JPH03219955A - Sheet decurler - Google Patents

Abstract

PURPOSE:To prevent a wasteful air suction from suction holes to ensure the suction force of the suction holes sucking sheet paper by mounting a means for closing the suction holes disposed out of the width of the passing sheet paper from inside a sheet decurler bar. CONSTITUTION:When printing is made on sheet paper 2 of a width less than the length of a sheet decurler bar 4 that is determined in accordance with a maximum printable width, air is sucked from suction holes 6 disposed outside the sheet paper 2 because of the absence of an object to be sucked. This air reduces the suction force of suction holes 6 sucking the sheet paper 2. Then, closing sheets 8 of Teflon or the like are disposed on the rear of the suction holes 6 each correspondingly to the suction holes 6 that are divided into groups in accordance with the widths of the sheet paper 2. On positions in the absence of the sheet paper 2, the suction holes are closed with the closing sheets 8 from below in place of the sheet paper 2 from above. In this manner, a wasteful air suction from the suction holes 6 with the sheet paper 2 absent is prevented, and the suction force of the suction holes 6 sucking the sheet paper 2 is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet decurler for a sheet-fed printing press, and in particular to means for optimally setting holes for sucking sheets of paper according to the width of the paper. It is something.

[Conventional technology]

In general, in printing machines, curls often occur on paper after printing, with the printed surface facing outward. When curling occurs in this way, the filter paper will not be aligned properly at the paper output section, causing paper wrinkles, paper flaws on the printed surface, and ink transfer. Must. Furthermore, the printing speed is also limited, making it impossible to fully utilize the capabilities of the machine.

[Problem to be solved by the invention]

In order to solve these problems, a decurrer rubber with suction holes formed at predetermined intervals in the longitudinal direction is placed near the paper output section of a sheet-fed printing machine, and this decurrer rubber is evacuated by a vacuum pump to print the sheet-fed paper. A sheet decurler has been proposed and used that removes curls from a sheet by passing the uncurled side of the paper through a decurler rubber while adsorbing it.

The position and number of suction holes in conventional sheet decal rubber are as follows:
It is determined according to the maximum paper width that can be printed on that printing machine. Therefore, when sheets of paper with a small width come in, suction holes appear that do not allow the sheets to pass through. Since the suction holes through which the sheets do not pass are open, a large amount of air is sucked in through these holes, which reduces the suction power of the decurler rubber as a whole, which adsorbs the sheets, and prevents the decurler from being sufficiently efficient. There was a problem with not being able to perform.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet decurler equipped with means for blocking unnecessary air flow from suction holes in accordance with the paper width of the sheet.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention disposes a decal rubber having suction holes formed at predetermined intervals in the longitudinal direction near the paper discharge section of a sheet-fed printing machine and evacuates it with a vacuum pump to print the sheet-fed paper. In a sheet decurler that removes curls from sheets by passing the uncurled side of the paper while adsorbing it to the decurrer rubber, means for closing suction holes located outside the width of the sheet through which the sheets pass from inside the decurrer rubber. This paper proposes a sheet decurler equipped with the following functions.

Specifically, the blocking means includes a flexible sheet arranged corresponding to the suction hole divided according to the type of paper width of the sheet, and a flexible sheet that is arranged to correspond to the suction hole divided according to the type of paper width of the sheet. It consists of a pushing mechanism.

The blocking means also includes a shutter plate formed in a step-like shape with an outer side close to the suction hole corresponding to each suction hole divided according to the type of paper width of the sheet, and this stepped shutter plate. The suction hole may be configured to have a mechanism in which the suction hole is moved forward or backward along the sheet passing direction to face the divided suction holes.

In either case, it is possible to operate the closing means manually, but a sensor that detects the passage of a sheet and outputs a drive command signal to the flexible sheet drive mechanism or the step-like shutter removal drive mechanism is installed at the paper width. It is desirable to provide the sheet decurler at a position on the inlet side of the sheet decurler corresponding to each section.

Instead of the sensor that detects the passage width of the sheet.

It is also possible to use a sensor which is adjusted to the paper width of the sheet to be printed and detects the position of the filter board.

[Effect]

The present invention is equipped with a means for closing the suction holes located outside the sheet passage width from the inside of the sheet decurler rubber, so that there is no need to suck in wasteful air from those suction holes. The suction power of the suction holes that adsorb the paper is ensured.

Furthermore, the shape and size of the suction hole can be optimally designed, and in this sense, the suction force is also increased.

In addition, if a sensor that detects the passage of a sheet and outputs a drive designation signal to the sheet moving mechanism is installed at a position on the entrance side of the sheet decurler corresponding to each paper width division, the closing means can be set according to the paper width. can be operated automatically,
No manpower is required.

In place of the sensor that detects the passing width of the sheet, when using a sensor that detects the position of the paper gathering board that is adjusted to the paper width of the sheet to be printed, the closing means may be adjusted according to the paper width. It can be operated automatically, eliminating the need for human intervention.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view (A) and a side sectional view (B) showing a basic embodiment of the present invention. In the figure, the sheet decurler rubber 4 on which the sheet 2 passes is provided with two rows of suction holes 6 formed at predetermined intervals along its suction surface. The inside of the sheet decal rubber 4 is evacuated using a vacuum pump (not shown), and the sheet 2 is transferred to the sheet decal rubber 4 through the suction hole 6.
This is to avoid curling of the sheet 2 that occurs during printing.

However, when printing a sheet 2 whose width is shorter than the length of the sheet decal rubber 4 whose length is determined according to the maximum printable width, from the suction hole 6 on the outside of the sheet 2,
Air is sucked in because there is nothing to be absorbed. This air reduces the suction force of the suction holes 6 that suction the sheet 2.

Therefore, in this embodiment, Teflon, etc. are placed on the back side of the suction holes 6, corresponding to the suction holes 6 that are divided according to the paper width of the sheet 2 (in this case, two from the outside). A closing sheet 8 consisting of the following is arranged, and at positions where the sheet 2 does not come, the closing sheet 8 is arranged to close the suction hole from the bottom surface instead of the sheet 2 on the top surface.

By doing this, there is no need to suck in wasteful air from the suction hole 6 where the sheet 2 does not come. The suction force of the suction hole 6 that suctions the sheet 2 is ensured. Further, the shape and size of the suction hole 6 can be optimally designed, and in this sense, the effect of increasing the suction force can be obtained.

A more specific mechanism for steadily bringing the closing sheet 8 in the position where the sheet 2 does not come into close contact with the sheet decurrer rubber 4 will be explained with reference to FIG. 2. The center of the closing sheet 8 is fixed to the sheet decal rubber top plate 4A. The closing sheet 8 further receives a downward force from a spring 12, and is guided by a cam rocker arm guide 14, so as to be in contact with the upper end of a rocker arm 10 which is movable up and down. When the cam 16 is pulled by the plunger 20 against the force of the return spring 18, the rocker arm 10 pushes up the closing sheet 8 toward the suction hole 6 of the sheet decal rubber 4.

Although the plunger 20 may be operated manually after confirming the width of the sheet 2, it is preferable to operate the plunger 20 automatically in accordance with the width of the sheet 2. The means for this purpose will be explained with reference to FIG. Here, reflective photoelectric sensors 22 are installed on the side of the sheet decurler rubber 4 from which the sheets 2 flow, corresponding to the divisions of the suction holes 6. The photoelectric sensor 22 is turned ON when the sheet 2 is not detected.
It turns off when sheet 2 is detected. Therefore, at a position where the sheet 2 does not come, the photoelectric sensor 22
outputs an ON signal to the plunger 20, and the plunger 20
is operated to bring the closing sheet 8 close to the sheet decal rubber-top plate 4A from the back side to ensure suction.

Another embodiment of the present invention will be described with reference to FIG.

In this embodiment, a blockage sheet 28 is formed on a staircase whose outer side is close to the suction hole 6, and a stepped blockage sheet 28 corresponds to the suction hole 6 divided according to the paper width of the sheet 2. It consists of a mechanism for moving the paper sheet 2 forward or backward along the passing direction of the sheet 2 to face the divided suction holes 6. The drive mechanism includes a motor or handle 30, a steel wire 32, a pulley 34, and a seat guide 36.

As is clear from FIG. 5 shown in more detail, the drive mechanism further includes a position detection sensor 38 for detecting whether the closing sheet 28 has returned to its original position, and a motor or handle 3o for each step of the staircase. It includes a cam 40 that detects the corresponding rotational position and a microswitch 42 that is operated by this cam 40.

Basically, this embodiment can also be operated manually by operating a handle, but here, a method will be described in which the width of the sheet 2 is detected and the closing sheet 28 is automatically set.

FIG. 6 is a diagram illustrating the installation situation of the photoelectric sensor 22. In this case, as in Fig. 3, the sheet decal rubber 4
A reflective photoelectric sensor 22 is installed on the side from which the sheets 2 flow, corresponding to the divisions of the suction holes 6. Photoelectric sensor 2
2 is turned ON when the sheet 2 is not detected, and turned OFF when the sheet 2 is detected.

An example of a control circuit for driving the motor 30 in response to signals obtained from the photoelectric sensor 22, the position detection sensor 38, and the microswitch 42 to set the closing sheet 28 at the optimum position will be described with reference to FIG. In the figure, if the closing sheet 28 is not in the original position when the start switch 50 is pressed, the output of the position detection sensor 38 is OF.
Since the signal is F, the AND gate G3 sets the flip-flop FF3 by the signal inverted by the inverter INVI. Flip-flop FF3 connects AND gate G1 via OR gates OR2 and OR3.
Then, the relay K is operated to forcibly reverse the motor 30 and bring the closing sheet 28 to its original position. When the closing sheet 28 comes to the original position, the position detection sensor 38 turns on.
Therefore, AND gate G3 turns OFF, but AND gate G4 turns ON this time, and flip-flop FF3
to be reset. The signal from the position detection sensor 38 is
At the same time, counter C is reset to zero. Note that when the start switch 50 is pressed, if the closing sheet 28 is in the original position from the beginning, the AND gate G4 is turned off.
The situation is the same after becoming N.

The signal from the sensor 22 for detecting the paper width of the sheet 2 enters each decoder D, and as a coded signal B,
Input to comparator COM.

On the other hand, the signal A from the counter C is also applied to the comparator C.
Input to OM. Comparator COM outputs A and B
, and the signals corresponding to A>B, A<B, and A=B are input to monostable multivibrators MMI, MM2 .
Output to AND gate G2.

Now, since the counter C has been reset by the operation of setting the closing sheet 28 to its original position, the output A of the counter C is zero. Here, if the paper width detection photoelectric sensor 22 detects one area where the sheet 2 does not come and is turned ON, the output B of the decoder D becomes 1. A comparator COM that compares the two determines that A<B, sends a signal to the monostable multivibrator MM2, resets the flip-flop FFI, and sets the relay K to the forward rotation side. The signal from monostable multivibrator MM2 also simultaneously sets flip-flop FF2 via OR gate ORI. flip flop F
When F2 is set, a signal is issued from the AND gate G2 to open the gate of the AND gate G1 through the OR gate OR3, and power is supplied to the motor 30 to rotate it in the forward direction.

At the same time, the signal of A<B of comparator COM is
Start counting up counter C.

When the motor 30 rotates and the motor position detection microswitch 42 operates, a pulse is input to the counter C and the count A is set to 1. Now, the input of the comparator COM becomes A=B, a corresponding signal is output, AND gates G2 and G1 are closed, and the motor 30 is stopped.

At the same time, the signal from microswitch 42 resets flip-flop FF2 to return to its initial state.

When two or more photoelectric sensors 22 are operating, the above operation is continued until the comparator COM determines a match.

When the paper width increases and the number of operating photoelectric sensors decreases, the output of comparator COM becomes A>B, monostable multivibrator MMI operates, flip-flop FFI is set, and relay K is activated. At the same time as setting the counter C to the reverse side, the DOWN terminal of the counter C is opened. Furthermore, the monostable multivibrator MM1 sets the flip-flop FF2 via the OR gate OR1,
Reverse the motor 30. The position detection pulse of the motor 30 causes the count of the counter C to decrease, and the operation continues until A:B.

In this embodiment as well, there is no need to suck in wasteful air from the suction holes 6 to which the sheets 2 do not come, and the suction force of the suction holes 6 that suction the sheets 2 is ensured. In addition, the shape and size of the suction hole can be optimally designed, and in this sense, the effect of increasing the suction force can be obtained.

In particular, a simple control circuit can automatically detect the paper width of a sheet and close the suction hole where a sheet does not come, which saves manpower.

Fig. 8 is a side view (A) and a front view (B) showing an embodiment in which the width of the paper stacking plate for properly aligning the printed paper in the paper discharge section is detected and the suction holes of the sheet decurler are automatically closed.
). The printed paper 2 is carried by a paper discharge chain 64 having a paper gripping bar 60 and driven by a sprocket 62, and is successively stacked on a paper receiving plate 66 in a paper discharge section of the printing machine. In order to align the printed paper 2 properly,
A front cover and a paper gathering board 68 (not shown) are used.

Among them, the paper collecting plate 68 is attached to a square bar 72 that is slidably supported by the paper discharge section frame 70. Square bar 7
2 slides with respect to the paper discharge unit frame 70, and can change the width between the paper stacking plates 68 in the left and right direction in FIG. 8(B). In this embodiment, a dog 74 fixed to a prism 72 is used.
The width between the paper shifting plates 68 is detected by a combination of the magnetic encoder 76 and the magnetic encoder 76.

When a series of printing operations is completed and the next lot is to be printed, the width between the left and right paper shifting plates 68 is adjusted to the aW of the paper 2 to be printed first, and the left and right positions of the paper 2 are regulated. . In reality, the paper alignment plate 68 is slightly vibrated to increase the paper alignment effect.

In this embodiment for detecting the position of the paper gathering board 68, for example, the closing sheet 28 of the decal rubber 4 of the embodiment of FIG. Able to move to position immediately.

Although an example using the magnetic encoder 76 has been described here, it is also possible to use a limit switch, a proximity switch, or the like.

〔Effect of the invention〕

According to the present invention, since there is provided a means for closing suction holes located outside the passage width of a sheet of paper from inside the sheet decal rubber, there is no need to suck in wasteful air from those suction holes. The suction power of the suction hole that suctions the sheet is ensured.

Furthermore, the shape and size of the suction hole can be optimally designed, and in this sense, the suction force is also increased.

Furthermore, if a sensor that detects the passage of a sheet and outputs a frame movement command signal to the sheet drive mechanism is installed at the entrance side of the sheet decurler corresponding to each paper width division, the closing means can be set according to the paper width. It can be operated automatically, eliminating the need for human intervention.

In place of the sensor that detects the passing width of the sheet, when using a sensor that detects the position of the paper gathering board that is adjusted to the paper width of the sheet to be printed, the closing means can be automatically adjusted according to the paper width. It can be operated automatically, and no human labor is required.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a basic embodiment of the present invention, FIG. 2 is a diagram showing a more specific mechanism for steadily adhering a closed sheet in a position where a sheet does not come to a sheet decal rubber, and FIG. 3
The figure shows a means for automatically operating the plunger according to the paper width of the sheet, FIG. 4 shows another embodiment of the present invention, and FIG. 5 shows the drive mechanism of the embodiment shown in FIG. 6 is a diagram showing the installation situation of the photoelectric sensor 22, and FIG. 7 is a diagram showing an example of a control circuit for setting the closing sheet of the embodiment in FIG. 4 to the optimum position. FIG. 8 is a diagram showing an embodiment in which the width of the paper stacking plate for properly aligning printed papers in the paper discharge section is detected and the suction holes of the sheet decurler are automatically closed. 2...Sheet paper, 4...Decal rubber, 6...Suction hole 8...Closing sheet, 10...Rocker arm, 1
2... Spring, 14... Cam/rocker arm guide, 16... Cam, 18... Return spring, 20... Plunger, 22... Photoelectric sensor,
28... Closed sheet, 30... Motor or handle, 32... Steel wire, 34... Pulley, 3
6... Sheet guide, 38... Position detection sensor, 4
0... Position detection cam, 42... Micro switch, 50... Start switch, 6o... Paper gripping bar 62... Sprocket, 64... Paper ejection chain, 6
6... Paper receiving plate, 68... Paper collecting plate, 70... Paper discharge section frame, 72... Square column, 74... Dog, 76
...Magnetic encoder.

Claims (1)

[Claims] 1. A decal rubber having suction holes formed at predetermined intervals in the longitudinal direction is placed on the paper passage path of a sheet-fed printing machine, and is evacuated by a vacuum pump so that the paper surface of the sheet is absorbed by the decal rubber. A sheet decurler that removes curls from the sheets of paper as they pass through the decurler, characterized by comprising means for closing the suction holes located outside the width of passage of the sheets from inside the decurler rubber. Sheet decal. 2. The sheet decurler according to claim 1, wherein the closing means includes a flexible sheet arranged corresponding to the suction hole, which is divided according to the type of paper width of the sheet; A sheet decurler comprising: a mechanism for pushing toward the divided suction holes. 3. In the sheet decurler according to claim 1, the closing means is formed in a step-like shape with an outer side close to the suction hole corresponding to each of the suction holes divided according to the type of paper width of the sheet. 1. A sheet decurler comprising: a stepped shutter plate; and a mechanism for moving the stepped shutter plate forward or backward along the sheet passage direction to face the divided suction holes. 4. In the sheet decurler according to any one of claims 1 to 3, a sensor detects passage of the sheet and outputs a drive command signal to the flexible sheet drive mechanism or the stepped shutter plate drive mechanism. are provided at positions on the entrance side of the sheet decurler corresponding to the paper width divisions. 5. The sheet decurler according to any one of claims 1 to 3, wherein the means for outputting a drive command signal to the flexible sheet drive mechanism or the stepped shutter plate drive mechanism is configured to output a drive command signal to the sheet to be printed. A sheet decurler characterized in that it is a sensor that detects the position of a paper shuffling plate that is adjusted to a paper width of .