JP2007196688A - Loss paper sensor of printing sheet processing machine, especially sheet-fed printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To offer a new loss paper sensor of a sheet-fed printing machine. <P>SOLUTION: The invention refers to the loss paper sensor and is related to the loss paper sensor of a printing sheet processing machine, especially of the sheet-fed printing machine, and to the light beaming device (12) which directs the optical examination light beam (13) to the area of the printing sheet feeding passage which is to be scrutinized, to the euphotic apparatus (17) which, when there is no printing sheet paper existing in the area to be scrutinized as mentioned above of the above-mentioned printing sheet feeding passage, receives the examination light beam or the examination light beam (13) reflected in the reflecting device (14) as the reflective light beam (16). The examination light beam (13) and/or the reflective light beam (16), when there exists the printing sheet paper in the area to be scrutinized of the printing sheet feeding passage, collides against the surface of the printing sheet paper with the acute angle (α) of maximum of 5 degrees. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing sheet processing machine according to the preamble of claim 1, and more particularly to a damaged paper sensor of a sheet printing machine.

  In a printing sheet processing machine, for example, a sheet printing machine, the printing sheet is conveyed by a conveying device configured as, for example, a gripping system. When transported, the printed sheet may leave the transport device under various circumstances. The printing sheet processing machine must be stopped or stopped immediately, otherwise the processing machine may be severely damaged. A so-called broken paper sensor is used to check whether a printed sheet is present.

  In the case of printed sheets known from practice, a reflected light gate (Reflektionslichtschranken) is usually used as a damaged paper sensor. The reflected light gate includes a light transmitting device, a light receiving device, and a reflecting device. In this case, the light transmitting device directs the optical inspection light beam to an area to be monitored in the sheet transport path. This optical inspection light beam can be reflected as a reflected light beam by the reflection device, and can be received by the light receiving device as a reflected light beam. At that time, the inspection light beam transmitted from the light transmitting device reaches the region of the reflecting device only when the printed sheet does not exist in the region of the printed sheet conveyance path. Similarly, the inspection light beam reflected as the reflected light beam by the reflection device reaches the region of the light receiving device only when the printing sheet is not present in the region of the printing sheet conveyance path. Other broken paper sensors function without a reflector and utilize light reflected by the printed sheet.

  The above-mentioned function of the waste paper sensor known from practice is only reliably performed when printing sheets that are printed with transparent foil or UV printing ink are not used as printing sheets. Accordingly, there is a need for a broken paper sensor that can reliably detect broken paper even in the case of transparent printed sheets or printed sheets printed using UV printing ink.

  In view of the above, an object of the present invention is to provide a novel damaged paper sensor of a printing sheet processing machine.

  The above problem is solved by the waste paper sensor according to claim 1. According to the present invention, the inspection light beam and / or the reflected light beam forms an acute angle of a maximum of 5 degrees when the printing sheet is present in the area to be monitored of the printing sheet conveyance path. Collides with the paper surface.

  According to the present invention, the inspection light beam and / or the reflected light beam forms an acute angle of a maximum of 5 degrees when the printing sheet is present in the area to be monitored of the printing sheet conveyance path. Collide with the surface. In this case, if an acute angle of up to 5 degrees is maintained, the inspection or reflected light falling on the printed sheet surface is either completely absorbed, fully reflected or greatly attenuated, As a result, even in the case of a transparent printed sheet, it becomes possible to reliably detect the damaged paper.

  A printed sheet with an inspection beam and / or reflected beam forming an acute angle between 0.5 degrees and 3 degrees when the printed sheet is present in the area to be monitored of the printed sheet transport path. It is preferable to collide with the surface of the leaf paper.

  According to a preferred aspect of the present invention, the light receiving device reflects the inspection light beam reflected by the reflection device only when there is no printed sheet in the area to be monitored of the printed sheet conveyance path. As indirect or indirect light reception. For this purpose, at least one reflecting device is provided corresponding to a group of components for conveying sheets, in particular a rotating transfer cylinder. This reflection device is provided for the printed sheet transported in the printed sheet transport path. One or each reflector device directs the reflected light beam to the light transmitter device substantially along a path that the light transmitter device directs the inspection beam to the reflector device. The light transmitting device and the reflecting device are integrated into one component member.

  Preferred configurations of the invention emerge from the dependent claims and the following description. Examples of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these examples.

  FIG. 1 shows a first embodiment of a paper loss sensor 10 for a sheet printing machine according to the present invention, together with a group of components for conveying sheets of the sheet printing machine, which are configured as a rotating transfer cylinder 11. Is shown. The paper loss sensor 10 includes a light transmission device 12 that directs the inspection light beam 13 to an area to be monitored in the printing sheet conveyance path. In this case, the inspection light beam 13 is an optical inspection light beam. In the embodiment of FIG. 1, the waste paper sensor 10 further comprises at least one reflector 14. The light transmitting device 12 directs the inspection light beam 13 toward the reflection device 14, and the inspection light beam 13 is reflected only when the printing sheet 15 is not present in the area to be monitored in the printing sheet conveyance path. Collide with. The inspection light beam 13 that collides with the reflection device 14 is reflected by the reflection device 14 and directed to the light receiving device 17 as a reflection light beam 16. This reflected light beam 16 also reaches the region of the light receiving device 17 from the reflecting device 14 only when the printing sheet 15 does not exist in the printing sheet conveyance path.

  In the embodiment of FIG. 1, the reflecting device 14 directs the reflected light beam 16 toward the light receiving device 17 substantially along a path in which the light transmitting device 12 directs the inspection light beam 13 toward the reflecting device 14. The reflection device 14 is configured as a triple reflector in the embodiment of FIG.

  Therefore, in the embodiment shown in FIG. 1, the inspection light beam 13 and the reflected light beam 16 coincide with each other, so that the light transmitting device 12 and the light receiving device 17 are integrated into one component. As a result, the waste paper sensor 10 can be incorporated in the sheet-fed printing machine in a particularly space-saving manner. The light transmitting device 12 and the light receiving device 17 and the reflecting device 14 are provided on the opposite sides of the printed sheet 15. The number of reflection devices 14 at the peripheral edge of the transfer drum 11 depends on the number of transfer devices of the transfer drum 11. When the transfer cylinder 11 has two holding systems, one reflecting device 14 is provided correspondingly for each holding system.

  In the embodiment shown in FIG. 1, the inspection beam 13 is directed to the printing sheet transport path at an acute angle α, and the printing sheet 15 is present in the printing sheet transport path. In this case, the print sheet 15 collides with the surface of the print sheet 15 at an acute angle α. Similarly, the reflected light beam 16 collides with the printed sheet surface of the printed sheet 15 at an acute angle α when the printed sheet 15 exists in the printed sheet conveyance path. FIG. 1 shows the damaged paper sensor 10 and the printed sheet 15 as viewed in such a direction that the conveying direction of the printed sheet is a direction penetrating the drawing. Therefore, the acute angle α is formed between the inspection light beam 13 or the reflected light beam 16 and a straight line extending in the vertical direction with respect to the conveyance direction of the printed sheet 15. In this case, the straight line extends parallel to the front edge and the rear edge of the printed sheet 15. According to the invention, this acute angle α is a maximum of 5 degrees. The acute angle α is preferably in the range of 0.5 degrees to 3 degrees.

  Here, the following is guaranteed. That is, when the printed sheet 15 is present in the area to be monitored of the printed sheet conveyance path, the inspection light beam 13 or the reflected light beam 16 is completely absorbed, completely reflected, or Therefore, it is possible to detect the damaged paper more reliably as compared with a state in which the printed sheet 15 is not present in the area to be monitored of the printed sheet conveyance path.

  A second embodiment of the waste paper sensor 18 according to the present invention is shown in FIG. 2 along with a transfer cylinder 19 of a sheet-fed printing machine. Also in the second embodiment of FIG. 2, the damaged paper sensor 18 according to the present invention includes a light transmitting device 20, at least one reflecting device 21, and a light receiving device 22. The light transmitting device 20 transmits the inspection light beam 23 and directs the inspection light beam 23 toward the reflecting device 21 provided corresponding to the transfer cylinder 19 that rotates. When the printed sheet 24 is not present in the printed sheet conveyance path, the inspection light beam 23 reaches the reflecting device 21 and is guided from the reflecting device 21 to the light receiving device 22 as a reflected light beam 25.

  Unlike the embodiment of FIG. 1, in the embodiment of FIG. 2, the reflecting device 24 receives the reflected light beam 25 along a path different from the path in which the light transmitting device 20 directs the inspection light beam 23 toward the reflecting device 21. Turn to. Therefore, in the embodiment of FIG. 2, the light transmitting device 20 and the light receiving device 22 are configured as separate components. In this case, one or each reflection device 21 configured as a mirror in the embodiment of FIG. 2 is provided corresponding to the rotating transfer drum 19 as described above. Here, the number of reflection devices 21 provided corresponding to the transfer drum 19 corresponds to the number of transfer devices of the transfer drum 19.

  In the embodiment of FIG. 2, the reflecting device 21 has the same acute angle α for the inspection light beam 23 and the reflected light beam 25 when the printed paper sheet 24 is present in the area to be monitored of the printed paper sheet conveyance path. The direction of the printed sheet 24 collides with the surface of the printed sheet 24. The acute angle α is a maximum of 5 degrees and is preferably between 0.5 degrees and 3 degrees. The acute angle α is formed between the inspection light beam 23 or the reflected light beam 25 and a straight line extending in the vertical direction with respect to the conveyance direction of the printed sheet 24.

  Even if the reflection device 21 is directed toward the transfer cylinder 19 so that only the inspection light beam 23 or only the reflection light beam 25 forms an acute angle of a maximum of 5 degrees and collides with the printing sheet surface of the printing sheet 24. Point out that it is good. This can be achieved by placing the reflecting device 21 configured as a mirror obliquely with respect to the surface of the transfer cylinder 19.

  1 and 2, the reflecting device 14 or 21 is provided corresponding to the rotating transfer cylinder 11 or 19, respectively, and the printed sheet to be transported in the region of the printed sheet transport path. It is provided below the paper 15 or 24. The light sending device 12 or 20 and the light receiving device 17 or 22 are provided on the side opposite to the printing sheet on the side of the printing sheet conveyance path, and thus above the printing sheet 15 or 24. . Further, the light transmitting device and the light receiving device may be provided above the printed sheet 15 or 24 in the printed sheet transport path. Further, in the embodiment of FIGS. 1 and 2, the inspection light beam 13 or 23 transmitted by the light transmitting device 12 or 20 is not directed to each light receiving device 17 or 22 without any direct or direct contact. There is a common point that the light receiving device 17 or 22 is guided to the corresponding light receiving device 17 or 22 immediately after being reflected by each reflecting device 14 or 21 or through the reflection.

  On the other hand, FIG. 3 shows another embodiment of the waste paper sensor 26 according to the present invention. In this embodiment, the inspection light beam 28 transmitted from the light transmitting device 27 is directed to the light receiving device 29 without any intervention or directly, and the printed sheet 30 is placed in the area to be monitored of the printed sheet conveyance path. Can be received by the light receiving device 29. In this case, the inspection light beam 28 has an acute angle of a maximum of 5 degrees, preferably 0.5 to 3.0 degrees, when the printed sheet 30 is present in the area to be monitored in the printed sheet conveyance path. At a sharp angle between the printed sheet 30 and the printed sheet 30. Again, the acute angle α is formed between the inspection light beam 28 and a straight line extending in the vertical direction with respect to the conveyance direction of the printed sheet 30.

  In the embodiment of FIG. 3, the light transmitting device 27 is provided below the printing sheet 30, and the light receiving device 29 is provided above the printing sheet 30. Alternatively, the light transmitting device 27 may be provided above the printed sheet, and the light receiving device 29 may be provided below the printed sheet. In the embodiment of FIG. 3, both the light transmitting device 27 and the light receiving device 29 are provided in the vicinity of the side of the printed sheet conveyance path. In the embodiment of FIG. 3, the light transmitting device 27 and the light receiving device 29 are fixed to the frame or pedestal of the sheet-fed printing machine via the holding unit 31.

  A further embodiment of the waste paper sensor 32 according to the present invention is shown in FIG. Also in this case, the damaged paper sensor 32 of FIG. 4 includes a light transmitting device 33 and a light receiving device 34. The light transmission device 33 forms an acute angle α of up to 5 degrees, preferably between 0.5 degrees and 3 degrees, and directs the inspection light beam 35 to an area to be monitored in the printed sheet conveyance path. Again, the inspection beam 35 can reach the area of the light receiving device 34 only when the printed sheet 36 is not present in the area to be monitored of the printed sheet transport path. The acute angle α is formed between the inspection light beam 35 and a straight line extending in the vertical direction with respect to the conveyance direction of the printed sheet 36.

  In the embodiment of FIG. 4, at least one optical waveguide 38 is provided correspondingly to a component group that conveys a sheet that is configured as a rotating transfer drum 37. The optical waveguide 38 captures the inspection light beam 35 and guides it in the direction of the light receiving device 34 when the printed sheet 36 is not present in the area to be monitored of the printed sheet conveyance path.

  On the other hand, when the printed sheet 36 is present in the area to be monitored of the printed sheet conveyance path, the inspection light beam is completely absorbed or completely removed as in the other embodiments. Reflected or significantly weakened.

  According to a preferred configuration of the present invention, it is preferable that the light-sending device and the light-receiving device of the waste paper sensor according to the present invention shown in FIGS. 1 to 4 are integrated in a tubular light transmitting part (Roehrenblende). . Alternatively, the tubular light transmitting part may be placed in front of the light sending device and light receiving device of the waste paper sensor. By doing so, the light receiving device and the light transmitting device can be protected from contamination. Furthermore, such a tubular translucent part functions as a disturbance light trap (Fremdlichtfallen), thereby improving the quality of paper loss detection.

  This type of tubular translucent part can be provided, for example, by providing through holes in the side frame of a sheet-fed printing machine and inserting a light transmitting device and a light receiving device into these through holes. Such a through hole can be provided by drilling a side frame. These perforations are sufficiently accurate to position the light transmitting device and the light receiving device relative to each other or to the reflecting device.

  According to the present invention, after the installation or operation of the damaged paper sensor, the signal level can be generated by the lost paper sensor when there is no printed sheet in the area to be monitored of the printed sheet conveyance path. . This signal level corresponds to the maximum level of the light sending device of the waste paper sensor. When each coating machine is started, immediately after the start of operation of the coating machine, if there is no printed sheet in the area to be monitored in the printing sheet conveyance path, the new signal level of the light receiving device Is detected. After starting the waste paper sensor, this actual level is compared with the maximum level, and if the actual level deviates from the maximum level by an acceptable limit, the waste paper sensor should be cleaned A message that conveys the effect is generated.

  In this case as well, determining whether or not a printed sheet exists in the area to be monitored of the printed sheet conveyance path is performed by comparing the signal level of the light receiving device of the damaged sheet sensor with a threshold value. Is called. At that time, it is preferable to evaluate a plurality of signal levels each time the printed sheet is scanned in order to improve the signal-to-noise ratio and thus improve the detection quality. A further improvement in measurement safety is that for each clock operation, two measurements are taken, ie a measurement to evaluate the situation when the printed sheet is present in the area to be monitored of the printed sheet transport path. And a second measurement for assessing the situation when no printed sheet is present can be achieved by comparing with each other.

  A light loss sensor light transmission device according to the present invention for transmitting an optical inspection beam can be configured, for example, as a laser diode or other light source. It is preferable to use a light source having the smallest possible diameter of the inspection beam to be transmitted.

  The operation of the waste paper sensor according to the present invention is preferably triggered by the real-time machine control unit of the printing sheet processing machine in synchronization with the clock operation of the printing sheet processing machine. Alternatively, however, the lost paper sensor may be activated independently of the real-time machine control of the printed sheet and thus independent of the clock operation. In this case, the signal of the waste paper sensor is continuously inquired and evaluated. The waste paper evaluation in this case may be based on duplication information.

  Hereinafter, an example in which the waste paper sensor can be operated independently or separately will be described with reference to FIG. FIG. 5 shows a waste paper sensor 39, which includes a light transmitting device 40 and a light receiving device 41. In this case as well, the sensor 39 is used to check whether or not the print sheet 42 exists in the area to be monitored of the print sheet transport path.

  According to FIG. 5, the printed sheet 42 is guided and conveyed in the direction of the arrow 44 by the holding system 43. Activating the spoilage sensor 39 independently of the real-time machine controller of the printing sheet processing machine is preceded by a coded system translucent part 45 having differently shaped openings. Is realized. The light transmitting portion 45 moves along the arrow 44 together with the holding system 43.

  The inspection light beam 46 transmitted by the light transmitting device 40 in the direction of the light receiving device 41 is interrupted by the light transmitting portion 45 in a state depending on the shape and size of the opening of the light transmitting portion 45. In this case, the elapsed time of the interruption is a time code of the operation of the waste paper sensor. As a result, the sensor is automatically activated, calculates the inquiry time, and checks whether or not the printed sheet 42 exists in the holding system 43.

  In the embodiment of FIG. 5 also, when the printing sheet exists in the area to be monitored of the printing sheet conveyance path, the inspection light beam 46 collides with the surface of the printing material at an acute angle α. Also in this case, the acute angle α is formed between the inspection light beam 46 and a straight line extending in the vertical direction with respect to the conveyance direction 44 of the printed sheet 42, so that it cannot be seen in the view of FIG. 5. ing.

  1 to 4, the present invention will be described based on an example in which each damaged paper sensor is used in a group of components that convey a sheet that is configured as a transfer cylinder of a sheet printing machine. However, it should be noted that the waste paper sensor according to the present invention is not limited to these applications. The waste paper sensor according to the present invention may be used in a direction change cylinder (Wendezylinder), a paper discharge system, a loading drum, or a sheet travel direction changer (Bogenweiche) of a sheet printing machine.

  FIG. 6 shows one possible implementation of the waste paper sensor arranged in the area of the direction change cylinder 47. As in the embodiment of FIG. 1, the waste paper sensor includes a light transmitting device 48 and a light receiving device 49 that are integrated into one component member, and a reflecting device 50. In the embodiment of FIG. 6 also, when the printed sheet 54 is present in the area to be monitored of the printed sheet conveyance path, the inspection light beam 51 or the reflected light beam 52 forms an acute angle α on the surface of the printing material. collide. Also in this case, the acute angle α is formed between the inspection light beam 51 or the reflected light beam 52 and a straight line extending in the vertical direction with respect to the conveyance direction 53 of the printed sheet 54. It is invisible. In addition, when applied to a turning cylinder, the inspection light beam 51 or the reflected light beam 52 tilts at an acute angle β on the second surface, so that the turning cylinder 47 can change the direction. At this time, even the printed sheet 54 extending substantially in the vertical direction can be reliably detected. In this case, the angle β is preferably the same size as the angle α, and is preferably 5 degrees at the maximum.

It is the schematic which showed the loss paper sensor by this invention based on 1st Example of this invention with the structural member group which conveys the sheet of a printing sheet processing machine. It is the schematic which showed the loss paper sensor by this invention based on the 2nd Example of this invention with the structural member group which conveys the sheet of a printing sheet processing machine. It is the schematic which showed the loss paper sensor by this invention based on the 3rd Example of this invention with the structural member group which conveys the sheet of a printing sheet processing machine. It is the schematic which showed the loss paper sensor by this invention based on the 4th Example of this invention with the structural member group which conveys the sheet of a printing sheet processing machine. It is the schematic which showed the loss paper sensor by this invention based on the 5th Example of this invention with the structural member group which conveys the sheet of a printing sheet processing machine. It is the schematic which showed the waste paper sensor by this invention based on the 6th Example of this invention with the structural member group which conveys the sheet of a printing sheet processing machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Waste paper sensor 11 Transfer cylinder 12 Light transmission apparatus 13 Inspection light 14 Reflection apparatus 15 Printing sheet 16 Reflection light 17 Light reception apparatus 18 Paper loss sensor 19 Delivery cylinder 20 Light transmission apparatus 21 Reflection apparatus 22 Light reception apparatus 23 Inspection light 24 Printing Sheet paper 25 Reflected light beam 26 Damaged paper sensor 27 Light transmission device 28 Inspection light beam 29 Light receiving device 30 Printing sheet 31 Holding unit 32 Paper loss sensor 33 Light transmission device 34 Light receiving device 35 Inspection light beam 36 Printing paper sheet 37 Transfer cylinder 38 Light Wave Guide 39 Damaged Paper Sensor 40 Light Transmitting Device 41 Light Receiving Device 42 Printed Sheet Paper 43 Holding System 44 Arrow 45 Light Transmitting Section 46 Inspection Light 47 Direction Changing Cylinder 48 Light Transmitting Device 49 Light Receiving Device 50 Reflecting Device 51 Inspection Light 52 Reflected beam 53 Transport direction 54 Printed sheet

Claims (19)

A paper loss sensor for a printing sheet processing machine, in particular a sheet printing machine,
A light transmission device (12; 20; 27; 33; 40; 48), wherein the optical inspection beam is directed in particular to the area to be monitored of the printed sheet transport path;
The light receiving device (17; 22; 29; 34; 41; 49), and the inspection light beam (28) only when there is no printed sheet in the area to be monitored of the printed sheet transport path. 35; 46) or a light receiving device adapted to receive the inspection light beam (13; 23; 51) reflected by the reflection device (14; 21; 50) as a reflected light beam (16; 25; 52); In a waste paper sensor comprising:
The inspection light beam (13; 23; 28; 35; 46; 51) and / or the reflected light beam (16; 25; 52) is present in the print sheet in the area to be monitored in the print sheet conveyance path. When this occurs, the paper loss sensor is characterized by colliding with the surface of the printed sheet at an acute angle of a maximum of 5 degrees.   2. The damaged paper sensor according to claim 1, wherein the inspection light beam and / or the reflected light beam strikes a printed sheet surface at an acute angle between 0.5 degrees and 3 degrees, Waste paper sensor.   3. The paper loss sensor according to claim 1 or 2, wherein the light receiving device (17; 22; 49) is configured such that when there is no printed sheet in the area to be monitored in the printed sheet conveyance path. Only the inspection light beam (13; 23; 51) reflected by the reflection device (14; 21; 50) is received directly or indirectly as reflected light beam (16; 25; 52). A waste paper sensor.   4. The damaged paper sensor according to claim 3, wherein at least one reflection device (14:21; 50) is provided corresponding to each of the component members that convey the sheet, A damaged paper sensor, which is provided for a printed sheet to be conveyed in a printed sheet conveyance path.   5. The waste paper sensor according to claim 3 or 4, wherein one or each reflecting device (14; 50) is such that the light transmitting device (12; 48) emits an inspection beam (13; 51). A waste paper sensor, characterized in that the reflected light beam (16; 52) is directed to the light receiving device (17; 14) substantially along a path that is directed to the light receiving device (17; 14).   6. The waste paper sensor according to claim 5, wherein one or each reflector (14; 50) is configured as a triple reflector.   The paper loss sensor according to claim 5 or 6, wherein the light transmitting device (12) and the light receiving device (17) are integrated into one component member.   5. The waste paper sensor according to claim 3, wherein one or each reflecting device (21) is a path through which the light transmitting device (20) directs the inspection light beam (23) toward the reflecting device (21). A waste paper sensor, characterized by directing the reflected light beam (25) to the light receiving device (22) along a different path.   9. A waste paper sensor according to claim 8, characterized in that one or each reflector (21) is configured as a mirror.   The damaged paper sensor according to claim 8 or 9, wherein the light transmitting device (20) and the light receiving device (22) are configured as separate constituent members, and are arranged in the printed sheet transport path. A waste paper sensor, which is provided in regions on different sides facing each other.   3. The paper loss sensor according to claim 1 or 2, wherein the light receiving device (29; 34; 41) is used only when a printing sheet is not present in an area to be monitored of the printing sheet conveyance path. The paper loss sensor, wherein the inspection light beam (28; 35; 46) is received directly or without anything.   12. The paper loss sensor according to claim 11, wherein the light transmitting device (27; 33; 40) is provided above or below a printed sheet, and the light receiving device (29; 34; 41). Is provided on the opposite side of the printed sheet.   13. The paper loss sensor according to claim 11 or 12, wherein the printing sheet conveyance path is at least one light wave guide path (38) provided corresponding to a component group for conveying a sheet. Characterized by a lightwave path adapted to capture the inspection beam (35) and direct it in the direction of the light receiving device (34) when no printed sheet is present in the area to be monitored A waste paper sensor.   14. The damaged paper sensor according to claim 1, wherein the light transmitting device and the light receiving device are provided above or below a printing sheet to be conveyed in the printing sheet conveyance path. A waste paper sensor.   14. The damaged paper sensor according to claim 1, wherein the light transmitting device and the light receiving device are located outside the printing sheet transport path and lateral to the printing sheet transport path. A damaged paper sensor, which is provided above or below a printed sheet to be conveyed.   16. The waste paper sensor according to claim 1, wherein the light transmitting device (12; 20; 27; 33; 40) and the light receiving device (17; 22; 29; 34; 41) are: It is integrated with the tubular light transmitting part, or a tubular light transmitting part is placed in front of the light transmitting device and the light receiving device, whereby the light transmitting device (12; 20; 27; 33). 40) and a waste paper sensor adapted to minimize contamination and / or external influences of the light receiving device (17; 22; 29; 34; 41).   17. The paper loss sensor according to claim 1, wherein the paper loss sensor is operable in synchronization with a clock operation by a machine control unit of a printing sheet processing machine. A waste paper sensor.   17. The paper loss sensor according to claim 1, wherein the paper loss sensor is operable independently or separately from a clock operation of a printing sheet processing machine. A waste paper sensor.   19. The paper loss sensor according to claim 1, wherein the maximum level of the light receiving device (17; 22; 29; 34; 41) can be recorded after the operation of the paper loss sensor is started. At that time, each time the machine is started, the actual level of the light receiving device can be compared with the maximum level, and if the actual level deviates from the maximum level by an allowable limit value, a warning message or maintenance A waste paper sensor, characterized in that a message can be generated.

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