JPS5959478A - Abnormal print detection system - Google Patents

Abstract

PURPOSE:To detect abnormal print accurately according to purpose of utilizing print results by performing the detection of abnormal print depending on a print error pattern in a specified surface area in a laser printer. CONSTITUTION:A dot pattern preparation circuit 3 converts printing information stored in a print buffer 1 into a binary pattern corresponding to a print surface pixel with a character generator 2 to be outputted in series and modulates a laser beam with a laser modulator 4. A binary signal is detected with a detector 5 from outputs of a modulator 4 and compared with a binary pattern from the dot pattern preparation circuit 3 by a comparator 6. Then, a print error pattern corresponding to five continuous scanning lines in a raster scan of the laser beam are memorized temporarily into a register 7 and a surface area of 5X5 dots is memorized temporarily into a matrix memory 8 to be compared with a judging reference S corresponding to utilization purpose using a decision logic 9. Thus, the detection of abnormal print can be performed accurately according to the purpose of utilizing print results or the like.

Description

Detailed Description of the Invention (A) Technical Field of the Invention The present invention relates to a method for detecting abnormal printing in laser printers. It is widely used for commercial purposes, especially as an output device for large-scale computer systems for Japanese language processing.

However, abnormal printing is likely to occur, such as falling dots or dirt due to noise, which were not present in conventional impact type line printers.Therefore, accurately detecting all such abnormal printing is an important technical issue. It has become.

(C) Prior Art and Problems Laser printers generally include a print buffer that stores print information, a character generator that stores basic patterns such as individual character reference figures constituting the print information as binary patterns in pixel units, and a character generator as described above. The system is equipped with a dot pattern creation circuit that uses a character generator to convert print information into a binary pattern corresponding to the pixels on the printing surface and outputs it in series, and a laser modulator that modulates a laser beam using the output of the dot pattern creation circuit. Conventionally, error detection was performed using methods such as parity checks for the transmission and reception of No. 48 between the print buffer, character generator, and dot pattern creation circuit, but the laser variable temperature filter has a new method. For this reason, there was no layered detection of errors in printing + W-reporting.

As mentioned above, abnormal printing such as missing or adding dots is likely to occur in laser printers, but for example, even if one dot is dropped or added to a character pattern, there is no problem in practical use. . Furthermore, there is often no problem even if a width of one dot is dropped or added continuously in the scanning line direction or the sub-scanning direction. However, if this occurs in a planar manner in both the scanning line direction and the sub-scanning direction, it often becomes a problem.

(D) Object of the Invention The present invention has been made in full view of the problems in the prior art described above, and it is an object of the present invention to provide a means for detecting abnormal printing occurring in laser printers over the entire surface.

(E) Structure of the invention, that is, the abnormal printing detection method according to the present invention includes a dot pattern creation circuit that converts print information into a binary pattern and outputs the binary pattern in series in correspondence with the 1illii patterns constituting the printing surface; The laser printer is equipped with a laser modulator W and a delta modulator that modulates a laser beam by the output of a pattern creation circuit, and prints the printed information as an all-dot pattern by scanning the laser beam output from the laser modulator as a whole dot pattern. and a comparator that detects a discrepancy between the output edge of the laser modulator corresponding to the binary pattern, and
a matrix memory for temporarily storing a part of a surface area in a print error pattern obtained as an output of the comparator corresponding to a plurality of consecutive running hill lines; and a print error pattern temporarily stored in the matrix memory and a predetermined print error pattern. A determination logic that performs a comparison with a determination standard is provided, and abnormal printing is detected based on the print error pattern of the predetermined surface area.

(F) Embodiments of the Invention Below, the gist of the present invention will be specifically explained with reference to fully illustrative embodiments.

FIG. 1 shows a configuration diagram of an embodiment of the present invention, in which 1 is a print buffer that stores print information, and 2 is a basic pattern of individual characters, figures, etc. that constitutes all print information, and is stored as a binary pattern in units of all pixels. 3 is a dot pattern generation circuit that uses the character generator 2 to convert the print information stored in the print buffer l into a binary pattern corresponding to the pixels on the printing surface and outputs the same in series; 4
5 is a detector that detects a binary signal from the output of the laser modulator 4; and 6 is a binary pattern converted in the dot pattern creation circuit 3. A comparator that detects all discrepancies between the output of the detector 5 and the output of the detector 5 corresponding to the binary pattern, and a print obtained as the output of the comparator 6 corresponding to five consecutive scanning lines in the rask scan of the seven-digit laser beam. A register 8 temporarily stores the error pattern; a matrix memory 8 scans from left to right a surface area of 5×5 dots in the print error pattern temporarily stored in the register 7 and sequentially temporarily stores the pattern; 9 a matrix memory 8; This is determination logic that compares the temporarily stored print error pattern with a predetermined determination criterion S.

With the above configuration, the print error patterns corresponding to the five scanning lines are temporarily stored in the register 7KI@next, and the matrix memory 8 stores the print error patterns corresponding to the five scanning lines.
Abnormal printing can be detected by constantly monitoring the error pattern within the five-dot surface area and using the determination logic 9.

FIGS. 2(a), 2(b), and 2(c) respectively show examples of the contents of the contents matrix memory 8 of the register 7 and the criterion S, in which print errors are assigned a value of "1".

The pattern used as the judgment criterion S can be any pattern within 5 x 5 dots depending on the purpose of using the print result, but in the example of Fig. 2, the register 7
Since there is no pattern such as (C) in which all 3×3 dots are "1" among the print error patterns stored in the print error pattern, the determination logic 9 does not generate an abnormal printing detection signal.

(G) As described in detail of the invention, according to the present invention, it is possible to monitor the entire area of abnormal printing such as dropping or addition of dots in a laser printer, so detection of abnormal printing can be used for purposes such as utilization of printing results, etc. This can be done accurately depending on the situation.

[Brief explanation of the drawing]

FIG. 1 shows a block diagram of an embodiment of the present invention, in which 1 is a dot pattern generation circuit, 4 is a laser modulator, 6 is a comparator, 8 is a matrix memory, and 9 is a determination logic. Furthermore, FIG. 2 is an explanatory diagram of the operation of one embodiment of the present invention. Figure 1 Figure 2 (α)

Claims (1)

[Claims] A dot pattern creation circuit that converts printing information into a binary pattern corresponding to pixels constituting a printing surface and outputs the same in series, and a laser modulator that modulates a laser beam using the output of the dot pattern creation circuit, In a laser printer that prints print information as a dot pattern by scanning a laser beam output by a laser modulator, a comparator detects a mismatch between the binary pattern and the output of the laser modulator corresponding to the binary pattern. a matrix memory for temporarily storing a part of a surface area of a print error pattern obtained as an output of the comparator corresponding to a plurality of consecutive embroidery patterns; and a print error pattern temporarily stored in the matrix memory. What is claimed is: 1. An abnormal printing detection method, comprising: determination logic that performs comparison with a predetermined determination standard, and abnormal printing is detected based on a print error pattern in the predetermined surface area.