JPH01125231A - Metallic plate offset press - Google Patents

Abstract

PURPOSE:To obtain a metallic plate offset press capable of accurate detection of misregistering for any metallic plate, by providing a pair of left and right optical sensors in an impression cylinder, and directly measuring the position of the leading end of a metallic plate fed between a blanket cylinder and the impression cylinder and gripped by the impression cylinder. CONSTITUTION:Two front gauge mechanisms 34a, 34b are provided at left and right positions slightly closer to a contact surface than the tips of grippers 32a-32n. Like a gripper holder 33, the front gauge mechanisms 34a, 34b are fixed to an opening and closing shaft 44, and are turned. Before a metallic plate is gripped by the grippers 32a-32b, the leading end thereof makes contact with the front gauge mechanisms 34a, 34b. Namely, when the leading end of the metallic plate is brought into contact with the front gauge mechanisms 34a, 34b and the shaft 44 is turned to the opening side, the mechanisms 34a, 34b are first separated from the leading end of the plate, and then the grippers 32a-32n release the plate. The position of the leading end of the metallic plate held stationary by the mechanisms 34a, 34b is detected by a pair of micro-sensors 36a, 36b provided at left and right symmetrical positions. Therefore, the angle of bend of the leading end of the metallic plate relative to the feeding direction can be detected from the difference between the values measured respectively by the sensors.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the detection of misregistration in a metal plate offset printing device.

[Prior art]

2. Description of the Related Art In paper offset printing apparatuses, sensors have conventionally been used to detect vertical/horizontal misregistration. The paper fed from the paper feed section is conveyed to the printing unit (between the blanket cylinder and the impression cylinder) via the delivery section, and is held in the impression cylinder. In order to determine the timing of this gripping, the feeding section has a front stopper, at which the conveyance of the paper is stopped once.

A sensor for detecting the position of the paper is provided near this front pad, and the stationary position of the paper when it hits the front pad is measured by the sensor. Then, depending on whether the paper is in a predetermined position or not, it can be predicted whether the top/bottom/left/right registration will match or deviate as a result of being conveyed to the printing unit and printed. If misregistration is predicted, printing is not performed.

However, in a metal plate offset printing device, the metal plates are sent out one by one from the paper feed section, and are sent out from the rear at the delivery section to the front by the backing mechanism, and hit the front end of the impression cylinder, at almost the same timing. Since it is configured to be held in the mouth with a claw, there is no front stopper on the delivery section. For this reason, since the metal plate is not in a stationary state immediately before being carried into the printing unit, misregistration cannot be predicted by the sensor before printing.

Therefore, workers visually inspect the product after printing. Here, since all products are inspected, the burden of inspection work is heavy, and there have been problems such as an increase in the price of printed matter due to the labor costs of the workers, and a long inspection time.

Therefore, in recent years, devices have been developed that automatically detect misregistration before printing in metal plate offset printing apparatuses. There is a misregistration detection device described in Japanese Utility Model Application Publication No. 59-110632. In this device, a measuring element supported by a spring is installed in the impression cylinder. When the metal plate is held in the mouth, its tip causes the measuring member to move backward against the spring force. Misregistration is predicted by detecting the rear end position of the measuring member at this time with a sensor head also provided within the impression cylinder.

[Problem that the invention seeks to solve]

This conventional example is based on using a sensor to indirectly measure the amount of movement of the measuring member, which is in a floating state due to a spring, by the metal plate. Therefore, errors in the displacement of the measuring member due to the moment of inertia of the rotating impression cylinder are avoided. Yes, the sensor readings were unreliable. Similarly,
The amount of displacement also changes due to mechanical deterioration such as deterioration of the fitting used for floating and deterioration of the spring, making it difficult to perform highly accurate and stable measurement over a wide range.

Furthermore, if the metal plate is unstable due to differences in plate thickness, measurements may not be possible.

Furthermore, if the position of the front plate is moved back and forth depending on the length of the metal plate, the measured value will change, so it is necessary to move the sensor position back and forth in the same way, or adjust the level of the measured value, which is time-consuming and time-consuming. It took a while.

This invention was made to deal with the above-mentioned circumstances,
It is an object of the present invention to provide a metal plate offset printing device that can always accurately detect misregistration of any metal plate.

Another object of the present invention is to provide a metal plate offset printing apparatus that does not require sensor position adjustment even if the position of the front cover changes.

[Means and effects for solving the problem] The metal plate offset printing apparatus according to the present invention includes a pair of left and right optical sensors in the impression cylinder, and the metal plate is conveyed between the blanket cylinder and the impression cylinder and is picked up by the impression cylinder. Misregistration is detected by directly determining the position n1 of the tip of the obtained metal plate, and depending on the detection result, printing of the metal plate is stopped or the metal plate is separately ejected.

Further, according to the metal plate offset printing apparatus according to the present invention, the optical sensor is provided integrally with the front cover mechanism, and includes a light emitting element embedded in the front cover member, and a light emitting element provided in the upper part of the front cover member and mounted in the mouth. By providing the light receiving element provided in the holder connected to the opening/closing shaft of the claw holder, the detection value of the light receiving element is not affected even if the position of the front cover is changed.

〔Example〕

Hereinafter, embodiments of a metal plate offset printing apparatus according to the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a printing unit for one color in the first embodiment. - Color printing units include a paper feed section (metal plate supply section) 10, a delivery section 12, a printing section 14, and a paper ejection section (metal plate ejection section)
It has 18. In multicolor printing, a plurality of printing units are provided in series, and the delivery section 12 of the printing unit of the next color is connected after the paper delivery section 1B. A motor 20 is provided to feed the metal plate and drive the printing section 14.

The printing section 14 includes an inking roller 22, a dampening roller 24,
It consists of a plate cylinder 2B, a blanket cylinder 28, and an impression cylinder 30. Ink is applied to the plate surface of the plate cylinder 26 by the inking roller 22. The ink on the printing plate is transferred to the rubber film 28a on the surface of the blanket cylinder 28. The impression cylinder 30 is in contact with the blanket cylinder 28. The metal plate is carried between the impression cylinder 30 and the blanket cylinder 28, and is pressed against the blanket cylinder 28 by the impression cylinder 30, whereby printing is performed.

The first embodiment is characterized in that in order to detect misregistration, a pair of optical sensors that can directly detect the misalignment of the metal plate are provided inside the impression cylinder 30 on the left and right sides. Next, the arrangement of this optical sensor will be explained.

FIG. 2 is a plan view of the impression cylinder 30. FIG. 3 is a side view of the impression cylinder 30 seen from the right side in FIG.

Figure 4 (a) + (b) + (C) are the a-a = line, bb- line, and c-c- in Figure 2, respectively.
FIG. 3 is a sectional view of the impression cylinder taken along the line. Pa and Pb in FIG. 2 are the metal plates when they are held in their mouths, and when they are conveyed normally, they are when they are conveyed crookedly, causing misregistration.

Inside the impression cylinder 30, in front of the contact surface between the impression cylinder 30 and the blanket cylinder 28 (double-dashed line in the figure), there are a plurality of gripping claws 32a to 32a.
32n are provided at equal intervals. In FIG. 2, only the gripping claws 32a and 32n on both sides are shown for simplicity.

A cross-sectional view of the gripping claw 32a is shown in FIG. 4(a). Claw 3
2a is provided in the gripping claw holder 33;
is fixed to the opening/closing shaft 44 and rotates as the opening/closing shaft 44 rotates. As a result, the gripping claw 32a moves up and down with respect to the impression cylinder 3°, and grips and releases the metal plate between it and the claw base 46 embedded in the impression cylinder 3o. The metal plate is held by the claws 32a to 3.
While being held between the blanket cylinder 2n and the blanket cylinder 46, the printing cylinder 30 passes between the impression cylinder 30 and the blanket cylinder 28 as the impression cylinder 30 rotates, and is printed. However, unlike a paper offset printing device, the metal plate is not held in the impression cylinder 30 so much as to wrap around it, but after passing between the impression cylinder 30 and the blanket cylinder 28, if the metal plate is rotated by an appropriate angle, The gripping claws 32a to 32n rotate upward to release the metal plate. Therefore, the metal plate is separated from the impression cylinder 30 and heads toward the paper discharge section 16.

Slightly on the contact surface side of the tips of the gripping claws 32a to 32n,
Two front support mechanisms 34a and 34b are provided on the left and right sides in the axial direction of the impression cylinder 30. It should be noted that the number of front support mechanisms is not limited to two, but may be more than two.

A sectional view of the front cover mechanism 34a is shown in FIG. 4(b).

The front cover mechanisms 34a and 34b are also fixed to the opening/closing shaft 44 in the same way as the gripping claw holder 33, and are rotated by the rotation of the opening/closing shaft 44. However, the phase angles of the front protection mechanisms 34a, 34b and the gripping claws 32a to 32n are different, and the tip of the metal plate comes into contact with the front protection mechanisms 34a, 34b before being gripped by the gripping claws 32a to 32n. It is supposed to be done. That is, the tips of the metal plates of the gripping claws 32a to 32n come into contact with the front support mechanisms 34a and 34b, and after the movement of the metal plate has stopped, they rotate downward and enter the gripping state.

When the opening/closing shaft 44 is rotated toward the opening side, first, the front stop mechanisms 34a and 34b move away from the tip of the metal plate, and then the gripping claws 32a to 32n open the metal plate.

The position of the tip of the metal plate held still by the front cover mechanisms 34a, 34b is detected by a pair of microsensors 38a, 3Bb provided at symmetrical positions in the axial direction of the impression cylinder 30.

A cross-sectional view of the microsensor 38a is shown in FIG. 4(C). The microsensors 36a and 38b are optical sensors that have a light emitting element and a light receiving element, and measure the amount of light that changes when it is blocked by the metal plate that is the object to be detected. It measures the position (displacement) of the tip. Furthermore, since the displacement is measured on both sides of the conveyance direction, the bending angle of the tip of the metal plate with respect to the conveyance direction can be detected from the difference between the constant values on both sides.

Here, the light emitting element 80 is embedded in the impression cylinder 30, and the light receiving element 82 is provided in the claw portion 8B of a light receiving element holder 84 having the same shape as the gripping claw holder 33. Photodetector holder 84
is also connected to the opening/closing shaft 44 and rotates at the same timing as the gripping claw holder 33, and the light receiving element 82 moves up and down with respect to the impression cylinder 30. The light receiving element 82 also receives the light beam from the light emitting element 80 at the same time that the metal plate is held in the holding claw.

Note that the timing of emitting the light beam from the light emitting element 80 is also linked to the rotation of the opening/closing shaft 44. Infrared rays are preferable as the light used for n1 constant. Normally, the limit for printing misregistration is 4/100 to 5/100 (+am), so the sensor accuracy (detection ability) is 2/100 to 3/100.
It is set to 100 (+ui). Therefore, the diameter φ of the light beam from the light emitting element 80 is set to 3 degrees.

Output current signals from the microsensors 38a and 38b pass through the impression cylinder 30 and are supplied to the control unit 42 via the rotary connector 40. The low reconnector 40 contains inorganic mercury. Although not shown, the rotational phase of the impression cylinder 30 is detected by an encoder.

As shown in FIG. 3, an eccentric metal 50 is incorporated into the shaft of the impression cylinder 30. Exen Metal 5
0 is connected to an air cylinder 54 via a link 52. Therefore, the pressure between the impression cylinder 30 and the blanket cylinder 28 is attached and detached by displacement of the air cylinder 54.

Figure 5 shows 1. (This is a circuit diagram of the J1 section 42. The output current signals of the microsensors (displacement sensors) 36a and 38b are input to the displacement sensor controller 56 and the current/current signal is input to the displacement sensor controller 56.
The voltage is converted and inputted to the control unit 42 as a voltage signal (DCO~2V). An output signal from an angle sensor (for example, a low angle encoder) 58 connected to the same rotation axis as the impression cylinder 3o or an integral multiple rotation axis is also input to the control unit 42. In addition, an upper and lower limit setting switch 6o1 is provided to set the limit of displacement to be detected as misregistration, and an angle sensor setting switch 62 is also provided to determine the timing of capturing the output signals of the displacement sensors 38a and 38b, and these outputs are controlled. 42.

Both setting switches 60 and 82 are digital switches.

The output voltage signal of the displacement sensor controller 5B is supplied to the display circuit 6B as an analog signal via the buffer 64, and is also supplied to the display circuit 66 as digital data via the A/D converter 68. The output of the A/D converter 68 is also input to a comparison circuit 70. The outputs of the angle sensor 58, the upper and lower limit setting switch 60, and the angle sensor setting switch 62 are supplied to a comparison circuit 70. The angle sensor setting switch 62 sets the detection phase angle during the period in which the gripping claws 32a to 32n grip the metal plate during one rotation of the impression cylinder 30.

When the output of the angle sensor 58 matches this angle, the comparison circuit 70 outputs the displacement sensor 38 which is the output of the A/D converter 68.
It is determined whether each of the output digital data of a and 38b is within the setting range of the upper and lower limit setting switch BO. As a result, it is possible to determine whether the metal plate has been conveyed to a predetermined position and whether the conveyance state is tilted, thereby making it possible to predict misregistration. Prior to detecting misregistration of each metal plate, the amount of light received by a metal plate that has been normally conveyed and is normally held in the impression cylinder is set as a reference value in the comparison circuit 70.

Although not shown, a sensor for detecting the passage of the metal plate is provided in the delivery section 12, and misregistration is detected only when there is an output from this sensor.

The comparison result of the comparison circuit 70 is supplied to the display circuit 66 and also to the output circuit 72. When misregistration is detected, the display circuit 6B displays the amount of misregistration as a voltage or position accuracy data on the meter 74.

The output circuit 72 is photocoupled, and processes such as buzzer energization, lamp lighting, barrel release, and paper discharge conveyor are performed by relay output and transistor output. The activation of the buzzer and lighting of the lamp are warnings of misplacement. Cylinder release means to instantly release the impression cylinder 30 from the blanket cylinder 28 by displacing the air cylinder 54 shown in FIG. Therefore, although the six cylinders of the printing section 14 are rotating, only the metal plate concerned is not printed. When the passage of the next metal plate is detected, the displacement of the air cylinder 54 is released and the impression cylinder 30 is brought into contact with the blanket cylinder 28 again. Paper discharge conveyor processing is an operation in which metal plates that have not been printed are separately discharged onto a vertically moving paper discharge conveyor to a paper discharge section different from normal printed matter by cylinder relief.

As described above, according to the first embodiment, misregistration is predicted by directly measuring the position of the tip of the held metal plate with an optical microsensor installed in the impression cylinder. Measured values do not change due to the moment of inertia of the cylinder or mechanical deterioration, allowing highly accurate and stable measurements over a wide range. Furthermore, even if the material or thickness of the metal plate changes, the measurement will not be affected.

Next, a second embodiment of the invention will be described. Here, the first
The same parts as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, optical sensors (microsensors) 36a, 36b are placed in front of mechanisms 34a, 34.
It is characterized by being integrated with b.

FIG. 6 is a plan view of the impression cylinder 30. Inside the impression cylinder 30, there is an impression cylinder 3 in front of the contact surface between the impression cylinder 30 and the blanket cylinder 28.
A plurality of gripping claws 32 arranged in the axial direction of 0 are provided at equal intervals. Here, for the sake of simplicity, four gripping claws 32 are used.
Only a to 32d are shown. A pair of front support mechanisms 34a and 34b are provided at symmetrical positions in the axial direction of the impression cylinder 30, slightly on the contact surface side of the tips of the gripping claws 32a to 32d, and the metal plates are attached to the gripping claws 32a to 32d. Before it is held in its mouth, its tip comes into contact with the front protection mechanisms 34a and 34b. That is, the gripping claws 32a to 3
2d, the tip of the metal plate comes into contact with the front support mechanisms 34a and 34b, and after the movement of the metal plate has stopped, the gripping operation is performed.

The front cover mechanisms 34a and 34b are configured to include microsensors. FIG. 7 shows the front support mechanism 34a and the gripping claw 3.
2a and 32b, FIG. 8 is a detailed plan view of the front cover mechanism 34a, FIG. 9 is a sectional view of the impression cylinder 30, FIG. 10 is a sectional view of the front cover mechanism 34a, and FIG. 11 is a detailed plan view of the front cover mechanism 34a. It is a perspective view of a front member.

As shown in FIG. 10, the front holder 10B is connected to the opening/closing shaft 44 similarly to the gripping claw holder, and is rotated by the rotation of the opening/closing shaft 44. As shown in FIG. 8, the front holder 1
08 holds the front member 10B so as to sandwich it from both sides. The front member 10B is fixed to the front member holder 108 by fixing screws 11B.

Therefore, when the screw 116 is removed, the front member 106 can be moved back and forth with respect to the holder 108. The front surface of the front cover member 10B becomes the contact surface with the metal plate.

A push spring 1 is provided between the front member 106 and the holder 108.
14 is provided, and when the screw LL8 is removed, the front member 106 is urged away from the holder 108. The front member 106 is moved back and forth by rotating the adjustment knob 102 having an eccentric shaft. A scale indicating the amount of movement of the front member 106 is provided on the circumference of the adjustment knob 102. Here, if the hole of the screw 11B is made larger by the adjustment margin of this adjustment knob 102, the front cover member 11 can be adjusted by simply loosening the screw 116 without removing it.
You can move 6 forward or backward.

As shown in FIGS. 10 and 11, a hole is formed in the front member 106 at an angle to the contact surface with the metal plate on the front side, and a light emitting element 110 is embedded in the hole.

As shown in FIG. 10, a light-receiving element holder 104 having a similar shape to the gripping claw holder is provided on the front member 10B, and a light-receiving element 100 is embedded in the tip thereof facing the light-emitting element 110. It will be done.

As a result, when the metal plate contacts the front member 10B,
Depending on the conveyance state, the degree to which light from the light emitting element 110 is blocked varies and the amount of light incident on the light receiving element 100 changes. displacement) can be measured.

The light receiving element holder 104 does not hold the metal plate in its mouth, but holds it down from above to prevent overrun.

Then, the metal plate of the light-receiving element holder 104 passes through the contact surface between the impression cylinder 30 and the blanket cylinder 28, and the gripping claws 32a--
32n rotates upward to release the metal plate, and at the same time, the holder 108 rotates upward, thereby similarly rotating upward and stopping pressing the metal plate from above. This prevents the metal plate from wrapping around the impression cylinder 30. Although not shown, the light receiving element holder I (1
4 may move back and forth instead of moving up and down and stop pressing the metal plate from above.

According to the second embodiment, by incorporating a microsensor that measures the tip position of the metal plate in the front cover function, even when the position of the front cover is moved back and forth, the position of the sensor,
Or you can work without having to adjust the level of the measured value.
Improves operational efficiency.

Note that this invention is not limited to the embodiments described above, and can be modified in various ways. For example, the operation when misregistration is detected is not limited to the above description. Furthermore, although a transmission type sensor has been described as an optical sensor, a reflection type sensor may also be used.

〔Effect of the invention〕

According to this invention, a pair of left and right optical sensors are provided in the impression cylinder, and the position of the tip of the metal plate conveyed between the blanket cylinder and the impression cylinder and held by the impression cylinder is directly measured. A metal plate offset printing device is provided that allows predictable deviations.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram of a first embodiment of a metal plate offset printing apparatus according to the present invention, Fig. 2 is a plan view of the impression cylinder, Fig. 3 is a side view of the impression cylinder, and Fig. 4(a). , (b), (c
) is a sectional view of the impression cylinder, Fig. 5 is a block diagram of the control section, and Fig. 6 is a sectional view of the impression cylinder.
The figure is a plan view of the impression cylinder of the second embodiment, FIG. 7 is a detailed plan view of the front support mechanism and gripping claw, FIG. 8 is a detailed plan view of the front support mechanism, and FIG. 9 is a detailed plan view of the impression cylinder. A side view, FIG. 10 is a sectional view of the front cover mechanism, and FIG. 11 is a perspective view of the front cover member. 10... Paper feeding section, 12... Feeding section, 14... Printing section, 1G... Paper discharge section, 26... Plate cylinder, 2B...
Blanket cylinder, 30... Impression cylinder, 32a-32n...
- Gripping claws, 34a, 34b...front mechanism, 38
a, 38b...optical sensor, 42...control unit. Applicant's agent Patent attorney Takehiko Suzue (a) Figure 4 Figure 7 Figure 11

Claims (4)

[Claims] (1) In a metal plate offset printing device that prints when a metal plate passes between a blanket cylinder in contact with a plate cylinder and an impression cylinder in contact with the blanket cylinder, a pair of left and right optical sensors are provided in the impression cylinder, and a pair of left and right optical sensors are provided in the impression cylinder; Misregistration is detected by optically measuring the position of the tip of the metal plate carried between the blanket cylinder and the impression cylinder and held by the impression cylinder, and depending on the detection result, the printing operation is stopped or the metal plate is A metal plate offset printing device characterized by separately ejecting the plate. (2) When a misregistration is detected, the impression cylinder is temporarily separated from the blanket cylinder, and the metal plate on which the misregistration is detected is not printed. Board offset printing equipment. (3) The optical sensor includes a light emitting element embedded in the impression cylinder and a light receiving element provided in the holder connected to the opening/closing shaft of the gripping claw holder. The metal plate offset printing device according to item 1. (4) The optical sensor is provided integrally with the front cover mechanism, and includes a light emitting element embedded in the front cover member, and a holder provided on the upper part of the front cover member and connected to the opening/closing shaft of the gripping claw holder. The metal plate offset printing apparatus according to claim 1, further comprising a light receiving element provided within the metal plate offset printing apparatus.