Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
1998-07-27
2001-10-16
Tran, Huan (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06302510
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and device for judging printing status of a printing device provided in a printer, a facsimile machine, and the like.
2. Description of Related Art
There has been known a printing apparatus, such as a printer, a facsimile machine, and the like, provided with a printing device such as an ink jet print head formed with a plurality of nozzles. Ink is supplied to the print head from an ink tank provided within an ink cartridge. The print head will perform defective printing when ink runs out of the cartridge. The printing apparatus therefore detects whether or not the ink tank has run out of ink. For example, the printing apparatus may calculate the number of times printing has been performed by the print head. Or, the printing apparatus may directly detect the amount of ink remaining in the ink tank. When determining that the ink tank has almost run out of ink, then the apparatus displays a message for urging a user to replace the ink cartridge with a new one. This replacing operation can prevent the print head from performing defective printing.
SUMMARY OF THE INVENTION
However, the print head may perform defective printing even when sufficient ink remains in the ink tank. That is, nozzles of the print head can sometimes become clogged so that quality of printing becomes poor. The above-described method for detecting whether ink has run out or not is incapable of detecting degradation of print quality caused by clogged nozzles. Therefore, printing will continue even if print quality becomes poor because the nozzles are clogged.
This is particularly a problem in facsimile machines that print images based on data transmitted from an external device, and then erase the data from the memory after printing the corresponding images. In this case, even if the user later notices that the images were not properly printed because of clogged head nozzles, he or she can do nothing to reprint them, because the corresponding data no longer exists.
It is conceivable to provide an improved printing apparatus which can automatically check reduction in quality of printed images, regardless of whether the reduction in quality is caused by clogged nozzles or by ink running out. In this conceivable printing apparatus, the print head is controlled to print a quality-check mark on a margin portion of a print sheet. The print head is controlled to print the quality-check mark at a predetermined position in the margin portion and to have a predetermined size. The conceivable printing apparatus is provided with a reflection type sensor for irradiating the quality-check mark with light and then for receiving light that reflects off the quality-check mark. The reflection type sensor is designed to output a detection signal whose value corresponds to the amount of the received light. The detection value is then compared with a threshold value. When the detection value is smaller than the threshold value and is near to a predetermined white level, then it is determined that printing is defective.
Individual printing apparatuses are commonly stored with fixed data indicative of the predetermined position and size, at which the quality-checking mark should be printed. Accordingly, in all the printing devices, the print head prints the quality-check mark on the print sheet at the same position and by the same size. Individual printing apparatuses are, however, slightly different from one another at the position where the reflection type sensor is attached. Individual printing devices are also slightly different from one another at the position of the path, along which the print sheets are transported, relative to the print head. These hardware variations will discourage some printing apparatuses to attempt to accurately detect the quality-check mark. That is, the reflection type sensors in some printing apparatuses become unable to accurately detect the density of the quality-check mark. For example, even when printing is being properly performed, the reflection type sensor may possibly fail to accurately detect the quality-check mark and therefore may determine that the printing situation is degraded.
In order to solve this problem, it is conceivable to increase the size of the quality-check mark to insure that it is detected by the reflection type sensor. However, in this case, the large quality-check mark would be noticeable to users so such a solution is not desirable.
It is an objective of the present invention to overcome the above-described problems and to provide an improved method and apparatus which is capable of printing a quality-check mark in a size and at a position within the sheet appropriate for detection by the reflection type sensor, and therefore which can accurately detect a printing status of a printing device such as a print head.
In order to attain the above and other objects, the present invention provides a method for detecting a printing state of a printing device, the method comprising the steps of: setting a printing condition for printing a quality-check mark on a printing sheet with using a detection sensor; controlling a printing device to print a quality-check mark at the set printing condition on a printing sheet; controlling the detection sensor to detect the quality-check mark; and determining a printing state of the printing device based on the detected result.
According to another aspect, the present invention provides a printing apparatus for printing a desired image on a printing sheet with a printing device while detecting a printing state of the printing device, the apparatus comprising: a printing device capable of printing a desired image onto a printing sheet; a detection sensor capable of detecting a state of a mark printed on a sheet; mark printing condition setting means for setting a printing condition for printing a quality-check mark on a printing sheet with using the detection sensor; print control means for controlling the printing device to print a desired image on the printing sheet and to print a quality-check mark at the set printing condition on the printing sheet; detection control means for controlling the detection sensor to detect the quality-check mark; and determination means for determining a printing state of the printing device based on the detected result.
According to still another aspect, the present invention provides a method for determining a printing status of a printing device, the method comprising the steps of: transporting a mark selection sheet, the mark selection sheet being printed with a plurality of position setting marks and a plurality of size setting marks at positions separated from one another in a sheet transport direction of the mark selection sheet, the plurality of position setting marks being printed in the same size and at different print positions from one edge of the sheet, the plurality of size setting marks being printed in different sizes and at the same print position from the edge of the sheet, the mark selection sheet being transported so that the position setting marks and the size setting marks serially reach a predetermined reflection type sensor positioned at a predetermined detection position; controlling the reflection type sensor to serially detect the position setting marks and the size setting marks, the reflection type sensor irradiating light onto each position setting mark and each size setting mark and receiving light reflected therefrom, thereby outputting a detection signal; setting, in a rewritable non-volatile memory, a print position of one of the plurality of position setting marks that allows the reflection type sensor to output a detection signal nearest to a predetermined black level; determining at least one of the plurality of size setting marks that allows the reflection type sensor to output a detection signal capable of being regarded as the predetermined black level, selecting one of the determined at least one size setting mark that has the smallest size among the at least one size setti
Brother Kogyo Kabushiki Kaisha
Oliff & Berridg,e PLC
Stewart Charles W.
Tran Huan
LandOfFree
Method and apparatus for detecting printing status of print... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for detecting printing status of print..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for detecting printing status of print... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2597589