Electrophotography – Document handling – Copy
Reexamination Certificate
2001-02-05
2003-10-14
Beatty, Robert (Department: 2852)
Electrophotography
Document handling
Copy
C399S385000, C399S394000, C399S299000
Reexamination Certificate
active
06633740
ABSTRACT:
BACKGROUND
1. Field of Invention
This invention is an improved on demand media web electrophotographic printer with a feeding and cutting registration apparatus, including a method that reliably monitors and controls consistent media web feeding, registration, and the cutting of the web by utilizing a sensor system that includes a web buckle sensor to form a precise web buckle prior to each feeding and cutting. Utilizing a gap or indicia sensor, the processor accurately positions media, including media edges and performs a unique, more productive; automatic on-line operating setup of the media web with the cutting of each desired length. An improved initial setup of the roll of plain media, including adhesive backed media web spaced on a “backer” roll for minimizing downtime and media wastage.
2. Description of Prior Art
On demand prior art printer apparatus, such as thermal transfer, address the technical problem of maintaining media web feeding and accurate printing without wastage by integrating into the apparatus, complex sensing and web compensation means, with the cutting of the web following printing. This thermal printer cutting method does not aid in the on line maintaining of the accuracy of registration. With thermal transfer, the printer automatic sensing and compensation means may frequently stop the printing operation to off-line adjust the media web and to more accurately position the media leading edge and media gap or indicia prior to printing. This level of complexity requires additional downtime for the operating setup of media printing which increases cost, lowers productivity, and reduces reliability. Also, there is much more downtime in the frequent changing of low capacity, high cost thermal media ribbons at greater expense than the electrophotographic (EP) printer high capacity toner cartridge of the present invention.
The present invention relates to the industrial marking market and the kind of on demand printer that generally uses media web special Printouts or non-standard sheet sizes, as opposed to the office document printers and copiers, which use a series of standard sheet sizes starting with 8.5″×11″. Industrial marking media web Printouts vary in length and width for text information and images related to transactions, data, identification, and includes photos, barcodes, labels, tags, tickets, narrow web receipts, and the like. Industrial marking also includes special cut sheet sizes for color labels, airline tickets, RFID tags, ID cards with photos, credit cards, and the like. These special cut sheet sizes may be web cut, and they may be web processed or separately handled in cut sheet feeders and stackers. The completed Printouts may be laminated in clear plastic. Industrial marking Printouts include “spot colors” or full-color, i.e. yellow, magenta, cyan, and black.
On demand prior art industrial marking printers such as thermal transfer media web printers are designed to operate with a variety of media types, including pressure sensitive, die-cut, butt-cut, or stock media web. The type of media sensors the printer has, dictates its ability to operate with certain media types. Unless the media is a plain continuous web, die cuts, black marks, or notches help the printer determine the top of the media.
Thermal transfer printers come equipped with a variety of media sensors that enable the printer to gauge fixed vertical media length during the media calibration process. Automatic Off Line Calibration is a process that is typically performed by a web thermal transfer media printer in order to gauge the length of the media material loaded within it and compensate for error build up from repeated print cycles. Sensors within the printer's media compartment—commonly located around the thermal printhead—detect either the white spaces (inter-media gaps) or black marks and/or notches on the reverse side of the media stock that represent a media's actual face size (length). Printer calibration ensures that the data is aligned and prints correctly on the media stock and is also cut correctly at the media gap or indicia after printing. The printer media sensors of the prior art may frequently stop printing to recalibrate off-line, resulting in excessive downtime and wasted media.
Prior art media web thermal printers are configured to contain any one of the below sensor varieties:
Transmissive Media Sensor is used to gauge media length for media with visible inter media gaps, notches, or pre-punched holes, or plain continuous media
Reflective Media Sensor is a reflective sensor emits light, which is reflected back to the sensor when it reaches an indicia or black mark.
Dual Media Sensors are two sensors within the printer (one reflective and one transmissive) that have the ability to detect both inter media gap and black mark media.
Multi-functional Sensor refers to a single sensor within the printer that has the ability to detect both inter media gap and black mark media, irrespectively.
EP printers are excellent at printing the highest quality bar code Media Web, text and graphics on plain paper media. Bar code density is also quite high on EP printers resulting in a scannable code at virtually any wavelength using an infrared scanner. However, widely used standard laser office page printers are not well suited for industrial media web applications. Here, they prove inadequate and wasteful, as it is impossible to produce single or small media lengths. (A minimum of at least ½ standard page of media is typically. required for the printer apparatus nips to maintain feeding control of the sheet. Unless the media is at least that size, the remainder is wasted). Since EP printers have been developed to process relatively long cut sheets, and continuous web EP applications tend to waste media when starting and stopping, electrophotographic technology has not been widely used for media web printing. In addition, the conventional EP apparatus (unlike the small footprint Media Web EP printer with very short media length capability of the present invention) has been developed with an inherently long media path of operating nips of subassemblies to accomplish the processes of latent imaging, toning, transfer, and fusing. A certain minimum length of the web is necessary to engage the nips of these prior art process units in order that a driving relationship in the printer is maintained. With current electrophotographic (EP) methods, the minimum length of a media sheet is limited by the allowable configuration, location or spacing of the nips between these operating subassemblies of the printer. As a result attempting to cut the media after the media is printed and is being ejected results in an overly long margin and waste of media.
Since EP printers have mechanically spread apart, functions of latent imaging, toning, and fusing, their web feeding and cutting apparatus must include means such as a web buckle of the media at the cutter to allow a clean severing of the stationary media, during the process of printing with precisely controlled leading and trailing edges without media wastage. However, unconstrained web feeding can result in an over size buckle causing a media jam. And, an undersize buckle does not allow enough time for a clean cut, resulting in irregular tearing and jamming of the media. Rapid printer response is required in most on demand applications, and it is desirable to have the web buckle formed ready for the print command. However, over a prolonged standby period, a permanent set of the web buckle may occur causing a media jam at the start of the next print cycle. These conditions are made worse by variations in the thickness and stiffness of the media.
The media web EP prior art discloses a web buckle accumulation apparatus and method for the control of the web unidirectional feeding and cutting during the printing process. EP web printers U.S. Pat. No. 3,639,053, and U.S. Pat. No. 5,768,675 disclose a web buckle accumulation method. With this method, the media web EP registration roll feed unit advances
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