JP7240237B2 - Printer - Google Patents

Description

The present invention relates to printing presses.

Such a printing press includes a plate cylinder around which a plate is wound, and a drivable plate feeding device for moving the plate toward the plate cylinder. When the plate is moved toward the plate cylinder, a registration pin (also called a positioning pin) is provided with which the front end of the plate in the direction of movement engages and is positioned with respect to the plate cylinder.

A detecting means is provided for detecting whether or not the plate is correctly positioned with respect to the plate cylinder when the plate is moved toward the plate cylinder by driving the plate feeding device. This detection means is configured using a registration pin. Specifically, a solenoid coil and a mover movable in the solenoid coil are arranged on the registration pin, and the mover moves inside the solenoid coil by being pushed by the leading end in the moving direction of the plate moved by the plate feeding device. By moving, the position of the front end of the plate in the direction of movement is detected, and whether or not the front end of the plate in the direction of movement is correctly positioned with respect to the plate cylinder is detected (for example, Patent Document 1). ).

JP-A-2000-289188

In Patent Document 1, the ink from the ink roller sometimes adheres to the register pin, which impairs the movement of the mover, and it is necessary to check whether the tip of the plate in the movement direction is correctly positioned with respect to the plate cylinder. In some cases, the detection accuracy for detecting whether or not is deteriorated.

In addition, a special signal transmission means such as a slip ring is provided on the rotation shaft of the plate cylinder in order to transmit the signal from the detecting means arranged on the rotating plate cylinder to the control unit arranged outside the plate cylinder. This is disadvantageous in terms of manufacturing, and an early improvement is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing machine that prevents deterioration in detection accuracy and is advantageous in terms of manufacturing.

In order to achieve the above object, a printing press according to the present invention is a printing press comprising a plate cylinder around which a plate is wound, and a drivable plate feeding device for moving the plate toward the plate cylinder. and a sensor that is spaced apart from the plate cylinder and detects a distance to a portion of the plate cylinder where the leading edge of the plate in the direction of movement of the plate is located when the plate feeding device is driven.

According to the above configuration, the sensor detects the distance to the portion where the moving direction leading edge of the plate moved by driving the plate feeding device is located. Then, the difference between the distance detected by the sensor and the preset (measured) distance of the normal position of the plate when the leading end of the plate in the moving direction is positioned at the normal position with respect to the plate cylinder is obtained, By judging whether or not the difference is within the allowable range, it can be judged whether or not the front end portion of the plate in the moving direction is correctly positioned with respect to the plate cylinder. Moreover, since the sensor is provided at a distance from the plate cylinder, there are problems that occur when the detection means is provided on the plate cylinder itself, such as a deterioration in detection accuracy due to ink adhesion and a slip ring or the like on the rotation shaft of the plate cylinder. Disadvantages in terms of cost due to provision of special signal transmission means can be eliminated.

Further, in the printing press according to the present invention, the plate cylinder includes a gripping side vise for gripping a leading end portion of the plate moved in the moving direction by driving the plate feeding device, and the plate is moved by the driving of the plate feeding device. The portion of the cylinder where the front end portion of the plate in the moving direction is located may be the portion of the grip side vice.

As described above, if the tip of the plate in the direction of movement is located in the gripping side vice, there is no need to provide a special member or the like necessary for detecting the plate, which facilitates design.

Further, the printing press according to the present invention may include an openable and closable safety cover arranged so as to cover the plate cylinder, and the sensor may be attached to the safety cover.

As mentioned above, since the sensor is attached to the safety cover that can be opened and closed freely, when the safety cover is opened during inspection and maintenance of the plate cylinder, the sensor moves together with the safety cover, so the sensor does not become an obstacle during inspection and maintenance. There is no

Further, in the printing press according to the present invention, the plate cylinder is provided with a trailing edge side vise for gripping the trailing end portion of the wound plate in the moving direction, and the sensor is provided at the portion of the edge side vise. A configuration for detecting the distance to the portion where the moving direction front end of the plate is located, and detecting the distance to the portion where the moving direction rear end of the plate is located by the portion of the tail edge side vise. good too.

A sensor detects the distance to the part where the front end of the plate in the moving direction is located in the grip side vise, and to the part where the rear end in the moving direction of the plate is located in the trailing edge side vise. is detected by a sensor, it is possible to determine whether the plate is securely attached to the plate cylinder. In this case, the distance detected by the sensor and the preset normal position of the plate when the ends of the plate (leading edge in the moving direction and trailing edge in the moving direction) are positioned at the normal positions with respect to the plate cylinder Find the difference from the (measured) distance, and determine whether the difference is within the allowable range. It can be determined whether it is located Further, if the sensor detects the trailing end portion in the direction of movement of the plate at the portion of the grip side vise, there is no need to provide a special member or the like required for detection, and design is easy.

According to the present invention, the sensor provided outside the plate cylinder detects the distance to the plate in the portion where the leading edge of the plate in the direction of movement is located, thereby preventing the detection accuracy from deteriorating. An advantageous printing machine can be provided.

FIG. 2 is a side view showing a main part of a printing section provided in the printing press; FIG. 4 is a side view of a main portion showing a state in which a plate is normally gripped by a gripping side holding portion provided in the printing section; It is a side view of the principal part which shows the state where the printing plate stopped before the edge side holding part provided in the same printing part. FIG. 4 is a side view of the main part showing a state in which a plate has run on the first gripping plate of the gripping side holding portion provided in the same printing section; FIG. 4 is a side view of the main part showing a state in which the trailing edge side end portion of the plate wound around the plate cylinder is normally held by the trailing edge side holding portion; FIG. 5 is a side view of the main part showing a state in which the trailing edge side end of the plate wrapped around the plate cylinder is not gripped by the trailing edge side holding portion; FIG. 5 is a side view of the main part showing a state immediately before the trailing edge side end portion of the plate wound around the plate cylinder is gripped by the trailing edge side holding portion; It is a front view of a plate cylinder. FIG. 3 is a perspective view of the main part of the plate cylinder; FIG. 5 is a side view of the main part of the printing section showing a state in which the safety cover is positioned at the upper open position;

Hereinafter, the printing press of the present invention will be described with reference to the drawings.

The printing press has a paper feeding section (not shown) on the upstream side, a paper discharging section (not shown) on the downstream side, and a printing section (also called a printing unit) (not shown) disposed between them. are doing. Although the number of printing units is equal to the number of ink colors used for printing, only one printing unit will be described here.

As shown in FIG. 1, the printing unit includes a main body 2 having left and right side walls 1 (only one side wall 1 is shown in FIG. 1), and a plate cylinder that is installed inside the main body 2 and around which a plate 3 is wound. 4 , a plurality of ink rollers 5 for supplying ink to the plate cylinder 4 , and a plate feeder 6 for supplying the plate 3 to the plate cylinder 4 . The plate cylinder 4 is rotatably supported by the left and right side walls 1, 1 of the main body 2. As shown in FIG. Also, a blanket cylinder (also called a blanket cylinder) 7 is arranged so as to be in rolling contact with the plate cylinder 4 . An impression cylinder (not shown) is rotatably disposed on the blanket cylinder 7, and the ink on the blanket cylinder 7 is transferred to the printing paper conveyed by the impression cylinder. The plate feeding device 6 also functions as a plate discharging device for discharging the plate 3 from the plate cylinder 4 .

The main body 2 is provided with a safety cover 8 covering the downstream side between the side walls 1, 1, that is, the downstream side (the left side in the figure) of the plate cylinder 4 in the printing paper conveying direction. The safety cover 8 is attached between the side walls 1, 1 so as to be vertically movable (liftable). Therefore, by moving the safety cover 8 upward using a manual force or an electric force, the downstream lower part between the side walls 1, 1 can be opened (see FIG. 10), and the inside of the main body 2 can be inspected. I'm trying The plate feeder 6 is supported by a safety cover 8. As shown in FIG.

A concave groove 9 is formed in the plate cylinder 4 over substantially the entire width direction, and the moving direction leading end (the gripping side end) of the plate 3 is held in the groove 9 in order to wind the plate 3 around the peripheral surface. The trailing edge side holding portion 10 and the trailing edge side holding portion 11 which holds the moving direction rear end portion (the trailing edge side end portion) of the plate 3 wound around the plate cylinder 4 are arranged in pairs in the circumferential direction. are placed.

The leading edge side holding portion 10 is composed of a leading edge side vise that grips the leading edge side end portion of the plate 3 . This gripping side vise is composed of a first vise 10A fixed upstream in the rotational direction of the plate cylinder 4 in the groove 9, and a first vise placed facing the first vise 10A. Five plates on the gripper side whose position can be changed between a closed position in which one end of the plate 3 is held in a state of being sandwiched between the table 10A and an open position in which the state in which the gripper side end of the plate 3 is sandwiched is released. and a first gripping plate 10B (see FIG. 8). The plate 3 is wound around the plate cylinder 4 by driving and rotating the plate cylinder 4 by a predetermined angle while holding the leading end of the plate 3 with the leading edge side holding portion 10 .

The trailing edge side holding portion 11 is composed of a trailing edge side vise for gripping the trailing edge side end of the plate 3 wound around the plate cylinder 4, as described above. The trailing edge side vise is composed of a second vise 11A fixed downstream in the rotational direction of the plate cylinder 4 in the groove 9, and a second vise 11A arranged to face the second vise 11A. The position of the jaws can be changed between a closed position where the trailing edge side of the plate 3 is held in a state of being pinched by the force stand 11A and an open position where the trailing edge of the plate 3 is released from the pinched state. and two second gripping plates 11B (see FIG. 8) on the tail side. Further, the tail edge side holding portion 11 is configured to be movable by a moving mechanism (not shown). As a result of this movement, the leading edge side end of the plate 3 is sandwiched between the leading edge side holding portion 10 and the trailing edge side end portion of the plate 3 is sandwiched by the trailing edge side holding portion 11, respectively, and the plate is wound around the plate cylinder 4. 3 can be tensioned.

When the plate cylinder 4 is driven and rotated counterclockwise by a predetermined angle to wind the plate 3 around the plate cylinder 4, the pressing roller 12 is moved to press the plate 3 against the plate cylinder 4 while the plate 3 is being pushed onto the plate cylinder 4. wrap around. When the winding of the plate 3 is completed, the blade 13 (see FIG. 7) moves to press the trailing edge side end 3B of the plate 3 against the second clamp 11A, and then the second jaw plate 11B at the open position. , 11B are changed to the closing side, and the trailing edge side end portion 3B of the plate 3 is held by the trailing edge side holding portion 11.例文帳に追加When the trailing edge side end 3B of the plate 3 is held by the trailing edge side holding portion 11, the pressing roller 12 and the blade 13 move away from the plate cylinder 4. As shown in FIG. After the pressing roller 12 and the blade 13 are moved, the plate cylinder 4 is rotated by a predetermined angle, and then a laser displacement sensor 19 (to be described later) detects that the trailing edge side end 3B of the plate 3 is in the trailing edge side holding portion 11. It detects whether it is sandwiched between In this embodiment, the plate cylinder 4 is rotated by a predetermined angle so that the trailing edge 3B of the plate 3 can be easily detected by a laser displacement sensor 19, which will be described later. After the blade 13 moves away from the plate cylinder 4, a laser displacement sensor 19, which will be described later, may be used to detect the trailing edge 3B of the plate 3 immediately.

The plate feeder 6 includes a plate guide plate 14 for guiding the back side of the plate 3, a plurality of rotatable rubber rollers 15 facing the plate guide plate 14 for smoothly guiding the front side of the plate 3, and a feeder. A clamping member (not shown) that clamps the plate 3 set in the plate unit 6 at both ends in the width direction, and an air cylinder (not shown) for moving the plate 3 clamped by the clamping member to the plate cylinder 4 side. ), and In this embodiment, the plate feeding device 6 that holds the plate 3 between holding members is shown. It may be a device.

The plate supply device 6 is configured to be swingable about the left and right axis on the upper side, and is swung by telescopic air cylinders 17 (see FIG. 1) provided on both sides of the downstream front plate 16 respectively. That is, the operation of the air cylinder 17 causes the plate feeder 6 to move the lower end away from the plate cylinder 4 to set the plate 3 in a vertical setting posture (the outer surface of the plate 3 is substantially flush with the downstream front plate 16 shown in FIG. 2). ) and a plate feeding posture (see the posture in FIG. 1) for moving the plate 3 to the printing cylinder 4 (plate feeding) in an inclined posture where the lower end approaches the plate cylinder 4 (see the posture of FIG. 1). It is

The first vise 10A serves as a positioning portion for positioning the plate 3. A pair of columnar projections 18, 18 (see FIG. 1) are separated from each other by a predetermined distance in the axial direction of the plate cylinder 4 (hereinafter referred to as the width direction). , only one of which is shown in FIG. In addition, although not shown, a substantially semicircular notch is formed in the edge of the plate 3 on the gripper side as a recess for positioning, and serves as a portion to be positioned to be engaged with the projections 18 , 18 . Therefore, by driving the plate feeding device 6, the plate 3 is moved to the plate cylinder 4, and the pair of notches at the leading edge side end of the plate 3 are engaged with the projections 18, 18, whereby the leading edge side of the plate 3 is moved. The part is positioned in the normal position.

In the printing press of this embodiment, the distance to the portion where the edge side edge of the plate 3 positioned at the regular position of the edge side vise (the edge side holding portion 10) of the plate cylinder 4 is non-contact sensor as a sensor for detecting the distance to the part where the trailing edge of the correctly wound plate 3 of the trailing edge side vise (the trailing edge side holding portion 11) of the plate cylinder 4 is located. A laser displacement sensor 19 of the formula is provided. The laser displacement sensors 19 are provided at two locations spaced apart in the rotation axis direction (width direction) of the plate cylinder 4 . It is detected whether or not the plate 3 is positioned at the correct position at two positions spaced apart in the width direction or at two positions spaced apart in the width direction of the tail edge portion 3B of the plate 3 . 8 and 9 show the irradiation positions of the laser beams of the laser displacement sensors 19 and 19. FIG. That is, the laser displacement sensors 19, 19 irradiate the positions of the cutouts 20A, 20B respectively formed on the upper sides of the first gripping plates 10B, 10B located on both widthwise end sides in FIG. . Based on the amount of reflected light, it is detected whether or not the leading edge 3A of the plate 3 is positioned at the correct position. Further, the laser displacement sensors 19, 19 irradiate the positions of the cutouts 21A, 21B respectively formed on the lower sides of the second gripping plates 11B, 11B with laser light. Then, based on the amount of reflected light, it is detected whether or not the tail edge portion 3B of the plate 3 is positioned at the proper position. In this manner, the leading edge side vise (the leading edge side holding portion 10) is provided with the notched portions 20A and 20B, and the trailing edge side vise (the trailing edge side holding portion 11) is provided with the notched portions 21A and 20B. Since only the 21B is provided, the edge of the plate 3 can be detected without using any special members.

A pair of laser displacement sensors 19, 19 are arranged apart from the plate cylinder 4 (outside the plate cylinder 4). Specifically, it is attached to the safety cover 8 via a bracket 22 . Since the laser displacement sensors 19 and 19 are attached to the openable/closable safety cover 8 in this way, for example, when the plate cylinder 4 is inspected and maintained, the safety cover 8 can be opened as shown in FIG. Since the laser displacement sensors 19, 19 move together with 8, the laser displacement sensors 19, 19 do not become an obstacle during inspection and maintenance. In this embodiment, since the safety cover 8 is lifted upward, there is an advantage that the sensor is not exposed to solvent or detergent used for the plate cylinder 4 or blanket cylinder 7 during maintenance.

Each laser displacement sensor 19 is mounted so as to irradiate a laser beam obliquely upward, and as shown in FIG. are irradiated so as to be substantially perpendicular to each other. On the other hand, as shown in FIG. 6, the trailing edge 3B of the plate 3 wrapped around the plate cylinder 4 is obliquely irradiated with laser light, but there is no problem with the detection accuracy. , is equivalent to the detection accuracy when detecting the leading edge 3A of the plate 3. Each of the laser displacement sensors 19, 19 detects (calculates) the distance to the reflection position by receiving the reflected and returned laser light. Then, the normal position when the tip of the plate 3 in the moving direction (the leading edge side end 3A) is positioned at a normal position with respect to the leading edge side vise of the plate cylinder 4 (the leading edge side holding portion 10). (a distance measured in advance or a distance set by calculation) is detected. Based on the amount of displacement, it is determined whether or not the leading edge 3A of the plate 3 is correctly positioned with respect to the leading edge vice of the plate cylinder 4 (the leading edge holding portion 10). Specifically, it is determined whether or not the displacement amount is within a preset allowable range. It is determined that the position is correct with respect to the vise (the gripping side holding portion 10), and if it is out of the allowable range, the gripping side end portion 3A of the plate 3 is positioned against the gripping side vise of the plate cylinder 4 (the gripping portion 10). It is judged that it is not positioned correctly with respect to the holding part 10). If it is determined that the leading edge 3A of the plate 3 is not positioned correctly with respect to the leading edge vice of the plate cylinder 4 (the leading edge holding portion 10), the plate 3 is not properly inserted. The operator may be notified using a notification means such as a buzzer or a lamp.

2 to 4 show the case where the position of the leading edge of the plate 3 is detected by the laser displacement sensor 19. FIG. First, FIG. 2 shows a case where the leading edge side end portion 3A of the plate 3 is correctly positioned with respect to the leading edge side vise of the plate cylinder 4 (the leading edge side holding portion 10). In this case, the gripping side end portion 3A of the plate 3 is inserted between the first clamping table 10A and the first gripping plate 10B by driving the plate feeding device 6, and the projections 18, 18 are engaged with the plate as described above. The displacement amount detected by the laser displacement sensor 19 is within the allowable range when the notch (not shown) of the leading edge portion 3A of the plate 3 is locked and the leading edge portion of the plate 3 is positioned. Therefore, it is determined that the plate 3 can be inserted, and the operation of winding the plate 3 can be started.

FIG. 3 shows the case where the leading edge side end 3A of the plate 3 is not positioned correctly with respect to the leading edge side vise of the plate cylinder 4 (the leading edge side holding portion 10). In this case, the gripping side end portion 3A of the plate 3 is not inserted between the first gripping plate 10A and the first gripping plate 10B by driving the plate feeding device 6, and the gripping side vise (gripping side In this state, the plate 3 stops moving before the holding portion 10). In this state, the laser beam emitted from the laser displacement sensor 19 does not hit the gripping side end portion 3A of the plate 3, but hits the part 23 behind the notch portion 20A farther from the laser displacement sensor 19 and is reflected. Since the detected distance becomes longer, the above displacement amount is out of the allowable range, and it is determined that the plate 3 is not properly inserted. For example, the plate feeding process is stopped and the notification means is activated.

Similarly to FIG. 3, FIG. 4 also shows a case where the leading edge side end of the plate 3 is not correctly positioned with respect to the leading edge side vise (the leading edge side holding portion 10) of the plate cylinder 4. FIG. In this case, the leading edge portion 3A of the plate 3 is not inserted between the first clamping table 10A and the first gripping plate 10B by driving the plate feeding device 6, and the leading edge portion 3A of the plate 3 is not inserted. is bent over the first gripping plate 10B. In this state, the laser beam emitted from the laser displacement sensor 19 hits the gripping side edge portion 3A of the plate 3 located on the left side of the paper surface of the first gripping plate 10B and is reflected. Therefore, the above displacement amount is out of the allowable range, and it is determined that the plate 3 is not properly inserted. For example, the plate feeding process is stopped and the notification means is activated.

5 and 6 show the case where the laser displacement sensor 19 detects the position of the trailing edge 3B of the plate 3. FIG. In FIG. 5, since the leading edge 3B of the plate 3 is well held by the trailing edge side vise (the trailing edge side holding portion 11) of the plate cylinder 4, the irradiated laser beam 19A is applied to the plate 3. Since the detected displacement amount is within the permissible range, it is determined that the clamping of the plate 3 with the tail edge vise is OK, and tension is applied to the next plate 3. It is possible to shift to the step of imparting.

FIG. 6 shows a case where the laser beam 19A irradiated to the plate 3 does not hit the trailing edge portion 3B of the plate 3. As shown in FIG. In this case, the laser beam 19A hits the part 24 behind the notch 21A farther from the laser displacement sensor 19 and is reflected. Therefore, it is determined that the distance is long, that is, the above-described displacement amount is outside the allowable range, and the trailing edge side end 3B of the plate 3 is satisfactorily held by the trailing edge side vise (the trailing edge side holding portion 11). determined not to be retained. Also, although not shown, when the laser beam 19A hits the trailing edge side end 3B of the plate 3 which is not held by the trailing edge side vise (the trailing edge side holding portion 11), the distance increases. It is detected that it is short, that is, the amount of displacement described above is outside the allowable range, and the trailing edge side end 3B of the plate 3 is not held satisfactorily by the trailing edge side vise (the trailing edge side holding portion 11). is judged. If it is determined that the plate is not held well, for example, the plate feeding process is stopped and the notification means is activated.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

For example, in the above-described embodiment, the laser displacement sensor 19 is used as the displacement sensor, but an eddy current type, an ultrasonic type, or a capacitance type may be used. In addition to the non-contact type displacement sensor, a contact type displacement sensor may be used. In the case of this contact type, each time the distance is detected, the object (here, the plate 3) is extended to the position where it contacts, the distance is detected from the contact position, and the distance from the plate 3 at the normal position is extended. It may be detected that the plate 3 is positioned at the correct regular position based on the amount of displacement. In addition to detecting the distance to the plate 3 with a sensor, the configuration may be such that detection information detected by the sensor is input to the control unit and the control unit detects the distance to the plate 3 .

In the above-described embodiment, the displacement sensor is configured to detect both the leading edge 3A and trailing edge 3B of the plate 3, but only the leading edge 3A of the plate 3 is detected. It may be configured to Further, by providing a plurality of displacement sensors (two in the embodiment, but may be three or more) so as to detect two locations spaced apart in the width direction of the plate 3, both ends 3A and 3B of the plate 3 can be detected. It can be detected whether or not the plate 3 A single displacement sensor may be provided to detect only one position in the width direction of the .

Further, in the above embodiment, the displacement sensor (laser displacement sensor 19) is attached to the safety cover 8, but the displacement sensor may be attached to a bracket extending from the side wall 1 instead of the safety cover 8, for example.

Further, in the above-described embodiment, when the leading edge side end portion 3A or the trailing edge side edge portion 3B of the plate 3 is not positioned at the proper position, the component 23 or the leading edge located at the back of the leading edge side holding portion 10 may be displaced. When the trailing edge side end 3A or trailing edge side end 3B of the plate 3 is positioned at the correct position by detecting the distance to the component 24 at the back of the trailing edge side holding portion 11 with a sensor. , and there is an advantage that it is possible to accurately determine whether or not the leading edge 3A or trailing edge 3B of the plate 3 is positioned at a proper position. It may be determined whether or not the leading edge 3A or trailing edge 3B of the printing plate 3 is positioned at the correct position based on the difference in distance corresponding to the thickness of . That is, when the gripping side end 3A or the trailing edge side end 3B of the plate 3 is not positioned at the proper position, the irradiated light is not applied to the first vise 10A or the second vise 11A. It hits a surface that is flush with the surface holding the plate 3, and the distance is calculated from the amount of reflected light, but the distance is longer by the thickness of the plate 3 than the distance to the plate 3 at the normal position. Therefore, there is a possibility that an error may occur in determining whether or not the leading edge 3A or trailing edge 3B of the plate 3 is positioned at a proper position. Therefore, in the case of this configuration, it is desirable to use a laser displacement sensor, which is a sensor with high detection accuracy.

DESCRIPTION OF SYMBOLS 1... Side wall, 2... Main body, 3... Plate, 3A... Leading side end, 3B... Leading edge side end, 4... Plate cylinder, 5... Ink roller, 6... Plate feeder, 7... Rubber cylinder, 8 Safety cover 9 Groove 10 Gripping side holding portion 10A First vise base 10B First gripping plate 11 Tail tail side holding portion 11A Second vise base 11B Second gripping plate 12 Presser roller 13 Blade 14 Plate guide plate 15 Rubber roller 16 Downstream front plate 17 Air cylinder 18 Protrusion 19 Laser displacement sensor 19A ... laser light 20A, 20B ... notch 21A, 21B ... notch 22 ... bracket 23, 24 ... parts

Claims (3)

A printing press comprising a plate cylinder on which a plate is wound and a drivable plate feeder for moving the plate toward the plate cylinder ,
The plate cylinder is provided with a gripping side vise that grips the moving direction leading end of the plate moved by the plate feeding device and a gripping trailing side vise that grips the moving direction trailing end of the wrapped plate. ,
The distance to the tip of the plate in the moving direction is detected by the edge side vise portion, and the edge portion of the edge side vise portion is arranged to be spaced apart from the plate cylinder. A printing press comprising a sensor for detecting a distance to a portion where a trailing end in a moving direction is positioned . 2. The printing machine according to claim 1 , further comprising an openable and closable safety cover arranged so as to cover said plate cylinder, and said sensor being attached to said safety cover. A printing press comprising a plate cylinder on which a plate is wound and a drivable plate feeder for moving the plate toward the plate cylinder,
The plate cylinder is provided with a gripping side vise that grips the leading end portion of the plate moved in the movement direction by driving the plate feeding device,
The gripper-side vise includes a gripper plate and a vise base, and has a configuration in which a leading end portion of the plate in a moving direction is held between the gripper plate and the vise base, and the gripper plate A notch is formed in the
The plate spaced apart from the plate cylinder and positioned between the clamping plate and the vise due to the amount of light reflected by irradiating light onto the position of the notch. Equipped with a sensor that detects the distance to the tip of the movement direction,
When the front end of the plate in the direction of movement is not positioned between the clamping plate and the vise, the light to be irradiated is directed to the surface of the vise that clamps the front end of the plate in the direction of movement. On the other hand, a printing machine characterized in that the light hits and is reflected by a part behind the notch that is farther away from the sensor.

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