JP2003170394A - Sheet punching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the oozed amount of oil even when an oil retaining bearing is used for a punch guide member and prevent the tip of a punch from coming out of the die and coming into contact with the peripheral edge of the opening of the die even if the punch is tilted relative to the punch guide member. <P>SOLUTION: A small diameter part 2b of a protruded part 2a is formed at the inner peripheral surface die side end part of a slide bearing 2 as the punch guide member. The small diameter part may be formed of a plurality of projected parts positioned at specified intervals in the axial direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet punching device for punching a sheet such as a sheet discharged from an image forming apparatus such as a copying machine or a printer, which sorts or stacks sheets. It can be applied to sorters, finishers, mail box devices, and the like.

[0002]

2. Description of the Related Art A sheet punching device is generally installed in an image forming apparatus and is mounted on a sorter, a finisher, a mail box device or the like for sorting and stacking sheets discharged from the image forming apparatus.

Japanese Unexamined Patent Publication No. 8-25292 and Japanese Unexamined Patent Publication No. 200
As disclosed in Japanese Unexamined Patent Publication No. 0-176895, the inner peripheral surface of the punch guide member that slidably guides the punch is a straight surface having the same inner diameter over the entire length.

FIG. 5 shows a conventional structure of a punch, a punch guide member and a die. The punch 1 is slidably guided through a cylindrical slide bearing 2 which is a punch guide member, and cooperates with a die 4 which is a hole provided in the lower guide plate 3 to form a hole in a sheet (not shown). Open up. The slide bearing 2 is press-fitted and fixed to a cylindrical boss 6 formed to project on the upper guide plate 5.

Conventionally, the inner peripheral surface of the slide bearing 2 is a straight surface having the same inner diameter over the entire length, and since the slide bearing 2 is generally composed of an oil-impregnated sintered bearing, the following problems occur. was there.

In order to secure the punching quality, that is, in order to make a clean hole, as a design target, the clearance (inner diameter difference) between the outer peripheral surface of the punch 1 and the die 4 is made as narrow and constant as possible. There is a need. For that purpose, the clearance between the outer peripheral surface of the punch 1 and the inner peripheral surface of the slide bearing 2 must be as small as possible and constant over the entire length.

[0007]

However, since it has a limit, it is inevitable that the punch 1 tilts with respect to the slide bearing 2 as shown in FIG.
When the outer peripheral surface of the punch 1 comes into contact with the upper opening edge and the lower opening edge of the slide bearing 2, the tip of the punch 1 may come off the die 4 and come into contact with the opening peripheral edge of the die 4. This often occurs when the slide bearing 2 is press-fitted into the boss 6 while being inclined, and the coaxiality between the inner peripheral surface of the slide bearing 2 and the die 4 is not ensured.

Further, the outer peripheral surface of the punch 1 and the slide bearing 2
The clearance from the inner peripheral surface of the punch is as narrow as 1 to 2 μm on one side, and when the punch 1 slides up and down during punching, oil seeps out from the slide bearing 2 which is a sintered bearing and adheres to the outer peripheral surface of the punch 1. To do. The punch 1 in this state is in a floating state like a fluid bearing. Since the oil has a viscosity, when punching, the oil film is cut off as the punch 1 slides up and down, and the sliding load increases. This sliding load is
The smaller the clearance, the larger the size.

Further, at the time of starting the punching operation or at the time of starting at a low temperature, the load is particularly large, and the transmission mechanism is destroyed, and a large mechanism and power for overcoming the load are required.

Since the number of punches and the diameter of the sheet punching device differ from country to country, the larger the number of punches and the larger the diameter, the greater the load at the time of punching at the time of start-up, and the apparatus becomes appropriate. You need a big one. By the way, in Japan 2 holes: punch hole diameter φ6, in North America 3 holes: punch hole diameter φ8,
Europe has 4 holes: punch hole diameter is φ6.

Further, since the sheet punching device is arranged at a position immediately after the sheet is discharged from the image forming apparatus at a high temperature, it punches the sheet having thermal energy.
The sheet punching device becomes hot. Under high temperature conditions, the viscosity of the oil contained in the slide bearing 2 decreases, so that the oil leaks out a lot, and the oil adhering to the outer periphery of the punch 1 adheres to the outer periphery of the hole formed in the sheet during punching. The oily sheet becomes dirty and has poor perforation quality.

On the other hand, when a general metal guide member is used as the punch guide member, there is a problem that seizure occurs and locking occurs due to vertical sliding of the punch and the punch guide member during punching.

A first object of the present invention is to reduce the amount of oil seeping out as much as possible even when the punch guide member is an oil-impregnated bearing.

A second object is to prevent the tip of the punch from coming off the die and coming into contact with the peripheral edge of the opening of the die even when the punch is inclined with respect to the punch guide member.

[0015]

The invention according to claim 1 is
In order to achieve the first object, in a sheet punching device having a punch and a die for punching a sheet and a punch guide member for guiding the punch through, at least one convex portion is provided on an inner peripheral surface of the punch guide member. It is characterized in that a small diameter part is formed.

In order to achieve the second object more effectively, the invention according to claim 2 is characterized in that the small-diameter portion is formed by a plurality of convex portions which are arranged at predetermined intervals in the axial direction. .

In order to achieve the first and second objects, the invention according to claim 3 is characterized in that the small diameter portion is formed at the die side end portion of the inner peripheral surface of the punch guide member.

The invention according to claim 4 is characterized in that a sintered oil-impregnated bearing is used as the punch guide member.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of an embodiment in which the sheet punching device according to the present invention is a two-hole punching type for domestic use, and FIG. 2 is a partial sectional view thereof.

In this sheet punching apparatus A, a horizontally elongated upper guide plate 5 and a lower guide plate 3 made of an electrogalvanized steel sheet (SECC-C material) are a gap d suitable for conveying and guiding a sheet such as a sheet. Are formed and fastened by the fastening member 7.

At both ends of the upper guide plate 5, bearing stand portions 5a bent in an L shape are formed upright, the bearings 8 are press-fitted and fixed in these U-shaped grooves, and the cam shaft 9 rotates on these bearings 8. It is freely supported.

Two eccentric cams 10 are attached and fixed to the cam shaft 9 by positioning pins (not shown), and are rotatable together with the cam shaft 9. On the outer circumference of each eccentric cam 10, a cam follower 11 is arranged so as to surround the eccentric cam 10 without play. The punch 1 made of die steel is fixed to the lower surface of each cam follower 11 by fitting its head into a groove on the cam follower 11 side.

Burring is applied to the upper surface of the upper guide plate 5, and cylindrical bosses 6 are formed at the positions corresponding to the two punches 1, respectively. The slide bearing 2, which is a copper-based sintered oil-impregnated bearing, is press-fitted and fixed to each boss 5 to a depth that secures the sheet conveyance gap a.

The lower guide plate 3 has a lower extension line coaxial with each slide bearing 2 and has a diameter of 0.0 on one side from the outer diameter of the punch 1.
The die 4 is provided by punching a hole having a large diameter of about 1 mm so that a constant clearance can be secured between the die 4 and the punch 1. The inner diameter of the slide bearing 2 is the punch 1
Slightly larger than the outer diameter of, for example, several μm on one side (1-2 μm
m) is set to be large, and the vertical sliding of the punch 1 is guided with a certain clearance secured.

A convex portion 2a is formed on the lower end of the inner peripheral surface of the slide bearing 2 by cutting or plastic working, and the inner periphery of the convex portion 2a becomes a partial small diameter portion 2b having an inner diameter d. Thus, a step is formed between the slide bearing 2 and most of the inner peripheral surface of the slide bearing 2, but the coaxiality is ensured. The inner diameter d of the small diameter portion 2b is set to be larger than the outer diameter D of the punch 1 by about 2 μm.

Next, the operation will be described. Although not shown, a one-rotation clutch is arranged on one side of the cam shaft 9 (on the right side in FIG. 1), and further, a transmission member composed of gears, a driving motor, and a control board for controlling driving are provided via a bracket. Are arranged.

The initial position of the sheet punching device A is determined by the setting position of the one-rotation clutch. Here, the eccentric position of the eccentric cam 10 is set to the upper side, and the position of the punch 1 is at the top dead center via the cam follower 11. Is held.

When the motor rotates, the sheet is conveyed by the conveying device (not shown) into the gap d between the upper and lower guide plates 5 and 3, and when a punching signal is input from the control board to the one-turn clutch, the clutch only makes one turn. It rotates and stops at its original position. As a result, the punch 1 at the position of the top dead center shown by the solid line in FIG. 2 moves to the bottom dead center shown by the chain line and then returns to the top dead center. When the punch 1 moves from the top dead center to the bottom dead center, two holes are punched in the sheet (not shown) in the gap t between the upper and lower guide plates 5 and 3.

As shown in FIG. 2, the contact area between the outer peripheral surface of the punch 1 and the small diameter portion 2b on the inner side of the slide bearing 2 is very small, and the viscous load of oil is applied only to that portion. At times, the sliding load due to the viscosity of oil is small and it can be started easily.

At a high temperature, oil seeps out from the slide bearing 2 and accumulates in the gap between the inner peripheral surface of the slide bearing 2 and the punch 1. However, since the oil is exuded by the small diameter portion 2b arranged at the lower end of the slide bearing 2, the oil is seeped out. The oil that has come out is prevented from leaking downward along the outer peripheral surface of the punch 1.

FIG. 3 is a sectional view showing the main part of another embodiment of the present invention. In this embodiment, a plurality of convex portions 2a forming a small diameter portion 2b at the lower end portion of the slide bearing 2 are provided vertically with a predetermined interval.

By providing a plurality of convex portions 2a, the effect of scraping off the oil during operation is improved, and the pressure of the applied oil is also reduced stepwise, so the effect of preventing oil leakage is great.

Since the small diameter portion 2b has a plurality of convex portions 2a,
Since the contact area between the outer peripheral surface of the punch 1 and the slide bearing 2 is small, and the viscous load of oil is applied only to that portion, the sliding load due to the viscosity of oil is small at the time of starting the device at low temperature, and it can be started easily.

At high temperature, oil seeps out from the slide bearing 2 and accumulates in the gap between the inner peripheral surface of the slide bearing 2 and the punch 1. However, a plurality of small diameter portions 2b arranged at the lower end of the slide bearing 2 seal the oil in several stages. The oil that oozes out is punch 1
It is more effectively prevented from leaking downward along the outer peripheral surface of the.

Further, in any of the above-described embodiments, as shown in FIG. 4, the small diameter portion 2b is arranged near the die 4 which is the hole of the lower guide plate 3, so that the slide bearing 2
Is pressed into the boss 6 in an inclined manner, the small diameter portion 2b of the slide bearing 2 is guided by the punch 1 even if the coaxiality between the inner peripheral surface of the slide bearing 2 and the die 4 cannot be obtained to some extent. Since the punch 1 is arranged closer to the center, a gap is provided at the tip of the punch 1 with respect to the inner peripheral surface with the die 4.
Therefore, the tip of the punch 1 does not come into contact with the die 4, and damage to the punch tip blade due to the punching operation is avoided.

In the above embodiment, the slide bearing 2
The cross-sectional shape of the small-diameter portion 2b is made circular according to the punch 1, but the shape is not limited to circular, and shapes other than circular, for example, oval, square,
It may be triangular. Further, although the present invention is applied to the two-hole punching type sheet punching device, the number of holes is not limited.

[0038]

In the sheet punching device according to the first aspect of the invention, since the sliding surface area between the punch and the punch guide member (slide bearing) is small, the sliding load can be reduced.
The sheet punching driving force at the time of start-up at low temperature can be small, and the apparatus can be made compact. In addition, it is possible to drive with a small amount of power, the generated noise is small, and the cost of the device is low.

When used under high temperature, when the oil permeates from the punch guide member (slide bearing), the small diameter portion of the punch guide member ensures a seal with the punch. There is no contamination and the perforation quality is ensured.

In the sheet punching device according to the second aspect of the invention, the small diameter portion of the punch guide member is formed by a plurality of convex portions that are axially spaced at predetermined intervals, so that the sealing performance at that portion is remarkably high. It improves the oil bleeding prevention effect.

In the sheet punching device according to the third aspect of the present invention, the small diameter portion is formed at the die side end portion of the inner peripheral surface of the punch guide member so that the swinging of the punch is performed between the lower portion of the cam follower and the punch guide member. Since it is prevented at the tip of the die side, that is, it is performed at a distant position, the vertical vertical sliding of the punch can be stably performed.

Further, even if the coaxiality between the inner peripheral surface of the punch guide member and the die is not obtained to some extent,
Since the small diameter portion of the punch guide member is arranged closer to the center portion, a clearance is provided between the tip of the punch and the inner peripheral surface of the die. Therefore, a margin for processing can be obtained, so that it is possible to obtain a device that is easy to stably manufacture and has good drilling quality.

In the sheet punching device according to the fourth aspect, by using the oil impregnated sintered oil-impregnated bearing as the punch guide member, oil is constantly supplied to the punch, and seizure due to oil shortage is eliminated. By increasing the sintering density of the powder metallurgy, the oil retaining property of the oil is secured, and by using the oil of high viscosity, the effect of exuding the oil at high temperature can be enhanced.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment in which the present invention is applied to a two-hole punching type sheet punching device.

FIG. 2 is an enlarged cross-sectional view of a main part thereof.

FIG. 3 is an enlarged sectional view of another embodiment of the present invention.

FIG. 4 is a sectional view of the operation of the present invention.

FIG. 5 is a cross-sectional view showing a structure of a conventional punch, a punch guide member, and a die.

FIG. 6 is a sectional view of the operation.

[Explanation of symbols]

1 punch 2 Slide bearing 2a convex part 2b small diameter part 3 Lower guide plate 4 die 5 Upper guide plate 5a Bearing base 6 Boss 7 fastening members 8 bearings 9 cam shaft 10 eccentric cam 11 cam followers

Claims (4)

[Claims] 1. A sheet punching device having a punch and a die for punching a hole in a sheet and a punch guide member for guiding the punch through, wherein a small diameter portion formed by at least one convex portion is provided on an inner peripheral surface of the punch guide member. A sheet punching device characterized by being formed. 2. The sheet punching device according to claim 1, wherein the small-diameter portion is formed by a plurality of convex portions that are arranged at predetermined intervals in the axial direction. 3. The sheet punching device according to claim 1, wherein the small diameter portion is formed at an end portion of the inner peripheral surface of the punch guide member on the die side. 4. The sheet punching device according to claim 1, wherein a sintered oil-impregnated bearing is used as the punch guide member.