Thermal printing

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A thermal printer Sharp CE-126P.jpg
A thermal printer
Bills and receipts are typically printed on thermal paper. Twitter receipt printer.jpg
Bills and receipts are typically printed on thermal paper.

Thermal printing (or direct thermal printing) is a digital printing process which produces a printed image by passing paper with a thermochromic coating, commonly known as thermal paper, over a print head consisting of tiny electrically heated elements. The coating turns black in the areas where it is heated, producing an image. [2]

Contents

Most thermal printers are monochrome (black and white) although some two-color designs exist.

Thermal-transfer printing is a different method, using plain paper with a heat-sensitive ribbon instead of heat-sensitive paper, but using similar print heads.

Design

A thermal print head Thermal printhead.jpg
A thermal print head

A thermal printer typically contains at least these components:

Thermal print head at high magnification Thermal printhead macro.jpg
Thermal print head at high magnification

Thermal paper is impregnated with a solid-state mixture of a dye and a suitable matrix, for example, a fluoran leuco dye and an octadecylphosphonic acid. When the matrix is heated above its melting point, the dye reacts with the acid, shifts to its colored form, and the changed form is then conserved in metastable state when the matrix solidifies back quickly enough, a process known as thermochromism.

This process is usually monochrome, but some two-color designs exist, which can print both black and an additional color (often red) by applying heat at two different temperatures. [3]

In order to print, the thermal paper is inserted between the thermal head and the platen and pressed against the head. The printer sends an electric current to the heating elements of the thermal head. The heat generated activates the paper's thermochromic layer, causing it to turn a certain color (for example, black).

Thermal print heads can have a resolution of up to 1,200 dots per inch (dpi). The heating elements are usually arranged as a line of small closely spaced dots. [4]

Early formulations of the thermo-sensitive coating used in thermal paper were sensitive to incidental heat, abrasion, friction (which can cause heat, thus darkening the paper), light (which can fade printed images), and water. Later thermal coating formulations are far more stable; in practice, thermally printed text should remain legible for at least 50 days.[ citation needed ]

Applications

Thermal printer used in seafloor exploration Ocean Exploration EPC Thermal Printer.jpg
Thermal printer used in seafloor exploration

Thermal printers print more quietly and usually faster than impact dot matrix printers. They are also smaller, lighter and consume less power, making them ideal for portable and retail applications.

Commercial use

Commercial applications of thermal printers include filling station pumps, information kiosks, point of sale systems, voucher printers in slot machines, print on demand labels for shipping and products, and for recording live rhythm strips on hospital cardiac monitors.

Record-keeping in microcomputers

Many popular microcomputer systems from the late 1970s and early 1980s had first-party and aftermarket thermal printers available for them, such as the Atari 822 printer for the Atari 8-bit family, the Apple Silentype for the Apple II, and the Alphacom 32 for the ZX Spectrum and ZX81. They often use unusually-sized supplies (10CM wide rolls for the Alphacom 32 for instance) and were often used for making permanent records of information in the computer (graphics, program listings etc.), rather than for correspondence.

Fax machines

A fax machine from Panasonic with integrated answering machine, beginning of the 1990s. The thermal paper was sold in rolls which were inserted into a compartment in the device. After a completed transmission, the printed document was automatically cut off from the roll and remained in front of the machine. Panasonic KX-F90.jpg
A fax machine from Panasonic with integrated answering machine, beginning of the 1990s. The thermal paper was sold in rolls which were inserted into a compartment in the device. After a completed transmission, the printed document was automatically cut off from the roll and remained in front of the machine.

Through the 1990s, many fax machines used thermal printing technology. Toward the beginning of the 21st century, however, thermal wax transfer, laser, and inkjet printing technology largely supplanted thermal printing technology in fax machines, allowing printing on plain paper.

Seafloor Exploration

Thermal printers are commonly used in seafloor exploration and engineering geology due to their portability, speed, and ability to create continuous reels or sheets. Typically, thermal printers found in offshore applications are used to print realtime records of side scan sonar and sub-seafloor seismic imagery. In data processing, thermal printers are sometimes used to quickly create hard copies of continuous seismic or hydrographic records stored in digital SEG Y or XTF form.

Other uses

Flight progress strips used in air traffic control (ACARS) typically use thermal printing technology.

In many hospitals in the United Kingdom, many common ultrasound sonogram devices output the results of the scan onto thermal paper. This can cause problems if the parents wish to preserve the image by laminating it, as the heat of most laminators will darken the entire page—this can be tested beforehand on an unimportant thermal print. An option is to make and laminate a permanent ink duplicate of the image.

The Game Boy Printer, released in 1998, was a small thermal printer used to print out certain elements from some Game Boy games.

Health concerns

Reports began surfacing of studies in the 2000s finding the oestrogen-related chemical bisphenol A ("BPA") mixed in with thermal (and some other) papers. While the health concerns are very uncertain[ citation needed ], various health and science oriented political pressure organizations, such as the Environmental Working Group, have pressed for these versions to be pulled from market. [5]

See also

Related Research Articles

<span class="mw-page-title-main">Printer (computing)</span> Computer peripheral that prints text or graphics

In the field of computing, a printer is considered a peripheral device that serves the purpose of creating a permanent representation of text or graphics, usually on paper. While the majority of outputs produced by printers are readable by humans, there are instances where barcode printers have found a utility beyond this traditional use. Different types of printers are available for use, including inkjet printers, thermal printers, laser printers, and 3D printers.

<span class="mw-page-title-main">Mimeograph</span> Type of duplicating machine

A mimeograph machine was a low-cost duplicating machine that worked by forcing ink through a stencil onto paper. The process was called mimeography, and a copy made by the process was a mimeograph.

<span class="mw-page-title-main">Laser printing</span> Electrostatic digital printing process

Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image. The drum then selectively collects electrically charged powdered ink (toner), and transfers the image to paper, which is then heated to permanently fuse the text, imagery, or both, to the paper. As with digital photocopiers, laser printers employ a xerographic printing process. Laser printing differs from traditional xerography as implemented in analog photocopiers in that in the latter, the image is formed by reflecting light off an existing document onto the exposed drum.

<span class="mw-page-title-main">Dot matrix printing</span> Computer printing process

Dot matrix printing, sometimes called impact matrix printing, is a computer printing process in which ink is applied to a surface using a relatively low-resolution dot matrix for layout. Dot matrix printers are a type of impact printer that prints using a fixed number of pins or wires and typically use a print head that moves back and forth or in an up-and-down motion on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper. They were also known as serial dot matrix printers. Unlike typewriters or line printers that use a similar print mechanism, a dot matrix printer can print arbitrary patterns and not just specific characters.

<span class="mw-page-title-main">Inkjet printing</span> Type of computer printing

Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensive consumer models to expensive professional machines. By 2019, laser printers outsold inkjet printers by nearly a 2:1 ratio, 9.6% vs 5.1% of all computer peripherals.

<span class="mw-page-title-main">Daisy wheel printing</span> Impact printing technology

Daisy wheel printing is an impact printing technology invented in 1970 by Andrew Gabor at Diablo Data Systems. It uses interchangeable pre-formed type elements, each with typically 96 glyphs, to generate high-quality output comparable to premium typewriters such as the IBM Selectric, but two to three times faster. Daisy wheel printing was used in electronic typewriters, word processors and computers from 1972. The daisy wheel is so named because of its resemblance to the daisy flower.

<span class="mw-page-title-main">Dye-sublimation printing</span> Digital printing technology with wide color range

Dye-sublimation printing is a term that covers several distinct digital computer printing techniques that involve using heat to transfer dye onto a substrate.

<span class="mw-page-title-main">Dots per inch</span> Measure of dot density

Dots per inch is a measure of spatial printing, video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm). Similarly, dots per centimetre refers to the number of individual dots that can be placed within a line of 1 centimetre (0.394 in).

<span class="mw-page-title-main">Game Boy Printer</span> Printing accessory for the Nintendo Game Boy series of handheld games consoles

The Game Boy Printer, known as the Pocket Printer in Japan, is a thermal printer accessory released by Nintendo in 1998 which ceased production in early 2003. The Game Boy Printer is compatible with all the Game Boy systems except the Game Boy Micro and is designed to be used in conjunction with the Game Boy Camera. It also prints images from compatible late-generation Game Boy and Game Boy Color games. It runs on six AA batteries and uses a proprietary 38mm wide thermal paper with adhesive backing, originally sold in white, red, yellow and blue colors. In Japan, a bright yellow Pokémon version of the Game Boy Printer was released, featuring a feed button in the style of a Poké Ball.

<span class="mw-page-title-main">Thermal-transfer printing</span> Digital printing method

Thermal-transfer printing is a digital printing method in which material is applied to paper by melting a coating of ribbon so that it stays glued to the material on which the print is applied. It contrasts with direct thermal printing, where no ribbon is present in the process.

<span class="mw-page-title-main">Label</span> Material affixed to a container or article with printed information

A label is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed directly on a container or article can also be considered labelling.

<span class="mw-page-title-main">Thermochromism</span> Property of substances to change colour due to a change in temperature

Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an excellent example of this phenomenon, but thermochromism also has more practical uses, such as baby bottles which change to a different color when cool enough to drink, or kettles which change color when water is at or near boiling point. Thermochromism is one of several types of chromism.

A platen is a flat platform with a variety of roles in printing or manufacturing. It can be a flat metal plate pressed against a medium to cause an impression in letterpress printing. Platen may also refer to a typewriter roller which friction-feeds paper into position below the typebars or print head. It can refer to the glass surface of a copier, and the rotating disk used to polish semiconductor wafers.

<span class="mw-page-title-main">Wide-format printer</span> Computer-controlled printing machine

Wide format printers are generally accepted to be any computer-controlled printing machines (printers) that support a maximum print roll width of between 18 and 100 inches. Printers with capacities over 100 in wide are considered super-wide or grand format. Wide-format printers are used to print banners, posters, trade show graphics, wallpaper, murals, backlit film (duratrans), vehicle image wraps, electronic circuit schematics, architectural drawings, construction plans, backdrops for theatrical and media sets, and any other large format artwork or signage. Wide-format printers usually employ some variant of inkjet or toner-based technology to produce the printed image; and are more economical than other print methods such as screen printing for most short-run print projects, depending on print size, run length, and the type of substrate or print medium. Wide-format printers are usually designed for printing onto a roll of print media that feeds incrementally during the print process, rather than onto individual sheets.

Coated paper is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absorbency. Various materials, including kaolinite, calcium carbonate, bentonite, and talc, can be used to coat paper for high-quality printing used in the packaging industry and in magazines.

<span class="mw-page-title-main">Thermal paper</span> Adding machine, cash register and credit card terminal paper

Thermal paper is a special fine paper that is coated with a material formulated to change color locally when exposed to heat. It is used in thermal printers, particularly in inexpensive devices such as adding machines, cash registers, and credit card terminals and small, lightweight portable printers.

Dye transfer is a continuous-tone color photographic printing process. It was used to print Technicolor films, as well as to produce paper colour prints used in advertising, or large transparencies for display.

A contract proof usually serves as an agreement between customer and printer and as a color reference guide for adjusting the press before the final press run. Most contract proofs are a prepress proof.

A thermal copier or thermocopier is a kind of photocopier based on the effect of heat. The original sheet feeds in conjunction with the "thermo-sensitive" paper, generating a copy on its specially treated surface. The black parts on the original sheet, once scanned, make the copier activate the heating elements that produce some chemical reactions on the "thermo-sensitive" copy paper that darkens its surface. After the process, a stable black-and-white image is obtained on the cooled film or paper.

<span class="mw-page-title-main">Zink (printing)</span>

Zink is a full-color printing technology for digital devices that does not require ink cartridges and prints in a single pass.

References

  1. "Receipt Paper: Why It Fades and How to Restore It?". Panda Paper Roll. 2018-12-10.
  2. "Definition of THERMAL PRINTER". www.merriam-webster.com.
  3. Diamond, Arthur S. (2018-10-08). Handbook of Imaging Materials. CRC Press. p. 445. ISBN   978-1-4822-7736-4.
  4. "Thermal Print Head | Toshiba Hokuto Electronics Corporation". www.hokuto.co.jp.
  5. "Concerned About BPA: Check Your Receipts". Science News. Retrieved 2021-04-19.