Contents Bar Code Made Easy 1 What is a bar code?.......................................... 1 Which bar code type should I use?............................... 2 How are bar codes read?....................................... 3 How can I avoid reading unwanted bar codes?...................... 3 How does Kodak merge bar code reading with microfilming to create a complete document record?................................... 4 Kodak Imagelink Microimager 70.............................. 4 All other scanner products.................................... 5 How do I place bar codes on my documents?....................... 6 Bar code labels............................................ 6 Bar codes printed directly on documents......................... 6 Can I use dot matrix generated bar codes?......................... 6 Bar code specifications........................................ 7 Where can bar codes be positioned on my documents?............. 7 What are the required dimensions for my bar code?.................. 8 What are the print quality requirements for my bar codes?............. 9 How do I know my bar codes will work?........................... 10 How can I monitor my system s performance?.......................11 Appendix A Glossary..........................................A-1 Appendix B Bar code data transmission specifications..............b-1 A-61099 October 1997 i
Bar Code Made Easy This publication refers to all Kodak Digital Science and Imagelink Scanners and Microimagers. These products include the Kodak Imagelink Microimager 70, Kodak Imagelink Scanner 500, 900, 923, Scanner/Microimager 990, and Kodak Digital Science Scanner 5500, 7500, 7550, 9500 and Scanner/Microimager 990. What is a bar code? Bar coding is a method of encoding data in a machine-readable code consisting of a parallel arrangement of dark and light elements. The light elements are referred to as spaces and the dark elements as bars. The bars and spaces are either wide or narrow. The combination of wide and narrow bars and spaces is a bar code. Each bar code begins with a start character and ends with a stop character. The industry uses bar codes to provide more accurate and efficient data input than is possible using manual data entry. Code 3 of 9 Code 3 of 9, also called Code 39, is a widely used code in which nine bars or spaces comprise the characters, of which three of the bars or spaces are wide. Interleaved 2 of 5 Interleaved 2 of 5, also called I 2 of 5, is a compact, interleaved code for numeric characters only. Each digit is represented by five spaces, two of which are wide. Codabar Codabar is similar to Code 3 of 9, but it is not widely used. Codabar includes only numeric and special characters. A-61099 October 1997 1
Which bar code type should I use? It is recommended that you use Code 3 of 9. However, use the following factors to determine the type of bar code to use for your applications: Character types if your applications require alphabetic characters, Code 3 of 9 must be used. Interleaved 2 of 5 and Codabar are limited to encoding only numeric characters. Length (comprised of the number of characters in a barcode) requirements if your applications require bar codes of differing lengths, Code 3 of 9 should be used. Interleaved 2 of 5 and Codabar require all bar codes to be a fixed length; and the application mode must be programmed for that exact length. Reliability of start character recognition the reliability of start character recognition when using Code 3 of 9 is significantly higher than when using Interleaved 2 of 5. Space constraints if your applications have space constraints which impose a limit on the length of the bar codes used, Interleaved 2 of 5 should be used. The amount of space required for an Interleaved 2 of 5 code is half the amount of space required to encode the same information in Code 3 of 9. The Comparison of bar code types presented below indicates the factors which may impact your decision. Comparison of bar code types Code Type Character Set Available characters in the set Start/Stop characters Percentage of users Code 3 of 9 alphanumeric space special characters: -. $ / + % 43 * / * 80% Interleaved 2 of 5 numeric 10 both unique 17% Codabar numeric special characters: - $ 12 a / a-d 3% 2 A-61099 October 1997
How are bar codes read? Bar codes are read by a scanner. The most commonly used scanner is the infrared (I.R.) laser. Laser scanners are categorized into two types: fixed beam and moving beam. Fixed beam scanners are typically handheld wands which must be manually moved across the bar code. Moving beam scanners use a mirror to sweep the beam across a bar code. The Kodak Imagelink and Digital Science Bar Code Readers use a bar code scanning technology, called CCD (Charged-Coupled Device), incorporating an efficient fluorescent visible light source integrated with a state-of-the-art CCD sensor. The CCD scanner electronically captures the entire width of a document image and decodes all bar codes within the document. The visible light source allows bar codes to be printed with any ink type. Scanner types comparison Bar Code Ink CCD Laser Bar code ink No restrictions Requires carbon-based ink Scan window width 11 inches (305 mm) often limited to 4-6 inches (102-253 mm) Scan method Electronic (CCD) Mechanical moving mirror (moving beam) How can I avoid reading unwanted bar codes? Many applications include bar codes from other companies, other applications, etc. (i.e., accounts payable). You can effectively screen out unwanted bar codes: Each application mode is programmed to read a specific bar code type. All other bar code types will automatically be screened out. If the unwanted bar codes are the same type as the bar code(s) you want to read, there are two ways of screening out the unwanted bar codes: - If the bar code you want to read always appears first on the document, the application mode may be programmed to read only the first bar code encountered. - If the bar code(s) you want to read has more characters than the unwanted bar code(s), the application mode may be programmed to reject any bar code which has less than a specified number of characters. A-61099 October 1997 3
How does Kodak merge bar code reading with microfilming to create a complete document record? Kodak Imagelink Microimager 70 The Kodak Imagelink Bar Code Reader is an accessory to the Kodak Imagelink Microimager 70. This system reads the bar code data, merges the data with the unique image address assigned to the document, and transmits the data record to the host computer for storage in a data library. 4 A-61099 October 1997
All other scanner products The Kodak Imagelink Bar Code Reader is an accessory to the Kodak Digital Science Scanner 9500, as well as the Kodak Imagelink Scanner 500, 900, 923, Scanner/Microimager 990, and the Kodak Digital Science Scanner/Microimager 990. The Kodak Digital Science Bar Code Reader also is available as an accessory to the Kodak Digital Science Scanner 5500, 7500, and 7550. This system reads the bar code data, incorporates the data in an image header, and transmits the image header and document image to the host computer. A-61099 October 1997 5
How do I place bar codes on my documents? Bar code labels Bar codes printed directly on documents You can place bar codes on documents by affixing bar code labels to the documents or by printing bar codes directly on the documents. Both labels and preprinted documents can be created either in-house or by an outside vendor. Bar code labels are widely used on incoming mail applications such as accounts receivable, accounts payable, order entry, correspondence, and claims. Bar code labels can be preprinted by many printing vendors or printed in-house using a bar code label printer. Labels which have been preprinted by a printer are most likely to be used for high-volume applications with sequentially numbered bar codes. In-house labeling is commonly used in document-specific applications where the bar code data is assigned during document processing; for example, credit card applications are assigned bar coded account numbers after initial screening. Bar codes are printed directly on documents by an outside printing vendor in sequential order for high-volume applications such as freight bills and traffic tickets. In-house printing of bar codes directly on documents is used when the application calls for nonsequential, document-specific barcodes printed on demand at remote or central locations. Examples of an application using this requirement are trucking companies which print bills of lading with descriptive shipment bar codes (i.e.,vin numbers) at remote terminal locations with common dot matrix printers. Can I use dot matrix generated bar codes? In most systems, dot matrix codes reduce a system's performance. However, Kodak has developed an image enhancement process to electronically correct some of the dot matrix deficiencies. This process is included in all Kodak Imagelink and Digital Science Bar Code Readers and is programmable for enhancement of dot matrix bar codes with narrow element widths of 0.020 inches (0.51 mm) or greater. 6 A-61099 October 1997
Bar code specifications Where can bar codes be positioned on my documents? A B C D E F Top edge: The minimum distance from the top edge of the document to the top edge of the bar code is 0.25 inches (6.35 mm). Bottom edge: The minimum distance from the bottom edge of the document to the bottom edge of the bar code is 0.25 inches (6.35 mm). Quiet zone: A blank area of 0.25 inches (6.35 mm) should precede the start character and follow the stop character. Stacked codes: If a page contains stacked bar codes, the vertical distance between the two bar codes must be equal to or greater than the bar code height of the tallest bar code. Multiple codes: If a page contains multiple bar codes, only one code can be positioned in each line. The Kodak Imagelink and Kodak Digital Science Bar Code Reader may be programmed to read all codes or only the first code detected. Encoded characters per document: The maximum number of encoded characters per document is 80 characters for an 11-inch (280 mm) document. Skew: The maximum amount of skew allowed is 5. This includes the amount of bar code skew (the amount of variation in the placement of the bar code on the document) and the amount of document skew (the amount of variation which occurs when feeding the document into the transport). A-61099 October 1997 7
What are the required dimensions for my bar code? The following dimensional specifications must be followed when printing bar codes on documents or printing bar code labels. The specifications apply to all bar code types, except where noted. A Code length: The maximum bar code length is 11 inches (275 mm) on white paper with a reflectance of greater than 75%. The maximum bar code length is 9 inches (230 mm) on paper with a reflectance of 50 75%.There is no fixed minimum bar code length; the minimum length is a function of the type of bar code used and the minimum number of characters allowed. The minimum number of characters per bar code is 3 or greater for both Code 3 of 9 and Codabar. The minimum number or characters per bar code is 6 or greater for Interleaved 2 of 5. The minimum number of characters does not include the start and stop characters. B Code height: The minimum bar code height is 0.375 (3/8) inches (9.5 mm) or 25% of the bar code length, whichever is greater. The maximum bar code height is 3.0 inches (75 mm). C Narrow-element width: The minimum narrow-element width is 0.010 inches (0.25 mm). The maximum narrow-element width is 0.066 inches (1.65 mm). D Wide-element width: The minimum wide-element width is 0.022 inches (0.55 mm). he maximum wide-element width is 0.200 inches (5 mm). E Wide-to-narrow ratio: The minimum wide-to-narrow ratio is 2:1 if the minimum narrow element width is greater than 0.020 inches (0.51 mm). The minimum wide-to-narrow ratio is 2.2:1 if the minimum narrow element width is less than or equal to 0.020 inches (0.51 mm). F Intercharacter gap: The intercharacter gap must be 1 to 3 times the minimum narrow element width. There is no intercharacter gap in Interleaved 2 of 5 bar code. 8 A-61099 October 1997
What are the print quality requirements for my bar codes? Your bar code reader's performance is dependent upon the quality of your bar codes. Poor quality codes will not produce optimum results. ANSI has published guidelines for Bar Code Print Quality (ANSIX3.182-1990). These guidelines establish letter grades (A F) which represent overall print quality. A grade bar codes are excellent and will produce optimum results. Grade B and C barcodes will reduce the performance of the system. Grade D F bar codes are likely to cause poor performance. The standard set of bar codes you receive with your Bar Code Reader Accessory should give you at least B grades. If you get a C grade or lower, check your imaging equipment. If you get B grades with the Kodak Bar Code Documents, and get C or D grades with customer documents, check the customer documents for the cause. Overall print quality is determined by dimensional and reflectance criteria. Dimensional criteria are based upon actual linear measurements. Reflectance criteria are measures of print consistency. Dimensional Criteria Factor Description Cause of Poor Grade W/N Wide-to-Narrow ratio Bar codes not printed according to specifications (refer to What are the required dimensions for my bar code? ) NEW A ratio calculated by dividing the average wideelement width by the average narrow-element width. Inaccurate measurements: ink smearing (improper curing) Two calculations are performed: one for bars and one ink spreading (super-absorbent paper) for spaces. The smallest of the two calculations is the use of dot matrix printers (ragged edges) Wide-to-Narrow Ratio. NEW Minimum Narrow-Element Width A measurement of the smallest narrow-element width in the bar code (bar or space). A-61099 October 1997 9
Reflectance Criteria Factor Description Cause of Poor Grade Contrast Symbol Contrast A = 100-70% A percentage calculated by determining the reflectance value of all elements in a bar code (bars and spaces) and then subtracting the smallest reflectance value (belonging to the darkest element) from the largest reflectance value (belonging to the brightest element). Bar elements are too light: use of an old ink ribbon hammer pressure too light defective/dirty print head Space elements are too dark: dark colored paper background stain on paper MOD Modulation A = 100-70% A percentage calculated by dividing the smallest edge contrast (defined below) by the symbol contrast (defined on the previous page). Edge contrast is calculated by subtracting the reflectance value of a bar from the reflectance value of the adjoining space. This calculation is performed for each bar/space pair and the smallest value (indicating the least amount of reflectance difference) is the smallest edge contrast. DEF RMIN Defect Ratio A = 0-15% A percentage calculated by dividing the maximum element reflectance non uniformity defined below) by the symbol contrast (defined on the previous page). Element reflectance non uniformity is calculated by subtracting the lowest reflectance value found in a single element from the highest reflectance value found in the same element. This calculation is performed for each element of the bar code (bars and spaces) and largest value (indicating the largest amount of reflectance difference) is the maximum element reflectance non uniformity. Minimum Reflectance A = 0-49% A percentage calculated by determining the reflectance value of all elements in a barcode (bars and spaces). The smallest reflectance value of any element in the barcode (belonging to the darkest element) is the minimum reflectance. Bar code element edges are ragged rather than straight (often caused by dot matrix printer): Minimum narrow-element width too small Bar elements contain voids (white spots): use of old ink ribbon hammer pressure too light defective/dirty print head Space elements contain dark spots: paper contains flecks defective/dirty print head ink smearing (improper curing) ink spreading (super-absorbent paper) toner contamination (using a laser printer) Bar elements are too light: use of old ink ribbon defective/dirty print head Space elements are too dark: dark colored paper background stain on paper How do I know my bar codes will work? Contact your Kodak Service personnel for information about testing your bar codes. 10 A-61099 October 1997
How can I monitor my system s performance? The Kodak Imagelink or Digital Science Bar Code Reader includes a built-in performance monitoring function. The monitoring function consists of four separate tests which maybe performed by the operator: Option 1 Evaluate: This performance monitoring tool provides a measure of the overall quality of the bar codes being used by evaluating specific bar code characteristics in accordance with the ANSI Guidelines for bar code printing (refer to What are the print quality requirements for my bar codes? ). This test is performed whenever a new batch of preprinted bar code documents or labels is received, or when there is a change in the printing method (i.e., a new printer), media (i.e., new paper type), or bar code characteristics (i.e., new bar code length). Option 2 Display: This test displays the decoded value of an individual bar code as it is fed into the transport. This test is performed whenever there is a need to verify that the bar code is decoded properly. The bar code is read and decoded; no capturing of images or any other system function is performed when the test is run. Option 3 - % Kodak: This test benchmarks equipment performance by determining the read rate (percentage of bar codes read properly) of Kodak Bar Code Standard Test Documents. Each time the test is run a current percentage and a historical percentage are calculated. The historical percentage reflects all tests run, providing information which may be used to track system performance over time. Option 4 % Norm: This test benchmarks a measure of quality of the bar codes used by determining the read rate (percentage of bar codes read properly) of actual customer-application documents. Each time the test is run a current percentage and a historical percentage are calculated. The historical percentage reflects all tests run, providing information which may be used to track system performance over time. A-61099 October 1997 11
Appendix A Glossary Alphanumeric The presence of numeric digits (numbers) and alphabetic characters (letters) in the same character set. Bar The dark element(s) of a bar code. Bar code symbol A machine-readable code consisting of a parallel arrangement of bars and spaces. Bar length or bar height The measurement of the long, vertical dimension of a bar code. Bar width ratio The ratio of the widest to the narrowest bar width within a barcode. Character set Those characters available for encoding within the bar code symbology. Check digit A character included within a bar code symbol whose value is used for performing a mathematical check of the validity of the decoded data. Code density The number of characters per unit length. Contrast A comparison of the darkest and lightest elements of a bar code. Specifically, a percentage calculated by determining the reflectance value of all elements in a bar code (bars and spaces) and then subtracting the smallest reflectance value (belonging to the darkest element) from the largest reflectance value (belonging to the brightest element). Defect ratio (DEF) A measure of the consistency of print quality, which may be affected by the occurrence of spots (in spaces) and voids (in bars). Specifically, a percentage calculated by dividing the maximum element reflectance non uniformity by the Symbol Contrast. Edge contrast A comparison of the amount of reflectance of a bar element and the adjoining space element. Specifically, edge contrast is calculated by subtracting the reflectance value of a bar from the reflectance value of the adjoining space. Element A generic term referring to either a bar or a space. Elements are referred to as wide or narrow. Element width The measurement of the thickness or width of an element (bar or space). Element reflectance non uniformity A measure of the consistency of print quality of an individual barcode element (bar or space). Specifically, element reflectance non uniformity is calculated by subtracting the lowest reflectance value found in a single element from the highest reflectance value found in the same element. A-61099 October 1997 A-1
Intercharacter gap The space between the last element of one character and the first element of the next character. Minimum Narrow-element width (NEW) A measure of the smallest narrow-element width. Minimum reflectance (RMIN) A measure of the darkest element of the bar code. Specifically, a percentage calculated by determining the reflectance value of all elements in a bar code. The element with the smallest reflectance value (the darkest element) is said to have minimum reflectance. Modulation (MOD) A measure of the consistency of the overall bar code print clarity (all elements) and the sharpness of bar edge contrast. Specifically, a percentage calculated by dividing the smallest edge contrast by the symbol contrast. Quiet zone The area immediately preceding the start character and following the stop character which contains no markings. Reflectance A measure of the amount of light reflected back from a surface. Elements which appear to be dark have the lowest reflectance; elements which appear to be light have the highest reflectance. Space The light element(s) of a bar code (area between the bars). Start and stop characters Unique character codes used before and after bar code data characters which indicate the boundaries of the bar code symbol. Symbol Contrast See Contrast. Wide-to-narrow ratio (W/N) A ratio calculated by dividing the average wide-element width by the average narrow-element width. The ratio is calculated for both bars and spaces; the smallest of the two ratios is used for evaluation. A-2 A-61099 October 1997
Appendix B Bar Code data transmission specifications Bar code data read by a Microimager 70 with Bar Code Reader and Document Scanning Array is transmitted via an RS-232. Bar code data read by a Scanner 900, 923, 9500, and Scanner/ Microimager 990 with Bar Code Reader may be transmitted via SCSI or RS-232. RS-232 (Microimager 70, Scanner 900, 923, 9500, and Scanner/ Microimager 990) The data transmission is asynchronous at 9600 bits-per-second (baud) in accordance with EIA RS232C specifications. Data output is through a DB-25 female connector located on the back of the machine. The output is configured as a DTE device with the following pin assignments: Pin 1 Protective ground Pin 2 Data out Pin 7 Signal ground The data format is ASCII code, 8 bits-per-character, 1 start bit, 1stop bit and no parity. Bar code data is transmitted in the following format(s): The data record for a document with a single bar code would be: <Bar Code Data> : <Image Address> <Line Feed> The data record for a document with multiple bar codes would be: <Bar Code Data 1> ; <Bar Code Data 2> : <ImageAddress> <Line Feed> The data record for a document without bar codes or an unreadable bar code would be: <Image Address> <Line Feed> SCSI (Scanner 900, 923, 9500, Scanner/ Microimager 990; and Scanner 500, 5500, 7500, and 7550) The data transmission is initiated by the host system using the SCSI Read command. The data transferred is an Image Header which is created during the scanning process. The Image Header is a maximum of 512 bytes, consisting of a variety of information, including barcode information. For detailed information, refer to the appropriate Integrator s Guide: A-61034, Kodak Imagelink Scanner 900, 923, and Scanner/ Microimager 990 Integrator's Guide A-61071, Kodak Digital Science Document Scanner 5500 and7500 Integrator s Guide A-61091, Kodak Digital Science Document Scanner 9500 and Document Scanner/Microimager 990 A-61099 October 1997 B-1