The present disclosure relates to a liquid ejection head that ejects liquid and a liquid ejection apparatus including the same.
In mounting an inkjet printhead, which is a typical liquid ejection head that ejects liquid (hereinafter also referred to as a “printhead”), to an inkjet printing apparatus (hereinafter also referred to as a “printing apparatus”), positioning for the attachment needs to be accurate. For this reason, a printhead is provided with positioning portions used for positioning relative to a printing apparatus in terms of a conveyance direction in which a medium to be printed such as paper is conveyed (an X-direction), a direction which is along the surface of the medium to be printed and is orthogonal to the conveyance direction (a Y-direction), and a direction perpendicular to the surface of the medium to be printed (a Z-direction). The Z-direction is parallel to a liquid ejection direction.
In methods employed for conventional printheads, positioning is performed between an ink ejection member and a positioning member so that the positions of ejection ports that eject ink relative to the positioning portions fall within a predetermined accuracy, and then an adhesive is used to secure them. Also, as described in Japanese Patent Laid-Open No. 2011-31606 (hereinafter referred to as Literature 1), with a printhead being temporarily being secured to a positioning member secured to a jig, positional adjustments are made by movement in the X- and Y-directions, and the positioning member and the printhead are secured with a UV adhesive.
Using an adhesive to secure a positioning member to a printhead as described in the related art poses a concern where after the positioning, positional displacement may occur due to, e.g., contraction of the adhesive in curing or contraction of a member caused by heating performed in a case where a thermosetting adhesive is used. It is particularly difficult to position and secure a member accurately in a short period of time in a case where the member is complicated in shape, large, or relatively heavy.
Also, in a case of a printhead such that a positioning member is secured to the printhead using an adhesive, an external force applied to the positioning member in mounting of the printhead to a printing apparatus is transmitted to the adhesive, which makes it easy for deformation, peel-off, and the like to occur. For this reason, positional displacement may occur even after positioning is performed with the positioning member being secured to the printhead with an adhesive.
In a case of a full-line-type printhead in particular, because the printhead is elongated and large, a great force is needed to secure the printhead to the printing apparatus so that the printhead may be positioned accurately relative to the printing apparatus and secured not to move. This consequently makes it easy for positional shift to occur due to deformation of the adhesive, peel-off of the adhesive, and the like and increases the possibility of positional displacement of the printhead.
A liquid ejection head that ejects liquid, including: a liquid ejection member having a print element board including an ejection port surface where ejection ports for ejecting liquid are formed and a plurality of print elements that generate energy for ejecting the liquid from the ejection ports; and a positioning member to serve as a positioning portion for the liquid ejection head and the liquid ejection apparatus horizontally and vertically upon mounting of the liquid ejection head to the liquid ejection apparatus. The liquid ejection head has adjustment screws for adjusting the positions of the positioning member and the liquid ejection member and securing screws for coupling and securing the positioning member and the liquid ejection member, and the position of the positioning member is adjustable using the adjustment screws and the securing screws.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Embodiments of the present disclosure are described below with reference to the drawings.
The following descriptions use a printhead as a typical example of a liquid ejection head to which the present disclosure can be applied. However, the following descriptions are not intended to limit the scope of the present disclosure. Although the present embodiments use, as an example, the thermal method, in which liquid is ejected by generation of bubbles by heat generating elements, the present disclosure can be applied to a printhead employing any of the other various liquid ejection methods such as the piezoelectric method.
The printhead 100 is provided with a positioning member 200. The positioning member 200 is provided with reference faces, namely, Y abutment faces 210, X abutment faces 211, and Z abutment faces 212, to serve as abutment references for mounting of the printhead 100 to the printing apparatus 1000.
The printhead 100 can be positioned relative to the printing apparatus 1000 by having the positioning member 200 of the printhead 100 biased toward a guide member 500 of the printing apparatus 1000 using a leaf spring (not shown), an abutment mechanism (not shown), or the like. As long as the positioning member 200 of the printhead 100 is properly attached to the printhead 100, there is no need to make positional adjustments after the printhead 100 is attached to the printing apparatus 1000. Thus, the positions of ejection ports can be reproduced even after repeated detachment and attachment of the printhead 100, and the quality of printed images can be maintained at high quality.
The ejection unit 90 has a print element board 11 and a base member 10 including the print element board 11. As seen in
Flow channels (not shown) for supplying liquid to the print element board 11 are formed in the base member 10. The base member 10 is not limited to having an integral configuration, and may have a configuration such that a resin member where flow channels are formed is coupled to a support member made of metal to maintain rigidity. The base member 10 is further provided with tap holes 22 for attaching adjustment parts 20 to be described later and through-holes 31 for inserting securing parts 30.
In order to serve as abutment references in mounting of the printhead 100 to the printing apparatus 1000, the positioning member 200 has the following reference faces: the Y abutment faces 210, the X abutment faces 211, and the Z abutment faces 212. These reference faces include a convex shape as well to have a smaller area of contact with the printing apparatus 1000. The positioning member 200 is attached at a position so that the X- Y- and Z-positions of the ejection ports 12 of the print element board 11 may be optimal positions. This improves the accuracy of the positional relation between the printing apparatus 1000 and the ejection ports 12 in the mounting of the printhead 100 to the printing apparatus 1000, and consequently, print image quality improves. The positioning member 200 is provided with tap holes 203 for attaching the securing parts 30.
As will be described later, the positioning member 200 is secured to the ejection unit 90 using the adjustment parts 20 and the securing parts 30.
The adjustment parts 20 define the distance between the positioning member 200 and the ejection unit 90 in the Z-direction (a distance in the ejection direction) at their optimal positions. For example, the adjustment parts 20 may be screws. Preferably, the adjustment parts 20 are screws with spherical tips. The screw-type adjustment parts (hereinafter also referred to as “adjustment screws”) 20 may have, for example, slots, cross recesses, hexagon sockets, or the like formed at their screw heads so that the adjustment screws 20 can be fastened using a tool such as a screw driver or a hexagon wrench.
The adjustment screws 20 are inserted through the tap holes 22 opened in the base member 10, with their tips 21 being in contact with the positioning member 200. In a case where the tips 21 have spherical shapes, the contact states of the tips 21 are not changed by slanting of the positioning member 200. Moreover, in a case where a plurality of adjustment screws 20 are used, the adjustment screws 20 have equivalent areas of contact, and the plurality of adjustment parts 20 can come into contact with the positioning member 200 equally.
The securing parts 30 secure the ejection unit 90 to the positioning member 200. The securing parts 30 can secure the positioning member 200 to the base member 10 of the ejection unit 90 by passing through the through-holes 31 opened in the base member 10 and being fastened into the tap holes 203 opened in the positioning member 200.
The securing parts 30 may be screws. The screw-type securing parts (hereinafter also referred to as “securing screws”) 30 have, for example, slots, cross recesses, hexagon sockets, or the like formed at their screw heads so that the securing screws 30 can be fastened using a tool such as a screw driver or a hexagon wrench. Also, securing parts 30 with spring washers or flat washers may be used.
As seen in
Meanwhile, in a case where the securing screws 30 are disposed outside of the triangle 300, a force exerted by fastening of the securing screw 30 produces such a force that raises the positioning member 200 with a line connecting two adjustment screws 20 acting as a rotation axis, and the positioning member 200 may be displaced.
There is no limitation as to the number of the adjustment screws as long as there are three or more of them.
The following describes assemblage of the printhead 100. The positioning member 200 can be secured to the ejection unit 90 as follows. Positional adjustments are made so that the X-, Y-, and Z-positions of the ejection ports 12 and the X-, Y-, and Z-positions of the positioning member may be at proper positions, and height adjustments of the adjustment screws 20 are made. Then, the securing screws 30 are fastened to achieve securing while maintaining the high-accuracy positions.
Adjustment and assemblage are performed in the assemblage process of the printhead 100 as described below for example so that the positions to serve as the X-, Y-, and Z-references for the positioning member 200 may be at proper positions.
The assemblage apparatus 2000 is equipped with cameras 2300 for imaging the positions of the ejection ports 12 of the print element board 11 disposed at the ejection unit 90.
Further, the assemblage apparatus 2000 has abutment references 2100 with which the position of the positioning member 200 is brought into abutment. The abutment references 2100 can determine the position of the positioning member 200. Note that the shapes of the abutment references 2100 are desirably equivalent to the shapes of the abutment references on the printing apparatus side for mounting of the printhead 100 to the printing apparatus 1000.
The positional relation between the target positions in the cameras 2300 and the abutment portions of the abutment references 2100 are adjusted in advance to be optimal values.
Next, as shown in
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In this state, as shown in
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In this way, in the present embodiment, the positioning member 200 can be secured in position without interposition of an adhesive. In mounting of the printhead 100 to the printing apparatus 1000, loads are applied to the positioning member 200 and rigidity parts such as the adjustment screws 20 and the securing screws 30, and consequently, a positional change due to, e.g., deformation of an adhesive or peel-off of an adhesive does not occur. Not using an adhesive for the coupling eliminates the need for a heating step for curing a thermosetting adhesive and therefore does not induce deformation of the ejection unit 90 due to the heat in the heating step. Also, the assemblage can be done without a dwell time for curing.
Further, the positioning member 200 can be assembled in the final step of the assemblage process of the printhead 100. For this reason, the positioning member 200 can be adjusted and assembled with respect to the position of the print element board 11 in the final shape, without being affected by component tolerance and assemblage error that affect accuracy nor by inaccuracy due to thermal deformation caused by, e.g., heating performed to cure an adhesive at the time of assemblage. As a result, the assemblage can be done with higher positional accuracy.
In a case where there is a concern of loosening of screws due to shaking, vibration, and the like during transport of the printhead 100 or the printing apparatus 1000, loosening of the screws can be prevented by application of an anaerobic loosening-prevention adhesive to the thread portions of the adjustment screws 20 and the securing screws 30. Because the anaerobic loosening-prevention adhesive applied here cures not by heating or UV radiation but by reacting to metal ions with air being shut off, only the gaps between the thread lines are embedded, and the anaerobic loosening-prevention adhesive is not affected by inaccuracy caused by thermal deformation. Further, coupling between the positioning member 200 and the adjustment and securing screws 20, 30 and coupling between the ejection unit 90 and the adjustment and securing screws 20, 30 per se are done with the rigidity parts being in contact with each other. Thus, even in a case where the positioning member 200 receives an external force, a positional change due to deformation of the loosening-prevention adhesive, peel-off of an adhesive, or the like do not occur.
In a second embodiment, the positioning member 200 is divided into a first positioning member 201 and a second positioning member 202 and disposed at the respective end portions of an ejection unit 92.
The X-, Y-, and Z-reference positions of the printhead 120 are formed by both of the first positioning member 201 and the second positioning member 202. In the present embodiment, the Y abutment face 210 and the X abutment face 211 are formed at the first positioning member 201, and the X abutment face 211 is formed at the second positioning member 202 (see
Dividing the positioning member 200 into two members enables size reduction of the positioning member. Also, an element for twisting and warpage of the positioning member itself can be eliminated.
A printhead is elongated and large in a case where the printhead is a full-line-type printhead in which a plurality of print element boards 11 are arranged. Thus, great force is needed to secure such a printhead in order for the printhead to be accurately positioned relative to the printing apparatus and secured not to move. This consequently makes it likely to cause positional change due to deformation of an adhesive, peel-off of an adhesive, or the like and increases the possibility of positional displacement of the printhead. However, dividing the positioning member 200 into two members can reduce warpage of the positioning member and is therefore preferable.
The securing screws 30 are preferably disposed inside of a polygon formed by connecting a plurality of adjustment screws, as in the first embodiment. Further, in a case where one securing screw is used for one positioning member with no ejection unit 92 or interferer inside the polygon formed by a plurality of adjustment screws as in
Also, in a case where the securing screws 30 are disposed at the middle points 303 of the respective sides of the polygon 300 formed by the adjustment screws 20 as in
A third embodiment relates to a printhead 130 such that the shape for positioning between a printhead 120 and the printing apparatus 1000 in the second embodiment is modified. In the present embodiment, a concave portion 250 formed at a first positioning member 231 of the printhead 130 and a groove portion 260 and a flat portion 270 formed at a second positioning member 232 of the printhead 130 are brought into abutment with spherical guide members 901 to enable positioning of the printhead in the X-, Y-, and Z-directions.
Positional adjustment and securing of the first positioning member 231 and the second positioning member 232 to an ejection unit 93 in the present embodiment are done using a method similar to the second embodiment and are therefore not described here.
The printhead 130 is set in the printing apparatus 1300 with the ejection ports 12 facing downward in the Z-axis direction, as in
The flat portion 270 may be formed in either one of the first positioning member 231 and the second positioning member 232, but in the present embodiment, the flat portion 270 is formed at the second positioning member 232.
The concave portion 250 and the groove portion 260 are shaped so that they fit in the respective spherical guide members 901 by coming into abutment therewith and are as a result at positions where they do not move relative to the spherical guide members 901. The radius of the conical concave portion 250 and the width of the V-shape groove 260 may be any sizes as long as they can come into abutment with the spheres 901 and secured. Too small sizes make them unable to hold the printhead 130, causing wobbling or slanting. Too large sizes, on the other hand, make the spheres 901 unable to be centered properly in a case where the concave portion 250 is conical. Also, too wide a groove 260 makes the spheres 901 unable to be supported by both side surfaces of the groove 260, causing wobbling and slanting.
With the method employed herein, the X- and Y-positions of the printhead 130 are determined at optimal positions only by its own weight and biasing in the Z-direction; thus, there is no need to bias the head in the X- and Y-directions. For this reason, positioning is accomplished only by placing the printhead 130 on the spherical guide members 901 and biasing the printhead 130 in the Z-direction, without needing any positional adjustment after mounting.
The adjustment method is similar to the assemblage method in the first embodiment and is therefore not described here, and the following only describes abutment references used to bring the positioning member into abutment with jigs in assemblage of the positioning member. The jig with which the first positioning member 231 comes into abutment has a sphere with the same diameter as the spherical guide members 901 of the printing apparatus 1300 and determines the position by bringing the sphere into abutment. However, only with the sphere, the first positioning member 231 would slant. Thus, a guide pin is placed to keep the positioning member horizontal. The jig with which the groove portion 260 of the second positioning member 232 comes into abutment uses a shaft with the same diameter as the spherical guide members 901 of the printing apparatus 1300 and thereby can determine the position while performing positional restriction including the slanting of the second positioning member 232. Also, the jig with which the flat portion 270 of the second positioning member 232 comes into abutment can determine the position at a certain height by having an abutment pin disposed at a position corresponding to the position with which the spherical guide member 901 of the printing apparatus is to come into abutment.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2022-193616, filed Dec. 2, 2022, which is hereby incorporated by reference wherein in its entirety.
Number | Date | Country | Kind |
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2022-193616 | Dec 2022 | JP | national |