JPS6090763A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To stabilize and smoothen the movement of a cap for preventing blocking by a method in which a means of controlling the movement of the cap by air pressure is provided, and the center axis of the movement of the cap is almost equalized with the acting axis of air. CONSTITUTION:A bellows 19 of a double (inner and outer) structure is fixed by a bellows receiver 20. The bellows receiver 20 and a humidifier body 4 are fixed at the position where the humidifier body 4 passes the center of the bellows 19. Under the condition, when air pressure (a) is applied to the inside of the bellows 19 through an air supply pipe 15 from outside, since force to move the humidifier body 4 is uniformly acted on the surrounding of the humidifier body 4, moment centered on the body 4 is offset, the body 4 straightly moves in the axial direction and its back and forth actions are smoothened. The force required for movement can thus be lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inkjet recording apparatus that records characters and figures by flying droplets.

Conventional Structure and Problems One of the major problems with inkjet recording apparatuses is clogging of the inkjet head. This is because the diameter of the nozzle that ejects the ink is extremely small, around 60 μm, so if it is kept in a dry state for a long time, the dyes and additives in the ink will precipitate as crystals near the noise, causing the nozzle to dry. This is due to the blockage of the inkjet head, making it impossible to eject ink even if a signal is applied to the inkjet head next time. The nozzle may also be blocked by dust in the air. Measures to prevent nozzle clogging include sealing the nozzle with an elastic material such as rubber, or covering the area around the nozzle with a cap to maintain a high humidity inside. In any case, since the above state must be maintained when not recording, a different operating mechanism is required than when recording. Below, a conventional inkjet recording device will be explained with reference to the drawings. . Figure 1 (!L) and (b) are
FIG. 1 is a side view and a plan view of a conventional inkjet recording device. In the figure, the rotation of a motor 1 is reduced by a reduction gear 2 and transmitted to a cam 3. The rotational movement of the cam 3 is converted into a linear reciprocating movement of the humidifier body 4 and the cap 6. The disk 7 controls the non-recording state in which the nozzle area of the inkjet head 6 is covered with the cap 6 and the recording state in which the nozzle 3 surface and the camp 6 are separated.
This is done by detecting the perforation 8 provided in the 7-bit interrupter 9. A humidifying water container 1 is provided inside the humidifier body 4.
The humidifying water 11 in the glass fiber 1 in the humidifying water supply pipe 13
2 to keep the inside of the cap 5 in a high humidity state.

16 is a spring. The reason why the speed reduction gear 2 is used to reduce the speed of the linear motion of the cap 5 is as follows. In other words, if the cap 5 is momentarily pressed against the nozzle surface at a high speed to seal it, the pressure inside the cap 6 will rise rapidly, and there is a risk that air will enter the pressure chamber inside the inkjet head 6 from the nozzle in the form of bubbles. . If air is mixed into the pressure chamber, the pressure will not be sufficiently propagated, leading to phenomena such as unstable ink ejection or ink ejection failure. Conversely, if the camp 5 is suddenly removed from the nozzle surface, the pressure inside the cap momentarily becomes negative and ink is sucked out from the nozzle.
The reaction may cause air to be sucked into the pressure chamber of the inkjet head 6.

The operating mechanism of the clogging prevention device shown in Fig. 1 requires a motor 1 and a reduction gear 2 in order to linearly move the cap 5 at low speed, and the mechanism itself is complex, and the clogging prevention device covers the entire recording device. This accounted for a large proportion of the cost. Furthermore, since control during recording and non-recording is performed electrically, a circuit for this is also required.

Therefore, we simplified the operating mechanism of the clogging prevention device.

An inkjet recording device that is smaller and further reduces costs has been devised.

Examples thereof will be described below with reference to the drawings. Second
The figure is a side view of another conventional inkjet recording apparatus. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals. During non-recording (power off state), the nozzle surface of the inkjet head 6 is sealed by the cap 6, as shown in FIG. At the same time when the power is turned on and an air stream starts blowing out from the nozzle, air pressure from the same air source pushes the bellows 14 through the air supply pipe 15, pushing the humidifier body 4 backwards, and the spring 16 is pulled, causing the nozzle face and cap to be pushed back. 6 is released to enter the recordable state (REAI) (Y state 6 purge state). Since air pressure is always applied during recording, this state is maintained.

When the power is turned off, the air pressure drops to atmospheric pressure, and the camp 6 is pushed forward by the shibane 16, and the nozzle surface is sealed with the cap 6. The biggest feature of using air pressure is
Since the bellows 14 acts as an air damper, it takes time for the air pressure to rise and fall when the power is turned on and off, and therefore the speed of the back and forth movement of the cap 5 becomes slow. Since the air pressure supplied to the bellows 14 is the same as that supplied to the inkjet head 6, the force pushing the cap 6 backward is
determined by the cross-sectional area of

o, o In an inkjet head that requires an air pressure of about 1 kg/cd, the cross-sectional area of the bellows 14 is 3 to 6 cm, and a force of 300 to 500 g is obtained, which is sufficient and is also compact in terms of space. In addition, one of the features that uses air pressure is that the cap 5 when recording and when not recording.
Electrical control such as position detection is completely unnecessary.

Page 6 Please note that in Figure 3, the piston 17 is used instead of the bellows in Figure 2.
This is an example using a cylinder 18, and there is no difference in operation from that shown in FIG.

In Figure 3, the humidifying water container 10 and the humidifier main body 4 are combined to make the humidifier more compact, and at the same time, the influence of the humidifying water supply pipe 13, which is the cause of the unstable back-and-forth movement of the humidifier main body 4, is removed. It is something.

However, in the above configuration, the bellows 14. Screw! Since the /17O force acts as a moment, a large force is required to press the bellows 14-degree piston 17, resulting in a problem that the back and forth movement of the humidifier body 4 is not smooth.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks, the present invention provides an inkjet recording apparatus in which the clogging prevention device can be made more stable and smooth.

Structure of the Invention In order to achieve the above object, an inkjet recording apparatus of the present invention comprises: an inkjet head having a nozzle for ejecting ink, and a movable cap covering a nozzle surface of the inkjet head. , a control means for controlling the movement of the cap using pneumatic pressure, and a central axis of movement of the camp is substantially the same as an axis on which the pneumatic pressure acts.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 4 is a side view of an inkjet recording apparatus in one embodiment of the present invention. Components that are the same as those in FIG. 1 are designated by the same reference numerals and their explanations will be omitted.

In the figure, the bellows 19 has a double structure, inside and outside, and is fixed with a bellows receiver 2o. Bellows receiver 2
0 and the humidifier body 4 are fixed at a position where the humidifier body 4 passes through the center of the bellows 19.

In this state, the bellows 1 is passed through the air supply pipe 16 from the outside.
When air pressure is applied inside 9, the force that moves the humidifier body 4 acts uniformly around the humidifier body 4, so the moment centered on the humidifier body 4 is canceled out, and the humidifier body 4 moves in its axial direction. Since it moves straight and the back and forth movement is smooth, the force required for movement is much smaller.

Note that FIG. 6 shows another embodiment.

This uses a piston 20 (also used as the humidifier body 4) and a cylinder 21 instead of the bellows 19 shown in FIG. 4, and the operation 1 is the same as the embodiment shown in FIG. Omitted.

In this embodiment, a case has been described in which the cap 6 is moved in a direction perpendicular to the surface of the inkjet head 6, but the cap 6 is moved in the direction perpendicular to the surface of the inkjet head 6 by applying air pressure and the force of the spring 160 in the lateral direction of the cap.
It can also be moved parallel to the plane of the nozzle.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) Movement of the anti-clogging cap becomes stable and smooth.

(2) The configuration is simplified and compact.

[Brief explanation of the drawing]

Figure 1 (al is a 9-page side view of a conventional inkjet recording device, the same figure (bl is the same top view, Figure 2 is the same side view, 3
4 is a side view of an inkjet recording apparatus according to one embodiment of the present invention, and FIG. 6 is a side view of another embodiment of the present invention. 4... Humidifier body, 5... Cap,
6... Ink sheet spatula)', 19...
...Bellows, 20...Pisto/, 21...
···Cylinder. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] It has an inkjet head having a nozzle for ejecting ink, a movable cap that covers the nozzle surface of the inkjet head, and a control means that controls movement of the cap using pneumatic pressure, the central axis of movement of the cap being An inkjet recording apparatus characterized in that the axis on which the air pressure acts is approximately the same in tl.