JPH0345709B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The method of the present invention is useful, for example, when printing is performed on a board that has already been marked with reference to the mark during the production of a printed circuit board. Secondly, there is a plate matching method to ensure accurate printing.

Conventional technology For example, in the production of double-sided printed circuit boards that use through holes at predetermined positions as marks, the through holes are processed on the board and a circuit pattern is printed on it.In this case, the board is placed on the printing stage. A printing plate is fixed to the plate frame and positioned above it. In this state, it is necessary to make the circuit pattern on the printing plate and the through-holes on the board face each other in a predetermined relationship. However,
When fixing a printing plate to a plate frame, it is inevitable that some misalignment will occur. Plate matching is an operation that corrects these misalignments by adjusting the position of the printing plate or substrate.

The plate alignment described above is to align the through holes and the pattern on the printing plate, but it is also possible to use marks printed or processed on the board in advance, electronic component insertion holes, and In some cases, a hole or the like machined for alignment is used as a mark, and alignment is performed between the mark and the circuit pattern on the printing plate.

For example, Japanese Patent Application Laid-Open No. 57-133694, which repeatedly performs alignment and printing on one printing stage,
No. ``Alignment device for screen printing presses'' is known. This is the screen 11 as shown in Figure 2.
Printing pattern plate 12 made of photoresist film
The printed portion 17,1 of the printing plate 10 formed by
Pinholes 14, 14' are bored at predetermined positions in 7' (portion where no printing pattern is formed), and pinholes 14, 14' are formed at predetermined positions on the printing stage 31, which is disposed facing the printing plate 10, respectively. As shown in the figure, photoreceptors 15, 15' divided into four areas 151 to 154 are arranged, and light sources 18, 15' are sandwiched between the photoreceptors 15, 15' and pinholes 14, 14'.
8' are opposed to each other, and during plate alignment, the light passing through the pinholes 14, 14' is directed to the photoreceptors 15, 1.
This is done by determining which region of the printing plate 5' has been reached based on the change in output, and adjusting the position of the fixed plate frame 13 of the printing plate 10 or the printing stage accordingly.

However, the above operation is equivalent to plate alignment between the printing plate 10 and the printing stage 31.
Therefore, in order to align the printing plate 10 and the printing material 19 made of, for example, a substrate, the printing material 19 must be
must be positioned at a predetermined position with respect to the printing stage 31. Now, as a method of positioning the printing material 19 with respect to the printing stage 31, the guide holes bored in the printing material 19 and the stage 3
1, or by pressing the two outer sides of the printing material 19 against the guide cover provided on the stage 31, but the latter method has a drawback in accuracy, so the former method is mainly used. is used.

However, in the former case, it is difficult to automate the fitting between the pin and the guide hole, so a decrease in work efficiency is unavoidable.

Furthermore, even if the printing plate 10 and the printing stage 31, and the printing stage 31 and the printing material 19 are maintained in a predetermined positional relationship, slight deviations due to play in the printing plate 10 may occur during actual printing work. is unavoidable, and in the end, test printing is performed on the printing medium 19 and the photoreceptors 15, 1 on the printing stage 31 are printed.
It is necessary to finely adjust the position of the printing plate 5' or the position of the printing plate relative to the plate frame, and in this respect, a decrease in work efficiency is unavoidable.

In considering the above-mentioned problems, the first factor that reduces work efficiency is the positioning of the printing medium 19 with respect to the printing stage 31, which is repeatedly performed for each printing.

By the way, in FIG. 2, the printing medium 19 spans the entire width of the printing stage 31, and the photoreceptor 1 is placed at a predetermined position on the printing medium 19.
5, 15', positioning of the printing medium 19 with respect to the printing stage 31 becomes unnecessary.

In this way, the photoreceptors 15 and 1 are placed on the printing medium 19.
5' is difficult in practice, but it is equivalent to forming a mark such as a through hole or a pattern in advance at a position having a predetermined relationship with the portion of the printing pattern to be printed on the printing material 19. This can be achieved by adjusting the printing stage 31 or the plate frame 13 so that it coincides with the pinholes 14, 14'. However, in order to automate this process, it is necessary to automatically detect the opposing state of the mark and the pinhole, and adjust the printing stage 31 or plate frame 13 accordingly. However, it is difficult to detect alignment marks through small diameter pinholes. To solve this problem, as shown in FIG. 4, the printing plate 10 is provided with holes 3, 3' by enlarging the pinhole portion, and marks 2, 2' on the printing medium 19 are provided above the holes 3, 3'.
For example, image sensors 1 and 1' are arranged to detect the coordinates of the center of gravity of the mark, and are composed of a video camera and its image signal processing unit. It is conceivable to position the image sensors 1 and 1' so that a predetermined point, for example, the origin, coincides with the pinhole position of the printing plate 10. According to this, even if the printing medium 19 is not precisely positioned with respect to the printing stage 31, the positions of the marks 2 and 2' representing the predetermined positions are provided at predetermined positions on the printing plate 10. The plate frame 13 or the printing stage 31 is detected by the image sensors 1, 1', and the plate frame 13 or the printing stage 31 is moved depending on the detected value and the positioning target value, which is the deviation of the image sensor 1, 1' from the origin, for example.
The position of will be adjusted. That is, this is an operation of positioning a predetermined position of the printing material with respect to the image sensors 1, 1' which are in a predetermined positional relationship with the printing plate 10, that is, alignment is performed. This means that the plates have been aligned with the printing medium 19.

However, in this case, it is necessary to position the image sensors 1, 1' in place of the printing medium at a predetermined position on the printing plate, and as with the above, many trial printings are required before positioning. do.

The above is an example in which alignment and printing are performed on the printing stage, which is inefficient. On the other hand, for example, printing is performed continuously by aligning the printing medium and printing separately.
This is Japanese Patent Application Laid-Open No. 57-109655 "Printing Apparatus" proposed by the present applicant. As shown in FIG. 1, this apparatus includes an aligning machine 20 dedicated to positioning in series with a printing plate 10, a printing stage 31, an aligning stage 21, and an aligning machine 20.
A passage for a conveyance stage 41 is formed in the middle, a rail 42 is provided in the passage, and the conveyance stage 42 is engaged with the rail 42. In addition, the length of the transport stage 41 is approximately the same as the distance between the alignment and printing stages 21 and 31, and the rail 42 is as shown in FIG.
It has a three-step height change function of ~c, thereby aligning the top surface of the conveying stage 41, and making it horizontal, protruding, and recessed with respect to the top surface of each printing stage 21, 31. FIG. 6 shows an example of the matching machine 20. This allows the second pedestal 54 to be rotatably engaged with the shaft 52 protruding from the first pedestal 51, and is directed by the spherical seats 53, 53, so that the rightward extending portion 55 of the pedestal 54 53
The rightward extending portion 55 of the pedestal 54 is supported by
The pulse motor 5 fixed on the first pedestal 51
6 through a flexible joint and a ball screw mechanism, a groove is formed in the second pedestal 54 in a direction perpendicular to the plane of the paper, and a groove is provided in the lower part of the third pedestal 58. A groove member 57 is slidably fitted, and the front end of the groove member 57 is connected to the rotating shaft of a pulse motor 59 fixed to the second pedestal 54 via a ball screw mechanism, and the front end of the groove member 57 is connected to the third pedestal 58.
A groove is formed on the top in the left and right direction, into which a groove member 60 provided at the bottom of the alignment stage 21 is slidably fitted, and the right end of the groove member 60 is fixed to the third pedestal 58. The first and second image sensors 61 and 62 are arranged to face the alignment stage 21, and are coupled to the rotating shaft of a pulse motor 63 via a ball screw. Furthermore, first,
The arrangement positions of the second image sensors 61 and 62 are as follows:
Image sensors 1 and 1' explained in FIG. 4 above
The position is shifted to the left by the stroke of the transport stage 41.

The printing process using this device will be described below. First, the printing material 19 is fed onto the alignment stage 21, and rough positioning is performed by pressing its two orthogonal sides against the guide plate 22 and guide pin 23 (having protruding and recessing functions) using pressurers 25 and 26. After that, the printing medium 19 is attracted onto the alignment stage 21. Note that the pins 23, 23 are depressed at this time. Next, the positions of the images of the marks 2 and 2' on the printing medium 19 are detected by the first and second image sensors 61 and 62, and the detected positions and the positions where they should exist, that is, the alignment target positions, are determined. The rotation amount of the pulse motors 51, 59, 63 is controlled according to the deviation of the alignment stage 21,
Alignment is performed in two directions: a direction perpendicular to the page and a left-right direction. Subsequently, the conveyance stage 41 is brought into the horizontal state as shown in FIG.
1 in the protruding state shown in FIG. 5b, and the transport stage 41
to the right by a predetermined stroke. As a result, the aligned printing medium 19 reaches above the printing stage 31, and after being attracted to the printing stage 31 in this state, the attraction of the transport stage 41 is released. Then, the printing machine 30 is caused to perform printing. At the same time, the conveyance stage 41 is brought into the depressed state as shown in FIG. Then, when alignment and printing are completed, the aligned printing material is moved onto the printing stage 31 in the same manner as described above, and the printed printing material is moved to the position of the unillustrated unloading machine on the right side of the printing press 30. and the above procedure is repeated.

Although the alignment and printing work efficiency is improved as described above, the prior alignment of the image sensors 61 and 62 with respect to the printing plate 10 still requires a complicated operation. That is, this operation performs a test print, measures the deviation between the predetermined alignment mark and the distance between the printed pattern, adjusts the position of the image sensor by the amount of deviation, and then performs a test print again to finally eliminate the deviation. This method has the problem of requiring a large amount of time.

Problems to be Solved by the Invention Incidentally, Japanese Patent Application Laid-Open No. 1117-1987, ``Apparatus for implementing a method for adjusting the position of a stencil with respect to a printing or textile printing table,'' discloses that The amount of movement is determined by placing the material, feeding it to a printing position, printing a pattern on the transparent material there, and then moving the transparent material with the printed pattern so that the printed pattern overlaps the reference pattern below it. A method is disclosed in which the deviation between both patterns is determined from the above, and then the stainless steel is adjusted by the amount of the deviation. This method adjusts the position of the image sensor by the amount of deviation in the method described above, whereas the stencil is adjusted by the amount of deviation, and has the same problem as the above method that it takes a lot of time.

The present invention aims to solve the problem that alignment of a printing plate and an image sensor is complicated and takes a lot of time.

Method for Solving the Problem Now, in order to solve the above problem, the printing plate facing the alignment mark should be Let's form a new dummy mark printing section on the top and consider its positional relationship.

Note that the formation position of the dummy mark printing area on the printing plate does not need to be determined by facing the printing material and the printing plate, but by determining the positional relationship between the pattern to be printed on the printing material and the matching mark on the printing plate. It is only necessary to replace the positional relationship between the pattern printing section and the dummy mark printing section. Then, the printing material is positioned on the alignment stage, and after alignment is performed to align the alignment mark with a predetermined temporary alignment target position, it is moved by a predetermined stroke by the conveyance stage and positioned on the printing stage. Try printing the dummy mark mentioned above. In this way, if the printing plate and the printed book position are in a predetermined state, the dummy mark will be overprinted on the alignment mark, but if they are not in the predetermined relationship, the two marks will be misaligned.

Now, in order to examine this deviation again on the alignment stage, the printed material is moved by a predetermined stroke in the opposite direction by the conveyance stage and positioned on the alignment stage. Then, the position of the alignment mark naturally indicates the provisional alignment target position in the alignment described above, but the position of the dummy mark is the position of the alignment mark in order to make the printing plate and the printing medium face each other in a predetermined positional relationship. The position to be aligned, that is, the true alignment target position is shown as is. However, adjusting the position of the image sensor so that the dummy mark and alignment mark match requires a large amount of time as described above. Now, if we change our perspective and consider the position of this dummy mark within the image sensor, this position is originally the target position for alignment. given that,
If this position itself is newly set as the alignment target position, no mechanical adjustment will be necessary; just by aligning it, the printing plate and printing material will always be kept in the specified positional relationship. It will be dripping.

The present invention has been made based on the above study results, and includes alignment marks at two predetermined locations on an alignment stage of an alignment machine that has a movement control function in two orthogonal directions on a plane and in a rotational direction. The position of the alignment mark is detected by first and second image sensors arranged at predetermined positions facing the alignment stage on which the printing material is fixed, and the position of the alignment mark is detected according to the deviation between the detected position and the alignment target position. Alignment is performed by controlling the amount of movement of the alignment stage in each direction, and then the aligned printing material is transferred from the alignment stage to the conveyance stage of the conveyance machine, and the predetermined stroke of the conveyance stage is moved. Alignment in a printing method in which the aligned printing material is transferred onto the printing stage of a printing press by movement, then fixed on the printing stage and printed with a printing plate, is a plate alignment method performed in advance prior to printing. The printing plate is provided with a dummy mark printed portion at a location facing the alignment mark,
Printing is performed by fixing a test printing material without an alignment mark on the printing stage, and then fixing the printed test printing material to the transport stage and returning it to the alignment stage. The dummy mark image positions in the first and second image sensors are set as alignment target positions for alignment with respect to the printing medium, whereby plate alignment can be performed with only one trial printing. The present invention provides a method. That is, in the present invention, when making a printing plate, a printed portion of a dummy mark is formed on the printing plate that faces the alignment mark of the printing medium in a state where plate alignment is completed. Therefore, in forming a printing plate, it is easy to accurately form the printing portion of the dummy marks in such a predetermined relationship, and
The dummy mark is simply overprinted on the alignment mark during printing, and does not cause any trouble to the printing process or the printing material. When aligning the plates, first, a test print with approximately the same dimensions as the printing material and without alignment marks attached, or a test print to cover the alignment mark on the printing material. A test printed body with a membrane etc. attached is fixed on a printing stage and printing is performed. As a result, a dummy mark is printed on the test print along with predetermined printing. Subsequently, this test printed body is transferred from the printing stage to the conveying stage, and is moved to the aligning machine side by a predetermined stroke. As a result, the test print is positioned on the alignment stage, and the position of the dummy mark printed on the test print in this state is equal to the stroke of the dummy mark printing part of the printing plate and the transport stage. It will be in a remote location. Next, in this state, the position of the dummy mark is detected by the first and second image sensors,
The position is set as the matching target value in the matching machine. The above is the version matching.

Hereinafter, the above-mentioned alignment is performed by detecting the alignment mark of the printing material supplied on the alignment stage using the first and second image sensors, and detecting the alignment mark according to the deviation between the alignment mark and the alignment target position set in the plate alignment. This is done by controlling the amount of movement of the alignment stage in each direction, and after alignment is completed, the printing material is moved by a predetermined stroke and positioned on the printing stage, and then printing with a printing plate is performed. .

Note that the method for detecting the positions of the dummy marks and matching marks using the image sensor is not described in detail here, but after the shading of the image of each mark is binarized, its center of gravity is calculated, and it is calculated from the coordinates of the image sensor. Methods for representing by system are known (for example, Nikkei Mechanical 1984.7.30 205/213), and appropriate image processing methods can be used.

It also does not provide details on how to control the alignment machine according to the deviation between the mark detection position and the alignment target position, but these deviations can be calculated geometrically, and the This is done by controlling the amount of pulses supplied to the stepping motors 59, 56, and 63 of the alignment machine 20 (see FIG. 6) in accordance with the deviation.

Example: The first and second image sensors have a resolution of 10 μm, and the alignment mark is 500× which is the printing material.
In the case of a 1/8 inch hole drilled on a 600 mm circuit board, according to the present invention, printing with positioning accuracy within ±10 μm (detection resolution) can be achieved with only one trial printing. There is.

Effects of the Invention As described above, the present invention provides a printed portion of a dummy mark on a printing plate that faces an alignment mark during printing, and when aligning the plates, prints the dummy mark on a test print. After printing, the test print is placed on an alignment stage a predetermined stroke away, the position of the dummy mark is detected, and the position is set as the alignment target coordinate, and plate alignment is automatically performed. This allows plate matching to be performed easily and in a short time.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of an apparatus for carrying out the present invention, Fig. 2 is a front view showing an apparatus for carrying out a conventional plate matching method, and Fig. 3 is a photoreceptor similar to that shown in Fig. 2. 4 is a front view showing a device for carrying out the plate matching method devised in the process leading to the present invention, and FIG. FIG. 6 is a side view showing the height change state of the stages, and FIG. 6 is a front view of the aligning machine of FIG. 1. 21: Alignment stage, 31: Printing stage, 4
1: Transport stage, 61, 62: Image sensor.

Claims (1)

[Claims] 1. A printing medium having alignment marks at two predetermined locations is fixed on an alignment stage of an alignment machine that has a movement control function in two orthogonal directions on a plane and in a rotational direction, and is placed at a predetermined position facing the alignment marks. Alignment is performed by detecting the position of the alignment mark by first and second image sensors arranged at the position, and controlling the amount of movement of the alignment stage in each direction according to the deviation between the detected position and the alignment target position. Then, the aligned printing medium is transferred from the alignment stage to the conveying stage of the conveying machine, and the aligned printing medium is transferred onto the printing stage of the printing machine by moving the conveying stage by a predetermined stroke. In a printing method in which the printing plate is fixed on a printing stage and then printed, the printing plate is aligned, conveyed, and printed in advance. A dummy mark printing section is provided at a location facing the mark, a test printing material without an alignment mark is fixed on the printing stage and printing is performed, and then the printed test printing material is The dummy mark image position within the first and second image sensors at that time is set as an alignment target position for alignment with respect to the printing medium. The method of matching the plates.