SU865139A3 - Device for forming drops of liquid in sprayed printing - Google Patents

Description

one

This invention relates to a device for applying liquid droplets on a recording surface.

The speed of data recording on paper, the Eschrimer in the data processing system, is primarily limited by the capabilities of the recording mechanism, which in many cases are much lower than the possibilities from the data processing.

I In ink ejection mechanisms, liquid is ejected onto the paper by applying electrical pulses, the liquid being ejected by a series of pulsed droplets II.

The speed of the recording mechanism is largely determined by the ability of the fluid to respond to high-speed electrical pulses. The voltage during the formation of electrical impulses must be high enough to overcome the resistance exerted by the fluid due to its surface tension and viscosity.

The closest technical solution to the invention is an assembly for forming liquid droplets that can be used for inkjet printing, comprising a housing.

in which you perform: the first chamber placed on a piezoelectric pulse generator, filled with a liquid; a bone, a second chamber with an axial output channel filled with liquid and connected by an axial intermediate channel with the first chamber and a peripheral inlet channel with a source of liquid supply, a mixing chamber

10 and a source of compressed air 2.

However, these mechanisms have a narrow dynamic range, resulting in a relatively large liquid droplet formation.

15 and, therefore, satisfactory image gradation cannot be obtained on the recording surface. When recording, droplets of liquid are ejected onto a sheet of paper, covering a roller rotating at high speed. Since a series of droplets are formed when they are emitted in response to a single electric pulse, they tend to hit different

25 surface areas for recording, thereby causing the formation of a blurred spot in the image. Besides . In addition, high-speed rotation of the roller causes flow swirl.

30 air at the surface, which can cause dispersion of the ejected droplets.

; The purpose of the invention is to increase the speed of the device and improve its performance.

The goal is achieved due to the fact that the mixing chamber consists of: a disc-shaped cavity with an output channel, coaxial with the output channel of the second chamber and an intermediate channel connected to it by an external annular cavity, on the periphery of which a tangential input channel is connected to a source of compressed air connected. to the source of fluid supply.

In addition, the device contains a static pressure regulator associated with a fluid supply source.

The diameter d of the axial output channel of the second chamber and the height H of the disk-i. different cavity vortex mixing chamber is made in accordance with the ratio

I 0.25 - 0.50.

The drawing shows the proposed device.

The device comprises a housing 1 in which a first chamber 2 is made for a liquid applied to the surface. The chamber is placed on a piezoelectric generator designed to create short-term spikes in fluid pressure in the first chamber. In the housing there is a second chamber 3 for fluid, connected to the first chamber by means of an axial intermediate channel 4 and having an axial outlet channel 5, which is centered with channel b and is in close proximity to it, due to which a short-term surge of fluid pressure in the first The chamber causes the appearance of a series of drops of liquid that fly out through the first channel b. The second fluid chamber has a peripheral inlet 7, connected to a fluid supply source 8. The housing 1 has an air mixing chamber 9, which is divided into a disk-shaped cavity 10 with an OUTLET channel 11, as well as an external annular cavity 12, which has a tangential inlet channel 13 connected to the source 14 of compressed air, and channel 11 is centered with channel 5 and It is located in close proximity to it. In addition, there is a device 15 designed to provide communication of a source of fluid supply with a source of compressed air to increase the static pressure of the fluid in the source of supply to such an extent that the static pressure in channel 5 becomes equal to the static pressure in the space between the channel 5 and eleven.

In the device, the static pressure on the boundary surface of the fluid in channel 5, i.e. on the surface that separates the fluid in channel 11 from the space between channels 5 and 11 ,. Is balanced. This helps to reduce the surface tension of the boundary surface or layer of fluid in channel 5, and also contributes to the ejection of fluid into the surrounding

The Q space is through channel 11. This, in turn, reduces the minimum excitation voltage applied to the piezo-electric generator, as a result of which it is possible to reproduce the very fine nuances of the original painting. After applying a single electric pulse to the piezoelectric generator, through channel 5, a series of drops of liquid flies out, the size of which decreases by the end. Due to the presence of airflow, outgoing droplets with a smaller size accelerate faster because they have less inertial capacity than

5 large droplets, so smaller droplets are combined with large droplets to form a single droplet that falls on the same point of the drawn surface. This eliminates the blurring of the image that. otherwise, it may be obtained after depositing such a series of drops on the surface of the letter.

Formation of a single drop after

with the application of a single electric pulse to the piezo-electric generator causes the gap between successive drops, and it is also possible the appearance of an additional drop between successive

0 drops by increasing the frequency of the excitation pulse. Thus, the volume of printing ink ejected per unit of time increases, ensuring that the device operates at a higher speed, i.e. the writing surface can be moved at a higher speed relative to the device. Since the speed with which,

0, the writing surface moves or rotates on the drum relative to channel 11. such that air turbulence takes place directly in the vicinity

f of the surface of the letter, the air flow directed towards the surface of the letter overcomes this air turbulence and ensures the successful application of droplets of any size at predetermined positions.

0 In order to increase the stability of the proposed device, the fluid supply source 8 is completed with a static pressure regulator 16. o The proposed device allows a higher speed.

Claims (3)

Claim 1. A device for forming liquid droplets for inkjet printing, comprising a housing in which a first chamber filled with liquid, arranged on a piezoelectric pulse generator, and a second chamber with an axial output channel filled with liquid and connected by an axial intermediate channel to the first camera and peripheral are made inlet channel with a source of fluid supply, a mixing chamber and a source of compressed air, characterized in that, in order to increase the speed of the device and improve its operational characteristics Teristik, the mixing chamber consists of a disk-shaped cavity with an output channel, coaxial with the output channel of the second chamber and an intermediate channel connected to it by an external annular cavity, at the periphery of which there is a tangential inlet channel connected to a source of compressed air connected to a source of fluid supply. I 2. The device pop. 1, characterized in that it contains a static pressure regulator associated with a fluid supply source. 3. The device according to claim 1, characterized in that the diameter d of the axial output channel of the second chamber and the height h of the disk-shaped cavity 15 vortex mixing chamber made in accordance with the ratio | = 0.25 - 0.5.