JPS6290251A - Method for washing ink jet printer - Google Patents

Abstract

PURPOSE:To make it possible to certainly remove the inks in the peripheries of first and second orifices by enabling the washing of a pneumatic chamber with a washing solution, by providing a valve mechanism controlling the washing solution to an air supply pipe and feeding the introduced washing solution to the pneumatic chamber under pressure through said valve mechanism. CONSTITUTION:A pneumatic chamber 8 equipped with a second orifice 10 is provided in front of a first orifice 7 injecting an ink droplet. A valve mechanism 17 for controlling the access of a washing solution 28 is provided to an air supply pipe 15 and the washing solution 28 introduced through the valve mechanism 17 is fed to air and discharged from the second orifice 10 to be made to flow to the pneumatic chamber 8. When the washing solution 28 flows in the pneumatic chamber 8 as it is, the washing solution 28 is mixed in an ink head 1 from the first orifice 7 and, therefore, after the pneumatic chamber 8 is filled, washing is performed. By washing the pneumatic chamber 8 with the washing solution 28 and discharging the washing solution 28 from the ink head 1 through the second orifice, foreign matter in air and an adhered substance can be removed and, therefore, stable printing can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cleaning method for an inkjet printer that cleans an ink head that ejects minute ink droplets.

(b) Prior Art FIG. 6 shows an inkjet printer equipped with a cleaning device that cleans the vicinity of the ink droplet ejection holes of the ink head that ejects minute ink droplets. Cylindrical drum (
[91] supports the recording paper by tightly winding it on its surface, and a guide rod is arranged in the shaft row of the cylindrical drum. The guide rod is a carriage! 2υ is slidably mounted. The carriage (20 has an arch shape extending parallel to the drum surface in the circumferential direction of the end of the cylindrical drum, and has first to fourth ink heads (1a) to (1d) arranged and fixed in a dispersed manner on its inner surface. .These first to fourth heads (
la) to (lb) are magenta, cyan, yellow, respectively.
Each ink of Bunatsuk is jetted, therefore, the cylindrical drum α
9) as main scanning, and the movement of carriage 2υ as sub-scanning, the first to fourth heads (1a
) to (1d), a K color image is recorded on the recording paper α8).

FIG. 7 shows the structure of each of the ink heads (1a) to (ld). Praying heads themselves are well known, and their structure and operation will be briefly described below. When the piezoelectric vibrator (2) deforms in accordance with the recording signal and pressure is applied to the pressure propagation medium in the horn chamber (3), the thin plate (4) provided at the horn chamber opening moves into the ink chamber (6) in contact with it. ) protrude to the side. Ink chamber (
5) is always filled with ink via the ink introduction pipe 02), and therefore, due to the protrusion of the thin plate (4), the ink in front of the protrusion 7 protrudes from the first orifice (7).
Then, the ink droplets (9) are ejected from a second orifice (101) coaxial with the first orifice (7).

Air pumped from the air pump via the air supply pipe α0 is supplied to the first orifice (7) and the second orifice (lO
) and then ejected from the second orifice +1 (1) to form a high-speed air flow. Therefore, the ink droplets (9) With the help of this, it has sufficient flight speed necessary for high-speed records.

By the way, in this type of inkjet printer, since the ink head is close to the recording paper θ barrel during pre-printing, the ink droplets generated when the ink droplets collide with the recording paper Q8) bounce back onto the ejection surface and contaminate the ejection surface. do.

The contamination of the jetting surfaces of the ink heads (la) to (1d) is caused by adsorption of fibers and dust on the recording paper (I fathom), and the ink heads (1a) to (1d) may be left unused for a long period of time. This is one of the causes of clogging of the ink droplet ejection holes.Especially in on-demand type ink heads that eject ink droplets by applying a weak pressure change to the ink near the ink droplet ejection holes, as mentioned above, Because ink droplets are ejected using a weak pressure force, only a gap of a few milliJ is formed between the recording paper and the ink droplets, which causes many ink droplets to bounce back. Clogging cannot be easily recovered by itself.

Therefore, inkjet printers have been equipped with a cleaning member for the purpose of cleaning the ink head before it is left unused for a long time in order to prevent ink droplets from rebounding and adhering to the ink head and adhering to fibers and dust.
It is disclosed in JP 8-128034 and the like.

That is, as shown in FIG.
A row of cleaning devices each equipped with a cleaning member 3υ integrally formed from a porous structure such as foamed urethane or sponge is arranged between the print position and the home position in (1d). ) to (31d) are set to a wet state with water. In the process in which the ink heads (1a) to (1d) move between the print position and the home position, the contact portions (31a) to (31d) of the cleaning member 3υ and the ink heads (la) to (1d) ) is in sliding contact with the jetting surface, and the ink droplets and dust #! It is to be stripped and cleaned.

(c) Problems to be Solved by the Invention The contact portions (31aJ to (31d)) of the cleaning member 3ρ in such a wet state and the ink heads (la) to (31d)
Although a good cleaning effect can be obtained by slidingly contacting the ejection surface of 1d), it is not possible to remove foreign matter such as ink coagulum and dust that adheres to the inside of the ink head. As disclosed in Japanese Patent No. 14757, there is also a method in which ink is filled into the air chamber (8) during non-printing, and this ink is discharged during printing to perform a cleaning operation. However, even in this cleaning operation based on the ink discharge operation, the ink adhering to the nozzle surface could not be sufficiently removed. In particular, with nozzle surfaces that have been treated to be water-repellent for periodic printing, if a small amount of deposits remain, the water-repellency will decrease and cause unstable printing. There were other problems.

2) Means for solving the problem In an inkjet printer equipped with an ink head having an air chamber with a second orifice in front of a first orifice that ejects ink droplets, cleaning liquid is introduced into and out of the air supply pipe. This is a cleaning device for an inkjet printer, characterized in that a valve mechanism is provided to control the flcfq# liquid introduced through the valve mechanism, and the flcfq# liquid is forced into the air, and the cleaning liquid is discharged from a second oriice.

(According to the present invention, by cleaning the inside of the air chamber with a cleaning liquid, ink etc. around the 11th and second orifices can be reliably removed.

(F) Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 5. Incidentally, the same parts as those in the conventional example are given the same reference numerals, and the description thereof will be omitted.

The inkjet printer of this embodiment includes an air pump that appropriately adds air flow (IQ) to the air chamber (8) of the ink head (1) and the ink tank (If) through air supply pipes (15) (15), respectively. (14J is installed, and the air supply pipe between this air pump α brown and the air chamber (8) (
At 151 a valve arrangement αη is inserted. This valve device αη
is composed of, for example, a three-way solenoid valve, and one side of this valve device αη is connected to a cleaning liquid supply pipe that communicates with a cleaning liquid tank (not shown) containing a cleaning liquid such as water via a force 7 plastic + 3). . Furthermore, the supply pipe (4) between the coupler ge+ and the cleaning liquid tank is provided with a pulp example.

I will briefly explain the printing operation of an intjet printer.

FIG. 1 shows a sectional view of the inkjet printer during printing operation. Now, during the printing operation, the aforementioned valve device 0η brings the air pump (14) and the air chamber (8) into communication with each other. The ink droplets ejected from the first orifice (7) are then ejected from the second orifice (10) with the help of the air flow onto the recording paper (I8) wound around the rotating drum. recorded in

Next, the non-printing operation will be explained.

Fig. 2 is a 1Fr side view showing the state during non-printing operation.O During non-printing, the second orifice (10) is covered by the lid (20) and the air chamber (8) is disconnected from the outside. becomes.

Next, in order to supply ink to the air chamber (8) via the ink system from the ink tank to the first orifice (7), the force of the valve device 11 is switched to connect the air chamber (8) to the Σ coupler A. By switching this valve device, the air pressure (8) and the air pop CI are connected to the outside air.

When the air pump (14I) is operated in this state, the air flow (16) flows toward the ink tank (11) and pressurizes the ink in the ink tank (If). Supply pipe: 1211 Ink connector l
5) The ink will be pressurized. Therefore, the pressure of the ink in the ink chamber (6) near the first orifice (7) gradually increases compared to the pressure in the air chamber (8). When this pressure difference reaches a value that breaks the equilibrium state of the ink in the orifice (7), the ink begins to flow from the first orifice (7) into the air chamber (8). . In order to assist the flow of this ink, a piezoelectric vibrator (2) is used.
When an electric signal is applied and the thin plate (4) is caused to vibrate in a continuous manner, the balance of the ink immediately collapses and the orifice (7) of
) the ink begins to flow into the air chamber (8). Once the ink begins to flow, even if the application of the electric signal to the piezoelectric vibrating body (2) is stopped, the pressure (air pressure) in the air chamber (8) will remain unchanged in the ink chamber (
Since the pressure is lower than the ink pressure in step 5), the above ink supply continues. The first orifice in this one envy (7)
The air chamber (8) is covered with cooled ink.

This ink is supplied to the air chamber (8) or the air chamber (8).
) Controlled by the detection output of a suitable detection means provided uniformly in the vicinity of the air supply pipe II.

In this example, the ink droplet ejecting device! tl! The resistance value between the body and the detection voltage η in the insulated air supply pipe Q51 is detected. That is, when the ink rises in the air supply pipe (lω) and immerses the detection electrode M, the resistance value between the podia and the detection electrode M is drastically reduced by the ink, and the completion of ink filling is detected.

Further, if the vibration of the piezoelectric vibrating body (2) is continued until the filling is completed, the filling of ink is not only done quickly but also completely, so this method is usually adopted.

When the detection means detects the end of filling the air chamber (8) with ink, the operation of the air pump 04) is stopped and the pressure of the ink tank (river) gradually decreases.
is suddenly in communication with the outside air via the air/supply pipe (15)k, and in this state, when the pressure of the above-mentioned tapping ink tank, UL, decreases, the ink supplied and filled into the air chamber (8) will flow into the ink tank. (For backflow towards Ill, the valve device αη is closed. Therefore, the air chamber (8) and the air supply pipe system are closed and the backflow of ink is prevented.

As a result, the ink droplet ejecting device (+) is in the home position during non-printing operation, and the air chamber (8) is filled with ink, and the first orifice (7) is covered with the ink, so that drying and Clogging mainly caused by layer dust M is prevented.

Next, the cleaning method according to this embodiment will be explained with reference to FIGS. 3 to 5.

In the cleaning method of the present invention, cleaning is performed by flowing a cleaning liquid such as water into the air chamber (8). However, if the cleaning liquid is directly flowed into the air chamber (8) where only air exists, the first orifice (7) ) may enter the head and have an adverse effect on printing.

Therefore, it is better to perform cleaning after filling the air chamber (8) with the ink described above.

In this embodiment, first, prior to cleaning, an ink filling operation is performed. When the ink filling is completed, the pulp i! , B, - Open and completely fill the coupler 23) with the cleaning liquid. At this time, the valve device +71 is connected to the air pump (1
4) and the air chamber (8) are maintained in communication with each other.

In other words, the coupler and the air supply pipe are connected to each other. When the cleaning liquid is filled into the cup 9A,
As shown in Fig. 4, operate the valve fitting to connect the coupler and the air supply @tube to clean the inside of the coupler mouth.
Guide out the cleaning liquid into the air supply pipe (m). After introducing the cleaning liquid in the coupler (c) into the air supply pipe α, operate the valve device "η, and turn the air pump!+41 into the air chamber (8). At this time, the ink head +11 is placed facing the gutter 4.

In this state, operate the air pump +n)2. Then,
The air supply pipe (cleaning liquid introduced in the country) & flows in the direction of the air chamber (8) by the air flow. First, the ink filled in the air chamber (8) is discharged from the second orifice (lO) opened in the center, and then the cleaning liquid is discharged from the second orifice (lO). The discharged ink and cleaning liquid are captured by a gutter 29) disposed opposite to each other.

When the ejection operation is completed, the air flow (161 stops, the first orifice, 7) maintains the balance of the ink, and the ink head becomes in a standby state. This cleaning operation first causes the ink to flow through the first orifice, 7. ()) and the air chamber (8) in the vicinity of the second orifice 11o), a certain amount of the ink coagulation that has been added to the inner surface of the air chamber (8) is removed, and then the cleaning R# is discharged.
The liquid rises to clean the inside of the air chamber (8), and deposits and the like inside the air chamber (8) can be completely removed.

(G) Detailed explanation of the invention According to the method of the present invention, by cleaning the inside of the air chamber with a cleaning liquid and discharging the cleaning liquid from the ink head through the second orifice, foreign matter and deposits in the air can be removed. Since it can be removed, it is possible to carry out stable memorial impressions.

[Brief explanation of drawings]

1 to 5 are cross-sectional views for explaining each operation of an embodiment of the present invention, FIG. 6 is a perspective view of an inkjet printer equipped with a conventional cleaning device, and FIG. 7 is a typical ink head. This is a new view of (6)...Ink chamber, (7)...First orifice, (8)...Air chamber, tlol...Second orifice, 00...Air supply pipe, (17)... ...Bentso is 1
73...Power pump plastic, 28...Cleaning liquid. Representative Sanyo Electric Co., Ltd. Patent attorney Shizuka Sano Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) An ink chamber filled with ink, a pressure change means for applying a pressure change to the ink chamber, a first orifice that causes ink droplets to be ejected from the ink chamber by the pressure change of the pressure change means, and the first orifice. an air chamber provided in front of the orifice; an air supply pipe for introducing an air flow into the air chamber; and a second hole opened from the air chamber through which ink droplets ejected from the first orifice pass. In an inkjet printer equipped with an ink head consisting of an orifice, the air supply pipe is provided with a valve mechanism for controlling the inflow and outflow of the cleaning liquid, and the cleaning liquid introduced through the valve mechanism is force-fed to the air chamber. A method for cleaning an inkjet printer, characterized in that the inner surface of an air chamber is cleaned by discharging a cleaning liquid from a second orifice.