The present invention relates to a magnetic ink character recognition system provided in an electrostatographic printer and to a method for controlling characters produced by magnetic ink character printing. Preferably, the invention relates to controlling the application of magnetic ink characters by electrostatographic printing and to a magnetic ink character recognition system.
The process of electrophotographic printing may include sensitizing the surface of an photoconductive member by charging to a substantially uniform potential. The charged portion of the photoconductive surface is exposed to a light image of an original document being reproduced. The light image selectively discharges portions of the surface thereby recording the image of the document. Alternatively, a modulated light beam, i.e., a laser beam, may be utilized to discharge the photoconductive surface to record the desired information. In this way, an electrophotographic latent image is recorded on the photoconductive surface. The image corresponds to the information desired to be reproduced. After the image is recorded on the photoconductive member, it may be developed by contact with developer material. The developer material may comprise toner particles adhering triboelectrically to carrier granules, or alternatively a single component development system may be employed. Both the carrier granules and toner particles may be magnetic, the toner particles having ferromagnetic parities encapsulated in a thermoplastic resin binder. The toner particles are transferred from the carrier granules to the latent image to form a toner powder image on the photoconductive member which is subsequently transferred to a copy sheet. The copy sheet is heated to permanently affix the powder image.
Electrostatographic printing is useful for producing checks or financial documents with magnetic characters for the banking industry and for other businesses producing financial instruments. The process involves fusing magnetic toner particles on the checks or documents to provide encoding in a magnetic ink character recognition (MICR) format. High speed processing of financial documents is simplified by imprinting magnetic ink characters and/or bar codes in a machine readable form. The magnetic character codes permit repeated processing of financial documents and their high speed sorting. Encoded information may be imprinted on financial documents with magnetic ink or toner. The resulting document copies may be subsequently read by an MICR reader and processed.
Ozaki et al., U.S. Pat. No. 4,736,315, disclose an apparatus for evaluating density and evenness of printed patterns including a circuit for calculating density distribution of imaged data, a circuit for normalizing density distribution with an area of affective image data and a circuit for quantifying the density and evenness of patterns.
Will, U.S. Pat. No. 4,797,938, discloses a process of identifying MICR characters comprising generating an analog signal representative of the characters, digitizing and storing values representing the analog signals, locating positive and negative peaks of the analog signals, testing the peaks against a first plurality of repeating patterns to determine which of the patterns fit the peak stored for the character, using a pattern which best fits the peaks to select the stored digitized values and testing the stored digitized values against the second plurality of patterns representing a set of characters which can be identified in order to identify the read character.
Word et al., U.S. Pat. No. 4,891,240, disclose printing MICR characters wherein the area in which the characters are to be printed is prelubricated.
Parker et al., U.S. Pat. No. 4,901,114, disclose an electronic printer employing tri-level xerography to superimpose two images during a single pass in a printer. One part of the composite image is formed using MICR toner, while the other part of the image is printed with less expensive black or color toner.
Aoki, U.S. Pat. No. 4,980,726, relates to a toner density control device for an electrophotographic copier with two sensing circuits, a toner density sensing circuit and an image density sensing circuit. Toner is supplemented whenever one of the two sensing circuits fails.
Matsuhashi et al., U.S. Pat. No. 4,984,281, relates to a magnetic ink character recognition system that includes a field unit for receiving digital signals from a storage unit and for sorting the digital signals from each field plus a decision unit for receiving the signals from the sort unit and for judging the thickness of ink characters and determining a representative thickness value for each character and a correction unit for correcting the digital signals from the storage unit based on decision data from the decision unit for each character and a recognition unit for determining whether or not the corrected signals are readable.
Smith et al., U.S. Pat. No. 5,083,157, relates to an electrophotographic printing machine wherein a nonmagnetic toner image is transferred to a copy substrate and MICR readable images are formed out of the previously fused non-magnetic image. A film is utilized and includes a heat resistant backing member and, a magnetic media adhered to the backing member. The film is used to press magnetic media against predetermined portions of nonmagnetic images. The film is heated to cause magnetic media to fuse to the selective non-magnetic image areas.
Corona et al., U.S. Pat. No. 5,083,159, discloses a method for providing initial optimized performance of an illumination and exposure system used to form a latent image at an exposure station of a document on a photosensitive medium, including the steps of introducing a linear photosensitive display consisting of a plurality of photodiodes to an exposure station, energizing an illuminator to produce a light output which is transmitted through the exposure station and is incident along the length of the array, converting the output of the photosensitive array into video signals representative of the average illumination output of the illuminator, providing a bar graph on a display screen of the average illumination error superimposed against a horizontal specification line on the display representing a maximum acceptable illumination level, and positioning the illuminator while observing the bar graph and selecting the alignment position at the lamp at which the bar graph is at a minimum value relative to the specification line.
Baus, U.S. Pat. No. 5,091,961, discloses a check reader which is operative with a variable check movement rate. The bank reader imposes a set of flux reversals over the magnetic ink characters to be read. The flux reversals permit a pulse count sequence to be generated which is unique to each magnetic ink character independent of the rate of check movement.
Kozlowski, U.S. Pat. No. 5,134,663, relates to a system and method for recognizing MICR characters including establishing a center line between first and last peaks of a scanned magnetic electrical readout, established in a location of major peaks, comparing the peak magnitudes and peak locations with parameters in a predetermined template. The magnitudes and locations are scored according to error deviation. The lowest scored template is then found to identify the character read.
Canu et al., U.S. Pat. No. 5,151,952, discloses an apparatus for detecting the position of edges in scanned characters and comparing them to the edges of selective characters and utilizing the ratio between the distances determined and using the ratio to compare to a stored set of standard ratios to identify the character scanned.
Butler, U.S. Pat. No. 5,162,874, discloses an electrophotographic apparatus having a densitometer. The apparatus includes means for generating diffused signal representative of the diffused component of light reflected from material placed on a substrate; means for generating a compensation ratio; means, responsive to the compensation ratio, for generating a compensated specular; and means responsive to the diffused signal for determining density of the material; and a means responsive to the compensated spectral signal for calibrating the determining means.
Application of magnetic ink to a copy sheet is a delicate process. The objective is to have a correct amount of magnetic ink deposited on a continuous basis. Too much magnetic ink causes smearing and too little will not provide a readable signal. In either instance, the magnetic ink characters are not accurately recognized.
It is desirable to provide a system for monitoring printed magnetic ink characters to assure that a correct amount of ink is deposited on a continuous basis. In a system, the printed magnetic characters may be read and compared to standard printed magnetic characters. The electrophotographic printer may be adjusted to resolve variations between the characters that are being read and the standard characters.
However, it is difficult to provide an accurate monitoring system because of a number of "noise" sources, including variations in the orientation of paper (alignment of reader head with respect to image). Paper may skew as much as 5% and greater from the longitudinal axis of the paper path. Other noise sources affecting the monitoring include the speed of image transport across the head gap and calibration of output to a reference standard.
Knapp et al., U.S. Pat. No. 4,563,086, discloses an electrophotographic printing machine in which a magnetic toner image is transferred to a copy sheet. The image is magnetized and the intensity of the magnetic field generated by the toner image is detected to provide a continuous indication of the quality of image fused on the copy sheet. The magnetic field intensity is proportional to the ratio of the mass of toner particles to the area of toner particles on the copy sheet. The machine further includes means for comparing the intensity of the magnetic field detected by the detecting means. In response, a control signal is generated that regulates a processing station of the printing machine.
The present invention relates to a method and system for controlling the application of magnetic ink characters to a substrate. The method comprises generating an electrical signal representative of a test magnetic ink character display, comparing the integral representation with the integral representation of a predetermined magnetic ink display, and adjusting the application of magnetic ink characters to a substrate according to the comparing step. The generating step may comprise applying a test magnetic ink character display to a substrate, reading the magnetic ink character display as the substrate passes a read element, and generating the electrical signal representative of the display. The application of a magnetic ink character display to a substrate in, for example, an electrostatographic printing process, may be adjusted in response to the comparing step.
One embodiment of the invention comprises applying the predetermined magnetic ink character display to a substrate, reading the predetermined magnetic ink character display as the substrate passes a read element, generating an electrical signal representative of the predetermined magnetic ink character display, and converting the electrical signal of the predetermined magnetic ink character display to the integral representation.
The test magnetic ink character display and the predetermined magnetic ink character display may be applied side by side on a substrate. Each display may comprise a plurality of imaged lines. Each of the plurality of imaged lines of the test magnetic ink character display may be imaged alternately among each of the plurality of imaged lines of the predetermined magnetic ink character display with each of the plurality of test image lines adjacent one of each of the plurality of the standard imaged lines.
An electrical signal from each of the plurality of imaged lines of the predetermined magnetic ink character display may be compared to a reference integral representation. The comparing step may comprise separately adding the test and reference integral representations and comparing the sum of the test integral representations with the sum of the reference integral representations. The application of magnetic ink characters is adjusted according to the difference between the sums. The displays may alternate side by side and the signals are divided into test signals and into reference signals depending upon the order received.
Each of the integral representations from the test display may be compared to the integral representation from an adjacent reference display to give a compared value. The compared values may be added and the application of magnetic ink characters adjusted according to the sum of the compared values.
Further, the invention relates to a magnetic ink character recognition system, ,comprising a reader for detecting magnetic flux generated from a magnetic character and outputting an electrical signal representative of the magnetic flux and a comparator operatively connected to the reader for comparing an integral signal of the electrical signal of the magnetic character to the integral representation of a signal from the standard magnetic ink character. The system may be a self-contained magnetic ink character recognition device and may comprise a generator responsive to the comparator for generating a control signal to regulate a processing station of an electrostatographic printer. Or the system may be part of an electrostatographic printing system.