JP3431056B2 - 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 type recording apparatus having a recording head which moves in the width direction of a recording sheet and ejecting ink droplets onto the recording sheet in conformity with print data to form an image. The present invention relates to a capping device suitable for a recording device equipped with a head.

[0002]

2. Description of the Related Art An ink jet type recording apparatus for recording print data by ejecting ink pressurized in a pressure generating chamber as ink droplets from a nozzle onto a recording paper is known as an ink jet recording apparatus. In order to prevent an increase in viscosity, for example, as seen in Japanese Patent Laid-Open No. 9-39258, it is arranged outside the printing area and pressed by the recording head or the carriage that carries it to match the movement of the carriage on the base. A slider that follows the movement of the carriage while moving up and down, and a cap that is urged toward the recording head by an elastic member and is swingably attached to the slider via a support frame are provided. A capping device that presses the raised cap against the recording head to seal the cap is provided.

The capping device has a function of sealing the nozzle openings during non-printing to prevent the ink solvent from drying, and
When the nozzle opening is clogged, it is also used for the ejection capacity recovery operation in which the recording head is sealed by the capping device and the negative pressure of the suction pump is applied to the nozzle opening to forcibly discharge the ink. When a large amount of ink is discharged from the nozzle opening in this way, the ink D is held by the capillary force in the narrow gap formed by the fold portion B of the cap A and the nozzle plate C as shown in FIG. It When attempting to release the sealing of the recording head by the capping device in this state, the ink D becomes a thin film E between the cap A and the nozzle plate C as shown in FIG.
Lastly, there is a problem in that the ink droplets flies and scatters as minute ink droplets and adheres to the vicinity of the nozzle openings, resulting in deterioration of print quality.

[0004]

This problem is solved by absorbing the ink contained in the cap A in order to keep the inside of the cap always wet and prevent the ink from rebounding due to ejection of ink droplets due to flushing or the like. Sheet F
The ink is collected in the protrusion G formed on the inner peripheral surface of the cap A for the purpose of holding the ink inside the cap, and the ink spreads between the nozzle plate C and the fold portion B by the capillary force. There is. In order to solve such a problem, in the invention described in the above publication, a tongue piece is formed on the peripheral portion of the ink absorbing sheet so that the ink that collects between the ink absorbing sheet and the recording head during capping is absorbed by the tongue piece. However, there is a problem that ink mist is still generated when the cap is opened because the area where the tongue can be formed is limited. The present invention has been made in view of such circumstances,
It is an object of the present invention to provide an ink jet recording apparatus capable of preventing ink from stagnating between a recording head and a cap and reliably preventing ink mist from being generated when the cap is opened.

[0005]

In order to solve such a problem, the invention of independent claim 1 of the present invention is an ink jet type recording head for ejecting ink droplets from a nozzle opening by a drive signal, and an inner peripheral surface. the ink jet recording apparatus provided with a capping device comprising a cap for holding said ink absorbing sheet by a projection and Lee ink absorbing sheet which is formed in tongue that is, the ink on the projection
A groove having a width that allows the ink to be sucked by a capillary force is formed , and the amount of ink stagnant in the protrusion is reduced as much as possible. Also independent
According to the invention of Item 2, the ink droplet is ejected from the nozzle opening by the drive signal.
Inkjet recording head that ejects
The protrusions and the tongues formed on the ink absorption sheet
It consists of a cap that holds the ink absorption sheet
Inkjet recording apparatus provided with capping device
In, the width a of the protrusion in the peripheral direction of the cap
Is smaller than the distance e to the sealing surface d, e
> √ [{8-a2 (1-cos θ)} / {4 (1-cos
θ)}] (where e is the distance from the sealing surface and θ
Represents the wetting angle), and
Ink rise is suppressed as much as possible.

[0006]

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 present invention, in which reference numeral 1 is a carriage, which is connected to a motor 3 by a timing belt 2 and guided by a guide member 4 so as to be parallel to a platen 5. It is configured to move. Recording paper 6 on carriage 1
A recording head 7 for color printing is provided on the surface opposite to, and the recording head 7 receives ink from the ink cartridge 8 and ejects ink droplets onto the recording paper 6 for printing.

A capping device 10 is connected to the pump unit 11 via a tube and has a size capable of sealing the nozzle opening surface of the recording head 7 in one space. The nozzle opening surface is sealed when not printing. Further, the ink is forcibly discharged from the recording head 7 by receiving a negative pressure from the pump unit 11 at the time of the stop operation and the discharge capacity recovery operation.

2 and 3 are a perspective view and an assembled perspective view showing an embodiment of the capping device of the present invention, respectively, in which reference numeral 12 is a slider, and the carriage 1 is moved to a non-printing area. Sometimes, it is configured to follow the movement of the carriage 1 and move the upper surface of the base 13 in the horizontal direction and the vertical direction.

A cap member 14 for sealing the nozzle opening surface of the recording head 7 is provided in one half of the upper surface on the printing area side (left side in the drawing), and the other half is an outer area (right side in the drawing). Is provided with a valve unit 15, and a flag piece 16 that comes into contact with the carriage 1 is provided at the outermost end.

The slider 12 has a protruding piece 1 at the lower end on the outermost end side.
7 has a guide surface 18 of the base 13 and slides on the surface thereof, and also has a protrusion 19 on the side of the printing area which is orthogonal to the moving direction of the carriage 1. An arm 2 whose one end is rotatably supported by the base 13 with a long groove 20a.
It is rotatably supported by the other end of 0, and the base 13 and the arm 2
The compression spring 21 inserted between 0 and 0 always urges the printing area side upward to take a substantially horizontal posture. The projection 19 that engages with the arm 20 is formed with a through hole 19a that communicates with an ink suction port 41 of a cap 40, which will be described later, and also serves as a connection flow path.

On the other hand, the guide surface 18 of the base 13 has a low point 18a and a high point 18b so that the cap member 14 can occupy a position apart from the nozzle plate and two positions in which the cap member 14 elastically contacts the nozzle plate. And a slope 18c connecting them, and a stopper 29 for determining a limit point is formed at the outermost end of the high place 18b.

As shown in FIG. 4, the cap member 14 is roughly divided into a cap 40 and a support frame 50 for holding the cap 40. The cap 40 is made of synthetic resin such as rubber having ink resistance, and is provided with an ink suction port 41 and an atmosphere communication port 42.

The ink suction port 41 and the atmosphere communication port 4
2 is a conduit 4 integrally formed with the cap 40.
3 and 44, valve unit 15 and suction pump 1
Connected to 1. These conduits 43 and 44 are provided at intervals in the moving direction of the carriage 1, and the conduit 44 on the non-printing area side is configured to be longer than the other conduit 43, and the elasticity of the conduit 44 causes the cap 40 to move. The print area side is configured to have a lower position.

First and second ink absorbing sheets 70 and 71 made of a porous material having ink resistance and ink absorbability are inserted into the cap 40 so as to cover substantially the bottom surface thereof, and the upper layer is formed. The second ink absorbing sheet 71 located is fixed by the protrusion 45 formed on the inner peripheral surface side of the cap 40.

The support frame 50 has a cap 40 on the bottom.
The conduits 43, 44 have holes 51, 51 penetrating therethrough, and a recess 52 formed at the center thereof is fitted into a protrusion 23 extending from the base 13 so that the conduit 52 can be separated from the slider 12 on one side. The protrusions 52, 52 on the side portions are pressed by the spring 24 interposed so as to be biased toward
It is inserted in 5 and is attached so that it can swing.

The valve unit 15 is urged toward the valve seat side by a valve seat 27 having an opening connected to the atmosphere communication port 42 of the cap 40 by a tube 26 and a spring 28 at all times.
A valve body 31 having an operating rod 30 that moves when the slider 12 contacts the stopper 16.
Is configured as a normally closed valve that separates the valve body 31 from the valve seat 27.

FIGS. 5A and 5B show an embodiment of the above-mentioned cap. The cap 80 has a plurality of protrusions whose lower surface is slightly lower than the upper surface of the ink absorbing sheet 90. The sheet 90 is configured to be pressed and stored on the bottom surface side by 81 and 82. Projections 81, 82
Are arranged substantially evenly on the inner peripheral surface 83 of the cap 80 in such a number that the floating of the ink absorbing sheet 90 can be prevented.

On the other hand, the ink absorbing sheet 90 rides on the slope formed on the inner peripheral surface 83 of the cap 80, and forms a tongue piece 91 that comes into contact with the ink held between the recording head and absorbs the ink. The cap 80 is housed in the cap 80 while being prevented from moving in the vertical direction in cooperation with the protrusions 81 and 82.

The projections 81 and 82 are arranged in a nozzle opening row N, N, N when the nozzle plate is sealed as shown in FIG.
... is formed at a position that does not face .., and the area thereof is selected to be smaller than the surface area of the tongue piece 91 of the ink absorbing sheet 90, and the amount of ink stagnant in the protrusions 81 and 82 can be controlled as much as possible. It is configured to suppress it.

In order to reduce the amount of ink stagnation as much as possible, the protrusions 81 and 82 have chamfered portions 81a and 82a formed at the corners of the tips as shown in FIG. 7, or as shown in FIG. As shown in FIG. 9, notches 81c and 82c are formed in the central portion as shown in FIG.
Are formed to reduce the surface area within a range that does not hinder the holding of the ink absorbing sheet 90.

As shown in FIG. 10, the protrusions 84 and 85 have a peripheral edge side length a smaller than a side length b protruding toward the ink absorbing sheet 90, and an aspect ratio. It is desirable to make it large. Further, as shown in FIG. 11, the length a of the side on the peripheral edge side is such that the amount c of rising ink adhering thereto is smaller than the distance e between the nozzle face of the recording head and the seal surface d. , C = √ [{8-a ² (1-cos θ)} / {4 (1-cos
θ)}] However, it is desirable to set θ to indicate a wetting angle.

When the aspect ratio is increased in this way,
Since the rigidity of the protrusions 84 decreases and the pressing force of the ink absorbing sheet decreases, as shown in FIG. 12, a large number of gaps f and f'are provided so that a capillary force is not generated between the protrusions 84, 84. Is desirable.

Further, the projection 84 is formed such that at least the tip end portion 84a thereof has such an elastic force that it is slightly filled with Δg in the ink absorbing sheet 90 as shown in FIG. 13A, and FIG. As shown in Fig. 13, the radius R of roundness of the tip end portion 84a can be made as small as possible, and
As shown in (c), when the tip portion 84a is formed to have an acute angle and the angle α of the slope is increased, the ink I accumulated on the convex piece 84 is moved to the ink absorbing sheet 90 side, and the ink absorbing sheet 90 is formed. Can be absorbed promptly.

Further proceeding, FIG. 14 (a), (b),
As shown in (c), the protrusion 85 is provided with the inclined surfaces 85a, 85a with the ink absorbing sheet side facing downward, so that the ink is absorbed not only from the protruding side but also from the periphery.
It is possible to prevent the ink from stagnation by flowing out to 0 as much as possible.

Further, as shown in FIG. 15 (a), the inner peripheral surface 83 of the cap 80 is formed to have a concave cross section, or as shown in FIG. 15 (b), the overhang portion 83a.
If a concave portion having a small radius of curvature is formed so as to be connected to the protrusion 84 with a smooth slope, the inner peripheral surface 8
It is possible to guide the ink in the ink 3 and the folds 80a to the ink absorbing sheet 90 using the protrusions 84.

Further, as shown in FIGS. 16 (a) and 16 (b), the relatively wide projections 81 and 82 described above are
A narrow groove 81 to the side of the fold where ink can be sucked by capillary force.
When d and 82d are formed parallel to the peripheral direction, the ink accumulated in the folds can be captured by the grooves 81d and 82d.

Further 17 (b), the narrow groove 81e extending perpendicular to the peripheral direction as shown in (b), to form a 82e, the ink adhered to the fold portion 80a narrow groove 81e,
The ink absorbing sheet 90 can be moved by 82e .

Further, as shown in FIG. 18, at least a region facing the protrusion 84 of the ink absorption sheet 90 is formed with a thin portion 92, and the thin portion 92 covers the protrusion 84. The ink can be moved to the ink absorbing sheet 90 without being stagnant in the area 84.

Further, as shown in FIG. 19A, an ink absorbing material is coated on the surface of the projection 84 to form an ink absorbing layer 85, or as shown in FIG. When the agent is applied to form the ink-philic layer 86,
It is possible to absorb the ink on the surface of the protrusion 84 or to move the ink to the ink absorbing sheet 90 promptly without increasing the apparent thickness of the protrusion in the thin portion of the ink sheet.

[0030]

As described above, according to the present invention ,
The stagnation of the ink in the projection an ink absorbing sheet pressing member small without also made low swelling volume as much as possible, the ink mist generated at the time of cap opening can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an embodiment of the capping device of the present invention.

FIG. 3 is an assembled perspective view of the same device.

FIG. 4 is a sectional view showing a structure of a cap member.

5 (a) and 5 (b) are a top view and a cross-sectional view showing an embodiment of the cap of the present invention.

FIG. 6 is a diagram showing a relationship between relative positions of nozzle openings and protrusions when the recording head is sealed by the same cap.

FIG. 7 is a top view showing another embodiment of the cap of the present invention.

FIG. 8 is a top view showing another embodiment of the cap of the present invention.

FIG. 9 is a top view showing another embodiment of the cap of the present invention.

FIG. 10 is a top view showing another embodiment of the cap of the present invention.

FIG. 11 is an explanatory diagram showing the relationship between the width of the protrusion of the cap and the height of the ink attached to the protrusion.

FIG. 12 is a top view showing another embodiment of the cap of the present invention.

13A to 13C are cross-sectional views showing another embodiment of the same cap, respectively.

14A to 14C are a top view and a cross-sectional view, respectively, showing another embodiment of the cap.

15 (a) and 15 (b) are cross-sectional views showing another embodiment of the cap.

16 (a) and 16 (b) are respectively a top view and a cross-sectional view of a cap.

17A and 17B are a top view and a cross-sectional view of a cap, respectively.

FIG. 18 is a cross-sectional view showing an example of an ink absorbing sheet.

19 (a) and 19 (b) are cross-sectional views showing another embodiment of the cap.

20A and 20B are cross-sectional views showing a state of the conventional cap immediately after ink suction and a state of ink when the cap is released.

[Explanation of symbols]

1 carriage 7 recording head 8 ink cartridges 10 Capping device 14 Cap member 40 cap 41 Ink suction port 42 Air communication port 80 cap 81, 82 protrusions 90 ink absorption sheet 91 tongue

Front page continued (72) Inventor Shigenori Fukasawa 3-3-5 Yamato, Suwa, Nagano Seiko Epson Corporation (72) Masahiro Nakamura 3-3-5 Yamato, Suwa, Nagano Seiko Epson Corporation In-company (72) Inventor Atsushi Kobayashi 3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (56) Bibliographic references Kaihei 5-35281 (JP, U) (58) Fields investigated (Int .Cl. ⁷ , DB name) B41J 2/165

Claims (8)

(57) [Claims] 1. An ink jet recording head for ejecting ink droplets from a nozzle opening in response to a drive signal, and a cap for holding the ink absorbing sheet by a protrusion formed on the inner peripheral surface and a tongue formed on the ink absorbing sheet. An ink jet recording apparatus comprising: a capping device including: a groove having a width capable of sucking ink by a capillary force. 2. A cap for holding the ink absorbing sheet by an ink jet recording head for ejecting ink droplets from a nozzle opening in response to a drive signal, a protrusion formed on an inner peripheral surface, and a tongue formed on the ink absorbing sheet. In the ink jet recording apparatus, the width a of the protrusion in the peripheral direction of the cap is smaller than the distance e from the seal surface d, e> √ [{8-a2 (1-cos θ)} / {4 (1-cos θ)}] (where, e represents the distance from the seal surface, and θ represents the wetting angle). . 3. The ink jet recording apparatus according to claim 1, wherein a chamfered portion is formed at a tip of the protrusion. 4. The ink jet recording apparatus according to claim 1, wherein a rounded portion is formed at a tip of the protrusion. 5. The ink jet recording apparatus according to claim 1, wherein a notch is formed at the center of the tip of the protrusion. 6. The ink jet recording apparatus according to claim 1, wherein an ink-philic layer is formed on an upper surface of the protrusion. 7. The ink jet recording apparatus according to claim 6, wherein the ink-philic layer is formed of the ink absorbing sheet. 8. The ink jet recording apparatus according to claim 1, wherein the inner peripheral surface of the cap is formed in a concave shape.