This invention relates to a mechanism for folding continuous-form sheeting, which is provided with perforations at predetermined intervals so that a part may be torn off easily. The sheeting is supplied in such a state that the sheets of the continuous-form sheeting have been stacked up by alternately folding them at the perforations, in such a way that the sheets of the continuous-form sheet may be stacked up by folding them at the perforations after the formation of images thereon in the same manner as before the formation of the images.
Heretofore, continuous-form sheeting known as fan-folded sheeting has been employed in printers for printing, and particularly for outputs from computers. Such continuous-form sheeting is provided with perforations at predetermined intervals so that a part may be torn off easily and is supplied in such a state that sheets of the continuous-form sheeting have been stacked up by alternately folding them at the perforations.
The use of such continuous-form sheeting (for printing) affords numerous merits including: having output data checked in the order in which the data is output, facilitating proper arrangement of data as it is output continuously, making it possible to supply many sheets of forms without using a stacker, and simplifying sheet feed control, i.e., type position control, with accuracy by means of driving sprocket holes. Each of the sheets of the continuous-form sheeting after being used for printing, are stacked in line with their creases or perforations as before printing.
There have recently been developed imaging apparatus such as laser beam printers, the use of which is expanding steadily, for obtaining hard copies by utilizing electrophotography in a manner similar to electronic copying machines. In such machines, scanning the surface of a photoconductive drum is scanned and charged with a laser beam modulated according to data pertaining to images, such as graphic forms, characters and the like. The surface of the photoconductive drum is exposed to light, and the images are formed on recording sheeting.
Such a laser beam printer has been substantially patterned after the existing electronic copying machine, where a sheet cut in predetermined size, is used as the recording sheet. For a fixing device, a pair of fixing heat rollers are formed by disposing a backup roll in pressure-contact with a heat roller which is heated to a high temperature. In other words, the process generally adopted is a so-called fixation by means of a heat roller, in which recording sheeting carrying an unfixed toner image is passed between the rollers to fix the toner to the sheeting by fusion-bonding. In this case, there is an increased demand for the use of continuous-form sheeting.
When continuous-form sheeting is employed in an imaging apparatus in which the fixing method by means of a heat roller is employed, the perforated creases where sheets are folded tend to become undone, because the continuous-form sheeting heated and pressed, i.e., heat-pressed in the fixing unit of the imaging apparatus. Thus, the continuous-form sheeting is not thereafter easily folded.
The arrangement stated above is therefore disadvantageous in that the continuous-form sheeting discharged from the imaging apparatus is left unfolded or irregularly bent, thus causing disorder in the vicinity of the sheet discharge port as the sheeting is irregularly bent.
Even in the case of conventional printers such as wire dot printers and the like, difficulties arise in the folding and stacking of continuous-form sheeting after printing operations. For this reason, there has been contrived a means for guiding the sheet in a direction along which it is discharged in accordance with the bending direction thereof by providing a rocking guide arm, moving a stacker table back and forth in accordance with the bending direction of the sheeting or the like. However, these means proposed or implemented are invariably complicated in construction and not capable of effectively folding sheeting that has been heat-pressed during heat-roll fixation.