In 1994 direct image system for photopolymer plate was first introduced, the industry has welcomed this new technology until now. It is however, tremendously expensive equipment investment and 30% higher cost of a digital plate than a conventional photopolymer plate are the reasons not able to be accepted by a plate maker or a printer widely.
Meantime, due to creative development of inkjet technology, spray an image on a non treated or coated film in detailed and fine image is very easy to achieve nowadays, so that to print a negative image on any of photopolymer plate by means of a flat bed inkjet printer no mater it is a flexographic or letterpress plate is no longer difficult to print a fine image on the plate directly any more. The printer is easy to get from the market now at reasonable price and the negative image can be reproduced sharply direct on a flexo plate.
This article will indicate non negative film plate making by direct inkjet image on a photopolymer plate deeply in order to compare with conventional way of plate making and digital plate with black layer coated to make image by means of an expensive laser ablation machine.
Conventional flexo plate making
From a conventional way of plate making, these are the normal procedures : back exposure → film exposure → washout → drying → anti-tack → post exposure.
Back exposure is to determine the thickness of a relief base in order to support a finished plate for long run by means of a short exposure on the back of a plate before having an image exposure with a negative film.
Film exposure is to give the plate an original image from a negative film in order for printing with design, photopolymer plate hence exposed by UVA light to harden the image area while the unhardened part is washout by the solution no mater it is a solvent washout or water washout plate, a relief plate will be ready for printing after drying and anti-tack procedure. Drying is to remove the solution completely from inside a plate during washout which is penetrated into plate, after drying the plate goes back the original thickness and good for printing. By using UVC lamps, it is a dry and easy way to remove the tack of a processed plate if in the past time have to use bleach + hydrochloric acid to achieve this function by which a pollution odor of chlorine is produced and it hurts human respiratory organs a lot.
Laser ablation image on digital plate
This is so called the pioneer of CTP, (Computer To Plate) which is using a black layer coated photopolymer plate by using laser ablation removing the layer according to image then naked photopolymer areas are waiting for UVA exposure to harden and to form printing relief after washout. Photopolymer is not sensitive to this ultra red light wave at all therefore it is no affection to the plate during UVA exposure afterwards. The digital plate is now as a plate + negative film on it, after expose to UVA lamps entirely, it is completely the same as a conventional plate with negative film exposure already now, the following procedures are the same as conventional plate making. Black layer is easy to be washout with the solution inside the washout tank automatically without any problem, but the film exposure with vacuum pump for close contact without air bubbles in between film and plate is deleted.
Direct inkjet image new technology
Due to progressing nozzle technology day by day, its easy to inkjet black image with density over 3.50 on any non-coated or non-treated film as a negative for plate exposure. For this sake, it is also easy to inkjet image on photopolymer plate directly as CTP (Computer To Plate) and vacuum pump is no longer required. Most important is that expensive invest of equipment and do not have to 30%+ cost for the digital anymore by just purchasing an inkjet printer from market and using conventional plate can achieve the CTP process from now on.
A new selection of flexo plate making for corrugated box printing industry with this creative CTP technology is available and in practical use now in addition to ESKO and CREO, this is due to contemporary development of Inkjet printer. Users do not have to buy extremely expensive laser ablation machine or image setter any more in order to save investing cost by using inkjet printer from the market in stead. This new method of flexo plate making is opening a new era of flexo plate making from these following reasons:
1. You do not have to use photographic film, this will save you not only processing equipment but also expensive photo film, chemicals of developing the film and electricity to maintain the processor… Now the new way of CTP direct image to plate from an inkjet printer is costing you only USD 0.70 per square meter while from the conventional way of film cost from an image setter by using photographic film is costing you at least USD 4.00 /m2 if ignoring the expensive equipment costs.
2. Laser ablation machine from ESKO or CREO priced at least USD 200,000-400,000 is too expensive and as a magic figure for corrugated industry, while an image setter is also cost too much if compare with a print out from inkjet printer. If you are using a second hand image setter which is retired from offset industry is now also the time to rebuild or repurchase which means that you have to pay for the expensive spare parts and expenses of maintaining the equipment despite of the high cost of photo film which is fading out from market. CTP inkjet from NozzleBlack is your best choice now.
3. CTP system from NozzleBlack can print your image on any thickness of photopolymer plate by any brand. It also can print on all kind of uncoated and untreated film like PET, OPP or PVC. This is a good news for liquid photopolymer plate makers who do not have to use the thin OPP film any more as a protecting film from resin to negative film. Due to inkjet nano ink technology you can print your image direct to the protecting film with direct contact to photopolymer with a Zero distance contact to reproduce a completely sharp image now and the OPP film does not have to be so thin by which may disturb you during plate making a lot .
4.NB-nano black ink is a another new development by which enable to print higher opaque density black ink on the plate due to nano 20 technology density now can increase over 3.50, which is good for longest exposure time required 7mm photopolymer plate exposure for corrugated printing. Also because of nano technology the ink layer is very hard and not easy to scratch and with no pin hole on solid black area as well as it is less opportunity to block the printer nozzles.
5.After inkjet, the black ink is hardened and dry, the image is sharp will not spread and inflate so it is good for proceeding UV exposure but it is easy to be solved out during washout process without any residue, after this, plate drying and anti tack treatment procedures are the same with the conventional plate making until to finish a plate.
6. Due to direct image on plate, therefore do not have to use vacuum pump any more, the always happened problem of air bubble involved in between the plate and negative film is avoided which was a major reason why can not make a good plate for printing. From now on the plate making can be 100% successful and save you 10-20 minute process time and labor from accessing the vacuum procedure on the machine.
7.Round shape dots in 45 degree is printed clearly dot by dot and reproduction up to 60 LPI which is good enough for screen printing and corrugated plate making. This is a most economic and convenient way with 100% successful job to inkjet direct image on plate now, by using this new CTP system, you do not have to hire a skilled engineer with high pay.
8. Existing softwares for your graphic design can be kept on using, our RIP soft ware is enable you to make fine dot for continuous tone printing which is no difference with a dot done by photographic film. From the RIP software, gradations and flat screen areas can be also reproduced as good as from an image setter.
Conclusions summarized as following for easy understanding :
A. Photographic film is no longer required, computer image can be printed direct on any photopolymer plate
B. NozzleBlack inkjet printer is costing you as common as a printer from market, which is saving you lots of investment and to use expensive black-coated digital plate.
C. No need to use vacuum unit any more, no more contact problem in between negative film and plate so it is easy to make a good plate with 100% success.
D. @flexo CTP system simplified the plate making procedure for easy access and saving 10-20 minutes process time. Skillful engineer for plate making is no longer required.
