WO1999050076A1 - Printing solution for lithographic printing - Google Patents
Printing solution for lithographic printing Download PDFInfo
- Publication number
- WO1999050076A1 WO1999050076A1 PCT/IB1999/000551 IB9900551W WO9950076A1 WO 1999050076 A1 WO1999050076 A1 WO 1999050076A1 IB 9900551 W IB9900551 W IB 9900551W WO 9950076 A1 WO9950076 A1 WO 9950076A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- printing
- printing solution
- alcohol
- solution
- parts
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
- B41N3/00—Preparing for use and conserving printing surfaces
- B41N3/08—Damping; Neutralising or similar differentiation treatments for lithographic printing formes; Gumming or finishing solutions, fountain solutions, correction or deletion fluids, or on-press development
Definitions
- THIS invention relates to a printing solution for lithographic printing.
- planographic plates are used to transfer ink to a blanket roll, which, in turn, then transfers the ink to a substrate thereby forming printed images.
- the plates are referred to as planographic since the image and non-image areas are in the same plane.
- the plates are constructed so that with proper treatment the image areas are hydrophobic and oleophilic and thereby receptive to inks.
- the non-image areas are hydrophilic and are water receptive. In order to maintain the hydrophilic characteristics on the non-image areas, so as to prevent ink from accumulating on these areas, it is necessary continuously to treat the plate with a water based fountain solution.
- fountain solution is applied continuously to the printing plate just before the application of the printing ink.
- the fountain solution has an affinity for the non-image (hydrophilic) areas of the plate and wets these areas.
- a complete and uniform film of fountain solution on the non-image areas prevents the subsequent application of ink from covering the plate on the non-image areas.
- the fountain solution and ink on the plate are then both transferred to the blanket and then to the substrate. The process is then repeated.
- Lithographic printing plates are developed to expose metal surface in the non-image areas while image areas are left coated with a hydrophobic polymer.
- a developing system is disclosed in FR 2093585 for developing an exposed lithographic plate to remove non-image areas from plates of - 2
- the light-sensitive agent in the coating is a diazomium compound.
- fountain solutions which contain highly polar liquids which wet and coat the exposed metal surface of the non-image area of the plate.
- Plain water may perform reasonably well, although various aqueous electrolytes, surfactants and water soluble polymers are generally required for consistent performance.
- These additives promote plate wetting as well as controlling the interaction of the fountain solution with the ink and the substrate.
- isopropyl alcohol is often added to the fountain solution. This alcohol has the effect of lowering the surface tension of water in the solution which once again improves the efficacy of the solution.
- a printing solution for lithographic printing comprising a mixture of alcohol and a fountain solution, characterised in that inorganic constituents within the fountain solution are present in a concentration less than the saturation concentration of such inorganic constituents in water present in the printing solution.
- the alcohol typically comprises between 6 and 15 % by volume, preferably 10 % by volume, of the printing solution.
- the pH of the printing solution is between 4,0 and 5,9.
- the printing solution includes any one or more of the following: surfactants, corrosion inhibitors, collating agents, perfume, dyestuff, pigments and preservatives.
- the printing solution may include an acid which is added so as to maintain the pH between 4,0 and 5,9.
- the acid may be phosporic acid, acetic acid, boric acid or a combination thereof.
- acid salts or inorganic chemicals such as biosulphates and/or bisulphates, may be used to maintain the pH between 4,0 and 5,9.
- the alcohol is ethyl alcohol, propyl alcohol, isopropyl alcohol or a mixture thereof.
- a typical fountain solution comprises a fountain solution concentrate, water and an alcohol or alcohol substitute which are added to one another in a dosage system as is described above.
- the printing solution generally includes buffering salts, cleaners, corrosion inhibitors, collating agents and a surfactant (wetting agent).
- the printing solution which forms the subject of this invention comprises a mixture of fountain solution concentrate, water and an alcohol or alcohol substitute in which the inorganic constituents of the printing solution are present in a concentration less than the saturation concentration of such inorganics constituents within the water present in the printing solution.
- the printing solution is acidic and includes acidic components such as phosphoric, acetic, boric or citric acid so as to maintain a pH value between about 4,0 and 5,9 although neutral and basic printing solutions could also be used.
- the fountain solution is water based and is mixed with the alcohol and is not metered in separately.
- the fountain solution includes standard fountain solution constituents such as buffer salts, cleaners, corrosion inhibitors, collating agents and surfactants (wetting agents).
- concentration of the inorganic salts within the water of the fountain solution are adjusted such that they remain below their saturation concentration and thus do not precipitate out of the solution. Any precipitates out of the solution would interfere with the lithographic printing process.
- the pH and conductivity of the printing solution is adjusted to the desired range of pH4,0 to pH5,9 and 500 ⁇ S to 2000 ⁇ S. respectively.
- the alcohol may be isopropyl alcohol, ethyl alcohol, propyl alcohol, another suitable alcohol or a mixture thereof. It is preferable that the alcohol is present in the solution at a concentration of between 6 and 15 % by volume of the solution. The percentage is adjusted according to the specified press, speed, type of form and substrate being printed. Typically, the alcohol comprises 10 % by volume of the printing solution.
- the alcohol renders the printing solution more effective by lowering the surface tension of the water, thereby increasing the wetting action of the dampening solution. Also, it minimizes the fountain solution use while maintaining moisture on the plate surface. Reduced water pickup makes it easier for the pressman to maintain the correct ink/water balance. Furthermore, the rapid evaporation of the alcohol from the film of fountain solution on the blanket and printed sheet helps to minimize the sheet's tendency to curl.
- damper settings can be reduced by up to 25 % as compared to the two component dosage system. This in turn leads to brighter print colours and quicker ink drying.
- Another advantage of the printing solution according to the invention is inventory control where only one chemical is required to be stored instead of two (alcohol plus fountain solution).
Landscapes
- Printing Plates And Materials Therefor (AREA)
Abstract
This invention relates to a printing solution for lithographic printing. The printing solution comprises a mixture of alcohol and a fountain solution in which the inorganic constituents within the fountain solution are present in a concentration less than the saturation concentration of such inorganic constituents in water present in the printing solution.
Description
PRINTING SOLUTION FOR LITHOGRAPHIC PRINTING
BACKGROUND TO THE INVENTION
THIS invention relates to a printing solution for lithographic printing.
In an offset lithographic printing process planographic plates are used to transfer ink to a blanket roll, which, in turn, then transfers the ink to a substrate thereby forming printed images. The plates are referred to as planographic since the image and non-image areas are in the same plane. The plates are constructed so that with proper treatment the image areas are hydrophobic and oleophilic and thereby receptive to inks. The non-image areas are hydrophilic and are water receptive. In order to maintain the hydrophilic characteristics on the non-image areas, so as to prevent ink from accumulating on these areas, it is necessary continuously to treat the plate with a water based fountain solution.
While an offset printing press is running, fountain solution is applied continuously to the printing plate just before the application of the printing ink. The fountain solution has an affinity for the non-image (hydrophilic) areas of the plate and wets these areas. A complete and uniform film of fountain solution on the non-image areas prevents the subsequent application of ink from covering the plate on the non-image areas. The fountain solution and ink on the plate are then both transferred to the blanket and then to the substrate. The process is then repeated.
Lithographic printing plates are developed to expose metal surface in the non-image areas while image areas are left coated with a hydrophobic polymer. A developing system is disclosed in FR 2093585 for developing an exposed lithographic plate to remove non-image areas from plates of
- 2
which the light-sensitive agent in the coating is a diazomium compound.
There are many fountain solutions which contain highly polar liquids which wet and coat the exposed metal surface of the non-image area of the plate. Plain water may perform reasonably well, although various aqueous electrolytes, surfactants and water soluble polymers are generally required for consistent performance. These additives promote plate wetting as well as controlling the interaction of the fountain solution with the ink and the substrate. In addition, isopropyl alcohol is often added to the fountain solution. This alcohol has the effect of lowering the surface tension of water in the solution which once again improves the efficacy of the solution.
In introducing isopropyl alcohol into the fountain solution it is important to achieve the required concentration balance between the alcohol and the fountain solution. This is conventionally achieved by two dosage systems introducing the alcohol and fountain solution separately. A problem which exists with these dosage systems is that they require careful and experienced manual control or a sophisticated automatic control system.
SUMMARY OF THE INVENTION
According to the invention there is provided a printing solution for lithographic printing comprising a mixture of alcohol and a fountain solution, characterised in that inorganic constituents within the fountain solution are present in a concentration less than the saturation concentration of such inorganic constituents in water present in the printing solution.
3 -
The alcohol typically comprises between 6 and 15 % by volume, preferably 10 % by volume, of the printing solution.
Preferably the pH of the printing solution is between 4,0 and 5,9.
Typically, the printing solution includes any one or more of the following: surfactants, corrosion inhibitors, collating agents, perfume, dyestuff, pigments and preservatives.
The printing solution may include an acid which is added so as to maintain the pH between 4,0 and 5,9. The acid may be phosporic acid, acetic acid, boric acid or a combination thereof.
Alternatively, acid salts or inorganic chemicals, such as biosulphates and/or bisulphates, may be used to maintain the pH between 4,0 and 5,9.
Typically, the alcohol is ethyl alcohol, propyl alcohol, isopropyl alcohol or a mixture thereof.
Various embodiments of the invention are described in detail in the following passages of the specification. The described embodiments are merely illustrative of how the invention might be put into effect and should not be understood as limiting on the invention.
DESCRIPTION
A typical fountain solution comprises a fountain solution concentrate, water and an alcohol or alcohol substitute which are added to one another in a
dosage system as is described above. In addition, the printing solution generally includes buffering salts, cleaners, corrosion inhibitors, collating agents and a surfactant (wetting agent).
The printing solution which forms the subject of this invention comprises a mixture of fountain solution concentrate, water and an alcohol or alcohol substitute in which the inorganic constituents of the printing solution are present in a concentration less than the saturation concentration of such inorganics constituents within the water present in the printing solution. In general the printing solution is acidic and includes acidic components such as phosphoric, acetic, boric or citric acid so as to maintain a pH value between about 4,0 and 5,9 although neutral and basic printing solutions could also be used.
The fountain solution is water based and is mixed with the alcohol and is not metered in separately. The fountain solution includes standard fountain solution constituents such as buffer salts, cleaners, corrosion inhibitors, collating agents and surfactants (wetting agents). The concentration of the inorganic salts within the water of the fountain solution are adjusted such that they remain below their saturation concentration and thus do not precipitate out of the solution. Any precipitates out of the solution would interfere with the lithographic printing process. In addition the pH and conductivity of the printing solution is adjusted to the desired range of pH4,0 to pH5,9 and 500 μS to 2000 μS. respectively.
The alcohol may be isopropyl alcohol, ethyl alcohol, propyl alcohol, another suitable alcohol or a mixture thereof. It is preferable that the alcohol is present in the solution at a concentration of between 6 and 15 % by volume of the
solution. The percentage is adjusted according to the specified press, speed, type of form and substrate being printed. Typically, the alcohol comprises 10 % by volume of the printing solution.
Generally speaking, the alcohol renders the printing solution more effective by lowering the surface tension of the water, thereby increasing the wetting action of the dampening solution. Also, it minimizes the fountain solution use while maintaining moisture on the plate surface. Reduced water pickup makes it easier for the pressman to maintain the correct ink/water balance. Furthermore, the rapid evaporation of the alcohol from the film of fountain solution on the blanket and printed sheet helps to minimize the sheet's tendency to curl.
It has been found that by using a printing solution according to the invention instead of the previous two component dosage system, as is above in the background to the invention, the shapes of the printed dots are much sharper. The fuzzy edge given by the two component dosage systems is sharpened up due to the fact that the various chemicals dissolve in the mixture and reach the interface at the same time giving a clean edge to the printer material. In a two step system the chemicals are not always evenly dispersed and therefore do not reach the edge of the dot structure simultaneously, thus causing the fuzzy edge effect.
It has also been found that through use of the printing solution of this invention damper settings can be reduced by up to 25 % as compared to the two component dosage system. This in turn leads to brighter print colours and quicker ink drying.
- 6
Another advantage of the printing solution according to the invention is inventory control where only one chemical is required to be stored instead of two (alcohol plus fountain solution).
Examples of printing solutions according to the invention are the following formations:
Example 1
Isopropyl alcohol 45 parts
* Acticide AZ 0.2 parts
Sodium Citrate 0J parts
Sodium Hexametaphosphate 0.3 parts
Sodium Bisulphate 0.1 parts
Sodium Nitrate 0.4 parts
Citric Acid 0.4 parts
Waxoline Red OS 0.5 gramme
** Butyl Oxitol 10 parts
Water To 100 parts
Supplied by Thor Chemicals (South Africa)
** Supplied by Shell Chemicals (South Africa
Example 2
Alcohol (Ethyl, propyl or isopropyl mixtures of any two 60 parts or all three)
Potassium Dihydrogen Citrate 2.0 parts
Sodium Acid Phosphate 2.0 parts
Victoria Blue Dye 0.1 gramme
Magnesium Nitrate 0.4 parts
Water To 100 parts
Example 3
Propyl alcohol 82 parts
Formaldehyde 0.1 parts
* Acticide AZ 0.1 parts
Sodium Citrate 0J parts
Sodium Hexametaphosphate 0.2 parts
Sodium Bisulphate 0.1 parts
Sodium Nitrate 0.4 parts
Citric Acid 0.4 parts
Methylene Blue Dye 0.5 gramme
Water To 100 parts
Supplied by Thor Chemicals (South Africa)
Example 4
Propyl alcohol 19 parts
Isopropyl alcohol 20 parts
Perfume 0.2 parts
Tri-Sodium Citrate 1.6 parts
Citric Acid 0.4 parts
Sodium Nitrate 0.4 parts
Ethyl aniline phosphate 0.4 parts
Acticide AZ 0.4 parts
Water To 100 parts
Example 5
Alcohol (Ethyl, propyl or isopropyl) 50 parts
Boric Acid 2 parts
Sodium Bisulphate 0.2 parts
Sodiuim Hexametaphosphate 0.2 parts
Sodium Nitrate 0.4 parts
*** Surfanol FS 85 0.5 parts
*** Defoamer DX l lO 0.1 parts
Water To 100 parts
*** Supplied by Air Products, USA.
Example 6
Propyl Alcohol 76.0 parts
Secondary Butanol 6.0 parts
Aciticide AZ 0.1 part
Sodium Nitrate 0.4 parts
Sodium Acid phosphate 0.1 parts
Boric Acid 1.0 part
Celym 0.2 parts
Victoria Blue dye 0.2 grammes
Water 100 parts
Claims
1. A printing solution for lithographic printing comprising a mixture of alcohol and a fountain solution, characterised in that inorganic constituents within the fountain solution are present in a concentration less than the saturation concentration of such inorganic constituents in water present in the printing solution.
2. A printing solution according to claim 1, wherein the alcohol comprises between 6 and 15 % by volume of the printing solution.
3. A printing solution according to claim 1, wherein the alcohol comprises 10 % by volume of the printing solution.
4. A printing solution according to any one of the preceding claims, wherein the pH of the printing solution is between 4,0 and 5,9.
5. A printing solution according to any one of the preceding claims, wherein the printing solution includes any one or more of the following: surfactants, corrosion inhibitors, collating agents, perfume, dyestuff, pigment and preservatives.
6. A printing solution according to claim 4, wherein an acid is added to maintain the pH of the solution between 4,0 and 5,9.
7. A printing solution according to claim 6, wherein the acid is phosphoric acid, acetic acid, boric acid or a combination thereof. 11
8. A printing solution according to claim 4, wherein acidic salts or inorganic chemicals are used to maintain the pH between 4,0 and 5,9.
9. A printing solution according to claim 8, wherein the acidic salts or inorganic chemicals are biosulphates and/or bisulphates.
10. A printing solution according to any one of the preceding claims, wherein the alcohol is ethyl alcohol, propyl alcohol, isopropyl alcohol or a mixture thereof.
11. A printing solution substantially as herein described with reference to any one of the formulation examples 1 to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU29499/99A AU2949999A (en) | 1998-03-31 | 1999-03-31 | Printing solution for lithographic printing |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ZA982694 | 1998-03-31 | ||
| ZA98/2694 | 1998-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1999050076A1 true WO1999050076A1 (en) | 1999-10-07 |
Family
ID=25586922
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB1999/000551 WO1999050076A1 (en) | 1998-03-31 | 1999-03-31 | Printing solution for lithographic printing |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU2949999A (en) |
| WO (1) | WO1999050076A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103660668A (en) * | 2013-11-18 | 2014-03-26 | 蚌埠天光传感器有限公司 | Fountain solution with low-concentration ethyl alcohol and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3257941A (en) * | 1960-04-04 | 1966-06-28 | Anken Chemical And Film Corp | Method and means of making planographic printing plates |
| GB2008495A (en) * | 1977-11-16 | 1979-06-06 | Mitsubishi Paper Mills Ltd | Composition for treating lithographic printing plates |
| US4247328A (en) * | 1978-01-18 | 1981-01-27 | Vickers Limited | Lithographic fountain concentrates containing a desensitizing material in an organic solvent liquid |
| EP0112745A1 (en) * | 1982-11-26 | 1984-07-04 | INMONT S.A., Société anonyme dite: | Fountain solution composition for lithographic plates |
| US4563952A (en) * | 1983-12-21 | 1986-01-14 | Inmont Corporation | Lithographic water based fountain solution concentrates |
-
1999
- 1999-03-31 AU AU29499/99A patent/AU2949999A/en not_active Abandoned
- 1999-03-31 WO PCT/IB1999/000551 patent/WO1999050076A1/en active Search and Examination
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3257941A (en) * | 1960-04-04 | 1966-06-28 | Anken Chemical And Film Corp | Method and means of making planographic printing plates |
| GB2008495A (en) * | 1977-11-16 | 1979-06-06 | Mitsubishi Paper Mills Ltd | Composition for treating lithographic printing plates |
| US4247328A (en) * | 1978-01-18 | 1981-01-27 | Vickers Limited | Lithographic fountain concentrates containing a desensitizing material in an organic solvent liquid |
| EP0112745A1 (en) * | 1982-11-26 | 1984-07-04 | INMONT S.A., Société anonyme dite: | Fountain solution composition for lithographic plates |
| US4563952A (en) * | 1983-12-21 | 1986-01-14 | Inmont Corporation | Lithographic water based fountain solution concentrates |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103660668A (en) * | 2013-11-18 | 2014-03-26 | 蚌埠天光传感器有限公司 | Fountain solution with low-concentration ethyl alcohol and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2949999A (en) | 1999-10-18 |
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