JP2001063082A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ink drops from being discharged from a printing head and prevent air bubbles from being sucked into the printing head in consequence of the movement of a carriage. SOLUTION: A carriage 10 is slidably supported by a guide 1 via a bearing 8. The carriage reciprocates with holding the guide 1 when printing is conducted. Inside the carriage 10 set is an ink escape part (ink pressure change-suppressing device) 20. The escape part 20 is connected to a tube 6. Ink is not filled in a stationary state of the ink escape part 20. When the carriage 10 moves left, an ink pressure at a printing head 11 increases, and therefore ink flows to the ink escape part 20, thereby easing an increased amount of the pressure. When the carriage moves right, the ink pressure at the printing head 11 decreases, and the ink having flown to the ink escape part 20 returns to the tube 6, thereby easing the pressure decrease.

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 supplies ink to a reciprocating (scanning) print head while maintaining a static pressure.

[0002]

2. Description of the Related Art FIG. 8 is a schematic diagram showing an essential part of an example of an ink jet recording apparatus to which the present invention is applied. In the drawing, reference numeral 10 denotes a carriage, and 1 denotes a reciprocating movement of the carriage 10 in the direction of an arrow. Guide 2 when making
Is a belt, and as shown in FIG.
And the carriage 10 is reciprocated along the guide 1 in the direction of the arrow. 5 is an ink tank, 6 is a tube for supplying the ink in the ink tank 5 to the ink jet print head on the carriage 10, and ejects ink droplets from the ink jet print head while reciprocating the carriage 10 in the arrow direction. , On the recording paper 7.

As described above, in an ink jet recording apparatus for supplying ink to a reciprocating carriage through a tube, an ink jet print head is mounted on a carriage 10 reciprocating along a guide 1, and an ink tank is mounted on the ink jet print head. 5 to tube 6
To feed the ink through. The tube 6 is attached to the reciprocating carriage 10 with some flexibility, and swings in accordance with the movement of the carriage 10.

FIG. 9 is a schematic diagram of the essential parts for explaining the mechanism of ink ejection by movement of the carriage. In FIG. 9, reference numeral 11 denotes an ink jet print head mounted on the carriage 10, 12 denotes ink in the tube 6, 13 Is the ink ejected from the inkjet print head 11, and in the case of the illustrated example, it is assumed that the carriage is moving from the right side to the left side in the figure. As shown in FIG. 9, when the carriage (ink jet print head) moves, the ink 12 in the tube 6 stays at the position parallel to the traveling direction of the carriage when the carriage accelerates. At this time, a flow A is generated relative to the tube 6, and the flow A increases the pressure of the ink in the ink jet print head 11, and when the pressure becomes extreme, the ink droplet 13 is discharged from the ink jet print head 11. Discharges.

[0005] Fig. 10 is a schematic diagram of the essential parts for explaining the air bubble suction mechanism by moving the carriage. In this case, the carriage moves from the left side to the right side in the figure. As described above, the carriage (ink-jet print head) moves along the guide 1, but moves in the opposite direction from that of FIG. 9 (that is, from left to right in FIG. 10). At this time, the ink 12 in the tube 6 generates a flow relative to the tube 6 in the direction indicated by the arrow B, and the ink is in a negative pressure state in the ink jet print head 11.
When the degree of the negative pressure becomes severe, bubbles 14 enter the ink from the nozzles of the inkjet print head 11. The suction of the bubbles 14 and the ejection of the ink droplets 13 occur when the pressure of the ink is larger than the surface tension of the ink on the nozzle surface.

[0006]

As described above, in an ink jet recording apparatus in which an ink jet print head is mounted on a reciprocating carriage and ink is supplied to the ink jet print head through a tube, the movement of the carriage is accompanied by the movement of the carriage. Ink droplets are ejected from the ink jet print head, and air bubbles are sucked into the ink jet print head.To prevent this, conventionally, there is a sub-tank that stores ink just before the ink jet print head By using a resin film as a diaphragm, pressure fluctuation is suppressed as described above, and ejection of ink droplets and mixing of bubbles are suppressed.

However, if the operating speed of the carriage is increased in accordance with the increase in printing speed, it is difficult to suppress a desired pressure fluctuation by the effect of suppressing the pressure fluctuation by the diaphragm. If an attempt is made to increase the effect of suppressing the fluctuation by the diaphragm, the diaphragm becomes large, and the weight of the carriage also increases.

[0008] The present invention has been made in view of the above-mentioned circumstances, and a more efficient effect of suppressing pressure fluctuations can be achieved by using a lighter device and further reducing the cost without increasing the scale. It is intended to be provided by a simple device.

In addition, the amount of movement of the carriage constantly changes depending on the printing area. In some cases, unnecessary ink flows into the pressure fluctuation suppressing device, which may cause pressure fluctuations. Another object of the present invention is to prevent a pressure fluctuation wave caused by such a suppression device.

[0010] Further, when the printing speed is further increased, it is necessary to suppress a larger pressure fluctuation and to further reduce the weight of the carriage. The present invention aims at further reducing the weight of the carriage in such a case.

Further, after the ink tank is set in the printing apparatus, there is a possibility that air bubbles are present in the tube and the inside of the head, and the ink is sucked by an external device for the purpose of removing the bubbles, or for some reason. Ink may be sucked in order to remove air bubbles mixed in the ink flow path. At that time, bubbles may remain inside the pressure fluctuation suppressing device, and it is difficult to remove the bubbles by ordinary suction.

The pressure fluctuation suppressing device according to the present invention is characterized by requiring a space in which ink can flow into the suppressing device when the internal pressure of the tube increases. , The effect cannot be expected. An object of the present invention is to improve the effect of filling ink and prevent bubbles from remaining in such a case, thereby enhancing the effect of suppressing the bubbles.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Invention of Claim 1) FIG. 1 is a schematic diagram showing a main part of the invention for explaining the invention of claim 1, wherein a carriage 10 is connected to a guide 1 via a bearing 8 as shown. And is slidably supported, and reciprocates while holding the guide 1 during printing. The carriage 10 has an ink escape portion (ink fluctuation suppressing device) 20 inside the carriage 10, and the escape portion 20 is connected to the tube 6. When the carriage 10 moves to the left in the drawing while the ink escape portion 20 is not filled with ink in a stationary state, the ink pressure in the inkjet print head 11 increases, and the ink flows into the ink escape portion 20. And mitigate the increase in pressure. When the carriage 10 moves to the right in FIG. 1, the ink pressure in the ink jet print head 11 decreases, and the ink flowing into the ink escape portion 20 returns to the tube 6 to reduce the pressure drop.

(Invention of Claim 2) FIG. 2 is a schematic view of a main part for explaining the invention of Claim 2. In this invention, the ink escape portion 20 shown in FIG. Ink fluctuation suppressing device) 21. As shown in FIG. 2, the resin bag 21 is connected to the tube 6, and is provided at the end of the carriage 10 in the advancing direction so that the ink flow caused by the operation of the carriage 10 can be efficiently received. positioned. The ink jet print head 11 includes a tube 6 connected to a resin bag 21.
It is located at the end of a tube branched into a T-shape.

As shown in FIG. 2, the carriage 10 is
From the right side to the left side, the ink inside the tube 6 flows in the direction of arrow A due to the relative inertia between the inner wall inside the tube 6 and the ink 12, and the ink 12 flows into the bag 21 as shown by the arrow C. It flows inside. Thus, the pressure of the ink 12 inside the tube 6 by the carriage 10 moved to the left in FIG. As shown in FIG. 3, when the carriage 10 moves rightward in FIG. 3, the ink 12 flows in the direction of arrow B, and the pressure in the tube 6 decreases. At this time, the ink stored in the bag 21 in the operation of FIG. 2 returns to the tube 6 so as to supplement the flow of the ink indicated by the arrow B, as indicated by the arrow D. In this way, the negative pressure inside the tube 6 is kept in equilibrium. In this way, fluctuations in the ink pressure due to the operation of the carriage 10 are reduced.

FIG. 4 is a view for explaining the operation of the above-described bag. The resin bag 21 provided at the end of the tube 6 has
A resin film 22 is provided (FIG. 4A).
When the internal pressure of the tube 6 increases and ink flows, FIG.
As shown in (B), ink is allowed while expanding. When the internal pressure of the tube 6 decreases, the ink returns to the outside of the bag 21 (that is, the tube 6) while the bag 22 returns (FIG. 4 (C)), and the pressure balance is maintained. . The ink tank 5 shown in FIG. 8 is positioned such that a negative pressure is always applied to the ink. Therefore,
When the carriage 10 is stationary, the film 22 of the bag 21 is always in a deflated state.

(Invention of Claim 3) FIG. 5 is a schematic diagram showing a main part of the invention for explaining the invention of Claim 3, and the present invention is applied to the film 22 shown in FIG. , A leaf spring 23. The operation will be described with reference to FIG. 5. Even after the carriage 10 stops and the internal pressure of the tube 6 returns to a normal value, depending on the state of the bag 21,
Ink may be drawn in. In such a case, a leaf spring 23 is applied so that the film 22 of the bag 21 is not deformed, and a forced deflation state is created as shown in FIG. So that there is no When the carriage 10 is operated, the ink flow input overcomes the force of the leaf spring 23 to crush the film 22, the film 22 expands, and the leaf spring 23
As shown in FIG. In this way, the ink pressure fluctuation suppressing device 20 prevents the internal pressure in the tube 6 from changing.

(Invention of Claim 4) FIG. 6 is a schematic view of the essential part for explaining the invention of claim 4, wherein the above-mentioned resin bag (ink fluctuation suppressing device) 21 is arranged as shown in FIG. , Arranged immediately before the ink tank 5. This position is
Since the weight of the bag 21 does not become a heavy object that hinders the movement of the carriage 10, the structure of the bag 21 does not cause a performance problem even if the weight is large. The operation is almost the same as the operation described above. When the internal pressure of the tube 6 is increased by the movement of the carriage 10, the ink flows into the bag 21 before the meniscus of the head is destroyed, and the increased pressure is absorbed by the change in volume. I do. When the internal pressure decreases, the ink stored in the bag 21 returns to the ink jet print head 11 and returns to the print head 1.
Make up for the internal pressure decrease of 1. The resistance associated with the inflow and outflow of ink can be reduced by increasing the size of the bag 21.

(Invention of Claim 5) FIG. 7 is a schematic diagram showing a main part of the invention for explaining the invention of claim 5, and the present invention, as shown in FIG.
The valve 8 is provided between the two and can be opened or closed electrically or mechanically. When the ink cartridge is attached to the printing apparatus or when the nozzle is clogged, the ink jet print head 11 is capped by the cap 30 and
The suction is performed by 1 and the ink is discharged 32. This suction,
By performing the discharging operation, the ink tank 5, the tube 6, the carriage 10, the inkjet print head 11
The air bubbles inside can also be discharged. First, the suction device 31 is driven with the valve 8 closed for a certain period of time, and the residual ink and bubbles inside the ink fluctuation suppressing device 20 are also discharged. Next, the suction device 31 is driven while opening and closing the valve 8 to completely discharge bubbles.

[0020]

(Effects of Claim 1) Claim 1
Since the ink supply device has a pressure fluctuation suppressing device that allows an ink fluctuation amount inside the carriage, the pressure fluctuation generated when the carriage is scanned is changed by changing the volume of the pressure fluctuation suppressing device. Thus, the pressure fluctuation can be suppressed and the pressure fluctuation can be suppressed.

(Function and Effect Against Claim 2) In the ink supply apparatus according to the second aspect, since the device that allows the amount of fluctuation of the ink is constituted by a resin bag, the effect of the first aspect is added. Thus, a lower-cost device can be provided.

(Effect of Claim 3) In the ink supply device of Claim 3, since a device capable of applying pressure to the device which allows the ink fluctuation amount is provided, the effect of Claim 2 is provided. In addition, optimal ink inflow can be performed depending on the amount of movement of the carriage, unnecessary ink inflow can be prevented, and pressure fluctuations caused by the device can be prevented.

(Effects of Claim 4) In the ink supply device of Claim 4, since the pressure fluctuation suppressing device is provided outside the carriage, in addition to the effects of Claims 1, 2 and 3, Even if the size of the apparatus is increased to improve the suppression effect, the weight of the carriage is not increased.

(Effect of Claim 5) In the ink supply device of claim 5, the tube has a valve, and the valve is located between the pressure fluctuation suppressing device and the ink supply tank. In addition to the functions and effects of claims 1, 2, 3, 4, and 4, the residual bubbles of the pressure fluctuation suppressing device can be discharged by operating the valve at the time of ink filling or nozzle cleaning. The ink inside the pressure fluctuation suppressing device can be discharged.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part for describing the invention of claim 1;

FIG. 2 is a diagram for explaining an example of an ink flow during a carriage operation according to the invention of claim 2;

FIG. 3 is a view for explaining an ink flow (flow in a direction opposite to that in FIG. 2) during a carriage operation according to the second aspect of the present invention.

FIG. 4 is a diagram for explaining the operation of the invention according to claim 2;

FIG. 5 is a diagram for explaining the configuration operation of the invention of claim 3;

FIG. 6 is a diagram for explaining the configuration of the invention according to claim 4;

FIG. 7 is a diagram for explaining the configuration of the invention of claim 5;

FIG. 8 is a schematic diagram of a main part for describing an example of an ink jet recording apparatus to which the present invention is applied.

FIG. 9 is a diagram for explaining an ink ejection mechanism by movement of a carriage.

FIG. 10 is a diagram for explaining a bubble mixing mechanism due to movement of a carriage.

[Explanation of symbols]

1 ... carriage guide, 2 ... carriage drive motor, 3
... Carriage drive belt, 5 ... Ink supply tank, 6 ...
Ink supply tube, 7 ... Recording paper, 8 ... Bearing, 10 ...
Carriage, 11 Printhead, 12 Ink, 13
Ink droplets, 14 ... bubbles, 20 ... ink escape portion (ink pressure fluctuation suppressing device), 21 ... bag-shaped pressure fluctuation suppressing device, 2
2. Film: 23: leaf spring, 28: valve, 30: capping section, 31: ink suction pump, 32: discharged ink.

Claims (5)

[Claims] 1. A carriage for holding a print head and reciprocating (scanning) when printing on paper, and an ink supply tank outside the carriage for supplying ink to the print head on the carriage. In an ink jet recording apparatus that supplies ink from the ink supply tank to the print head by a tube, the ink fluctuation suppressing device that absorbs an ink fluctuation amount inside the tube generated when the carriage is scanned is provided by the carriage. An ink jet recording apparatus provided above, wherein a volume of the ink fluctuation suppressing device changes according to an inflow amount of ink. 2. An ink jet recording apparatus according to claim 1, wherein said ink fluctuation suppressing device is formed of a bag. 3. The apparatus according to claim 2, wherein the ink fluctuation suppressing device formed of the bag-like body is provided with a device capable of applying a force in a direction in which the bag-like body is crushed. Ink jet recording device. 4. The ink jet recording apparatus according to claim 2, wherein the ink fluctuation suppressing device is provided outside the carriage and in a portion of the tube that does not move due to scanning of the carriage. . 5. A part of the tube that connects the ink supply tank and the print head has a valve that shuts off the flow of ink, and the position of the valve is adjusted by the ink fluctuation suppressing device on the tube. The ink jet recording apparatus according to any one of claims 1 to 4, wherein the valve is provided at an ink replenishing tank side, and the valve operates at the time of ink filling or head nozzle cleaning.