JPH0758395B2 - Transfer film distortion correction method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention accurately applies a basic design on a block to a three-dimensional curved surface when printing a pattern, a character or the like on a molded article having a three-dimensional curved surface. The present invention relates to a transfer film distortion correction method and device for reproducing.

[Conventional technology]

In recent years, in-mold molding in which a printing film is put in a mold at the same time as injection molding and only ink is transferred, so-called thermoject, has become widespread.

FIG. 8 is a diagram showing a basic configuration of such a thermogenct. In the figure, 1 is a supply roll, 2 is a transfer film, 3 is a cylinder, 4 is a heater, 5 is a mold (male), 6
Is a mold (female), and 7 is a winding roll.

In the case of a three-dimensional molded product after being aligned with a mold, the transfer film 2 on which a pattern or a character to be printed is printed is heated by a heater 4 so as to be easily stretched, and a male mold 5 or The pressure is applied to the female die 6 to transfer the ink to the injection-molded article for transfer.

In this way, printing is performed on the molded product 8 as shown in FIG. 9 to obtain a printed molded product 9. However, since the transfer film is stretched at the time of molding, the strain as shown in FIG. 10 actually occurs. I will end up.

Therefore, conventionally, an original plate is prepared by making a plate having the first basic design as it is, and then a printing plate is made to make a printing plate (for example, a silk screen) and printed on a transfer film. This transfer film is molded and transferred (trial hitting), the amount of strain is measured manually, and the master block is corrected. Then, a process of making a plate, a printing plate, and a trial printing for printing on the basis of the corrected original plate again and carrying out a manual correction in the same manner as described above was repeated several times to obtain an original plate to be finally used.

[Problems to be solved by the invention]

However, the conventional manual distortion correction requires much labor and time, resulting in an extremely high cost, and it is very difficult to produce a good master block.

The present invention is intended to solve the above problems, and an object thereof is to provide a transfer film distortion correction method and apparatus capable of correcting distortion due to transfer to a molded product or the like in a short time and with high quality. To do.

[Means for solving problems]

To this end, the present invention forms and transfers a transfer film having a pattern for strain measurement, from the difference between the position coordinates before and after forming and transferring a plurality of reference points on the pattern for strain measurement. Distortion of the transfer film during molding and transfer is detected for each reference point, and based on the detected distortion, each point on the block image is converted to a point with the coordinates at that point minus the distortion at that point. By doing so, the transfer film distortion correction method characterized by preliminarily correcting the block copy of the transfer film so as to cancel the distortion of the block copy due to molding and transfer, and a block copy data input means having a basic design, A transfer film having a pattern for measurement, and a pattern reading means obtained by molding / transferring the transfer film,
From the image processing unit to which the read pattern is input, the image processing data obtained from the distortion measurement pattern, and the image processing data obtained from the transferred and molded distortion measurement pattern, Distortion correction data is created by subtracting the coordinates before molding / transfer from the coordinates after molding / transfer for the points to obtain the distortion during transfer film molding / transfer, and based on the created distortion correction data An arithmetic processing unit that corrects the block copy data by converting the point into a point having coordinates obtained by subtracting the distortion correction data at the point from the point, and a block copy is produced based on the corrected block copy data. It is characterized by a transfer film distortion correction device including an output device.

[Action]

The present invention, the distortion of the transfer film at the time of printing from the misregistration of the intersection point at the time of molding and transfer of the transfer film on which the grid pattern or the oblique light coordinates corresponding to it, or the distortion measurement pattern in polar coordinates is printed. It is possible to obtain a pattern, characters, or the like without distortion at the time of molding / transferring by detecting and producing a master block that is corrected in advance based on the detected distortion.

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a diagram for explaining a processing flow, and FIGS. 3 to 6 are diagrams showing a distortion correction method. 11 is an image reading device, 12 is a block data input device, 13 is a data processing control unit, 14 is an image processing unit, 15 is an arithmetic processing unit, 16 is a block data file, 17
Is a distortion amount interpolation data file, and 18 is a plotter.

In the figure, the image reading device 11 reads, for example, a molded / transferred image when a strain measurement pattern grid pattern is transferred to a molded product or the like, and the read image data is used as the image processing unit 1.
Is input to. The image processing unit 14 performs image processing such as binarization processing and thinning processing to detect an intersection of straight line groups of orthogonal grid patterns. The data of the intersection thus detected is input to the arithmetic processing unit 15. Further, a pattern for distortion measurement, such as a grid pattern, before molding / transferring on a plate or a transfer film is input to the arithmetic processing unit 15 as reference data from the same image reading device 11. In the calculation processing unit 15, the intersection of the grid pattern of the molded / transferred image and the intersection of the grid pattern from the block data are compared and calculated, and the distortion amount (direction and size) at each intersection is calculated.
And, if necessary, by interpolating the distortion amount between each intersection. In this case, the reference data may be input from the input device 11 each time, or may be stored as the reference data file 16 and read out. Further, the interpolation of the distortion amount between each intersection may be calculated from the distortion amount at each intersection, or the interpolation data for the distortion at each intersection may be stored as a table file 17 and read out.

When the amount of distortion due to molding and transfer is obtained in this way, this distortion amount is subtracted from the basic design block data to correct the distortion,
The plotter 18 is driven by the corrected output, and as a result, the distortion-corrected block copy is produced.

Next, the distortion correction according to the present invention will be described in detail with reference to FIGS.

First, an ITV or other camera captures a grid pattern (a strain measurement pattern) and the molded and transferred grid pattern (a strain measurement pattern), and an image is input (step). At this time the third
The grid pattern as shown in (a) and (c) is the same as (b) in the figure.
Distortion occurs as shown in (d). Then, the amount of strain at each point is detected by detecting how much each intersection of this grid pattern deviates from the original position and in what direction, specifically, the x-axis direction and the y-axis direction. Measure each component of (step).

FIG. 4 shows in detail how the distortion amount is measured and corrected.

FIG. 4A shows a distortion measurement pattern, which uses a grid of Cartesian coordinates and is read as reference image data by an image input device using an ITV or CCD camera.

Further, the distortion measuring pattern is formed and transferred, and the distortion is read again by the same image input device. This read distortion image and an example are shown in FIG.

In order to measure the amount of distortion, first, the corresponding (identical) ones are determined at each seat point of the reference image and the distortion image. For example, the point (x, y) = (0,0) in the reference image and the point (x ′, y ′) = (0,0 in the distorted image
If the points 0) are specified to be the same, the correspondence is determined for the other coordinate points, and if the difference Δx = x′−x Δy = y′−y of the coordinates at these corresponding points is calculated, the amount of distortion is calculated. Is required.

Fig. 4 (c) (d) shows how the measured strains Δx and Δy are.
Shown in. Since Δx and Δy are quantities that are determined corresponding to the points (x, y), Δx (x, y) and Δy (x, y) are measured only at the intersections of the respective coordinates. , The amount of distortion at any position (x, y) between each intersection must be approximately calculated by interpolation based on the value at each intersection. Such interpolation is performed on a curved surface, but as a method, bilinear surface, Coons
(Koons) surface Bicubic surface, Bezier surface, B
Various spline curved surfaces are known.

In this way, when the intersections and the distortion amount between the intersections are obtained, the distortion amount is subtracted and corrected from the composition data (vector data) having the basic design to create the artwork. This correction method is the fourth
Shown in Figure (e) and (f).

FIG. 4 (e) is a graph in which the amount of distortion is added to the coordinate value, that is, x + Δx (x, y) is three-dimensionally plotted on the (x, y) coordinate. This three-dimensional graph shows the correspondence between the point (x, y) on the reference image and the x'component of the corresponding point (x ', y') on the distorted image after molding / transferring. That is, the curved surface in the figure shows the relationship of x ′ = x + Δx (x, y).

Similarly, FIG. 4F shows the correspondence between the point (x, y) on the reference image and the y'component of the corresponding point (x ', y') on the distorted image after molding / transferring. There is. That is, the curved surface in the figure shows the relationship of y ′ = y + Δy (x, y).

Using these figures (e) and (f), the point (x ', y') on the distorted image is the point (x,
y) is required.

For example, consider a point (u ', v') on a distorted image.

From the graph in Fig. 4 (e), the set of points on the (x, y) plane (reference image) satisfying the condition of x '= u' is obtained through the distortion amount curved surface and the curve as shown in the figure is obtained. I know that it will be A.

A set of points on the (x, y) plane (reference image) satisfying the condition of y '= v' is a curve B. Next, the point (u, v) on the (x, y) plane (reference image) corresponding to the point (x ′, y ′) = (u ′, v ′) on the distorted image is x ′ = u ′ Since it is a point that simultaneously satisfies the two conditions of y '= v', there are two curves
You can see that it is the intersection of AB.

In this way, the point (u ′, v ′) on the distorted image corresponds to which point (u, v) on the reference image (block copy), so any figure ( It is possible to find the (corrected) block-print figure corresponding to the design. In this way, a corrected master block as shown in FIGS. 5 (a) and 5 (c) is produced (step).

Although the distortion in the two-dimensional plane is shown in FIGS. 3 to 5, it can be applied to a three-dimensional curved surface, and in that case, as shown in FIG. ₁ ,
For S _2, when viewed from an arrow A direction orthogonal to calculate the positional deviation of each intersection, if to calculate the positional deviation when viewed from the arrow B direction orthogonal thereto with respect to the plane S ₃ Good.

FIGS. 6B and 6C show another distortion correction method. In this figure, for example, (x ', y') representing a distorted image
The straight line K ', l' on the plane represents the reference image (block copy) (x,
y) To correspond to the plane, the intersection with the grid representing the coordinates is used. Since the correspondence between each line segment of the grid that has been distorted on the (x ', y') plane and the line segment of the original grid is clear, the intersection with the straight line K ', l' is (x, y). It suffices to decide which position of the corresponding line segment on the plane corresponds to.

For example, in the figure, the intersection C ′ divides the line segment of the grid into m: n, but if the intersection C is also divided into m: n on the (x, y) plane, the position of the point C is determined. In this way (x ',
If the points abc ... f on (x, y) corresponding to a'b'c '... f' on y ') are found and connected by broken lines, the broken line Kl corresponding to K', l 'can be found. . In this case, the polygonal line is obtained, but if the grid is made thin enough, the precision of the polygonal line will be improved and it will be close to the curve to be obtained.

As another method of such a correction method, the figures on the (x ', y') plane (distorted image) are associated with each other by mapping transformation of the square grids by mapping transformation. You may associate it with the top).

FIG. 7 is a schematic diagram of a system for performing transfer film distortion correction according to the present invention.

In the figure, a camera 22 prints on a molded product 21 or the like, a so-called 2.5-dimensional grid pattern with some unevenness is photographed, written in a frame memory 23, and distortion correction processing is performed by a CPu 24. In the case of the three-dimensional object 25 in which the depth of field is a problem, a parallel beam such as a laser beam is used for image capturing and data input. The CPu24 exchanges data with the plate-making data preparation system 26 consisting of the block-drawing drawing CAD system 27 and the plate-drawing machine 28, detects the distortion amount, creates the data with the distortion amount corrected, and creates the plotter 29. Drive and get the corrected artwork 30.

In the above embodiment, the grid pattern based on the orthogonal linear coordinates is used as an example of the distortion measurement pattern, but a reference pattern based on oblique light coordinates or polar coordinates may be created to perform similar distortion correction.

〔The invention's effect〕

As described above, according to the present invention, the distortion amount due to printing is calculated with a reference pattern such as a grid pattern, and the distortion correction is performed based on this distortion amount, so that the distortion correction can be performed accurately in a short time. Then, it becomes possible to perform high-quality printing by applying it to a molded product or the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a diagram for explaining a flow of processing, FIG. 3 is a diagram showing distortion of a grid pattern due to transfer, and FIG. 4 is an amount of distortion. FIG. 5 is a diagram for explaining an interpolation method, FIG. 5 is a diagram showing correction of a grid pattern, FIG. 6 is a diagram for explaining a distortion correction method, and FIG. 7 is for carrying out transfer film distortion correction according to the present invention. Schematic diagram of the system of No. 8
FIG. 9 is a diagram showing the basic structure of the thermoject, FIG. 9 is a diagram showing a printing process by the thermoject, and FIG. 10 is a diagram showing a printing result. 11 …… Image reading device, 12 …… Work block data input device, 13
...... Data processing control unit, 14 ...... Image processing unit, 15 …… Computation processing unit, 16 …… Work block data file, 17 …… Distortion amount interpolation data file, 18 …… Plotter.

Claims (4)

[Claims] 1. A transfer film having a strain measuring pattern is formed / transferred, and is formed from the difference in position coordinates before and after forming / transferring a plurality of reference points on the strain measuring pattern.・ Detects the distortion of the transfer film at the time of transfer at each reference point, and converts each point on the block image to a point with the coordinates obtained by subtracting the distortion at that point based on the detected distortion. Thus, the transfer film distortion correction method is characterized in that the master copy of the transfer film is corrected in advance so as to cancel the distortion of the master copy due to molding and transfer. 2. The transfer film distortion correction according to claim 1, wherein the distortion measuring pattern is composed of a group of straight lines connecting unit scales in orthogonal linear coordinates, oblique coordinates, or polar coordinates, or a group of straight lines and curves. Method. 3. The transfer film distortion correction method according to claim 1, wherein the reference point is formed by the straight line groups or the intersection of the straight line groups and the curved line groups. 4. A master copy data input means having a basic design, a transfer film having a strain measuring pattern, a reading means for a pattern obtained by molding / transferring the transfer film, and the read pattern are inputted. An image processing unit, image processing data obtained from the distortion measurement pattern,
And from the image processing data obtained from the transferred and molded strain measurement pattern, subtracting the coordinates before molding and transfer from the coordinates after molding and transfer for each point of the block image during transfer film molding and transfer Distortion correction data is created by calculating the distortion of each of the points, and each point on the block image is converted to a point with coordinates obtained by subtracting the distortion correction data at that point based on the created distortion correction data. A transfer film distortion correction device including an arithmetic processing unit that corrects the block copy data according to the above, and an output device that produces a block copy based on the corrected block copy data.