JPS59131464A - Clogging preventing apparatus - Google Patents

Abstract

PURPOSE:To prevent air bubbles from being taken into a nozzle by eliminating a recessed meniscus and uniformly wetting a lid with ink, by applying the lid to the nozzle while the ink is slightly flowed out from the nozzle. CONSTITUTION:When the operation of a printing apparatus is stopped, a knob 17 is rotated to a predetermined direction. A cleaner 21 is rotated in synchronous relation to a cam to clean a nozzle 2 and a nozzle lid 24. When the rotation angle A2 of the knob 17 is 160 deg., the nozzle 2 is opened and a vent orifice 12 is closed. When the knob 17 is further rotated, a pump 11 made of butyl rubber is pushed to pressurize the ink 8 in a container 7 and the ink 8 is slightly flowed out from the nozzle 2 through a supply passage 4 and a pressure chamber 3. The nozzle 2 is closed in the knob rotation angle A3 by the nozzle lid 24 while the pump 11 is succeedingly pressurized for several 10ms - several 100ms and, thereafter, the pump lever 26 is retracted. In this state, the ink 8 in a head 100 and the ink container 7 is not flowed out and evaporation thereof is also suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink-on-demand type inkjet device 19, and more particularly to a cover means for preventing nozzle clogging.

The ink-on-demand type inkjet has the disadvantage that if air bubbles enter the head, the ink cannot be ejected. Another problem is that the evaporation of ink causes nozzle clogging. To prevent nozzle clogging, the nozzle is usually covered with a lid to prevent ink from evaporating to the outside. Put a lid on the nozzle at the same time
The problem with the single-shot head was that air bubbles formed inside the head, which was a problem due to the loss of sales of the Ministry of the Invention issue. As shown in FIG. 1, the reason for this is that the meniscus 1 of the nozzle 101
Because of 02, when the lid 103 is removed, air bubbles may be trapped in the nozzle, and when the lid 103 touches the nozzle 101, it may be unevenly wetted with ink and air bubbles may be trapped inside the nozzle. It will be done.

Therefore, the clogging of the present invention is to provide a clogging prevention means that prevents air bubbles from getting into the nozzle.

The gist of the present invention is that by closing the lid while allowing the ink to slowly flow out of the nozzle, a concave meniscus is formed, and the lid is evenly wetted with ink without introducing air bubbles into the nozzle. Figure 2 fJ2 is a schematic diagram of the entire bore of the instant embodiment of the present invention, which is a plan view of the device 7 seen from above.

1 is a polysulfon substrate with a nozzle 2 and a pressure chamber 3 around the surface.
, the supply channel A is shaped as a groove.

A head 10'0 is constituted by a polysal 7-on-note diaphragm stacked on the substrate 1 and a piezoelectric element 6 on the next surface. , 7 is an ink container made of polysulfon and having a diameter of about 10 m1, which is in contact with the substrate 1 and contains ink 8 inside. 9 is a vent hole with a diameter of 0.8 m provided above the ink container 7, and 10 is a pump hole with diameters o and am provided in line with the vent hole 9. Although the diameter of the ventilation hole 9 is large, there is insufficient ventilation when wet with ink.The reason why the pump hole is small is to prevent ink from evaporating.Butyl rubber with low vapor permeability is used for 11. The pump has a hemispherical shape with a radius of 5 mm, and an air vent 13 is placed in a part of the pump 12 with a vent lid integrally molded with the pump 11. The pump 11, the vent cover 12, and the ink container 7 are fixed to the ink container 7 with a holding frame 14 made of polysulfon, and the substrate 1, the shaker 5, the ink container ar7, and the holding frame 14 are bonded with solvent cement. . The ink yar integrated with the above head is mounted on a carriage that is not visible in the figure, and moves left and right along the guide shaft 15. 16 is a camshaft, and a knob 17 is mounted.

Knob 17, cam 1B, 19.20 and cleaner 21
is attached and rotates integrally with the knob 17. 22 is a coil spring, one end of which is attached to the knob 17 and is tightened to the cam I-16 to form a spring clutch so that the knob 17 can only rotate in one direction; 23 is a lid lever; 24
Silicone rubber nozzle lid attached to the lid lever 23, 25Hfl pore lever, 26rI pump lever
− is.

Lid lever 25, AM hole lever 25, pump lever 26
As the knob 17 rotates, the cam 1B, 19.degree. 20 moves to open and close the lid and drive the pump. In addition, in Fig. 2, the lid lever 26, the vent lever 25, and the main lever 2 are shown.
The springs that press against the 6τ cam are drawn by the Ministry of Economy, Trade and Industry.

27 is a magnet embedded in the knob 17, and 28 is a DIJ-de switch that detects the rotational position of the knob 17.

A platen 29 is arranged to the right of the lid and the cleaning means. The operation of the above-mentioned configuration in which the leg rest 931 partially protrudes from the frame of the 30i printing device will be explained with reference to the cam diagram in FIG.

During a normal printing operation, the recording head reciprocates left and right at a position facing the platen 29, which is partially shown in FIG. 2, and ink is ejected onto the recording paper set on the platen 29 (not shown). It is done by At this time, the angle of the camshaft is at the position A, = Oo, t shown in FIG. 3A.

The movement of the lid lever 23 @2 indicates N O (nozzle c
ap), the nozzle cover 24 is attached to nozzle 2 or 14.
11. The levers below move better than the purple head.

Similarly, the ventilation hole lever 25 is oriented away from the ink container (vent cap). In addition, the pump lever 26 is also separated from the pump 11 as shown by P (pump) VC, ° and the cleaner 21 is (cle
anθr), it is spaced above the nozzle cover 24. Shape of naori rete 21 and nozzle cover 24,
Regarding the positional relationship with the nozzle 2, it is turned on as shown in 2. Reed switch 2814 RS (reed switch), which will be described later.

When 2 seconds have passed since there is no more information to be printed in the side-turning circuit (not shown), the lf! , if the applied current of the VR-DC motor helps, the head 100. The ink container 7 stops at the desired stop position. If the user wants to stop the operation of the printing device, turn knob 17i VC, L! 121 turns.

In synchronization with the rotation of the cam, the cleaner 21 rotates as shown in FIG. 3C to clean the nozzle 2 and nozzle cover 24t. This situation is shown in the kmA diagram. When the knob 17 is rotated, the cleaner 21 also rotates at the same time.
An S dO plate blade 51 is bath-bonded, and a wiper blade 52 made of butyl rubber is attached to the tip thereof and is connected to IRF.

As the knob 17 rotates, the temporary spring 51 wipes the surface of the nozzle lid 26, and the wiper blade
52 wipes off the front surface r of the nozzle 2. While the cleaner 21 is wiping the two trays of nozzles, move the vent lever 25 to #J as shown in FIG. 3VC and press the vent cover 12τ against the vent hole 9 to close it.

In the knob rotation IJ (A, = 160', the nozzle 2 is enclosed and the ventilation hole 12 is closed. In this state, purging described below is possible. When the knob 17 is further rotated, the pump 11 is pressed. At the same time, the nozzle cover 24 approaches the nozzle 2. Therefore, the ink 8 in the ink container 7 yen
Apply pressure to the supply channel, valve the pressure chamber 3, and open the two nozzles)
A slight amount of oil oozes into ink 8. The capacity of the pump 11 is designed to increase the ink trough pressure f 1 to 10 tv H2O (about I U OPa to I Kpa), for example, 2 (7) ft H2O (about 200 Pa).
When , the ink 8 flows out from the nozzle 2 by 0.01 m.
The nozzle lid 24 closes the nozzle 2 while continuously pressurizing the pump 11tα1001s to several 100 mθ, which is enough to swell the ink 8 in front of the nozzle.
The dust pump lever 26 is retracted.

The state in which the nozzle cover 2Af is applied to the nozzle 2 at the knob rotation angle [A3 is taken first. In this state, the nozzle cover 24 and the vent cover 12 are closed, so that the ink in the head 100 and the ink container 7 yen does not flow out to the outside and evaporation is suppressed. The printing device is stored and transferred in this state. When restarting operation, turn the knob 17 seven times to open the vent cover, make the air pressure in the ink container the same as the outside air, and then open the nozzle. 24 opens. knob turns lj
At degree As, the reed switch 2B is turned on, and the control signal that is not turned on indicates that the pump is ready for operation.In addition, when the pump lever movement @P moves backward with the knob cAl and A3 shown in the figure, move forward. There is a sudden change, but this is not directly related to pump operation, but is due to the IP of the knob! In order to give a click feeling to the first rotation and to stabilize the knob at the stop position, the presser foot is prevented from breaking due to force and pressure.The details of the valley lever, cam, etc. of the embodiment shown in Fig. 42 are as follows.
Explain Ill.

In the A4 drawing, 7 talepas and 26 pieces are shown by two-dot chain lines. The lid lever 23 rotates at a lever @ 53 (! - 15%), and a convex silicone rubber nozzle lid 24 is attached to the tip as shown in the figure.The pin 54 of the lid lever 23 and the printing device Part 55 of the frame is pulled at both ends I!I:tt
The spring 56 is set, and the lid lever 23t is moved to the lid 2.
Cam 20 is pressed with the same sword as 4, and is partially upturned.
By doing so, the futa lever is placed in the 26-7 position.

Figure 5 shows the pump lever 26ky*T. pom lever 26
The lever 62 is engaged with the pin 61 provided in the vent lever 25 and the pin 63 provided in the vent lever 25, and the pump lever 26'f,
The same pressure is applied to the cam 18.

The cam 18 causes the pump lever 26 to push the pump 11 tray.

The pump hole 10 is provided at the bottom of the pump 11, and
It is easy to return the ink τ accumulated to 1 yen into the ink container 7.

The ventilation hole lever 25 is shown in the sixth part, and the ventilation hole cover 12'f5 is fixed by the same lever 62 VC as the sea urchin lever 26 mentioned above. In addition, the ventilation hole lever 2
The ink conduit 65 moves integrally with the nozzle 2 of the head 100 and comes into contact with and separates from the sponge-like outflow ink sensing member 65 provided at the bottom 1 of the ventilation hole 9. The lower end of the ink cartridge is retarded by the discharge ink cartridge 66 containing the absorbing member. The ink 8 flows out from the nozzle 2 and the vent hole 9 and is finally discharged from the ink cartridge 66il'ci! The purging at the rotation angle A2 in FIG. 3 will be explained below, depending on your convenience. Purging is performed when a bubble is generated in the pressure chamber 1@3Vc or when the nozzle 2 is clogged and ink cannot be ejected. Knob rotation angle + JjA.

When ink cannot be ejected, the user inserts the ink cartridge 71t shown in FIG.
Rotate the Shun knob 177 rotation angle FA2, and further push down the piston 73'7.

At this time, since the vent hole 9 is closed, the pressure inside the ink container 7 is still high, and the ink 8 flows out from the nozzle 2, clogging it and removing air bubbles. Note that the tip 74 of the cylindrical part of the ink cartridge 71 is exposed to pressure rise in the ink trough when pressure is applied.
What does a seal do to prevent ink from leaking between the tr75 and the rubber lid 76? 77 is a filter, 78 is an ink detection terminal, 79 is a kettle, etc., 80
81 is a flexible h tai, 81 V'X head cover, and ink container 8 is injected with dandruff at the time of A.
This is to reduce the tk of the air 82 inside to make the pressure at the time of purging easier. In addition, there is a ventilation hole 9 for replenishing ink when normal ink consumption occurs.

This is done with A open.

As explained above in the explanation of the IM example, according to the present invention, air bubbles enter the nozzle due to non-uniform wetting of the meniscus and the lid, since the lid is attached to the nozzle while allowing indandruff to flow out from the nozzle. There will be no uptake.

In particular, according to the above embodiment, since the pump pressure is several cm H20, the ink outflow amount can be kept to almost 0 in one stroke, and the intake of air bubbles can be suppressed, so that there is no wasteful consumption of ink.

In addition, since the nozzle lid has a convex tray m/recon rubber, the incorporation of air bubbles due to uneven wetting can be suppressed.

Reed % woodcutter bar's #] @τ - It's done with a cam that rotates 10,000 times, so it looks like an extreme lever! νξ It can be set easily and the nozzle lid will not flutter around the nozzle MiJ and air bubbles will not enter. Furthermore, the lid and nozzle are cleaned at the same time by a cleaning member that rotates in synchronization with the cam.
There is no possibility of ink leakage or ink evaporation due to the presence of dust between the nozzle and the lid, and the number of parts can be reduced.

The nozzle cover, vent cover, etc. are removed from the housing, and a signal output stage is installed that detects the IJ printing operation by the angle of the knob. On the other hand, it does not print for a long time 1-1.
When the lid is open, it is possible to monitor for a predetermined period of time and issue a warning signal indicating that printing is not being performed and a signal indicating that the lid is open.

Also, the nozzle lid and the ventilation 10L lid? By adjusting the selection time, it is easy to set the conditions that are lost during printing operation, ink injection, purging, storage, etc. Also, after releasing the air hole, the nozzle 7 can be used to release the ink pressure. Outside air and concave V
7) Ink ejection will not become impossible due to pressure changes in the ink trough due to changes in environmental temperature during maintenance.

In addition, the fl air hole cover and the pump T ink trough side are arranged in a dense layer, and a lever is used to push the air hole 7 and the pump, so external dust may accumulate on the air hole and pump hole. τF does not become unstable.

The ink conduit that moves in synchronization with the vent cover is the nozzle at '1.
By letting the ink flowing out from the vent hole flow into the discharge ink cartridge, the inside of the device will not be contaminated with flowing ink.

In addition, to position the nozzle, vent cover, and corresponding lever, a motor is used to forcibly press it against the carriage stem.
It has the advantage that it does not require fI11 and can be used for four degrees.

In addition, in the above embodiment, the operation of closing the lid while flushing out the dandruff with the cam is performed, but in addition, the operation of closing the lid is also carried out.
The pressure in a) applies pressure to the ink inside the head, and that pressure forces the V-shaped lid to fully open, causing air bubbles to form from the gap between the lid and the nozzle surface. It can also be flowed out together with the ink. In this case, the cost of rl'l'j1 for one-sided ink is high, but the sequence is simple, so from a conservative point of view, it is M profit.

'Furthermore, although a rubber diaphragm pump is used in the above embodiment 91, a piston-type pump or a pump for each pump that pressurizes the ink by gravity may be used.

The present invention can be used not only for ink-on-demand type inkjet using piezoelectric elements but also for printers using heat generating elements.In addition to serial printers, it can also be widely applied to line printers, facsimiles, copiers, block printers, etc.

[Brief explanation of the drawing]

Fig. 1 is a schematic view of the nozzle attachment points of the inkjet head, Fig. 2 is a plan view of an embodiment of the present invention, and Fig. 5 is a cam of the embodiment of Fig. 2. Figure 4 is a diagram showing the cleaner and nozzle lid of the embodiment shown in Figure 2, Figures 5 and 6 are diagrams showing the pump lever and vent hole number of the embodiment shown in Figure 2, and Figure 7 is 3 is a diagram illustrating a purging situation in the embodiment of FIG. 2; FIG. 2... Nozzle 100... Head 7... Ink container 8... Ink 9... Vent hole 10... Pump hole 11... Pump 12... Vent hole cover 17
... Knob 18.19.20 ... Cam 21 ... Cleaner 26 ... Lid lever 24 ... Nozzle lid 25 ... Vent lever 26 ... Pump lever
28... Reed switch 64... Ink conduit 6
6...Discharged ink cartridge 71...Ink cartridge and above Appearance: Epson Corporation Representative Patent Attorney Mogami Tsutomu Figure 100 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) An ink-on-demand type head, an ink-on-demand type head, a pump means for pressurizing the ink in the head, a pump drive means for continuously driving the pop means for seven hours, and a pump drive means for driving the pump means by the pump drive means. ? (2) an ink-on-demand head formed with a nozzle, a pressure chamber, etc., and an ink-on-demand head formed integrally with the head; For ventilation holes and pump holes! A first ink container disposed coaxially with an ink container, an elastic vent cover that covers the vent hole, an elastic pump that covers the front self-pump hole, and a first pump disposed on the same axis. second and fifth cams; a pump lever driven by the first cam to press the pump; and a vent lever driven by the second cam to push out the air hole lid. , the elastic nozzle ivy is driven by the cam to close the nozzle 2? a lid lever having a diameter of 11", and a cleaner and a sword disposed coaxially with the shaft and arranged between the nozzle and the elastic nozzle lid at selected times.
9 Preventing clogging of inkjet printers with the following characteristics: