Flow path member, liquid ejecting head and liquid ejecting apparatus

A pressure chamber in which an opening of a groove-shaped flow paths configuring a portion of a liquid flow path is formed by sealing with a film, a valve body which opens and closes a communication path communicating with the pressure chamber, and a pressure receiving member which is pressed by the film displaced to the pressure chamber side by negative pressure of the pressure chamber and is able to press the valve body in a direction where the valve body is valve opening state are included, and the valve body includes a flange section, a shaft section connected to the flange section and a seal member, and the seal member is formed in a shape of an annulus surrounding the shaft section.

BACKGROUND

1. Technical Field

The present invention relates to a flow path member, a liquid ejecting head and a liquid ejecting apparatus.

2. Related Art

As a liquid ejecting apparatus ejecting liquid from a nozzle of a liquid ejecting head to a target, for example, an ink jet type recording apparatus (hereinafter, simply referred to as “a recording apparatus”) ejecting ink droplets from a nozzle of an ink jet type recording head (hereinafter, simply referred to as “a recording head”) is well known.

The recording head is configured of a head body ejecting a ink and a flow path member to which the ink is supplied from an ink reservoir unit such as an ink cartridge and through which the ink is supplied to the head body. The flow path member has, for example, a pressure adjustment unit adjusting the pressure of the ink to be supplied to the head body to be in a predetermined range.

The pressure adjustment unit is configured in such a manner that for example, a pressure chamber is formed by sealing an opening of a groove-shaped flow path with a film and a communication path communicating with the pressure chamber is opened and closed by a valve body due to pressure variation in the pressure chamber (see JP-A-2008-230196).

The valve body has a seal member coming in contact with an opening edge of the communication path. The communication path may be reliably closed using the valve body with the seal member.

However, whenever the valve body opens and closes the communication path due to the pressure variation in the pressure chamber, the ink is gradually accumulated on the opening edge of the communication path. When the accumulation of the ink progresses, the opening-closing operation of the valve body is unstable. For example, the opening degree of the valve body is varies according to an accumulation amount of the ink, even though the same degree of pressure variation occurs in the pressure chamber. Thus, the supply of the ink to the head body is unstable, ejection characteristics of the ink vary and then printing quality is degraded. In addition, when the accumulation of the ink progresses further, sealing by the seal member may be incomplete, even in a state where the valve body closes the communication path. In this case, there is concern that the ink may be ejected from the nozzle of the head body at an unintended timing.

In addition, the problem described above is not limited to the flow path member for the ink jet type recording head and similarly exists in a flow path member which supplies liquid other than the ink to another member. In addition, the problem described above is not limited to the ink jet type recording head and similarly exists in a liquid ejecting head and a liquid ejecting apparatus ejecting the liquid other than the ink.

SUMMARY

An advantage of some aspects of the invention is to provide a flow path member where an opening-closing operation of a valve body is stabilized by suppressing accumulation of the liquid on an opening edge of a communication path communicating with a pressure chamber, and supply of the liquid can be stably performed, a liquid ejecting head and a liquid ejecting apparatus in which ejection characteristics of a liquid are made stable by using the flow path member.

According to an aspect of the invention, there is provided a flow path member including: a liquid flow path through which a liquid flows; a groove-shaped flow path configuring a portion of the liquid flow path and a communication path communicating with the groove-shaped flow path; a flexible member which forms a pressure chamber in the groove-shaped flow path by sealing an opening of the groove-shaped flow path and is flexibly deformed by pressure variation inside the pressure chamber; a valve body which has a shaft section inserted through the communication path and a valve main body provided on the shaft section, is able to enter a valve closing state in which the valve main body closes the communication path and a valve opening state in which the valve main body is separated from the communication path, and is biased to be in the valve closing state; and a pressure receiving member which is displaced by receiving a pressing force from the flexible member due to displacement of the flexible member to the pressure chamber side and then is able to press the shaft section in a direction where the valve body enters the valve opening state, wherein the valve body is able to rotate around the shaft center, the valve main body is provided with, a seal member which comes in contact with an opening edge of the communication path, and the seal member is formed in a shape of an annulus of which a distance from the shaft section is not constant.

In the aspect, an accumulation of the liquid formed on the opening edge can be spread and thinned so that it is possible to almost completely eliminate the influence of the accumulated liquid with respect to an opening-closing operation of the valve body in the communication path.

Accordingly, the flow path member is configured in such a manner that the operation of the valve body can be stable and the liquid can be stably supplied without the occurrence of variation in the opening-closing operation of the valve body.

According to another aspect of the invention, there is provided a flow path member comprising: a liquid flow path through which a liquid flows; a groove-shaped flow path configuring a portion of the liquid flow path and a communication path communicating with the groove-shaped flow path; a flexible member which forms a pressure chamber in the groove-shaped flow path by sealing an opening of the groove-shaped flow path and is flexibly deformed by pressure variation inside the pressure chamber; a valve body which has a shaft section inserted through the communication path and a valve main body provided on the shaft section, is able to enter a valve closing state in which the valve main body closes the communication path and a valve opening state in which the valve main body is separated from the communication path, and is biased to be in the valve closing state; and a pressure receiving member which is displaced by receiving a pressing force from the flexible member due to displacement of the flexible member to the pressure chamber side and then is able to press the shaft section in a direction where the valve body enters the valve opening state, wherein the valve main body is provided with a seal member which comes in contact with the opening edge of the communication path, and the seal member includes a water-repellent resin to be dissociated when the opening edge is sealed in the valve opening state of the valve body.

In the aspect, the seal member including the water-repellent resin is formed and the water-repellent resin is attached to the opening edge facing the seal member according to an opening-closing operation of the valve body. Thus, liquid attaching to the opening edge is suppressed. Accordingly, the flow path member is configured in such a manner that the operation of the valve body can be stable and the liquid can be stably supplied without the occurrence of variation in the opening-closing operation of the valve body.

It is preferable that the seal member be formed so as to pass through the shaft section in a plane perpendicular to the shaft section and to be line symmetrical with respect to two shafts perpendicular to each other. Accordingly, the bias force biasing the valve body is evenly applied to the entire seal member and the sealing with the opening edge is improved.

In addition, it is preferable that the water-repellent treatment be performed on the surface of the opening edge of the communication path. Accordingly, the liquid fixing to the opening edge can be further reliably prevented.

It is preferable that the seal member be formed in a shape of an annulus and the center of the annulus is shifted from the shaft section. Accordingly, the accumulation of the liquid formed on the opening edge can be further reliably spread and thinned.

In addition, it is preferable that the valve body and the seal member be two-color molded. Accordingly, the valve body, in which the bonding strength of the seal member is improved, is obtained.

It is preferable that the seal member be formed in a wave shape configured of a portion protruding to the shaft section side and a portion protruding outwardly further than the shaft section. Accordingly, the accumulation of the liquid formed on the opening edge can be further reliably spread and thinned.

In addition, it is preferable that the valve body and the seal member be integrally molded. Accordingly, the manufacturing of the valve body can be simplified.

It is preferable that the shaft section be provided with a screw which is pressed against the pressure receiving member and then rotates the valve body. Accordingly, the rotation of the valve body is promoted so that the accumulation of the liquid formed on the opening edge can be further reliably spread and thinned.

In addition, it is preferable that the water-repellent resin be silicon oil or fluorine resin. Accordingly, the silicon oil or the fluorine resin can be used as the water-repellent resin having water-repellency.

In addition, it is preferable that the valve body be provided with a groove which receives the pressure of the liquid in the liquid flow path and then rotates the valve body on the side surface thereof. Accordingly, the rotation of the valve body is promoted so that the accumulation of the liquid formed on the opening edge can be further reliably spread and thinned.

In addition, it is preferable that the liquid flow path include a valve body accommodating chamber which communicate with the communication path so as to accommodate the valve body, and the valve body accommodating chamber is provided with a groove in which the liquid circles from the valve body accommodating chamber to the communication path on the side surface thereof. Accordingly, the rotation of the valve body is promoted so that the accumulation of the liquid formed on the opening edge can be further reliably spread and thinned.

In addition, according to still another aspect of the invention, there is provided a liquid ejecting head including the flow path member; and a head main body ejecting the liquid supplied from the flow path member.

In the aspect, the liquid ejecting head is provided in which the ejection characteristics of the liquid are stable.

Further, according to still another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head.

In the aspect, the liquid ejecting apparatus is provided in which the ejection characteristics of the liquid are stable.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First Embodiment

Hereinafter, the invention is described in detail based on the embodiments. An ink jet type recording head is an example of a liquid ejecting head and simply referred to as a recording head. In addition, an ink jet type recording apparatus is an example of a liquid ejecting apparatus. Further, it is assumed that the directions shown by each arrow represented by “front”, “right” and “up” in each drawing indicates “front-back direction”, “right-left direction” and “up-down direction”, respectively.

FIG. 1is a plan view of an ink jet type recording apparatus. As shown inFIG. 1, an ink jet type recording apparatus11includes a body frame12having a rectangular shape in plan view. A platen13is extended in the right-left direction, which is a main scanning direction in the body frame12. On the platen13, a recording sheet (not shown) is fed by a paper feeding mechanism (not shown) along the front-back direction which is a sub-scanning direction. In addition, a rod-shaped guide shaft14which is extended parallel in the longitudinal direction (the right-left direction) of the platen13is provided in a hanging manner upward from the platen13in the body frame12.

A carriage15is supported on the guide shaft14in a state where reciprocating movement thereof is possible along the guide shaft14. The carriage15is connected to a carriage motor17, which is provided at a back surface of the body frame12, via an endless timing belt16hung between a pair of pulleys16awhich is provided in the inside of back wall of the body frame12. Accordingly, the carriage15is reciprocated along the guide shaft14by the drive of the carriage motor17.

A recording head18is supported at a lower end side facing the platen13in the carriage15. The recording head18includes a head body19ejecting the ink and a flow path member30supplying the ink from the ink cartridge22to the head body19.

Plural nozzles (not shown) are opened to the lower surface of a head body19. Ink droplets are ejected respectively from each nozzle to a recording paper (not shown) fed on the platen13by driving a piezoelectric element (not shown) provided in the head body19and then the printing is performed.

A carriage holder21is provided on a right end portion in the body frame12and plural ink cartridges22are detachably mounted on the carriage holder21as a liquid supply source. In the embodiment, five ink cartridges22are provided. Different (color) types of ink are accommodated in each ink cartridge22.

Each ink cartridge22mounted on the carriage holder21is connected to the flow path member30via each ink supply tube24. Each color of ink, which is supplied from the respective ink cartridges22via the respective ink supply tubes24, is temporarily stored in the flow path member30. Each color of ink temporarily stored individually is supplied to the head body19.

A maintenance unit26for performing maintenance such as cleaning of the head body19is provided at a home position region of the carriage15, that is at a position closer to the right end portion in the body frame12. The maintenance unit26includes a cap27which comes in contact with the head body19so as to surround the opening of each nozzle of the head body19and accommodates the ink ejected by flushing from the opening of each nozzle, and a suction pump (not shown) which is capable of suctioning the inside of the cap27.

Thus, thickened ink, bubbles or the like is forcibly discharged from the opening of each nozzle into the cap27, that is, a cleaning is performed, by suctioning the inside of the cap27using a suction pump (not shown) in a state where the head body19comes in contact with the cap27so as to surround the opening of each nozzle of the head body19.

FIG. 2is a plan view of the flow path member (in a state where a cover member and a film are removed) according to the embodiment,FIG. 3is a plan view of a first flow path member40according to the embodiment andFIG. 4is a cross-sectional view taken along the line IV-IV inFIG. 2.

As shown in the drawings, the flow path member30includes a square box-shaped holding member31having a bottom, a cover member32capable of sealing an upper opening of the holding member31, a first flow path member40and a second flow path member50which are received in the holding member31.

An inner bottom surface of the holding member31and a lower surface of the first flow path member40, an upper surface of the first flow path member40and a lower surface of the second flow path member50, and an upper surface of the holding member31and a lower surface of the cover member32are respectively bonded to each other by an adhesive. In addition, the holding member31, the cover member32, the first flow path member40and the second flow path member50have stiffness and are configured of a synthetic resin through which the liquid does not pass.

As shown inFIG. 3, plural filter chamber concave sections41are provided in the front end side (an end portion in the front direction) on the upper surface of the first flow path member40. In the embodiment, five filter chamber concave sections41are arranged in a line in the right-left direction depending on the type of ink used.

In addition, valve body concave sections43, in which valve bodies90(described in detail below) are disposed, are provided in a line in the right-left direction at the back end side in the inner bottom surface of the first flow path member40. In the embodiment, one valve body concave section43is provided on one filter chamber concave section41and a total of five valve body concave sections43is provided in a line in the right-left direction.

As shown inFIGS. 2 to 4, a filter chamber44and a valve body accommodating chamber46are formed by laminating the second flow path member50on the upper surface of the first flow path member40.

The filter chamber44is a space surrounded by each filter chamber concave sections41and the second flow path member50, and, in the embodiment, five filter chambers44are formed. In addition, the valve body accommodating chamber46is a space surrounded by the valve body concave sections43and the second flow path member50, and in the embodiment, five valve body accommodating chambers46are formed.

A filter45has substantially the same shape as the opening shape of the filter chamber concave sections41and is arranged so as to cross in the up-down direction in which the ink of the filter chamber concave section41flows. A foreign material or the like, which is included in each ink flowing from the upstream side, is removed using the filter45. In addition, the filter45may be formed by finely weaving metal or may be formed of a metal plate or a nonwoven fabric where fine single hole is provided.

An outlet hole47is opened to the bottom surface of each filter chamber44so as to drain the ink, in which the foreign material or the like is removed by the filter45, to the head body19(seeFIG. 1) side positioned at the downstream side. The outlet hole47communicates with a communicating hole33that is a through hole formed on the bottom surface of the holding member31, and the ink is drained to the head body19via the communicating hole33.

In addition, an ink introduction path48, in which the ink supplied from the ink supply tube24(seeFIG. 1) is introduced, is formed at the first flow path member40. An opening of one side of the ink introduction path48is formed on the upper surface of the first flow path member40and an opening of the other side is formed on the bottom surface of the valve body accommodating chamber46.

Five groove-shaped flow paths51, which configure a portion of the liquid flow path formed on the flow path member30, are extended in the front-back direction on the upper surface of the second flow path member50. In the embodiment, five groove-shaped flow paths51are provided having substantially the same length as each other in the front-back direction.

The groove-shaped flow path51is extended from a region facing the valve body accommodating chamber46of the second flow path member50to a region facing the filter chamber44. The back end side of the groove-shaped flow paths51communicates with the valve body accommodating chamber46via a communication path52. The front end side of the groove-shaped flow paths51communicates with the filter chamber44via the communication path55.

A film (a flexible member)60made of a synthetic resin having flexibility is provided on the upper surface of the second flow path member50.

The film60seals the upper opening of the groove-shaped flow paths51and a pressure chamber53is a space formed by the film60and the groove-shaped flow paths51. The region facing the groove-shaped flow paths51of the film60, in other words, the region configuring one surface of a pressure chamber53is referred to as a pressure receiving section61. The opening shapes of each of groove-shaped flow paths51are the same as each other so that the pressure receiving sections61also have the same shape as each other. The pressure receiving section61of the film60is elastically deformed by a difference between the atmosphere and the pressure in the pressure chamber53. Since the pressure in the pressure chamber53becomes negative with respect to the atmosphere, the pressure receiving section61is flexed to the inner side of the pressure chamber53.

In the embodiment, the film60is one sheet of film covering the entire upper surface of the second flow path member50. The film60is bonded to the opening edge of the groove-shaped flow paths51of the upper surface of the second flow path member50using adhesive70. Of course, the film60may be bonded to the entire upper surface of the second flow path member50using an adhesive, and not just the opening edge. In addition, film60does not need to be formed in one sheet and may be formed for each groove-shaped flow path51.

As described above, the liquid flow path configured of the ink introduction path48, the valve body accommodating chamber46, the communication path52, the pressure chamber53, the communication path55, the filter chamber44, the outlet hole47and the communicating hole33is provided on the flow path member30. The ink supplied from each ink supply tube24(seeFIG. 1) flows in the liquid flow path of the flow path member30and then is supplied to the head body19. In addition, the communication path52corresponds to a communication path communicating with the groove-shaped flow path (the pressure chamber) disclosed in the claims.

A pressure receiving member80is arranged between the second flow path member50and the film60. The pressure receiving member80is displaced by receiving a pressing force from the film due to the displacement of the film toward the pressure chamber53side and is intended to press a valve body90described below.

Specifically, the pressure receiving member80is configured of five operation plates81and a base end section82to which each of the operation plates81is commonly connected. The material of the pressure receiving member80is not specifically limited and in the embodiment, the pressure receiving member80is formed of one sheet of a thin plate made of a stainless steel having appropriate elasticity. The operation plates81is formed in such a manner that the width thereof is slightly narrower than that of the pressure chamber53and the length thereof is long in the front-back direction.

The pressure receiving member80is bonded to the upper surface of the second flow path member50at the base end section82and the upper surface thereof is covered by the film60. Thus, the base end section82of the pressure receiving member80is pinched between the second flow path member50and the cover member32. In addition, each of operation plates81is arranged so as to face the pressure receiving section61in plan view and is separated from the bottom portion of the groove-shaped flow paths51. In other words, the pressure receiving member80has a cantilever structure in which the base end section82is a fixed end and the operation plate81is a free end.

The valve body90is provided below the pressure receiving member80. The valve body90is configured in such a manner that it is possible for the valve body90to enter a valve closing state in which the ink does not flow in the pressure chamber53and enter a valve opening state in which the ink flows in the pressure chamber53, and the valve body90is biased so as to be in the valve closing state.

The valve body90is described in detail usingFIGS. 4 to 6B.FIGS. 5A and 5Bare a plan view and a cross-sectional view of the valve body, respectively, andFIGS. 6A and 6Bare cross-sectional views illustrating the opening-closing operation of the valve body, respectively.

As shown inFIG. 4, the valve body90includes a cylindrical shaft section91, a disc-shaped flange section92and a seal member93. The flange section92is an example of the valve main body in the aspects of the invention. The outer diameter of the shaft section91is smaller than the inner diameter of the communication path52and the shaft section91is inserted through the communication path52. In addition, the outer diameter of the flange section92is larger than the inner diameter of the communication path52and the flange section92is arranged in the valve body accommodating chamber46. The lower end of the shaft section91is connected to the center of the upper surface of the flange section92and the upper end of the shaft section91comes into contact with the lower surface of the operation plate81.

In addition, the film60does not need to come in constant contact with the operation plate81, and if the operation plate81is pressed due to the displacement of the film60, the film60and the operation plate81may be separated. Similarly, if the valve body90is pressed due to the displacement of the operation plate81, the operation plate81does not need to come in contact with the valve body90and they may be separated.

As shown inFIGS. 5A and 5B, the seal member93which is configured of elastic material is fixed to the upper surface of the flange section92. The seal member93comes in contact with an opening edge52a(seeFIG. 4) of the communication path52and performs sealing between the flange section92and the opening edge52a. The seal member93is formed in a shape of an annulus of which the distance from the shaft section91is not constant. That is, as shown inFIG. 5A, the seal member93is continued without a break so as to surround the shaft section91and the distance from the shaft section91is not constant. In other words, the seal member93is formed in the shape of the annulus concentric with the shaft section91. In addition, the height (the height from the upper surface of the flange section92) of the seal member93is constant. In the embodiment, the seal member93is formed in an oval shape so as to surround the shaft section91. Since the seal member93has such a shape, the ink can be prevented from being accumulated on the opening edge52aas described below in detail.

Furthermore, the seal member93passes through the shaft section91on the upper surface of the flange section92that is a plane perpendicular to the shaft section91and is formed to be line symmetrical with respect to two axes (one is illustrated in the line VB-VB and the other is perpendicular to the line VB-VB) which are perpendicular to each other. The seal member93has a shape such that a bias force by a coil spring94is applied constantly to the entire seal member93and sealing with the opening edge52acan be improved as described in detail below.

In addition, as shown inFIGS. 4 and 5B, the coil spring94which is an example of a biasing member is intervened between the lower surface of the flange section92and the bottom surface of the valve body accommodating chamber46. One end of the coil spring94is fixed to the bottom surface of the valve body accommodating chamber46and the other end thereof is engaged in a groove95provided on the lower surface of the flange section92. The groove95is formed in a circular shape around the shaft section91. The flange section92is slidably formed with respect to the coil spring94. Accordingly, the entire valve body90can move up and down due to the expansion and contraction of the coil spring94, and is rotatably formed around the shaft section91.

The opening-closing operation of the valve body90having such a configuration is described. As shown inFIG. 6A, the coil spring94is biased in an upward direction which makes the valve body90always be in the valve closing state. Thus, in the valve closing state of the valve body90, the seal member93closely comes in contact with the opening edge52aof the communication path52in a state of surrounding the communication path52. Accordingly, the communication path52is closed, that is, the inside of the valve body accommodating chamber46and the inside of the pressure chamber53are in a non-communication state. Further, as described above, since the seal member93is formed so as to be line symmetrical with respect to two axes perpendicular to each other (seeFIGS. 5A and 5B), the bias force of the coil spring94is applied constantly to the entire seal member93and the sealing with the opening edge52ais improved.

In a state where the ink is supplied to the liquid flow path due to initial charging or the preceding ejecting of the ink, when each ink is ejected from the head body19(seeFIG. 1), the ink in each pressure chamber53decreases. Accordingly, each pressure chamber53becomes a negative pressure due to the pressure difference with the atmosphere, and then the pressure receiving section61(seeFIG. 4) is displaced to be bent to the pressure chamber53side (the lower side). Each operation plate81(seeFIG. 4) is pressed by the pressure receiving section61and then is elastically deformed. Further, each valve body90is pressed by the operation plate81and then pushed down.

As shown inFIG. 6B, when the valve body90is pushed down against the bias force of the pressure coil spring94, the valve body90becomes the valve opening state. In other words, the seal member93is separated from the opening edge52aand then the valve body90is opened. Thus, when the valve body90is in the valve opening state, the communication path52is opened, that is, the inside of the valve body accommodating chamber46and the inside of the pressure chamber53enter the communication state.

When the valve body90is the valve opening state, the ink in each valve body accommodating chamber46flows in each pressure chamber53via the communication path52. Thus, when the ink is sufficiently replenished in each pressure chamber53, the negative pressure in each pressure chamber53is eliminated and then each pressure receiving section61and each operation plate81return to their respective original positions. In addition, each valve body90is in the valve closing state respectively due to the bias force of each coil spring94and then each pressure chamber53is always maintained at a constant pressure.

Here, it that accumulation of the ink on the opening edge52acan be suppressed using the seal member93described above is described in detail.FIGS. 7A,7C and8A are plan views of the communication path52communicating with the pressure chamber53seen from the valve body accommodating chamber46side.FIG. 7Bis a cross-sectional view taken along the line VIIB-VIIB inFIG. 7A,FIG. 8Bis a cross-sectional view taken along the line VIIIB-VIIIB inFIG. 8A.

First, as shown inFIGS. 7A and 7B, the seal member93(seeFIGS. 5A and 5B) comes in contact with the opening edge52adue to the opening-closing operation of the valve body90(seeFIGS. 4 to 6B). As described above, since the seal member93is formed in an oval shape, the ink begins to be accumulated in the same shape as the oval shape thereof on the opening edge52a. The ink accumulated on the opening edge52ais referred to as accumulated ink96.

As described above, the valve body90is rotatably formed around the shaft section91. Accordingly, the valve body90is slightly rotated whenever the valve body90performs the opening-closing operation (the up-down movement) and the seal member93is also rotated due to the rotation of the valve body90. Since the seal member93is formed in an oval shape, as shown inFIG. 7C, the position of the accumulated ink96, which is accumulated in a position where the seal member93comes in contact with the opening edge52a, is different from the position shown inFIG. 7A. In the example shown inFIG. 7C, the accumulated ink96is formed in the oval shape of which the long axis is extended from the upper right to the lower left.

Hereinafter, as shown inFIGS. 8A and 8B, since the valve body90is rotated whenever the valve body90repeats the opening-closing operation, the accumulated ink96formed using the seal member93, which is rotated, can be relatively spread and thinned. As shown inFIG. 8A, the accumulated ink96is formed in a donut shape around the communication path52. The radius of the outer periphery thereof is the radius RL of the long axis of the oval-shaped seal member93and the radius of the inner periphery thereof is the radius RS of the short axis of the seal member93.

If the seal member93is formed in the shape of the annulus around the shaft section91, in other words, when the seal member93is formed in the shape of the annulus in which the distance from the shaft section91is constant, the accumulated ink96is formed as shown inFIGS. 9A and 9B.FIG. 9Ais a plan view of communication path52communicating with the pressure chamber53seen from the valve body accommodating chamber46side andFIG. 9Bis a cross-sectional view taken along the line IXB-IXB inFIG. 9A.

As shown inFIG. 9A, when the seal member93is formed in the annular shape of the annulus around the shaft section91, the accumulated ink96formed on the opening edge52ais also formed in the shape of the annulus. Since the distance from the shaft section91of the seal member93is constant, even though the valve body90is rotated, the accumulated ink96is continuously accumulated in the same position. Accordingly, as shown inFIGS. 9A and 9B, the accumulated ink is accumulated relatively thick and narrow. Thus, there is a variation in the opening-closing operation of the valve body90. For example, even though the degrees of pressure fluctuations inside of the pressure chamber53are the same as each other, since the accumulated ink96is formed relatively thick, the degrees of the opening of the valve body90become different from each other. As a result, the supply of the ink to the head body19is unstable, ejection characteristics of the ink vary and printing quality is degraded. In addition, when accumulation of the ink is further advanced, as shown inFIG. 9B, the variation of the thickness of the accumulated ink96becomes significant and even when the valve body90closes the communication path, the sealing is incomplete due to the seal member93. In this case, there is concern of the ink flowing in the pressure chamber53from the valve body accommodating chamber46and the ink being ejected from the nozzles of the head body19at an unintended timing.

Meanwhile, as described above, in the flow path member30according to the invention, the seal member93is formed in the shape of the annulus of which the distance from the shaft section91is not constant. Thus, as shown inFIGS. 7A to 8B, even though the ink is accumulated on the opening edge52a, the ink spreads in the width direction. In other words, since the accumulated ink96spreads at the region between the circle having the radius RL and the circle having the radius RS, the ink is suppressed from being accumulated in the thickness direction. Accordingly, it is possible to almost completely eliminate the influence of the accumulated ink96with respect to the opening-closing operation of the valve body90in the communication path52.

Accordingly, the flow path member30is configured in such a manner that the variation does not occur in the opening-closing operation of the valve body90, the operation of the valve body90can be stable and the ink can be stably supplied to the head body19.

Thus, according to the recording head18and the ink jet type recording apparatus11including the flow path member30and the head body19, since the ink is stably supplied to the head body19using the flow path member30as described above, the variation in the ejecting speed of the ink ejected from the nozzle or in the weight of the ink droplets which are ejected via each liquid path can be suppressed. Accordingly, the ejection characteristics of the ink are improved so that the recording head18and the ink jet type recording apparatus11, which can perform high quality printing, is provided.

Second Embodiment

In the first embodiment, the seal member93, which is formed in the shape of the annulus of which the distance is not constant from the shaft section91, is exemplified as the seal member having an oval shape. However, the seal member93is not limited to the shape. Below, other embodiments of the seal member are described. In addition, the same numbers are applied to the same members as in the first embodiment and the duplicated descriptions are omitted.

FIG. 10is a plan view of the valve body. A seal member93A is formed in the shape of the annulus so as to surround the shaft section91. The center of the seal member93A is shifted from the shaft section91. In other words, the center of the seal member93A is eccentric from the shaft section91.

When the seal member93A is rotated due to the rotation of the valve body90, the trace of the seal member93A is shown in dotted lines. The inside dotted line is a circle having the radius RS which is the shortest distance between the shaft section91and the seal member93A, and an outside dotted line is a circle having the radius RL which is the longest distance between the shaft section91and the seal member93A. Accordingly, a region between two circles is a region where the upper surface of the seal member93A passes through and accumulated ink96is formed on the opening edge52afacing the region.

As described above, the seal member93A is formed in the shape of the annulus of which the distance from the shaft section91is not constant. Accordingly, similar to the first embodiment, even though the ink is accumulated on the opening edge52a, the ink spreads in the width direction. In other words, the accumulated ink96spreads at the region between the circle having the radius RL and the circle having the radius RS so that the ink is suppressed from being accumulated in the thickness direction. Accordingly, the influence of the accumulated ink96can be almost completely eliminated with respect to the operation in which the valve body90opens and closes the communication path52.

Accordingly, the flow path member30is configured so that the operation of the valve body90can be stable without the occurrence of variation in the opening-closing operation of the valve body90and the ink can be stably supplied to the head body19.

FIGS. 11A and 11Bare plan views of the valve body. As shown inFIG. 11A, a seal member93B is formed in a wave shape so as to surround the shaft section91. In other words, the seal member93B is formed in a wave shape configured of eight portions protruding to the shaft section91side and eight portions protruding from the shaft section91to the outside. In addition, the seal member93B is line symmetrical with respect to two axes (not shown, similar to the dotted lines inFIG. 5) perpendicular to each other, which pass through the shaft section91(not shown, the same dotted line asFIG. 5A) on the upper surface of the flange section92that is a plane perpendicular to the shaft section91.

When the seal member93B is rotated due to the rotation of the valve body90, a trace of the seal member93B is shown in dotted lines. The inside dotted line is a circle having the radius RS which is the shortest distance between the shaft section91and the seal member93B, and the outside dotted line is a circle having the radius RL which is the longest distance between the shaft section91and the seal member93B. Accordingly, the region between two circles is a region where the upper surface of the seal member93B passes through and accumulated ink96is formed on the opening edge52afacing the region.

As described above, the seal member93B is formed in the shape of the annulus of which the distance from the shaft section91is not constant. Accordingly, similar to the first embodiment, even though the ink is accumulated on the opening edge52a, the ink spreads in the thickness direction. In other words, the accumulated ink96spreads at the region between the circle having the radius RL and the circle having the radius RS so that the ink is suppressed from being accumulated in the width direction. Accordingly, the influence of the accumulated ink96can be almost completely eliminated with respect to the operation in which the valve body90opens and closes the communication path52.

Accordingly, the flow path member30is configured so that the operation of the valve body90can be stable without occurrence of the variation in the opening-closing operation of the valve body90and the ink can be stably supplied to the head body19.

In addition, since the seal member93B is formed line symmetrical with respect to two axes (not shown) perpendicular to each other, the bias force of the coil spring94is applied evenly to the entire seal member93B and the sealing property with the opening edge52ais improved.

As shown inFIG. 11B, a seal member93C may be formed in a wave shape in which a center portion of each side having substantially rectangular shape is protruded to the shaft section91side. Even in such a shape, the same function effect as the seal member93B shown inFIG. 11Ais achieved.

Third Embodiment

In the first embodiment, the valve body90is rotated due to the up-down movement of the valve body90and the flow path member30may have a structure to promote the rotation of the valve body90.

FIGS. 12 to 14are cross-sectional views of a main portion for describing the opening-closing operation of the valve body having a screw. In addition, the same numbers are applied to the same members in the first embodiment and the duplicated descriptions are omitted.

The valve body90according to the embodiment has a screw97which is pressed by the pressure receiving member80(the operation plate81) to the shaft section91and rotates the valve body90. The screw97is a member which is formed in a spiral shape around the shaft section91. In the embodiment, the screw97turns four times around the screw91and the top stage thereof comes in contact with the operation plate81.

As shown inFIG. 13, the inside of the pressure chamber53becomes the negative pressure and when the film60is bent to the pressure chamber53side, the operation plate81is pressed by the film60and then is elastically deformed to the pressure chamber53side. The screw97is pressed by the elastic deformation of the operation plate81and the screw97rotates around the shaft section91due to the pressing force.

As described above, since the valve body90is rotated whenever the valve body90performs the up-down movement by providing the screw97, the accumulated ink96formed by the seal member93can be further reliably spread and thinned.

In addition, as shown inFIG. 14, a protrusion section98, which protrudes to the screw97side, may be provided on the operation plate81. The pressing of the screw97according to the flexible deformation of the operation plate81can be further reliably performed by providing the protrusion section98on the operation plate81.

Fourth Embodiment

In the third embodiment, in order to promote the rotation of the valve body90, the pressing force of the operation plate81is acted on the valve body90and then the rotation thereof is promoted directly, however, the invention is not limited to the embodiment.

FIG. 15is a cross-sectional view of a main portion illustrating the valve body and the valve body accommodating chamber. In addition, the same numbers are applied to the same members in the first embodiment and the duplicated descriptions are omitted. In addition, the seal member93, the coil spring94and the like are not shown in the drawing.

As shown in the same drawing, a groove99, which receives the pressure of the ink and rotates the valve body90, is provided on the side surface of the flange section92that is the side surface of the valve body90. Specifically, the groove99is extended perpendicular to the shaft section91, rather than in a direction parallel to the shaft section91.

As described above, the ink, which flows from the valve body accommodating chamber46to the communication path52, flows into the groove99by providing the groove99on the side surface of the flange section92. Thus, the pressure of the ink presses the side surface of the groove99and then the valve body90is rotated. As described above, the valve body90is rotated by the pressure of the ink flowed in the groove99so that the accumulated ink96formed by the seal member93can be further reliably spread and thinned.

Furthermore, a groove46a, which makes the ink to be circled from the valve body accommodating chamber46to the communication path52, may be provided on the side surface of the valve body accommodating chamber46. Specifically, the spiral groove46ais provided on the side surface of the valve body accommodating chamber46.

The ink, which flows from the valve body accommodating chamber46to the communication path52, is circled by providing the groove46aon the side surface of the valve body accommodating chamber46. The valve body90is rotated by the circling flow of the ink. As described above, the valve body90is rotated by the circling flow of the ink, which is produced by the groove46aso that the accumulated ink96, which is formed by the seal member93, can be further reliably spread and thinned.

Fifth Embodiment

In the first embodiment, the seal member93, which is formed in the shape of the annulus of which the distance is not constant from the shaft section91, is exemplified as the seal member having an oval shape. However, the seal member93is not limited to this shape. For example, the shape shown inFIG. 16may be provided. Furthermore, other embodiments of the seal member are described below.

FIG. 1is a plan view of an ink jet type recording apparatus. As shown inFIG. 1, an ink jet type recording apparatus11includes a body frame12having a rectangular shape in plan view. A platen13is extended in the right-left direction which is a main scanning direction in the body frame12. On the platen13, a recording sheet (not shown) is fed by a paper feeding mechanism (not shown) along the front-back direction which is a sub-scanning direction. In addition, a rod-shaped guide shaft14, which is extended parallel in the longitudinal direction (the right-left direction) of the platen13, is provided in a hanging manner at the upper side of the platen13in the body frame12.

A carriage15is supported on the guide shaft14in a state where reciprocating movement thereof is possible along the guide shaft14. The carriage15is connected to a carriage motor17, which is provided at a back surface of the body frame12, via an endless timing belt16hung between a pair of pulleys16awhich is provided in the inside of back wall of the body frame12. Accordingly, the carriage15is reciprocated along the guide shaft14by the drive of the carriage motor17.

A recording head18is supported at a lower end side facing the platen13in the carriage15. The recording head18includes a head body19ejecting the ink and a flow path member30supplying the ink from the ink cartridge22to the head body19.

Plural nozzles (not shown) are opened to the lower surface of a head body19. Ink droplets are ejected respectively from each nozzle to a recording paper (not shown) fed on the platen13by driving a piezoelectric element (not shown) provided in the head body19and then the printing is performed.

A carriage holder21is provided on a right end portion in the body frame12and plural ink cartridges22are detachably mounted on the carriage holder21as a liquid supply source. In the embodiment, five ink cartridges22are provided. Different (color) types of ink are accommodated in each ink cartridge22.

Each ink cartridge22mounted on the carriage holder21is connected to the flow path member30via each ink supply tube24. Each color of ink, which is supplied from each ink cartridge22via each ink supply tube24, is temporarily stored in the flow path member30. Each color of ink temporarily stored individually is supplied to the head body19.

A maintenance unit26for performing maintenance such as cleaning of the head body19is provided at a home position region of the carriage15, that is, at a position closer to the right end portion in the body frame12. The maintenance unit26includes a cap27which comes in contact with the head body19so as to surround the opening of each nozzle of the head body19and accommodates the ink ejected by flushing from the opening of each nozzle, and a suction pump (not shown) which is capable of suctioning the inside of the cap27.

Thus, thickened ink, bubbles or the like is forcibly discharged from the opening of each nozzle into the cap27, that is, a so-called cleaning is performed, by suctioning the inside of the cap27using a suction pump (not shown) in a state where the head body19comes in contact with the cap27so as to surround the opening of each nozzle of the head body19.

FIG. 2is a plan view of the flow path member (in a state where a cover member and a film are removed) according to the embodiment,FIG. 3is a plan view of a first flow path member40according to the embodiment andFIG. 4is a cross-sectional view taken along the line IV-IV inFIG. 2.

As shown in the drawings, the flow path member30includes a square box-shaped holding member31having a bottom, a cover member32capable of sealing an upper opening of the holding member31, a first flow path member40and a second flow path member50which are received in the holding member31.

An inner bottom surface of the holding member31and a lower surface of the first flow path member40, an upper surface of the first flow path member40and a lower surface of the second flow path member50, and an upper surface of the holding member31and a lower surface of the cover member32are respectively bonded to each other by an adhesive. In addition, the holding member31, the cover member32, the first flow path member40and the second flow path member50have stiffness and are configured of a synthetic resin through which the liquid does not pass.

As shown inFIG. 3, plural filter chamber concave sections41are provided in the front end side (an end portion in the front direction) on the upper surface of the first flow path member40. In the embodiment, five filter chamber concave sections41are arranged in a line in the right-left direction depending on the type of ink used.

In addition, valve body concave sections43, in which valve bodies90(described in detail below) are disposed, are provided in a line in the right-left direction at the back end side (at end portion in the back direction) in the inner bottom surface of the first flow path member40. In the embodiment, one valve body concave section43is provided on one filter chamber concave section41and a total of five valve body concave sections43is provided in a line in the right-left direction.

As shown inFIGS. 2 to 4, a filter chamber44and a valve body accommodating chamber46are formed by laminating the second flow path member50on the upper surface of the first flow path member40.

The filter chamber44is a space surrounded by each filter chamber concave sections41and the second flow path member50, and in the embodiment, five filter chambers44are formed. In addition, the valve body accommodating chamber46is a space surrounded by the valve body concave sections43and the second flow path member50, and in the embodiment, five valve body accommodating chambers46are formed.

A filter45has substantially the same shape as the opening shape of the filter chamber concave sections41and is arranged so as to cross in the up-down direction in which the ink of the filter chamber concave section41flows. A foreign material or the like, which is included in each ink flowing from the upstream side, is removed using the filter45. In addition, the filter45may be formed by finely weaving metal or may be formed of a metal plate or a nonwoven fabric where fine single hole is provided.

An outlet hole47is opened to the bottom surface of each filter chamber44so as to drain the ink, in which the foreign material or the like is removed by the filter45, to the head body19(seeFIG. 1) side positioned at the downstream side. The outlet hole47communicates with a communicating hole33that is a through hole formed on the bottom surface of the holding member31, and the ink is drained to the head body19via the communicating hole33.

In addition, an ink introduction path48, in which the ink supplied from the ink supply tube24(seeFIG. 1) is introduced, is formed at the first flow path member40. An opening of one side of the ink introduction path48is formed on the upper surface of the first flow path member40and an opening of the other side is formed on the bottom surface of the valve body accommodating chamber46.

Five groove-shaped flow paths51, which configure a portion of the liquid flow path formed on the flow path member30, are extended in the front-back direction on the upper surface of the second flow path member50. In the embodiment, five groove-shaped flow paths51are provided having substantially the same length as each other in the front-back direction.

The groove-shaped flow path51is extended from a region facing the valve body accommodating chamber46of the second flow path member50to a region facing the filter chamber44. The back end side of the groove-shaped flow paths51communicates with the valve body accommodating chamber46via a communication path52. The front end side of the groove-shaped flow paths51communicates with the filter chamber44via the communication path55.

A film (a flexible member)60made of a synthetic resin having flexibility is provided on the upper surface of the second flow path member50.

The film60seals the upper opening of the groove-shaped flow paths51and a pressure chamber53is a space formed by the film60and the groove-shaped flow paths51. The region facing the groove-shaped flow paths51of the film60, in other words, the region configuring one surface of a pressure chamber53is referred to as a pressure receiving section61. The opening shapes of each of groove-shaped flow paths51are the same as each other so that the pressure receiving sections61also have the same shape as each other. The pressure receiving section61of the film60is elastically deformed by difference between the atmosphere and the pressure in the pressure chamber53. Since the pressure in the pressure chamber53becomes negative with respect to the atmosphere, the pressure receiving section61is flexed to the inner side of the pressure chamber53.

In the embodiment, the film60is one sheet of film covering the entire upper surface of the second flow path member50. The film60is bonded to the opening edge of the groove-shaped flow paths51of the upper surface of the second flow path member50using an adhesive70. Of course, the film60may be bonded to the entire upper surface of the second flow path member50using an adhesive, and not just the opening edge. In addition, the film60does not need to be formed in one sheet and may be formed for each groove-shaped flow path51.

As described above, the liquid flow path configured of the ink introduction path48, the valve body accommodating chamber46, the communication path52, the pressure chamber53, the communication path55, the filter chamber44, the outlet hole47and the communicating hole33is provided on the flow path member30. The ink supplied from each ink supply tube24(seeFIG. 1) flows in the liquid flow path of the flow path member30and then is supplied to the head body19. In addition, the communication path52corresponds to a communication path communicating with the groove-shaped flow path (the pressure chamber) disclosed in the claims.

A pressure receiving member80is arranged between the second flow path member50and the film60. The pressure receiving member80is displaced by receiving a pressing force from the film due to the displacement of the film toward the pressure chamber53side and is intended to press a valve body90described below.

Specifically, the pressure receiving member80is configured of five operation plates81and a base end section82to which each of the operation plates81is commonly connected. The material of the pressure receiving member80is not specifically limited and in the embodiment, the pressure receiving member80is formed of one sheet of a thin plate made of a stainless steel having appropriate elasticity. The operation plates81is formed in such a manner that the width thereof is slightly narrower than that of the pressure chamber53and the length thereof is long in the front-back direction.

The pressure receiving member80is bonded to the upper surface of the second flow path member50at the base end section82and the upper surface thereof is covered by the film60. Thus, the base end section82of the pressure receiving member80is pinched between the second flow path member50and the cover member32. In addition, each of operation plates81is arranged so as to face the pressure receiving section61in plan view and is separated from the bottom portion of the groove-shaped flow paths51. In other words, the pressure receiving member80has a cantilever structure in which the base end section82is a fixed end and the operation plate81is a free end.

The valve body90is provided below the pressure receiving member80. The valve body90is configured in such a manner that it is possible for the valve body90to enter a valve closing state in which the ink does not flow in the pressure chamber53and enter a valve opening state in which the ink flows in the pressure chamber53, and the valve body90is biased so as to be in the valve closing state.

The valve body90is described in detail usingFIGS. 4 to 6andFIGS. 16A and 16B.FIGS. 5A and 5B, andFIGS. 16A and 16Bare a plan view and a cross-sectional view of the valve body, respectively, andFIGS. 6A and 6Bare cross-sectional views of a main portion of illustrating the opening-closing operation of the valve body, respectively.

As shown inFIG. 4, the valve body90includes a cylindrical shaft section91, a disc-shaped flange section92and a seal member93. The flange section92is an example of the valve main body in the claims. The outer diameter of the shaft section91is smaller than the inner diameter of the communication path52and the shaft section91is inserted through the communication path52. In addition, the outer diameter of the flange section92is larger than the inner diameter of the communication path52and the flange section92is arranged in the valve body accommodating chamber46. The lower end of the shaft section91is connected to the center of the upper surface of the flange section92and the upper end of the shaft section91comes in contact with the lower surface of the operation plate81. The material of the valve body90is not particularly limited and for example, it may be formed from a synthetic resin. In addition, the shaft section91and the flange section92may be integrally formed, or may be separately formed and then these may be bonded.

In addition, the film60does not need to come in constant contact with the operation plate81, and if the operation plate81is pressed due to the displacement of the film60, the film60and the operation plate81may be separated. Similarly, if the valve body90is pressed due to the displacement of the operation plate81, the operation plate81does not need to come in contact with the valve body90and they may be separated.

As shown inFIGS. 5A and 5B,16A and16B, the seal member93is fixed to the upper surface of the flange section92. The seal member93is continued without a break so as to surround the shaft section91and is formed in the shape of the annulus around the shaft section91. In addition, the height (the height from the upper surface of the flange section92) of the seal member93is constant.

The seal member93is mainly formed of the elastic material and when the valve body90is the valve closing state, the seal member93comes in contact with the opening edge52a(seeFIG. 4) of the communication path52, and seals between the flange section92and the opening edge52a. In addition, the material of the seal member93or the like is described in detail below.

In addition, as shown inFIGS. 4,5B and16B, the coil spring94, which is an example of a biasing member, is intervened between the lower surface of the flange section92and the bottom surface of the valve body accommodating chamber46. One end of the coil spring94is fixed to the bottom surface of the valve body accommodating chamber46and the other end thereof is fit to a groove95provided on the lower surface of the flange section92. Accordingly, the entire valve body90can move up and down due to the expansion and contraction of the coil spring94.

The opening-closing operation of the valve body90having such a configuration is described. As shown inFIG. 6A, the coil spring94is biased upwards which makes the valve body90to always be in the valve closing state. Thus, in the valve closing state of the valve body90, the seal member93closely comes in contact with the opening edge52aof the communication path52in a state of surrounding the communication path52. Accordingly, the communication path52is closed, that is, the inside of the valve body accommodating chamber46and the inside of the pressure chamber53are in a non-communication state. As described above, the seal member93are mainly formed of the elastic material. Thus, the seal member93comes in close contact with the opening edge52aby the elasticity so that the non-communication state can be reliably maintained.

In a state where the ink is supplied to the liquid flow path with initial charging or with ejecting of the ink before present time, when each ink is ejected from the head body19(seeFIG. 1), the ink in each pressure chamber53decreases. Accordingly, each pressure chamber53becomes a negative pressure due to the pressure difference with the atmosphere, and then the pressure receiving section61(seeFIG. 4) is displaced to be bent to the pressure chamber53side (the lower side). Each operation plate81(seeFIG. 4) is pressed by the pressure receiving section61and then is elastically deformed. Further, each valve body90is pressed by the operation plate81and then each valve body90is pushed down.

As shown inFIG. 6B, when the valve body90is pushed down against the bias force of the pressure coil spring94, the valve body90becomes the valve opening state. In other words, the seal member93is separated from the opening edge52aand then the valve body90is opened. Thus, when the valve body90is the valve opening state, the communication path52is opened, that is, the inside of the valve body accommodating chamber46and the inside of the pressure chamber53become the communication state.

When the valve body90is the valve opening state, the ink in each valve body accommodating chamber46flows in each pressure chamber53via the communication path52. Thus, when the ink is sufficiently replenished in each pressure chamber53, the negative pressure in each pressure chamber53is eliminated and then each pressure receiving section61and each operation plate81return to their respective original positions. In addition, each valve body90is the valve closing state respectively due to the bias force of each coil spring94and then each pressure chamber53is always maintained at a constant pressure.

Here, the seal member93is described in detail. The seal member93is formed including an elastic material and a water-repellent resin. The elastic material may include an elastomer. Of course, the material is not limited to the elastomer and may use a resin having an elastic modulus lower than that of the resin which forms the valve body90such as the flange section92and the shaft section91.

Meanwhile, the water-repellent resin may include silicon oil or a fluorine resin. Both the silicon oil and the fluorine resin have water-repellency with respect to the ink (the liquid). The water-repellent resin is kneaded in the elastic material and is molded as the seal member93. The water-repellent resin has a property to be dissociated to the outside due to the pressure applied to the seal member93.

In addition, it is preferable that the contact angle of the water-repellent resin with the ink be 60 degrees or greater. It is preferable that the water-repellent resin according to the invention have the contact angle at least equal to or greater than the contact angle of the surface of the valve body90side of the second flow path member50, that is, the surface of the opening edge52afacing the seal member93.

The valve body90described above may be formed by two-color molding with the shaft section91and the flange section92formed from a synthetic resin, and the seal member93formed from the elastic material and the water-repellent resin. Accordingly, the valve body90, in which a bonding strength between the seal member93and the flange section92is improved, may be obtained. In addition, the valve body90is not limited to the embodiments described above and the shaft section91, the flange section92and the seal member93may also be integrally molded with the elastic material and the water-repellent resin as a raw material. Accordingly, the production of the valve body90can be simplified. Of course, the seal member93and the flange section92are formed separately and then the valve body90may be formed by bonding the seal member93and the flange section92. In addition, the silicon oil and the fluorine resin may be kneaded into the elastic material independently and respectively, and these may be combined thereby kneading into the elastic material.

That accumulation of the ink on the opening edge52ais suppressed by the seal member93described above is described in detail.FIG. 17Ais a plan view of the communication path52communicating with the pressure chamber53, which is seen from the valve body accommodating chamber46side,FIG. 17Bis a cross-sectional view taken along the line XVIIB-XVIIB inFIG. 17A.

As shown inFIGS. 17A and 17B, the seal member93(seeFIGS. 5A and 5B) comes in contact with the opening edge52aby the opening-closing operation of the valve body90(seeFIGS. 4 to 6B). As described above, the seal member93is formed including the water-repellent resin and the water-repellent resin to be dissociated to the outside due to the pressure applied to the seal member93. Accordingly, the water-repellent resin to be dissociated from the seal member93which is pressed to the opening edge52adue to the bias force of the coil spring94. The dissociated water-repellent resin is attached to the opening edge52aside.

Hereinafter, the water-repellent resin to be dissociated from the seal member93is continuously attached to the opening edge52awhenever the valve body90repeats the opening-closing operation. As a result, the water-repellent resin to be dissociated from the seal member93is attached to the opening edge52ain the same shape as the annular seal member93. The water-repellent resin attached to the opening edge52ais referred to as an attached resin96.

The annular attached resin96is formed at the region facing the seal member93of the opening edge52a. The attached resin96, that is, the water-repellent resin has water-repellency with respect to the ink so that due to the water-repellent resin, the surface of the opening edge52ahas the same effect as that in which the water-repellent treatment is performed by the water-repellent resin. As described above, since the surface of the opening edge52ais covered by the water-repellent resin, it is possible to prevent the ink from adhering to the surface of the opening edge52a.

Supposedly, when the seal member93does not include the water-repellent resin, as shown inFIGS. 18A and 18B, the ink is accumulated on the opening edge52a. The accumulated ink is referred to as an accumulated ink96.FIG. 18Ais a plan view of the communication path52communicating with the pressure chamber53, which is seen from the valve body accommodating chamber46side andFIG. 18Bis a cross-sectional view taken along the line XVIIIB-XVIIIB.

As shown inFIGS. 18A and 18B, when the seal member93is repeatedly contacted and separated from the opening edge52aby the opening-closing operation of the valve body90, since water-repellency is applied to the opening edge52a, the ink begins to be gradually fixed. Furthermore, when the opening-closing operation of the valve body90is repeated, the ink is accumulated relatively thick and narrow.

Thus, variation occurs in the opening-closing operation of the valve body90. For example, even though degrees of the pressure variation inside the pressure chamber53are the same as each other, since the accumulated ink96is formed relatively thick, the opening degrees of the valve body90are different to each other. As a result, the supply of the ink to the head body19is unstable, the ejection property of the ink is varied and the printing quality is degraded. In addition, when the accumulation of the ink is further advanced, as shown inFIG. 18B, the variation of the thickness of the accumulated ink96becomes significant and even when the valve body90closes the communication path; the sealing is incomplete due to the seal member93. In this case, there is concern that the ink may flow in the pressure chamber53from the valve body accommodating chamber46and the ink may be discharged from the nozzles of the head body19at an unintended timing.

Meanwhile, as described above, in the flow path member30according to the invention, since the seal member93is formed including the water-repellent resin, the water-repellent resin is attached to the opening edge52afacing the seal member93by the opening-closing operation of the valve body90. Thus, as shown inFIGS. 7A to 7C, ink attaching to the opening edge52ais suppressed. Accordingly, it is possible to almost completely eliminate the influence of the accumulated ink96with respect to the opening-closing operation of the valve body90.

Accordingly, the flow path member30is configured in such a manner that the variation does not occur in the opening-closing operation of the valve body90, the operation of the valve body90can be stable and the ink can be stably supplied to the head body19.

Thus, according to the recording head18and the ink jet type recording apparatus11including the flow path member30and the head body19, since the ink is stably supplied to the head body19using the flow path member30as described above, the variation in the ejecting speed of the ink ejected from the nozzle or in the weight of the ink droplets which are ejected via each liquid flow path can be suppressed. Accordingly, the ejection characteristics of the ink are improved so that the recording head18and the ink jet type recording apparatus11, which can perform high quality printing, is provided.

In addition, since the flow path member30according to the invention includes the water-repellent resin in the seal member93, the water-repellent treatment may be unnecessary on the opening edge52aof the second flow path member50facing the seal member93.

For example, there is a need to mask on a portion where the water-repellent treatment is not performed when the water-repellent treatment is performed only on the opening edge52aof the second flow path member50. In this case, for the process of formation of the second flow path member50, the masking treatment and the water-repellent treatment on the second flow path member50are newly required. Meanwhile, when the masking treatment is omitted and the water-repellent treatment is performed the entire surface of the second flow path member50including the surface of the opening edge52a, the water-repellent treatment is also performed on an unnecessary portion.

In the invention, since it is unnecessary to perform the water-repellent treatment on the opening edge52aof the second flow path member50facing the seal member93, cost or labor relating to the formation of the flow path member30can be reduced.

In addition, the water-repellent treatment may be performed on the opening edge52aof the second flow path member50facing the seal member93. In this case, the ink becoming fixed to the opening edge52acan be further reliably prevented by applying the water-repellent treatment in advance on the opening edge52aand by attaching the water-repellent resin to be dissociated from the seal member93to the opening edge52a.

Other Embodiments

The ink used in the invention is not particularly limited and both pigment-based ink and dye-based ink can be applied to the invention. In addition, even though the liquid other than the ink is used, the liquid can be applied to the invention if the liquid is accumulated on the opening edge52aof the communication path52by the opening-closing operation of the valve body90.

In addition, in the ink jet type recording apparatus11, it is exemplified that the recording head18is mounted on the carriage15and moves in the main scanning direction, however, the invention is not particularly limited to the embodiment. For example, the invention may be applied to a so-called line-type recording apparatus in which the printing is performed by fixing the recording head18and by moving only the recording sheet such as a paper in the sub-scanning direction.

In addition, in each of embodiments described above, the ink jet type recording head as an example of the liquid ejecting head and the ink jet type recording apparatus as an example of the liquid ejecting apparatus are described, however, the invention is widely intended for a general liquid ejecting head and liquid ejecting apparatus. Of course, the invention can be applied to a liquid ejecting head or a liquid ejecting apparatus which ejects liquid other than the ink. The invention may be applied to a liquid ejecting apparatus including other liquid ejecting heads. The other liquid ejecting heads may include for example, various recording heads used in an image recording apparatus such as a printer, a color material ejecting head used in manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used in electrode formation of an organic EL display, a FED (an electric field emission display) or the like, a bioorganic matter ejecting head used in manufacturing bio-chips, or the like.

The entire disclosure of Japanese Patent Application Nos. 2011-286919 and 2011-286918, filed Dec. 27, 2011 are incorporated by reference herein.