with respect to color and a large number of nozzles make it possible to achieve both high-quality color printing and high-speed, high-density character printing.

  FIG. 9 shows an example of a recording head used in this embodiment. (A) to (C) are views as seen from the ejection opening of the recording head. Reference numeral 90 denotes a recording paper conveyance direction, and reference numeral 91 denotes a carriage scanning direction. (A) to (C) 92 is black, and the dotted line indicates the black discharge port array.

  (A) employs the color ejection port array group of the first embodiment, 93 is a color ejection port array group, and the thick line indicates ejection port arrays with large and small ejection ink amounts of cyan, magenta, and yellow, respectively. Show. (B) employs the color ejection port array group of Example 2, 94 is the ejection port array group, the thick line is the ejection port array, the thin line is the cyan and magenta ejection ink amount large and small, An ejection port array having only a large amount of yellow ejection ink is shown. Further, (C) employs the color ejection port array group of Example 3, 95 is a color ejection port array group, the thick line is an ejection port array with a large and small ejection ink amount for cyan and magenta, and a fine line Indicates an ejection port array having only large ejection ink amounts of light cyan, light magenta, and yellow.

a is a perspective view of the ink jet recording apparatus used in this embodiment, and b is a schematic diagram showing a structure of a recording head. Schematic diagram of Example of Patent Document 1 FIG. 6 is a diagram of a color ejection port array of a recording head used in Example 1. Schematic diagram of ink status in ink ejection An example of a recording method using the recording head of Example 1 FIG. 5 is a diagram of a color ejection port array of a recording head used in Example 2. Diagram of color ejection port array of recording head used in Example 3 Diagram of black ejection port array of recording head Diagram of recording head of other embodiment

Claims (7)

An ejection port array having a plurality of ejection ports for ejecting ink droplets arranged in a first direction, and scanning on a recording medium by scanning in a second direction different from the arrangement direction of the plurality of ejection ports. In a recording head for forming an image on
A first ejection port array and a second ejection port array in which first ejection ports and second ejection ports for ejecting ink droplets of relatively different sizes with the same ink are alternately arranged at a predetermined pitch. The first discharge port of the first discharge port array and the second discharge port of the second discharge port column and the second discharge port and the second discharge port of the first discharge port column arranged in the scanning direction. A recording head, wherein the first discharge port of the outlet row has a discharge port row group positioned in the second direction.   A print head having an ejection port array group for ejecting ink droplets of a plurality of inks, wherein at least one of the print heads has the ejection port group according to claim 1.   The plurality of inks are black, cyan, magenta, yellow, and cyan, magenta, yellow pigment, or light cyan, light magenta, or light yellow having a low dye density. Recording head.   4. The recording head according to claim 3, wherein cyan, magenta, and yellow of the ink ejected from the recording head have the ejection port group according to claim 1.   The recording head according to claim 3, wherein cyan and magenta among the inks ejected from the recording head have the ejection port group according to claim 1.   2. Of the inks ejected from the recording head, yellow, light cyan, light magenta, and light yellow are ejected in the larger one of the first ejection ports or the second ejection ports according to claim 1. The recording head according to claim 5, wherein only the outlet is provided. The black has only a third discharge port for discharging ink droplets having a size different from that of the first discharge port and the second discharge port according to claim 1. Recording head.

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