JP3133120B2 - Speed difference detection method and speed difference detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed difference detecting method and a speed difference detecting device, and can be used for detecting a speed difference between two moving bodies such as a plate cylinder of a printing press which are to move at the same speed.

[0002]

2. Description of the Related Art Conventionally, in an apparatus having two moving bodies moving at the same speed, it is necessary to perform the same speed inspection, that is, to detect a speed difference at the time of installation or regular maintenance and inspection. For example, in an offset rotary printing press, it is necessary to detect a difference in rotational speed between a plate cylinder and a blanket cylinder, which should originally rotate at the same speed, in order to know the cause of a defect such as a single color double.

In order to inspect the rotational speed of the plate cylinder and the blanket cylinder at the same speed, a method of detecting each moving speed by an encoder or the like and calculating a relative speed by a differential circuit or the like is used. The same speed inspection is also applied to slip detection between a roll and an iron plate when rolling an iron plate.

[0004] On the other hand, in order to improve the same speed accuracy, the applicant of the present invention has proposed a method of measuring each surface speed to be moved at the same speed by using a laser beam and calculating a difference in moving speed. In FIG. 7, for example, a plate cylinder 91 and a blanket cylinder 92 of an offset rotary printing press 90 are driven to rotate at the same speed via a gear mechanism 93. The surface speed of each cylinder 91, 92 depends on the gear mechanism.
Due to the backlash of 93, etc., the speed is not always exactly the same, and a printing shift or the like occurs due to the difference in rotational speed.

Such a plate cylinder 91 and a blanket cylinder 92
In order to perform the same speed inspection, laser heads 94A and 94B are installed facing each body 91 and 92, respectively, and laser light 95
A, 95B, and reflected light 96A scattered on each surface
Receives 96B. The original laser beams 95A, 95B are processed by the processing devices 97A, 97B corresponding to the respective laser heads 94A, 94B.
And the reflected light 96A, 96B are compared individually, and each body 91,
Based on the Doppler effect due to the surface 92, the frequency shift occurring in the reflected light 96A, 96B is arithmetically processed to calculate the surface speed of each body 91, 92, and further the difference in speed between the differential device 98 and the display device 99 is calculated. The same speed inspection is performed by calculating or displaying.

According to the same-speed inspection based on the laser Doppler velocity measurement, much higher inspection accuracy can be obtained as compared with the conventional encoder system, and since the incorporation is unnecessary, the mechanical complexity of the target device is increased. Avoid. Further, since the device can be freely attached and detached, there is an advantage that the same device can be used for another part.

[0007]

However, in the same-speed inspection by laser Doppler velocity measurement described above, two systems of laser Doppler velocimeters or processing devices are required, and differential systems for comparing the speed measured in each system are required. Circuits are also needed.

Therefore, the structure becomes complicated, and
There is a problem that the installation work for the inspection becomes complicated and that the cost is unavoidable. Further, the laser head needs to be arranged facing the moving surface to be inspected, but in a narrow portion such as a plate cylinder and a blanket cylinder of an offset rotary press, two laser heads can be arranged in a desired state. There is a problem that is difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plate cylinder and a blanket of a printing press.
An object of the present invention is to provide a speed difference detecting method and a speed difference detecting device which have a simple structure and can be easily handled for installation and the like when calculating a rotational speed difference from a cut cylinder .

[0010]

SUMMARY OF THE INVENTION The method of the present invention is directed to a printing press.
A speed difference between the plate cylinder and the blanket cylinder to be moved at the same speed at the same speed, wherein a predetermined wavelength λ
And frequency fo of the laser light is incident at the plate cylinder surface on the plate cylinder <br/> incidence angle A given from predetermined side with respect to the moving direction of the reflected light from said plate cylinder by the incident light The above
The same angle of incidence on the surface of the blanket cylinder from the side opposite to the entrance side of the plate cylinder with respect to the direction of movement of the blanket cylinder.
A, and the plate cylinder and the blanket are obtained from the frequency f2 of the reflected light from the blanket cylinder due to the incident light.
The apparatus according to the present invention, which calculates a speed difference Vd of the cylinder Vd = λ (fo-f2) / sinA, is a plate for moving at the same speed in a printing press.
A speed difference detecting device for detecting a rotation speed difference between a cylinder and a blanket cylinder , wherein one light-emitting unit that emits a laser beam onto the surface of the plate cylinder and light reflected from the surface of the blanket cylinder are received. One light receiving unit, and a calculating unit that calculates the speed difference between the plate cylinder and the blanket cylinder from the frequency of the laser light emitted by the light emitting unit and the frequency of the reflected light received by the light receiving unit, light projecting portion and a light receiving portion is incident at a predetermined incident angle from a predetermined side laser beam with respect to the moving direction of the plate cylinder to the surface of the plate cylinder from the light projecting unit, the plate according to the incident light The reflected light from the trunk is the blanket
On the surface of the cylinder with respect to the direction of movement of the blanket cylinder.
The light is incident at the same angle from the side opposite to the incident side of the plate cylinder , and the light reflected from the blanket cylinder due to the incident light is arranged to enter the light projecting portion.

[0011]

[Operation] In the present invention, a plate of laser light is used.
Due to the two reflections on the cylinder and the blanket cylinder , each velocity difference appears as a frequency change in the final reflected light due to the Doppler effect. For example, the frequency of light incident on the plate cylinder in the traveling direction decreases, and the frequency of light incident on the blanket cylinder in the direction opposite to the traveling direction increases. Here, if the surface speeds of the plate cylinder and the blanket cylinder are equal, the increase and decrease of the frequency at each become equal, and the reflected light finally obtained remains at the same frequency as the original laser light. However, if there is a difference between the respective surface velocities, the difference between the increase and decrease of the frequency due to each will appear.

That is, when the original laser beam is reflected by the plate cylinder, it undergoes a frequency change fd1 = V1 sinA / λ due to the Doppler effect corresponding to the surface speed V1 of the plate cylinder , and the original laser beam has a frequency fo relative to the original laser beam frequency fo. The frequency of the reflected light is f1 = fo−fd1.
Here, the wavelength of the reflected light from the plate cylinder is λ1 = C / f1 = C / (fo-fd1) = C / (C / λ−f, while the wavelength of the original laser light is λ = C / fo.
d1) = 1 / (1 / λ−fd1 / C). Where C is the speed of light.

[0013] Then, the reflected light from the plate cylinder is subjected to frequency change fd2 = V2sinA / λ1 by the Doppler effect in accordance with the surface speed V2 of the blanket cylinder when the reflected blanket cylinder <br/>. However, since the direction of incidence of the laser beam on the plate cylinder and the direction of incidence of the reflected light on the blanket cylinder are opposite to the respective moving directions, the sign of the change is reversed, and the final reflected light Is f2 = f1 + fd2. here,
The wavelength λ1 of the reflected light incident on the blanket cylinder = 1 / (1 / λ
−fd1 / C), the frequency change fd at the blanket cylinder
2 = V2sinA / λ1 = V2sinA / (1 / (1 / λ-fd1 / C)) = V2s
inA (1 / λ−fd1 / C). At this time, since fd1 is sufficiently smaller than C, fd1 / C can be ignored, and the frequency change fd2 = V2
sinA / λ.

By these two reflections, the frequency of the finally obtained reflected light becomes f2 = f1 + fd2 = fo− (fd1−fd2), and the frequency change fd = fod = fod (fd1−fd2).
fd1−fd2 is generated. Here, the frequency change fd = fd1−fd2
= V1sinA / λ−V2sinA / λ = (V1−V2) sinA / λ.
Therefore, the surface speed V1 of the plate cylinder and the surface speed of the blanket cylinder
Assuming that the speed difference from V2 is Vd = V1-V2, this speed difference Vd = fdλ
/ sinA, and the speed difference Vd can be calculated based on the frequency change fd appearing in the final reflected light.

Therefore, in the present invention, by arranging one optical path so as to be reflected on the plate cylinder and the blanket cylinder halfway, the projection of the laser beam and the reception of the final reflected light are performed one by one. As a result, mechanical simplification can be realized, and at the same time, reduction in mechanical cost, ease of handling, and the like can be realized, thereby achieving the above object.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a plate cylinder of an offset rotary printing press 10 is shown.
11 and blanket cylinder 12 have radii R1 and R2 (R1 = R
2) and rotate at the same speed but in the opposite direction at the same speed in a state where they are in contact with each other. However, due to various causes, the respective surface velocities V1 and V2 are not always equal, and the velocity difference Vd =
(V1-V2) may occur.

In order to detect such a speed difference Vd between the plate cylinder 11 and the blanket cylinder 12, a speed difference detecting device 20 using a laser Doppler type speed meter is provided.
That is, a laser head 30 is arranged on a common tangent line T between the plate cylinder 11 and the blanket cylinder 12, and the laser head 30 detects a frequency tracker 21 for detecting a frequency from an output signal thereof, and detects a fluctuation of the detected frequency. Flutter analyzer 2
2. A display device 23 for displaying the detected frequency and its fluctuation is connected.

As shown in FIG. 2, the laser head 30 includes a laser light source 31 as a light emitting section and a light receiving element 32 as a light receiving section. The laser light source 31 is a semiconductor laser element or He-
It is a Ne laser element or the like, and generates a laser beam having a wavelength λ of about 780 to 630 nm by power from a dedicated laser power supply 33. The light receiving element 32 receives light from outside through a lens 34, converts the intensity of the light into an electric signal,
And output to the outside through the main amplifier 36. Power is supplied to the preamplifier 35 and the main amplifier 36 from a DC power supply 37.

Here, the laser light 41 from the laser light source 31
Is applied to a predetermined portion P1 on the surface of the rotating plate cylinder 11.
At this time, the light is incident obliquely from the rear side of the surface of the plate cylinder 11 in the moving direction, that is, from the direction along the moving direction, and the incident angle is set to the angle A with respect to the surface normal, that is, the radial direction of the plate cylinder 11 ing. The laser light 41 is scattered and reflected on the surface of the plate cylinder 11, and the main reflected light 42 is directed to the blanket cylinder 12 at an emission angle A.

Further, the reflected light 42 from the plate cylinder 11 irradiates a predetermined portion P2 on the surface of the rotating blanket cylinder 12.
At this time, the incidence is performed obliquely from the front side in the moving direction of the surface of the blanket cylinder 12, that is, from the side opposite to the moving direction, and the incident angle is set to the angle A with respect to the normal line of the surface, that is, the radial direction of the blanket cylinder 12. . The reflected light 42 is scattered and reflected on the surface of the blanket cylinder 12, and the main reflected light 43
Is directed toward the lens 34 or the light receiving element 32 at the emission angle A.

In order to set the incident angle and the outgoing angle of each of the light beams 41 to 43 to the angle A, the positions and directions of the laser light source 31 and the lens 34 or the light receiving element 32 are appropriately set. Here, if the radii R1 and R2 are equal, the site P on each surface
1 and P2 may be symmetrical with respect to the common tangent T between the plate cylinder 11 and the blanket cylinder 12, and the optical paths of the light beams 41 to 43 may be adjusted so that the reflected light 42 is orthogonal to the common tangent T2. For example, each torso
A surface portion on a radius line intersecting at a point Q on the common tangent line T among the radii 11 and 12 may be selected.

In this embodiment, the laser light
41 is sequentially reflected by the plate cylinder 11 and the blanket cylinder 12, and the surface velocity difference between the cylinders 11, 12 is detected by measuring the Doppler effect according to each surface velocity. First, the laser light source 31
Is applied to the surface portion P1 of the plate cylinder 11. The irradiated laser light 41 has a wavelength λ and a frequency fo = C / λ, but receives a frequency change fd1 = V1sinA / λ due to the Doppler effect according to the surface speed V1 of the plate cylinder 11 at the time of reflection, and the reflected light 42
Has a frequency of f1 = fo−fd1, and a wavelength of λ1 = 1 / (1 / λ−fd1 /
C).

Next, the surface light P2 of the blanket cylinder 12 is irradiated with the reflected light 42. The irradiated reflected light 42 has a frequency f1 = fo
−fd1 and wavelength λ1 = 1 / (1 / λ−fd1 / C), but the frequency change due to the Doppler effect according to the surface speed V2 of the blanket cylinder 12 during reflection fd2 = V2sinA / λ1 = V2sinA / λ
And the frequency of the reflected light 43 is f2 = f1 + fd2 = fo− (fd1−
fd2), and the frequency change fd = fd1−fd2 occurs with respect to the original frequency fo of the laser light 41. This frequency change is fd = fd1−fd2 = V1sinA / λ−V2sinA / λ = (V1-V
2) sinA / λ, and the speed difference between the surface speed V1 of the plate cylinder 11 and the surface speed V2 of the blanket cylinder 12 is Vd = V1-V2 = fdλ / sinA
It is.

Subsequently, the reflected light 43 from the blanket cylinder 12
Is received by the light receiving element 32, the frequency is detected by the frequency tracker 21, the change of the frequency is detected by the flutter analyzer 22,
The frequency detected by the display device 23 and its change are displayed. That is, the frequency change between the frequency fo of the laser light 41 generated by the laser light source 31 and the reflected light 43 received by the light receiving element 32.
fd is measured, the wavelength λ of the laser beam 41 and the set incident angle
By calculating based on A, the surface speed of the plate cylinder 11 can be calculated.
Speed difference Vd between V1 and surface speed V2 of blanket cylinder 12 Vd = V1-V
2 = fdλ / sinA is obtained.

According to the present embodiment, the laser light 41
The speed difference Vd between the plate cylinder 11 and the blanket cylinder 12 can be detected through one optical path of the reflected light 42 to the reflected light 43. For this reason, a laser head that emits and receives laser light
30 and the frequency tracker 21 or the display device 23 for processing and calculating the output signal can be provided by one system, and the device configuration required for speed difference detection can be simplified.

Further, since the configuration of the apparatus including the laser head 30 is simplified, the cost required for these apparatuses can be reduced. In addition, since the device configuration can be simplified, the work can be performed quickly and efficiently even in the case of attaching and detaching for inspection.

Further, since only one laser head 30 needs to be installed, it can be easily installed even in a narrow place such as the periphery of the plate cylinder 11 and the blanket cylinder 12 of the offset rotary printing press 30, and the speed of various parts can be increased. It can be widely applied to difference detection.

It should be noted that the present invention is not limited to the above-described embodiment, and for example, the following modifications are included in the present invention. That is, in the above embodiment, the plate cylinder 11
And the blanket cylinder 12 have the same radius R1, R2, the points P1, P on the radius passing through the point Q on each common tangent T
FIG. 3 shows the case where the laser beam was reflected on the plate 2 and the radius R2 of the double cylinder, ie, the blanket cylinder 12, is twice the radius R1 of the plate cylinder 11.
It is desirable to adopt the following points Q, P1, and P2.

In FIG. 3, a triangle having the vertices of points Q, P1, and P2 is a vertex angle of points P1 and P2 in order to make incident angle A equal.
A is an isosceles triangle because A must be equal,
The lengths L of the two sides sandwiching the point Q must be equal. Here, the distances from the centers O1 and O2 of the plate cylinder 11 and the blanket cylinder 12 to the point Q are R1 + L and R2 + L, respectively. Here, assuming that the common tangent T is the x-axis and the axis passing through the contact To and orthogonal to the common tangent T is the y-axis, the contact To is the origin O, and the area where the point Q can exist is on the circumference of the radius R1 + L from the center O1. And a portion on the circumference of the radius R2 + L from the center O2. In other words, the point Q (x, y) is met ^{x 2 + (y-R1)} 2 = (R1 + L) 2,
And ^{x 2 + (y + R2)} 2 = (R2 + L) 2 x from clogging the radius R2 = 2R1
² + (y + 2R1) ² = (2R1 + L) ² is satisfied. Therefore, in the case of the double body as shown in FIG. 3, (y + R1 / 2) ² / (R1 / 2) ² −x ² / 2R1 ² = 1
In the hyperbola, the point Q is set on the line passing through the contact point To, and the optical path may be set so as to reflect the surface portion on the radial line from the centers O1 and O2 passing through the point Q2.

On the other hand, in the above embodiment, the detection of the speed difference between the plate cylinder 11 and the blanket cylinder 12 of the offset rotary printing press 10 rotating at the same speed in the opposite direction has been described. You may apply to a moving part etc. At this time, it is desirable to appropriately set the optical path so that the incident angles A to the moving parts are equal and the incident directions are opposite to each other with respect to the surface moving directions.

For example, in the case of performing the same speed inspection of two rotating bodies rotating at the same speed and the same speed in the same direction, as shown in FIG. Light is incident at an incident angle A from the rear side in the surface moving direction, and the reflected light 55 is once reflected by a reflecting mirror 56 to form a light beam 57 incident at the same incident angle A from the front side in the surface moving direction of the other rotating body 52, and the reflection The light 58 may be received by the light receiving unit 59. At this time, it is desirable to appropriately adjust the position of incidence on the rotating bodies 51 and 52 and the position and orientation of the reflecting mirror 56, and finely set the incident angles A to be equal.

In the case where a sheet fed linearly and a roll rolling on it are inspected at the same speed, as shown in FIG. From the side at an angle of incidence A, and the reflected light 65
What is necessary is just to make the light incident at the same incident angle A from the front side in the surface movement direction of 62, and to receive the reflected light 66 by the light receiving section 67. In such a case, the setting can be easily performed by setting the incident portion to the roll 61 on a radius line parallel to the sheet 62 and setting the incident angle A to 45 °.

Further, as shown in FIG. 6, the laser beam 74 from the light projecting section 73 is applied after the surface movement direction of one of the sheets 71, for example, when the two sheets fed in a straight line are inspected at the same speed. The reflected light 75 may be incident at the same incident angle A from the front side in the surface movement direction of the other sheet 72, and the reflected light 76 may be received by the light receiving unit 77. In such a case, since the sheets 71 and 72 are linear, the optical path can be set geometrically.

On the other hand, the configuration of the apparatus for performing the laser Doppler type velocity measurement is not limited to the one described in the above embodiment, but may be any one capable of projecting and receiving a laser beam in a desired state. The unit in which the unit and the light receiving unit are integrated, a separate unit, a light emitting unit, a frequency analyzing unit, and the like may be appropriately selected for implementation.

[0035]

As described above, according to the present invention,
It is possible to detect a speed difference between the plate cylinder and the blanket cylinder by the laser light by sequentially reflected on the plate cylinder and the blanket cylinder of a printing press to compare the frequency change due to the Doppler effect in each device required for measurement Can be simplified and handling such as installation can be facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a main part of the embodiment.

FIG. 3 is a schematic view showing a modification of the present invention.

FIG. 4 is a schematic view showing a modification of the present invention.

FIG. 5 is a schematic view showing a modification of the present invention.

FIG. 6 is a schematic view showing a modification of the present invention.

FIG. 7 is a schematic configuration diagram showing a conventional example.

Claims (2)

(57) [Claims] 1. A speed difference detecting method for detecting a speed difference between a plate cylinder and a blanket cylinder to be moved at the same speed in a printing press, the method comprising: detecting a laser beam having a predetermined wavelength λ and a frequency fo. is incident at a predetermined incident angle a from a predetermined side on the surface of the plate cylinder to the moving direction of the plate cylinder, the blanket reflected light from the plate cylinder by the incident light on the surface of the blanket cylinder
The incident side in the plate cylinder to the moving direction of the cylinder is incident at the same incident angle A from the opposite side, the bra according to the incident light
From the frequency f2 of the reflected light from the neck cylinder , the plate cylinder and
A speed difference detection method comprising calculating a speed difference Vd = λ (fo-f2) / sinA of a blanket cylinder . 2. A speed difference detecting device for detecting a rotational speed difference between a plate cylinder and a blanket cylinder to be moved at the same speed in a printing press , wherein a laser beam is projected on a surface of the plate cylinder. One light emitting part
One light receiving unit that receives the reflected light from the surface of the blanket cylinder , and the plate cylinder and the frequency of the laser light emitted by the light emitting unit and the frequency of the reflected light received by the light receiving unit and
And a calculator for calculating a speed difference between the blanket cylinder, the light projecting section and a light receiving unit, the laser light from the light projecting unit is predetermined with respect to the moving direction of the plate cylinder to the surface of the plate cylinder From the side at a predetermined incident angle, and the incident light
The Bed light reflected from the plate cylinder to the surface of the blanket cylinder
With respect to the moving direction of the racket cylinder , light enters from the opposite side to the incident side of the plate cylinder at the same incident angle, and the incident light causes
A speed difference detecting device, wherein a reflected light from a blanket cylinder is arranged so as to be incident on the light projecting portion.