JP2520149Y2 - Document shredder - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document shredder for shredding a document to be discarded, and in particular, can prevent the shredded strip from being charged with static electricity and adhering to the inner surface of a storage container. It relates to a document shredder.

[0002]

2. Description of the Related Art As shown in FIG.
A plurality of disc-shaped cutters 2 and 2 are mounted on two parallel rotating shafts 1 and 1 which rotate in opposite directions, while spacers 3 and 3 are interposed between the adjacent overlapping portions, and each of them is mounted. The cutters 2 and 2 mounted on the rotary shafts 1 and 1 are sandwiched and polymerized to form a cutter unit U, and the document 5 is drawn into the overlapped portion and vertically cut by sliding.
The strips 6 are cut laterally by the blade portions 2a of the cutter.

[0003]

Conventionally, a polymer compound such as a polyacetal resin has been used as the material for the spacers 3, 3 provided between the adjacent polymerized portions of the cutters 2, 2 in the cutter unit U. Has been. This is because many spacers having a small thickness are arranged side by side, and it is required that the spacers have excellent wear resistance and high mechanical strength. ， It is widely used in terms of quality. However, since this polyacetal resin has a large surface resistance of 10 ¹³ to 10 ¹⁴ Ω and a relatively large dielectric constant, static electricity is easily generated when the documents are shredded by the cutters 2 in a dry atmosphere. That is, static electricity is generated by sliding friction between the dried paper and the spacer. Therefore, in the case of the open type, the shredded strip 6 is charged with static electricity, and adheres to the outlet 7a of the housing 7 or the inner wall of the outlet chute 8 to get on the air flow and scatter to stain the surrounding area. Also, in the case of the closed type, the problem of scattering of the strips 6 does not occur, but as shown in FIG.
Due to the action of static electricity between the strips 6 housed in the storage container 9, the strips become piled up in the shape of a sharp mountain A and further adhere to the inner wall of the storage container 9, so that the space factor is reduced. There was a problem. An object of the present invention is to provide a document shredding machine which solves the above problems of the prior art and improves the material of the spacer so as to suppress the generation of static electricity during shredding. .

[0004]

As a concrete means for attaining the above object, the present invention provides a cutter having a blade portion on the outer periphery of each of two parallel rotating shafts which rotate in opposite directions to each other. In a document shredding machine in which spacers are arranged between the overlapping parts and are axially arranged side by side, and cutters axially mounted on the respective rotary shafts are interleaved and superposed, the spacers have surface resistance of 10 or less. We propose a document shredder characterized by being made of a material of ⁹ Ω or less.
Specific examples of the material include a polyacetal resin as a main component, a conductive resin in which carbon black is mixed, or a conductive resin in which an antistatic agent is further added.

[0005]

With the above-described means, a document put into the document shredder is cut by sliding at the cutter-nipped overlapping portion of the cutter unit and cut by the blade portion of the cutter, and cut into strips. Prevent the piece from becoming charged with static electricity.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. 2A and 2B are external views of a document shredder according to the present invention. FIG. 2A is a plan view, FIG. 2B is a side view, and FIG. 2C is a front view. The document shredder 10 has a document supply port 12 on the upper surface of the housing 7 for supplying a document to be shredded, and a cutter unit U at a position immediately below the document supply port 12.
Is provided.

The cutter unit U has a rotary shaft 1 parallel to the housing 7 as shown in FIGS.
1 so as to penetrate therethrough, a large number of disk-shaped cutters 2, 2 are mounted on each rotary shaft 1, 1, and spacers 3, 3 are alternately fitted between the adjacent overlapping portions of the cutters 2, 2. Intervene. The cutters 2 and 2 mounted on the rotary shafts 1 and 1 are sandwiched and overlapped with each other, and one ends of the rotary shafts 1 and 1 are meshed with each other by gears 13 and 13 '. The gear 14 provided at the end portion is configured to mesh with the gear 15 attached to the drive shaft 16a of the motor 16 fixed to the housing 7 so that the respective rotary shafts 1 and 1 rotate in opposite directions. There is. In addition, the cutter 2,
2 has blade portions 2a, 2a on the outer periphery that are oriented in the rotational direction, and is fixed to the rotary shafts 1, 1 to rotate integrally, but the spacers 3, 3 are protruding pieces when the rotary shafts 1, 1 rotate. 3a, 3
The a is in contact with the inner wall (P) of the housing 7 and cannot rotate.

The document 5 to be shredded is drawn into the overlapping portion of the cutters 2, 2 of the cutter unit U, cut vertically by sliding, and the cutter blade portions 2a, 2a.
Is laterally cut into strips 6. Reference numeral 11 is a separately provided chute for throwing in paper waste.

At this time, spacers 3 and 3 provided between adjacent overlapping portions of the cutters 2 and 2 in the cutter unit U.
Uses a material having a surface resistance of 10 ⁹ Ω or less. It has been proved by an experiment by the present inventor that the selection of such a material can effectively suppress the generation of static electricity when the document is shredded. A specific example of such a material is a conductive resin mainly composed of a polyacetal resin and mixed with carbon black. As an additive that imparts conductivity to the polyacetal resin, in addition to carbon black, there are metal powder, carbon fiber, etc., but these cannot exhibit the desired conductive effect with a small addition amount, and when the amount is increased, the resin originally Impair the characteristics of. Also,
It cannot be used because the surface is cooled and solidified first during injection molding, and a film layer having a low content of a conductive substance is easily formed on the surface. Carbon black does not have the above-mentioned drawbacks except when the thickness of the spacer is particularly thin,
It is a compatible additive and effective.

FIG. 4 is a cross-sectional view of a spacer formed by injection molding in which carbon black is added to a polyacetal resin. Inside the spacer 3, a carbon black having a required density is distributed from an internal conductive layer 31. Becomes
Highly conductive, but the surface is cooled during injection molding, so
The flume layer 32 having a low carbon black content is formed. In this case, when the wall thickness t of the spacer is relatively large, the surface resistance can be 10 ⁹ Ω or less only by adding carbon black to the polyacetal resin. However, when this is thin, for example, 1 to 2 mm, the injection molding is performed. , A film layer is easily formed on the surface, and the target surface resistance value cannot be achieved. Therefore, in such a case, it is more effective to use a material mainly composed of a polyacetal resin, mixed with carbon black, and further added with an antistatic agent such as a surfactant.

Since the antistatic agent is also distributed in the film layer 32 on the surface of the spacer 3, this adsorbs moisture in the air and enhances conductivity. Further, in the process of continuing the shredding by the cutter 2, the antistatic agent on this surface is worn away, but with this, the antistatic agent oozes out one after another from the layer, so-called bleed-off phenomenon occurs, The effect of addition of the antistatic agent is maintained without the conductivity of the spacer 3 being significantly lowered.

When carbon black is not added to the polyacetal resin and only the antistatic agent is added, the surface resistance of the spacer is limited to about 10 ¹⁰ to 10 ¹¹ Ω, and the antistatic effect is insufficient. To do. If an antistatic agent is applied to the surface of the spacer, the initial surface resistance may reach the target value, but if shredding is continued (several hundred sheets), the antistatic agent will be damaged due to abrasion, and Since the prevention effect is weakened, the object of the present invention cannot be achieved sufficiently.

As described above, the document shredder according to the present invention using the spacer material having a surface resistance of 10 ⁹ Ω or less, as shown in FIGS. The strip 5 is cut into small strips 6 by the cutter unit U, but at that time, the generation of static electricity is suppressed and the strips 5 do not adhere to the outlet 7a of the housing 7 or the inner wall of the outlet chute 8. Then, from the exit chute 8, FIG.
As shown in (b), the strip pieces 6 that drop toward the storage container 9 do not have the accumulated B formed into a sharp shape due to static electricity as in the conventional case, and the strip pieces 6 are attached to the inner wall of the storage container 9. They are stored in the storage container 9 in such a manner that they do not adhere to each other and sequentially overlap each other.

[0014]

As described above, in the document shredder according to the present invention, since the material of the spacer constituting the cutter unit has the surface resistance of 10 ⁹ Ω or less,
It is possible to suppress the generation of static electricity during shredding, and the shredded strips adhere to the outlet of the housing and the inner wall of the outlet chute as in the past, and in the case of the open type, they scatter on the airflow. It is possible to prevent the situation where the surroundings are polluted as much as possible. Further, in the case of the closed type, the strip pieces stored in the storage container are accumulated in a gentle shape, so that the storage amount can be increased. Furthermore, the strips in the storage container are not charged with static electricity, so they do not stick to the surrounding area when they are discarded.
There is also an incidental effect that it is easy to work.

[Brief description of drawings]

FIG. 1 is a sectional view of a cutter unit of a document shredder according to an embodiment of the present invention.

FIG. 2A is a plan view of a document shredder showing an embodiment of the present invention, FIG. 2B is a partially cutaway side view of the same, and FIG.
Similarly, it is a front view.

FIG. 3 is a plan sectional view of a cutter unit of a document shredder according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a spacer of a cutter unit used in the document shredder of the present invention.

FIG. 5 is a sectional view of a cutter unit of a conventional document shredder.

FIG. 6 is a storage state diagram of strips of a conventional document shredder.

[Explanation of symbols]

 1 rotary shaft 2 cutter 3 spacer 5 document 6 strip 7 housing 8 exit chute 9 storage container 10 document shredder U cutter unit

Claims (3)

(57) [Scope of utility model registration request] 1. A cutter having a blade portion on its outer circumference is provided on each of two parallel rotating shafts which rotate in opposite directions, and the cutters are axially arranged side by side while a spacer is provided between the adjacent overlapping portions, and are axially mounted. A document shredder in which cutters mounted on respective rotary shafts are sandwiched and polymerized with each other, wherein the spacer is made of a material having a surface resistance of 10 ⁹ Ω or less. 2. The document shredder according to claim 1, wherein the material is a conductive resin mainly composed of a polyacetal resin and carbon black mixed therein. 3. The document shredding machine according to claim 1, wherein the material is a conductive resin mainly composed of a polyacetal resin, carbon black mixed therein, and an antistatic agent added thereto.