Teach you to use photosensitive CTP plate
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
With the wide application of computer technology in the printing industry, CTP technology has gradually gained the attention of printing companies. For CTP technology, the quality and application of CTP plates is the key to ensuring plate quality.
After more than ten years of development, CTP technology has gradually formed three major categories: thermal CTP plate, silver salt CTP plate and photosensitive CTP plate. Each type of CTP plate has its own different characteristics and scope of application. Among them, the thermal CTP plate material has almost monopolized the commercial printing market with the advantages of high resolution, high printing durability and bright room operation; since the listing, the silver salt CTP plate has been dominated by the newspaper printing field with high speed, but In recent years, it has been affected by photosensitive CTP plates, and its development prospects are bleak; the performance of photosensitive CTP plates is between the former two, which can be used for both newspaper printing and commercial printing, with broad prospects.
Main features of photosensitive CTP plate
At present, the photosensitive CTP plate and the matching purple laser diode CTP platesetter are considered to be the most promising technologies in the CTP field.
Among them, the main features of the photosensitive CTP plate include: purple laser wavelength is shorter (405nm), which can form sharp and precise dots; low cost, no additional steps for the processing of the plate, the cost of the process is low; the operator uses Yellow safety light can be more convenient; high chemical resistance, normal use of cleaning paste, dampening solution, ink cleaning agent and other printing accessories; plate making speed is fast, mainly because photosensitive CTP plate is more than thermal CTP plate The material is more sensitive.
Tips for using photosensitive CTP plates
Photosensitive CTP plates vary in performance depending on the manufacturer. A set of corresponding exposure parameters and development processing conditions should be developed for the performance and characteristics of different brands and models. Due to the short launch time of photosensitive CTP plates and matching plate-making equipment, related operation techniques have yet to be improved. Therefore, we need to pay more attention to the storage and troubleshooting of photosensitive CTP plates.
1. Storage of photosensitive CTP plate
When storing photosensitive CTP plates, they should be placed in a special outer packaging cardboard box and placed in a cool, dry and dark place, not near the window. If stacked vertically, the photosensitive CTP plates can be stacked vertically on the stacking table or stacked against the wall to avoid curling. If it is required to be stacked horizontally, it can be stacked in a package without any protrusion. Up to 30 packages of photosensitive CTP plate of the same size can be stacked. Handle it gently during storage to prevent damage to the plate due to excessive vibration. .
2. Troubleshooting steps
Photosensitive CTP plates must be resolved in time during the plate making process, but there are many reasons for the failure. Therefore, the processing steps are the key.
I recommend that you first check the exposure conditions, specifically check whether the resolution is correct and whether the laser output power is correct. Recalibrate the laser output power if necessary.
Then check the media to see if other media have similar quality issues in the same batch.
If it is determined that it is not a problem with the plate, check the processor again to see if the pH is within the required range, if the developer temperature and development speed are correct, and if necessary, replace the developer with a new one.
3. Common faults and troubleshooting methods
(1) Fault phenomenon: the spot at the highlight is lost
The main reasons and solutions are as follows.
1 exposure reason
Underexposed: Check the exposure settings, including checking that the calibration laser output and exposure parameter settings are correct, using the correct exposure parameters.
Incorrect halftone correction: Recalibrate the linearization curve and the print compensation curve.
The laser is not focused: the focus should be readjusted.
2 development reasons
The developer dilution rate is incorrect: use the correct dilution rate and add the appropriate amount of developer.
The developer temperature is too high: it should be checked and adjusted to the normal developer temperature range, ie 28 °C ± 2 °C.
Development time is too long: adjust to the correct development time.
Preheating temperature is too low: adjust to the correct preheating temperature, ie 90 °C ± 10 °C
(2) Fault phenomenon: dot enlargement (paste), residual film in non-image area
The main reasons and solutions are as follows.
1 exposure reason
Overexposure: Excessive exposure can cause dot gain, and even photopolymerization of the non-image area will occur, so the correct exposure should be used.
Optical instruments have dirty spots: optical instruments and lenses should be cleaned.
The laser is not focused: the focus should be readjusted.
2 development reasons
The dilution rate of the developer is incorrect: the correct amount of developer should be added with the correct dilution rate.
Developer Fatigue: Replace the developer with a new one in time, reset the correct replenishment conditions, and accurately add the replenishing developer.
Developer temperature is too low: should be checked and adjusted to the normal developer temperature range, ie 28 °C ± 2 °C.
Insufficient water washing: Check whether the nozzle is blocked, and clean the blocked nozzle in time; check whether the amount of water sprayed by the nozzle is appropriate. If the water volume is not suitable, adjust the water pressure to control the water volume.
The brush roller pressure is incorrect: the pressure between the brush roller and the plate should be adjusted or the water lint should be replaced.
The preheating temperature is not correct: the preheating temperature should be adjusted. The front preheating temperature of the photosensitive CTP plate can be measured by attaching a temperature sticker on the back of the CTP plate. The preheating temperature should be 90 °C ± 10 °C.
(3) Fault phenomenon: the dot becomes smaller and the printing durability is lowered.
The main reasons and solutions are as follows.
1 exposure reason
Underexposed: Check the exposure settings, including checking that the calibration laser output and exposure parameter settings are correct, using the correct exposure parameters.
Small dot calibration is incorrect: calibration should be performed again.
The laser is not focused: the focus should be readjusted.
2 development reasons
The developer dilution rate is incorrect: use the correct dilution rate and add the appropriate amount of developer.
The developer temperature is too high: it should be checked and adjusted to the normal developer temperature.
Development time is too long: adjust to the correct development time.
Preheating temperature is too low: Adjust to the correct preheating temperature.
3 printing reasons
The printing pressure is too high: the printing pressure is set correctly.
The pH of the dampening solution is low: adjust the pH of the dampening solution to 4.0 to 6.0.