The present disclosure relates generally to a method and apparatus for handling sheet feeding in an imaging device. More specifically, the present disclosure relates to adjusting the print area on a sheet based in part on the detected lengths of prior sheets.
A print zone in a printing context is the area of a media sheet where the printer may create an image of text, drawing or other data as required by a user. Controlling the print zone is an important design and operational criteria for a printer. Should the print zone be too short, then the user will not be able to print much material on a particular sheet. However, if the print zone is too large, then some of the printing may occur outside of the print zone and off of the actual sheet. In such a case, material such as footnotes, page numbers and the like may not be printed on the sheet which may lead to user dissatisfaction.
Some ways of controlling the print zone to ensure that data is printed on the sheet and not lost includes assuming a shorter print zone than might be able to be printed on a sheet therefore ensuring that the print zone always falls within the sheet. Another way of controlling the print zone is to use expensive optical sensors which may accurately detect the leading edge of a sheet which may then be used to adjust the print zone for the printer. However, optical sensors are very expensive and therefore increase the cost of the printing device to the users. Given the highly competitive market place for printing devices today, an increase in cost is a significant factor for manufacturers and consumers to consider.
Other factors that affect a print zone includes tolerances within the printer, tolerances within the sheet media and, in some circumstances, the speed with which the sheets are fed through the printing device. For example, as a printer is used there is some inherent wear in feed rollers, motor bearings and other parts which lead to variations in how a sheet is picked from the storage tray and fed through the printer. These variations may be sufficient to cause differences in the print zone over time. The differences in sheet media can also introduce variations which must be accounted for. In particular, different weights of paper may feed differently creating variations in how the printer feeds the sheet and therefore the resultant print zone. The speed with which the sheets are fed through the printing device can also be a factor as the gap between the trailing edge of a leading sheet and leading edge of a trailing sheet may become so small that errors in sensors may be introduced which leads to print zone variations. All these variations must be taken into account in the design and operation of a printing device to ensure that the print zone remains on a sheet.
Therefore, it would be advantageous, for a printing device to be able to adjust for changes that may occur such that the print zone from one page to another remains in an acceptable range for the user.
The invention can be better understood with reference to the following drawings. The attached drawings, in which like references indicate like parts, are included solely to illustrate a preferred embodiment of the present invention without lending the invention in any manner whatsoever.
One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
It should be appreciated that the sheets 105 while illustrated as rectangular sheets, may be any type of suitable sheet media material and may come in various sizes of plain paper, coated paper, card-stock, envelopes, transparencies and the like. The sheet tray 103 may also include one or more adjustment mechanisms for accommodating different sizes of print sheets such as a sliding length adjustment lever, a sliding width adjustment lever and other mechanisms known in the art. In some embodiments, a sensor associated with the paper tray, or otherwise positioned in the printing device, may indicate to a processor or like device controlling the printing device the sheet type and/or the size of the sheet being fed. This information may be used by the printing device to determine a default print zone for that particular sheet.
As was discussed previously, due to the different weights of paper sheets, and other tolerance issues, a mechanism is advantageously incorporated within the printer device 101 to make sure the print zone remains in an acceptable range and position on a printed sheet. Although the edge detector 113 may detect a leading and a trailing edge of a sheet such as sheet 107, due to various tolerances within the detector, due to mechanical issues and the like, may cause variations in the detected edge either of the leading edge such as 111 or trailing edge such as 201 from their actual position within the printing device 101.
The printing device 101 may use information from one or more sheet sensors to determine the sheet size and type to thereby determine the default step count to utilize.
If at step 303 a valid sheet step count is available then the printing device 101 will use the valid sheet step count to determine the beginning of a print zone as indicated in step 309. Whether the valid sheet step count is available such as in step 309 or a default sheet step count is used as in step 305, the step count available be it the default step count or the valid step count is utilized to position the sheet such as sheet 107 at the proper location to correspond with the beginning of a print zone on the sheet.
Once the sheet is properly positioned at the beginning of a print zone, then the sheet may have an image printed on it and as the image is being printed, the sheet is being advanced by a stepper motor, not shown. After the image has been transferred to the sheet such as sheet 107, the end or trailing edge of the sheet such as trailing edge 201 will be detected by a sensor such as sensor 113. Once the trailing edge has been detected, then the number of steps from the leading edge such as leading edge 111 to the trailing edge such as trailing edge 201 will be known and that step count may be stored in a memory such as memory 503 as a valid sheet step count as illustrated in step 311. Other types of sheet drive systems, other than stepper motor systems, may also be employed from which the length of the sheet may also be determined and stored in a memory such as memory 503 to be used to adjust the print zone on subsequent sheets.
The method illustrated in
The first print zone may be considered to start at line 403 and end at line 407. This first print zone may be the default print zone utilized by the printing device 101 if a valid sheet step count is not available as was described in association with
The second print zone may be considered to start at line 405 and end at line 409. This second print zone may be utilized if a valid sheet step count is available. By using a valid sheet step count determined as described in association with
An I/O control device 505 may be coupled to the processor 501 such that the processor 501 may control a stepper motor 507 that may be utilized by printer device 101 to drive the sheet feeder mechansism 508 to move the sheets such as sheet 105 through the printing device. Additionally, the edge detector 113 may be coupled through the I/O control to processor 501 so that processor 501 may detect either a leading or a trailing edge of a sheet.
A data input circuit 409 may be utilized to provide the processor 501 with data that a user may wish to be imaged by the printing device 101. In addition, the data input circuit 509 may also be utilized to output status data to an external computer, not shown.
Of course, variations, modifications and changes to the present invention will make themselves apparent to one skilled in the art from a reading of the present disclosure. All such modifications, variations and changes are intended to fall within the scope of the present invention only limited by the appended claims. For example, while a printing device 101 is illustrated as an electrophotographic printer, other printer devices such as inkjet printing devices may also be utilized advantageously to implement the described herein invention. Also, the terms imaging and printing are intended to be defined broadly and may encompass text or graphics.
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Number | Date | Country | |
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20060115307 A1 | Jun 2006 | US |