JPS62151877A - Transfer and conveyance device - Google Patents

Abstract

PURPOSE:To perform stable conveyance and secure transfer without any shift by passing a transfer material between an electrostatically charged conveyor belt and a conductive part which is provided in front of a transfer position in contact with it and connected to a DC power source. CONSTITUTION:The transfer material conveyor belt 111 consists of a dielectric layer 112 as a surface contacting the transfer material 117 and a conductor layer 13 as its reverse surface. An endless belt 111 supports electrostatically the transfer material 117 which is a sheet type or continuous in the moving direction and conveys it, and a support roller 114 and a driving roller 115 support and extend the belt and conveys it in a constant direction at a constant speed and an electrostatic charger 116 charges the dielectric part 112 of the conveyor belt 111. Further, this device is equipped with a means which grounds or applies an optional bias to the conductor part 113 of the belt 111 and a means which supplies the transfer material 117 through between the charged belt 111 and a conductor rubber roller 118 as the conductive member connected to the DC power source arranged in front of the transfer position in contact with the belt 113.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transfer/conveying device that electrostatically supports and conveys a transfer material and performs transfer onto the transfer material by physical or chemical means.

BACKGROUND OF THE INVENTION Several examples are already known of means for electrostatically conveying a transfer material by constructing a belt from an insulating member such as a dielectric material. For example, U.S. Patent No. 2.567.88
In the device described in the specification of No. 2, a conductive member and a dielectric member are bonded together to form a two-layer structure to constitute a conveyor belt, and the transfer material is supplied through between the conveyor belt and the charging member. For this reason, it can be seen as a method in which the paper is charged and then attracted to the belt, rather than being attracted to a pre-charged belt. FIG. 4 shows this embodiment. A dielectric belt 41 is supported and stretched by rollers 42 and 43. 44 is a metal belt and roller 4
6.47 is supported. 45 is a metal foil and dielectric bell 1-
It faces the metal belt 44 with 41 in between. The transfer material 48 is charged by the bias applied between the metal belt 44 and the metal foil 45. Reference numeral 49 short-circuits the metal foil 45 and the transfer material 4. 410 is a guide plate that guides the transfer material 48 to the bevel 41.

In the method described in US Pat. No. 3,357,325, a corona discharger is used for attracting and transferring a transfer material, and a dielectric single-layer belt is used. FIG. 5 shows a schematic diagram of the embodiment. 51 is a drum-shaped image support, 52 is a dielectric single-layer belt, and 53 and 54 are rollers for supporting, stretching, and rotating the dielectric belt 52. 55 is a roller for guiding the transfer material 56. 57 is a transfer material 56
A corona discharger 58 is used to transfer the charged powder image from the image support 51 to the transfer material 56 by electrostatic force.

Problems to be Solved by the Invention However, although the belt is a single layer of dielectric material in the belt described in U.S. Pat. When performing electrostatic transfer, it is necessary to provide a plurality of independent corona dischargers at the transfer position, each of which is a corona discharger dedicated to transfer. Also, U.S. Patent No. 2,57
In the device described in U.S. Pat. No. 6.882, it is possible to perform transfer and conveyance by combining the charging devices together, but due to its structure, the former U.S. Pat. No. 3.357
．． Similar to what is described in the specification of No. 325, when the conveyor belt and the transfer material are charged to the extent that sufficient conveyance force is obtained, static electricity is generated on the transfer material when the transfer material and the conveyor belt are separated. There is a very high possibility that the insulating charged particles transferred to the image will be disturbed and have an adverse effect on the transferred image. For this reason, in a conventional transfer device using a transfer/conveyance belt, it is essential to perform an operation to eliminate electric charges existing on the belt and the transfer material at a separation position between the transfer material and the conveyance belt. However, it is extremely difficult to completely remove all of the charges existing on the conveyor belt and the transfer material, and to do so, it is necessary to use a separate discharger connected to a special power source for charge removal. What you have to do is
This is shown in U.S. Pat. No. 3,244,083 and the like. Additionally, US Pat. No. 3.717.8 discloses that a special discharger and power source are used to charge the conveyor belt and transfer material.
Although this method is shown in the specification of No. 01, etc., it is difficult to say that it is a preferable method in view of economic reasons.

Furthermore, in the case of the transfer material described in US Pat. No. 2,576,882, if the transfer material is curled, there may be concerns about conveyance performance. In view of the above-mentioned problems, the present invention effectively utilizes the charged charge of the conveyor belt without using any special means in the charging device to achieve strong conveyance of the transfer material, and provides high quality transfer material without the need for complicated static elimination operations. An object of the present invention is to provide a transfer/conveyance device that obtains a transferred image.

Means for Solving the Problems In order to solve the above problems, the present invention includes a conveyor belt charged with a transfer material and a conductive member connected to a DC power source, which is provided in contact with the conveyor belt prior to the transfer position. It is designed to pass between.

By adopting the above structure, the present invention first transfers a portion of the electric charge accumulated on the dielectric surface to the transfer material when the transfer material conveying belt is charged, and connects it to ground or a suitable bias means at the time of charging. By attracting charges of opposite polarity to the dielectric part induced in the belt conductor,
Strong electrostatic adhesion between the transfer material and the conveyor belt is realized, and the transfer material is stably conveyed without shifting during transfer. Furthermore, in a transfer method that electrostatically transfers an image using charged particles, the charge transferred to the transfer material strongly attracts the charged particles, making it possible to prevent image distortion even when the conveyor belt and transfer material are separated. .

Further, since the transfer material is pressed against the belt and brought into close contact with the heald by electrostatic force, curling of the transfer material is not a major problem.

Embodiment Hereinafter, a transfer/conveyance device which is an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross section of a transfer/conveyance device in a first embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a rotatable drum-shaped image holding member (hereinafter simply referred to as a drum), in which a photosensitive dielectric layer such as selenium is coated on a drum-shaped conductor support such as aluminum. It was established. Usually this conductor support is grounded. First, this drum 11 is connected to the charger 12.
The drum 11 is uniformly charged, and at the next exposure portion 13, light that matches the original is imaged on the drum 11 through means (not shown), such as a lens. At this time, while the drum surface is uniformly charged, the charges on the parts exposed to light disappear by being neutralized with charges of opposite polarity induced in the conductor support on the back side of the photosensitive layer. A pattern of charges corresponding to the brightness and darkness of the original, that is, a latent image, is formed. This latent image is then processed into fine charged particles (hereinafter referred to as toner) in the developing section 14.
visualized by the electrostatic force between The toner image thus obtained on the drum 11 is transferred to a transfer position 15 on a transfer material 11 that is conveyed in synchronization with the toner image.
7 (hereinafter referred to as paper), and the remaining toner on the drum 11 is wiped off by means such as a blade in the cleaning section 16, and then the toner is transferred to the drum 11 by a uniform discharging light in the discharging section 17. The drum 11 is irradiated with static electricity and is prepared for the next process.

Here, part A is a transfer/conveyance device for paper, etc. according to the present invention. Bell) 111 is composed of two layers: a dielectric layer 112 on the outside and a conductor layer 113 on the inside. In this example, the thickness is 9
A sheet with a two-layer structure in which aluminum was vapor-deposited on one side of a 0 μm polyester film was cut out to a predetermined size, and the ends were welded using ultrasonic waves.

Of course, the outside can be made of dielectric material such as nylon or Teflon. The material of the inner layer does not matter as long as it is a conductor.

Furthermore, there is no problem in practical use even if the belt is formed as a single sheet by gluing sheets of dielectric material and conductor together.

The belt 111 is supported by rollers 114, 115 and stretched by means (not shown) of tension, such as a spring. The surface of the roller 115 is made of a conductor,
The conductor N113 inside the bell) 111 is connected to the roller 1 mentioned above.
It is grounded through 15. An appropriate bias may be applied depending on the situation.

The belt 111 is rotated by the roller 11 by a rotating means (not shown).
By driving the drum 5, the transfer section 15 is rotated in the same direction as the drum 11 and at the same circumferential speed. The surface of the dielectric portion 1120 on the outside of the conveyor belt is charged by the charging corotron 116 to a polarity opposite to that of the toner. This is because, for example, if the toner is negatively charged, the dielectric portion of the belt 111 is positively charged, and the electric field based on this positive charge electrostatically transfers the toner on the surface of the drum 11 to the belt 111 side. be.

Here, the paper 117 is sent between the roller 114 and a conductive rubber roller 118 connected to a DC power source 125 in synchronization with the drum 11 . In this embodiment, the conductive rubber roller 118 has a volume resistance of about 106 Ω from the member surface to the grounding position, and is strongly pressed against the roller 114 with the belt 111 sandwiched therebetween by means not shown. Therefore, even if the gi 117 is curled, the gi 117 can be pressed against the belt 111.

When the gi 117 passes between the conductive rubber roller 118 and the belt 111 and is brought into close contact with the belt 111, charge flows from the charged surface of the dielectric portion 112 of the belt 111 to the gi 117.At this time, how much is the paper charged? The capacitance and resistance of the air gap layer at the interface between the belt 111, the paper 117, and the conductive rubber roller, or the belt, the paper, and the conductive rubber roller, the output voltage of the DC power supply 125 connected to the conductive rubber roller 118, and Conductive rubber roller 11
Nip width when pressing 8 to belt 111, belt 111
determined by the circumferential speed of FIG. 2 shows an equivalent circuit that is thought to determine the distribution of charges flowing into the conductive rubber roller 118, and a schematic diagram showing the charge distribution after the shield 117 passes through the conductive rubber roller 118. Figure 2 (a
) is the equivalent circuit, and when the SW is ON, G117 is the bell! -1
11 and the conductive rubber roller 118. In FIG. 2(a), Q (bl is the amount of charge per unit area held by the belt 111 before reaching the conductive rubber roller 118, and Cb, Cp, and Ca.

Cr is belt 111 and Gio 117 per unit area, respectively.
, are the capacitances of the air gap layer and the conductive rubber roller 118, Rp, Ra, and Rr are the volume resistivity of the air gap layer and the conductive rubber roller 118 per unit area, respectively, and ■ is the DC power supply voltage. It is. belt 1
When a bias is applied to the conductive layer 113 of No. 11, the capacitance cb is grounded via the bias power source.

It is known that the electrical resistance and capacitance of paper vary greatly depending on the external environment, and especially in high humidity, the electrical resistance of paper decreases significantly and it becomes difficult to retain charge, making it difficult to expect stable transport. It disappears. The distribution of charges on the paper 117 and the belt dielectric surface at this time is shown in Figure 2~).Here, when the conductive rubber roller 118 is connected to the DC power supply 125, the charge distribution on the belt 111 and the belt 117 remains constant even under high humidity conditions. can leave behind a charge of FIG. 2(C) shows the charge distribution when the conductive rubber roller 118 is connected to the DC power source 125. On the other hand, if the humidity is low and the resistance value of the gi 117 increases, making it difficult to transfer the charge from the belt 111 to the gi 117, you can reverse the polarity of the DC power supply as shown in Figure 2 (C). good. The output of the DC power supply is the resistance value R of G117.
With respect to the change in p, Qp, which is the amount of charge on Gion 117, is 10
It may be adjusted so that it is equal to or higher than μC/nf.

At this time, the electrostatic attraction between the belt conductor portion 113 and the shield 117 is the product of the electric field strength E applied to the belt dielectric portion 113 and the amount of charge Qp of the shield 117. From this, the charge Qp transferred to the paper 117 by the conductive rubber roller 11B
The greater the number, the stronger the adsorption force will be generated. Therefore, the conductive rubber roller 118 is used to transfer charges from the belt 111 to the paper 117, and if it is a conductive member, the same effect can be expected regardless of the material and shape. Furthermore, if the resistance value of the conductive member becomes too large, the time constant that regulates the movement of charges becomes too large, which prevents injection of charges into the paper. A suitable range for the volume resistance is 10<11 >[Omega] or less between the part of the conductive member that contacts the transfer material and the ground position.

In this way, the paper 117 strongly attracted to the belt 111 reaches the transfer position 15 without worrying about falling off or slipping, and the paper 117 reaches the belt 111.
The toner image is electrostatically transferred from the opposing drum 11 onto the paper 117 by an electric field created by charges of opposite polarity to the toner distributed between the toner 1 and the toner 117.

After the transfer, due to the adsorption force between the paper 117 and the belt 111 and the rigidity of the gi 117 itself, the gi 117 is separated without the need for any special equipment, and the transfer is completed while the gi 117 remains in close contact with the belt 111.

Thereafter, the belt 111 and the paper 117 are separated by the curvature of the roller 115 and the rigidity of the paper 117 itself, and the paper is passed to the fixing guide 119, passes through the fixing device 120, and is conveyed to a paper output tray (not shown), where copying is completed. do.

U.S. Pat. No. 3,717,801 discloses that the charge on the charged dielectric belt and the charge on the toner on the belt 117 attract each other, and when the belt 117 and the belt 111 are separated, the toner scatters backward in the traveling direction, resulting in image disturbance. The issues that arise are addressed. As a countermeasure to this problem, U.S. Patent No. 3.717
．． In the one described in the specification of No. 801, a special operation is performed in the charging method. Furthermore, several methods have been proposed in which electricity is removed from the paper and the dielectric at a position where the paper and the belt are separated. However, by adopting the configuration of the present invention, the charge transferred to the paper itself strongly attracts the toner even after the belt and paper are separated, so a high-quality transferred image can be obtained without the need for a special charge eliminator. .

Further, in FIG. 1, reference numeral 121 denotes a belt cleaning device, which removes toner electrostatically by applying a bias of polarity opposite to that of the toner to a conductive fur brush, for example. It has been experimentally confirmed that when cleaning the toner adhering to the belt 111, the lower the amount of charge on the belt 111, the lower the bias voltage applied to the fur brush and the more efficient cleaning can be performed.

In the configuration shown in FIG. 1, the conductive rubber roller 118 is connected to the belt 111.
It has been found that this method has a significant effect on cleaning performance as well, since the electric charge is transferred to the belt 117 and the amount of electric charge on the belt 111 itself is reduced.

FIG. 3 is a diagram showing a second embodiment of the present invention, in which a metal fiber conductive brush 126 is used in place of the conductive rubber roller 118 in FIG. 1. In this case as well, effects similar to those of the configuration shown in FIG. 1 were obtained.

In the embodiments shown in FIGS. 1 and 3, the paper 117 is configured to be passed above the drum 11, but it is also possible to have a structure in which the paper 117 is passed to the side or below the drum 11. Furthermore, in Figures 1 and 3, belt 1
Although the conductor section 11 is kept in a grounded state, an appropriate bias may be applied to it.

Furthermore, in this embodiment, an electrophotographic copying apparatus is taken as an example, but the conveyance method according to the present invention can also be applied to a transfer/conveyance apparatus used in combination with other transfer methods, such as a transfer method that performs thermal transfer. It is possible.

Effects of the Invention As described above, the present invention is provided with a belt consisting of two layers: a dielectric material such as paper that is charged and a conductive material that is grounded or in a biased state, and is brought into contact with this belt prior to the transfer position. By feeding the transfer material between a conductive member connected to a DC power source, the charge is transferred from the belt dielectric part to the transfer material, and the transfer material is strongly attracted, ensuring stable conveyance without slippage and reliable delivery. By performing the transfer, it is possible to separate the belt and the transfer material without image disturbance and to efficiently clean the toner adhering to the belt without providing a special static eliminator.

[Brief explanation of drawings]

FIG. 3 is a cross-sectional view of a transfer/conveying device according to another embodiment, and FIG. 4 is a diagram of a known transfer material conveying device using electrostatic force. Schematic side view. FIG. 5 is a schematic side view of a known transfer/conveyance device using electrostatic force. 111... Conveyor belt, 112... Belt dielectric layer, 113... Belt conductor layer, 1
16... Charger, 117... Transfer material,
118... Conductive rubber roller, 125...
...DC power supply, 126... Conductive brush. Name of agent: Patent attorney Toshio Nakao Figure 2 (cl) //4° Roller/2.5・-X current power supply

Claims (5)

[Claims] (1) The transfer material conveying belt has a dielectric material on the surface that comes into contact with the transfer material.
An endless transfer material conveyance belt whose back surface is made of a conductive material and electrostatically supports and conveys the transfer material in the form of a sheet or continuous in the traveling direction; and an endless transfer material conveyance belt that supports and stretches the transfer material in a fixed direction. means for rotating the transfer material conveying belt at a constant speed; means for charging the dielectric portion of the transfer material conveying belt; means for grounding the conductive portion of the transfer material conveying belt or applying an arbitrary bias thereto; The method further comprises means for supplying the material through between the charged transfer material conveying belt and a conductive member connected to a DC power source, which is disposed prior to the transfer position so as to be in contact with the transfer material conveying belt. Characteristic transfer/conveyance device. (2) The conductive member has a distance of 10% between the part in contact with the transfer material and the ground.
The transfer/conveyance device according to claim 1, wherein the transfer/conveyance device has a volume resistance of ^1^1Ω or less. (3) The transfer/conveyance device according to claim (2), further comprising means for pressing a conductive member against the transfer material conveyance belt. (4) The transfer/conveyance device according to claim (3), wherein the conductive member has a roller shape. (5) The transfer/conveyance device according to claim (4), wherein the conductive member is a rubber material.