JP2007198242A - Tube pump and liquid injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tube pump and a liquid injection device capable of generating sufficient negative pressure without increasing the rotary torque of a motor. <P>SOLUTION: The tube pump 100 includes a tube 110 composed of an elastic body sucking liquid, an abutment part 120 arranged movably along the tube, a rotation part 130 moving the abutment part along the tube, and a motor 150 generating movement torque for moving the abutment part along the tube. The tube includes a hollow part 111 conveying liquid and a wall 112 covering the hollow part 111. The tube is crushed to make walls mutually abut on each other by the abutment of the abutment part, and the walls are restored by the separation of the abutment part. The wall includes a plurality of kinds of hardness different walls different in hardness. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tube pump for sucking liquid and the like and a liquid ejecting apparatus.

2. Description of the Related Art Conventionally, ink jet recording apparatuses have an ink jet recording head for ejecting ink onto recording paper or the like. Since this ink jet recording head discharges ink onto recording paper or the like via a nozzle, the ink thickens in the vicinity of the nozzle or bubbles are mixed in the nozzle, making it impossible to discharge the ink satisfactorily. There was a fear.
For this reason, the ink jet recording apparatus is provided with a head cleaning device in order to avoid these phenomena.

The head cleaning device has a capping unit arranged so as to cover the nozzles and a pump for making negative pressure in the capping unit, and is configured to perform cleaning by sucking ink in the vicinity of the nozzles by the pump. ing.
As the pump, a tube pump having a relatively simple structure and easy to be miniaturized is used (for example, Patent Document 1).
As shown in FIG. 7 and the like of Patent Document 1, the tube pump is configured to suck ink by moving the roller 780 in the clockwise direction, for example, while crushing the tube 75.
That is, the roller 780 moves while crushing the tube 75, but the tube 75 attempts to restore the original state from the crushed state after the roller 780 has passed. At this time, a negative pressure is generated in the tube 75 to be restored, and the ink is smoothly conveyed in the tube 75 by this negative pressure.
Thus, it is preferable that the negative pressure generated in the tube 75 is as large as possible, but for that purpose, it is desirable that the tube 75 be completely crushed.
JP 2004-34525 A (FIG. 3 etc.)

FIG. 6A is a schematic explanatory view showing a state before the conventional tube 75 is crushed, and FIG. 6B is a schematic explanatory view showing a state in which the conventional tube 75 is crushed.
As shown in FIG. 6A, when the tube 75 having the thickness t is crushed by the roller 780 in the direction of the arrow in the figure, the tube 75 is crushed to the thickness 2t as shown in FIG. 6B.
However, in this state, as shown in FIG. 6B, there is a problem that the gap S is generated, the tube 75 is not completely crushed, and the negative pressure during the subsequent restoration cannot be sufficiently generated. It was.
Therefore, conventionally, in order to prevent the gap S of FIG. 6B from being generated, it is necessary to further crush the tube 75 from the state of FIG. For example, it is necessary to further crush the tube 75 in FIG.
In this way, if the tube 75 is crushed excessively, the reaction force from the tube 75 becomes stronger, so that it is necessary to increase the rotational torque of the tube pump motor, and the efficiency of the tube pump decreases. was there.

  Therefore, an object of the present invention is to provide a tube pump and a liquid ejecting apparatus that can generate a sufficient negative pressure without increasing the rotational torque of a motor.

  According to the present invention, the subject is a tube portion made of an elastic body for sucking a liquid, an abutting portion arranged to be movable along the tube portion, and the abutting portion along the tube portion. A rotating part that moves, and a motor part that generates a moving torque for moving the contact part along the tube part, the tube part having a hollow part through which the liquid is conveyed, A wall portion covering the hollow portion, and the tube portion is crushed so that the wall portions come into contact with each other by the contact of the contact portion, and the wall portion is separated by the separation of the contact portion. This is achieved by a tube pump characterized in that the wall portion includes a plurality of types of hardness-specific wall portions having different hardnesses.

According to the above configuration, since the wall portion of the tube portion includes a plurality of types of hardness-specific wall portions having different hardnesses, the wall portions are crushed by the abutment of the abutment portion, and the portions that abut against each other For example, an elastic body with low hardness can be disposed.
Since an elastic body having low hardness is easily deformed in this way, for example, the generation of a gap (see FIG. 6) that has conventionally occurred can be suppressed without particularly increasing the rotational torque of the tube pump motor. it can.
On the other hand, an elastic body having high hardness can be arranged on the outside of the wall portion of the tube portion, for example.
Thus, an elastic body with high hardness has a large restoring force. By the way, if an elastic body having low hardness is used to prevent the generation of a gap as described above, no gap is generated, but the restoring force is inferior.
In this respect, the lack of restoring force can be compensated by the elastic body having high hardness arranged outside the tube portion.
That is, the wall portion of the tube portion is completely crushed by the contact of the contact portion, and no gap is generated. Further, the wall portion is restored by the separation of the contact portion, and a large negative pressure can be generated.
Thus, the tube pump can generate a sufficient negative pressure without increasing the rotational torque of the motor unit.

  Preferably, the plurality of different types of hardness-specific wall portions having different hardnesses are two types of elastic bodies having different hardnesses, and the hardness-specific wall portion is an inner layer wall portion that is the wall portion on the hollow portion side. The outer layer wall portion disposed outside the inner layer, wherein the hardness of the elastic body of the outer layer wall portion is greater than the hardness of the elastic body of the inner layer wall portion, and the elastic body of the outer layer wall portion is The tube pump has a hardness capable of securing a restoring force of the outer layer wall portion, and the elastic body of the inner layer wall portion has a hardness that easily crushes the inner layer wall portion.

According to the above configuration, since the elastic body of the inner layer wall portion has a hardness that easily crushes the inner layer wall portion, the contact portion is brought into contact with the tube portion without increasing the rotational torque of the motor portion. However, the tube portion can be completely crushed without generating a gap (see FIG. 6).
Moreover, according to the said structure, the elastic body of an outer layer wall part has the hardness which can ensure the restoring force of an outer layer wall part.
Accordingly, since the outer layer wall portion compensates for the lack of restoring force of the inner layer wall portion, the inner layer wall portion is not completely crushed by the contact of the abutting portion as a whole, and no gap is generated. Further, the wall portion is restored by the separation of the contact portion, and a large negative pressure can be generated.
Thus, the tube pump can generate a sufficient negative pressure without increasing the rotational torque of the motor unit.

  Preferably, the elastic body is made of silicone rubber, the hardness of the silicone rubber of the outer layer wall is 50 degrees to 70 degrees, and the hardness of the silicone rubber of the inner layer wall is 35 degrees to 40 degrees. The tube pump is characterized.

  According to the present invention, the subject is a tube portion made of an elastic body for sucking a liquid, an abutting portion arranged to be movable along the tube portion, and the abutting portion along the tube portion. A rotating part that moves, and a motor part that generates a moving torque for moving the contact part along the tube part, the tube part having a hollow part through which the liquid is conveyed, A wall portion covering the hollow portion, and the tube portion is crushed so that the wall portions come into contact with each other by the contact of the contact portion, and the wall portion is separated by the separation of the contact portion. This is achieved by a liquid ejecting apparatus having a tube pump, wherein the wall portion includes a plurality of types of hardness-specific wall portions having different hardnesses.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
The embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

  FIG. 1 is a schematic perspective view showing an ink jet recording apparatus (hereinafter referred to as “recording apparatus”) 10 according to an embodiment of a liquid ejecting apparatus having a tube pump according to an embodiment of the present invention.

(About the general configuration of the recording apparatus 10)
As shown in FIG. 1, the recording apparatus 10 includes a frame 11, and a platen 12 is disposed on the frame 11. On the platen 12, the paper P is fed by a paper feed mechanism (not shown).
Further, the recording apparatus 10 includes a carriage 13, and the carriage 13 is supported so as to be movable in the longitudinal direction of the platen 12 via a guide member 14, and is reciprocated by a carriage motor 15 via a timing belt 16. It has become.

An ink jet recording head (hereinafter referred to as “recording head”) 20 is mounted on the lower portion of the carriage 13. The recording head 20 is configured to eject, for example, ink that is a liquid with respect to the paper P.
Specifically, the recording head 20 has a nozzle that ejects ink, and is configured to eject ink droplets from the nozzle by expansion and contraction of a piezoelectric vibrator.
An ink cartridge 17 that contains ink is detachably mounted on the carriage 13, and the ink is supplied from the ink cartridge 17 to the recording head 20.
In other words, while the carriage 13 moves along the platen 12, the piezoelectric vibrator is expanded and contracted based on the print data, so that ink is ejected from the recording head 20 onto the paper P and printing is performed. ing.

In the frame 11 of FIG. 1, the paper P is arranged and has a print region T where printing is performed on the paper P. Further, the frame 11 has a home position H which is a non-printing area on one end side thereof.
The carriage 13 is configured to move between the printing region T and the home position H by moving along the platen 12.

(About composition at home position H)
As shown in FIG. 1, a head cleaning mechanism 30 is disposed at the home position H. The head cleaning mechanism 30 has a cap holder 31 and a tube pump 100. The cap holder 31 is installed on the frame 11 so as to be movable up and down by a known lifting means (not shown).

The head cleaning mechanism 30 has a cap 32. The cap 32 has a configuration in which the upper end edge of the cap 32 comes into contact with the nozzle plate or the like of the recording head 20 to seal the nozzles of the recording head 20.
By the way, as shown in FIG. 1, the recording apparatus 10 includes a blade 19. The blade 19 is in contact with the nozzle plate of the recording head 20 and performs a wiping operation by wiping off ink.

FIG. 2 is a schematic diagram showing the head cleaning mechanism 30 and the like of FIG.
As shown in FIG. 2, a sheet-like sponge 32 a is disposed at the bottom of the cap 32. The sponge 32a is configured to face the nozzles of the recording head 20 with a predetermined interval in a state where the cap 32 is in contact with the recording head 20, and absorb ink ejected from the nozzles of the recording head 20. .

Furthermore, as shown in FIG. 2, the cap 32 is formed with a discharge port 32b so as to penetrate the bottom surface thereof.
The tube pump 100 is provided in the frame 11 with the cap 32 sealing the nozzles of the recording head 20, reducing the pressure in the cap 32 to a negative pressure, and sucking ink from the nozzles of the recording head 20. The ink is discharged to the waste ink tank 33.

(Main configuration of tube pump 100)
FIG. 3 is a schematic diagram showing the main internal configuration and the like of the tube pump 100.
As shown in FIG. 3, the tube pump 100 includes a tube 110 that is a tube portion for sucking ink.
The tube 110 has such a shape that both ends of a flexible tube bent in an annular shape are pulled out in the same direction and bundled in the same plane.
FIG. 4 is a schematic diagram showing a cross-sectional configuration of the tube 110 of FIG. As shown in FIG. 4, the tube 110 has a hollow portion 111 through which ink is conveyed at the center thereof. Around the hollow portion 111, a wall portion 112 made of an elastic body is formed.
As shown in FIG. 4, the wall portion 112 includes an inner layer wall portion 112a that is the wall portion 112 on the middle portion 111 side, and an outer layer wall portion 112b that is disposed outside the inner layer wall portion 112a.
The wall portion 112 is made of, for example, silicone rubber, the hardness of the silicone rubber of the outer layer wall portion 112b is 50 degrees to 70 degrees, and the hardness of the silicone rubber of the inner layer wall portion 112a is 35 degrees to 40 degrees. It is made up.

That is, the hardness of the elastic body of the outer layer wall portion 112b is formed larger than the hardness of the elastic body of the inner layer wall portion.
Thus, the inner layer wall portion 112a and the outer layer wall portion 112b are examples of two types of hardness-specific wall portions having different hardnesses of the wall portion 112.

Incidentally, as shown in FIG. 3, the tube pump 100 includes, for example, a columnar pulley 120 that is an abutting portion that is arranged to be movable along the inner periphery of the tube 110. The pulley 120 is configured to be rotatable about the pulley central shaft 121.
Further, the tube pump 100 includes, for example, a disk-shaped rotating plate 130 that is a rotating unit that moves the pulley 120 along the inner periphery of the tube 110.
Further, as shown in FIG. 3, for example, a stepping motor 150, which is a motor unit that generates a moving torque for moving the pulley 120 along the tube 110, is connected to the rotating plate 130.
That is, when the stepping motor 150 is driven, the rotating plate 130 rotates, and the rotation of the rotating plate 130 causes the pulley 120 to move while crushing the tube 110 on the inner peripheral side of the tube 110.

FIG. 5 is a schematic explanatory view showing a state in which the tube 110 is crushed by the pulley 120. As shown in FIG. 5, when the tube 110 of the present embodiment is crushed, unlike the conventional tube 75 of FIG. 6, there is no gap S, and the tube 110 is completely crushed.
That is, in the prior art, as shown in FIG. 6, even if the tube 75 is crushed to the thickness (2t) of the wall portion, the gap S still remains, so that the gap S is further crushed by 0.6 mm. Was completely crushed.
However, in this embodiment, since the hardness of the silicone rubber of the inner layer wall portion 112a of the tube 110 is as low as 35 degrees to 40 degrees and soft, as shown in FIG. 5, the thickness (2t) of the wall section 12 of the tube 110 is obtained. 6 can be eliminated.
Thus, in the present embodiment, unlike the prior art, it is not necessary to increase the rotational (moving) torque of the stepping motor 150 to such an extent that it can be crushed more than the thickness (2t) of the wall portion.
That is, the silicone rubber of the inner layer wall portion 112a has a hardness that can be easily crushed.

Normally, when the pulley 120 crushes the tube 110 excessively, the reaction force from the wall portion 112 of the tube 110 also increases accordingly, so it is necessary to increase the rotational torque of the stepping motor 150 and the efficiency of the tube pump 100 is poor. There was a problem of becoming.
In this respect, in the present embodiment, since it is not necessary to crush extra, the efficiency of the tube pump 100 does not deteriorate.

3 and 4, the tube 110 once completely crushed by the pulley 120 returns to the original state by the restoring force of the tube 110 when the pulley 120 moves and separates. A large negative pressure is generated in the hollow portion 111 of the tube 110 to be restored, and the ink is transported by this negative pressure.
Therefore, when this restoration becomes insufficient, sufficient negative pressure is not generated, and the efficiency of the tube pump 100 is lowered.
Usually, when the hardness of the silicone rubber is lowered, the silicone rubber becomes soft and easily deformed, but its restoring force is inferior.
In this respect, in the present embodiment, as shown in FIG. 4, silicone rubber having high hardness (high restoring force) is disposed outside the inner layer wall portion 112 a having low hardness.
For this reason, the outer layer wall portion 112b is configured to compensate for the lack of restoring force of the inner layer wall portion 112a.
That is, the silicone rubber of the outer layer wall portion 112b has a hardness that can secure a restoring force.

  Thus, in the present embodiment, the tube 110 crushed by the pulley 120 is completely crushed (closed) as shown in FIG. 5 without requiring an extra rotational torque from the stepping motor 150, and thereafter When the pulley 120 is separated, the original state is restored, and sufficient negative pressure is generated in the hollow portion 111. For this reason, it can be set as the efficient tube pump 100. FIG.

  The present invention is not limited to the above-described embodiment. The present invention is not limited to an ink jet recording apparatus, but a recording head used in an image recording apparatus such as a printer, a color material ejecting head used in manufacturing a color filter such as a liquid crystal display, an organic EL display, and an FED (surface emitting). Electrode material ejection heads used for electrode formation such as displays), liquid ejection devices using liquid ejection heads that eject liquids such as bio-organic matter ejection heads used in biochip manufacturing, sample ejection devices as precision pipettes, etc. Applicable.

1 is a schematic perspective view illustrating an ink jet recording apparatus according to an embodiment of a liquid ejecting apparatus having a tube pump according to an embodiment of the present invention. It is the schematic which shows the head cleaning mechanism etc. of FIG. It is the schematic which shows the main internal structures etc. of a tube pump. It is the schematic which shows the cross-sectional structure of the tube of FIG. It is a schematic explanatory drawing which shows the state by which the tube was crushed with the pulley. (A) is a schematic explanatory drawing which shows the state before the conventional tube is crushed, (b) is a schematic explanatory drawing which shows the state where the conventional tube was crushed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 20 ... Inkjet recording head, 100 ... Tube pump, 110 ... Tube, 111 ... Hollow part, 112 ... Wall part, 112a ... Inner layer Wall part, 112b ... outer layer wall part, 120 ... pulley, 121 ... pulley central axis, 130 ... rotating plate, 150 ... stepping motor

Claims (4)

A tube portion made of an elastic body for sucking a liquid;
An abutting portion arranged to be movable along the tube portion;
A rotating part that moves the contact part along the tube part;
A motor unit for generating a moving torque for moving the abutting part along the tube part,
The tube part is
A hollow portion through which the liquid is conveyed;
A wall portion covering the hollow portion,
The tube portion is crushed so that the wall portions come into contact with each other by the contact of the contact portion, and the wall portion is restored by the separation of the contact portion,
The tube pump, wherein the wall portion includes a plurality of types of hardness-specific wall portions having different hardnesses. The plurality of types of hardness-specific wall portions having different hardnesses are two types of elastic bodies having different hardnesses,
The wall according to hardness is
An inner wall portion that is the wall portion on the hollow portion side;
An outer layer wall disposed outside the inner layer,
The hardness of the elastic body of the outer layer wall portion is larger than the hardness of the elastic body of the inner layer wall portion,
The elastic body of the outer layer wall portion has a hardness capable of securing a restoring force of the outer layer wall portion,
The tube pump according to claim 1, wherein the elastic body of the inner layer wall portion has a hardness that can easily crush the inner layer wall portion. The elastic body is made of silicone rubber,
The hardness of the silicone rubber of the outer wall portion is 50 degrees to 70 degrees,
The tube pump according to claim 2, wherein the hardness of the silicone rubber of the inner layer wall portion is 35 degrees to 40 degrees. A tube portion made of an elastic body for sucking a liquid;
An abutting portion arranged to be movable along the tube portion;
A rotating part that moves the contact part along the tube part;
A motor unit for generating a moving torque for moving the abutting part along the tube part,
The tube part is
A hollow portion through which the liquid is conveyed;
A wall portion covering the hollow portion,
The tube portion is crushed so that the wall portions come into contact with each other by the contact of the contact portion, and the wall portion is restored by the separation of the contact portion,
The liquid ejecting apparatus having a tube pump, wherein the wall portion includes a plurality of types of hardness-specific wall portions having different hardnesses.

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