Do Laser Printers Really Use Lasers?

This laser printer is ubiquitous in our daily lives, leading the pack as far as computer printer sales go. But they are also the great deceivers of the printing realm. Because although the word ‘laser’ suggests that a beam of light is what transfers ink to paper, the reality is quite different.

The Laser is Only a Small Part

Despite being included in the name of the process and printing machine, the laser’s role in printing is actually a small one. At its core, the printing process which involves the laser is known as electrophotography and is based on the same two physical principles: static electricity and photo-conductivity. The electrophotographic printing process was invented in 1971, with the first laser printers entering the market in 1984.

The Principles

The principle of electrostatic attraction is that any material can carry a static electric charge, and therefore be attracted to or repelled by another material, dependent on strength and polarity of that charge. In the case of the laser printer, the toner carries a charge which attracts it to the image-carrying areas of the printer’s photoconductor.

The principle of photoconductivity is that some plastic and semiconductors will act in the dark as insulators, but act in the light as conductors. Therefore, if coated with a photoconductive material, any surface will charge in the dark to a high voltage. In the light, an image can be printed on that surface. Any place the light hits is where static electricity will be discharged. This effectively stores an image on the photoconductor in static.

The Photo-Conductive Surface

The surface of a laser printer that is photo-conductive is its drum. Made of metal, the outside of this drum contains one or more plastic layers. In addition to providing a photoconductive surface, the drum provides structural support, as well as temporary image memory during printing.

The surface of the drum serves as an insulator when in darkness, and so takes on a negative charge when it passes in darkness near a charged wire.

Laser Light Scanning

The role of the laser is to ‘paint’ the image to be printed onto the drum. Scanning from side to side, the laser works at the same time the drum is turning. This forms a raster pattern. This exposure of the drum to the laser’s light discharges its negative surface charge to the metal layers beneath, effectively transferring the image there in the form of static electricity.

Making the Image Visible

Once the static image has been transferred, the next step is to make it visible. This is done by introducing small toner particles to the drum’s static-charged surface. The vessel which holds the toner and iron filings is called the developer. This hopper is positioned facing the drum at very close proximity, with a charge equal to that of the drum. This ensures that the toner sticks only to areas where laser light has touched the drum and transferred the image in electro-static form.

As the developer rotates, a thin layer of filings coated with toner is sent toward the drum. The developer’s magnet causes the toner-coated filings to stand on their ends as they move past the drum and define the image in toner.

The Transfer Station

The now toner-defined image on the drum rotates until it is positioned over the paper, placing them both over what is known as a transfer station. Carrying a positive charge, the transfer station attracts the toner from the metal of the drum and transfers it to the paper. Following this action, the drum is cleaned by ‘eraser lights’ and a blade which removes excess toner, returning the drum to its clean state.

The result of the electrophotographic printing process is a printed image onto the paper’s top layer that is made of a very thin, melted plastic layer. This process is often employed where the printing of security labels is required, as it allows for label text to be protected against the ravages of light, weather and temperature.

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Don’t Go Against The Grain with your Labels

The quality of any printed document is vital. Whether a brochure, book, business card or set of inkjet labels, the products you have professionally printed will pass through a number of hands during their lifetimes. Unfortunately, there is one ‘silent killer’ which can render your printed materials practically unusable if overlooked. This killer is not understanding how paper grain affects printed items.

Paper Manufacturing and Printing

During papermaking, pulp is spread across a wire, and paper grains – also known as fibres – align themselves in a single direction, according to how the paper machine moves. This direction will either be parallel to the longest dimension of the sheet, or to the short side of the paper. Grain short paper is the result when fibres align to the paper’s short side, where grain long indicates fibre alignment with the long side of the paper. The direction of the grain will ultimately depend on how that paper has been cut.

During the printing process, paper is exposed to a wide range of conditions that cause it to expand and contract. As well, any glues or moisture that happen to be present will also cause expansion and contraction. In fact, paper fibres running against the grain can expand and contract up to 400% more than those running with the grain.

How Grain Affects Paper After Folding

When folded in a direction that goes against paper grain, there is far less risk of structural damage to the paper. However, if the paper being folded is of a heavier weight, the paper surface can crack. Therefore, the best way to fold paper is by whichever grain direction is parallel to your desired fold or score.

When folding occurs parallel to the grain, far fewer paper fibres get broken, and the fold is much stronger. If there is any doubt, the theory can be tested at home, simply by folding light stock paper in each direction, and then examining the quality of the folds. The fold which will appear cleaner and smoother will be the one that was folded parallel to the paper grain.

Smooth Paper is the Ideal

All printing, including that of inkjet labels relies on paper smoothness. The smoother the paper being printed on, the higher the image and print quality will be. The rougher that a paper’s surface is, image quality in terms of half-tones and solids will suffer. Paper that’s extremely rough will not even hold ink; instead, the roughness will cause ink to flake off or disintegrate when rubbed.

Rough paper will also not display images or print correctly in terms of fineness; for example, if an image contains delicate lines or a font is in fancy scripted format, these details may not accurately display on rough paper. This is because the many varied surfaces of rough paper don’t allow it to come in close enough contact for ink to adhere to it.

Roughness can be worked with

A printing press cannot correct the surface irregularities which cause paper roughness. However, they can be worked with by the application of ink in higher densities. However, this may not necessarily prevent ink from rubbing or flaking off when handled.

Some inkjet labels such as those used on cartons may indicate their grain direction. But if the paper being used doesn’t indicate this, grain direction can be determined simply by looking at the numbers. For example, paper sizes are indicated in width by length format. So if you’re using 11×17 paper. The grain direction would be long, with the paper fibres going in the 17-inch direction. Other times, the long grain side of the paper may appear in bold font.
Many printing production errors can be completely avoided by paying attention to grain direction.

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The Blockout Label: When Should it be Used?

Labels are useful for many reasons. But a label is only as good as it is accurate. And so when the print on labels becomes inaccurate, outdated or redundant, it’s important to be able to correct or, at least, cover up this information as quickly and easily as possible. The blockout or opaque label offers a solution for problematic inkjet labels.

Blockout labels work because they contain an opaque coating on the front or back of the label face, use an adhesive that is opaque, or are completely constructed of opaque material. This type of label also exists in combinations of the three. Where adhesive is concerned, common colours include black, grey or dark blue. However, opaque adhesives do exist in a number of other colours.

Potential Requirements

The purpose of the opaque label is to quickly cover up the information on existing thermal, laser or inkjet labels. And there are many reasons why this kind of label may be required.

Packaging Re-Use

Opaque labels can help companies avoid the continuous and expensive manufacture of packaging. For example, the packages in which stock is delivered do not have to be rendered unusable. They can be easily re-purposed by using opaque labels to cover up outdated shipping information or addresses.

Maintenance of Filing and Stock Systems

Another way an opaque label can be of great benefit is in the office and the warehouse. Instead of paying for new file folders or damaging existing folders by ripping their labels off, all that’s needed is to apply an opaque label. These can also work well in cases where a well-established stock layout needs to maintain its integrity. Using an opaque label can allow for information to be neatly and completely covered so that there is no risk for mishandling or misplacing of files and items.

Accurate Information

The updating of information is one popular use of the opaque label. Companies who have printed promotional materials or special packaging may use the opaque label to cover up information that is no longer accurate. Most of the time, this is done in order to save money. Instead of having an entire run of brochures or packaging re-printed in order to reflect a small change such as a different address, an opaque label placed carefully over the incorrect information, and then filling in the updated address is all that’s needed.

Increased Legibility

Where errors in label choice, design or ink type have caused print to become illegible, opaque labels can save the day. They provide a solid background onto which new information can be printed, and any bold colours or designs that previously interfered with print readability can be covered. Here as well, business owners can save money, as they can avoid the added cost and time investment of having to redesign and reprint their labels.

Health and Security

Blockout labels are often used on pharmaceutical products to ensure that no inaccurate information is visible to the reader or recipient. As well, these labels can be used to completely prevent sensitive or critical information from being seen and read by unauthorised parties.

One of the greatest advantages of the blockout label is the fact that it can not only be pre-printed with updated or correct information; these labels are also available in a wide range of colours to suit virtually any product. A lot of printing companies follow the Pantone standard for printing, which means that any chosen colour can be accurately reproduced on a printer.

Available in A4 sheets or rolls, opaque labels can usually be printed in a range of colours and to client specifications. Where opaque labels are not an option, consider layering standard labels until the original print is no longer visible, or choose labels of a thicker width, such as polyester labels to cover up unwanted information.

Making The Right Label Printing Choices

There are several elements to ensuring that your labels are printed correctly by professionals. These include your label design, desired colours and type of paper being printed on. But the manner in which your inkjet labels are printed can also make a big difference. And here, your choices will be digital and lithographic printing. Each has its own set of benefits and disadvantages.

The Digital v. Lithographic Difference

Digital printing sees your image being sent right from your or your chosen printing company’s computer to printed form without any steps in between. Lithographic printing involves first burning the received image onto a plate, which is transferred to a rubber medium and then printed.

Colour Quality

Lithographic printing is great if you need the colours on your labels to match Pantone colours. This is because the lithographic printing process uses Pantone brand ink. Pantone represents the industry standard for colour. This is a benefit because regardless of the printer you choose, as long as you have chosen to use Pantone colours in your design, your printer can match the inks exactly. This means far less guess work and adjustment to the colours on your labels and ultimately, less time for the completion of your printing job.

Labels that are printed using the digital method will have no standard by which to match colour; instead, colour needs to be simulated by matching cyan, magenta, yellow and black in particular combinations. In some cases, a professional printer will have printing presses equipped with high-quality systems for matching colours. When in doubt, it’s best to ask your chosen printer.

Cost

Because digital printing takes less time for set-up, less of a cost tends to be involved. As well, usually with digital printing there are no initial costs or minimum print runs to be concerned about before your labels are printed. For labels needing various names, numerical sequences or addresses, digital printing can offer a cost-effective choice.

The fact that plates need to be created adds cost to the lithographic option. This type of printing requires proofing to ensure that the correct finish and colours are being produced which also adds to the cost. However, the more labels you plan to print, the lower the cost the job will be.

Proofing Time

Any quality printer will provide a proof of your printing job. Lithographic proofs, as with the actual print job will require a plate to be made. As well, the printing press will need to be set up to make the proof. Digital proofs offer accuracy, as the printed proof you receive will look exactly like the final product.

Choice of Materials

Thanks to recent technological advances, digital printing can be done on a number of materials of varying finishes and weights. However, if you want your printing done on an unusual or rarely-used material, the lithographic printing process can offer a high degree of reliability as well.

How Long Will It Take?

The lithographic printing process requires drying time, simply because of the way in which ink is transferred to the material during printing. Thus, it can take several days before printing can be considered to be completed. But with digital printing, you can often pick up your labels 24 hours after having sent the artwork to your printer.

As stated earlier, there are many considerations when you wish to have labels printed professionally. At the end of the day, your chosen printing method will depend not only on the length of time you wish to wait, but what kind of quality you want your labels to have, as well as what material you are printing your labels on.

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Spot and Process Colour Printing Considerations

When you need more than one type of item printed, the issue of colour consistency is something that can come up. For example, in addition to inkjet labels you may need business cards or brochures. All of these different mediums will each display colour differently and absorb ink at a different rate. How, then, can you ensure that everything you need looks professional and put together?

Issues with Spot Colour

Spot colour is that which has been matched to a swatch of colour, much like would be provided by a paint store. Pantone colour is the industry standard for the lithographic printing process, which uses Pantone brand inks. This allows for exact colour matching.

Choosing a standard Pantone colour shouldn’t cause any printing issues on ink jet labels. However, should you require the same colours to be printed on a brochure or business cards, colour variation can be the result. This can be due both to the thickness of material being printed on as well as its colour.

Issues with CMYK, or Process Colour

Process colour combines cyan, magenta, yellow and black to achieve particular colours. Spot colours can be re-created with CYMK colours, although with caveats: some Pantone colours are more troublesome than others, and can end up looking like completely different shades once printed on inkjet labels or other items.

Questions to ask before Printing

Once you’re able to understand the two different printing types, you’ll need to think about a few things before sending your label printing project to a professional printer.

One Process or Two?

First, you’ll need to decide whether you wish your entire order to be printed using a single process, or whether one portion will need to be printed using the second process. For example, if you wish your labels to be printed with CYMK, but need your business cards to be printed in spot colour, you may wish to ask your printer to print the cards first, and then match their colours to those that will be printed on your labels. This will allow for better colour matching on your labels.

Is there room for Variation?

Are the colours you’re using absolutely critical? If you have a particular business colour that leaves no room for variation, this is something that you will need to communicate to your printing company. And to communicate that clearly, the best thing you can do is to simply print your desired colour directly from your inkjet or laser printer. Regardless of how the colour may look on your screen, it’s the accuracy of the colour on your printout which will matter most, and the one your printing company will be able to work with best.

Future Requirements

It’s also important to consider the future. Will you be needing other items printed later on? If so, it’s a good idea to keep a few of whatever items you are happy with. If you’re satisfied with the colour of your labels, or with the matching between these and your business cards, for example, then you’ll want to keep some of these to give to a future company. While you may think that foregoing these samples and just going with a Pantone reference when trying to communicate your colour preferences will help, it may only serve to confuse both you and the printer.

Another item to consider is when you or another person will be creating your artwork. Whichever the case, it’s critical that you contact your printer to ensure that they will able to work with what you’re creating. This will involve notifying them of any software you’re using to create your artwork. When working with someone else, you’ll need to tell them how your labels and other items will be printed so that this can guide their work. Your printer can also supply you with all of the advice you may need for a perfect print job.