JP2001353944A - Stencil printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically regulate rotational phases between plate cylinders in a plurality and thereby to prevent a color shift in printing. SOLUTION: A first plate cylinder 10, a second plate cylinder 11 and an impression cylinder 12 are provided rotatably and rotational phase varying means for varying the respective rotational phases of the first and second plate cylinders 10 and 11 are provided separately, while plate cylinder rotational position detecting sensors and an impression cylinder rotational position detecting sensor which detect the respective rotational positions of the first plate cylinder 10, the second plate cylinder 11 and the impression cylinder 12 are provided separately. A phase difference computing circuit which computes a rotational phase difference between the first plate cylinder 10 and the second plate cylinder 11 from outputs of the rotational position detecting sensors is provided and the rotational phase varying means is controlled so that the phase difference computed by the phase difference computing circuit be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine having a plurality of plate cylinders and capable of performing multicolor printing.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional stencil printing apparatus of this kind.
FIG. 10 is a partial schematic configuration diagram of a stencil printing apparatus. In FIG. 10, the apparatus main body (not shown)
A first plate cylinder 101, a second plate cylinder 102, and an impression cylinder 103 are rotatably arranged therein, and the first plate cylinder 101 and the second plate cylinder 1
02 is the impression cylinder 1 which is about 90 degrees apart from the central angle of the impression cylinder 103.
03, respectively. A plate seat 10 is provided on each outer peripheral surface of the first plate cylinder 101 and the second plate cylinder 102.
1a and 102a are provided.
2a are provided with stencil clamps 101b and 102b for clamping a stencil sheet (not shown).

The outer peripheral surfaces of the first plate cylinder 101 and the second plate cylinder 102 have plate seats 101a and 102a and a spring 104, respectively.
Each of the screens 105 is stretched by using a mesh, and each of the screens 105 is formed of, for example, a mesh structure that allows the passage of ink. First plate cylinder 10
In the internal space of each screen 105 of the first and second plate cylinders 102, middle press rolls 106 and 107 are provided, respectively. Each of the middle press rolls 106 and 107 has a standby position where the screen 105 is not pressed and a press where the screen 105 is pressed. Moved to and from position. During the printing operation, each of the middle press rolls 106 and 107 is located at the press position,
At the pressed position, the screen 105 bulges outward.
The first color ink is applied to the screen 105 on the first plate cylinder 101 side through the middle press roll 106 via the second plate cylinder 102.
The second screen ink is supplied to the screen 105 on the side via the intermediate press roll 107, respectively. On the outer peripheral surface side of the impression cylinder 103, a paper clamp unit 109 capable of clamping the leading end of the printing paper 108 is provided, and the leading end of the printing paper 108 fed from the paper feeding unit 110 is clamped. Release the clamp near the entrance of.

Next, the general operation of printing will be described. The leading edge of a stencil sheet (not shown) produced based on the image data for the first color is attached to the stencil clamping section 101b of the first plate cylinder 101.
Then, the leading edge of a stencil sheet (not shown) produced based on the image data for the second color is clamped by the stencil clamping portion 102b of the second plate cylinder 102, and each screen 1
05 is attached to the outer peripheral surface. Next, the first plate cylinder 101, the second plate cylinder 102 and the impression cylinder 103 are arranged in the directions indicated by arrows in FIG.
Are rotated in synchronization with each other, and in this state, the printing paper 108 is conveyed from the paper feeding unit 110 between the first plate cylinder 101 and the impression cylinder 103. The transported printing paper 108 is clamped by the paper clamping unit 109 of the impression cylinder 103, and passes between the first plate cylinder 101 and the impression cylinder 103 along the outer peripheral surface of the impression cylinder 103.

[0005] During this passage, the intermediate pressing roll 106 presses the screen 105, and the screen 105 bulges outward, and the first color ink image is formed on the printing paper 108 through the perforation of the stencil sheet (not shown). Transferred. First plate cylinder 101
The printing paper 108 that has passed between the printing cylinder 108 and the impression cylinder 103 is transported between the second plate cylinder 102 and the impression cylinder 103,
8 passes between the second plate cylinder 102 and the impression cylinder 103. At the time of this passage, the intermediate press roll 107 is similarly moved to the screen 1
By pressing 05, the ink image of the second color is transferred. Then, the paper clamping unit 109 of the impression cylinder 103 is
When the paper is rotated to the vicinity of the entrance, the paper clamp unit 109 is released, and the unclamped print paper 108 is discharged to a predetermined position by the paper discharge unit 111. As described above, two-color printing is performed.

[0006]

In order to prevent color misregistration of a printed matter in multi-color printing, it is necessary to adjust the rotational phase between the plate cylinders to a predetermined positional relationship. The above-described printing apparatus will be specifically described.
01 and the second plate cylinder 102 are arranged at rotational positions separated by 90 degrees with respect to the central angle of the impression cylinder 103, and in such a rotational position arrangement, the first plate cylinder 101 and the second plate cylinder 102 are arranged.
In order to make the print positions coincide with each other, it is necessary to rotate the print operation during the printing operation while maintaining a 180 ° rotational phase difference. Therefore, the first plate cylinder 101 and the second plate cylinder 10
If a rotational phase shift occurs after the replacement of the two, it is necessary to eliminate both rotational phase shifts. Conventionally, when printing is resumed after replacing the plate cylinder or the like, a printing position shift (color shift) is confirmed by looking at a printed matter obtained by test printing, and an operator is required to check the first plate cylinder 101 and the second plate cylinder 102 By operating the rotation phase varying means and repeating the test printing and the operation of the rotation phase means, the printing position shift (color shift) has been eliminated. Therefore, it takes time and effort to adjust the color shift, and
There is a problem that a lot of printing paper is wasted for trial printing.

Further, in order to set the printing position of a printed material to an appropriate position, it is necessary to match the rotational phases of a plurality of plate cylinders and impression cylinders to a predetermined positional relationship. The above-described method is problematic in that it takes time and effort to optimize the printing position, and that a lot of printing paper is wasted for trial printing.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problem, and an object of the present invention is to provide a stencil printing apparatus capable of automatically adjusting a rotation phase between a plurality of printing drums and preventing color misregistration in printing. And In addition, the present invention can automatically adjust the rotation phase between a plurality of plate cylinders to prevent color misregistration of printing, and also automatically adjust the rotation phase of an impression cylinder with respect to a plurality of plate cylinders to adjust the printing position of a print medium appropriately. It is an object of the present invention to provide a stencil printing apparatus that can be placed at various positions.

[0009]

According to the first aspect of the present invention, there are provided a plurality of plate cylinders which rotate by winding a stencil sheet made on a peripheral surface, an impression cylinder which rotates in a direction opposite to the plurality of plate cylinders, Driving means for rotatingly driving the plurality of plate cylinders and impression cylinders,
A plurality of plate cylinders equipped with stencil paper are rotated in synchronization with the impression cylinder, and a printing medium is conveyed while applying a printing pressure between each of the plate cylinders and the impression cylinders. In a stencil printing apparatus that performs multi-color printing by transferring ink from the stencil sheet attached to each of the plate cylinders to a print medium, and the total number of the plate cylinders is N (N ≧ 2), (N
-1) one or a plurality of rotation phase varying means for varying each rotation phase of the plate cylinder, a plurality of plate cylinder rotation position detection means for detecting each rotation position of the plurality of plate cylinders, and Phase difference calculating means for calculating a rotational phase difference between the plurality of plate cylinders from the rotational positions of the plurality of plate cylinders detected by the plate cylinder rotational position detecting means; and a phase difference calculated by the phase difference calculating means. Control means for controlling one or a plurality of the rotation phase varying means so as to vary the rotation phase between the plurality of plate cylinders.

In this stencil printing apparatus, before starting normal printing, a plurality of plate cylinders are rotated and their rotational positions are detected to measure the phase shift amount of each other, and the phase shift amount is eliminated. The rotation phase varying means is driven in such a manner.

According to a second aspect of the present invention, there are provided a plurality of plate cylinders which rotate by winding a stencil sheet made on the outer periphery, a plurality of impression cylinders which rotate in a direction opposite to the plurality of plate cylinders, and a plurality of the plate cylinders. And a driving unit for driving the impression cylinder to rotate, the plurality of plate cylinders on which the stencil paper is mounted are rotated in synchronization with the impression cylinder, and a printing pressure is applied between each of the plate cylinders and the impression cylinder. In the stencil printing apparatus that performs multi-color printing by transferring ink from the stencil paper mounted on each of the plate cylinders to the print medium in the process of transporting the printing medium while causing the printing cylinder, When the total number including the impression cylinder is M (M ≧ 3),
(M-1) One or a plurality of rotation phase variable means for varying each rotation phase of the plate cylinder and the impression cylinder, and a plurality of plates for detecting each rotation position of one or a plurality of the plate cylinders Cylinder rotation position detection means, a plurality of impression cylinder rotation position detection means for detecting the rotation position of the impression cylinder, and a plurality of the plate cylinder rotation position detection means and a plurality of the cylinders detected by the impression cylinder rotation position detection means. Phase difference calculating means for calculating a rotational phase difference between a plurality of plate cylinders and the impression cylinder from the rotational positions of the plate cylinder and the impression cylinder; and a plurality of the plates corresponding to the phase difference calculated by the phase difference calculating means. 1 to vary the rotational phase of the cylinder and the impression cylinder
Or a control means for controlling a plurality of the rotational phase variable means.

In this stencil printing apparatus, before starting normal printing, a plurality of plate cylinders and impression cylinders are rotated to detect the rotational positions of the cylinders and impression cylinders. The shift amount is measured, and the rotation phase varying means is driven so as to eliminate the phase shift amount.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

1 to 9 show an embodiment of the present invention.
1 is a schematic configuration diagram of a main part of a stencil printing apparatus, FIG. 2 is a schematic configuration diagram of a drum rotating mechanism of a plate cylinder and an impression cylinder, FIG. 3 is a perspective view of a rotation phase varying unit, and FIG. FIG. 5 is a schematic operation flowchart of the rotational phase adjustment, and FIGS. 6A, 6B, and 6C show the rotational positions of the plate cylinder and the impression cylinder in an appropriate rotational phase state. Figure showing
FIG. 7 is a diagram showing the rotational positions of the plate cylinder and the impression cylinder in a rotational phase shift state, FIG. 8 is a time chart in an appropriate rotational phase state,
FIG. 9 is a time chart in a state of rotational phase shift.

Referring to FIG. 1, a stencil printing apparatus 1 includes a printing unit 2, a paper feeding unit 3, and a paper discharging unit 4.

The printing unit 2 has a first plate cylinder (plate cylinder) 10, a second plate cylinder (plate cylinder) 11, and an impression cylinder 12 having substantially the same diameter.
The first plate cylinder 10 and the second plate cylinder 11 are respectively disposed diagonally above left and right of the impression cylinder 12. Specifically, the first plate cylinder 10 and the second plate cylinder 11 have a central angle θ of about 9
Each of the impression cylinders 12 is close to the position on the outer peripheral surface of the impression cylinder 12 which is separated by 0 degrees. The first plate cylinder 10, the second plate cylinder 11, and the impression cylinder 12 are each provided rotatably, and as shown by arrows in FIG. The drums are rotated by the drum rotation mechanism 13 (shown in FIG. 2) so as to have the same peripheral speed. The configuration of the drum rotation mechanism 13 will be described below.

The first plate cylinder 10 and the second plate cylinder 11 are rotatably supported left and right annular frames (particularly without reference numerals).
Are connected by a plate seat 14, and a plate clamp 15 is provided on the plate seat 14. The stencil clamp 15 clamps the leading end of a stencil sheet (not shown).
The front end side of a screen 16 is fixed to each plate seat portion 14, and this screen 16 is used for the first plate cylinder 10 and the second plate cylinder 1
1 is wound around each outer peripheral surface. Each screen 16
The rear end side is stretched to each plate seat portion 14 via a spring 17, and the screen 16 is provided so as to be able to bulge outward against the spring force of the spring 17. Each of these screens 16
Is a mesh structure, for example, and when pressed by an intermediate press roll 18 described below, ink (not shown) passes from the inner surface to the outer surface.

Inside the screens 16 of the first and second plate cylinders 10 and 11, there are provided intermediate press rolls 18, respectively. Each of the intermediate press rolls 18 moves the screen 16 to a standby position separated from the inner surface of the screen 16. It is provided movably between a pressing position where the screen 16 is bulged outward by being pressed from the inner surface and pressed against the first plate cylinder 10 or the second plate cylinder 11. Each of the intermediate press rolls 18 is set to a pressing position during printing, is set to a standby position except during printing, and rotates together with the first plate cylinder 10 and the second plate cylinder 11 at the pressing position. At the time of rotation, a doctor roll (not shown) is used. ) Is used to supply ink (not shown) of a predetermined thickness to the inner surface of the screen 16 by using the gap between the ink and the screen. Also, the first
A first color ink (not shown) is supplied to the plate cylinder 10 side, and a second color ink (not shown) is supplied to the second plate cylinder 11 side. That is, the intermediate press roll 18 has both the function of applying the printing pressure from the inner peripheral side of the screen 16 and the function of supplying ink (not shown) to the screen 16.

A paper clamp section 20 is provided at a predetermined position on the outer peripheral surface of the impression cylinder 12, and the paper clamp section 20 clamps the leading end of a printing paper 21 as a print medium.

The paper supply unit 3 includes a printing paper 21 as a printing medium.
And a primary paper feed roll 23 that conveys only the uppermost printing paper 21 from the paper supply table 22
A pair of secondary paper supply rolls 24 disposed downstream of the primary paper supply rolls 23, and a guide that guides the transport of the printing paper 21 between the secondary paper supply rolls 24 and the impression cylinder 12. And a plate 25. Only the uppermost printing paper 21 is transported to the pair of secondary paper feeding rolls 24 by rotation of the primary paper feeding roll 23, and the transported printing paper 21 is compressed by rotation of the pair of secondary paper feeding rolls 24. It is supplied to the printing unit 2 in synchronization with the rotation of the cylinder 12.

The paper discharging unit 4 is a printing paper 21 on which printing has been completed.
Upper regulating guide portion 26 for guiding the tip of
A paper stripping claw 27 for stripping the printing paper 21 which is not peeled from the paper sheet, and a pair of discharge rollers 28 for conveying the printing paper 21 guided by the upper regulation guide portion 26 or peeled off by the paper stripping claw 27; And a paper discharge table 29 on which the printing papers 21 discharged by the pair of paper discharge rolls 28 are placed in a stacked state.

In FIG. 2, the drum rotating mechanism 13
Has a main motor 30, and a gear 31 is fixed to a shaft 30a of the main motor 30. This gear 31
A gear 32 meshes with the gear 32, and an impression cylinder gear 33 meshes with the gear 32. The impression cylinder gear 33 is fixed to the shaft 12 a of the impression cylinder 12. The outer circumferential gear portion 34a of the first plate cylinder-side cylindrical gear 34 meshes with the impression cylinder gear 33, and the sun gear 35 and the sun gear 35 Three planetary gears 36 located around are arranged. Each of the planetary gears 36 meshes with the sun gear 35 and also meshes with the inner peripheral gear portion 34b of the first plate cylinder-side cylindrical gear 34. The sun gear 35 is fixed to a shaft 37, and a gear 38 (shown in FIG. 3) fixed to the other end of the shaft 37 meshes with a plate cylinder gear 39 (shown in FIG. 3) of the first plate cylinder 10. . Also, impression cylinder gear 3
3 meshes with an outer peripheral gear portion 40a of the first plate cylinder-side cylindrical gear 40, and an inner peripheral gear portion 4 of the first plate cylinder-side cylindrical gear 40.
In 0b, a sun gear 41 and three planetary gears 42 located around the sun gear 41 are arranged. Each of the planet gears 42 meshes with the sun gear 41 and also meshes with the inner peripheral gear portion 40b of the second cylinder-side cylinder gear 40. The sun gear 41 is fixed to a shaft 43, and this shaft 43
A gear 44 (shown in FIG. 3) fixed to the other end of the second plate cylinder meshes with a plate cylinder gear 45 (shown in FIG. 3) of the second plate cylinder 11.

That is, when the main motor 30 rotates,
This rotation is transmitted in the order of the gear 31, the gear 32 and the impression cylinder gear 33, and the rotation of the impression cylinder gear 33 rotates the impression cylinder 12 counterclockwise. The rotation of the impression cylinder gear 33 causes the rotation of the first plate cylinder-side cylindrical gear 34, and this rotation is transmitted to the planetary gear 36 and the sun gear 35 to rotate the shaft 37, and the rotation of the shaft 37 causes the rotation of the first plate cylinder. 10 is rotated clockwise. The rotation of the impression cylinder gear 33 rotates the second plate cylinder-side cylindrical gear 40, and the rotation is transmitted to the planetary gear 42 and the sun gear 41 to rotate the shaft 43. The plate cylinder 11 is rotated clockwise. From the above, the first plate cylinder, the second plate cylinder 11 and the impression cylinder 12
Are rotated in a predetermined rotation direction and synchronously at the same circumferential speed.

The drum rotation mechanism 13 is provided with rotation phase changing means 50 and 51 (shown in FIG. 3) for changing the rotation phases of the first plate cylinder 10 and the second plate cylinder 11, respectively. The rotation phase changing means 50 for the first plate cylinder 10 includes:
As shown in FIG. 3, there is provided a phase shift motor 52 for the first plate cylinder which is a stepping motor, and a gear 53 is fixed to the shaft of the phase shift motor 52 for the first plate cylinder. The gear 53 is meshed with a gear 54.
A worm gear 55 is fixed to the shaft 4. The worm gear 55 meshes with the worm wheel portion 56 of the rotating plate 56, and the rotating plate 56
The planetary gears 36 are rotatably supported. That is, when the first plate cylinder phase shift motor 52 rotates, the three planetary gears 36 rotate around the shaft 35 by this rotation. When the planetary gear 36 rotates, the first plate cylinder-side cylindrical gear 34 does not rotate, and only the sun gear 35 rotates. The rotation of the sun gear 35 causes the first plate cylinder 10 to rotate. The rotation phase of the first plate cylinder 10 changes the rotational phase of the impression cylinder 12 and the second plate cylinder 11. The rotation angle of the first plate cylinder 10 is configured to be controllable by a control unit 71 described below by the number of pulses to the first plate cylinder phase shift motor 52. Further, the rotation phase changing means 51 for the second plate cylinder 11 has the same configuration, and the description is omitted for simplification of the description.

As shown in FIG. 6, a first plate cylinder rotational position detecting sensor (first plate cylinder rotational position detecting means) 60 detects a detection plate 61 which rotates together with the first plate cylinder 10,
When the first plate cylinder 10 is located at the rotation reference position, an H output is output. The second plate cylinder rotation position detection sensor (second plate cylinder rotation position detection means) 62 detects a detection plate 63 that rotates together with the second plate cylinder 11, and outputs H when the second plate cylinder 11 is positioned at the rotation reference position. Output the output. The impression cylinder rotation position detection sensor (impression cylinder rotation position detection means) 64 detects a detection plate 65 that rotates together with the impression cylinder 64, and outputs an H output when the impression cylinder 64 is located at the rotation reference position. As shown in FIG. 2, the encoder 66 detects a detection disk 67 that rotates together with the main motor 30 and outputs a pulse signal at each predetermined rotation angle. That is, the first plate cylinder 10 and the second plate cylinder 1
Since the rotation angle per pulse of the encoder 66 can be calculated by detecting the total number of pulses for one rotation of the impression cylinder 12 and the rotation of the impression cylinder 12, the output pulse of the encoder 66 is determined based on the rotation reference position of the impression cylinder rotation position detection sensor 64. By counting the number to the H output of each sensor 60,62.
The rotational positions of the plate cylinder 10 and the second plate cylinder 11 can be calculated.

Next, a control system related to the rotation phase adjustment of the first plate cylinder 10, the second plate cylinder 11, and the impression cylinder 12 of the stencil printing machine 1 will be described. As shown in FIG. 4, the first plate cylinder rotation position detection sensor 60, the second plate cylinder rotation position detection sensor 6
2. Each output of the impression cylinder rotational position detection sensor 64 and the encoder 66 is guided to a phase difference calculation circuit (phase difference calculation means) 70, and the phase difference calculation circuit 70 The rotational phase difference of the second plate cylinder 11 is calculated. Details of the calculation of the rotational phase difference will be described later. The phase difference data and the pulse signal of the encoder 66 are output to the control unit 71. The control unit 71 includes a timer /
The counter 72 can be controlled and the motor drive circuit 7 can be controlled.
By controlling the motor 3, the driving of each of the main motor 30, the first plate cylinder phase shift motor 52, and the second plate cylinder phase shift motor 57 is controlled. The control unit 71 controls writing and reading of the ROM 74 and the RAM 75 in which various programs are stored, and controls the first plate cylinder 10 and the second plate cylinder 11.
When the operation enters the rotational phase adjustment mode of the impression cylinder 12, the operation flow shown in FIG. 5 is executed. The details of this control will be described in detail in the following operation.

Next, the two-color printing operation of the stencil printing machine 1 will be briefly described. The leading edge of a stencil sheet (not shown) produced based on the image data for the first color is stenciled by the stencil clamp section 15 of the first plate cylinder 10 on the basis of the image data for the second color. The leading end of the base paper (not shown) is clamped by the base paper clamp 15 of the second plate cylinder 11 and attached to the outer peripheral surface of each screen 16. Next, the first plate cylinder 10, the second plate cylinder 11, and the impression cylinder 1 in the directions indicated by arrows in FIG.
2 are rotated synchronously, and in this state, the printing paper 21 is conveyed from the paper feed unit 3 between the first plate cylinder 10 and the impression cylinder 12.
The transported printing paper 21 is clamped by the paper clamping unit 20 of the impression cylinder 12, and is moved along the outer peripheral surface of the impression cylinder 12 to the first position.
It passes between the plate cylinder 10 and the impression cylinder 12.

During this passage, the intermediate pressing roll 18 presses the screen 16 so that the screen 16 bulges outward and the first printing paper 21 is formed through a perforation of a stencil sheet (not shown).
The color ink image is transferred. First plate cylinder 10 and impression cylinder 12
The printing paper 21 passing between the second printing drum 11 and the impression cylinder 1
2, the printing paper 21 passes between the second plate cylinder 11 and the impression cylinder 12. During this passage, the intermediate press roll 18 similarly presses the screen 16 to transfer the second color ink image. When the paper clamp unit 20 of the impression cylinder 12 rotates near the entrance of the paper discharge unit 4, the paper clamp unit 20 releases the clamp, and the unclamped printing paper 21 is discharged by the paper discharge unit 4 to a predetermined position. Is done. As described above, two-color printing is performed.

Next, the operation of adjusting the drum rotation phase will be described. When the drum rotation phase adjustment mode is automatically or manually selected, for example, after the first plate cylinder 101 or the second plate cylinder 102 is replaced and before the printing operation is restarted, as shown in FIG. Then, the main motor 30 is driven (step S100). First plate cylinder 10, Second plate cylinder 11
Then, the rotation speed of the impression cylinder 12 reaches a predetermined speed (YES in step S101), and the H-output of the impression cylinder 12 changes the phase difference measurement signal indicating the start of phase difference measurement to H (step S101).
If YES in step S103) and the phase difference measurement signal becomes L at the next H output of the impression cylinder 12, (YES in step S103)
The measurement of the phase difference ends.

Next, the direction in which the phase shift motors 52 and 57 should rotate and the amount of rotation are calculated from the measurement results (step S104). The calculation direction is as follows.

First, a case where the phase difference is normal will be described with reference to FIGS. The first drum rotation position is detected at a position (position shown in FIG. 6B) rotated 75 degrees with respect to a rotation position (position shown in FIG. 6A) at which the impression cylinder rotation position detection sensor 64 detects the rotation reference position. The output of the sensor 60 rises from L to H. Next, 255 degrees from the rotation reference position of the impression cylinder 12,
The second plate cylinder rotational position detection sensor 6 is rotated 90 degrees from the rotation reference position of the first plate cylinder 10 (the position shown in FIG. 6C).
2 rises from L to H.

Next, a case where the phase difference is not normal will be described with reference to FIGS. As shown in FIG. 9, the second plate cylinder rotation position detection sensor 62 detects the position (FIG. 7) rotated 235 degrees from the rotation reference position of the impression cylinder 12 and 70 degrees from the rotation reference position of the first plate cylinder 10. When the output rises from L to H, the rotational position of the second plate cylinder 11 is
You have advanced 0 degrees. In this case, the second plate cylinder 11
The second plate cylinder phase shift motor 57 is rotated in a direction to delay the rotation of the second plate cylinder with respect to the impression cylinder 12 and by a rotation amount of 20 degrees (steps S105, S106, S107). Then
As shown by a virtual line in FIG. 9, the rotation phase of the second plate cylinder 11 is changed. As described above, since the rotational phase relationship between the first plate cylinder 10 and the second plate cylinder 11 can be automatically adjusted to prevent color misregistration in printing, the color misregistration adjustment takes time and effort as in the related art. In addition, it is possible to solve a problem that a lot of printing paper 21 is wasted for trial printing.

In the above embodiment, the case where the rotational phase of the second plate cylinder 11 is shifted has been described.
Are out of phase with each other.
The first plate cylinder phase shift motor 52 is rotated by a rotation amount corresponding to the phase shift rotation angle in a direction to be delayed or advanced with respect to 2. Also, the first plate cylinder 10 and the second plate cylinder 11
Are out of phase with each other, the first plate cylinder 10
The first plate cylinder phase shift motor 52 is rotated in a direction to delay or advance the impression cylinder 12 with respect to the impression cylinder 12 and by a rotation amount corresponding to the phase shift rotation angle, and the second plate cylinder 11 is moved to the impression cylinder 1.
The second plate cylinder phase shift motor 57 is rotated by a rotation amount corresponding to the phase shift rotation angle in a direction to be delayed or advanced with respect to the second.

In the above embodiment, not only the rotational phase between the first plate cylinder 10 and the second plate cylinder 12 is adjusted, but also the first plate cylinder 10 and the second plate cylinder with respect to the impression cylinder 12. Since the rotation phase of the cylinder 11 is also adjusted, the printing position on the printing paper 21 is adjusted to an appropriate position.

In the above-described embodiment, in the apparatus having the first plate cylinder 10, the second plate cylinder 11, and the impression cylinder 12, the first plate cylinder rotation phase varying means 50 of the first plate cylinder 10 and the second plate cylinder 11
The second plate cylinder rotation phase varying means 51 is provided.
2 and the first plate cylinder rotation phase variable means 50 of the first plate cylinder 10 are provided, and the impression cylinder rotation phase variable means of the impression cylinder 12 and the second plate cylinder 11 Even if the two-plate cylinder rotation phase changing means 51 is provided, the color misregistration adjustment and the proper printing position adjustment can be similarly performed. That is, assuming that the total number of the plate cylinder and the impression cylinder is M (M ≧ 3), it is sufficient to provide (M−1) or more rotation phase variable means for the plate cylinder and the impression cylinder. Further, in order to enable only the rotation phase adjustment between a plurality of plate cylinders, the total number of plate cylinders must be N
Assuming that (N ≧ 2), it is only necessary to provide a rotation phase varying means of (N−1) or more.

According to the above embodiment, the single impression cylinder 1
Although the stencil printing apparatus 1 in which two plate cylinders 10 and 11 are arranged close to two has been described, the present invention can be applied to an apparatus in which three or more plate cylinders are arranged close to each other.
Also, the first plate cylinder 10 and the second plate cylinder 11 have been described as devices in which the center angle of the impression cylinder 12 is 90 degrees, and the apparatus is disposed in the vicinity of the outer peripheral surface. However, the center angle of the impression cylinder 12 is other than 90 degrees. It goes without saying that the same can be applied to a device arranged at a position close to the outer peripheral surface. In this case, assuming that the center angle of the impression cylinder 12 is θ, both plate cylinders 10 and 11 are adjusted in phase so as to be rotationally driven while maintaining a rotation angle phase difference of 2θ.

[0037]

As described above, according to the first aspect of the present invention, in a stencil printing apparatus for performing a plurality of color printing using a plurality of plate cylinders, the total number of plate cylinders is set to N (N ≧ 2). Then
(N-1) one or a plurality of rotation phase varying means for varying each rotation phase of the above-described plate cylinder; a plurality of plate cylinder rotation position detection means for detecting each rotation position of the plurality of plate cylinders; From the rotational positions of the plurality of plate cylinders detected by the plate cylinder rotational position detecting means, a phase difference calculating means for calculating a rotational phase difference between the plurality of plate cylinders, and only the phase difference calculated by the phase difference calculating means. And control means for controlling one or a plurality of rotation phase variable means so as to vary the rotation phase between the plurality of plate cylinders. Therefore, before starting normal printing, the plurality of plate cylinders are rotated to rotate these plate cylinders. The rotational phase is measured by detecting the rotational position, and the rotational phase variable means is driven so as to eliminate the phase deviation. Color shift can be prevented. Therefore, it is possible to solve the problem that it takes time and effort to adjust the color misregistration as in the related art, and that a large amount of printing paper is wasted for test printing.

According to the second aspect of the present invention, there is provided a stencil printing apparatus for performing a plurality of color printings using a plurality of plate cylinders, wherein the total number including the plate cylinder and the impression cylinder is M (M ≧ 3). (M-1)
One or a plurality of rotation phase varying means for varying each rotation phase of the plate cylinder and the impression cylinder, a plurality of plate cylinder rotation position detection means for detecting each rotation position of the plurality of plate cylinders, and a rotation position of the impression cylinder A plurality of plate cylinder rotational positions detecting means for detecting a plurality of plate cylinder rotational positions and a plurality of plate cylinders and pressures from rotational positions of the plurality of plate cylinders and impression cylinders detected by the plurality of plate cylinder rotational position detecting means and the rotational position of the impression cylinder. Phase difference calculating means for calculating a rotational phase difference between cylinders, and one or more rotational phase varying means for varying the rotational phase of a plurality of plate cylinders or impression cylinders by the phase difference calculated by the phase difference calculating means Control means for controlling the number of plate cylinders and impression cylinders by rotating the plate cylinders and impression cylinders and detecting their rotational positions before starting normal printing. Measurement of the phase shift of the Since the changing means is driven, the rotational phase between the plurality of plate cylinders can be automatically adjusted to prevent color shift of printing, and the rotational phase of the impression cylinder with respect to the plurality of plate cylinders can also be automatically adjusted to adjust the printing position of the print medium. Can be in the proper position.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a schematic configuration diagram of a main part of a stencil printing apparatus.

FIG. 2 shows an embodiment of the present invention, and is a schematic configuration diagram of a drum rotating mechanism of a plate cylinder and an impression cylinder.

FIG. 3 is a perspective view of a rotation phase changing unit according to the embodiment of the present invention.

FIG. 4 is a circuit block diagram showing one embodiment of the present invention and relating to rotation phase adjustment of a plate cylinder and an impression cylinder.

FIG. 5 is a schematic operation flowchart of rotation phase adjustment, showing one embodiment of the present invention.

FIG. 6 shows an embodiment of the present invention, wherein (a), (b),
(C) is a diagram showing the rotational positions of the plate cylinder and the impression cylinder in an appropriate rotational phase state.

FIG. 7 is a view showing one embodiment of the present invention and showing respective rotational positions of a plate cylinder and an impression cylinder in a rotational phase shift state.

FIG. 8 is a time chart showing an embodiment of the present invention and in a proper rotation phase state.

FIG. 9 is a time chart showing an embodiment of the present invention, in a state of rotational phase shift.

FIG. 10 is a schematic configuration diagram of a main part of a conventional stencil printing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 2 Printing part 3 Paper supply part 4 Paper discharge part 10 1st plate cylinder (plate cylinder) 11 2nd plate cylinder (plate cylinder) 12 impression cylinder 21 Printing paper (print medium) 50 1st plate cylinder rotation phase Variable means 51 Second plate cylinder rotation phase variable means 60 First plate cylinder rotation position detection sensor (First plate cylinder rotation position detection means) 62 Second plate cylinder rotation position detection sensor (Second plate cylinder rotation position detection means) 64 Impression cylinder rotation position detection sensor (impression cylinder rotation position detection means) 70 Phase difference calculation circuit (Phase difference calculation means) 71 Control unit

Claims (2)

[Claims] 1. A plurality of plate cylinders which rotate by winding a stencil sheet made on a stencil around an outer peripheral surface, an impression cylinder which rotates in a direction opposite to the plurality of plate cylinders, and a rotational drive of the plurality of plate cylinders and the impression cylinder. Drive means, and a plurality of plate cylinders on which the stencil sheet is mounted are rotated in synchronization with the impression cylinder, and a printing medium is applied while applying a printing pressure between each of the plate cylinders and the impression cylinder. In a stencil printing apparatus that performs multi-color printing by transferring ink from the stencil sheet mounted on each of the plate cylinders to a printing medium during the transfer process, the total number of the plate cylinders is N (N ≧ N If 2), one or a plurality of rotation phase varying means for varying each rotation phase of the plate cylinder (N-1) or more, and a plurality of plate cylinder rotation positions for detecting each rotation position of the plurality of plate cylinders Detecting means; and the plurality of plates detected by the plurality of plate cylinder rotational position detecting means. Phase difference calculating means for calculating a rotational phase difference between a plurality of plate cylinders from the rotational position of the cylinder; and varying the rotational phase between the plurality of plate cylinders by the phase difference calculated by the phase difference calculating means. A stencil printing apparatus comprising: a control unit for controlling one or a plurality of the rotation phase changing units. 2. A plurality of plate cylinders, which rotate by winding a stencil sheet made on a stencil around an outer peripheral surface, an impression cylinder rotating in a direction opposite to the plurality of plate cylinders, and a rotational drive of the plurality of plate cylinders and the impression cylinder. Drive means, and a plurality of plate cylinders on which the stencil sheet is mounted are rotated in synchronization with the impression cylinder, and a printing medium is applied while applying a printing pressure between each of the plate cylinders and the impression cylinder. Conveying, in a stencil printing apparatus that performs multi-color printing by transferring ink from the stencil sheet mounted on each of the plate cylinders to a print medium in the conveying process, including the plate cylinder and the impression cylinder Assuming that the total number is M (M ≧ 3), one or a plurality of rotation phase variable means for varying each rotation phase of the plate cylinder and the impression cylinder of (M−1) or more, and one or more of the plate cylinders A plurality of plate cylinder rotational position detecting means for detecting each rotational position; and detecting a rotational position of the impression cylinder. A plurality of printing cylinder rotational position detecting means, and a plurality of printing cylinders from the plurality of plate cylinder and the rotational positions of the impression cylinder detected by the plurality of plate cylinder rotational position detecting means and the impression cylinder rotational position detecting means. A phase difference calculating means for calculating a rotational phase difference between the cylinder and the impression cylinder; and 1 or a method for varying the rotational phase of the plurality of plate cylinders or the impression cylinder by the phase difference calculated by the phase difference calculating means. A stencil printing apparatus, comprising: a control unit for controlling the plurality of rotation phase changing units.