The pigment lose from ink
Problem/Phenomenon
The ink dry completely,the pigment which can not combine with the ink were sticked off .
Possible Causes
1、The vehicle material of ink is saturate too well.
2、The hydroscopicity of paper is too well.
3、The drying of ink is delayed,the paper absorb too much of vehicle material before it solidifies.
4、The adhesiveness of vehicle was Over emulsification by the fountain solution ink.
Solution
Adding the vehicle material of ink ,reduce the saturate speed.
Change the paper.
Use the dry fast ink.
Recheck and confirm the foutain solution,PH,tack and content of alcoholicity.
Problem/Phenomenon
Ink stick on the non-image parts ,can not be erased and appear on the same station .
Possible Causes
1、There is fountain solution stick on the roller,and the surface of roller is dirty or dameged.
2、As the ink supply is too much,the ink spread on the round of dot and pollute the non-image parts.
3、The the pollution problem was not done well in the platemaking process.
4、There is pollution particle in the ink.
5、The imaging version was light leak in the platemaking process.
Solution
Clean the rubber with the scouring agent of which the platemaking supplier recommend.
Using the ink with high content of pigment,reduce the ink quantity.
Reprocessing the plate.
Change the ink with less pollution particle.
Change the plate.
Problem/Phenomenon
The ink on the roller can not be transferred evenly and appears the striping.
Possible Causes
1、The PH of Fountain Solution is too high.
2、There supply too much Fountain Solution .
3、The flow of ink is not good,over emulsification .
4、Emulsification quantity of ink is too small.
5、The pressure between the plate and rubber is high.
6、The content of Arabic gum in the fountain solution is too high.
Solution
Adjust the PH /US of fountain solution.
Reduce the supply of fountain solution.
Improve the flow of ink.
Improve the emulsiffication of ink.
Adjust the printing pressure .
Reduce the content of Arabic gum.
Rear Projection and Soakage
Problem/Phenomenon
The printing surface can be seen from the back of paper,vehicle infiltrate into the paper .
Possible Causes
1、The ink is supplied too much.
2、The ink contain too much of machine oil or the tack of machine oil is too low.
3、The oil absorption of paper is high,and the thickness is not enough or the transparency of paper is high.
Solution
Reduce the ink quantity .
Change the ink with high tack .
Change the paper.
Problem/Phenomenon
Such printing paper is separated from the blanket,tearing the surface of paper.
Possible Causes
1、The tack of ink is too high.
2、The tack of ink surface increase after the ink dry on the roller.
3、The strength of paper's surface is not good.
4、The adhesive force of coating film is too weak.
5、The printing pressure is too high,the rubber roller is too hard.
6、The temperature of printing workshop is too low and cause the tack of ink increase.
Solution
Add 5% of varnish into the ink to make the ink getting soft when printing.
Add 1-3% of diluent to ink to reduce the tack.
Change to use the paper with good strength .
Readjust the printing pressure.
Keep the ink cleaning.
Control the temperature of printing workshop.
Problem/Phenomenon
With time going by,the ink is not transfer to the roller from ink barrel.
Possible Causes
1、The flow of ink is slow,and the tack is not good and too hard.
2、The viscosity state of ink is changed.
3、It adds too much of pigment solvent and cause the flow of ink decline.
4、The fountain solution is too acidic,and supply too much.
5、The temperature of printing workshop is too low.
Solution
Add 1-5% of varnish into the ink.
Operate the ZGITATER in an ink barrel.
Mix the ink with a ink shovel as a first aid.
Adjust the fountain solution at the minimum.
Distribute an image area evenly onto the front side of paper.
Problem/Phenomenon
In multicolor printing process,the dots are printed by double upon printing.
Possible Causes
1、The tack of ink is excessive ,the tiny part of the paper are moved and cause the defocus.
2、The rollers is too old and cause the rough surface or the pressure is not good.
Solution
To add 12% of varnish into the ink to decrease the tack of ink.
Pls inspect the machine ,dealing with the poor part.
Problem/Phenomenon
As printing paper passes between blanket and roller,printed matters appears not clear.
Possible Causes
1、Most of the problem is caused by poor machine fixed and aging of machine.
Solution
Pls inspect the machine again to solve this problem.
Problem/Phenomenon
Printed mattersdestaining and glossness decreasing if exposed outside long time.
Possible Causes
1、The lightfastness of the pigments is bad.
2、There is the special chemical composition in the ink that causes fading.
Solution
Use the ink with good lightfastness.
Avoiding the moisture can improve the lightfastness.
Problem/Phenomenon
After printing, the printed matter are scathing by touching other things.
Possible Causes
1 、The content of abrasion resistance additive is not so much in the ink.
2、There add too much of varnish into the ink in the printing process.
Solution
Change the ink with good abrasion resistance.
Adding 1-5% of abrasion resistance additive in to the ink.
Printing the O.P. varnish on the coat of bad printed matters.
Problem/Phenomenon
Paper stack up on paper platform, due to slow dry of ink, ink spreadout or stick together.
Possible Causes
1. Ink has not enough drying agent.
2. Ink contain too much anti-oxidising agent.
3. Paper acidity too strong.
4. Paper too wet.
5. Solution has too stron acidity.
6. Drying agent in ink loss its function gradually.
Solution
Add suitable amount of drying agent to ink.
Add drying agent and good drying power of linking material.
Before printing, test the dryness of paper first.
Use hot wind blower or keep paper store in a dry place before printing.
Good ventilation is helpful to drying of ink.
Adjust the PH value of solution to over 4.
Add drying agent to ink to replenish loss function of drying agent.
Problem/Phenomenon
full plate portion or shade portion printing effect not even and have mottling.
Possible Causes
1. Ink bad absorbing power.
2. Paper not even.
3. Printing pressure not consistant.
Solution
Add extra resin (agent that increase viscosity) or 1 to 5% of gloss pigment solvent.
Keep solution drun clean and adjust PH value between 5.5 to 6.5, and use less solution to a minimum.
Use re-adjusted printing pressure.
Use less solution.
Problem/Phenomenon
Ink loss fluidity, so printing matter after drying cause serious loss of gloss.
Possible Causes
1. ink not enough disperse, bad particle.
2. ink flow low, bad viscosity and bad water resist.
3.too much supply of solution, strong acidity.
4. paper too powdery, paper film too weak causing some tissue detached and mix with ink.
5. too much IPA added to solution.
Solution
Use ink without adding any auxiliary agent.
If having same trouble for long time after checking the initial cause of paper and printing reason,changin new ink immediately.
Reduce supply of solution and re-adjust acidity level.
Konfirm the powdery condition of paper to find method to reduce powder in paper.
Keep solution drum clean and check the quantity of IPA added.
Unclean fountain solution
Problem/Phenomenon
Non picture section all contaminated by light color
Possible Causes
1. ink very soft.
2. pigment in ink has poor water resistance.
3. too much of ink adjusting agent or other additive added.
4. the chemical ingredient in paper over absorbed by fountain solution.
5. the paper powder in paper all dispersed by fountain solution.
Solution
Under the circumstance ink concentration not reduced, add high viscosity resin.
Use new ink to replace part of ink.
Reconfirm the pressure of color roller pressure.
If fountain solution is too acid, adjust PH value between 5 to 6, and partly replace with new ink.
Keep drum of fountain solution and water roller clean.
Problem/Phenomenon
Dot or plate surface not even, white portion or small letter portion is filled or augmented.
Possible Causes
1. ink over emulsified, low tack value.
2. dilution agent in ink or too much printing resin being added.
3. powder of paper surface being dissolved and mix with ink.
4. acidity of solution too strong, IPA content too high.
5. too much supply of solution makes ink being emulsified.
Solution
Add 5% resin oil of high viscosity to increae tack value of ink.
Use less solution and increase 5-10% IPA.
If this happen in long period of printing, can be solved by adding 50% new ink during printing.
Re-adjust solution.
Clean powder on paper and avoid dust to enter printing room.
Problem/Phenomenon
During printing, non picture portion partly stick to the ink and picture of former portion
Possible Causes
1. ink has low viscosity.
2. ink has too much drying agent added, and dilution agent or resin oil content too much.
3. paper has too much powder and the surface PH value too high.
4. the function of solution is weaken when the chemical on paper is dissolved by solution.
5. printing plate not smooth and part of it is acidified.
6. color printing roller has bad setting.
7. solution or solution drum not clean.
Solution
Use resin oil with higher tack to increase higher tack value of ink.
Change new ink when auxilliary agent content is high.
If no auxilliary agent is not used, when use ink too long, need to replace new ink to improve.
Clean solution drum and re-adjust PH value of solution.
Reconfirm the setting of color printing roller.
Confirm printing plate, if not smooth or acidified,
Replace new plate.
Problem/Phenomenon
such dots become large by long-hour printing,decreasing the contrast of printed matters
Possible Causes
1、Inappropriate pressure setting of rubber roller and printing cylinder.
2、Rubber roller and blanket too soft.
3、Inappropriate setting of blanket mounting or too high pressure.
4、Piling.
5、Fountain solution system too dirty.
6、Not balance of PH value or conductivity of fountain solution.
7、Ghosting appears in some half tone portion.
Solution
Reset the pressure of rubber roller and printing cylinder.
Adjust or replace rubber roller and blanket.
Check the blanket mounting and pressure.
Please refer to the guide in piling.
Clean the fountain solution system.
Set the proper PH value or conductivity as suggested by maker.
Check the cylinder pressure,blanket and the machanical operation of printing machine.
Problem/Phenomenon
Possible Causes
1、Inadequate use of adhesive material in ink.
2、Low tack value of ink.
3、Bad absorbing of paper.
4、Slow drying of ink.
Solution
Use ink with weaker color density and with faster drying.
Use ink with higher tack value.
Use ink with weaker color density and with faster drying.
Add appropriate quantity of drying agent.
Problem/Phenomenon
The printing image part on the backside trans to the front of paper,appears virtual image
Possible Causes
1、Bad quality of paper and use ink with
fast dry property.When oxidising ,ink emits gas that is trapped in
paper,spreeding the drying on that part and so induce lack of gloss and
weak shadow effect.
Solution
Change using other type of paper or apply O.P.varnish after printing. Blow air oftenly to the paper.
Problem/Phenomenon
The back of paper onside was setted off by the ink on underside paper
Possible Causes
1、Inadequate spray powder
2、Paper stack too high at paper receiving end.
3、Ink supply increase due to weak color density of ink.
Solution
Use more spray powder and use larger particle of spray powder.
Avoid paper stacking too high.
Use ink with higher color density to avoid the need to increase ink supply.
Problem/Phenomenon
The color were shallowed along with the anilox roller can not transfer the ink completely
Possible Causes
1、Short ink thread and lack of flow.
2、Ink has thixotropy feature,must stir to avoid becaome solid.
Solution
Add good quantity of ink recucer to increase the flow.
Stir often so that ink stays fowing.
Problem/Phenomenon
color penetrate
Possible Causes
1.Wrong PH value or conductivity of fountain solution.
2.Hardness of rubber roller not suitable or set wrongly.
3.Cleaning agent has been used for too long time.
4.Too big pressure between plate roller cylinder and blanket cylinder.
5.Fountain solution is contaminated by coating on paper and ink.
6.Printing plate has not been properly exposed and developed.
7.Cleaning agent is found in fountain solution.
8.Fountain solution too high temperature or moving roller temperature too high.
Solution
Adjust the PH value or conductivity according to factory's specification. Discuss with your fountain solution supplier.
Must clean thoroughly after using cleaning agent, and then clean with hot water.
Check and adjust the proper pressure.
Use ink with least adhesion when possible. Use the least printing pressure and suitable fountain solution.
Discuss with your plate making department.
Remove cleaning agent.
Adjust to the temperature suggested by maker.
Problem/Phenomenon
Possible Causes
1.Most ofter is caused by slipping of roller cylinder or printing machine.
2.Oil on roller cylinder. Not suitable mounting of roller cylinder (too thick or too thin). The gear that pick up
3.Blanket is too sticky or not mounted properly.
4.Ink is too hard or has too high tack value.
Solution
Adjust and correct the printing condition.
Check printing condition.
Use suitable blanket.
Use softer kind of ink.
Problem/Phenomenon
Oil penetrate
Possible Causes
1、Not suitable hardness of ink roller (too soft or too hard).
2、Ink roller or water roller set too tight.
3、Blanket mounting too thick or not tight.
4、The oil-based cleaning agent has been used for too long.
5、Printing plate is not properly exposed.
6、Not suitably use of fountain solution.
7、Dampening system not well maintained.
8、The composition and formulation of fountain solution not match with ink.
9、Too thick ink film.Blanket crystallised.
Solution
Check hardness of ink roller, set it correctly and observe the condition of use etc.
Check and reset the setting of ink roller and water roller.
Adjust the mounting of blanket and remount it with more tight.
Change new cleaning agent.
Discuss with your plate making department.
Adjust PH value and conductivity of fountain solution.
Properly maintain dampening system. Clean and upkeep fountain solution water duct and value.
Discuss with your fountain solution supplier.
Change to use ink with higher color density.Remove the glossy surface or replace blanket.
Scratch or rubbing on printing plate
Problem/Phenomenon
The image of printing plate is imperfect ,the printing plate is abraded
Possible Causes
1、Improper develop of printing plate.
2、Dampening system being contaminated by surface active agent.
3、Use unsuitable fountain solution or formulation.
4、Plate is not cleaned after apply plate cleaner.
5、In the process of printing, fiber, coating or lint continuingly generated onto blanket and make printing plate damaged.
6、Improper setting of ink roller or water roller make plate damaged.
7、Mounting of blanket too loose or too tight.
8、Instrusion of alien material to the ink trander roller.
9、The dot of picture/letter loses
because plate surface or blanket has captured some substance that do not
attract to ink around.
Solution
Recheck the processing craft of plate developing.
Make sure all working part of
dampening system that is in contact with surface active agent are
properly cleaned when install to printing machine. Strictly use and
moniter the proper cleaning agent.
Check PH value and conductivity value. Discuss with your fountain solution supplier.
Do not apply excessive plate cleaner.
It must be thoroughly cleaned after applying. All material, include
water, sponge or cleaning towel that has been in contact with plate must
be cleaned. Do not let plate cleaner drip dry on surface of plate.
Check PH value and conductivity of fountain solution. Seek paper supplier for solution.
Check ink roller and water roller setting condition and operation situation.
Check the tightness of mounting of blanket according to maker's requirement.
Check paper, ink and all cleaning agents. Avoid alien substance falling into the printing machine.
Use better lubricated ink. Increase cleaning frequency of blanket. Discuss with your fountain solution supplier.
Problem/Phenomenon
There are bright speck and macula becoming the rough parts on the printed matter.
Possible Causes
1.Too much water supply, excessive emulsification of ink.
2.The former set of rolling cylinder has excessive water supply leading to paper tranfer with excessive water.
3.Paper not strong or coating too weak.
4.Blanket rolling cylinder has too much pressure on paper.
5.Blanket too hard.
6.Too high color density of ink leading to inadequate supply of ink being transferred to plate.
Solution
Reduce water supply. Adjust water/ink balance.
Reduce water supply of former set of roller cylinder.
Use suitable quantity of tack reducing agent to decrease tack of ink.
Reduce printing pressure to machine supplier's specification.
Change to blanket with softer nature.
Add ink reducer to reduce color density of ink.
Problem/Phenomenon
Ink or paper dust,damaging a blanket roller if used for long time.
Possible Causes
1、Ink emulsified pigment to separate due to decrease in viscosity or tack value.
2、Inappropriate hardness of rubber roller,inappropriate setting.Inadequate mounting of blanket or inappropriate setting
3、The surface temperature of ink transfer roller not correct.
Solution
Reduce quantity of fountain solution. Check property of emulsification of ink.
Use suitable rubber roller and blanket. Check the operation setting of
rubber roller, mounting of blanket etc. and conduct cleaning or
adjustment when necessary.
Adjust temperature of ink roller to its sugested temperature and check the setting.
Problem/Phenomenon
Fine ink particles spread and float in air after ink distributes and passes between rollers.
Possible Causes
1.Over-supply of ink in order to increase color density of ink.
2.Ink roller damaged or improper setting.
3.Ink transfer roller has been affected by static electric.
4.Water/ink not balance.
5.Printing machine too high temperature.
6.Ink sprinkle to underneath.
Solution
Change to ink with higher color density and print with thinner layer of ink.
Check if ink film has been damaged or not, and also check if the ink roller is set properly.
Check if the printing machine is properly grounded.
Adjust water/ink to a balance level.
Check the cooling system of ink roller. Check fountain solution (alcohol, temperature).
Adjust water and ink balance. Use solid color strip to absorb excessive ink.
Problem/Phenomenon
When printing,ink is not printed to its appropriate position due to extemal factors.
Possible Causes
1、The surface of ink roller is already glossy and smooth or covered by incoming substance.
2、The PH value and conductivity of fountain solution is too acidic.
3、The stainless steel roller or copper roller has become wet and thus repels ink.
4、Too high color density of ink.
Solution
Wash and clean ink roller with suitable solvent and hot water.
Check the PH and conductivity values
of fountain solution and adjust it to the specific value of maker. Use
suitable cleaning agent to wash ink roller. Discuss with your fountain
solution maker.
A)Replating of copper roller. B)Clear
the covering substance on stainless steel roller, then re-apply ink
after thoroughly dried.
Reduce color density of ink and increase ink supply.
Problem/Phenomenon
Possible Causes
1. ink surface dring too fast.
2. ink has ink skin, dust and paper tissue mixed.
3. paper not properly kept, has adulterant.
4. printing work shop not clean.
5. overuse of powder spraying equipment.
Solution
Add 5% of ink reducer to the ink to reduce it drying speed.
Add 0.5 to 1% of anti-drying agent to the ink on color roller.
Before using paper, try to remove paper powder and tissue from paper.
Keep printing work shop clean.
During printing, use less powder spraying equnipment.
Problem/Phenomenon
When polychrome printing,the ink can not printed on the preceding ink film clearly.
Possible Causes
1、Tack value of ink not in correct printing order.
2、Color density of 4 process color
not in concord. First print color has high density, and susequent color
has low density. So there is difficulty in overprinting.
3、Water/ink not good balance.
4、Ink that print first has thick ink
film. If possible, the one that print first should not have thick layer
of ink than the one print later.
Solution
Confirm the decrease of tack value of
ink according to printing order. But sometimes when print in the order
of cyan-magenat-yellow, the lower tack value of black ink can reduce
lint in paper.
If ink has high color density and thick layer, then it is necessary to reduce color density of ink.
Adjust water/ink balance and keep it stable. Use less water and ink.
Suitably increase the density of ink
so that ink film is thinner. But be careful if handle improperly would
result in imbalance of color.
Problem/Phenomenon
Possible Causes
1.Too much tack value of ink to paper.
2.Inadequate property of anti-lint of paper.
3.Printing pressure not correctly set.
4.Water/ink not balance.
5.Too much tack value of blanket.
6.Inproper mounting of blanket.
7.Too high viscosity of ink and so causing ink layer to become thin.
8.Too low temperature.
Solution
Change to use ink with less tack value or add 1-2% of tack reducing agent.
Change to other paper. Discuss with your paper supplier. Install brush or dust remover.
Set printing pressure as per suggestion of machine maker.
Adjust water/ink to a balance level.
Clean the surface of blanket to
reduce tackness. Use blanket with quick strip property. Check the
cleaning agent of blanket. Solitcit solution from blanket supplier.
Make correction to the mounting of blanket (too much mounting or inadequate mounting can cause crystallisation.).
Change to ink with smaller tack value.
Adjust temperature of printing room and fountain solution. Preheat printing machine before printing.
Problem/Phenomenon
Possible Causes
1、Too much supply of ink. The set time of ink on paper is too slow.
2、Bad absorbing power of paper. Slow penetration of solvent is too slow.
3、Not suitable setting of spray powder--either insufficient or not evenly spread.
4、Paper stack too high.
5、Improper operation when moving paper. Paper blocking board not properly set.
Solution
Use hot air blower to speed up set time. Discuss with your sales representative.
Use more spray powder.
Check printed paper under Lansco
lamp. Check whether powder on paper is evenly spreaded or not. Adjust
powder supply system when necessary.
Avoid paper stack too high or increase quantity of spray powder.
Properly operate when moving paper. Re-adjust the blocking paper board.