JPH06198902A - Ink jet recording apparatus - Google Patents

Abstract

(57) [Summary] [Object] To provide a tube pump for an inkjet recording apparatus, which has a simple structure, is highly durable, and is reliable. [Structure] A slide guide plate 40 rotated by a pump drive shaft 30 is coaxial with the shaft 30 between α and β, and β to γ.
Inside, there is a guide hole 41 facing the direction of the axis 30. The shaft 21 of the pressure roller 20 is inserted into the guide hole 41. Therefore, when the tube pump is not used (Fig. (B)), the pump drive shaft 3 when the pump is operating (Fig. (C))
With respect to the rotation direction A of 0, the pump drive shaft 30 is in the reverse direction B.
When the tube 2 is rotated, the rotating shaft 21 of the pressure roller 20 is moved in the axial direction of the pump drive shaft 30 by the elastic force of the tube 2 (the state shown in FIG.
Release the pressed state of.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus which is disposed in an ink supply system and supplies ink under pressure to an ink jet head. The present invention relates to a tube pump for filling air, discharging air bubbles in an inkjet head, or removing clogging of nozzles of an inkjet head.

[0002]

2. Description of the Related Art In on-demand ink jet recording, print quality is deteriorated due to inclusion of air bubbles in an ink jet head or clogging of nozzles, or
Printing may become impossible, and eliminating this is one of the major problems.

As one of the means for solving the above problems, conventionally, a pump is provided in an ink supply system for supplying ink to an ink jet head, and when the ink is filled in the ink jet head, the ink is added by the pump. The pressure was supplied to fill the inside of the inkjet head.

FIG. 5 is a diagram for explaining an example of a conventional technique for filling an ink jet head with ink. In the figure, 1 is an ink tank, 2 is an ink supply tube, 3 is a pump, and 4 is an ink jet head. 5 is a cap, 6
5A is a waste ink tank. In the example of FIG. 5A, as described above, the pump 3 is provided in the ink supply system passage 2 for supplying the ink to the inkjet head 4, and the ink is pressurized by the pump 3. The ink is supplied to the inkjet head 4, the ink is filled in the inkjet head 4, the bubbles in the inkjet head 4 are discharged, and further, the clogging of the nozzle of the inkjet head 4 is removed. At this time, the ink jet head 4 is covered with a cap 5 so that the ink flowing out of the ink jet head 4 is discharged to the waste ink tank 6 through the cap 5, thereby preventing contamination due to ink outflow. . During printing, the pump 3 does not operate, and the ink tank 1 and the inkjet head 4 communicate with each other without being blocked by the pump 3.

In the example of FIG. 5B, the pump 3 is capped with a cap 5
The ink inside the inkjet head 4 is sucked by the pump 3 so that the ink is filled in the inkjet head 4 and the air bubbles inside the inkjet head 4 are discharged or the nozzles of the nozzle It is designed to remove clogging. In this case, as a matter of course, the cap 5 is removed from the inkjet head 4 during printing, and the pump 3 does not act on the supply of ink to the inkjet head 4.

FIG. 6 is a view for explaining an example in which a tube pump is used as the pump 3. In this case, the tube pump 3 divides the inner peripheral surface of the pump case 10 into four parts. Two elastic tubes 2 ₁ , 2 ₂ , 2 ₃ ,
2 ₄ are accommodated, and eight pressure rollers 20 are installed (a position where the circumference is divided into eight). During the pump operation of the tube pump 3, when the pump drive shaft 30 is rotated in the direction A, the pressure roller 20 is guided by a guide plate (not shown) that rotates together with the pump drive shaft 30, so that the pressure roller 20 and the side surface of the pump roller 20. by the inner peripheral surface of the case 10, the elastic tube 2 ₁ -
2 ₄ is deformed under pressure and rotated while crushing.
At this time, the pressure on the I side of the elastic tube decreases to a negative pressure, and the pressure on the O side increases to a positive pressure state.

Thus, as shown in FIG. 5A, when the pressurized ink is supplied to the ink jet head side by the pump operation, the ink jet head side is O and the ink tank side is I. When the system is connected and as shown in FIG. 5B, the ink on the ink ejecting head side is sucked with a negative pressure by the pump operation, the ink ejecting head side is I and the waste ink tank side is O. Connect the supply system. The elastic tubes need not necessarily be equally divided and may be designed according to the required function. In particular, when a negative pressure is generated, the division ratio and the arrangement of the pressure roller are important.

[0008]

As described above, the tube pump provides the optimum ink supply system for the ink jet recording apparatus, but has the following drawbacks structurally. The tube 2 in the tube pump 3 is constantly pressed and squashed between the outer circumference of the pressure roller 20 and the inner wall of the pump case 10. If left in this state for a long period of time, the elastic restoring force of the tube 2 will weaken, and not only will not exhibit sufficient performance at the time of the next pump drive, but if it is left at a high temperature, it will not be restored at all, or cracks will occur. If
The tube may stick. In other words, the tube pump can achieve its purpose only by operating it for a single time before starting printing or when clearing the clogging, so it is difficult to cause deterioration of the tube due to long drive time of the pump, but it is always crushed during the stop. The above-described creep deterioration occurs due to the elastic deformation caused by the presence of the creep.

As a measure for solving the above problems,
For example, Japanese Patent Application Laid-Open No. 57-123066 proposes to release the pressing of the tube when the tube pump is not in use. As a means therefor, a method of moving the pump case 10 or a moving of the pressure roller is used. However, both require a separate drive source and drive mechanism for moving them, which not only complicates the structure but also increases the space for improving the structure, and further The cost will increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tube pump for an ink jet recording apparatus, which has a simple structure and is highly durable and reliable. It was made as.

[0011]

In order to solve the above problems, the present invention provides (1) an ink jet head, an ink supply system for supplying ink to the ink jet head, and a path of the ink supply system. And a tube pump for filling the ink ejecting head with ink, wherein the tube pump has a plurality of elastic tubes arranged so as to divide the inner peripheral surface of the pump case, and a pump drive shaft, A pressure roller having a number of elastic tubes equal to or more than the above and arranged around the pump drive shaft, and a guide plate that guides the rotation shaft of the pressure roller and moves integrally with the pump drive shaft. And a pump case that pressurizes and deforms the elastic tube in cooperation with the outer peripheral surface of the pressure roller, and drives the pump drive shaft to move the pressure roller to the tube. In an ink jet head recording apparatus having a tube pump that is rotationally moved so as to press to perform a pump operation, when the tube pump is not used, the pump drive shaft is reverse to the rotation direction of the pump drive shaft during the pump operation. The rotating shaft of the pressure roller is rotated by the elastic force of the tube to move in the axial direction of the pump drive shaft to release the pressed state of the tube. In (1),
(2) The guide plate has a guide having a region having a degree of freedom in which the rotary shaft of the pressure roller can move on the same circumference as that for pressing the tube.
(3) The guide plate is composed of two members that give the guide shaft different degrees of freedom in the rotation axis of the pressure roller, or (4) ink supply that connects the pump and the ink jet head. The system has a valve capable of opening and closing the ink supply system, and after the valve is closed, the pump drive shaft is reversely rotated to release the pressed state of the tube. And (5) an ink ejecting head, an ink supply system for supplying ink to the ink ejecting head, and a tube pump arranged in the path of the ink supplying system for filling the ink ejecting head with ink. The tube pump has a plurality (N) of elastic tubes arranged so as to equally divide the inner peripheral surface of the pump case, a pump drive shaft, and a circumference of the pump drive shaft as a center. Arranged to divide (N + 1)
Guide the pressure roller and the rotary shaft of the pressure roller,
And a guide plate that moves integrally with the pump drive shaft,
The pump case, which cooperates with the outer peripheral surface of the pressure roller to deform the elastic tube under pressure, is driven to rotate by the drive shaft of the pump to move the pressure roller against the tube. Or (6) an ink ejecting head, an ink supply system for supplying ink to the ink ejecting head, and an ink supply system disposed in a path of the ink supplying system to supply the ink to the ink ejecting head. A tube pump for filling, wherein the tube pump comprises a plurality of elastic tubes arranged so as to divide the inner peripheral surface of the pump case, a pump drive shaft, and the number of elastic tubes less than or equal to the number of the elastic tubes. A pressure roller arranged on the circumference around the drive shaft, and a guide plate for guiding the rotation shaft of the pressure roller and moving integrally with the pump drive shaft. , The pump case that cooperates with the outer peripheral surface of the pressure roller to deform the elastic tube by pressure, and is rotated by pressing the pump drive shaft to press the pressure roller against the tube. When the pump operation is stopped, the pressure roller is moved to a position which is the tube introduction part of the tube pump and is deviated from the pressure contact position of the tube to release the pressure on the tube. It is characterized by doing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining one embodiment of the present invention, and FIG. 1A is a partial view of a guide plate 40 having a function of releasing the pressed state of an elastic tube. 40
Is provided with an elongated hole-shaped guide hole 41 for rotatably supporting the rotating shaft of the pressure roller. Since the guide holes 41 correspond to the pressure rollers 20 on a one-to-one basis, the number of pressure rollers is required, but only one is shown here for the sake of simplicity. is there.

The guide hole 41 is shown in FIGS. 1 (b) and 1 (c).
As shown in FIG. 4, since the rotary shaft 21 of the pressure roller 20 is inserted into the guide 41, the rotary shaft 21 has a width equal to or larger than the shaft diameter of the rotary shaft 21. The guide holes 41 are movably supported.

FIG. 1B shows the state when the pump is not used, and FIG.
Is a diagram showing a state when the pump is used. In the state of FIG. 1 (b), the pressure roller 20 does not press the tube 2, and in the state of FIG. 1 (c), the pressure is applied. The roller 20 presses the tube 2. The pressure roller 20 cooperates with the pump case 10 to pressurize and deform the elastic tube 2 and crush the elastic tube 2 to close the inner diameter portion. When positioned, the groove center of the guide hole 41 is a groove on the same circumference of R between α and β (having a degree of freedom on the same circumference where the pressure roller presses the tube). Between β and γ, the groove center of the guide hole 41 is smoothly formed in the direction of the pump drive shaft 30 from the position R at β, and the pressure roller shaft 2
When 1 is in the position of γ, the elastic tube 2 is not pressed by the pressure roller 20 and the pump case 10.

During pump operation, as shown in FIG. 1 (c), the pump drive shaft 30 rotates in the direction A, and the pressure roller 20 is guided by the elastic force of the elastic tube itself.
1 slides in the D direction to reach the β point, and the pump operation is performed there (actually, since a sufficient margin is expected at the β point, the pump operation is started between β and γ). ), Then slide to move to point α. Due to the movement between α and β, even if the load of the elastic tube 2 changes or the elastic force applied to the pressure roller 20 changes, the pressure roller 20 moves to between β and γ to close the tube. It is possible to prevent a state in which the state cannot be obtained. That is, due to the above-mentioned fluctuation, the pressure roller 2
Even if 0 suddenly moves from the α position to the β position, it can immediately return to the α position if the pump drive shaft continues to rotate in the A direction. The movement can absorb the above fluctuation.

After the pressure roller 20 moves to α in the guide hole as described above, the tube is crushed at the point α and rotated in the direction A together with the pump shaft until the rotation of the pump drive shaft is completed. Continue pumping.

When the pump operation is completed, the tube is released from the pressure so that the tube is not used.
As shown in (b), this is performed by rotating the pump drive shaft 30 in the B direction in the reverse direction. At this time, the pressure roller 2
0 slides in the guide hole 41 in the C direction by the elastic force of the elastic tube itself, and reaches the point γ. At the point γ, the elastic tube is slightly crushed, in other words, the pressure roller and the elastic tube are in contact with each other. Therefore, only a very small amount of deformation is applied, so that the tube itself is not damaged such as deterioration. When the pump is operated again, a force for sliding the pressure roller 20 in the direction D of FIG. 1C is applied.

The tube pump according to the present invention operates as described above to discharge air bubbles in the ink jet head or remove clogging of the nozzle.
If the operation is performed as described above, the ink may flow backward in the supply system during the reverse rotation operation of the pump drive shaft. In order to prevent this, it is advisable to dispose a valve mechanism in the ink supply system and perform the reverse rotation operation of the pump drive shaft in conjunction with the valve operation.

Specifically, for example, in the case of the system shown in FIG. 5A, in the path between the ink jet head 4 and the pump 3, in the case of the system shown in FIG. 5B, A valve action is provided in the path between the cap 5 and the pump 3. Figure 5 (a)
In the case of, the valve is normally open, but in order to release the pressing of the tube, when rotating the pump drive shaft in the reverse direction,
Before that, close the valve, and after releasing the pressure, open the valve. The same applies to the case of FIG. 5B, but in this case, an opening valve is provided in the cap portion, or
The pressure may be released by rotating the pump drive shaft in the reverse direction after separating the supply system on the pump side from the ink jet head substantially by separating the cap. In addition,
The valve operation can be easily performed by crushing the elastic tube 2 of the tube pump at the position where it is pulled out from the pressing position of the pressure roller. The crushing operation at this time becomes simpler if it is performed in conjunction with the reverse rotation operation of the pump drive shaft.

FIG. 2 is an exploded perspective view for explaining an embodiment of the tube pump according to the present invention. In the figure, parts having the same functions as those of the embodiment shown in FIG. The same reference number is attached.

In FIG. 2, the pump drive shaft 30 rotatably penetrates the pump case 10 and is fixed to slide guide plates 40A and 40B described later by pins, keys and the like. As the pump guide shaft 30 rotates, the slide guide plates 40A and 40B are rotated. To rotate. As described above, the elastic tubes 2 (eight in the illustrated example) are arranged in the pump case 10. The pressure roller 20 (only one of which is shown here) has its rotary shaft 21 guided from both sides by a radial guide plate 50 having a guide groove 51 having a degree of freedom in the pump drive axis direction, and is held in the circumferential direction. , It can slide only in the pump drive axis direction.

Further, slide guide plates 40A and 40B having guide holes 41 as described with reference to FIG. 1 are mounted from both sides of the radial guide plate 50, and these guide holes 41 are attached to the rotary shaft 21 of the pressure roller 20. Hold as described above. As a result, the rotary shaft 21 of the pressure roller 20
Is held by two guide plates 40A and 40B having degrees of freedom in different directions of the guide. That is, here, the guide plate 40 is configured by the two members 40A and 40B whose guides have different degrees of freedom.

As described above, the slide guide plates 40A,
40B is fixed to the pump drive shaft 30, and the drive shaft 30
Rotate with. On the other hand, the radial guide plate 50
For the drive shaft 30 and the slide guide plates 40A and 40B, a central hole 53 is formed in the shaft 43 of the slide guide plate 40A.
It rotates freely by being fitted. However,
Stop guides 42 of slide guides 40A, 40B,
The free area in the rotational direction is regulated by the stopper 52 of the radial guide 50. That is, the slide guide 50
Is for simply guiding the pressure roller 20 in the circumferential direction.

That is, if the guide as described with reference to FIG. 1 is composed of a single guide plate, the holding of the rotary shaft of the pressure roller becomes unstable against the load due to the deformation of the elastic tube and its fluctuation. However, the configuration of FIG. 2 is very suitable because the pressure roller is supported in two different directions, the movement of the slide is not prevented, the rotation axis is not inclined, and the pressure roller can slide smoothly. . The function of the guide itself here is the same as that described with reference to FIG.

FIG. 3 is a diagram for explaining another embodiment of the present invention. In this embodiment, the tube pump 3 is composed of a plurality of (four in this case) elastic tubes 2 and the number of elastic tubes. One more (here, five) pressure rollers 20 are arranged. As the number of the pressure rollers 20 increases, the pulsation can be prevented, and the pump performance improves (the pressure and suction force increase at the same pump drive shaft rotation speed), but the location where the elastic tube is crushed is reversed. As a result, the elastic tube is likely to deteriorate, which is disadvantageous in terms of durability and the load is increased. Therefore, more torque is required to be applied to the drive shaft.

Considering continuous pumping operation for one elastic tube 2, when a certain pressure roller moves while crushing the tube, and when the pressure roller comes out of the crushing position, the next pressure is already applied. It suffices if the roller has reached the position to crush the tube. Considering this, in the pump as shown having a plurality of elastic tubes arranged so as to divide the inner peripheral surface of the pump case 10, if one more pressure roller than the number of elastic tubes is arranged, As long as the rotation of the pump drive shaft is continued, the pump will operate continuously. This is particularly effective when it is necessary to increase the pressure value, and more effect can be exhibited by combining with a valve mechanism (not shown). If pressure is required, place a valve on the O side in the figure, and if negative pressure is required on the I side in the figure, close the valve and operate the pump continuously, then open the valve. Differential pressure is applied to the supply system. At this time,
The elastic tube and the pressure roller are preferably arranged such that the circumference is equally divided. As a result, the pump can be continuously operated with the minimum necessary arrangement of the pressure roller, the load on the elastic tube can be suppressed, and the deterioration of the tube can be suppressed, so that the life of the pump is extended.

FIG. 4 is a diagram for explaining another embodiment of the present invention. In this embodiment, the tube pump 3 is
A plurality of (here, four) elastic tubes 2 and the same number of pressure rollers (four here) as the number of elastic tubes are arranged so as to divide the circumference equally. In this embodiment, therefore, even if the pump drive shaft is continuously driven, the elastic tube is not crushed by the pressure roller (at the timing shown in the figure), so that the pump operation cannot be continuously performed. For example, even if combined with valve operation, the pressure will return to the original state at the timing shown. However, when it is not necessary to increase the pressure value and only the flow rate is obtained, it can be obtained by rotating the pump drive shaft a sufficient number of times. In this case, by moving the pressure roller to a position as shown at the end of the pump operation, the pressed state of the elastic tube can be released without moving the pressure roller in the axial direction.

In addition to the above-mentioned configuration, for example, the arrangement of the elastic tube and the pressure roller need not be evenly divided on the circumference as long as the respective division angles are the same, and the number of pressure rollers is elastic. It may be less than a tube. In any case, it suffices that the position where the elastic tube is pulled out from the pump is used and the pressure roller can be moved to a position corresponding to the position when the pump is stopped.

Further, in the above description, the inner peripheral surface of the pump case is divided so that a plurality of elastic tubes are installed on one surface as the installation groove of the elastic tube of the tube pump. It is also possible to install a larger number of elastic tubes by arranging the same on a plurality of surfaces such as a stack of two or three. As the material of the elastic tube, a rubber tube such as silicon rubber or fluororubber or an elastic resin tube can be used.

[0030]

As apparent from the above description, according to the present invention, the pressure roller presses the elastic tube when the pump operation of the tube pump is stopped without increasing the space and cost with a simple structure. Can be released, and the durability and reliability of the tube pump can be improved. Since a margin is provided at the position where the elastic tube of the pressure roller is pressed, fluctuations in the load of the elastic tube,
A stable pressed state can be secured even if there is a change in the elastic force applied to the pressure roller. Since the guide is supported by two members in two different directions, the rotating shaft of the pressure roller can slide stably. Since the reverse rotation of the pump drive shaft is linked with the valve operation,
Ink does not flow back in the supply system. With the minimum required pressure roller arrangement, continuous pump operation is possible,
The load on the elastic tube can be suppressed and deterioration of the tube can be suppressed. Using the pull-out position of the elastic tube of the tube pump, the pressure roller was moved to correspond to that position when the pump was stopped,
The pressed state of the elastic tube can be released without adding a mechanism.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part for explaining an embodiment of a tube pump suitable for use in an inkjet recording apparatus according to the present invention.

FIG. 2 is an exploded perspective view for explaining another embodiment of the tube pump according to the present invention.

FIG. 3 is a view for explaining another embodiment of the tube pump according to the present invention.

FIG. 4 is a view for explaining another embodiment of the tube pump according to the present invention.

FIG. 5 is a diagram for explaining a usage example of a pump used in the inkjet recording apparatus.

FIG. 6 is a diagram for explaining an example of a conventional tube pump.

[Explanation of symbols]

1 ... Ink tank, 2 ... Ink supply tube, 3 ... Pump, 4 ... Ink jet ejection head, 5 ... Cap, 6
... waste ink tank, 10 ... pump case, 20 ... pressure roller, 21 ... pressure roller shaft, 30 ... pump drive shaft, 4
0, 40A, 40B ... Slide guide plate, 41 ... Guide hole, 50 ... Radial guide plate.

Claims (6)

[Claims] 1. An ink jet head, an ink supply system for supplying ink to the ink jet head, and a tube pump arranged in the path of the ink supply system for filling the ink jet head with ink. The tube pump is
A plurality of elastic tubes arranged so as to divide the inner peripheral surface of the pump case, a pump drive shaft, and a plurality of elastic tubes which are arranged on the circumference of the pump drive shaft as a center. A pressure roller, a guide plate that guides the rotary shaft of the pressure roller and moves integrally with the pump drive shaft, and a pump case that cooperates with the outer peripheral surface of the pressure roller to deform the elastic tube under pressure. In an inkjet head recording apparatus having a tube pump that is driven by the pump drive shaft to rotate the pressure roller so as to press the tube to perform a pump operation, when the tube pump is not used. Is
The pump drive shaft reversely rotates with respect to the rotation direction of the pump drive shaft during pump operation, and the elastic force of the tube causes the rotary shaft of the pressure roller to move in the axial direction of the pump drive shaft to move the tube. An ink jet recording apparatus, which releases the pressed state of. 2. The guide plate is provided with a guide having a region having a degree of freedom in which the rotary shaft of the pressure roller can move on the same circumference as that for pressing the tube. Item 2. The inkjet recording device according to item 1. 3. The ink jet recording apparatus according to claim 1, wherein the guide plate is composed of two members that give the rotation shaft of the pressure roller a degree of freedom in different directions of the guide. 4. An ink supply system connecting the pump and an ink jet head has a valve capable of opening and closing the ink supply system, and after the valve is closed, the pump drive shaft rotates in the reverse direction. The ink jet recording apparatus according to claim 1, wherein the pressed state of the tube is released. 5. An ink jet head, an ink supply system for supplying ink to the ink jet head, and a tube pump arranged in a path of the ink supply system and filling the ink jet head with ink, The tube pump has a plurality of (N) elastic tubes arranged so as to equally divide an inner peripheral surface of a pump case, a pump drive shaft, and a circle equally divided around the pump drive shaft. (N + 1) pressure rollers arranged in this way, a guide plate that guides the rotation shaft of the pressure roller and moves integrally with the pump drive shaft, and an outer peripheral surface of the pressure roller. And a pump case that works to pressurize and deform the elastic tube, and by driving the pump drive shaft, the pressure roller is rotationally moved so as to press the tube to perform a pump operation. An inkjet recording device characterized by the above. 6. An ink jet head, an ink supply system for supplying ink to the ink jet head, and a tube pump arranged in the path of the ink supply system for filling the ink jet head with ink. The tube pump has a plurality of elastic tubes arranged so as to divide an inner peripheral surface of a pump case, a pump drive shaft, and a number of elastic tubes equal to or less than the number of the elastic tubes on the circumference of the pump drive shaft. And a guide plate that guides the rotation shaft of the pressure roller and moves integrally with the pump drive shaft, and the elastic tube in cooperation with the outer peripheral surface of the pressure roller. And a pump case that deforms under pressure. When the pump drive shaft is driven, the pressure roller is rotatably moved so as to press against the tube to perform a pump operation, Inkjet recording, wherein the pressure roller is moved to a position which is a tube introduction part of the tube pump and is deviated from a pressure contact position of the tube when the operation is stopped, and the pressure on the tube is released. apparatus.