JPS6298475A - Print quality inspection method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a print quality inspection method for inspecting the print quality of an output device such as a print printer.

[Background of the invention]

Printers, which are connected to computers and other systems as integrated system equipment and print out necessary information as hard copies, are rapidly becoming more and more expensive with the spread of word processors, pan controllers, and other office automation equipment. Quantification and its automation are urgently needed.

As a conventional method for inspecting print quality using printer output of this type, there is a method known as "Utilization of visual sensor in character inspection system" by Toshimi Kodaira of Sensor Technology VoL4N111 Fuji Electric.

As shown in these examples, according to the conventional printing quality inspection method, character distortion is determined by determining various feature quantities based on local information of a single character, so it requires a lot of effort. This required treatment.

[Purpose of the invention]

The present invention has been made in view of the problems in the prior art described above, and it is an object of the present invention to provide a print quality inspection method that can easily determine the print quality of an output device such as a printer by image processing.

[Summary of the invention]

The present invention has discovered that the cause of character collapse is the timing lag between paper feeding and printing in the paper feeding drive system of the output device, and has developed a method for inspecting this skew that is simpler and larger than a single character. It was determined that evaluation using a specific pattern would make imaging for quality inspection easier and processing easier. Therefore, the present invention is characterized in that the pattern is a specific pattern such as a rectangle, and the lengths of the sides in the X and y directions are measured and compared with specified values for evaluation.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an overall system configuration diagram to which the printing quality inspection method of the present invention is applied, in which 1 is a hard copy paper printed out from an output device such as a printer, 2 is a hard copy paper above the hard copy paper 1 3 is an image processing device; 4 is a transparent inspection table on which the hard copy paper 1 is placed; 5 is a transmitted light located below the transparent inspection table 4;
6 is a monitor.

According to the system configuration shown in FIG. 1, the output pattern 1a, such as a rectangle, output on the hard copy paper 1 is imaged by the Tl/camera 2, and the input image is processed by the image processing device 6! The configuration is such that the print quality of the printer is inspected by measurement processing, for example, by measuring the lengths of the sides of the output cover pattern 1a in the x and y directions and comparing them with preset standard values. If the print quality is poor, this can be done by adjusting the feed speed of the paper feed drive system (not shown) and adjusting the print timing to eliminate timing deviations.

Here, the hard copy paper 1 is placed on a transparent inspection table 4 such as a plastic plate, and the inspection table 4 is illuminated by transmitted illumination 5.
It is illuminated from the back side (from below in the figure). Then, an area sufficiently including the output cover pattern 1a is imaged from the normal direction of the notebook copy paper using the TV camera 2, and the captured image is processed by the image processing device f3 as shown in the flowchart of FIG. process. The state of the processing is output to monitor B.

FIG. 2 is a plan view of the hard copy paper 1 shown in FIG. This is done by measuring 1x, l.

This output width 1', , 1. By comparing the length with a predetermined standard value, it is possible to determine whether the timing of feeding the hard copy paper 1 in the printer and printing in response to it is appropriate, and also to prevent the printed characters from becoming distorted. It can be determined whether or not this occurs.

Next, the process of processing the captured image will be explained according to the flowchart of FIG. As shown in the figure, a target image is input (captured with a TV camera) in step S1, and the image is binarized using an appropriate threshold value in step S2. Approximate the outline of the pattern of the binary image into polygons (line segmentation) using AS3 and create a row of vertex data (each 1).

``fit i = 1', 2-n) is determined, and in step 84.85, four points corresponding to points A, B, C:, and DK of the output pattern 1a in FIG. 2 are selected from the data. First, The coordinate position (XA, YA) of point A is the origin (o
, o) is the upper left corner of the TV screen (indicated by a broken line), so it can be found by selecting the nearest point from the line segmentation data.

Similarly, the coordinates of points B, C, and D are determined in step S5. Then, from the four points obtained in step 84.35, step S6
The output width is 1. ．． 1. is calculated and compared with a specified value in step S7 to determine whether or not the printer's printing state has been adjusted properly.

〔Effect of the invention〕

As is clear from the above-described embodiments, according to the present invention, a specific pattern such as a rectangle is printed from an output device such as a printer, imaged by a TV camera, and inputted to an image processing device. By approximating the outline of the specific pattern to a polygon, detecting the corner coordinates, and calculating the length of the sides of the specific pattern, the operation of the drive system that feeds the paper of the output device and the timing of printing are judged to be good or bad. This has the advantage that deformation of printed characters such as output characters can be determined with high precision, and high quality output printing can be obtained.

[Brief explanation of drawings]

Figures 11 to 4 are diagrams for explaining one embodiment of the present invention, in which Figure 1 is an overall system configuration diagram for explaining the print quality inspection method, and Figure 2 is a hard copy of the printed output. The plan view of the sheet, FIG. 3, is a flowchart 1 of the calculation process of the image processing apparatus in FIG. 1...Hard copy paper 1a...Output pattern 2...TV camera 3...Image processing device 4...Inspection table 5... ...Transmitted illumination 6...Monitor

Claims (1)

[Claims] In a method for inspecting the print quality of an output device such as a printer, a specific pattern such as a rectangle is printed out from the output device, imaged by a TV camera, and inputted to an image processing device, and the image processing device prints the specific pattern. Print quality inspection that determines whether the drive system of the output device is operating properly and evaluates the print quality by approximating the contour of the image to a polygon, detecting the corner coordinates, and calculating the side length of the specific pattern. Method.