JP3358637B2 - 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 apparatus for writing a recording image such as a character on a recording medium by discharging ink droplets from nozzles, and more particularly, to an ink jet recording apparatus in which an ink tank is mounted on a carriage. Related to the device.

[0002]

2. Description of the Related Art An ink jet recording apparatus for writing information on recording paper by discharging ink droplets from nozzles is roughly divided into an ink tank provided at an appropriate position in a main body of the apparatus and a tube for supplying ink to a head unit. There are two types: a type and a type housed in a carriage on which a head unit is mounted. The latter type, in which the ink tank is mounted on the carriage, does not require the routing of the ink supply pipe, but has various restrictions on the configuration of the ink flow path in that the ink tank is installed in a limited space called the carriage. However, there is an inconvenience that it is difficult to suppress bubbles, which are easily generated when ink is supplied from the tank to the head unit, and it is difficult to remove the generated bubbles.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to make it possible for bubbles generated in an ink flow path to enter a head unit. It is an object of the present invention to provide an ink jet recording apparatus provided with a flow path structure that can be prevented from occurring.
Another object of the present invention is to provide an ink jet recording apparatus capable of suppressing the generation of bubbles as much as possible and quickly discharging the generated bubbles .

[0004] To solve such a problem, claim 1
The invention includes a carriage that reciprocates in a recording area, a head unit that is provided on the carriage and ejects ink droplets in response to a print signal, an ink tank that stores ink and is mounted on the carriage, An ink supply path connected to the ink tank, the connection member including a connection member connecting the ink tank and the head unit, the connection member including a first recess having a first taper angle;
And a first member having a second taper angle.
Ink having two recesses and connected to the head unit
A second member forming a supply path, wherein the first part
An annular recess on the inner peripheral side of a surface of the material facing the second member.
Is formed, and a flange is formed in a region facing the first and second concave portions.
With the filter member interposed, heat is generated on the outer peripheral side of the annular recess.
It is configured by welding. According to a sixth aspect of the present invention, there is provided a carriage which reciprocates in a recording area, a head unit which is provided on the carriage and ejects ink droplets in response to a print signal, and which is mounted on the carriage and supplies ink to the head unit. A first ink tank to be supplied, mounted on the carriage, and configured to connect the ink tank and the head unit, and extend substantially horizontally toward the head unit and can be attached to and detached from the head unit; An ink supply path, the ink tank and the first
A second ink supply path communicating with the ink supply path of
In order to supply the ink from the ink tank to the second ink supply path, a filter member that filters the ink is disposed in a flow path formed by forming a tapered concave portion with its expanding side opposed. A connecting member, and a cap member that is detachably attached to the head unit and communicates with the suction pump,
It comprises a first suction mode that operates intermittently and control means that drives the suction pump in a second suction mode that operates continuously .

According to the first aspect of the present invention, bubbles generated in the vicinity of the head unit after the ink tank is mounted are returned to the ink tank along the vertical tapered recess to inhibit the flow of bubbles to the head unit side. Let it. According to the invention of claim 6, ink is passed through the filter member in the rectifier state by the first suction mode suppressing generation of air bubbles in the filter member, also the generated bubbles, the filter member is accommodated
It is moved to the tank side by the inclined surface of the tapered recess being.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention. In the drawing, reference numeral 1 denotes an ink jet type head unit which is connected to an ink tank 3 via a connecting member 2 and absorbed by a foam 11 of the ink tank 3. The sucked ink is sucked out by the hollow needle 9 and, while being supplied through the ink supply passage 13 of the connecting member 2, the ink droplet is ejected in accordance with the recording signal.

FIG. 2 shows an example of the above-described head unit 1. In FIG.
This is a reservoir that receives ink supply from a riser pipe 15 connected to the pressure supply chamber 15 and supplies ink consumed in each pressure generating chamber 22 through an ink supply port 21. Each of the pressure generating chambers 22 and 2 is provided on a vibration plate 23 for sealing the pressure generating chamber 22.
The piezoelectric vibrators 24, 24, 24 ° corresponding to 2, 22 °
The tip of て is provided so as to abut. The piezoelectric vibrators 24, 24, and 24 # expand and contract in response to the recording signal to reduce and expand the volume of the pressure generating chamber 22, thereby allowing ink to be sucked from the reservoir 20 into the pressure generating chamber 22, From the nozzle opening 27 of the nozzle plate 26.

Returning to FIG. 1, reference numeral 4 denotes a cap member disposed in a non-printing area. The cap member 4 is brought into contact with the nozzle plate 26 of the head unit 1 by a driving mechanism (not shown) to open the nozzle openings 27, 27, 27.乾燥 prevents drying. The cap member 4 is connected to the suction pump 5 by a tube 12, and is configured to perform an ink suction operation by the control device 6. As the pump 5, for example, a plurality of rollers arranged so as to be on the same circumference with an interval between the supports is elastically contacted with a circularly arranged elastic tube, and the supports are unidirectionally driven by a DC motor. A so-called tube pump that rotates can be used. Reference numeral 10 in the drawing indicates a waste ink tank connected to the discharge port of the pump 5 by a tube 13.

FIG. 3 shows an embodiment of the structure of the carriage on which the above-mentioned head unit and tank are mounted. Reference numeral 30 in the figure reciprocates along a platen (not shown) guided by a guide lock 31. An ink tank holder 32 for holding the ink tank 3 is provided on the upper surface of the moving carriage.
Lever 33 which engages with the engaged portion to support and fix it
Are pivotally supported.

FIG. 4 shows a structure in which the ink tank 3 is mounted on the head unit 1 mounted on the carriage 30 via the connecting member 2.
Is capable of absorbing the positional displacement between the ink tank 40 and the head unit 20 while absorbing the positional displacement between the ink tank 40 and the head unit 1 without applying a downward force generated when the ink tank 40 is attached to the head unit 1. Is to be engaged.

As shown in FIG. 5, the connecting member 2 has a substantially U-shaped planar shape, and has leg portions 4 on both sides.
At the center of the upper surface of the main body 42 connecting the first and the first 41, a cylindrical portion 44 for receiving the communication pipe 43 of the ink tank 3 is attached. From the inner side surface 42a of the main body 42, the center of the cylindrical portion 44 is horizontally oriented. A first ink supply path 45 is provided, and a hollow needle 9 inserted into the ink supply port 42 of the ink tank 3 projects upward at the center of the cylindrical portion 44 so as to coincide with the ink supply path 45. . This hollow needle 9
Is connected to the first ink supply path 45 by a second ink supply path 47 provided vertically.

Reference numeral 51 denotes the hollow needle 9 and the second ink supply path 4.
7 is a filter member formed in a flow path connecting the SUS 7 and the SUS thin wire formed to about 2,000 mesh by twill folding, and the upper portion formed in the connecting member main body as shown in FIG. The hollow recess 9 is stretched between a downwardly expanding tapered recess 53 formed below the hollow needle 9, and connects the through hole 50 of the hollow needle 9 to the second ink supply path 47. It is disposed so as to be orthogonal to the formed vertical ink supply channel. The taper angles θ ₁ and θ ₂ of these concave portions 52 and 53 are selected to be about 30 to 60 degrees, and the function of effectively guiding the bubbles in the tapered concave portions 52 and 53 to the through holes 47 or 50 upward. It has.

FIG. 7 shows a method of manufacturing the above-described filter member 51. Reference numeral 80 in FIG.
A concave portion formed at the opening of the tapered concave portion 52 formed in 2a is selected to have a diameter capable of engaging with the bottom surface of the hollow needle 9 described later, and a tapered concave portion 52 is formed at the center of the concave portion. A ring-shaped convex portion 82 is formed in the portion 81 so as to surround the tapered concave portion 52.

The filter member 5 is attached to the ring-shaped projection 82.
1 (FIG. 1 (I)), and in this state, the filter member 5 is placed.
When the heat source is pressed against the convex portion 82 via 1, the molten portion 82 ′ of the convex portion 82 is selectively melted and penetrates into the gap of the mesh of the filter member 51 (FIG. (II)).

On the other hand, the hollow needle 9 has a flange 86 in contact with the upper surface 87 of the connecting member 42 near the bottom 85 that can be fitted into the concave portion 80 of the connecting member 42. On the bottom surface of the flange 86, an annular groove 88 is formed on the inside, and an annular protrusion 89 having a V-shaped cross section is formed on the outside.

The hollow needle 9 is inserted into the concave portion 52 where the filter member 51 is welded (FIG. 3 (III)), and the flange 8 is inserted.
When the ultrasonic wave is applied to 6, the projection 89 having a V-shaped cross section is selectively melted and welded to the connecting member main body 42. In the melting process, the surplus flows into the annular groove 88 and does not protrude outside. Thereby, the filter member 51 is air-tightly fixed between the connecting member 42 and the hollow needle 9.

Returning to FIG. 5, positioning dowels 90, 90 are formed at the intermediate portions inside the legs 41, 41 on both sides of the connecting member 42, and the projecting portions on both sides of the head base 91 are formed. The holes 93, 93 provided in the holes 92, 92 are fitted to the positioning dowels 90, 90, and both are integrally fixed by screws 94, 94.

One end of the rising tube 15 of the head unit 1 faces the head base 91 at a position corresponding to the ink through hole of the connecting member 2. The first ink supply path 45 is connected to an elastic joint 95.
Connected through. Reference numeral 97 in the figure indicates a circuit board fixed to the upper surface of the head base.

In this embodiment, the ink tank 3 is
When the lever is set down on the carriage 30 and the lever 33 is lowered, the hollow needle 9 falls into the communication pipe 43 of the ink tank 3. In this state, the cap member 4 is attached to the head unit 1,
When the pump 5 is operated, the suction force of the pump 5 acts on the nozzle openings 27, 27, 27 # via the cap member 4. This negative pressure acts on the ink tank 3 via the first ink supply path 45, the filter member 51, the second ink supply path 47, and the hollow needle 9, and the ink absorbed by the foam flows into these flow paths. . When a predetermined time, for example, 0.1 to 1 second has elapsed, the pump is temporarily stopped to stop the suction operation. After a lapse of a predetermined time, for example, 0.1 to 1 second, the pump 5 is operated again to suck ink from the foam 11.

By intermittently driving the pump 5 in this manner, the speed of the ink flowing through the ink supply path is suppressed to V1, for example, 1 mm / sec or less, and the flow rate is suppressed to an extremely low value of 0.01 cc / sec or less. Is rectified and passes through the filter member 51.
Is prevented from foaming due to the mesh. Note that even if bubbles are generated at this time, the bubbles F (FIG. 9A) pass through the mesh of the filter member 51 while being crushed (FIG. 9B), and the fine bubbles f, f, f ‥‥, and flows into the head unit 1 from the ink supply path 47 ((c) in the figure).

By performing such a suction operation intermittently a plurality of times, ink is filled in the flow path from the ink tank 3 to the head unit 1 while preventing foaming as much as possible. When the ink has flowed from the ink tank 3 into all the flow paths of the head unit 1 in this manner, the pump 5 is continuously operated for 2 to 10 seconds, that is, the flow rate of the ink is V2, specifically, about 0.2 cc. If the suction is continued at a high flow rate of / sec, the ink becomes a high-speed flow of the speed V2, flows from the tank 3 to the head unit 1, and adheres to the small bubbles flowing into the head unit 1 and also to the wall surface of the flow path. The flowing bubbles are caused to flow toward the recording head 1 by the high-speed flow,
The ink is discharged from the nozzle opening 27 to the cap member 4. Even if the ink is filled by the high-speed flow, no bubbling occurs since the ink from the ink tank 3 to the nozzle opening is already filled with the ink.

When a recording signal is output to the head unit 1 at the stage when ink filling is completed, ink droplets are ejected onto recording paper in accordance with the recording signal by a known operation. The ink consumed by the head unit 1 is replenished from the tank 3 to the head unit via the ink supply path.

As described above, since the ink flow velocity at the time of initial filling is set to be extremely small, bubbling in the ink flow path can be suppressed even when no liquid exists in the ink flow path. For this reason, it is possible to eliminate the need for the filling liquid previously filled in the ink flow path of the head unit at the time of shipment from the factory, and further, when the ink tank filled with the ink that has not been subjected to the degassing process is installed. Also, no bubbles remain after filling.

In the process of refilling the ink, the bubbles flowing from the tank 3 into the hollow needle 9 move upward along the tapered wall surface 53a of the concave portion 53 constituting the filter chamber (FIG. 9).
(D), it does not flow into the ink supply path 45 extending in the horizontal direction. Further, small pieces, dust, and the like of the foam 11 flowing out of the ink tank 3 are interrupted by the filter member 51 and do not flow into the head unit 1.

The effect based on the intermittent driving of the suction pump is maximized by setting the suction stop period to about 0.2 to 0.5 seconds.

When the ink tank is replaced at the stage when all the ink in the tank 3 has been consumed by printing, the controller 6 causes the ink to be transferred from the tank to the head unit 1 in the first and second suction modes described above. Fill.

[0027]

As described above, according to the first aspect of the present invention, air bubbles generated in the ink flow path connecting the head unit and the ink tank enter the head unit through the first ink supply flow path. And returning to the ink tank by the inclined surface of the tapered recess, thereby preventing the inflow into the head unit. Further, according to the invention of claim 6, when filling the head unit with ink after the ink tank is mounted, first, the ink is allowed to pass through the filter member in a rectified state by the first suction mode, thereby suppressing generation of bubbles by the filter member. In addition, the bubbles can be moved to the tank side along the slope of the tapered recess to prevent the bubbles from flowing into the head unit .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an ink supply system of an ink jet recording apparatus of the present invention.

FIG. 2 is a view showing one embodiment of a head unit used in the above device.

FIG. 3 is a perspective view showing a state of being mounted on a carriage.

FIG. 4 is a sectional view showing one embodiment of a head unit used in the present invention.

FIG. 5 is an exploded perspective view mainly showing a connecting portion.

FIG. 6 is an enlarged sectional view showing a filter member.

FIGS. 7 (I) to (III) are views showing steps of manufacturing a filter member. FIGS.

FIG. 8 is a diagram showing an operation and a flow rate of a pump in an ink filling step of the printer.

FIGS. 9A to 9D are explanatory views showing the state of ink flow and air bubbles flowing through a filter, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head unit 2 Connecting member 3 Ink tank 4 Cap member 5 Suction pump 6 Control device 9 Hollow needle 26 Nozzle plate 51 Hollow needle 52, 53 Tapered through hole f, F Bubbles

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-92356 (JP, A) JP-A-4-73159 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/165 B41J 2/175 B41J 2/18 B41J 2/185

Claims (7)

(57) [Claims] A carriage that reciprocates in a recording area; a head unit that is provided on the carriage and ejects ink droplets in response to a print signal; an ink tank that stores ink and is mounted on the carriage; A first connecting member for connecting the ink tank and the head unit, wherein the first connecting member includes a first concave portion having a first taper angle and forms an ink supply path connected to the ink tank. And a second concave portion having a second taper angle and forming an ink supply path connected to the head unit.
An annular concave portion is formed on an inner peripheral side of a surface of the first member facing the second member, and a filter member is interposed in a region opposed to the first and second concave portions. An ink jet recording apparatus which is mounted and thermally welded on the outer peripheral side of the annular concave portion. 2. The method according to claim 1, wherein the first taper angle and the second taper angle are 3
2. The ink jet recording apparatus according to claim 1, wherein the angle is 0 to 60 degrees. 3. The ink jet recording apparatus according to claim 1, wherein the first ink supply path is disposed substantially perpendicular to the filter member. 4. The ink jet recording apparatus according to claim 1, wherein the first ink supply path is constituted by a hollow needle that can be inserted into the ink tank. 5. The ink jet recording apparatus according to claim 1, wherein the filter member is disposed horizontally. 6. A carriage reciprocating in a recording area, a head unit provided on the carriage for ejecting ink droplets in response to a print signal, and an ink mounted on the carriage and supplying ink to the head unit. A first ink supply path mounted on the carriage and configured to connect the ink tank to the head unit, extending substantially horizontally toward the head unit, and detachable from the head unit; A second ink supply path for communicating the ink tank with the first ink supply path, and a tapered recess for supplying ink from the ink tank to the second ink supply path. A connecting member comprising: a filter member for filtering the ink disposed in a flow path formed with the open sides facing each other; A cap member detachably connected to the suction pump and communicating with the suction pump, a first suction mode that operates intermittently, and control means that drives the suction pump in a second suction mode that operates continuously. Ink jet recording device. 7. The ink jet recording apparatus according to claim 1, wherein the filter member is constituted by a filter of about 2,000 mesh formed by folding a stainless steel wire.