JP2009137758A - Paper sheet detection device of sheet-fed press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet detection device of a sheet-fed press allowing prevention of entering of an abnormally conveyed paper sheet in the printer by early detecting the abnormal conveyance, facilitating of a take-out work of the paper sheet, the reduction of the number of parts, simplification of a control method and reduction of cost, with hardly generating a failure of the printer. <P>SOLUTION: A feeder board 1 of a paper feeding part A is provided with detection devices 11 and 12 having transmitters 11a and 12a and receivers 11b and 12b. Each of the detection devices 11 and 12 is capable of detecting a superposed state of the sheet P, detecting a conveyance state in a bending direction of paper sheet P by detection timing and detecting also the conveyance state in the superposed direction of the paper sheet P. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet detection device for detecting an abnormality of a sheet when a sheet enters the apparatus in a sheet printing machine.

  In a sheet-fed printing machine, a bending detection device is provided that detects bending in the left-right direction with respect to the sheet conveyance direction when the sheet is conveyed from the sheet feeding unit into the apparatus. Patent Document 1 discloses this bending detection device, and the first detection sensor 17 and the second detection sensor 18 corresponding to the bending detection device are in the vicinity of the front plate 2 of the difference plate 1, that is, in the vicinity of the entrance in the printing press. Are provided at a plurality of locations.

  In addition, the sheet-fed printing press is also provided with a device called a superposition detection device. Sheets transported from the paper feeder into the machine are transported in a stacked state like tiles to be laid, and are fed one by one by swinging pawls to the machine, but if the transport condition is not good, This is detected because there is a possibility that the paper sheets are transported into the apparatus in a state where they overlap. This superposition detection device is also provided in the vicinity of the front of the difference plate, that is, in the vicinity of the entrance in the printing press. (See Patent Document 2)

JP-A-7-290694 JP 2007-204173 A

  As described above, the sheet detection device of such a conventional sheet-fed printing machine is provided near the entrance in the printing machine, and therefore, after the abnormality is detected, conveyance of the sheet by the sheet feeding unit is stopped. However, there are many cases where the sheet enters into the machine, and it may take time to take out the abnormally conveyed sheet or damage the parts in the machine.

  The present invention has been made in view of the above-described conventional problems, detects abnormal conveyance of a sheet at an early stage, prevents entry of the abnormally conveyed sheet into the machine, facilitates the operation of taking out the sheet, It is an object of the present invention to provide a sheet detection device for a sheet-fed printing machine in which machine failure is unlikely to occur.

  In order to solve the above-described problems, the present invention provides a paper feeding unit A and a feeder board that is provided in the paper feeding unit A and transports a sheet P that is transported in a state of being shifted by a predetermined amount in the transport direction and overlapping. 1 and a printing unit 20a to 20d for introducing and printing the sheet P conveyed on the feeder board 1 therein, the feeder on the feeder board 1 and the feeder A plurality of detectors 11 and 12 provided at a predetermined distance from the connection point of the board 1 with the printing units 20a to 20d to the upstream side in the transport direction and provided side by side in a direction orthogonal to the transport direction; The detectors 11 and 12 detect a left and right bent state with respect to the transport direction of the sheet P, and the detectors 11 and 12 also detect an overlap state of the sheets P. .

  According to the printing machine of the first aspect of the present invention, the detector is provided at a predetermined distance from the connection point with the printing unit of the feeder board to the upstream side in the transport direction, and the detector is a sheet of paper. Since the detector detects the left and right bending state with respect to the transport direction of the sheet, and also detects the overlapping state of the sheets, it can determine whether the sheet transport is normal or abnormal before the sheet enters the machine. Thus, the sheet that has been abnormally conveyed can be reliably prevented from entering the machine, the sheet can be taken out easily, and machine failure is unlikely to occur.

  A sheet-fed printing press according to an embodiment of the present invention will be described with reference to FIGS. As shown in the schematic overall view of FIG. 1, the printing machine according to the present embodiment is a sheet-fed offset printing machine, and includes a paper feeding unit A, printing units 20 a to 20 d, and a paper discharge unit 2. In each of the printing units 20a to 20d, an ink roller group, a plate cylinder 3, a rubber cylinder 4, and an impression cylinder 5 (not shown) are provided. A transfer cylinder 7 is provided between the impression cylinders 5. The impression cylinder 5 and the transfer cylinder 7 are provided with grippers (not shown), and the sheet P is conveyed between the impression cylinder 5 and the transfer cylinder 7 with the leading end held by the gripper. Reference numeral 6 denotes a paper feed cylinder that transfers the sheet P conveyed from the feeder board 1 of the paper feed unit A to the impression cylinder 5. The above-mentioned gripper is also provided in the sheet feeding cylinder 6. The sheets P stacked on the sheet feeding unit A proceed on the feeder board 1 in the direction of arrow Z and are conveyed to the printing unit 20a. Reference numeral M denotes a motor for driving the printing press.

  FIG. 2 shows a partial plan view of the feeder board 1. The sheet P is conveyed on the feeder board 1 in the direction of arrow Z, positioned after contacting the front pad 8, and then conveyed into the printing press (printing unit 20a) by a swing gripper (not shown). At a position spaced apart from the front end of the feeder board 1 by a predetermined distance (about 100 mm in this embodiment), the detectors 11 and 12 are in the sheet width direction, that is, the direction orthogonal to the sheet conveyance direction. It is attached.

  3 and 4 are partial side views of the feeder board 1. The detectors 11 and 12 are composed of transmitters 11a and 12a and receivers 11b and 12b, and the transmitters 11a and 12a are attached to the openings provided in the feeder board 1 from the back side of the feeder board 1. ing. The detectors 11 and 12 transmit ultrasonic waves from the transmitters 11a and 12a to the sheet P in the direction of the arrow Y, and whether there is an air layer between the sheets P by the ultrasonic waves received by the receivers 11b and 12b. And an ultrasonic sensor capable of detecting whether the sheet P is one or two (overlapping). FIG. 3 shows a state in which the detectors 11 and 12 are detecting one sheet P. Since the sheets P are transported in a state of being overlapped like tiles to be laid, after a predetermined time has elapsed from the state of FIG. 3, the detectors 11 and 12 detect two sheets of sheet P as shown in FIG. It becomes a state. When the leading sheet P is gripped by a swing gripper (not shown) that reciprocates at high speed from the two sheet detection state and conveyed into the apparatus, the state shown in FIG. 3 is obtained again. In the present embodiment, the two-sheet detection state shown in FIG. 4 is achieved when the rotation angle of a machine emitted from an encoder (not shown) attached to the paper feed cylinder 6 is 150 to 200 degrees. Since the detectors 11 and 12 each independently detect one or two sheets of the sheet P, the state of the sheet P in the bending direction can be determined by the difference in the detection timing (or detection time). ing. That is, when the detector 11 changes from the state where one sheet P is detected to the state where two sheets are detected, the detector 12 also changes from the state of detecting one sheet to the state of detecting two sheets at almost the same timing. For example, the conveyance state of the sheet P in the bending direction is normal. On the other hand, after the detector 11 detects two sheets, when the detector 12 detects two sheets at a considerably late timing, the conveyance state of the sheet P in the bending direction is abnormal as shown by a two-dot chain line in FIG. This must be an error. Further, as shown in FIG. 5, when the second and third sheets P are transported in a substantially overlapped state (abnormally overlapped state), even if the rotation angle of the machine exceeds 200 degrees. Two sheets are detected, and this needs to be an error.

  The operation of the present embodiment will be described based on the flowchart of FIG. First, in step S101, it is confirmed whether one of the detectors 11 and 12 detects two sheets P at a predetermined mechanical rotation angle (150 degrees ± 10 degrees in this embodiment). If NO in step S101, the driving mechanism (not shown) of the feeder board 1 is stopped as an abnormal conveyance state to prevent the sheet P from entering the apparatus (step S104). In the case of YES in step S101, it is confirmed whether either one of the detectors 11 and 12 has detected two at a predetermined timing (within 15 degrees from one detection) (step S102). In the case of NO in step S102, for example, as shown by a two-dot chain line in FIG. 2, the driving state (not shown) of the feeder board 1 is stopped by assuming that the conveyance state of the sheet P in the bending direction is abnormal, and the sheet P Intrusion into the aircraft is prevented (step S104). In the case of YES in step S102, it is confirmed whether or not both detectors are detected within a predetermined timing (200 degrees ± 10 degrees in the present embodiment) (step S103). If YES in step S103, the overlapping state of the sheets P is assumed to be normal, and the step ends. In the case of NO in step S103, for example, as shown in FIG. 5, it is assumed that the overlapping state of the sheets P is abnormal, and the driving mechanism (not shown) of the feeder board 1 is stopped to prevent the sheet P from entering the machine ( Step S104). Since the detectors 11 and 12 are located at a predetermined distance from the front end of the feeder board 1 (about 100 mm in this embodiment), the state of conveyance of the sheet P is determined before the sheet P enters the apparatus. It is possible to determine whether the sheet is normal or abnormal, and it is possible to reliably prevent the sheet transported abnormally from entering the machine, thereby making it easy to take out the sheet and preventing machine failure. In addition, when the overlap detection device that has only performed the function of confirming the overlap state of the sheets P can check the conveyance state of the sheet P in the bending direction, the printing apparatus omits the bend detection device. It is possible to reduce the number of parts, simplify the control method, and reduce the cost.

  The mechanism of the sheet detection device of the sheet printing machine according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. In the above-described embodiment, the detectors 11 and 12 are ultrasonic sensors. However, the sheet P is irradiated due to the difference in the amount of transmitted light that is emitted from the light emitter to the sheet P and received by the light receiver. A known sensor such as a photoelectric sensor that can detect the overlapping state of the two can be employed. In the above-described embodiment, the offset type sheet-fed printing press is used. However, a screen printing machine or a flexographic printing press may be used as long as the printing machine uses a sheet.

  The sheet detection device for a sheet-fed printing machine according to the present invention is extremely useful in a sheet-fed printing press having a detection device for detecting the conveyance state of a sheet.

1 is a side view of a sheet-fed offset printing press equipped with a sheet detection device according to the present invention. The partial top view which shows a feeder board and a detector. The feeder board and the partial side view of a detector which show the state where the detector detected one sheet. The feeder board and the partial side view of a detector which show the state which the detector detected two sheets of sheets. The partial side view of a feeder board and a detector which shows the state in which the overlapping state of a sheet is abnormal. The flowchart which shows the flow of a process of the sheet detection function of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Feeder board 11 Detector 11a Transmitter 11b Receiver 12 Detector 12a Transmitter 12b Receiver P Sheet paper

Claims (1)

  A sheet feeding unit, a feeder board that is provided in the sheet feeding unit and conveys sheets that are conveyed while being shifted by a predetermined amount in the conveying direction, and the sheet that has been conveyed on the feeder board. In a sheet-fed printing press having a printing unit to be introduced and printed therein, provided on the feeder board at a predetermined distance from the connection point with the printing unit of the feeder board to the upstream side in the transport direction. A plurality of detectors provided side by side in a direction orthogonal to the transport direction, the detector detects a left / right bending state of the sheet with respect to the transport direction, and the detector is the sheet A sheet detection device for a sheet-fed printing machine, characterized by detecting an overlap state of sheets.

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