JPH0295854A - Paper transport device of printing machine - Google Patents

Abstract

PURPOSE:To make a position for the tip end of paper stable and increase printing accuracy by increasing the speed of paper transported by a feed roller upto the surface speed of a transfer cylinder due to the action of a cam. CONSTITUTION:Printing is started, then the tip end of paper 12 comes in contact with a front flange 23 and comes to a stop once. After this, the front flange 23 falls forward or goes upward. At that time, a cam 42 rotating in an arrow direction with a transfer cylinder 28 with a specified timing comes in contact with a roller 46. This results in the counterclockwise rotation of a lever 43 and the engagement of a rack 52 with a pinion 55, which in turn, starts the rotation of a feed roller 21 in an arrow direction. Thus the paper 12 is transported in a normal manner. The cam 42 is shaped so that when the paper 12 transported by the feed roller 21 gradually approaches the surface speed of the transfer cylinder 28 and finally reaches the same speed at the latter, the tip of the paper 12 is fed to the engagement section between the transfer cylinder 28 and an impression cylinder 25 while the obtained speed is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a paper conveying device in a printing press such as an offset printing press.

``Prior art'' For example, an offset printing machine transfers an image on a plate onto a rubber blanket, and then transfers this onto paper.
It is now ready to print.

To explain such a conventional offset printing machine with reference to FIG. 3, for example, sheets 12 placed on a paper feed tray 11 that can be raised and lowered are fed one sheet at a time from the top by the action of a vacuum-type paper feed device 13. Sent out. This sent paper 1
2 is conveyed by a feed roller 14 and a feed roller 15, and further by two sets of paper feed rollers 16 and steel balls 17.

When the leading edge of the paper 12 being conveyed passes between the feed roller 21 and the feed roller 22, which are separated in a non-rotating state, and reaches this side of the front stopper 23, the feeding roller 15 rises at this timing. At the same time, the feed roller 22 descends and comes into contact with the feed roller 21. Thereafter, the paper 12 is conveyed by two sets of paper feed rollers 16 and steel balls 17, and its leading edge abuts against the front stopper 23 and is temporarily stopped.

Lateral positioning of the paper 12 is performed by a lateral register device 24.

When the front cover 23 falls forward or escapes upward at a predetermined timing, and then the feed roller 21 begins to rotate, the paper 12 is normally conveyed, and the leading end of the paper 12 is moved toward the claw 26 of the impression cylinder 25 rotating in the direction of the arrow. is pressed against the claw stand 27 and wound around the surface of the impression cylinder 25. Printing will be performed on this rolled paper 12, which will be explained next.

The three cylinders, namely the plate cylinder 28, the transfer cylinder 29 and the impression cylinder 25, are rotated in synchronization with each other in the directions of the arrows. Plate cylinder 2
The ink applied to the printing plate (not shown) wound around the surface of the transfer cylinder 29 is transferred to the rubber blanket (not shown) wound around the surface of the transfer cylinder 29, and then the ink is applied to the rubber blanket (not shown) wound around the surface of the impression cylinder 25. The image is transferred onto the paper 12 that is being rotated, and printing is thus performed.

After printing, the leading edge of the paper 12 is released from the claw 26 of the impression cylinder 25 at a predetermined timing, and is instead moved to the claw rest by the claw 32 of the paper discharge cylinder 31, which is rotating in the direction of the arrow in synchronization with the impression cylinder 25. 33 and wound around the surface of the paper delivery cylinder 31. The leading end of the wound paper 12 is released from the claw 32 of the paper discharge cylinder 31 at a predetermined timing, and is discharged by a paper discharge belt 34 onto a paper discharge table 35 which can be raised and lowered.

By the way, in such a conventional offset printing machine, in more detail, the speed of the paper 12 conveyed by the feed roller 21 is set to be somewhat higher than the surface speed of the impression cylinder 25, and the tip thereof is rotated in the direction of the arrow. While tracing the register (not shown) of the impression cylinder 25 that is being moved and abutting it against this, it is pressed against the nail rest 27 with the claw 26, and after being wound around the surface of the impression cylinder 25, the transfer cylinder 29 and Printing is performed by passing between the printing cylinder and the impression cylinder 25.

However, since the leading edge of the paper 12 is pressed against the claw stand 27 by the claw 26 while tracking the register of the impression cylinder 25 and hitting this, it is difficult to keep the position of the leading edge of the paper 12 constant at all times. There was a problem that printing accuracy was poor.

Such problems are common in small machines, and in large machines, special equipment is used to improve printing accuracy. For example, there is a device called a swing gripper.
The tip of the paper 12, which has been stopped once in contact with the paper 12, is held in its grip by a claw and a claw base, and the paper 12 is swung to gradually bring the speed of the paper 12 closer to the surface speed of the impression cylinder 25, and when the speed becomes constant, this speed is maintained. While holding the leading edge of the paper 12, the claw 26 of the impression cylinder 25 and the claw stand 27
The paper 12 is wound around the surface of the impression cylinder 25 and transferred to the transfer cylinder 2.
9 and the impression cylinder 25 to perform printing.

However, such a conventional apparatus has a problem that it is complicated in structure, expensive, difficult to adjust, and is not suitable for small-sized machines because it increases the size of the printing machine.

In addition, in the above-described offset printing machine, the paper 12 is wound around the impression cylinder 25, so if the paper 12 is made of thick paper, it is too stiff and cannot be wound, resulting in printing problems. It will not be possible to do so.

On the other hand, in an offset printing machine that can print on thick paper, although not shown in the figure, a feed roller and a paper feed box are provided in front of the feed roller, and the paper stored in this box is fed one sheet at a time from the bottom to the rear end. The paper is sent out by being poked with a metal piece, etc., and printed by passing it horizontally between the transfer cylinder and the impression cylinder, and the printed paper is ejected to the paper ejection tray by a paper ejection belt. ing.

However, in conventional offset printing machines, the trailing edge of the paper is simply poked with a metal piece, etc., which makes it difficult to maintain the position of the leading edge of the paper at all times, resulting in poor printing accuracy. ``Problems to be Solved by the Invention'' As described above, with conventional offset printing machines, it is difficult to keep the position of the leading edge of the paper constant at all times in the case of a simple device.
It is not possible to improve the printing accuracy, and on the other hand, in the case of a complicated device, the cost is high, adjustment is difficult, and the device becomes larger, making it unsuitable for small machines.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a paper conveyance device for a printing press that can improve printing accuracy with a simple configuration.

"Means for Solving the Problem" In this invention, in a printing machine in which paper is fed between a transfer cylinder and an impression cylinder by rotation of a feed roller, and printing is performed on the paper passing between these cylinders, the feed roller After the feed roller is rotated in the forward direction through the rack and the pinion as the cam rotates, the rack is engaged with the rack, the cam is installed on the transfer cylinder or the impression cylinder, The paper conveyance device is equipped with a rotational force transmission means for rotating the paper in the opposite direction, and the speed of the paper conveyed by the feed roller increases to the surface speed of the transfer cylinder by the action of the cam. .

According to this invention, since it is only necessary to rotate the feed roller by the action of the cam, the configuration can be simplified, and the speed of the paper conveyed by the feed roller can be increased to the surface speed of the transfer cylinder. This makes it possible to stabilize the position of the leading edge of the paper and improve printing accuracy.

"Example" Hereinafter, the present invention will be described in detail with reference to Examples.

1 to 3 show the main parts of an offset printing press according to an embodiment of the present invention. In FIGS. 1 and 2, the same parts as in FIG. 3 are denoted by the same reference numerals, and the explanation thereof will be omitted as appropriate.

In this offset printing press, a cam 42 having a predetermined shape is provided at the end of a shaft 41 of the transfer cylinder 29. A lever 43 is arranged near the cam 42. The upper end of the lever 43 is rotatably attached to a machine frame (not shown) via a shaft 44. A roller 46 is rotatably provided in the center of the lever 43 via a shaft 45. The lever 43 is biased clockwise by a spring 47, but when it comes into contact with the tip of an adjustment bolt 72, which will be explained later, further rotation is prevented.

One end of a ridge 52 is rotatably attached to the lower end of the lever 43 via a shaft 51.

The rack 52 is connected to the feed roller 21 by a spring 53.
The pinion 55 provided at the end of the shaft 54 is always kept in mesh with the pinion 55. The lever 43, the roller 46, the spring 53, and the like constitute a rotational force transmitting means for rotating the feed roller 21 via the rack 52 and the pinion 55.

A lower end portion of a lever 62 is rotatably attached to a predetermined location on the machine frame via a shaft 61. The pivoting movement of the lever 62 is regulated by a pin 64 provided on the machine frame through a guide hole 63 formed in the center thereof.

A locking plate 65 is provided at a predetermined location on the lever 62. A cam 66 is arranged near the locking plate 65.

The cam 66 is rotatably attached to the machine frame via a shaft 67. A switching handle 68 is attached to the cam 66. The lever 62 is biased counterclockwise by a spring 69, but when the locking plate 65 comes into contact with the cam 66, further rotation is prevented.

Support plates 71 are provided at two predetermined locations on the lever 62. Adjustment bolts 72 for adjusting the initial position of the rollers 46 relative to the cams 42 are threaded onto these support plates 71 . The adjustment bolt 72 is locked by a lock nut 73.

This offset printing machine can perform printing in two ways. That is, when the switching handle 68 is placed in the state shown in FIG. This will be a close proximity position. On the other hand, when the switching handle 68 is in the state shown in FIG.
The lever 43 that comes into contact with the tip of the lever is in the state shown in the figure,
The normal position of the roller 46 is the shaft 41 of the cam 42.
This will be a separate position away from.

This offset printing machine starts printing in the state shown in FIG. 1 or 2, and after the leading edge of the paper 12 contacts the front cover 23 and is temporarily stopped, the front cover 23 falls forward or escapes upward. Suppose that Then, at a predetermined timing, the cam 42, which is rotating in the direction of the arrow together with the transfer cylinder 28, comes into contact with the roller 46, which causes the lever 43 to rotate counterclockwise, and by the meshing action of the rack 52 and pinion 55, the feed The roller 21 begins to rotate in the direction of the arrow, and the paper 12 is normally conveyed.

The shape of the cam 42 is such that in both the states shown in FIGS. 1 and 2, the speed of the paper 12 conveyed by the feed roller 21 gradually approaches the surface speed of the transfer cylinder 28, and when the speed becomes constant, this speed increases. The leading edge of the paper 12 can be fed into the contact area between the transfer cylinder 28 and the impression cylinder 25 while maintaining the speed. The timing at which the leading edge of the paper 12 is fed into the contact portion between the transfer cylinder 28 and the impression cylinder 25 can be precisely adjusted by adjusting the adjustment bolt 72.

Here, as already explained, the state shown in FIG. 1 and the state shown in FIG.
Since the position of the roller 46 is different from the state shown in the figure, there will be a difference in the timing at which the cam 42 contacts the roller 46. That is, for the case shown in Fig. 1,
In the state shown in FIG. 2, the timing at which the cam 42 contacts the roller 46 is delayed by a predetermined time.

Therefore, in the state shown in FIG. 2, the timing at which the feed roller 21 starts rotating is delayed by a predetermined period of time compared to the state shown in FIG. In the state shown in FIG. 1, the leading edge of the paper 12 is moved to the claw base by the claw 26 of the impression cylinder 25 rotating in the direction of the arrow.
7 and is wound around the surface of the impression cylinder 25, whereas in the state shown in FIG. This is to prevent the leading end of the paper 12 from being pressed against the nail stand 27 by the claw 26 of the impression cylinder 25.

From the above, when printing on thin paper, coated paper, etc. with this offset printing machine, it is done in the state shown in FIG. 1. That is, when the paper 12 made of thin paper, coated paper, etc. passes through the contact point between the transfer cylinder 28 and the impression cylinder 25 and protrudes a little (3 to 5 mm), its tip is pushed onto the claw rest 27 by the claw 26 of the impression cylinder 25. It is pressed down and wound around the surface of the impression cylinder 25, and printing is performed. After printing, the leading edge of the printed paper 12 is passed from the claw 26 and claw base 27 of the impression cylinder 25 to the claw 32 and claw base 33 of the paper delivery cylinder 31 at a predetermined timing. A paper discharge table 35 that is released from the claw 32 and can be raised and lowered by the paper discharge belt 34
is discharged.

On the other hand, when printing business cards, postcards, cards, etc. with this off-cent printing machine, it is done in the state shown in FIG. 2. That is, even if the paper 12 consisting of business cards, postcards, cards, etc. passes through the contact point between the transfer cylinder 28 and the impression cylinder 25 and protrudes a little (3 to 51 m), the leading end of the paper 12 is held by the claw 26 of the impression cylinder 25. It is not pressed against the table 27, but passes between the transfer cylinder 29 and the impression cylinder 25 in a horizontal state, and printing is performed. The paper 12 after printing is transferred to the impression cylinder 2
The paper is discharged onto a paper discharge table 35 which can be raised and lowered by a paper discharge belt 74 provided at the latter stage of the paper discharge table 5. At this time, the paper ejection tray 35 is
It is arranged not after the paper ejection belt 34 but after the paper ejection belt 74.

In the situation shown in Figure 2, printing on cards with gold edges that cannot be finished using Urgent after printing, items that cannot be marked with nail marks, or items that are printed from the leading edge of the paper, etc. You can also do

In the above embodiment, the cam 42 is provided on the transfer cylinder 29, but the cam 42 is not limited to this. For example, the cam 42 is provided on the impression cylinder 25.
may be provided.

"Effects of the Invention" As explained above, according to the present invention, it is only necessary to rotate the feed roller by the action of the cam, so the configuration is simple, the cost is low, and the size can be reduced, making it suitable for small machines. In addition, the speed of the paper conveyed by the feed roller can be increased to the surface speed of the transfer cylinder, so the position of the leading edge of the paper is stabilized.
It is possible to improve printing accuracy.

[Brief explanation of the drawing]

Figures 1 to 3 are shown to explain one embodiment of the present invention, of which Figure 1 is a schematic side view showing printing on thin paper, and Figure 2 is a schematic side view showing printing on thick paper. FIG. 3 is a schematic side view showing the main parts from the paper feed tray to the paper discharge tray. DESCRIPTION OF SYMBOLS 11... Paper feed table, 12... Paper, 21... Feed roller, 22... Feed roller, 23... Front stopper, 25... Impression cylinder, 26... Nail, 28...・Print cylinder, 2
9... Transfer cylinder, 31... Paper discharge cylinder, 32... Claw, 3
4... Paper discharge belt, 35... Paper discharge stand, 42... Cam, 43... Lever, 46... Roller, 47... Spring, 52... Rack, 53... Spring, 54... Pinion, 62... Lever, 66... Cam, 68...
・Handle, 69...Spring, 72...im knot holder, 74...Paper ejection belt.

Claims (1)

[Claims] In a printing machine that feeds paper between a transfer cylinder and an impression cylinder by the rotation of a feed roller, and prints on the paper that passes between them, a pinion provided on the feed roller and a rack meshed with this pinion are used. and a cam provided on the transfer cylinder or the impression cylinder, and rotational force transmission means for rotating the feed roller in the forward direction and then in the reverse direction via a rack and pinion as the cam rotates. A paper conveyance device for a printing press, characterized in that the speed of the paper conveyed by the feed roller is increased to the surface speed of the transfer cylinder by the action of the cam.