Carbon

Carbon paper is a carbon coated tissue that is collated onto the face of a part that requires an image transfer. It is available in blue and black, but black is generally used on any type of continuous form that is going to be imprinted on an impact printer. It is available in an all over carbon coating or as a pattern carbon coating where only certain areas are carbon coated and the other areas are blank tissue. Carbon is generally less expensive to run but many users do not like it because it is dirtier to work with. Carbon may be an option selected when hot spot carbonizing cannot be applied to the back of the preceding part because it requires backprinting in the area where the carbonizing ink would be applied.
 

Pattern carbon is generally used between the fly sheet and the face of the outgoing envelope so that only selected areas are printed on the envelope.

All over coated carbon may be used to image the inserts within the outgoing envelope. The mailer can be manufactured so that the carbons come out with the inserts or so that they stay in the mailer when the inserts are extracted.

 
Carbonizing Bond

Carbonizing bond is the most widely used form of selective image transfer for multiple part mailers. The carbonizing ink is applied on the press. It is applied to the part that precedes the part that needs to be imaged. The coating can cover almost the entire back side or it can be applied in just selective areas. It is also one of the least expensive methods used for selective image transfer. There are different grades and varieties of carbonizing ink available. The type you choose will depend on the type of image you are trying to achieve, from a lighter sharp impression to a heavy dark impression. The type you select will also depend on how many parts you are going to be imaging through. Carbonizing bond is a very good method of image transfer and the carbonized area will hold its transfer quality for an indefinite period of time.

Although carbonizing bond is a good selection for image transfer, there are some disadvantages to it. One is that it has a tendency to smudge from excessive handling. Another is that it is always active, meaning it does not need any other special coating that it needs to come in contact with to make an impression. This may be a problem if the carbonized sheet is used in an environment outside of the mailer itself. Also, the carbonizing bond is not recyclable.
 

The hot spot carbonizing would be used on parts where only selective copy is to be imaged, such as on the back of the file copy so that only the delivery address was transferred to the face of the outgoing mailer.

The all over carbonized coating would be used on the back of the part preceding the insert where all imprinted information needs to be transferred.

 
Carbonless Paper

Carbonless paper is paper that is coated with chemicals that produce an image when they are combined. There is CB - coated back, CFB - coated front and back, and CF - coated front. See Continuous Forms - Carbonless Paper for more details on how carbonless paper works. Carbonless paper is popular because it is clean to use, you do not have to worry about the smudging carbon coating. When using carbonless paper, you have to have the proper mate for each part to transfer an image. CB needs CFB or CF, and CFB needs CF. The CF is an image receiver only, it cannot transfer an image. Carbonless paper is more expensive to use but because of its user friendliness, people are willing to pay extra to use it. The disadvantage of using carbonless paper for a mailer is that to have selective image transfer, you have to use desensitizing to prevent transfer in the areas that you do not want an image to appear. An alternative is to use carbonless stock on the parts that have full imaging required and use one of the other imaging methods on the parts that require selective imaging.
 

CB carbonless stock could be used as the top part of the mailer and CF carbonless could be used for the back of the mailer. When the two are in contact with each other and pressure is applied by an impact printer, an image occurs on the CF stock.

Another area that carbonless stock could be used is on a multiple part insert. CB stock would be used on part 1 of the insert to combine with CF stock used for part 2 of the insert.

 
Self contained paper is another type of carbonless paper that can be imaged just by impact. It does not need any other special paper to make an impression. This paper could be used to get image transfer when other methods are not available for use. For example, if a special paper had to be used on the preceding part that was not available as a carbonless paper and it had a full printed backer that would eliminate the use of hot spot carbonizing, self contained could be used because it would be imaged just by the impact of the printer. One of the biggest disadvantages of self contained paper is that it does image by impact, so any additional contact has the potential of marking the paper.

Carbonless Coatings

Most manufacturers have the capability of applying some type of spot carbonless coatings. There are CB, CF and self contained coatings available to spot coat areas for selective imaging.
 

CB Spot Coat - A CB spot coat would be applied to the back of any type of paper. The following part would have to be a CF paper to receive the image transfer from the CB coating.

CF Spot Coat - A CF spot coat would be applied to the face of the part that needs to be imaged and the preceding part would have to be a CB paper for the CF spot coat to be imaged.
 

Self Contained Coating - The self contained coating does not require any other chemical transfer to create an image. Like the self contained paper, it images upon impact alone. The use of a self contained patch in the delivery address area allows the use of a carbonless ribbon to imprint the mailer. This would also eliminate the need for a blockout on the face of the outgoing mailer. The disadvantage of the self contained coating is the same as the self contained paper, it has the potential to be marked up and smudged by any type of impact.

The carbonless coatings can be used on most any type of paper which gives you a larger selection of paper to use on your mailer. It eliminates the need for desensitizing and pattern carbons. The mailer is less bulky and cleaner to handle because the use of carbon paper and carbonizing bond is eliminated. The use of carbonless coatings may not be feasible on shorter runs because of the additional set up time required but on longer runs it is generally less expensive than the use of carbonless paper.