JP7519938B2 - Printer - Google Patents

Description

The present invention relates to a printing press equipped with a plate feeder device for feeding a plate to a plate cylinder provided in a printing section.

The plate feeding device of such a printing press is equipped with a transfer section for holding the plate and transferring it to the plate cylinder during the plate feeding process. The transfer section is provided with a suction pad as a holding means for holding the plate. The suction pad is connected to a vacuum pump by piping. This piping is configured with a main pipe extending from the vacuum pump, multiple branch pipes branching off from the main pipe to the suction pads of each printing unit, and a switching valve disposed on each path from the branch pipes to the suction pads. By opening this switching valve, the suction pad is connected to the vacuum pump (see, for example, Patent Document 1).

In this type of plate feeder, the vacuum pump is operated only when necessary to reduce power consumption. That is, it is operated only when the suction pad is adsorbing the plate.

In addition, vacuum pumps are sometimes installed far away from the printing press to prevent the working environment from deteriorating due to noise and heat generated during operation. In this case, the length from the main vacuum pump to the connection point to the branch pipe is increased.

Patent No. 4074119

As mentioned above, if the main pipe is long, it takes time for the pressure in the piping from the vacuum pump to the switching valve to drop to the negative pressure required to adsorb the plate. To address this, during adsorption, the switching valves provided for each printing unit are controlled to open sequentially after a predetermined time has elapsed since the vacuum pump started to operate. This predetermined time is preset according to the expected maximum length of the main pipe. Therefore, even if the vacuum pump is installed near the printing press, the above-mentioned predetermined time is required from the start of operation of the vacuum pump to the opening of the switching valve, resulting in the problem of unnecessarily long plate feeding times.

In addition, if the vacuum pump is installed so that the length of the main pipe is longer than the longest value, even after the above-mentioned specified time has elapsed, the pressure in the piping from the vacuum pump to the switching valve does not drop to the negative pressure required to adsorb the plate, and in that state the switching valve is opened and the suction pad attempts to adsorb the plate, which can result in an error in adsorbing the plate.

The present invention was made to solve these problems, and aims to provide a printing machine that can reliably adsorb plates while preventing unnecessary lengthening of plate feeding times.

In order to achieve the above object, the printing machine according to the present invention is provided with a plate feeding device for feeding a plate to a plate cylinder provided in a printing unit, and the plate feeding device is characterized by comprising: an adsorption unit that adsorbs and holds the plate to be fed to the plate cylinder; a vacuum pump; a pipe that connects the adsorption unit to the vacuum pump; a switching valve that is provided in the pipe and can be opened and closed to switch the pipe between a connected state and a non-connected state; a pressure sensor that is provided in the pipe between the switching valve and the vacuum pump and can detect the pressure in the pipe; and a control unit that executes plate adsorption control by closing the switching valve and driving the vacuum pump when a plate feeding instruction is received to supply a plate to the plate cylinder, and opening the switching valve after detecting that the pressure sensor has become equal to or lower than a first negative pressure value.

According to the above configuration, when the control unit receives a plate feeding command to feed a plate to the plate cylinder, it closes the switching valve and drives the vacuum pump, and after detecting that the pressure sensor has fallen below the first negative pressure value, it executes plate adsorption control and opens the switching valve, so that the timing to start adsorption to the adsorption unit can be optimized regardless of the distance from the printing machine to the vacuum pump. Therefore, it is possible to prevent the plate feeding time from being unnecessarily long while still ensuring that the plate is adsorbed.

In addition, in the printing machine according to the present invention, the printing section may include a plurality of printing units, and the control section may execute the plate adsorption control for each printing unit.

As described above, the control unit executes plate suction control for each printing unit, allowing the cause of suction errors to be identified quickly.

In addition, in the printing machine according to the present invention, when the control unit detects that the pressure sensor has become equal to or lower than a second negative pressure value after the switching valve is opened by executing the plate adsorption control for a specific printing unit, the control unit may execute the plate adsorption control for the next printing unit.

As described above, when the pressure sensor detects that the pressure has fallen below the second negative pressure value, plate adsorption control can be executed for the next printing unit. This allows the pressure sensor to also be used as a sensor for detecting the pressure during adsorption and determining whether the adsorption unit has successfully adsorbed the plate, thereby simplifying the device.

According to the present invention, when the pressure sensor detects that the pressure has fallen below the first negative pressure value, the switching valve opens, thereby providing a printing press that can reliably adsorb the plate while preventing the plate feed time from being unnecessarily long.

FIG. 1 is a configuration diagram of a printing machine. 1 is a schematic diagram of a plate feeding device showing a state in which a plate is set on a plate guide plate in a plate setting position. FIG. 1 is a schematic diagram of a plate feeding device showing a state in which a plate guide plate on which a plate is set has been changed into a plate feeding position; 1 is a schematic diagram of a plate feeding device showing a state in which a plate on a plate guide plate in a plate feeding attitude is positioned on a plate cylinder. FIG. 3 shows the operation of the switching valve, where (a) is in the OFF state and (b) is in the ON state. 13 is a flowchart showing a plate adsorption process of a supply plate. 8 is a flowchart showing a continuation of the process shown in FIG. 7;

The printing machine of the present invention will be described below with reference to the drawings.

As shown in Figure 1, the printing press has a paper feed section A on the upstream side and a paper discharge section B on the downstream side, with a printing section C in between that prints on the printing paper. The printing section C has four printing units, from the left, a first printing unit 1, a second printing unit 2, a third printing unit 3, and a fourth printing unit 4.

The first printing unit 1 to the fourth printing unit 4 have substantially the same configuration, so only the first printing unit 1 will be described. As shown in Figures 1 and 2, the first printing unit 1 includes a main body 10, a plate cylinder 6 that is housed in the main body 10 and on which a plate 5 is wound, a rubber blanket cylinder (also called a blanket cylinder) 7 to which ink from the plate cylinder 6 is transferred, an impression cylinder 8 that presses the printing paper against the rubber blanket cylinder 7 to transfer the ink on the rubber blanket cylinder to the printing paper, a paper feed cylinder 9 that is arranged at the front end side in the conveying direction to transfer the printing paper to the impression cylinder 8 of the printing unit 1, a transfer cylinder 11 that is arranged between the impression cylinders to transfer the printing paper from the impression cylinder of the previous printing unit to the impression cylinder of the next printing unit, an inking device (not shown) having a plurality of ink rollers that supply ink to the plate cylinder 6, and a plate feed device 12 for supplying the plate 5 to the plate cylinder 6. The plate cylinder 6 is supported rotatably on both side plates 10A, 10A of the main body cover 10 (only one side is shown in Figure 2) via a support shaft 10B.

As shown in FIG. 2, the main body 10 includes a downstream front plate 10F that is disposed downstream between the side plates 10A, 10A, and the downstream front plate 10F is attached between the side plates 10A, 10A so that it can move up and down, thereby allowing the downstream side between the side plates 10A, 10A to be opened and closed.

The plate cylinder 6 is equipped with a known clamping device 13 for holding the plate 5. The clamping device 13 is equipped with a leading edge clamping portion 13A that holds the leading edge end (lower edge in FIG. 2) 5A of the plate 5, and a trailing edge clamping portion 13B that holds the trailing edge end (upper edge in FIG. 2) 5B of the plate 5, in a pair in the circumferential direction. The leading edge clamping portion 13A is equipped with a pair of cylindrical projections 13T, 13T (see FIG. 5) that are spaced apart from each other by a predetermined distance in the axial direction (hereinafter referred to as the width direction) of the plate cylinder 6 as a positioning portion. In addition, semicircular notches 5K, 5K (see FIG. 5) that engage with the projections 13T, 13T are formed as positioning recesses in the leading edge end 5A of the plate 5. By extending the air cylinder 14 (described later), the notches 5K, 5K on the leading edge 5A of the plate 5 enter and engage the projections 13T, 13T of the plate cylinder 6, positioning both. As shown in FIG. 5, the air cylinder 14 has a cylinder tube 14B attached to a pair of support devices 26, 26 fixed to the plate guide plate 15, and a piston rod 14A with a suction pipe 22 (described later) attached to its tip.

As shown in Figures 1 to 5, the plate supply device 12 includes a suction pad 16, which is an adsorption unit that adsorbs and holds the plate 5 to be supplied to the plate cylinder 6, a pump P, a pipe 17 that connects the suction pad 16 and the pump P, a switching valve 18 that is provided in the pipe and can be opened and closed to switch the pipe 17 between a connected state and a non-connected state, a pressure sensor 19 that is provided in the pipe between the switching valve 18 and the pump P and can detect the pressure in the pipe 17, and a control unit S that controls the pump P and the switching valve 18.

Pump P is composed of a vacuum pump and is located at a position away from the printing machine. Pipe 17 includes a main pipe 171 to which vacuum pump P is connected, a pressure guiding pipe (conduit) 172 that branches off from main pipe 171 and has a smaller diameter than main pipe 171, and branch pipes 173A and 173B.

The pressure sensor 19 is provided at the top of the paper feed section A, which is located close to the pump P, and is connected to the upper end of the pressure guiding pipe 172, which is raised upward. When the control section S receives a plate feed command to supply the plate 5 to the plate cylinder 6, the pressure sensor 19 detects that the pressure in the pipe 17 has become equal to or lower than the first negative pressure value when the switching valve 18 is closed and the pump is driven for suction. The pressure sensor 19 is also configured to function as an adsorption pressure sensor that can detect that the pressure in the pipe 17 has become equal to or lower than the second negative pressure value after the switching valve 18, which is closed, is opened in the plate adsorption control described below, i.e., that the plate 5 is normally adsorbed by the suction pad 16. In more detail, when the switching valve 18 is opened, the branch pipes 173A and 173B are connected, and the pressure in the pipe 17 rises temporarily due to air leakage from the suction pad 16. However, when the suction pad 16 properly adsorbs the plate 5, air leakage from the suction pad 16 stops and the pressure in the pipe 17 drops. This drop in pressure, i.e., the pressure in the pipe 17 dropping below the second negative pressure value, is detected by the pressure sensor 19, and it can be determined that the suction pad 16 is properly adsorbing the plate 5.

The branch pipes 173A and 173B are arranged to connect the main pipe 171 to the suction pads 16 provided in each of the four printing units 1, 2, 3, and 4. One branch pipe 173A is a first branch pipe that connects the main pipe 171 to the switching valve 18 of each printing unit 1, and the other branch pipe 173B is a second branch pipe that connects the switching valve 18 to the suction pad 16.

2, the plate feeder 12 further includes a plate guide plate 15 for guiding the plate 5, and left and right air cylinders 14 as a transport unit for moving the suction pad 16 that adsorbs the plate 5 toward the clamping device 13 provided on the plate cylinder 6. The plate guide plate 15 is configured to be freely swingable by a support shaft 20 at its upper end, and is swingable by a retractable cylinder device 21 (see FIG. 5) provided on both sides of the downstream front plate 10F, so that it can be changed between a plate setting position (a position flush with the downstream front plate 10F shown in FIG. 2) in which the plate 5 is set away from the plate cylinder 6, and a plate feeding position (see FIGS. 3 and 4) in which the plate 5 is fed to the plate cylinder 6 by approaching the plate cylinder 6. Therefore, by extending and retracting the pistons 14A of the left and right air cylinders 14, the suction pipe 22 is moved in the plate feed direction, and the suction pads 16 (four in FIG. 5) attached to the suction pipe 22 move within their corresponding long holes 15A (see FIG. 5). In FIG. 5, the suction pads 16 are configured to be switchable by the extension and retraction of the air cylinders 14 between two positions: a suction position A1 (see solid lines in FIGS. 2 and 3 and FIG. 5) where the suction pads 16 are located above the long holes 15A and suction the plate 5, and a plate feed position A2 (double-dotted chain lines in FIGS. 4 and 5) where the suction pads 16 are located below the long holes 15A and on the clamp side.

When the control unit S receives a plate supply command to supply the plate 5 to the plate cylinder 6 by pressing a switch or starting an automatic program, the control unit S closes the switching valve 18 and drives the pump P for suction. When the pressure sensor 19 detects that the pressure in the piping 17 to the switching valve 18 has been reduced normally, the control unit S is configured to execute plate adsorption control to open the switching valve 18 when the pressure sensor 19 detects that the pressure in the piping 17 to the switching valve 18 is equal to or lower than the first negative pressure value. In this embodiment, since multiple printing units 1, 2, 3, and 4 are provided, the control unit S is configured to execute plate adsorption control for the next printing unit after detecting that the adsorption pressure sensor (pressure sensor 19 in this embodiment) is equal to or lower than the second negative pressure value in the plate adsorption control for a specific printing unit. In this way, the pressure sensor 19 also serves as the adsorption pressure sensor that executes the plate adsorption control for the next printing unit, thereby simplifying the device. In addition, the control unit S executes plate adsorption control for each printing unit, thereby quickly identifying the cause of an adsorption error.

As shown in FIG. 5, the suction pads 16 are arranged so that their tips protrude from each of a plurality of vertically elongated holes 15A formed at a predetermined interval in the width direction in the plate guide plate 15. The suction pads 16 are also attached to a suction pipe 22 whose base end is provided on the back side of the plate guide plate 15. A suction joint 23 is connected to the suction pipe 22 at its middle part in the width direction. A horizontal pipe 24 extending outward in the width direction is connected to the suction joint 23, and the second branch pipe 173B is connected to the outer end of the horizontal pipe 24 via a joint 25. Therefore, the joint 25, the horizontal pipe 24, the suction joint 23, and the suction pipe 22 are configured as part of the second branch pipe 173B.

Each switching valve 18 is composed of an electromagnetic valve that can be opened and closed to switch between a connected state and a non-connected state between a first branch pipe 173A connected to the main pipe 171 and a second branch pipe 173B connected to the suction pad 16. Specifically, as shown in Figures 6(a) and (b), the switching valve 18 is composed of a three-port two-position switching valve with three ports, and when energized (ON), it switches to a state in which the first branch pipe 173A and the second branch pipe 173B are connected against the biasing force of the coil spring 27 (see Figure 6(b)), and when not energized (OFF), it switches to a state in which the second branch pipe 173B is connected to the atmosphere by the biasing force of the coil spring 27 and closes the branch pipe 173A (see Figure 6(a)). As shown in FIG. 1, the second branch pipe 173B is raised upward, then guided horizontally backward, raised upward again from the rear, moved diagonally upward and forward, guided horizontally backward again, and then guided straight down, but any other guide configuration is acceptable.

The plate supply suction process will be explained based on the flowcharts in Figures 7 and 8.

When the operator presses a switch or the automatic program starts to start the plate feeding plate suction process, it is checked whether the pressure in the pipe 17 is equal to or less than the first negative pressure value (step S1). If the pressure in the pipe 17 is equal to or less than the first negative pressure value even though the vacuum pump is OFF, it is determined that the pressure sensor 19 is abnormal (step S2), and the plate feeding process is terminated abnormally. If the pressure in the pipe 17 is not equal to or less than the first negative pressure value (if it exceeds the first negative pressure value), the vacuum pump P is turned ON (step S3). In addition, the four switching valves 18 of all printing units are turned OFF (step S4). After this, it is checked whether the pressure in the pipe 17 is equal to or less than the first negative pressure value (step S5). If it is determined in step S6 that the pressure in the pipe 17 does not become equal to or less than the first negative pressure value until a certain time has elapsed, it is determined that the vacuum pump P is abnormal (step S7), and the plate feeding process is terminated abnormally. In this embodiment, it is determined in step S7 that the vacuum pump P is abnormal, but there are several possible abnormalities, such as an abnormality caused by an air leak in the piping 17 or an abnormality caused by a malfunction of the switching valve 18.

If the pressure in the pipe 17 becomes equal to or less than the first negative pressure value before the fixed time has elapsed in step S5, it is checked whether the pressure in the pipe 17 remains equal to or less than the first negative pressure value until the fixed time has elapsed (step S8). If the pressure in the pipe 17 remains equal to or less than the first negative pressure value after the fixed time has elapsed, the switching valve 18 of the first printing unit 1 is turned ON to open the switching valve 18 (step S9). This is because the pressure in the pipe 17 may be unstable, so that the pressure in the pipe 17 after the fixed time has elapsed can be checked to ensure that the process can proceed to the next step in a stable state. The fixed time in step S6 and the fixed time in step S8 may be the same, or the fixed time in step S8 may be set to a time longer than the fixed time in step S6. Step S8 may also be omitted. Next, it is checked whether the pressure in the pipe 17 becomes equal to or less than the second negative pressure value after opening the switching valve 18 (step S10). If the pressure in the pipe 17 does not fall below the second negative pressure value even after a certain period of time has elapsed, the process moves to Yes in step S11, a plate adsorption abnormality in the first unit is detected (step S12), and the plate feeding process ends abnormally.

If the pressure in the pipe 17 becomes equal to or lower than the second negative pressure value before a certain time has elapsed, it is determined that the suction pad 16 of the first unit 1 has successfully suctioned the plate 5, and the process proceeds to Yes in step S10, and the switching valve 18 of the second printing unit 2 shown in FIG. 8 is turned ON to open the switching valve 18 (step S13). After opening, it is confirmed whether the pressure in the pipe 17 becomes equal to or lower than the second negative pressure value (step S14). If the pressure in the pipe 17 does not become equal to or lower than the second negative pressure value even after a certain time has elapsed, the process proceeds to Yes in step S15, and a plate suction abnormality in the second printing unit 2 is detected (step S16), and the plate feeding process ends abnormally as shown in FIG. 7.

If the pressure in the pipe 17 becomes equal to or lower than the second negative pressure value before a certain time has elapsed, it is determined that the suction pad 16 of the second unit 1 has normally adsorbed the plate 5, and the process moves to the third printing unit 3, which is the next printing unit. Here, the third printing unit 3 operates in the same way as the second printing unit 2, so it is omitted, and the operation of the fourth printing unit 4, which is the final printing unit, is described. In the fourth printing unit 4, the switching valve 18 is turned ON to open the switching valve 18 (step S17). Then, it is confirmed whether the pressure in the pipe 17 becomes equal to or lower than the second negative pressure value (step S18). If the pressure in the pipe 17 does not become equal to or lower than the second negative pressure value even after a certain time has elapsed, the process moves to Yes in step S19, and the fourth printing unit 4, which is the final printing unit, is determined to have a plate adsorption abnormality (step S20), and the plate feeding process shown in FIG. 7 ends abnormally. If the pressure in the pipe 17 becomes equal to or lower than the second negative pressure value before the fixed time has elapsed, it is determined that the plate adsorption of all printing units 1, 2, 3, and 4 has ended normally, and the process proceeds to the next step (step S21). The second negative pressure value may be set to the same value as the first negative pressure value, or may be set to a different value. The fixed time in step S15 and the fixed time in step S19 may be set to the same time as the fixed time in step S6, or may be set to different times. It is preferable to provide a notification means (audio, display monitor, etc.) to notify the operator of the details of the abnormality when a pressure sensor abnormality, a vacuum pump abnormality, or a plate adsorption abnormality in each printing unit occurs, resulting in an abnormal end of the plate feeding process.

The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

In the above embodiment, the printing section C is composed of four printing units 1, 2, 3, and 4, but it may be composed of any number of units, such as 1, 2, 3, or 5 or more.

In addition, in the above embodiment, the plate adsorption process was performed in the order of the first printing unit 1, the second printing unit 2, the third printing unit 3, and the fourth printing unit 4, but the order is not limited to this. For example, the order may be the fourth printing unit 4, the third printing unit 3, the second printing unit 2, and the first printing unit 1, or the first printing unit 1, the third printing unit 3, the second printing unit 2, and the fourth printing unit 4.

In addition, in the above embodiment, plate adsorption control is performed for each printing unit based on the pressure detected by the pressure sensor 19 that detects the pressure inside the pipe 17, but plate adsorption control for each printing unit may also be performed based on the pressure detected by a pressure sensor provided for each printing unit.

1...first printing unit, 2...second printing unit, 3...third printing unit, 4...fourth printing unit, 5...plate, 5A...leading edge, 5B...trailing edge, 5K...notch, 6...plate cylinder, 7...rubber cylinder, 8...impression cylinder, 9...feed cylinder, 10...main body, 10A...side wall, 10B...support shaft, 10F...downstream front plate, 11...cylinder, 12...plate feed device, 13...clamp device, 13A...leading edge plate clamping portion, 13B...trailing edge plate clamping portion, 13T...projection, 14...air cylinder, 14A...piston rod, 14B...cylinder Tube, 15...plate guide plate, 15A...long hole, 16...suction pad, 17...piping, 18...switching valve, 19...pressure sensor, 20...support shaft, 21...cylinder device, 22...suction pipe, 23...suction joint, 24...side pipe, 25...joint, 26...support device, 27...coil spring, 171...main pipe, 172...pressure pipe (conduit), 173A, 173B...branch pipe, A...paper feed section, A1...suction position, A2...plate feed position, B...paper discharge section, C...printing section, P...pump (vacuum pump), S...control section

Claims (3)

a plate feeder for feeding a plate to a plate cylinder provided in the printing unit,
The plate feeding device comprises: an suction unit that suctions and holds the plate to be fed to the plate cylinder; a vacuum pump; piping that connects the suction unit to the vacuum pump; a switching valve provided in the piping that can be opened and closed to switch the piping between a connected state and a non-connected state; a pressure sensor disposed between the switching valve in the piping and the vacuum pump that can detect the pressure within the piping; and a control unit that performs plate suction control by closing the switching valve and driving the vacuum pump when receiving a plate feeding instruction to supply a plate to the plate cylinder, and opening the switching valve after detecting that the pressure sensor has fallen below a first negative pressure value. The printing machine according to claim 1, wherein the printing section includes a plurality of printing units, and the control section executes the plate adsorption control for each printing unit. The printing press according to claim 2, wherein the control unit executes the plate adsorption control for the next printing unit when it detects that the pressure sensor has become equal to or lower than a second negative pressure value after the switching valve has been opened by executing the plate adsorption control for a given printing unit.