JPH04138253A - Gravure cell carving method and its device - Google Patents

Abstract

PURPOSE:To reduce variation in color tone by a method wherein a gravure cell is carved by a specific pitch over one scan line, and the gravure cell is carved by the specific pitch over a new scan line adjacent to the scan line over which carving of the gravure cell is completed by a phase difference set to specific conditions. CONSTITUTION:Gravure cells C1-C4 are carved on a surface of a gravure cylinder by a interval of a specific pitch P along the surface of the gravure cylinder over one scan line. then, a scan line direction phase difference among the gravure cells C1-C4 with each other in mutual adjacent scan lines over a new scan line adjacent to each other shifted by a distance P/(m**2+1) (m is an integer of 2 or more) along a sub scan direction from this scan line, is set to P.m/(m**2+1) or P.(1-m/(m**2+1)), and the gravure cells C1-C4 are carved by the interval of the specific pitch P. Then, this procedure is repeated. Resolution can be equalized thereby both in a main scan direction and in the sub scan direction, and an image can be reproduced by a uniform color tone.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electronic gravure cell engraving method and apparatus for engraving a gravure cell on each of a plurality of scanning lines of a gravure cylinder. [Prior Art] Conventionally, the following technique has been proposed for engraving a gravure cell on the surface of a gravure cylinder (Japanese Patent Publication No. 19772/1983). That is, based on a square basic cell pattern consisting of gravure cells having cell pitches at equal intervals in the main scanning direction (direction along the rotation direction of the gravure cylinder) and sub-scanning direction (direction parallel to the central axis of the gravure cylinder), A plurality of orthogonal cell patterns are considered by compressing the pitch of each cell in the main scanning direction and expanding it in the sub-scanning direction, or by expanding it in the main scanning direction and compressing it in the sub-scanning direction. Then, a plurality of gravure cylinders each having a different orthogonal cell pattern are created as gravure cylinders for representing color-separated images of the original image. Moreover, the mutual positional relationship of orthogonal cell patterns in each gravure cylinder is adjusted to 1/1/2 of the compressed or expanded cell pitch.
Each gravure cell is formed so as to be shifted by two in the main scanning direction and in the sub-scanning direction. In this way, gravure cells are engraved on the surface of each gravure cylinder in a so-called orthogonal face-centered cell pattern in which one gravure cell is located at the face center of the orthogonal cell pattern. The compressed or expanded cell pitch in the main scanning direction and the cell pitch in the sub-scanning direction in each gravure cylinder are related so that a common divisor exists between the two cell pitches. Specifically, when the cell pitch of the cell pattern is expressed as (pitch in the main scanning direction) x (pitch in the sub-scanning direction), a square basic cell pattern with a pitch of 5p x 5p (p is a predetermined unit length) is prepared. The gravure cylinder has an orthogonal cell pattern with a pitch of 4px6p, which is compressed in the main scanning direction and expanded in the sub-scanning direction, and 6pX in which the pitch is expanded in the main scanning direction and compressed in the sub-scanning direction.
A gravure cylinder having an orthogonal cell pattern with a pitch of 4p was prepared.

[Problem to be solved by the invention]

However, the following problems have been pointed out in the above conventional technology. In other words, due to the fact that the cell pitch of the square basic cell pattern is compressed or expanded, the cell pitch in the main scanning direction and the cell pitch in the sub-scanning direction in each gravure cylinder are inevitably different, and the resolution in the main scanning direction and the sub-scanning direction is different. Not only is there a difference, but the relationship between one ink-applied area in a printed matter and the four nearest ink-applied areas surrounding it is different from the one ink-applied area to each of the above-mentioned nearest inked areas in each printed matter. The two line segments are not orthogonal. For this reason, the distribution of gravure cells (that is, the mesh arrangement) in the gravure cylinder and, by extension, the isotropy of the ink adhesion area in the printed matter are impaired, and the expression of uniform color tone of the printed matter is adversely affected. By the way, in offset printing that uses a planographic plate without unevenness, in order to avoid such problems, when arranging halftone dots, a line segment connecting one halftone dot and the nearest halftone dot centered on this halftone dot is usually used. The halftone dots are made perpendicular to each other, and the halftone dots are formed at different screen angles for each plate. However, in gravure printing using a gravure cylinder using an electronic engraving process, an engraving knife is pressed against a rotating cylindrical gravure cylinder to engrave a gravure cell for each scanning line. It is difficult to engrave each gravure cell so that each plate has an array pattern with different screen angles because the calculation of the engraving position is complicated. For this reason, as described above, a method has been used in which the cell pitch is compressed or expanded depending on the scanning direction. In the above conventional technology, as shown in FIG.
When multicolor printing is performed using a gravure cylinder having an orthogonal centering cell pattern (hatched cells in the figure) with a pitch of p and a gravure cylinder having an orthogonal centering cell pattern (white cells in the figure) having a pitch of 6p x 4p, In the printed matter, for example, as shown by symbol A in the figure, the ink adhesion area where diagonal line cells and white cells overlap at the center appears in a square pattern (pitch = 12p) that is an enlargement of the square basic cell pattern. Therefore, there is also the problem that moire fringes and color tone changes are likely to occur in printed matter. Even if one of the two orthogonal center cell patterns is used as a square basic cell pattern, a square pattern that is an enlarged square basic cell pattern will of course appear in the printed matter. The present invention was made in order to solve the above problems, and the present invention engraves a gravure cell so that the mesh on the gravure cylinder is arranged in the same direction with respect to each scanning direction, and also prevents changes in tone in multicolored gravure printed matter. The aim is to reduce (Means for Solving the Problems) The procedure according to the first invention for achieving the above object is to press an engraving knife for gravure cell engraving onto the surface of a cylindrical gravure cylinder rotating around a central axis. In the gravure cell engraving method, in which gravure cells are sequentially engraved at intervals of a predetermined pitch P on each of a plurality of scanning lines along the rotational direction of a gravure cylinder, the engraving blade moves toward the gravure cylinder each time the gravure cylinder rotates once. While moving the engraving knife by a distance of P/(m-2+1) (m is an integer of 2 or more, and the operator' represents a power) along the sub-scanning direction parallel to the central axis of the Engraving a gravure cell by pressing the engraving knife against the surface of a gravure cylinder at a predetermined pitch P over one scanning line among a plurality of scanning lines;
The scanning line direction phase difference between gravure cells in adjacent scanning lines is P-m/ (m" 2+1) or P・(1-
m/(m"2+1)), and with the set phase difference, the engraving blade is applied to the surface of the gravure cylinder at a predetermined pitch P over a new scanning line adjacent to the scanning line where the engraving of the gravure cell has been completed. The gist of the second invention is to press the gravure cylinder against the central axis, as shown in the block diagram of Fig. 1. An engraving knife B for gravure cell engraving is held on a tool rest BH facing the surface of the GC and movable along the sub-scanning direction parallel to the central axis of the cylinder, and the engraving knife B is directed toward the surface. A gravure cell engraving device comprising an engraving control means MO that sequentially engraves a gravure cell on each of a plurality of scanning lines along the rotational direction of the gravure cylinder GC by controlling drive in the incision direction and the sub-scanning direction, respectively. The engraving control means MO includes a detection unit Ml that detects the rotational state of the rotating gravure cylinder GC, and a detection unit Ml that controls the engraving blade B from the gravure cylinder GC every time the gravure cylinder GC rotates once, based on the detection result. A knife movement control unit M2 that moves by a distance of P/ (m=2+1) (m is an integer of 2 or more, and the operator "represents a power") along a sub-scanning direction parallel to the central axis, and the engraving knife A control signal for pressing B onto the surface of the gravure cylinder 00 at a cutting period of a predetermined pitch P is sent to the detection unit M.
a control signal output section M3 that outputs an output based on the detection result of step 1; and a control signal output section M3 that receives the control signal and drives the engraving blade B in the incision direction to drive the engraving blade B at intervals of the predetermined pitch P over one scanning line. The incision direction drive control unit M4 presses against the surface of the gravure cylinder 00 to engrave the gravure cells, and the scanning line direction phase difference between the gravure cells in adjacent scanning lines is determined by P-m/(m'2+1) or P・(
Phase difference setting section M5 to set to 1-m/(m"2+1))
and an output that changes the output timing of the control signal by the control signal output section M3 after one rotation of the gravure cylinder GC based on the set phase difference and the rotational state of the gravure cylinder GC detected by the detection section M1. The gist thereof is that the timing change section M6 is provided. In the third invention, in addition to the structure of the second invention, the carving blade B has two cutting edges intersecting at a predetermined cutting angle at the tip thereof, and a tool rest for holding the carving blade B. BH maintains the bisector of the bevel angle so as to pass through the center axis of the gravure cylinder GC or its vicinity, and the rake face surrounded by the two bevels through the bisector. The gist thereof is to hold the engraving blade B at a predetermined angle as the center with respect to the scanning line. Here, in order to control the movement of the engraving knife B along the sub-scanning direction for each rotation of the gravure cylinder GC by the knife movement control unit M2, the engraving that had been stopped until then after the completion of one rotation of the gravure cylinder GC must be controlled. Cutting tool B to P/(m“2+
1) or continuously move the engraving knife B so that it moves by P/(m-2+1) during one rotation of the gravure cylinder GC, which can be selected as appropriate. Further, the predetermined pitch P of the gravure cells on the surface of the gravure cylinder refers to the pitch along the surface of the gravure cylinder. Therefore, even if the pitch P is the same, the number of gravure cells engraved over one scanning line differs depending on the diameter of the gravure cylinder. Furthermore, the scanning line direction phase difference between gravure cells in adjacent scanning lines refers to the deviation in the main scanning direction between gravure cells engraved at a predetermined pitch P in each scanning line. Further, m is not particularly limited as long as it is an integer of 2 or more, but from the viewpoint of shortening the calculation time required to calculate the amount of movement etc., it is desirable that m=2. In addition, when holding the engraving blade B via the tool post BH so that the bisector of the cutting edge angle passes through the central axis of the gravure cylinder GC or its vicinity, the bisector of the cutting edge angle must be It is preferable to hold the engraving knife B so that the engraving knife B passes through the central axis of the gravure cylinder GC, because it facilitates adjustment of the knife set, design of the flank, and avoidance of interference between the flank and the inner surface of the engraved gravure cell. . Then, the bisector of the cut neck angle is the gravure cylinder GC.
When passing near the center axis of the center axis, consider the degree of separation from the center axis, the shape of the flank, etc., and make sure that the flank does not interfere with the inner surface of the engraved gravure cell. . (Function) The first invention having the above configuration includes the steps of engraving gravure cells on the surface of a rotating gravure cylinder in each of a plurality of scanning lines at a predetermined pitch P along the surface of the gravure cylinder. Every time the gravure cylinder rotates, the engraving blade is moved along the sub-scanning direction by P/(m'2+1)
While moving by a distance of , the engraving knife is first pressed against the surface of the gravure cylinder at the predetermined pitch P over one of the scanning lines to engrave the gravure cell. At this time, the engraving knife, which is stopped in the sub-scanning direction, is pressed against the surface of the gravure cylinder while the gravure cylinder remains in the stopped position for one rotation of the gravure cylinder, and then the engraving knife is moved along the sub-scanning direction by P/(m"2+1) During the movement, the engraving knife is moved continuously so that it moves by P/(m'2+1) along the sub-scanning direction during one revolution of the gravure cylinder GC. It is sufficient to press the engraving knife against the surface of the gravure cylinder during the movement period. In this way, the engraved scanning line of the gravure cell is
A state is established in which engraving of gravure cells in adjacent scanning lines separated by a distance of 2+1) can be started. Then, the scanning line direction phase difference between the gravure cell of the engraved scanning line and the gravure cell of the new scanning line adjacent to this scanning line is determined as P-m/(m"2+1) or P・(1-m
/ (m'2+1)), and press the engraving blade against the surface of the gravure cylinder at a predetermined pitch P over a new scanning line to engrave the gravure cell. When printing using a gravure cylinder with a gravure cell engraved in this way, the ink adhesion pattern of the printed matter, which corresponds to the developed view of the gravure cylinder surface, will be different from the X-axis along the scanning line and the Y-axis along the sub-scanning direction. In the orthogonal locus search system, the arrangement pattern is as shown in FIG. The centers of each ink adhesion portion of this ink adhesion pattern are distributed on a straight line a expressed by the following equation (2) at intervals of distances expressed by the following equations (2) and (2). Straight line a: Y=kl・X+α (α is a constant) ...0217
m...■L"
2” (, (P/ (m' 2+ 1))
'2+(P-m/(m'2+1))'2...■ For example, the nearest ink adhesion parts C2 and C3 to the ink adhesion part represented by the symbol CI in the figure are located at the center of this ink adhesion part C1. It will be located at the intersection of the passing straight line a and the scanning line adjacent to the scanning line on which the ink adhering portion C1 is located, and the distance therebetween will be L expressed by the above formula (2). Also, m counting from the scanning line where the ink adhesion portion C1 is located.
(=2) Ink adhesion portion C located on each scanning line separated by a book
4. Coordinates of center of C5 (X4.Y4), (X5.Y5)
tt and the coordinates of the center of the ink adhering portion C1 are (0, 0), respectively, and are expressed as follows. X4=P・(1-m-2/ (m”2+1))Y4=
-P -m/ (m-2+1)X5=P・ (-1+
m'2/ (m'2+1))Y5=P-m/
(m-2+1) Therefore, the distance between the ink adhesion part C1 and the ink adhesion part C4°C5 is respectively P・((m-2+1))'1/2) (m=2+1), and the ink adhesion part It is equal to the distance wiL between C1 and the ink adhering portion C2゜C3, and as can be seen from the above coordinate values, the ink adhering portion C4゜C5 is located point symmetrically with respect to the ink adhering portion CI, and each The center of the ink adhesion area is distributed by distance on a straight line expressed by the following formula (2). Straight line b = Y = 2 x 10 β (β is a constant) River ■ = = -m
...■Direct!
Since the product of 2 for the slope of b and 1 for the slope of straight line i1a is -1, straight line gb is a straight line that is perpendicular to straight line a at the center of ink adhesion WCI. Also, the distance between the ink adhesion part C1 and the ink adhesion parts C2 and C3 is the same as that of the ink adhesion part C1 and the ink adhesion parts C4 and C5.
Since it is equal to the distance between
is the ink adhesion part C1 as well as the ink adhesion parts C2 and C3.
This is the closest ink adhesion area to the area. In other words, the first invention is a straight line a in an orthogonal relationship,
The ink adhesion parts are distributed at the intersections of b, and the four ink adhesion parts nearest to a certain ink adhesion part are distributed equidistantly from the ink adhesion part, that is, equidistantly. Furthermore, from a certain scanning line in the sub-scanning direction (m'2+1) grain scanning lines, that is, from the certain scanning line to (P/ (m-2+
1) The same gravure cell pattern is formed on the surface of the gravure cylinder in scanning lines separated by x (m=2+1)=p, as shown in FIG.
A square pattern appears. A second invention made in practicing the gravure cell engraving method according to the first invention is to drive an engraving blade B held on a tool rest BH in the direction of the cut so as to face the surface of a rotating cylindrical gravure cylinder GC. When doing so, the detection unit M
1, the rotational state of the gravure cylinder GC is detected, and a control signal for pressing the engraving blade B against the surface of the gravure cylinder 00 at a cutting period of a predetermined pitch P is output from the control signal output section M3 based on the detection result. Note that, as shown in FIG.
If the configuration is such that the control signal is inputted to
The above-mentioned predetermined pitch P is obtained by superimposing the pressing strength of the engraving knife B.
A control signal with a cutting period of 1 is output. Upon receiving this control signal, the incision direction drive control section M4 is activated, and the engraving blade B is pressed against the surface of the gravure cylinder 00 at a predetermined pitch P to engrave the gravure cell over one scanning line. On the other hand, based on the detection result (rotational state of gravure cylinders G and C) detected by the detection unit M1, the blade movement control unit M2 moves the engraving blade B along the sub-scanning direction every time the gravure cylinder GC rotates once. Since it is moved by a distance of P/(m"2+1), the cutting direction drive control unit M
The scanning line and P/ (m” 2+1) where the engraving of Le is completed in the gravure by the above-mentioned pressing of the engraving knife B in step 4.
A state is reached in which engraving of gravure cells in adjacent scanning lines separated by a distance of . When engraving a gravure cell in a new scanning line adjacent to the scanning line on which the gravure cell has been engraved, the phase difference setting unit M
The phase difference in the scanning line direction between the gravure cells set by No. 5, that is, P-m/ (m' 2+1) or P・(1-m
/ (m” 2+1)) and the rotational state of the gravure cylinder GC detected by the detection unit Ml, the output timing change unit M6 changes the output timing of the control signal by the control signal output unit M3. Engraved scan line of cell and P/(m62
In new scanning lines that are adjacent to each other with a distance of be done. As a result, in this new scanning line, P-m in the scanning line direction with respect to the gravure cell of the already engraved scanning line.
/(m-2+1) or P・(1-m/(m2+1)
) The gravure cell is engraved with a phase difference of
Gravure cells are formed in the same pattern with a predetermined pitch P for each (m'2+1) grain scanning line. In this case, m is 2
In this case, the gravure cell is engraved with the same pattern at a predetermined pitch P at a period of five scanning lines. Therefore, when printing using a gravure cylinder with a gravure cell engraved in this way, the ink adhesion pattern on the printed matter will have the relationship as explained in the first invention.
That is, in the above coordinate system, two straight lines (
Each ink adhering portion is distributed on straight lines a and b), and the distances between any gravure cell and its four nearest gravure cells are the same (L). A third invention which adds a configuration to the second invention is such that the bisector of the cutting angle where the two cutting heads of the engraving knife B intersect passes through the central axis of the gravure cylinder GC or its vicinity. while maintaining the gravure cylinder at a predetermined angle with respect to the scanning line of the gravure cylinder GC,
By holding the engraving knife B on the tool rest BH, the shape of the gravure cell to be engraved with the engraving knife B can be determined as shown in Fig. 3 (
A) It can be a parallelogram with diagonals along the scanning line, as shown by the solid and broken lines in A). As a result, the part surrounding the gravure cell on the surface of the gravure cylinder, that is, the so-called edge part that the doctor blade comes into contact with when the ink is deposited, has a diagonal line along the scanning line, as shown by the solid line or broken line in FIG. 3(B). The degree of zigzag shape is reduced compared to the conical part when a diamond-shaped (conventional gravure cell shape) gravure cell is engraved. Additionally, it is generally done to increase the engraving depth and area of the gravure cell in order to deepen the color tone in printed matter, but if the shape of the gravure cell is a parallelogram as described above, the following results will be obtained. play an action. That is, when increasing the size of the diamond-shaped conventional gravure cell shown by the solid line in FIG. 3(B) as shown by the broken line,
There is a problem in that one of the two sets of opposite sides of each gravure cell first coincides with the opposite side of the adjacent gravure cell, and the edge part of that part disappears, and the isotropy of the edge part collapses. On the other hand, when the parallelogram-shaped gravure cell shown by the solid line in FIG. This allows the engraving depth and area of the gravure cell to be expanded while leaving the cone portion intact. In particular, if the inclination angle θ of the rake face with respect to the scanning line of the gravure cylinder GC is an angle that satisfies tanθ=1/m, as shown by the solid line in FIG. 3(A), the parallelogram gravure cell It is possible to engrave a gravure cell in which one opposite side is parallel to the straight line a, and the constriction becomes a straight line, which is preferable. It is avoided that one of the two sets of opposite sides of each gravure cell coincides first, and the isotropy of the constriction part can be maintained. Example 1 Next, an example of the present invention will be described based on the drawings. FIG. 4 is a block diagram showing a schematic configuration of the gravure cell engraving device of this embodiment. As shown in FIG. 4, the gravure cell engraving device 1 of the embodiment
A cylindrical gravure cylinder 2 is rotatably supported around its central axis, and a tool rest 6 holding an engraving knife 4 for gravure cell engraving is moved in a sub-scanning direction parallel to the central axis of the gravure cylinder 2. An engraving part 1o that is moved along the
An engraving control section 20 that controls the drive of the engraving knife 4 in the direction of cutting toward the surface of the gravure cylinder 2 and controls the drive of the tool rest 6 in the sub-scanning direction, and a gradation signal for cells from the gradation signal data of the original image. It also includes a gradation information storage section 40 that creates and stores data. The engraving unit 10 has a main shaft motor 12 connected to the central axis of the gravure cylinder 2, and a tool rest 6 screwed into a ball screw 14 which is rotatably supported by a bearing (not shown) and arranged along the sub-scanning direction. Subshaft motor 1 for moving the turret
6, and a main shaft encoder 2a for detecting the rotational state of the gravure cylinder 2 (rotational position 2 rotational speed, etc.) and a sub-shaft encoder 14a for detecting the position of the tool rest based on the rotational state of the ball screw 14. It is configured to be attached to the opposite side of each motor 12, 16, and rotates the gravure cylinder 2 based on a control signal from an engraving control section 20, which will be described later, and also controls the tool rest 6 through the rotation of the ball screw 14. Move along the sub-scanning direction. The tool rest 6 has a built-in actuator (not shown) that drives the engraving tool 4 in a direction toward the surface of the gravure cylinder 2 (in the cutting direction), and drives the engraving tool 4 based on a control signal from the engraving control section 20. Press it against the surface of the gravure cylinder 2. As shown in FIG. 5, the engraving knife 4 has two cutting teeth 4a intersecting at a predetermined cutting surface angle at its tip, and is held on the tool rest 6 in the following manner. The bisector 4b of the cutting surface angle between the two cuts 94a of the engraving blade $4 is maintained along the scanning line of the gravure cylinder 2, and 18
As shown in Figure 6, the bisector 4b is the gravure cylinder 2
is maintained so that it passes through the central axis axis 0 of. Two pieces @
The rake face 4c surrounded by 4a rotates the bisector 4b with respect to the direction of scanning MS of the gravure cylinder 2, as shown in FIG. 7, which is a view from the direction of arrow Z in FIG. It is rotated by an angle θ (tan θ=1/m) about the central axis. Therefore, when the engraving knife 4 is pressed against the surface of the rotating gravure cylinder 2, as shown in FIGS. 7 and 3(A).
As shown in FIG. 2, a parallelogram-shaped gravure cell having diagonal lines along the scanning line S and one opposite side parallel to the straight line a is engraved on the surface of the gravure cylinder 2. Incidentally, a carbide tip 4d is fixed to the tip of the engraving knife 4, as shown in FIGS. 5 and 6. Further, the flank 4e of the engraving blade 4 is formed so as not to interfere with the inner surface of the gravure cell C that is engraved on the surface of the gravure cylinder 2, as shown in FIG. By the way, the gradation information storage unit 40 that creates and stores the gradation signal data for cells shown in FIG. a cell gradation data interpolation unit 44 that creates cell gradation data at the center point of the cell by interpolation; and a cell gradation data storage unit 46 that stores the created cell gradation data.
Equipped with. The original image gradation data is data representing a color-separated image, and as shown in Fig. 2, the original image is divided into squares at a pitch PO which is finer than the gravure cell pitch, which will be described later, that is, the engraving pitch P of the ink-applied area in the printed matter. grid points (Gll of Gij column, G12...Glj,
G21 in column G2j. G22...G2j, Gi
Gil in column j. Gi2...Gij) is data representing each color separated image. The cell gradation data interpolation unit 44
In a coordinate system consisting of an axis and a Y axis along the sub-scanning direction,
Based on the difference between the coordinates of four adjacent grid points arranged in a square grid and the coordinates of the center point of the cell of interest, the ink is determined as follows from the original image gradation data of each grid point. Interpolate the cell gradation data at the center point of the attachment part. Let the center coordinates of the gravure cell C1 in FIG. 2 be (X.y), and each of the four lattice points G2 around this gravure cell
5. G26. G35. The coordinates of G36 are (
0゜0), (PO,O), (0,PO),
(PO, PO), and each grid point G25. G26.
G35. Each G36 original gradation data is converted to G25.
．． g26. Let g35°g36. The cell gradation data c1 at the center point of the gravure cell C1 is obtained by interpolation using the following equation. cl= g25x (1-x/PO) ・ (1-y/PO)
+g26X (x/PO) ・ (1y/PO)+
g35X (1-x/PO) ' (y/PO)
+g36X (x/PO) · (y/PO) Then, the cell gradation data interpolated for each cell in this way is stored in the cell gradation data storage section 46. The engraving control unit 20, which controls the engraving knife 4, the turret 6, etc., is implemented by a well-known CPU 31. ROM32. RAM33. An electronic control unit 30 configured as a logic operation circuit by interconnecting an input boat 34 and an output boat 35 via a common bus 36, and a main shaft encoder 2a for detecting the rotational state of the gravure cylinder 2, and detecting the detection signal thereof. A clock circuit 22 that creates and outputs a clock original signal based on
and a drive control signal (
The engraving knife drive circuit 24 amplifies the engraving signal) and outputs it to this actuator, and the engraving knife drive circuit 24 is connected to the sub-shaft motor 16 for moving the turret connected to the ball screw 14, and outputs the drive control signal for the turret 6 (the engraving signal) ) is connected to the main shaft motor 12 connected to the gravure cylinder 2 and amplifies the rotation control signal of the gravure cylinder 2 and outputs it to the main shaft motor 12. A cylinder drive circuit 28 is provided. A clock circuit 22. A sub-shaft encoder 14a for detecting the current position of the tool rest and a gradation information storage section 40 for creating and storing gradation data for cells are connected, and the clock circuit 22 is connected to the rotational state of the gravure cylinder 2. The current position detection signal of the tool rest 6 along the sub-scanning direction of the gravure cylinder 2 is sent from the sub-axis encoder 14a, and the cell gradation data is sent from the gradation information storage section 40.
Each is input to this electronic control device 30. On the other hand, the output boat 35 is connected to each of the drive circuits described above, and a control signal suitable for each drive circuit is output. Next, the engraving blade drive control routine performed by the gravure cell engraving device 1 of this embodiment having the above-described configuration will be described based on the flowchart of FIG. 8. In addition, in this explanation, when the value of the ratio in the formula representing the movement amount in the sub-scanning direction of the engraving blade for engraving the gravure cells and the phase difference in the scanning line direction between the gravure cells in adjacent scanning lines is 2. I will explain about it. Therefore, the interval between adjacent scanning lines is P15, and the phase difference in the scanning line direction between gravure cells in adjacent scanning lines is 2P15. The engraving blade drive control routine shown in FIG.
This process is executed after clearing internal registers, etc., and is repeated from when an engraving start signal is output from an operation panel (not shown) until all gravure cell engraving in the gravure cylinder 2 is completed. As shown in FIG. 8, this engraving blade drive control routine, following the above-mentioned initial processing, first proceeds to step 105 (hereinafter, step is simply referred to as S). At 115, 125, and 135, the scanning line counter CN (
(described later) is 0 (S105). Determining whether the value of the scanning line counter CN is 1 (S115)
, determine whether the value of the scanning line counter CN is 2 (S125
), determining whether the value of the scanning line counter CN is 3 (S11
5). This scanning line counter CN is a scanning line counter CN whose scanning line engraves the gravure cell from the end of the gravure cylinder (N
-1)xs+1) wood grain (i is a positive integer), and its initial value CN=O is set in the above initialization process. If it is determined that CN=O in 5105, the scanning line is the scanning line of the ((i-1)X5+1) grain from the end of the gravure cylinder (here, i is the initial value 1, that is, the scanning line of the first grain) It is judged that. In order to generate an engraving signal (H dynamic waveform signal) representing the pressing amount of the engraving blade 4 on this scanning line, the reference start address BO for reading out the drive waveform data stored in advance in the ROM 32 is set as follows. settings (S140). As shown in FIG. 9, a predetermined address area A of the ROM 32
In R (drive waveform data storage address area), drive waveform data f1 to fN representing a triangular wave of engraving pitch P are stored in advance. Also, in 80M32, ((i-1)
An address correspondence map is also stored in which the scanning line number represented by x5+1) is associated with the reference start address. The reference start address is an address for starting reading drive waveform data from the ROM 32. At 5140, the reference start address BO is read from the address correspondence map based on the scanning line number represented by ((i-1)X5+1). Immediately after the processing of this routine is started, as described above, the value of the scanning line counter CN is the initial value 0 due to the initial processing, so a determination is made in 5105, and the processing in 5140 is performed, and then Then, the following processing is performed. After executing 5140, in synchronization with the original clock signal from the clock circuit 22 that reflects the rotational state of the gravure cylinder 2, driving waveform data is read from the reference start address BO and cell data is read from the gradation information storage unit 40. The gradation data is read point-sequentially (3190), and based on these data, an engraving signal for actually driving and controlling the engraving blade 4 in the cutting direction toward the surface of the gravure cylinder 2 is synthesized. is output to the engraving blade drive circuit 24 (S200). When synthesizing the engraving signal, the cutting depth of the engraving blade 4 is adjusted to the cell level by correcting the drive waveform data f1 to fN with the cell gradation data. Change according to the key data. Next, it is determined whether or not the engraving of the gravure cell spanning the scanning line has been completed, based on the processing result of a cell engraving completion routine (not shown) (the set state of a flag indicating completion of engraving) and the engraving on the surface of the gravure cylinder 2. Judgment is made based on the pressing count of the blade 4, etc. (S205), and data reading in synchronization with the clock original signal and synthesis and output of the engraving signal are repeated until it is judged that the engraving of the gravure cell spanning the scanning line is completed. . Therefore, the engraving blade drive circuit 24 includes the gravure cylinder 2.
The engraving signal is inputted point-sequentially reflecting the rotational state of the turret, so the engraving knife drive circuit 24 that receives this amplifies the signal and outputs the control signal to the actuator built in the tool rest 6. The engraving blade 4 is driven in the cutting direction toward the surface of the gravure cylinder 2 along the locus of a triangular wave (reference drive waveform) as shown by the solid line in FIG. 9 and FIG. 1O (a). As a result, gravure cells are engraved on the surface of the gravure cylinder 2 at the engraving pitch P. The driving locus (driving waveform) of the engraving blade 4 when the original image has a uniform color tone (reference color tone) is shown by a solid line in FIG. 10(a). Note that when the cell gradation data changes in response to changes in the color tone of the original image, these drive waveforms move in parallel to the cutting depth direction by the amount of the cell gradation data. When it is determined in step 5205 that the engraving of the gravure cell spanning the scanning line is completed, it is determined whether the value of the scanning line counter CN is 3 or less (S215). In the first processing, as described above, the value of the scanning line counter CN is 0, so an affirmative determination is made in 5215 and the value of the scanning line counter CN is incremented by 1 (S22
0). Then, after setting the value of the scanning line counter CN to 1 through this process, a turret movement signal for moving the turret 6 by P15 along the sub-scanning direction of the gravure cylinder 2 is output to the engraving head drive circuit 26. (S240) The processing of this routine is temporarily ended. As a result, the engraving head drive circuit 26 outputs a drive signal obtained by amplifying this turret movement signal to the sub-shaft motor 16,
The tool rest 6 is moved by P15 along the sub-scanning direction. In the subsequent processing of this routine, since the value of the scanning line counter CN is set to 1 at 5220, an affirmative determination is made at 5115. The scanning line for engraving the gravure cell this time is ((i-1)X5+2) from the end of the gravure cylinder.
=2, reference start address B
As shown in FIG. 9, 1 is an address that is shifted from the previous reference start address BO by the number of addresses corresponding to 2P15 cycles (S150). After the reference start address B1 is set in 5150, the process moves to 5190 and the following processes in S200 (dot sequential reading of signal data synchronized with the original clock signal, synthesis and output of engraving signals, completion of engraving of gravure cells) Judgment, incrementing the value of the scanning line counter CN (setting the value of CN to 2), and outputting the turret movement signal) are executed in sequence, and the processing of this routine is temporarily terminated. Through this series of processing, the end of the gravure cylinder ((i-1)X5+2) = In the two-port scanning line, the reference start address address B is shifted from the previous reference start address address BO by the number of addresses corresponding to 2P15 cycles.
The engraving signal is synthesized and output from l. As a result, the drive locus of the engraving blade 4 becomes a locus based on a drive waveform with a 2P15 period deviation from the reference drive waveform, as shown in FIG. 10(b), and the engraving pitch P is A periodic gravure cell is engraved with a scanning line direction phase difference of 2P15 from the previous gravure cell. Similarly, in the subsequent processing of this routine, if the scanning line counter CN=2, steps 5125 and 5160 are executed,
In the case of CN=3, 5135.5170, and CN
If =4, 3180 is executed. As a result, 3~
In the fifth grain scanning line, reference start addresses B2. B3. B4 is set respectively. And 5190, 5200, 520
5, a gravure cell is engraved on each scan line. Note that when CN=4 and the processes 5180, 5190 to 5215 are executed, a negative determination is made at 8215 and the process moves to 5230, where the value O is set to the scanning line counter CN and the value of i is incremented. Do 524
Execute process 0. When the engraving of the gravure cell is completed for five consecutive scanning lines, the above-mentioned process will be repeated, so the drive locus of the engraving blade 4 in the next process will be as shown in Fig. 10 (
As shown in f), it corresponds to FIG. 10(a). As explained above, the gravure cell engraving device 1 of this embodiment
The gravure cells are engraved over a certain scanning line at a period of the engraving pitch P, and then over the adjacent scanning line separated by P15 from this scanning line, the gravure cells are engraved at a period of the engraving pitch P and the scanning line direction of the gravure cells is A new gravure cell is engraved with a phase difference of 2P15, and this process is repeated. As a result, on the surface of the gravure cylinder 2, as shown in FIG. The intervals between the four gravure cells (the gravure cells on two adjacent scanning lines and the gravure cells on two double-exposed scanning lines) can be distributed at equal distances, that is, in the same direction. As a result, printed matter using such a gravure cylinder has an ink adhesion pattern with a screen angle having a rational tangent and an isodirectional arrangement pattern.
Images can be expressed with equal resolution in the main scanning direction and the sub-scanning direction, and uniform color tones similar to normal offset printing can be expressed. Furthermore, by appropriately selecting P and m, it is possible to engrave gravure cells with various periods and angles, so it is possible to find a combination that can suppress the occurrence of moiré and changes in color tone in printed matter. In addition, when holding the engraving knife 4, the bisector of the cutting surface angle of the engraving knife is maintained so as to pass through the central axis O of the gravure cylinder, and the rake face is tanθ= with respect to the scanning line of the gravure cylinder. Since the angle satisfies 1/2, the engraved gravure cell is made into a parallelogram with one opposite side parallel to straight line a, as shown by the solid line in Fig. 3 (A), and its edge is The part was formed to be a straight line. As a result, it is possible to maintain the isotropy of the constriction part, and as shown in FIG. It can be avoided that one side of the cell first coincides with the side of an adjacent cell. In this way, the depth and area of the gravure cell can be expanded compared to the case where the rake face is not tilted (FIG. 3 (B)), so the image can be reproduced to a higher density on the printed matter, It becomes possible to enrich the expression of tone shading (color tone expression). Also,
Smoothly contacts and slides the doctor blade against the surface of the gravure cylinder when applying ink to improve the cutting of ink from the edge and equalize the degree of ink remaining in each gravure cell with the same engraving depth and area. Therefore, the color tone can be made uniform. In addition, when engraving the gravure cell, please refer to Figure 11 (A
), as shown in (B), the gravure cylinder 2 (
The cutting direction drive control of the engraving blade toward the surface of the developed view (Fig. 11 (B)) and the sub-scanning direction drive control of the tool post (
If the steps in Fig. 11 (A)) are carried out at the same time and the engraving blade is driven along the locus shown by the dotted line in the figure, not only will the edge remain in a straight line as shown in the figure, but also the gravure The shape of the cell can be made closer to a square. At this time, according to this embodiment, it is possible to simply hold the engraving knife with its rake face tilted (this makes it possible to simplify the control and configuration. Above, one embodiment of the present invention has been described. However, the present invention is not limited to such embodiments in any way, and it goes without saying that it can be implemented in various ways without departing from the gist of the present invention.For example, as shown in FIG. , P −m/ (m' 2 1)(
The engraving control unit 20 is equipped with a triangular wave generating circuit group 50 having first to fifth triangular wave generating circuits 51 to 55 that generate a triangular wave at an engraving pitch P whose phase is shifted by 2P15) if m is 2. Clock circuit 22 and each triangular wave generating circuit 5 to input a clock signal to each triangular wave generating circuit
1 to 55, and each open/close switch 51a to 51 is interposed between each triangular wave generation circuit and the engraving head drive circuit 26.
5a, an output port 35 of the electronic control device 3o is connected to selectively control opening and closing of each of these switches. Then, each time the engraving of the gravure cell across the scanning line is completed, each opening/closing switch 51a to 55a is sequentially opened and closed.
The individual triangular waves generated by the first to fifth triangular wave generating circuits 51 to 55 may be output to the engraving head drive circuit 26. With this configuration, the amount of calculation required to configure the drive waveform signal is reduced, and the processing can be performed at higher speed. It is also possible to configure the tool rest 6 to move continuously in the sub-scanning direction at a speed of P15 while the gravure cylinder 2 rotates once. In this case, the engraving tool drive control shown in FIG. The process at 5240 in the routine is omitted, and the tool rest 6 is moved in the sub-scanning direction by P/(m'2+1
) may be provided separately from the engraving blade drive control routine. (Effect 1 of the invention As detailed above, according to the present invention, first, a predetermined pitch P along the surface of the gravure cylinder over one scanning line is provided.
Gravure cells are engraved on the surface of the gravure cylinder at intervals of P/(m"2+1) along the sub-scanning direction from this scanning line.
) across adjacent new running lines shifted by a distance of
The scanning line direction phase difference between gravure cells in mutually adjacent scanning lines is P-m/(m-2+1) or P・
(1-m/ (m" 2+ 1)) to engrave gravure cells at a predetermined pitch P, and repeat this process, so that each gravure cell on the surface of the gravure cylinder is are distributed at the intersection of two straight lines that are orthogonal to each other, and a certain gravure cell and its four nearest gravure cells (gravure cells on two adjacent scanning lines and gravure cells on two m-fold scanning lines) As a result, if such a gravure cylinder is used, the mesh pattern (ink adhesion pattern) on the printed matter can be distributed at a screen angle that has a rational tangent. Since the pattern is formed and isohistorical, it is possible to equalize the resolution in the main scanning direction and the sub-scanning direction, and it is possible to reproduce an image with uniform color tone. ) Since gravure cells are formed in the same pattern with a predetermined pitch P for each scanning line of the wood grain, and a square pattern with a pitch P appears on the gravure cylinder surface, the gravure cells can be formed equally with a cell pitch of P/(m'2+1). If you perform multicolor printing by using a gravure cylinder in which gravure cells are engraved with a historically arranged basic square cell pattern or a gravure cylinder in which m is a different integer value, it is possible to print a pattern that is an enlarged square pattern with a pitch P. The appearance of moire can be avoided, and the occurrence of moiré and changes in color tone in printed matter can be suppressed. Further, the engraving knife is held on the tool rest by maintaining the bisector of the cutting edge angle of the engraving knife along the scanning line of the gravure cylinder and tilting its rake face at a predetermined angle with respect to the scanning line of the gravure cylinder. According to the present invention configured as follows,
Since the gravure cell is made into a parallelogram with diagonal lines along the scanning line, the edge portion on the gravure cylinder surface can be formed so that the degree of zigzag is reduced along the above two straight lines that are orthogonal to each other. can. Therefore, when the ink is deposited, the contact and sliding of the doctor blade against the surface of the gravure cylinder is made smoother, and the cutting of the ink from the edge portion is improved, thereby making it possible to reproduce an even tone. Furthermore, the degree of ink remaining in each gravure cell having the same engraving depth and area is made uniform.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the basic configuration according to the second invention, No. 21! ! l and Figure 3(A). (B) is an explanatory diagram for explaining the effects of the present invention, FIG. 4 is a block diagram showing the schematic configuration of the gravure cell engraving device of this embodiment, FIG. 5 is a schematic perspective view of the engraving blade 4, and FIG. 6
7 and 7 are explanatory diagrams for explaining the holding state of the engraving knife 4, FIG. 8 is a flowchart of the engraving knife drive control routine, and FIGS. 9 and 10rgJ explain the processing contents in the engraving knife drive control routine. 11(A) and 11(B) are explanatory diagrams used to compare the effects of this embodiment, and FIG. 12 is a block diagram showing the schematic configuration of a gravure cell engraving device in another embodiment. Figure, 1st
FIG. 3 is a schematic FIA diagram for explaining the technology related to conventional gravure cell engraving. 2... Gravure cylinder 4... Engraving knife 6...
・Turret 10...Engraving section 20...Engraving control section 30...Electronic control unit 40...Gradation information storage section C1-C4...Gravure cell agent Patent attorney Igarashi Isolated

Claims (1)

[Claims] 1. An engraving knife for gravure cell engraving is pressed against the surface of a cylindrical gravure cylinder rotating around a central axis, and each of a plurality of scanning lines along the rotational direction of the gravure cylinder is formed. In the gravure cell engraving method of sequentially engraving the gravure cells at a predetermined pitch P, each time the gravure cylinder rotates, the engraving blade moves along the sub-scanning direction parallel to the central axis of the gravure cylinder P/(m ^2+1) (m is an integer greater than or equal to 2, and the operator ^ represents a power) while moving the engraving knife over one scanning line of the plurality of scanning lines. Gravure cells are engraved by pressing against the surface of a gravure cylinder at a predetermined pitch P, and the scanning line direction phase difference between the gravure cells in adjacent scanning lines is determined as P・m/(m^2+1) or P・(1−m). /(
m^2+1)), and with the set phase difference, press the engraving blade against the surface of the gravure cylinder at a predetermined pitch P across a new scanning line adjacent to the scanning line where the engraving of the gravure cell has been completed. A gravure cell engraving method characterized by: 2. An engraving knife for gravure cell engraving held on a tool rest that faces the surface of a cylindrical gravure cylinder that rotates around the central axis and is movable along the sub-scanning direction parallel to the central axis of the cylinder. and an engraving control means for sequentially engraving gravure cells on each of a plurality of scanning lines along the rotational direction of the gravure cylinder by driving and controlling the engraving blade in the incision direction toward the surface and in the sub-scanning direction, respectively. In the gravure cell engraving device, the engraving control means includes: a detection unit that detects the rotational state of the rotating gravure cylinder; a blade movement control unit that controls movement by a distance of P/(m^2+1) (m is an integer of 2 or more, and the operator ^ represents a power) along a sub-scanning direction parallel to the central axis of the cylinder; and the engraving. a control signal output unit that outputs a control signal for pressing a blade against the surface of the gravure cylinder at a cutting period of a predetermined pitch P based on a detection result of the detection unit; an incision direction drive control unit that drives the engraving blade against the surface of the gravure cylinder at intervals of the predetermined pitch P over one scanning line to engrave the gravure cells; Let the phase difference be P-m/(m^2+1) or P・(1-m/
(m^2+1)); and a phase difference setting section that sets the output timing of the control signal by the control signal output section after one rotation of the gravure cylinder to the set phase difference and the gravure cylinder detected by the detection section. A gravure cell engraving device comprising: an output timing changing section that changes the output timing based on the rotational state of the gravure cell engraving device. 3. The engraving knife has two cutting teeth that intersect at a predetermined cutting angle at its tip, and the tool rest that holds the engraving knife aligns the bisector of the cutting edge angle with the central axis of the gravure cylinder or The engraving blade is held so as to pass through the vicinity thereof, and the rake face surrounded by the two cutting teeth is tilted at a predetermined angle with respect to the scanning line with the bisector as the center. The gravure cell engraving device according to claim 2.