What Is The Difference Between Flexographic Printing And Litho Printing?

Flexo printing (a type of embossed printing) and lithography (offset printing) are very different in principle, process characteristics and application scenarios. Here's a closer look:
1.Printing Principles and ink transfer Methods
Flexographic printing
Principle: belongs to embossed printing, the image part of the printing plate is higher than the blank part. During printing, the ink is quantitatively transferred through an the anilox roller the raised image surface of the printing plate and then pressed directly onto the substrate.
Ink transfer:
Direct contact: plate and substrate direct contact, thick ink layer (about 3-5μm), color saturation.
Short-range ink system: Ink from the anilox roller to printing plate, and substrate, the path is short, reducing ink loss and volatilization.
Lithographic printing (offset printing)
Principle: according to the principle of oil-water insoluble, the image part of the printing plate is hydrophilic waterproof material, the blank part is hydrophilic waterproof material. In printing process, the first part of the blank with a moistening fountain solution, then through the ink roller to transfer the ink to the image part, and finally through rubber cloth to press the ink indirectly on the substrate.
Ink transfer:
Indirect contact: Ink is transferred first to the rubber blanket, then from the rubber blanket to the substrate. The ink layer is uniform and thin (about 1-2 microns).
Long ink path System: Ink requires a number of ink rollers and damping device, long path, complex control.
2. Platemaking process and costs
Flexographic printing
Platemaking materials: mainly photosensitive photosensitive resin plates or laser engraving plate, plate making is soft and flexible, suitable for web printing.
Platemaking process:
Digital Document Output → negative film production → exposure → Cleaning → Dry → Post-processing.
Laser engraving plate can omit the negative film step and directly ablate the black film plate with the laser.
Platemaking cost:
Low to medium end (cost of single board about 50-300 yuan), short plate making cycle (a few hours-a day), suitable for short board work.
Lithography (offset printing)
Platemaking materials: using aluminum base PS plate (pre-coated photosensitive plates), plate is hard, flat.
Platemaking process:
Digital file output → CTP plate (computer direct platemaking) → development → cleaning → drying.
Platemaking cost:
Mid-range (about $100 to $500 for a veneer), short the platemaking cycle (a few hours), but requires CTP equipment and a high initial investment.
3. Printing quality and accuracy
Flexographic printing
Dot repair: Traditional flexographic plates have significant dot dot expansion due to elastic deformation (especially for dots below 50%), but can be improved with laser engraving and high-definition anilox rollers with a maximum print volume of 175 lines/inch.
Color performance: ink layer is thicker, color saturation is higher, but the ability to restore dark tone is slightly lower than offset printing.
Registration accuracy: Satellite flexographic machines can register with high accuracy within ±0.1mm and unit flexographic machines with registration accuracy of ±0.15mm.
Lithographic printing (offset printing)
Dot recovery: dot expansion control is accurate, with over 200 lines/inch of high-precision printing, rich in dark tones.
Color performance: uniform ink layer, color reproduction exquisite, suitable for high-end color printing (such as photo album, posters, etc.).
Registration accuracy: High-end offset printing press registration accuracy can be ±0.01mm, much higher than flexographic printing.
IV. INTRODUCTION Substrate and applicable scenarios
Flexographic printing
Base material:
Wrap: Paper, film (PE, PP, PVC), self-adhesive aluminum foil, corrugated paper, etc.
Thickness range: 0.02-10mm, good adaptability.
Application scenarios:
Food packaging (such as beverage bottle labels, snack bags, etc.), soft packaging, pre-printed cardboard boxes, self-adhesive labels, daily packaging, etc.
Advantages: Environmental protection (mainly water-based ink), low cost, suitable for short and medium prints.
Lithographic printing (offset printing)
Base material:
Flat material: coated paper, matte paper, cardboard, synthetic paper, etc.
Thickness range: 0.05-0.5mm, high material flatness requirements.
Application scenarios:
Commercial printing (brochures, leaflets, posters), high-end packaging (cigarette packages, wine boxes, make-up boxes), books, etc.
Advantages: High printing quality, good color reproduction, suitable for mass printing.
V. Environmental protection and cost-effectiveness
Flexographic printing
Environmental protection:
Using water-based ink or UV ink, low VOCs emissions and comply with environmental regulations.
The printing process uses low energy consumption and recycles waste.
Cost-effectiveness:
Low investment in equipment (about $200,000 to $500,000 for a small flexographic machine), low cost of consumables, suitable for small and medium batch printing.
Lithographic printing (offset printing)
Environmental protection:
Traditional offset printing uses solvent type ink, high VOCs emissions, require to be accompanied by waste gas treatment equipment.
Environmentally friendly offset printing (such as alcohol-free fountain solution, soy ink) can be improved, but the cost will increase.
Cost-effectiveness:
Equipment investment (about $1 million to $5 million four-color offset press), suitable for mass printing, low single-page cost.
VI. INTRODUCTION Summary table Summary
Flexo Lithographic printing (offset printing)
Printing principle Letterpress, direct contact printing, indirect contact imprinting printing (rubber blanket)
Ink transfer thick ink layer (3-5μm), high color saturation thin ink layer (1-2μm), color reproduction exquisite.
Low to medium cost and short cycle time
Printing accuracy ± 0.1-0.15mm, point 175 lines/inch Registration ±0.01mm, point 200 lines/inch or more
Substrate Roll material, 0.02-10mm flat, 0.05-0.5mm thick
Applicable scenarios Food packaging, flexible packaging, short-run job, commercial printing, high-end packaging, large-scale printing
Environmental water inks, low VOCs emissions traditional ink high VOCs, environmental protection costs increase.
Cost-effective for small to medium volumes, low equipment investment for large volumes, low cost per page
VII. Selection recommendations
Choose flexographic printing:
Printing of roll materials (such as film, adhesive, corrugated paper) is required.
Environmental requirements (such as food packaging).
Large and medium sized jobs, low cost, high speed.
Choose lithography (offset printing):
High-quality color printing (e.g. photo albums, posters) is needed.
lithographic materials (such as coated paper, cardboard).
Print in bulk, aiming for the lowest cost per page.