LIQUID EJECTION HEAD

A liquid ejection head includes a print element substrate having an ejection port forming member including an ejection surface on which a plurality of ejection port arrays for ejecting liquid are formed and a protection member having an opening corresponding to one of the ejection port arrays, the protection member is provided with at least one recessed portion at an end parallel to a direction of the plurality of ejection port arrays in a direction orthogonal to the plurality of ejection port arrays and a projection portion projecting in the direction orthogonal to the plurality of ejection port arrays, the projection portion is provided inside the at least one recessed portion, and the ejection port forming member has a corresponding recessed portion corresponding to the projection portion in the direction orthogonal to the plurality of ejection port arrays.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure relates to a liquid ejection head.

Description of the Related Art

A line type head in which a plurality of print element substrates are arrayed and which corresponds to the width of a print medium is used to perform continuous printing in one pass while conveying a plurality of print media continuously or intermittently. At that time, a problem may arise in that the print medium being conveyed floats up and contacts a print element substrate, thereby damaging a liquid ejection head. Japanese Patent Laid-Open No. 2006-334910 (referred to as Literature 1) and Japanese Patent Laid-Open No. H04-234665 (1992) (referred to as Literature 2) disclose that a protection member made of resin or metal is adhered to an ejection surface on which an ejection port is formed.

Incidentally, in the process of manufacturing a protection member, a plurality of protection members are connected and formed in one sheet, and one protection member is formed by separating this connection. This separation may cause the protection member to have a projection portion. In this case, there is a fear that in a protection member as that disclosed in Literatures 1 and 2, the projection portion of the protection member may be deformed toward an ejection surface side and the protection member may be attached in the state of floating up and peeled off in a case where a print medium contacts a print element substrate by floating up.

Thus, in view of the above problem, the present disclosure aims to provide a liquid ejection head that suppresses peeling due to floating up of a protection member.

SUMMARY OF THE INVENTION

A liquid ejection head according to the present disclosure is a liquid ejection head including a print element substrate having an ejection port forming member including an ejection surface on which a plurality of ejection port arrays for ejecting liquid are formed and a protection member having an opening corresponding to one of the ejection port arrays, wherein the protection member is provided with at least one recessed portion at an end parallel to the direction of the plurality of ejection port arrays in a direction orthogonal to the plurality of ejection port arrays and with a projection portion projecting in the direction orthogonal to the plurality of ejection port arrays, wherein the projection portion is provided inside the at least one recessed portion, and wherein the ejection port forming member has a corresponding recessed portion corresponding to the projection portion in the direction orthogonal to the plurality of ejection port arrays.

DESCRIPTION OF THE EMBODIMENTS

Examples of embodiments of the present disclosure will be described below with reference to the drawings. However, the following description does not limit the scope of the present disclosure. As an example, a thermal system in which a heating element generates air bubbles to eject liquid is used in the present embodiment. However, the present disclosure may also be applied to a liquid ejection head that uses a piezoelectric system or another one of the various other liquid ejection systems.

The present embodiment is an inkjet printing apparatus (printing apparatus) in which liquid such as ink is circulated between a tank and a liquid ejection head, but may be in another form. For example, the present embodiment may be in a form in which two tanks are provided on the upstream side and downstream side of the liquid ejection head to flow ink within a pressure chamber by flowing ink from one tank to the other tank instead of circulating the ink.

Further, the present embodiment is a so-called line type head having a length corresponding to the width of a print medium. However, the present disclosure is also applicable to a so-called serial type liquid ejection head that performs printing while scanning a print medium. Examples of the serial type liquid ejection head include one in which one print element substrate for black ink and one print element substrate for chromatic color ink are mounted. It should be noted that the liquid ejection head according to the present disclosure is not limited to this, and a short line head which is formed by arranging several print element substrates so as to cause ejection ports to overlap in an ejection port array direction may be formed, the short line head being shorter than the width of the print medium and being used to scan a print medium.

Description of the Basic Configuration of the Present Disclosure

Description of the Inkjet Printing Apparatus

FIG.1is a schematic configuration diagram of an apparatus for ejecting liquid according to the present disclosure, specifically, an inkjet printing apparatus1000(hereinafter also referred to as printing apparatus) that ejects ink to perform printing. The printing apparatus1000according to the present embodiment includes a conveying portion1that conveys a print medium2and a line-type liquid ejection head3arranged substantially orthogonal to a conveyance direction in which the print medium2is conveyed. The liquid ejection head3ejects cyan (C), magenta (M), yellow (Y), and black (Bk) inks, so that a color image can be printed on the print medium2. In the figure, an X direction is the conveyance direction of the print medium2, a Y direction is the width direction of the print medium, and a Z direction is a vertically upward direction.

The print medium2is mounted on the conveying portion1and is conveyed in the X direction at a predetermined speed below the four print heads3that eject different inks. InFIG.1, the four print heads3are arranged in the X direction in the order of cyan, magenta, yellow, and black, and ink is ejected onto the print medium2in this order. In each print head3, a plurality of ejection ports for ejecting ink are arrayed in the Y direction.

Although cut paper is shown as the print medium2inFIG.1, the print medium2may be continuous paper supplied from roll paper. Further, the print medium is not limited to paper, but may also be a film or the like.

FIG.2is a block diagram for explaining a control configuration in the printing apparatus1000. A control unit500is formed of a CPU and the like and controls the entire printing apparatus1000while using a RAM502as a work area in accordance with a program and various parameters stored in a ROM501. The control unit500performs predetermined image processing on image data received from a host device600connected to the outside in accordance with the program and parameters stored in the ROM501and generates ejection data that can be ejected by the print head3. The print head3is then driven in accordance with the ejection data to eject ink at a predetermined frequency.

During the ejection operation by the print head3, the control unit500drives a conveyance motor503to convey the print medium2in the X direction at a speed corresponding to a drive frequency. As a result, an image according to the image data received from the host device600is printed on the print medium. Information on a used area for the ejection ports used for ejection in the print head3is stored in the ROM501in a rewritable manner for each print head3. A method of setting the used area will be described in detail later.

Description of an Ink Circulation Path

FIG.3is a schematic diagram showing a circulation path applied to the printing apparatus according to the present embodiment and is a diagram in which the liquid ejection head3is fluidly connected to a first circulation pump1002, a buffer tank1003, and the like. AlthoughFIG.3shows only a path through which ink of one color of CMYK inks flows to simplify description, a circulation path compatible with a plurality of colors is actually provided in the liquid ejection head3and the printing apparatus1000. A buffer tank1003as a sub tank connected to a main tank1006includes an atmosphere communication port (not shown) that establishes communication between the inside and outside of the tank and can discharge air bubbles in ink to the outside. The buffer tank1003is also connected to a replenishment pump1005. In a case where liquid is consumed with the liquid ejection head3by ejecting (discharging) ink from the ejection ports of the liquid ejection head, such as printing by ejecting ink or suction recovery, the replenishment pump1005transfers the consumed ink from the main tank1006to the buffer tank1003.

The first circulation pump1002has a role in drawing out liquid from a liquid connection portion111of the liquid ejection head3and flowing the liquid to the buffer tank1003. As the first circulation pump1002, a displacement pump having a quantitative liquid feeding ability is preferable. Specific examples include a tube pump, gear pump, diaphragm pump, syringe pump, and the like. However, an embodiment in which a general constant flow valve or relief valve is arranged at a pump outlet to ensure a constant flow rate may also be used. While the liquid ejection head3is being driven, a certain amount of ink flows through a common collecting channel212by the first circulation pump1002. It is preferable to set this flow rate to a level or more at which a temperature difference between the print element substrates10in the liquid ejection head3does not affect print image quality. However, in a case where too a high flow rate is set, a negative pressure difference becomes too large between the print element substrates10due to the effect of pressure loss in a channel within the liquid ejection unit300, resulting in density unevenness in an image. Thus, it is preferable to set the flow rate in consideration of differences in temperature and negative pressure between the print element substrates10.

A negative pressure control unit230is provided in a path between a second circulation pump1004and the liquid ejection unit300. Thus, the negative pressure control unit230has the function of operating to maintain a pressure downstream of the negative pressure control unit230(on the liquid ejection unit300side) at a preset constant pressure even in a case where the flow rate of a circulation system fluctuates due to a difference in printing duty. As two pressure adjustment mechanisms that form the negative pressure control unit230, any mechanism that can control a pressure downstream of the mechanism itself within a certain range of fluctuations around a desired set pressure may also be used. As an example, a mechanism similar to a so-called “pressure-reducing regulator” can be used. In the case of using the pressure-reducing regulator, as shown inFIG.3, it is preferable that the second circulation pump1004pressurize the upstream side of the negative pressure control unit230via a liquid supply unit220. This can suppress the effect of a water head pressure of the buffer tank1003on the liquid ejection head3, so that the degree of freedom in the layout of the buffer tank1003in the printing apparatus1000can be increased. It is only required that the second circulation pump1004have a certain head pressure or more within the range of ink circulation flow rates used at the time of driving the liquid ejection head3, and a turbo type pump, a displacement pump, or the like can be used. Specifically, a diaphragm pump or the like is applicable. Further, instead of the second circulation pump1004, for example, a water head tank arranged with a certain water head difference with respect to the negative pressure control unit230is also applicable.

As shown inFIG.3, the negative pressure control unit230includes the two pressure adjustment mechanisms for which different control pressures are set. Of the two negative pressure adjustment mechanisms, one for which a relatively high pressure is set (denoted as H inFIG.3) and the other for which a relatively low pressure is set (denoted as L inFIG.3) are connected to a common supply channel211and a common collecting channel212in the liquid ejection unit300, respectively, through the liquid supply unit220. The liquid ejection unit300is provided with the common supply channel211, the common collecting channel212, and an individual supply channel213and individual collecting channel214that communicate with the respective print element substrates. Since the individual channel213communicates with the common supply channel211and the common collecting channel212, a portion of liquid flowed using the second circulation pump1004passes from the common supply channel211through a channel inside the print element substrate10and flows into the common collecting channel212(arrows inFIG.3). This is because a pressure difference is provided between the pressure adjustment mechanism H connected to the common supply channel211and the pressure adjustment mechanism L connected to the common collecting channel212, and the first circulation pump1002is connected only to the common collecting channel212.

As described above, in the liquid ejection unit300, the flow of liquid that passes through the common collecting channel212and a flow that passes through each print element substrate10from the common supply channel211to the common collecting channel212are produced. Thus, heat generated in each print element substrate10can be discharged to the outside of the print element substrate10by flowing from the common supply channel211to the common collecting channel212. In addition, such a configuration makes it possible to cause an ink flow even in an ejection port and a pressure chamber which are not used to perform printing while printing is being performed using the liquid ejection head3, so that thickening of ink at those sites can be suppressed. Further, thickened ink and foreign matter in ink can be discharged to the common collecting channel212. Therefore, the liquid ejection head3according to the present embodiment enables high-speed and high-quality printing.

Description of a Print Head

The configuration of the liquid ejection head3according to the present embodiment will be described.FIGS.4A and4Bare perspective views of the liquid ejection head3according to the present embodiment. The liquid ejection head3is a line type liquid ejection head in which 17 print element substrates10capable of ejecting ink are arrayed in a straight line (arranged inline). As shown inFIG.4A, the liquid ejection head3includes the print element substrates10and a signal input terminal91and a power supply terminal92electrically connected to each other via a flexible wiring substrate40and an electrical wiring substrate90. The signal input terminal91and the power supply terminal92are electrically connected to a control unit of the printing apparatus1000and supply an ejection drive signal and power necessary for ejection to each printing element substrate10, respectively. Gathering wiring using an electric circuit in the electrical wiring substrate90can reduce the number of signal output terminals91and the number of power supply terminals92as compared to the number of print element substrates10. As a result of this, it is possible to reduce the number of electric connection portions that need to be removed at the time of assembling the liquid ejection head3to the printing apparatus1000or replacing the liquid ejection head. As shown inFIG.4A, the liquid connection portion111provided on one side of the liquid ejection head3is connected to a liquid supply system in the printing apparatus1000. As a result, ink is supplied from the supply system in the printing apparatus1000to the liquid ejection head3, and ink that has passed through the liquid ejection head3is collected to the supply system in the printing apparatus1000. As described above, ink can be circulated through a path in the printing apparatus1000and a path in the liquid ejection head3.

Next, the configuration of the liquid ejection head3will be specifically described with reference toFIG.5.FIG.5shows an exploded perspective view of each component or unit that forms the liquid ejection head3. The liquid ejection unit300, the liquid supply unit220, and the electrical wiring substrate90are attached to a housing80. The liquid supply unit220is provided with a liquid connection portion111, and in the liquid supply unit220, there is provided a filter221(seeFIG.3) for each color communicating with an opening of the liquid connection portion111in order to remove foreign matter from supplied ink. Liquid that has passed through the filter221is supplied to the negative pressure control unit230arranged on the supply unit220so as to correspond to each color. The negative pressure control unit230is a unit including a pressure adjustment valve for each color. The negative pressure control unit230greatly attenuates a change in pressure loss in the supply system in the printing apparatus1000(the supply system on the upstream side of the liquid ejection head3) generated due to fluctuations in a liquid flow rate through the functions of a valve, spring member, and the like provided therein. As a result, the negative pressure control unit230can stabilize a negative pressure change on the downstream side (liquid ejection unit300side) of a pressure control unit within a certain range. As shown inFIG.3, the negative pressure control unit230for each color includes two pressure adjustment valves for each color, each of which is set at a different control pressure. Further, the negative pressure control unit230set at a high pressure communicates with the common supply channel211in the liquid ejection unit300and the negative pressure control unit230set at a low pressure communicates with the common collecting channel212, via the liquid supply unit220.

The housing80includes a liquid ejection unit support portion81and an electrical wiring substrate support portion82, supports the liquid ejection unit300and the electrical wiring substrate90, and ensures the rigidity of the liquid ejection head3. The electrical wiring substrate support portion82is for supporting the electrical wiring substrate90and is fixed to the liquid ejection unit support portion81with screws. The liquid ejection unit support portion81has a role in correcting warpage and deformation of the liquid ejection unit300to ensure the accuracy in relative positions of the plurality of print element substrates10, thereby suppressing streaks and unevenness in a printed subject. Further, the liquid ejection unit support portion81is provided with openings83and84into which a joint rubber100is inserted. Liquid supplied from the liquid supply unit220is guided via a liquid supply joint222and the joint rubber100to the second channel member60that forms the liquid ejection unit300.

Next, the configuration of the channel member210included in the liquid ejection unit300will be described. As shown inFIG.5, the channel member210is a stack of a first channel member50and a second channel member60, and a plurality of ejection modules200are bonded to the bonding surface of the first channel member50with an adhesive (not shown). As a result, the channel is configured such that liquid supplied from the liquid supply unit220is distributed to each ejection module200, and liquid circulating from the ejection module200returns to the liquid supply unit220. The channel member210is fixed to the liquid ejection unit support portion81with screws.

FIGS.6A to6Dare diagrams for explaining the detailed configuration of the channel member210.FIG.6Ashows the abutting surface of the support member30that abuts the print element substrate10, andFIG.6Bshows the abutting surface of the first channel member50that abuts the support member30.FIG.6Cshows a cross section of the middle layer of the first channel member, andFIG.6Dshows the surface of the second channel member on the liquid ejection unit support portion81side. It should be noted thatFIGS.6A to6Care views seen from an ejection surface, andFIG.6Dis a view seen from the liquid ejection unit support portion81side.

A plurality of the support members30are arranged in the first channel member50, and the print element substrate10is arranged in each support member30. Such a configuration makes it possible to assemble the print heads3of various sizes by adjusting the number of arrays with the ejection modules200. The first channel member50and the second channel member60are bonded in the order ofFIGS.6A to6C, and a surface opposite to the surface shown inFIG.6Cand a surface opposite to the surface shown inFIG.6Dare bonded to each other.

As shown inFIG.6A, on the surface of the support member30that abuts the print element substrate10, a support member communication port31is arranged so as to be in fluid communication with the print element substrate10and is formed in the individual supply channel213and the individual collecting channel214(seeFIG.3). The support member communication port31is in fluid communication with the common supply channel211or the common collecting channel212via a communication port51formed in the first channel member50.

As shown inFIG.6C, common channel grooves61and62extending in the X direction together with the common supply channel211and the common collecting channel212(seeFIG.3) are formed in the first channel member50. As a result, a set of the common supply channel211and the common collecting channel212is formed in the channel member210for each liquid color (seeFIGS.7A and7B).

As shown inFIG.6D, a common communication port63in fluid communication with the liquid supply unit220is formed at opposite ends or one end of the common channel grooves61and62. The communication port51is formed at the other end of an individual channel groove52of the first channel member50, and the first channel member50fluidly communicates with the plurality of ejection modules200via the communication port51. The individual channel groove52makes it possible to gather the channels at the center of the channel member.

Next, a channel structure in the channel member210will be described with reference toFIGS.7A and7B.FIG.7Ais an enlarged perspective view of a portion of a channel in the channel member210from the side of the first channel member50on which the ejection module200is mounted.FIG.7Bis a diagram showing a cross section taken along line VIIB-VIIB inFIG.7A.

The print element substrate10of the ejection module200is disposed on the communication port51of the first channel member50via the support member30. Although the communication port51corresponding to the common collecting channel212is not shown inFIG.7B, it is clear fromFIG.7Athat the communication port51is shown in another cross section.

As already described, the common supply channel211is connected to the first negative pressure control unit230set at a relatively high pressure, and the common collecting channel212is connected to the second negative pressure control unit230set at a relatively low pressure. There is formed an ink supply path that passes through the common communication port63(seeFIGS.6A to6D), the common supply channel211, and the support member communication port31and supplies ink to a channel formed in the print element substrate10. Similarly, there is formed an ink collecting path extending from the channel in the print element substrate10, and including the support member communication port31, the communication port51, the common collecting channel212, and the common communication port63(seeFIGS.7A and7B). While ink is circulated in this way, an ejection operation according to ejection data is performed in the print element substrate10, and ink that has not been consumed by the ejection operation among the ink supplied through the ink supply path is collected through the ink collecting path.

Description of the Ejection Module

FIG.8Ais a perspective view showing one ejection module200, andFIG.8Bis an exploded view of the ejection module200. As a method of manufacturing the ejection module200, first, the print element substrate10and the flexible wiring substrate40are adhered onto the support member30preprovided with the liquid support member communication port31. Thereafter, a terminal16on the print element substrate10and a terminal41on the flexible wiring substrate40are electrically connected by wire bonding, and a wire bonding portion (electric connection portion) is then covered and sealed with a sealing material. A terminal42on the flexible wiring substrate40opposite to the print element substrate10is electrically connected to a connection terminal93(seeFIG.5) on the electrical wiring substrate90. The support member30is a support body that supports the print element substrate10and is also a channel member that establishes fluid communication between the print element substrate10and the channel member210, and thus is preferably one which has a high flatness and can be sufficiently highly reliably bonded to a print element substrate. As a material for the support member30, for example, alumina or a resin material is preferable.

Description of the Print Element Substrate

The configuration of the print element substrate10according to the present embodiment will be described.FIG.9Ashows a plan view of the surface of the print element substrate10on which an ejection port13is formed,FIG.9Bshows an enlarged view of the portion denoted by IXB inFIG.9A, andFIG.9Cshows a plan view of a back surface opposite to the surface shown inFIG.9A. Here, the configuration of the print element substrate10in the present embodiment will be described. It should be noted that hereinafter, a direction in which an ejection port array in which a plurality of the ejection ports13are arrayed extends will be referred to as “ejection port array direction.”

As shown inFIG.9B, a print element15, which is a heating element (pressure generating element) to foam liquid using generated thermal energy, is arranged in a position corresponding to one of the ejection ports13. A pressure chamber23having the print element15therein is defined by a partition22. The print element15is electrically connected to the terminal16by electrical wiring (not shown) provided in the print element substrate10. The print element15then generates heat based on a pulse signal inputted from a control circuit in the printing apparatus1000via the electrical wiring substrate90(seeFIG.5) and the flexible wiring substrate40(seeFIGS.8A and8B) to boil liquid. The liquid is ejected from the ejection port13by a bubbling force generated by this boiling. As shown inFIG.9B, along each ejection port array, a liquid supply path18extends on one side, and a liquid collecting path19extends on the other side. The liquid supply path18and the liquid collecting path19are channels extending in the ejection port array direction provided in the print element substrate10and communicate with the ejection port13via a supply port17aand a collecting port17b, respectively.

As shown inFIG.9C, a sheet-like cover plate20is laminated on the back side opposite to the surface of the print element substrate10on which the ejection port13is formed, and the cover plate20is provided with a plurality of openings21communicating with the liquid supply path18and the liquid collecting channel19to be described later. In the present embodiment, the cover plate20is provided with four supply openings21afor one liquid supply path18and three collecting openings21bfor one liquid collecting path19. However, the number of openings is not limited to them. As shown inFIG.9B, each opening21of the cover plate20communicates with the communication port51shown inFIG.7A. The cover plate20preferably has sufficient corrosion resistance to liquid, and the shape and position of the opening21require high accuracy so that ink is supplied to the pressure chamber. Thus, it is preferable to use a photosensitive resin material or a silicon plate as a material for the cover plate20and provide the opening21by a photolithography process. The thickness of the cover plate is preferably about 30 to 600 μm from the viewpoint of strength and workability.

FIG.10is a perspective view showing a cross section of the print element substrate10and the cover plate20taken along line X-X inFIG.9A.FIG.10shows four ejection port arrays in an ejection port forming member12of the print element substrate10, but the present disclosure may include more or fewer ejection port arrays. Here, a liquid flow within the print element substrate10will be described. The cover plate20has a function as a lid that forms a portion of the walls of the liquid supply path18and the liquid collecting path19formed in a substrate11of the print element substrate10. In the print element substrate10, the substrate11made of Si and the like and the ejection port forming member12made of a photosensitive resin are laminated together, and the cover plate20is bonded to the back surface of the substrate11. The print element15is formed on one side of the substrate11(seeFIGS.9A to9C), and on the back side opposite to the one side, a groove forming the liquid supply path18and the liquid collecting path19extending along the ejection port arrays is formed. The liquid supply path18and the liquid collecting path19formed of the substrate11and the cover plate20are connected to the common supply channel211and the common collecting channel212in the channel member210, respectively, and a pressure difference is generated between the liquid supply path18and the liquid collecting path19. Due to this pressure difference, liquid in the liquid supply path18provided in the substrate11flows to the liquid collecting path19via the supply port17a, the pressure chamber23, and the collecting port17b(a flow indicated by an arrow C inFIG.10). This flow makes it possible to collect thickened ink, bubbles, foreign matter, and the like generated by evaporation from the ejection port13into the liquid collecting path19in the ejection port13and the pressure chamber23that are not in an ejection operation and suppress an increase in the viscosity of ink or in the concentration of a color material in the ejection port13and the pressure chamber23. The liquid collected into the liquid collecting path19passes through the opening21of the cover plate20and the support member communication port31of the support member30as shown inFIGS.7A and7B. The liquid to the liquid collecting path19is then collected through the support member communication port31of the support member30, the communication port51of the first channel member50, and the common collecting channel212in this order, and is collected into a supply path (FIG.3) in the printing apparatus1000.

Description of Embodiments of the Present Disclosure

First Embodiment

A first embodiment of the present disclosure will be described. Descriptions of functions and configurations similar to the basic configuration of the present disclosure will be omitted, and differences will be described.

FIG.11Ais a perspective view of a simplified ejection module according to the first embodiment.FIG.11Bis an exploded perspective view ofFIG.11A.FIG.11Cis a cross-sectional view taken along line XIC-XIC inFIG.11A.FIG.12is a schematic diagram showing an adhesive application state inFIG.11C. InFIGS.11A,11B,11C, and12, a portion of the configurations is simplified to facilitate understanding.

The present embodiment is different from the basic configuration in that a protection member140is laminated on the surface (ejection surface120) of the ejection port forming member12. Specifically, as shown inFIGS.11B and11C, an opening141corresponding to an ejection port array14is formed in the protection member140, and a recessed portion121is formed between the adjacent ejection port arrays14in the ejection surface120. The ejection surface120and the protection member140are adhered to each other with an adhesive150applied to the recessed portion121. With such a configuration, in a case where the print medium2floats up during conveyance, the protection member140plays a role in preventing contact between the print medium2and the print element substrate10, thereby reducing the risk of damage to the liquid ejection head3.

The print medium2may be an offset print sheet or the like, which may contain mineral particles such as silica and calcium carbonate in a coating layer. In the case of collision during conveyance, these particles fall off and rub against the ejection surface, so that the ejection surface is damaged. Since these minerals have an elastic modulus of a few tens of gigapascals (GPa) or more, it is preferable that the protection member also have an elastic modulus of 50 GPa or more, and as the material, a metal material such as stainless steel, titanium, and aluminum, silicon, or alumina can be suitably used. Further, it is preferable that the length of the opening141of the protection member140in a direction substantially intersecting the ejection port array direction be 250 μm or more and less than an interval between the adjacent ejection port arrays14, and the thickness of the protection member140be less than 50 μm. As a result, in a case where a cleaning mechanism (not shown) of the printing apparatus abuts the liquid ejection head3during maintenance at the time of printing, the cleaning mechanism (not shown) can more suitably collect liquid in the liquid ejection head3. Thus, it is preferable that the outer shape and opening141of the protection member140be worked with high accuracy, and as a working method, for example, etching, laser working, or press working can be suitably used.

As shown inFIG.12, the adhesive150is applied to the recessed portion121. Applying the adhesive to the recessed portion121can make an adhesive force stronger than the case of applying the adhesive to a flat portion in the ejection surface120. At this time, it is preferable that the ejection surface120have water repellency against liquid and the recessed portion121have non-water repellency. As a result, the adhesive150can easily remain in the recessed portion121, and the risk of the adhesive150flowing into the ejection port13can be reduced. As the adhesive150, for example, a thermosetting adhesive can be suitably used. Further, in order to further strengthen the force of adhesion between the ejection surface120and the protection member140, a method of forming a contact layer (not shown) on at least the ejection surface120side of the protection member140can also be suitably used.

FIG.13is a perspective view of a simplified print element substrate showing a modification ofFIG.11B.FIG.14Ais a perspective view of a simplified ejection module showing a modification ofFIG.11A.FIG.14Bis an enlarged view of the portion denoted by XIVB inFIG.14A.FIG.14Cis an enlarged view of the portion denoted by XIVC inFIG.14A. InFIGS.13,14A,14B, and14C, a portion of the configurations is simplified to facilitate understanding. As one modification of the first embodiment, as shown inFIG.13, the recessed portions121formed between the adjacent ejection port arrays14may be connected in a groove shape. Such a configuration makes it possible to make the force of adhesion between the ejection surface120and the protection member140stronger. Further, as another modification of the first embodiment, as shown inFIGS.14A,14B, and14C, an R shape143may be formed at the corners of the protection member140. With such a configuration, in a case where the cleaning mechanism (not shown) of the printing apparatus abuts the liquid ejection head3during maintenance at the time of printing, the risk of damage to the cleaning mechanism (not shown) due to the corners of the protection member140can be reduced. Further, in order to avoid alignment marks122aand122bused for positioning between the adjacent print element substrates10, openings142aand142bfor pattern avoidance can also be formed in the protection member140. In addition, a cut portion (not shown) can also be formed in the protection member140in accordance with a pattern on the printing element substrate, such as a print element substrate number (not shown) used to identify the printing element substrate10. At that time, forming an R shape in the cut portion (not shown) makes it possible to reduce the risk of damage to the cleaning mechanism (not shown).

Characteristics of the Protection Member of the Present Embodiment

The example of the protection member140described above is a brief description. The protection member140according to the present embodiment in which a recessed portion having a projection portion formed therein is formed will be described in detail with reference toFIGS.15A to18E.

FIG.15Ais a schematic diagram of a simplified ejection module.FIG.15Bis an enlarged view of the portion denoted by XVB inFIG.15A.FIG.15Cis a cross-sectional view taken along line XVC-XVC inFIG.15B.

In the process of manufacturing the protection member140, a plurality of protection members are formed in one sheet and are connected to each other via a connecting portion. For example, one protection member is provided by separating the connecting portion due to a vibration. At this time, in a case where the connecting portion is separated, a projection portion is formed in the protection member140in a direction orthogonal to the ejection port array14of the print element substrate10.

Thus, in a direction orthogonal to the ejection port array14of the print element substrate10, the protection member140according to the present embodiment is provided with at least one recessed portion144at an end parallel to the direction of the ejection port array14and a projection portion145that projects in a direction orthogonal to the ejection port array14of the print element substrate10. The projection portion145is provided inside the recessed portion144of the protection member140. As a result, the projection portion145is provided within a formation area where the protection member140is formed without projecting from the protection member140.

Further, as shown inFIG.15C, the ejection port forming member12is provided with a recessed portion12acorresponding to the projection portion145of the protection member140in a direction orthogonal to the ejection port array14of the print element substrate10and in a vertical direction. The recessed portion12aof the ejection port forming member12is formed to expose the substrate11located vertically in a lower position. The projecting projection portion145of the protection member140is accommodated in the recessed portion12aof the ejection port forming member12. As a result, the projection portion145is accommodated in the recessed portion12aand does not contact the ejection surface120, so that it is possible to suppress floating up of the protection member140.

The protection member140has a recessed portion144(first recessed portion) at an end parallel to the ejection port array direction in a direction orthogonal to the ejection port array14of the print element substrate10and may have a recessed portion147(second recessed portion) at the other end opposite to the end. The recessed portion144at the end and the recessed portion147at the other end are formed at the same position as the recessed portion12a. As a result, the recessed portion12ais provided to correspond to the projection portion145of the protection member140, can accommodate the projection portion145, and can suppress floating up of the protection member140.

FIG.16Ais a plan view of a plurality of protection members molded into one sheet of the liquid ejection head according to the present disclosure, andFIG.16Bis a partially enlarged view of the XVIB inFIG.16A.FIG.16Cis a partially enlarged view ofFIG.16Bin the state of being separated from the sheet due to a vibration.

The protection member140according to the present embodiment has a thickness of 50 μm or less in order to reduce cost, and a plurality of the protection members140are formed by etching a single large material sheet160to prevent burrs from being formed in the opening141or the like.

As shown inFIG.16B, the plurality of protection members140are connected via a connecting portion146and are separated from the connecting portion146by vibrating the sheet160. As a result, as shown inFIG.16C, the projection portion145is formed in a direction in which the protection member140is substantially orthogonal to the ejection port array direction. The shape of the connecting portion146may be tapered so as to become narrower toward the protection member140or may be tapered so as to become wider toward the protection member140. The shape of the connecting portion146is preferably tapered so as to become narrower toward the protection member140. However, preferably, it is only required that the width of a portion connected to the protection member140be shorter. This enables easy separation from the connecting portion146by generating a vibration. Further, in a case where the width of the portion connected to the protection member140is shorter, the recessed portion12aof the ejection port forming member12can be formed to have a small size.

However, although the protection member140can be produced at low cost by being vibrated and separated as described above, the inventors have discovered that the projection portion145may be twisted due to the vibration and may be deformed upward or downward with respect to the vertical direction.

FIGS.17A to17Care a schematic cross-sectional view showing a print element substrate as a comparative example different from that in the present embodiment, a cross-sectional view of the print element substrate according to the present disclosure, and a cross-sectional view showing a modification.

A case will be described where the projection portion145of the protection member140is deformed upward with respect to the vertical direction. Since there is a risk that the cleaning mechanism (not shown) of the printing apparatus1000abuts the projection portion145and is damaged during maintenance at the time of printing, it is desirable that the projection portion145be provided in a position where the projection portion145does not contact the cleaning mechanism.

In the present embodiment, a sealing portion110(seeFIG.15A), which is a portion connecting the substrate11and the flexible wiring substrate40, is located higher than the print element substrate10in the vertical direction, and the cleaning mechanism is driven in the ejection port array direction to avoid the sealing portion110and the like. The projection portion145is provided in the position denoted by XVB and F inFIG.15Aof a side parallel to the ejection port array in the protection member140by etching or the like during the manufacturing process so as not to contact the cleaning mechanism.

In a case where the projection portion145of the protection member140is deformed downward with respect to the vertical direction, in the comparative example, the projection portion145may interfere with the ejection surface120and the protection member140may deform and float up, as shown inFIG.17A. In a case where an area from an end of the protection member140to the opening141of the protection member140is large, floating up is suppressed due to the rigidity of the protection member140; in a case where the area from the end of the protection member140to the opening141of the protection member140is small, floating up is likely to occur. As in the present embodiment, the projection portion145may be formed on the opposite side of the sealing portion110(seeFIG.15A) of the print element substrate10. In this case, since the area from the end of the protection member140to the opening141of the protection member140is small, in a case where the projection portion145is deformed downward in the vertical direction, the protection member is likely to float up at the time of interference with the ejection surface120.

Therefore, in the present embodiment, as shown inFIG.17B, the ejection port forming member12is provided with the recessed portion12aso that the deformation of the projection portion145does not interfere with the ejection surface120. As a result, even in a case where the projection portion145is deformed downward in the vertical direction, the projection portion145and the ejection surface120do not interfere with each other, and it is possible to suppress floating up of the protection member140.

In the ejection port forming member12according to the present embodiment, in the case of forming an ejection port or a pressure chamber on the substrate11, the recessed portion12aof the ejection port forming member12is provided in a position where the ejection port forming member12corresponds to the projection portion145and is formed so as to expose the surface of the substrate11. A portion where the surface of the substrate11is exposed is located on the opposite side of the sealing portion110, and no main circuit is provided inside the substrate. Thus, even in a case where electrical noise is mixed from the portion where the substrate11is exposed, there is a low probability of being affected.

Further, as shown inFIG.17C, the recessed portion12bmay be formed in the ejection port forming member12so that the substrate11is not exposed. As a result, the height of the recessed portion in the vertical direction is reduced, so that the projection portion145becomes closer to the ejection port forming member12than the case of the recessed portion12awhere the surface of the substrate11is exposed. However, since the substrate11is covered with the protection member140, resistance to the electrical noise increases.

In the present embodiment, the projection portion145is formed by separating the connection between the material sheet and the protection member140. However, the projection portion145may also be provided in the protection member140on a side opposite to the side on which the projection portion145is formed. As shown inFIG.15A, the projection portion145is provided in the protection member140on the sealing portion110side (see a region F inFIG.15A). On the print element substrate10, since wiring in the substrate is routed from the sealing portion110side toward the ejection port array, a distance from the ejection port array14closest to the sealing portion110side of the print element substrate10to the end of the ejection port forming member12near the sealing portion110is long. As a result, in a case where the protection member140is arranged on the print element substrate10, the area of the protection member140on the sealing portion110side can be increased. In a case where a recessed portion corresponding to the projection portion145is provided in the position shown by the region F inFIG.15A, it is possible to further suppress floating up of the protection member140. On the other hand, in a case where no recessed portion is provided, it is possible to suppress electrical noise mixture due to exposure of the substrate11.

The shape of the recessed portion of the ejection port forming member12may be any shape as long as the projection portion145of the protection member140does not interfere with the ejection surface120in a case where the projection portion145of the protection member140is deformed vertically downward. For example, the shape of the recessed portion12bmay be a trapezoid, a semicircle, or a rectangle, as shown inFIGS.18A to18C. Further, it does not necessarily have to be the recessed portion, but an opening that can accommodate the projection portion145may also be provided. For example, as shown inFIGS.18D and18E, a square opening or a circular opening may be provided. The projection portion145can be accommodated in each of the provided openings. Thus, it is possible to suppress floating up of the protection member140due to interference between the projection portion145of the protection member140and the ejection surface120.

Second Embodiment

A second embodiment of the present disclosure will be described. Descriptions of functions and configurations similar to those in the first embodiment of the present disclosure will be omitted, and differences will be described.

FIG.19Ais a perspective view of a simplified print element substrate according to the second embodiment.FIG.19Bis a perspective view of a simplified print element substrate showing a modification ofFIG.19A.FIGS.20A and20Bare perspective views of a simplified print element substrate showing a modification ofFIG.19A. InFIGS.19A,19B,20A, and20B, a portion of the configurations is simplified to facilitate understanding.

The second embodiment is different from the first embodiment in that the recessed portions121are formed not between the adjacent ejection port arrays14, but to surround each of the plurality of ejection port arrays14, as shown inFIG.19A. With such a configuration, the number of adhered positions increases, so that the force of adhesion between the ejection surface120and the protection member140can be made stronger. Further, as one modification of the second embodiment, as shown inFIG.19B, the recessed portions121formed so as to surround each of the plurality of ejection port arrays14may be connected in a groove shape. With such a configuration, the force of adhesion between the ejection surface120and the protection member140can be made stronger. Furthermore, as another modification of the second embodiment, as shown inFIGS.20A and20B, in each ejection port array14arrayed at the end of the substrate10in the transverse direction, recessed portions121adifferent from the recessed portions121may also be formed outside the recessed portions121formed so as to surround the ejection port array. With such a configuration, in the case of wiring the flexible wiring substrate40only on one side of the substrate10in the transverse direction, the ejection surface120and the protection member140can be adhered more suitably, and the force of adhesion between the ejection surface120and the protection member140can be made stronger.

Third Embodiment

In a third embodiment according to the present disclosure, there is a case where an identification number200is formed on a functionally unaffected portion such as an end of the print element substrate10so that a manufacturing history can be determined, and such a configuration will be described. Descriptions of functions and configurations similar to those in the first and second embodiments of the present disclosure will be omitted, and differences will be described.

FIG.21Ais a partially enlarged view of the print element substrate10provided with the identification number200of the liquid ejection head3according to the third embodiment, andFIG.21Bis a schematic cross-sectional view taken along line XXIB-XXIB. Further,FIG.21Cis a partially enlarged view of the protection member140A of the liquid ejection head3according to the third embodiment.

As shown inFIG.21A, the ejection port forming member12according to the present embodiment is provided with the identification number200for determining the manufacturing history near a recessed portion of the ejection port forming member12. As shown inFIGS.21A and21C, the identification number200is formed so as to hollow out the ejection port forming surface12. As shown inFIG.21B, a recessed portion is formed in a protection member140A so that the protection member140A does not overlap the identification number200in a case where the protection member140A is attached to the print element substrate10. As a result, the identification number200formed on the ejection port forming member12can be visually observed while a recessed portion corresponding to the projection portion149is provided. Incidentally, the recessed portion is formed in the protection member140A so that the protection member140A does not overlap the identification number200in order to visually observe the identification number200, but the present disclosure is not limited to this, and an opening may also be formed so that the identification number200can be recognized.

This application claims the benefit of Japanese Patent Application No. 2023-069132, filed Apr. 20, 2023, which is hereby incorporated by reference wherein in its entirety.