JPH09106082A - Manufacture of multiactive photocondutive element and multiactive electrophotographic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve various problems in conventional manufacturing methods by containing no bead in an electric charge transporting layer. SOLUTION: This method comprises the steps of: (A) preparing a roll of flat polymer support having no knurled part and having beads protruding from one surface side; (B) applying vacuum coating of metal to the reverse surface to the surface including the beads of polymer support; (C) forming electric charge generation layer on the metal layer; (D) applying solvent coating of electric charge transporting layer containing no bead onto the charge generation layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the technical field of electrophotography.

[0002]

BACKGROUND OF THE INVENTION Multiactive electrophotographic elements are known. Generally, such elements include a conductive support in electrical contact with the charge generating layer and the charge transport layer.
For methods and materials for making these elements, see US Pat. Nos. 3,615,414 and 4,17.
It is described in many patent documents such as 5,960 and 4,082,551. These patent documents also describe how to use these elements.

One of the industrial methods for producing multi-active elements is to slit a roll-shaped support, whose width is not standardized and whose length is thousands of meters, while simultaneously cutting the knurls. Increase the thickness. The width of the roll is not standardized, so the width required in this way must be specially determined. In this step, knurls are placed in the center of the slit support and along the edges. The step of cutting the knurls includes applying rollers to the support. Since these rollers have a relief or embossed pattern, a relief pattern is formed on the part of the support to which the roller is applied. The knurls on the support assist in providing the slip required to transport the support and any layers above it on the rollers and planes. The knurling also allows the support to be wound into a roll, especially in a vacuum coating process.

The slit and knurled support is coated with a metal layer in a vacuum chamber and then slit again. The charge generation layer is solvent coated directly onto the metallized support. The charge transport layer containing the beads is then solvent coated onto the charge generating layer. These beads add texture to the top surface of the element. The texture is designed to improve handling at subsequent stages of the manufacturing process. A final slitting step is required to remove the portion of the element containing the knurled support. Another step in the manufacture of the multi-active element may include drilling the element and slitting it to a commercial width.

[0005]

There are several drawbacks to this manufacturing method. The support should be wide enough to accommodate the width of the desired multi-active element and the width of the knurled portion. The knurled part of the support is eventually disposed of, leading to waste and increased costs.
Also, the relatively thick elements obtained by knurling impose a limit on the length of the support that can be coated with the metal layer in a single batch in a vacuum coating chamber. Furthermore, the slitting step is necessary first because the width required for the starting material support is not standardized. Addition of beads to the charge transport layer presents solvent coating problems.
These beads tend to agglomerate and clog the applicator slots and filters. For this reason, the flow rate may be reduced or irregular, and the coating film may become non-uniform. Sometimes the beads are omitted by mistake,
Another problem arises, including disposal.

[0006]

According to the present invention, (A) a step of preparing a roll-like article of a flat polymer support in which beads are projected from one side and does not include knurls,
(B) vacuum coating a metal on the surface of the polymer support opposite to the surface containing the beads, (C) providing a charge generation layer on the metal layer, and (D) Solvent coating a bead-free charge transport layer on top of the charge generating layer.

By using a support in which the beads project from the surface opposite the metallization layer, there is no need for knurling, an initial slitting step and the inclusion of beads in the charge transport layer. Also, the exclusion of knurling can increase the length of the polymeric support that can be metal coated in a single vacuum coating step. The absence of beads in the charge transport layer solution reduces the above coating problems and copy artifacts. These supports can be used on other electrostatographic films, such as electrostatic films, and on copier receiver sheets, such as transparency or non-tearable "paper" (true white transparency). Can also be used.

In a multi-active electrophotographic element comprising a support carrying a metal layer, a charge generating layer and a charge transport layer in that order by the method described above, the support is provided on the side opposite to the surface on which the conductive layer is present. Provided is a multiactive electrophotographic element characterized in that beads are protruding from the surface and the charge transport layer is bead-free.

[0009] DETAILED DESCRIPTION An important requirement of the present invention the invention is that the beads at least one side using a flat polymeric supports protruding.
A wide variety of polymers are used as supports in the electrophotographic art. Such polymers are described, for example, in US Pat. Nos. 4,082,551 and 4,175,9.
No. 60 and other patents and literature referred to therein.

The beads are added to the entire cross section of the support or, alternatively, to a thin coextruded layer on one side of the support. The beads are 0.1 from the desired back side.
The protrusion is about 4.0 μm, preferably 0.1 to 1.0 μm. These protruding beads allow the support, and any layers present on its surface, to self as it rolls up and rolls or moves laterally over a large area flat surface. Sufficient separation is obtained so that it can slide against. This separation reduces the tendency of the support to become electrostatically charged when transported to or unwound from a charge inducing surface, such as a plush material used to prevent scratching of the film.

If it is assumed that the bead protrusion is 50% or less, the size of the beads should be limited to the range of 0.5 to 8.0 μm. Larger protrusions may make vacuum coating or solvent coating difficult. The shape of the beads can also affect the acceptable protrusions. Spherical beads or slightly flat beads have the least impact on the coating process. When extruded in the polymer and projecting only 50% of the diameter, such beads tend to be effectively fixed to the film base. Dusting and contamination by the removed beads is avoided. Further, when the bead protrusion height is 3 to 4 μm or less, the problems of contamination and transportation associated with relatively large beads are avoided. The number of beads present in the support is 50 parts or more beads per million parts of the support. This bead content is
An amount that guarantees a minimum number of protruding beads on at least one side.

In processes that use back irradiation or erase, haze should be kept below 4.0% to avoid undesired attenuation of the light source. Glass can be used because it is close to the refractive index of a suitable polymer support.
The use of glass allows relatively large amounts of bead material to be loaded into the copolymer resin without producing unacceptable haze. This is important if the beads are evenly distributed over the cross section of the film base. Polymer beads may be used because of their close refractive index. Although silica beads have very high toughness, they may develop unacceptable haze at very low loadings. However, as described above, when the beads are restricted to only a part of the cross section of the film, which is possible by using a thin coextrusion layer, large silica beads can be used in a relatively large amount.

Useful flat support polymers include biaxially oriented polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). Polyethylene terephthalate containing beads protruding from one side is commercially available from ICI under the trade name "Melinex" (TM). These supports have a standard width of 44
Available in rolls with inches (about 112 cm) and various lengths.

Then, the roll-shaped planar polymer support is coated with a metal layer in a vacuum chamber to form a conductive support. Silver, nickel, chrome, titanium, aluminum,
A metal layer obtained by vacuum-depositing the above is useful. Vacuum coated metal layers are known in the aforementioned patent documents. If desired, a conductive material such as nickel may be vacuum deposited on the transparent film support as a thin enough layer to produce an electrophotographic layer that can be illuminated through the transparent film support.

The flat support supply roll used in the present invention is loaded into the vacuum chamber of a vacuum coater.
Then, the air inside is exhausted. The metal, preferably nickel, is vaporized in a closed container inside the chamber. The support is unwound from the supply roll, transported across the opening in the top of the vaporization vessel, and wound onto a take-up roll.
As the support passes through the opening, metal adheres to the surface of the support opposite the surface containing the beads. This metal layer
It becomes the base layer of the charge transport layer and the charge generation layer that are subsequently coated.

Transporting a smooth, compliant support under vacuum in itself or on another smooth surface is not easy. Such surfaces are prone to block or adhere to each other. This makes it difficult to wind or steer the support when transporting or winding on a roll. The support used in the present invention does not have such difficulties. Moreover, the knurled support is relatively thin. This means that more and longer roll supports can be metallized in a single vacuum metallization step.

A charge generating layer is applied on the metal coated support obtained by the above vacuum coating process. The method of application depends, in part, on the charge generating material used in the layer. For example, vacuum deposition of a perylene pigment can be performed. In many cases, as with the charge transport layer, solvent coating is useful. A charge transport layer is solvent coated onto the charge generating layer. Most, if not most, compositions containing many conventional organic photoconductors are preferably coated using an organic solvent vehicle, so many organic solvent coating methods on an industrial scale are practiced in the art. ing.

Various coating solvents for preparing the multiactive element compositions useful in the present invention include substituted aromatic hydrocarbons (eg, toluene, xylene, mesitylene,
Etc.) and other aromatic hydrocarbons such as benzene;
Ketones such as acetone, 2-butanone, etc .; halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, ethylene chloride; cyclic ethers such as tetrahydrofuran, ethers including diethyl ether; mixtures of the above solvents. Can be mentioned.

Both charge transport layer and charge generating layer compositions are known. Again, the references cited herein above will provide sufficient information to those skilled in the art. Such "multiactive" photoconductive compositions contain a charge generation layer in electrical contact with the charge transport layer.
The charge generating layer of such a "multiactive" composition comprises a multiphase "aggregation" composition, as described above. Charge-transporting layers of such "multiactive" compositions are described in organic photosensitive charge-transporting materials such as those described in the above-referenced patents, eg, US Pat. No. 4,062,681, supra. P-type organic photoconductors such as arylamines, polyarylalkanes and pyrrole materials.

[0020]

EXAMPLES The coatings were applied to a metal coated support in a solvent coater. Such machines are commercially available. The machine used in the present invention coated three uniform layers in one pass.
The coating and drying characteristics were controlled to prevent coating artifacts. The charge generation layer (CGL) was applied at the first coating station. A charge transport layer (CTL) was applied on top of this CGL. At the second station, an additional carbon layer was applied to the edges of the CTL. This C
TL does not contain beads as in prior art methods. The bead-free charge transport layer extends along the edge of the charge generating layer and is in electrical contact with the metal layer. The carbon layer was coated along the edges of the charge transport layer which extended to the metal layer.

Although the present invention has been described with particular reference to the preferred embodiments thereof, it is understood that modifications and substitutions can be made within the spirit and scope of the invention.

Claims (2)

[Claims] 1. A step of (A) preparing a roll-shaped article of a flat polymer support in which beads are projected from one surface side and which does not include knurls, and (B) the beads of the polymer support. Vacuum coating a metal on the surface opposite to the containing surface; (C) providing a charge generating layer on the metal layer; and (D) transporting beads-free charge on the charge generating layer. Solvent coating the layer. 2. A multiactive electrophotographic element comprising a support carrying a metal layer, a charge generating layer and a charge transport layer in this order, wherein beads are applied from the surface of the support opposite to the surface on which the conductive layer is present. And a charge transport layer that is free of beads.