Liquid discharge head, liquid discharge apparatus, and manufacturing method

A liquid discharge head includes a recording element substrate having first to fourth discharge port groups, each of which includes a plurality of discharge ports for discharging liquid, first flow path connecting a first liquid tank to the first discharge port group, a second flow path connecting a second liquid tank to the second discharge port group, and a third flow path connecting a third liquid tank to the third discharge port group and the fourth discharge port group, wherein a flow resistance in the first flow path is smaller than a flow resistance in the second flow path and larger than a flow resistance in the third flow path, and wherein a ratio of the flow resistance in the second flow path to the flow resistance in the third flow path is 4 or less.

BACKGROUND OF THE INVENTION

Field of the Invention

The disclosure relates to a liquid discharge head, a liquid discharge apparatus, and a manufacturing method.

Description of the Related Art

A liquid discharge apparatus for, for example, performing recording processing by discharging a liquid from a discharge port has been widely used. This type of liquid discharge apparatus includes a liquid discharge head. The liquid discharge head includes a plurality of discharge ports formed in a recording element substrate, a pressure chamber communicating with each of the discharge ports, and a flow path for supplying the liquid to the pressure chamber. The liquid is supplied from a liquid tank to the liquid discharge head. In such a liquid discharge head, an air bubble is sometimes formed in the liquid in the flow path and the pressure chamber. An air bubble left as it is may disturb the supply the liquid and cause a discharging failure. For this reason, the main body of the liquid discharge apparatus includes suction recovery means that performs a suction recovery process for removing a formed air bubble by suction.

Some liquid discharge heads have a plurality of discharge port arrays, which is provided on a recording element substrate, for discharging different types of liquid. In general, this type of liquid discharge head performs the suction recovery process by simultaneously covering the discharge port arrays formed on a single member using a cap and depressurizing the inside of the cap by a suction pump.

A desirable negative pressure in suction for depressurization using the suction pump is a degree sufficient for removing the air bubble by suction and not drawing a bubble from the liquid tank. Such a degree of negative pressure of suction varies depending on flow resistance in a path from the liquid tank to the discharge port. Flow resistance in a path from the liquid tank to the discharge port may greatly vary among different types of liquid, depending on a structure of the liquid discharge apparatus. For example, Japanese Patent Application Laid-Open No. 2010-76394 discusses a liquid discharge apparatus having differences in sizes of discharge ports for discharging a liquid and differences in the number of arrays of discharge ports connected to one liquid tank, depending on types of liquid. When there are variations in the number of discharge port arrays connected to one liquid tank, the number of discharge ports connected to one liquid tank varies. Consequently, the sum of the opening areas of the discharge ports greatly varies among liquid tanks. The flow resistance therefore greatly varies among flow paths from the liquid tank to discharge ports.

In a case where the flow resistance greatly varies among flow paths from the liquid tank to the discharge ports, it is difficult to set a suction amount well-balanced among the flow paths using such a method that a suction is simultaneously performed for a plurality of flow paths as described above. It is therefore difficult for the above-described liquid discharge apparatus to adopt a recovery method using simultaneous suction.

To address such an issue, Japanese Patent No. 5153427 discusses a liquid discharge head that adjusts a difference between flow resistances occurring in flow paths from liquid tanks to discharge ports using filter provided at an opening portion of each liquid inlet.

However, in the liquid discharge head discussed in Japanese Patent No. 5153427, the resistance occurring in the filter is small relative to the flow resistance occurring in the flow path. The liquid discharge head therefore has limitation in an adjustable flow resistance range in reality. Moreover, no consideration is given to the degree of flow-resistance difference that allows adoption of the recovery method using simultaneous suction. Accordingly, the liquid discharge head often still has difficulty in adopting the method of simultaneous suction recovery.

SUMMARY OF THE INVENTION

The disclosure is directed to a liquid discharge head capable of subjecting a plurality of liquids to a simultaneous suction for recovery, by reducing a flow-resistance difference between flow paths.

According to an aspect of the present disclosure, a liquid discharge head includes recording element substrate having a first discharge port group, a second discharge port group, a third discharge port group, and a fourth discharge port group, each of which includes plurality of discharge ports for discharging liquid, a first flow path connecting a first liquid tank to the first discharge port group, a second flow path connecting a second liquid tank to the second discharge port group, and a third flow path connecting a third liquid tank to the third discharge port group and the fourth discharge port group, wherein a flow resistance in the first flow path is smaller than a flow resistance in the second flow path and larger than a flow resistance in the third flow path, and wherein a ratio of the flow resistance in the second flow path to the flow resistance in the third flow path is 4 or less.

According to another aspect of the present disclosure, a liquid discharge apparatus includes the above-described liquid discharge head.

According to yet another aspect of the present disclosure, a method for manufacturing a liquid discharge head including a recording element substrate having a first discharge port group, a second discharge port group, a third discharge port group, and a fourth discharge port group, each of which includes a plurality of discharge ports for discharging liquid, first flow path connecting a first liquid tank to the first discharge port group, second flow path connecting a second liquid tank to the second discharge port group, and a third flow path connecting a third liquid tank to the third discharge port group and the fourth discharge port group, the method includes determining size and arrangement of the plurality of discharge ports included in each of the first to the fourth discharge port groups, and determining a length of each of the first to the third flow paths to set a ratio of a largest flow resistance to a smallest flow resistance among flow resistances in the first to the third flow paths to 4 or less.

DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the disclosure will be described below with reference to the attached drawings. In the present specification and drawings, constituent elements having the same function may be provided with the same reference numerals and redundant description thereof will be avoided.

FIG. 1is a perspective view of a schematic configuration of a liquid discharge apparatus100. The liquid discharge apparatus100is an apparatus that forms an image on a record medium by discharging a liquid, such as ink. The liquid discharge apparatus100is, for example, an inkjet recording apparatus. The liquid discharge apparatus100has a chassis101including a lower case101aand an upper case101b. The lower case101aforms substantially a lower half of the liquid discharge apparatus100. The upper case101bforms substantially an upper half of the liquid discharge apparatus100. The chassis101is housed in an exterior member (not illustrated). The chassis101is configured of one or more sheet metal members having predetermined rigidity, and forms a frame of the liquid discharge apparatus100. Fitting the upper case101band the lower case101aforms a hollow body structure having a space therein. The hollow body structure has an opening formed in each of a top surface portion and a front surface portion thereof.

The liquid discharge apparatus100has, as a mechanism for performing recording operation, a feeding unit102and a conveyance unit103. The feeding unit102feeds a record medium into the main body of the liquid discharge apparatus100. The conveyance unit103guides the record medium sent out from the feeding unit102, to a desired recording position. The conveyance unit103further guides the record medium from the recording position to an eject unit106. The liquid discharge apparatus100further has, as the mechanism for performing the recording operation, a recording unit104and a recovery unit105. The recording unit104performs recording by discharging the liquid to the record medium conveyed to the recording position. The recovery unit105performs a recovery process for, for example, the recording unit104.

The recording unit104has a carriage112, a liquid discharge head113, and a plurality of liquid tanks114. The carriage112is movably supported by a carriage axis111. The liquid discharge head113is detachably attached to the carriage112. The liquid tanks114each retain the liquid to be supplied to the liquid discharge head113. The liquid retained by the liquid tanks114is, for example, ink to be used for recording. The liquid discharge head113illustrated inFIG. 1is of a so-called cartridge type, which is detachably attachable to the carriage112. The liquid discharge head113may be of a type other than the cartridge type. For example, the liquid discharge head113may be of a head-tank integrated cartridge type in which the liquid tanks114and the liquid discharge head113are integrated into one unit to be detachably attachable to the carriage112. Alternatively, the liquid discharge head113may be integral with the carriage112, and the liquid tanks114may be detachably attachable to the liquid discharge head113. The liquid tanks114retain different types of liquids, e.g., of different colors. Each of the liquid tanks114retains a different color of inks, for example, black, gray, cyan, magenta, and yellow inks, and is individually detachably attachable to the liquid discharge head113. Alternatively, instead of having an independent-type configuration illustrated inFIG. 1, the liquid tanks114may have such a configuration that a plurality of liquid retention chambers is accommodated in a single housing and each of the liquid retention chambers retains a different liquid.

FIGS. 2 and 3are perspective views of the liquid discharge head113. As illustrated inFIG. 2, one side of the liquid discharge head113is partitioned to a plurality of spaces each for containing a different one of the liquid tanks114. A filter7is provided in each of the spaces. The filter7includes filters7afor chromatic color ink and a filter7bfor black ink. The filter7is pressed against a liquid supply port (not illustrated) of the liquid tanks114to catch dust and bubbles in the liquid supplied from the liquid tanks114. The dust and bubbles are thus prevented from entering the liquid discharge head113.

As illustrated inFIG. 3, the liquid discharge head113has a recording element substrate1for chromatic color ink, a recording element substrate2for black ink, a support substrate3, a flow path forming member4, and a chip tank5. The recording element substrate1for chromatic color ink and the recording element substrate2for black ink are substrates, such as silicon substrates, on which energy generating elements and electrical wiring are formed. The energy generating elements generate energy for discharging the liquid. The electrical wiring supplies power to each of the energy generating elements. Further, the recording element substrates1and2have discharge ports, each formed at a position corresponding to a different one of the energy generating elements, for discharging the liquid. On the back of the side in which the discharge ports are formed, supply ports (not illustrated) are formed. Each of the supply ports communicates with different one of the discharge ports, and serves as an opening for receiving supply of the liquid. The recording element substrates1and2described above are fixed to adhere to the support substrate3. Each of the supply ports formed in the recording element substrates1and2forms a space together with the support substrate3. The space is for holding the liquid as a liquid chamber. The liquid discharge head113has flow paths connecting the supply ports formed in the recording element substrates1and2to the filter7.

FIGS. 4 and 5illustrate an example of a flow path configuration for connecting the supply ports formed in the recording element substrate1for chromatic color ink to the filters7aillustrated inFIG. 2.FIG. 5is a plan view corresponding toFIG. 4. A supply flow path6aillustrated inFIGS. 4 and 5is connected to a different one of the filters7aillustrated inFIG. 2. The supply flow path6aruns in a thickness direction of the recording element substrate1. A horizontal flow path8connects the supply flow path6ato a different one of liquid chambers9ato9h. The horizontal flow path8runs almost in parallel with an in-plane direction of the recording element substrate1. The horizontal flow path8is formed by the flow path forming member4illustrated inFIG. 3. The liquid chambers9aand9hare branched from one flow path and are supplied with the same liquid. The liquid chambers9band9g, as well as the liquid chambers9dand9f, are configured similarly to the liquid chambers9aand9h. Each of the liquid chambers9ato9hcorresponds to a discharge port array. The liquid is supplied from each of the liquid chambers9ato9hto the discharge ports. Accordingly, the supply flow path6aand the horizontal flow path8form a part of a flow path that connects the liquid tank114to the discharge port array.

FIG. 6illustrates a mechanism for suctioning an air bubble generated at the recording element substrate1for chromatic color ink. A cap11dedicated for chromatic color ink is provided to cover the recording element substrate1for chromatic color ink which is fixed to the support substrate3. A tube13for ink suction is connected to the cap11dedicated for chromatic color ink, and a suction pump P is connected to the tube13. The suction pump P depressurizes the inside of the cap11dedicated for chromatic color ink by applying negative pressure. The liquids are thus suctioned simultaneously from the discharge ports provided in the recording element substrate1.

The desirable negative pressure in suction in this process is a degree sufficient for removing the air bubble by suction and not drawing a bubble from the liquid tank. Such a degree of negative pressure in suction varies depending on the flow resistances in the entire paths from liquid tanks to discharge ports. It is therefore desirable to set differences of flow resistances within a predetermined range. Specifically, a desirable flow-resistance ratio among the flow paths connected to the discharge ports which are subjected to simultaneous suction is 4 or less. In other words, the desirable ratio of the highest flow resistance to the lowest flow resistance is 4 or less. If flow paths having a large flow-resistance difference are simultaneously subjected to a suction recovery process, the amount of the liquid suctioned from a flow path having a small flow resistance is larger than the amount of the liquid suctioned from a flow path having a large flow resistance. This increases the amount of waste ink accompanying the suction recovery process and raises running cost. Further, if the negative pressure of suction is applied to the extent that an air bubble can be sufficiently suctioned from the flow path having the large flow resistance, the negative pressure of suction is too large for the flow path having the small flow resistance. Consequently, the rate of supply flow from the liquid tank increases, and a bubble may be drawn together with the liquid into the flow path. In contrast, if the negative pressure of suction is applied to the extent that an air bubble can be sufficiently suctioned from the flow path having the small flow resistance, the negative pressure of suction is too small for the flow path having the large flow resistance. Consequently, the air bubble may not be sufficiently suctioned from the flow path having the large flow resistance.

Flow resistance in a flow path varies depending on, for example, the sum of the opening areas of the discharge ports to which the flow path is connected, the length of the flow path, and the thickness of the flow path. The sum of the opening areas of the discharge ports varies depending on the size and the number of the discharge ports. When a configuration including the size and arrangement of the discharge ports is determined according to the function of the liquid discharge apparatus, the length of each of the flow paths can be determined so that the flow-resistance ratio is 4 or less, by adjusting the placement of the liquid tank to be connected to each of the flow paths, and the route of each of the flow paths, according to the configuration of the discharge ports.

FIG. 7is a diagram illustrating an example of a configuration of discharge ports of a recording element substrate1according to a first exemplary embodiment of the disclosure.

The recording element substrate1includes discharge ports classified into three types, that are large discharge ports50, medium discharge ports51, and small discharge ports52, which have difference in liquid discharge amounts. The medium discharge ports51are smaller than the large discharge ports50, and the small discharge ports52are smaller than the medium discharge ports51. The discharge ports of these three types are divided into discharge port groups each including plurality of discharge ports receiving the liquid from a single liquid chamber9. Specifically, the recording element substrate1has a cyan discharge port group43a, a magenta discharge port group42a, and a gray discharge port group41. The cyan discharge port group43ais supplied with ink of cyan color from a liquid chamber9a. The magenta discharge port group42ais supplied with ink of magenta color from a liquid chamber9b. The gray discharge port group41is supplied with ink of gray color from a liquid chamber9c. The recording element substrate1further has a black discharge port group44aand a yellow discharge port group40. The black discharge port group44ais supplied with ink of black color from a liquid chamber9d. The yellow discharge port group40is supplied with ink yellow color from a liquid chamber9e. Furthermore, the recording element substrate1has a black discharge port group44b, a magenta discharge port group42b, and a cyan discharge port group43b. The black discharge port group44bis supplied with ink of black color from a liquid chamber9f. The magenta discharge port group42bis supplied with ink of magenta color from a liquid chamber9g. The cyan discharge port group43bis supplied with ink of cyan color from a liquid chamber9h.

The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50, one discharge port array of the medium discharge ports51, and one discharge port array of the small discharge ports52. The gray discharge port group41includes two discharge port arrays of the medium discharge ports51, and two discharge port arrays of the small discharge ports52. The black discharge port groups44aand44beach include one discharge port array of the large discharge ports50and one discharge port array of the medium discharge ports51. The yellow discharge port group includes two discharge port arrays of the large discharge ports50.

The liquid chambers9aand9hare branched from one flow path and configured be supplied with the same liquid, as illustrated inFIG. 4. The liquid chambers9band9g, as well as the liquid chambers9dand9f, are similarly configured. Therefore, the ink of the same color is supplied from the one liquid tank to each of the cyan discharge port groups43aand43b. This holds true for the magenta discharge port groups42aand42b, as well as the black discharge port groups44aand44b.

As illustrated inFIG. 7, the discharge port groups each include the discharge ports varying in size and number. The sum of the opening areas of the discharge ports varies among the discharge port groups. In the example illustrated inFIG. 7, the sum of the opening areas of the discharge ports is the largest in the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42b, and the smallest in the gray discharge port group41. Therefore, in a case where the flow paths connected to the discharge port groups have the same thickness and length, the flow resistance in each of the flow paths connected to the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42bis the smallest. Further, the flow resistance in the flow path connected to the gray discharge port group41is the largest. In this example, the ratio of the flow resistance in the flow path connected to the gray discharge port group41to the flow resistance in the flow path connected to the cyan discharge port groups43aand43bor the magenta discharge port groups42aand42bis approximately 3.3, which falls in the range of 4 or less. Even when the flow resistances vary due to a manufacturing process, the flow-resistance ratio is approximately 3.8. In a case where this flow-resistance ratio falls in the range of 4 or less, the discharge port groups can be covered with a single cap and simultaneously subjected to a suction recovery process.

In this example, to achieve the flow-resistance ratio of 4 or less, the length of the flow path connected to the gray discharge port group41having the largest flow resistance is set shorter than those of the flow paths for supplying the ink of other colors. The resistance occurring in the flow path connected to the gray discharge port group41is thus made small. The length of the flow path is adjusted, by adjusting the placement of the liquid tank to be connected to each of the flow paths, and the route of each of the flow paths, so that the flow-resistance ratio is 4 of less. The flow resistance in the flow path described above refers to the flow resistance in the entire route of each of the flow paths, i.e., the flow resistance in the entire route of each of the flow paths that connect the liquid tanks to the discharge port groups.

The yellow discharge port group40is referred to as a first discharge port group. The gray discharge port group41is referred to as a second discharge port group of discharge ports that are smaller than large discharge ports of the first discharge port group. In this case, the cyan discharge port group43aor the magenta discharge port group42ais referred to as a third discharge port group or a fifth discharge port group of the large discharge ports and discharge ports that are smaller than the large discharge ports. In a case where the cyan discharge port group43ais referred to as the third discharge port group, the cyan discharge port group43bis referred to as a fourth discharge port group. In a case where the cyan discharge port group43ais referred to as the fifth discharge port group, the cyan discharge port group43bis referred to as a sixth discharge port group. Further, the black discharge port group44ais referred to as a seventh discharge port group, and the black discharge port group44bis referred to as an eighth discharge port group.

FIG. 8is a diagram illustrating an example of a configuration of discharge ports of a recording element substrate1for chromatic color ink mounted on a liquid discharge head113according to a second exemplary embodiment of the disclosure.

To reduce the size of the liquid discharge head113according to the first exemplary embodiment, the recording element substrate1in the present exemplary embodiment is not provided with the black discharge port group44. In the present exemplary embodiment, the recording element substrate1has six liquid chambers, and six discharge port groups each formed corresponding to the six liquid chambers. In addition, in the present exemplary embodiment, the small discharge ports52is not provided in the recording element substrate1, and the recording element substrate1has two types of discharge ports, which are the large discharge ports50and the medium discharge ports51. The cyan discharge port groups43aand43bare symmetrically provided on both sides of the yellow discharge port group40. The magenta discharge port groups42aand42bare similarly provided. The gray discharge port group41is provided between the yellow discharge port group40and the magenta discharge port group42a. This can suppress interference of airflow between the yellow discharge port group40and the magenta discharge port group42a.

The yellow discharge port group40includes two discharge port arrays including only the large discharge ports50. The gray discharge port group41includes discharge ports smaller than the large discharge ports50. In the example illustrated inFIG. 8, the gray discharge port group41includes two discharge port arrays including only the medium discharge ports51. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include the large discharge ports50and discharge ports smaller than the large discharge ports50. In the example illustrated inFIG. 8, the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50, and one discharge port array of the medium discharge ports51.

In the configuration illustrated inFIG. 8, the sum of the opening areas of the discharge ports is the largest in the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42b, and the smallest in the gray discharge port group41, as in the first exemplary embodiment. Therefore, in a case where flow paths connected to the discharge port groups have the same thickness and length, the flow resistance in each of the flow paths connected to the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42bis the smallest. Further, the flow resistance in the flow path connected to the gray discharge port group41is the largest. The ratio of the flow resistance in the flow path connected to the gray discharge port group41to the flow resistance in the flow path connected to the cyan discharge port groups43aand43bor the magenta discharge port groups42aand42bis thus set to 4 or less. Accordingly, a plurality of discharge port groups can be covered with a single cap and simultaneously subjected to a suction recovery process.

Modification Examples

FIGS. 9 to 13illustrate modification examples of the second exemplary embodiment of the disclosure.

FIG. 9illustrates a first modification example of the second exemplary embodiment. In the second exemplary embodiment illustrated inFIG. 8, the recording element substrate1has the two types of discharge ports that are the large discharge ports50and the medium discharge ports51. In contrast, in the first modification example, the recording element substrate1has the small discharge ports52in place of the medium discharge ports51. Specifically, in the first modification example, the gray discharge port group41includes discharge ports smaller than the large discharge ports50. To be more specific, the gray discharge port group41includes two discharge port arrays of the small discharge ports52. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50and one discharge port array of the small discharge ports52. The yellow discharge port group40includes two discharge port arrays of the large discharge ports50, as in the second exemplary embodiment.

FIG. 10illustrates a second modification example of the second exemplary embodiment. In the second modification example, the small discharge ports52are provided in place of some of the medium discharge ports51included in the configuration illustrated inFIG. 8. Specifically, in the second modification example, the yellow discharge port group40includes two discharge port arrays of the large discharge ports50, as in the second exemplary embodiment. The gray discharge port group41includes one discharge port array of the medium discharge ports51and one discharge port array of the small discharge ports52. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50and one discharge port array of the medium discharge ports51.

FIG. 11illustrates a third modification example of the second exemplary embodiment. In the third modification example, the yellow discharge port group40includes two discharge port arrays of the large discharge ports50, as in the second exemplary embodiment. The gray discharge port group41includes one discharge port array of the medium discharge ports51and one discharge port array of the small discharge ports52. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50and one discharge port array of the small discharge ports52.

FIG. 12illustrates a fourth modification example of the second exemplary embodiment. In the fourth modification example, the yellow discharge port group40includes two discharge port arrays of the large discharge ports50, as in the second exemplary embodiment. The gray discharge port group41includes two discharge port arrays of the small discharge ports52. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50and one discharge port array of the medium discharge ports51.

FIG. 13illustrates a fifth modification example of the second exemplary embodiment. In the fifth modification example, the yellow discharge port group40includes two discharge port arrays of the large discharge ports50, as in the second exemplary embodiment. The gray discharge port group41includes two discharge port arrays of the medium discharge ports51. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50and one discharge port array of the small discharge ports52.

In the modification examples of the second exemplary embodiment of the disclosure illustrated inFIGS. 9 to 13, likewise, the sum of the opening areas of the discharge ports is the largest in the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42b, and the smallest in the gray discharge port group41. Therefore, in a case where flow paths connected to the discharge port groups have the same thickness and length, the flow resistance in each of the flow paths connected to the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42bis the smallest. Further, the flow resistance in the flow path connected to the gray discharge port group41is the largest. The ratio of the flow resistance in the flow path connected to the gray discharge port group41to the flow resistance in the flow path connected to the cyan discharge port groups43aand43bor the magenta discharge port groups42aand42bis thus set to 4 or less. Accordingly, a plurality of discharge port groups can be covered with a single cap and simultaneously subjected to the suction recovery process.

FIG. 14illustrates a third exemplary embodiment of the disclosure. The third exemplary embodiment provides a gradation property improved from that in the liquid discharge head113according to the second exemplary embodiment. To this end, a gray discharge port group41has four discharge port arrays of two types of discharge ports, and cyan discharge port groups43aand43bas well as magenta discharge port groups42aand42beach include three discharge port arrays of three types of discharge ports. Specifically, the gray discharge port group41includes two discharge port arrays of the medium discharge ports51and two discharge port arrays of the small discharge ports52. The cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42beach include one discharge port array of the large discharge ports50, one discharge port array of the medium discharge ports51, and one discharge port array of the small discharge ports52. A yellow discharge port group40includes two discharge port arrays of the large discharge ports as in the first and the second exemplary embodiments.

In the configuration illustrated inFIG. 14, likewise, the sum of the opening areas of the discharge ports is the largest in the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42b, and the smallest in the gray discharge port group41. Therefore, in a case where flow paths connected to the discharge port groups have the same thickness and length, the flow resistance in each of the flow paths connected to the cyan discharge port groups43aand43bas well as the magenta discharge port groups42aand42bis the smallest. Further, the flow resistance in the flow path connected to the gray discharge port group41is the largest. The ratio of the flow resistance in the flow path connected to the gray discharge port group41to the flow resistance in the flow path connected to the cyan discharge port groups43aand43bor the magenta discharge port groups42aand42bis thus set to 4 or less. Accordingly, a plurality of discharge port groups can be covered with a single cap and simultaneously subjected to a suction recovery process.

The present disclosure is described above with reference to the exemplary embodiments, but is not limited to the exemplary embodiments. Various modifications that a person skilled in the art can understand within the scope of technical ideas of the present disclosure can be made to configurations and details of the present disclosure.

In the exemplary embodiments described above, the liquid tanks, the flow paths connecting the discharge ports to the liquid tanks, the arrangement and the number of the discharge port groups are described using examples, but the disclosure is not limited to these examples. For example, the placement of the liquid tank retaining the ink of cyan color can be interchanged with the placement of the liquid tank retaining the ink of magenta color.

In the exemplary embodiments described above, the configuration of the liquid discharge head and the liquid discharge apparatus is mainly described. However, it is possible to provide a method for designing a liquid discharge head and a method for manufacturing a liquid discharge apparatus for implementing the above-described configuration.

According to the disclosure, a plurality of liquids can be simultaneously subjected to suction recovery, by reducing a flow-resistance difference between flow paths.

This application claims the benefit of Japanese Patent Application No. 2016-149980, filed Jul. 29, 2016, which is hereby incorporated by reference herein in its entirety.