TWI498222B - Method and device to inspect quality of printings - Google Patents

Description

Printing quality inspection method and inspection device

The present invention relates to a printing quality inspection method and inspection apparatus therefor, and more particularly to an inspection method and apparatus for automatically inspecting print quality on a print carrier.

Printing is used on a wide variety of products. Prints are sometimes a consumer product, such as books, magazines, pictures, and so on. Sometimes printed matter is the packaging, catalogue, promotion medium, etc. of other products. These prints must have excellent print quality to be available to those who need it.

Conventional techniques are used to facilitate the inspection of print quality and are typically printed at appropriate locations on the print carrier, such as the edge portions that will be cut. By checking the position and color of the color code, you can determine whether the color is correct and the position is accurate. In order to improve the efficiency of inspection, conventional techniques have been developed to automatically check the methods and equipment to eliminate obviously bad prints. However, conventional print quality inspection methods and devices do not provide a simple and reliable positioning tool, which results in a print quality inspection device that does not provide a correct inspection result, or is too complicated, resulting in increased costs.

SUMMARY OF THE INVENTION The object of the present invention is to provide a novel printing quality inspection method and inspection apparatus, which achieves the purpose of improving inspection accuracy through a simple and reliable positioning method.

The invention provides a printing quality inspection method and an inspection device for judging the printing quality on the printing carrier by inspection of the inspection pattern printed on the printing carrier. Wherein, the inspection pattern includes a synchronization pattern for synchronous control of the printing quality inspection device; an address pattern for indicating address information available for identification by the printing quality inspection device; and at least A set of color scales used to indicate color information that can be recognized by the print quality inspection device. The inspection pattern can be a continuous inspection pattern string. The color information can be a combination of primary color information or a combination of monochrome information. The monochrome information may be the color printed each time when the color separation printing is performed.

Accordingly, the print quality inspection apparatus of the present invention comprises: a body for carrying: an optical detector for detecting a synchronization pattern on a print carrier; and an image input device for capturing the print carrier And the inspection device is configured to determine the print quality on the print carrier according to the content of the inspection pattern captured by the image input device; and a mobile platform for moving in one direction The body is configured to cause the image input device to scan the print carrier. The inspection device corrects the inspection pattern according to the detection result of the synchronization pattern; and the inspection device determines the print pattern address on the print carrier according to the content of the inspection pattern.

Accordingly, the printing quality inspection method of the present invention includes the steps of: detecting a synchronization pattern on the print carrier by the optical detector, and outputting a synchronization signal; and continuously capturing the print carrier on the print carrier Detecting the pattern, and digitizing the inspection pattern; determining the address information contained in the verification pattern according to the digitized inspection pattern; and extracting the digital inspection pattern captured by the image input device Color information, including each of its monochromatic information; determining whether the monochrome printing quality is within a qualified range according to the monochrome information contained in the color information; determining the monochrome printing according to the relative position of the monochrome area contained in the color information Whether the position is in the qualified range; and outputting the inspection result, including the address information, the printing quality inspection result and the printing position inspection result. The step of qualifying the printing quality may include comparing the monochrome information with a pre-stored monochrome information, determining the difference value, and determining that the difference value is within a threshold value. Wherein, the eligibility determining step of the printing position may include comparing a monochrome printing position with an adjacent monochrome printing position, calculating the difference, and determining that the difference is within a threshold value, and determining that the difference is acceptable. The determining step of the monochrome printing position may include: capturing a monochrome printing area, determining an edge line of the monochrome printing area, and using an edge line component along the direction in the edge line as the printing position thereof . The step may further include, as the print position, the edge line component in the opposite direction of the direction along the edge line. The method can include Continue the inspection process to perform the continuous inspection step.

Hereinafter, several embodiments of the printing quality inspection method and inspection apparatus of the present invention will be described based on the drawings. The detailed description of the present invention is merely illustrative of the principles, applications, and functions of the present invention, but the scope of the present invention should not be limited to the methods, steps, devices, systems or systems of the embodiments. Its components. The patent scope of the present invention can only be determined by the description of the scope of the patent application.

10‧‧‧ inspection pattern

20‧‧‧Printing carrier

11, 11‧‧‧ synchronous pattern

12, 12‧‧‧ address pattern

12a‧‧‧ Address Synchronization Pattern

12b‧‧‧ address information pattern

12c‧‧‧ digital pattern

13‧‧‧ color mark pattern

13a, 13b, 13c, 13d, 13e‧‧ ‧ color standard

100‧‧‧ body

110‧‧‧Light source

120‧‧‧ Optical detector

130‧‧‧Image input device

140‧‧‧Inspection device

150‧‧‧Mobile platform

Fig. 1 shows an example of a test pattern suitable for use in the present invention.

Fig. 2 is a view showing the system of the printing quality inspection apparatus according to an embodiment of the present invention.

Figure 3 is a flow chart of the printing quality inspection method of the present invention.

The invention provides a printing quality inspection method and an inspection device for judging the printing quality on the printing carrier by inspection of the inspection pattern printed on the printing carrier. Among them, the "test pattern" is one of the focuses of the present invention. Therefore, the inspection pattern will be described first.

Fig. 1 shows an example of a test pattern suitable for use in the present invention. As shown, in such an embodiment, the inspection pattern 10 can be a pattern printed on any print carrier 20. The print carrier 20 may include any object that carries a printed pattern, and thus may be paper, a flexible material such as a stretch of plastic, rubber, resin, etc., a metal foil, a woven fabric, a composite material, etc., or may be a hard material, such as Plane or three-dimensional objects such as metal, wood, plastic, rubber, resin, minerals, ceramics, glass, etc., as long as they can print graphics on them. However, the printing quality inspection method and inspection apparatus of the present invention are particularly suitable for use on an extended print carrier for rapid and extensive automated inspection of print quality including multi-array print patterns. Accordingly, the print carrier 20 is preferably an extended print carrier. It is not limited to printing a set of printed patterns over an extended unit length. Of course, these features are not technically limiting.

The test pattern 10 is generally printed on the print carrier 20 when a pattern (not shown) is printed on the print carrier 20. In other words, a pattern is printed on the print carrier 20 At the time, it is based on color separation printing. That is, in a plurality of printing plates, a non-monochrome (without white) pattern of a single color is printed each time through a plurality of steps. The so-called single color can be a general (optical or display) color called "primary color". That is, red, blue, green, or red, yellow, and blue. It can also be used to print a variety of monochrome colors according to specific needs. In the following description, it will be referred to as "primary or monochrome" or collectively as "monochrome".

In the above case, the inspection pattern 10 is printed on the print carrier 20 with the respective monochrome printed on the print carrier 20. Specifically, the inspection pattern 10 includes a plurality of synchronization patterns 11, 11 which are represented by black squares in the figure; a plurality of address patterns 12, 12 are used to indicate address information, including address information of the inspection pattern 10; The majority of the color mark patterns 13 include black marks 13a and other monochrome color marks 13b, 13c, 13d, 13e, etc., and each of the color mark patterns 13a-13e is usually printed in the case of color separation printing (including black). Color code pattern. The figure shows that each set of inspection patterns 10 may include a plurality of synchronization patterns 11 and may also include more than one set of address patterns 12 and color mark patterns 13. In the embodiment shown in FIG. 1, the inspection pattern 10 includes two sets of address patterns 12 and color mark patterns 13. However, the number of address patterns and color mark patterns included in each group of inspection patterns is not a technical limitation. The address pattern 12 and the black mark in the color mark pattern 13 can be simultaneously printed, if the address pattern 12 is represented by black. However, if it is a combination of other colors or colors, it depends on its color.

The position of the sync pattern 11 and the position of the color patch pattern 13 or the address pattern 12 do not necessarily form any correlation. The function of the synchronization pattern 11 is to initiate a test once. However, in the present invention, the test material for a single test starts from the address pattern 12. Therefore, the timing of the start-up and the starting position of the test data need not be relevant. If the sync pattern 11 is also printed in black, it can be printed simultaneously with the black mark 13a. However, if it is a combination of other colors or colors, it depends on its color. In design, the shape, color and format of each color mark 13a-13e should be predetermined in advance for inspection. Preferably, the color patches 13a-13e are closely and continuously arranged in a certain order to correctly recognize the relative positional relationship therebetween. But arranged and combined in different ways is not forbidden. Basically, as long as the computer can correctly recognize its color, shape and relative positional relationship.

The address pattern 12 is preferably a pattern that can be automatically recognized by a computer, so that the print quality inspection device can recognize the address information it represents. In the embodiment of FIG. 1, the address pattern 12 includes a address synchronization pattern 12a, an address information pattern 12b, and a digital pattern 12c. The address synchronization pattern 12a is used to enable the verification device to recognize the relative position of the address information pattern 12b; the address information pattern 12b is used to represent a number. In this embodiment, the address synchronization pattern 12a is a black and white pattern segment of fixed length to provide a synchronization address of each portion of the address information pattern 12b. For example, the address synchronization pattern 12a may include black-white-black-white-black-white-black for a total of 7 pattern segments to define a synchronization address of each portion of the address information pattern 12b. The address information pattern 12b includes address information represented by 7-bit units. For example, if the address information is represented by 2 digits, black-black-white-black-white-black-white may represent 0010101 of 2-digit. For the first and seventh bits, the second to sixth digits can represent the address of the group of inspection patterns 10, for example, the second to sixth digits of 0010101, and the total five digits represent 10 digits of the ten digits. The rest of the way.

The shape, color, and format of the address pattern 12 are of course not limited to the above. The present invention can be applied to the present invention as long as it enables the computer to recognize the address information represented by the digitized pattern, such as a number. For the address pattern of the above example, reference is also made to the description of the Taiwan Patent Application No. 102100444 filed on January 7, 2013.

As for the digital pattern 12c, it is used to indicate a mark for human reading, and represents the same address information of the address pattern 12. Of course, the digital pattern 12c may also be optically read and recognized by a computer. Moreover, the main purpose of the digital pattern 12c is not for the print quality inspection device to read, whether it is used and the shape, color and format, which should not be the focus of the present invention. I will not repeat them here.

The printing quality inspection device of the present invention will be described below. Fig. 2 is a system diagram showing a printing quality inspection apparatus according to an embodiment of the present invention. As shown in the figure, the printing quality inspection device of the present invention comprises: a body 100 for carrying the main components of the printing quality inspection device, and a moving device 150 for moving the body 100 to scan the body in one direction. Print carrier 20 to be verified. The main component carried on the body 100 includes: a light source 110 for lifting Light for optical inspection; an optical detector 120 for detecting the synchronization pattern 11 printed on the print carrier 20, and outputting a synchronization signal; an image input device 130 for capturing the print carrier The inspection pattern 10 printed on the 20 and converts the captured image into a digital pattern; and an inspection device 140 for determining the printing on the printing carrier based on the content of the inspection pattern 10 captured by the image input device 130 quality.

In the present invention, the light source 110 can be any device that emits light. The light emitted by the light source 110, regardless of wavelength or spectral distribution, is not limited. However, since the main use of the present invention is the inspection of the printing quality, the light wave spectrum distribution of the light source 110 preferably includes most of the main wavelength bands in the visible light range, and white light is preferred. Of course, light containing other wavelengths or bands can also be used in the present invention, or in its particular application. As for the light-emitting mechanism of the light source 110, of course, there is no limitation. In terms of cost and application, fluorescent lamps and white LED lamps are preferred because of their ease of availability, low cost, and ease of use. However, other light-emitting elements can also be used in the present invention.

The optical detector 120 can use any commercially available optical detector as long as the synchronization pattern 11 printed on the print carrier 20 can be sensed. The optical detector 120 generally includes an objective lens, an optical path, and a detecting component. However, the structure is not limited to this. As long as the result of the sensing can be processed and output. The optical detector 120 is configured to sense the synchronization pattern 11 and emit a synchronization signal. For example, when the body 100 scans in the printing direction of the synchronous pattern 11 of the print carrier 20, when a synchronization pattern 11 is detected, a synchronization signal is issued. Based on the time at which the synchronization signal appears, the system can determine the speed of the scan at that time to correct the speed at which the image input device 130 reads the address pattern 12 and the color code pattern 13.

The image input device 130 can use any commercially available image input device, such as a digital camera, a camera, an image sensing wafer, etc., as long as the inspection pattern 10 printed on the print carrier 20 can be captured in a discontinuous or continuous manner. The address pattern 12 and the color code pattern 13 are mainly converted into a digital pattern. In the embodiment of the present invention, the image input device 130 still needs to include a editing function, that is, a plurality of captured digital images are edited into a single continuous image, or a plurality of images respectively include a set of color standard patterns 13 and a An image of the group address pattern 12. in Thus, the address pattern 12 provides information that is available for use because the address pattern 12 is typically printed simultaneously with the black mark 13a and represents the beginning of a set of color mark patterns 13. Of course, the basis for editing according to other pattern features is also impossible. In the prior art, a software product that performs the editing operation in an automated manner has become a common technique. People in this industry can easily develop the same technology or complete the editing job with commercially available editing software. The related art need not be described here. As for the pattern completed by the clip, or the pattern to be clipped, the enlargement or reduction correction can be performed according to the frequency or time point at which the sync signal appears. Such correction techniques are also within the scope of the prior art and need not be described here.

This inspection device 140 is also one of the focuses of the present invention. In the present invention, the function of the inspection apparatus 140 is to inspect the inspection pattern 10 printed on the print carrier 20 to determine whether the color of each of the monochrome color patches in the inspection pattern 10 is acceptable and whether the relative position is correct. The method for checking the color of the monochrome color code includes comparing the digitized information of each monochrome color code with a preset digital information value, calculating the difference, and determining whether the difference is less than or equal to one. Or a set of threshold steps. In other words, after the color of the monochromatic color patch pattern is digitized, it is generally possible to include grayscale values of three primary colors (optical primary colors or three primary colors on display) components (or alternatively black). The inspection device 140 can compare the composition of the gradation value with the gradation value of the preset specific three primary colors (or another black color), and calculate the difference value. Then, compared with one or a set of threshold values, when the difference value is less than or equal to the critical value, it is judged as pass. Of course, other methods of judgment are also applicable to the present invention.

As for the determination of the correctness of the position, the captured monochromatic color-coded shape coordinates can be thinned to obtain the edge line of the monochrome color-coded pattern. And an edge line perpendicular or substantially perpendicular to the scanning direction is used as the boundary of the monochrome color code. Thereafter, the pitch (difference value) of the edge lines of the adjacent two monochromatic color patches is calculated by comparing the front and rear edge lines of the respective monochrome color patches. The pitch is then compared to a predetermined threshold, and the pitch equal to or less than the threshold is qualified. In addition to being judged according to the edge line of each monochrome color mark, there are other feasible judgment modes that can be applied to the present invention.

In addition, the inspection device 140 also extracts from the inspection pattern 10 The address information represented by the address pattern 12 is combined with the inspection result of the set of inspection patterns 10. After the above judgment, the obtained result includes: address information of the set of inspection patterns 10, whether the color quality of each of the monochrome color patches is acceptable, and whether the position of each of the monochrome color patches is correct. As the mobile platform 150 continuously moves the body 100 through the print carrier 20, each set of inspection patterns 10 is scanned, captured, and inspected, and the print quality inspection device can output print quality inspection results for each unit of the printed matter.

In the print quality inspection device, the moving platform 150 is configured to move the body 100 in the arrangement direction of the inspection pattern 10 so that the image input device 130 continuously scans the print carrier 20. To achieve this, the mobile platform 150 may include one or two tracks and their corresponding rollers, a motor that drives the roller, and a mechanism that supports the body 100 and the optical detector 120. The mobile platform 150 can include switches, control buttons, etc. to initiate, stop, and control its operation. The architecture, components, and operation of such a mobile platform 150 are common in the prior art. The details are not mentioned here.

Under the above description, the printing quality inspection method of the present invention can be represented by the flowchart of FIG. 3, and includes the following steps: in step 301, the optical detector 120 detects the synchronization pattern 11 on the print carrier 20, and outputs a synchronization signal; in step 302, the image input device 130 continuously captures the inspection pattern 10 on the print carrier 20, and digitizes the inspection pattern 10; and in step 303, determines the location based on the digitization inspection pattern. The address information included in the image is obtained from step S304, and the color information contained in the color code is extracted from the digital verification pattern captured by the image input device 130. In this step, the color information may include color information of each of the monochrome colors; in step 305, it is determined whether the monochrome printing quality is in the qualified range according to the monochrome information contained in the color information; and the color information is determined according to the color information in step 306. The relative position of the monochrome area is included, and it is judged whether the monochrome printing position is in the qualified range; finally, in step 307, the inspection result is output, including the address information, the printing quality inspection result, and the printing position inspection result.

In the above steps, the quality judgment step of the print quality may be as described above, including comparing the monochrome information with a pre-stored monochrome information, judging the difference value, and judging the difference value within a threshold value. For the qualifying steps. At the time of judgment, the printing position is qualified The judging step may further include comparing a monochrome printing position with an adjacent monochrome printing position, calculating the difference, and determining that the difference is within a critical value. In addition, the determining step of the monochrome printing position may further include: capturing a monochrome printing area, determining an edge line of the monochrome printing area, and printing the edge line component along the direction in the edge line as the printing position. Next, among the edge lines, the edge line component in the opposite direction to the direction is used as the printing position. The method can include continuous inspections for continuous inspection. According to the judgment made by the above steps, the address information including the inspection patterns of each group, the color quality of each of the monochrome color patches, and the information of whether the positions of the respective monochrome color patches are correct can be obtained.

The present invention also encompasses print carriers that can be used to verify print quality using the above methods or apparatus. On the print carrier, the inspection pattern 10 as described above is printed to provide the print quality inspection apparatus of the present invention for inspection of the print quality using the print quality inspection method of the present invention.

The invention proposes a simple and accurate positioning means, so that the printing quality inspection device can perform accurate printing quality inspection with a simple mechanism. The printing quality inspection method and device proposed by the invention can be used to immediately provide an immediate quality inspection on the printing pattern of each unit after the printing carrier completes printing, and immediately output the inspection result. Users can eliminate poor quality printing units online to ensure print quality and increase productivity.

Claims (10)

A printing quality inspection device includes: a body for carrying: an optical detector for detecting a synchronization pattern on a printed carrier; and an image input device for capturing a verification pattern on the printed carrier, and Converting to a digital type; and an inspection device for determining a print quality on the print carrier based on the content of the inspection pattern captured by the image input device; and a moving platform for moving the body in a direction to enable The image input device scans the print carrier; wherein the inspection device corrects the inspection pattern according to the detection result of the synchronization pattern; and the inspection device determines the print pattern address on the print carrier according to the content of the inspection pattern; And wherein the synchronization pattern is used for synchronous control by the printing quality inspection device; and the inspection pattern includes an address pattern for indicating address information that can be recognized by the printing quality inspection device; and at least one set of color code Used to indicate the color information that can be recognized by the printing quality inspection device. The printing quality inspection device of claim 1, wherein the inspection pattern is a continuous inspection pattern string. The printing quality inspection device of claim 1, wherein the color information is a combination of primary color information or a combination of monochrome information. The printing quality inspection device of claim 3, wherein the monochrome information is a color that is printed each time when the color separation printing is performed. A printing quality inspection method includes the steps of: detecting an synchronization pattern on a print carrier by an optical detector, and outputting a synchronization signal; continuously capturing an inspection pattern on the print carrier by an image input device, and The inspection pattern is digitized, and the inspection pattern is corrected according to the detection result of the synchronization pattern; Determining the address information contained in the digital verification pattern according to the digital verification pattern; extracting the color information contained in the color code from the digital verification pattern captured by the image input device, including each of the monochrome information; The monochrome information contained in the information determines whether the monochrome printing quality is in the qualified range; determines whether the monochrome printing position is in the qualified range according to the relative position of the monochrome area contained in the color information; and outputs a test result, including The obtained address information, the printing quality inspection result and the printing position inspection result; wherein the synchronization pattern is used for synchronous control of the printing quality inspection device; and the inspection pattern includes a bit address pattern for indicating the printing The address information recognized by the quality inspection device; and at least one set of color code for indicating the color information that can be recognized by the print quality inspection device. The printing quality inspection method of claim 5, wherein the printing quality qualification determining step comprises comparing the monochrome information with a pre-stored monochrome information, determining the difference value, and comparing the difference value to a threshold value. Within the circumstances, it is judged to be a qualified process. The printing quality inspection method of claim 5, wherein the step of judging the printing position comprises comparing a monochrome printing position with an adjacent monochrome printing position, calculating a difference, and the difference is In the case of a devaluation, it is judged as qualified. The printing quality inspection method of claim 7, wherein the determining step of the monochrome printing position may include: capturing a monochrome printing area, and determining an edge line of the monochrome printing area, the edge line In the middle, the edge line component in one direction is treated as its printing position. The printing quality inspection method of claim 8, wherein the determining step of the monochrome printing position further comprises: processing the edge position of the edge line in the opposite direction of the direction as the printing position . For example, the printing quality inspection method of claim 5, and the continuous starting inspection operation for the continuous inspection.