Electrophotography – Document handling – Copy
Reexamination Certificate
2000-10-23
2002-05-07
Brase, Sandra (Department: 2852)
Electrophotography
Document handling
Copy
C399S407000
Reexamination Certificate
active
06385432
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to electrophotographic image-forming devices, and more particularly to a method of controlling a post-processor that handles continuous paper printed by an electrophotographic image-forming device.
The present invention is suitable, for example, for an output device for use with a computer system that needs to print large amounts of data.
Hereupon, the “electrophotographic image-forming device” by which we mean is an image-forming device employing the Carlson process described in U.S. Pat. No. 2,297,691, and denotes a nonimpact printer that provides recording by depositing a developer as a recording material on a recordable medium (continuous paper in the present invention). The “continuous paper” includes fanfold paper and paper in rolls, and denotes a recordable medium that permits a user's discretionary setting of a recording length. The width of the continuous paper is determined by selecting a type of paper to be used, as necessary, from several types of ready-made paper that have a standardized or predetermined width.
The “post-processor” is a device that carries out one or more of various operations such as cutting, sorting, stapling, etc. after recording on the continuous paper. Characteristically, the post-processor is connected with an image-forming device, and carries out an operation under the control of the image-forming device as a host processor.
In recent years, the electrophotographic image-forming device (continuous paper printer) that uses continuous paper as a recordable medium for printing large amounts of data is typically connected with the post-processor that automatically carries out one or more of various operations such as folding, cutting, sorting, and stapling for the continuous paper. The electrophotographic continuous paper printer, which generally uses a photoconductive insulator (e.g., photosensitive drum, and photosensitive belt), follows the procedural steps of charging, exposure to light, development, and transfer, and the process further includes the fixing step for the continuous paper after the transfer step.
The charging step uniformly electrifies the photosensitive drum (e.g., at −700V). The exposure step irradiates a laser beam or the like on the photosensitive drum, and changes the electrical potential at the irradiated area down, for example, to −50V or so, forming an electrostatic latent image. The development step electrically deposits a developer onto the photosensitive drum using, for example, the reversal process, and visualizes the electrostatic latent image. The transfer step forms a toner image corresponding to the electrostatic latent image on a recordable medium using a transfer unit. The fixing step fuses and fixes the toner image on the medium by the application of heat or pressure, or light irradiation by a fixing unit, thereby obtaining a printed matter.
Conventionally, one printing operation in the continuous paper printer that forms an image on the continuous paper is defined as a process going on after a toner image is transferred from the photosensitive drum to the continuous paper until the fixing unit fixes the toner image. When a print command for one job has been finished, and a subsequent print command for the next job has not been received, the continuous paper on which the last line is printed is at a standstill on a continuous paper feed path in the continuous paper printer. To be more specific, the paper feed stops immediately after the last line has passed through the fixing unit. However, when the command for the next job is issued in this situation, and the printing starts, a blank area in which no image is formed is produced between the last line of the image printed by the immediately preceding job, and the first line of the image to be printed by the next job on the continuous paper. This would waste the continuous paper with a length corresponding to a distance from the fixing unit to a transfer position, and thus impair the use efficiency of the continuous paper. Therefore, a so-called reverse feed has conventionally been carried out that moves back the continuous paper by a specific length when a print command for one job is completed, and no print command for the next job comes. This would improve the use efficiency of the continuous paper.
To give another example, a continuous paper printer that includes first and second image-forming parts, and sequentially records images on both sides of the continuous paper forms the images in each image-forming part spaced out due to mechanical requirements. To be specific, the two-sided printer forms images by following the steps of a transfer on a first side of paper by a first image-forming part, a transfer on a second side of paper by a second image-forming part, a fixing on the first side of paper by the first image-forming part, and a fixing on the second side of paper by the second image-forming part in this sequence. In order to improve the use efficiency of continuous paper in the printer configured as above, the reverse feed amount of the continuous paper (distance at which the continuous paper is conveyed in a backward direction) is configured to be larger than that in a single-side printer.
The post-processor is electrically connected with the continuous paper printer, and carries out operations such as cutting of the continuous paper conveyed. Following is an exemplified post-processor embodied as a burster unit that separates the continuous paper along perforations into individual sheets. The burster unit upon startup of the printing operation simultaneously starts separation of the continuous paper conveyed; thus, the continuous paper has already been separated when the reverse feed is to be carried out in the continuous paper printer, and cannot be conveyed in a reverse direction. Therefore, if the post-processor having no reverse feed capability is connected with the continuous paper printer having a reverse feed capability, the feed of the continuous paper is controlled so that a reverse feed amount of the continuous paper may sag during printing. In addition, the post-processor is manufactured by a maker other than that of the continuous paper printer in many occasions, and thus may be selected among post-processors capable of accepting a specific post-processing command from the continuous paper printer.
A further detailed description will be given of the method of controlling the post-processor with reference to FIG.
9
.
FIG. 9
is a flowchart showing a conventional method of controlling printing operations for explaining the method of controlling the post-processor, where the reverse feed amount (distance from the transfer part to the fixing part) is 50 inches. First, for example, when a print command for one job is issued from a host device such as a computer (step
2
), the continuous paper printer receives the command to initiate printing (step
4
). Subsequently, the image-forming device, which has experimentally worked out the time required to feed continuous paper over a predetermined distance of 50 inches in advance, sets a timer for that time (step
6
). The image-forming device then initiates the operation, and does printing as intended on the continuous paper (step
8
). During the printing operation, if the timer exceeds the set time and indicates zero (step
10
), the image-forming device, construing it to mean that a 50-inch sag has been formed in the continuous paper, transmits a signal to initiate an operation to the post-processor. Until the timer indicates zero (step
10
), the printing operation continues all the way, and the signal to initiate the operation is not transmitted to the post-processor. The post-processor eventually receives the command to initiate the operation, and initiate the operation (e.g., of cutting the continuous paper) (step
12
). If the intended printing operation is completed, the paper feed stops immediately after the last line of the image on the continuous paper has passed through the fixing part. At that
Hanazato Eiichi
Inui Takashi
Wada Yoshinori
Armstrong Westerman & Hattori, LLP
Brase Sandra
Fujitsu Limited
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