Process for producing an ink jet recording head

Abstract: An ink jet recording head is produced by forming in a first substrate (308) a plurality of orifices (317) for ejecting an ink droplet and a reference object for registration; forming in a second substrate (307) ejection energy generating elements (315) for supplying energy for ejecting the ink placed in liquid passages (314) communicating with the orifices (317); and joining the first substrate 308 and the second substrate (307) together on the basis of the reference object for registration.

Description: The present invention relates to a process for producing an ink jet recording head according to the preamble of claim 1. Ink jet recording is a non-impact recording method which is almost free from noise generation during recording which is capable of high-speed recording and which enables to perform recording without requiring any special operations for fixing onto an ordinary paper. Of the currently known various recording methods, this method is very useful. Wide varieties of proposals have been put forward for this method and improvements have been applied to it. These efforts have led to some commercially available products, whereas some ideas are still on the way to commercialization. Ink jet recording method is one in which ink droplets are ejected by various mechanisms and are deposited it on a recording medium such as a paper, so as to perform recording. The applicant of the present invention has also made a proposal on a novel method related to an ink jet recording. This novel method was proposed in Japanese Patent Application Laying-open No. 118798/1977, and its fundamental principle is outlined as follows: Thermal pulses as information signals are applied to the ink introduced in an ink passage that can accommodate the ink. As a result, the ink generates a vapor bubble and produces an actuating force during its growth and contraction. This force causes the ink to be ejected as the droplets from orifices communicating with the ink passage, whereafter the droplets are deposited on a recording medium to perform recording. This method provides the orifices in a high-density, multi-array layout which can easily fit for high-speed recording as well as color recording. In addition, the apparatus employed in this method is simpler in construction than conventional apparatuses. Hence, a recording head can be reduced in size as a whole and is suitable for mass-production. This method can also easily provide a wide-rage recording head in which many orifices are arranged by taking advantage of remarkable IC technologies and microscopic processing techniques and of an increase of reliabilities in the semiconductor field. Thus, the method is broad in the scope of applications. As shown in Fig. 1 and disclosed in the EP-A-0 419 193, the ink jet recording head for use in ink jet recording is composed of a first substrate 101 (hereinafter to be referred to as a heater board) equipped with electro-thermal converting elements and a second substrate 102 which has grooves for forming a liquid chamber accommodating the ink and ink passages by joining the first substrate 101 to the second substrate 102. The second substrate 102 integrally has an orifice plate 104 which includes ink ejection outlets 109, that is, orifices, communicating with the ink passages (the second substrate will hereinafter to be referred to as a grooved top plate). The heater board 101 is adhered and fixed to a supporting base plate 103 with the use of an adhesive. The grooved top plate 102 is bonded with the heater board 101 in such a manner that the electro-thermal converting elements disposed on the heater board 101 register with the grooves for ink passages formed in the grooved top plate 102. The orifice plate 104 of the grooved top plate 102 is disposed so as to project forward and downward like an apron from a front end surface of the supporting base plate 103. Grooves 103A are formed in a part of the area of the supporting base plate 103 which is covered by the orifice plate 104, more specifically, in the area that is covered by right and left end portions of the orifice plate 104. The ink is supplied from an ink feed member 105 through an ink feed port 102a provided in an upper portion of the grooved top plate 102. The ink feed member 105 has a projecting bar and is fixed to the supporting base plate 103 by inserting this projecting bar into a through hole provided in the supporting base plate 103 and thermally caulking the through hole. The gaps 110a and 110b, between the ink feed member 105 and the heater board 101, and, between the ink feed member 105 and the grooved top plate 102, as well as a joining area with a tiny gap between the orifice plate 104 and the front end surface of the supporting base plate 103 which is to be sealed with an adhesive, constitute an adhesion space which is filled with a sealing compound from above the ink feed member 105 through the grooves 103A. The ink jet recording head as described above has several problems with production as indicated below. 1) In Fig. 1, the joining area between the orifice plate 104 and the front end surface of the supporting base plate 103 has so small gap that the sealing compound often fails to reach the gap, particularly, its central portion, in a sufficient amount. To avoid this problem, it has been a customary practice to lower the viscosity of the sealing compound. The lowering of its viscosity, however, causes the sealing compound to go out of holes provided in the supporting base plate 103, i.e. a mounting hole for a presser spring to be mounted to provide a close contact between the second substrate 102 with the ink passages and the heater board 101, and a hole for insertion of an ink supply pipe of the ink feed member 105 for suppling the ink from an ink tank, as well as a gap in a posterior portion of the ink feed member 105. As a result, the amount of the sealing compound may be insufficient. Moreover, a protrusion which will serve as a reference object when the ink jet recording head is mounted on the carriage may be coated with the sealing compound, thus deteriorating the accuracy and precision of mounting, thereby, for instance, causing a recorded line to be curved. Furthermore, the sealing compound may invade the orifices, causing the ink not to be ejected. An object of the present invention is to provide a process for producing an ink jet recording head which enables a sealing compound to be filled satisfactorily into a joining area between the respective members. This object is achieved by a process according to claim 1. Further improvements are subject-matter of the appended dependent claims. Fig. 1 is a simplified front view showing an example of a conventional ink jet recording head. Fig. 2 is a simplified sectional view showing an embodiment of the ink jet recording head in accordance with the present invention. Fig. 3 is a simplified front view showing the ink ejection outlet side as shown in Fig. 2. Fig. 4 is a perspective view showing an example of a supporting base plate constituting the ink jet recording head in accordance with the present invention. Figs. 5A to 5D are perspective views showing other examples of a supporting base plate constituting the ink jet recording head in accordance with the present invention. Fig. 6 is an exploded perspective view of the ink jet recording head in accordance with the present invention. Fig. 7 is an exploded perspective view of an example of an ink jet cartridge to which the present invention has been applied. Fig. 8 is a perspective view of an ink jet cartridge to which the present invention has been applied. Fig. 9 is a perspective view of an ink tank of the ink jet cartridge as viewed from the side where the ink jet recording head is mounted. Fig. 10 is a top view showing the manner in which the ink jet cartridge is mounted on the carriage of the recording apparatus body. Fig. 11 is a perspective view showing an ink jet recording apparatus to which the present invention has been applied. Embodiment 1 Fig. 2 is a simplified sectional view showing an embodiment of the ink jet recording head in accordance with the present invention. Fig. 3 is a simplified front view of the orifice side of the ink jet recording head as shown in Fig. 2. Fig. 4 is a simplified perspective view showing an example of the supporting base plate which constitutes the ink jet recording head in accordance with the present invention. With reference to Figs. 2, 3 and 4, the embodiment of the ink jet recording head to which the present invention has been applied will be described. As illustrated in Fig. 2, an ink jet recording head is composed of a heater board 101 equipped with electro-thermal converting elements, and a second substrate 102 which is joined to the heater board 101 to form recesses and projections constituting a liquid chamber 107 accommodating an ink, and ink passages 108. The second substrate 102 integrally has an orifice plate 104 which includes orifices 109 communicating with the ink passages 108 for ejecting the ink (the second substrate will hereinafter be referred to as a grooved top plate). The heater board 101 is fixed to a supporting base plate 103 with the use of an adhesive. The grooved top plate 102 is joined to the heater board 101 in such a manner that the electro-thermal converting elements disposed on the heater board 101 will register with the ink passages 108 of the grooved top plate 102. The orifice plate 104 of the grooved top plate 102 is disposed so as to project forward and downward like an apron from a front end surface of the supporting base plate 103. The ink is supplied from an ink feed member 105 through an ink feed port 102a provided in an upper portion of the grooved top plate 102. The ink feed member 105 has a projecting bar (not shown), and is fixed to the supporting base plate 103 by inserting this projecting bar into a through hole provided in the supporting base plate 103 and thermally caulking the through hole. The gaps 110a and 110b (see Fig. 7) between the ink feed member 105 and the heater board 101 and between the ink feed member 105 and the grooved top plate 102 as well as a joining area with a tiny gap between the orifice plate 104 and the front end surface of the supporting base plate 103 which is to be sealed with an adhesive, are filled with a sealing compound as an adhesion space. A neighborhood of the orifice plate 104 which constitutes the ink jet recording head is about 30-40 µm in thickness, but desirably becomes thicker toward a lower portion of the supporting base plate 103 and has a thickness of 0.2 mm in the present embodiment. In view of the costs and ink resistance of the materials, thermoplastic resins such as polyimide, polyether ether ketone, or polysulfone can be cited as examples of the materials for the grooved top plate 102 having the orifice plate 104. In the present embodiment, polysulfone with a small amount of heat deformation at high temperatures was used. In Fig. 3, the shaded portion represents the area filled with the sealing compound. As illustrated in Fig. 4, the supporting base plate 103 has grooves 103A formed at the right and left end portions of the area hung over by the orifice plate, and also has grooves 103B formed within an area, where the heater board 101 is to be bonded, and extending beyond this area. The groove 103B is 0.5 mm wide, 0.5 mm deep, and 1 mm in the dimension beyond said area. The thickness of the adhesive is 0.04 mm so that the adhesive usable for the heater board 101 is not to fill up the groove 103B. The groove 103B is not restricted to this size, and may be of any size which permits a thoroughly satisfactory sealing with the adhesive. The heater board 101 is fixed onto the supporting base plate 103 with the use of the adhesive, and the grooved top plate 102 is fixed onto the heater board 101 so that the electro-thermal converting elements disposed on the heater board 101 and the ink passages 107 of the grooved top plate 102 can be registered with each other. The grooved top plate 102 has the orifice plate 104, and the orifice plate 104 is disposed like an apron in front of the front end surface of the supporting base plate 103. The ink feed member 105 is fixed to the supporting base plate 103 by inserting a projecting bar (not shown) provided in the ink feed member 105 into a through hole provided in the supporting base plate 103, and thermally caulking the through hole. In this case, uniform gaps 110a and 110b are formed between the orifice plate 104 and the ink feed member 105. In this embodiment, the gaps 110a and 110b are within the range form 0.1 to 0.2 mm. The sealing compound is poured through a pour port (not shown) in an upper portion of the ink feed member 105, thereby sealing a wire bonding for transmitting electrical signals, and simultaneously sealing the gaps 110a and 110b between the orifice plate 104 and the ink feed member 105. Then, the sealing compound passes through the grooves 103A and 103B provided in the supporting base plate 103, and completely seals the gapped area between the orifice plate 104 and the front end surface of the supporting base plate 103. That is, the shaded portion as shown in Fig. 3 is filled with the sealing compound. The sealing compound in the present embodiment is a two-part setting polyurethane adhesive which permits the admission of little air into the liquid chamber 107 and which is suitable for the sealing of the wire bonding as mentioned above. Its available viscosity is within the range form 3,000 to 7,000 cps and making the viscosity, making a higher value than that of the prior art. The groove 103B formed in the upper surface of the supporting base plate 103 can be press-molded in the case of mass production. A plurality of the grooves 103B may be formed, and in this case, these grooves may be arranged in a parallel or in a radial form. The shape of this groove may be square or semicircular in cross section. Figs. 5A to 5D show examples of its shape. Irrespective of the number and shape of the grooves 103B, it is necessary to determine the method of applying the adhesive for the heater board 101, the thickness of the adhesive, etc. so that the adhesive may not fill up these grooves. As described above, the supply of the sealing compound into those gaps can be facilitated by the grooves provided in the supporting base plate 103 below the heater board 101 with regard to the sealing of the gaps between the front end surface of the supporting base plate and the orifice plate region. Hence, the use of a high-viscosity sealing compound can be achieved in the present invention. Embodiment 2 Fig. 6 is an exploded perspective view of the ink jet recording head in accordance with the present invention. In Fig. 6, the reference numerals 1105a, 1105b and 1105c denote electro-thermal converting elements provided at predetermined positions of a heater board 1102. The heater board 1102 is provided on a support member 1101. A top plate member 1103 is constituted of an integral combination of an orifice plate 1103A where orifices 1106a, 1106b and 1106c are open, and a top plate 1103B where the grooves for the ink passages and a common liquid chamber are provided. An ink jet recording head is constituted by joining the top plate member 1103 with the heater board 1102 together by use of adhesives 1104a and 1104b. The joining of the top plate member 1103 and the heater board 1102 requires the registration of these members. Figs. 7 to 11 are explanatory views for illustrating an ink jet unit (IJU), an ink jet head (IJH), an ink tank (IT), an ink jet cartridge (IJC), an ink jet recording apparatus body (IJRA), and a carriage (HC) which are preferred for the application of the present invention, and the relationships among these constituent members. Each component structure will be described with reference to these drawings. The ink jet cartridge (IJC) in the present embodiment, as seen from the perspective view of Fig. 8, has a large capacity for accommodating the ink, and has such a shape that a front end portion of the ink jet unit IJU projects slightly from the front face of the ink tank IT. This ink jet cartridge IJC is fixed and supported by a positioning means and an electric contact (to be described later) of the carriage HC (Fig. 10) which is laid on the ink jet recording apparatus body IJRA. The ink jet cartridge IJC is also of a disposable type detachable from the carriage HC. Figs. 7 to 11 show constructions to which a number of novel techniques achieved during the establishment of the present invention have been applied. The whole constitution of the present invention will be described along with a brief explanation for these constructions. (i) Construction of the ink jet unit IJU The ink jet unit IJU is a unit of an ink jet apparatus in which an electro-thermal converting element generates thermal energy to produce film boiling in the ink for performing recording in response to an input electric signal. In Fig. 7, the reference numeral 1150 denotes a heater board composed of electro-thermal converting elements arranged in an array geometry on a silicon substrate and an electric wiring made of aluminum which supplies an electric power to the electro-thermal converting elements, the constituent elements being formed by a film forming technology. Reference numeral 1250 denotes a wiring substrate connected to the heater board 1150 formed a wiring corresponding to the wiring of the heater board 1150 (these wirings are connected together, for example, by wire bonding), and pads 1201 located at an end portion of the wiring for receiving electric signals from the apparatus body. Reference numeral 1300 denotes a grooved top plate provided with partitions for defining individual an ink passage and a common liquid chamber for accommodating the ink to feed the ink to each ink passage and so forth. The grooved top plate 1300 is a one-piece molded product consisting of the ink receptacle port 1500 for receiving the ink supplied from the ink tank IT and introducing the ink into the common liquid chamber, and an orifice plate 400 having a plurality of ink ejection outlets corresponding to the respective ink passages. Although the preferred material for the one-piece molded product is polysulfone, another kind of molding resin may be acceptable. Reference numeral 350 denotes a support member made of, that is, a metal which supports the reverse side of the wiring substrate 1250 by a flat surface thereof, and which defines a bottom of the ink jet unit. Reference numeral 500 denotes a presser spring shaped like a letter M. The presser spring 500 slightly presses the common liquid chamber with the center of the presser spring in a shape of the letter M, and at the same time, its apron portion 1501 presses a portion of the ink passage, preferably, a region in the neighborhood of the ejection outlet, with a linear pressure generated when a force is concentrated at the apron portion 1501. Legs of the presser spring 500 penetrate through holes 3121 of the support member 350 and are fixed in the reverse side of the support member 350 so that the heater board 1150 and the top plate 1300 are held between the presser spring 500 and the support member 350. That is, the heater board 1150 and the top plate 1300 can be fixed and contacted to each other by a rebound force generated with the presser spring 1510 and its apron portion 1501. The support member 350 has locating holes 1312, 1900 and 2000 into which the locating protrusion 1012 and protrusions 1800, 1801 for locating and supporting by heat fusion are inserted respectively. These protrusions 1012, 1800 and 1801 are provided on the ink tank IT. The support member 350 has protrusions 2500 and 2600 for locating the carriage HC of the apparatus body IJRA in its rear side. In addition, the support member 350 has a hole 1320 through which an ink supply pipe 2200 (to be disclosed later) of capable of supplying ink from the ink tank IT is inserted. The mounting of the wiring substrate 1250 on the support member 350 is performed by bonding with an adhesive or the like. Concave portions 2400a and 2400b of the support member 350 are provided in the neighborhood of the locating protrusions 2500 and 2600, respectively. In the assembled ink jet cartridge IJC (see Fig. 8), the concave portions 2400a and 2400b are located on the extension line from the apex portion of the recording head unit IJU, three sides of which are defined by a portion having a plurality of parallel grooves 3000 and 3001. Therefore, the concave portion 2400 makes it possible to keep an unfavorable dust and ink sludge away from the protrusions 2500 and 2600. As will be seen from Fig. 10, a cover member 800 on which the parallel grooves 3000 are formed constitutes an outer wall of the ink jet cartridge IJC and defines a space for accommodation of the ink jet unit IJU together with the ink tank. An ink supply member 600 having another parallel grooves 3001 includes an ink conduit 1600 which is arranged as a cantilever with its fixed end on the side of the ink supply pipe 2200 and is connected to the ink supply pipe 2200. A sealing pin 602 is inserted into the ink conduit 1600 for securing a capillary action between the fixed end of the ink conduit 1600 and the ink supply pipe 2200. In addition, reference numeral 601 denotes a packing for sealing a joint portion between the ink tank IT and the ink supply pipe 2200. In addition, reference numeral 700 denotes a filter placed at the end portion of the ink supply pipe 2200 on the side of the ink tank IT. Since the ink supply member 600 is molded, it is attained at a low cost and is finished with positional accuracy, thus increasing in the accuracy and precision of production of the ink supply member 600. Furthermore, it is possible to keep a stable state pressure welding the ink conduit 1600 onto the ink receptacle port 1500 in mass production in the ink supply member 600 of the ink supply member 600 owing to the cantilever structure of the ink conduit 1600. In this embodiment, it is possible to secure a perfect ink flow path without leakage only by pouring a sealing adhesive from the ink supply member side under the conditions of pressure welding. The fixing of the ink supply member 600 to the support member 350 is performed easily by putting pins (not shown) at the rear side of the ink supply member 600 into holes 1901, 1902 of the support member 350, and bonding the protruding portions of the pins with the rear face of the support member 350 by heat fusion method. These heat-bonded slight projections of the pins are held in a relevant concave portion (not shown) on the side surface of the ink tank IT where the ink jet unit IJU is mounted. Thus, the positioning side of the ink jet unit IJU is fixed correctly with the ink tank IT. (ii) Structure of the ink tank IT The ink tank IT is composed of a cartridge body 1000, an ink absorber 900, and a cover plate 1100. The cover plate 1100 is used to seal the ink absorber 900 after inserting the ink absorber 900 into the cartridge body 1000 from the opposite side of the cartridge body 1000 to its surface where the ink jet unit IJU is mounted. The ink absorber 900 is used to be impregnated with ink and placed in the cartridge body 1000. Reference numeral 1200 denotes an ink supply port for supplying ink to the ink jet unit IJU comprising of the above-mentioned components 100 through the ink supply member 600. In addition, the port 1200 is used as an inlet for pouring ink into the absorber 900 and impregnating with ink prior to disposing the ink jet unit IJU at a portion 1010 of the cartridge body 1000. In this embodiment, the ink can be supplied into the ink tank IT through a port communicating to an atmospheric air 1401 or said ink supply port 1200. However, it is important to pour ink through the ink supply port 1200 for the purpose of pouring ink into the absorber 900 relatively efficiently and uniformly. This is because the empty space filled with air in the ink tank IT, which is composed of ribs 2300 in the cartridge body 1000 and partial ribs 2400 and 2500 of the cover plate 1100 in order to supply ink efficiently from the absorber 900, occupies a corner space communicating with the port 1401 and being the most distant from the ink supply port 1200. This manner of ink supply is very effective for practical use. The cartridge body 1000 has four ribs parallel to the moving direction of the carriage. These four ribs are arranged on the rear surface of the cartridge body 1000 so as to prevent the absorber 900 from contacting the rear surface of the cartridge body 1000 of the ink tank. The partial ribs 2400 and 2500 are also placed on the inner surface of the cover member 1100 positioned on the extension line from the ribs 2300. In contrast with the rib 2300, the partial ribs 2400 and 2500 are composed of many small pieces so that their volume of empty space filled with air becomes larger than that for the ribs 2300. The partial ribs 2500 and 2400 are distributed over a half or less of the whole area of the cover member 1100. With these ribs, the flow of ink from the corner region of the ink tank IT most distant from the ink supply port 1200 is stabilized, so that the ink can be introduced securely from every region of the absorber 900 into the ink supply port 1200 by capillary action. The port communicating to an atmospheric air 1401 is an open hole provided in the cover member 1100 for communicating the inside of the cartridge with the atmosphere. Reference numeral 1400 denotes a water repellent disposed inwardly of the port communicating to an atmospheric air 1401 for preventing ink leakage from this port 1401. That space of the ink tank IT where ink is accommodated is a rectangular parallelepiped whose longer side corresponds to the side of the ink tank IT. Hence, the layout of the ribs as described above is effective particularly in this case. If the ink tank IT has its longer side in the direction of the movement of the carriage or has a cubic space for ink accommodation, the supply of ink from the ink absorber 900 can be stabilized by providing the ribs on the whole area of the cover member 1100. A rectangular parallelepiped shape is suitable for accommodating as much ink as possible in a limited space. It is important to provide ribs 2300, 2400 and 2500. This can achieve the above effect at two side areas in the neighborhood of corners of the ink tank IT to use the accommodated ink without waste for recording. In addition, the inside ribs of the ink tank IT are almost uniformly distributed in the thickness direction of the ink absorber 900 in a rectangular parallelepiped shape. This arrangement is important for enabling an atmospheric pressure to be applied uniformly on the ink retained in the ink absorber 900 so that the ink in the ink absorber 900 can be used up leaving the least amount of waste ink. Furthermore, the technological concept of positioning of the ribs will be described in detail below. Let it be assumed that the ink supply port 1200 of the ink tank is projected onto the top quadrilateral side of the rectangular parallelepiped. When a circular arc is drawn with the length of the longer side of the ink tank IT as its radius as the center of the position of the projection. Here, it is important that the ribs be disposed on a plane outward of the circular arc so that an atmospheric pressure rapidly applies to the ink absorber 900 positioned outwardly of the circular arc. The port communicating to an atmospheric air 1401 is not restricted to the position of the embodiment as long as it can introduce an atmospheric air into the area where the ribs are disposed. In addition, in this embodiment, the rear surface of the ink jet cartridge IJC is made plane so that the space required to incorporate the cartridge IJC of the apparatus is minimized, and the amount of ink accommodated is maximized. As a result, the size of the apparatus is made smaller, and the replacement frequency of the ink jet cartridge can be reduced. Furthermore, a projected portion for providing the port communicating to an atmospheric air 1401 is formed by utilizing the rear portion of the space for integrating the ink jet unit IJU to the ink tank IT. Inside the projected portion, a hollow is formed in which a space 1402 for applying an atmospheric pressure to the entire thickness of the ink absorber 900 is provided. An unprecedentedly excellent ink cartridge can be provided by constructing as mentioned above. The space 1402 for applying an atmospheric pressure is much larger a space than that of a conventional apparatus. Since the port communicating to an atmospheric air 1401 is located in its upper side, the space 1402 can temporarily hold the ink even if the ink leaks accidentally from the ink absorber 900. The space 1402 can retrieve the ink into the absorber 900 reliably. A structure of the mounting face of the ink tank IT to which the unit IJU is mounted is shown in Fig. 9. When a line L 1 is taken to be a straight line passing through the center of the ink ejection outlet of the orifice plate 400 and parallel to the bottom face of the ink tank IT or to the reference plane on the surface of the carriage, the protrusion 1012, for registration to be engaged with the hole 1312 of the support member 350 are on the line L 1 . The height of the protrusion 1012 is a little less than the thickness of the support member 350, and the support member 350 is positioned with respect to the protrusion 1012. On the extension line L 1 , as shown in Fig. 9, a click 2300 is disposed for engaging with a right angular hook surface 4002 of a locating hook 4001 which is provided on the carriage. Hence, an action force for positioning the cartridge is applied to a surface region including the line L 1 and parallel to the reference face as mentioned above. As will be explained with reference to Fig. 11, this layout relationship forms an effective structure to make the accuracy of positioning only the ink tank equivalent to that of positioning the ink ejection outlet of the ink jet recording head. In addition, the length of the protrusions 1800, 1801 to be inserted in the holes 1900, 2000 for fixing the support member 350 to the side surface of the ink tank IT is greater than that of the protrusion 1012 as mentioned above. The projections 1800, 1801 are used for fixing the support member 350 on the side surface of the ink tank IT by penetrating through the holes 1900, 2000 of the support member 350 and by bonding an end portion of the protrusions 1800, 1801 with the support member 350 by a heat fusion method. Let L 3 be a straight line intersecting perpendicularly with the straight line L 1 and passing the protrusion 1800, and let L 2 be a straight line intersecting perpendicularly with the straight line L 1 and passing the protrusion 1801. Nearly the center of the ink supply port 1200 as mentioned above is positioning on the straight line L 3, so that, the protrusion 1800 acts for stabilizing the state of connection situation between the ink supply port 1200 and the ink supply pipe 2200 so as to make it possible to reduce an overload on this connection situation in the case of their dropping and/or shock to them. Since the straight lines L 2 and L 3 do not intersect at any point, and there are protrusions 1800, 1801 in the neighborhood of the protrusion 1012 at the side of the ink ejection outlet of the head IJH, a reinforcement effect acts for positioning the head IJH on the ink tank IT. A curve L 4 shows a position of an outside wall of the ink supply member 600 when the member 600 is mounted. Since the protrusions 1800, 1801 are disposed along the curve L 4 , they provide enough high strength and dimensional accuracy by applying the weight load of the structure at the front end side of the head IJH. Reference numeral 2700 denotes a nose flange of the ink tank IT which is inserted into a hole in a front plate 4000 of the carriage so as to prevent an abnormal situation in which the displacement of the ink tank becomes extremely large. Reference numeral 2101 designates a stop for preventing the cartridge IJC from slipping off the carriage HC, and is placed in correspondence to a bar (not shown) of the carriage HC. With this arrangement, when the cartridge IJC is mounted by being turned on the carriage as will be described later, the stop 2101 enters into a lower side of the bar, so that, the cartridge IJC maintains its position even if such an accidental upward force as separating the cartridge IJC from its normal mounting position acts on the cartridge IJC. The unit IJU is mounted inside of the cartridge IJC, and then is closed with the cover 800 so that the unit IJU is surrounded by the cartridge IJC except an under side of the cartridge IJC. However, this under side opening is close to the carriage HC when the cartridge is mounted on the carriage HC, thereby establishing a substantially perfectly closed space around the unit IJU. Accordingly, although heat generated from the head IJH within this closed space is effective as a heat jacket, the temperature of the closed space increases slightly during long-term continuous use of the head IJH. In this embodiment, therefore, a slit 1700 with a smaller width than that of the closed space is formed in the upper deck of the cartridge IJC for promoting a natural heat dissipation from the support member 300. Besides, the slit 1700 can establish an uniform temperature distribution in the whole unit IJU irrespective of the environment for preventing an increase of temperature within the closed space. By assembling the cartridge IJC from the ink tank IT and the unit IJU, the ink can be fed from the ink tank IT into the ink supply tank 600 through the ink supply port 1200, the hole 1320 of the support member 350, and an inlet provided on a rear surface of the supply tank 600. After the ink passes through the inside of the supply tank 600, the ink flows into the common liquid chamber through a suitable supply tube and the ink inlet 1500 of the top plate 1300 from the ink outlet of the supply tank 600. The gaps formed at connecting portions of these components for supplying ink are filled with a packing such as a silicone rubber or butyl rubber for sealing the gaps, and an ink feed route is thus secured. As described above, the ink supply member 600, the single module of the top plate with the orifice plate and the ink tank body 1000 constitute a one-piece molded product. Therefore, a high accuracy of assemblage is attained, and the grade of the mass-production is increased remarkably. In addition, the number of parts may be reduced in comparison with a conventional assemblage by assembling the parts into a single molded component, thus attaining the excellent desired characteristics securely. In this embodiment, as shown in Figs. 7. to 11, the ink supply member 600 has an upper surface portion 603 which forms a slit S (see Fig. 8) with respect to an end portion 4008 of the roof portion of the ink tank IT which is provided with a slit 1700 after assembly in the above manner. Another slit (not shown) similar to the slit S is formed between a lower surface portion 604 of the ink supply member 600 and a head side end portion 4011 of a thin plate member to which a lower cover 800 of the ink tank IT is joined by bonding. These slits between the ink tank IT and the ink supply member 600 not only serve to enhance the heat dissipation from the slit 1700, but also prevent undue forces applied to the ink tank IT from directly exerting on the supply member 600 or the ink jet unit IJT. Anyway, the constructions in this embodiment as mentioned above are unprecedented, and each of them produces marked effects independently, and when combined with one another, brings about organized effects because of its constituent elements (iii) Mounting of the ink jet cartridge IJC to the carriage HC In Fig 10, reference numeral 5000 denotes a platen roller for guiding a recording medium P from a lower side of the drawing to its upper side. The carriage HC moves along the platen roller 5000. Therefore, the carriage HC has a front plate 4000 (with a thickness of 2 mm) in front of the ink jet cartridge IJC on the forward side facing the platen roller 5000. The carriage HC also has a flexible sheet 4005 provided with pads 2011 corresponding to pads 1201 on the wiring substrate 1250 of the cartridge IJC; a support board 4003 for electrical connection which supports a rubber pad sheet 4007 for generating an elastic force for pressing the reverse side of the flexible sheet 4005 onto the pads 2011; and a positioning hook 4001 for holding the IJC at the recording position. The front plate 4000 has two locating protruding surface 4010 corresponding to the aforementioned locating protrusions 2500 and 2600 of the support member 350. The locating protruding surface 4010 receives a vertical pressure heading for the surface 4010 after the cartridge IJC is mounted in the carriage HC. Hence, the front plate 4000 has a plurality of reinforcing ribs (not shown) elongating in the direction of opposing the vertical pressure on the side of the platen roller 5000. The ribs also form a head for protecting protrusion which is slightly closer by about 0.1 mm to the platen roller 5000 than the position of the front surface, L 5 , of the cartridge IJC when mounted. The support plate 4003 for electrical connection has a plurality of reinforcing ribs 4004 elongating in the vertical direction to the elongating direction of the above-mentioned reinforcing ribs of the front plate 4000. The amount of the protrusion of the ribs 4004 is gradually decreased along the direction from the platen roller 5000 side to the hook 4001 side. This configuration of the ribs 4004 also enables the cartridge IJC to be positioned inclinatorily when mounted, as shown in Figs. 10. The support plate 4003 has the locating surface 4006 on the hook side in order to stabilize electrical connection. The locating surface 4006 correspond to the above-mentioned protruding surface 4010 and exert a force on the cartridge in a direction opposite to the direction in which the locating protruding surface 4010 exert on the cartridge. The locating surface also has a pad contact region defined therebetween, and prescribe the amount of deformation of the pads of the padded rubber sheet 4007 corresponding to the pad 2011. Once the cartridge IJC is fixed in the recording position, the locating surface 4006 contacts with the surface of the wiring substrate 350. Moreover, in this embodiment, the pads 201 of the wiring substrate 350 are arranged symmetrically with respect to the line L 1 . Therefore, the amount of deformation of the pads on the rubber sheet 4007 is made uniform, and a contact pressure between the pads 2011 and 201 is more stabilized. In this embodiment, the pads 201 are arranged in an array with 2 center rows, with 2 upper columns and with 2 lower columns. The hook 4001 has a slot engaging with an fixing shaft 4009. The hook 4001 is rotated counterclockwise from the position shown in the drawing by use of a movable space defined by the slot, and then moved leftward in parallel to the platen roller 5000, thereby locating the ink jet cartridge IJC on the carriage HC. Although any means may be used to move the hook 4001 in the above manner, a movement mechanism with a lever or the like is preferable. Anyway, the cartridge IJC moves to the platen roller side in response to the rotating movement of the hook 4001, and at the same time, the locating protrusions 2500 and 2600 move to the position where they can come into contact with the locating surface 4010 of the front plate. Upon the leftward movement of the hook 4001, the hook surface 4002 with an angle of 90° to the' hook 4001 closely contacts with the surface with an angle of 90° to the click 2100 of the cartridge IJC. At the same time, the cartridge IJC is rotated on a horizontal plane about the region of contacting the locating surfaces 2500 and 4010. As a result, the pads 201 and 2011 begin to contact each other. When the hook 4001 is held in a predetermined position or a fixed position, a perfect contact between the pads 201 and 2011, a perfect facial contact between the positioning surfaces 2500 and 4010, a two-surface contact between the surface 4002 with an angle of 90° to the hook and the surface with an angle of 90° to the click 2100, and a facial contact between the wiring substrate 350 and the positioning surface 4006 are formed. Thus, the mounting of the cartridge IJC on the carriage HC is completed. (iv) Outline of the apparatus body Fig. 11 illustrates the outline of an ink jet recording apparatus IJRA to which the present invention is applied. A lead screw 5005 is rotated reversibly via gears for transmitting driving force 5011, 5009 in association with the reversible rotation of a driving motor 5013. The carriage HC meshing with a spiral groove 5004 of the lead screw 5005 has a pin (not shown) and is moved in either direction of arrow a or b. Reference numeral 5002 denotes a paper pressure plate, which presses a paper against the platen roller 5000 over a range along the moving direction of the carriage HC. Reference numerals 5007, 5008 denote photocouplers, which detects the presence of a lever 5006 of the carriage in the region where the photocouplers are disposed. The photocouplers serve as a means for sensing home position for switching the direction of rotation of the motor 5013 upon sensing of such presence. Reference numeral 5016 denotes a support member for supporting a cap member 5022 which caps the front side of the recording head. Reference numeral 5015 denotes a sucking means for making the inside of the cap member 5022 at negative pressures so that the ink of the recording head is absorbed through an opening 5023 within the cap member. Reference numeral 5017 denotes a cleaning blade. Reference numeral 5019 denotes a member for enabling the cleaning blade 5017 to move forward or backward. The cleaning blade 5017 and the member 5019 are supported by a plate for supporting body 5018. As for the cleaning blade 5017, it goes without saying that a well-known cleaning blade is applicable to the present invention. Reference numeral 5012 denotes a lever for starting an absorbing procedure by the sucking member 5015. The lever 5012 moves in correspondence to the movement of a cam 5020 which engages with the carriage HC so that a driving force from the driving motor 5013 is transmitted to the sucking member 5015 by a known transmission mechanism such as switching of a clutch. These capping, cleaning and absorbing operations are so contrived that the desired operation can be performed at their corresponding positions by the action of the lead screw 5005 when the carriage has come to the region of the home position side. However, any arrangement in which the desired operation can be performed at an appropriate time is applicable to the present embodiment. The present invention achieves distinct effect when applied to a recording head or a recording apparatus which has means for generating thermal energy such as electrothermal transducers or laser light, and which causes changes in ink by the thermal energy so as to eject ink. This is because such a system can achieve a high density and high resolution recording. A typical structure and operational principle thereof is disclosed in U.S. patent Nos. 4,723,129 and 4,740,796, and it is preferable to use this basic principle to implement such a system. Although this system can be applied either to on-demand type or continuous type ink jet recording systems, it is particularly suitable for the on-demand type apparatus. This is because the on-demand type apparatus has electrothermal transducers, each disposed on a sheet or liquid passage that retains liquid (ink), and operates as follows: first, one or more drive signals are applied to the electrothermal transducers to cause thermal energy corresponding to recording information; second, the thermal energy induces sudden temperature rise that exceeds the nucleate boiling so as to cause the film boiling on heating portions of the recording head; and third, bubbles are grown in the liquid (ink) corresponding to the drive signals. By using the growth and collapse of the bubbles, the ink is expelled from at least one of the ink ejection orifices of the head to form one or more ink drops. The drive signal in the form of a pulse is preferable because the growth and collapse of the bubbles can be achieved instantaneously and suitably by this form of drive signal. As a drive signal in the form of a pulse, those described in U.S. patent Nos. 4,463,359 and 4,345,262 are preferable. In addition, it is preferable that the rate of temperature rise of the heating portions described in U.S. patent No. 4,313,124 be adopted to achieve better recording. U.S. patent Nos. 4,558,333 and 4,459,600 disclose the following structure of a recording head, which is incorporated to the present invention: this structure includes heating portions disposed on bent portions in addition to a combination of the ejection orifices, liquid passages and the electrothermal transducers disclosed in the above patents. Moreover, the present invention can be applied to structures disclosed in Japanese Patent Application Laying-open Nos. 123670/1984 and 138461/1984 in order to achieve similar effects. The former discloses a structure in which a slit common to all the electrothermal transducers is used as ejection orifices of the electrothermal transducers, and the latter discloses a structure in which openings for absorbing pressure waves caused by thermal energy are formed corresponding to the ejection orifices. Thus, irrespective of the type of the recording head, the present invention can achieve recording positively and effectively. The present invention can be also applied to a so-called full-line type recording head whose length equals the maximum length across a recording medium. Such a recording head may consists of a plurality of recording heads combined together, or one integrally arranged recording head. In addition, the present invention can be applied to various serial type recording heads: a recording head fixed to the main assembly of a recording apparatus; a conveniently replaceable chip type recording head which, when loaded on the main assembly of a recording apparatus, is electrically connected to the main assembly, and is supplied with ink therefrom; and a cartridge type recording head integrally including an ink reservoir. It is further preferable to add a recovery system, or a preliminary auxiliary system for a recording head as a constituent of the recording apparatus because they serve to make the effect of the present invention more reliable. As examples of the recovery system, are a capping means and a cleaning means for the recording head, and a pressure or suction means for the recording head. As examples of the preliminary auxiliary system, are a preliminary heating means utilizing electrothermal transducers or a combination of other heater elements and the electrothermal transducers, and a means for carrying out preliminary ejection of ink independently of the ejection for recording. These systems are effective for reliable recording. The number and type of recording heads to be mounted on a recording apparatus can be also changed. For example, only one recording head corresponding to a single color ink, or a plurality of recording heads corresponding to a plurality of inks different in color or concentration can be used. In other words, the present invention can be effectively applied to an apparatus having at least one of the monochromatic, multi-color and full-color modes. Here, the monochromatic mode performs recording by using only one major color such as black. The multi-color mode carries out recording by using different color inks, and the full-color mode performs recording by color mixing. Furthermore, although the above-described embodiments use liquid ink, inks that are liquid when the recording signal is applied can be used: for example, inks can be employed that solidify at a temperature lower than the room temperature and are softened or liquefied in the room temperature. This is because in the ink jet system, the ink is generally temperature adjusted in a range of 30°C - 70°C so that the viscosity of the ink is maintained at such a value that the ink can be ejected reliably. In addition, the present invention can be applied to such apparatus where the ink is liquefied just before the ejection by the thermal energy as follows so that the ink is expelled from the orifices in the liquid state, and then begins to solidify on hitting the recording medium, thereby preventing the ink evaporation: the ink is transformed from solid to liquid state by positively utilizing the thermal energy which would otherwise cause the temperature rise; or the ink, which is dry when left in air, is liquefied in response to the thermal energy of the recording signal. In such cases, the ink may be retained in recesses or through holes formed in a porous sheet as liquid or solid substances so that the ink faces the electrothermal transducers as described in Japanese Patent Application Laying-open Nos. 56847/1979 or 71260/1985. The present invention is most effective when it uses the film boiling phenomenon to expel the ink. Furthermore, the ink jet recording apparatus of the present invention can be employed not only as an image output terminal of an information processing device such as a computer, but also as an output device of a copying machine including a reader, and as an output device of a facsimile apparatus having a transmission and receiving function.

Claims: A process for producing an ink jet recording head for ejecting ink, said process comprising the following steps: a) joining together a first substrate (101) and a second substrate (102), said first substrate having ejection energy generating elements for supplying energy for ejecting ink, said second substrate (102) integrally having an orifice plate (104) with orifices (109) formed therein for ejecting ink and a front plate portion provided integrally with said orifice plate (104), and grooves and projections for constituting ink passages (108) communicating with said orifices (109) by being joined to said first substrate (101); b) joining a part of a joining member composed of said first substrate (101) and said second substrate (102) to a supporting base plate (103), thereby covering a front surface of said supporting base plate (103) by a part of said front plate portion of said second substrate (102), said joining is performed by using a sealing compound, c) filling said sealing compound into gaps between said front plate portion of said orifice plate (104) and said front surface of said supporting base plate (103), characterized in that said sealing compound is filled through a groove (103B) formed in a part of a top surface of said supporting base plate (103) to which said first substrate is joined, said groove (103B) extends beyond said part of said top surface to be joined. A process as claimed in claim 1, characterized in that a plurality of said grooves (103B) extend radially from the neighbourhood of the center of said orifice plate (104). A process as claimed in claim 1, characterized in that said ejection energy generating elements generate thermal energy to generate a bubble and the ink is ejected accompanied by generating said bubble. A process as claimed in claim 1, characterized in that said ink jet recording head accomodates ink to be ejected from said orifices (109).

Inventors: GOTO AKIRA, ICHIKAWA FUMIO, MAEOKA KUNIHIKO, MASUDA KAZUAKI, ORIKASA TSUYOSHI, SATO OSAMU, WATANABE TAKASHI, GOTO, AKIRA, ICHIKAWA, FUMIO, MAEOKA, KUNIHIKO, MASUDA, KAZUAKI, ORIKASA, TSUYOSHI, SATO, OSAMU, WATANABE, TAKASHI, GOTO, AKIRA, C/O CANON KABUSHIKI KAISHA, Ichikawa, Fumio, c/o Canon Kabushiki Kaisha, MAEOKA, KUNIHIKO, C/O CANON KABUSHIKI KAISHA, MASUDA, KAZUAKI, C/O CANON KABUSHIKI KAISHA, ORIKASA, TSUYOSHI, C/O CANON KABUSHIKI KAISHA, SATO, OSAMU, C/O CANON KABUSHIKI KAISHA, WATANABE, TAKASHI, C/O CANON KABUSHIKI KAISHA
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1992
Main classification: B41J2
IPC codes: B41J2