Patent Description:
An inkjet image forming apparatus that discharges ink onto a sheet of paper or the like so as to form an image is known as a liquid discharge apparatus to discharge liquid.

Such inkjet image forming apparatus is provided with a liquid discharge head including a nozzle to discharge ink. Ink is discharged from the nozzle onto the sheet, which has been conveyed to a position where the sheet faces the liquid discharge head, so as to form an image on the sheet. If the sheet comes into contact with the nozzle during the formation of an image, the nozzle may be damaged, leading to an unstable discharge of ink. For this reason, some inkjet image forming apparatus includes a nozzle protector to protect the nozzle.

The nozzle protector is so bonded not only to a peripheral portion of a nozzle plate that the nozzle is provided on but a bonding member such as a frame member as not to peel off or fall off even if the sheet comes into contact with the nozzle protector. In Patent Literature <NUM> (<CIT>), for instance, the configuration, in which a recess is provided over the entire periphery of the bonding member (channel plate) and filled with an adhesive so as to bond the nozzle protector, is disclosed as a configuration for the bonding of the nozzle protector.

The adhesive to bond the nozzle protector prevents the nozzle protector from peeling off, and besides, serves as a sealing member to seal a space between the nozzle protector and the bonding member so that any foreign bodies including ink may not break in through the space. In the above configuration described in Patent Literature <NUM>, the recess to be filled with the adhesive is provided over the entire periphery of the bonding member, so that sealing is hard to achieve with the adhesive. To be specific: It is necessary for the sealing of a space between the nozzle protector and the bonding member with the adhesive to fill up the recess with the adhesive and, if an adhesive with a high viscosity is used in particular, air bubbles may get mixed in or a gap may be generated in the course of filling with the adhesive, so that it is difficult to fill the recess with the adhesive completely. Consequently, as the recess to be filled with the adhesive is larger in number, the possibility that a portion not filled with the adhesive is produced in the recess is increased and the sealing is made harder.

A liquid discharge head according to the invention is defined in the claims.

According to the embodiments of the invention, the recesses can improve sealing performance while ensuring bonding force between the nozzle protector and the channel substrate.

The invention is defined by the scope of the appended claims.

In the following, embodiments of the present disclosure are described based on the accompanying drawings. In different drawings for describing the embodiments of the present disclosure, components, such as constituent members and constituent parts, that have the same function or shape are given the same reference sign and no more described after once described as long as the components are recognizable as the same in function or shape.

First of all, based on <FIG> and <FIG>, a configuration of an inkjet image forming apparatus as an embodiment of a liquid discharge apparatus according to the present disclosure is described. <FIG> is a diagram illustrating a general arrangement of the inkjet image forming apparatus, and <FIG> is a diagram illustrating a control system of the inkjet image forming apparatus.

As illustrated in <FIG>, an image forming apparatus <NUM> (liquid discharge apparatus) according to the present embodiment includes a sheet feeding section <NUM> that feeds a sheet S for image formation, an image forming section <NUM> that forms an image on the sheet S, a conveyance section <NUM> that conveys the sheet S to the image forming section <NUM>, a drying section <NUM> that dries the sheet S, and a sheet recovering section <NUM> that recovers the sheet S with an image formed on the sheet S. The image forming apparatus <NUM> according to the present embodiment also includes a control section <NUM> (see <FIG>) for controlling the sheet feeding section <NUM>, the image forming section <NUM>, the conveyance section <NUM>, the drying section <NUM>, and the sheet recovering section <NUM>.

The sheet feeding section <NUM> includes a feed roller <NUM> that the sheet S as a lengthened sheet is wound on in a roll form, and a tension adjustment mechanism <NUM> that adjusts tension applied to the sheet S. The feed roller <NUM> is rotatable in a direction indicated with an arrow in <FIG>, and the sheet S is sent out by the rotation of the feed roller <NUM>. The tension adjustment mechanism <NUM> includes a plurality of rollers that the sheet S is stretched over so as to apply tension to the sheet S. Such rollers are partially moved to adjust the tension on the sheet S, so that the sheet S is sent out from the feed roller <NUM> under a constant tension.

The image forming section <NUM> includes a head unit <NUM> as a liquid discharge unit to discharge a liquid ink onto the sheet S, and a platen <NUM> as a sheet supporting member to support the sheet S conveyed. The head unit <NUM> includes a plurality of liquid discharge heads. Based on image data generated by the control section <NUM>, ink is discharged from the liquid discharge heads onto the sheet S so as to form an image on the sheet S. The ink to be discharged is liquid containing a coloring material, a solvent, and particles of a crystallizable resin dispersed in the solvent. The crystallizable resin refers to a resin that undergoes phase change, that is to say, is melted from a crystalline state into liquid if heated to a specified melting point or a higher temperature. The platen <NUM> is so arranged as to face the head unit <NUM> and supports a lower face of the sheet S as fed from the sheet feeding section <NUM>. The platen <NUM> is movable close to and away from the head unit <NUM> so as to keep the distance between the head unit <NUM> and the sheet S constant.

The conveyance section <NUM> includes a plurality of conveyance rollers <NUM>. The sheet S is stretched over the conveyance rollers <NUM> and as such conveyed to the image forming section <NUM> by the rotation of each conveyance roller <NUM>. The conveyance section <NUM> may include another conveyance means such as a conveyance belt.

The drying section <NUM> includes a heating drum <NUM> that heats the sheet S in order to promote the drying of the ink on the sheet S. The heating drum <NUM> is a cylindrical member rotating as the sheet S is wound onto an outer peripheral face of the cylindrical member, and a heat source such as a halogen heater is arranged inside the heating drum <NUM>. Instead of a contact heating means such as the heating drum <NUM>, a noncontact heating means such as a warm air generator that causes warm air to blow the sheet S may be used as a heating means for heating the sheet S.

The sheet recovering section <NUM> includes a recovery roller <NUM> that winds up and recovers the sheet S, and a tension adjustment mechanism <NUM> that adjusts tension applied to the sheet S. The recovery roller <NUM> is rotatable in a direction indicated with an arrow in <FIG>, and the sheet S is wound up in a roll form and thus recovered by the rotation of the recovery roller <NUM>. Similarly to the tension adjustment mechanism <NUM> of the sheet feeding section <NUM>, the tension adjustment mechanism <NUM> includes a plurality of rollers. The rollers are partially moved to adjust the tension on the sheet S, so that the sheet S is wound up by the recovery roller <NUM> under a constant tension.

The control section <NUM> includes an information processing unit such as a personal computer (PC). The control section <NUM> generates image data on an image to be formed on the sheet S, and controls various operations of the sheet feeding section <NUM>, the image forming section <NUM>, the conveyance section <NUM>, the drying section <NUM>, and the sheet recovering section <NUM>. For instance, the control section <NUM> controls the rotational speed of the feed roller <NUM>, the recovery roller <NUM>, and the conveyance rollers <NUM>, the temperature of the heat source for heating the heating drum <NUM>, and the like.

Next, an exemplary configuration of each liquid discharge head is described based on <FIG> and <FIG>.

<FIG> is an exploded perspective view of a liquid discharge head. <FIG> is a cross-sectional view in a transverse direction (direction indicated with an arrow Y in <FIG>) of the liquid discharge head illustrated in <FIG>.

As illustrated in <FIG>, a liquid discharge head <NUM> includes a plurality of head bodies <NUM>, a base member <NUM>, a cover <NUM>, a heat releasing member <NUM>, a manifold <NUM>, a printed circuit board <NUM> (PCB), and a module case <NUM>.

The head bodies <NUM> are held by the base member <NUM> as a holding member. In order to fit the head bodies <NUM> to the base member <NUM>, the head bodies <NUM> are each initially inserted into an opening 22c (see <FIG>) provided on the base member <NUM>. Then, the head bodies <NUM> are bonded to the cover <NUM> as bonded to the base member <NUM>. In the cover <NUM>, holes 23a (see <FIG>) corresponding to the head bodies <NUM>, respectively, are formed, and peripheral portions of the head bodies <NUM> are bonded to edges of the holes 23a. Finally, the head bodies <NUM> are screwed to the base member <NUM> and thus secured to the base member <NUM>. Specifically, flange parts of a common channel member <NUM> (see <FIG>) are provided on front and back sides in a longitudinal direction (direction orthogonal to the drawing plane of <FIG>) of each head body <NUM>, and such flange parts are screwed to the base member <NUM>. As a result, the common channel member <NUM> is held by the base member <NUM> and the relevant head body <NUM> is secured. The fitting structure of the head bodies <NUM> and the base member <NUM> is not limited to the above structure. The head bodies <NUM> may be fitted by bonding with an adhesive or by caulking.

As illustrated in <FIG>, the head body <NUM> includes a nozzle plate <NUM> with a nozzle <NUM> provided on the nozzle plate <NUM>, a channel substrate <NUM> where an individual liquid chamber <NUM> leading to the nozzle <NUM>, and the like are formed, a diaphragm <NUM> including a piezoelectric element <NUM>, a holding board <NUM> layered on the diaphragm <NUM>, and the common channel member <NUM> as a frame member layered on the holding board <NUM>. The cover <NUM> serves as a nozzle protector to protect a nozzle <NUM> in a nozzle plate <NUM>.

In the channel substrate <NUM>, not only the individual liquid chamber <NUM> but a supply side individual channel <NUM> leading to the individual liquid chamber <NUM> and a collection side individual channel <NUM> leading to the individual liquid chamber <NUM> are formed. In the holding board <NUM>, a supply side intermediate individual channel <NUM> leading to the supply side individual channel <NUM> through an opening 33a of the diaphragm <NUM> and a collection side intermediate individual channel <NUM> leading to the collection side individual channel <NUM> through an opening 33b of the diaphragm <NUM> are formed.

In the common channel member <NUM> (frame member), a supply side common channel <NUM> leading to the supply side intermediate individual channel <NUM> and a collection side common channel <NUM> leading to the collection side intermediate individual channel <NUM> are formed. The supply side common channel <NUM> leads to a supply port <NUM> through a channel <NUM> of the manifold <NUM>. The collection side common channel <NUM> leads to a collection port <NUM> through another channel <NUM> of the manifold <NUM>.

The printed circuit board <NUM> and the piezoelectric element <NUM> of the head body <NUM> are connected to each other through a flexible wiring member <NUM>. On the flexible wiring member <NUM>, a driver integrated circuit <NUM> (driver IC) is mounted.

The base member <NUM> is preferably made of a material with a low coefficient of linear expansion. Examples of the material with a low coefficient of linear expansion include <NUM> Alloy and an Invar material (FeNi36) each obtained by adding nickel to iron. If the base member <NUM> is made of such material, the amount of expansion of the base member <NUM> is small even if the temperature of the base member <NUM> rises due to the heat generation of the liquid discharge head <NUM>, so that the nozzle <NUM> is hardly displaced and the discharge of ink is prevented from getting out of position. If the nozzle plate <NUM> and the diaphragm <NUM> are each formed of a silicon single crystal substrate and made to have a coefficient of linear expansion substantially equal to the coefficient of linear expansion of the base member <NUM>, the displacement of the nozzle <NUM> due to thermal expansion is reduced still further.

<FIG> is a plan view illustrating an exemplary configuration of the head unit <NUM>.

In the example illustrated in <FIG>, the head unit <NUM> includes two liquid discharge heads <NUM>. Each liquid discharge head <NUM> is arranged so that a transverse direction (direction indicated with an arrow Y in the figure) of the relevant liquid discharge head <NUM> may agree with a sheet conveyance direction A and a longitudinal direction (direction indicated with an arrow X in the figure) of the relevant liquid discharge head <NUM> may agree with a direction orthogonal to the sheet conveyance direction A. As illustrated in <FIG>, the longitudinal direction of the liquid discharge head <NUM> refers to the longitudinal direction (direction indicated with the arrow X) of the liquid discharge head <NUM>, which extends in one direction as viewed from a direction orthogonal to a nozzle face 31a where the nozzle <NUM> (see <FIG>) is exposed. The transverse direction of the liquid discharge head <NUM> refers to a direction (indicated with the arrow Y) orthogonal to the longitudinal direction of the liquid discharge head <NUM> as viewed from the direction orthogonal to the nozzle face 31a. In the following description, the longitudinal direction and the transverse direction of the liquid discharge head <NUM> bare the same meanings as the above.

The head unit <NUM> illustrated in <FIG> is a so-called line head unit. When the sheet S is conveyed to a position where the sheet S faces the head unit <NUM>, ink is discharged from the nozzle <NUM> of each head body <NUM> without moving the head unit <NUM> with respect to the sheet S conveyed, so as to form an image on the sheet S.

Besides such line head unit, a so-called serial head unit that discharges ink while moving a liquid discharge head in a main scanning direction (sheet width direction) is usable as the head unit <NUM>.

<FIG> is a diagram illustrating an exemplary configuration of a serial head unit <NUM>. As illustrated in <FIG>, the serial head unit <NUM> includes a carriage <NUM> where a liquid discharge head <NUM> is mounted, a guide <NUM> (guide rod) for guiding the carriage <NUM> in a main scanning direction, namely, a sheet width direction B, and a drive unit <NUM> that moves the carriage <NUM>.

The drive unit <NUM> includes, for instance, a motor <NUM> as a driving source and a timing belt <NUM> put over a driving pulley <NUM> and a driven pulley <NUM>. If the driving pulley <NUM> is driven to rotate by the motor <NUM>, the timing belt <NUM> circles so as to move the carriage <NUM> along the guide <NUM> in the main scanning direction. The direction of rotation of the motor <NUM> is changed from one direction to the counter direction so as to subject the carriage <NUM> to the reciprocation in the main scanning direction.

In the serial head unit <NUM> as above, the carriage <NUM> is moved in the main scanning direction and, at the same time, ink is discharged from the liquid discharge head <NUM> according to an image signal, so as to form an image for one line on the sheet S being stopped. The sheet S is moved a specified amount at a time in a direction indicated with an arrow A in <FIG>, and the reciprocation of the carriage <NUM> and the discharge of ink are repeated so as to sequentially form images on the sheet S.

The temperature of a head unit (liquid discharge head) may greatly change depending on a thermal environment during the transport of products, for instance. If members included in the head unit are expanded or contracted attending the temperature change of the head unit, the difference in coefficient of linear expansion between the members causes strain to arise at and load to be put on a bonding spot between the members.

In particular, a large load is put on the cover <NUM>, so that the cover <NUM> will peel off if a bonding spot of the cover <NUM> cannot endure such load. If the cover <NUM> peels off and a foreign body such as ink happens to break into the head body <NUM> through the spot of peeling off of the cover <NUM>, a breakdown or a malfunction is caused by the foreign body.

If ink breaks in through the spot of peeling off of the cover <NUM> and adheres to a conductive part such as the flexible wiring member <NUM> (see <FIG>) in the head body <NUM>, for instance, a breakdown due to an electric leakage may be caused.

If the breaking-in ink adheres to the piezoelectric element <NUM> (see <FIG>) in the head body <NUM>, the ink, which solidifies afterward, prevents a suitable driving of the piezoelectric element <NUM>, which may lead to a poor discharge of ink.

Thus, the peeling off of the cover <NUM> causes various disadvantages including malfunctions and breakdowns. For this reason, in the embodiments of the present disclosure, the configurations as described below are adopted.

<FIG> is a plan view illustrating a state where a cover of a liquid discharge head according to a first embodiment of the present disclosure has been removed, <FIG> is a cross-sectional view taken along a line I-I in <FIG>, and <FIG> is a cross-sectional view taken along a line II-II in <FIG>. The liquid discharge head according to the present embodiment is substantially the same in basic structure as the liquid discharge head illustrated in <FIG> and <FIG>, so that the description on the parts as already described is appropriately omitted.

As illustrated in <FIG>, a liquid discharge head <NUM> according to the present embodiment includes the nozzle plate <NUM> with the nozzle <NUM> (see <FIG>) provided on the nozzle plate <NUM>, the cover <NUM> as a nozzle protector, which protects the nozzle <NUM>, the channel substrate <NUM> as a channel forming member, in which the supply side individual channel <NUM> (see <FIG>), the collection side individual channel <NUM> (see <FIG>), and the like are formed, the common channel member <NUM> as a frame member, and the base member <NUM> as a holding member, which holds the common channel member <NUM> and the like.

In <FIG>, an arrow X indicates a longitudinal direction of the liquid discharge head <NUM>, and an arrow Y indicates a transverse direction of the liquid discharge head <NUM>. In <FIG>, an arrow Z indicates a liquid discharge direction where liquid (ink) is discharged from the nozzle <NUM> of the nozzle plate <NUM>. In other words, in <FIG>, the nozzle face 31a of the nozzle plate <NUM>, at which the nozzle <NUM> is exposed, is directed upward.

The cover <NUM> covers at least a portion of the nozzle face 31a other than a portion where the nozzle <NUM> is arranged. In the present embodiment, the cover <NUM> covers an edge portion of the nozzle face 31a and the vicinity of the edge portion.

When a center side (the right side in <FIG>) of the nozzle face 31a is assumed as the inside and the side (the left side in <FIG>) opposite to the center side is assumed as the outside, a portion on the outside of the cover <NUM> is bonded to the base member <NUM> through an adhesive <NUM>, as illustrated in <FIG>. The base member <NUM> is arranged around the nozzle plate <NUM>, the channel substrate <NUM>, and the common channel member <NUM>, and the portion on the outside of the cover <NUM> is bonded to a face <NUM> of the base member <NUM> that is directed in a liquid discharge direction Z.

On the other hand, a portion on the inside of the cover <NUM> is bonded to the nozzle plate <NUM> and the channel substrate <NUM> through an adhesive <NUM>. The channel substrate <NUM> is arranged on a face opposite with the nozzle face 31a of the nozzle plate <NUM> (a lower face of the nozzle plate <NUM> in <FIG>), and a portion of the channel substrate <NUM> protrudes from an edge portion of the nozzle plate <NUM> toward the outside. The cover <NUM> is bonded to the portion of the channel substrate <NUM> protruding toward the outside and the periphery of the edge portion of the nozzle plate <NUM>.

The portions on the inside and the outside of the cover <NUM> are bonded to the different members through the adhesives <NUM> and <NUM>, respectively, and a space between the different members on one hand and the cover <NUM> on the other is sealed with the adhesives <NUM> and <NUM>, so that any foreign bodies including ink are prevented from breaking in through the space. If, however, various members in the liquid discharge head <NUM> are expanded or contracted attending the temperature change, load is put on the bonding spot of the cover <NUM> and the cover <NUM> may peel off, as described above.

In order to cope with such disadvantage, in the present embodiment, a plurality of recesses <NUM> are provided on the channel substrate <NUM> as a bonding member, to which the cover <NUM> is bonded, as illustrated in <FIG>.

Each recess <NUM> is provided in a bonding part <NUM> to be bonded to the cover <NUM> (the portion protruding from the nozzle plate <NUM> toward the outside) of the channel substrate <NUM>.

As illustrated in <FIG>, the recess <NUM> in the present embodiment is formed in the shape of a cube or rectangular parallelepiped having a bottom face 80a and four side faces 80b through 80e orthogonal to the bottom face 80a, and opens in the liquid discharge direction Z. The "orthogonal" includes at least one of the side faces 80b through 80e slightly tilted with respect to the plane orthogonal (vertical) to the bottom face 80a.

The bonding part <NUM> of the channel substrate <NUM> is a flat bonding part <NUM> (bonding face) except for a portion with the recess <NUM>.

In the present embodiment, the recesses <NUM> are provided in the bonding part <NUM> of the channel substrate <NUM>, so that the adhesive <NUM> applied to the bonding part <NUM> of the channel substrate <NUM> comes into the recesses <NUM> and the recesses <NUM> are filled with the adhesive <NUM>, as illustrated in <FIG>. The adhesive <NUM> is applied not only to the portion with the recess <NUM> but other portions (the flat bonding part <NUM>) of the channel substrate <NUM>, and the adhesives <NUM> and <NUM> are applied to bonding part <NUM> of the base member <NUM> and the nozzle plate <NUM>, respectively. Then, the cover <NUM> is pressed onto the adhesives <NUM> and <NUM> before the adhesives <NUM> and <NUM> are cured so as to bond the cover <NUM> to the different members (the channel substrate <NUM>, the nozzle plate <NUM>, and the base member <NUM>).

At a spot where the recess <NUM> is provided, in particular, the adhesive <NUM> is cured in the recess <NUM> so as to achieve an anchoring effect. In other words, the adhesive <NUM> is cured in the state of coming in the recess <NUM>, so that the bonding force is increased as compared with the case where flat faces are bonded to each other. Consequently, in the present embodiment, the bonding force between the cover <NUM> and the channel substrate <NUM> is improved and the cover <NUM> is less liable to peel off as compared with a configuration where no recesses are provided in a bonding part <NUM>.

In order to confirm the improvement of the bonding force owing to the above anchoring effect, a bonding force evaluation test was performed on the configuration according to the present embodiment and a configuration of a comparative example illustrated in <FIG>.

The comparative example is the same in configuration as the present embodiment except that the recess <NUM> is not provided in the bonding part <NUM> of the channel substrate <NUM>. The respective liquid discharge heads according to the comparative example and the present embodiment were each subjected to the temperature change in the range of <NUM> to <NUM>, and such temperature change cycle was performed ten times so as to check whether the cover <NUM> peeled off.

As a result, in half the comparative example specimens, the cover <NUM> peeled off. In the rest of the comparative example specimens, the cover <NUM> did not peel off indeed, but a bonded state of the cover <NUM> was barely maintained. In contrast, the cover <NUM> peeled off in none of the present embodiment specimens. It has thus been confirmed that the peeling off of the cover <NUM> is effectively suppressed according to the configuration of the present embodiment.

In the present embodiment, the adhesive <NUM> is applied over the entire periphery (the whole bonding part <NUM>) of the channel substrate <NUM>, while the recesses <NUM> are only provided in a portion 81Y of the bonding part <NUM> of the channel substrate <NUM> that extends in the transverse direction of the liquid discharge head <NUM> (see <FIG>). The recesses <NUM> are provided not over the whole bonding part <NUM> but only in the portion 81Y extending in the transverse direction because a large load is put on the portion 81Y in particular.

A test for checking the stress change attendant upon the temperature change was performed in advance on a liquid discharge head formed in a longitudinal shape, as is the case with the present embodiment. As a result, it has been found that a large load occurs especially in a portion extending in a transverse direction of the liquid discharge head. It is estimated from the above that, of the bonding part <NUM> extending over the entire periphery of the channel substrate <NUM>, the portion 81Y extending in the transverse direction, in particular, is a portion where the cover <NUM> is liable to peel off. Therefore, in the present embodiment, the recesses <NUM> are provided in the portion 81Y extending in the transverse direction of the bonding part <NUM> of the channel substrate <NUM>, which is a portion where the cover <NUM> is especially liable to peel off. Such configuration allows the bonding force in the portion 81Y extending in the transverse direction to be improved by the anchoring effect of the adhesive <NUM> filled into the recesses <NUM>, so that the peeling off of the cover <NUM> is effectively suppressed.

In a portion 81X of the bonding part <NUM> of the channel substrate <NUM> that extends in the longitudinal direction of the liquid discharge head <NUM>, the recesses <NUM> are not provided (see <FIG>). In other words, the portion 81X extending in the longitudinal direction gives a flat bonding face without the recesses <NUM> overall. The recesses <NUM> are not provided in the portion 81X extending in the longitudinal direction of the bonding part <NUM> of the channel substrate <NUM> in order to improve the sealing performance with an adhesive.

Generally speaking, a bonding part <NUM> with a recess is liable to cause air bubbles to get mixed in or a gap to be generated during the application of an adhesive, as compared with a flat bonding part <NUM> (bonding face). On the other hand, in such a configuration as the configuration of the present embodiment, in which the cover <NUM> is bonded to the channel substrate <NUM>, an adhesive needs to be applied thick so as to reduce a pressurizing force exerted on the channel substrate <NUM> during the bonding of the cover <NUM> so that the channel substrate <NUM> may not be damaged by the pressurizing force.

In the present embodiment, it is thus desirable to use an adhesive with a somewhat high viscosity, but the adhesive with a high viscosity is even harder to fill into the recess <NUM>, which increases the possibility that air bubbles or a gap is generated. Certain adhesives are less liable to generate air bubbles or a gap indeed, but such adhesives are limited in variety, so that the range of adhesive selection is inevitably restricted if any such adhesive is to be used.

While the recess <NUM> is hard to fill with an adhesive and an adhesive with a high viscosity in particular increases the possibility that air bubbles or a gap is generated, a portion where the recess <NUM> is to be provided is limited to the portion 81Y extending in the transverse direction of the bonding part <NUM> as described above, so as to reduce the possibility that air bubbles or a gap is generated. In other words, the recess <NUM>, in which air bubbles or a gap is liable to be generated, is limitedly provided in a desirable minimum region, so that air bubbles or a gap is less liable to be generated between bonding parts <NUM>, which improves the sealing performance.

According to the present embodiment, the sealing performance is ensured between the cover <NUM> and the channel substrate <NUM> even if an adhesive less liable to generate air bubbles or a gap in the recess <NUM> is not selected as an adhesive for bonding the cover <NUM> and the channel substrate <NUM> together. Consequently, the range of adhesive selection is widened, and the disadvantage of restricting the range of adhesive selection is ameliorated. In addition, if the recesses <NUM> are limitedly provided as in the present embodiment, the amount of an adhesive required to fill up the recesses <NUM> is small and, accordingly, cost reduction is expected as compared with the case where the recesses <NUM> are provided over the whole bonding part <NUM>.

According to the present embodiment, the recesses <NUM> are provided exclusively in the portion 81Y extending in the transverse direction, on which a large load is put in particular, so that an improved bonding force and an ensured sealing performance are both achieved. Consequently, the break in of foreign bodies into the liquid discharge head <NUM> is effectively suppressed and the possibility of malfunction and breakdown of the liquid discharge head <NUM> is reduced, leading to an improved reliability. The recesses <NUM> may be provided not only in the portion 81Y extending in the transverse direction but along part of the portion 81X extending in the longitudinal direction, as long as the recesses <NUM> are not provided over the entire periphery of the channel substrate <NUM>. Even in that case, the sealing performance is improved as compared with the case where the recesses <NUM> are provided over the entire periphery of the channel substrate <NUM>.

While the recesses <NUM> can be provided over the whole portion 81Y extending in the transverse direction, it is preferable for the improvement in sealing performance that the recesses <NUM> are provided in part of the portion 81Y extending in the transverse direction, as illustrated in <FIG>. The number of the recesses <NUM> provided for each portion 81Y extending in the transverse direction is not limited to two (see <FIG>) but may be one, three or larger. As viewed from the liquid discharge direction Z, the recesses <NUM> are rectangular in shape, while the recesses <NUM> may have a circular shape or another shape.

Next, embodiments each different from the embodiment (first embodiment) as above are described. The following description is chiefly made on parts different from the parts in the above embodiment, and description on the other parts, which are basically the same in configuration as the parts in the above embodiment, is omitted as appropriate.

<FIG> is a schematic cross-sectional view of a liquid discharge head according to a second embodiment of the present disclosure.

In the second embodiment illustrated in <FIG>, the base member <NUM> (see <FIG>) is not provided. The cover <NUM> in the present embodiment is bonded to the common channel member <NUM> (frame member) instead of the base member <NUM>. Specifically, the common channel member <NUM> has a peripheral wall part 35b that is arranged on the periphery (the outside) of the nozzle plate <NUM> and the channel substrate <NUM> and protrudes in the liquid discharge direction Z, and the cover <NUM> is bonded to a face <NUM> directed in the liquid discharge direction Z of the peripheral wall part 35b with an adhesive <NUM>. In the embodiment (first embodiment) illustrated in <FIG>, a portion upper in the figure of the base member <NUM> corresponds to a peripheral wall part 22b arranged on the periphery of the nozzle plate <NUM> and the channel substrate <NUM>.

The second embodiment is different from the above embodiment in that the base member <NUM> is not provided and the cover <NUM> is bonded to the peripheral wall part 35b of the common channel member <NUM>, and in such configuration also, the cover <NUM> may peel off if the different members are expanded or contracted attending the temperature change of the liquid discharge head <NUM>.

Therefore, in the present embodiment, similarly to the above embodiment, the recesses <NUM> are only provided in the portion 81Y (see <FIG>) extending in the transverse direction of the liquid discharge head <NUM> of the bonding part <NUM> of the channel substrate <NUM>, to which the cover <NUM> is bonded. As a result, similarly to the above embodiment, an improved bonding force and an ensured sealing performance are both achieved and the break in of foreign bodies into the liquid discharge head <NUM> is effectively suppressed, so that the reliability is improved.

<FIG> is a schematic cross-sectional view of a liquid discharge head according to a third embodiment of the present disclosure.

In the third embodiment illustrated in <FIG>, the recess <NUM> opens at an end face <NUM> directed to the outside (side opposite to a nozzle face center side) of the channel substrate <NUM>. In other words, the recess <NUM> in the present embodiment does not have the side face 80b (see <FIG>) of the recess <NUM> in the above first embodiment, which is arranged on the outside.

In the third embodiment, the recess <NUM> opens toward the outside of the channel substrate <NUM>, so that air bubbles in the recess <NUM> are easily ejected toward the outside through an opening. Consequently, the recess <NUM> is ready to fill with the adhesive <NUM>, which improves the sealing performance with the adhesive <NUM> still further. The configuration of the present embodiment, in which the recess <NUM> opens toward the outside of the channel substrate <NUM>, is applicable not only to the liquid discharge head <NUM> including the base member <NUM>, such as illustrated in <FIG>, but the liquid discharge head <NUM> not including the base member <NUM> (see <FIG>).

<FIG> is a schematic cross-sectional view of a liquid discharge head according to a fourth embodiment of the present disclosure.

In the fourth embodiment illustrated in <FIG>, the configuration of the third embodiment illustrated in <FIG> is reproduced and, moreover, the recess <NUM> is enlarged toward the inside so that the recess <NUM> may partially extend on a side of the nozzle plate <NUM> opposite to the nozzle face 31a side (a lower side of the nozzle plate <NUM> in <FIG>). In other words, part of the recess <NUM> is so arranged as to overlap the nozzle plate <NUM>, as viewed from the direction orthogonal to the nozzle face 31a.

Thus, in the fourth embodiment, part of the recess <NUM> is so arranged as to overlap the nozzle plate <NUM>, so that the adhesive <NUM>, which is filled into the recess <NUM>, spreads on the side of the nozzle plate <NUM> opposite to the nozzle face 31a side so as to get under the nozzle plate <NUM>. The adhesive <NUM> is cured while staying under the nozzle plate <NUM>, which enhances the anchoring effect of the adhesive <NUM> still further, and further improves the bonding force between the cover <NUM> and the channel substrate <NUM>.

Consequently, in the present embodiment, the peeling off of the cover <NUM> is suppressed more effectively and the reliability is improved. On the other hand, such a configuration as illustrated in <FIG>, <FIG> where the recess <NUM> does not overlap the nozzle plate <NUM> is advantageous in that the recess <NUM> is formed in the channel substrate <NUM> even after the nozzle plate <NUM> is attached onto the channel substrate <NUM>.

The configuration of the present embodiment, in which part of the recess <NUM> overlaps the nozzle plate <NUM>, is applicable not only to the liquid discharge head <NUM> including the base member <NUM>, such as illustrated in <FIG>, but the liquid discharge head <NUM> not including the base member <NUM> (see <FIG>) and a configuration where the recess <NUM> does not open toward the outside (see <FIG> and <FIG>) as well.

<FIG> is a schematic cross-sectional view of a liquid discharge head according to a fifth embodiment of the present disclosure.

In the fifth embodiment illustrated in <FIG>, the configuration of the fourth embodiment illustrated in <FIG> is reproduced and, moreover, part of the recess <NUM> is formed as a temporary bonding recess <NUM>. The temporary bonding recess <NUM> is a recess to be filled with an adhesive <NUM> for temporarily bonding the nozzle plate <NUM> and the channel substrate <NUM> together. The recess <NUM> and the temporary bonding recess <NUM> are arranged so that one recess <NUM> and one temporary bonding recess <NUM> may be provided at each end of the portion 81Y extending in the transverse direction, for instance. The number and arrangement of the recess <NUM> and the temporary bonding recess <NUM>, however, are changeable as appropriate.

As described above, part of the recess <NUM> may be used as the temporary bonding recess <NUM>. In order to bond the cover <NUM> in the present embodiment, the temporary bonding recess <NUM> is initially filled with the adhesive <NUM> for temporary bonding so as to temporarily bonding the nozzle plate <NUM> and the channel substrate <NUM> to each other. The adhesive <NUM> for temporary bonding is preferably an ultraviolet curable adhesive that is easy to cure, for instance.

To the nozzle plate <NUM> and the channel substrate <NUM> (the recess <NUM>) as temporarily bonded together, the adhesive <NUM> for regular bonding is applied so as to bond the cover <NUM> to the nozzle plate <NUM> and the channel substrate <NUM>. The nozzle plate <NUM> and the channel substrate <NUM> are temporarily bonded to each other before the cover <NUM> is subjected to the regular bonding to the nozzle plate <NUM> and the channel substrate <NUM> as bonded together, which facilitates the positioning of such different members with respect to one another.

The configuration, in which part of the recess <NUM> is used as the temporary bonding recess <NUM>, is applicable not only to the liquid discharge head <NUM> including the base member <NUM>, such as illustrated in <FIG>, but the liquid discharge head <NUM> not including the base member <NUM> (see <FIG>) and the configuration where the recess <NUM> does not open toward the outside (see <FIG> and <FIG>) as well.

The embodiments of the present disclosure have been described above, while the present disclosure is not limited to the above embodiments, and any appropriate design variations are possible without departing from the subject matter of the invention, within the scope of the appended claims.

In the present disclosure, the liquid discharge head refers to an operating part to discharge or inject liquid through a nozzle. The liquid to be discharged is not particularly limited as long as the liquid has a viscosity or surface tension allowing the discharge of the liquid from the liquid discharge head. Preferably, the liquid to be discharged has a viscosity of <NUM> mPa·s or less at normal temperature and pressure or after being heated or cooled.

Specific examples of the liquid include a solution, suspension, emulsion or the like containing a solvent such as water and an organic solvent, a colorant such as a dye and a pigment, a polymerizable compound, a resin, a functionality imparting material such as a surfactant, a biocompatible material such as a deoxyribonucleic acid (DNA), an amino acid or a protein, and calcium, or an edible material such as a natural coloring matter. Such liquid is used as, for instance, an inkjet ink, a surface treatment liquid, a liquid for the formation of a component or circuitry resist pattern of an electronic device or a light emitting device, or an ingredient liquid for three-dimensional modeling.

The liquid discharge head may include a plurality of head bodies, as is the case with the above embodiments, or include a single head body.

Examples of an energy source usable for the discharge of liquid include a piezoelectric actuator, such as a multilayer piezoelectric element and a thin-film piezoelectric element, a thermal actuator using a thermoelectric conversion element such as a heat generating resistor, and an electrostatic actuator including a diaphragm and a counter electrode.

In the present disclosure, the liquid discharge unit includes an operating part or a mechanism that is integrated with the liquid discharge head, that is to say, the liquid discharge unit includes an aggregate of parts related to the discharge of liquid.

Examples of the liquid discharge unit include a liquid discharge unit including at least one among a head tank, a carriage, a supply mechanism, a maintenance mechanism, a main scanning movement mechanism, and a liquid circulation device, as a combination with the liquid discharge head.

Examples of such integrated configuration include the configuration, in which the liquid discharge head and the operating part or the mechanism are secured to each other through fastening, bonding, engagement or the like, and the configuration, in which either of the liquid discharge head and the operating part or the mechanism is held movably with respect to the other.

Besides, the liquid discharge head and the operating part or the mechanism may be formed detachably from each other.

In an exemplary liquid discharge unit, a liquid discharge head and a head tank are integrated with each other.

In another exemplary liquid discharge unit, a liquid discharge head and a head tank are coupled to each other through a tube or the like so as to integrate the liquid discharge head and the head tank with each other. In such liquid discharge units, a unit including a filter may be added between the head tank and the liquid discharge head.

In another exemplary liquid discharge unit, a liquid discharge head and a carriage are integrated with each other.

In another exemplary liquid discharge unit, a liquid discharge head is movably held by a guide forming part of a scanning movement mechanism, so as to integrate the liquid discharge head and the scanning movement mechanism with each other.

In another exemplary liquid discharge unit, a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated with one another.

In another exemplary liquid discharge unit, a cap member forming part of a maintenance mechanism is secured to a carriage that a liquid discharge head is fitted to, so as to integrate the liquid discharge head, the carriage, and the maintenance mechanism with one another.

In another exemplary liquid discharge unit, a tube is coupled to a liquid discharge head that a head tank or a channel part is fitted to, so as to integrate the liquid discharge head and a supply mechanism with each other. Through the tube, liquid is fed from a liquid source retaining the liquid to the liquid discharge head.

The main scanning movement mechanism is assumed to include a single guide. The supply mechanism is assumed to include a single tube and a single charging part.

Examples of the liquid discharge apparatus include an apparatus that includes a liquid discharge head or a liquid discharge unit and drives the liquid discharge head so as to cause the liquid discharge head to discharge liquid.

In addition, examples of the liquid discharge apparatus include not only an apparatus to discharge liquid to an object where the liquid is adherable but an apparatus to discharge liquid into a gas or liquid.

The liquid discharge apparatus can include a means concerning the feed, conveyance or ejection of an object where liquid is adherable, a preprocessing device, a postprocessing device, and the like.

Thus, the liquid discharge apparatus is exemplified by an image forming apparatus to discharge ink so as to form an image on a sheet of paper, and a stereo-modeling apparatus (three-dimensional modeling apparatus) to discharge a modeling liquid to a powder bed obtained by forming powder into layered stuff, in order to produce a stereo-modeled product (three-dimensionally modeled product).

The liquid discharge apparatus is not limited to an apparatus that allows a meaningful image of a character, a figure or the like to be visualized with the liquid as discharged.

An exemplary liquid discharge apparatus may form a pattern that has no meaning in itself or a three-dimensional image.

The above-mentioned object where liquid is adherable refers to an object to be conveyed where liquid is adherable at least temporarily, with examples of such object including an object that the adhered liquid is firmly fixed to and an object that the adhered liquid permeates.

Specific examples include a sheet such as a sheet of paper, a recording paper, a recording sheet, a film, and a sheet of cloth, an electronic component such as an electronic board and a piezoelectric element, and such media as a powder bed (powder layer), an organ model, and a cell for examination, and any such objects are included unless the object where liquid is adherable is particularly limited.

The object where liquid is adherable may be made of such a material as paper, thread, fiber, cloth, leather, metal, plastics, glass, wood or ceramics, as long as liquid is adherable to the material even temporarily.

The sheet may be a lengthened continuous sheet such as a rolled paper or a sheet so cut in advance as to have a specified size such as a cut paper.

The present disclosure is also applicable to an apparatus that conveys an object to be conveyed other than the sheet.

The liquid discharge apparatus may be an apparatus that relatively moves a liquid discharge head and an object where liquid is adherable, to which apparatus the liquid discharge apparatus is not limited.

Specifically, the liquid discharge apparatus may also be a serial type apparatus (see <FIG>) that moves the liquid discharge head or a line type apparatus (see <FIG>) that does not move the liquid discharge head.

The liquid discharge apparatus is further exemplified by a treatment liquid application apparatus to discharge a treatment liquid to a sheet of paper in order to apply the treatment liquid onto a surface of the sheet for the purpose of surface modification of the sheet or other purpose, and a jet granulation apparatus to inject, through a nozzle, a composition liquid prepared by dispersing raw materials into a solution, so as to form particulates of the raw materials.

Claim 1:
A liquid discharge head (<NUM>) comprising:
a nozzle plate (<NUM>) having:
a nozzle (<NUM>) from which a liquid is to be discharged in a liquid discharge direction; and
a nozzle face having the nozzle, the nozzle face directed in the liquid discharge direction;
a nozzle protector (<NUM>) configured to cover a portion of the nozzle face other than the nozzle; and
a channel substrate (<NUM>) including:
a bonding part bonded to the nozzle protector (<NUM>) with an adhesive (<NUM>); and
a recess (<NUM>) in a transverse portion of the bonding part extending in a transverse direction of the liquid discharge head (<NUM>), the recess (<NUM>) filled with the adhesive (<NUM>), wherein the channel substrate (<NUM>) has the recess (<NUM>) in the transverse portion;
characterised in that
the channel substrate (<NUM>) does not have the recess (<NUM>) in a longitudinal portion of the bonding part (<NUM>) extending in a longitudinal direction orthogonal to the transverse direction of the liquid discharge head.