What is an Impact Printer?

Impact printers continue retaining some utility across industries requiring multipart forms, machine-readable output, and longevity in harsh conditions. This article covers the fundamentals of what impact printers have, the types still relevant, and the specifics of working for each.

Impact printers refer to those employing some kind of physical striking mechanism to transfer pigment onto media by either pressing an inked ribbon against paper through hammering or hammering the paper against an inked band. They generate printable output through pressure contact and shape deformation rather than using lasers, inkjets, or thermal technologies. This enables handling special formats like carbonless copy paper.

• Banking and Financial Services: Impact printers are still used extensively in banks to print passbooks, account statements, checkbooks, loan documentation, and other financial instruments. They also print the typical end-of-day branch transaction reports. The ability to print reliably on multi-page carbon copy forms is especially useful.
• Retail Billing and Invoicing: In retail stores and distribution warehouses, dot matrix printers are preferred for printing invoices, delivery challans, purchase orders, credit notes, etc. that often require duplicate and triplicate copies. The speed and paper handling of impact printers fit well.
• Government Form Printing: Especially in developing countries, various government agencies rely on heavy-duty impact printers for standardized forms printing including customs declaration forms, property registration forms, permits, tax payment receipts, etc.
• Legal Services: Law firms, courts, and legal process outsourcing companies use impact printers capable of printing sequentially numbered legal documents, case documents, and other agreements requiring secure handling and long-term archival given the ink permanency.
• Healthcare: Several hospital information management systems meant for patient admissions, prescription handling, and documentation integrate impact printers for longevity in high-volume hospital environments and the ability to print copies for documentation adherence.
• Logistics and Transportation: Airlines, railways, shipping yards, and road transportation companies use impact printers for flight manifest printouts, consignment notes preparation, vehicle log book generation, and freight delivery challans creation thanks to their speed and reliability.

While many legacy impact printers like daisy wheel and line printers are now obsolete outside niche applications, two longstanding forms retain everyday utility.

1. Dot Matrix Printers

Dot matrix printers contain print heads of thin metal pins that extend to strike an ink ribbon and transfer dots onto paper when needed. Varied pin combinations produce complete characters and graphics to compose printable output augmented with carriage movement.

Key components in a dot matrix printer include:

• Print Head: Houses a vertical column of metal pins that get individually triggered to extend out and print or retract back when not needed for a specific dot position. High quality heads use jeweled tips.
• Inked Ribbon Cartridge: Usually a multipart ribbon cloth saturated in quick drying ink that sits between the print head and paper allowing ink transfer upon pin impact.
• Stepper Motor: Controls horizontal print head motion to facilitate printing full page width rather than just printable column under fixed head. This allows composing the dot matrix output.
• Paper Feed Roller: Feeds continuous stationery paper vertically with perforations that engage the sprocket tractor. Ensures paper alignment.
• Electronics Interface: Inputs digital signals from computer I/O and converts them into electrical commands for print head pin firing order and hammer retractions based on dot pattern requirements.

2. Daisy Wheel Printers

In this type of printer a pre-molded wheel is used which is known as daisy wheel thats why its named as daisy wheel printer. This wheel rotates at fast speed inside printer and prints text on the paper. The daisy wheel contains characters and symbols at the end of each petal or spoke.

Working of daisy wheel printer

• The daisy wheel is made of plastic or metal and contains all alphanumeric characters and punctuation symbols needed for printing on the tips of its petals.
• It spins at very high speed as it prints and must be changed when a different font style is needed.
• As the wheel spins rapidly, a hammer strikes the back of individual petals precisely, causing that character to hit an ink ribbon and be transferred onto the paper with a crisp, clear imprint.
• The imprint is of high quality as full characters are transferred rather than dotted patterns.
• However, the sequential striking of petals as the wheel rotates makes it slower than some other printers.

3. Line Printers

Line printers are high-speed, high-volume impact printers that print complete lines of text at one time using entire sets of characters on spinning drums or bands inside the printer. They focus upon lines that makes them faster.

Working of Line Printers

• Designed for data centers, businesses, institutions needing high throughput printed output
• Print heads consist of spinning metal drums or bands wrapped around pulleys that contain the full set of characters, numbers, and symbols arranged in lines.
• As the drum or band rapidly spins, one line of text, number or symbols gets pressed against the ink ribbon at once through a synchronized striking mechanism.
• This causes the entire line to get printed onto continuous paper fed into the printer.
• Extremely fast as print an entire line together instead of printing character by character.
• Output speed ranges from over 1,000 to nearly 2,000 lines per minute.

4. Band Printers

Band printers are high-speed impact printers that utilize metal bands carrying embossed characters that turn around pulleys within the printer to put marks on paper.

Working of band printers

• Reliable heavy-duty printers built for high duty cycles.
• Use metallic bands that rotate about pulleys powered by motors.
• Bands are embossed with letters, numbers, special symbols in the form of characters.
• The bands move at very fast rate and press an entire row of type against an inked ribbon.
• The ribbon then imprints the ink onto the paper below.
• Band rotation is precisely controlled allowing printing of 2000 lines or more per minute.
• Ideal for printing multi-part stationery as characters strike with strong mechanical impact.

• Reliable and Durable Operation: The mechanical construction of impact printers enables them to withstand vibrations, dust, humidity and varying temperatures better than laser or inkjet printers containing sensitive electronic parts.
• Low Operating Costs: Once purchased, impact printers only require occasional ribbon changes, periodic lubrication, and inked band/print head replacements roughly every 2-3 years.
• Security and Safe Operation: As impact printers do not employ lasers, inks or heat for operation, they pose no electric shock hazards or burn risks to users changing consumables like bands or ribbons.
• Multipart Form Printing Ability: The inherent nature of pins or hammers striking ribbons or bands with force transfers inks adequately to print even up to 4-6 underlying carbon copies legibly in dot matrix printers, important for invoices and waybills.
• Controlled Environment-Friendly: Unlike toner powders that pose inhalation issues needing air filtration or inkjet cartridges demanding complex recycling, impact printer consumables like single color inked bands have more eco-friendly disposal once depleted through usage.

• Very Slow Speed and Noisy Operation: The mechanical aspects limit impact printer top speeds to 300-500 characters per second for dot matrix and marginally better at 500-1000cps for LQ printers compared to over 25 pages per minute for contemporary laser printers.
• Only Monochrome Printing Ability: Whether bands, ribbons or matrix pins, impact systems rely on single color inks restricting output only to monochrome text or data representations.
• Inferior Print Quality: While letter quality band printers manage near typewriter quality, fixed pin spacing and ribbon dragging in dot matrix constrains print sharpness below laser printer 600+ dpi resolutions.
• Frequent Consumable Changes Needed: Inked cloth bands last 12-24 months seeing paper volumes before needing replacement. Multi-pass ribbons used up faster with hundreds of meters length ratings typically.
• Requires Custom Printer Interface Support: Most modern operating systems like Microsoft Windows dropped native integration with impact printers requiring special DOS drivers or compatible interfaces like Serial, Parallel ports.

Can I connect an impact printer to my smartphone?

No. Impact printers require a specific interface like a USB port or serial port to connect to devices, which smartphones do not have. You would need to connect them to a desktop computer or with an adapter.

Are impact printers suitable for printing photos?

No. Impact printers can only print in monochrome and lack the high resolution or color capabilities required for photographic printing. They are only designed for printing text and simpler images.

What is the difference between a typewriter and an impact printer?

Typewriters allow typing letters directly onto paper. Impact printers take electronic input and can then print much faster, store data digitally and use fonts beyond just typewriter ones. But they use similar mechanical striking technologies.

Can I leave paper continuously in an impact printer?

Yes. Most impact printers have an in-built tractor feed that allows loading a stack of continuous paper with perforations on the sides. This enables printing multiple documents without manually feeding sheets.