JPH07259727A - Fluid suction pump and ink jet recording device employing the fluid suction pump - Google Patents

Abstract

PURPOSE:To realize the ink jet recording device, that is, the ink jet recording device employing both a suction pump sucking fluid, and an ink suction pump employing the suction pump, which is realized as a fluid suction pump capable of stably sucking fluid with its device made small in size and simple in structure, and enable accurate treatment by utilizing the pump. CONSTITUTION:A suction port 3 is provided around a cylinder 1, and an harge port 4 is provided around the end section of the cylinder 1. When a piston 2 is moved to the direction of discharge, the suction port 3 is kept shielded by the piston 2, and when the piston 2 is moved to the direction of suction, the suction port 3 is released in the vicinity of a limit point in the direction of suction. Besides, a spherical member 7 is pushed up by the compression force of a spring 8 at the discharge port, and it is pushed down by the tip end of the piston 2. The tip end of the piston 2 is fabricated into a tapered shape, and at least one of either of the spherical, member 7 or a section receiving the spherical member 7 is formed out of an elastic member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid suction pump for sucking a fluid, and more particularly to an ink suction pump used in an ink jet recording apparatus for performing processing such as printing on a medium by ejecting ink from a nozzle. The ink jet head of an ink jet recording apparatus causes ejection failure due to thickened ink in the vicinity of a nozzle, or the pressure of ejecting an ink droplet due to minute air bubbles penetrating from the nozzle is absorbed by the air bubble, causing incomplete ink droplet ejection. Therefore, the printing result may be significantly impaired.

In order to solve the above problems, an ink jet recording apparatus in which a suction pump for sucking thickened ink or bubbles adhering to a nozzle is installed is widely used.

[0003]

2. Description of the Related Art As a suction pump for sucking ink from an ink jet head, there is known a piston pump for sucking ink from a suction port due to a pressure change when a piston moves in a cylinder. FIG. 5 is a diagram showing a conventional suction pump. Reference numeral 1 is a cylinder, which forms the appearance of a suction pump. 2 is a piston, and 1 is a cylinder
Move left and right inside the. Reference numeral 1A denotes a first pressure chamber, which refers to the inside of the cylinder on the left side of the right end of the piston 2. 1
B is a second pressure chamber, and refers to the inside of the cylinder on the right side of the right end of the piston 2. An inlet 3 is connected to an inkjet head (not shown). A discharge port 4 discharges the ink to the outside of the cylinder 1. 5 is a compression spring, which is connected to the right end of the piston 2,
The position of the piston 2 is fixed by the extension force. 6A
Is a through hole, which is provided at the right end of the piston 2, and the ink in the first pressure chamber 1A flows into the second pressure chamber 1B through the through hole 6A. Reference numeral 6B is a film valve, which is formed of a film-like elastic member, one end of which is fixed to the right front end of the piston 2 and the other end of which operates to open and close the through hole 6A.

When the piston 2 is pushed to the right, the first
Negative pressure is generated in the pressure chamber 1A, and the ink in the inkjet head flows from the suction port 3 into the first pressure chamber 1A. The piston 2 pushed to the right side is pushed back to the left side by the extension force of the compression spring 5. When the piston 2 moves to the left, the negative pressure in the first pressure chamber 1A is gradually released, and eventually the film valve 6B is opened against the elastic force of the film valve 6B and the pressure of the second pressure chamber 1B. The ink in the first pressure chamber 1A flows into the second pressure chamber 1B.

The ink flowing into the second pressure chamber 1B is discharged from the discharge port 4 to the outside of the cylinder when the piston 2 is pushed rightward again. By the above-mentioned operation, the ink in the inkjet head is sucked.

[0006]

In the conventional suction pump, since the suction operation and the discharge operation are performed in separate pressure chambers, two pressure chambers are required, and it is difficult to reduce the size. There was a problem. Further, since the ink sucked due to the pressure change is discharged only due to the pressure change, it is difficult to dry the ink inside the suction pump to remove the ink stuck around the discharge port only by the pressure, and the discharge port is dried. There is a problem in that the ink is blocked and the stable ink suction cannot be performed as a result.

Moreover, if the dust such as the paper dust attached to the nozzle is sucked together with the ink and cannot be removed, the airtightness of the suction pump is impaired. It was An object of the present invention is to solve the above problems, to realize an ink suction pump that is capable of stable ink suction with a small and simple structure, and by mounting the pump on an inkjet recording apparatus,
It is to realize an inkjet recording apparatus that can perform accurate processing.

[0008]

FIG. 1 is a principle diagram showing the principle configuration of the present invention. Parts corresponding to those in FIG. 5 are assigned the same reference numerals and explanations thereof are omitted. The above figures are claims 1 to 4.
Represents the fluid suction time of the fluid suction pump described in
The piston 2 has moved to the limit point in the suction direction (left direction) and does not move any further in the suction direction.

The middle figure shows the time when the fluid suction pump according to any one of claims 1 to 4 discharges the fluid, and the piston 2 has moved to the limit point in the discharge direction (right direction), and further discharge direction Does not move to. The figure below shows a fluid suction pump according to claims 5 and 6. Reference numeral 7 denotes a spherical member, which is installed at the discharge port 4. Reference numeral 8 is a spring, which pushes up the spherical member 7 by the extension force. 9
Is a projecting part, projecting from the end of the cylinder 1,
A space for guiding the movement of the piston 2 is formed. Reference numeral 10 is a guide rod, which is fixed to the tip of the piston and moves on the protrusion (9). Reference numeral 11 denotes a groove, which is provided in the longitudinal direction of the guide rod (10).

In the upper and middle figures, the suction port 3 is provided in the peripheral portion of the cylinder 1, and when the piston 2 moves in the fluid discharge direction (right direction), the piston 2
The piston 2 is installed at a position where the piston 2 is released from the piston 2 when the piston 2 moves in the fluid suction direction (leftward direction) and reaches the vicinity of the suction direction limit point. The discharge port 4 is provided around the end portion of the cylinder 1, and when the piston 2 moves to the limit point in the direction (right direction) for discharging the fluid, the tip end portion of the piston 2 reaches and the spherical member 7 is reached. It is provided at the position where it hits.

The tip of the piston 2 is tapered, and at least one of the spherical member 7 and the portion for receiving the spherical member is formed of an elastic member. Further, in the lower drawing, the discharge port 4 is installed at a position where the tip end of the guide rod 10 reaches and hits the spherical member 7 when the piston 2 moves to the limit point in the fluid discharge direction of the cylinder 1. The guide rod 10 is processed into a tapered shape.

[0012]

According to the first aspect of the present invention, the suction port 3 is opened when the piston 2 moves in the suction direction (left direction) and near the suction direction limit point. At this time, an explosive suction force acts due to the negative pressure that has been generated by the movement of the piston 2 in the suction direction until then, and the fluid is sucked.

Further, the operation shifts from the suction operation to the discharge operation,
When the piston 2 starts moving in the discharge direction, the suction port 3 provided near the suction direction movement limit point moves to the piston 2
Will be shielded soon. Even when the piston 2 reaches the discharge direction movement limit point, the suction port remains shielded, and the fluid cannot flow out from the suction port 3 during the discharging operation.
Further, the suction operation and the discharge operation are performed in the same space (pressure chamber) with respect to the piston 2, and it is not necessary to separate the pressure chambers for suction and discharge, so that the pump can be downsized.

As a function of the second aspect, the spherical member 7 and the spring 8 are installed in the discharge port 4, and the spherical member 7 pushed up by the extension force of the spring 8 closes the discharge port 4.
This makes it possible to obtain a suction pump having high airtightness with a simple structure. When discharging the fluid, the piston 2 moves in the discharging direction (to the right), so that the pressure in the cylinder 1 increases, and the spherical member 7 resists the extension force of the spring 8.
Is pushed down, the discharge port 4 is opened, and the fluid is discharged.

Further, when the piston 2 moves to the limit point in the discharge direction, the discharge port 4 is provided at the position where the tip of the piston 2 reaches, so that the tip of the piston 2 forces the spherical member 7. Push down. As a result, when the fluid is discharged and the fluid is fixed around the discharge port 4 and the spherical member 7 cannot be sufficiently pushed down only by increasing the pressure, the spherical member 7 can be pushed by the tip portion of the piston 2.
Is forcibly pushed down for stable discharge of fluid.

As a function of the third aspect, since the tip portion of the piston 2 is tapered, the spherical member 7 can be reliably rotated. Further, it is possible to prevent the clogging of the discharge and the deterioration of the airtightness by scraping off the fluid fixed around the discharge port 4 and the spherical member 7 and purging dust such as paper powder which deteriorates the airtightness to the discharge port 4. it can. As an operation of claim 4, since at least one of the spherical member 7 and the portion for receiving the spherical member 7 is formed of an elastic member, the spherical member 7 can seal the discharge port 4 without a gap. The airtightness of the suction pump during suction can be improved.

As a function of the fifth aspect, the guide rod 10 closely moves inside the protrusion 9 to stabilize the movement of the piston 2. The operation of claim 6 is as follows.
The fluid sucked into the cylinder 1 flows into the inside of the protrusion 9 through the groove 11 provided in the guide rod 10. Then, when the piston 2 moves to the limit point in the fluid discharge direction of the cylinder 1, the tip end portion of the guide rod 10 moves to the discharge port 4
The spherical member 7 provided on the base is pushed down.

By installing the discharge port inside the protrusion 9, the intake volume of the fluid becomes the sum of the inside of the cylinder 1 and the inside of the protrusion 9, and as a result, the volume of the intake fluid can be increased. As a function of the seventh aspect, since the tip end of the guide rod 10 is tapered, the spherical member 7 can be reliably rotated. Further, the fluid adhering to the vicinity of the discharge port 4 and the spherical member 7 is scraped off, and dust such as paper powder that deteriorates airtightness is driven to the discharge port 4,
It is possible to prevent discharge clogging and airtightness deterioration.

According to an eighth aspect of the invention, by using the fluid suction pump according to the first aspect as an ink suction pump of an ink jet recording apparatus, an ink suction pump capable of stable ink suction with a small and simple structure. Can be realized.

[0020]

EXAMPLE FIG. 2 is a perspective view of an ink jet recording apparatus. A main paper feed shaft 10 feeds the medium in the sub-scanning direction indicated by A. A paper feed motor 11 drives the main paper feed shaft (platen) 10 to rotate. Reference numeral 12 denotes an inkjet head integrally provided with a print head 12a at the lower end of an ink tank 12b, which is installed so as to face the paper 19 and to face a nozzle protection mechanism described later when not printing.

Reference numeral 13 denotes a carriage on which the ink jet head 12 is detachably mounted. 14 is a stay shaft, on which the carriage 13 is slidably attached. A space motor 15 moves the carriage 13 via a drive belt 16. Reference numeral 17 denotes a nozzle protection mechanism, which is installed at a position where the inkjet head 12 returns when printing is not performed (referred to as a home position), and incorporates a suction pump which is an embodiment of the present invention. Reference numeral 18 denotes a cap provided with a suction port that is vertically movable by a mechanism (not shown), and the end of the internal suction port is connected to the suction port of the suction pump via a tube or the like. The cap 18 covers the print head 12a of the inkjet head 12 by moving upward to prevent the ink from drying when printing is not performed, and when printing is not performed for a predetermined time, or the inside of the nozzle of the print head 12a is blocked. When air bubbles enter and ink cannot be ejected, the suction pump sucks the ink in the ink tank 12b from the nozzle of the print head 12a through the cap 18 to restore the printable state.

The nozzle protection mechanism 17 includes a nozzle portion 12a.
Although a wiper for cleaning is also installed, illustration and detailed description are omitted. FIG. 3 is a diagram showing a suction pump of an ink jet recording apparatus which is an embodiment of the present invention.
The parts corresponding to those in FIG. 1 are designated by the same reference numerals and the description thereof is omitted. The piston 2 is formed of a piston flange 2a and a piston rod 2b, the piston flange 2a forms an umbrella portion of the piston 2, and the piston rod 2b is fitted into the piston flange 2b and moves inside the cylinder 1 together with the piston flange 2b. . 20 is a cam,
The piston 2 is moved by the rotation. Reference numeral 21 denotes a pin, which is fitted in the piston rod 2b and regulates the moving range of the piston 2.

In the upper diagram, the piston flange 2a reaches the suction direction limit point B, and in the lower diagram, the piston flange 2a.
Has reached the discharge direction limit point B. Piston flange 2
The tip of a does not move to the left of the suction direction limit point B or to the right of the discharge direction limit point A due to the action of the cam 20 and the pin 21. The drive source of the cam 20 is the paper feed motor 11 or the space motor 1.
5 is used, the description of the method of connecting the motor and the cam 20 is omitted.

Within the range in which the piston flange 2a moves within the cylinder 1, the inside of the cylinder 1 has an inner diameter D1 within which the piston flange 2a can move in close contact, and within the range in which the tip of the piston rod 2b moves. In the above, the inside of the cylinder 1 has an inner diameter D2 with which the piston rod 2b can move in close contact. Therefore, the tips of the piston flange 2a and the piston rod 2b are always in close contact with the cylinder 1, so that the piston 2 can move stably.

The tip of the piston rod 2b is always in close contact with the cylinder 1, but a groove is provided in the longitudinal direction of the piston rod 2b so that the sucked ink can be sent to the discharge port 4. FIG. 4 shows a sectional view of the piston rod 2b. Further, a notch 3a is formed at the base of the suction port 3 to stabilize the flow of the ink to be sucked, and immediately after the suction operation is switched to the discharge operation.
Ink is prevented from flowing out from the suction port 3.

The distance X from the discharge direction limit point A to the suction direction limit point B is slightly larger than the distance Y from the discharge direction limit point A to the point C where the cut 3a at the base of the suction port 3 starts. Therefore, the suction port 3 is not opened until the tip of the piston flange 2a reaches the vicinity of the suction direction limit point B. The width S of the piston flange 2a is larger than the distance T from the discharge direction limit point A to the installation point E of the suction port 3. Therefore, the piston flange 2a is at the discharge direction limit point A.
Even when the pressure reaches, the suction port 3 is shielded by the piston flange 2a.

When ink is sucked by the suction pump, the piston flange 2a moves in the suction direction (left direction) by the rotation of the cam 20, and the spherical member 7 that was pushed down at the time of discharge is pushed up by the extension force of the spring 8. , The ink discharge port 4 is closed. The spherical member 7 is an elastic member, and the portion that receives the spherical member 7 is tapered. Therefore,
The spherical member 7 pushed up by the spring 8 is
To make a tight seal.

When the piston flange 2a further moves in the suction direction, the inside of the cylinder 1 becomes a negative pressure and approaches the point C where the cut 3a of the suction port 3 starts, and the suction force due to the negative pressure accumulated up to that point is generated. Piston flange 2a
The print head 1
The thickened ink adhering to 2a and the bubbles inside the print head 12a are explosively sucked into the cylinder 1.

The piston flange 2a is at the suction direction limit point B.
When the pin reaches the crest of the cam 20, the pin 21 holds the position of the piston flange 2a until the desired amount of ink is sucked. When the suction of the desired amount of ink is completed, the cam 20 rotates in the opposite direction to the suction and the piston flange 2a begins to move in the discharge direction (right direction), and the suction port 3 is soon sealed by the piston flange 2a. .

When the piston flange 2a further moves in the discharge direction, the inside of the cylinder 1 becomes positive pressure and the spring 8
The spherical member 7 is pushed down against the extension force of the
Opens and ink is discharged. When the piston flange 2a reaches the discharge direction limit point A, the tip end portion of the piston flange 2a comes into contact with the spherical member 7 to completely push down the spherical member 7 already pushed down by the pressure, so that the ink in the cylinder 1 is removed. Eject completely.

At this time, the tip end portion of the piston rod 2b formed into a taper shape surely rotates the spherical member to drive the dust such as paper dust caught in the spherical member 7 to the discharge port 4 and to discharge it. The ink adhering to the vicinity of the outlet 4 and the spherical member 7 is scraped off. The ink thus discharged is
It is discarded in an absorbent material such as felt or sponge (not shown).

[0032]

As described above, according to the present invention,
The suction port 3 is always shielded by the piston 2 when discharging the fluid, and is installed at a position where the piston 2 is opened when the piston 2 moves to the vicinity of the limit point in the suction direction when sucking the fluid. Since the discharging operation is performed in the same space (pressure chamber) in the cylinder 1, 2
It is not necessary to create two pressure chambers, and the fluid suction pump can be miniaturized.

Further, even if the piston 2 moves in the suction direction, the suction port 3 is not opened unless it reaches the vicinity of the suction direction limit point, so that the suction force due to the negative pressure can explosively act. The suction capacity of the fluid suction pump can be increased. Further, by installing the spherical member 7 and the compression spring 8 in the discharge port 4 of the fluid suction pump, the spherical member 7 pushed up by the extension force of the spring 8 closes the discharge port 4, so that the structure is simple. A fluid suction pump with high airtightness can be obtained.

Further, when the piston 2 moves to the limit point in the discharge direction, the discharge port 4 is provided at the position where the tip of the piston 2 reaches, so that the spherical member 7 can be pushed down only by the pressure change. Even if it is not possible, the tip of the piston 2 forcibly pushes down the spherical member 7, so that the fluid can be reliably discharged. Further, the tip of the piston 2 is formed into a tapered shape, so that the discharge port 4
Shaving off the fluid adhering to the periphery and the spherical member 7,
It is possible to prevent discharge clogging of the discharge port 4.

Furthermore, by reliably rotating the spherical member 7, dust such as paper dust caught in the spherical member 7 can be driven to the discharge port 4 and the airtightness of the fluid suction pump can be maintained. Further, since at least one of the spherical member 7 and the portion that receives the spherical member 7 is formed of an elastic member, it is possible to improve airtightness during suction of the fluid suction pump.

Further, since the guide rod 10 closely moves inside the projecting portion 9, the movement of the piston 2 during the suction operation and the discharge operation can be stabilized. Further, by providing the discharge port inside the protrusion 9, the suction volume of the fluid becomes the sum of the inside of the cylinder 1 and the inside of the protrusion 9, and as a result, the volume of the suction fluid can be increased.

Further, since the tip of the guide rod 10 is tapered, the fluid stuck around the discharge port 4 and the spherical member 7 is scraped off as in the case where the piston is tapered. The clogging of the discharge port 4 can be prevented, the spherical member 7 can be reliably rotated, and dust such as paper dust caught in the spherical member 7 can be driven to the discharge port 4 to ensure the airtightness of the fluid suction pump. Can be maintained.

As described above, it is possible to realize a fluid suction pump capable of performing stable fluid suction with a simple structure, and by mounting the fluid suction pump as an ink suction pump in an ink jet recording apparatus, accurate processing can be performed. An inkjet recording device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention. The upper diagram represents the time of fluid suction of the fluid suction pump according to claims 1 to 4, and the lower diagram represents the time of fluid discharge of the fluid suction pump according to claims 1 to 4. Further, the following figure shows the fluid suction pump according to claims 5 to 7.

FIG. 2 is a perspective view of an inkjet recording apparatus.

FIG. 3 is a suction pump mounted on the inkjet recording apparatus according to the embodiment of the present invention. The upper figure shows the operation when ink is sucked, and the lower figure shows the operation when ink is discharged.

FIG. 4 is a view showing a sectional view of a piston rod 2b.

FIG. 5 is a diagram showing a conventional suction pump.

[Explanation of symbols]

 1 ... Cylinder 2 ... Piston 3 ... Suction port 4 ... Discharge port 7 ... Spherical member 8 ... Spring 9 ... Projection part 10 ... Guide rod 11 ... Groove

Claims (8)

[Claims] 1. A cylinder (1) forming a pressure chamber, a piston (2) moving in the cylinder, and a suction port (3) for introducing a fluid into the cylinder (1).
And a discharge port (4) for discharging the fluid inside the cylinder (1) to the outside, and the suction of the fluid is performed by the pressure change caused by the movement of the piston (2) in the cylinder (1). A fluid suction pump for performing, wherein the discharge port (4) is provided around the end of the cylinder (1).
Further, the suction port (3) is formed around the cylinder (1), and when the piston (2) moves in the discharging direction on the discharge port (4) side, the suction port is moved by the piston (2). (3) continues to be shielded, and when the piston (2) moves in the suction direction on the suction port (3) side, the suction port (3) is close to the piston (2) near the movement limit point. The fluid suction pump is characterized by being released from the. 2. The ink discharge port (4) has a spherical member (7) for closing the discharge port (4) and a spring (8) for pressing the spherical member (7) with an extension force. Provided at a position reached by the tip of the piston (2) when the piston (2) moves to a limit point in the fluid discharge direction of the cylinder (1),
Fluid suction pump according to claim 1, characterized in that the spherical member (7) is pushed down by the piston (2). 3. The fluid suction pump according to claim 2, wherein a tip of the piston (2) is processed into a tapered shape. 4. The fluid suction according to claim 2 or 3, wherein at least one of the spherical member (7) and a portion for receiving the spherical member (7) is formed of an elastic member. pump. 5. A protrusion (9) which projects from the end of the cylinder (1) and forms a space for guiding the movement of the piston (2), and a protrusion (9) connected to the tip of the piston (2), The ink suction pump according to any one of claims 1 to 4, further comprising: a guide rod (10) that closely moves in the protrusion (9). 6. The discharge port (4) has a spherical member (7) at the tip of the guide rod (10) when the piston (2) moves to a limit point in the fluid discharge direction of the cylinder (1). 6. The fluid suction pump according to claim 5, wherein the guide rod (10) is provided with a groove (11) provided in a longitudinal direction of the guide rod (10). 7. The fluid suction pump according to claim 6, wherein a tip of the guide rod (10) is tapered. 8. An ink jet recording apparatus having a print head for ejecting ink from a nozzle to perform printing, and an ink suction pump for discharging ink from the nozzle through a cap, wherein the ink suction pump is a cylinder forming a pressure chamber. (1), a piston (2) moving in the cylinder, and a suction port (3) for introducing a fluid into the cylinder (1).
And a discharge port (4) for discharging the fluid inside the cylinder (1) to the outside, and the suction of the fluid is performed by the pressure change caused by the movement of the piston (2) in the cylinder (1). An ink suction pump for performing, wherein the discharge port (4) is provided around the end of the cylinder (1).
Further, the suction port (3) is formed around the cylinder (1), and when the piston (2) moves in the discharging direction on the discharge port (4) side, the suction port is moved by the piston (2). (3) continues to be shielded, and when the piston (2) moves in the suction direction on the suction port (3) side, the suction port (3) is close to the piston (2) near the movement limit point. Inkjet recording device characterized by being released from.