JP2734527B2 - Screen printing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printer for printing cream solder, thick film circuit paste, etc. on a printed circuit board with high accuracy.

2. Description of the Related Art In recent years, a screen printing machine has been applied to mass production such as printing cream solder on a printed circuit board on which electronic components are mounted, and a fully automatic screen printing machine has begun to spread. Under such circumstances, various methods of holding the printing material with high reliability have been studied.

Hereinafter, the above-described conventional screen printing machine will be described with reference to the drawings.

As shown in Fig. 3, the conventional screen printing machine
There is an apparatus described in Japanese Patent Publication No. 60-7399. In the figure, reference numeral 1 denotes a printing material, 2 denotes a stage on which the printing material 1 is placed and fixed, 3 denotes a plate, 4 denotes a transport link for transporting the printing material 1, 5 denotes a cylinder that moves the stage 2 up and down, and 6 denotes a lift of the stage 2. Is a protection plate pushed up by the push rod 7. The printing material 1 conveyed by the conveyance link 4 moves up the stage 2 by the cylinder 5 and at the same time pushes the protection plate 6 up by the push rod 7 so that the upper surface of the printing material 1 and the upper surface of the protection plate 6 are burdened. Screen printed.

In FIG. 3, as a method of fixing the printing material 1 placed on the stage 2, there is a method of sucking and fixing the printing material using a negative pressure suction action as disclosed in Japanese Patent Laid-Open No. 160252/1986. .

However, with the above-described configuration, when printing is performed on the printing object 1a having the warpage shown in FIGS. 4 and 5, the portion having the warpage is printed without being suction-fixed to the stage 2. Before the start of printing, the lower surface of the screen 3 is coated to adjust the viscosity of the paste printed on the printing material 1 and to minimize printing blemishes and blurring that occur when a fine print pattern is formed. Since a gap is provided or brought into contact between the printed materials 1, in the case shown in FIG. 4 or the like, the gap Ca in the center portion is different from the gap Cb in the sled portion.
Print pattern and the print pattern of the print substrate 1a are displaced, and the print amount becomes uneven. In the worst case, bleeding and blurring occur. In the case of FIG. 5, the sled portion of the printing material 1a pushes up the screen 3. In such a case, for example, the printing material 1a rotates in the direction of arrow D or moves in the direction of arrow E. However, before printing, there is a problem that the pattern of the screen 3 and the pattern of the printing medium 1 are deviated.

Therefore, as another method, there is a screen printing machine as shown in FIG. Reference numeral 8 denotes a printing material, 9 denotes a conveyance rail for conveying the printing material 8, and 10 denotes a collar for protecting the screen 11 during printing.
A protection plate 12 having a vertical movement is provided, 13 is a holding pin for holding the printing material 8, and 14 is a vertically movable table. Printed material 8
Is transported by the transport rail 9, at which time the collar 12 of the protective plate 10 moves upward and escapes so as not to contact the upper surface of the printing substrate 8. After positioning the printing material 8 at a predetermined position by a positioning device (not shown), the protection plate 10 is lowered, and the printing material 8 is pressed down by the collar 12 to fix the printing material 8, and thereafter, the table is fixed. 14 is printed at a position where the upper surface of the protection plate 10 is raised to near the lower surface of the screen 11.

Problems to be Solved by the Invention However, in the above-described configuration, as shown in FIGS. 7 and 8, the end of the printing material 8 is pressed by the width F, and the upper surface of the protection plate 10 and the printing material are fixed. Since there is a difference in height G on the upper surface of the print 8, there is a problem that printing cannot be performed only in the width of H from the edge of the printing object 8. The area where printing cannot be performed is shown by the shaded portion J in FIG.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a screen printer capable of printing cream solder, thick film circuit paste, and the like on a printed circuit board or the like with high accuracy.

Means for Solving the Problems To solve the above problems, the screen printing machine of the present invention protects the screen plate at the time of printing, and a pair of protection plates provided to face each other to support the printing material, Provided between the protective plates, a holding plate for holding the printing material, and a holding plate provided on the upper surface, which is always located below the printing material, and when positioning the printing material, the printing material is placed on the holding plate, and A table that can be raised and lowered until the upper surface is substantially the same height as the upper surface of the protection plate, and a plurality of fixed units having a squash that can be brought into contact with the edge of the substrate and can be biased to the upper surface of the substrate. A roller and a plurality of movable rollers which are located substantially opposite to the fixed roller and have a flange which can be urged against and contact with the upper surface of the printing material, and which are urged against the edge of the printing material. Provided, with fixed roller brim and movable roller brim, The printing apparatus is provided with a configuration in which the printing medium is pressed from above and fixed.

Function The present invention can reliably fix a print having a warp to the holding plate by the above-described configuration, so that the print does not deviate from the screen pattern, and the gap between the lower surface of the screen and the upper surface of the print is made uniform. The printing amount of the paste can be made uniform anywhere on the printing material, and printing bleeding and blurring can be suppressed to a minimum, and the printing material having a sled does not shift from a predetermined position where the printing material is fixed. Therefore, it is possible to minimize the area of the printing object that cannot be printed when the printing material is pressed from above.

Hereinafter, a screen printer according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view of a main part of a screen printing machine according to an embodiment of the present invention, and FIG. 2 is a schematic plan view taken along the line KK in FIG.

1 and 2, reference numeral 15 denotes a positioning table for positioning the print substrate 16. Reference numerals 17a and 17b denote a pair of protective plates for protecting the screen 18 during printing and supporting the edges of the printing material 16 conveyed from the L direction, 19 are holding plates for holding the printing material 16, 20 With the holding plate 19 placed on the upper side, the cylinder 21 is normally positioned at the lower portion of the printing material 16 by driving the cylinder 21.When positioning the printing material 16, the printing material 16 is placed on the holding plate 19, and the upper surface of the printing material 16 is Is a table which moves up and down until it is almost the same height as the upper surfaces of the protection plates 17a and 17b. A guide post 22 supports the table 20, and is slidably fitted to a bush 24 fixed to a base 23. . Reference numeral 25 denotes a front fixed roller capable of abutting on the front edge of the printing material 16, which has a collar 26a at an upper portion, and moves up and down by driving a cylinder 27a. Normally, it is moved upward by driving the cylinder 27a. Reference numeral 28 denotes a rear movable roller which is substantially opposed to the front fixed roller 25 and which can be brought into contact with the rear end edge of the substrate 16 by moving the cylinder 28a back and forth.
b and moves up and down by driving the cylinder 27b. The rear fixed roller 28 always moves upward by driving a cylinder 27b that moves up and down, and moves rearward by driving a cylinder 29a. 30 is a cylinder that moves left and right 29
By the driving of b, the left fixing roller abuts on the left edge of the printing material 16 and has a collar 26c at the upper portion, and moves up and down by the driving of a cylinder (not shown). Always a cylinder
The cylinder 29b is moved to the left by the drive of 29b, and is moved below the lower surface of the print substrate 16 by the drive of a vertically moving cylinder (not shown). Reference numeral 31 denotes a right movable roller which urges and abuts on the right edge of the print substrate 16 by driving a cylinder 29c which moves left and right, has a collar 26d at an upper part, and is driven up and down by driving a cylinder (not shown) which moves up and down. The moving right movable roller 31 is provided at a position substantially opposite to the left movable roller 30. The positioning table 15 is moved up and down by a driving source such as a cylinder (not shown) until the upper surface of the printing substrate 16 comes near the lower surface of the screen plate 18 after positioning the printing substrate 16. The holding plates 17a, 17b are fixed to the columns 32.

The operation of the screen printing machine configured as described above will be described below with reference to FIGS. 1 and 2.

In FIG. 1, the left fixed roller 30 is raised and urged toward the right movable roller 31 side. In this state, the printing medium 16 is fed in the direction of the arrow L (the drive source is not shown), and is brought into contact with the left fixed roller 30 to stop. Thereafter, the print substrate 16 is placed on the holding plate 19, and is raised until the upper surface of the print substrate is substantially flush with the upper surfaces of the protection plates 17a and 17b. After that, the rear fixed roller 28 is
25, the front and rear edges of the printing material 16 are sandwiched between the front fixed roller 25 and the rear movable roller 28, and at the same time, the right fixed roller 31 is raised and urged to the left movable roller 30 side. The left and right edges of the print 16 are held between the left fixed roller 30 and the right movable roller 31 to position the print 16. After positioning, the front fixed roller 25, the rear fixed roller 28, the left fixed roller 30, and the right movable roller
31 is lowered from above the print substrate 16 so that each of the collars 26a to 26d
Then, the printing material 16 is pressed down, and at the same time, the printing material 16 is suction-fixed to the holding plate 19 by using a negative pressure suction action (not shown).

Next, the printing substrate 16 is raised to near the lower surface of the screen plate 18 and the printing process is started. After printing, it operates in the reverse order to send the printing substrate 16 to the next step (the drive source is not shown).

As described above, according to the present embodiment, the positioning plate 15 protects the screen plate 18 at the time of printing, and a pair of protection plates 17a and 17b provided opposite to each other so as to support the printing material 16; The holding plate 19 for holding, the holding plate 19 is provided on the upper side, and is always located below the printing material 16, and at the time of positioning, the printing material 16 is placed on the holding plate 19, and the upper surface of the printing material 16 is It has a table 20 that can be raised and lowered until it is almost the same height as the upper surfaces of the substrates 17a and 17b, and a collar 26a that can abut on the front edge of the substrate 16 and that can urge and contact the upper surface of the substrate 16 The front fixed roller 25 and the front fixed roller 25 are substantially opposed to each other, and are urged against the upper surface of the print substrate 16 and can be brought into contact with the collar 26b.
Having a rear fixed roller 28 that can be urged against and abutted against the rear edge of the printing material 16, and can be abutted on the left edge of the printing material 16,
A left-side fixed roller 30 having a collar 26c that can be urged against and contact with the upper surface of the substrate 16; and a collar that is located substantially opposite to the left-side fixed roller 30 and can be urged against and contact with the upper surface of the substrate 16 26d, has a right movable roller 31 that can be brought into contact with the right end edge of the substrate 16 by being urged, and the collars 26a, 26b, 26c,
At 26d, by pressing the print substrate 16 from above,
Since the printing object 16 having the warp can be securely fixed to the holding plate 19, the printing material 16 does not deviate from the printing pattern of the screen 18, and the clearance between the lower surface of the screen plate 18 and the printing material 16 is uniform. As a result, the printing amount of the paste (not shown) can be made uniform anywhere on the printing material 16, and printing bleeding and blurring can be minimized, and there is no deviation from a predetermined position where the printing material 16 having warpage is fixed. The unprintable area generated when the print substrate 16 is pressed from above is represented by the area of the hatched portion M shown in FIG.
It can be kept to a minimum.

Effect of the Invention As described above, the present invention protects the screen plate during printing, and a pair of holding plates provided to face each other to support the edge of the printing material, and a pair of protection plates, between the pair of protection plates, holding the printing material A holding plate and a holding plate are provided on the upper side, and are always located at a lower portion of the printing material. At the time of positioning, the printing material is placed on the holding plate, and the upper surface of the printing material is substantially flush with the upper surface of the protection plate. A table that can be moved up and down until it becomes, a plurality of fixed rollers that can abut against the edge of the printing material, and have a brim that can be urged on the upper surface of the printing material; Has a collar which can be urged against the upper surface of the
A plurality of movable rollers are provided to be able to abut against the edge of the printing material, and the printing material is pressed down from above by a fixed roller brim and a brim of the movable roller to be fixed. As it can be securely fixed to the printed matter, the gap between the screen printing pattern and the printed matter printing pattern is prevented, the amount of clearance between the lower surface of the screen printing plate and the upper surface of the printed matter can be made uniform, and printing blemishes and blurring can be minimized. , The area that cannot be printed when the printing material is pressed from above so as not to be displaced from the predetermined position where the printing material having the warp is fixed can be minimized, so that printing can be performed with higher accuracy, reliability, and reliability. Can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part of a screen printing machine according to an embodiment of the present invention, FIG. 2 is a schematic plan view taken along the line KK in FIG. 1, and FIG. FIG. 4 is a schematic front view, FIG. 4 and FIG. 5 are main part schematic front views showing a state in which the printing material is raised to a predetermined position on the lower surface of the screen plate in FIG. 3, and FIG. FIG. 7 is a schematic front view of a main part of the screen printing machine, FIG. 7 is a detailed view of a main part when a printing medium is raised to a predetermined position on the lower surface of the screen plate in FIG. 6, and FIG. It is a top view. 16 ... Printed material, 17a, 17b ... Protective plate, 18 ... Screen plate, 19 ... Holding plate, 20 ... Table, 25 ... Front fixed roller, 26a-26d ... Collar, 28 ... Rear side Movable roller, 30: Left fixed roller, 31: Right movable roller.

Claims (1)

(57) [Claims] 1. A printing table which is conveyed from one direction by a vertically movable positioning table, and which raises the printing substrate to near a lower surface of a screen plate provided directly above the positioning table. A screen printing machine that prints a printing paste, wherein the positioning table protects the screen plate during printing, and a pair of protection plates provided to face each other to support an edge of the printing object, A holding plate provided between the pair of protection plates, for holding the printing object, and the holding plate provided on the upper side, which is always located at a lower portion of the printing object, and holds the printing object at the time of positioning the printing object. Placed on a plate, the upper surface of the printing material, the table can be raised and lowered until it is substantially the same height as the upper surface of the protection plate, and can be abutted on the edge of the printing material,
A plurality of fixed rollers having a brim capable of being biased on the upper surface of the printing medium, and a brim located at a position substantially opposed to the fixed roller and capable of being biased against the upper surface of the printing medium and abutting thereon; It is provided with a plurality of movable rollers which can be pressed against the edge of the printed material and can be brought into contact therewith, and the printing material is pressed down from above and fixed by the collar of the fixed roller and the collar of the movable roller. Screen printing machine.