JPH09287575A - Liquid pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid pump which simplifies a structure of a flow passage for reducing fluid resistance during a charging process bringing about efficient charging, and blocks a suctioning port side and a discharge port side inside a cylinder bringing about efficient suctioning and discharging. SOLUTION: A linear through-hole 5d is formed on a sliding body 5 independently on a hole through which a piston shaft 4' is inserted in the moving direction of a piston shaft 4. During a charging process where the piston shaft 4 slides against an inner wall of a cylinder 3, the through-hole 5d serves as a fluid passage with a simple structure having no corners. Fluid resistance is suppressed to minimum for preventing contraflow of the fluid bringing about efficient charging. During suctioning process, the through-hole 5d is blocked by means of a pressing part 4b, and a suctioning side ink chamber 7 and a discharging side ink chamber are blocked. The liquid is efficiently suctioned from a suctioning port 1, and discharged from a discharging port 2. Liquid supply is stabilized and its reliability is kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid pump, and more particularly, to a liquid pump for use in a liquid jet recording apparatus such as an ink jet recording apparatus or the like for maintaining reliability of ink supply.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, a head liquid chamber is initially filled with an appropriate amount of ink and then continuously replenished. Further, ink clogging in an ink supply path is prevented, An ink suction pump is used as a reliability maintaining mechanism that eliminates air bubbles mixed in the ink.

FIG. 11 is a cross-sectional view of a main part for explaining a main part of an ink suction pump according to the prior art. This ink suction pump has an ink suction port 1 at one end and the other end. A cylinder 3 having a discharge port 2, a piston shaft 4 that reciprocates in the cylinder 3, and a slide body 5 that is reciprocated by the piston shaft 4 on the inner wall surface of the cylinder 3 reciprocate the piston shaft 4. Accordingly, when the piston shaft 4 is moved in the direction of arrow A (filling stroke), the sliding body 5 is brought into contact with the sliding body regulating portion 4a provided on the piston shaft 4 and pulled by the sliding body regulating portion 4a. In this way, the sliding body moving portion slides on the inner wall surface of the cylinder 3 and, as shown,
A gap 5a is opened between the sliding member 4b and the sliding body 5, and the volume of the suction side ink chamber 6 is reduced to increase the liquid pressure through the gap 5b with the piston shaft 4, and the volume of the discharge side ink chamber 7 is increased to increase the liquid. The pressure is reduced, and accordingly, the ink in the suction-side ink chamber 6 flows into the discharge-side ink chamber 7 through the gaps 5b and 5a.

Contrary to the above-described filling stroke, when the piston shaft 4 is moved in the direction of arrow B (suction stroke), the sliding body 5
The through hole 5c is closed and pushed by the pushing portion 4b provided on the piston shaft 4, and the suction port side ink chamber 6 and the discharge port side liquid chamber 7 are
Are closed, the volume of the suction side ink chamber 6 is increased to lower the liquid pressure, and a corresponding amount of ink is sucked from the suction port 1, and at the same time, the volume of the discharge side ink chamber 7 is reduced. The liquid pressure is increased by ejecting the ink in the ejection side ink chamber 7 from the ejection port 2. In this way, ink is supplied to the head liquid chamber by alternately repeating the filling process and the suction process.

As described above, in the above-mentioned ink suction pump, ink can be supplied to the head liquid chamber simply by repeating the reciprocating motion of the piston shaft without using a special valve. In this sense. , JP-A-7-189922
Ink suction pump described in Japanese Patent Laid-Open No. 3-5160, ink suction pump described in Japanese Patent Laid-Open No. 3-5160, and Japanese Patent Publication No. 51-261.
The liquid pump described in Japanese Patent Publication No. 65 is also based on the same principle.

As described above, in the case of an ink suction pump that does not use a special valve, the backflow of ink is suppressed to a minimum during the filling process, and the ink is efficiently filled. Good inhalation and exhalation is desirable. Particularly, in an ink suction pump as a reliability maintaining mechanism of an ink jet recording apparatus, ink is efficiently filled by minimizing backflow of ink, and ink is efficiently sucked and discharged, and ink is ejected from the head liquid chamber. It is very important to supply a stable supply to.

[0007]

However, as is clear from the above description, in the case of the ink suction pump according to the prior art, the structure of the ink flow path has a plurality of structures during the filling process (movement in the direction A). Since it has a complicated structure with a bend angle, this becomes a fluid resistance, and the ink flows backward and is not efficiently filled. Further, during the suction stroke (moving in the B direction), the pushing portion of the piston shaft and the sliding body do not come into close contact with each other, leaving a gap, and the ink is not sucked and discharged efficiently. This also applies to the ink suction pump described in JP-A-7-189922, the ink suction pump described in JP-A-3-5160, and the liquid pump described in JP-B-51-26165. , Is a common problem.

In view of the above-mentioned situation, the present invention prevents backflow of ink during the filling process and allows efficient filling, and the suction port side and the discharge port side inside the cylinder during the suction process. It is an object of the present invention to provide an ink suction pump that is capable of efficiently sucking and discharging ink by blocking the ink and efficiently exerting a function as a reliability maintaining mechanism of ink supply.

[0009]

According to a first aspect of the present invention, there is provided a cylinder having a liquid supply port at one end and a liquid discharge port at the other end, and a piston shaft which reciprocates in the cylinder. A slide body disposed in the cylinder and sliding on an inner wall surface of the cylinder, the slide body being provided on the piston shaft when the piston shaft moves toward the liquid supply port. When it is moved toward the liquid discharge port by being pushed by the regulating part, it is pushed by the pushing part provided on the piston shaft to reciprocate in the cylinder to supply the liquid from the supply port and to discharge the liquid. In the liquid pump discharging from the outlet, the sliding body has a through hole penetrating the sliding body in addition to a hole penetrating the piston shaft in the movement direction of the piston shaft, and the sliding body is connected to the liquid supply port side. When moving to, open the through hole When the liquid discharge port is moved to the liquid discharge port side, the through hole is closed by the pushing portion so that the liquid flow path structure is simplified and the fluid resistance is reduced. The backflow of the liquid is minimized so that the liquid can be efficiently filled.

According to a second aspect of the present invention, in the liquid pump according to the first aspect, the sliding body has a portion having the through hole shorter than a portion penetrated by the piston shaft, so that a filling stroke is performed. The flow path of the liquid at this time is shortened to further reduce the fluid resistance, so that the backflow of the liquid can be more effectively suppressed and the liquid can be filled more efficiently.

According to a third aspect of the present invention, in the liquid pump according to the first or second aspect, the pushing portion is provided with an elastic body contact member that closes the through hole of the sliding body, thereby sucking. During the stroke, the suction port side and the discharge port side inside the cylinder are closed so that the liquid can be sucked and discharged more efficiently.

According to a fourth aspect of the present invention, in the liquid pump according to the third aspect, a reciprocating motion of the piston shaft is provided by providing a protrusion for pressing and fixing the elastic body contact member on the piston shaft. Is more efficient, and the liquid can be more efficiently supplied to the head liquid chamber.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(Invention of Claim 1) FIG. 1 is a sectional view of an essential part of an ink suction pump for explaining an embodiment of the present invention. Hereafter, the same operation as that of the prior art shown in FIG. The parts have the same reference numerals as in FIG.
Also in the ink suction pump of the present invention, as in the prior art shown in FIG. 11, a cylinder 3 having an ink inlet 1 at one end and an outlet 2 at the other end, and the inside of the cylinder 3 are provided. A reciprocating piston shaft 4 is integrally attached to the piston shaft 4, and according to the reciprocating motion of the piston shaft 4, it is pulled by the sliding body restricting portion 4a when moving in the direction of arrow A, and the pushing portion 4b when moving in the direction of arrow B. And a sliding body 5 made of an elastic body that reciprocates while being slid on the inner wall surface of the cylinder 3, and the sliding body 5 is provided in addition to the hole through which the piston shaft 4 ′ penetrates. There is a through hole 5d penetrating 5 in the axial direction.

During the filling stroke (when moving in the direction of arrow A),
The sliding body 5 is brought into contact with the sliding body regulating portion 4a, and at the same time, the contact surface between the sliding body 5 and the pushing portion 4b is opened, and the ink in the suction port side ink chamber 6 is discharged through the through hole 5d. The side ink chamber 7 is filled. As described above, in this embodiment, the flow path of the ink at the time of the filling process has a simple structure with no corners, so that the fluid resistance can be minimized to prevent the backflow of the ink and the ink can be efficiently filled. I have to.

On the other hand, during the intake stroke (when moving in the direction of arrow B)
The sliding body 5 is moved by the pushing portion 4b with the through hole 5d being sealed, and as described above, the suction port side ink chamber 6 sucks the ink from the suction port 1 and, at the same time, the discharge port side ink. The chamber 7 discharges ink from the discharge port 2. As described above, in this embodiment, the pressing portion 4b seals the through hole 5d to close the suction port side ink chamber 6 and the discharge port side ink chamber 7 so that the ink can be sucked and discharged efficiently.

(Invention of Claim 2) FIG. 2 is a sectional view of an essential part of an ink suction pump for explaining an embodiment of the invention of Claim 2. As shown in the figure, the sliding member 5 has a through hole 5d. Is made shorter by L than the portion through which the piston shaft 4 ′ penetrates. That is, in the present embodiment, the flow path through which the ink passes during the filling process (when moving in the direction of the arrow A) is shortened by the length L to further reduce the fluid resistance, and the reverse flow of the ink is more effectively performed. The ink is suppressed to allow the ink to be filled more efficiently.

FIG. 3 is an enlarged cross-sectional view of an essential part of the ink suction pump for explaining the flow of ink during the filling stroke in the invention of claim 2, and as shown in the drawing, during the filling stroke (arrow A).
(When moving in the direction), the piston shaft 4 moves toward the sliding body regulating portion 4a.
Is brought into contact with the sliding body 5 and pulled in the direction of the arrow A, and the sliding body 5 is moved while sliding on the inner wall surface of the cylinder 3 to open a gap in the contact surface between the sliding body 5 and the pushing portion 4b. The ink flow path shown by arrow C is formed by communicating with the through hole 5d of No. 5, and thus the structure of the ink flow path is simplified and the ink in the suction port side ink chamber 6 is discharged. Fill chamber 7. As described above, in this embodiment, since the through hole 5d of the sliding member 5 is shortened, the fluid resistance is further reduced, and the backflow of ink can be more effectively suppressed, and the ink can be filled more efficiently. .

FIG. 4 is an enlarged sectional view of an essential part of the ink suction pump for explaining the flow of ink during the suction stroke according to the second aspect of the present invention.
(When moving in the direction), the piston shaft 4 moves while sliding the sliding body 5 on the inner wall surface of the cylinder 3 by bringing the pushing portion 4b into close contact with the sliding body 5 to seal the through hole 5d. Then, as indicated by arrow D, the ink is sucked into the ink chamber 6 on the suction port side from the suction port 1 and discharged from the ink chamber 7 on the discharge port side through the discharge port 2. As described above, in this embodiment, since the through hole 5d is closed by the pushing portion 4b, the ink can be efficiently sucked and discharged.

FIG. 5 is a perspective view showing an example of the sliding body 5 according to the second aspect of the present invention. As shown in the drawing, the sliding body 5 has a through hole 5d.
The part 5e with the
It's just short. As a result, the ink flow path is shortened by the distance L, and as described above, the fluid resistance is further reduced, the backflow of the ink is more effectively suppressed, and the ink can be filled more efficiently. Although the illustrated embodiment has four through holes 5d, the present invention is not limited thereto. Further, the plurality of through holes 5d,
It is desirable that the pistons are arranged so as to keep the balance of the piston movement and the balance of the ink flow rate.

FIG. 6 is a perspective view of a sliding body for explaining another embodiment of the invention of claim 2, in which the sliding body restricting portion 4a connected to the piston penetrating portion 4'is shown in FIG. It is formed in a cross shape so that the space between the piston shaft penetrating portion 4'and the sliding body 5 can also be used as an ink flow path. In addition to the flow path of ink by the plurality of through holes 5d shortened by the distance L The number of passages is increased, so that the fluid resistance is further effectively reduced, the backflow of the ink is more reliably suppressed, and the ink can be filled more efficiently.

(Invention of Claim 3) FIG. 7 is a sectional view of an essential part of an ink suction pump for explaining an embodiment of the invention of Claim 3. As shown in the drawing, the pushing portion 4b is provided with a sliding member 5. Has an elastic body contact member 8 attached to the contact surface thereof, and the piston shaft penetrating portion 4 ′ is axially supported so as to penetrate the elastic body contact member 8. During the intake stroke (when moving in the direction of arrow B)
In addition, the pushing portion 4b and the sliding body 5 are more closely brought into close contact with each other by the elastic body contact member 8 and the through hole 5d is surely sealed by the pushing portion 4b, so that the inside of the cylinder 3 and the suction port 1 side are exhausted. Exit 2
The side is closed to allow the ink to be sucked and discharged more efficiently.

(Invention of Claim 4) FIG. 8 is a sectional view of an essential portion of an ink suction pump for explaining an embodiment of the invention of Claim 4, in which, as shown, the piston shaft penetrating portion 4'is The portion contacting the elastic body contact member 8 has a protrusion 4d, and the protrusion 4d
Fixes the elastic contact member 8 against the pushing portion 4b so that the piston shaft 4 can reciprocate more efficiently, thereby making the ink suction pump more stable and reliable. It is designed to demonstrate the function of.

FIG. 9 is a cross-sectional view of an essential part of an ink suction pump for explaining an embodiment in which the invention of claim 2 and the invention of claim 4 are combined.
In the sliding body 5, the portion having the through hole 5d is made shorter than the portion penetrated by the piston shaft 4 by L, and the fluid resistance is further reduced to more effectively suppress the backflow of ink, and the piston shaft penetrates during the suction stroke. The portion 4 ′ has a protrusion 4 d at a portion in contact with the elastic body contact member 8 and pushes the elastic body contact member 8.
It is fixed so as to be pressed against 4b, and the through hole 5d is blocked more effectively, so that ink can be sucked and discharged more efficiently.

FIG. 10 is a cross-sectional view of a main part of a piston shaft for explaining another embodiment of the invention of claim 4, in which the elastic contact member 8 contacts the projection 4d as shown in the drawing. A counterbore 8a is provided in a portion thereof, and the protrusion 4d is fixed by being embedded in the elastic body contact member 8 so that the protrusion 4d does not contact the sliding body 5. As a result, the reciprocating motion of the piston shaft 4 is performed more smoothly so that the ink suction pump can more effectively exert its function as the reliability maintaining mechanism.

[0025]

According to the invention of claim 1, a through hole is provided in the sliding body made of an elastic body in addition to the hole through which the piston shaft penetrates in the movement direction of the piston shaft, and the through hole serves as a liquid flow path. As a result, the flow path has no bend and has a simple structure, the fluid resistance is small, and the backflow of the liquid can be minimized to efficiently fill the liquid.

According to the second aspect of the present invention, the portion having the through hole of the sliding member is made shorter than the portion through which the piston shaft is penetrated to shorten the liquid flow path during the filling process, so that the fluid resistance is further reduced. Therefore, the backflow of the liquid can be more surely suppressed, and the liquid can be filled more efficiently.

According to the third aspect of the present invention, since the contact member made of an elastic body is provided on the surface of the portion of the piston shaft pushing portion that comes into close contact with the sliding portion during the suction stroke, the pushing portion and the sliding body are more Since the suction port side and the discharge port side are tightly and closely closed, the liquid can be sucked and discharged more efficiently.

According to the fourth aspect of the present invention, the piston shaft has a protrusion at the portion that pivotally supports the contact member provided in the push portion, and the contact member is pressed against the surface of the push portion by this protrusion. Since the piston pump reciprocates, the reciprocating motion of the piston shaft becomes smoother, and the liquid pump can more effectively exert its function as the reliability maintaining mechanism.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of an ink suction pump for explaining an embodiment of the present invention.

FIG. 2 is a conceptual sectional view of an ink suction pump for explaining an embodiment of the invention of claim 2;

FIG. 3 is a cross-sectional view of a main part of an ink suction pump for explaining the flow of ink during a filling stroke according to the second aspect of the invention.

FIG. 4 is a cross-sectional view of an essential part of an ink suction pump for explaining the flow of ink during a suction stroke according to a second aspect of the invention.

FIG. 5 is a perspective view of a sliding body for explaining the invention of claim 2;

FIG. 6 is a perspective view of a sliding body for explaining the invention of claim 2;

FIG. 7 is a cross-sectional view of an essential part of an ink suction pump for explaining an embodiment of the invention of claim 3;

FIG. 8 is a cross-sectional view of an essential part of an ink suction pump for explaining an embodiment of the invention of claim 4;

FIG. 9 is a sectional view of an essential part of an ink suction pump for explaining an embodiment in which the invention of claim 2 and the invention of claim 4 are combined.

FIG. 10 is a sectional view of a main part of a piston shaft for explaining another embodiment of the invention of claim 4;

FIG. 11 is a cross-sectional view of a main part for explaining a main part of an ink suction pump according to a conventional technique.

[Explanation of symbols]

1 ... Suction port, 2 ... Discharge port, 3 ... Cylinder, 4 ... Piston shaft, 4 '... Piston shaft penetrating portion, 4a ... Sliding body regulating portion, 4b ...
Piston shaft pushing portion, 4c ... Projection portion, 5 ... Sliding member, 5d ... Through hole, 6 ... Intake port side ink chamber, 7 ... Discharge port side ink chamber, 8
... Elastic contact member, 8a ... Counterbore part.

Claims (4)

[Claims] 1. A cylinder having a liquid supply port at one end and a liquid discharge port at the other end, a piston shaft that reciprocates in the cylinder, and a cylinder provided in the cylinder. A slide body that slides on the inner wall surface, and when the slide body moves in the direction of the liquid supply port, the slide body is pulled by a restriction portion provided on the piston shaft, and the liquid discharge port is provided. In the liquid pump that is pushed by the pushing portion provided on the piston shaft to reciprocate in the cylinder to supply the liquid from the supply port and discharge the liquid from the discharge port, Has a through hole penetrating with the sliding body in addition to a hole through which the piston shaft penetrates in the movement direction of the piston shaft, and opens the through hole when moving the sliding body toward the liquid supply port side. Move it in the A liquid pump characterized in that, when the liquid pump moves to the body discharge port side, the through hole is closed by the pushing portion to move. 2. The liquid pump according to claim 1, wherein
In the liquid pump, a portion having the through hole is shorter than a portion penetrated by the piston shaft. 3. The liquid pump according to claim 1, wherein the pushing portion has an elastic body contact member that closes the through hole of the sliding body. 4. The liquid pump according to claim 3,
A liquid pump comprising a protrusion for pressing and fixing the elastic body contact member on the piston shaft.