JPS6365581B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION To the present invention, there is a method for horizontally controlling the uppermost layer of sheets stacked in a stacked manner in a feeder portion of a sheet-fed offset printing machine (hereinafter also simply referred to as a sheet-fed printing machine). This invention relates to a method and device for leveling stacked sheets of paper.

As is well known, sheets used in sheet-fed printing are stacked in a stack on a pile board in a feeder section of a sheet-fed printing machine, and are sequentially fed to a printing section starting with the top layer of sheets. These sheets, especially sheets that have been left after printing on one side, are likely to have paper curls. When printing on sheets with paper curls, if you stack them as is on a pile board, the top surface of the stacked sheets (stacked sheets) may partially bulge and become flat. Therefore, it is extremely difficult to smoothly feed the paper from the feeder to the printing section.

For this reason, conventionally, when printing again, the operator would fold the sheets to create creases, or insert a stack of uncurled correction paper between the stacked sheets, etc. to avoid paper distortion. After removing the pile plate and leveling the top surface of the stacked sheets, the pile board is raised one pitch at a time and sequentially fed to the printing section.

Paper texture after single-sided printing tends to take three forms, as shown in FIGS. 1a to 1c. That is, Figure a shows an example in which the leading edge 2 and trailing edge 3 on the supply side of the stacked sheets 1 are lowered, and Figure b shows an example in which only the trailing edge 3 lowers.
Figure c shows an example in which only the front edge 2 is lowered. Then, when this stacked sheet 1 is turned over for printing on the back side, as shown in FIGS. 2 a to c, respectively,
The front and rear edges, rear edge, and front edge are warped and raised.

By the way, even when it is said that paper curls occur, the amount of swelling is emphasized in stacked sheets 1, which are stacked in large numbers, ranging from several thousand to 10,000 sheets.
If you look at each piece, the amount of excitement is insignificant.
Therefore, even if the sheets have curls when stacked, as long as the top surface of the stack is flat, the sheets can be fed smoothly from the feeder to the printing section.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method and apparatus for leveling the top surface of stacked sheets so that even sheets with curls can be reliably fed from a feeder to a printing section. In particular, the purpose is to eliminate the work of removing paper curls, which has traditionally been done manually and has low work efficiency.

In order to achieve such an object, the present invention detects the height of each area of the upper surface of the top layer of sheets of stacked sheets arranged in the feeder section of a sheet-fed printing press,
Based on this information, a plurality of lifting devices arranged on the pile board and supporting the stacked sheets are controlled to lift the lowered stacked sheet area and level the top surface. It is something that
The present invention will be explained below with reference to Examples.

3 to 7 are diagrams showing a leveling device for stacked sheets of paper according to an embodiment of the present invention, in which FIG. 3 is a perspective view showing an outline of the leveling device, and FIG. 4a, b
5 is a schematic front view showing the feeder section incorporating the leveling device, and FIG. 6 is a schematic perspective view of the lifting device for lifting the stacked sheets of paper. , FIG. 7 is a hydraulic circuit diagram of a lifting device in the same leveling device.

The leveling device 4 in this embodiment, as shown in FIG. A box-shaped support 7 on which the leaflet 1 is placed on a flat top surface, and a plurality of lifting devices 8 comprising a cylinder mechanism disposed inside the support 7.
and a detector 9 for detecting the height of each area on the upper surface of the stacked sheets 1, that is, the upper surface of the uppermost sheet. The support stand 7 has a rectangular bottom plate 11 larger than the size of the sheet 10, and this bottom plate 11.
It consists of a bottom plate 11 supported by legs 12 vertically disposed at four corners of the frame, and an upper plate 13 having the same dimensions and having a flat upper surface. Furthermore, 24 cylinder mechanisms 14 arranged in 6 rows and 4 columns are arranged on the bottom plate 11, and the rods 15 that protrude by hydraulic pressure are directed upward. A support plate 16 made of a rectangular plate is fixed to the tip of each rod 15. In addition, the upper plate 13
There is a support plate 16 for the elevating part of each cylinder mechanism 14.
A hole 17 through which the cylinder mechanism 14 can pass is provided corresponding to each cylinder mechanism 14. Further, as shown in FIG. 7, each cylinder mechanism 14 is operated by switching the three-position switching valve 18, so that the rod 15 can be raised or lowered by a desired distance. Support plate 1
To lock the height of the valve 6, the switching valve 18 may be placed in the neutral position. In addition, to prevent movement of the rod 15 due to leakage in the neutral position, pilot operated check valves 19, 2 are installed to ensure sealing under high pressure.
0 into the hydraulic circuit. Further, each of the outer support plates 16 is located inward from the outer peripheral edge of the sheet 10. Therefore, as shown in FIG. 4a, when the front and rear edges 2, 3 of the stacked sheets 1 are warped upward, the cylinder mechanism 14 is operated to raise the support plate 16 a desired distance. , the upper surface of the stacked sheets 1, that is, the upper surface of the uppermost layer of sheets to be fed out, is made horizontal as shown in FIG. 4b. Note that even if the leading edge or the trailing edge is curved and protrudes, the upper surface of the stacked sheets can be leveled in the same way. In addition, although there are few cases, when the back side is turned over to print, the result is as shown in Figure 1 a, b, and c. In these cases, the cylinder mechanism 14 is operated in the same way as in other cases, and the top side is printed. Leveling is achieved.

On the other hand, the detector 9 consists of six pairs of projectors 21 and receivers 22, each of which is attached to a frame 23 disposed so as to surround the outer periphery of the upper edge of the stacked sheets 1 of the feeder section 5. It is being
That is, each pair of light emitters and receivers 21 and 22 is located on a line corresponding to each row of the cylinder mechanism 14 group, and depending on whether or not the light flux running between the pair of light emitters and receivers 21 and 22 is blocked, the bar stacking is performed. It is detected whether each area on the upper surface of the sheet 1 (in this case, a strip-shaped area of 6 lines) reaches a certain height. Therefore, in this embodiment, the switching valves 1 of the six cylinder mechanisms 14 in each row are
8 is controlled based on information from each pair of light projector/receiver 21, 22 corresponding thereto.

On the other hand, the pile board 6 is controlled to rise and fall by a lifting device 24 as shown in FIG. That is, the pile board 6 is supported by the crossbars 25 on both lower surfaces. Both ends of the two crossbars 25 are supported in a hooked state by pins 27 provided on four vertically installed endless chains 26. The endless chain 26 is driven by a worm 29 and a worm gear 30 that transmit the forward and reverse rotations of the electric motor 28, and is raised by forward rotation and lowered by reverse rotation.

Next, a method for leveling the upper surface of stacked sheets will be explained. First, the sheet 10 that has been printed on one side is inverted and placed on the support stand 7 on the pile board 6 with the surface to be printed facing upward.
As shown in Figure a, the pile board 6 is raised to a height that allows sheet feeding.

Then, the detector 9 automatically operates to detect the upper surface of the stacked sheets 1, that is, the downwardly facing part of the top surface of the top layer sheet, and transfer the light beams received by each light receiver 22 to the stacked sheets. The cylinder mechanism 14 is operated to the height at which it is interrupted by the upper surface of the sheet 1, and the fourth
As shown in figure b, the top sheet is straightened horizontally. When leveling is achieved, the feeder unit sequentially feeds the sheets one by one from above to the printing unit. Furthermore, if the horizontality of the top surface of the stacked sheets changes,
The detector 9 automatically detects the change and controls the raising and lowering of the corresponding cylinder mechanism (lifting device 8) 14. As a result, since the top surface of the stacked sheets can always be leveled, the sheets can be fed accurately and stably.

Note that the present invention is not limited to the above-mentioned embodiments, and modifications thereof are possible based on the technical idea of the present invention. For example, there may be a greater number of cylinder mechanisms, and each peripheral portion of the sheet may also be supported by a support plate to achieve more fine leveling. In addition, if the sheet rises not at the front and rear edges but at the left and right side edges, a pair of light emitters and receivers should be provided in each column direction of the cylinder mechanism. The columns may also be made to operate in unison. Further, as the detector, other general sensors such as a capacitance displacement meter and an air micro sensor may be used.

Furthermore, as shown in FIG.
By placing and using the pallet 33 provided with
It becomes possible to shorten the down time of the printing press and improve the operating rate.

As described above, according to the present invention, even if there is paper curl, the top layer of sheets in a stack of sheets can always be leveled, so that sheets can be accurately and reliably transferred from the feeder section to the printing section. can be sent out, and the operation rate of the sheet-fed printing press can be improved.

Further, according to the present invention, there is no need for a complicated work of removing paper curls, so that the number of man-hours can be reduced.

For this reason, according to the present invention, printing costs can also be reduced.

[Brief explanation of drawings]

1a to 1c are perspective views showing stacked sheets after single-sided printing, 2a to 2c are perspective views of the same reversed state, and 3a and 3b are perspective views of a leveling device according to an embodiment of the present invention. A perspective view, FIGS. 4a and 4b are sectional views showing the state before and after the leveling operation, FIG. 5 is a schematic front view showing the feeder section incorporating the leveling device, and FIG. 6 is the same as the leveling device. FIG. 7 is a hydraulic circuit diagram of a lifting device in the leveling device, and FIG. 8 is a sectional view showing a leveling device according to another embodiment. DESCRIPTION OF SYMBOLS 1... Sheet stack on a stick, 2... Leading edge part, 3... Trailing edge part, 4... Leveling device, 5... Feeder part,
6... Pile board, 7... Support stand, 8... Lifting device, 9... Detector, 13... Top plate, 14... Cylinder mechanism, 16... Support plate, 17... Hole, 1
8...Switching valve, 21...Light emitter, 22...Light receiver, 24...Elevating device.

Claims (1)

[Scope of Claims] 1. Detecting the height of the upper surface area of the topmost sheet of a stack placed on a support stand provided with a plurality of lifting devices, and detecting the height of the upper surface area of the top sheet of the stack that corresponds to the lowered part. A method for leveling stacked sheets of paper, characterized in that the bottom portion is lifted by the lifting device to bring the top layer of sheets into a horizontal state. 2 A plurality of lifting devices equipped with support plates that can protrude and retract from the surface of the support are arranged vertically and horizontally inside the stacked sheet support stand, and the stacked sheets placed on the support stand are arranged vertically and horizontally. 1. A leveling device for stacked sheets of paper, characterized in that a detection device is provided to detect the height of each region of the uppermost layer of paper, and each lifting device is controlled based on information from the detection device. 3. A stacked sheet support stand equipped with multiple lifting devices inside is installed on a pile board that is controlled to rise and fall, and the height of each area of the top layer is set at a height position where sheets can be fed. A leveling device for stacked sheets of paper according to claim 2, further comprising a detection device for detecting the same.