JPS5998759A - Digital controlling spray gun - Google Patents

Abstract

PURPOSE:To accurately and stably control the amount of a liquid to be sprayed, by connecting a plurality of air supply pipes to be driven on the basis of a binary-coded controlling signal at the top end of a nozzle in a manner such that said pipes intersect the top end with acute angles. CONSTITUTION:A plurality of air supply pipes 25 intersecting the top end of a nozzle with acute angles to be allotted to every order of a binary-coded controlling signal are connected to an air chamber 23 at the top end of a nozzle 20. The effective sectional area of the passage of one air supply pipe 25 corresponding to each order of said controlling signal is controlled so as to become proportional to the power said order of two corresponding controlling signals by a digital-type controller and connected through an electromagnetic switch valve 30 to the source 34 of a pressure fluid. Hence, the control of a spray amount through the nozzle can be accurately performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a digitally controlled spray gun (hereinafter simply referred to as a spray gun), and particularly to a spray gun that can accurately and stably control the amount of liquid to be sprayed.

A liquid injection device called a so-called spray gun that applies Bernoulli's principle does not normally require precise control of the amount of liquid ejected, like a paint spray gun used for painting, for example. However, it is necessary to control the amount of ink ejected precisely and at high speed, as in the case of the ink ejecting spray gun used in ink ejecting printing devices developed by the present inventors and already in use for many years. There are also kimonos. The above-mentioned printing device optically scans the calligraphy manuscript, such as a photographic electrotransmission device or a scanner for printing plate making, and converts the intensity of the obtained image information signal into the amount of ejected ink. This is a device that prints a calligraphic image by jetting ink onto a recording medium such as paper that moves in conjunction with the paper.

As shown in FIG. 1, the ink ejection system of the above-mentioned printing device consists of a cylindrical air nozzle 1 and a cylindrical ink nozzle 2 disposed coaxially and nested inside it. It has a gun 3 and an air flow device J control valve (hereinafter referred to as single [Il+ control valve) 4 connected to the air nozzle 1, and this control valve 4 is integrally connected to a disc-shaped damper 5. is installed in
The center of the damper 5 is caused by the electromagnetic force generated by the interaction between the moving coil 6 supplied with a current according to the image signal and the annular magnetic field formed between the first and second poles 7 and 80. Km installed valve body 9 @
The valve is driven toward the edge and changes the degree of opening of the annular gap between the valve body 9 and the valve seat l according to the image information signal, thereby adjusting the amount of air supplied to the air nozzle 1. This is a moving coil type analog control valve.

Of course, the control valve 4 described above fully performs its intended function,
As mentioned above, it has been operated for many years, but as the control valve of the printing device is required to have a high-speed response of several hundred cycles of 7 seconds, the damper 5 that supports the valve body 9 is severely fatigued. However, there is a problem with a slight lack of operational stability.

Further, since the operating stroke of the valve body 9 is minute and the flow rate changes greatly with a slight displacement of the valve body, there is a disadvantage that a strict level of precision is required for processing and assembling the valve part.

SoC, the present invention, etc.
No. 565, we proposed a new digital type R and quantity control device that can eliminate the above-mentioned disadvantages.

The present invention was made based on the technical knowledge and data obtained through the trial production and research of the above-mentioned digital type FLTT control valve, and its purpose is to develop the above-mentioned digital type FLTT control valve. ! To provide a spray gun that is compatible with a control valve and can accurately and stably control fluid flow rate at high speed.

In order to achieve the above-mentioned object, the invention of - according to the present application has a structure in which a liquid having a controlled flow rate is ejected from the outside of the tip of the nozzle.
An air chamber surrounding this is provided, and an opening that loosely fits coaxially with the tip of the nozzle is provided in this air chamber to form an annular air outlet around the tip of the nozzle. connecting a plurality of air supply pipes that intersect with each other at acute angles and are assigned to each order of the binary coded control signal,
The effective flow path cross-sectional area of the air supply pipe corresponding to each of the above-mentioned 1# signals is determined in proportion to the order power of the corresponding control signal of 2, and each air supply pipe is connected in close proximity to this. It is characterized in that it is connected to a pressure gas source via an electromagnetic on-off valve.

Further, another invention according to the present application provides an air chamber surrounding the outside of the tip of the nozzle from which the liquid whose flow rate is controlled is ejected, and an opening that fits coaxially and loosely into the air chamber with the tip of the nozzle. is provided to form an annular air outlet around the tip of the nozzle, while in the air chamber there are a plurality of air holes that intersect with the tip of the nozzle at acute angles and are assigned to each order of the binary coded control signal. Connect the air supply pipes, and each air supply pipe is connected to a pressure gas source via an electromagnetic on-off valve connected close to it and a pressure reducing valve whose degree of pressure reduction is adjusted according to the order of the corresponding control signal. It is characterized by being made to do.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 5.

In FIG. 2, the symbol 1 indicates a nozzle through which the fluid whose flow rate is controlled (ink in the above-mentioned printing device) flows, and the tip (upper end in FIG. 2) of this nozzle 1C indicates the ink ejection port 2] is open, and the end of the ink flow nozzle connected to the ink ejection port 21 is connected to an ink tank (not shown).

The tip of each nozzle is shaved to a small diameter, and a hollow nozzle cap ρ is screwed together to cover the small diameter portion of the tip of the nozzle. As a result, an annular air chamber B is formed between the tip of the nozzle and the nozzle cap η, surrounding the former. The volume of this air chamber B is set to be relatively small; an opening is provided that loosely fits into the end, and therefore there is a gap between the tip of the nozzle and the nozzle cap η.
, & Annular air eruptions are formed daily.

On the other hand, as shown in FIGS. 2 and 3, a plurality of (eight in the illustrated embodiment) air supply pipes 5.25 are radially connected to the air chamber B from its base side. Each air supply pipe 5
intersects the tip of nozzle I at an acute angle, and
In the illustrated embodiment, the shaft arm is attached to the air chamber B so as to pass through the vicinity of the air ejection date.

In addition, eight first to eighth air supply pipes shown in FIG.
25-7 is provided corresponding to each of binary coded 8-bit configuration flow control signals C8, C1, . . . , C7, which will be described later. = Or
The effective flow path cross-sectional area Di of 1 m 2 +..., 7) is
so that it is proportional to one bundle of 2, i.e. ot= -d(k;
constant). Note that the term "effective flow path cutoff II]" here does not refer to the geometrical cross-sectional area of the air supply pipe 5, but rather to the pressure of the air flow, the viscous resistance between the air flow and the pipe, etc. The effective flow cross-sectional area can be easily determined by experiment.

The spray gun configured as described above is connected to the digital flow surface control device 10 previously proposed by the present inventors, as shown in FIG. 4, for example. Hereinafter, a description will be given of a case where the flow rate control device 10 and the spray gun according to the present invention are applied to the ink ejection system of the printing device.

As described above, in this printing device, a light source and a photoelectric conversion device are disposed inside a calligraphy manuscript 26 made of, for example, a transparent positive painting, which is wound into a cylinder shape, so as to sandwich it and face each other.
For example, the calligraphy original 26 is scanned in a two-dimensional manner by continuously rotating the calligraphy original A once in the direction of the arrow a, and in synchronization with this (rotation) rotation, moving the calligraphy original 26 little by little in the direction of Emian,
In response to the image information signal S output from the photoelectric conversion device path, which detects the shading of circles in parts of the calligraphy and painting manuscript that change moment by moment,
By adjusting the amount of ink ejected from a spray gun, a rose image is transferred and reproduced on a recording medium such as paper that moves in conjunction with a calligraphic original.For color originals, it is possible to transfer and reproduce the rose image in cyan, yellow, and magenta. It goes without saying that multiple systems of ink ejection systems, such as black and black, are required.

Although the control valve 4 shown in the first diagram is directly controlled by the image information signal gSvc as an analog quantity, the flow rate control device 10 shown in the fourth diagram has a built-in AD (analog-digital) converter. It is controlled by the image information signal converted into a binary form by the controller 29Vc. In the embodiment shown in FIG. 4, the image information signal S has, for example, an 8-bit configuration?
6'lJ 14 times C6, C1゜..., C7. These 8-bit digital signals are arranged in such a way that the higher the order, the larger the power number, and a binary code C7C6...c is created by assigning 1 or O according to the bit content of each digit.
Of course, o is proportional to the above-mentioned image information No. 100 S.

Now, the flow rate control embedded shown in FIG. 4 [10 is the air supply pipe Z
The same number (8) of fluid pipes as 5 are connected in parallel with VC, and each fluid pipe corresponds to the valley of the above 1@signal C, and each is equipped with an electromagnetic on-off valve 30. There is.

In FIG. 4, the fluid pipes include an air supply pipe 5, an electromagnetic
yP3o and the air supply pipe 31 are connected in series, and each air pipe 5 is connected to the air chamber formed between the nozzle character fη and the tip of the nozzle 20 (FIG. 2). As I said.

In FIG. 4, the air supply pipe 5 is depicted as being long, but this is simply done to make the drawing clearer; in reality, as shown in FIG. It is desirable to directly connect the output end of the electromagnetic switch-yP31 to the outer end of the air supply pipe z5, and to make the distance between the electromagnetic switch and the air outlet 24 (Fig. 2) as short as possible. .

The other end of each air pipe 31, one end of which is connected to the input end of the electromagnetic switching valve, is connected to a compressed air source 34 having a compressor and an accumulator 33.

On the other hand, the (f+1)th air supply pipe 2. '1-iK is connected to the drive coil of the electromagnetic on-off valve, which corresponds to i? X,
A control signal Ct is supplied, and depending on the bit contents from 1 or 0, the corresponding electromagnetic on-off valve is opened or closed.
It is assumed that the solenoid valve is configured to open when Ci = 1 and close when Ci = 0. In FIG. 4, reference numeral 35 designates an ink tank connected to the nozzle.

A spray gun according to the present invention constructed as shown in FIGS. 2 and 3, and a digital city constructed as shown in FIG. Controlled flow rate? In the printing apparatus equipped with the LIT control device 10, the controller 29 converts the image information signal S as an analog quantity into control signals c, c, . . . as digital signals at a timing of several hundred hertz, for example.
, C7 [convert, knead, lano/I! The fluid pipe is supplied to the drive coil of the electromagnetic on-off valve connected to the air supply pipe 25 corresponding to the r-th order -1, and the fluid pipe leading to the air supply pipe 5 at several hundred hertz according to the bit content of the control signal Ci. Open and close.

Therefore, the flow rate control embedded device 10 that has received the control # signals C6-C7 at a certain instant opens the air supply pipe δ,5 corresponding to the order whose bit content is %1#, and extracts data from the air supply pipe group δ,25. Pressurized air is injected into the air chamber 23 (see FIG. 2). As shown in FIG. 2, most of the pressurized air flow injected from each fat trachea section has a velocity component toward the air jet force, and each air supply pipe 25 intersects the tip of the nozzle at an acute angle. Since it is connected to the air display,
The pressurized air flow injected into the air chamber from each trachea 5 is
Even if multiple streams of pressurized air are injected at the same time, they can be smoothly discharged from the air outlet into the atmosphere without interfering with each other. At this time, a high-speed airflow is generated around the opening at the tip of the nozzle, and the resulting pressure release sucks out the ink in the nozzle 20, and the ink in the nozzle 20 is turned into a mist by the high-speed airflow and ejected from the nozzle. Ink mist ejected from this nozzle flies onto a recording medium such as #, and printing is performed.

By the way, as mentioned above, since the effective flow passage cross-sectional area Di of the air supply pipe 3-i is determined to be proportional to 21,
A jet control signal is generated in the air chamber at a certain moment.2
As mentioned above, the binary number represented by this control # signal is proportional to the image information signal S. The spray gun according to the invention therefore ejects from the air outlet force a pressure air flow that is exactly proportional to the image information signal SVc;
The principle of operation of the spray gun allows an electrical ink mist that is precisely proportional to the image information signal S to be ejected from the nozzle.

The above-mentioned ink mist of 1 liter proportional to the image information signal SK can be obtained when printing a positive image from a negative original, but for example, if the controller Nobuyoshi Ci is inverted with an I/parter (not shown). , it is possible to underestimate the positive image from the positive original.

In addition, the image information signal S is a continuous signal, and the pressure air flow rate controlled by the city is a discrete amount in 256 ways from 0 to 255 (if the city control key C has an 8-bit configuration). Even with other flow rate control devices, including copying devices, if the controlled amount can be divided into 256 steps, it can be considered as a sufficiently continuous amount.If you want to make the gradations even finer, you can
Just increase the number of bits.

FIG. 5 shows an ink ejection system of a printing apparatus similar to that of FIG. 4, which employs a spray gun according to another invention of the present application.

The structure of the spray gun in the same figure is shown in Figures 2 and 3 (
9), except that the effective flow passage cross-sectional area of the six air supply pipes 5 connected to the air chamber 23vc is, for example, all the same (not shown).

In this way, the inner diameter of the air supply pipe will be the same, so
While manufacturing the spray gun becomes easier, the flow rate of pressurized air injected into the air chamber from the air supply pipe 5 does not change depending on the order of the 117i1 elevation C.

Therefore, in the system shown in FIG. 5, pressure reducing valves 36 are connected in series with the electromagnetic on-off valve 30 in the fluid pipe leading from the air supply pipe to the pressure air source 34, and the degree of pressure reduction of each pressure reducing valve 36 is adjusted accordingly. The pressure of the pressurized air supplied to the air supply pipe 25vc is changed by adjusting according to the order of the control signal Ci applied to the fluid pipe [dil].

As is well known, the flow rate of gas flowing through a fluid pipe is constant depending on the pressure of the gas and the effective flow cross-sectional area of the fluid pipe.
Assuming that the effective cross-sectional area of the flow path is constant, the flow rate of the flowing gas is determined primarily by its pressure. therefore,
If the pressure on the secondary side of each fluid pipe line, which has been reduced in pressure by the pressure reducing valve 3b, is determined appropriately, even if the effective flow passage cross-sectional area of each air supply pipe section is the same, the pressure from the air supply pipe 5 to the air chamber can be reduced. The flow rate of pressurized air injected into the air can be made proportional to the order power of the assigned quotient signal of 2. Since the action and effect of the spray gun shown in FIG. 5 are almost the same as those shown in FIGS. 2 to 4, detailed explanation thereof will be omitted.

Note that when the control signal C has an 8-bit configuration, 7?
The degree of pressure reduction of the pressure reducing valve corresponding to the accommodation control signal C7 of 0
The effective flow path cross-sectional area of the next or first order control signal CK (corresponding to the first control signal CK) may be made smaller, and the degree of pressure reduction of the pressure reducing valve 36 may be made smaller accordingly.

In addition to the normal pressure reducing valve that keeps the pressure on the secondary side at one level regardless of the pressure on the negative side, there are also constant pressure reducing valves that keep the pressure difference between the negative side and the secondary side constant. Of course, a pressure reducing valve and a constant ratio pressure reducing valve that maintains the same pressure ratio can be used.

As is clear from the above description, in the present invention, since the tip of the nozzle intersects with the six air supply pipes at an acute angle,
6 Pressurized air flows emitted from the air supply pipe into the air chamber VC can be ejected into the atmosphere from the air outlets independently without interfering with each other, thus making it possible to accurately control the amount of ink ejected from the nozzles. It can be done.

In addition, the electromagnetic on-off valve is placed close to the air supply pipe, and the distance between the output end of the electromagnetic on-off valve and the air outlet is shortened.
Disadvantages that occur when this distance is long, such as the diffusion of a mass of pressurized air that is intermittently discharged from the electromagnetic on-off valve,
This eliminates the distortion of the control Ig caused by the residual pressure air flow even when the control signal is 0, and allows the flow rate of pressurized air ejected from the air outlet to be adjusted accurately in proportion to the control signal. Therefore, it is possible to accurately control the flow rate of the controlled fluid injected from the nozzle.

Furthermore, the control flow rate is determined by opening the selected air supply pipe with an electromagnetic on-off valve, and the electromagnetic on-off valve has two opening and closing times.
Since the flow rate is only in a stable state, it has great effects such as stable flow control.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the structure of a conventional spray gun and a flow rate city 11# device, Fig. 2 is a Vjr curve diagram of a spray gun according to an embodiment of the present invention, and Fig. 3 is its diagram. The front view, Figure 4 is a diagram showing the ink jetting system of the printing device incorporating the spray gun, which is the invention of the present applicant, Figure 5.
The figure is a diagram showing an ink ejection system of a printing device incorporating a spray gun according to another invention related to the present MVC. Δ)-/, e-ru, 2]...Ejection port, etc....Nozzle cap, Ode...Air type, Jun...Air injection port, 25.
... Air supply pipe, blade... Solenoid on-off valve, A... Pressure nitrogen source, 36... Pressure reducing valve. Patent applicant: Japan Enraging Color Co., Ltd. Figure 1 Figure 4

Claims (1)

[Claims] 1. An air chamber surrounding the nozzle is provided outside the tip of the nozzle from which the liquid whose flow rate is controlled is ejected, and an opening is provided in the air chamber to coaxially fit with the tip of the nozzle. While forming an annular air jet nozzle TL around the tip of the nozzle, the air chamber has a plurality of holes intersecting the tip of the nozzle at acute angles and assigned to each order of the binary coded control signal. The air supply pipes are connected, and the effective flow path cross-sectional area of the air supply pipe corresponding to each order of the control signal is determined to be proportional to the order of 29 corresponding control signals, and each air supply pipe is connected to the order of the control signal. A digitally controlled spray gun characterized in that it is connected to a pressure gas source (vc, tt) through an electromagnetic on-off valve connected to it. 2. Is the above air supply pipe the central axis of the nozzle tip? fMKt5
A digitally controlled spray gun according to claim 1, characterized in that the spray gun is connected radially. 3. The digitally controlled spray gun according to claim 1 or 2, wherein the air supply pipe is connected to the air chamber so that its central axis passes near the air jet port. 4. Provide an air chamber surrounding the outside of the tip of the nozzle from which the liquid whose flow rate is to be controlled is ejected, and provide an opening in this air chamber that loosely fits coaxially with the tip of the nozzle to surround the tip of the nozzle. while forming an annular air outlet, a plurality of air supply pipes each intersecting the tip of the nozzle at an acute angle and assigned to each order of the binary surface control signal are inserted into the air chamber; Each air supply pipe is connected to a pressure gas source via an electromagnetic on-off valve connected close to it and a pressure reducing valve whose degree of pressure reduction is adjusted according to the order of the corresponding control signal. Features a digitally controlled spray gun. 5. Is the above air supply pipe the central axis of the nozzle tip? 5. Digitally controlled spray gun according to claim 4, characterized in that it is connected radially with respect to fMK. 6. The digitally controlled spray gun according to claim 4 or 5, wherein the air supply pipe is connected to the air chamber so that its central axis passes near the air outlet.