JP3374895B2 - Ink jet recording device - Google Patents

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 method in which an ink jet recording head is mounted on a carriage, an ink cartridge is mounted on a box, and ink is supplied from the ink tank to the recording head via a tube. Regarding the device.

[0002]

2. Description of the Related Art An ink jet recording apparatus is equipped with an ink jet recording head for ejecting ink droplets by a pressure generating means on a carriage and performs printing while receiving ink supply from an ink tank. Also equipped with an ink cartridge on the carriage,
The structure is being simplified. On the other hand, as the performance of inkjet recording heads has improved dramatically, the dot density has dramatically increased, enabling color printing in natural colors, and in order to further improve print quality, blurring on the recording medium is avoided. Efforts are being made to make it as small as possible. As one of the means, a method has been proposed in which an ink is made to contain an emulsion or sugar to form an ink droplet on a recording medium. In the ink having such a film-forming property, there is a high possibility that the porous body, which is inevitably necessary for the on-carriage type cartridge, obstructs the flow of the ink to the recording head. As shown in / 31335, the ink jet type recording head and sub tank are mounted on the carriage, the ink in the ink cartridge is pressurized by air to pass through the recording head, and then supplied to the sub tank. Air bubbles and high-concentration ink near the nozzle openings are forcibly discharged to the sub-tank, and the thickened ink in the sub-tank is mixed with the ink supplied from the ink cartridge to dilute it to a density suitable for printing. It has been proposed to supply the printhead to a recording head for printing.

[0003]

When the ink having such a film-forming property is left in a non-printing state, the ink film is naturally formed in the nozzle openings, and the ink film functions as a lid. During the period of about 8 hours, the ink film can be removed by pressure-feeding the ink to the recording head, and printing is possible.

However, even if a small amount of ink leaks in the capped state, and if left in this state for a long time, the ink will solidify and the cap member will be difficult to separate. Need to be sealed.

Further, when the bubbles discharged to the sub tank are discharged to the outside through the gas selective valve, it is necessary to seal the recording head with a pressure such that ink does not leak from the recording head. Is to reduce the abrasion of the surface treatment material of the nozzle plate as much as possible when the recording head is rubbed by the cap member for maintenance.
It is necessary to press the cap member with extremely weak pressure.

On the other hand, when the ink is supplied from the ink cartridge to the recording head or the sub-tank, the pressure is relatively high enough to remove the ink film formed in the nozzle opening and to discharge the air from the sub-tank. Since two types of pressure, that is, a relatively low pressure that does not affect the meniscus of the nozzle opening, are required, an air supply mechanism is required when at least four types of cartridges are required such as color printing. There is the problem of complication.

The present invention has been made in view of the above problems, and an object of the present invention is to supply the ink of an ink cartridge to a sub-tank through the recording head and from the sub-tank to the recording head. To provide a recording apparatus including a unitized capping mechanism and an air supply system suitable for an ink supply system that causes ink to flow back into a cartridge.

[0008]

In order to solve such a problem, in the present invention, a sub-tank and an ink jet type recording head mounted on a carriage moving in parallel to a platen, and the recording head outside the carriage. An ink cartridge that communicates with a tube, an air pump that supplies air for ink discharge to the ink cartridge through a pressure adjusting unit, and a capping unit that seals a nozzle opening of the recording head outside the printing area of the carriage, In an ink jet recording apparatus that supplies the ink of the ink cartridge to the sub-tank through the recording head and backflows the ink from the sub-tank to the cartridge through the recording head, the capping means includes a plurality of springs. Due to the urging force of Pressing force is adjusted relative to the head,
Further, the pressure adjusting means adjusts the pressure of the air supplied to the ink cartridge in association with the pressing force of the capping means.

[0009]

The pressing force can be adjusted only by selecting the action points of a plurality of springs by the cam, and the recording head is released from the capping means by adjusting the pressure of the pressure adjusting means in conjunction with the cam. In some cases, the air having a medium pressure, which is sealed by the capping means and has a pressure required to remove bubbles from the sub tank, is automatically selected.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments. FIG. 1 shows an embodiment of the ink jet recording apparatus of the present invention,
The carriage 1 is supported by a guide member 2 and is connected to a carriage drive motor 4 via a timing belt 3.
It is configured to reciprocate parallel to the platen 5.

The carriage 1 receives ink from a plurality of, in this embodiment, four ink jet recording heads 6, 7, 8, 9 and an ink supply unit 10 described later on the side facing the platen 5, and the recording heads. Sub tanks 11, 12, 13, and 14 for supplying to

One end of each of the sub-tanks 11 to 14 is connected to an ink cartridge 15, 16, 17, 18 to be described later, and ink tubes 20, 21, 22, in which inks to be supplied to the recording head are colored in a similar color. 23 is connected.

At the home position of the carriage 1, a unit 28 in which a capping member 25, an air pump 26, and a pressure adjusting valve 27, which will be described later, are incorporated in a frame is arranged. Reference numeral 29 in the drawing denotes a cassette for stocking the recording paper 30, and 31 denotes an idle pulley provided at one end of the frame 32.

As shown in FIG. 3, the recording apparatus having the above-described structure includes the ink pack 1 of the ink cartridge 15.
The ink supply port 15b of 5a and one ink outflow port 6a of the recording head 6 are connected by a tube 20, and the other ink outflow port 6b and the sub tank 11 are connected.

On the other hand, the pressurizing space 15c of the ink cartridge 15 is supplied with air from the air pump 26 via a pressure adjusting valve 27 which can set the pressure in two stages, high and low, which will be described later.

With such a flow path structure, air is supplied to the pressurizing space 15c of the cartridge 15 to supply the ink bag 15a.
When the pressure is applied, the ink in the ink bag 15a is removed from the tube 20.
Through an ink outflow port 6a located below the recording head 6 through a common ink chamber or pressure generating chamber in the recording head and the other ink outflow port 6b through the sub tank 11
Flow into.

Bubbles remaining in the common ink chamber and the pressure generating chamber are discharged to the sub tank 11 by this flow of ink. When the ink in the sub tank 11 is replenished and the pressure in the space of the sub tank 11 rises, only air is released from the air vent valve 11a to the atmosphere. When the sub tank 11 is filled with ink up to the ink full state, a signal is output from the ink full sensor 11b, the air pump 26 is stopped, and the air vent valve 11a is closed.

The ink in the sub tank 11 is used for the recording head 6.
The water flows back to the ink cartridge 15 through the recording head 6 through the tube 20 by the head pressure based on the difference in height between the ink cartridge 15 and the cartridge 15. When the back flow to the ink cartridge 15 progresses and the amount of ink in the sub tank 11 decreases,
Since the ink-empty sensor 11c outputs a signal, the air pump 26 operates and the ink cartridge 15
Then, the sub tank 11 is replenished with ink via the recording head 6 again, and when the ink is full, the air supply from the air pump 26 is stopped.

Hereinafter, each time the ink in the sub-tank 11 flows backward and decreases, the above-described ink replenishment is performed, and the sub-tank 15 and the ink cartridge 15 are repeatedly reciprocally circulated via the recording head 6 to repeat the recording head 6. The operation of maintaining the density of the ink at the optimum value for printing is performed.

Next, the unit 28 described above will be described. The cap member 24 elastically contacting the nozzle openings of the recording heads 6 to 9 is made of silicon rubber having chemical resistance, and is aligned with the arrangement pitch of the nozzle opening rows of the recording heads 6 to 9 as shown in FIG. Multiple protrusions 2 to match
4a, 24a, ... And downwardly extending tongue portions 24b, 24b for guiding the ink to the center of the concave portion between the convex portions 24a.
, And ribs 24c, 24c for keeping the convex region as flat as possible are formed on both sides.

The cap member 24 is detachably attached to a surface of a support member 38 provided on a shaft 37 which is constantly urged toward the recording head 6 by a spring 36 in a cap holder 35 described later.

The cap holder 35 is formed by forming a substantially quadrant cam floor 40 in the center, and one end thereof is attached to a long hole of the frame by a shaft 41 so as to be horizontally movable and rotatable. The coil spring 42 constantly urges the recording head side upward.

The cam follower 40 is provided with a first cam 43, and rotation of the cam 43 causes the cap holder 3 to rotate.
5 is moved vertically and horizontally. The second cam 45 is fixed to the shaft 44 of the first cam 43 and presses the other end of the coil spring 46 whose one end is fixed to the cap holder 35.

On the other hand, the recording head side is fixed to the shaft 47,
A cap member pressing lever 48, which is rotatably provided on the frame via this shaft, selectively contacts the supporting member 38 and presses the cap member 24 with a strong pressure of the coil spring 49.

The other end of the lever 48 is provided with a pin 53 which is in contact with a half-moon cam 50 and which engages with a claw 52 which is pulled upward by the urging of a solenoid 51.

On the side facing the carriage 1, there is provided a lock lever 54 in which a pawl 54a is constantly urged downward by a spring (not shown), and is engaged with a lever 55 which is rotated by a shaft 47 fixed to a lever 48. I am fit.

When the power is turned on, the cam 50 rotates to raise the pin 53 to the uppermost end, and the solenoid 51 urged by turning on the power causes the pin 52 to move to the side of the cam 50. 53 is engaged (FIG. 4 (b)). As a result, the lever 48 is separated from the shaft 37, and the cap member 24
Push the release of the of the strong spring 49 by that the recording head 6 to
Further , the pawl 54a of the lock lever 54 is separated from the recess 1a of the carriage 1 by the rotation of the lever 48, and the carriage 1 is unlocked.

In this state, the tip end 43a of the first cam 43 is
Is separated from the cam floor 40, the cap holder 35 is positioned by the spring 42 at the recording head side and at a fixed upper position (FIG. 6 (I)). In this state, the tip end 45a of the second cam 45 presses the spring 46,
The cap member 24 is pressed against the recording head 6 with a force determined by the elasticity of the spring 46, for example, about 400 grams. Therefore, even if the ink cartridges 15 to 18 are pressurized with a pressure that can remove the bubbles in the sub tanks 11 to 14, it is possible to prevent the ink from leaking from the recording heads 6 to 9.

When the second cam 45 is separated from the spring 46 by the rotation of the shaft 44 (FIG. 6 (II)), the cap member 24 is removed by a small pressure only by the spring 36 provided on the shaft 37, for example, about 100 grams. The recording heads 6 to 9 are pressed.

When the shaft 44 further rotates, the first cam 4
The lower surface 40a of the cam follower 40 is pushed by the side surface 43b of the No. 3 side. In this state, the cap member 24 is in parallel with the surface of the nozzle plate because the tip end surface of the convex portion 24a is elastically contacted with the nozzle plate of the recording head 6 and the rear end is swingably supported by the shaft 37. It moves downward (Fig. 6 (III)). The protrusion 24a of the cap member 24, which receives the pressing force of the spring 36 due to the lowering of the cap member 24, rubs the recording heads 6 to 9 without abrading the processing layer.

Further, when the first cam 43 rotates, its tip 43a abuts on the lower surface of the cam floor 40, and the upper end of the cap member 24 comes in contact with the lower end of the recording head 6 while being pressed by the spring 36 ( FIG. 7 (I)). In this state, the air pump 26 is operated to operate the ink cartridge 1
When ink is supplied to the recording head 6 from 5 until the sub tank 11 is full of ink or more, obstacles such as ink residues of the nozzle openings that cause clogging of the nozzle openings can be discharged together with the ink.

The ink flowing out from the recording head 6 flows through the region of the cap member 24 where the convex portion 24a is formed, is guided by the lower tongue piece 24b, and is discharged into the waste ink tank 5.
It falls to 6.

When the first cam 43 is further rotated, the tip of the cap holder 35 is further lowered, while the cap member 24 receives the low pressing force of the spring 36 and the upper slope 2
4d moves to the lower side on the recording head side while abutting the lower end of the recording head 6, and projects forward from the nozzle plate surface of the recording head (FIG. 7 (II)). In this process, the ink that has flowed out and adhered to the lower ends of the recording heads 6 to 9 m due to the operation for recovering the ink ejection capacity has an upper slope 2 of the cap member 24.
It is scraped off in 4d.

When the cam 43 further rotates and moves to the lower portion of the rear end of the cam follower 40, the cap holder 35 is pushed backward against the spring 42 and moves backward, so that the cap member 24 is opened by the nozzle opening of the recording head 6. A constant gap ΔG1 is formed from the surface (FIG. 7 (III)).

When the cam 43 is further rotated at the stage where the ink ejection capacity recovery operation is completed, the cap holder 35 is rotated.
While pushing backward (Fig. 8 (I)), the cam follower 40
When the stable point 40b formed on the rear end wall is reached, the cap holder 35 forms a constant gap ΔG2 with the recording head 6, and a horizontal posture is secured to enable printing (FIG. 8 ( II)).

Then, since the operating rod 58a of the limit switch 58 falls into the concave portion 511a of the cam 57 provided on the shaft 44, a signal is output from the limit switch. This signal is output to a control device (not shown) so that the print routine can be started.

When the cam 43 further rotates, the tip end 43a of the first cam 43 separates from the cam follower 40a, so that the cap holder 35 is pulled up by the spring 42.
As a result, the cap member 24 rises to a position corresponding to the recording head 6, and when the shaft 44 further rotates in this state, the second cam 45 presses the spring 46, and therefore, FIG.
Returning to the state of (I), the cap member 24 is pressed by the medium pressure of the spring 46 to seal the recording head 6.

In this state, when the power is turned off, the solenoid 51 is deenergized, the claw 52 retracts, the pin 53 becomes free, and the lever 48 descends due to the urging force of the spring 49, as shown in FIG. In this state, the cap member 24 is pressed against the recording head 6 by the strong force of the spring 49, and the lock lever 54 engages with the recess 1a of the carriage 1 to lock the carriage 1.

As a result, even if a large hydraulic head pressure acts on the recording head between the recording heads 6 to 9 and the sub tank 11 due to the posture of the recording apparatus due to movement or the like, ink leakage from the recording head 6 or the carriage 1 may occur. The unintentional movement of is surely prevented.

On the other hand, as shown in FIGS. 3, 9 and 10, the pressure adjusting valve 26 has a donut-shaped pressure adjusting chamber 61 on one side surface of the base body 60 and an atmosphere opening port 62 at the center. A valve portion is formed by sealing the open surface of the pressure regulating chamber 61 with a diaphragm 63. The diaphragm 63 has a spring 66 whose one end is rotatably supported by a shaft 64 in its central region, and one end of which is fixed to a lever 65 whose expansion angle is limited, and one end of which can be rotated by the shaft 64. And a lever 68 that is constantly urged toward the diaphragm side by a spring 67 that is hung between the frame and the frame and is elastically pressed against the atmosphere opening port 62.

The lever 68 is connected to the other end of the lever 70 which is moved forward and backward by a cam 69 having one end fixed to the shaft 44, and the lever 70 is moved according to the operation of the capping mechanism.
Is moved to selectively apply and release the biasing force of the spring 67.

The pressure adjusting chamber 61 is provided with a plurality of, in this embodiment, four outlets 71, 72, 73 and 74, and a valve 75 whose opening and closing is controlled by cams 90, 91, 92 and 93 which will be described later.
Tubes 79, 80, 81 via 76, 77, 78,
82, ink cartridges 15, 16, 17, 18
Are connected to the pressurizing chambers 15c, 16c, 17c and 18c. The tubes 79 to 82 are colored to be similar to the ink colors of the ink cartridges 15 to 18, respectively.

The valve elements 75a to 78a of the valves 75 to 78 are constantly urged in the valve opening direction by springs, and the springs 86, 78 are urged via one arm of an L-shaped lever 83 having independent operating rods. 87, 88, 89 are constantly urged in the valve closing direction.

A cam floor is formed at the tip of the other arm of the lever 83, and the entire circumference is equally divided into 32 regions by a modified sinusoidal curve, and four cam plates 90 are formed with recesses at predetermined positions. , 91, 92, 93 are fixed to the rotary shaft 94 by shifting the phases, respectively, and all valves are simultaneously opened / closed, three valves are simultaneously opened, and two valves are simultaneously opened, as shown in Table 1. It is configured to realize valve opening and 16 types of opening / closing patterns that enable opening of one valve.

[0045]

[Table 1]

With such a configuration, the sub tank 11,
Ink is supplied to all of 8, 9, and 10 at the same time, or the supply of ink to all the sub-tanks 11 to 10 is stopped, and further, one to three sub-tanks 11 to 1 are used.
Even when signals are simultaneously output from the ink full sensor of 0 and the ink end sensor, it can be dealt with by selecting the rotational position of the cam.

The air pump 26 is constructed as a diaphragm pump and is driven by a cam mechanism 101 which receives power from a drive source via the train wheel 100.

Then, in a state where the cap member 24 is pressed by the second lever 45 and the recording head 6 is sealed by the spring 46 at an intermediate pressure, the lever 70 as shown in FIG.
Is moving to the carriage side, the diaphragm 63
Is pressed against the atmosphere opening port 62 by the strong pressure of the spring 67.

Therefore, the cam plates 90, 91, 92, 93
When the valves 75 to 78 are opened by the above, high pressure air is supplied to the ink cartridges 15 to 18 and ink is not leaked from the nozzle openings, and the sub tanks 11 to 1 are opened.
It is possible to supply the ink to No. 4 with a pressure that can eliminate bubbles.

On the other hand, when the recording head 6 is unsealed from the cap member 24, a cam fixed to the shaft 44 for driving the first and second levers 43 and 45 as shown in FIG. Since the lever 70 is retracted to the pressure regulating valve side by 69 and the pressing force of the spring 67 is received by the lever 70, the diaphragm 63 is pressed against the atmosphere opening port 62 by the weak pressure of the spring 66. Therefore, the ink cartridges 7 to 10 can be pressed with a pressure that can cope with the ink consumption of the recording head 6 due to printing.

[0051]

As described above, in the present invention,
A sub-tank and an inkjet recording head mounted on a carriage that moves parallel to the platen, an ink cartridge that communicates with the recording head by a tube outside the carriage, and air for discharging ink to the ink cartridge through a pressure adjusting unit. An air pump, a capping unit that seals the nozzle opening of the recording head outside the print area of the carriage, and the ink in the ink cartridge is passed through the recording head and supplied to the sub-tank. In an ink jet type recording apparatus that causes reverse flow of ink, the capping means adjusts the pressing force against the recording head by the urging force of a plurality of springs, and the pressure adjusting means interlocks with the pressing force of the capping means and supplies the air pressure to the ink cartridge. Key Since so as to, it is possible to select a sealing force only in the recording head be selected by cam action point a plurality of springs, the supply pressure of ink to the sub tank.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a side view of the same recording apparatus.

FIG. 3 is a diagram showing an example of an ink supply system of the recording apparatus.

4A and 4B are views showing an example of a capping mechanism of the same apparatus in a state in which a recording head is sealed and in a printable state, respectively.

FIG. 5 is a perspective view showing an embodiment of a cap member of the same capping device.

FIGS. 6 (I) to (III) are explanatory diagrams showing a process of moving the ink supply state to the sub tank to a rubbing operable state in the operation of the capping mechanism of the above.

7 (A) to 7 (I) are explanatory views showing a process in which the cap member moves to the lowermost end from the operation of recovering the ink ejection capability in the operation of the capping mechanism of the above.

8 (I) to (II) are explanatory views showing a process of moving to a printable state in the operation of the capping mechanism of the above.

9 (a) and 9 (b) are respectively a top view and a side view showing an embodiment of a pressure adjusting valve of the same recording apparatus in a state of being set to a high pressure state.

10A and 10B are a top view and a side view, respectively, showing an embodiment of a pressure regulating valve of the recording apparatus in the same state when set to a low pressure state.

[Explanation of symbols]

1 carriage 5 Platen 6-9 Inkjet recording head 7-10 sub tanks 15-18 ink cartridge 24 Cap member 26 Air pump 27 Pressure control valve 35 cap holder 40 Cam Follower 43 First Cam 45 second cam 36, 46, 49 Spring for pressing cap member 48 Lever for pressing cap member 50 Cap member push lever lifting cam 51 solenoid 52 nails 54 Carriage claw

Claims (8)

(57) [Claims] 1. A sub-tank and an ink jet recording head mounted on a carriage that moves in parallel with a platen, an ink cartridge communicating with the recording head by a tube outside the carriage, and an ink cartridge connected to the ink cartridge via a pressure adjusting means. An air pump that supplies air for discharging ink, a capping unit that seals a nozzle opening of the recording head outside the printing area of the carriage, and ink of the ink cartridge that passes through the recording head and is supplied to the sub tank. In an ink jet recording apparatus that causes ink to flow back to the cartridge from the sub-tank via the recording head, the capping means adjusts the pressing force against the recording head by the urging force of a plurality of springs, and the pressure adjustment. The means is An ink jet recording apparatus in conjunction with the pressing force of the mappings means for adjusting the pressure of air supplied to the ink cartridge. 2. The capping means has the one end described above.
A cap holder supported by a long hole substantially perpendicular to the surface of the recording head, and a first spring on the upper part of the cap holder.
An attached cap member and a second spring that is provided below the cap holder and is stronger than the first spring.
And a first cam that is in contact with the second spring, and is movable in the vertical direction and the horizontal direction. The first cam allows the cap to be moved via the second spring.
The recording material to the recording head,
Front via second spring by second cam interlocking with cam
Note that the cap member is pressed with a force weaker than that of the first cam.
Press on the recording head, and further on the cap member pressing lever
The cap member with a stronger force than the first cam.
The ink jet recording apparatus according to claim 1, which is pressed against the recording head . 3. The cap member pressing lever is used to
The inkjet recording apparatus according to claim 2, wherein a claw that engages with the carriage when the cap member is pressed by the recording head is provided at the tip of the cap holder . Wherein said cap member pressing lever, the calibration by the electromagnetic means in the power-on state is always biased
The cap member is held at a position separated from the recording head, and when the power supply is cut off, the cap member
The ink jet recording apparatus according to claim 2, wherein the cap member is pressed against the recording head by an urging force of a third spring connected to the pressing lever . 5. An upper surface of the cap member is formed with a sloped surface whose upper side is retracted from the recording head.
The cap member contacts the lower end of the recording head following the movement of the cap holder by the guide of the inclined surface portion.
An ink jet recording apparatus according to claim 2 for scraping ink of the lower end of the recording head while moving while. Wherein said pressure adjusting means comprises a first valve separating the pressure regulating chamber and the air release <br/> port, the first to the atmosphere opening port
A first spring for pressure adjustment that constantly presses the valve;
Push to the recording head of the cap member by the cam
At the time of basing, the force of the first spring is stronger than that of the first spring .
The ink jet recording apparatus according to claim 2, wherein the ink jet recording apparatus comprises a lever that presses a valve . 7. The ink jet system according to claim 6, wherein the pressure adjusting unit has a second valve that is opened and closed by a cam plate, and is connected to the ink cartridge through a tube via the second valve. Recording device. 8. The ink cartridge is attached to the tube.
8. The ink according to claim 7, which is colored in a color similar to the color of the ink.
The ink jet recording apparatus according to item 1.