JPH0513540U - Document shredder - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to a document shredder that can shred documents to be discarded and prevent falling strips from being charged with static electricity and adhering to the inner surface of a storage container. [Structure] A cutter having a blade portion on the outer circumference is provided on each of two parallel rotating shafts that rotate in opposite directions, while a spacer is provided between the adjacent overlapping portions, and the cutters are mounted side by side in the axial direction. In a document shredding machine in which cutters mounted on the rotating shaft of n are interleaved and polymerized, the spacer is mainly made of a material having a surface resistance of 10 ⁹ Ω or less, for example, polyacetal resin, and carbon black is mixed therein. A document shredding machine characterized by comprising the conductive resin described above or a conductive resin further containing an antistatic agent.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a document shredder for shredding discarded documents, and more particularly to a document shredder that can prevent a situation in which shredded strips adhere to the inner surface of a storage container due to static electricity. is there.

[0002]

[Prior Art]

 As shown in FIG. 5, the document shredder 10 includes disk-shaped cutters 2 and 2 on two parallel rotating shafts 1 and 1 which rotate in opposite directions to each other, and a spacer 3 between the adjacent overlapping portions. , 3 are interposed, and the cutters 2 and 2 mounted on the respective rotary shafts 1 and 1 are interleaved and polymerized to form a cutter unit U, and the document 5 is attached to the overlapped portion. Is drawn in and cut vertically by sliding, and cut horizontally by the blade portions 2a, 2a of the cutter to form strip pieces 6.

[0003]

[Problems to be solved by the device]

Conventionally, a polymer compound such as a polyacetal resin has been used as a material for the spacers 3, 3 provided between the adjacent polymerized portions of the cutters 2, 2 in the cutter unit U. This is because many spacers with 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 and 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 and the inner wall of the outlet chute 8 to get on the airflow and scatter to contaminate the surrounding area. .. Further, in the case of the closed type, the problem of scattering of the strips 6 does not occur, but as shown in FIG. 6, the strips 6 are housed in the storage container 9 and the strips are sharpened by the action of static electricity. There is a problem that the space factor becomes small because it becomes a mountain-shaped accumulation A and further adheres to the inner wall of the storage container 9. It is an object of the present invention to solve the above problems of the prior art and to provide a document shredding machine capable of suppressing the generation of static electricity during shredding by improving the material of the spacer. ..

[0004]

[Means for Solving the Problems]

As a specific means for achieving the above object, the present invention provides a cutter having a blade portion on the outer circumference of each of two parallel rotating shafts that rotate in opposite directions, and a spacer interposed between the adjacent overlapping portions. On the other hand, in a document shredding machine in which the cutters mounted side by side in the axial direction are mounted and the cutters mounted on the respective rotary shafts are sandwiched and superposed, the spacers are made of a material having a surface resistance of 10 ⁹ Ω or less. It proposes a document shredder characterized by the above. 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]

[Action]

 By the above means, the document input to the document shredder is cut by sliding at the cutter insertion overlapping part of the cutter unit, and when cut by the cutter blade part, the shredded strip pieces are Prevents from being charged with static electricity.

[0006]

【Example】

 Embodiments of the present invention will be described below in detail 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 for supplying a document to be shredded on the upper surface of the housing 7, and a cutter unit U at a position immediately below the document supply port 12.

As shown in an enlarged view in FIGS. 1 and 3, the cutter unit U penetrates through rotary shafts 1, 1 parallel to the housing 7, and each rotary shaft 1, 1 has a disk-shaped cutter 2, A large number of 2 are vertically mounted, and spacers 3 are alternately inserted between the adjacent overlapping portions of the cutters 2 and 2. 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 the gears 13 and 13 '. The gear 14 provided at the other end meshes 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, 1 rotate in opposite directions. ing. The cutters 2 and 2 have blade portions 2a and 2a on the outer circumference that are oriented in the rotational direction, and are fixed to the rotating shafts 1 and 1 to rotate integrally. During the rotation of 1, the protruding pieces 3a, 3a come into contact with the inner wall (P) of the housing 7 so that they cannot rotate.

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

At this time, the spacers 3 and 3 provided between the adjacent overlapping portions of the cutters 2 and 2 in the cutter unit U are made of a material having a surface resistance of 10 ⁹ Ω or less. It has been proved by experiments by the present inventor that by selecting such a material, it is possible to effectively suppress the generation of static electricity during document shredding. A specific example of such a material is a conductive resin mainly composed of a polyacetal resin and mixed with carbon black. In addition to carbon black, there are metal powders, carbon fibers, etc. as additives that impart conductivity to the polyacetal resin. The original characteristics are impaired. Further, the surface is cooled during injection molding and solidifies first, and a film layer having a low content of a conductive substance is likely to be formed on the surface, and therefore cannot be used. Carbon black is an additive which is compatible with the above-mentioned drawbacks and is effective, except when the spacer is particularly thin.

FIG. 4 is a cross-sectional view when a spacer is formed by injection molding in which carbon black is added to a polyacetal resin. The inside of the spacer 3 is an internal conductive layer in which carbon black having a required density is distributed. Although it has a high conductivity, the surface is cooled during the injection molding, so that 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 reduced to 10 ⁹ Ω or less only by adding carbon black to the polyacetal resin, but when this is thin, for example, 1 to 2 mm, injection molding is possible. At times, 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, and with this, the antistatic agent oozes out from the layer one after another, so-called bleed-off phenomenon occurs. Therefore, the conductivity of the spacer 3 is not significantly lowered, and the effect of adding the antistatic agent is maintained.

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 wear, Since the antistatic effect is weakened, the object of the present invention cannot be achieved sufficiently.

As described above, the document shredding machine according to the present invention using the spacer material having a surface resistance of 10 ⁹ Ω or less, as shown in FIGS. 1 to 3, is a document to be shredded. 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 are not attached to the outlet 7a of the housing 7 or the inner wall of the outlet chute 8. Then, as shown in FIG. 2 (b), the strip pieces 6 falling from the outlet chute 8 toward the storage container 9 are such that the accumulated B has a sharper shape due to static electricity as in the conventional case. Without being attached to the inner wall of the storage container 9, the sheets are sequentially stored in the storage container 9 in a state of overlapping.

[0014]

[Effect of the device]

As described above, in the document shredding machine according to the present invention, the material of the spacer constituting the cutter unit has the surface resistance of 10 ⁹ Ω or less, so that the generation of static electricity during shredding is suppressed. The strips can be adhered 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, the situation of riding on the air current and scattering to contaminate the surroundings. It can be prevented 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, since the strips in the storage container are not charged with static electricity, they do not adhere to the surrounding area when they are discarded, which has the additional effect of facilitating 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.

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)

[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 that rotate in opposite directions, and the cutters are lined up in the axial direction while a spacer is provided between the adjacent overlapping portions, and the cutter is mounted. A document shredder in which cutters mounted on respective rotary shafts are sandwiched and polymerized, and 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 polyacetal resin and carbon black mixed therein. 3. The document shredder 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.