JP3870120B2 - Inkjet recording head and inkjet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording head and an ink jet recording apparatus including the ink jet recording head, and more particularly to a structure in an ink flow path in an ink jet recording head that discharges ink of different droplet sizes of the same color. Specifically, two or more different size droplets are ejected in a head chip that ejects ink of the same color and has at least one or more rows of ink ejection ports arranged in a row. The present invention relates to an ink jet recording head having a configuration in which discharge ports to be mixed are mixed.
[0002]
[Prior art]
Color ink jet printers using thermal ink jet technology have increased in resolution year by year, and in particular, in the recording head used to form the image quality, the resolution of the ejection port array for ejecting individual liquid droplets has increased to 600 dpi and 1200 dpi year by year. The resolution is increasing.
[0003]
Further, regarding the size of the ejected ink droplets forming the image, 15 pl is particularly used for a recording head that ejects color ink in order to reduce graininess in a grayscale halftone portion, a halftone in a color photo image, and a highlight portion. From the degree, it tends to be a droplet of 5 pl and 2 pl every year.
[0004]
However, for small droplets and high-resolution recording heads, high-quality color graphic images and photo image printouts can meet high-quality user needs, but resolution such as monochrome text printing and color graphs in forms For the rough image print output that is not required, because of the small droplets and high resolution, the image output data is enlarged and requires a lot of data transfer time. Become.
[0005]
In order to improve this, the applicant of the present application has arranged a large droplet size and high frequency recording head of about 30 pl for the recording head for monochrome printing, which has a high demand for high-speed printing, and the recording head for color ink. We have devised and commercialized a means for arranging a small liquid droplet of about 5 pl and a high-frequency recording head.
[0006]
[Problems to be solved by the invention]
However, even for color images, high-definition image data, such as when printing image data that does not require a relatively high resolution, such as a form graph, and digital photo images of digital input device data using a digital camera, color scanner, etc. When printing data, the print output data size, data processing time, data transfer time, and memory buffer capacity on the recording device are taken into account. It is desirable to be able to form an image, and in the case of high-quality printing, since it is desirable to reduce the granularity of the formed image as much as possible with droplets of an extremely small size, a recording element of the same color in a color ink jet recording head Drop different size droplets on the base (also called recording chip) It is desirable to modulate the droplet size.
[0007]
In order to realize this, the applicant of the present invention disclosed in JP-A-8-183179, heaters of different sizes are arranged in the same nozzle (ink flow path communicating with the ink discharge port), and the individual heaters are arranged. A means for ejecting droplets of different sizes from the same nozzle has been devised and commercialized by properly using foaming.
[0008]
In addition, if a recording head that simply needs a different amount of discharge amount is realized, a single discharge port array (also referred to as a nozzle array) that can discharge droplets of different sizes is recorded. It is conceivable to arrange a plurality of colors per color on the head.
[0009]
However, in the former, since droplets of different sizes are ejected from the same nozzle, the ink supply speed (refill speed) from the ink supply source to the ink flow path varies depending on the size of the liquid droplets. Therefore, in a so-called serial type recording apparatus that performs recording while moving (scanning) the inkjet recording head relative to the recording sheet, it is difficult to eject droplets of different sizes during the same recording head scan, It is necessary to separately eject droplets of different sizes such as large and small by performing reciprocation of the recording head a plurality of times. This means that it is difficult to control droplet size modulation in forming a high-definition image because droplets of different sizes cannot be ejected at the same drive frequency.
[0010]
Further, the latter is difficult to achieve in terms of cost in the market for ink jet printers where the price has been significantly reduced.
[0011]
The present invention has been made in view of such problems, and a first object is to eject at least two different sizes of liquid droplets in the same color ink ejection port array of an inkjet recording head, Another object of the present invention is to provide an inexpensive ink jet recording head capable of modulating the droplet size by adjusting the discharge frequencies equally, and an ink jet recording apparatus including the ink jet recording head.
[0012]
In addition, the inventors of the present applicant have ejected two rows of ejecting ink of the same color in order to eject different size droplets on the same color printing element base and modulate the droplet size per color. An outlet row (nozzle row) is arranged so as to sandwich an ink supply port and a common liquid chamber that supplies ink to the ink flow path for each discharge port, and each discharge port is changed by changing the opening diameter of the discharge port in each row. A configuration has been devised in which the size of the ejected ink droplets from the rows is different. However, this configuration may cause the following problems.
[0013]
To reduce the cost of the recording head, the size of the recording element substrate is reduced, and the opening area of the ink supply port (ink common liquid chamber) that supplies ink into the ink flow path for each ejection port is reduced. A crosstalk phenomenon in which the discharge operation at one nozzle interferes with the ink of another nozzle and the discharge of the ink is disturbed even though the ink is discharged at the set discharge frequency in the continuous discharge of different droplet sizes. In particular, it appeared remarkably at the discharge port with a small droplet size.
[0014]
This crosstalk phenomenon can be avoided by widening the opening area of the ink common liquid chamber and the ink supply port, but it becomes impossible to provide an ink jet recording head that can discharge droplets of different sizes with the same color recording chip at low cost. .
[0015]
When this phenomenon is observed, it has been found that the phenomenon becomes more prominent as the plurality of ink discharge ports arranged in the nozzle row are continuously driven. In addition, the crosstalk phenomenon is transmitted to the common liquid chamber that supplies ink and the ink supply port when pressure waves are generated by the heat of the electrothermal transducer when the ink is discharged from the ink discharge port. This occurs due to interference with the ink flow to the other ink ejection ports. As the ink is simultaneously ejected from the plurality of ink ejection ports, the interference of the pressure wave in the common liquid chamber and the ink supply port increases. This also causes the phenomenon of pushing out to the outside of the discharge port surface (overshoot).
[0016]
In addition, the pressure wave was increased as the ink was ejected in a large droplet size to generate a large bubble, and a large ink overshoot was confirmed at the ejection port having a small droplet size where ink was not ejected.
[0017]
Accordingly, a second object of the present invention is to apply pressure in the common liquid chamber and the ink supply port when discharging ink in different ink discharge port arrays of the same color inkjet recording head sharing the ink supply port. Inkjet recording that can realize stable discharge of different droplets by suppressing the crosstalk phenomenon caused by wave interference and suppressing the ink meniscus overshoot due to the crosstalk phenomenon, especially at the discharge port with a small droplet size The present invention is to provide a head and an ink jet recording apparatus including the ink jet recording head at low cost.
[0018]
[Means for Solving the Problems]
  To achieve the above object, the present invention provides a plurality of ejection openings for ejecting droplets.WhenA liquid chamber for storing a liquid to be supplied to each discharge port, a supply port for supplying the liquid into the liquid chamber, a plurality of flow paths communicating the discharge ports and the liquid chamber, and the flow A flow path wall forming a path;A filter structure composed of columns between each flow path and the supply port;A discharge energy generating element for applying discharge energy to the liquid in the flow path;TheIn an inkjet recording head comprising:
  The plurality of discharge ports include a first discharge port that discharges a droplet having a predetermined size, and a second discharge port that discharges a liquid suitable for a liquid larger than the droplet discharged from the first discharge port. With
  The filter structure includes a first filter structure provided corresponding to the flow path including the first discharge port, and a second filter provided corresponding to the flow path including the second discharge port. A structure,
  The path that communicates between the supply port and each flow path is divided into a plurality by the filter structure and the flow path wall,
  Due to the first and second filter structures, the flow resistance between the flow path including the first discharge port and the supply port is between the flow path including the second discharge port and the supply port. Greater than the flow resistance ofIt is characterized by that.
[0019]
  In the invention as described above,In a configuration in which at least two droplet sizes discharged from a plurality of discharge ports are mixed, the first and second filter structures cause a flow resistance between the flow path including the first discharge port and the supply port. Is larger than the flow resistance between the flow path provided with the second discharge port and the supply port, so that the discharge frequency is set for each of the first and second discharge ports having different droplet sizes to be discharged. It becomes possible to adjust.
[0020]
The adjustment of the ejection frequency described here refers to the recording in the row direction by moving (scanning) the recording head relative to the recording sheet, in using the inkjet recording head in a so-called serial recording method. This means that when performing simultaneous ejection of droplets of different sizes within a single scan of the recording head, it is necessary to equalize the ejection frequency so as not to cause image defects such as missing droplets. We believe that it is desirable that the variation in the discharge frequency that does not reach is ± 20% or less. The discharge frequency is the same in the column of the embodiment of the invention, but means a cycle in which the liquid in the flow path is discharged from the discharge port and the liquid is again filled in the flow path.
[0021]
  The present invention also provides:The inkjet recording head includes a first ejection port array including a plurality of the first ejection ports and a second ejection port array including a plurality of the second ejection ports, and the first and second This includes a configuration in which two rows of the discharge ports are arranged so as to sandwich the supply port. In the case of such a head configuration, the vibration of the liquid due to the pressure wave in the liquid chamber and the supply port, which is generated when droplets having different sizes are discharged, is generated in the flow path corresponding to the discharge port having a small droplet size. The liquid is not affected, and droplets of different sizes can be stably discharged from discharge port arrays having different droplet sizes sharing the same supply port.
[0023]
Furthermore, in the ink jet recording head of each of the above inventions, the filter structure is disposed between a column cross-sectional area, the number of columns, or between each flow path and the supply port according to the droplet size to be ejected. Since the positions of the columns are different, it is possible to adjust the ink flow resistance that passes through each of the flow paths having different droplet sizes to be ejected.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
First, before specifically describing the features of the present invention, an ink jet recording head capable of suitably carrying out the present invention and a configuration of an ink jet recording apparatus suitable for mounting the recording head will be described.
[0026]
FIG. 1 is a schematic view of the vicinity of an ejection port of a recording head (also referred to as a recording chip) that ejects a single color ink in an ink jet recording head that preferably implements the present invention. FIG. (B) shows the AA 'line sectional view of (a).
[0027]
In the recording head of the form shown in FIG. 1A, an ink discharge port 2, an ink flow path 8, and an ink liquid chamber 12 are formed on a substrate 4, which is a space using a mold resin 6 as a wall material. The mold resin 6 also serves as an orifice plate portion 11 that forms the ink discharge port 2. An ink supply port 3 opened in the substrate 4 communicates with the ink liquid chamber 12.
[0028]
The ink flow path 8 is a portion that stores ink that is a recording liquid to be ejected, and ink is replenished from the ink supply port 3 through the ink liquid chamber 12. The ink discharge port 2 and the ink supply port 3 are communicated with each other through an ink liquid chamber 12 and an ink flow path 8.
[0029]
The ink flow path 8 is partitioned by the wall 5 of the mold resin 6. The ink in the ink flow path 8 ejects ink as droplets from the ink ejection port 2 in accordance with the ejection energy applied from the electric heat generating element 1 for generating ink ejection energy.
[0030]
A filter 10 for filtering ink is provided in each ink liquid chamber 12 between the ink supply port 3 side opening (ink inlet / outlet) of each ink flow path 8 and the ink supply port 3. The filter 10 has a columnar structure arranged with respect to the opening of each ink flow path 8 on the ink supply port 3 side.
[0031]
In the form shown in this figure, the columnar filter 10 is a column that extends from the floor surface of the ink liquid chamber 12 to the ceiling surface. Here, the width of the space between the column and the column and the column and the ink flow path wall (opening diameter of the filter structure) is set to be equal to or smaller than the width of the ink flow path 8 (interval of the ink flow path wall). With the filter having such a structure, even if dust or the like is contained in the ink replenished from the ink supply port 3, an effect of preventing the inflow of dust or the like into the ink flow path 8 is produced.
[0032]
Next, an ink jet recording apparatus equipped with the ink jet recording head having the above configuration will be described.
[0033]
FIG. 2 is a diagram showing a main configuration of an example of an ink jet recording apparatus equipped with the ink jet recording head of the present invention.
[0034]
In the ink jet recording apparatus shown in FIG. 2, four color ink tanks 22 of K (black), C (cyan), M (magenta), and Y (yellow) are detachably mounted, and ink of each color is formed into a sheet form. The recording head 21 is provided for performing recording by discharging to the recording medium 25. The recording head 21 is connected to a part of a driving belt 24 that transmits the driving force of the driving motor 23, and is guided by a guide shaft to enable reciprocal movement. Recording is performed by ejecting ink droplets from the ejection port (not shown) of the recording head 21 to the recording medium 25 while reciprocating the recording head 21 while keeping a slight gap with respect to the recording medium 25. Is called.
[0035]
In FIG. 2, the recording medium 25 is transported in a direction (preferably a perpendicular direction) intersecting the moving direction of the recording head 21 by the paper feed transport mechanism 26. An image is formed over the entire area of the recording medium 25 by repeating the recording operation of conveying the recording medium 25 by a predetermined amount every time recording for one line and recording the next line again.
[0036]
At a predetermined position (for example, home position) within the reciprocal range of the recording head 21 and out of the recording area, a surface (discharge port forming surface) on which a plurality of discharge ports of the recording head 21 are formed is capped, and each discharge By forcibly sucking and discharging ink from the outlet, a suction recovery cap 27 is arranged to remove foreign matters such as thickened ink, fixed ink, dust, and bubbles in each discharge port, and to restore the discharge function normally. It is installed. The suction recovery cap 27 capping the ejection port forming surface of the recording head 21 to prevent ink from evaporating from the ejection port during non-recording.
[0037]
A rubber-like elastic wiper blade 28 made of urethane rubber or the like is provided near the position where the suction recovery cap 27 is installed. The wiper blade 28 usually stands by in a place where it does not interfere with the reciprocating direction of the recording head 21 or is moved back and forth (recording medium in FIG. 2) by a motor or the like (not shown) provided in the ink jet recording apparatus when wiping is performed. It is configured to move in a direction substantially parallel to the transport direction and wipe off foreign matters such as ink liquid, dust, dust, and paper dust adhering to the ejection port forming surface of the recording head 21 at a predetermined position.
[0038]
In configuring a recording head for outputting a color image in a so-called serial type ink jet recording apparatus in which the ink jet recording head is reciprocated in a direction intersecting the recording medium conveyance direction as described above, A direction perpendicular to the arrangement direction of the nozzle rows in which the components in the vicinity of the recording head ejection openings shown in FIG. To place.
[0039]
FIG. 3 is a perspective view from the discharge port forming surface side of the recording head 21 shown in FIG. As shown in this figure, the recording head 21 has two recording chips 34 on the surface facing the recording medium (reference numeral 25 in FIG. 2), and one recording chip ejects K (black) ink. Are arranged in a row in a direction crossing the reciprocating direction of the recording head 21. In the other recording chip, ejection ports for ejecting inks of C (cyan), M (magenta), and Y (yellow) are arranged in a line in a direction crossing the reciprocating direction of the recording head 21. In addition, the ejection port arrays corresponding to the respective colors are arranged in parallel.
[0040]
Further, the ink jet recording head of the present invention illustrated in FIG. 1 has an ink discharge port capable of discharging different small and large droplet sizes, and an ink flow path configuration connected to each ink discharge port, and image information to be recorded. Accordingly, an electric pulse can be selectively applied to the electrothermal conversion element of the ink flow path that can eject a desired droplet size.
[0041]
Possible combinations of different droplet sizes are 15pl and 8pl, 8pl and 4pl, or 5pl and 2pl, etc., but the composition of different droplet sizes is close to an integral multiple of the minimum droplet size. It is desirable to configure with a combination of ink droplet volumes.
[0042]
Accordingly, in solving the above-described problems of the present invention, an ink jet recording head having the same shape of the ink flow path connected to the ink discharge port capable of discharging different large and small droplet sizes, as shown in FIG. Focusing on a simple columnar filter 10, the configuration of the filter was changed according to the ink flow path of the ink discharge port for discharging different droplet sizes.
[0043]
The characteristic configuration of the present invention will be described with reference to a plurality of embodiments.
[0044]
(First embodiment)
FIG. 4 is a plan view showing a discharge port forming surface of the ink jet recording head in the first embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and different configurations from those in FIG. 1 will be mainly described.
[0045]
In the ink jet recording head shown in this figure, there are discharge ports for discharging two large and small droplet sizes, that is, a discharge port 51 having a large droplet size and a discharge port 52 having a small droplet size smaller than the discharge port 51. They are alternately arranged to constitute one discharge port array. Further, the two ejection port arrays configured as described above are arranged in parallel so as to sandwich the ink supply port 3, and the ejection ports of each row are arranged at positions shifted from each other by ½ of the ink flow path width. ing.
[0046]
Between the ink supply port 3 side opening (ink inlet / outlet) of the ink flow path 8 and the ink supply port 3, one filter 53 or 54 constituted by a column is arranged for each ink flow path. The filter 53 or 54 is formed in the same manner as the filter 10 shown in FIG. 1 and produces the same effect.
[0047]
The filters 53 and 54 branch the ink flow into a plurality of ink supply paths such as arrows 55 and 56 shown between the ink supply port 3 and the ink flow path 8.
[0048]
Here, as a characteristic feature, the cross-sectional area of the filter 53 corresponding to the discharge port 51 having a large droplet size (or the outer diameter of the column as the filter 53) is the filter corresponding to the discharge port 52 having a small droplet size. It is smaller than the cross-sectional area of 54 (or the outer diameter of the column which is the filter 54).
[0049]
At the location of the filter 53, the width of the space between the column of the filter 53 and the wall of the ink flow path 8 (the opening width of the ink supply path) is wider than the location of the filter 54. The width of the space between the column of the filter 54 and the wall of the ink flow path 8 (opening width of the ink supply path) is smaller than that of the filter 53.
[0050]
As a result, in an ink flow path with a large droplet size and a wide opening width of the ink supply path, the ink flow resistance at the time of ink supply is small, and the ink supply time for the volume in which large ink droplets are ejected is shortened. In an ink flow path with a small droplet size with a narrow opening width of the supply path, the ink flow resistance at the time of ink supply is large, and it is possible to prevent the ink supply time for the volume of ejecting small ink droplets from becoming too fast. Become. As a result, it is possible to adjust the ink supply speed according to the ink discharge ports having different desired droplet sizes.
[0051]
Since the ink supply speed can be adjusted by changing the cross-sectional area of the filter (the outer diameter of the column) according to the ink flow path of the droplet size in this way, the ejection frequency of the ink with different droplet sizes can be adjusted. It is possible to have the same effect.
[0052]
(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment, the ink flow resistance control is characterized in that the filter cross-sectional area is changed for each ink flow path connected to each of the ink discharge ports having different droplet sizes. Furthermore, the ink flow resistance may be controlled by the number of installed filters regardless of the size of the filter cross-sectional area.
[0053]
FIG. 5 is a plan view showing an ejection port forming surface of an ink jet recording head according to the second embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and different configurations from those in FIG. 1 and the first embodiment will be mainly described.
[0054]
As in the first embodiment, the ink jet recording head according to the present embodiment has two ink discharge port arrays, as shown in FIG. Discharge ports 62 having small droplet sizes and small droplet sizes are alternately arranged.
[0055]
Between the ink supply port 3 side opening (ink inlet / outlet) of the ink flow path 8 and the ink supply port 3, a columnar filter 63 or 64 having the same cross-sectional area is disposed. The filter 63 or 64 is formed in the same manner as the filter 10 shown in FIG. 1 and produces the same effect.
[0056]
Here, as a characteristic, the filter 63 corresponding to the ejection port 61 having a large droplet size is one column, whereas the filter 64 corresponding to the ejection port 62 having a small ink droplet is composed of two columns. It consists of pillars. In the present embodiment, the number of columns installed is different for each ink flow path to the ejection port corresponding to each droplet size.
[0057]
As described above, by changing the number of filters installed on the upstream side of the ink flow path to the discharge ports having different droplet sizes, a plurality of arrows 65 and 66 shown between the ink supply port 3 and the ink flow path 8 are provided. Thus, the flow resistance to the ink flow path can be adjusted according to the droplet size. Therefore, it is possible to equalize the ejection frequencies of inks having different droplet sizes.
[0058]
The difference between the present embodiment and the first embodiment is that it is advantageous when configuring a high-resolution recording chip and a high-frequency compatible recording chip that is driven to discharge at a high frequency. For example, when the ink discharge ports are arranged in a row so as to exhibit a resolution of 1200 dpi and an ink flow path leading to each discharge port is formed, a pitch of 1 inch (25.4 mm) / 1200 dpi = 21.1 microns is used. It is necessary to configure the flow path and the flow path wall. Therefore, the filter installation width per one ink flow path is reduced, and when it is desired to increase the ink supply speed from the upstream side of the ink flow path for high frequency, the ink supply port needs to be brought closer to the ink flow path. In addition, the distance from the end of the ink flow path wall to the opening edge of the ink supply port becomes narrow. Therefore, this embodiment is advantageous in that the cross-sectional area of each filter is fixed and the number of filters installed is different in such a narrow space.
[0059]
In addition, this invention is not limited only to the structure mentioned above, What kind of structure may be sufficient if it can achieve this invention. Therefore, according to the cross-sectional area of the filter, the number of filters installed is 1 to 3, 0 to 2 in the ratio of the number of filters corresponding to the ejection port having a large droplet size and the number of filters corresponding to the ejection port having a small ink droplet. It is possible to make them different.
[0060]
(Third embodiment)
Next, a third embodiment of the present invention will be described. The present embodiment also aims to adjust the ink flow resistance of each ink supply path from the ink supply port to the plurality of ink flow paths by the filter configuration as in the first and second embodiments.
[0061]
FIG. 6 is a plan view showing an ejection port forming surface of an ink jet recording head in the third embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the configuration different from FIG. 1 and the first and second embodiments will be mainly described.
[0062]
As in the first embodiment, the ink jet recording head of the present embodiment has two ink discharge port arrays, as shown in FIG. 6, which are more open than the discharge ports 71 having a large droplet size and the discharge ports 71. Discharge ports 72 having small droplet sizes and small droplet sizes are alternately arranged.
[0063]
Between the ink supply port 3 side opening (ink inlet / outlet) of the ink channel 8 and the ink supply port 3, one columnar filter 73 or 74 having the same cross-sectional area is arranged for each ink channel. The filter 73 or 74 is formed in the same manner as the filter 10 shown in FIG. 1 and produces the same effect.
[0064]
Here, as a characteristic feature, the filter 73 corresponding to the discharge port 71 having a large droplet size has an ink supply port at a distance X from the end 5B of the ink flow channel wall to the edge 3B ′ of the ink supply port. It is installed at a position close to the edge 3B ′. On the other hand, the filter 74 corresponding to the discharge port 72 having a small droplet size is close to the end 5B of the ink channel wall at the distance X from the end 5B of the ink channel wall to the edge 3B ′ of the ink supply port. Is installed. In other words, in the present embodiment, the installation position of the columnar filter 73 or 74 is within the range of the distance X from the end 5B of the ink flow path wall on the upstream side of the ink flow path 8 to the edge 3B ′ of the ink supply port. Are different.
[0065]
For this reason, the width of the space between the column of the filter 73 and the wall of the ink flow path 8 (the opening width of the ink supply path) is wider at the location of the filter 73 than at the location of the filter 74. At the location, the width of the space between the column of the filter 74 and the wall of the ink flow path 8 (opening width of the ink supply path) is narrower than the location of the filter 73.
[0066]
As a result, in an ink flow path with a large droplet size and a wide opening width of the ink supply path, the ink flow resistance at the time of ink supply is small, and the ink supply time for the volume in which large ink droplets are ejected is shortened. In an ink flow path with a small droplet size with a narrow opening width of the supply path, the ink flow resistance at the time of ink supply is large, and it is possible to prevent the ink supply time for the volume of ejecting small ink droplets from becoming too fast. Become. As a result, it is possible to adjust the ink supply speed according to the ink discharge ports having different desired droplet sizes.
[0067]
In this way, by changing the filter installation position on the upstream side of the ink flow path to the discharge ports having different droplet sizes, a plurality of arrows 75 and 76 shown between the ink supply port 3 and the ink flow path 8 are provided. Therefore, the flow resistance to the ink flow path can be adjusted according to the droplet size. Therefore, it is possible to equalize the ejection frequencies of inks having different droplet sizes.
[0068]
The difference between this embodiment and the first and second embodiments is that it is advantageous when configuring a high-resolution recording chip. For example, when the ink discharge ports are arranged in a row so as to exhibit a resolution of 1200 dpi and an ink flow path leading to each discharge port is formed, a pitch of 1 inch (25.4 mm) / 1200 dpi = 21.1 microns is used. It is necessary to configure the flow path and the flow path wall. For this reason, the filter installable width per one ink flow path is reduced.
[0069]
Therefore, this embodiment is advantageous in that the cross-sectional area of each filter is fixed and the number of filters installed is different in such a narrow space.
[0070]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
[0071]
FIG. 7 is a plan view showing an ejection port forming surface of an ink jet recording head according to the fourth embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and different configurations from those in FIG. 1 will be mainly described.
[0072]
In the ink jet recording head shown in this figure, there are discharge ports for discharging two large and small droplet sizes, that is, a discharge port 81 having a large droplet size and a discharge port 82 having a small droplet size smaller than the discharge port 81. A plurality of each are arranged to form two rows of discharge ports. The two ejection port arrays configured in this manner are arranged in parallel so as to sandwich the ink supply port 3, and the ejection ports of each row are arranged at positions shifted from each other by a half of the ink flow path width. .
[0073]
Between each ink flow path 8 from the opening (ink inlet / outlet) on the ink supply port 3 side to the ink supply port 3, one filter 83 or 84 constituted by a column is disposed for each ink flow path. The filter 83 or 84 is formed in the same manner as the filter 10 shown in FIG. 1 and produces the same effect.
[0074]
The filters 83 and 84 branch the ink flow into a plurality of ink supply paths such as arrows 85 and 86 shown between the ink supply port 3 and the ink flow path 8.
[0075]
Here, as a characteristic feature, the cross-sectional area of the filter 83 corresponding to the discharge port 81 having a large droplet size (or the outer diameter of the column as the filter 83) is the filter corresponding to the discharge port 82 having a small droplet size. It is smaller than the cross-sectional area of 84 (or the outer diameter of the column that is the filter 84).
[0076]
At the location of the filter 83, the width of the space between the column of the filter 83 and the wall of the ink flow path 8 (the opening width of the ink supply path) is wider than the location of the filter 84. The width of the space between the column of the filter 84 and the wall of the ink flow path 8 (opening width of the ink supply path) is narrower than that of the filter 83.
[0077]
As a result, when ink with a large droplet size is ejected, the vibration transmitted to the ink channel with the small droplet size located between the ink supply port side and the ink channel with the large droplet size sandwiching the ink supply port Since the ink flow path has a large flow resistance due to the narrow opening width in the ink flow path with a small droplet size, the component is suppressed to a small size, so the effect of crosstalk on the ejection port array with a small droplet size It is possible to reduce the meniscus vibration to the ink discharge port. As a result, it is possible to stably eject ink droplets of different sizes from the ejection port arrays having different droplet sizes sharing the same ink supply port.
[0078]
(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. In the fourth embodiment, the meniscus at the small droplet size discharge port due to the crosstalk phenomenon is characterized in that the filter cross-sectional area is changed for each ink flow path connected to each of the ink discharge ports of different droplet sizes. Although it was suppression of vibration, meniscus vibration due to the crosstalk phenomenon may be suppressed depending on the number of filters installed, regardless of the size of the filter cross-sectional area as in this embodiment.
[0079]
FIG. 8 is a plan view showing the discharge port forming surface of the ink jet recording head in the fifth embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and different configurations from those in FIG. 1 and the fourth embodiment will be mainly described.
[0080]
In the ink jet recording head of this embodiment, as in the fourth embodiment, as shown in FIG. 8, two ink ejection port arrays are arranged substantially in parallel so as to sandwich the ink supply port, and each ink ejection column is arranged. The opening diameter of the discharge port is different. One ink discharge port array includes a plurality of discharge ports 91 each having a large droplet size, and the other ink discharge port array includes discharge ports 92 having a smaller droplet diameter than the discharge ports 91 and having a small droplet size. A plurality are arranged side by side.
[0081]
Between the ink supply port 3 side opening (ink inlet / outlet) of the ink flow path 8 and the ink supply port 3, a columnar filter 93 or 94 having the same cross-sectional area is disposed. The filter 93 or 94 is formed in the same manner as the filter 10 shown in FIG. 1 and produces the same effect.
[0082]
Here, as a characteristic feature, the filter 93 corresponding to the discharge port 91 having a large droplet size is a single column, whereas the filter 94 corresponding to the discharge port 92 having a small droplet size is two. It consists of pillars. In the present embodiment, as in the second embodiment, the number of columns to be a filter is set different for each ink flow path to the ejection port corresponding to each droplet size.
[0083]
As described above, by changing the number of filters installed on the upstream side of the ink flow path to the discharge ports having different droplet sizes, a plurality of arrows 65 and 66 shown between the ink supply port 3 and the ink flow path 8 are provided. Therefore, the flow resistance to the ink channel having a small droplet size can be adjusted to be larger than the flow resistance to the ink channel having a large droplet size. As a result, it is possible to suppress the influence of the pressure wave on the discharge port array having a small droplet size and the overshoot of the meniscus at the discharge port having a small droplet size when discharging ink having a large droplet size. Thus, it is possible to stably eject ink droplets of different sizes from the ejection port arrays sharing different ink supply ports and having different droplet sizes.
[0084]
This embodiment is different from the fourth embodiment in that it is advantageous when configuring a high-resolution recording chip and a high-frequency compatible recording chip that is driven to discharge at a high frequency. For example, when the ink discharge ports are arranged in a row so as to exhibit a resolution of 1200 dpi and an ink flow path leading to each discharge port is formed, a pitch of 1 inch (25.4 mm) / 1200 dpi = 21.1 microns is used. It is necessary to configure the flow path and the flow path wall. Therefore, the filter installation width per one ink flow path is reduced, and when it is desired to increase the ink supply speed from the upstream side of the ink flow path for high frequency, the ink supply port needs to be brought closer to the ink flow path. In addition, the distance from the end of the ink flow path wall to the opening edge of the ink supply port becomes narrow. Therefore, this embodiment is advantageous in that the cross-sectional area of each filter is fixed and the number of filters installed is different in such a narrow space.
[0085]
In addition, this invention is not limited only to the structure mentioned above, What kind of structure may be sufficient if it can achieve this invention. Therefore, according to the cross-sectional area of the filter, the number of filters installed is 1 to 3, 0 to 2 in the ratio of the number of filters corresponding to the discharge port having a large droplet size and the number of filters corresponding to the discharge port having a small droplet size. It is possible to make them different.
[0086]
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. Also in the present embodiment, an object is to suppress meniscus vibration at the discharge port having a small droplet size due to the crosstalk phenomenon by the filter configuration as in the fourth and fifth embodiments.
[0087]
FIG. 9 is a plan view showing an ejection port forming surface of an ink jet recording head according to the sixth embodiment of the present invention. In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and different configurations from those of FIG. 1 and the fourth and fifth embodiments will be mainly described.
[0088]
In the ink jet recording head of the present embodiment, as in the fourth embodiment, as shown in FIG. 9, two ink ejection port arrays are arranged substantially in parallel so as to sandwich the ink supply port, and each ink ejection column is arranged. The opening diameter of the discharge port is different. One ink discharge port array includes a plurality of discharge ports 101 having a large droplet size, and the other ink discharge port array includes discharge ports 102 having a smaller droplet diameter than the discharge ports 101 and having a small droplet size. A plurality are arranged side by side.
[0089]
Between the ink supply port 3 side opening (ink inlet / outlet) of the ink flow path 8 and the ink supply port 3, one columnar filter 103 or 104 having the same cross-sectional area is disposed for each ink flow path. The filter 103 or 104 is formed in the same manner as the filter 10 shown in FIG. 1 and produces the same effect.
[0090]
Here, as a characteristic feature, the filter 103 corresponding to the discharge port 101 having a large droplet size has an ink supply port at a distance X from the end 5B of the ink flow channel wall to the edge 3B ′ of the ink supply port. It is installed at a position close to the edge 3B ′. On the other hand, the filter 104 corresponding to the ejection port 102 having a small droplet size is located near the end 5B of the ink channel wall at the distance X from the end 5B of the ink channel wall to the edge 3B ′ of the ink supply port. Is installed. In other words, in the present embodiment, the installation position of the columnar filter 103 or 104 is within the range of the distance X from the end 5B of the ink flow path wall to the edge 3B ′ of the ink supply port on the upstream side of the ink flow path 8. Are different.
[0091]
For this reason, the width of the space between the column of the filter 103 and the wall of the ink flow path 8 (the opening width of the ink supply path) is wider at the location of the filter 103 than at the location of the filter 104. At the place, the width of the space between the column of the filter 104 and the wall of the ink flow path 8 (opening width of the ink supply path) is narrower than the place of the filter 103.
[0092]
In this way, by changing the filter installation position behind the ink flow paths having different droplet sizes, a plurality of ink supply paths such as arrows 105 and 106 shown between the ink supply port 3 and the ink flow path 8 can be obtained. The flow resistance to the ink channel having a small droplet size can be adjusted to be larger than the flow resistance to the ink channel having a large droplet size. As a result, it is possible to suppress the influence of the pressure wave on the discharge port array having a small droplet size and the overshoot of the meniscus at the discharge port having a small droplet size when discharging ink having a large droplet size. Thus, it is possible to stably eject ink droplets of different sizes from the ejection port arrays sharing different ink supply ports and having different droplet sizes.
[0093]
This embodiment is different from the fourth and fifth embodiments in that it is advantageous when configuring a high-resolution recording chip. For example, when the ink discharge ports are arranged in a row so as to exhibit a resolution of 1200 dpi and an ink flow path leading to each discharge port is formed, a pitch of 1 inch (25.4 mm) / 1200 dpi = 21.1 microns is used. It is necessary to configure the flow path and the flow path wall. For this reason, the filter installable width per one ink flow path is reduced.
[0094]
Therefore, this embodiment is advantageous in that the cross-sectional area of each filter is fixed and the number of filters installed is different in such a narrow space.
[0095]
【The invention's effect】
  As described above, according to the present invention, in an ink jet recording head in which the sizes of droplets ejected from a plurality of ejection ports are mixed at least two sizes, a flow that communicates with one liquid supply port and each ejection port. A columnar filter structure is arranged between each of the paths,Corresponding to the first filter structure corresponding to the flow path with the first discharge port for discharging a predetermined droplet size and the flow path with the second discharge port for discharging a larger droplet than the first discharge port The flow resistance between the flow path including the first discharge port and the supply port is reduced between the flow path including the second discharge port and the supply port. By making it larger than the flow resistance, it becomes possible to eject droplets at the same ejection frequency from the first and second ejection ports having different ejection droplet sizes.
[0096]
  Also,A first discharge port array including a plurality of first discharge ports, and a second discharge port array including a plurality of second discharge ports, and the first and second discharge port arrays include supply ports. In the case of a head configuration in which two rows are arranged so as to be sandwiched, droplets of different sizes can be stably ejected from ejection port rows having different droplet sizes sharing the same supply port.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a portion near a discharge port of a recording head that discharges one color of ink in an ink jet recording head that preferably implements the present invention, and FIG. (B) shows the AA 'line sectional view of (a).
FIG. 2 is a diagram illustrating a configuration of a main part of an example of an ink jet recording apparatus equipped with the ink jet recording head of the present invention.
3 is a perspective view from the discharge port forming surface side of the recording head shown in FIG. 2. FIG.
FIG. 4 is a plan view showing a discharge port forming surface of the ink jet recording head in the first embodiment of the invention.
FIG. 5 is a plan view showing a discharge port forming surface of an ink jet recording head according to a second embodiment of the present invention.
FIG. 6 is a plan view showing a discharge port forming surface of an ink jet recording head according to a third embodiment of the present invention.
FIG. 7 is a plan view showing a discharge port forming surface of an ink jet recording head according to a fourth embodiment of the present invention.
FIG. 8 is a plan view showing a discharge port forming surface of an ink jet recording head according to a fifth embodiment of the present invention.
FIG. 9 is a plan view showing a discharge port forming surface of an ink jet recording head according to a sixth embodiment of the present invention.
[Explanation of symbols]
1 electrothermal transducer
2 Ink ejection port
3 Ink supply port
3B 'edge of ink supply port
4 Substrate having electrothermal conversion element
5 Wall of ink flow path using mold resin
5B End of ink channel wall
6 Mold resin
8 Ink flow path
10 Columnar filter
11 Orifice plate
12 Ink liquid chamber (also called common liquid chamber)
21 Recording head
22 Ink tank
23 Drive motor
24 Drive belt
25 Recording enclosure
26 Paper feed and transport mechanism
27 Suction recovery cap
28 Wiper blade
34 Recording chip
51, 61, 71, 81, 91, 101 Discharge port with large droplet size
52, 62, 72, 82, 92, 102 Discharge port with small droplet size
53, 54, 63, 64, 73, 74, 83, 84, 93, 94, 103, 104 Columnar filter
55, 56, 65, 66, 75, 76, 85, 86, 95, 96, 105, 106 Arrows representing ink supply paths

Claims (6)

A plurality of discharge ports for discharging liquid droplets, a liquid chamber for storing liquid to be supplied to respective discharge ports, a supply port for supplying the liquid to the liquid chamber, the liquid chamber and the respective discharge ports A plurality of flow paths communicating with each other, a flow path wall forming the flow path , a filter structure formed by a column between each flow path and the supply port, and discharging to the liquid in the flow path in the ink jet recording head and a discharge energy generating element for applying energy,
The plurality of discharge ports include a first discharge port that discharges a droplet having a predetermined size, and a second discharge port that discharges a liquid suitable for a liquid larger than the droplet discharged from the first discharge port. With
The filter structure includes a first filter structure provided corresponding to the flow path including the first discharge port, and a second filter provided corresponding to the flow path including the second discharge port. A structure,
The path that communicates between the supply port and each flow path is divided into a plurality by the filter structure and the flow path wall,
Due to the first and second filter structures, the flow resistance between the flow path including the first discharge port and the supply port is between the flow path including the second discharge port and the supply port. An ink jet recording head characterized by having a larger flow resistance . A first discharge port array including a plurality of the first discharge ports and a second discharge port array including a plurality of the second discharge ports, and the first and second discharge port arrays, 2. The ink jet recording head according to claim 1, wherein two rows are arranged so as to sandwich the supply port. 3. The ink jet recording head according to claim 1, wherein a cross-sectional area of a column constituting the first filter structure is larger than a cross-sectional area of a column constituting the second filter structure. 3. The ink jet recording head according to claim 1, wherein the number of columns constituting the first filter structure is greater than the number of columns constituting the second filter structure. 3. The ink jet recording head according to claim 1, wherein the position of the pillar constituting the first filter structure is closer to the ejection port side than the position of the pillar constituting the second filter structure.   An ink jet recording apparatus comprising the ink jet recording head according to claim 1, wherein recording is performed by ejecting liquid droplets onto a recording medium from an ejection port of the ink jet recording head.

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