Title:
Paper taking out device
Kind Code:
A1


Abstract:
A paper taking out device includes a rubber roller which rotates in contact with a paper medium to take out the paper medium. The rubber roller is formed of a rubber material negatively electrified by sliding with the paper medium.



Inventors:
Nishimura, Takanobu (Chigasaki-shi, JP)
Asari, Yukio (Yokohama-shi, JP)
Application Number:
11/368622
Publication Date:
01/11/2007
Filing Date:
03/07/2006
Assignee:
KABUSHIKI KAISHA TOSHIBA (Tokyo, JP)
Primary Class:
International Classes:
B65H3/06
View Patent Images:
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Primary Examiner:
MCCLAIN, GERALD
Attorney, Agent or Firm:
Pillsbury Winthrop Shaw Pittman, LLP (McLean, VA, US)
Claims:
What is claimed is:

1. A paper taking out device, comprising a rubber roller which rotates in contact with paper, thereby taking out the paper, wherein the rubber roller is formed of a rubber material negatively electrified by sliding with the paper.

2. The paper taking out device according to claim 1, wherein the rubber roller is negatively positioned in triboelectric series order with respect to the paper.

3. The paper taking out device according to claim 1, wherein the rubber roller has electric conductivity at which no corona electric discharge is generated.

4. The paper taking out device according to claim 1, comprising a powdered paper removing roller which rotates in contact with the rubber roller and is positively electrified.

5. The paper taking out device according to claim 4, wherein the powdered paper removing roller is positively positioned in triboelectric series order with respect to the rubber roller.

6. The paper taking out device according to claim 4, wherein the powdered paper removing roller is formed of an elastic material.

7. The paper taking out device according to claim 4, comprising an electrification control member brought into contact with the powdered paper removing roller to negatively electrify the rubber roller and to positively electrify the powdered paper removing roller.

8. A paper taking out device comprising: a rubber roller which rotates in contact with paper, thereby taking out the paper; and an electrification device brought into contact with the rubber roller to negatively electrify the rubber roller.

9. The paper taking out device according to claim 8, wherein the electrification device is formed of a material positively positioned in triboelectric series order with respect to the rubber roller, and is rotated in contact with the rubber roller.

10. The paper taking out device according to claim 8, wherein the electrification device is formed of a roller section and an electrically conductive brush spirally provided on an outer peripheral face of this roller section and brought into contact with the rubber roller, and is rotated together with rotation of the rubber roller.

11. The paper taking out device according to claim 8, wherein the electrification device is made of an electrically conductive member applied with high voltage electricity.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2005-183466, filed Jun. 23, 2005; and No. 2006-026797, filed Feb. 3, 2006, the entire contents of both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper taking out device provided at, for example, a mail processing apparatus or a banknote processing apparatus to take out paper such as a mail material or banknote.

2. Description of the Related Art

Conventionally, it has been well known that a paper taking out device of such type causes a rubber roller serving as a taking out roller to come into contact with collected pieces of paper, and the paper is taken out by a frictional force caused by rotation of this rubber roller, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-341860, for example.

In this paper taking out device, it is necessary to control intervals of pieces of paper to be taken out. Thus, this device receives a signal from a sensor at a downstream side of a transport passage, and must control stoppage and rotation of the taking out roller precisely at a high speed based on a transport state. In particular, in a taking out device for taking out paper by means of only a frictional force of a single taking out roller, it is mandatory that a frictional coefficient of a rubber roller with respect to paper is highly maintained as compared with a transport device or the like for pinching and transporting paper by means of a pinching force of a pair of transport rollers.

In the meantime, in the case where a large amount of pieces of paper are taken out at a high speed as in a mail processing apparatus, a friction factor may be lowered faster by some tens of times as compared with that of a rubber roller established in its left state. Occasionally, there may be established a state in which pieces of paper cannot be taken out several days after starting operation of the mail processing apparatus.

A mechanism and a condition that this phenomenon occurs have not been identified yet.

It has been considered that this phenomenon occurs due to stain caused by ink, and however, even if alcohol cleaning is carried out, a friction factor cannot be recovered. In this case, a faulty rubber roller must be replaced with its replacement roller, and there has been a problem that a replacement period becomes very short, for example, several days in the mail processing apparatus.

As described above, it is very important to maintain a friction factor of a rubber roller in a high speed frictional paper taking out device for use in a mail processing apparatus or the like. However, the deterioration of the friction factor of the rubber roller for use in taking out paper is extremely fast, and thus, there has been a problem that its replacement period is short.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention has been made in view of the above-described circumstances. It is an object of the present invention to provide a paper taking out device capable of preventing or restricting the lowering of a friction factor while clarifying a mechanism of lowering the friction factor of a taking out rubber roller.

A paper taking out device according to one aspect of the present invention comprises a rubber roller which rotates in contact with paper, thereby taking out the paper, wherein the rubber roller is formed of a rubber material negatively electrified by sliding with the paper.

A paper taking out device according to another aspect of the present invention comprises a rubber roller which rotates in contact with paper, thereby taking out the paper, and an electrification device brought into contact with the rubber roller to negatively electrify the rubber roller.

According to the present invention, reaction with ozone is restricted, and rapid oxidization deterioration of a rubber roller can be prevented, making it possible to stably and precisely take out paper.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a view adopted to illustrate an embodiment of the present invention, the view showing spectra of a result obtained by analyzing a surface layer of a rubber roller in accordance with an FT-IR analysis technique;

FIG. 2 is a graphical view depicting an electrification quantity when using a urethane rubber roller, an EPDM rubber roller, and a natural rubber roller;

FIG. 3 is a view showing a change of a dynamic friction factor of an EPDM rubber roller;

FIG. 4 is a view showing a change of a dynamic friction factor of an urethane rubber roller;

FIG. 5 is a view showing a change of a dynamic friction factor of a natural rubber roller;

FIG. 6 is a view showing a paper taking out device according to a first embodiment of the present invention;

FIG. 7 is a view showing a paper taking out device according to a second embodiment of the present invention;

FIG. 8 is a view showing a paper taking out device according to a third embodiment of the present invention;

FIG. 9 is a view showing a paper taking out device according to a fourth embodiment of the present invention;

FIG. 10 is a view showing a state in which powdered paper is deposited onto a surface of a rubber roller;

FIG. 11 is a view showing a powdered paper removing device according to the first embodiment of the present invention;

FIG. 12 is a view showing a relationship between an electrostatic electrification quantity and a sliding speed of an EPDM based rubber roller and a urethane based rubber roller;

FIG. 13 is a view showing a powdered paper removing device according to the second embodiment of the present invention;

FIG. 14 is a view showing an electrostatic electrification state of an NBR based rubber roller and a urethane based rubber roller;

FIG. 15 is a view showing a controlled electrostatic electrification state of the NBR based rubber roller and the urethane based rubber roller;

FIG. 16 is a view showing a powdered paper removing device according to the third embodiment of the present invention;

FIG. 17 is a view showing a powdered paper removing device according to the fourth embodiment of the present invention; and

FIG. 18 is a view showing a substance electrification sequence.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, a description will be given with respect to a mechanism in which there occurs a phenomenon of lowering a friction factor of a rubber roller for taking out a paper medium serving as paper identified by a recent research of the Inventor of the present application.

An EPDM rubber roller or a urethane rubber roller and the like for use in a roller for taking out a paper medium discolors more significantly and becomes more lustrous than before use. A friction factor of such a rubber roller is lowered to 60% to 80% of that before use.

FIG. 1 shows spectra of a result obtained by analyzing a surface layer of this rubber roller in accordance with a FT-IR analysis technique (Fourier transform infrared-ray spectroscopy).

In a spectrum “a” of the surface layer of the urethane rubber roller whose friction factor has been lowered, a carbonyl group clearly increases in the vicinity of a wave number from 1400 to 1500 as compared with an internal spectrum “b”. In a spectrum “c” of a rubber roller deteriorated by forced oxidization as well, a carbonyl group increases in this wave number region. This suggests that the carbonyl group increases and oxidization occurs in a rubber roller whose friction factor has been lowered.

On the other hand, in the case of a black natural rubber roller used in the same condition, the similar lowering of the friction factor does not occur, and no lustrous appearance is observed. The tendency of oxidization as described above is not observed from the FT-IR spectra of the black natural rubber roller surface layer as well.

That is, from the above investigation result, it is judged that the lowering of the friction factor of the rubber roller is due to oxidization deterioration of the surface layer.

FIG. 2 shows an electrostatic electrification quantity when using three types of the rubber rollers described previously.

In a condition in which a sliding speed is high, a urethane rubber and an EPDM rubber are positively electrified as indicated by graph lines d and e, respectively, and a natural rubber is negatively electrified as indicated by a graph line “f”. A paper medium that is a counterpart material for sliding movement is electrified with an pole opposite to that of the rubber roller.

Thus, a corona electric discharge occurs in the vicinity of a contact point between the rubber roller and the paper medium when in use. Ozone, i.e., a negative oxygen ion is refined by this corona electric discharge.

From the above observation, the mechanism of the rapid oxidization phenomenon of the rubber roller described previously is considered as follows.

On a mail material processing apparatus, the urethane rubber roller or the EPDM rubber roller repeatedly comes into contact with and separates from a mail material at a high speed. Thus, the roller electrifies a high voltage positive static electricity of some hundreds of volts to several kilovolts, and frequently generates a corona electric discharge. The oxidization of the rubber roller is rapidly accelerated by this electric discharge stimulation action for a rubber oxidization reaction.

On the other hand, in the case of the natural rubber roller negatively electrified, because of its (negative) electrification with the same pole as that of the oxygen ion, it is considered that the oxygen ion is dissociated from a surface of the natural rubber roller, and then, oxidization is restricted.

As described above, as a result of the Inventor's investigation, it has been found that rapid lowering of the friction factor of the rubber roller for taking out a paper medium is due to oxidization deterioration of the surface layer of the rubber roller, and electrostatic electrification is greatly associated with such lowering.

A preventive measure includes preventing adsorption of the oxygen ion and the stimulation action for the oxidization reaction, and includes the following methods:

(1) A material for a rubber roller is selected such that negative electrification occurs in contact with a paper medium; and

(2) A negative static electricity is forcibly electrified regardless of the material for the rubber roller to be used.

FIG. 3 is a graph plotting a measurement result of a change of a dynamic friction factor of an EPDM rubber roller sliding with a paper medium. FIG. 4 is a graph plotting a measurement result of a change of a dynamic friction factor of a urethane rubber roller sliding with a paper medium. FIG. 5 is a graph plotting a measurement result of a change of a dynamic friction factor of a natural rubber roller sliding with a paper medium.

The dynamic friction factor of the rubber roller increases with a rise of a relative speed with respect to a paper medium. Therefore, when the first paper medium which is in contact with the rubber roller is taken out by rotation of the rubber roller and a next paper medium is brought into contact with the rubber roller, the paper medium is not taken out immediately at a rotational speed of the rubber roller, but is taken out while the speed is gradually increased. That is, a sliding distance of the rubber roller with respect to the paper medium denotes a distance at which the rubber roller slides with respect to the paper medium based on a speed difference which occurs between the rotation speed of the rubber roller and a taking out speed of the paper medium.

First, a description will be given with respect to a case of using a rubber roller negatively electrified in contact with a paper medium in preventive measure (1).

FIG. 6 shows a paper medium taking out device according to a first embodiment of the present invention.

This taking out device comprises a taking out rubber roller 1 that electrifies a negative static electricity when sliding with a paper medium P, and takes out the paper medium P by a frictional force of this rubber roller 1. This rubber roller 1 is composed of a rubber material whose triboelectric series order is negatively positioned with respect to the paper medium, for example, a natural rubber.

FIG. 18 shows a triboelectric series (sequence).

The triboelectric series (sequence) frictionally rubs two types of substances with each other. Substances which are prone to be positively electrified are arranged at higher positions, and substances which are prone to be negatively electrified are arranged at lower positions. In this triboelectric series, for example, if paper and a rubber are frictionally rubbed with each other, the rubber is negatively electrified, and the paper is positively electrified. Substance electrification polarity varies depending on a counterpart to be rubbed. When the higher and lower substances in the triboelectric series are frictionally rubbed with each other, the higher positioned substance is positively electrified, and the lower positioned substance is negatively electrified. A friction between the substances whose positions are close to each other in the triboelectric series becomes comparatively small in electrification quantity.

As indicated by an electrification curve “f” in FIG. 2, it is found that a natural rubber roller is negatively electrified by sliding with a paper medium. In addition, in this natural rubber roller 1, as shown in FIG. 6, even if the roller slides with the paper medium in a state in which no electric discharge effect is attained, a phenomenon of lowering a dynamic friction factor does not occur. That is, even if a corona electric discharge occurs to generate ozone or oxygen ions, they are not adsorbed on a surface of the negatively electrified rubber roller 1. Therefore, the surface of the rubber roller 1 is not oxidized, and the lowering of the friction factor thereof can be reliably prevented.

A material for the rubber roller negatively electrified by sliding with the paper medium described above is obtained by adding electrically conductive particles such as carbon black to the rubber to slightly provide electric conductivity. Since the paper medium is positively electrified, electrostatic induction occurs, and positive static electricity is released through a core metal of the rubber roller. In this manner, the carbon black added natural rubber is negatively electrified.

In order to provide electrical conductivity to a rubber, in addition to carbon black, addition of an electrically conductive substance such as metal filler or SiC powder can be exemplified.

A small amount of carbon black is often added to an EPDM rubber. In such a rubber roller whose electric conductivity is extremely low, a difference between an accumulation speed of static electricity and a movement speed of electrification via the core metal depends on a rotation speed of the rubber roller, i.e., a frictional speed with the paper medium.

The EPDM rubber roller for use in measurement shown in FIG. 2 is negatively electrified at a sliding speed of 1.5 m/s whereas it is positively electrified at a sliding speed of 2.5 m/s. In the case where the rubber roller thus rotates at a high speed, the accumulation of static electricity becomes dominant, and static electricity is electrified at a polarity similar to that of a rubber roller that does not have electric conductivity at all.

Therefore, the rubber roller needs electric conductivity according to its use condition. It may be verified as to whether or not a material is negatively electrified by carrying out frictional electrification testing with a paper medium under a sliding condition for using the rubber roller.

Now, a description will be given with respect to a method for forcibly negatively electrifying the rubber roller in preventive measure (2).

There are the following two methods for causing the rubber roller to electrify static electricity having an arbitrary polarity:

(a) A contact type electrification roller formed of a material positively positioned in triboelectric series order is rotated in contact with the rubber roller or an electrification material is slid;

(b) An electrically conductive material applied to a high voltage electric potential is brought into contact with a rotating rubber roller.

First, the method (a) will be described with reference to FIGS. 7 and 8.

FIG. 7 shows a taking out device of a forced electrification system according to a second embodiment of the present invention.

In this second embodiment, an electrification roller 12 serving as an electrification device is brought into contact with a rubber roller 11. A material for this contact type electrification roller 12 is used as being positioned more positively than that for the rubber roller 11 in triboelectric series order.

Materials positively positioned in triboelectric series with respect to a rubber include glass, nylon, wool, silk, viscose, polyoxymethylene or the like. The rubber roller sliding with or coming into contact with these materials is stably negatively electrified. This method does not require power supply or wiring.

When an EPDM rubber roller was used as the rubber roller 11, a polyoxymethylene electrification roller was used as the electrification roller 12, and these rollers were rotated while in contact with each other at a rotational speed of 2500 mm/s, negative electrification of 0.9 KV to 1 KV was successfully stably obtained in the EPDM rubber roller. Further, in the case where a paper medium P was brought into frictional contact with the EPDM rubber roller, an electrification balance is changed, about +0.5 KV, about −1 KV, and about +0.51 W were electrified with the paper medium P, the EPDM rubber roller, and the polyoxymethylene electrification roller, respectively. As its change, stable static electricity within 0 KV to 2 KV was obtained.

FIG. 8 shows a taking out device of a forced electrification system according to a third embodiment of the present invention.

In this third embodiment, an electrification roller brush 21 serving as an electrification device are brought into contact with a rubber roller 20, and the rubber roller 20 is negatively electrified.

The electrification roller brush 21 is composed of a roller section 22 and an electrically conductive nylon brush 23 spirally mounted on an outer periphery face part of this roller section 22. This electrically conductive nylon brush 23 is brought into contact with the rubber roller 20. When the rubber roller 20 is rotationally driven, the electrification roller brush 21 rotates as a follower. In addition, the electrically conductive nylon brush 23 slides in a direction indicated by the arrow along a peripheral face of the rubber roller 20, and a frictional force works. In this manner, a surface of the rubber roller 20 is electrified by means of frictional static electricity with the electrically conductive nylon brush 23.

According to the present embodiment, there is no need for a device for applying a high voltage at the electrification roller brush side or earth, and there is no need for a rotation drive unit of the electrification roller brush, thus providing an economical electrification method.

It is preferable that a material for the brush be composed of a material whose triboelectric series order is positioned more positively than that of the rubber roller, and further, electrically conductive surface processing be applied.

Now, the method (b) will be described with reference to FIG. 9.

FIG. 9 shows a taking out device of a forced electrification system according to a fourth embodiment of the present invention.

In the present embodiment, a metal brush 32 serving as an electrification device wired to a negative pole side of a high voltage power supply 33 and applied with a direct current voltage is brought into contact with a surface layer of a rubber roller 31, and the rubber roller 31 is forcibly electrified. It is proper that a voltage of the direct current power supply 33 using this method ranges from 0.5 KV to 10 KV.

As an example, an output of the high voltage direct current power supply 33 was set to 1 KV, and a negative terminal and the metal brush 32 were wired. This metal brush 32 having a negative pole was brought into contact with an EPDM rubber roller. When the rubber roller was rotated at a rotational speed of 3000 mm/s in this state, the rubber was successfully electrified at about −0.7 KV.

According to the second to fourth embodiments described above, a rubber roller can be forcibly negatively electrified, and, even if the rubber roller comes into contact with a paper medium at a high speed rotation, an oxidization acceleration reaction caused by a corona electric discharge is restricted, and then, rapid lowering of a friction factor can be prevented.

In the meantime, at the time of frictional transport of a paper medium in each of the above described embodiments, the twisting of fibers on a surface of the paper medium is severe, powdered paper is generated in large quantity, and then, the powdered paper is deposited onto rubber rollers 1, 11, 21, and 31.

Now, by way of typical example of a rubber roller 1, a description will be given with respect to a mechanism in which powdered paper is deposited onto a surface of the roller.

FIG. 10 is an overview of the rubber roller 1 frictionally transporting a paper medium P. The rubber roller 1 is negatively electrified due to frictional static electricity between the paper medium P and a rubber, the paper medium being formed of a general cellulose fiber, and the paper medium P is positively electrified. Powdered paper 5 slips off from the paper medium P due to the friction with the rubber roller 1. At this time, static electricity of the powdered paper 5 is positively electrified, and thus, the powdered paper is deposited after being attracted by the negatively electrified rubber roller 1. As in a mail processing apparatus, in the case of high speed transport, an electrification quantity of static electricity is large, and friction is severe. Thus, a large amount of powdered paper is generated. In the rubber roller 1, a friction factor is significantly lowered due to the powdered paper 5, and taking out performance is lowered.

FIG. 11 shows a powdered paper removing device according to the first embodiment of the present invention.

In a basic configuration of this powdered paper removing device, a powdered paper removing roller 41 serving as a positively electrified powdered paper removing member is installed so as to come into rotational contact with the rubber roller 1.

Although the powdered paper 5 generated at the time of taking out a paper medium is positively electrified immediately before the powdered paper is deposited onto the rubber roller 1, when it comes into contact with the rubber roller 1, its electrification quantity is overwhelmingly small as compared with that of the rubber roller 1. Thus, the polarity of the powdered paper is negatively changed, and the powdered paper is deposited onto a surface of the rubber roller 1. The negatively electrified powdered paper 5 reaches the positively electrified powdered paper removing roller 41, the powdered paper is attracted by the powdered paper removing roller 41 in an electrostatic manner, and is released from the rubber roller 1.

It is desirable that the powdered paper removing roller 41 be formed of a soft elastic material such as a sponge or a rubber in order to voluntarily generate frictional static electricity by means of rotation in contact with the rubber roller 1. In such a material, its contact face is deformed, and thus, a microscopic slip occurs, and static electricity can be effectively generated.

In addition, with a soft elastic material, even if the rubber roller 1 is frictionally worn non-uniformly, gentle pressure is applied, thereby making it possible to maintain contact. Further, with such an elastic material containing a plasticizing agent, with respect to deposition properties with the powdered paper 5, a deposition force between materials as well as static electricity is further applied.

FIG. 12 shows a relationship between an electrostatic electrification potential and a sliding speed in the case where the rubber roller 1 is used as an EPDM based rubber roller and the powdered paper removing roller 41 is used as a urethane based rubber sponge roller.

The EPDM based rubber roller is negatively electrified, and the urethane based rubber sponge roller is positively electrified. Therefore, powdered paper can be efficiently collected by means of the powdered paper removing roller 41.

A powdered paper removing member of the present invention is not limited to the powdered paper removing roller. Even in a fixed mode such as a brush, as long as an electrostatic arrangement condition is met, powdered paper can be effectively collected in the powdered paper removing member.

In the meantime, as described in FIG. 12, the rubber roller 1 is used as an EPDM based rubber roller, and the powdered paper removing roller 41 is used as a urethane based rubber sponge roller, whereby powdered paper can be efficiently collected.

However, in a condition that the EPDM based rubber roller 1 and the urethane rubber sponge roller 41 both are negatively or positively electrified, efficient removing of the powered paper as descried above cannot be achieved. In addition, in the case where electrification of the rubber roller is close to 0 V as well, the removal of the powdered paper becomes imperfect.

TABLE 1
Effect on friction factor stability and powdered paper removal
property caused by electric conductivity of rubber roller
VolumeRubber rollerCleaner
specificelectrificationelectrificationCoronaChange ofRemoval of
resistancequantityquantityelectricfrictionpowdered
(Ωcm)(KV)(KV)dischargefactorpaper
10e5 or less    0˜−0.1−0.7˜−1.5AbsentStableDifficult
10e6˜10e9−0.2˜−0.5+0.2˜+0.5AbsentStableEasy
10e10˜10e17 −4˜−10+0.5˜+1.5AbsentStableEasy
10e18 or more−15˜−30+3.5˜+5.5PresentUnstableEasy

Table 1 shows a result obtained by investigating a powdered paper removing action by mounting the urethane rubber sponge roller 41 in the same manner as that in FIG. 11 while using a rubber roller obtained by changing the content of carbon black in an EPDM based rubber, and then, changing its volume specific resistance value.

As seen from Table 1 as well, in the case where the volume specific resistance value of the rubber roller 1 is equal to or smaller than 10e5 Ωcm, an electrification quantity of the rubber roller 1 is close to 0 V, and thus, powdered paper cannot be removed completely.

In the case where the volume specific resistance value of the rubber roller 1 ranges from 10e6 to 10e17 Ωcm, both of stability of a friction factor and powdered paper removal property were good.

In the case where the volume specific resistance value of the rubber roller 1 is equal to or greater than 10e18 Ωcm, the paper removal property was good, but because of a large electrification quantity of the rubber roller 1, a corona electric discharge occurred, and a friction factor was unstable.

Therefore, it is necessary that the volume specific resistance value of a taking out rubber roller compatible with stability of a friction factor and powdered paper removal property ranges from 10e6 to 10e17 Ωcm.

Although testing of Table 1 was carried out by using an ethylene propylene (EPDM) based rubber, similar tendency was obtained in a natural rubber (NR), a butyl rubber (IIR), or a nitryl rubber (NBR) as well.

FIG. 13 shows a powdered paper removing device according to the second embodiment of the present invention.

This powdered paper removing device is configured to be installed to come into contact with an electrification control member 45 for the purpose of controlling electrostatic electrification of the powdered paper removing roller 41.

It is mandatory that a material for the powdered paper removing roller 41 is a material positively positioned in triboelectric series order with respect to that for the rubber roller 1 and is a soft elastic material. However, electrification may not occur as desired depending on a combination with the material for the rubber roller 1.

FIG. 14 shows an electrostatic electrification state in combination of an NBR rubber roller and a urethane based removing roller. Both of them are negatively electrified, and thus, powdered paper cannot be collected by the urethane based powdered paper removing roller.

In this powdered paper removing device, there is proposed a system of controlling an electric potential electrified by bringing another material in contact with the powdered paper removing roller 41 in the case of material combination as described above.

FIG. 15 shows a state of generation of static electricity in the case where, in a combination of the above NBR rubber roller and powdered paper removing roller formed of a urethane based rubber sponge, a tetrafluoro ethylene roller serving as an electrification control member 45 is brought into contact with the powdered paper removing roller 41. This is a case in which the electrification potential of the powdered paper removing roller 41 becomes positive, making it possible to collect the powdered paper 5.

The state of generation of static electricity changes depending on a material and transport speed of the paper medium P, the rubber roller 1 and the powdered paper removing roller 41, or a sliding condition such as compression.

The electrification control member 45 is selected according to a level of the electrostatic potential of the rubber roller 1 or the powdered paper removing roller 41. Whole shifting can be achieved so that the rubber roller becomes a negative electric potential and the powdered paper removing roller 41 becomes a positive electric potential. In the case where the electrification potential of the powdered paper removing roller 41 is positively increased, a material positioned in triboelectric series order more negatively than that for the powdered paper removing roller 41 is applied to the electrification control member 45.

Conversely, in the case where the electrification potential of the powdered paper removing roller 41 is negatively lowered, there is used a material positioned in triboelectric series order more positively. For example, the materials for positively increasing the powdered paper removing roller 41 include tetrafluoro ethylene (Teflon) resin or vinyl chloride resin, a cellulose nitrate resin, a celluloid resin, and a polyethylene resin or the like. On the other hand, the materials for negatively lowering the roller include a polyamide (nylon) resin, wool, viscose, silk, and an ethyl cellulose resin or the like.

In an aspect of the electrification control member 45, as shown in FIG. 13, in the case where the member is formed in a roller shape that rotates in contact with the powdered paper removing roller 41, a sliding speed is low, and thus, there is an advantage that frictional wearing of the powdered paper removing roller 41 is small.

FIG. 16 shows a powdered paper removing device according to a third embodiment of the present invention.

This powdered paper removing device uses an electrification control plate 51 fixed as an electrification control member.

According to this powdered paper removing device, there is an advantage that large static electricity can be generated because of its low material cost and high sliding speed.

FIG. 17 shows a powdered paper removing device according to a fourth embodiment of the present invention.

This powdered paper removing device uses an electrification brush 55 as an electrification control member. According to this powdered paper removing device, it is effective to generate large static electricity and to reduce frictional wearing of the electrification control brush 55. In the case of the brush 55, this brush can additionally serve as a scraper for scraping the powdered paper 5 deposited to the powdered paper removing roller 41.

As described above, it is clarified that a main factor of the powdered paper 5 being deposited onto the rubber roller 1 is static electricity electrified with the powdered paper 5 and the rubber roller 1, and the present invention proposes a configuration for forming the rubber roller 1 and the powdered paper removing roller 41 in negative and positive arrangement as a first configuration for removing the powdered paper 5 by static electricity.

As a method for controlling arrangement of static electricity, the embodiments of the present invention propose an economical, simple configuration by way of the order on the triboelectric series of the material for the powdered paper removing roller 41 rotating together with the rubber roller 1 and a combination of materials considering a sponge material. In addition, a method for applying a direct current constant voltage is provided. With this method, there can be configured a system required for controlling a highly precise electrification state in real time in linkage with measurement of the electrification state.

A second configuration is limited if it is commercially available as an elastic material for the powdered paper removing roller 41. In the case where this elastic material is unsuitable to a combination compatible with this commercially available rubber roller material, an electrification state of each member can be controlled by bringing the electrification control member into contact therewith, thus making it possible to economically achieve an automatic powdered paper removing device according to the embodiments of the present invention.

As has been described above, according to the present invention, the powdered paper deposited to the rubber roller 1 can be cleaned efficiently and economically. Thus, maintenance of a friction factor is achieved, and operation can be made without lowering taking out performance. In addition, a powdered paper cleaning device of the present invention facilitates maintenance and enables extended time of use.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.





 
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