WO2017168365A1

WO2017168365A1 - Cleaning and chemical recovery system and operating method thereof

Info

Publication number: WO2017168365A1
Application number: PCT/IB2017/051828
Authority: WO
Inventors: Edmundo Lúcio DA COSTA MARQUES
Original assignee: Da Costa Marques Edmundo Lúcio
Priority date: 2016-03-30
Filing date: 2017-03-30
Publication date: 2017-10-05

Abstract

The present invention relates to a system for cleaning and recovering chemical values, in particular pH and electrical conductivity parameters (E.C.) of the water in wetting systems for offset printing machines. The disclosed systems makes it possible to remove suspended matter and to recover the chemical properties of the water in wetting systems for offset printing machines. As a result, water consumption is reduced and cleaning and maintenance times are shortened, at the same time as the quality of printing is improved because of homogeneous lithographic plate wetting conditions. This invention was developed to work in parallel with offset printing machines without requiring any adaptation or any alteration of the printers, both sheet-fed printers or rotary printers for newspapers and magazines.

Description

DESCRIPTION

"CHEMICAL CLEANING AND REPLACEMENT SYSTEM AND ITS METHOD OF

OPERATION"

Technical Domain

The present technology discloses a cleaning and chemical replacement system, namely the properties relating to pH and Electrical Conductivity, C.E., present in the water of offset printing machine wet systems.

Background

The offset printing process, in short, consists of a lithographic plate and its set of rollers that carry the image to paper, ink and water.

When the plate is inserted into the printing press, when it receives the backing of the inking rollers, it is completely covered with ink, even where it has no information to print. Here comes the function of water, water. Water is a water solution made up of chemical additives that allow the pH and EC to be maintained. at predefined intervals (4.8 <pH <5.3 and 800 <EC. <1250 μΞ / αη). The action of wetting on the plate is to clean the excess ink, leaving only the area with information to print with ink.

For this, the water must have the ability to always be stable at various levels for constant cleaning.

However, the printing process suffers from various sources of dirt and contamination:

the paper, depending on the type to be printed, coated (the most commonly used paper in catalogs, magazines, etc.) and uncoated (most used in paper, newspapers, etc.), releases dust-based particles, which are mostly composed of limescale agents;

- the paint, as it is in constant contact with the water in the plate cleaning, also contaminates the water;

- Other chemicals, for washing the machine between work or not, are used some thinners which themselves come into contact, albeit reduced, with the water;

- Alcohol is used in the composition of the wet as a cooling agent function, thus increasing the tension of water in cleaning the plate.

In short, all these soiling agents cause the imbalance of water both in soiling (suspended matter) and in the chemical composition of water (pH and EC).

In general, a machine maintenance procedure provides for thorough cleaning of the water circuit once a week. After cleaning, the machine starts production with the chemical values at the desired intervals, however, as the days go by, they change (increasing) rapidly causing various problems in the printing process.

Some problems are related to the increase / decrease of dot gain, the print starts to get more "loaded", losing detail reading in images, the most common effect is the grain seen in the images. The balance of the water of the wets is fundamental, because it is from the water that the excess ink is cleaned in the plate, so that the dot transfers to the correct size paper and reproduces the image correctly. The lower the water cleaning capacity, the more the point increases in size. In addition, there is an imbalance in neutral balancing, starting to print with different shade trends in the compound grays.

The plates also lose contrast during printing, especially over long runs, and as a result the printing becomes dull and without contrast.

Briefly, in the offset printing process, there are 3 key factors, paper, ink and water solution. The water is used to remove excess ink from the lithographic plate, leaving only what is needed to print what you want. Under normal conditions, wetting is a solution composed of water, added to a pH and C.E. regulating additive, and alcohol.

In the regular operation of the printer, after 2 to 3 days the water loses its desired properties, becoming dirty, with the accumulation of paper dust, ink residues and other products, as well as its chemical composition, because the materials The above mentioned suspended suspensions, due to their chemical compositions, change their pH and EC properties.This evolution in water conditions means that operators at the end of each working week have to stop the machine to clean the entire wetting system and fill it with a new water solution.

The water systems of the printers are composed of a cooling tank and two dosers, one for pH and CE control chemical additive. and another for alcohol. We In the same tanks there is a probe (alcohol meter) which when detecting that the volume of alcohol is above or below the programmed by the operator, opens or closes the alcohol intake during the supply of mains water to the printer. In the case of the chemical additive dispenser, it only passes the percentage per liter set during the water supply to the printer. As a result, the printer's operating system and its water system do not control the dirtiness of suspended matter or the chemical properties of water. Herein lies the major factor responsible for the water deterioration of offset presses.

These changes in water properties cause numerous printing problems, in addition to all the environmental costs such as uncontrolled color reproduction (dot gain and overprinting), deterioration of lithographic plates and mechanical malfunction as the color increases. situation.

In short the control of water properties is crucial for a good offset printing process, as 60% of the print control at the point and overprint level should be complemented by

to water.

summary

A cleaning and chemical replacement system for offset presses is disclosed, comprising:

- A control unit with storage and data processing facilities configured to manage the operation of: - At least one pneumatic water extraction pump;

- At least one cleaning block;

- At least one block of sensory instrumentation;

- At least one chemical replacement block.

In a particular embodiment of the system the control unit is physically connected to the pneumatic pump and the cleaning, sensory instrumentation and chemical replacement blocks.

In a particular embodiment of the system the control unit comprises a wireless communication module configured to communicate with the pneumatic pump and the cleaning, sensory instrumentation and chemical replacement blocks.

In a particular embodiment of the system the pneumatic pump and the cleaning, sensory instrumentation and chemical replacement blocks have a wireless communication module configured to communicate via the wireless communication protocol with the control unit.

In a particular embodiment of the system the cleaning block comprises at least two sequentially placed filtering units one after the other.

In a particular embodiment of the system a filtering unit has a filtering mesh whose mesh opening is larger than the mesh opening of the succeeding filtering unit.

In a particular embodiment of the system the opening of The mesh is in the range of 5 to 25 microns.

In a particular embodiment of the system the sensory instrumentation block comprises at least one electronic pH measuring instrument and at least one electronic electrical conductivity measuring instrument.

In a particular embodiment of the system the chemical replacement block comprises at least one resin cell and at least two reagent tanks.

Also disclosed is the method of operation of the cleaning and chemical replacement system for offset printers, characterized by:

- periodic activation of the operation of the pneumatic pump by the control unit, activating the printer's water extraction circuit;

- collection and storage of data from the sensory instrumentation block by the control unit;

- comparison in the control unit of the values collected with those previously defined;

- actuation of the control unit in the chemical replacement block, specifically in the resin cell and reagent tank feeders, if the collected values fall within the range of the defined values.

In a particular embodiment of the method the operating period of the pneumatic pump is programmed by the user.

In a particular embodiment of the method the control unit is programmed to operate in three modes of different operating conditions depending on the system's hydraulic pressure and desired flow rates.

General description

The present technology solves the technical problem of cleaning and resetting the chemical property values of water in offset printing machine wetting systems.

A system of cleaning and replacement of chemical values is disclosed, namely the pH and EC parameters. present in the water of offset printing machine wet systems.

The system presented comprises a pneumatic pump that allows to create a circuit that provides the collection and return of water to the printer. This being collected by the pump is led through a pipe circuit to the cleaning stage, where two sequential filtration units are in charge of this task. Each unit has a filtering mesh: one wider mesh in the first unit and one closer in the second. The opening of each mesh can range from 5 to 25 microns, depending on the type of media to be printed - the dirt from paper used in a packaging printing company is thicker than the dirt released from paper used in a catalog printing company. The pipe circuit then conducts water to the pH and EC measurement stage. These measurements are made by two electronic instruments that have unique probes for measuring the parameters concerned. These probes are connected to the control unit, which performs the scheduled collection of said probes. values, being stored and processed. The entire action of the control unit is managed by a microprocessor type electronic processing device. Based on the values collected by the probes, the control unit compares them with the reference values programmed by the operator. If these are outside the pre-set intervals, the control unit will operate a resin cell to make the necessary EC compensations. by ion substitution. In addition, the reagent tank feeders, which are responsible for balancing the pH of the water and the corresponding chemical replenishment of its properties, are controlled by the control unit, which carries out all the necessary water treatment before it is re-run. to the printer circuit, now completely clean and properly treated. The above reagents are water solutions with low acid or alkaline concentrations which allow the pH to be raised or lowered. Being a closed circuit between the printer and the machine, every 5 minutes on average, all water in the printer's water system passes through the chemical cleaning and replacement system. The operating period of the system is controlled by the control unit, which controls the action of all its constituent blocks, from the pneumatic pump to the cleaning and chemical replacement stages.

Thus the system presented allows the cleaning of suspended materials and the replacement of the chemical properties of water, existing in the wet systems of offset printing machines.

As a consequence, there is a reduction in water consumption and cleaning and maintenance times, as well as an increase in print quality through the homogeneity of the wet conditions on the lithographic plate. This technology is designed to work in parallel with offset printing machines, without any need for any adaptation or any intervention on the printers, whether they are sheet-fed or rotating newspaper or magazine, as the printer is simply connected. cleaning system directly to the printer's water supply system, operating as a closed circuit

The system developed will allow all cleaning of suspended materials from printing units, such as paper dust, waste ink and lithographic plates. After this process, it will measure water conditions, pH and C.E., and adjust them to the values set in the control unit.

The present invention is useful for reducing corporate environmental costs by reducing machine water cleaning and maintenance cycles, increasing the homogeneity of water conditions, providing improved print quality such as higher ink gloss, better control of dot gain and over printing and better ash balance.

In a particular embodiment, the system may be connected to more than one printer, specifically to its water supply system, thereby enabling uniformity of printer wetting solutions. To do this, there are 3 operating models programmed into the control unit, which differ in system hydraulic pressure and appropriate flow rates for the number of printers in which it is installed. When the machine is connected to more than one printer, in the user interface of the control unit, a period of interaction with each machine will be scheduled and scheduled. After this time has elapsed, the control unit gives the command to close the printer circuit, opening the circuit of another printer and so on cyclically.

The technology presented intervenes in the field of balancing the quality of wet conditions of offset printing machines.

Its main function is to clean the suspended matter from the paper dust and paint residues and to balance the chemical conditions of the corks by keeping their values in the user-defined goal as their working ideals. With the intention of the equipment in the process, the problems that this solves with the homogeneity of the wets, allows to improve: the mechanical point gain control of the printing;

the color balance between a printed ink and after drying, causing no deviations;

the balancing of compound neutrals and ink overprinting;

the longevity of lithographic plates over long runs;

eliminate the inherent times and costs of weekly maintenance of corks;

cost reduction with wetting additives;

reduction and / or elimination of alcohol consumption in

print . Description of the Figures

For an easier understanding of the present application, attached are figures which represent preferred embodiments which, however, are not intended to limit the art disclosed herein.

Figure 1 schematically depicts the cleaning and chemical replacement system shown, wherein the reference numerals represent:

1- Pneumatic pump;

2- Filtering Unit I;

3- Filtering Unit II;

4- Resin tank;

5- Reagent tanks I;

6- Reagent tank II;

7- pH meter instrument;

8- C.E. Measuring instrument;

9- Dispenser, reagent tank I;

10- Dispenser, reagent tank II;

11- Water supply circuit.

In figure 2 it is possible to compare the same area of the reproduced point, where the image in the center is with the clean water and correct chemical values, in the left one the water is very acid which corrodes the point making it reduce in size. On the right side we have an image with an uncontrolled water that does not have the ideal cleaning capacity, so the point gets bigger.

Claims

1. Offset printer cleaning and chemical replacement system comprised of:

- A control unit with storage and data processing facilities configured to manage the operation of:

- At least one pneumatic water extraction pump;

- At least one cleaning block;

- At least one block of sensory instrumentation;

- At least one chemical replacement block.

System according to Claim 1, characterized in that the control unit is physically connected to the pneumatic pump and the sensory instrumentation and chemical replacement blocks.

System according to claim 1, characterized in that the control unit comprises a wireless communication module configured to communicate with the pneumatic pump and the sensory instrumentation and chemical replacement blocks.

System according to Claim 3, characterized in that the pneumatic pump and the sensory instrumentation and chemical replacement blocks have a wireless communication module configured to establish communication via wireless communication protocol with the control unit.

System according to Claim 1, characterized in that the cleaning block comprises at least two units. sequentially placed one after another.

System according to Claim 5, characterized in that a filtering unit has a filtering mesh whose mesh opening is greater than the mesh opening of the succeeding filtering unit.

System according to Claim 6, characterized in that the mesh opening is in the range of 5 to 25 microns.

System according to claim 1, characterized in that the sensory instrumentation block comprises at least one electronic pH measuring instrument and at least one electronic electrical conductivity measuring instrument, CE.

System according to Claim 1, characterized in that the chemical replacement block comprises at least one resin cell and at least two reagent tanks.

Method of operation of the offset press cleaning and chemical replacement system as claimed in any one of claims 1 to 9, characterized in that:

- comparison in the control unit of the values collected with those previously defined; - actuation of the control unit in the chemical replacement block, specifically in the resin cell and reagent tank feeders, if the collected values fall within the range of the defined values.

Method according to claim 10, characterized in that the operation period of the pneumatic pump is programmed by the user.

Method according to Claim 11, characterized in that the control unit is programmed to operate in three different operating modes, depending on the system hydraulic pressure and desired flow rates.