Patent Grant
6945635
1. Field of the Invention
The present invention relates to a liquid discharge head for discharging liquid by creating a bubble (bubbles) with thermal energy acting upon liquid, and the method of manufacture therefor. The invention also relates to a liquid discharge apparatus that uses such liquid charge head.
Also, the present invention is applicable to a printer that records on a recording medium, such as paper, thread, fabric, cloth, leather, metal, plastic, glass, wood, ceramic, a copying machine, a facsimile equipments provided with communication system, and a word processor having a printing unit therefor. The invention further relates to an industrial recording apparatus formed complexly in combination with various processing apparatuses.
In this respect, the term “recording” referred to in the specification of the invention hereof not only means the provision of characters, graphics, and other meaningful images for a recording medium, but also, means the provision of images, such as patterns, which are not meaningful.
2. Related Background Art
Conventionally, for the so-called bubble jet recording method has been known, which is an ink jet recording method for forming images by the adhesion of ink onto a recording medium by discharging ink from discharge ports by the acting force based upon the abrupt voluminal changes following the creation of bubble by applying thermal energy or the like to liquid ink in flow paths of a recording apparatus, such as a printer. As disclosed in the specification of the U.S. Pat. No. 4,723,129, the recording apparatus that uses this bubble jet recording method is generally provided with discharge ports to discharge ink; flow paths communicated with these discharge ports; and electrothermal converting elements arranged in the flow paths to serve as energy generating means.
In accordance with a recording method of the kind, it becomes possible to record high quality images at high speeds in a lesser amount of noises, and at the same time, to arrange discharge ports for discharging ink in high density for the head using this recording method with such an excellent advantage, among some others, that recorded images are obtained in high resolution even in colors with a smaller apparatus. Therefore, the bubble jet recording method has been widely utilized for a printer, a copying machine, a facsimile equipment, and other office equipment in recent years. Further, this method has been utilized even for an industrial system, such as a textile printing apparatus.
Along with the wider utilization of bubble jet technologies and techniques for the products in various fields, there are increasingly more demands in various aspects. Then, for example, in order to obtain higher quality images, there has been proposed the driving condition whereby to provide a liquid discharge method or the like that performs excellent ink discharges at higher speeds based upon the stabilized creation of bubble or in consideration of the achievement of higher recording, there has been proposed the improved flow path configurations for obtaining a liquid discharge head having a higher refilling speed of liquid into the liquid flow path where liquid has been discharged.
Of these proposals, for the head that discharges liquid along with the growth and shrinkage of bubble created in nozzles, it has been known that the efficiency of discharge energy and the refilling characteristics of liquid tend to become unfavorably by the bubble growth in the direction opposite to the corresponding discharge port, and the resultant liquid flow caused thereby. The invention of a structure in which to enhance the discharge energy efficiency, as well as the refilling characteristics of the kind has been proposed in the specification of the European Patent Laid-Open Application EP-0436047A1.
The invention disclosed in the specification of this European Laid-Open Application is such that a first valve that cuts off the connection between the area near the discharge port and the bubble generating area, and a second valve that cuts off the connection between the bubble generating area and the ink supply portion completely, and that these valves are open and closed alternately (see
However, in accordance with the invention described in the specification of the EP436047A1, the three chambers for the area near the discharge port, the bubble generating portion, and the ink supply portion are divided into two each. Therefore, ink that follows the ink droplet becomes a long tail when discharged, and satellites may ensue inevitably more than the usual method of discharge where the growth, shrinkage, and extinction of bubble are carried out (presumably, because the effect of the meniscus retraction that may be produced by the bubble extinction is not usable). Also, the valve on the discharge port side of the bubble tends to invite a great loss of discharge energy. Moreover, at the time of refilling (when ink is replenished for the nozzle), liquid cannot be supplied to the area near the discharge port until the next bubbling takes place, although liquid is supplied to the bubble generating portion along with the extinction of bubble. As a result, not only the fluctuation of discharged droplets is greater, but the frequency of discharge responses becomes extremely smaller, hence making this method far from being practicable.
With the present invention, it is intended to propose the devise to enhance the discharge efficiency satisfactorily based upon a new idea whereby to find an epoch-making method and head structure by improving the efficiency of suppression of the bubble growing component in the direction opposite to the discharge port, while satisfying the higher enhancement of the refilling characteristics, which is directly-opposed idea of providing more suppression on such component of growing bubble on the opposite side of the discharge port.
As a result of the assiduous studies made by the inventors hereof, it has been found to be able to utilize the discharge energy directed backward on the discharge port side effectively by means of check-valve mechanism specially constructed in the nozzle structure of a liquid discharge head that discharges liquid along with the growth of bubble created in the nozzle which is linearly formed. Here, with the special check-valve mechanism, the growing component of bubble directed backward is suppressed, and at the same time, the refilling characteristics are made more efficient. It has been found then that the frequency of discharge responses is made higher significantly.
In other words, it is an object of the present invention to establish a new discharging method (structure) whereby to attain a head capable of obtaining the high quality images at high speed, which have never been obtainable with the conventional art, with the nozzle structure and discharging method that use a novel valve mechanism.
The liquid discharging method of the present invention obtained in the process of the aforesaid studies of the liquid head discharge head, which is provided with a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated always with each of the discharge ports at one end, each having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a plurality of liquid supply ports each arranged for each of the liquid flow paths to be communicated with common liquid supply chamber; and movable member supported with minute gap to the liquid supply port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, comprises the step of setting a period for the movable member to close and essentially cut off the opening area during the period from the application of driving voltage to the bubble generating means to the substantial termination of isotropical growth of the entire bubble by the bubble generating means.
Also, for the aforesaid liquid discharging method, the period for the movable member to close and essential cut off the opening area continues at least until the termination of the period of substantially isotropical growth of the entire bubble by the bubble generating means.
Further, for the aforesaid liquid discharging method, during the growing period of the portion of the bubble created by the bubble generating means on the discharge port side after the period for the movable member to close and substantially cut off the opening area, the movable member begins to be displaced from the position of closing and substantially cutting off the opening area to the bubble generating means side in the liquid flow path, and makes liquid supply possible from the common liquid supply chamber to the liquid flow path.
Further, after the movable member begins to be displaced from the position of closing and substantially cutting off the opening area to the bubble generating means side in the liquid flow path, the movable member is further displaced to the bubble generating means side during the shrinking period of the portion of the bubble on the movable member side to supply liquid from the common liquid supply chamber to the liquid flow path.
Further, the voluminal changes of bubble growth and the period from the generation of bubble to the extinction thereof on the bubble generating area are different largely on the discharge port side and the liquid supply port side.
The liquid discharge head of the present invention comprises a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated always with each of the discharge ports at one end, each having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a plurality of liquid supply ports each arranged for each of the liquid flow paths to be communicated with common liquid supply chamber; and movable member supported with minute gap of 10 μm or less to the liquid supply port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, and the discharge port and the bubble generating means being in linearly communicative state.
Also, the liquid discharge head of the present invention comprises a discharge port for discharging liquid; a liquid flow path communicated always with the discharge port at one end, having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a liquid supply port arranged for the liquid flow path to be communicated with common liquid supply chamber; and movable member supported with minute gap of 10 μm or less to the liquid supply port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, and the discharge port and the bubble generating means being in linearly communicative state.
For these liquid discharge heads, it is preferable to provide the movable member also with gaps to with flow path walls forming the liquid flow path.
Also, the liquid discharge head of the present invention comprises a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated always with each of the discharge ports at one end, each having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a plurality of liquid supply ports each arranged for each of the liquid flow paths to be communicated with common liquid supply chamber; and movable member supported with minute gap to the liquid supply-port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, and having a period for the movable member to close and essentially cut off the opening area during the period of substantially isotropical growing of the entire bubble by the bubble generating means on the discharge port side after the application of driving voltage to the bubble generating means, and the movable member beginning to be displaced from the position of closing and essentially cut off the opening area to the bubble generating means side in the liquid flow path during the period of the portion of bubble created by the bubble generating means on the discharge port side being grown after the period of the same movable member to close and essentially cut off the opening area, making liquid supply possible from the common liquid supply chamber to the liquid flow path. For this liquid discharge head, given the maximum volume of bubble growing in the bubble generating area on the discharge port side as Vf, and given the maximum volume of bubble growing in the bubble generating area on the liquid supply port side as Vr, the relationship of Vf>Vr is established at all times.
In this case, given the life time of bubble growing in the bubble generating area on the discharge port side as Tf, and given the life time of bubble growing in the bubble generating area on the liquid supply port side as Tr, the relationship of Tf>Tr is established at all times.
Then, the point of the bubble extinction is positioned on the discharge port side from the central portion of the bubble generating area.
Also, the liquid discharge head of the present invention comprises a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated always with each of the discharge ports at one end, each having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a plurality of liquid supply ports each arranged for each of the liquid flow paths to be communicated with common liquid supply chamber; and movable member supported with minute gap to the liquid supply port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, and the free end of the movable member being minutely displaced in the liquid flow path to the liquid supply port side in the initial stage of the bubble creation, and along with the bubble extinction, the free end of the movable member is largely displaced in the liquid flow path to the bubble generating means side for supplying liquid from the common liquid supply chamber into the liquid flow path through the liquid supply port.
In this case, the amount of displacement of the free end of the movable member is defined as h1 as the amount of displacement in the liquid flow path to the liquid supply port side in the initial stage of the bubble creation, and when the free end of the movable member is displaced in the liquid flow path to the bubble generating means side along with the bubble extinction, the amount of displacement thereof is defined as h2, and then, the relationship of h1<h2 is established at all times.
For each of the aforesaid liquid discharge heads, thin film of amorphous alloy is provided for the uppermost surface of the bubble generating means. Then, it is conceivable that the aforesaid amorphous alloy is an alloy of at least one metal or more selected from tantalum, iron, nickel, chromium, germanium, ruthenium.
Further, for the aforesaid liquid discharge head, it is preferable to integrally form the food supporting member with the movable member to support the foot of the movable member, and provide such member with a step for deviating the height position of the movable member by one step to the fixing position of the foot supporting member, and to make the thickness of the movable member larger than the amount of such step.
Further, it is preferable to arrange the relationship between a gap α between the opening edge of the liquid supply port on the liquid flow path side and the face of the movable member on the liquid flow supply port side, and the overlapping width W3 of the movable member in the widthwise direction overlapping with the opening edge of the liquid supply port on the liquid flow path side to be W3>α.
Further, it is preferable to arrange the relationship between the overlapping width W4 of the movable member in the discharge port direction overlapping with the opening edge of the liquid supply port on the liquid flow path side, and the overlapping width W3 of the movable member in the widthwise direction to be W3>W4.
The present invention also provides a liquid discharge apparatus which comprises a liquid discharge head structured as described above, and recording medium carrying means for carrying a recording medium receiving liquid discharge from the liquid discharge head. With this liquid discharge apparatus, it is conceivable to discharge ink from the liquid discharge head for recording by the adhesion of the ink to the recording medium.
Also, the method of the present invention for manufacturing a liquid discharge head, which is provided with a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated always with each of the discharge ports at one end, each having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a plurality of liquid supply ports each arranged for each of the liquid flow paths to be communicated with common liquid supply chamber; and movable member supported with minute gap to the liquid supply port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, comprises the steps of forming and patterning a first protection layer with respect to the area covering the portion of the elemental base plate provided with the bubble generating means becoming the liquid flow path; forming a first wall material used for the formation of the liquid flow path on the surface of the elemental base plate including the first protection layer; removing the portion of the first wall material becoming the liquid flow path; burying the portion of the first wall material becoming the removed liquid flow path; smoothing the entire surface of the first wall material by polishing; forming a second protection film on the smoothed first wall material for the formation of a fixing portion for the first wall material and the movable member; forming by patterning the material film becoming the movable member in a smaller width than the portion becoming the liquid flow path on the location corresponding to the portion becoming the liquid flow path; forming on the circumference of the material film becoming the movable member a gap formation member to form a gap between the movable member and the liquid supply port; forming on the first wall material a second wall material for the formation of the liquid supply port on the base plate including the gap formation member; forming the portion of the second wall material becoming the liquid supply port so as to make the opening area thereof smaller than the material film becoming the movable member; removing by resolving the first protection layer used for burying the gap formation member, the second protection layer, and the portion of the first wall material becoming the liquid flow path; and bonding the ceiling plate provided with the common liquid supply chamber to the base plate produced in the steps up to the previous stage.
Also, the method structured as described above for manufacturing a liquid discharge head, which is provided with a plurality of discharge ports for discharging liquid; a plurality of liquid flow paths communicated always with each of the discharge ports at one end, each having bubble generating area for creating bubble in liquid; bubble generating means for generating energy to create and grow the bubble; a plurality of liquid supply ports each arranged for each of the liquid flow paths to be communicated with common liquid supply chamber; and movable member supported with minute gap to the liquid supply port on the liquid flow path side, and provided with free end, the area of the movable member surrounded at least by the free end portion and both sides continued therefrom being made larger than the opening area of the liquid supply port facing the liquid flow path, comprises the steps of forming and patterning a first protection layer with respect to the portion of the ceiling plate becoming the walls of the liquid flow path; forming on the portion of the ceiling plate having none of the first protection layer a gap formation member for the formation of a gap between the movable member and the liquid supply port; forming the material film becoming the movable member on the entire surface of the first protection layer and the gap formation member; forming the material film becoming the movable member with a pattern larger than the opening area of the portion becoming the liquid supply port, and forming through holes on the movable member to facilitate flowing in liquid to resolve the gap formation member; forming by dry etching the common liquid supply chamber with the gap formation member as etching stop layer; removing the gap formation member; forming the liquid supply port by wet etching anisotropically the portion of the ceiling plate having none of the first protection layer; burying the through holes of the movable member with the same material as the material film becoming the movable member, and coating with the film the walls on the etching side; bonding the elemental base plate provided with the wall member for the formation of the liquid flow path and the bubble generating means to the member produced in the steps up to the previous stage.
With the structure described above, the movable member cuts off immediately the communicative condition between the liquid flow path and the liquid supply port during the period from the application of driving voltage to the bubble generating means to the termination of substantially isotropical growth of bubble by the bubble generating means. As a result, the waves of pressure exerted by the bubble growth in the bubble generating area is not propagated to the liquid supply port side and the common liquid supply chamber side. Most of all the pressure is directed toward the discharge port side. Thus, the discharge power is enhanced remarkably. Also, even when a highly viscous recording liquid is used for a higher fixation on a recording sheet or the like or used for the elimination of spreading on the boundary between black and other colors, it becomes possible to discharge such liquid in good condition due the remarkable enhancement of discharge power. Also, the environmental changes at the time of recording, particularly, under the environment of lower temperature and lower humidity, the overly viscous ink region tends to increase, and in some cases, ink is not normally discharged when beginning its use. However, with the present invention, it is possible to perform discharging in good condition form the very first shot. Also, with the remarkably improved discharge power, the size of the heat generating element that serves as bubble generating means can be made smaller or the input energy can be made smaller.
Also, along with the shrinkage of bubble, the movable member is displaced downward to enable liquid to flow from the common liquid supply chamber into the liquid flow path in a large quantity at a rapid flow rate through the liquid supply port. In this manner, the flow that draws meniscus into the liquid flow path is quickly reduced after the droplet is discharge, and the amount of meniscus retraction is made smaller at the discharge port accordingly. As a result, the meniscus returns to the initial state in an extremely short period of time. In other words, the replenishment of a specific amount of ink into the liquid flow path (refilling) is very quick, hence remarkably enhancing the discharge frequency (driving frequency) when executing highly precise ink discharge (in a regular quantity).
Further, in the bubble generating area, the bubble growth is large on the discharge port side, while suppressing the growth thereof toward the liquid supply port side. Therefore, bubble extinction point is positioned on the discharge port side from the central portion of the bubble generating area. Then, while maintaining the discharge power, it becomes possible to reduce the power of bubble extinction. This makes it possible to protect the heat generating member from being mechanically and physically destructed by the bubble extinction in the bubble generating area, and contribute to improving its life significantly.
Also, the foot supporting member is integrally formed with the movable member to support the foot of the movable member, which is provided with a step so that the height position of the movable member is deviated by one step from the fixing position of the foot supporting member. With this arrangement, when the movable member is displaced, the concentration of stress on the fixing position of the foot supporting member of the movable member is relaxed. Further, the thickness of the movable member is made larger than the stepping amount of the foot supporting member of the movable member, hence making it possible to enhance the durability of the foot portion of the movable member, because the concentration of stress is relaxed when it is concentrated on the stepping portion of the foot supporting member of the movable member when the movable member is displaced.
Further, the relationship between the gap α between the opening edge of the liquid supply port on the liquid flow path side and the face of the movable member on the liquid supply port side, and the overlapping with W3 of the movable member in the widthwise direction, is overlapped with opening edge of the liquid supply port on the liquid flow path side is established to be W3>α. Thus, as compared with the case where this relationship is W3≦α, the flow resistance becomes greater in the flow from the liquid flow path to the liquid supply port side to make it possible to effectively suppress the flow from the liquid flow path to the liquid supply port side at the bubble initiation of the bubble growth. Further, it is possible to effectively suppress the flow from the liquid flow path into the liquid supply port through the gap between the movable member and the circumference of the liquid supply port. As a result, the movable member is able to shield the liquid supply port reliably and quickly. With this operation, the discharge efficiency is enhanced still more.
Also, the relationship between the overlapping width W4 of the movable member in the discharge port direction, which is overlapped with the opening edge of the liquid supply port on the liquid flow path side, and the overlapping width W3 in the widthwise direction of the movable member is established to be W3>W4. With this arrangement, the contact width between the free end tip of the movable member and the opening edge of the liquid supply port becomes smaller when the movable member, which has been displaced upward to the liquid supply port side by the initial bubbling, begins to be displaced downward to the bubble generating means side in the process of the bubble extinction. As a result, the friction force that may be generated at that time is reduced to make it possible to release the liquid supply port priorly from the free end side of the movable member. This makes the releasing of the liquid supply port by the movable member reliably and quickly. Consequently, refilling into the liquid flow path is carried out more efficiently to stabilize the discharge characteristics.
Also, with the adoption of thin film of amorphous alloy for the cavitation proof film on the uppermost surface layer of bubble generating means, it becomes possible to make its life longer against the mechanical and physical destruction.
Also, in the manufacturing processes of the liquid discharge head in accordance with the present invention, the adoption of the amorphous alloy makes it possible to considerably reduce the damages that may be caused to the wiring layer which is arranged on the lower layer even in the removal step whereby to remove the Al film for the formation of the liquid flow path and liquid supply port as well. This contributes significantly to enhancing the production yield.
The other effects and advantages of the present invention will be understandable from the description of each embodiment which is given below.
In this respect, the terms “upstream” and “downstream” used for the description of the present invention are the expressions to indicate the liquid flow in the direction toward the discharge port from the supply source of liquid through the bubble generating area (or through the movable member) or to indicate the direction on the structural aspect thereof.
Also, the term “downstream side” of bubble itself means the downstream side of the center of the bubble in the aforesaid flow direction or the aforesaid structural direction, or it means the bubble to be created on the area on the downstream side of the central area of the heat generating element.
Also, the term “overlapping width” indicates the minimal distance from the opening edge of the liquid supply port on the liquid flow path side to the edge portion of the movable member.
Also, the expression “the movable member closes and essentially cuts off the liquid supply port” used for the present invention does not mean that the movable member is necessarily in contact closely with the circumference of the liquid supply port, but it means to include a condition where the movable member approaches the liquid supply port as close as possible.
Now, hereinafter, with reference to the accompanying drawings, the description will be made of the embodiments in accordance with the present invention.
(First Embodiment)
For the liquid discharge head shown in
For each of many numbers of liquid flow paths 3, there is arranged the liquid supply port 5 which is formed for a supply unit formation member 5A. Then, the common liquid supply chamber 6 of a large capacity is arranged to be communicated with each of the liquid supply ports 5 at a time. In other words, the configuration is arranged so that a plurality of liquid flow paths 3 are branched from one single common liquid supply chamber 6, and ink is supplied from this common liquid supply chamber 6 in an amount corresponding to the liquid which has been discharged from the discharge port 7 communicated with each of the liquid flow paths 3.
Between the liquid supply port 5 and the liquid flow path 3, a movable member 8 is arranged substantially in parallel to the opening area S of the liquid supply port 5 with a minute gap α (10 μm or less, for instance) therewith. The movable member 8 is positioned to the elemental base plate 1, and also, substantially in parallel to the elemental base plate 1. Then, the end portion 8B of the movable member 8 on the discharge port 7 side is made a free end positioned on the heat generating element 4 side of the elemental base plate 1. The foot supporting member 8C which supports the foot of the movable member 8 is integrally formed with the movable member 8. The foot supporting member 8C is the member that connects and commonly supports a plurality of movable members 8 arranged side by side in the direction intersecting a plurality of liquid flow paths. A reference numeral 8A in FIG. 1 and
Further, for the present embodiment, the area surrounded at least by the free end portion and the both side portions of the movable member 8 that continue therefrom is made larger than the opening area S of the liquid supply port 5 (see FIG. 3), and the minute gap β is arranged between side portions of the movable member 8 and the flow path walls 10 on both sides thereof, respectively (see FIG. 2). The aforesaid supply unit formation member 5A has a gap γ with the movable member 8 as shown in FIG. 2. Although the gaps β and γ are different depending on the pitches of the flow paths, the larger the gap γ, the easier the movable member 8 is able to shield the opening area S, and the larger the gap β, the easier becomes the movable member 8 to shift to the elemental base plate 1 side along with the extinction of bubble than the steady state in which the movable member is positioned through the gap α. For the present embodiment, the gap α is 2 μm; the gap β is 3 μm; and the gap γ is 4 μm. Also, the movable member 8 has the width W1 which is larger than the width W2 of the opening area S described above in the widthwise direction between the flow path side walls 10, which is a width being able to sufficiently close the opening area S. In accordance with the present embodiment, the thickness of the portion that follows the movable member 8 of the supply unit formation member 5A is made smaller than the thickness of the liquid flow path wall 10 itself as shown in FIG. 2 and
The opening area S referred to herein is the area where liquid is essentially supplied from the liquid supply port 5 toward the liquid flow path 3, and for the present embodiment, this opening area is the one surrounded by the three sides of the liquid supply port 5 and the edge portion 9A of the fixing member 9 as shown in FIG. 1 and FIG. 3.
Also, as shown in
Now, the detailed description will be made of the discharge operation of the liquid discharge head in accordance with the present embodiment.
In the isotropically growing step of the bubble 21 at the bubbling initiation, the movable member 8 closes the liquid supply port 5 by being closely in contact with the circumference of the liquid supply port 5, and the interior of the liquid flow path 3 becomes essentially closed with the exception of the discharge port 7. This closed condition is maintained in some period in the isotropical growing step of the bubble 21. Here, the period during which the closed condition is maintained may be the one from the application of driving voltage to the heat generating element 4 to the termination of the isotropical growing step of the bubble 21. Also, in this closed state, the inertance (hardness of movement when liquid moves from its stationary condition) on the liquid supply port side from the center of the heat generating element 4 in the liquid flow path 3 becomes essentially infinite. At this juncture, the inertance from the heat generating element 4 to the liquid supply port side is closer to infinity if the distance becomes more between the heat generating element 4 and the movable member 8. Here, also, the maximum amount is defined as h1 for the free end of the movable member 8 displaced to the liquid supply port 5 side.
Here, in conjunction with
Here, when the heat generating element 4 is being heated, the area where no bubble is grown on the heat generating element 4 is defined as area B for the convenience' sake of the description, and the area on the discharge port 7 side where the bubble is grown is defined as area A. In this respect, the bubbling volume becomes maximum in the area B shown in FIG. 8E. The bubbling volume at this time is defined as Vr.
Now,
Lastly, when the bubble 21 is completely extinguished, the movable member 8 also returns to the regular position shown in FIG. 5A. The movable member 8 is displaced upward to this state by the elastic force thereof (the direction indicated by a solid line arrow mark in FIG. 7B). Also, in this sate, the meniscus M has already returned to the vicinity of the discharge port 7.
Now, with reference to
As shown in
Particularly, in
Now, in accordance with the devise of bubble growth described above, the movable member presents the behavior given below in a mode where a part of the heat generating element is covered by the free end of the movable member as shown in FIG. 1. In other words, during the period (1) in
Such correlation as this between the bubble growth and the behavior of the movable member is influenced by the relative positions of the movable member and the heat generating element. Here, with reference to
In this respect, the general operation has been described as to the positional relations between the movable member 8 and the heat generating element 4, and the respective operations become different depending on the position of the free end of the movable member, and the rigidity of the movable member, among some others.
Also, as understandable form the representation of
Further, as understandable form FIG. 5B and
The head structure of the present embodiment and the liquid discharge operation thereof have been described as above. In accordance with the embodiment, the growing component of the bubble to the downstream side and the growing component thereof to the upstream side are not even, and the growing component to the upstream side becomes almost none, hence suppressing the liquid shift to the upstream side. With this suppression of liquid flow to the upstream side, there is almost no loss that may be incurred on the growing component of bubble on the upstream side. Most of all the components thereof are directed toward the discharge port, and enhance the discharging power significantly. Moreover, along with the shrinkage of bubble, the movable member is displaced downward to enable liquid to flow into the liquid flow path as a rapid and large liquid flow from the common liquid supply chamber through the liquid supply port. As a result, the flow that tends to draw the meniscus M into the liquid flow path 3 rapidly is made smaller at once. Then, the retracted amount of meniscus after discharge is reduced, and the degree of meniscus to be projected from the orifice surface is also reduced accordingly at the time of refilling. This contributes to suppressing the vibrations of meniscus, thus stabilizing liquid discharges at any driving frequency, lower to higher ones.
(Second Embodiment)
For the head structure of the first embodiment, the position of the foot supporting member 8C of the movable member 8, which is not to be in contact with the fixing member 9 (that is, bent to rise) as shown in
Also, as shown in
In this respect, the linearly sectional view of 2—2 in FIG. 12 and the linearly sectional view of 2—2
(Third Embodiment)
Further, for each of the embodiments described above, it is more preferable to make the thickness t of the movable member 8 larger than the stepping amount h of the foot supporting member 8C of the movable member 8 as shown in
Also,
As represented in
(Fourth Embodiment)
Further, it is possible to enhance the discharge efficiency for each of the embodiments described above by arranging, as shown in
In this respect, in conjunction with
On the other hand, in the relationship of W3≦α shown in
Therefore, if the relationship is made to be the W3>α as described above, the flow resistance against the flow from the liquid flow path 3 to the liquid supply port 5 side becomes higher than the case where the aforesaid relationship is W3≦α, hence making it possible to sufficiently suppress the flow from the liquid flow path 3 to the liquid supply port 5 side at the time of bubbling initiation for the bubble growth. Also, it becomes possible to suppress sufficiently the flow that comes from the liquid flow path 3 to the liquid supply port 5 through the gap between the movable member 8 and the circumference of the liquid supply port 5. As a result, the liquid supply port 5 can be shielded by the movable member 8 reliably and quickly. With the occurrence of these events, the discharge efficiency can be enhanced still more.
(Fifth Embodiment)
Further, for each of the embodiments described above, it is more preferable, as shown in
With the relationship thus arranged, when the movable member 8, which has been displaced upward to the liquid supply port 5 side by the bubbling initiation, begins to be displaced downward, the contact width between the leading edge of the fee end of the movable member 8 and the opening edge of the liquid supply port 6 becomes smaller. Then, the friction force generated between them is also reduced so that the liquid supply port is released priorly from free end side of the movable member. In this way, the liquid supply port is released by the movable member reliably and quickly. As a result, refilling is carried out more efficiently to stabilize the discharge characteristics still more.
Also,
The liquid discharge head shown in FIG. 20 and
(Sixth Embodiment)
For the liquid discharge head shown in
The liquid supply port 5 is arranged for the liquid flow path 3, and the common liquid supply chamber 6 is communicated with the liquid supply port 5.
Between the liquid supply port 5 and the liquid flow path 3, the movable member 8 is arranged to be substantially parallel to the opening area of the liquid supply port 5 with a minute gap α (10 μm or less, for instance). The area of the movable member 8, which is surrounded at least by the free end portion and both sides continued therefrom, is made larger than the opening area S of the liquid flow path that faces the liquid flow path, and also, a minute gap β is arranged each between the side portions of the movable member 8 and the side walls 10 of the liquid flow path. In this way, while the movable member 8 can move in the liquid flow path 3 without friction resistance, its displacement to the opening area side is regulated on the circumference of the opening area S, hence closing the liquid supply port 5 essentially to make it possible to prevent liquid flow from the liquid flow path 3 to the common liquid supply chamber 6. Also, in accordance with the present embodiment, the movable member 8 is positioned to face the elemental base plate 1. Then, one end of the movable member 8 is arranged to be the free end which can be displaced to the heat generating element 4 side of the elemental base plate 1, and the other end thereof is supported by the supporting member 9B.
Also, as in the fourth embodiment, it is preferable to arranged the relationship between the gap a between the opening edge of the liquid supply port 5 on the liquid flow path 3 side and the surface of the movable member 8 on the liquid supply port 5 side, and the overlapping width Wb of the movable member 8 in the widthwise direction, which is overlapped with the opening edge of the liquid supply port 5 on the liquid flow path 3 side, to be Wb>α for the enhancement of the discharge efficiency.
Further, as in the fifth embodiment, it is more preferable to arrange the relationship between the overlapping width Wa of the movable member 8 in the discharge port 7 direction, which is overlapped with the opening edge of the liquid supply port 5 on the liquid flow path 3 side, and the overlapping width Wb of the movable member 8 in the widthwise direction thereof to be Wb>Wa in order to stabilize the discharge characteristics.
(Seventh Embodiment)
Now, the description will be made of a base plate for use of head preferably adoptable for each of the modes described above, and a method for manufacturing a liquid discharge head as well.
The circuit and element, which are arranged to drive the heat generating elements 4 of the liquid discharge head described above, and to control the driving thereof, are provided for the elemental base plate 1 or the ceiling plate 2 in accordance with the functions that each of them should perform accordingly. Also, since the elemental base plate 1 and ceiling plate 2 are formed by silicon material for the circuit and element, it is possible to form them easily and precisely by use of the semiconductor wafer process technologies and techniques.
Now, hereunder, the description will be made of the structure of the elemental base plate 1 formed by use of the semiconductor wafer process technologies and techniques.
The films on the elemental base plate 1 are formed on the surface of a silicon base plate 201 one after another by use of semiconductor manufacturing technologies and techniques. Then, the thermoactive portion 208 is provided for the silicon base plate 201.
As shown in
The portion of the P type well region 423, which is different from that of the N-MOS 421, is provided with the N-MOS transistor 430 for driving use of the electrothermal converting element. The N-MOS transistor 430 also comprises the source region 432 and the drain region 431, which are provided locally on the surface layer of the P type well region 423 by the impurity implantation and diffusion process or the like, and the gate wiring 433 deposited on the surface portion of the P type well region 423 with the exception of the source region 432 and the drain region 431 through the gate insulation film 428, and some others.
In accordance with the present embodiment, the N-MOS transistor 430 is used as the transistor for driving use of the electrothermal converting element. However, the transistor is not necessarily limited to this one if only the transistor is capable of driving a plurality of electrothermal converting elements individually, as well as it is capable of obtaining the fine structure as described above.
Between each of the elements, such as residing between the P-MOS 420 and the N-MOS 421 or between the N-MOS 421 and the N-MOS transistor 430, the oxidation film separation area 424 is formed by means of the field oxidation in a thickness of 5,000 Å and 10,000 Å. Then, by the provision of such oxidation film separation area 424, the elements are separated from each other, respectively. The portion of the oxidation film separation area 424, that corresponds to the thermoactive portion 208, is made to function as the heat accumulating layer 434 which is the first layer, when observed from the surface side of the silicon base plate 201.
On each surface of the P-MOS 420, N-MOS 421, and N-MOS transistor 430 elements, the interlayer insulation film 436 of PSG film, BPSG film, or the like is formed by the CVD method in a thickness of approximately 7,000 Å. After the interlayer insulation film 436 is smoothed by heat treatment, the wiring is arranged using the Al electrodes 437 that become the first wiring by way of the contact through hole provided for the interlayer insulation film 436 and the get insulation film 428. On the surface of the interlayer insulation film 436 and the Al electrodes 437, the interlayer insulation film 438 of SiO2 is formed by the plasma CVD method in a thickness of 10,000 Å to 15,000 Å. On the portions of the surface of the interlayer insulation film 438, which correspond to the thermoactive portion 208 and N-MOS transistor 430, the resistive layer 204 is formed with TaN0.8.hex film by the DC sputtering method in a thickness of approximately 1,000 Å. The resistive layer 204 is electrically connected with the Al electrode 437 in the vicinity of the drain region 431 by way of the through hole formed on the interlayer insulation film 438. On the surface of the resistive layer 204, the Al wiring 205 is formed to become the second wiring for each of the electrothermal converting elements.
The protection film 206 on the surfaces of the wiring 205, the resistive layer 204, and the interlayer insulation film 438 is formed with Si3N4 film by the plasma CVD method in a thickness of 10,000 Å. The cavitation proof film 207 deposited on the surface of the protection film 206 is formed by a thin film of at least one or more amorphous alloys in a thickness of approximately 2,500 Å, which is selected from among Ta (tantlum), Fe (iron), Ni (nickel), Cr (chromium), Ge (germanium), Ru (ruthenium), and some others.
Now, with reference to
At first, in
The Al film patter 25 functions as an etching stop layer when the liquid flow paths 3 are formed by use of dry etching to be described later. This arrangement is needed because the thin film, such as Ta, that serves as the cavitation proof film 207 on the elemental base plate 1, and the SiN film that serves as the protection layer 206 on the resistive element tend to be etched by the etching gas used for the formation of the liquid flow paths 3. The Al film pattern 25 prevents these layers or films from being etched. Therefore, in order not to allow the surface of the elemental base plate 1 on the heat generating element 4 side to be exposed when the liquid flow paths 3 are dry etched, the width of each Al film pattern 25 in the direction orthogonal to the flow path direction of the liquid flow path 3 is made larger than the width of the liquid flow path 3 which is formed ultimately.
Further, at the time of dry etching, ion seed and radical are generated by the decomposition of CF4, CxFy, SF6 gas, and the heat generating elements 4 and functional elements on the elemental base plate 1 may be damaged in some cases. However, the Al film pattern 25 receives such ion seed and radical so as to protect the heat generating elements 4 and functional elements on the elemental base plate 1 from being damaged.
Then, in
Then, in
Then, in
Now, in
Then, in
Then, in
Then, in
Then, in
In continuation, as shown in the above Table 1, using the hot plate epoxy resin 31 is prebaked in condition of 90° C. for 5 minutes. After that, using the exposing device (Canon: MPA 600) the epoxy resin 31 is exposed to a specific pattern with a quantity of exposing light of 2[J/cm2]. The exposed portion of the negative type epoxy resin is hardened, while the portion which is not exposed is not hardened. Thus, in the aforesaid exposing step, only the portion that excludes the portion becoming the liquid supply port 5 is exposed. Then, using the aforesaid developer the hole portion that becomes the liquid supply port 5 is formed. After that, the regular baking is made in condition of 200° C. for one hour. The area of opening of the hole portion that becomes the liquid supply port 5 is made smaller than the area of the SiN film 29 that becomes the movable member 8.
Lastly, in
As has been described above, the ceiling plate 2 provided with the common liquid supply chamber 6 of large capacity, which is communicated with each of the liquid supply ports 5 at a time, is bonded to the elemental base plate 1 having the movable members 8, the flow path side walls 10, and liquid supply ports 5 provided therefor, hence manufacturing the liquid discharge head shown in
(Eighth Embodiment)
For the method of manufacture of the seventh embodiment described above, the description has been made of the manufacturing steps for the provision of the movable members 8, the flow path side walls 10, and the liquid supply ports 5 for the elemental base plate 1. However, the method is not necessarily limited thereto. It may be possible to adopt a process in which a ceiling plate 2 having already movable members 8 and liquid supply port 5 incorporated therein is bonded to the elemental base plate 1 having the flow path side walls 10 formed therefor.
Now, hereunder, with reference to
At first, in
Then, in
Then, in
Then,
Then, in
Lastly, in
For the member provided with the movable member 8 and the liquid supply port 5 arranged on the ceiling plate 2 side, there is further provided the common liquid supply chamber 6 of large capacity, which is communicated with each of the liquid supply ports 5 at a time. Then, to this member is bonded the elemental base plate 1 having flow path walls that form each of the liquid flow paths 3 one end of which is communicated with each discharge port 7, hence manufacturing the liquid discharge head shown in FIG. 30. The liquid discharge head of this mode, too, can demonstrate the same effect as the liquid discharge head whose structure is shown in
(Other Embodiments)
Hereinafter, the description will be made of various embodiments preferably suitable for the head that uses the principle of liquid discharge of the present invention.
(Side Shooter Type)
(Movable Member)
For each of the embodiments described above, the material that forms the movable member should be good enough if only it has resistance to solvent, as well as the elasticity that facilities the operation of the movable member in good condition.
As the material of the movable member, it is preferable to use a highly durable metal, such as silver, nickel, gold, iron, titanium, aluminum, platinum, tantalum, stainless steel, phosphor bronze, and alloys thereof; or resin of nitrile group, such as acrylonitrile, butadiene, styrene; resin of amide group, such as polyamide; resin of carboxyl group, such as polycarbonate; resin of aldehyde group, such as polyacetal; resin of sulfone group, such as polysulfone; and liquid crystal polymer or other resin and the compounds thereof; a highly ink resistive metal, such as gold, tungsten, tantalum, nickel, stainless steel, titanium; and regarding the alloys thereof and resistance to ink, those having any one of them coated on the surface thereof or resin of amide group, such as polyamide, resin of aldehyde group, such as polyacetal, resin of ketone group, such as polyether etherketone, resin of imide group, such as polyimide, hydropxyl group, such as phenol resin, resin of ethyl group, such as polyethylene, resin of alkyl group, such as polypropylene, resin of epoxy group, such as epoxy resin, resin of amino group, such as melamine resin, resin of methyrol group, such as xylene resin and the compound thereof; further, ceramics of silicon dioxide, silicon nitride, or the like, and the compound thereof. Here, the target thickness of the movable member of the present invention is of μm order.
Now, the arrangement relations between the heat generating member and movable member will be described. With the optimal arrangement of the heat generating element and the movable member, it becomes possible to control and utilize the liquid flow appropriately when bubbling is effected by use of the heat generating element.
For the conventional art of the so-called bubble jet recording method, that is, an ink jet recording method whereby to apply heat or other energy to ink to create change of states in it, which is accompanied by the abrupt voluminal changes (creation of bubble), and then, use of the acting force based upon this change of states, ink is discharged from the discharge port to a recording medium for the formation of images thereon by the adhesion of ink thus discharged, the area of the heat generating element and the discharge amount of ink maintain the proportional relationship as indicated by slanted lines in FIG. 32. However, it is readily understandable that there exists the region S which effectuates no bubbling, which does not contribute to discharging ink. Also, from the burning condition on the heat generating element, this region S in which no bubbling is effected exists on the circumference of the heat generating element. With these results in view, it is assumed that the circumference of the heat generating element in a width of approximately 4 μm does not participate in bubbling. On the other hand, for the liquid discharge head of the present invention, the liquid flow path that includes the bubble generating means is essentially covered with the exception of the discharge port so that the maximum discharge amount is regulated. Therefore, as indicated by a solid line in
(Elemental Base Plate)
Hereunder, the description will be made of the structure of the elemental base plate 1 provided with the heat generating elements 10 for giving heat to liquid.
On an elemental base plate 1, a ceiling plate 2 is arranged, and each liquid flow path 3 is formed between the elemental base plate 1 and the ceiling plate 2.
For the elemental base plate 1, silicon oxide film or silicon nitride film 106 is filmed on a substrate 107 of silicon or the like for the purpose of making insulation and heat accumulation. On this film, there are pattered as shown in
The pressure and shock waves become intensified at the time of bubbling or bubbling extinction, in particular, which may cause the durability of the hard and brittle oxide films to be lowered significantly. To counteract this, a metallic material, such as tantalum (Ta), is used as the cavitation proof layer 102.
Also, by the combination of liquid, the flow path structure, and resistive materials, it may be possible to arrange a structure which does not need the protection film 103 for the aforesaid resistive layer 105. The example of such structure is shown in FIG. 33B. An alloy of iridium-tantalum-aluminum may be cited as a material of the resistive layer 105 that requires no protection film 103.
As described above, it may be possible to arrange only the resistive layer 105 (heat generating portion) between the electrodes 104 to form the structure of the heat generating element 4 for each of the embodiments described earlier. Here, also, it may be possible to arrange the structure so that a protection film 103 is included for the protection of the resistive layer 105.
For each of the embodiments, the structure is arranged with the heat generating portion formed by the resistive layer 105 which generates heat as the heat generating element 4 in accordance with electric signals, but the heat generating element is not necessarily limited thereto. Any heat generating element may be adoptable if only it can create bubble in bubbling liquid sufficiently so as to discharge discharging liquid. For example, such element may be an opto-thermal converting member that generates heat when receiving laser or some other light or the member which is provided with a heat generating portion that generates heat when receiving high frequency.
In this respect, on the aforesaid elemental base plate 1, functional devices, such as transistors, diodes, latches, shift registers, and others, which are needed to drive the heat generating elements 4 (electrothermal converting elements) selectively, may be integrally incorporated by use of the semiconductor manufacturing processes, besides the resistive layer 105 that constitutes the heat generating portion, and each heat generating element 4 formed by the wiring electrodes 104 to supply electric signals to the resistive layer 105.
Also, in order to discharge liquid by driving the heat generating portion of each heat generating element 4 installed on the aforesaid elemental base plate 1, such rectangular pulses as shown in
(Discharging Liquid)
Of such liquids as described earlier, it is possible to use ink having the same compositions as the one used for the conventional bubble jet apparatus as liquid usable for recording (recording liquid).
However, as the characteristics of discharging liquid, it is desirable to use the one which does not impede discharging, bubbling, or the operation of movable member by itself.
As the discharging liquid for recording use, highly viscous ink or the like can be used, too.
Further, for the present invention, ink of the following composition is used as the recording liquid that can be adopted as discharging liquid. However, with the enhanced discharging power which in turn makes ink discharge speed faster, the displacement accuracy of liquid droplets is improved to obtain recorded images in extremely fine quality.
(Liquid Discharge Apparatus)
Photocouplers 611 and 612 are arranged in the vicinity of one end of the lead screw 605. The photocouplers 611 and 612 are the means for detecting home position which switches the rotational directions of the driving motor 602 by recognizing the presence of the lever 607a of the carriage 607 in the effective region of the photocouplers 611 and 612. In the vicinity of one end of the platen 609, a supporting member 613 is arranged for supporting the cap member 614 that covers the front end having the discharge ports of the head cartridge 601. Also, there is arranged the ink suction means 615 that sucks ink retained in the interior of the cap member 614 when idle discharges or the like are made from the head cartridge 601. With the ink suction means 615, suction recoveries of the head cartridge 601 are performed through the opening portion of the cap member 614.
For the ink jet recording apparatus 600, a main body supporting member 619 is provided. For this main body supporting member 619, a movable member 618 is movably supported in the forward and backward directions, that is, the direction at right angles to the traveling directions of the carriage 607. On the movable member 618, a cleaning blade 617 is installed. The mode of the cleaning blade 617 is not necessarily limited to this arrangement. Any known cleaning blade of some other modes may be applicable. Further, there is provided the lever 620 which initiates suction when the ink suction means 615 operates its suction recovery. The lever 620 moves along the movement of the cam 621 that engages with the carriage 607. The movement thereof is controlled by known transmission means such as the clutch that switches the driving power of the driving motor 602. The ink jet recording controller, which deals with the supply of signals to the heat generating elements provided for the head cartridge 601, as well as the driving controls of each of the mechanisms described earlier, is provided for the recording apparatus main body side, and not shown in FIG. 35.
For the ink jet recording apparatus 600 structured as described above, the aforesaid recording medium carrying means carries a printing sheet P on the platen 609, and the head cartridge 601 reciprocates over the entire width of the printing sheet P. During this reciprocation, when driving signals are supplied to the head cartridge 601 from driving signal supply means (not shown), ink (recording liquid) is discharged from the liquid discharge head unit to the recording medium in accordance with the driving signals for recording.
The recording apparatus receives printing information from a host computer 300 as control signals. The printing information is provisionally stored on the input interface 301 in the interior of a printing apparatus, and at the same time, converted into the data processible in the recording apparatus, thus being inputted into the CPU (central processing unit) 302 that dually functions as head driving signal supply means. The CPU 302 processes the data thus received by the CPU 302 using RAM (random access memory) 304 and other peripheral units in accordance with the control program stored on ROM (read only memory), and convert them into the data (image data) for printing.
Also, the CPU 302 produces the driving data which are used for driving the driving motor 602 for carrying the recording sheet and the carriage 607 to travel together with the head cartridge 601 mounted thereon in synchronism with image data in order to record the image data on appropriate positions on the recording sheet. The image data and the motor driving data are transmitted to the head cartridge 601 and the driving motor 602 through the head driver 307 and motor driver 305, respectively. These are driven at controlled timing, respectively, to form images.
For the recording medium 150 which is used for a recording apparatus of the kind for the adhesion of liquid, such as ink, thereon, it is possible to use, as an objective medium, various kinds of paper and OHP sheets; plastic materials used for a compact disc, ornamental board, and the like; cloths; metallic materials, such as aluminum, copper; leather materials, such as cowhide, pigskin, and artificial leathers; wood materials, such as wood, plywood; bamboo materials; ceramic materials, such as tiles; and three-dimensional structure, such as sponge, among some others.
Also, as the recording apparatus hereof, the followings are included: a printing apparatus for recording on various kinds of paper, OHP sheet, and the like; a recording apparatus for use of plastic materials which records on a compact disc, and other plastic materials; a recording apparatus for use of metallic materials that records on metallic plates; a recording apparatus for use of leather materials that records on leathers; a recording apparatus for use of wood materials that records on woods; a recording apparatus for use of ceramics that records on ceramic materials; and a recording apparatus for recording a three-dimensional netting structures, such as sponge. Also, a textile printing apparatus or the like that records on cloths is included therein.
Also, as discharging liquid usable for any one of these liquid discharge apparatuses, it should be good enough if only such liquid can be used matching with the respective recording mediums and recording conditions accordingly.
| Number | Date | Country | Kind |
|---|---|---|---|
| 11-250935 | Sep 1999 | JP | national |
| 2000-037125 | Feb 2000 | JP | national |
This is a divisional application of application Ser. No. 10/255,833, filed on Sep. 27, 2002 now U.S. Pat. No. 6,854,831, which is a divisional application of application Ser. No. 09/651,558, filed on Aug. 31, 2000, now issued as U.S. Pat. No. 6,497,475.
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| Number | Date | Country | |
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| 20050052503 A1 | Mar 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10255833 | Sep 2002 | US |
| Child | 10965824 | US | |
| Parent | 09651558 | Aug 2000 | US |
| Child | 10255833 | US |
