JP2001056577A - Photoconductive image forming member having erasure preventing additive in electric charge transfer layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming member having at least two electrically acting layers including an electric charge generating layer and an electric charge transfer layer, the latter being stabilized to erasure caused by the use of a corona charger. SOLUTION: Tetrakis methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)} methane is contained as an erasure preventing additive in the electric charge transfer layer of an electrophotographic image forming member. The electric charge transfer layer also contains aromatic amine hole transfer molecules and a continuous polymer binder phase. An electric charge generating layer is also included in the electrophotographic image forming member. The image forming member can be used in an appropriate electrophotographic image forming device. When tetrakis methylene(3,5-di-tert-butyl-4- hydroxyhydrocinnamate)} methane is contained in the electric charge transferring layer, erasure in an electrophotographic image formed using the image forming member is eliminated or substantially prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates generally to imaging members and the use of such imaging members in electrophotographic imaging devices and processes. More particularly, the present invention relates to a layered imaging member wherein the charge transport member comprises a hole transport molecule and a deletion preventing additive.

[0002]

BACKGROUND OF THE INVENTION In the electrophotographic art, an electrophotographic imaging member containing a photoconductive insulating layer is first imaged by uniformly electrostatically charging the imaging surface of the imaging member using, for example, a corotron. It is formed. The imaging member is then exposed to an activating electromagnetic radiation pattern, such as light, which selectively dissipates the charge in the illuminated area while leaving an electrostatic latent image in the unilluminated area of the photoconductive insulating layer. The electrostatic latent image is then developed by applying finely divided electroscopic marking particles to the surface of the photoconductive insulating layer,
A visible image can be formed.

[0003] Layered or composite imaging members, including flexible imaging members, are well known in the art. One such device includes a support layer, a photogenerating layer, and a charge transport layer, as described in US Pat. No. 4,265,990, which is hereby incorporated by reference in its entirety. Another layered imaging member is overcoated with a hole injection layer and then transported, for example, as described in US Pat. No. 4,251,612, which is also incorporated by reference herein in its entirety. It consists of a layer, a photogenerating layer, and finally a substrate overcoated with a top coating of an organic insulating resin.

[0004] The charge or hole transport layer is typically composed of an inorganic hole transport material dissolved in a polymeric matrix material, and the layer is capable of providing a spectrum for the intended application, such as visible light. Although substantially non-absorbing in the region, it is also active in that injection of photogenerated holes from the charged photogenerating layer can be achieved. Further, the charge transport layer allows for efficient transport of positive charges to the surface of the transport layer. The charge transport layer can include, for example, a hole transport molecule such as a diamine dispersed in a continuous polymeric binder.

As mentioned above, charging of the image forming member requires the use of a corona charging device such as a corotron, scorotron, dicorotron or pin charging device. However, the use of corona charging devices is problematic. During the charging operation, the corona charging device absorbs certain species, which are then considered to be detached from the corona charging device when the charging device is parked, i.e., at rest. This is particularly problematic when the corona charging device is placed on a portion of the imaging member. This is because of the acidic oxidative effluents (oxidized effluents) produced by and desorbed from the corona charger
Native effluents react with the hole transport molecules in the surface region of the transport layer, thereby oxidizing the hole transport molecules. This oxidation renders the transport layer surface conductive, resulting in a reduction in resolution due to a phenomenon known as parking deletion. When the imaging member containing such an erasure band is charged with a negative charge, the surface is rendered conductive, so that the next time printing is performed, the image charge pattern spreads laterally in that area, causing severe erasure. . In addition to parking erasure localized in the lower area of the resting corotron, exposure to corotron emissions during operation of the print engine results in oxidation of the charge transport molecules at the transport layer surface resulting in a resolution enhancement throughout the print area. A general decline will be caused. Surface oxidation results in an increase in surface conductivity and thus a reduction in resolution.

In an attempt to address this parking erasure and overall resolution degradation problems, the prior art discloses
Two methods were used. First, an acquadag coating on a corotron housing was used to reduce the production of acidic oxidative emissions by neutralization. Second, an air stream was used in the area between the corotron and the photoconductor to carry the effluent off during its production and minimize adsorption to the corotron. Such prior art methods were able to reduce the problem to a manageable level with low resolution copiers.

[0007] However, the demand for higher resolution (dots / inch) copies continues to increase. 60
Compared to black and white copying, where 0 dpi is sufficient, high quality color printing requires a resolution in the range of, for example, 1200 to 2400 dpi. The prior art methods discussed above include:
High resolution copying does not fully eliminate the oxidation of hole transport molecules in the associated erasure problem, and erasure therefore remains a significant problem.

What is needed is a more effective method to prevent erasure problems arising from the use of a corona charging device.

US Pat. No. 4,457,994 describes a stabilized organic layered device containing a diamine and triphenylmethane. US Patent No. 4,330,60
No. 8 describes a stabilized organic layered device comprising triphenylmethane and a substituted or unsubstituted benzotriazole. This device is stabilized against UV degradation. U.S. Pat. No. 4,232,103 describes a stabilized organic layered device comprising a diamine and a substituted or unsubstituted benzotriazole. This device is stabilized against UV degradation. U.S. Patent No. 5,401,615,
An organic layered device stabilized with an overcoat is described that includes a stabilizing additive selected from the group consisting of nitrones, isobenzofurans, hydroxyaromatics, and mixtures thereof. U.S. Pat. No. 5,391,447 describes a stabilized organic device having an overcoat comprising diamine and triphenylmethane. U.S. Pat. No. 4,397,931 describes a stabilized organic layered photoconductive device in which the charge transport layer comprises a compound of the general formula dispersed in a highly insulating and transparent organic resin material. The compound acts as a stabilizing substance in the charge transport layer. U.S. Pat. No. 4,563,408 describes an electrophotographic imaging member wherein the charge generating layer comprises a photoconductive material, a polymeric binder, and a hydroxyaromatic antioxidant. The hydroxy aromatic antioxidants are described as being phenol derivatives. See column 9, line 28 to column 11, line 48. U.S. Pat. No. 4,599,
No. 286 describes a photoconductive imaging member having a stabilizer in the charge transport layer. The chemical stabilizer is selected from the group consisting of certain nitrones, isobenzofurans, hydroxyaromatics, and mixtures thereof. U.S. Pat. No. 4,931,372 describes a light-receiving layer of a photoreceptor in which the surface portion of the outermost layer from the support comprises polycarbonate and a compound having a constrained phenolic structure. However, US Pat. No. 4,563,408
No. 4,599,286 and No. 4,931,
No. 372 lists the types of materials without clarifying the adverse consequences of using these compounds. Each of the U.S. patents described in this paragraph is hereby incorporated by reference in its entirety.

Although these references describe the use of a large number of stabilizing additives in various layers of an imaging member, any of these references is believed to be achieved in the present invention. N, N'-diphenyl-N, N'-bis (3-methylphenyl)-(1,1'-biphenyl)-
As an erasure preventing additive to a charge transport layer containing a hole transport molecule such as 4,4'-diamine (hereinafter referred to as TPD),
Tetrakisdimethylene (3,5-di-tert-butyl-4)
-Hydroxyhydrocinnamate) @ does not teach or suggest the surprising benefits associated with using methane.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to have at least two electroactive layers including a charge transport layer and a charge generation layer, wherein the charge transport layer is capable of protecting against erasure caused by use of a corona charging device. It is to provide an imaging member that is stabilized.

It is another object of the present invention to have at least two electroactive layers, including a charge transport layer and a charge generation layer, wherein the charge transport layer is stabilized against erasure caused by use of a corona charging device. It is an object of the present invention to provide an imaging member that does not have undesirable side effects such as crystallization of the transport layer as a result of changes introduced to be stable against such erasure.

Yet another object of the present invention is to have at least two electroactive layers, including a charge transport layer and a charge generation layer, wherein the charge transport layer is stabilized against erasure caused by use of a corona charging device. It is an object of the present invention to provide an imaging member that does not have undesirable side effects such as cycle up as a result of changes introduced to be stable against such erasure.

It is yet another object of the present invention to have at least two electroactive layers including a charge transport layer and a charge generation layer, wherein the charge transport layer is stabilized against erasure caused by use of a corona charging device. It is an object of the present invention to provide an imaging member that does not have undesirable side effects such as reduced sensitivity as a result of changes introduced to be stable against such erasure.

[0015]

SUMMARY OF THE INVENTION These and other objects of the present invention are achieved by incorporating certain anti-erasure additives into a charge transport layer containing aromatic amine molecules as charge transport molecules.

The electrophotographic imaging member of the present invention comprises a conductive layer, an aromatic amine hole transport molecule dispersed in a continuous polymeric binder phase, and tetrakisdimethylene (3,5-di-te).
a charge transport layer comprising an anti-erasure additive comprising rt-butyl-4-hydroxyhydrocinnamate) @methane and an adjacent charge generation layer. The imaging member can be used in any suitable electrophotographic imaging device.

The invention also relates to a process for eliminating or substantially preventing erasure of an electrophotographic image,
(1) A conductive layer and an erasure comprising an aromatic amine hole transport molecule and tetrakis {methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)} methane dispersed in a continuous polymer binder phase. An image forming member composed of a charge transport layer containing an anti-additive and (2) an adjacent charge generating layer is charged by a corona charging device to charge the image forming member, and the charged image forming member is used for electrophotography. Forming an image.

[0018]

DETAILED DESCRIPTION OF THE INVENTION In theory, an antioxidant could be used as an additive in the charge (or hole) transport layer of an imaging member to minimize oxidation in the layer. However, for such additives to be useful in electrophotographic printing equipment, several requirements must be met.

(1) The additive must be able to prevent, or at least substantially reduce, oxidation in the transport layer, especially of the hole transport molecule.

(2) The additive must not cause any trapping in the transport layer. When charge carrier traps are introduced into the charge transport layer, degradation of the light response characteristic occurs. The presence of the carrier trap results in the accumulation of residual charge, a phenomenon known as cycle-up. For example, cycle up in a 50,000 continuous cycle should be minimal (less than 20 volts).

(3) The additives are mixed in the charge transport layer, but some migration to the charge generation layer occurs. Photo-Induced Discharge characteristics,
Because the sensitivity of the imaging member as measured by the shape of the (PIDC) curve is a property of the charge generating layer, the change in PIDC shape caused by the presence of the additive should be minimal. Furthermore, even if the additive causes a change in the PIDC shape, it must be minimized so that the shape can be restored within specifications by the use of further additives such as trifluoroacetic acid.

The PIDC is measured as follows. Each photoreceptor device is mounted on a cylindrical aluminum drum substrate that is rotated about the scanner axis. Each photoreceptor is charged by a corotron mounted along the circumference of the drum. The surface potential is measured as a function of time by capacitively coupled voltage probes located at different locations around the axis. The probe is calibrated by applying a known potential to the drum substrate. The photoreceptor on the drum is exposed by a light source located near the drum downstream from the corotron. When the drum is rotated, the initial (pre-exposure) charge potential is measured by the voltage probe 1. Upon further rotation to the exposure station, the photoreceptor is exposed to monochromatic light radiation of known intensity. The photoreceptor is erased by a light source located upstream of charging. The measurements performed included charging the photoreceptor in a constant current or constant voltage mode. The photoreceptor is corona charged to negative polarity. As the drum is rotated, the initial charging potential is measured by the voltage probe 1. Upon further rotation to the exposure station, the photoreceptor is exposed to monochromatic light radiation of known intensity. The surface potential after exposure is measured by voltage probes 2 and 3. The photoreceptor is finally exposed to an erase lamp of appropriate intensity and the residual potential is measured by the voltage probe 4. The process is repeated with the exposure magnitude automatically changed during the next cycle. Photodischarge characteristics are obtained by plotting the potential of voltage probes 2 and 3 as a function of exposure.

(4) The additives must be compatible with all other components of the imaging member so as not to react with the other components. Thus, the additive must not adversely affect the performance of the hole transport molecule and not degrade the transport layer binder or the charge generation layer binder, for example, trigonal selenium, benzamidazole perylene, chlorogallium phthalocyanine Must be compatible with all of the pigments that will be used in the charge generating layer, such as hydroxygallium phthalocyanine.

Prior to the present invention, no antioxidants meeting all of the above criteria were known. However, extensive research has shown that the inventor of the present invention surprisingly
When added as an anti-erasing additive to the charge transport layer of an imaging member that also contains an aromatic diamine compound as a hole transport molecule, tetrakisdimethylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) ｝ I discovered that methane meets all of the above criteria. An anti-extinction additive is commercially available from Ciba-Geigy as Irganox 1010.

Irganox-259 (1,6-hexamethylenebis- (3,5-di-tert-butyl-4-hydroxyhydrocinnamate), Irganox-109
3 (0.0-di-n-octadecyl-3,5-di-tert
Some other Irganox such as -butyl-4-hydroxybenzylphosphonate), Irganox MD-1024 (1,2-hydrazinebis- (3,5-di-tert-butyl-4-hydroxycinnamoyl) are Causes severe cycle-up problem.Ilganox 101
0, as well as Irganox 259, 1093, and M
D-1024 is a hindered phenol. However, unlike these other bound phenols, Irganox 1010 surprisingly stabilizes the charge transport layer without severe cycling.

In a most preferred embodiment, the anti-erasure additive is included in a charge transport layer that includes TPD as a hole transport molecule.

[0027] In one embodiment, the layered imaging member comprises:
In the following order, an electrically conductive substrate, an optional blocking layer, an optional adhesive layer, a charge generation layer, a charge transport layer, and an optional overcoating layer can be included.
In another embodiment, the photoresponsive device comprises:
It includes an electrically conductive layer, an optional blocking layer, an optional adhesive layer, a charge transport layer, a charge generating layer, and an optional overcoating layer. The device may also have a grounding strip and an optional anti-curl backcoat (ACBC) layer.

In one preferred embodiment, the present invention provides
(1) a conductive substrate, (2) a charge blocking layer,
(3) an adhesive layer, (4) a charge generation layer, and (5) a charge transport layer composed of a certain aromatic diamine dispersed in an inert resin binder composition and containing the above-described erasure preventing additive. And (6) a protective overcoating layer.

These image forming members can be used in any type of electrophotographic image forming apparatus such as copiers, copiers and printing systems. These copiers, copiers, and printing systems can utilize various exposure means, such as a laser, for example, a gallium arsenide laser, or an image bar to generate the image to be developed.

The substrate may be opaque or substantially transparent,
Many suitable materials having the required mechanical properties can be included. The conductive layer or ground plane, which may include the entire support substrate and may be present as a coating or lower member (e.g., an inorganic material such as a metal or an organic material such as a polymer film), for example, aluminum, titanium, nickel, Chrome, brass, gold, stainless steel, carbon black,
Suitable materials including graphite and the like can be included. The thickness of the conductive layer can vary over a substantially wide range, depending on the desired use of the electrophotoconductive imaging member. Thus, the thickness of the conductive layer can typically range from about 50 angstroms to many centimeters. If a flexible photoresponsive imaging device is desired, the thickness may be about 100 Angstroms and about 5,000
It may be between 0 angstroms.

The lower member may be a conventional material including metals and plastics. Typical lower members include insulating, non-conductive materials of various resins known for this purpose, including polyester, polycarbonate, polyamide, polyurethane, and the like.

The coated or uncoated support substrate can be flexible or rigid, and can have a number of different shapes, such as, for example, plates, cylindrical drums, scrolls, membranes, endless flexible belts, and the like.

Preferably, the insulating substrate is in the form of an endless flexible belt and comprises a commercially available polyethylene terephthalate polyester known as Mylar from EI Dupont.

As described above, the image forming member of the present invention comprises:
It can include either electrically conductive or non-electrically conductive substrates. In particular, if a non-conductive substrate is used, it is preferred that an electrically conductive ground plane be used, which acts as a conductive layer. If a conductive substrate is used,
The substrate can act as a conductive layer, but a conductive ground plane may be provided if desired.

The ground plane is formed by solution coating, vapor deposition,
And by known coating techniques such as sputtering. The preferred method of applying the electrically conductive ground plane is vacuum evaporation. Other suitable methods can be used.

Under some circumstances, especially when the substrate is an organic polymeric material, polycarbonate materials commercially available as MAKROLON® from Farben-Fabriken Bayer AG or Goodyear Tire and Rubber Co., Ltd. It is desirable to coat the backside of the substrate with an anti-curl layer such as a copolyester resin such as Vitel PE-200 obtained from Co. Further, the anti-curl coating of embodiments of the present invention may include an adhesion promoter, preferably in an amount up to 10% by weight of the anti-curl layer. The anti-curl layer may also include a friction and / or wear reducing agent such as silica.

If desired, a suitable blocking layer may be inserted between the conductive layer and the charge generating layer. Preferred blocking layers include the reaction product between the hydrolyzed silane and the metal oxide layer of the conductive anode. The imaging member may comprise, for example, depositing a coating of a hydrolyzed silane aqueous solution at a pH of about 4 to about 10 on the metal oxide layer of the metal conductive anode layer and drying the reaction product layer to form a siloxane film. Prepared by applying an optional adhesive layer, generating layer, and charge transport layer to the siloxane film. Typical hydrolyzable silanes include 3-aminopropyltriethoxysilane, (N, N-dimethyl-3-amino) propyltriethoxysilane, N, N-dimethylaminophenyltriethoxysilane, N-phenylaminopropyl Includes trimethoxysilane, triethoxysilylpropylethylenediamine, trimethoxysilylpropylethylenediamine, trimethoxysilylpropyldiethylenetriamine, and mixtures thereof.

Generally, dilute solutions are preferred to achieve thin coatings. Satisfactory reaction product films can be achieved with solutions containing from about 0.1 weight percent to about 1.5 weight percent silane, based on the weight of the total solution.

Any suitable technique is available for applying the hydrolyzed silane solution to the metal oxide layer of the metal conductive layer. Typical application techniques include spraying, dip coating, roll coating, wire wound rod coating, and the like. Generally, satisfactory results can be achieved when the reaction product of the hydrolyzed silane and metal oxide layer forms a layer having a thickness between about 20 Angstroms and about 2,000 Angstroms.

To provide a reaction product layer having more uniform electrical properties, more complete conversion of the hydrolyzed silane to siloxane, and less unreacted silanol, the hydrolyzed silane on the metal oxide layer Drying or curing must be performed at a temperature above about room temperature. Generally, a reaction temperature of about 100 ° C. to about 150 ° C. is preferred to maximize stabilization of the electrochemical properties. This siloxane coating is disclosed in U.S. Pat. No. 4,464,450.
And the disclosure of which is incorporated herein in its entirety.

In some cases, an interlayer may be desired between the blocking layer and the adjacent charge generating or photogenerating material to improve adhesion or to act as an electrical barrier layer. If such layers are utilized, they are preferably from about 0.01 micrometer to about 5 micrometers.
It has a dry thickness between micrometers. A typical adhesive layer is polyester, Dupont 49,000 resin (E.
I. obtained from DuPont), polyvinyl butyral
And film-forming polymers such as polyvinylpyrrolidone, polyvinyl acetate, polyurethane, and polymethyl methacrylate.

[0042] Suitable charge generating or photogenerating materials can be used in one of the two or more electroactive layers of the multilayer photoconductor. The photogenerating layer may include a large number of photoconductive charge carrier generating materials if, for example, they are electronically compatible with the charge carrier transport layer, i.e., if the photoexcited charge carriers can be efficiently injected into the transport layer. Including.

The light absorption light generation layer (ie, charge generation layer)
Organic and / or inorganic photoconductive pigments can be included. Typical organic photoconductive pigments include vanadyl phthalocyanine and other phthalocyanine compounds such as hydroxygallium phthalocyanine, chlorogallium phthalocyanine, metal-free phthalocyanines, metal phthalocyanines such as copper phthalocyanine, for example, Monastral Red, Monastral Violet and Monas. Quinacridone obtained from DuPont under the trade name Tral Red Y, substituted 2,4-substituted disclosed in U.S. Pat. No. 3,442,781.
Diamino-triazine, squarin pigments such as hydroxysquarylium pigments, squarylium compounds, pyridinium compounds, azo dyes, diazo dyes, polynuclear aromatic quinones such as anthraquinone, and Indofast double scarlet and Indofast violet Lake B;
Examples include Indian Fast Brilliant Scarlet and Indian Fast Orange trade names obtained from Allied Chemical Company, thiopyrylium pigments, perylene pigments such as benzamidazole perylene, quinomeridone, or mixtures thereof.

Typical inorganic photosensitive pigments include amorphous selenium, trigonal selenium, mixtures of Group IA and IIA elements, As ₂ Se ₃ , selenium alloys, cadmium selenide, cadmium sulfoselenide, copper and chlorine doped. Cadmium sulfide, and mixtures thereof.

Preferred pigments include hydroxygallium phthalocyanine, chlorogallium phthalocyanine, trigonal selenium and benzamidazole perylene.

Suitable inert resin binder materials can be used in the charge generation layer. Typical organic resin binders include
Examples include polycarbonate, polyvinyl butyral, acrylate polymer, vinyl polymer, polyvinyl carbazole, polyester, polysiloxane, polyamide, polyurethane, epoxide, and the like. Numerous organic resin binders are disclosed, for example, in U.S. Pat. Nos. 3,121,006 and 4,439,507, the entire disclosures of which are incorporated herein by reference. The organic resin polymer may be a block, random, or alternating copolymer.

The photogenerating layer containing the photoconductive composition and / or pigment and the resinous binder material generally has a thickness of about 0.5 mm.
It has a thickness in the range of from 01 micrometers to about 10 micrometers, preferably from about 0.2 micrometers to about 3 micrometers. In general, the maximum thickness of this layer depends mainly on factors such as mechanical problems,
The minimum thickness of this layer depends on, for example, the particle size of the pigment and the optical density of the photogenerating pigment. Thicknesses outside these ranges can be selected.

However, the photogenerating composition or pigment is
Generally, it is present in the resin binder composition in various amounts from about 5 weight percent to about 80 weight percent of the layer, preferably from about 10 weight percent to about 50 weight percent of the layer. Thus, in this embodiment, the resin binder is present in an amount from about 95 weight percent to about 20 weight percent, preferably from about 90 weight percent to about 50 weight percent. The particular ratio selected will depend to some extent on the thickness of the generator layer.

The preferred charge transport layer used in one of the two electroactive layers of the multilayer or composite photoconductor prepared by the process of the present invention is from about 10 to 75 weight percent of at least one charge transport layer. An aromatic amine compound and a polymer film-forming resin in which the charge transport compound is uniformly dispersed. The charge transport layer generally has a thickness in the range of about 5 to about 100 micrometers, and preferably has a thickness of about 10 to about 40 micrometers, but thicknesses outside this range can also be used. .

The aromatic amine compound may be one or more compounds having the general formula

[0051]

Embedded image

Here, R ₁₂ and R ₁₃ are aromatic groups selected from the group consisting of a substituted or unsubstituted phenyl group, naphthyl group and polyphenyl group, and R ₁₄ is a substituted or unsubstituted aryl group, It is selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and cycloaliphatic compounds having 3 to 18 carbon atoms.

A charge transport aromatic represented by the above formula for a charge transport layer capable of assisting the injection of photogenerated holes in the charge generation layer and capable of transporting holes through the charge transport layer. Examples of amines include triphenylamine and N, N '
-Bis (alkyl-phenyl)-(1,1'-biphenyl) -4,4'-diamine (where alkyl is, for example, methyl, ethyl, propyl, n-butyl, etc.), N, N ' -Diphenyl-N, N'-bis (chlorophenyl)-(1,1'-biphenyl) -4,4'-diamine.

Most preferred is N, N'-diphenyl-N, N'-bis (3) dispersed in an inert resin binder.
-Methylphenyl)-(1,1'-biphenyl) -4,
4'-diamine (TPD). TPD has the following chemical formula:

[0055]

Embedded image

A suitable inert resin binder soluble in methylene chloride or other suitable solvent can be used in the process of the present invention. At least one to prevent excessive dark decay
0 ¹² ohm-cm preferably the inert highly insulating resin binder have a resistivity of, not necessarily the injection of holes from the light generating layer may not necessarily support material within these holes It is a material that cannot be transported. Typical inert resin binders soluble in methylene chloride or other suitable organic solvents include polycarbonate resins, polyesters, commercially available as Macrolon, Merlon, and Lexan,
Polystyrene, polyarylate, polyacrylate,
Polyether, polysulfone and the like are included. The weight average molecular weight is not critical or critical, for example, about 8.0
It may range from 00 to about 1,500,000, but is typically, for example, about 20,000 to 100,000.

The charge transport layer of the imaging member of this invention may also contain from about 0.1 weight percent to about 10 weight percent, preferably from about 0.5 weight percent to about 6 weight percent, of the anti-erasure additive described above. It is dispersed in it. Here again, this additive is tetrakis {methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)} methane and has the following chemical formula:

[0058]

Embedded image

This material is commercially available from Ciba-Geigy under the name Irganox 1010. This additive
A class of substances broadly identified as hindered phenols, containing four sterically hindered phenolic hydroxyl groups.

Moreover, the charge transport layer may further comprise one or more conventional additives. In particular, the charge transport layer can include an additive such as trifluoroacetic acid that can offset the change in sensitivity that can occur with the addition of the anti-erasing additive. Trifluoroacetic acid can be included in the charge transport layer in an amount of, for example, 0.1 to 10 weight percent.

Mixing the charge transport layer coating mixture,
Thereafter, suitable conventional techniques can be utilized for application to the imaging member. Typical application techniques include spray coating, dip coating, roll coating, wire wound rod coating, and the like.
Drying of the deposited coating can be effected by any suitable conventional technique, such as oven drying, infrared radiation drying, air drying, and the like.

The charge transport layer is used when the static charge placed on the imaging surface of the photoreceptor is fast enough to prevent an electrostatic latent image from forming and being retained thereon, and when there is no illumination. It must be insulating to the extent that it does not conduct or discharge. Generally, the ratio of the thickness of the charge transport layer to the charge generation layer is preferably maintained at about 2: 1 to 200: 1,
In some cases it is as high as 400: 1. A coating solvent such as methylene chloride can be used in forming the charge transport layer.

[0063] Optionally, an overcoating layer can also be utilized to improve abrasion resistance. These overcoating layers can include organic or inorganic polymers that are electrically insulating or slightly semiconductive. The overcoating layer typically has a thickness of about 0.
Having a thickness in the range of from about 0.05 micrometer to about 10 micrometers, preferably from about 0.2 micrometer to about 5 micrometers, to reduce ultraviolet light degradation of the material included in the transport layer and / or the photogenerating layer. Includes materials that can absorb ultraviolet light to minimize. This overcoating layer can also serve as a protective layer for the photoresponsive device.

The photoconductive imaging members described herein can be incorporated into various imaging systems, such as those conventionally known as xerographic imaging devices. Furthermore, the imaging members of the present invention can be selected for visible, near red and / or infrared imaging and printing systems. In this embodiment, the photoresponsive device is negatively or positively charged, and is about 700 to about 900, preferably 740 to 800 nanometers, such as continuously or simultaneously generated by a solid state laser such as an arsenide type laser. And then the resulting image is developed and transferred to a printing substrate such as a transparency or paper.
Further, the imaging members of the present invention can be selected for visible light imaging and printing systems. In this embodiment, the photoresponsive device is negatively or positively charged, exposed to light having a wavelength of about 400 to about 700 nanometers, then developed with a known toner, and then prints an image on a print substrate. Transfer and fix.

The present invention also includes a method of producing an image with the photoconductive imaging members disclosed herein. The method generally comprises first, for example, corotron, dicorotron,
Scorotron, pin charging device, bias charging roll (B
And CR) charging the image forming member with a corona charging device. Scorotrons are preferred. Next, an electrostatic image is generated on the photoconductive imaging member using an electrostatic imaging device as described above. The electrostatic image is then applied by known developing equipment to one or more developer compositions, such as compositions comprising resin particles, pigment particles, additives including charge control agents, carrier particles, and the like. Developed at further development stations. U.S. Pat. Nos. 4,558,108, 4,560,535, 3,590,000, 4,264,672,
Nos. 3,900,588 and 3,849,18
No. 2 is referenced. The disclosure of each of these patents is:
Which is fully incorporated herein by reference. The developed electrostatic image is then transferred at an image transfer station to a suitable printed substrate, such as paper or transparency, and fixed to the substrate. Image development includes cascade, touchdown, powder clouds,
This can be achieved by a number of methods such as magnetic brushes.

The transfer of the developed image to the printing substrate can be by any suitable method, including those in which a corotron or bias roll is selected. The fusing step can be performed by any suitable method, such as flash fusing, heat fusing, pressure fusing, steam fusing, and the like.

After the developed image has been transferred from the imaging member surface, the imaging member is preferably cleaned of residual developer remaining on the surface and charged before further or subsequent image development. Then, the residual electrostatic charge is also cleaned.

The use of an erasure preventing additive in the charge transport layer of the image forming layer of the present invention which contains an aromatic amine compound (particularly TPD) as the hole transport molecule allows for general erasure such as parking erasure from corotron Erasure problems in printed images, including both micro-erasures, such as the disappearance of single-byte images, and the like, are substantially eliminated. The additives do so by substantially reducing or eliminating the oxidation of hole transport molecules on the surface of the charge transport layer.

The additives accomplish erasure avoidance without adversely affecting other materials or properties of the imaging member.
In particular, additives only have a minimal effect on the sensitivity (shape of the photo-induced discharge characteristics) of the charge generation layer, and in general charge generation materials such as trigonal selenium, benzamidazole perylene and hydroxygallium phthalocyanine. , 5
It shows only a slight cycle up in a 000 consecutive cycles. In addition, the additive surprisingly reduces the depletion of imaging members utilizing benzamidazole perylene as a charge generating pigment, a random but common problem that plagues benzamidazole perylene receptors. Provide benefits. Depletion is
It is a phenomenon that reduces the charging potential from a maximum possible value called capacitive charging.

The following examples demonstrate the addition of anti-erasing additives in the charge transport layer as compared to imaging members containing commercial antioxidants containing some other hindered phenols or no stabilizing material. The surprising benefits achieved by using Irganox 1010 as an agent are further illustrated.

Example I Preparation of Photoreceptor (a) Preparation of Blocking and Adhesion Layers: The blocking and adhesion layers were formed on a substrate containing a titanium layer vacuum deposited on a polyethylene terephthalate film using conventional techniques. Prepared by forming a coating. The first coating formed on the titanium layer has a thickness of 0.1 mm.
A siloxane barrier layer formed from 005 micrometers (50 Angstroms) of hydrolyzed gamma aminopropyltriethoxysilane. The barrier layer coating composition is prepared by mixing 3-aminopropyltriethoxysilane (obtained from PCR Research Center Chemicals of Florida) and ethanol in a 1:50 volume ratio. The coating composition is applied by a multi-clearance film applicator,
Form a coating having a wet thickness of 0.5 mil. The coating is then dried at room temperature for 5 minutes, and then cured in a forced air oven at 110 degrees Celsius for 10 minutes. The second coating is an adhesive layer of polyester resin (49,000, available from EI Dupont) having a thickness of 0.005 micrometer (50 Å). The second coating composition is 0.5
The coating is applied using a mill bar and the resulting coating is cured for 10 minutes in a forced air oven. Three
The charge generation layers of two different pigments are coated as follows.

(B) Preparation of charge generation layer (1) Trigonal selenium (t-Se): The charge generation layer of trigonal selenium is prepared by adding about 0.05 micron in about 7 ml of tetrahydrofuran and about 7 ml of toluene. The adhesive layer is coated from a solution containing 0.8 grams of trigonal selenium having a particle size of between 0.2 and 0.2 micrometers and about 0.8 grams of poly (N-vinyl carbazole). The generator layer coating is applied with a 0.005 inch Bird applicator and the layer is dried at about 135 ° C. in a forced air oven to form a layer having a thickness of 1.6 micrometers.

(2) Benzamidazole perylene: 40
A charge generating layer of benzamidazole perylene (BzP) comprising volume percent BzP and 60 volume percent polycarbonate (PCZ) is coated on the adhesive layer. The photogenerating layer contained 0.45 grams of PCZ and 50 grams.
Prepared by placing ml of tetrahydrofuran in a 4 ounce tan bottle. To this solution, 2.4 grams of BzP and 300 grams of 1/8 inch diameter (3.2
Millimeters) of stainless steel shot is added.
This mixture is then placed on a ball mill for 72 to 96 hours. Subsequently, 2.25 grams of PCZ were dissolved in 46.1 grams of tetrahydrofuran and then the BzP
Added to the slurry. The slurry is then placed on a shaker for 10 minutes. The resulting slurry is then applied to the adhesive interface layer by using a ミ ル mil gap bird applicator to obtain a wet thickness of 0.5
Form a coating layer with a mill (12.7 micrometers). This light generating layer was placed in a forced air oven
Dry at 25 ° C. for 1 minute to form a dry photogenerating layer having a thickness of 1.0 micrometer.

(3) Hydroxygallium phthalocyanine (OHGaPc): 40 volume percent hydroxygallium phthalocyanine and 60 volume percent Mw1
Styrene with 1,000 (82 percent) / 4-
A photogenerating layer comprising a block copolymer of vinylpyridine (18 percent) is coated on the adhesive layer as follows. The photogenerating coating composition is prepared by dissolving 1.5 grams of a block copolymer of styrene / 4-vinylpyridine in 42 ml of toluene. To this solution is added 1.33 grams of hydroxygallium phthalocyanine and 300 grams of 1/8 inch diameter stainless steel shot. This mixture is then placed on a ball mill for 20 hours. The resulting slurry is then applied to the bonding interface using a bird applicator to form a layer having a wet thickness of 0.25 mil. This layer is dried in a forced air oven at 135 ° C. for 5 minutes to form a photogenerating layer having a dry thickness of 0.4 micrometers.

(C) Preparation of charge transport layer (1) No stabilizing additive: The transport layer is composed of 1 gram of N, N'-diphenyl-N, N 'dissolved in 11.5 grams of methylene chloride solvent. -Bis (3-methyl-phenyl)-
(1,1′-biphenyl) -4,4′-diamine (TP
D) and 1 gram of polycarbonate resin (poly (4,
4'-isopropylidene-diphenylene carbonate)
The charge generating layer (t-Se, BzP or OHG) is applied by using a bird coating applicator to apply a solution containing (obtained as Macrolon® from Farben-Fabriken Bayer AG).
aPc). N, N'-diphenyl-N, N'-bis (3-methyl-phenyl)-
(1,1'-biphenyl) -4,4'-diamine is an electrically active aromatic diamine charge transporting small molecule, whereas polycarbonate resin is an electrically inactive film-forming binder. 80 ° C in a forced air oven
For 30 minutes to form a dry 25 micrometer thick charge transport layer.

(2) With stabilizing additive: transport layer
1 gram of N, N'-diphenyl-N, N'-bis (3-methyl-phenyl)-(1,1'-biphenyl) -4,4'- dissolved in 1.5 grams of methylene chloride solvent
Diamine and 1 gram of polycarbonate resin (poly (4,4'-isopropylidene-diphenylene carbonate) (obtained from Farben-Fabrichen Bayer AG as Macrolon®) and 0.1 g
Formed on the charge generation layer (either t-Se, BzP or OHGaPc) by using a bird coating applicator to apply a solution containing grams of stabilizing additive. The coated device is dried in a forced air oven at 80 ° C. for 30 minutes to form a dry 25 micrometer thick charge transport layer.

Structure of Stabilizing Additive: In addition to the additive Irganox-1010 (the structure of which is described above), several other hindered phenols are tested. These include the following:

(1) Irganox-259: 1,6-
Hexamethylene bis- (3,5-di-tert-butyl-4
-Hydroxyhydrocinnamate

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(2) Irganox-1093 (0,0
-Di-n-octadecyl-3,5-di-tert-butyl-
4-hydroxybenzylphosphonate)

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(3) Irganox MD-1024
(1,2 hydrazine bis- (3,5-di-tert-butyl-4--4-hydroxyhydrocinnamoyl)

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(4) Phenol # 1: 2,2'-methylenebis (6-t-butyl-4-methylphenol)

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(5) Tinuvin 326 (chlorobenzotriazole)

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(6) Tinuvin 770

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Example II Using the procedure described in Example I, 21 photoreceptors were prepared. With no additives in the transport layer, three pigments t-
There are three control devices including Se, BzP and OHGaPc (Comparative Examples 1-3). The next three samples (Examples 1-3) each have one of the three pigments in the generator layer and are prepared with a transport layer containing 0.5 wt% Irganox 1010. The next three samples (Comparative Examples 4-6) each had one of the three pigments in the generator layer and 0.5 wt% Irganox 259
It is prepared having a transport layer containing The next three samples (Comparative Examples 7-9) each had one of the three pigments in the generator layer and 0.5 wt% Irganox 109.
Prepared with a transport layer containing The next three samples (Comparative Examples 10-12) each had one of the three pigments in the generator layer and contained 0.5 wt% phenol # 1.
It is prepared having a transport layer containing The next three samples (Comparative Examples 13-15) each had one of the three pigments in the generator layer and contained 0.5 wt% I Tinuvin 326.
It is prepared having a transport layer containing The next three samples (Comparative Examples 16-18) each have one of the three pigments in the generator layer and are prepared with a transport layer containing 0.5 wt% Tinuvin 770. Irganox MD-
Since the transport layer solution having 1024 gelled, the transport layer having Irganox MD-1024 could not be coated.

EXAMPLE III Testing of the Device of the Invention and Comparative Example: All 21 devices of Example II are first tested for xerographic sensitivity and cyclic stability. Each photoreceptor device is mounted on a cylindrical aluminum drum substrate that is rotated about the scanner axis. Each photoreceptor is charged by a corotron mounted along the circumference of the drum. The surface potential is measured as a function of time by capacitively coupled voltage probes located at different locations around the axis. The probe is calibrated by applying a known potential to the drum substrate. The photoreceptor on the drum is exposed by a light source located near the drum downstream from the corotron. When the drum is rotated, the initial (pre-exposure) charging potential is measured by the voltage probe 1. Upon further rotation to the exposure station, the photoreceptor is exposed to monochromatic light radiation of known intensity. The photoreceptor is erased by a light source located upstream of charging. The measurements performed include charging of the photoreceptor in a constant current voltage mode. The photoreceptor is corona charged to negative polarity. As the drum is rotated, the initial charging potential is measured by the voltage probe 1. Upon further rotation to the exposure station, the photoreceptor is exposed to monochromatic light radiation of known intensity. The surface potential after exposure is measured by voltage probes 2 and 3. The photoreceptor is finally exposed to an erase lamp of appropriate intensity and the residual potential is measured by the voltage probe 4. The process is repeated with the exposure magnitude automatically changed during the next cycle. Photodischarge characteristics are obtained by plotting the potential of voltage probes 2 and 3 as a function of exposure. Also, charge acceptance and dark decay are measured with a scanner. The apparatus is cycled continuously for 50,000 cycles for signs of residual cycle up. The results are shown in Tables 1 and 2.

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[Table 1]

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[Table 2]

In both Tables 1 and 2, VR is the initial residual potential after the erase step, and VR (50k) is
Continuous 50 in B zone (20C and 40% RH),
This is a cycle up after 000 cycles. The results indicate that, except for Irganox-1010 (all three pigments), tinuvin 326 (all three pigments), and phenol # 1 with OHGaPc, the remaining materials produce unacceptable initial residual potentials. Or cause an unacceptable cycle-up.

Example IV Test of Erasability Tolerance: The negative corotron is operated for several hours (at high voltage connected to the corotron wire) at a position opposite the grounded electrode. The high voltage is turned off and the corotron is placed (or parked) on the segment of the photoconductor device under test for 30 minutes. Thus, only a short intermediate segment of the photoconductor device is exposed to corotron effluent that is desorbed and impinges on the photoreceptor surface. The unexposed areas on both sides of the exposed area are used as controls. The photoconductor device is then tested with a scanner for the positive charging properties of the system using donor-type molecules. These systems are operated with a negative polarity corotron in the latent image formation step. The electrically conductive surface area (excess hole concentration) manifests itself as a loss of positive charge acceptance or increased dark decay in the exposed area (compared to the unexposed control area on either side of the short middle segment). Since the electrically conductive area is located on the photoreceptor device surface, negative charge acceptance scanning is unaffected by exposure to corotron emission (negative charges do not migrate through the charge transport layer consisting of donor molecules) ). However, excess carrier on the surface causes surface conductivity leading to reduced image resolution and, in severe cases, erasure. The measurement technique utilized in this example is known as a good surrogate for print testing, in connection with work done on erasure suppression. The photoreceptor device from Example II containing I-1010, Tinuvin 326 and Phenol # 1 and the control device without additives are tested for erasure resistance. Also tested is an apparatus having a transport layer containing a mixture of Tinuvin 326 (0.25 wt% based on total solids weight) and Tinuvin 770 (0.25 wt% based on total solids weight). The erasure test is not an absolute experiment and the results depend on the "efficacy" of the corotron (how long it has been running, the relative humidity, the life of the corotron, etc.). Thus, all devices are tested on the same corotron by placing the devices sequentially and placing the corotron on all devices simultaneously. The area not exposed to corona emissions was positively charged to 1000 volts in all five cases, while the corona exposed area of the apparatus with tinuvin 326 was charged to 500 volts (500 volt loss) and the apparatus with phenol # 1 Is charged to 700 volts (300 volt loss), the device with the mixture of Tinuvin 326 and Tinuvin 770 is charged to 350 volts (650 volt loss), and the control device without additives is charged to 300 volts (700 volts). The device with I-1010 charged near 1000 volts (substantially no voltage loss).

The data show a significant improvement in the oxidative stability of the surface of the device using the anti-extinction additive of the present invention (Irganox 1010). Tinuvin 326 or a mixture of Tinuvin 326 and Tinuvin 770 does not show a significant improvement in the oxidative stability of the transport layer surface. 2, as an additive
With 2'-methylene-bis (6-t-butyl-4-methylphenol) (phenol # 1) very little improvement is seen. Phenol # 1 is also t-Se
And BzP causes residual potential problems (Tables 1 and 2).

As shown by the data in Tables 1 and 2, very minimal changes are seen when Irganox 1010 is used as an anti-extinction additive. Irganox-259 shows unacceptable cycle-up for all three pigments, and Irganox-1093 shows high to very high residual potential and severe cycle-up for all three pigments. Phenol # 1 is trigonal selenium P
It shows a very bad adverse effect on IDC, and a bad cycle up with benzamidazole perylene. Tinuvin 770 is all three charge generating pigments, for example, 1
A tens of thousands of volts of cycle up at 0000 cycles is caused. Tinuvin 326 is known to be a stabilizer against UV-induced degradation, but shows no apparent increase in surface erasure resistance to corotron-induced degradation.

Further, the inventor has unexpectedly thought that the benzamidazole perylene is used as the charge generating pigment and that the image forming member containing trifluoroacetic acid in the charge transport layer contains the erasure preventing additive of the present invention. It has been found that such devices reduce the occurrence of depletion (caused by the presence of trifluoroacetic acid) on the order of about 50-70 volts. The occurrence of depletion reduces the charging capability of the device. This is a very surprising advantage of using anti-extinction additives.

 ──────────────────────────────────────────────────の Continuation of front page (72) Inventor John F. Janus United States of America 14580 New York Webster Little Birdfield Road 924 (72) Inventor Paul Jay. De Pheo United States 14555 Sodas Point, NY New York Street 7538 (72) Edward A. Inventor. Dam United States of America 14468 Hilton Post Avenue, New York 128 (72) Inventor Susan M. Van Doossen United States 14589 Williamson, Kylar Drive, New York 4107 (72) Inventor Dale S. Renfa United States 14580 New York Webster Adams Road 498

Claims (1)

[Claims] 1. A conductive layer, an optional charge blocking layer, an optional adhesive layer, a charge generating layer, and an aromatic amine hole transport molecule dispersed in a continuous polymeric binder phase, and tetrakisdimethylene (3,5- A charge transporting layer comprising: di-tert-butyl-4-hydroxyhydrocinnamate) @an erasure preventing additive comprising methane.