JPS60141564A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To prevent a meniscus from retracting when a cap is fitted, by a method wherein the tip of a communicating pipe for communicating the interior of a tank substantially to the atmosphere is located in proximity to a projected end of an ink jet nozzle, and the tip end and the projected end are sealed by a cap in the condition of being communicated to each other. CONSTITUTION:Where a recording head 11 is located at a home position, when the cap 21 is pressed in the direction of an arrow D, a packing member 22 is brought into contact with a recording surface 16a of a carrier body 16, and further pressing causes an elastic deformation, thereby raising the pressure. In this case, since the tip of the ink jet nozzle 18 and the tip of the communicating pipe 20 are communicated with each other, the pressure is substantially absorbed into an upper space 24 in the interior of a sub ink tank 17. Accordingly, the meniscus in the nozzle 18 is prevented from retracting, the problem of air being forced into the nozzle to make it impossible to jet ink droplets or the like can be prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an inkjet recording device equipped with a cap that seals the tip of a nozzle.

(Prior art) Usually, water-soluble dye is used in the ink of an inkjet recording device, and the main solvent for dissolving and dispersing it is water. Therefore, water, which is the main solvent of the ink, evaporates from the nozzle. When the viscosity of the ink on the nozzle surface increases, it may become impossible to eject ink droplets. In order to prevent this kind of phenomenon, in the home position of the recording device, the stand-by Niall head is covered tightly with a cap to maintain a highly humid atmosphere inside and to prevent ink from evaporating from the nozzles. There is a mechanism in place to reduce this amount.

FIG. 1 shows a conventional ink evaporation prevention mechanism, in which a cap 1 is pressed against a recording head 2 to isolate nozzles 6 from the outside air. Here, the packing material 4 made of an elastic body attached to the tip of the cap 1 contracts and deforms when the cap 1 is pressed in the entry direction, which is the direction toward the head 2, and the pressure inside the cap 1 increases. As a result, the meniscus 6 of the ink 5 at the tip of the nozzle 3 is pushed back into the inside of the nozzle, and as a result, air is forced into the nozzle 6. The object of the present invention is to eliminate the above-mentioned drawbacks, and to provide an inkjet recording apparatus that does not cause the meniscus in the nozzle to retreat during capping.

(Embodiment) FIG. 2 shows an inkjet recording apparatus according to an embodiment of the present invention, in which a timing belt 8.
The recording head 11 is reciprocated in both the left and right directions, that is, in the B and C directions, directly along the two guide shafts 10 via the googly 9.

A recording sheet 1 is placed on the platen 12 in front of the recording head 11.
6 is set 0 Also, at the left end position in the figure, which is the home position of the recording head 11, there is a cap mechanism 1 that is an ink evaporation prevention mechanism.
4 is placed.

FIG. 6 shows a cross section taken along the line ■--■ in FIG. Recording head 11
As shown in the figure, a sub-ink tank 17 is integrally fixed to a carrier body 16 which integrally has a bearing part 15 that fits into the shaft 10, and an inkjet nozzle 18 with one end immersed in the sub-ink tank 17 is attached. The inkjet nozzle/I/18 has a configuration embedded in the carrier body 16, and the tip ejection portion of the inkjet nozzle/I/18 projects onto the recording plane 16a of the carrier body 16.

Further, the sub ink tank 17 is connected to the flexible tube 1
It is connected to a main ink tank (not shown) via an inkjet nozzle 18, and as ink is ejected from the inkjet nozzle 18, ink is replenished from the main ink tank. Furthermore, an atmosphere communication pipe 20 is embedded in the carrier body 16 at a position above and close to the inkjet nozzle 18 to keep the inside of the ink tank 17 substantially in communication with the atmosphere at all times. The atmosphere communication tube 20 has one end protruding into the sub-ink tank and the other end facing the recording plane 16a of the carrier body 16. In this way, the tips of the inkjet nozzle 18 and the atmosphere communication tube 20 protrude closely from the recording plane 16a of the carrier body 16. Atmospheric communication pipe 2
The inner diameter of the inkjet nozzle/L18 is set to be twice or more the diameter of the ejection orifice of the inkjet nozzle/L18. Further, when the cross section of the atmosphere communication pipe is not cylindrical but rectangular, the maximum side length thereof should be at least twice the orifice diameter.

When the recording head 11 comes to the home position, the cap 21 of the cap mechanism 14 is projected by a solenoid (not shown) in a direction approaching the recording head 11, that is, in the direction D.
A packing material 22 fixed to the tip of the cap 21 suppresses the recording surface 16a'i: of the carrier body 16, the inkjet nozzle 18, and the atmosphere communication pipe 20 so as to block them from the outside. As a result, the tip of the inkjet nozzle 18 and the tip of the atmosphere communication tube 20 are sealed.

Further, a sponge-like ink absorber 26 is fixed to the inner surface of the gap 21, and the ink absorber 26 is fixed to the inside of the cap.
The evaporation of the ink from the nozzle 18 can be kept to a minimum by keeping it moist. The ink absorber 26 is replenished with ink by performing a trial ejection of ink at the home position.

Now, when the recording head 11 is at the home position, when the cap 21 is released in the D direction, the packing material 22 first comes into contact with the recording plane 16a of the carrier body 16. Further compression thereafter compresses and deforms the packing material 22, and the pressure inside the cap 21 increases by this amount. However, since the tip of the inkjet nozzle/I/18 and the tip of the atmosphere communication tube 20 are in communication with each other, this pressure that should be increased is almost absorbed by the upper space 24 in the sub-ink tank through the atmosphere communication tube 20. Ru. Strictly speaking, the inside of the nozzle 18 is filled with ink, and the viscosity, surface tension, etc. of the ink work to resist the receding of the meniscus. Also, the atmosphere communication pipe 20
Although ink may exist partially or completely in the nozzle 18, the meniscus of the nozzle 18 does not recede because its inner diameter is larger than the nozzle.

Further, the ink in the tank 17 is pushed by the amount that the upper space 24 in the sub-ink tank 17 is pressurized, creating a force that moves the meniscus toward the tip of the inkjet nozzle 18. In any case, as described above, the meniscus in the inkjet nozzle does not recede when there is a medium cast, which is preferable.

It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, the number of inkjet nozzles and atmospheric communication pipes may be any number. Furthermore, the capping mechanism referred to in the present invention does not merely seal the tip of the inkjet nozzle; The present invention can be applied to any device that caps the tip of the inkjet nozzle, including those having a function of suctioning the tip of the nozzle for the purpose of restoring the meniscus of the inkjet nozzle.

(Effects) As explained above, the present invention provides a system in which the tip of the communication tube that constantly communicates the inside of the tank with the atmosphere is provided close to the protruding end of the inkjet nozzle, and the nozzle discharge end and the tip of the communication tube are connected to each other. Since the cap is used to seal the inkjet nozzle in a communicating state, the meniscus of the inkjet nozzle does not retreat due to the pressure generated when the cap is applied.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view of a conventional ink evaporation prevention mechanism;
The figure is a plan view showing an example of an inkjet recording apparatus to which the present invention is applied, and FIG. 6 is a sectional view taken along the line ■--■ in FIG. 11... Recording head 14#... Cap mechanism 17
Lu-esub ink tank 18-Q Inkjet nozzle 20...Atmospheric communication tube 21...Cap applicant Canon Co., Ltd.

Claims (1)

[Claims] (1) A recording head having a nozzle for ejecting ink supplied from a tank, and a communication pipe that communicates the inside of the tank with substantially the atmosphere and has its tip disposed close to the ejection end of the nozzle. An inkjet recording device characterized by having a cap that seals the discharge end and the tip of the communication tube in a state where they are in communication with each other. (21) The inkjet recording apparatus according to claim 1, wherein the diameter or maximum side length of the passage tube is at least twice the diameter of the nozzle.