In photofinishing, a customer typically delivers one or more rolls of exposed photographic film to a photofinisher, and requests prints (which may be made on a transparent media but are usually on a reflective media such as paper). The film is first developed, if not already developed, and prints are formed by either optically (e.g. with an optical enlarger) or digitally printing at a printing gate of a printer onto a photosensitive medium in the form of a sheet or continuous web. In digital printing, the images from the developed film are first scanned to obtain corresponding digital image signals, which following any desired digital image processing, may be printed onto the photosensitive medium using a suitable digital image printer, such as a laser printer, LED printer, or a CRT printer. The photosensitive medium is then developed (that is, chemically processed to yield a fixed image). Each customer order will typically include many prints. In the case where a photosensitive web is used for printing, multiple orders will have to be separated and typically multiple prints within each order will also have to be separated. Even when the printer uses individual sheets of photosensitive media for each order, at least some (and often, all) of the prints within an order will typically have to be separated from one another.
Prints are separated from one another by a cutter. The cutter has conventionally received its instructions from a code punched through the photosensitive media at or near the printing gate. After the photosensitive media carrying the printed images has been developed, this punch code is read and instructions provided to the cutter. The punched code is typically obliterated or cut off during the cutting step if the photofinisher cuts the prints, or cut off by the customer at a later time since, in either event a customer often only wishes to see images without borders. Such a system is described in U.S. Pat. No. 4,506,824, this system allowing cutting of prints on lines both across and along the direction of the web. Thus, many different sized prints can be accommodated across the width of the photosensitive web.
In the photofinishing operation, the final prints of an order must be kept together and matched with the corresponding customer film. One way of doing this is to print a code or human readable characters (such as alphanumeric characters) on the back side of each print or at least one of the prints in the customer order. Such back side printing can be done after the prints have been developed. This method would require some means of tracking the location of which prints belong with a particular customer film, so that any information unique to particular prints can be printed on the back side of the correct prints. However, customer films are usually batched on a single reel, and the reel is often moved between independent components (e.g. film developer and printer) in the photofinishing process. Further, the resulting prints are often in a batch (such as on a reel) which must also be moved between an independent printer, developer and cutter. Thus, keeping track of which prints belong to a given customer order or which film they are associated with, becomes a daunting task. The task of such tracking can be substantially reduced if the customer identification is printed on the back side of the print media (that is, the side opposite the photosensitive side). One way of accomplishing such back side printing is described in U.S. Pat. No. 4,629,312.
In addition to printing information on the back side of the photosensitive medium which identifies the prints for later association with a corresponding customer film, it may also be desirable to print other information on the back side. Such information may include picture taking conditions (e.g. date, lighting used, and the like), as well as advertising for the photofinishing outlet or others. However, printing any information on the back side of an undeveloped photosensitive media can create problems. In particular, the ink used often does not completely withstand the chemical development steps. This not only leads to loss of resolution of the printed matter, but can lead to contamination of the photoprocessing chemicals by ink or its reaction products which are leached from the photosensitive media during chemical developing. Furthermore, as developed web is rolled back onto a reel, or in the case of individual photosensitive sheets, as the developed sheets are stacked one on top of the other, the back side of one print is pressed against the emulsion carrying side (which now carries the developed image) on the front side. This can result in transfer of ink from the back side to the front side, particularly since the emulsion may still have a high water content at this point.
It would be desirable then, to provide some way of enabling printing on the back side of a photographic print, which does not result in the possibility of introducing printing inks into the chemical developing process, which reduces the possibility of ink transfer from the back side onto an incompletely dry image carrying emulsion, and which does not require complex means of tracking particular prints or customer orders between the image printing station, the developer, and the cutter.