Abstract:
An ink jet apparatus has installed therein a retractable recovery device. The ink jet apparatus has a housing with a space accommodating a carriage for scanning a recording area, an ink jet head removably mounted on the carriage for ejecting ink onto a recording medium as the carriage scans the recording area, and a removable cover member forming a part of the housing covering said space. The recovery device includes a pressing member mounted in the space at a location outside the scanning area for movement between an accommodating position and an operating position. The pressing member extends from the space when moved to the operating position after removal of the cover member, whereby a recovery operation using the pressing member can be performed on the ink jet head by removing the ink jet head from the carriage. The pressing member, when in the accommodating position, is disposed within the space for concealment by the cover member.

Description:
This application is a continuation of application Ser. No. 07/831,635 filed Feb. 10, 1992, now abandoned, which in turn is a continuation of application Ser. No. 07/493,827 filed Mar. 15, 1990, now abandoned, which in turn is a continuation of application Ser. No. 07/187,987, filed Apr. 29, 1988, now U.S. Pat. No. 4,967,209, issued Oct. 30, 1990. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a recovery device used for recovery from unsatisfactory ink discharge of an ink jet recording head, an ink jet printer provided with the recovery device, and an electronic desk calculator provided with the printer. 
     2. Related Background Art 
     In an ink jet printer provided with an ink jet recording head, supply of ink from an ink chamber storing the ink therein to a discharge port for discharging the ink therethrough is accomplished mostly by the utilization of capillary phenomenon. Therefore, if air remains in the ink chamber and/or an ink passageway and bubbles are created, supply of the ink to the discharge port cannot be smoothly accomplished, and this may sometimes bring about an inconvenience for the ink discharge from the discharge port. 
     The entry of bubbles into the recording head is particularly remarkable, for example, during the filling of the ink chamber of the recording head with ink, or during the mounting of the recording head in a case where the recording head being used is of the cartridge type, or when vibrations are imparted to the printer or the printer falls and is shocked. 
     So, when the entry of bubbles into the recording head has occurred, it is necessary to remove such bubbles from the recording head to provide a good ink discharge condition. 
     Also, in the ink jet recording head, it is sometimes the case that the solvent of the ink evaporates at the ink discharge port to create solidities adhering to the discharge port of bubbles and foreign materials such as dust clog the liquid path to cause unsatisfactory ink discharge including non-discharge of ink. 
     As a method for recovering from such unsatisfactory ink discharge, there is generally adopted, for example, a method of pressing the ink chamber with the discharge port facing upward and forcing the solidities adhering to the discharge port and the foreign materials in the liquid path out of the discharge port, etc. to thereby remove them. 
     For example, in a prior-art ink jet printer  611  carried on an electronic desk calculator as shown in FIGS. 1A and 1B of the accompanying drawings, a recording head  612  is formed with a small hole (a pressing small hole)  612   a  used access an ink reservoir bag member (within which an ink chamber is formed) in the recording head, and a pressing needle  613  may be inserted into the small hole  612   a  to thereby press the ink reservoir bag member. 
     That is, means for recovery from unsatisfactory ink discharge in such apparatus comprises a flange-like portion (a cradle)  601   a  horizontally protruding from an upper cover  601  and formed with a recess  601   e , and an upright pressing needle  613  having its lower end fixed to the center of the bottom of the recess  601   e.    
     To perform the operation of recovering from the unsatisfactory ink discharge of the recording head as described above, the recording head  612  is first detached from the printer and that portion thereof in which the pressing small hole  612   a  is formed is gradually fitted into the recess  601   e . Thereupon, the recording head  612  assumes its upright state with the discharge port (not shown) facing upward, and the pressing needle  613  provided in the recess  601   e  is gradually inserted into the pressing small hole  612   a  in the recording head  612 . As the pressing needle  613  is further inserted upward, the ink reservoir bag member (the ink chamber) in the recording head  612  is gradually pressed and the ink is forced up toward the discharge port by the pressure, and the foreign materials, with the ink, are removed from the discharge port. This operation is continued, for example, until the moment when the ink leaks out of the discharge port. 
     Finally, when the ink has come to leak out of the discharge port, the recording head  612  is raised up and the pressing needle  613  is withdrawn from the pressing small hole  612   a , and the recording head  612  is held raised up for a while (so that the leaking ink may not drip). Thereupon, the ink which has leaked out onto the recording head  612  is gradually absorbed from the discharge port into the ink reservoir bag member due to the elastic force of restitution of the ink reservoir bag member. 
     When the absorption of the ink is completed, the surface tension of the ink in the discharge port portion becomes balanced with the negative pressure in the ink reservoir bag member and therefore, no air enters thereinto and the recording head becomes ready for normal use. 
     After the operation of recovery from unsatisfactory ink discharge is completed in the manner described above, an ink cartridge is set in the printer. 
     In the above-described prior-art printer, however, it is necessary that the size and shape of the flange-like portion  601   a  and the location at which it is installed be set so that a sufficient space for accommodating that portion of the recording head in which the pressing small hole  612   a  is formed may be provided in the recess  601   e  in which the pressing needle  613  is provided and moreover, during the pressing of the ink chamber, an effective operation of recovery from unsatisfactory ink discharge may be accomplished with the recording head remaining upright, for example, so that when any ink leaks out of the discharge port, it will not go into the printer. 
     However, such reguirements in the design of the flange-like portion  601   a  are great limitations on the compactness and design of the printer itself, and they are problems that need to be solved for such printer to be carried on various types of instruments such as more compact electronic desk calculators or instruments which are higher in function and fashionableness. 
     Moreover, the pressing needle  613  is always upright and therefore, meticulous care must be taken so as not to break the pressing needle  613  when handling the printer and thus, there has been the problem that hindrances sometimes occur to the operability of the printer. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a device for recovery from unsatisfactory ink discharge of an ink jet recording head which poses no limitation in the compactness and design of an ink jet printer, an ink jet printer provided with the recovery device, and an electronic desk calculator provided with the printer. 
     It is another object of the present invention to provide a device for recovering from unsatisfactory ink discharge of an ink jet recording head which does not adversely affect the operability of an ink jet printer, an ink jet printer provided with the recovery device, and an electronic desk calculator provided with the printer. 
     It is still another object of the present invention to provide an ink jet printer having an ink jet recording head having an ink chamber for storing therein ink to be supplied to a discharge port for discharging ink therethrough, and recovery means having a pressing member for pressing said ink chamber, said pressing member being capable of being contained in the body of a printer. 
     It is yet still another object of the present invention to provide a recovery device for an ink jet recording head having a pressing member for pressing the ink chamber of the ink jet recording head having an ink chamber for storing therein ink to be supplied to a discharge port for discharging ink therethrough, said pressing member being capable of being contained in the body of a printer. 
     It is yet another object of the invention to provide a recovery device in an ink jet apparatus having a housing with a space accommodating a carriage for scanning a recording area, an ink jet head removably mounted on the carriage for ejecting ink onto a recording medium as the carriage scans the recording area, and a cover member forming a part of the housing covering the space and being movable to a position exposing the space, wherein the recovery device includes a positioning member mounted in the space at a location outside the scanning area for movement between an accommodating position and an operating position, the pressing member extends from the space when moved to the operating position after movement of the cover member to expose the space, whereby a recovery operation using the pressing member can be performed on the ink jet head by removing the ink jet head from the carriage, and the pressing member is disposed within the space for concealment by the cover member when the pressing member is in the accommodating position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a schematic perspective view showing an example of the prior-art ink jet printer as carried on an electronic desk calculator. 
     FIG. 1B is a schematic enlarged cross-sectional view along the line C—C of FIG.  1 A. 
     FIGS. 2A and 2B are schematic perspective views showing an embodiment of the ink jet printer of the present invention as carried on an electronic desk calculator, FIG. 2A showing a state in which a printer lid is removed, and FIG. 2B showing a state in which the printer lid is attached to the printer. 
     FIG. 3A is a schematic enlarged perspective view of the essential portions of the ink jet printer of the present invention. 
     FIG. 3B is a schematic enlarged cross-sectional view along the line A—A of FIG.  3 A. 
     FIGS. 4A-4D are schematic top plan views showing the process of cocking up or extending a pressing needle. 
     FIG. 5 is a schematic perspective view for illustrating the operation of removing bubbles in the ink jet printer of the present invention. 
     FIGS. 6A and 6B are schematic views showing another embodiment of the portion of the ink jet printer of the present invention in which the pressing needle is installed, FIG. 5A being a schematic perspective view, and FIG. 6B being a schematic enlarged cross-sectional view along the line B—B of FIG.  6 A. 
     FIGS. 7A and 7B are schematic views showing the essential portions of an ink jet printer according to still another embodiment of the present invention, FIG. 7A being a schematic enlarged perspective view, and FIG. 7B being a schematic enlarged corss-sectional view along the line D—D of FIG.  7 A. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the printer of the present invention, a pressing needle used for the operation of recovery from unsatisfactory ink discharge of the recording head can be received in a cradle except during use and therefore, the space occupied by means for recovery from unsatisfactory ink discharge is greatly saved and the degree of freedom with which such recovery means is installed is increased and thus, the limitations in the compactness and designing of the printer by the means for recovery from unsatisfactory ink discharge as experienced in the prior-art printer can be eliminated. 
     Some embodiments of the present invention will hereinafter be described in detail with reference to the drawings. 
     FIGS. 2A and 2B are schematic perspective views showing the essential portions of an embodiment in which the ink jet printer of the present invention is carried out on an electronic desk calculator. FIG. 2A shows a state in which a printer lid or cover member  6  for opening and closing a recording head containing portion with respect to the outside is removed, and FIG. 2B shows a state in which the printer lid is attached to the printer. 
     In this embodiment, the printer body  11  is held between an upper cover  1  and a lower cover  2 , and has a recording head  12  placed on a carriage to effect printing while being moved in opposed relationship with printing paper (not shown). 
     The upper cover  1  is provided with a flange-like portion (a cradle)  1   a  rising out to the upper part of the containing portion for the printer  11  in parallelism to the bottom of the instrument body, and a groove for containing the pressing needle therein and two restraining pawls  1   b  (or engaging members) covering a part thereof are formed in the upper surface portion of the flange-like portion  1   a.    
     The aforementioned pressing needle  13  which is a pressing member used for the operation of recovery from unsatisfactory ink discharge is provided on the flange-like portion  1   a.    
     The pressing needle  13 , as shown for example in FIGS. 3A and 3B (FIG. 3A being a schematic enlarged perspective view of the essential portions of the flange-like portion  1   a  and FIG. 3B being a schematic enlarged cross-sectional view along the line A—A of FIG.  3 A), is of an inverted T-bar shape having a protruding portion (a holding portion)  13   b  orthogonal to the needle body  13   a , and is rotatably held by the holding portion  13   b  in the containing groove  1   c  for the pressing needle  13  and between the two restraining pawls  1   b  and the bottom of the containing groove  1   c.    
     The tip end portion  13   c  of the pressing needle  13 , when in its contained or restracted state, is disposed so as to slightly protrude from the flange-like portion  1   a  and is designed to be capable of acting as a hook that can be caught by a user&#39;s fingers when it is to be erected or extended for use. 
     The shape of the containing groove  1   c  and the positional relation thereof with the restraining pawls  1   b  are so set that the holding portion  13   b  is removably mountable between the restraining pawls  1   b  and the bottom of the containing groove  1   c , and the pressing needle  13  can be removably mounted into the groove  1   c  as required, or can be replaced with another pressing needle. 
     A recess corresponding in shape to the holding portion  13   b  is formed in that portion of the underside of the restraining pawls  1   b  against which the holding portion  13   b  bears, and by virtue of this recess, the holding portion  13   b  is stably held between the restraining pawls  1   b  and the bottom of the groove  1   c  without moving unduly within the groove  1   c.    
     The flange  1   a  functions as a cradle for a recording head  21  during the containment of the pressing needle  13  and the operation of recovery from unsatisfactory ink discharge, and if it has such a function, the configuration thereof is not limited as described above. Also, by making the flange-like portion  1   a  wide as shown, it can be made to function as a saucer for receiving any ink which may leak from the discharge port of the recording head  12  during the operation of recovery from unsatisfactory ink discharge, or for preventing fragments of the pressing needle  13  when damaged from entering into the instrument, and whether such a function is added to the flange-like portion can be selected in conformity with the position at which the pressing needle  13  is provided. 
     Further, in this embodiment, the flange-like portion  1   a  is provided as protruding from the upper over  1 , but alternatively may be provided at other suitable locations on the upper cover  1  or the lower cover  2 , or a suitable planar surface of a member constituting the instrument may be utilized as the flange-like portion  1   a  and a groove for containing the pressing needle may be directly formed therein. 
     The pressing needle  13 , during its non-use, is contained in the containing groove  1   c  while being brought down or retracted, and during its use, it is in its extended state with its head first extended up with the point of intersection between its body  13   a  and holding portion  13   b  as a fulcrum. 
     To press the ink reservoir bag member of the ink jet recording head  12  and perform the operation of recovery from unsatisfactory ink discharge as previously described, the recording head  12  is first removed from the carriage. Subsequently, the pressing needle  13  which is being contained is extended through the procedures as shown in the schematic top plan views of FIGS. 4A-4D. 
     That is, the head  13   c  of the pressing needle  13  being contained as shown in FIG. 4A is caught by the user&#39;s fingers or the like and extended. At this time, the pressing needle  13  is extended while its holding portion  13   b  is rotating. The two restraining pawls  1   b  are formed with portions having a spacing between each other that is somewhat narrower than the diameter of the pressing needle body  13   a  and therefore, the pressing needle  13  first bears against those portions (FIG.  4 B). 
     When a further force is applied to the pressing needle  13 , the pressing needle  13  advances while spreading the two restraining pawls  1   b  in the directions of arrows E and F indicated in FIG. 4C, and finally, as shown in FIG. 4D, it is smoothly forced into recesses  1   ba  corresponding to the diameter of the pressing needle  13  which are provided at the locations on the two restraining pawls  1   b  so that the pressing needle  13  is extended. Because the two deformed restraining pawls  1   b  try to restore their initial positions, this maintains needle  13  in a stable extended position. 
     Subsequently, the thus extended pressing needle  13  is inserted into a small pressing small hole  12   a  in the earlier removed recording head  12 , as shown in FIG. 5, and the operation of recovery from unsatisfactory ink discharge is performed in accordance with the procedures as previously described. That is, the pressing needle  13  applies pressure to the externally-accessible portion of the recording head  12  at the hole  12   a , which is located at a side of the head opposite the discharge ports. 
     While an embodiment of the present invention has been described above, the present invention is not restricted thereto, but may assume various modes of embodiment. 
     For example, as shown in FIGS. 6A and 6B, a recess  1   bb  of a polygonal cross-sectional shape such as a square, and corresponding in shape to those portions of the holding portion  13   b  which bear against the restraining pawls  1   b  (or engaging members) when the pressing needle  13  is retracted and when the pressing needle  13  is extended may be provided in the underside of each restraining pawl  1   b , and further the spacing between the two restraining pawls  1   b  is set to a value greater than the diameter of the pressing needle  13 . Thus, the stable holding of the pressing needle  13  between the restraining pawls  1   b  and the bottom of the groove  1   c  becomes possible only when the pressing needle  13  is extended (broker line) and when the pressing needle  13  is retracted (solid line), and the extending of the pressing needle  13  and the operation of letting the pressing needle  13  be retracted can be rhythmically accomplished with moderate click and with good operability. 
     The shape of the pressing needle is not limited to an inverted T-bar shape, but may be suitably selected, for example, in accordance with the configuration of the recording head to be treated if the pressing needle can be contained in the groove during its non-use and has a shape necessary for performing the operation of recovery from unsatisfactory ink discharge. 
     FIGS. 7A and 7B are schematic views showing the essential portions of an ink jet printer according to still another embodiment of the present invention. FIG. 7A is a schematic enlarged perspective view, and FIG. 7B is a schematic enlarged cross-sectional view along the line D—D of FIG.  7 A. 
     This embodiment differs from the embodiment shown in FIG. 3 in that electrodes  14   a  and  14   b  are provided on the bottom of the pressing needle  13  and the wall of the containing groove, respectively, and detecting means (not shown) for detecting the contact between those electrodes  14   a  and  14   b  is further provided. In the present embodiment, the electrodes  14   a  and  14   b  are designed to contact each other when the pressing needle  13  is in its extended state as shown in FIG.  7 B. Further, in the present embodiment, when said contact is detected by said detecting means, the ink jet recording head is stopped from operating. In such an embodiment, recording can be prevented from being effected with the pressing needle remaining extended and therefore, the ease with which the ink jet printer can be further improved. 
     In the embodiments described above, the pressing needle can be extended and retracted so that the pressing needle can be contained in the printer body, but the present invention is not restricted thereto. For example, the pressing needle may be designed to be insertable into the printer body while remaining extended so that the pressing needle can be contained in the printer body. 
     In the printer of the present invention, the pressing needle used for the recovery from the unsatisfactory ink discharge of the recording head is designed to be capable of being contained in the cradle except during recovery, whereby the space occupied by the means for recovery from unsatisfactory ink discharge can be greatly saved and the degree of freedom with which such means is located is increased, and the limitations in the compactness and design of the printer caused by the means for recovery from unsatisfactory ink discharge that have been problematic in the prior-art printer can be eliminated.