JPS62215977A - Transfer and carrying device - Google Patents

Abstract

PURPOSE:To realize a stable carrying force in any environment by controlling an electrostatic capacity, etc., connected to a conductive material in accordance with the result of monitoring of a resistance of a transfer material, and controlling the carrying force of a prescribed carrying belt and the transfer material. CONSTITUTION:The resistance of a transfer paper carried by a carrying belt 111 which is formed by a conductive roller 118, a dielectric layer 112 of the surface electrified by an electrifier 116, and an electric conductor layer 113 connected to a ground is monitored by a surface potential sensor 122. In accordance with the result of this monitoring, a variable resistance 123, a variable capacity 124, etc., connected to the roller 118 are controlled, and in accordance with the variation of a time constant, an electrostatic current conducted from the layer 113 to a ground is controlled and the residual charge of the transfer paper 117 becomes a correct quantity, and the carrying force of the belt 111 and the transfer material 117 is controlled. According to them, the carrying force of the transfer material is stabilized in any environment, the transfer material 117 after transferring an image from a photosensitive body 11 is peeled off satisfactorily from the belt 111 without executing a destaticization, etc., and the image having the high quality is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transfer/conveyance 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 2.567.882
In the publication, 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 ion is charged and then attracted to the belt, rather than the ion being attracted to a pre-charged belt.

FIG. 5 shows this embodiment. 51 is a dielectric belt supported and stretched by rollers 52 and 53.

54 is a metal belt supported by rollers 56 and 57. A metal foil 55 faces the metal belt 54 with the dielectric belt 51 in between. The transfer material 58 is charged by the bias applied between the metal belt 54 and the metal foil 55. Reference numeral 59 short-circuits the metal foil 55 and the transfer material 58. A temporary guide 510 guides the transfer material 58 to the belt 51.

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. 6 shows a schematic diagram of the embodiment. 61
62 is a drum-shaped image support, 62 is a dielectric single-layer belt, and 63 is a drum-shaped image support.
．． 64 is a roller for supporting, stretching, and rotating the dielectric belt 62. 65 is a roller for guiding the transfer material 66. 67 is a corona discharger for adhering the transfer material 66 to the dielectric belt 62 by electrostatic force, and 68 is a corona discharger for transferring the charged powder image from the image support 61 to the transfer material 66.

Problems to be Solved by the Invention However, in US Pat. No. 3,357.325, although the belt is made of a single dielectric layer, the corona discharger is used to charge the transfer material and make it stick to the dielectric belt. When performing electrostatic transfer, it is necessary to provide a plurality of independent corona dischargers dedicated to transfer at the transfer position. Further, in U.S. Pat. No. 2.576.882, it is possible to perform transfer and conveyance by combining charging devices, but due to the structure, the former U.S. Pat.
, 357.325, when the conveyor belt and transfer material are charged to the extent that sufficient conveyance force is obtained,
When the transfer material and the conveyor belt are separated, the charged particles that have been electrostatically transferred onto the transfer material are disturbed, which is very likely to have an adverse effect on the transferred image. For this reason, conventional transcription
In a transfer device using a conveyor 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 conveyor 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. U.S. Patent 3.244
, No. 083, etc. Furthermore, as a method of charging the conveyor belt and the transfer material, the use of a special discharger and a power supply is shown in US Pat. Furthermore, in US Pat. No. 2,576.882, if the transfer material is curled, there is concern about conveyance performance. Furthermore, in the above configuration, no consideration was given to the fact that the conveyance force and transfer efficiency are reduced due to a reduction in the electrical resistance of the transfer material. In view of the above-mentioned problems, the present invention uses a special means for the charging device, and effectively uses the charged charge of the conveyor belt to achieve strong conveyance of the transfer material regardless of the decrease in electrical resistance of the transfer material. However, it is an object of the present invention to provide a transfer/conveyance device that can obtain a high-quality transferred image without going through a complicated static elimination operation.

Means for Solving the Problems In order to solve the above problems, the present invention uses a conveyor belt consisting of two layers: a charged dielectric part and a conductor connected to ground or an arbitrary bias power supply, and The transfer material is connected to a resistor and a capacitor, and the physical quantity corresponding to the electrical resistance of the transfer material provided in contact with the two-layer belt is monitored, and the values of the resistance and capacitance are controlled accordingly. The transfer material is configured to pass between the conductive members.

By adopting the above-mentioned 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 transfers the electric charge induced in the belt conductor which is grounded or biased. By attracting charges of opposite polarity to the dielectric part of the transfer belt, strong electrostatic adhesion between the transfer material and the conveyor belt is achieved, and the transfer material is conveyed stably without shifting during transfer. . At this time, by changing the resistance and capacitance values connected to the conductive member as the electrical resistance of the transfer material changes, the transfer material is always kept charged at a certain level or higher.
Stable conveying power can be achieved in any environment. Furthermore, in a transfer method in which an image using charged particles is electrostatically transferred, the charge transferred to the transfer material strongly attracts the charged particles, and it is possible to prevent image blur even when the conveyance belt and the transfer material are separated. Furthermore, since the transfer material is pressed against the belt and brought into close contact with the belt by electrostatic force, curling of the transfer material does not pose 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 a charger 1
2, the drum 11 is uniformly charged, and at the next exposure portion 13, light corresponding to 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 charge on the part exposed to light disappears by being neutralized with the opposite polarity charge induced in the conductor support on the back of the Angry Light WJ. , forming a pattern of charges corresponding to the brightness and darkness of the original, that is, a latent image. This latent image is visualized by the electrostatic force between it and fine charged particles (hereinafter referred to as toner) in the subsequent developing section 14. The toner image thus obtained on the drum 11 is electrostatically transferred at the transfer position 15 to a transfer material 117 (hereinafter referred to as paper) that is conveyed in synchronization with the toner image, and the remaining The toner on the drum II is removed from the cleaning section 16.
After being wiped away by means such as a blade, the static eliminator 17
Then, the drum 11 is irradiated with a uniform charge-eliminating light to eliminate the charge on the drum 11, and is prepared for the next process.

Here, part A is a transfer/conveyance device for paper, etc. according to the present invention. Belt lll has dielectric N112 on the outside and conductor J on the inside! Consists of two layers of J 113. In this example, a sheet having a two-layer structure in which aluminum was vapor-deposited on one side of a polyester film having a thickness of 90 μm was cut into a predetermined size, and the ends were welded using ultrasonic waves. Of course, as long as the outside is dielectric, such as nylon or Teflon, there is no problem.
The appropriate thickness is 10 μm to 200 μm. The material of the inner layer does not matter as long as it is a conductor, and its thickness is arbitrarily determined depending on the mechanical strength of the belt together with the dielectric layer. Furthermore, a belt can be formed as a single sheet by gluing sheets of dielectric and conductor together, or a dielectric layer can be formed by coating, gluing, dipping, etc. on a seamless endless conductor belt. In practice, there is no problem.

The belt 111 is supported by rollers 114 and 115, and is stretched by means (not shown) using tension such as a spring. The surface of the roller 115 is made of a conductor,
The conductor layer 113 inside the belt 111 is connected to the roller 11
It is grounded through 5. An appropriate bias may be added depending on the situation. The belt 111 is rotated by driving the roller 115 by a rotating means (not shown) so that the direction of movement in the transfer section 15 is the same as that of the drum 11 and the circumferential speed is the same. The surface of the dielectric portion 112 outside the conveyor belt is charged by a 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 111 is positively charged, and the toner on the surface of the drum 11 is electrostatically transferred to the belt 111 side by an electric field based on this positive charge. It is.

Here, the resistor 117 is a resistor 1 whose resistance and capacitance values are controlled by monitoring physical quantities corresponding to the electrical resistance of the roller 114 and the transfer material in synchronization with the drum 11.
23 and a conductive rubber roller 118 connected to a capacitor 124.

In this embodiment, the conductive rubber roller 118 has a volume resistance of 10
The belt 111 is approximately 6Ω, and is connected to the belt 111 by means not shown.
is strongly pressed by the scissor rollers 114.

The bell 117 passes between the conductive rubber roller 118 and the belt 111! When the belt 111 is brought into close contact with the belt 111, charges flow from the surface of the dielectric portion 112 of the belt 111 into the ring 117. At this time, how much the paper is charged is determined by the capacitance and resistance of the air gear knob layer at the interface between 111, 117, and the conductive rubber roller, or the heald, the paper, and the conductive rubber roller, and the connection to the conductive rubber roller. The values of resistance 123 and capacitance 124, the nip width when the conductive rubber roller 118 presses against the belt 111, and the belt 1
It is determined by the circumferential speed of 11.

Figure 2 shows the equivalent circuit, and when Sw is ON, G117 is the bell l.
-111 and the conductive rubber roller 118.

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. In FIG. 2, Q (b) is the amount of charge per unit area held by the belt 111 before reaching the conductive rubber roller 118, and Cb
+ Cp + Ca + Cr are belts per unit area, respectively. Cext is the capacitance of the variable capacitor 124, Rp, Ra, Rr
are paper 117 per unit area, air gear layer,
The volume resistance of the conductive rubber roller 118, Rext, is the resistance value of the variable resistor 123.

The distribution of charges on the paper 117 and the belt dielectric surface at this time is shown in the third diagram.
As shown in the figure. Here the resistor 1 connected to the conductive rubber roller
By changing the product of 23 and capacitance 124, that is, the time constant, it is possible to cancel the above-mentioned fluctuation in the amount of charge movement caused by the fluctuation in the electrical resistance of the capacitor. 1
The resistance value of 23 and the capacitance of 124 are such that, for example, if the electrical resistance of the paper decreases due to high humidity, the time constant of the charge leaking from the paper will become smaller, so the initial charge transfer from the belt will be small. It is sufficient to increase the time constants of 123 and 124 so that This has a resistance of 123 and a capacitance of 1
All you have to do is go in the direction of increasing the product of 24.

FIG. 4 shows the distribution of charges on the sleeve 117 and the belt 111 under high humidity when the product of the values of the resistance 123 and the capacitance 124, that is, the time constant, is increased.

Although the values of the resistor 123 and the capacitance 124 must take into account various variables in the equivalent circuit shown in FIG. 2, it is sufficient to set the amount of charge on the paper 117 to approximately 10 μC/rd or more. By changing the time constants of the resistance 123 and capacitance 124 as the electrical resistance of the paper 117 decreases, a constant and stable conveying force is achieved regardless of the decrease in the electrical resistance of the paper 117. can do. At this time, the electrical resistance of the paper 117 is monitored by the i-plane potential sensor 122 shown in FIG. The value of fl 124 may be changed, or the values of resistance 123 and capacitance 124 may be controlled using a sensor that monitors a physical layer different from that shown in FIG. Alternatively, only one of the resistance value 123 and the capacitance value 124 may be changed.

Furthermore, when the electrical resistance of the gi 117 increases due to low humidity, the charge is simply divided by the capacitance of the belt dielectric 112, the gi 117, and the conductive rubber roller 118.
If the capacitance of the cap 117 is small, the charge remaining on the belt dielectric layer will be larger than that of paper, resulting in image distortion when the cap 117 separates from the conveyor belt 111.

In this case, the values of the resistance 123 and the capacitance 12.4 may be changed in a direction that reduces the time constant, contrary to the case of high humidity. In this case as well, either the resistor 123 or the capacitance i 124 may be fixed.

At this time, the electrostatic attraction between the belt conductor part 113 and the shield 117 is the product of the electric field strength E applied to the belt dielectric part 113 and the amount of charge Qp of the shield 117. From this, the charge Qp transferred to the wire 117 by the conductive rubber roller 118
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 belt 117, and if it is a conductive member, the same effect can be expected regardless of the material and shape.

In this way, the Gion 117 that was strongly attracted to the belt 111 reaches a transfer value of 15 without worrying about falling off or slipping, and is transferred by the electric field created by the toner distributed on the belt 111 and the paper 117 and the charges of opposite polarity. The toner image 117 is electrostatically transferred from the drum 11 facing the drum 11 .

After transfer, the adsorption power of paper 117 and bell) 111 and Gion 117
Due to its own rigidity, the shield 117 is separated without the need for any special device, and the transfer is completed while the shield 117 remains in close contact with the belt 111.

After that, 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, passed through the fixing device 120, and conveyed to a paper output tray (not shown) to be copied. Complete.

U.S. Pat. No. 3,717,801 discloses an image in which the charge on the charged dielectric heald and the charge on the toner on the paper 117 attract each other, and when the belt 117 and the belt 111 are separated, the toner flies backward in the direction of travel. Issues that cause disturbances are addressed. As a countermeasure to this, U.S. Patent No. 3,717
, No. 801, a special operation is performed on 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 charges transferred to the paper continue to strongly attract the toner even after the belt and paper are separated, so a high-quality transferred image can be produced without the need for a special charge eliminating section. can get.

In FIG. 1, reference numeral 121 is a belt cleaning device, which electrostatically removes toner by applying a bias of polarity opposite to that of the toner to a l-M fur brush, for example. .When cleaning the toner attached to the bell l-111, use the bell l-111.
It has been experimentally confirmed that the lower the charge amount of 111, the more efficient cleaning can be performed with a lower bias voltage applied to the fabric brush. With the configuration shown in FIG.
It was found that reducing the amount of charge on No. 11 itself had a significant effect on cleaning performance.

In the embodiment shown in FIG. 1, the shield 117 is configured to pass above the drum 11, but it is also possible to have a structure in which it passes through the side or below the drum 11.

Further, 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 leisurely 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. , transfer between a conductive member connected to a variable resistor and capacitance that monitors the physical quantity equivalent to the electrical resistance of the transfer material and changes the time constant consisting of resistance and capacitance depending on the result. It has a configuration in which the transfer material is fed from the belt dielectric section to the paper, and is charged with a charge above a certain level in any environment, strongly adsorbing the transfer material, and ensuring stable conveyance without deviation and reliable transfer. , it is possible to separate the belt from the transfer material without disturbing the image and to efficiently clean the toner adhering to the belt without providing any special static eliminator.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a transfer/conveyance device according to an embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram for explaining the transfer of electric charge from a charged transfer/conveyance belt to a transfer material according to this embodiment. FIG. 3 is a schematic diagram showing a state in which when the roller 118 is directly grounded, the resistance of the transfer material is low and most of the charge is lost from the transfer/conveyance belt and the transfer material. FIG.・A schematic diagram showing the effects of resistance and capacitance on the charge distribution when a transfer material with the same resistance as that shown in Figure 3 is transported by a transport device. FIG. 6 is a schematic diagram of a known transfer material conveying device that utilizes electrostatic force. 11...Drum, 12...Charger, 1
3...Exposure section, 14...Development section, 15
...Transfer section, 16...Cleaning section, 17...Static elimination section, 111...Transfer section
Conveyor belt, 112... Belt dielectric layer, 11
3...Belt electric layer, 114...Followed roller, 115...Drive port-ra, 116
...Charger, 117...Transfer material, 11
8... Conductive roller, 119... Fixing guide, 120... Fixing device, 121...
...Conductive fur brush for cleaning, 122...
...Surface potential sensor, 123...Variable resistor,
124... Variable capacitor, 125... Control device. Name of agent Patent attorney Toshio Nakao (1 person) Figure 1 Figure 2 33 Figure 5 t Figure 6

Claims (2)

[Claims] (1) In a device that electrostatically supports and conveys a sheet-like or continuous transfer material in the traveling direction using an endless transfer material conveying belt and physically or chemically transfers an image to the transfer material, The transfer material conveyance belt has a surface in contact with the transfer material made of a dielectric material and a back surface made of a conductive material, and includes means for supporting and extending the transfer material conveyance belt and rotating in a fixed direction at a constant speed; means for electrically charging a dielectric portion of the transfer material conveying belt; means for grounding or applying a desired bias to a conductive portion of the transfer material conveying belt; A means for supplying a transfer material between a conductive member placed prior to the transfer position, a means for monitoring a physical quantity corresponding to a resistance value of the transfer material, and a means connected to the conductive member in accordance with this. A transfer/conveying device characterized by comprising means for controlling the resistance value or capacitance of a resistor. (2) When transferring charged particles electrostatically, the output of the bias is 10 μC/
The transfer/conveyance device according to claim (1), wherein the transfer/conveyance device is set to be charged to m^2 or more.