JPH0444366Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an improvement of an incorrect paper feeding detection device for an offset sheet-fed printing press.

[Conventional technology]

In Fig. 6, 1 is a paper feed section, 2 is a first color printing unit, 3 is a second color printing unit, 4 is a paper discharge section, 5 is a pile, 6 is paper, 7 is an endless tape, 8 is a front cover plate, 9 is a front pawl, 10 is a swing gripper, 11 is a first intermediate cylinder, 12 is an impression cylinder, 13 is a rubber cylinder, 14 is a second intermediate cylinder, 15 is an impression cylinder, and 16 is a rubber cylinder.

Generally, in offset sheet-fed printing, sheets 6 are taken out one by one from the top of a pile 5 in a paper feed section 1 as shown in FIG. 6, and placed on an endless tape 7 in front of a registration section. It is fed so as to stop at a front abutment claw 9 provided at the end of the abutment plate 8.
The front end of the paper 6 is gripped by a swing gripper 10, pulled out, and delivered to a first intermediate cylinder 11 of the printing section. Thereafter, the printing paper passes along the path shown by the arrow, and the first color is printed between the impression cylinder 12 and the blanket cylinder 13 of the first color printing unit 2, passes through the second intermediate cylinder 14, and is transferred to the impression cylinder 15 of the second color printing unit 3. The second color printing is performed between the blanket cylinders 16 and the paper is discharged via the paper discharge section 4.

To explain the main parts in more detail in Fig. 7,
The entire device that speeds up the paper 6 fed from the paper feed section 1 at a fixed position and then speeds it up to the circumferential speed of the first intermediate cylinder 11 is called a register section. A front pawl 9 is provided for setting the sheet in position, and a swing gripper 10 is provided for speeding up the paper to the first intermediate cylinder circumferential speed and delivering it thereto. When the paper 6 is set in a certain position by the front pawl 9, the swing gripper 10 comes to pick up the paper 6 and grips the edge of the paper 6. Then, the front pawl 9 moves to the left on the rotation locus 17 and retreats. Next, the swing gripper 10 grips the paper 6 and rotates on the rotation locus 18 to the point of contact with the first intermediate cylinder 11. Trajectory 18
passes outside the locus 17, and as shown in the plan view of the end of the front abutment plate in FIG. The paper 6 can be transferred from the claw to the swing gripper 10 without any problem. Note that 9' is a notch for the front abutment claw provided at the end of the front abutment plate 08, and 10' is a notch for the swing gripper.

(a) Register detector This is a device that detects the direction in which paper is traveling. It is installed near the front register and determines the presence or absence of paper. If there is no paper in the specified position, it immediately issues a command to stop printing.

(b) Two-sheet detector This is a detector that confirms that there is only one sheet of paper, and immediately issues a command to stop printing when two or more sheets of paper are sent.

(c) Overflow detector Activates when the paper flows faster than a predetermined phase or passes over the front claw and issues a command to stop printing.

(d) Horizontal staple detector This is a device that detects paper in either direction in the horizontal direction.It is installed near the horizontal staple and detects the presence or absence of paper.

FIG. 5 shows a conventional embodiment of a front stopper claw 9, a swing gripper 10, and various detectors at the end of the front stop plate near the front stop.

[Problem that the invention attempts to solve]

In the conventional arrangement of various types of detectors, notches 019' and 019' are provided at the inner side of both ends of the paper width at the end of the front abutment plate 08 of the paper feeding front abutment section immediately before the swing gripper, and one set of register detectors 19 is arranged. 2 detectors 20
1 by making a notch 020' in the part corresponding to the center line of the paper width.
It was customary to provide one set of over-travel detectors 21 with a notch 021' provided on one side of the detector 21 which is located away from the center line of the paper width.

With this conventional arrangement, if the paper is fed in a twisted state as shown by the two-dot chain line (lower side of Figure 5), the cause may be poor pile, poor separator paper feed accuracy,
Timing imbalance of the gripping roller, uneven pressure of the gripping roller, tack between sheets, poor smoothness of the front plate, etc.) From the viewpoint of the operation, 2 sheets can be detected if 1 is on the center line of the paper width.
Because of this, it is impossible to detect the twisted state, so the two sheets proceed to the printing section, causing printing and functional problems. Furthermore, in terms of performance, the fraud detection rate is low, and due to the arrangement of the detectors, the overflow detectors are biased toward the center line of the paper width and are unbalanced.

[Means for solving problems]

In the conventional arrangement of various types of detectors, two-sheet detectors are installed at the locations where register detectors are installed at the portions corresponding to both ends of the paper width, and overshoot detectors are installed at the portions corresponding to the center line of the paper width.

With this arrangement, in terms of operation and performance, even if a sheet of paper is fed in a twisted manner and hits the front claw, the two-sheet detector on either the left or right side will detect the two-sheet portion, and the probability of detection will be significantly increased. In addition, since the overshoot detector is placed on the center line of the paper width, the arrangement balance is improved.

〔Example〕

1 to 4, 6 is the paper, 8 is the front plate, 19 is the register detector, 19a is the register detector (light emitter), 19b is the register detector (light receiver), 20 is the 2
sheet detector, 20a is a 2 sheet detector (light projector), 20
b is a two-piece detector (light receiving part), 22 is a detector holder, 23 is a detector bracket, 24 is a glass plate,
25 is painted black.

The upper part of Figure 1 shows a plan view of one embodiment of the end portion of the front plate of the unauthorized paper feeding detection device according to the present invention, and the lower part of Figure 1 shows a plan view of an embodiment of the end portion of the front plate of the unauthorized paper feeding detection device according to the present invention, and the lower part of Figure 1 shows a plan view of the end portion of the front plate of the unauthorized paper feeding detection device according to the present invention. FIG.

In the device of the present invention, notches 19', 19' are provided at the end of the front abutment plate 8 corresponding to the inner side of both ends of the paper width in the paper feeding front part just before the swing gripper, and two sheet detectors and a registration detector are provided in the paper advancing direction. Two sets of paper detectors are arranged in one notch in the order of 19, a total of four sets at both ends,
Further, a notch 21' is provided at a portion corresponding to the center line of the paper width, and one set of overflow detectors 21 is provided.

As shown in Fig. 1, when two sheets of paper 6 come in twisted as shown by the two-dot chain line, the conventional system misses the timing by detecting two sheets of paper that are delayed by δ from the leading edge of the paper. Since there are two detectors 20, detection can be performed at the tip and there will be no failure.

Furthermore, since it is now possible to place the overshoot detector 21 on the center line of the paper width, the arrangement is well balanced and the detection reliability is improved.

Figures 2 and 3 show an example of integral mounting of a register detector and a two-sheet detector as an embodiment of the present invention. Figure 2 is a side view, and Figure 2 4 is a Y-Y line in Figure 2.
FIG. 3 shows a view taken along line XX in FIG. 2. The register detector 19 is a reflective type, and the two-sheet detector 20 is a reflective type.
shows a transmission type, and all of them are commercially known. The detector holder 22 is the register detector 19a, 1
9b and the two-sheet detector light emitting part 20a are integrally housed and mounted facing the notch 19' of the front contact plate 8, and a detection sensor is placed on top of this at a predetermined distance so that the paper 6 can freely pass through. The bracket 23 is installed,
This includes two detection light receiving sections 20b or protective glass 24.
It is covered and stored.

The inventor of the present invention applied anti-reflection black coating 25 to the entire lower surface of the protective glass plate 24, except for the vicinity of the two-sheet detection light-receiving section 20b, to prevent reflections when the paper 6 is not passing through and to improve the alignment. Detection 19a, 19
We have obtained good results by taking steps to prevent the occurrence of false detections.

[Effect of idea]

Since two-sheet detectors were installed, one set on the inside of both ends of the paper width, there was no longer a detection delay when the paper came in twisted. Also, since the over-travel detector is placed on the center line of the paper width, the placement balance has been improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the unauthorized paper feeding detection device of the present invention.
FIG. 2 is a side view of the register detector and two-sheet detector of the present invention, FIG. 3 is a view along the X-X arrow in FIG. 2, and FIG. 4 is a view along the Y-Y arrow in FIG. FIG. 5 is a plan view of a conventional paper feed detection device, FIG. 6 is an overall side view of a sheet-fed offset printing press, and FIG. 7 is a detailed side view of the front portion of the sheet-fed offset printing press.

Claims (1)

[Scope of utility model registration request] At the section in front of the paper feed just before the swing gripper,
A notch is provided at the end of the front cover plate corresponding to the inner side of both ends of the paper width, and two sets of paper detectors are installed in the notch in the order of two paper detectors and a register detector in the paper traveling direction, for a total of 4 at both ends.
What is claimed is: 1. An improper paper feeding detection device, characterized in that one set of overflow detectors is provided by providing a notch in a portion corresponding to the center line of the paper width.