Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1998-07-15
2001-06-05
Lee, Cheukfan (Department: 2722)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S474000, C358S406000
Reexamination Certificate
active
06243173
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C §119 from an application entitled Method And Apparatus For Correcting Alignment Error Of Scanning Head Of A Shuttle Type Scanner earlier filed in the Korean Industrial Property Office on Jul. 15, 1997, and there duly assigned Serial No. 97-32746 by that Office.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for correcting an alignment error of a scanning head of a shuttle type scanner and, more particularly to a method and an apparatus for correcting an alignment error of a scanning head of a shuttle type scanner capable of compensating an error occurred in a manufacturing process of a product or the alignment error generated by an impact applied in use.
2. Description of the Related Art
Conventionally, a scanning head having an optical sensor in a shuttle type scanner is transported exactly transverse to a document transporting (feeding) direction. This means that there should be an alignment error equal to zero (0), or no alignment error. Thus, the image distortion does not occur in the scanned image data. Since it is impossible, however, to manufacture a perfect product which has no alignment error due to a manufacturing process or other reasons, the shuttle scanners which are currently being produced are designed to ignore an alignment error within a predetermined limit. Here, the limit of the alignment error varies according to manufacturers of a relevant product and each product. The alignment error limit is roughly set &PHgr;<4° wherein, &PHgr; is an error angle. Accordingly, a product having an alignment error exceeding this limit, it is regarded as an inferior product and a process for mechanically rearranging the alignment error is performed. In the case of a product having the alignment error within this limit, even if the alignment error occurs, it is ignored and the product can be used.
However, in the conventional shuttle type scanner, there is no method for correcting the alignment error regarding the products having the alignment error within the permitted limit. As a result, since the product is continuously used ignoring the alignment error, when a document in a normal state is scanned and the scanned image data is printed, image distortion can occur in the printed image.
It is well known in the art to use the scanner's optical sensor to check for and correct for misalignment of a printing head in a multifunction machine having an optical sensor and ink cartridge, as evidenced by U.S. Pat. No. 5,250,956 to Robert D. Haselby et al. entitled Print Cartridge Bidirectional Alignment In Carriage Axis, U.S. Pat. No. 5,297,017 to Robert D. Haselby et al. entitled Print Cartridge Alignment In Paper Axis and U.S. Pat. No. 5,644,344 to Robert D. Haselby entitled Optical-Print Cartridge System. I have determined, however, that should the print cartridge of the prior art be properly aligned and the optical sensor misaligned, then print cartridge alignment will be changed unnecessarily, resulting in a distorted printed image.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a method for correcting an alignment error of a scanning head having an optical sensor of a shuttle type scanner capable of obtaining a normal print state when performing a scanning operation using the shuttle type scanner.
It is another object of the present invention to provide an apparatus for correcting the alignment error of the scanning head having an optical sensor of the shuttle type scanner.
According to one aspect of the present invention, when an alignment error correction mode is selected, the scanning head is moved to a position facing a correcting pattern formed on a correction plate. The correcting pattern is scanned through the scanning head and the alignment error is calculated from image data of the scanned pattern using a predetermined operation function. After performing a first correction to the calculated alignment error by moving first and last pixels of the image data, a second correction to the alignment error is performed by applying a preset correction function to remaining pixels excluding the first and last pixels.
Selectively, an alignment error correction mode can be set when manufacturing the scanner, when starting the scanning operation, or for every line in which the scanning operation is performed.
Preferably, the correcting pattern has a size of 1×N pixels (here, N is a positive number) in the direction to which the scanning head performs a reciprocatory movement and in the direction perpendicular to the reciprocating movement of the scanning head, respectively. At this time, the size of the correcting pattern in the direction which is vertical to the direction of the reciprocating movement of the scanning head is set to have an equal number of pixels on the vertical axis of the scanning head.
Selectively, the correcting pattern can be set to have an optional color capable of being scanned by the scanning head. Preferably, the correcting pattern has a black color.
Preferably, the operation function is
&PHgr;=tan
−1
D/V
wherein, &PHgr; is an error angle, V is a total number of pixels in the vertical axis and D is the alignment error of the horizontal axis.
Preferably, when performing the first correction, the last pixel is moved in order to be positioned on the same vertical axis as the first pixel.
Preferably, the correction function is a correction function of
d/dV
drop
D=−V
×tan &PHgr;
wherein, D is the alignment error of the horizontal axis, V is the total number of pixels of the vertical axis and &PHgr; is the error angle.
According to another aspect of the present invention, the apparatus for correcting the alignment error of the scanning head of the shuttle type scanner includes: a correction plate which is mounted at a path on which the scanning head performs the reciprocating movement facing the scanning head and includes a correcting pattern which is formed to have a certain size therein; a memory for storing the pattern image data scanned by the scanning head; an operation unit which calculates the alignment error of the pattern image data stored in the memory using a preset operation function; and a central processing unit which controls the reciprocating movement of the scanning head, controls the operation unit to calculate the alignment error of the pattern image data and corrects the calculated alignment error using the correction function.
Preferably, the correction plate is mounted at the path on which the scanning head performs the reciprocating movement, and mounted at a position out of a scanning region of the image recorded in the document. Selectively, the correction plate can be mounted at a left end of the path on which the scanning head performs the reciprocating movement or at a right end of the path.
Preferably, the correcting pattern has an optional color capable of being scanned by the scanning head. More preferably, the correcting pattern has a black color.
Preferably, the correcting pattern has a size of 1 pixel in the direction to which the scanning head performs a reciprocating movement and has a size as many as pixels capable of being scanned by the scanning head in the direction vertical to the reciprocating movement of the scanning head. Selectively, the correcting pattern has a band shape having 1×128 pixels.
REFERENCES:
patent: 4558461 (1985-12-01), Schlang et al.
patent: 5144455 (1992-09-01), Stein et al.
patent: 5250956 (1993-10-01), Haselby et al.
patent: 5280370 (1994-01-01), Faust et al.
patent: 5297017 (1994-03-01), Haselby et al.
patent: 5629771 (1997-05-01), Mikami et al.
patent: 5644344 (1997-07-01), Haselby
patent: 5664076 (1997-09-01), Pluta et al.
patent: 5818976 (1998-10-01), Pasco et al.
patent: 5902993 (1999-05-01), Okushiba et al.
patent: 5912448 (1999-06-01), Sevier et al.
Gahang Goo-Soo
Lee Hyuk-jae
Bushnell , Esq. Robert E.
Lee Cheukfan
Samsung Electronics Co,. Ltd.
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