Printing System 1
Types of Printing Technologies
Conventional Printing (with master): Requires a printing plate
Examples:
Lithography (Offset)
Gravure
Letterpress
Screen Printing
Non-Impact Printing (NIP technologies): Does not require a printing plate
Examples:
Electrophotography
Inkjet
Printing Process Involvement
All printing technologies focus on transferring information to a substrate (paper, web form).
The process involves three main phases: Prepress, Press, and Postpress.
Each phase requires specific preparations and finishing to create the final printed product.
Conventional Printing Technologies (with Master)
Functionality of Printing Plates
A printing plate is vital for transferring ink to the medium, generating printed images through ink transfer and screening.
Screening involves breaking up originals into dots to create tonal variations (halftones) necessary for printing.
Key Features of Conventional Printing
Operates in a binary system (ink transfer or no ink transfer).
Requires careful management of ink levels and distributions through the printing process.
Non-Impact Printing Technologies (NIP)
These technologies allow for dynamically different printed pages without the need for a stable, physical image carrier.
Significant for personalized printing jobs (e.g., mailings).
Full digital description of the printed product is essential for production.
Important Terms in Printing Technology
Printing: Process of applying ink to a substrate to convey information repeatably.
Printing Plate: Medium for ink transfer; capable of multiple reproductions.
Printing Substrate: The material receiving the ink (e.g., paper).
Printing Press: The machinery used to perform printing processes.
Printing Systems Overview
Techniques
Letterpress (Relief) Printing:
Mechanism: Raised elements transfer ink under pressure to the substrate.
Materials: Traditional use of hard metal plates and soft rubber or plastic in flexography.
Gravure Printing:
Mechanism: Recessed elements hold ink; a doctor blade removes excess ink.
Applications: Used in high-volume color printing and specialized areas (like security).
Lithography:
Mechanism: Planographic technique; uses a combination of ink-repellent and ink-absorbing surfaces.
Modern use: Mainly offset printing, an indirect process with a rubber blanket.
Screen Printing:
Mechanism: Ink is pushed through a fine mesh stencil onto the substrate.
System Innovations
Backpressure Elements: Required in all printing technologies to ensure proper contact for ink transfer.
Production speeds have increased significantly—modern techniques can achieve 5000 to 100000 impressions per hour.
Prepress Operations
Importance of Prepress
Prepress is essential for transforming a creative vision into a physical print, ensuring all elements are correct before the main printing process.
Stages include pre-flighting, Raster Image Processing, and proof creation.
Stages in Prepress
Pre-Flighting:
Process of checking files for issues that might hinder quality before printing.
Raster Image Processor (RIP):
Converts digital files into formats suitable for printing.
Proof Creation:
Sharing soft (digital) and hard (physical) proofs with clients for approval.
Creation of Printing Plates (for Offset):
Final step for projects meant for offset presses.
Letterpress Printing Process
Mechanism: Uses raised letters that are inked and pressed onto paper.
Applications
Common in printing books, switch to flexographic solutions, while retaining vintage aesthetic for desired projects.
High setup times limit use, pushing many towards quicker offset options.
Print Cylinder Functionality
Precise alignment between inking rollers and substrates is vital for quality.
Advantages and Disadvantages
Advantages:
Good color density, extended plate life, sharp text definition.
Disadvantages:
Limited tonal reproduction, high printing plate costs, slower speed compared to offset printing.