JP5377281B2 - Ink supply pump and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink supplying pump capable of suppressing an increase of ink consumption when recovering discharge, and also to provide an inkjet recorder provided with the pump. <P>SOLUTION: A syringe 11 for supplying ink is equipped with: a cylinder 13; a piston 15 to be pulled and pushed while being inserted into the cylinder 13; an ink sucking flow path 17 through which ink is sucked into a space S surrounded by the cylinder 13 and the piston 15 by the pulling operation; an ink push-out flow path 19 through which air remaining in the space S is discharged from the space S by pushing operation; and an ink push-out flow path 21 through which ink is pushed out from the space S by the pushing operation so as to supply the ink to a recording head 45. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an ink supply pump for supplying ink to a recording head of an ink jet recording apparatus, and an ink jet recording apparatus including the same.

  A recording head in an ink jet recording apparatus has a plurality of nozzles that eject ink. In this recording head, the ink may thicken at the nozzle and the nozzle may become clogged, so the ink is forcibly ejected from the nozzle to discharge the thickened ink, foreign matter, bubbles, etc. clogged in the nozzle. Operation (purge operation) is performed.

  Patent Document 1 discloses a recording liquid supply apparatus using a syringe as a means for forcibly ejecting ink during the ejection recovery operation. In this recording liquid supply device, the piston is pulled to create a negative pressure in the cylinder to suck ink from the ink tank into the cylinder, pressurize the sucked ink by pushing the piston, push it out of the cylinder, and supply it to the recording head. To do.

JP 2005-144710 A

  However, the ink is empty in the cylinder at the time of initial ink filling such as when the product is shipped, and a certain amount of air exists. In this state, when the ink is initially filled in the cylinder by the pulling operation of the piston, not only ink but also air remains in the cylinder. Further, during use of the ink jet recording apparatus, air contained in the ink may collect in the cylinder and form bubbles.

  In this way, even when trying to pressurize the ink by pushing the piston while air remains in the cylinder, this pressure is absorbed by the air remaining in the cylinder. Ink may not be sufficiently pressurized. In this case, since the ink pressure is not sufficiently applied to the nozzles of the recording head, the ejection recovery effect is reduced. When the discharge recovery effect is reduced, the amount of ink consumed at the time of discharge recovery increases.

  Accordingly, the present invention has been made in view of the above points, and an object of the present invention is to provide an ink supply pump that can suppress an increase in ink consumption during ejection recovery, and an ink jet recording apparatus including the same. It is to provide.

  The present invention is an ink supply pump for supplying ink to a recording head of an ink jet recording apparatus. In this ink supply pump, ink is sucked by the pulling operation into a casing, a movable member that can be pushed and pulled while being arranged in the casing, and a space surrounded by the casing and the movable member. An ink suction portion serving as a path to be discharged, an air discharge portion serving as a path through which air remaining in the space is discharged from the space by the pressing operation, and the pressing operation to supply ink to the recording head. And an ink push-out section serving as a path through which ink is pushed out of the space.

  In this configuration, in addition to the ink suction portion that becomes a path through which ink is sucked into the space by the pulling operation and the ink push-out portion that becomes a path by which the ink is pushed out from the space by the pushing operation, the ink remains in the space. An air discharge portion serving as a path through which air is discharged from the space by the pushing operation is provided. Therefore, after the ink is sucked into the casing from the ink suction portion, the air remaining in the casing can be discharged from the air discharge portion by the pushing operation of the movable member. As a result, the ink can be sufficiently pressurized in the ejection recovery operation, so that the ink can be supplied to the nozzles of the recording head with a sufficient pressure. Therefore, since it is possible to suppress a decrease in the discharge recovery effect due to the remaining air as in the conventional case, it is possible to suppress an increase in the amount of ink consumed during discharge recovery.

  Further, for example, when monochrome printing is being performed, there are recording heads that are not used. In this recording head, the ink may thicken slightly at the nozzles. In such a case, a very small amount of purging is performed in which a smaller amount of ink is ejected than in the above-described ejection recovery operation. During such a small amount of purge, since the amount of ink discharged is small, it is particularly susceptible to the influence of air remaining in the casing, and the purge effect tends to decrease. Therefore, the present invention can effectively suppress a decrease in the discharge recovery effect at the time of the above minute purge.

Further, the casing is a cylindrical cylinder having an opening in the upper part and provided with the ink suction part and the ink pushing part in the lower part, and the movable member moves upward and downward A piston having a sliding portion that is in sliding contact with the inner surface of the casing during the pulling operation, and a rod-like portion that extends upward from the sliding portion and protrudes from the opening to the outside of the casing; the air discharge unit, Ru through hole der communicating with the space with penetrating the sliding portion and the rod-like portion from the lower surface of the sliding portion to the upper surface of the rod-like portion.

  In this configuration, the pushing operation and the pulling operation of the movable member are performed along the vertical direction, the air discharge portion is a through-hole that vertically penetrates the movable member, and the ink suction portion and the ink push-out portion are provided in the lower portion of the casing. It has been. Therefore, in the casing, ink is sucked or pushed out at the lower part of the casing, while the air accumulated in the upper part of the space can be discharged upward through the through hole of the movable member. In this way, the ink and air can be divided into upper and lower parts in the casing so that the air can be efficiently discharged.

  Further, the ink jet recording apparatus of the present invention includes the ink supply pump, driving means for pushing and pulling the movable member, an ink tank for storing ink, the ink tank, and the ink suction portion. A first flow path that can be opened and closed, a recording head that is supplied with the ink extruded from the ink push-out section, a second flow path that can be opened and closed that connects the ink push-out section and the print head, Openable and closable third flow path having one end connected to the air discharge unit, the driving means, the opening and closing operation of the first flow path, the opening and closing operation of the second flow path, and the opening and closing operation of the third flow path And a control means for controlling. The control means opens the first flow path, closes the second flow path and the third flow path, and pulls the movable member so that ink in the ink tank passes through the ink suction portion. The drive means is controlled to be sucked into the space, the first flow path and the second flow path are closed, and the third flow path is opened, and the movable member is pushed to operate the space. The driving means is controlled so that air remaining in the space is discharged from the space through the air discharge portion.

  In this configuration, the air in the casing is controlled by controlling the driving means, the opening / closing operation of the first channel, the opening / closing operation of the second channel, and the opening / closing operation of the third channel as described above. Can be discharged.

  Moreover, it is preferable that the other end of the third flow path is connected to the ink tank so that ink discharged together with the air from the air discharge portion can be collected in the ink tank.

  In this configuration, even when a small amount of ink is discharged together with air from the air discharge portion, the ink can be collected in the ink tank, so that waste of ink can be saved.

  As described above, according to the present invention, it is possible to suppress an increase in ink consumption during ejection recovery.

It is sectional drawing which shows the syringe for ink supply concerning one Embodiment of this invention. It is a block diagram which shows the principal part of the inkjet recording device concerning one Embodiment of this invention provided with the syringe for ink supply of FIG. It is a front view which shows the syringe for ink supply of FIG. 1, and its drive mechanism. (A)-(c) is sectional drawing which shows discharge recovery operation | movement.

  Hereinafter, an ink supply syringe as an ink supply pump according to an embodiment of the present invention and an ink jet recording apparatus including the same will be described in detail with reference to the drawings.

<Syringe for ink supply>
As shown in FIG. 1, the ink supply syringe 11 of this embodiment includes a cylinder 13 as a casing, a piston 15 as a movable member, an ink suction channel 17 as an ink suction portion, and an air discharge portion. An air discharge channel 19 and an ink extrusion channel 21 as an ink extrusion unit are provided.

  The cylinder 13 is a hollow member having a cylindrical body portion 13a, a bottom plate 13b provided at the lower end of the body portion 13a, and a top plate 13c provided at the upper end of the body portion 13a. Arranged along the direction. An opening 13d is provided at the center of the top plate 13c.

  The piston 15 is inserted into the hollow of the cylinder 13, and can be pushed and pulled along the cylinder 13. The piston 15 includes a sliding portion 15a that is in sliding contact with the inner surface of the cylinder 13 during the pushing operation downward and the pulling operation upward, and extends upward from the sliding portion 15a. It has a rod-like portion 15b protruding outside the cylinder 13, a flange portion 15c provided at the upper end of the rod-like portion 15b, and a cylindrical portion 15d extending upward from the vicinity of the center of the flange portion 15c. The rod-like portion 15b is restrained from lateral shaking during the pushing operation and the pulling operation by the top plate 13c of the cylinder 15.

  A space S is formed by the lower surface of the sliding portion 15a and the inner surface of the cylinder 13 positioned below the lower surface. The sliding portion 15a has a flat disk shape and is formed of an elastic member such as synthetic rubber. The outer diameter of the sliding portion 15a is substantially the same as or slightly larger than the inner diameter of the cylinder 13. Thereby, it is possible to prevent the ink stored in the space S from leaking upward from the sliding portion 15 a through the space between the sliding portion 15 a and the inner surface of the cylinder 13 during the pushing operation and the pulling operation of the piston 15.

  The bottom plate 13b of the cylinder 13 is provided with a cylindrical portion 13e and a cylindrical portion 13f that extend downward. A through-hole extending in the vertical direction and communicating with the space S is formed inside the cylindrical portion 13 e, and this through-hole functions as the ink suction channel 17. That is, the ink suction channel 17 becomes a path through which ink is sucked into the space S by the pulling operation of the piston 15. In addition, a through-hole extending in the vertical direction and communicating with the space S is formed inside the cylindrical portion 13 f, and this through-hole functions as the ink push-out channel 21. That is, the ink push-out channel 21 is a path through which ink is pushed out of the space S by the pushing operation of the piston 15.

  The air discharge passage 19 extends from the lower surface of the sliding portion 15a to the upper end of the cylindrical portion 15d through the rod-like portion 15b and the flange portion 15c, and penetrates the sliding portion 15a, the rod-like portion 15b, the flange portion 15c, and the cylindrical portion 15d. It is a through hole. The air discharge channel 19 communicates with the space S, and becomes a path through which the air remaining in the space S is discharged from the space S by the pushing operation of the piston 15.

  As will be described later, a liquid supply pipe 31 as a first flow path is connected to the cylindrical portion 13e, a liquid supply pipe 33 as a second flow path is connected to the cylindrical portion 13f, and a third flow path is connected to the cylindrical portion 15d. A discharge pipe 35 as a flow path is connected.

<Structure of main part of inkjet recording apparatus>
An ink jet recording apparatus 41 shown in FIG. 2 is an ink jet printer capable of forming an image on a recording medium (for example, paper) based on image information received from an external computer. The recording device 41 includes an ink supply syringe 11, a driving mechanism 61 as a driving unit that pushes and pulls the piston 15 of the syringe 11, a recording head 45, and the recording head 45. An ink tank 43 for storing ink to be supplied to the recording head, a waste ink tank 47 for collecting ink discharged from the recording head 45 without being ejected from the nozzles among the ink supplied to the recording head 45, and the liquid feeding pipes 31, 33, 37, the discharge pipe 35, the control part 81, etc. are accommodated. The ink collected in the waste ink tank 47 may be returned to the ink tank 43 again.

  For example, the storage head 45 corresponding to each color of black, cyan, magenta and yellow is arranged in the casing, but only one of them is shown in FIG. Therefore, an ink tank 43, an ink supply syringe 11, a waste ink tank 47, and the like are provided for the recording heads 45 of each color.

  The liquid feed pipe 31 connects the ink tank 43 and the cylindrical portion 13e. The liquid feeding pipe 33 connects the cylindrical portion 13 f and the recording head 45. The discharge pipe 35 connects the cylindrical portion 15 d and the ink tank 43. The liquid feeding pipe 37 connects the recording head 45 and the waste ink tank 47. Specifically, the liquid feeding pipe 31 is connected to an unillustrated ink outlet provided on the lower surface of the ink tank 43. The discharge pipe 35 is connected to an ink inlet (not shown) provided on the upper surface of the ink tank 43. Solenoid valves 51, 53, 55, and 57 are disposed on the liquid feeding pipes 31, 33, and 37 and the discharge pipe 35, respectively. Thereby, the flow path of each pipe can be opened and closed.

  As shown in FIG. 3, the drive mechanism 61 includes a motor 63 having a rotating shaft 63a, a screw shaft 65 connected to the rotating shaft 63a and having a male screw on the surface, and a cup for connecting the rotating shaft 63a and the screw shaft 65 to each other. A ring 67 and a ball screw portion 71 having a through hole in which a screw shaft 65 is inserted and an internal thread is formed on the inner surface, and a support member that restricts the vertical movement of the ball screw portion 71 and supports the screw shaft 65 68, 69.

  The ball screw portion 71 extends in a substantially horizontal direction from a portion screwed to the screw shaft 65, and has a pair of sandwiching pieces 71a and 71b arranged vertically at the end thereof. These clamping pieces 71a and 71b are fixed to the flange portion 15c so as to sandwich the flange portion 15c of the piston 15 from above and below. As a result, when the motor 63 is driven, the ball screw portion 71 moves up and down between the support members 68 and 69 to push or pull the piston 15.

  In addition to the stored ink, air is also present in the upper portion of the ink tank 43. The liquid level of the ink in the ink tank 43 is adjusted to be lower than the lower end of the nozzle provided on the lower surface of the recording head 43 (water head difference).

  The control unit 81 includes a central processing unit (CPU), a memory (ROM) that stores data such as a program, and a memory (RAM) that temporarily stores data when the program is executed. The control unit 81 controls operations of the drive mechanism 61, the electromagnetic valves 51, 53, 55, 57, and the like.

<Operation of inkjet recording apparatus>
Next, the ejection recovery operation of the recording head 45 of the inkjet recording apparatus 41 will be described. FIG. 4A shows an initial state when the product is shipped in which the space S of the ink supply syringe 11 is not filled with ink. At this time, air exists in the space S.

  First, the control unit 81 controls each solenoid valve to open the solenoid valve 51 and close the solenoid valves 53, 55, and 57. In this state, the control unit 81 controls the drive mechanism 61 to rotate the motor 63 to one side to pull the piston 15. When the piston 15 is pulled, the space S and the liquid feeding pipe 31 become negative pressure, so that the ink in the ink tank 43 passes through the liquid feeding pipe 31 and the ink suction flow path 17 as shown in FIG. S is sucked into. At this time, the ink L and the air A exist above the space S.

  Next, the control unit 81 controls each solenoid valve so as to open the solenoid valve 55 and close the solenoid valves 51, 53, and 57. In this state, the control unit 81 controls the drive mechanism 61 to rotate the motor 63 to the other side to push the piston 15. When the piston 15 is pushed, the air A remaining in the upper part of the space S is discharged from the space S through the air discharge channel 19 provided in the piston 15. The discharged air A is collected in the ink tank 43 through the discharge pipe 35.

  In the discharge operation of the air A, as shown in FIG. 4C, the pushing operation of the piston 15 is continued for a while after most of the air A is discharged so that the air A does not remain in the space S. A small amount of ink L is also discharged from the space S through the air discharge channel 19. A small amount of ink L discharged from the space S together with the air A is collected in the ink tank 43 through the discharge pipe 35. As a result, the space S is almost exhausted with air A and filled with ink L.

  Next, when the amount of ink filled in the space S is more than the amount necessary for the ejection recovery operation of the nozzles of the recording head 45, the piston 15 is pushed to supply ink to the recording head 45. On the other hand, when the ink amount is less than the amount necessary for the ejection recovery operation, the piston 15 is again pulled to fill the space S with more ink. When the ink filling amount is increased, the following operation is performed.

  That is, the control unit 81 controls each solenoid valve so as to open the solenoid valve 51 and close the solenoid valves 53, 55, and 57. In this state, the control unit 81 controls the drive mechanism 61 to rotate the motor 63 to the one side to pull the piston 15. When the piston 15 is pulled, the ink in the ink tank 43 is sucked into the space S through the liquid feeding pipe 31 and the ink suction flow path 17. At this time, the space S is filled with more ink L than in the state of FIG. 4C, and there is almost no air.

  Next, ink is supplied to the recording head 45. In an initial state such as when the product is shipped, since the recording head 45 is not filled with ink, an operation of filling the recording head 45 with ink is executed first.

  That is, the control unit 81 controls each solenoid valve so that the solenoid valves 53 and 57 are opened and the solenoid valves 51 and 55 are closed. In this state, the control unit 81 controls the drive mechanism 61 to rotate the motor 63 to the other side to push the piston 15. When the piston 15 is pushed, the ink L in the space S of the ink supply syringe 11 is pushed out of the space S through the ink push-out channel 21. The ink pushed out from the space S is supplied to the recording head 45 through the liquid feeding pipe 33 and filled in the recording head 45. At this time, the air present in the recording head 45 in the initial state is pushed out by the ink and collected in the waste ink tank 47.

  Next, the space S of the ink supply syringe 11 is filled again with ink. That is, the control unit 81 controls each solenoid valve so as to open the solenoid valve 51 and close the solenoid valves 53, 55, and 57. In this state, the control unit 81 controls the drive mechanism 61 to rotate the motor 63 to the one side to pull the piston 15. When the piston 15 is pulled, the ink in the ink tank 43 is sucked into the space S through the liquid feeding pipe 31 and the ink suction flow path 17.

  Finally, ink is forcibly ejected from the nozzles of the recording head 45. That is, the control unit 81 controls each solenoid valve so as to open the solenoid valve 53 and close the solenoid valves 51, 55, and 57. In this state, the control unit 81 controls the drive mechanism 61 to rotate the motor 63 to the other side to push the piston 15. When the piston 15 is pushed, the ink L in the space S of the ink supply syringe 11 is pushed out of the space S through the ink push-out channel 21. The ink pushed out from the space S is supplied to the recording head 45 through the liquid feeding pipe 33 and is ejected from a plurality of nozzles on the lower surface of the recording head 45. The ejected ink is stored in an ink tray 46 disposed below the recording head 45 and is collected in a waste ink tank 47 through a liquid feed pipe 38. The amount of ink to be pushed out can be adjusted as appropriate by adjusting the amount by which the piston 15 is pushed down. For example, the amount of ink used for one ejection recovery operation can be about 0.1 to 10 cc. Further, the ink discharge pressure at the nozzle can be adjusted, for example, by changing the push-down speed of the piston 15. After the above series of operations is completed, the control unit 81 performs a printing operation or the like as necessary.

  As described above, in this embodiment, the ink suction flow path 17 that is a path through which ink is sucked into the space S by the pulling operation, and the ink push-out flow path 21 that is a path from which ink is pushed out from the space S by the pressing operation. In addition, an air discharge passage 19 serving as a path through which air remaining in the space S is discharged from the space S by the pushing operation is provided. Therefore, after the ink is sucked into the cylinder 13 from the ink suction flow path 17, the air remaining in the cylinder 13 can be discharged from the air discharge flow path 19 by the pushing operation of the piston 15. Thereby, in the ejection recovery operation, the ink can be sufficiently pressurized with almost no air remaining in the space S, so that the ink can be supplied to the nozzles of the recording head 45 with a sufficient pressure. Therefore, since it is possible to suppress a decrease in the discharge recovery effect due to the remaining air as in the conventional case, it is possible to suppress an increase in the amount of ink consumed during discharge recovery.

  Further, in this embodiment, the pushing operation and the pulling operation of the piston 15 are performed along the vertical direction, the air discharge channel 19 is a through-hole penetrating the piston 15 up and down, and the ink suction channel 17 and the ink extrusion A flow path 21 is provided below the cylinder 13. Accordingly, in the cylinder 13, the ink is sucked or pushed out at the lower part of the cylinder 13, while the air accumulated in the upper part of the space S can be discharged upward through the through hole of the piston 15. In this way, the air can be efficiently discharged by dividing the ink and air into upper and lower parts in the cylinder 13.

  Moreover, in this embodiment, the air in the cylinder 13 can be discharged | emitted efficiently by controlling the drive mechanism 61, the solenoid valve 51, the solenoid valve 53, and the solenoid valve 55 as mentioned above.

  In the present embodiment, the other end of the discharge pipe 35 is connected to the ink tank 43 so that the ink discharged together with the air from the air discharge channel 19 can be collected in the ink tank 43. Even when a small amount of ink is discharged from the flow path 19 together with air, the ink can be collected in the ink tank 43, so that waste of ink can be eliminated.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the pushing operation and the pulling operation of the piston are performed along the vertical direction has been described as an example, but the present invention is not limited thereto. For example, it may be performed along a direction such as a direction in which the piston is inclined with respect to the vertical direction or a horizontal direction.

  Moreover, although the said embodiment gave and demonstrated the case where the cylinder was cylindrical shape, another shape may be sufficient.

  Moreover, although the said embodiment gave and demonstrated the case where the air discharge part was a through-hole which penetrates the inside of a piston, it is not limited to this. For example, the air discharge part may be provided in the cylinder.

  In the above embodiment, the case where the movable member is a piston having a sliding portion and a rod-like portion has been described as an example. However, other members such as a plunger may be used.

  In the above embodiment, the case where a syringe is used as the ink supply pump has been described as an example. However, the present invention is not limited to this. As an ink supply pump, by changing the volume of a space formed between the casing and a movable member that is in sliding contact with the casing, the liquid can be sucked from the ink sucking portion and pushed out from the ink pushing portion, and Other positive displacement pumps having an air discharge portion for discharging the remaining air from the space by the pushing operation of the movable member can also be used.

DESCRIPTION OF SYMBOLS 11 Ink supply syringe 13 Cylinder 13a Body part 13d Opening part 13e, 13f Cylindrical part 15 Piston 15a Sliding part 15b Rod-like part 15c Flange part 15d Cylindrical part 17 Ink suction flow path 19 Air discharge flow path 21 Ink extrusion flow path 31, 33 Liquid feed pipe 35 Discharge pipe 41 Inkjet recording device 43 Ink tank 45 Recording head 51, 53, 55, 57 Electromagnetic valve 61 Drive mechanism

Claims (3)

An ink supply pump for supplying ink to a recording head of an ink jet recording apparatus,
A casing,
A movable member capable of pushing and pulling in a state of being disposed in the casing;
An ink suction portion serving as a path through which ink is sucked by the pulling operation into a space surrounded by the casing and the movable member;
An air discharge portion serving as a path through which air remaining in the space is discharged from the space by the pushing operation;
An ink extruding section that provides a path through which ink is pushed out of the space by the pushing operation in order to supply ink to the recording head ;
The casing is a cylindrical cylinder having an opening in the upper part and provided with the ink suction part and the ink extruding part in the lower part,
The movable member includes a sliding portion that is in sliding contact with the inner surface of the casing during the pushing operation downward and the pulling operation upward, and extends upward from the sliding portion, and extends from the opening to the casing. And a piston having a rod-like portion protruding outside.
The ink supply pump , wherein the air discharge portion is a through-hole that penetrates the sliding portion and the rod-shaped portion from the lower surface of the sliding portion to the upper surface of the rod-shaped portion and communicates with the space . An ink supply pump according to claim 1 ;
Drive means for causing the movable member to push and pull;
An ink tank for storing ink;
An openable and closable first flow path connecting the ink tank and the ink suction part;
A recording head to which the ink extruded from the ink extruding unit is supplied;
An openable and closable second flow path connecting the ink extruding part and the recording head;
An openable and closable third flow path having one end connected to the air discharge unit;
Control means for controlling the driving means, the opening and closing operation of the first channel, the opening and closing operation of the second channel, and the opening and closing operation of the third channel;
The control means includes
With the first flow path opened and the second flow path and the third flow path closed, the movable member is pulled and ink in the ink tank is sucked into the space through the ink suction portion. Controlling the drive means,
With the first flow path and the second flow path closed, and the third flow path opened, the movable member is pushed and the air remaining in the space is discharged from the space through the air discharge portion. An ink jet recording apparatus for controlling the driving means as described above. The inkjet recording according to claim 2 , wherein the other end of the third flow path is connected to the ink tank so that ink discharged together with the air from the air discharge portion can be collected in the ink tank. apparatus.

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