Manufacturing method for ink jet recording head

Abstract: A manufacturing method for an ink jet recording head comprising ink ejection outlets, ink passages (30) in fluid communication with the ink ejection outlets, an ink chamber (12) for supplying ink to the ink passages (30), energy generating elements for ejecting ink, a grooved top plate having ink passage walls, an ink chamber frame for defining the ink passages (30) and the ink chamber and the ink ejection outlets, a substrate for supporting the energy generating elements, wherein the ink passages (30) and ink chamber (12) are formed by coupling the grooved top plate and the substrate, the improvement residing in that the grooved top plate is molded, and after the molding, a laser machining is effected to a neighbourhood of a connecting portion between the ink chamber frame and a passage wall.

Description: The present invention relates to a manufacturing method for an ink jet recording head according to the preamble clause of claim 1, and to an ink jet recording head according to the preamble clause of claim 8. Such a method and recording head are known from US-A-4 723 129. Ink jet recording heads of various structures, usable with an ink jet recording apparatus in which an image is formed by ejecting ink droplets onto a recording material, are commercially available. An example of such an ink jet recording head is shown in Figure 2 as an exploded perspective view. Figure 3 is a sectional view taken along an ink passage of an ink jet recording head. On a silicon substrate, there are provided energy generating elements (not shown) for generating energy for ejecting the ink. The silicon substrate 1 is bonded with a bonding material 4 having a high thermal conductivity, on an aluminum plate 27 to promote heat radiation from the silicon substrate 1. An orifice plate 23 is provided with ejection outlets 14 for ejecting the ink and is integral with a top plate 11 having recesses to constitute a liquid chamber 12 for containing ink to be supplied to the ejection outlets 14 and ink passages 28 for fluid communication between the liquid chamber 12 and the ejection outlets 14. The top plate 11 is provided with an ink supply port 10 in fluid communication with the recess to constitute the liquid chamber 12. Through the supply port 10, the ink is supplied to the liquid chamber 12 from the outside of the recording head. The top plate 11 is coupled with substrate 1 so that the energy generating elements and the ink passages 28 correspond with each other, respectively, and the top plate 11 and the substrate 1 are fixed by a confining spring 26, thus constituting the ink passages 28 and the liquid chamber 12. Figure 1 is an enlarged schematic view of the top plate 11. As described above, the top plate 11 is integral with an orifice plate 28 having ejection outlets 14 and recesses for constituting the liquid passages and the liquid chamber 12. The top plate has been produced through ejection molding or another molding process since such processes are convenient for mass-production with low cost. As regards the ejection outlets, the manufacturing accuracy through the molding is not enough, and therefore, they are formed using excimer laser as disclosed in U.S. Patent No. 5,208,604. The top plate is produced by injection molding or the like by using female mold, and therefore, the configuration of the mold at portions corresponding to the ink passages is female configuration of the ink passage, and the same applies to the liquid or ink chamber. Referring to Figures 4 and 5, the description will be made as to the mold for injecting molding the top plate 11. Figure 4 is a sectional view of a mold for the top plate, taken along the ink passage, and Figure 5 is a perspective view of a block for forming the ink passages. The metal comprises a block 73 for forming the liquid chamber and a block 71 for forming the ink passages 28. At the end of the block 71, an array of grooves 72 corresponding to the ink passages 28, is formed. Above the block 71 for forming the ink passages 28, there is a cavity 64 for forming the top plate 11. Into the block 73 for forming the common liquid chamber, a nest pin 65 for forming the ink supply port is inserted. Designated by 61, 62, 63 and 66, are injector pins for a runner, gate, runner injector pin and orifice plate. The female portions corresponding to the ink passages (block 71), has a plurality of grooves arranged at the interval of 70.5 µm, for a recording head of 360 dpi resolution, for example, and therefore, the accuracy in the order of microns is required. For this reason, machining is used. On the other hand, the female portion (block 73) corresponding to the ink chamber has to be formed by electric discharge machining or the like to realize three dimensional configuration to meet the design requirement as the recording head. In view of these factors, as for the metal mold for forming the top plate, the block is processed through proper method in consideration of the accuracy and the configuration required for each part of the mold, and the entire metal mold is provided by combining them (Figure 4). In the above-described ink jet head, the respective ink passage walls of the top plate and the ink chamber wall are closely contacted to the substrate to form the ink passage spaces and ink chamber space, and therefore, for the metal mold for forming the top plate, the accuracy of assembling the block 71 for forming the ink passage and the block 73 for forming the ink chamber, necessarily requires high accuracy so as to prevent formation of step at the ink passage wall and the ink chamber wall. The accuracy includes the manufacturing accuracy of the blocks themselves, and in addition, the assembling accuracy in Z direction and surface alignment accuracy in X direction are also important with the result of necessities for assembling skill, measurement skill, consideration to simulation to deviation upon temperature rise of the metal mold. With such conventional method, contact surfaces between blocks 71 and 73 may be with flashes, depending on the finishing accuracy or arrangement accuracy. If the top plate has the flash, which is projected beyond the ink passage wall surface, the ink passage walls are not sufficiently closely contacted to the base plate, and therefore, when the ink is ejected, a pressure wave is transmitted to an adjacent nozzle or nozzles with the result of instability of ink ejection (cross-talk). Additionally, even if there is no problem with the initial state of the mold, damage can be given by ejection pressure with continued molding operation, with the result that the flashes are produced. Particularly, in the case that ink liquid chambers for respective colors are integrally molded to permit low cost color recording, the tendency of flash production increases corresponding to the larger number of ink chamber frames. SUMMARY OF THE INVENTION Accordingly, it is a principal object of the present invention to provide an ink jet recording head and a manufacturing method therefor, wherein ink jet recording heads can be manufactured with high accuracy and with high yield at low cost, and both the reliability of such recording heads and the recording resolution are high (high recording resolution implies that the ejection outlets are arranged at high density). In particular, also care should be taken that the method allows a manufacturing of ink jet recording heads substantially free of cross-talk, without the necessity for increasing the assembling method of the metal mold even if a continuous molding operation is carried out. According to the present invention this object is attained with the characterizing clause of claim 1 concerning the method and with the characterizing clause of claim 8 concerning the recording head. Advantageous embodiments of the method are the subject matter of claims 2 to 7. According to the present invention, it is possible to essentially solve the manufacturing, assembling and/or cost problems usually existing for the metal mold, by a processing with the laser at the portion where the ink passage wall and the ink chamber frame are contacted. Further, it is also possible that the laser processing can be carried out simultaneously with formation of ejection outlets in the orifice plate. In addition to the easing of the required accuracy of the assembling of the metal mold at the initial stage, the maintenance of the step state can be eased after the metal mold is used, so that metal mold maintenance is unnecessary in this respect and the productivity is improved. The present invention is particularly suitable in an ink jet recording head and recording apparatus wherein thermal energy by an electrothermal transducer, laser beam or the like is used to cause a change of state of the ink to eject or discharge the ink. This is because the high density of the picture elements and the high resolution of the recording are possible. The typical structure and the operational principle are preferably the ones disclosed in U.S. Patent Nos. 4,723,129 and 4,740,796. The principle and structure are applicable to a so-called on-demand type recording system and a continuous type recording system. Particularly, however, it is suitable for the on-demand type because the principle is such that at least one driving signal is applied to an electrothermal transducer disposed on a liquid (ink) retaining sheet or liquid passage, the driving signal being enough to provide such a quick temperature rise beyond a departure from nucleation boiling point, by which the thermal energy is provided by the electrothermal transducer to produce film boiling on the heating portion of the recording head, whereby a bubble can be formed in the liquid (ink) corresponding to each of the driving signals. By the production, development and contraction of the the bubble, the liquid (ink) is ejected through an ejection outlet to produce at least one droplet. The driving signal is preferably in the form of a pulse, because the development and contraction of the bubble can be effected instantaneously, and therefore, the liquid (ink) is ejected with quick response. The driving signal in the form of the pulse is preferably such as disclosed in U.S. Patents Nos. 4,463,359 and 4,345,262. In addition, the temperature increasing rate of the heating surface is preferably such as disclosed in U.S. Patent No. 4,313,124. The structure of the recording head may be as shown in U.S. Patent Nos. 4,558,333 and 4,459,600 wherein the heating portion is disposed at a bent portion, as well as the structure of the combination of the ejection outlet, liquid passage and the electrothermal transducer as disclosed in the above-mentioned patents. In addition, the present invention is applicable to the structure disclosed in Japanese Laid-Open Patent Application No. 123670/1984 wherein a common slit is used as the ejection outlet for plural electrothermal transducers, and to the structure disclosed in Japanese Laid-Open Patent Application No. 138461/1984 wherein an opening for absorbing pressure wave of the thermal energy is formed corresponding to the ejecting portion. This is because the present invention is effective to perform the recording operation with certainty and at high efficiency irrespective of the type of the recording head. The present invention is effectively applicable to a so-called full-line type recording head having a length corresponding to the maximum recording width. Such a recording head may comprise a single recording head and plural recording head combined to cover the maximum width. In addition, the present invention is applicable to a serial type recording head wherein the recording head is fixed on the main assembly, to a replaceable chip type recording head which is connected electrically with the main apparatus and can be supplied with the ink when it is mounted in the main assembly, or to a cartridge type recording head having an integral ink container. The provisions of the recovery means and/or the auxiliary means for the preliminary operation are preferable, because they can further stabilize the effects of the present invention. As for such means, there are capping means for the recording head, cleaning means therefor, pressing or sucking means, preliminary heating means which may be the electrothermal transducer, an additional heating element or a combination thereof. Also, means for effecting preliminary ejection (not for the recording operation) can stabilize the recording operation. As regards the variation of the recording head mountable, it may be a single corresponding to a single color ink, or may be plural corresponding to the plurality of ink materials having different recording color or density. The present invention is effectively applicable to an apparatus having at least one of a monochromatic mode mainly with black, a multi-color mode with different color ink materials and/or a full-color mode using the mixture of the colors, which may be an integrally formed recording unit or a combination of plural recording heads. Furthermore, the ink is usually liquid. It may be, however, an ink material which is solidified below the room temperature but liquefied at the room temperature. Since the ink is controlled within the temperature not lower than 30 o C and not higher than 70 o C to stabilize the viscosity of the ink to provide the stabilized ejection in usual recording apparatus of this type, the ink may be such that it is liquid within the temperature range when the recording signal is the present invention is applicable to other types of ink. In one of them, the temperature rise due to the thermal energy is positively prevented by consuming it for the state change of the ink from the solid state to the liquid state. Another ink material is solidified when it is left, to prevent the evaporation of the ink. In either of the cases, the application of the recording signal producing thermal energy, the ink is liquefied, and the liquefied ink may be ejected. Another ink material may start to be solidified at the time when it reaches the recording material. The present invention is also applicable to such an ink material as is liquefied by the application of the thermal energy. Such an ink material may be retained as a liquid or solid material in through holes or recesses formed in a porous sheet as disclosed in Japanese Laid-Open Patent Application No. 56847/1979 and Japanese Laid-Open Patent Application No. 71260/1985. The sheet is faced to the electrothermal transducers. The most effective one for the ink materials described above is the film boiling system. The ink jet recording apparatus may be used as an output terminal of an information processing apparatus such as computer or the like, as a copying apparatus combined with an image reader or the like, or as a facsimile machine having information sending and receiving functions. These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an enlarged schematic view of a top plate. Figure 2 is a exploded perspective view of an example of an ink jet recording head. Figure 3 is a sectional view of an ink jet recording head taken along an ink passage. Figure 4 is a sectional view of a metal mold for injection molding of a top plate, taken along an ink passage. Figure 5 is a perspective view of a block for forming ink passage array. Figure 6, (a) is a sectional view of an ejecting element illustrating forward step between the ink passage array and the ink chamber frame. Figure 6, (b) is a sectional view of an ejecting element illustrating reverse step between the ink passage array and the ink chamber. Figure 7 is a perspective view of a top plate used in Embodiments 1 and 3 of the present invention. Figure 8 is a perspective view of a part illustrating before and after flash removal in Embodiment 1 of the present invention. Figure 9 is a perspective view of a top plate having a plurality of ink chambers according to Embodiment 2 of the present invention. Figure 10 is a perspective view illustrating the state before flash removal on the plurality of ink chamber frames, according to Embodiment 2 of the present invention. Figure 11 is a perspective view illustrating states before and after removal of the reverse step, according to Embodiment 3 of the present invention. Figure 12 illustrates a mask for laser machining according to Embodiment 3 of the present invention. Figure 13 illustrates a shutter for controlling a laser application period for the correction of the reverse step, according to Embodiment 3 of the present invention. Figure 14 illustrates a structure used in Embodiment 3. Figure 15 illustrates an excimer laser machining apparatus according to an embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Figure 6, (a), (b) illustrate conventional examples. Figure 8, (b) illustrates a feature of the present invention, and Figures 7, 8, (a), (b) generally illustrate a top plate used in this embodiment. In the description of this embodiment, an ink jet recording head is provided with 2 or 5 ink ejection outlets, but the present invention is applicable to a high density multi-array ink jet recording head having a larger number of ejection outlets. The present invention is applicable also to a recording head integrally having ink passages ejecting different volumes of ink droplets. An example thereof has 64 black ink nozzle ejecting 80 ng ink droplet, and 24 nozzles for each of yellow, magenta and cyan inks capable of ejecting 40 ng ejection volume on a line, for 360 dpi printing (Embodiment 2). The substrate 1 is of a silicone wafer having a thickness of 0.625 mm. On the substrate 1, heat generating resistors of HfB 2 , and wiring and electrode (material A1) for the heat generating resistors, are formed in this order by a sputtering machine. Thereafter, patterning is carried out through the process similar to a semiconductor manufacturing process, including photosensitive resist application, pattern exposure, development and resist removal. By doing so, electrothermal transducer element constituted by the heat generating resistors, wiring and electrodes, are formed on the same side of the substrate at predetermined regular intervals. For the purpose of improvement in the durability, various function layers such as electrically insulative film of SiO 2 , protection film of Ta, electrode oxidation preventing film Au or the like, are formed. Subsequently, blocks 71, 73, 74, 75 or the like having a plurality of grooves as shown in Figure 5, are set in the metal mold to provide a cavity 64 (Figure 4), and then, the resin material is injected into the cavity 64, using injection molder. Thereafter, the molded material is taken out, and it is subjected to a gate process, thus producing a top plate 11. Here, the use is made with polysulfone as the resin material having plastization temperature of approx. 400 o C with metal mold temperature of approx. 150 °C. The top plate 11 thus produced has an array 30 of ink passages at 70.5 µm intervals. Between a surface of the ink passage wall 29 to be contacted with the substrate 1 and a surface of the ink chamber frame 13, there is a proper forward step 55, more particularly, the ink passage wall is higher than the ink chamber frame by approx. 5 µm. However, there is a small gap between the block 71 for providing the array 30 of the ink passages and the block 73 for providing the ink chamber or the like, the gap being inevitable to permit setting of the blocks, and therefore, a flash 51 having a height of approx. 10 µm is produced (Figure 8, (a)). When the ink ejection element is assembled using such a top plate, the ink passage wall is not sufficiently closely contacted to the substrate 1 due to the projected flash beyond the ink passage wall surface. If this occurs, the problem in the printing arises (such as cross-talk). In this Embodiment 1, an excimer laser beam is projected to the contacting and crossing portion between the ink passage wall 29 and the ink chamber frame 13 of the top plate 11, thus removing the flash through abrasion. The processing or machining is schematically shown in Figures 8, (a) and (b), where the portion designated by a reference numeral 53 is the portion illuminated by an excimer laser, where the flash is removed. The structure of the excimer laser machining apparatus is as shown in Figure 15, in which a reference numeral 31 designates an excimer laser beam, 32 is a main assembly of the excimer laser apparatus, 33 is a half mirror and a power meter for monitoring the power of the laser, 34 is an optical lens system for projecting the excimer laser beam, corresponding to the ejection outlet pattern, 35 is a mask having a pattern of the flash removing portions, 36 is a work piece moving and supporting table, 37 is an observation system for image processing, and 38 is a control system for controlling a laser oscillation timing or work piece positioning or the like. As for the machining conditions, KrF excimer laser (wavelength of 248 nm) beam is projected at an angle of 45 degrees relative to the surface of the ink chamber frame, at the repetition frequency of 100 pps and with the pulse energy density of 600 mJ/cm 2 . With these conditions, the flash 51 having a height of approx. 10 µm was removed by 50 pulses. By the abrasion processing, some sub-products are deposited, which, however, could be reduced by blowing helium gas simultaneously with the abrasion. Subsequently, the orifice plate 23 of the top plate 11 is ink ejection outlet formation by application of ink repelling material and using excimer laser. As shown in Figure 2, the substrate 1 is die-bonded on the base plate 27. The processed top plate 11 is aligned so that the ink passages 28 and the ink ejection energy generating elements (not shown) correspond to each other, respectively. Then, they are fixed by a confining spring 26. Although not shown in Figure 2, a silicon sealant, TSE 399 (3000 cps) available from Toshiba Silicone Kabushiki Kaisha, Japan is applied to the connecting region or the like between the ink chamber frame 13 and the substrate 1, and thereafter, a barrier for the ink to be supplied to the ink chamber is formed. Using the ejection elements of the recording head thus produced, electric connection through wire bonding or the like and ink supply system connection, are carried out. Then, the ejection performance test and printing durability test are carried out, after it is assembled into a printer. Since the flashes are removed before assembled into a recording head, and therefore, the shot position accuracy and dot diameters of the ejected droplet, are satisfactory to meet the design requirements, and therefore, the reliability is high. In the conventional example, the gap is formed between the blocks 71 and 73 in the metal mold for the formation of the top plate with the result of production of the flash in the molded top plate. This leads to improper printing. Therefore, maintenance operations for the metal mold (adjustments of surfaces of the blocks and reassembling and adjustment), are required. According to the present invention, however, the proper manufacturing is established without consideration to the production of the flashes. Additionally, according to this invention, the excimer laser is projected to the neighborhood of the flashes, and therefore, the unintended portion is also engraved, but the depth thereof is approx. 5 µm. This does not give rise to the problem that the sealant enters the ink passages, since the silicone sealant is permitted to enter the ink passages only if the gap is 10 - 30 µm approximately. In this embodiment, the abrasion machining is carried out using excimer laser. Depending on the structure of the top plate or the position or size of the flashes to be removed, it may be YAG laser or the like. Embodiment 2 Figures 9 and 10 illustrate Embodiment 2. A top plate 11 for four integral 360 dpi recording head (Figure 9) is produced through the injection molding process similar to Embodiment 1. The recording head includes, as a unit, a plurality ink chambers, 64 black ink nozzles of 80 ng ejection volume, 24 nozzles of 40 ng ejection volume for each of yellow, magenta and cyan colors, and 8 dummy nozzles between adjacent color nozzles. As for the forming method of the top plate integrally having the ink passage, the ink chamber or the like, the method is not necessarily limited to the injection molding, but may be cast molding method or transfer molding method using a similar metal mold. The top plate of this embodiment has four different ink chambers as shown in Figure 9, and therefore, it has respective liquid chamber frames 85, 86, 87 and 88. Similarly to Embodiment 1, the flash tends to occur between the contact surfaces between the block 71 and the block 73, that is, the crossing or contacting surfaces between the ink chamber wall and the ink passage wall in the top plate. In the case of the top plate having a plurality of ink chambers, the advantageous effects of the removal of the flashes were confirmed, for the same reasons as with Embodiment 1. Embodiment 3 Figure 14 illustrates Embodiment 3. Using the metal mold of Embodiment 1, 10,000 shot molding operations are continuously carried out, and it has been found that the block 71 is deviated relative to the block 73 by the ejection pressure damage during the continuous molding operation, with the result (Fig. 11a) that the height of the ink chamber frame 13 of the molded top plate 11 is higher than the ink passage walls (so-called reverse step). As has been described with Figure 6, (a), the ink passage walls 29 can be sufficiently closely contacted to the substrate 1 by the plastic deformation of the ink liquid chamber by the pressure of the confining spring, but the close contactness is not maintained in the case of the reverse step. This is because, the length of the ink chamber is at least several mm, but the length of the ink passage is one tenth approximately. Even if the ejection element is manufactured using such a top plate, the insufficient close contact is established between the ink passage wall 29 and the substrate 1 as shown in Figure 6, (b), and therefore, satisfactory ejection performance can be provided. In this embodiment, the machining using laser is effected on the molded top plate having the reverse step. This correction machining is carried out simultaneously with the excimer laser machining for forming ink ejection outlets on an orifice plate portion of the top plate. The top plate 11 is subjected to the excimer laser at the reverse stepped portions so that a triangular cross-section part as shown in Figure 14 is removed. The laser projection is carried out at an angle of 10 degrees relative to the surface of the ink chamber frame 13 the angle being the same as when the ejection outlets are formed. The laser mask is as shown in Figure 12. The ink ejection outlets 40 are through outlets, but the flash removing machining is partial removal, and therefore, the number of pulses required for the correction is smaller than the number of pulses projected for the ink ejection outlet formation. Therefore, a shutter 42 is provided to cover the portions to be corrected during the laser projection so as to control the number of pulses applied to the portion to be corrected depending on the time period of the opening state of the shutter after the laser beam is emitted (Figure 13). Here, the description is made as to the case of the reverse step, but the same method can be used for the removal of the flash. The range of the laser projection without movement of the top plate relative to the laser beam, is different depending on the beam size of the laser beam source, the energy density required for the machining, the optical system used or the like. However, from the standpoint of the productivity, it is preferable that the machining is completed without movement of the top plate and within the laser beam projection period for the ink ejection outlet formation. Therefore, the investigations have been made as to how much the reverse step is to be removed to satisfy the sufficient close contact between the ink passage walls 29 and the substrate 1 after the mounting of the confining spring, to satisfy the required ink ejection performance and to prevent the sealant from entering the ink chamber in the sealing material application process. It has been found that within the range of 100 - 600 µm of the ink passage length which is realistic in ink jet recording heads, if the triangular cross-sectional portion in the range not less than 20 times the height of the reverse step, is removed, the ink passage walls 29, the ink chamber frame after the correcting machining, and uncorrected portions of the ink chamber frame, are all sufficiently closely contacted to the substrate 1. According to Embodiments 1 - 3, the machining accuracies of the blocks set in the metal mold can be eased in a top plate integrally having ink passages or the like and to be formed through injection molding or cast molding or the like. Additionally, using the laser machining, the recording head manufacturing can be accomplished properly both at the initial stage having high positional accuracy and upon stepwise deviation during continuous formation. By this, the initial cost of the metal mold can be reduced, and the maintenance cost can be reduced, and the productivity reduction due to the maintenance can be avoided. By the simultaneous machining with the ink ejection outlet formation, the machining operations are carried out on the basis of one positioning and during the same period, so that the cost increase is not required. Thus, the productivity improvement and cost reduction is possible in the ink jet recording head manufacturing. As described in hereinbefore, the sub-product during the abrasion machining with the excimer laser beam is not a problem, and therefore, the helium gas is not necessarily used as in Embodiment 1. According to the present invention, the recording head can be manufactured with high yield, high productivity, high accuracy and low cost. Therefore, the advantages of the present invention are particularly remarkable for a recording head of an ink jet recording type in which the ink droplets are ejected using thermal energy, wherein the ink ejection energy generating elements are integrally formed on the substrate. The present invention is not limited to a monochromatic (black) recording head, but it is applicable to color recording heads. The present invention is neither limited to a serial scan type recording head, but is applicable to a so-called full-line type recording head covering a maximum recording width of the recording material. The ink is not limitedly liquid, but may be an ink which is solid, but is liquefied or softened upon ink ejection. The color recording head or full-line type recording head may be constituted by combining a plurality of recording heads, or may be the one integrally formed. While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the scope of the following claims.

Claims: A manufacturing method for an ink jet recording head comprising ink ejection outlets (14), ink passages (28) in fluid communication with the ink ejection outlets (14), an ink chamber (12) for supplying ink to the ink passages (28), - energy generating elements for ejecting ink, a grooved outlet plate (11) having ink passage walls (29), an ink chamber frame (13) and said ink ejection outlets (14), a substrate (1) for supporting the energy generating elements, wherein the ink passages (28) and ink chamber (12) are formed by coupling the grooved outlet plate (11) and the substrate (1), and the grooved outlet plate (11) is molded in a mold, characterized in that, after the molding step, laser machining is effected to a connection portion between the ink chamber frame (13) and a block (30) containing said ink passage walls (29) so as to remove any flash (51) or step (56) at this connecting portion due to a gap between adjacent sections (71, 73) of the mold, which gap permits setting of said mold sections (71, 73) providing said ink chamber frame (13) and said block (30), with the provision that the laser beam is projected at an angle relative to the surface of said ink chamber frame (13) so that a triangular cross-section part (56) is removed from said connection portion defined by a laser machining length (L) not less than 20 times the height (h) of said triangular cross-section part (56). A method according to claim 1, wherein said laser machining is effected to satisfy L ≥ 20 x h, where h is the height of a reverse step (56) formed at said connecting portion, and L is the laser machining length (Fig. 14). A method according to claim 1 or 2, wherein the laser is an excimer laser. A method according to claim 1, 2 or 3, wherein the laser machining is also used to substantially simultaneously form the ink ejection outlets. A method according to claim 4, wherein a mask having a first mask pattern for the laser machining for the neighborhood of the connecting portion between the ink chamber frame and the grooved outlet plate, as well as a second mask pattern for the formation of the ink ejection outlets, and wherein said first mask pattern is closed and opened by a shutter. A method according to any one of claims 1 to 5, wherein said molding is an injection molding. A method according to any one of claims 1 to 6, wherein said energy generating elements are electrothermal transducer elements. An ink jet recording head comprising ink ejection outlets (14), ink passages (28) in fluid communication with the ink ejection outlets (14), an ink chamber (12) for supplying ink to the ink passages (28), energy generating elements for ejecting ink, a grooved outlet plate (11) having ink passage walls (29), an ink chamber frame (13) and said ink ejection outlets (14), a substrate (1) for supporting the energy generating elements, wherein the ink passages (28) and ink chamber (12) are formed by coupling the grooved outlet plate (11) and the substrate (1), and the grooved outlet plate (11) is molded in a mold, characterized in that, a connection portion between the ink chamber frame (13) and a block (30) containing said ink passage walls (29) and comprising an inclined surface area (at 53) machined by a laser beam after molding to remove any flash (51) or step (56) at this connecting portion due to a gap between adjacent sections (71, 73) of the used mold, which gap permits setting of said mold sections (71, 73) providing said ink chamber frame (13) and said block (30), wherein the inclination of said inclined surface area (at 53) is defined by a triangular cross-section part (56) removed from said connection portion defined by a laser machining length (L) not less than 20 times the height (h) of said triangular cross-section part (56).

Inventors: YAMAMOTO HAJIME, YAMAMOTO, HAJIME, YAMAMOTO, HAJIME, C/O CANON K.K.
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1995
Main classification: B41J2
IPC codes: B41J2