JPH01261138A - Device and belt for transporting sheet of paper - Google Patents

Abstract

PURPOSE:To provide stable running of a sheet of paper by forming a transcript belt from a dielectric substance, having a volume resistivity of the dielectric substance layer over a specific value and a surface resistivity over a specific value, and a conductor having corresponding values under a specific value. CONSTITUTION:A transcript belt of a transcript sheet transport device is formed from a dielectric substance, having a volume resistivity of the dielectric substance layer of dielectric substance 1 over 10<12>OMEGA.cm and a surface resistivity over 10<12>OMEGA/hole, and a conductor 4 having corresponding values under 10<6>OMEGA.cm. That is, charges on the belt dielectric substance 1 are prevented from passing through the dielectric substance and decreasing by giving the belt 10 a volume resistivity over 10<12>OMEGA.cm. Transcript sheet 28 is attracted strongly to the belt 10 by maintaining high electric charge sufficiently while the injection charges on the transcript sheet 28 with electric resistance decreased due to moistening are refrained from neutralizing with the surface charges of the belt dielectric substance 1 by giving the belt dielectric substance 1 a surface resistivity over 10<12>OMEGA/hole.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a paper material conveying belt and a paper material conveying device for supporting and conveying sheet-like or long paper materials in copying machines, printers, and other devices.

Conventional technology An example of a transfer/conveyance device consisting of two layers of dielectric and conductive material used in copying machines is disclosed in Japanese Patent Application Laid-Open No. 56-154772.
It is shown in the publication No.

FIG. 6 shows an outline of the above transfer/conveyance device.

Next, the operation of this device will be explained. The transfer/conveyance bell) 10 is composed of a dielectric material on the surface that contacts the transfer paper material 28 or the photoreceptor 21, and a conductive material on the surface that contacts the support rollers 22, 23, and 24. The transfer/transport belt 10 is stretched by the support roller, and is moved in the direction of the arrow in synchronization with the circumferential speed and direction of rotation of the photoreceptor 21 via one of the rollers by a drive source (not shown). Driven.

An electrostatic latent image forming means (not shown) forms an electrostatic latent image on the surface of the photoreceptor, and a developing means (also not shown) forms a charged toner image on the photoreceptor. It reaches a contact portion with a transfer/transport belt (hereinafter referred to as belt) 10. Transfer/transport belt (hereinafter referred to as belt)
The 10 conductive surfaces are grounded via the roller 22, and the dielectric surface of the 0th bell is in contact with a conductive brush 26 to which a voltage is applied by a DC power source 27. When the belt IO is driven, the belt dielectric surface is charged to the same polarity as the applied voltage by sliding with the conductive brush. The polarity of the toner charge is opposite to that of the belt. The transfer paper material 28 is fed onto the belt from the right side in the figure in synchronization with the belt running. The transfer paper material is sandwiched between the photoreceptor 21 and the belt 10, and the above-described developed image on the photoreceptor is transferred to the transfer paper material by an electric field formed by charges on the dielectric surface of the belt. The transfer paper material 28 is peeled off from the belt surface by the relatively small curvature of the belt support roller 23 and the rigidity of the transfer paper material. The toner on the photoreceptor may be transferred onto the belt due to a timing lag between the supply of the transfer paper material and development, or a failure in the supply of the transfer paper material, etc.
By providing a cleaning blade and a backup roll 24 that supports the cleaning blade from the back, toner on the belt is removed, charging is performed again, and the above steps are repeated.

Transfer/transport belt materials include belts made from polyester film on which aluminum is vapor-deposited as a conductor, and conductive rubber belts with a core bar inserted into a dielectric material solution using the so-called dipping method. Examples include belts formed with The specific resistance of the dielectric is 106Ω・1 or more, and the specific resistance of the conductor is 106
The following is considered a suitable range.

FIG. 5 shows a transfer/paper material conveying device which is provided in contact with the belt and has means for injecting electric charge into the transfer paper material in contrast to the above-described device. When the transfer paper material passes between the left belt of the charge injection means, charges of opposite polarity to those on the belt are injected into the transfer paper material, so that the transfer paper material is strongly attracted by Coulomb force. Next, the toner reaches the contact portion between the belt and the photoreceptor and is transferred to the transfer paper material. Therefore, the transfer performance of the transfer paper material is better than that of the transfer/conveyance device shown in Fig. 6, and there is less paper wrapping around the photoreceptor and jamming, and the transfer material is transported suspended as shown in Fig. 5. You can also.

Problems to be Solved by the Invention As mentioned above, the transfer/conveyance device shown in FIG. Even though the electrical properties of the belt meet the above conditions, depending on the material of the dielectric material of the belt and the humidity environment, the suction force of the copy paper that has absorbed moisture to the belt decreases, and the transfer material peels off from the belt. There were many cases where it could not be carried into the fixing device.

Means for Solving the Problems In the transfer belt in the transfer/paper material conveyance device of the present invention,
In order to solve the above problems, the belt has a dielectric layer with a volume resistivity of 10 IzΩ·1 or more and a surface resistivity of 10
Dielectric of 697 or more and 106Ω.

It is composed of a conductor with a diameter of cm or less.

action The operation of the above technical means will be explained.

That is, by setting the volume resistivity of the belt to the above value, the charge on the belt dielectric is prevented from passing through the dielectric and decreasing, and the surface resistivity of the belt dielectric is set to the above value. As a result, the transfer paper material is strongly attracted to the belt by maintaining a sufficiently high charge without neutralizing the injected charge of the transfer paper material whose electrical resistance has decreased due to absorption of moisture and the surface charge of the belt dielectric material.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the basic cross-sectional configuration of the transfer/paper material conveyance belt of the present invention. In the figure, dielectric l is conductor 2
are integrally combined with. If the adhesion between the dielectric layer 2 and the conductor is poor, an adhesive layer 3 may be interposed between the dielectric layer 2 and the conductor as shown in FIG. When the adhesive layer is insulating, the total of the dielectric layer and the adhesive layer becomes the dielectric. When the adhesive layer is electrically conductive, it acts as part of the electrical conductor. or,
As shown in FIG. 3, a dielectric surface layer 5 made of a material with excellent lubricity or a material with excellent wear resistance is added to the surface of the dielectric layer in order to improve the belt's cleaning performance and wear resistance against cleaning. You can.

An example of a belt configuration is shown below. An elastomer resin conductor with a thickness of 0.1 to 1.5 mm, made conductive by adding carbon to the conductor, a polyester tube dielectric with a surface dielectric having a thickness of 30 μm and no seams, and between the conductor and the dielectric. The belt has a circumferential length of 380 fl and a width of 315 N.

This belt was cut into 1cIII width, electrodes were placed on the conductor surface with a 10cm space, and the resistance was measured with a digital electronic meter to determine the volume resistivity.
The resistance was 106Ω. In addition, the resistance in the thickness direction of this belt was determined by applying a voltage of 100 V and applying a voltage of 30 V using the method shown in FIG.
The resistance after a few seconds was measured, and the volume resistivity of the dielectric was found to be 10 6 Ω·cm or more, assuming that the resistance of the conductor portion was sufficiently small. Furthermore, the surface resistance of this belt was determined from the resistance after 30 seconds with an applied voltage of 100 V using the method shown in FIG. 10, and was found to be 10'4 Ω/□ or more. Note that to measure the surface resistance, it is necessary to confirm with a surface potential meter that there is no charge on the dielectric surface. If the charge is large, an error will occur in the measured value. In Figures 9 and 10, 51 is 50m
The mφ electrode 52 is a ring-shaped guard electrode with an inner diameter of 701-φ, and is an electrode defined in JIS. 50 is a TR-8601&fi edge resistance meter manufactured by Atopan Test Co., Ltd.

FIG. 5 shows a transfer/paper material conveyance device using the above belt. In the figure, bell number 0 with dielectric on the outside is stretched and suspended by support rollers 22,23. At least one of the support rollers is electrically conductive, and the electrical conductor inside the belt is grounded through this electrically conductive support roller. The belt is driven at 12 (hm/sec) in the direction of the arrow in the figure with one of the support rollers connected to power.

The belt is charged to +1600 V by a charger 31 and is driven in contact with charge injection means consisting of a grounded conductive roller provided opposite to the support roller 22. The photoreceptor 21 rotates in synchronization with the running of the belt, is positively charged by a charger (not shown), and is electrostatically charged on the photoreceptor by an exposure device (not shown) using a laser diode. A latent image is formed, and the latent image is reversely developed using negatively charged toner by a developing means (not shown). In synchronization with the exposure of the photoreceptor, the transfer paper material 28 is sandwiched between the belt and the charge injection means 33 and sent to the belt surface, and the transfer paper material is injected with a charge opposite to the charge on the belt from the charge injection means. It gets sucked into the belt. In Fig. 5, the charge injection means has a structure in which the conductor in contact with the belt is directly grounded, but it is also possible to insert charge injection regulating means such as a resistance element or a voltage generation source between the conductor and the ground. You may. The transfer paper material reaches the contact portion between the belt and the photoreceptor, and the toner on the photoreceptor is transferred onto the transfer material by an electric field generated by the charges on the belt. When transcribing,
The electric field formed by the belt is offset to some extent by the opposite charge of the transfer paper material. However, in reality, even if the charge injection means is directly grounded, it will not be completely canceled out.

If there is a problem with the transfer, the above-mentioned injection charge regulating means can be provided. The transfer paper material remains attracted to the belt and reaches the support roller 23, where it is peeled off from the belt due to the small curvature of the belt and the rigidity of the transfer material, and reaches a fixing device (not shown), where the transferred toner is fixed on the transfer paper material. and ejected from the aircraft. Further, toner transferred onto the belt due to out of synchronization between the photoreceptor running and the belt running, leakage of transfer paper material, etc., is removed from the belt surface by the cleaning means 32.

The above transfer/paper material conveyance device was heated at 33°C, 8o% R, H.

(R” indicates relative humidity) and 20”C
160% R, H, (7) exposed to the environment, 33℃, 8o
%R,H, in an environment of 33℃ and 80%R,H for more than a day and night, the volume resistivity becomes IXl010Ω・
When a transfer/conveyance test was carried out using plain paper for a copying machine with a diameter of 1.5 cm, the paper was strongly attracted to the belt and conveyed, and good toner transfer was obtained.

For comparison, we will discuss a belt with a low dielectric surface resistance and transfer/conveyance tests using it.

The already mentioned conductor has a thickness of 0.1 tm and the dielectric has a thickness of 30 tm.
A belt made of a μm polyester film and a 30 μm hot-melt adhesive is suspended between two metal support rollers.
One of the support rollers is grounded, and a corona charger and a grounded conductive brush are provided around the suspended belt for static elimination, and the belt is heated to 1600 V to 200 V.
Rotate at 0 V for various times.

By repeatedly charging and neutralizing the dielectric material of the belt, the surface is altered by ozone and ion bombardment generated by the corona charger. According to the electrical property measurement method described above, the volume resistivity of the dielectric material of these belts at room temperature (20°C, 60% R, H) and 33°C, 80% R, H, is 101SΩ・on the mouth surface, The volume resistivity of the conductor is 2×103
Met. The surface resistivity of dielectrics is all IQ at room temperature.
I! It was Ω・1 or more. These belts were attached to the above-mentioned transfer/paper material conveyance device, and a transfer/conveyance test was conducted using paper that had been left in an environment of 33° C. and 80% R/H to become damp. In an environment at room temperature, the suction force of the paper to the belt was sufficient, and the transfer density was also sufficient. However, 3
In an environment of 3° C. and 80% R and H, there were cases where the belt conveyed the paper normally, but the paper sometimes peeled off from the belt before reaching the normal peeling position. When the surface resistivity of the belt was measured in an environment of 33° C. and 80% R, H, the results shown in Figure 1) were obtained. From this result, it can be seen that the surface resistivity of the belt on the edge is required to be 1012 Ω in order for the wet paper to be normally fed.

In the transfer/paper material conveying device of the present invention, the retention of charge on the belt, which is closely related to the attraction force of the transfer material to the belt, will be described.

The belt is electrically charged by the belt charger 31 of FIG. 5, at least at the contact area between the photoreceptor and the belt, and is sufficiently maintained until the transfer paper material leaves the belt. The volume resistivity of the body layer must be sufficiently high. The minimum required volume resistivity is determined by the time T0 required for the belt to travel from the belt charging position to the transfer paper material peeling position. That is, when calculated using a mathematical formula, the result is as follows.

The volume resistivity of the dielectric is ρ [Ω・cffi], and the thickness is d [
C1)], the area is s (oJ), the relative permittivity is 1, and the permittivity of vacuum is ko, then the capacitance between the thicknesses is C=kkOS/dThe electrical resistance between the thicknesses is R=ρd It can be expressed as /S.

Therefore, the time constant is T=CR=ρkk.

The permittivity of vacuum is ko = 8.84XIO-14(F/
e1)). Let the dielectric constant of the organic compound be 3.

If the initial potential is vo and the potential after seconds is V, then I n
There is a relationship of (V/Vo)=-t/kkop.

Assuming the process speed and belt running system of a normal copying machine, To should be at least 0.5 seconds. When the volume resistivity of the dielectric material of the belt is IQIIΩ・Bi, the charging potential of the belt is 15% of the original value, and when the volume resistivity of the dielectric material of the belt is 106Ω・Bi, the charging potential of the belt is 8% of the original value.
It will be 3%. Therefore, the volume resistivity of the dielectric is 1012Ω・
If it is 1 or more, the attenuation of the charged potential of the belt at the contact portion with the photoreceptor and further at the position where the transfer material is peeled from the belt can withstand the toner transfer and the attraction of the transfer paper material to the belt in practical use.

The surface resistance of the dielectric material of the belt is greatly related to the attraction force of the transfer paper material to the belt. FIG. 7 shows the state of charges on the belt and transfer paper material after charges are injected by the charge injection means. As shown in FIG. 8, the transfer paper material and the belt should naturally be in point contact. As mentioned above, the surface charges on the transfer paper material and the belt have opposite polarities and are attracted to each other by Coulomb force. If both the surface resistance of the belt and the resistance of the transfer paper material are low, the charges will move and be neutralized through the point contact portions and will be reduced, and the attraction force of the transfer material to the belt will be reduced. The volume resistivity of plain paper as a transfer paper material is approximately 106°Ω·Ω when left in an environment of 33° C. and 80% R, H, which is an environmental condition that can be encountered. Even when the transfer paper material is not in contact with the belt and the volume resistivity of the belt is high and there is no attenuation of the charged charge, the surface resistivity of the belt is low.As mentioned earlier, the surface charge of the belt and the charge of the paper are As a result, the suction force of the paper to the belt decreases. In order to obtain a practical paper suction force and transfer rate even for paper whose resistivity has decreased due to moisture absorption, the surface resistivity of the belt must be 10.
It needs to be 12Ω・0 or more.

Also, speaking of the volume resistivity of the conductor, it is 106Ω
-cm or less is suitable. When the belt is charged with a charger, if it is initially charged to a predetermined voltage and then there is no leakage through the dielectric, the current flowing from the belt to ground is extremely small, so the IR effect is small, but the actual In the transfer/paper material conveying device of the invention, when the paper is not being conveyed, the electric charge on the belt is less likely to escape to the ground by the electric charge injection means. While the transfer paper material is being conveyed, when the transfer material is separated from the belt, a discharge occurs between the charges on the belt and the charges on the transfer material, so that the charge on the belt decreases.

Since the above-mentioned reduction in the charge on the belt differs depending on the presence or absence of the transfer paper material, the current flowing from the ground to the belt conductor changes to charge the belt.

If the resistance of the conductor is high, the voltage drop between the belt's charger position and the ground will fluctuate greatly, and as a result, the amount of charge on the belt will not be constant over time, resulting in changes in the density of the transferred image. From this point of view, in the transfer method of the present invention, it is preferable that the volume resistivity of the conductor is 106Ω below the mouth plate.

Some additional information will be given regarding the configuration and belt of the transfer/paper material conveyance device of the present invention.

In the figure, the charge injection means has a configuration in which the conductive roller is grounded, but the conductive roller may be grounded by intervening a means for regulating charge injection, such as a resistor or a power supply, or the conductive roller material may be grounded. can be made of metal, rubber, plastics, etc. Thermosetting and thermoplastic organic materials are suitable as the main material for the belt because of their excellent processability. The conductive layer is made of a material containing a conductive material such as carbon, graphite, or metal powder in addition to the above-mentioned materials.

An example of making a belt will be described. A thermoplastic polyester or other elastomer resin tube containing fine carbon powder is heated and extruded into a tube shape, and the tube is attached to a cylindrical core metal that has been treated with mold release properties. A hot-melt adhesive resin film is added to the surface of the cigarette, and then a polyester or other thermoplastic tube is attached as the outer surface layer, which is then heated and shrunk to integrate it, and then removed from the core and cut and shaped at both ends. . Seamless thermoplastic heat-shrinkable tubes are made by heating and melting the plastic and extruding it into a mold with an annular slit.The raw tube is then inserted into the mold and the tube is It can be made by keeping both ends airtight, applying internal pressure, heating to a temperature above the softening point, expanding, and then cooling.

In the embodiment, a paper material conveyance device in a laser beam printer using electrophotographic technology has been described, but the present invention is not limited to this, and can be applied to general paper material conveyance using an electrostatic adsorption method.

Effects of the Invention As described above, the paper material of the present invention has a dielectric material having a volume resistivity of 10 12 Ω/value or more, a surface resistivity of 10 6 Ω/4 or more, and a conductor having a volume resistivity of 10 6 Ω/4. The conveying belt of the conveying device has excellent charge retention and exhibits stable charging properties, and the paper conveying device using this belt and means for injecting electric charge into the paper material allows the paper material to run stably. Furthermore, in the copying machine and printer equipped with this conveyance device,
Reduces jams and improves reliability.

[Brief explanation of the drawing]

1, 2, and 3 are cross-sectional configuration diagrams of a paper conveyance belt according to the present invention, FIG. 4 is a perspective view of a paper conveyance belt according to the present invention, and FIG. 5 is a paper conveyance apparatus according to the present invention. FIG. 6 is a side view of a conventional transfer device, FIG. 7 is an explanatory diagram illustrating the charge state of the belt and transfer paper material in the present invention, and FIG. 8 is a side view of the belt and transfer paper material in the present invention. Fig. 9 is an explanatory diagram showing a method for measuring the volume resistance of the dielectric material of the belt;
Figure O is an explanatory diagram showing a method of measuring the surface resistance of the dielectric material of the belt, and Figure 1) is an explanatory diagram showing the relationship between the surface resistivity of the belt dielectric material and paper conveyance. 1...Dielectric material, 2...Dielectric layer, 3...
...Adhesive layer, 4...Conductor, lO...
...Transfer/paper material conveyance belt, 21...Photoreceptor,
28... Transfer paper material, 31... Charger,
32...Charge injection means. Name of agent: Patent attorney Toshio Nakao, 1 person!・-Electric body Figure 2 03 Figure 5- Electric body table ff74 Figure 4 Figure 10- Paper carrier imitation conveyance belt 33- Electric charge acquisition R 21- Seller body Figure 7 Figure 8 Figure 50- Insulation holding TPL meter 53. Between a pair of electrodes Figure 10 (1)

Claims (4)

[Claims] (1) A device for supporting and transporting paper materials, including a dielectric layer with a volume resistivity of 10^1^2 Ω/cm or more and a surface resistivity of 10^1^2 Ω/□ on the surface in contact with the paper material. A belt made of a conductor having a volume resistivity of 10^6 Ω·cm or less, and a charge injection means for injecting a charge into the paper material at the introduction part of the paper material to the belt surface. Material conveyance device. (2) In an ambient environment with a temperature of 33°C and a relative humidity of 80%, the volume resistivity is 10^1^2 Ω・cm or more, and the surface resistivity of the surface in contact with the transfer material is 10^1^2 Ω/□ or more. Claim No. 1 is characterized in that it is equipped with a transfer belt made of a dielectric material of
) The paper material conveying device described in item 2. (3) Paper material conveyance made of a dielectric material with a volume resistivity of 10^1^2 Ω/cm or more and a surface resistivity of 10^1^2 Ω/□ or more and a conductor with a volume resistivity of 10^6 Ω/cm or less belt. (4) The paper material conveying belt according to claim (3), characterized in that there is no seam step.