JPS6249188B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device, and more particularly to an inkjet recording device that charges ink particles with an information signal and performs recording by applying the charged particles to a recording medium. .

First, the operating principle of the recording method to which the apparatus of the present invention is applied will be explained with reference to the schematic diagram of an inkjet recording apparatus shown in FIG.

In the figure, 1 is an ink particle generation part, 2
3 is the recording body, 3 is the nozzle of the ink particle generation section 1,
4 is an electrostrictive element incorporated in the nozzle 3, 5 is an ultrasonic power source, and 6 is an ink particle.

7 is a charging electrode, 8 is an information signal source, and 9 is a deflection electrode section.

Further, 10 is a gutter, 11 is an ink tank related to an ink bottle, 12 is a pump (PF), 13 is a regulator, 14 is a solenoid valve, and P is a pressure gauge.

That is, the recording body 2 is configured to record characters while making a relative movement with the ink particle generating section 1, for example, as indicated by arrow A in the figure.

Pressurized ink is applied to the nozzle 3 of the ink particle generating section 1, and the electrostrictive element 4 incorporated in the nozzle 3 is connected to an ultrasonic power source 5.
A voltage is applied to force the pressurized ink to vibrate, and the ink ejected by this vibration becomes ink particles 6,
The number of generated waves is the same as the frequency of the ultrasonic power source 5.

An information signal source 8 for charging the ink particles 6 is connected to the charging electrode 7, and these constitute an information signal charging section.

The ink particles 6 charged as described above are deflected in proportion to the amount of charge by the voltage of the deflection electrode section 9, and reach the moving recording medium 2 to form characters. Ink particles 6 that are not used for printing are captured and collected by the gutter 10.

The circulation process starts from the ink tank 11 to the pump 12.
is pressurized, the pressure is regulated by a regulator 13, and the pressure is guided to the nozzle 3 via a solenoid valve 14.

As mentioned above, after being collected from the gutter 10, the ink 15 is returned to the ink tank 11, and the collected ink 15 is again guided to the nozzle 3 through the above-mentioned path to be used repeatedly. It is.

In short, the above-mentioned ink tank 11, pump 12, regulator 13, solenoid valve 14, nozzle 3, gutter 10, etc. form a circulation section.

By the way, basically, in order to create the ink particles, it is necessary to maintain the physical properties of the ink itself, such as viscosity, surface tension, specific gravity, and specific resistance for imparting conductivity to the ink, within a predetermined range. be.

However, in a method that involves circulating and reusing ink, such as the method used in the inkjet recording device described above, the physical properties of the ink change during the circulation process, particularly during the jet flight and during the process of being collected by gravity from the gutter. Some of the solvent components of the ink volatilize and fluctuate.

In order to suppress this fluctuation as much as possible and extend the life of the ink, various methods have been adopted in the past.

It may be a little confusing here, but in general, ink consists of solids such as resins and dyes, and a solvent.The solvent component in this ink is often composed of multiple components, and the component ratio of the volatilized solvent is as follows: This is different from the solvent component ratio of the ink. The volatile components can be determined by roughly calculating them based on the vapor pressure of each solvent, or by directly analyzing the volatile components.

Accordingly, one method of extending the life of the ink mentioned above is to replenish the solvent corresponding to the volatile components.

FIG. 2 is a schematic configuration diagram of the solvent replenishment device according to the exemplary replenishment method. This shows a solvent, and the illustrated recovery side and supply side correspond to the same display in FIG.

That is, an auxiliary tank 16 is installed above the ink tank 11, and a solvent 17 corresponding to the above-mentioned volatile components is put inside, and as the liquid level of the ink 15 decreases, the solvent 17 is automatically transferred to the ink tank 11.
This is to replenish up to a certain level.

However, in this method, since the solvent 17 is replenished to the amount of ink used for printing, the solid content such as dyes and resins in the ink decreases, or the solvent component of the ink decreases.
As mentioned above, there is a drawback that the volatile components are approached with respect to different solvent component ratios.

Therefore, a method was further devised in which the amount of ink to be used for printing was estimated in advance and an improvement was made by adding an ink component to the solvent 17.

Although these methods have considerably extended the ink life compared to the case of using ink alone, a complete solution has not yet been reached because the amount of ink consumed cannot be uniformly determined.

In view of the drawbacks of the prior art as described above, it is an object of the present invention to provide an inkjet recording device that eliminates the drawbacks, significantly extends the life of the ink, and provides a method for automatically replenishing the ink. , that is its purpose.

The main points of the present invention are, first of all, that the amount of volatilization of ink in an inkjet recording method can be regarded as approximately a function of the operating time if the arrangement conditions of the piping system and the surrounding environment conditions are constant. Heading, confirm this by experiment,
The solvent is automatically and efficiently replenished based on the operating time, and secondly, the replenishment supply section in the solvent replenishment device section is opened and closed discretely, making it possible to replenish minute amounts. That's the point.

That is, the configuration of the inkjet recording device of the present invention includes an information signal charging section that charges ink particles to charge them, a deflection electrode section that deflects the charged particles and makes them adhere to the recording medium, and a system that circulates the ink. The apparatus is equipped with a circulation section designed to be reused, charges ink particles with an information signal, deflects the charged particles, causes them to adhere to a recording medium for recording, and circulates the ink for reuse. In the recording device related to the desired cyclical reuse method,
An auxiliary tank for storing ink is provided between the recovery side and the supply side of the circulation section and is formed so that ink can be replenished as the liquid level drops, so that ink replenishment work can be performed automatically. The ink bottle configured as above is comprised of a counter used to time the operating time and a means for giving a counting signal to the counter during ink ejection, and generates a discrete signal from the operating time during ink ejection. A storage tank containing a solvent corresponding to the volatile components of the ink is connected via a replenishment supply section that is controlled by a control device and replenishes a predetermined amount of solvent when the counter reaches a predetermined value. , the ink bottle is conveniently configured to automatically fill the ink bottle with a solvent corresponding to the volatile components of the ink in a discrete manner in proportion to the operating time during ink jetting.

In short, the present invention aims to maintain the balance of the ink components, and is capable of achieving this with a simple configuration. A fixed amount of solvent is replenished at each ink ejection time, and the amount of replenishment is controlled, and the work of replenishing the ink used for printing can be performed automatically.

Next, embodiments according to the present invention will be described with reference to the drawings.

First, FIG. 3 is a schematic configuration diagram of a solvent replenishing device section in an inkjet recording apparatus according to an embodiment of the present invention. As in the above, 11 is an ink tank related to an ink bottle, 15 is an ink tank, and 16A is an ink tank related to an ink bottle.
17 is a solvent corresponding to the volatile components of the ink (hereinafter simply referred to as solvent); 18 is an auxiliary tank having an opening at the top related to the storage tank; 19 2 is a solenoid valve, and 20 is a throttle valve, and these solenoid valve 19 and throttle valve 20 form a replenishment supply section.

The illustrated collection side and supply side correspond to the collection side and supply side in FIG. This corresponds to a system in which a solvent replenishing device shown in FIG. 3 is provided between the system and the supply side, and will be described below accordingly.

That is, as shown in FIG. 3, in general, an auxiliary tank 18 having an opening at the top and an ink tank 11 are connected, and a solenoid valve 19 is installed between them.
and a throttle valve 20, and an auxiliary tank 16A having the same auxiliary function as the auxiliary tank described in FIG. It is something that

As a result, when the solenoid valve 19 is turned on during operation, the solvent 17 is automatically added to the ink tank 11.
is replenished at a substantially constant rate, which not only extends the life of the ink, but also allows the ink replenishment work to be performed automatically.

However, in reality, the volatilization rate of the ink solvent component is generally a small value of 1 c.c./hour or less, which puts a limit on the ability of the throttle valve 20.

To deal with this, in this embodiment, the electromagnetic valve 19 is opened and closed discretely to enable replenishment of a very small amount.

In short, for example, the opening of a three-way solenoid valve can be intermittently interrupted by pulses.

That is, FIG. 4 shows an embodiment of a control circuit related to a control device that generates discrete signals from the operating time during ink ejection, which is used to discretely open and close the solenoid valve 19.

In the figure, 19 is the above-mentioned solenoid valve, and 2
1 and 22 are oscillators (OS1 and OSC2) that output pulses of frequencies f ₁ and f ₂ , respectively; 23 and 24 are
AND gate, 25 is an up-down counter (U/D counter), 26 is a flip-flop, 2
7 is an amplifier.

Also, A and B are the outputs of the AND gates 23 and 24, C is a carry signal, D is a borrow signal, E is a set signal, F is a reset signal, and I is when ink is ejected from the previous nozzle 3. D, U, CA, and BO are the countdown terminals of the up-down counter 25, respectively.
These are count up terminal, carry terminal, and borrow terminal.

Therefore, the frequencies f ₁ of the oscillators 21 and 22,
The ratio to f ₂ corresponds to the ratio between the amount of ink volatilized per unit time and the flow rate of the solvent 17 passing through the solenoid valve 19, and generally, the frequency f ₂ is lower than the frequency f ₁
is considerably larger.

As mentioned above, the signal I is assumed to be "1" when ink is ejected from the nozzle 3, and is output from the AND gate 2 together with the output of the frequency _f1 of the oscillator 21.
This is what is input in 3.

This AND gate 23 also receives the output of a reset signal F from a flip-flop 26, which will be described later, and its output A is sent to the up-down counter 25.
It is connected to the count up terminal U of.

On the other hand, the output of the frequency f ₂ of the oscillator 22 is combined with the output of the set signal E of the flip-flop 26.
is input to AND gate 24, and this AND gate 2
The output B of 4 is connected to the countdown terminal D of the up-down counter 25.

The up-down counter 25 mentioned above is
When a pulse signal is input to the count up terminal U or count down terminal D, it counts up or down.When the count value reaches a certain value, a carry signal C is generated, and when the count value returns to zero, a borrow signal is generated. Signal D is output.

The flip-flop 26 is set by the carry signal C and reset by the borrow signal D, and is in the set state, that is, the set signal E.
When the output is "1", the solenoid valve 19 is driven via the amplifier 27, and the solvent 17 passes through.

In short, in the control circuit related to the control device shown in FIG. 4, at least the up-down counter 25 is related to a counter used to time the operating time, and similarly, the oscillators 21, 22, The AND gates 23, 24 and a state signal generating means (not shown) for the signal I related to the state signal are related to means for giving a count signal to the counter during ink ejection, and the solenoid valve 19, the throttle valve 20 relates to a replenishment supply unit that is a means for replenishing a predetermined amount of solvent when the counter reaches a predetermined value.

Next, the recording operation according to the above embodiment is as follows.
This will be explained using the time chart shown in FIG.

First, in the initial state, the count value of the up-down counter 25 is zero and the flip-flop 26 is in a reset state.

At this point, ink jetting starts from nozzle 3,
When the signal I becomes "1", the AND gate 23 opens and the output of the frequency _f1 of the oscillator 21 is input to the up-down counter 25, and counting up starts.

As the count-up progresses and the count reaches a certain value, a carry signal C is output, the flip-flop 26 enters the set state, and a set signal E is output.
The output of the reset signal E becomes "1" and the output of the reset signal E becomes "0".

Therefore, AND gate 23 closes, and conversely,
The AND gate 24 opens and the up-down counter 25 starts counting down from a certain value.

The frequency f ₂ related to the output of the oscillator 22 is
1, the borrow signal D is output in a shorter time than the illustrated count-up time _T1 , and the countdown ends.

During the countdown, the solenoid valve 19 is driven and the ink tank 11 is replenished with the solvent 17.

Further, when the countdown ends as described above, the flip-flop 26 goes into the reset state again and starts the count-up operation described above.

As mentioned above, in this example, the above-mentioned time
Every time ink is ejected from nozzle 3 by T ₁ ,
The solenoid valve 19 is opened for the illustrated time _T2 .

Here, the times T ₁ and T ₂ are inversely proportional to the frequencies f ₁ and f ₂ which are the oscillation frequencies of the oscillators 21 and 22, respectively.

On the other hand, the ratio between the frequencies f ₁ and f ₂ above corresponds to the ratio between the amount of solvent volatilized per unit time and the flow rate of the solvent 17 passing through the electromagnetic valve 19 .

Therefore, the solvent 17 that volatilizes during the time T ₁
The amount of ink is equal to that replenished during time T ₂ , so the ink can always be kept constant.

However, in the case of industrial inkjet printers, there are differences in the arrangement conditions of the piping system or the environmental conditions at the location where the device is installed, which naturally causes differences in the amount of volatilization of the solvent 17 in many cases. In such a case, it is obvious that the settings related to the oscillators 21 and 22 described above may be made variable.

According to the inkjet recording device as described above,
This greatly extends the lifespan of ink and allows for automatic ink replenishment.

In addition, in the above embodiment, as shown in Fig. 3, the method of supplying the solvent by gravity was explained, but this is not limited to such a method, and the supply of the solvent is not limited to such a method. Needless to say, when this is controlled discretely, there is no problem in replenishing this very small amount.

Further, the amount refilled by the above-mentioned embodiment is not limited to the amount that has been volatilized, but also the amount of ink used for printing can be automatically refilled.

As a result, it is possible to obtain a recording apparatus that not only extends the life of ink but also can automatically perform ink replenishment work.

In summary, according to the present invention, it is an object of the present invention to provide an inkjet recording device that circulates and reuses ink, and is capable of increasing the lifespan of the ink and automatically replenishing the ink. This invention can be said to have excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an ink jet recording apparatus that also shows the operating principle of the recording method that is the object of the present invention, FIG. 4 is a schematic configuration diagram of a solvent replenishment device section in an inkjet recording apparatus according to an embodiment of the present invention, and FIG. 4 is a control device according to an embodiment used to control the replenishment supply section The circuit diagram and FIG. 5 are its time charts. 1... Ink particle generation part, 2... Recording body, 3...
... Nozzle, 4 ... Electrostrictive element, 5 ... Ultrasonic power supply,
6... Ink particles, 7... Charged electrode, 8... Information signal source, 9... Deflection electrode section, 10... Gutter, 1
1... Ink tank, 12... Pump, 13...
Regulator, 14... Solenoid valve, 15... Ink, 16, 16A... Auxiliary tank, 17... Solvent corresponding to volatile components, 18... Auxiliary tank having an opening at the top, 19... Solenoid valve, 20 ... Throttle valve, 21, 22... Oscillator, 23, 24...
AND gate, 25...up-down counter,
26...flip-flop, 27...amplifier.

Claims (1)

[Claims] 1. An information signal charging section that applies an electric charge to ink particles to charge them, a deflection electrode section that deflects the charged particles and causes them to adhere to a recording medium, and a circulation section that circulates the ink for reuse. A recording device according to a cyclical reuse method, which is equipped with the following: ink particles are charged with an information signal, the charged particles are deflected and attached to a recording medium for recording, and the ink is circulated and reused. In this method, an auxiliary tank for storing ink is installed between the recovery side and the supply side of the circulation section and is formed so that ink can be replenished as the liquid level drops, and the ink replenishment work is automatically performed. The ink bottle is configured such that the ink bottle is composed of a counter used to time the operating time and a means for giving a count signal to the counter during ink ejection, and a means for providing a count signal to the counter during ink ejection. A storage tank containing a solvent corresponding to the volatile components of the ink is supplied via a replenishment supply section that is controlled by a control device that generates the solvent and replenishes a predetermined amount of solvent when the counter reaches a predetermined value. 1. An inkjet recording apparatus characterized in that the inkjet recording apparatus is configured such that a solvent corresponding to volatile components of the ink is automatically filled into an ink bottle discretely in proportion to the operating time during ink jetting.