JPH0144514Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting curvature of paper that is fed from a paper feeder onto a differential plate and fed to a printing cylinder by a swing device in a sheet-fed printing press.

The structure and operation of the paper feeding device and printing device of a sheet-fed printing press will be explained based on the schematic side view of the printing press in which the present invention is implemented as shown in FIG. It is equipped with a paper stacking table 4 that automatically and dynamically rises as the paper 3 is loaded and the amount of paper 3 decreases as it is fed out. is provided. The printing device 5 also includes a plate cylinder 6 on which a printing plate is mounted on the circumference, a blanket cylinder 7 to which an image formed on the plate is transferred, and a paper 3 that passes between the blanket cylinder 7. An impression cylinder 8 that applies printing pressure to the cylinders 7 and 8 and a transfer cylinder 10 that transfers the printed paper 3 between the cylinders 7 and 8 to the impression cylinder 9 of the next printing unit are provided with their peripheral surfaces facing each other. ing. Paper feeding device 2 configured in this way
Front and rear rollers 11, 1 are provided between the printer 5 and the printer 5.
A plurality of paper feed tapes 13 stretched in parallel between the two and a flat plate-shaped difference plate 14 are continuously arranged, and between the tip of the difference plate 14 and the impression cylinder 8. A swing device 15 is provided which has a gripping claw that opens and closes using a cam mechanism and swings at a predetermined period.

In the printing machine configured in this way, the paper 3 that has been sucked by the suction device and moved forward is moved by the upper and lower paper feed rollers 1 provided in front of the paper feed tape 13.
When the end of the paper is inserted between the paper ends 6 and 17, it is caught and sent out, conveyed by the paper feed tape 13, and fed onto the difference plate 14. A front cover 18 is provided near the tip of the difference plate 14, and the front cover 18 is raised or lowered by a cam mechanism.
The edge of the paper is gripped by the claw of the swing device 15 that swings as the front cover 18 falls and approaches.
Then, the paper 3 held in the nail is moved to the swing device 1
At the swing end position of 5, it is gripped by the claw of the impression cylinder 8, and as the impression cylinder rotates, it is sent between the blanket cylinder 7 and the impression cylinder 8, and the first color printing is performed.

In the paper feeding and printing operations performed in this way, the paper may not be properly stacked due to failure of the suction device, braking of the paper due to static electricity, poor paper stacking, etc.
If one end of the paper in the width direction advances or lags behind the other end, so-called paper bending occurs, and if printing continues while this occurs, the registration accuracy may be disrupted and correct printing may not be performed, or the swing device 15 may
A device for detecting paper bending is provided at the tip of the difference plate 14 to prevent the paper from being poorly held in the mouth.

A conventional detection device of this type has a pair of left and right photoelectric elements at the tip of the difference plate 14, which detects the bending of the paper 3 and controls the paper feeding operation of the paper feeding device 2 and the front plate 1.
8 is stopped, the swing device 15 is swung with the claws open, and the two barrels 7 and 8 are removed, and the detection accuracy is usually 0.3 to 1.0. It is set to mm. This detection device is used not to maintain the above-mentioned registration accuracy, but rather to prevent paper from falling due to poor gripping of the swing device 15, or by feeding bent paper into the gap between the two cylinders 7 and 8. This is provided to prevent damage to the blanket 3, and for this reason, as mentioned above, the claws of the swing device 15 open at the same time as a fraudulent paper is detected to prevent the paper 3 from being caught in the mouth.

However, conventional detection devices operate correctly if the paper bends up to about 15 mm, but if the paper bends more than this, one end of the paper 3 that has moved forward will fall into the open claw of the swing device. Even if the claws are open, the stiffness of the paper means that it will be carried as it is and try to be inserted between the two bodies 7 and 8. On the other hand, the center part and the other end of the paper 3 are
Since the brake is applied by the front stopper 18 which is stopped in the upright state, the paper 3 is torn as a result, and the torn and overlapping paper is rolled up between the two cylinders 7 and 8.

In this way, the paper 3 is rolled up without using the detection device, and the blanket of the blanket cylinder 7 is dented and damaged.
Not only is a large amount of time and materials wasted trying to balance the water, but excessive force is applied to the paper guide member around the front, which requires re-adjustment, resulting in a large amount of troubleshooting work. Therefore, at present, one worker is stationed at the paper feeding section to monitor the paper feeding section whenever the paper feeding condition is not good.

The present invention was developed in view of the above points, and a pair of left and right reflective floodlights is installed above the paper guide plate immediately after the paper feed roller that captures the front end of the paper sucked by the suction device and sends it out. The irradiated light is reflected and received by a reflective member on the lower surface of the transparent body embedded in the paper guide plate, and the bending of the paper on the paper guide plate is detected by the change in the amount of light.
To provide a paper bend detection device for a sheet-fed printing press that can detect paper bends at an early stage and stop greatly bent paper before a front plate. Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 4 show an embodiment of the paper bend detection device according to the present invention, FIG. 1 is a schematic side view of a sheet-fed printing press in which this is implemented, and FIG. 2 is a side cross-section of the paper bend detection device. 3 and 3 are front views, and FIG. 4 is a plan view of the paper guide plate. Since the structure of the entire printing press was previously explained based on FIG. 1, explanation thereof will be omitted except for the relevant parts. In the figure, a lower paper feed roller 17 is rotationally driven and supported on the left and right paper feed frames 19, and above it, a plurality of narrow paper feed rollers 16 are mounted on an arm (not shown). The paper feed roller 17 is supported by and pressed against the paper feed roller 17. A stay 20 is supported between the left and right frames 19 between the paper feed roller 17 and the roller 11 at the starting end where the paper feed tape 13 is stretched, and a pair of left and right collars fixed to the stay 20 21, both ends of a paper guide plate 22 are fixed. This paper guide plate 22 is
It is formed into a long plate shape that almost connects the upper ends of the circumferential surfaces of 7 and 11, and the upper surface is plated in black. Furthermore, a pair of left and right arms 23 are fixed to both ends of the stay 20, and are integrally formed with a split-shaped boss 23a and a strip-shaped support member 23b that projects obliquely upward from the boss 23a. A corner stay 24 is supported between them. Reference numeral 25 denotes a pair of holders fitted to the corner stay 24, and the paper 3 can be removed by loosening the bolt 26.
It is formed to be movable and adjustable according to the size of the body, and is fixed at the adjusted position by tightening the bolt 26.

Each holder 25 is provided with a reflective projector 2 configured to irradiate light, reflect it off a reflector, and detect the properties of the reflector based on the amount of reflected light.
7 is mounted with the light emitting direction directed toward the tip of the paper guide plate 22, and this projector 27 is provided with a volume for adjusting sensitivity. In addition, paper guide board 2
A pair of left and right transparent plates 28 made of acrylic resin and formed into a rod shape are embedded in the tip of the paper 2, and the positions thereof are the light receiving positions from the respective projectors 27 and the width direction of the paper 3. It is set to extend from slightly inside the edge _L1 of the smallest sheet of paper to slightly outside of the edge of the largest sheet of paper shown in FIG. Furthermore, a reflective tape 29 is attached to the lower surface of the transparent plate 28, which is formed into a larger tape shape and reflects the light from the projector 27. Furthermore, the light projector 27 is connected to a control device (not shown) by a lead wire, and the paper feed operation of the paper feed device 2 and the rotation of the front cover 18 are controlled via the control device by a signal emitted by detecting the reflected light. The opening/closing operation of the claws of the swing device 15 is stopped, and the printing device 5 is removed. In addition, in the vicinity of the front cover 18, the above-mentioned detection device having an output used similarly to the detection output by the light projector 27 is provided as in the past.

The operation of the paper bend detection device configured as above will be explained. Prior to printing work, the holder 25 is moved according to the size of the paper 3, and each floodlight 27 is
Adjustments are made so that a portion of the paper 3 passing over the paper guide plate 22 is irradiated approximately 15 mm laterally from both side edges thereof. Then, when the printing operation starts, the paper is sucked up one by one by the suction device of the paper feeder 2, and the front end is captured by the upper and lower paper feed rollers 16, 17, and sent onto the paper guide plate 22, and then the paper is sent out onto the paper guide plate 22. It is conveyed by the feed tape 13 and sent onto the differential plate 14. The paper 3 that has come into contact with the front cover 18 that stands up at the tip of the difference plate 14 is held by the claws of the swing device 15 and conveyed, and then transferred to the claws of the impression cylinder 8 and moved between it and the blanket cylinder 7. Printing is done with .

In such printing work, paper bending occurs due to various causes in the paper feeding device 2 as described above, and the paper is caught by the paper feed rollers 16 and 17 with either the left or right edge leading. The paper is fed onto the paper guide plate 22. Here, the floodlight 2
Light is emitted from 7 toward the transparent plate 28, and this light passes through the transparent plate 28 and is reflected by the reflective tape 29.
and is reflected back to the projector 27. When a bent piece of paper 3 is fed in with one front edge ahead of the other, the trailing edge of the paper on the side where the front edge is ahead is pushed out further than normal and reflects light. The light from the shielded light projector 27 is reflected by the paper 3. In general, the reflectance of white paper is about 83%, and the reflectance of the reflective tape 29 is 90% or more even when it passes through the transparent plate 28, so the projector 27 emits signals with different outputs depending on this difference. This signal causes the paper feeding operation of the paper feeding device 2 and the paper feeding operation of the paper feeding device 2 and the
The rotation of the swing device 15 and the opening/closing operation of the claws of the swing device 15 are stopped, and the printing device 5 is removed. Furthermore, this crooked paper continues to be fed after being detected, but generally the paper 3 is moved by the paper feed roller 16
From when it is captured by 17 to when it hits front stop 18,
Since there is a margin of about 4 rotations of the printing cylinder, in this device in which the detection section is provided immediately after the paper feed rollers 16 and 17, the paper 3 hits the front cover 18 when the paper feed tape 13 stops after detection. It stops before the end and does not go over the front stopper 18. Note that this device only detects greatly bent paper that has gone too far by 15 mm or more at the position of the front cover 18, and paper that is extremely slightly bent can be straightened by a metal tool called a rake installed at the front cover. A paper with a slightly larger bend than this will be detected by a conventional detection device installed in the front part and stopped, so that it will not be caught by the claws of the swing device. Generally, a paper tensioning device called a cross needle is provided on the side of the difference plate 14, and the paper 3 may be stacked with a widthwise shift of about 5 mm in consideration of the tension.
Also, depending on paper stacking accuracy and paper feeding accuracy, paper 3 may shift within ±5 mm in the width direction, but this degree of shift is outside the detection range of this device, so this normal shift cannot be detected. There is no possibility of malfunction due to detection.

As is clear from the above explanation, according to the present invention, in the paper bending detection device of a sheet-fed printing press, the front end of the paper sucked by the suction device is caught and sent out. A pair of reflective floodlights is installed, and the light emitted by these is reflected by a reflective member on the lower surface of the transparent body embedded in the paper guide plate and received, and the bending of the paper on the paper guide plate is detected by the change in the amount of light. With this configuration, paper bending is detected early and stopped before the paper comes into contact with the front cover, and there is no risk of the paper being caught in the swing device and fed to the printing cylinder, which prevents the paper from tearing and printing. It does not wrap around the cylinder, which prevents damage to the blanket of the rubber cylinder, and also eliminates the need for maintenance and adjustment of parts and ink/water balance adjustment that are associated with accidents, which greatly saves time and materials. The effect is extremely large. In addition, the reliability of the device is high and there is no need to deploy special workers to monitor paper bending.
Labor saving can be measured. Furthermore, by making the projector movable and adjustable and lengthening the transparent body and reflective member, it is possible to handle papers of all sizes.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the paper bending detection device for a sheet-fed printing press according to the present invention, FIG. 1 is a schematic side view of a sheet-fed printing press in which this is implemented, and FIG. FIG. 3 is a side sectional view of the detection device, FIG. 3 is a front view, and FIG. 4 is a plan view of the paper guide plate. 1... Printing machine, 3... Paper, 16, 17... Paper feed roller, 22... Paper guide plate, 27... Light projector,
28...Transparent plate, 29...Reflective tape.

Claims (1)

[Scope of utility model registration request] Immediately above the paper feed rollers 16 and 17 that catch the front end of the paper sucked by the suction device and feed it out, light is projected toward the paper guide plate 22 that slides the fed paper, and changes in the amount of reflection are detected. A pair of left and right reflective projectors 27 are provided to stop the paper feeding operation, and the projector 27 on the paper guide plate 22 is provided.
A transparent body 28 having a reflecting member 29 attached to the lower surface thereof is embedded in the light receiving position of the paper, and the light emitting position of the light projector 27 is located at a part laterally away from both edges of the paper. Paper bend detection device for sheet-fed printing presses.