JPS5942357B2 - Character pattern error check method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for checking the occurrence of erroneous character patterns in a printer control device.

For printers, garbled print is a fatal defect. Conventionally, in impact printers, the rate of printing errors has been considered unavoidable to some extent. On the other hand, non-impact printers such as laser printers have an extremely low possibility of printing errors due to their raster scanning method. However, in order to provide flexibility, such printer control devices often use small processing devices such as minicomputers, so error checking is difficult.
This is performed by either or both of the data system parity check used in conventional processing devices and the program check at the single instruction level of the processing device. but,
With such a parity check or a single-instruction level grammatical check, there will be cases where the check cannot be completed. Accordingly, the parity check cannot check for 2-bit errors, etc., and the instruction level check only checks for inconsistencies in a single instruction, so if the parity check is mistaken for an instruction with a format inconsistency, It takes a while to check, but if you make a mistake with an instruction that has a compatible format, the check will not work and the result will be incorrect printing, which will cause a serious problem for the printer, and the impact will be great. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for checking the occurrence of erroneous character patterns in a control device such as a non-impact printer, and in particular, to provide a check method that is easy to implement, powerful, and highly reliable. It is in.

A control device such as a non-impact printer generally has a memory that stores all nine character patterns that can be generated in the device, a font memory that stores frequently used characters, and a character pattern in each memory. It has table memory for finding storage addresses and code conversion table memory.

Most character patterns are determined from the font memory by drawing the code conversion table memory. Therefore, the normality of the contents of the code conversion table memory and font memory is very important. The present invention adds a unique code to each character pattern and stores it in memory in advance, and combines the character code given from outside the device and the unique code added to the character pattern read from the memory in accordance with the character code. The normality of the code conversion table and the character pattern storage memory, that is, the validity of the generated character pattern, is checked by comparing the characters with the comparison means. Next, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a simplified block diagram showing only the essential parts of an embodiment of a printer control device according to the present invention.

In the figure, 1 is a character code register, 2 is a control circuit for controlling the generation of character patterns, 3 is a code conversion table, 4 is a character pattern memory, 5 is a comparison circuit, and 6 is an editing memory. The character pattern memory 4 stores character patterns for each character code, for example, 3 as shown in FIG.
Although it is stored as a 2-bit x 32-bit bit pattern, the corresponding character code (2 bytes) is also added and stored.

Next, the operation will be described. A character code (for example, a kanji code) received from the outside is input to the control circuit 2 via the character code register 1. The control circuit 2 indexes the code conversion table memory 3 according to the character code sent from the outside, and checks whether the corresponding character pattern is registered in the character pattern memory 4. If it is registered, the address of that character pattern in the character pattern memory 4 is determined. Since such a method is a well-known technique implemented in conventional printer control devices and cache memory address conversion, it will not be described further.
The character pattern memory 4 is read out using the character pattern address obtained in this way. The first two bytes of the character pattern thus read out, that is, the character code, are led to the comparison circuit 5. The comparison circuit 5 compares the character code from the outside with the character code sent from the character pattern memory 4, and determines whether or not the two match. If a mismatch is detected, it is determined that it is an error and an error report is sent to the control circuit 2. If there is no abnormality in the check result (if a match is found), the data read out from the character pattern memory 4 following the character code, that is, the character pattern, is allocated to the editing memory 6, and page editing processing is performed. The page editing process is an operation of accessing the character pattern memory 4 to take out character patterns according to character codes and arranging them on the editing area according to the bit pattern of the output image, and is executed according to instructions from the control circuit 2. The page pattern edited on the editing memory 6 (an example of which is shown in FIG. 3) is output to the printer for each raster (one dot line in the horizontal direction of the paper). Note that even if a bit error occurs when writing a character pattern in character units to the editing memory 6 and reading dot data in raster order, it will only result in a defect in a part of the character, and the worst case of garbled printing will occur. It cannot become a situation.

Therefore, if the normality of the data up to writing to the editing memory is checked by the checking method of the present invention, there is almost no possibility of garbled printing. In other words, an incorrect character pattern will not be printed. As described above in detail, according to the present invention, garbled print can be reliably prevented.

However, the present invention also has the advantage of being extremely easy to implement.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing only the essential parts of an embodiment of the present invention;
Figure 2 is a diagram showing an example of the bit configuration of character patterns and character codes stored in the character pattern memory in Figure 1, and Figure 3 is an example of a page pattern obtained in the editing memory in Figure 2. FIG. 1... Character code register, 2... Control circuit, 3... Code conversion taker, 4...
...Character pattern memory, 5...Comparison circuit,
6...Editing memory.

Claims (1)

[Claims] 1. In a printer control device that reads a character pattern from a memory according to a character code given from an external source and supplies it to a printer, a unique code is added to each character pattern in the memory, and a unique code is added to each character pattern in the memory. Errors in the character pattern are checked by comparing the character code added to the character pattern read from the memory by a comparing means. Check method.