JP2005088486A - Recording head, head cartridge using recording head, and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording head in which the whole liquid discharging apparatus can be down-sized by making a dimension and a width of the head small, and a high quality printing with an excellent gradation is possible, and which has excellent installation properties and portability, in the inkjet recording head using a shade multiple values recording method. <P>SOLUTION: In the recording head 1, a row of discharging holes 21M, 22M, 21C and 22C for dark magenta and cyan inks (M and C) and a row of discharging holes 21LM, 22LM, 21LC and 22LC for light magenta and cyan inks (LM and LC) are oriented in the discharging hole arranging direction (a sub-scanning direction). A row of two or more discharging holes 21Y, 22Y, 21Bk and 22Bk for yellow and black inks (Y and Bk) having no dark and light ink is arranged in the same sub-scanning direction. Each of the rows of the discharging holes is arranged into two rows in a zig-zag manner. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recording head for ejecting ink droplets, a head cartridge using the recording head, and an ink jet recording apparatus, and more specifically, a “dark ink” having a high density of similar colors and a “light ink” having a low density. The present invention relates to a recording head that discharges “ink without density” that is not divided into dark ink and light ink, a head cartridge using the recording head, and an ink jet recording apparatus.

  The present invention also includes a printer, a copier, a facsimile having a communication system, and a printer unit for recording on a recording medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The present invention relates to a recording head that can be applied to an apparatus such as a word processor, an industrial recording apparatus combined with various processing apparatuses, and an apparatus for applying the recording head. Note that “recording” in the present invention refers not only to giving an image having a meaning such as a character or a figure to a recording medium but also to giving an image having no meaning such as a pattern to the recording medium. Is also meant.

  Conventional inkjet recording methods generally record ink by ejecting ink from a plurality of ejection ports provided in a recording head based on a recording data signal and attaching ink droplets to a recording medium such as paper. . This recording method is used, for example, in a recording unit such as a printer, a facsimile, or a copying machine.

  As an ejection method in the above apparatus, in order to eject ink, a heating element (also referred to as an electrothermal energy conversion element) is provided in an ink path near the ejection port, and an ink is applied by applying an electrical signal to the heating element. There are known a method in which bubbles are generated by locally heating, and ink is ejected from the ejection port by a change in ink pressure caused by the bubbles, and a method using a piezoelectric element or an electromechanical transducer using electrostatic force.

  As a halftone expression method using this type of ejection method, a dot density control method that records ink dots of a certain size and controls the number of dots per unit area to express a halftone, or A dot diameter control method for expressing a halftone by controlling the size of a recording dot is generally known.

  Here, since the latter dot diameter control method has restrictions such as requiring complicated control to slightly change the size of recording dots, the former dot density control method is generally used. There are many.

  Also, when an ink ejection method using an electrothermal conversion element is used, a recording head according to this method is relatively easy to manufacture and can be printed at a high resolution because of its high density. However, since it is relatively difficult to control the amount of pressure change, it is difficult to modulate the diameter of the recording dots, and it is therefore difficult to use the dot diameter control method.

  As described above, the dot density control method is often used as the halftone expression method, and the systematic dither method is known as one of the representative binarization methods of the halftone expression. However, this method has a problem that the number of gradations is limited by the matrix size. That is, in order to increase the number of gradations, it is necessary to increase the matrix size. However, if the matrix size is increased, one pixel of a recorded image composed of one matrix becomes larger and the resolution is impaired. Arise.

  In addition, a conditional decision type dither method such as an error diffusion method is known as another typical binarization method. This is an independent decision type dither method in which the above-described systematic dither method is binarized using a threshold value unrelated to the input pixel, whereas the threshold value is changed in consideration of the peripheral pixels of the input pixel. Is the method. The conditional decision type dither method represented by this error diffusion method has good compatibility between gradation and resolving power, and when the original image is a printed image, the occurrence of moiré patterns in the recorded image is extremely low. There are advantages. However, on the other hand, there is a problem that graininess is conspicuous in the bright image portion and the evaluation of the image quality is lowered. This problem is particularly noticeable in recording with a low recording density.

  In order to make the above-mentioned graininess inconspicuous, two recording heads for ejecting light ink (hereinafter also referred to as light ink) and dark ink (hereinafter also referred to as dark ink) are provided, and from the bright part of the image A recording method has been proposed in which recording dots are formed with light ink in the halftone portion and recording dots are formed with dark ink from the halftone portion to the dark portion.

  According to such a multi-value recording method using a plurality of dark and light inks with different densities for the same color, the gradation of the highlight portion is improved particularly as the multi-value is increased, and the graininess due to dots is reduced. It becomes possible to improve the image quality. This is because the noise of single dots is eliminated by driving low density (light) ink into the highlight area.

  Such a light and shade multi-value recording method is disclosed in Patent Document 1 or Patent Document 2. The carriage is equipped with four recording heads of cyan (C), magenta (M), yellow (Y), and black (K), and each recording head ejects dark ink of each ink color. An ejection port array for ejecting light ink and an ejection port array for ejecting light ink are formed.

  Patent Document 3 discloses another configuration. Black (BK), cyan (C), magenta (M), yellow (Y), light magenta (LM), and light cyan (LC) ejection port arrays are arranged in the main scanning direction.

In addition, Patent Document 4 relating to the application of the present applicant shows a recording apparatus that has a diluent tank, dilutes ink with a diluent, and prints light ink, and includes a head to which ink of each color is supplied. The heads to which each color ink and dilution liquid are supplied are arranged in the main scanning direction.
JP 2001-71540 A JP 2002-254679 A JP 2001-171154 A JP 2001-113729 A

  The recording heads disclosed in Patent Literature 1 and Patent Literature 2 are provided with dark and light inks for all four colors of black, cyan, magenta, and yellow, and are arranged with ejection port arrays for a total of eight colors. Will become bigger. In order to make the print heads small, the ink color with light and shade is reduced to the minimum, and in order to make the print heads small and improve the image quality, how to arrange these ink discharge ports is a problem. It becomes.

  Further, since the droplet discharge head disclosed in Patent Document 3 has 6 to 9 discharge port arrays of 6 to 9 colors including dark and very light inks, the width of the head is increased. In Patent Document 3, an ejection port array for each color is taken as an example. However, if it is intended to fill with a single droplet ejection head scan, it is effective to provide two rows of ejection ports for each color in a staggered arrangement. In that case, the number of ejection port arrays doubles to 12-18, and the width of the head further increases. As for the width of the ink jet recording apparatus, at least the width of the head is required on both sides in addition to the paper width. Therefore, when the head width is increased, the entire apparatus is increased, which becomes an obstacle to downsizing of the apparatus. Since dark and light inks are mounted in order to reduce the graininess of the image, the number of ejection port arrays is increased, the width of the recording head is increased, and the size of the apparatus is accordingly increased.

  It is an object of the present invention to make it possible to reduce the size of the recording head and the width of the recording head in a recording head using a light / dark multi-value recording method, thereby reducing the overall size of the liquid ejection apparatus, and improving the gradation. An object of the present invention is to provide a liquid ejection apparatus capable of printing with excellent image quality and excellent in installation property and portability.

  According to the first aspect of the present invention, there is provided a recording head having a plurality of ejection ports for ejecting ink, and a relative relationship between an ejection port array composed of a plurality of ejection port arrays for ejecting dark ink of a similar color and a relatively high density, In particular, there are two or more colors of an ejection port array that ejects light ink having a low density, and a plurality of ejection ports that eject ink that does not have light and shade. In a recording head having an outlet row and two or more ejection port rows arranged in the sub-scanning direction, at least two ejection port rows for ejecting the ink having no light and shade are arranged in the sub-scanning direction. And Here, “ink having no light and dark” means an ink in which similar color inks are not divided into a dark ink having a relatively high density and a light ink having a relatively low density.

  According to a second aspect of the present invention, in the recording head of the first aspect, the ink having no contrast is a black ink and a yellow ink.

  According to a third aspect of the present invention, in the recording head of the second aspect, the ejection port array that ejects the black ink does not overlap with the ejection port array that ejects the dark ink in the main scanning direction.

  According to a fourth aspect of the present invention, in the recording head according to the first to third aspects, the ejection port array is arranged so that the color of the ink ejected from the ejection port array is symmetric in the main scanning direction. It is characterized by.

  According to a fifth aspect of the present invention, in the recording head of the fourth aspect, the ejection port array at the center of symmetry of the ejection port array arranged to be symmetric in the main scanning direction is an ejection port that ejects black ink and yellow ink. It is characterized by being a row.

  According to a sixth aspect of the present invention, in a head cartridge in which an ink jet head that discharges ink droplets and an ink tank that supplies ink to the ink jet head are integrated, the ink jet head is the recording head according to any one of the first to fifth aspects. It is characterized by that.

  According to a seventh aspect of the invention, there is provided an ink jet recording apparatus equipped with an ink jet head for discharging ink droplets, wherein the ink jet head is the recording head according to any one of the first to fifth aspects or the head cartridge according to the sixth aspect. It is characterized by being.

The recording head, the head cartridge, and the ink jet recording apparatus of the present invention have the following effects.
(Claim 1) Since at least two ejection port arrays for ejecting ink having no density are arranged in the sub-scanning direction, the ejection port arrays for ejecting ink having no density can be arranged in a small space, and the density ink is mounted. Even in a recording head having a large number of discharge port arrays, it is possible to prevent the width of the recording head from increasing. Therefore, the size of the recording apparatus main body can be reduced.

  (Claim 2) The ink having no shading includes black and yellow, and the yellow and black ejection port arrays are arranged in the sub-scanning direction. Therefore, the printing of the print head differs between yellow printing and black printing. . Therefore, there is a time difference between the yellow print and the black print by the scan time of the recording head. Depending on the time, the next ink is printed after the previously printed ink has penetrated and fixed to the recording medium or dried to some extent. Is done. Accordingly, it is possible to reduce the boundary bleeding between yellow and black, which are most likely to cause bleeding.

  (Claim 3) The ejection port array for ejecting black ink is arranged so as not to overlap the ejection port array for ejecting dark ink in the main scanning direction. There is a time difference between scans of the recording head, and bleeding is difficult to occur.

  (Claim 4) Since the ejection port array is arranged so that the color of the ink ejected from the ejection port array is symmetric in the main scanning direction, it is possible to prevent occurrence of color unevenness due to reciprocal printing, The enlargement of the recording head width due to the symmetrical arrangement can be reduced.

  (Claim 5) Since the ejection port array at the center of symmetry of the ejection port arrays arranged to be symmetric is the ejection port array that ejects black ink and yellow ink, the size of the recording head can be reduced. it can.

  (Claim 6) In a head cartridge in which an ink jet head for ejecting ink droplets and an ink tank for supplying ink to the ink jet head are integrated, the recording head is small, so the head cartridge can also be miniaturized.

  (Claim 7) Since the ink jet head is equipped with the recording head according to any one of claims 1 to 5 or the head cartridge according to claim 6, an image with low gradation and good gradation can be obtained and printed. High speed and a small inkjet recording apparatus can be realized.

The present invention is a recording head having a plurality of ejection openings for ejecting ink, and has a relatively high density with a series of ejection openings that are composed of a plurality of ejection openings that eject a dark ink having a relatively high density in the same color. An ejection port array composed of a plurality of ejection port arrays that eject low-light ink, and an ejection port array composed of a plurality of ejection port arrays that eject ink that does not have light and shade and have two or more colors that do not have light and shade. And a recording head in which two or more ejection port arrays are arranged in the sub-scanning direction, wherein at least two ejection port arrays for ejecting the ink having no density are arranged in the sub-scanning direction. Here, “ink having no light and dark” means an ink in which similar color inks are not divided into a dark ink having a relatively high density and a light ink having a relatively low density.
According to the present invention, since at least two ejection port arrays for ejecting ink having no density are arranged in the sub-scanning direction, the ejection port arrays for ejecting ink having no density can be arranged in a small space. Even in a recording head that is mounted and has a large number of ejection port arrays, it is possible to suppress the increase in the width of the recording head. Therefore, the size of the head cartridge mounted with the recording head and the main body of the ink jet recording apparatus can be reduced.

Hereinafter, embodiments of the present invention will be described based on examples shown in FIGS.
FIG. 1 is a diagram schematically illustrating a main part of a recording head according to a first embodiment of the present invention. FIG. 1A is a diagram of a surface on which a discharge port of the recording head is formed as viewed from the outside of the discharge port. FIG. 1B is a partially enlarged view of the discharge port, and FIG. 1C is a cross-sectional view in the main scanning direction of the recording head of FIG.
As shown in FIG. 1C, the recording head 1 of Example 1 includes a substrate 3 including a heating resistor element 2 as an energy conversion element, and an orifice plate 5 that forms an ejection port 4.

  In the recording head 1 of the first embodiment, the substrate 3 is formed of a silicon single crystal having a surface orientation <100>. On the upper surface (connection surface with the orifice plate 5), as shown in FIG. A driving circuit 6 including a driving transistor for driving the heating resistor element 2, a contact pad 7 for connecting to a wiring board (not shown), a wiring 8 for connecting the driving circuit 6 and the contact pad 7 and the like are semiconductors. It is formed using a process. Further, the substrate 3 is provided with six through holes formed by anisotropic etching in a region excluding the drive circuit 6, the heating resistor element 2, the wiring 8, and the contact pad 7. Ink supply ports 9 for supplying liquid to the columns 21Y / 22Y, 21M / 22M, 21C / 22C, 21Bk / 22Bk, 21LM / 22LM, and 21LC / 22LC are formed. FIG. 1A schematically shows a state in which a substantially transparent orifice plate 5 is placed on the substrate 3, and the ink supply port described above is omitted.

  The orifice plate 5 provided on the substrate is formed of a photosensitive epoxy resin in the first embodiment, and communicates with the discharge port 4, the liquid flow path 10, and the ink supply port 9 corresponding to the heating resistance element 2 described above. A common liquid chamber 11 is formed. Here, after the anisotropic etching described above is performed, a silicon oxide film or a silicon nitride film is formed on a silicon substrate, and then an orifice plate 5 having a through hole, a discharge port, and a liquid flow path 10 is formed to supply ink. It is desirable to remove the silicon oxide film or silicon nitride film at the mouth because an inexpensive and precise ink jet head can be produced.

  The recording head 1 having the substrate 3 and the orifice plate 5 ejects a liquid such as ink from the ejection port 4 by utilizing the pressure of bubbles generated by film boiling due to thermal energy applied by the electrothermal transducer. And recording.

  In the recording head of Example 1, the ejection port arrays 21M, 22M, 21C, and 22C for dark magenta and cyan ink (M, C) and the ejection port arrays 21LM, 22LM, and 21LC for light magenta and cyan ink (LM, LC), 22LC are arranged in the ejection port alignment direction (sub-scanning direction), and two or more yellow and black (Y, Bk) ejection port arrays 21Y, 22Y, 21Bk, 22Bk that do not have dark and light inks are arranged in the sub-scanning direction. It is an arrangement. Each discharge port array is arranged in two rows in a staggered manner.

  In the recording head of Example 1, yellow (Y) and black (Bk) do not have dark and light inks. Since there are 128 ejection openings for each color row at a pitch of about 42 μm (1/600 inch) and a 2-row staggered arrangement, there are 256 ejection openings for each color. Since the 600 dpi discharge ports are arranged in two rows in a staggered manner, 1200 dpi printing is possible with a single scan of the recording head. Since black ink is used only in the high density portion of the image, the granularity of the dots is not so noticeable. In addition, since yellow ink has high brightness, the graininess is not so noticeable in the bright part of the image. Therefore, for yellow and black, the print quality does not change much without using dark and light inks. On the other hand, since dark and light inks are mounted, there is a demerit such as an increase in the size of the head, an increase in the size of the recording apparatus, or an increase in cost. Therefore, yellow and black are preferably not provided with dark and light inks.

  The recording head according to the present invention arranges dark and light ink discharge port arrays in the sub-scanning direction, and also arranges two or more discharge port arrays not using dark and light inks in the sub-scanning direction in the same manner as the discharge port arrays having dark and light inks. By doing so, it is possible to arrange the ejection port arrays so as to reduce the width of the recording head. Therefore, the size of the head cartridge and the recording apparatus main body can be reduced by reducing the width of the recording head. In the example, the dark and light ink discharge port arrays are arranged in the sub-scanning direction. However, the dark and light ink discharge port arrays may be arranged in the main scanning direction, and cyan and magenta may be arranged in the sub-scanning direction.

  Further, the blur at the boundary between two colors on the recording medium is most likely to occur when the combination of yellow and black is generated, or the contrast difference is most noticeable. In the present invention, since the yellow and black ejection port arrays are arranged in the sub-scanning direction, the printing of the recording head differs between yellow printing and black printing at a certain position on the recording medium. Therefore, there is a time difference between the yellow print and the black print by the scan time of the recording head. Depending on the time, the next ink is printed after the previously printed ink has penetrated and fixed to the recording medium or dried to some extent. As a result, boundary bleeding is reduced.

2 and 3 are diagrams schematically showing main portions of the first and second modified examples of the recording head according to the first embodiment, and are views of the surface on which the recording head is formed as viewed from the outside of the ejection opening. .
In the recording head of Example 1, the arrangement of the ejection port arrays for the respective ink colors is black (Bk) on the same side as the ejection port array for light magenta (LM) and light cyan (LC) as shown in FIG. (Y), dark magenta (M), and dark cyan (C) can be brought to the same side as the ejection port array. Further, the arrangement shown in FIG. 3 is possible without arranging the discharge ports of the respective colors in a staggered arrangement.

  As described above, yellow and black are likely to bleed on the print surface and the bleed is noticeable. However, the bleed is likely to occur or is conspicuous at the boundary between the dots where the dots are applied without any gap, that is, the so-called solid-coated portion. In particular, bleeding is conspicuous at the border with black, and in general, there are many combinations of black and other colors in documents and graphic images. The light ink is originally not used so much in the solid coating portion. Therefore, blurring is conspicuous after the combination of black and yellow is a combination of black and dark ink, that is, a combination of black and dark magenta and dark cyan. In the ejection port array shown in FIG. 1A, the ejection port arrays 21Bk and 22Bk that eject black ink do not overlap the ejection port arrays 21M, 22M, 21C, and 22C that eject dark ink in the main scanning direction. It has become the arrangement. For this reason, yellow, dark magenta, and dark cyan inks have a time difference corresponding to the scan in the main scanning direction of the recording head, which is superior to the arrangement of FIG. 2 as a countermeasure against such blurring.

FIG. 4 schematically shows the main part of the recording head according to the second embodiment of the present invention, and is a view of the surface of the recording head on which the discharge port is formed as viewed from the outside of the discharge port. FIG. It is sectional drawing of a direction.
In the recording head of Example 2, as shown in FIGS. 4 and 5, dark and light cyan (C, LC) is used for the outermost discharge port arrays 24 and 34, and light and magenta (M, LM) is used for the discharge port arrays 25 and 35. ) In the innermost discharge port arrays 26 and 36 that discharge yellow (Y) and black (Bk). Therefore, yellow ink and black ink are supplied to the two ink supply ports 9 provided in the central portion, light and dark magenta inks are supplied to the four ink supply ports adjacent to the central ink supply port, and the four outermost ink supplies are supplied. Dark and light cyan inks are respectively supplied from the ink tanks to the mouths. As described above, the central ink supply port supplies liquid to the two ejection port arrays 26 and 36, and the two central ink supply ports and the liquid flow path are respectively provided in the ejection port arrays 26 and 36. Functions as a common liquid chamber.

  As described above, the two adjacent ejection port row groups are each provided with an ejection port row that ejects the same type of liquid in adjacent rows, and the other ejection port rows and their drive circuits are omitted from the central portion. By arranging them symmetrically, it is possible to arrange through holes as ink supply ports, drive circuits, heating resistance elements and the like at equal intervals with respect to the substrate without waste. In this embodiment, the size of one heating resistor element 2 is 30 μm × 30 μm, the width of the ejection port, drive circuit and wiring is 1.2 mm, and the width of the upper surface of the substrate of the ink supply port is 0.2 mm. The width size can be 1.2 × 6 + 0.2 × 5 = 8.2 mm.

  Furthermore, in the recording head of Example 2, as is apparent from FIG. 4, the first ejection port array group 27 and the second ejection port array group 37 are ejection ports that form respective ejection port array groups. The discharge ports in the rows 24 to 26 and 34 to 36 are arranged so as to be shifted in the arrangement direction of the discharge ports so as to complement each other in the main scanning direction of the recording head. As shown in FIG. 4, in this embodiment, each of the discharge port arrays 24-26 and 34-36 forming the first discharge port array group 27 and the second discharge port array group 37 has 128 pieces of each color. There are a total of 256 discharge ports in a row with a pitch of about 42 μm pitch (1/600 inch). In the ejection port array group 27 and the ejection port array group 37, the arrangement is exactly the ejection port array with respect to the sub-scanning direction of the recording head (in the present embodiment, it coincides with the arrangement direction of the ejection port arrays). The pitch is shifted by half (about 21 μm).

First, a description will be given of the merit of the arrangement of the ejection port array of each color with respect to the center in the recording head of the second embodiment.
FIG. 6 is a diagram for explaining an example of a recording method by the recording head according to the second embodiment.
Here, when printing a primary color, for example, a single magenta color, a single droplet is ejected from the ejection port array 25 and the ejection port array 35 to the dot positions d1 and d2, respectively, regardless of the scanning direction. To form an image. In this case, since the same color, the difference in coloring due to the order of printing does not appear.

On the other hand, in order to print a secondary color, for example, blue as shown in FIG. 6, the discharge port array 24 (cyan), the discharge port array 25 (magenta), and the discharge port array 34 (cyan) for one pixel. Then, one droplet is ejected from each of the ejection port arrays 35 (magenta) to form an image.
When recording in the forward direction, the liquid droplets pass through a predetermined position of the recording medium in the order of the ejection port array of C1, M1, M2, and C2, so that the liquid droplets are in the order shown in FIGS. Reaches the recording medium. Here, at the dot position d1, since the droplets have landed in the order of C → Y, the coloration of cyan that has landed first becomes dominant. On the other hand, at the dot position d2, since the droplets have landed in the order of M → C, the color of magenta that has landed first becomes dominant.

When recording in the backward direction, the recording medium passes through a predetermined position of the recording medium in the order of C2->M2->M1-> C1, and in the order shown in FIGS. 6 (e) to (h). The droplets land on the recording medium. Here, at the dot position d1, since the droplets have landed in the order of M → C, the color of magenta that has landed first becomes dominant. On the other hand, at the dot position d2, since the droplets have landed in the order of C → M, the color of cyan that has landed first becomes dominant.
In this way, a dot having a dominant cyan color and a dot having a dominant magenta color are always used in pairs regardless of the scanning direction, so that this pixel has an intermediate blue color.

FIG. 7 is a diagram illustrating a state in which the dot positions d1 and d2 overlap.
Actually, as shown in FIG. 7, since the dot positions d1 and d2 are overlapped, as the driving (applying) order, the forward path is a cyan dot from C1, a magenta dot from M1, and from M2. Magenta dots, cyan dots from C2, and cyan dots from C2, magenta dots from M2, magenta dots from M1, and cyan dots from C1 on the return path. In this way, the firing order is symmetrical, in other words, the ink deposition order is the same, so that blue color development can be expressed uniformly. Therefore, the occurrence of color unevenness due to reciprocal printing can be prevented.
Other color combinations and light ink can also prevent occurrence of color unevenness due to reciprocal printing in the same manner as described above.

The recording method described above is one of the methods suitable for performing reciprocal printing using the liquid discharge head of the present invention, and the image forming method using the liquid discharge head of the present invention is the recording mode described above. It is not limited to only.
Thus, by arranging colors symmetrically with respect to the center, color unevenness due to reciprocal printing can be prevented, and high-speed printing by reciprocating printing can be performed with high image quality.

  In the recording head according to the first embodiment shown in FIG. 1, the ink supply port 9 and the common liquid chamber 11 correspond to the two ejection port arrays. 4 and 5, the ink supply port 9 and the common liquid chamber 11 correspond to only one ejection port row except for the central ejection port rows 26 and 36. Therefore, the width of the head is required for the ink supply port and the common liquid chamber as compared with the configuration shown in FIG. In the recording head according to the present invention, the discharge port arrays of the dark and light inks and the yellow and black inks are arranged in the main scanning direction, so that the color of the discharge port array is arranged symmetrically with respect to the center in order to prevent color unevenness in reciprocal printing. However, the expansion of the width of the recording head can be reduced.

FIG. 8 is a diagram schematically illustrating a main part of a modified example of the recording head according to the second embodiment, and FIG. 8A is a view of the surface on which the ejection port of the modified example 1 is formed as viewed from the outside of the ejection port. FIG. 8B is a view of the surface on which the discharge port of Modification 2 is formed as viewed from the outside of the discharge port.
In the recording head of Example 2, it is not always necessary to arrange the ejection port arrays for ejecting dark and light inks in the sub-scanning direction, and the ejection port arrays for ejecting dark and light inks are arranged in the main scanning direction as shown in FIG. Even so, the object of the present invention can be achieved.
Further, it is not necessary to arrange the ejection port arrays for ejecting inks (yellow and black in this embodiment) that do not necessarily have dark and light inks in a straight line, and an arrangement as shown in FIG.

FIG. 9 is a diagram schematically illustrating the main part of the recording head of Example 3. FIG. 9A is a view of the surface on which the discharge port of the modification is formed as viewed from the outside of the discharge port, and FIG. It is the figure which looked at the surface in which the discharge outlet of the modification was formed from the discharge outlet outer side.
In the recording head of Example 3, the discharge port arrays of four colors of dark and light magenta (M, LM) and dark and light cyan (C, LC) are arranged in the sub-scanning direction, and yellow (Y) and black (Bk) are arranged. Similarly, it is arranged in the sub-scanning direction, and the black (Bk) ejection port array is elongated. The number of discharge ports for yellow (Y), dark and light magenta (M, LM), and dark and light cyan (C, LC) is the same, and the discharge port is increased only for black (Bk). For example, the number of discharge ports in one row of yellow (Y), dark and light magenta (M, LM), and light and light cyan (C, LC) is 64, and the number of discharge ports in one row of black (Bk) is 192. The entire recording head is provided with 1024 ejection ports. In the recording head of Example 3, since the four color ejection port arrays are arranged in the sub-scanning direction, the number of columns in the main scanning direction can be reduced, and the head width can be reduced. Therefore, it is particularly effective for a portable printer or the like that needs to reduce the size of the entire recording apparatus. Further, since the number of black discharge ports is relatively large, the printing speed of a document image with a lot of black ink can be increased. Although the discharge port array arrangement of the present embodiment has been exemplified as FIGS. 9A and 9B, it is not limited to such an arrangement.

  In the recording heads of Examples 1 to 3, the thermal ink jet method in which liquid such as ink is ejected from the ejection port using the pressure of bubbles generated by film boiling due to thermal energy is taken as an example, but the ejection principle is limited to this. However, the present invention can be similarly applied to a piezoelectric type in which liquid is discharged using displacement of a piezoelectric element, an electrostatic type in which a diaphragm is displaced by electrostatic force, and liquid is discharged by a restoring force of the vibration plate.

FIG. 10 is a perspective view showing a head cartridge according to Embodiment 4 of the present invention.
The head cartridge 41 according to the fourth embodiment is a head cartridge in which the recording head 42 according to any one of the first to third embodiments and a liquid container that holds the liquid supplied to the recording head 42 are integrated. Since the recording head 42 can be formed in a small size, the head cartridge 41 can also be reduced in size.

Next, an example of an ink jet recording apparatus equipped with the recording head of the present invention will be described.
FIG. 11 is a perspective view of a main part showing an ink jet recording apparatus according to a fifth embodiment of the present invention, and FIG. 12 is a side view of a mechanism part of the recording apparatus.
In the ink jet recording apparatus of the fifth embodiment, a carriage 63 that can move in the main scanning direction inside the recording apparatus main body 51, a recording head 64 that is an ink jet head that implements the present invention mounted on the carriage, and supplies ink to the recording head. A paper feed cassette (or a paper feed tray) 54 that accommodates a printing mechanism 52 formed of an ink cartridge or the like and can stack a large number of sheets 53 from the front side in the lower part of the recording apparatus main body 51. Can be removably mounted, the manual feed tray 55 for manually feeding the paper 53 can be opened, and the paper 53 fed from the paper feed cassette 54 or the manual feed tray 55 is taken in. Then, after a required image is recorded by the printing mechanism unit 52, the image is discharged to a discharge tray 56 mounted on the rear side.

  The printing mechanism 52 holds the carriage 63 slidably in the main scanning direction (in the direction perpendicular to the paper in FIG. 12) with a main guide rod 61 and a sub guide rod 62 which are guide members horizontally mounted on left and right side plates (not shown). According to the present invention, yellow (Y), cyan (C), light cyan (LC), magenta (M), light magenta (LM), and black (Bk) ink droplets are ejected onto the carriage 63. A recording head 64 composed of an ink jet head is mounted with a plurality of ink ejection openings (nozzles) arranged in a direction intersecting the main scanning direction and the ink droplet ejection direction facing downward. In addition, each ink cartridge 65 for supplying ink of each color to the recording head 64 is replaceably mounted on the carriage 63.

  The ink cartridge 65 has an air opening communicating with the atmosphere upward, a supply opening supplying ink to the inkjet head below, and a porous body filled with ink inside, and the capillary force of the porous body. Thus, the ink supplied to the inkjet head is maintained at a slight negative pressure. Further, although the recording head 64 of each color is used here as the recording head, a single head having nozzles for ejecting ink droplets of each color may be used.

  Here, the carriage 63 is slidably fitted to the main guide rod 61 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the secondary guide rod 62 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 63 in the main scanning direction, a timing belt 70 is stretched between a driving pulley 68 and a driven pulley 69 that are rotationally driven by a main scanning motor 67, and the timing belt 70 is moved to the carriage 63. The carriage 63 is reciprocally driven by forward and reverse rotations of the main scanning motor 67.

  On the other hand, in order to convey the paper 53 set in the paper feeding cassette 54 to the lower side of the recording head 64, the paper feeding roller 71 and the friction pad 72 for separating and feeding the paper 53 from the paper feeding cassette 54 and the paper 53 are guided. A guide member 73 for conveying, a conveyance roller 74 for reversing and conveying the fed paper 53, a conveyance roller 75 pressed against the peripheral surface of the conveyance roller 74, and a feeding angle of the paper 53 from the conveyance roller 74 are defined. A tip roller 76 is provided. The transport roller 74 is rotationally driven by a sub-scanning motor 77 through a gear train.

  A printing receiving member 79 is provided as a paper guide member for guiding the paper 53 fed from the transport roller 74 below the recording head 64 corresponding to the range of movement of the carriage 63 in the main scanning direction. A conveyance roller 81 and a spur 82 that are rotationally driven to send the paper 53 in the paper discharge direction are provided downstream of the printing receiving member 79 in the paper conveyance direction. A roller 83 and a spur 84, and guide members 85 and 86 that form a paper discharge path are disposed.

  At the time of recording, the recording head 64 is driven according to the image signal while moving the carriage 63, thereby ejecting ink onto the stopped paper 53 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 53 reaches the recording area, the recording operation is terminated and the paper 53 is discharged.

  In addition, a recovery device 87 for recovering defective ejection of the recording head 64 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 63. The recovery device 87 includes a cap unit, a suction unit, and a cleaning unit. The carriage 63 is moved to the recovery device 87 side during printing standby, and the recording head 64 is capped by the capping means, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When a discharge failure occurs, the discharge port (nozzle) of the recording head 64 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with a suction unit through the tube. Etc. are removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, since this inkjet recording apparatus is equipped with the inkjet head embodying the present invention, an image having a good gradation with little graininess can be obtained, the printing speed is high, and the inkjet recording apparatus is small. It is feasible.

1A and 1B are diagrams schematically illustrating a main part of a recording head according to a first exemplary embodiment of the present invention, in which FIG. 1A is a view of a surface on which a discharge port of the recording head is formed viewed from the outside of the discharge port, and FIG. FIG. 1C is a partially enlarged view of the exit portion, and FIG. 1C is a cross-sectional view in the main scanning direction of the recording head of FIG. FIG. 6 is a diagram schematically illustrating a main part of Modification 1 of the recording head of Example 1, and is a view of the surface of the recording head on which the ejection port is formed as viewed from the outside of the ejection port. FIG. 6 is a diagram schematically illustrating a main part of a second modification of the recording head of Example 1, and is a view of the surface of the recording head on which the ejection port is formed as viewed from the outside of the ejection port. FIG. 6 is a diagram schematically illustrating a main part of a recording head of Example 2, and is a diagram of a surface of the recording head on which an ejection port is formed as viewed from the outside of the ejection port. It is sectional drawing of the main scanning direction of FIG. FIG. 10 is a diagram for explaining an example of a recording method by a recording head of Example 2. It is a figure which shows a mode that dot position d1, d2 has overlapped. FIG. 8A is a diagram schematically illustrating a main part of a modified example of the recording head according to the second embodiment, and FIG. 8A is a view of the surface on which the discharge port of the first modified example is formed as viewed from the outside of the discharge port, and FIG. These are the figures which looked at the surface in which the discharge outlet of the modification 2 was formed from the discharge outlet outer side. FIGS. 9A and 9B are diagrams schematically illustrating a main part of the recording head according to the third embodiment. FIG. 9A is a view of the surface on which the discharge port is formed as viewed from the outside of the discharge port, and FIG. It is the figure which looked at the done surface from the discharge outlet outer side. FIG. 6 is a perspective view showing a head cartridge of Example 4. FIG. 9 is a perspective view illustrating a main part of an ink jet recording apparatus according to a fifth embodiment. It is a side view of the mechanism part of the inkjet recording device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Recording head, 2 ... Heat generation resistance element (energy conversion element), 3 ... Board | substrate, 4 ... Discharge port, 5 ... Orifice plate, 6 ... Drive circuit, 7 ... Contact pad, 8 ... Wiring, 9 ... Ink supply port, DESCRIPTION OF SYMBOLS 10 ... Liquid flow path, 11 ... Common liquid chamber, 21Y, 22Y, 21M, 22M, 21C, 22C, 21Bk, 22Bk, 21LM, 22LM, 21LC, 22LC ... Discharge port row, 24-26 ... First discharge port row , 27: First ejection port array group, 34 to 36: Second ejection port array, 37: Second ejection port array group, 41: Head cartridge, 42: Recording head, 51: Recording device main body, 52 ... Printing mechanism 53, paper, 54, paper feed cassette, 55 ... manual feed tray, 56 ... paper discharge tray, 61 ... main guide rod, 62 ... sub guide rod, 63 ... carriage, 64 ... recording head, 65 ... ink car Ridge, 67 ... main scanning motor, 68 ... drive pulley, 69 ... driven pulley, 70 ... timing belt, 71 ... paper feed roller, 72 ... friction pad, 73 ... guide member, 74 ... transport roller, 75 ... transport roller, 76 DESCRIPTION OF SYMBOLS ... Tip roller, 77 ... Sub-scanning motor, 79 ... Printing receiving member, 81 ... Conveyance roller, 82 ... Spur, 83 ... Discharge roller, 84 ... Spur, 85, 86 ... Guide member, 87 ... Recovery device.

Claims (7)

  A recording head having a plurality of discharge ports for discharging ink, and a discharge port array including a plurality of discharge port arrays for discharging dark ink having a relatively high density of similar colors, and a light ink having a relatively low concentration An ejection port array comprising a plurality of ejection port arrays for ejecting ink, and an ejection port array comprising a plurality of ejection port arrays for ejecting ink not having light and shade, and having two or more colors without ink. A recording head having two or more ejection port arrays arranged in a scanning direction, wherein at least two ejection port arrays for ejecting the ink having no density are arranged in a sub scanning direction.   The recording head according to claim 1, wherein the ink having no shading is a black ink and a yellow ink.   The recording head according to claim 2, wherein the ejection port array that ejects the black ink does not overlap with the ejection port array that ejects the dark ink in the main scanning direction.   The recording head according to claim 1, wherein the ejection port array is arranged so that the color of the ink ejected from the ejection port array is symmetrical in the main scanning direction. .   5. The recording according to claim 4, wherein the ejection port array at the center of symmetry of the ejection port arrays arranged so as to be symmetric in the main scanning direction is an ejection port array that ejects black ink and yellow ink. head.   A head cartridge in which an ink jet head for ejecting ink droplets and an ink tank for supplying ink to the ink jet head are integrated, wherein the ink jet head is the recording head according to any one of claims 1 to 5. Head cartridge to be used.   An ink jet recording apparatus equipped with an ink jet head for discharging ink droplets, wherein the ink jet head is the recording head according to any one of claims 1 to 5 or the head cartridge according to claim 6. apparatus.

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