Cap for an ink jet recording head

Abstract: A cap (2) installed in an ink jet recording head (IJU) for sealing an ink ejection orifice (113i) of the ink jet recording head (IJU) comprises a contacting member (20) and a pressing structure (2, 21B, 21F, 16a, 16b). The contacting member (20) is a member having an elastically deformable convex part (20A) which contacts a face (113e) on which the orifice (113i) is disposed and seals the orifice (113i). The pressing structure (2, 21B, 21F, 16a, 16b) presses the convex part (20A) of the contacting member (20) toward the face (113e) in responsive to installing the cap (2).

Description: The present invention relates to a cap for a recording head used for sealing tightly an ink ejection orifice of an ink jet recording head so as to protect the orifice, and an ink jet recording head in which the cap for a recording head can be mounted. One of the most important factors which determine the reliability in recording information by ink jet recording heads is a physical condition around the ink ejection orifice (hereinafter referred to as "orifice" simply) and a physical condition of ink fluid to be ejected outside the orifice. More specifically, extraneous substances such as dust and liquid drops on and around the orifice may deflect an ink drop let being ejected, and an increase in viscosity of ink in a liquid path near the orifice may lead an ink ejection to be faulty condition such as non-ejection. An attachment of such unfavorable extraneous substances and such increase in viscosity of ink fluid occur when the orifice of the recording head is exposed to the atmospheric air, for example, during ejecting ink for recording information or waiting for recording operation. It is known that, in order to prevent the attachment of such unfavorable extraneous substances and such increase in viscosity of ink, the orifice is capped with an adequate device except when the orifice is used for recording operation or the like, or the surface on which the orifice is disposed is wiped with a blade and so on according to demand. It is easier to remove unfavorable extraneous substances by way of the above mentioned devices in case that the recording head is installed in the recording apparatus. However, in case that the recording head is shipped and transported from the factory to users through temporary storages, it may be required that some preventive method for removing unfavorable extraneous substances on the recording head and for reducing an increase of the viscosity of ink fluid should be employed. Especially in case of exchangeable recording heads which can be installed in and removed from the apparatus body freely, as storage and transportation of such exchangeable recording heads are directed to an individual recording head separated from the recording apparatus, the above mentioned device for capping the recording head installed in the recording head cannot be directly applicable. In addition to the above mentioned problems in removing unfavorable extraneous substances and preventing an increase in the viscosity of ink fluid, it is required to prevent ink fluid leakage due to external force and shock while transporting the recording head and due to a temperature change outside the recording head. In order to solve these problems, in some prior art apparatus, employed is a cap the structure of which is different from that used in the apparatus when installed. An example of such a cap is shown below. As shown in Fig. 1, in Japanese Patent Application Laying-open No. 37436/1986, disclosed is a structure where a cap 70 covers the whole surface on which orifices 71a of the recording head 71 are arranged so that a swelling material inside the cap 70 absorbs ink fluid from the orifices 71a and swells so as to seal the orifices 71a. Alternatively, Figs 2A, 2B and 2C also show a structure where a seal 80 is bonded on the surface on which orifices 81a of the recording head 81 are arranged so that the orifices 81a are sealed. The JP-A-62-019 460 discloses a container for storing an ink jet recording head comprising a contacting member having an elastically deformable convex part. This convex part has the form of a projection which is plugged in a lower hole of the ink jet recording head. The nozzle surface is pressed against a cushion rubber in order to prevent from dripping. And furthermore, with a combination of a seal 90c and a pressing member 90b as shown in Figs. 3A and 3B, by the assignee, proposed is a structure where the seal 90c is pressed against the face 91a on which an orifice 91e of the recording head 91 is disposed. The structure is disclosed in PCT/JP90/01588 not published yet. In this structure, the seal 90c which is larger than the orifice disposed face 91a is bonded onto the orifice disposed face 91a by using bonding materials with relatively weaker adhesive property. The bonded seal 90c is pressed by the pressing member 90b with a designated amount of force developed on the face around the orifices 91e on the orifice disposed face 91a. As a result, the orifices 91e are shielded completely against the atmospheric air and evaporation of ink fluid from the orifices 91e is prevented. A pressing force developed by the pressing member 90b is applied by means that a couple of arms of the cap 90a is caught by a part of the recording head 91 when the cap 90a is installed in the recording head 91. Bonding materials used for contacting the seal 90c and the orifice disposed face 91a have a weak adhesive property as described above. That is, there is no need to guarantee complete sealing of the orifices by bonding the seal 90c itself, and hence, the seal 90c may have an adequate adhesive property so as to establish contacting of the seal 90c on the orifice disposed face. So far, it will be appreciated that the amount of bonding materials can be limited to be small enough to establish contacting of the seal 90c on the orifice disposed face and that unfavorable penetration of excess bonding materials into the orifices can be avoided so that bonding materials may not give unfavorable effect on ink ejection operations. In the above mentioned structures for capping the recording head, the following problems still remain to be unsolved. In the structure using the cap 70 shown in Fig. 1, though ink fluid leakage is prevented even when external force and shock are applied or excess amount of temperature changes occur, there may be a case that leaked ink fluid from the orifices 71a is staying in a space between the swelling material in the space 71b and the cap 70. In this case, for example, when the cap 70 is removed in order to install the recording head in the recording apparatus by the user, ink fluid remained in the space may flow over the cap 70 and may be spattered over hands of the user, and even may lead to electric parts failure due to spilled ink fluid in the recording apparatus. In the structure using the seal 80 as shown in Fig. 2, it may not be easy to install the seal 80 on and around the orifices of the recording head precisely. When removing the seal 80 installed on the orifice disposed face, strong bonding materials used for contacting the seal 80 may be still present on the face near the orifices so that ink fluid ejection failure may be brought. On the other hand, when bonding materials with weak adhesive property is used, the seal of the recording head by the seal 80 is not completely established. And in case that the surface of the orifices is not continuously formed on its neighboring area, the seal 80 cannot seal the surface and its neighboring area completely. Even in the structure as shown in Fig. 3, in case that the surface 91a of the orifices 91 is not continuously formed on its neighboring area and the surface 91a is concave on the neighboring area, it may not be easy to bring the seal 90c into close contact with the orifices 91e by the pressing member 90b. These contact failure leads to incomplete seal to the orifices. For example, in case that the orifice disposed face to be shown in Fig. 8 of the present invention where a cross-sectional shape of the orifice disposed face is a concave (arc) shape and the orifices is not placed in the bottom of the concave shape, the distribution of pressing force developed by the pressing member is not uniform over the concave shape because the shape of the contacting face of the pressing member 90b is a flat plane. That is, there may be a case that pressing member 90b cannot be deformed in responsive to the curved shape of the orifice disposed face and that, as a result, a well-conditioned contact between the seal 90c and the orifices 91e cannot be established. In addition, in the structure shown in Fig. 3, the pressing member 90b is composed of elastic and porous materials such as silicon porous materials and polyurethane porous materials which have a thickness of about three millimeters. In this case, as the pressing member 90b has about 50 cells of air voids per 1 inch, seven to eight orifices may be defined in the corresponding cell. These orifices contacting cells of air voids are not pressed directly by the substantial pressing member 90b through the seal 90c, and these orifices are pressed only by the seal 90c. As a result, which leads to unfavorable phenomena such as an increase in the viscosity of ink fluid absorbed in the pressing member 90b and spilt ink fluid around the orifices. Furthermore, in the above mentioned structure of sealing and capping the recording head, there may be a problem that the number of additive components for sealing and capping the recording head inevitably increases. An object of the present invention is to provide a cap for a recording head which can seal tightly an ink ejection orifice and its neighboring part of the ink jet recording head, and an ink jet recording head which can use the cap. In a first aspect, the object of the present invention, is solved by a cap comprising the features of claim 1. In a second aspect, the object of the present invention, is solved by a container comprising the features according to claim 5. In a third aspect the object of the present invention, is solved by an ink jet recording head comprising the features according to claim 9. The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings. Embodiments of the invention will now be described, by way of example and with reference to the accompanying drawings in which: Fig. 1 is a schematic cross-sectional view of a recording head and a cap sealing the recording head of prior art; Figs. 2A and 2B are perspective views of a recording head and a cap sealing the recording head of related art; Fig. 2C is a side view of the recording head and the cap shown in Figs. 2A and 2B; Figs. 3A and 3B are perspective views of a recording head and a cap sealing the recording head of related art; Fig. 4 is a perspective view of an ink jet recording head which can mount a cap of an embodiment of the present invention; Fig. 5 is an exploded perspective view of the recording head shown in Fig. 4; Fig. 6 is a perspective view showing a recording head shown in Fig. 4 which is capped with a cap of an embodiment of the present invention; Fig. 7 is a perspective view showing a recording head shown in Fig. 4 from which the cap is removed; Fig. 8 is a detailed cross-sectional view of a recording head from which the cap shown in Fig. 4 is removed; Fig. 9 is a detailed cross-sectional view of a recording head capped with the cap shown in Fig. 4; Fig. 10 is a perspective view of an example of a recording head container of the other embodiment of the present invention which is also used as a cap for the recording head; Fig. 11 is a plan view of the recording head container shown in Fig. 10 which contains a recording head; Fig. 12 is a plan view of the other example of a recording head container; Fig. 13 is a perspective view of an example of an ink jet recording apparatus which can record information with the recording head shown in Fig. 4; Fig. 14 is a cross-sectional view of a cap further with a seal in one embodiment of the present invention; Fig. 15 is a cross-sectional view of a recording head with the cap shown in Fig. 14; Fig. 16 is a schematic block diagram showing an example of an apparatus where an ink jet recording apparatus of the present invention is mounted; and Fig. 17 is a schematic block diagram showing a portable printer using an ink jet recording apparatus of the present invention. As will be described, these and other features of the present invention and one embodiment of it are more fully described below in the detailed description and with the accompanying drawings. Fig. 4 shows an example of an ink jet cartridge of one embodiment of the present invention which has a recording head and an ink tank within a single unit. The ink jet cartridge of this embodiment has an ink tank unit IT and a recording head unit IJU in a single body, which can be put on and taken off each other. A connector 102 for receiving signals for driving an ink ejection part 101 of the recording head unit IJU and for transmitting signals for reporting the residual amount of ink fluid to a recording apparatus control part is placed at the side face of the ink jet cartridge. Owing to this structure, it will be appreciated that the height of the ink jet cartridge mounted on a carriage to be described later can be taken to be small enough and the thickness of the ink jet cartridge can be taken to be small enough. So far, as shown in Fig. 13 later, it will be appreciated that in case of arranging a plurality of ink jet cartridges in one dimensional array, the carriage assembly can be taken to be small. In installing the ink jet cartridge in the carriage, the ink jet cartridge can be put on the carriage by carrying the ink jet cartridge with its handle 201 formed at the ink tank unit IT so that the ink ejection part 101 can face downward. The handle 201 is linked to a lever formed at the carriage to be described later which is used when installing the ink jet cartridge into the carriage. When installing the ink jet cartridge into the carriage, the head unit IJU can be positioned by way of a pin formed at the carriage being linked with a pin catcher part 103 formed at the head unit IJU. In the ink jet cartridge of this embodiment, an absorber 104 used for cleaning a member wiping the surface of the ink ejection part 101 is placed beside the ink ejection part 101. In addition, an air duct port 203 used for introducing air as ink fluid consumption proceeds is placed almost at the center of the ink tank unit IT. Fig. 5 is an exploded perspective view of the ink jet cartridge shown in Fig. 4. The ink jet cartridge is composed of the recording head unit IJU and the ink tank unit IT. In the followings, the detailed structure of these units IJU and IT is described. Recording Head Unit IJU: Almost all the component parts of the recording head unit IJU are assembled on a base plate 111 made of Al. On the base plate 111, a substrate 112 on which formed are electronic devices generating thermal energy used for ejecting ink and a print circuit board (PCB) 115 containing electric circuitry for supplying electric power to these devices are mounted, and the substrate 112 and the PCB 115 are connected to each other through wire bonding wirings. On the substrate, installed are electro-thermal conversion elements generating thermal energy used for inducing film boiling in ink fluid in response to electric power supply to the elements. In the following description, the substrate 112 is designated a heater board. The above mentioned connector 102 is a part of PCB 115 through which driving signals from a control circuit not shown in Fig. 5 are received and driving signals are further transmitted to the heater board 112 through PCB 115. In this embodiment, PCB 115 is formed as a two-sides circuit board on which mounted are condenser (not shown) and IC (not shown) made as a ROM device which contains data generic to the recording head such as adequate driving conditions for electro-thermal conversion elements, ID numbers, ink color attributes and supplementary data for driving conditions such as head shading (HS). On the heater board 112, disposed is an upper plate 113 having a concave part forming a common fluid reservoir storing temporarily ink fluid supplied from ink tank unit IT, and a plurality of fluid paths connecting the common fluid reservoir and ink ejection orifices perspectively. In addition, an orifice plate 113A at which orifices are formed is integrally formed with the upper plate 113. A component 114 is a leaf spring for pressing tightly the upper plate 113 against the heater board 112 so that an ink ejection part 101 can be formed. A component 116 is a head unit cover which is formed in a mold containing an ink fluid supply tube part 116A entering into the ink tank unit IT, an ink fluid channel 116B between the ink fluid supply tube part 116A and an ink fluid leading tube part at the upper plate, three pins 116C for fixing the head unit cover on the base plate 111, a pin coupling part 103, a mounting part of an absorber 104 and the lest. As for the ink fluid channel 116B, an ink fluid route cover 117 is placed. A filter 118 for removing small-sized air bubbles and dusts is placed at the top of the ink fluid supply tube part 116A and an O ring is also placed in order to prevent ink fluid leakage from connecting portions of the above mentioned components. In fabricating the above mentioned head unit, a protruding pin 111P formed on the base plate is positioned by being inserted into a penetration hole 115P formed in PCB 115 and both of the protruding pin 111P and the penetration hole 115P are fixed with bonding and so on. In fixing the protruding pin 111P and the penetration hole 115P, precise positioning is not required. This is because fixing of the heater board 112 in response to the base plate 111 which requires high precision can be done independently with respect to PCB 115. Next, the heater board 112 is fixed with higher precision on the base plate 111 and is connected electrically to PCB 115. And the upper plate 113 and the spring 114 are placed with adequate bonding and sealing, and three protruding pins 116C are fixed by being inserted through the hole 111C on the base plate 111. Finally, the head unit is completed by heating and pressing pins 116C. Ink Tank Unit: In Fig. 5, a component 211 is an ink fluid reservoir forming a body of the ink tank unit, a component 215 is an ink fluid absorber, a component 216 is an ink tank cover, a component 212 is an electrode pin for detecting the amount of ink fluid in the ink fluid reservoir and components 213 and 214 are contacting members in responsive to the electrode pin 212. The ink fluid reservoir 211 has a member 220 used for mounting the pin 212, the contacting members 213 and 214, and used for mounting the above mentioned head unit IJU, a supply port 231 for accepting the ink supply tube part 116A, and a lever 201, as well as a hollow cylinder part 233 standing almost at the center of the bottom of the ink fluid reservoir as shown in Fig. 5. This ink fluid reservoir 211 can be formed by molding synthetic materials in a single body. The bottom side of the hollow cylinder 233 is opened in supplying ink fluid into the ink fluid reservoir 211 and after the ink fluid reservoir 211 is filled with ink fluid, the bottom side of the hollow cylinder 233 is closed with a cap 217 shown in Fig. 5. The inside space of the hollow cylinder 233 is used as a buffer part for preventing ink fluid leakage due to vibration and movement applied to the ink tank reservoir 211. And furthermore, as the spiral channel 233 makes the air route to the air duct port 203 longer, it will be appreciated that ink fluid leakage can be effectively prevented. Figs. 6 and 7 are perspective views of an ink jet cartridge shown in Figs. 4 and 5 with a cap of one embodiment of the present invention; Fig. 6 shows the case that the cap is installed, and Fig. 7 shows the case that the cap is removed. As shown in Figs. 6 and 7, the cap 2 is made of synthetic materials and the cap 2 is composed of a holder 21 which is shaped in an open square and has an L-shaped arm at the center of the holder 21 and of a contacting member 20 supported by the holder 21. When the cap 2 is installed on the ink fluid ejection part 101, the top part 21D of the L-shaped arm standing from the center of the cap 2 touches the upper face of the ink absorber 104 placed above the ink fluid ejection part 101. And a square-shaped protruding part 21C formed below the one side of the holder beam extended horizontally touches a part of the base plate 111. So far, the cap 2 can be fixed in the vertical direction shown in Fig. 6. In Fig. 6, small protruding parts 21B and 21F formed at respective side of the holder beam extended horizontally are caught by the channels 16a and 16b, not shown in Fig. 6, both channels 16a and 16b formed at both sides of the ink fluid ejection part 101. And furthermore, an L-shaped protruding part 21E extended from one side of the holder beam extended horizontally where the small protruding part 21F is formed is locked at the corner formed beside the ink fluid ejection part 101. So far the cap 2 can be fixed in the horizontal direction shown in Fig. 6. As a result, it will be appreciated that the cap 2 is protected from being dropped or displaced while transporting the ink jet cartridge. And furthermore, the relationship between the distance between the protruding parts 21B and 21F and the contacting member 20 and the distance between the orifice disposed face 113e to which the contacting member 20 contacts and the channels 16a and 16b is determined adequately. With this determination of distance relationship, when the protruding parts 21B and 21f are caught by the channels 16a and 16b, the orifice disposed face 113e is pressed by the contacting member 20 as described later. In the case that the cap 2 is removed from the ink fluid ejection part 101, the one holder beam of the holder 21 is displaced outside by pulling a handle portion 21A. The handle portion 21A may be bent at an angle of 45°-90° relative to the holder beam. So far, the cap 2 can be easily removed even if the cap 2 is securely fixed to the ink fluid ejection part 101. In addition, since the cap 2 can be removed from the ink fluid ejection part 101 only when the handle portion 21A is pulled, the cap can be protected from being dripped by a shock at transportation. Fig. 8 shows a case that the contacting member 20 of the cap 2 is put away from the orifice disposed face 113e. Fig. 9 shows a case that the contacting member 20 of the cap 2 touches the orifice disposed face 113e. Figs. 8 and 9 are magnified cross-sectional views of the cap 2 and the major part of the recording head unit, each view projected in the direction of the arrow S shown in Fig. 6. As shown in Figs. 8 and 9, the contacting member 20 is supported by a latch 21G formed at the center side of the holder 21 and by two latches 21H formed at the other side of the holder 21. Materials used for the contacting member 20 are supposed to be elastic materials including rubbers such as nytril rubber, silicon rubber, fluorine rubber and urethane rubber, or thermal-plastic elastomers, the hardness of which is preferred to be less than or equal to 80 shore A [80° in JIS A] and to maintain its own shape and not to be adhesive. Furthermore, the materials for the member 20 is preferred to be ink-resisting. As shown in Figs. 8 and 9, the cross-sectional shape of the orifice disposed face 113e is unsymmetrical concave arc and this concave shape is extended upward and downward in a designated length in the vertical direction relative to the figure plane. The half-moon-shaped contacting part 20A of the contacting member 20 is extended upward and downward in an identical length to that of the orifice disposed face 113e in the vertical direction relative to the figure plane. The concave shape of the orifice disposed face 113e is determined in the following reasons. In case that an orifice is formed on the orifice plate 113A, the orifice 113i is so fabricated by applying laser beams. In order to fabricate the orifice 113i efficiently by laser beams, the orifice disposed face 113e and its axis are tilted in relative to the fluid path. In order that the distance between the orifice disposed face 113e so tilted and the recording medium is selected to be an adequate value and that the pressing force developed by the pressing spring 114 (shown in Fig. 5) is effectively utilized, an end part of the tilted orifice disposed face 113e far from the recording medium, which is shown in the left side of Fig. 8, is displaced forward, and the other end part of the tilted orifice disposed face 113e near the recording medium, which is shown in the right side of Fig. 8, is displaced backward. As a result, as shown in Fig. 8, the shape of the orifice disposed face 113e is a half-moon-shaped concave. The unsymmetrical concave shape of the cross-section of the orifice disposed face 113e is determined by considering the direction in which the before mentioned blade wipes the orifice disposed face 113e and by considering the relative positions of the absorber 104 for cleaning this blade and the orifice disposed face 113e. So determined the cross-sectional shape of the orifice disposed face 113e, the efficiency of wiping the orifice disposed face 113e by the blade is attained to be high. The position of the contacting part 20A when contacting the orifice disposed face 113e is selected so that the top of the circle of the half-moon-shaped contacting part 20A goes to the deepest point of the orifice disposed face 113e. By means that the contacting part 20A contacts the deepest point of the orifice disposed face 113e, it will be appreciated that a pressing force can be prevented from being applied directly to a part where the orifice 113i which does not have an enough structural rigidity is placed. And furthermore, the pressing force is applied to the deepest point of the orifice disposed face 113e, a uniform pressing force can be established on the whole face of the orifice disposed face 113e. In the orifice disposed face 113e, the orifice 113i is shifted from this deepest point of the arc. Owing to this configuration, the efficiency of wiping the orifice disposed face 113e by the blade is attained to be high, too. When the contacting part 20A contacts the orifice disposed face 113e, the orifice 113i can be sealed tightly by means that the contacting part 20A is deformed by the force developed by the channels 16a and 16b on the side face of the ejection part 101 catching the above mentioned protruding parts 21B and 21F of the holder 21. That is, as the contacting part 20A has a half-moon-shaped cross-section, the press force can be developed almost uniformly against the orifice disposed face 113e. And hence, the contacting part 20A can be deformed almost uniformly in the concave shape in responsive to the concave shape of the orifice disposed face 113e. So far, the contacting part 20A can seal tightly the orifice 113i. A preferred shape of the contacting part 20A is also supposed to be a half-oval as well as a half-moon shape. The shape of the contacting part 20A is not limited to these shapes but may be selected to be optimal one in relative to the shape of the orifice disposed face 113e. In case of using a half-moon or half-oval shaped member for the contacting part 20A, its curvature radius is a little smaller than that of the concave shape part of the orifice disposed face. In this embodiment, the amount Of deformation of the contacting part 20A is about 0.5 mm, which is within a favorable range between 0.3 mm and 0.9 mm. As described above, in this embodiment, as the orifice 113i and its neighboring area can be sealed tightly with the contacting part composed of elastic and deformable materials, in sealing the orifice 113i, a uniform press force can be developed and the shape of the contacting part can be deformed to be an identical shape to the shape of the orifice disposed face 113e. As a result, the orifice 113i and its neighboring area can be sealed tightly. The channels 20D which are formed in the contacting member 20 and which extend along the array of the orifices 113i are so designed that the elastic deformation of the contacting member 20 may be adequate and that deformation of the contacting member 20 in its installation and easiness of installation may be considered. Though in the above mentioned embodiment, the shape of the orifice disposed face sealed tightly by the cap of the present invention is selected to be an unsymmetrical concave shape, it will be appreciated that, in case of using a flat-shaped orifice disposed face 113e, an effective sealing of the orifice disposed face can be attained. In this case, desirable and tight sealing of the orifice disposed face 113e or its neighboring area can be established by means that the top of the contacting part 20A is positioned to a designated position of the orifice 113i. Figs. 10 and 11 are a perspective view and a plan view showing a container storing the above mentioned ink jet cartridge as shown in Figs. 4 and 5, respectively. The ink jet cartridge is transported and stored within the container. The container of this embodiment is also used as a holder of the contacting member described in the above embodiment. That is, as shown in Figs. 10 and 11, the contacting member 20, which is formed similarly to that of the above mentioned embodiment shown in Figs. 8 and 9, is mounted within a part of the container 2100. When storing the ink jet cartridge into the container 2100, the orifice disposed face 113e contacts the contacting member 20 and tight sealing of the orifice is established. Within the container 2100, a cylindrical-shaped protruding part 2100A is formed, which is used as a positioning member when the ink jet cartridge is installed and stored in the container 2100. In addition, this cylindrical-shaped protruding part 2100A functions in such manner that the orifice disposed face 113e of the ink jet cartridge installed in the container 2100 pushes the contacting member 20 because the distance between the contacting member 20 and the cylindrical-shaped protruding part 2100A is less than the length of the corresponding portion of the cartridge. So far, in installing the ink jet cartridge into the container 2100, tight sealing of the orifice disposed face 113e can be established. The protruding part 2100A is linked with the hole 2200B formed in the cover 2200 of the container when the cover 2200 is closed so that the cover 2200 is fixed with the container 2100. In Fig. 10, components 2100B are convex portions for positioning the ink jet cartridge installed within the container 2100. Fig. 12 is a plan view of the other embodiment of the above mentioned container. As shown in Fig. 12, the container 2100 has an inner structure adjusted for the shape of the ink jet cartridge. In this container 2100, the contacting member 20 for sealing the orifice disposed face is also formed. A component 2100B is a hole for fixing the cover, and a cylindrical-shaped protruding part to be linked with the hole 2100B is formed in the container cover, not shown in Fig. 11. Shapes of the contacting member and the orifice disposed face may not be limited to those described in the above embodiments. That is, the contacting member of the present invention can be elastically deformed in responsive to the shape of the orifice disposed face so that tight sealing of the orifice disposed face may be established. Fig. 13 is a perspective view of an ink jet recording apparatus using the above mentioned ink jet cartridge. The ink jet recording apparatus of Fig. 13 is a full-color serial type printer which have exchangeable ink tanks, each of which corresponds to ink colors of black (Bk), cyan (C), magenta (M) and yellow (Y). As an example, the ink jet head of this embodiment has 128 pieces of orifices and gives a recording density of 400 dots per inch with a driving frequency 4KHz for ejecting ink fluid periodically. In Fig. 13, components IJC are four ink jet cartridges, each cartridge corresponding to each individual ink color, yellow, magenta, cyan or black. The ink jet cartridge is formed in a unit containing a recording head unit, and an ink tank unit storing ink fluid to be supplied to the recording head unit. The ink jet cartridge IJC is mounted on the carriage so that the ink jet cartridge IJC may be removable for the carriage with a structure not shown in Fig. 13. The carriage 82 is supported on the guide rail 811 so that the carriage 82 can move along the guide rail 811, and the carriage 82 is connected to a part of a drive belt 852 driven by a main scan motor not shown in Fig. 13. Owing to this structure, the ink jet cartridge IJC can move along the guide rail 811. Components 815, 816, 817 and 818 are transport rollers placed to be parallel to the guide rail 811; transport rollers 815 and 816 are placed behind the guide rail 811, and transport rollers 817 and 818 are placed in front of the guide rail 811. Transport rollers 815, 816, 817 and 818 are driven by a sub scan motor in order to supply a recording medium P. The recording medium P is supplied forward to the orifice disposed face of the ink jet cartridge IJC so as to establish a recording face on the recording medium P. An ejection recovery unit is placed in relative to the region in which the ink jet cartridge IJC can move and the recording of information onto the recording medium is not given. In the recovery unit, a component 8300 is a cap unit corresponding to each recording head of the ink jet cartridge IJC. In responsive to the movement of the carriage 82, the cap unit 8300 can move in the horizontal direction in Fig. 13, and move in relative to the movable region of the ink jet cartridge IJC. When the carriage 82 is located at the home position, the cap unit 8300 moves forward to the recording head and contacts the recording head, and finally covers the orifice disposed face. In the recovery unit, a component 8401 is a blade used as a wiping member. In addition, a component 8500 is a pump unit evacuating ink fluid from the orifice of the recording head and its neighboring area through the cap unit 8300. In the above described embodiment, disclosed is a cap structure where a seal tape is not used between the contacting member of the cap and the orifice disposed face. It will be appreciated that the case that a seal tape is used in the cap of the present invention may give the similar advantage to that of the present invention. Figs. 14 and 15 shows a case that a seal tape is used in a cap structure shown in Figs. 8 and 9. As shown in Fig. 14, a seal tape 20c is shaped and bonded on the orifice disposed face 113e prior to installing cap 2 in the recording head. And furthermore, as shown in Fig. 15, when the cap 2 is installed in the recording head, the pressing member 20A presses the seal 20c against the orifice disposed face. So far, in the cap structure of the present invention, the pressing force developed by the cap can be applied effectively and uniformly onto the seal 20c, and hence, the sealing of the orifice 113i by the seal 20c can be established effectively. 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 the 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; 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 thermoelectric 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, as an output device of a facsimile apparatus having a transmission and receiving function, and as an output device of an optical disc apparatus for recording and/or reproducing information into and/or from an optical disc. These apparatus requires means for outputting processed information in the form of hard copy. Fig. 16 schematically illustrates one embodiment of a utilizing apparatus in accordance with the present invention to which the ink jet recording system shown in Fig. 13 is equipped as an output means for outputting processed information. In Fig. 16, reference numeral 10000 schematically denotes a utilizing apparatus which can be a work station, a personal or host computer, a word processor, a copying machine, a facsimile machine or an optical disc apparatus. Reference numeral 11000 denotes the ink jet recording apparatus (IJRA) shown in Fig. 13. The ink jet recording apparatus (IJRA) 11000 receives processed information form the utilizing apparatus 10000 and provides a print output as hand copy under the control of the utilizing apparatus 10000. Fig. 17 schematically illustrates another embodiment of a portable printer in accordance with the present invention to which a utilizing apparatus such as a work station, a personal or host computer, a word processor, a copying machine, a facsimile machine or an optical disc apparatus can be coupled. In Fig. 17, reference numeral 10001 schematically denotes such a utilizing apparatus. Reference numeral 12000 schematically denotes a portable printer having the ink jet recording apparatus (IJRA) 11000 shown in Fig. 13 is incorporated thereinto and interface circuits 13000 and 14000 receiving information processed by the utilizing apparatus 11001 and various controlling data for controlling the ink jet recording apparatus 11000, including hand shake and interruption control from the utilizing apparatus 11001. Such control per se is realized by conventional printer control technology. A cap (2) installed in an ink jet recording head (IJU) for sealing an ink ejection orifice (113i) of the ink jet recording head (IJU) comprises a contacting member (20) and a pressing structure (2, 21B, 21F, 16a, 16b). The contacting member (20) is a member having an elastically deformable convex part (20A) which contacts a face (113e) on which the orifice (113i) is disposed and seals the orifice (113i). The pressing structure (2, 21B, 21F, 16a, 16b) presses the convex part (20A) of the contacting member (20) toward the face (113e) in responsive to installing the cap (2).

Claims: Cap (2) installable in an ink jet recording head for sealing a face (113e) of said ink jet recording head with an ink ejection orifice (113i), said cap (2) comprising an elastically deformable contacting member (20) characterized in that said contacting member (20) has a convex part (20A) contactable to and pressable toward said face (113e) to which said ejection orifice (113i) is disposed by a pressing means (2, 21B, 21F, 16a, 16b) when said cap is installed and said convex part (20A) is able to be in contact with a plurality of ink ejection orifices (113i) with pressure. Cap (2) as claimed in claim 1, characterized in that said convex part (20A) is shaped in a curve. Cap (2) as claimed in claim 1 or 2, characterized in that said pressing means (2, 21B, 21F, 16a, 16b) comprises a coupling member for coupling with said ink jet recording head in said installation and for pressing said convex part (20A) of said contacting member (20) toward said face (113e) by means of said coupling member. Cap (2) as claimed in any of the preceding claims, characterized in that said convex part (20A) of said contacting member (20) is composed of a rubber material, said material having a hardness less than or equal to 80 sh A (80° of JIS A). Container (2100) comprising an elastically deformable contacting member (20) having a convex part (20A) and containing an ink jet recording head stored therein characterized in that said convex part (20A) is contacted to and pressed toward a face (113e) of said ink jet recording head having an ink ejection orifice (113i) by a pressing means. Container (2100) as claimed in claim 5, characterized in that said convex part (20A) is shaped in a curve. Container (2100) as claimed in claim 5 or 6, characterized in that said pressing means (2, 21B, 21F, 16a, 16b) has a coupling member for coupling with said ink jet recording head in said installation and for pressing said convex part (20A) of said contacting member (20) toward said face (113e) by means of said coupling member. Container (2100) as claimed in any of the claims 5 to 7, characterized in that said convex part (20A) of said contacting member (20) is composed of a rubber material, said material having a hardness less than or equal to 80 sh A (80° of JIS A). Ink jet recording head for ejecting ink comprising a cap (2) for sealing an ink ejection orifice of said ink jet recording head, wherein said cap (2) is removably installed in said ink jet recording head comprising a contacting member (20), characterized in that said contacting member (20) has an elastically deformable convex shaped part (20A) contactable to and pressable toward said face, in which said ejection orifice (113i) is formed, by a pressing means when said cap (2) is installed, a plurality of said ink ejection orifices (113i) are formed on a face (113e) of said ink jet recording head, and said convex part (20A) is able to be in contact with said plurality of ink ejection orifices (113i) with pressure. Ink jet recording apparatus as claimed in claim 9, characterized in that said convex part (20A) is shaped in a curve. Ink jet recording head as claimed in claim 9 or 10, characterized in that said face in which said ink ejection orifice (113i) is formed has a concave shape. Ink jet recording head as claimed in any of the claims 9 to 11, characterized in that said pressing means has a coupling member coupling with a coupling part of said ink jet recording head in said installation for pressing said convex part (20A) of said contacting member toward said face by means of said coupling member. Ink jet recording head as claimed in any of the claims 9 to 12, characterized in that said recording head generates a bubble in ink by means of thermal energy and ejects ink in response to the generation of said bubble.

Inventors: ABE TSUTOMU, ABE, TSUTOMU
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1992
Main classification: B41J2
IPC codes: B41J2