The PS plate used in printing, short for "Presensitized Plate," plays a central role in lithographic printing. PS plates primarily use aluminum as their base. Aluminum is a metal with a lightweight, relatively strong, and stable metal structure, making it an ideal base for PS plates.
The aluminum plate's surface undergoes special treatments, such as electrolysis and anodization, to form a thin film of aluminum oxide. This film forms the hydrophilic portion of the PS plate, approximately 0.2-1μm above the plate's surface. Its hydrophilicity, wear resistance, and chemical stability significantly contribute to improving the plate's print run rate.
The aluminum plate surface is also coated with a photosensitive layer, primarily composed of diazo compounds. Diazo compounds undergo a specific reaction under the influence of light, which is key to the image and text transfer capabilities of PS plates.
The diazo photosensitive resin forms the oleophilic portion of the PS plate, approximately 3μm above the printing base. It allows ink to spread well while effectively preventing water from spreading, creating an excellent oleophilic-hydrophobic film.
Furthermore, the diazo photosensitive resin exhibits excellent abrasion and acid resistance. By baking the PS plate at 230-240°C for 5-8 minutes to enamelize the photosensitive film, the plate's hardness is further enhanced, enabling a print run of 200,000-300,000 sheets.
PS plates are primarily categorized as positive and negative. Of these two types, positive PS plates are more popular. Haomei Aluminum, positive ps plate factory, tells you why it is so popular:
Compatible with Modern Printing Processes: Currently, positive ps plates are more commonly used in the printing industry. In practice, when developing positive PS plate, the diazo compound in the image area remains on the plate, while the diazo compound in the non-image area decomposes and is removed by the developer. This imaging method integrates seamlessly with modern printing processes, making the entire printing process smoother and more efficient.
Excellent Dot Reproduction: Dot reproduction is crucial for high-quality prints. Positive PS plates are excellent in this regard, accurately reproducing the image's dots, resulting in rich layers, crisp details, and excellent tonal reproduction, meeting the stringent quality requirements of the high-end printing market. Whether it's exquisite albums and magazines, or art prints demanding exquisite color and detail, positive PS plates ensure high-quality prints.
Wide Development Latitude: The development stage is crucial in the printing process. Positive PS plates offer a wide development latitude. This means that even with fluctuations in parameters such as development time and temperature, they maintain excellent development results, preventing issues like dot loss and plate smudging. This significantly reduces scrap caused by improper operation, improves production efficiency, and reduces costs. This feature is particularly important for large-scale printing, ensuring stable and consistent print quality.
High Resolution: As the market demands for increasingly high precision in printed products, the resolution of PS plates has become a crucial indicator. Positive PS plates offer high resolution, enabling clear rendering of detailed images and text. This provides significant advantages when printing fine lines, small text, and complex patterns. This enables them to meet the demands of high-resolution printing applications such as label printing and anti-counterfeiting printing, further expanding their application range.
Haomei Aluminum is one of the big aluminium printing plates manufacturers. Welcome to inquire PS/CTP plate price from us.