Printing Technology & Digital printing

Wednesday, August 27, 2008

Digital printing accounts for approximately 9% of the 45 trillion pages printed (2005 figure) around the world.

Printing at home or in an office or engineering environment is subdivided into:

* small format (up to ledger size paper sheets), as used in business offices and libraries

* wide format (up to 3' or 914mm wide rolls of paper), as used in drafting and design establishments.

Some of the more common printing technologies are:

* blueprint—and related chemical technologies.

* daisy wheel—where pre-formed characters are applied individually.

* dot-matrix—which produces arbitrary patterns of dots with an array of printing studs.

* inkjet—including bubble-jet—where ink is sprayed onto the paper to create the desired image.

* laser—where toner consisting primarily of polymer with pigment of the desired colours is melted and applied directly to the paper to create the desired image.

* line printing—where pre-formed characters are applied to the paper by lines.

* heat transfer—like early fax machines or modern receipt printers that apply heat to special paper, which turns black to form the printed image.

Vendors typically stress the total cost to operate the equipment, involving complex calculations that include all cost factors involved in the operation as well as the capital equipment costs, amortization, etc. For the most part, toner systems beat inkjet in the long run, whereas inkjets are less expensive in the initial purchase price.

Professional digital printing (using toner) primarily uses an electrical charge to transfer toner or liquid ink to the substrate it is printed on. Digital print quality has steadily improved from early color and black & white copiers to sophisticated colour digital presses like the Xerox iGen3, the Kodak Nexpress and the HP Indigo Digital Press series. The iGen3 and Nexpress use toner particles and the Indigo uses liquid ink. All three are made for small runs and variable data, and rival offset in quality. Digital offset presses are called direct imaging presses; although these receive computer files and automatically turn them into print-ready plates, they cannot insert variable data.

Small press and fanzines generally use digital printing or more rarely xerography. Prior to the introduction of cheap photocopying the use of machines such as the spirit duplicator, hectograph, and mimeograph was common.

For every newspaper, book, or other printed product, there is a production crew laboring behind the scenes, from printing press operators to bindery workers. As a printing technology major, you’ll learn the skills necessary to plan, prepare, and complete print jobs, from assembling film to operating printing equipment to cutting and collating the finished product.

Most programs offer both old-school and new-school techniques, so by the time you graduate, you’ll be prepared for hands-on production work as well as cutting-edge desktop publishing.

source:internet only

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Modern printing technology

Across the world, over 45 trillion pages (2005 figure) are printed annually. In 2006 there were approximately 30,700 printing companies in the United States, accounting for $112 billion, according to the 2006 U.S. Industry & Market Outlook by Barnes Reports. Print jobs that move through the Internet made up 12.5% of the total U.S. Printing market last year, according to research firm InfoTrend/CAP Ventures.

Offset press

Offset printing is a widely used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.

Currently, most books and newspapers are printed using the technique of offset lithography. Other common techniques include:

* flexography used for packaging, labels, newspapers.

* hot wax dye transfer

* inkjet used typically to print a small number of books or packaging, and also to print a variety of materials from high quality papers simulate offset printing, to floor tiles; Inkjet is also used to apply mailing addresses to direct mail pieces.

* laser printing mainly used in offices and for transactional printing (bills, bank documents). Laser printing is commonly used by direct mail companies to create variable data letters or coupons, for example.

* pad printing popular for its unique ability to print on complex 3-dimensional surfaces.

* relief print, (mainly used for catalogues).

* rotogravure mainly used for magazines and packaging.

* screen printing from T-shirts to floor tiles.

Gravure

Gravure printing is an intaglio printing technique, where the image to be printed is made up of small depressions in the surface of the printing plate. The cells are filled with ink and the excess is scraped off the surface with a doctor blade, then a rubber-covered roller presses paper onto the surface of the plate and into contact with the ink in the cells. The printing plates are usually made from copper and may be produced by digital engraving or laser etching.

Gravure printing is used for long, high-quality print runs such as magazines, mail-order catalogues, packaging, and printing onto fabric and wallpaper. It is also used for printing postage stamps and decorative plastic laminates, such as kitchen worktops.

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How Scanners Work ? Tips and tricks

Monday, August 18, 2008

Scanners have become an important part of the home office over the last few years. Scanner technology is everywhere and used in many ways:

  • Flatbed scanners, also called desktop scanners, are the most versatile and commonly used scanners. In fact, this article will focus on the technology as it relates to flatbed scanners.
  • Sheet-fed scanners are similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner looks a lot like a small portable printer.
  • Handheld scanners use the same basic technology as a flatbed scanner, but rely on the user to move them instead of a motorized belt. This type of scanner typically does not provide good image quality. However, it can be useful for quickly capturing text.
  • Drum scanners are used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams. Each beam is sent through a color filter into a photomultiplier tube where the light is changed into an electrical signal.

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How to Buy a Scanner?

Wednesday, August 13, 2008


Step1 Buy a low-resolution scanner only if you will use it just to scan text.

Step2
If you don't plan to scan from books or magazines, consider a sheet-fed unit, which takes up far less desk space than a flatbed scanner.

Step3
Purchase a low-resolution or medium-resolution scanner if you plan to scan photographs to use on the Internet, as the resolution of Web graphics is low anyway.

Step4
Buy a high-resolution scanner if you plan to scan photographs to print and you have a high-resolution printer (greater than 600-by-600 dots per inch, or dpi).

Step5
Buy a model with 36-bit color depth if you plan to scan photographs or color graphics.

Step6
Purchase a parallel-port scanner if you don't expect to use the scanner often or work
with large files.

Step7
Remember that even scanners that cost less than $100 will provide a good picture'600-by-1,200-dpi resolution. Scanners priced between $150 and $250 usually provide 1,200-by-1,200-dpi resolution.

Step8 Know that speed is the biggest factor in pricing. Parallel-port scanners, which use your existing printer port, are the cheapest and slowest. USB scanners, which require that your computer have a USB port, are faster and cost more. SCSI-card scanners are the fastest and most expensive. You need to install a SCSI card in your computer if it does not have one.



Tips & Warnings


* Your computer will need at least 32 (ideally 64) MB of RAM to scan.


* Don't buy a scanner that has greater resolution than your printer or display device. The extra money will be wasted. Make sure the scanner includes scanning software, an image-editing program and an OCR program

* Some manufacturers mislead consumers with resolution claims.

* Optical resolution is the primary determining factor of quality.

* Be wary of small flatbed scanners that use a CIS (contact image sensor) instead of a CCD (charge-coupled device). They are more reliable but produce inferior image quality and color.




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How to Buy a Printer

step 1 Consider the various sizes, shapes, and capabilities. They range from portable printers to printer/copier/scanner/fax combinations the size of a small filing cabinet. Combination units (called all-in-one or multifunction printers) are great if you're short on space, but be sure to test the features that are most important to you.

Step2 Decide between ink-jet and laser printers. How you'll use the printer will guide your decision.

Step3 Choose ink-jet if you print infrequently, or if you're going to print color pictures. Ink-jet printers are less expensive, but can cost more per printed page because of expensive inks.

Step4 Go for a laser printer if you mainly print text (and lots of it), and you want fast, permanent printing. They cost more up front, but less in the long run due to cheaper supplies. Longer lasting laser printers can be repaired more easily and less expensively.

Step5 Buy a brand name to help ensure that you'll be able to get service, software, support and supplies in the future. Brother, Canon, Epson, Hewlett-Packard and Lexmark are the leading brands.

Step6 Confirm your computer's operating system, especially with older machines, supports the printer. Printer drivers come with the printer, but you can also download them from the manufacturer's Web site. (Search for the driver to confirm that the printer will work with your computer.)


Tips & Warnings

  • By law, the printer's warranty remains in effect even if you use toner or ink produced by a company other than the original manufacturer.
  • It's probably not worth having an inexpensive ink-jet printer repaired if it breaks.
  • Some manufacturers void a printer's warranty if you use refilled ink cartridges.

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