JPH07156416A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To prevent the clogging of the nozzle part of a recording head by a simple structure. CONSTITUTION:In an ink jet recording apparatus having a recording head 50 having a nozzle part 54, a cap 16 arranged so as to be capable of coming into contact with the recording head 50 to cover the periphery of the nozzle part and the suction pump connected to the cap, an ink humectant 55 is arranged to the surface of the recording head connected to the cap so as to surround the periphery of the nozzle part 54 to be brought into contact with the entire periphery of the cap and a part of the ink humectant is arranged in the cap so that the other part of the ink humectant is exposed to the atmosphere.

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 ejecting ink droplets from an ejection port of a recording head to print on a recording sheet, the ink jet recording apparatus having means for preventing clogging of a nozzle portion of the recording head. It is a thing.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, since a nozzle portion for ejecting ink is extremely fine, when the state of not recording continues, the viscosity of the ink increases due to evaporation of water from the nozzle portion and the ink dries. However, the nozzle may be clogged. In addition, paper dust, dust or the like may adhere to the nozzle portion, which may cause clogging of the nozzle portion, which may lead to defective recording without proper ink ejection.

Conventionally, in order to solve this problem, in JP-A-57-22064, JP-A-57-117966, etc., a cap made of an elastic body is provided in the nozzle portion so as to be capable of being press-contacted. An ink absorber is provided inside or on the cap surface, and ink vapor is filled around the nozzle portion to prevent the nozzle portion from drying. Further, in JP-A-57-22064, the cap is connected to a negative pressure generating means to suck ink in the nozzle portion to prevent clogging of the nozzle portion.

However, when the negative pressure generating means is connected to the cap, when the cap is pressed against the nozzle portion, the hollow portion of the cap of the elastic body is deformed, so that the volume inside the cap is reduced and the inside of the cap is temporarily changed. As a result, air or dust may enter the nozzle portion. In order to solve this problem, Japanese Patent Laid-Open No. Hei 3
In Japanese Patent Laid-Open No. 180354, there is provided a pump for generating a negative pressure in the cap to suck the ink in the nozzle portion, a flow path for communicating the inside of the cap with the atmosphere, and a valve for opening and closing the flow path. ing.

[0005]

However, in the method disclosed in Japanese Patent Laid-Open No. 3-180354, the mechanism and control for pressing the cap, driving the pump, and opening and closing the valve are complicated, and the cost is increased. Have the problem of doing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an ink jet recording apparatus capable of preventing clogging of a nozzle portion of a recording head with a simple structure. .

[0007]

To this end, an ink jet recording apparatus according to the present invention comprises a recording head having a nozzle portion, a cap disposed so as to be capable of contacting so as to cover the periphery of the nozzle portion, and the cap. In an inkjet recording apparatus having a connected suction pump, an ink moisturizing material is arranged on the surface of the recording head facing the cap so as to surround the nozzle portion, and the ink moisturizing material is brought into contact with the entire circumference of the cap, Part of the ink moisturizer is inside the cap,
It is characterized in that the other part of the ink moisturizing material is arranged so as to be exposed to the atmosphere.

Incidentally, blade means for cleaning the nozzle portion may be provided,
The nozzle portion may be made to project more than the ink moisturizing material, or the surface portion of the ink moisturizing material may be inclined. A rough surface may be formed on the surface of the ink moisturizing material, or the ink moisturizing material may be mounted in the recording head. Further, the ink moisturizing material may also serve as the recording head constituent portion, or a nozzle portion for ejecting a plurality of color inks may be formed in one recording head and each color nozzle portion may be surrounded by one ink holding material. You may make it arrange | position so that it may surround.

[0009]

In the present invention, in order to prevent the ink in the nozzle portion from being dried, an ink moisturizing material is provided in the peripheral portion of the ink ejection facing the cap covering the nozzle portion, and the moisturizing material is capped while the head is on standby. The nozzle part of the head is sealed via a moisturizing material to shut off the air from the atmosphere to keep the inside of the cap moisturized and prevent the ink of the nozzle part from drying, and at the same time, the cap pressure contact and the cap contents at the time of retreat The pressure fluctuation in the cap due to the minute change of the product is absorbed by the moisturizing material itself or communication with the atmosphere to reduce the pressure fluctuation.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of an inkjet recording apparatus to which the present invention is applied, and FIG. 2 is a sectional view of the vicinity of the maintenance unit shown in FIG. The present invention is not limited to such a multi-color recording device, but can be applied to a single-color recording device.

In FIG. 1, a carriage 2 is slidably mounted between two guide rails 1.
Are connected to a carriage driving motor 4 via a timing belt 3. Four inkjet cartridges 5 of cyan, magenta, yellow and black are mounted on the carriage 2. These ink cartridges are detachably attached to the carriage 2 by the lock lever 6. A recording head (50 in FIG. 2) having a large number of ink ejection nozzles is provided on the lower surface of each ink jet cartridge 5, and an ink tank 7 that supplies ink to the recording head is built-in. The drive signal is transmitted by the signal cable 8.

A feed roll 9 and an exit roll 10 are arranged between the two guide rails 1 in parallel with each other, and the feed roll 9 and the exit roll 1 are provided.
0 is connected to a paper feed motor 14 via gears 11, 12 and a belt 13. Recording on the recording paper 15
While moving the carriage 2 from the left to the right of the recording paper 15, the recording head is driven to perform recording for the head width, and the recording paper 15 is moved by the width of the head in the arrow direction in the figure in preparation for the next printing. There is. A cap 1 for covering the nozzle of the recording head is provided at a position facing the end of the guide rail 1.
A maintenance unit 17 having 6 is arranged so as to be able to move up and down.

FIG. 2 is a sectional view of the vicinity of the maintenance unit 17 of FIG. In the figure, two recording heads 50
Only the other recording heads are omitted. In FIG. 2, the maintenance unit 17 includes a housing 18 having an opening at the top in the drawing, and a rotary shaft 20 that is rotated by a cap moving motor 19 is disposed in the housing 18.

Eccentric cams 21 are fixed on both sides of the rotary shaft 20, and the eccentric cam 21 is formed with a circular groove 22 eccentric to the rotary shaft 20. Housing 18
A cap moving table 23 is arranged in the opening of the. A guide groove 24 is formed on both inner sides of the housing 18, and a projection 25 that fits into the guide groove 24 and a projection 26 that fits into the circular groove 22 are formed on the cap moving base 23.

A plate 27 is provided on the cap moving table 23.
The cap support member 28 is movably provided by the above, and is urged upward by a spring 29 in the drawing. The cap 16 is fixed to the upper portion of the cap support member 28. A suction passage 30 is formed from the bottom of the cap 16 to the inside of the cap support member 28.
Is connected to a suction pump 32 via a tube 31.

A casing 33 for supporting the feed roll 9 is arranged on one side of the maintenance unit 17, and a wiper blade 34 is fixed to the casing 33. The wiper blade 34 may be fixed to the maintenance unit 17 side.

Maintenance unit 1 having the above structure
The operation of No. 7 will be described. When not recording,
After the recording head 50 is stopped at a position facing the cap 16, the cap moving motor 19 is driven to drive the eccentric cam 2.
When 1 rotates, the protrusion 26 is pushed up by the circular groove 22, and the protrusion 25 moves upward along the guide groove 24 in the figure, so that the cap moving table 23 rises and the cap 16 moves the nozzle portion of the recording head 50. The nozzle is prevented from being dried and dust is adhered to the nozzle by pressing it to cover it, and unnecessary ink, dust, etc. adhering to the nozzle portion or bubbles in the recording head are sucked and removed by the suction pump 32. ing. When the recording head 50 moves to the feed roll 9 side to perform the recording operation, the recording head 50 finishes the recording operation and the maintenance unit 17
When moving to the side, unnecessary ink attached to the nozzle portion of the recording head 50 is cleaned by the wiper blade 34.

FIG. 3 shows an embodiment of the ink jet recording apparatus of the present invention. FIG. 3 (A) is an enlarged sectional view of a recording head and a cap, and FIG. 3 (B) is a line BB of FIG. 3 (A). FIG. 3C is a cross-sectional view seen along the arrow in the direction of the arrow, and FIG. 3C is a view for explaining the volume change due to the crush of the cap.

In FIGS. 3A and 3B, the recording head 50 includes a head body 51, a heat sink 52 provided in the head body 51, and an ink supply path provided in the vicinity of the heat sink 52. 53 and the ink supply path 53
The nozzle portion 54 is formed at the tip of the nozzle portion 54, and the ink moisturizing material 55 is provided so as to surround the periphery of the nozzle portion 54. The ink moisturizing material 55 is made of a porous material or a fibrous material and allows the ink moisturizing material 55 to come into contact with the entire circumference of the cap 16. Part of the ink moisturizing material 55 is inside the cap 16 and the ink moisturizing material is The other part of 55 is arranged to be exposed to the atmosphere. The surface of the ink moisturizing material 55 may be roughened, or the ink moisturizing material 5 may be formed.
Water may be included at the beginning of 5.

The operation will be described. When the recording head 50 reciprocates in the direction of arrow Z in FIG. 3A, unnecessary ink adhering to the nozzle portion 54 of the recording head 50 is wiped off by the wiper blade 34 and wiped. The taken ink permeates the ink moisturizing material 55. When the cap 16 is brought into pressure contact with the ink moisturizing material 55, the ink moisturizing material 55 is dispersed with the unsaturated water-containing ink 56, and the water content of the ink 56 flows into the cap 16 as shown by the arrow X, Nozzle part 5 when capped for a long time
4 prevents the ink from drying. In addition, inside the cap 16, the porous or fibrous cavity 5 of the ink moisturizing material 55 is provided.
Since it communicates with the atmosphere as shown by an arrow Y via 7 itself or the cavity 57, it is possible to absorb the air pressure fluctuation due to the cap chamber volume change in the cap state.

In FIG. 3C, the atmospheric pressure is P, the volume inside the cap 16 at the beginning of capping is V, the volume change due to the collapse of the cap 16 from the beginning to the end of capping is ΔV, and the volume of the cap 16 is If the pressure change from V to V-ΔV is Δp, the pressure fluctuation is Δp
= P · ΔV / V Note that this pressure fluctuation similarly occurs when the cap 16 is retracted, but since it communicates with the atmosphere through the hollow portion 57 itself or the hollow portion 57, the air pressure accompanying the change in the cap chamber volume in the cap state. Fluctuations can be absorbed.

4 to 9 are views showing another embodiment of the present invention. The same components as those in the embodiment of FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

In the embodiment of FIG. 4, the position of the nozzle portion 54 is projected from the ink moisturizing material 55. As a result, the unnecessary ink 58 attached to the nozzle portion 54 of the recording head 50 is easily wiped off by the wiper blade 34, and the wiped ink permeates the ink moisturizing material 55.

In the embodiment of FIG. 5, the ink moisturizing material 5 is used.
By forming the inclined surface 55a on the lower surface of 5, the cleaning property by the wiper blade 34 is improved.

In the embodiment of FIG. 6, the ink moisturizing material 5 is used.
5, a projection 55b is formed on the lower surface of the cap 5, and the projection 55b is fitted to the inner surface of the cap 16 to form the cap 16
The airtightness inside is improved.

In the embodiment of FIG. 7, the ink moisturizing material 5 is used.
5 is mounted in the head main body 51 to prevent the hands and the like from being stained with ink when the recording head 50 is attached and detached.

The embodiment of FIG. 8 is an embodiment in which the ink moisturizing material 55 is also used as the head main body 51, and the ink tank 6 is used.
0 and the ink moisturizing material 55 are combined, and the heat sink 52 and the ink supply path 53 are provided in the ink moisturizing material 55. According to the present embodiment, the surface area of the ink moisturizing material 55 is large and the moisturizing effect is increased, and the heat dissipation of the nozzle portion 54 is enhanced to prevent ejection failure due to heat storage, and the number of constituent parts can be reduced.

In the embodiment shown in FIG. 9, a recording head 50 for ejecting a plurality of color inks is provided as one head body 51.
The nozzle portion 54 of each color is arranged so as to surround the periphery with one ink moisturizing material 55.

[0029]

As is apparent from the above description, according to the present invention, the cap is brought into contact with the ink moisturizing material while the recording head is on standby, and the nozzle portion of the head is sealed via the ink moisturizing material. By shutting off from the atmosphere, the inside of the cap is moisturized to prevent the ink in the nozzle part from drying, and at the same time, the pressure fluctuation inside the cap due to a slight change in the internal volume of the cap when the cap is turned on or off is communicated with the ink moisturizer itself or the atmosphere. The pressure fluctuation can be reduced by absorbing, and the clogging of the nozzle portion of the recording head can be prevented with a simple structure. Further, the residual ink adhered to the wiper blade can be absorbed, and normal ink ejection can be obtained from the start of printing.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an inkjet recording apparatus to which the present invention is applied.

FIG. 2 is a cross-sectional view near the maintenance unit of FIG.

FIG. 3 shows an embodiment of an inkjet recording apparatus of the present invention, FIG. 3 (A) is an enlarged sectional view of a recording head and a cap, and FIG. 3 (B) is taken along line BB of FIG. 3 (A). And FIG. 3C is a diagram for explaining the volume change due to the crush of the cap.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the present invention.

FIG. 6 is a sectional view showing another embodiment of the present invention.

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

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

FIG. 9 is a cross-sectional view showing another embodiment of the present invention.

[Explanation of Codes] 16 ... Cap, 17 ... Maintenance Unit, 32 ...
Suction pump 34 ... Wiper blade, 50 ... Recording head, 51 ... Head body 53 ... Ink supply path, 54 ... Nozzle section, 55 ... Ink moisturizing material

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B41J 2/175 B41J 3/04 102 Z

Claims (9)

[Claims] 1. An ink jet recording apparatus comprising a recording head having a nozzle portion, a cap disposed so as to be capable of contacting so as to cover the periphery of the nozzle portion, and a suction pump connected to the cap, An ink moisturizing material is arranged on the surface of the recording head facing the cap so as to surround the nozzle portion, and the ink moisturizing material is brought into contact with the entire circumference of the cap. An ink jet recording apparatus, characterized in that the other part is disposed so as to be exposed to the atmosphere. 2. The ink jet recording apparatus according to claim 1, further comprising blade means capable of cleaning the nozzle portion. 3. The ink jet recording apparatus according to claim 1, wherein the nozzle portion is projected more than the ink moisturizing material. 4. The ink jet recording apparatus according to claim 1, wherein a surface portion of the ink moisturizing material has an inclination. 5. The ink jet recording apparatus according to claim 1, wherein a rough surface is formed on the surface of the ink moisturizing material. 6. The ink jet recording apparatus according to claim 1, wherein the ink moisturizing material is mounted in a recording head. 7. The ink jet recording apparatus according to claim 1, wherein the ink moisturizing material also serves as a recording head constituting section. 8. A nozzle part for ejecting a plurality of color inks is formed in one recording head, and each color nozzle part is arranged so as to be surrounded by one ink moisturizing material. The inkjet recording device according to claim 1. 9. The ink moisturizing material is arranged so as to be in contact with the tip portion of the blade means when the nozzle portion of the recording head is cleaned by the blade means. The ink jet recording apparatus according to any one of claims.