This invention is generally directed to layered photoresponsive imaging devices, and more specifically to photoconductive devices having incorporated therein certain novel bisazo compounds. Therefore, in one embodiment of the present invention there are provided photoconductive layered imaging members comprised of certain bisazo compounds and arylamine hole transport layers. In one important embodiment of the present invention, there is provided a photoresponsive device comprised of various specific bisazo compounds, including 4,4'-bis(1"-azo-2"-hydroxy-3"-naphthanilide)-1,1'-dianthraquinonylamine; 4,4'-bis(1"-azo-2"-hydroxy-3"-naphtho-p-trifluoromethylanilide-1,1'-dianth raquinonylamine; and the derivatives thereof; and wherein the member further includes therein a charge, or hole transport layer. The aforementioned photoconductors possess a number of advantages indicated hereinafter inclusive of high photosensitivity, excellent photosensitivity to wavelengths of from about 400 to 750 nanometers, and high cyclic stability; and further, are very economical enabling these devices to be readily disposable. Accordingly, the photoresponsive imaging members of the present invention are useful in various electrophotographic and electrostatographic imaging processes wherein, for example, latent images are formed thereon followed by development and transfer to a suitable substrate. More specifically, the imaging members of the present invention with photosensitivity of from about 400 to about 750 nanometers enabled such members to be useful for electrophotographic imaging devices, and also these members can be incorporated into light emitting diode printers as well as multifunctional printer electrophotographic apparatuses.
Numerous different xerographic photoconductive members are known including, for example, a homogeneous layer of a single material such as vitreous selenium, or a composite layered device containing a dispersion of a photoconductive composition. An example of one type of composite xerographic photoconductive member is described, for example, in U.S. Pat. No. 3,121,006 wherein there is disclosed finely dispersed divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. These members contain, for example, coated on a paper backing, a binder layer containing particles of zinc oxide uniformly dispersed therein. The binder materials disclosed in this patent comprise a material such as polycarbonate resins, polyester resins, polyamide resins, and the like, which are incapable of transporting for any significant distance injected charge carriers generated by the photoconductive particles.
There are also known photoconductive members comprised of inorganic or organic materials wherein the charge carrier generating, and charge carrier transport functions are accomplished by discrete continuous layers. Additionally, layered photoconductive members are disclosed in the prior art which include an overcoating layer of an electrically insulating polymeric material.
Recently, there have been disclosed other layered photoresponsive devices including those comprised of separate generating layers, and transport layers as described in U.S. Pat. No. 4,265,990, and overcoated photoresponsive materials containing a hole injecting layer overcoated with a hole transport layer, followed by an overcoating of a photogenerating layer, and a top coating of an insulating organic resin, reference U.S. Pat. No. 4,251,612. Examples of photogenerating layers disclosed in these patents include trigonal selenium and phthalocyanines, while examples of transport layers include certain diamines as mentioned herein. The disclosures of each of these patents, namely U.S. Pat. Nos. 4,265,990 and 4,251,612, are totally incorporated herein by reference.
Many other patents are in existence describing photoresponsive devices including layered devices containing generating substances, such as U.S. Pat. No. 3,041,167 which discloses an overcoated imaging member containing a conductive substrate, a photoconductive layer, and an overcoating layer of an electrically insulating polymeric material. This member is utilized in an electrophotographic copying system by, for example, initially charging the member with an electrostatic charge of a first polarity, and imagewise exposing to form an electrostatic latent image which can be subsequently developed to form a visible image.
Furthermore, there are disclosed in U.S. Pat. Nos. 4,232,102 and 4,233,383 photoresponsive imaging members comprised of trigonal selenium doped with sodium carbonate, sodium selenite, and trigonal selenium doped with barium carbonate, and barium selenite or mixtures thereof. Moreover, there are disclosed in U.S. Pat. No. 3,824,099 certain photosensitive hydroxy squaraine compositions. According to the disclosure of this patent, the squaraine compositions are photosensitive in normal electrostatographic imaging systems.
Also known are photoconductive members containing therein various squaraine compositions. Thus, for example, there are illustrated in U.S. Pat. No. 4,508,803, the disclosure of which is totally incorporated herein by reference, photoconductive devices containing novel benzyl fluorinated squaraine compositions. Specifically, in one embodiment illustrated in the '803 patent there is described an improved photoresponsive device comprised of a supporting substrate, a hole blocking layer, an optional adhesive interface layer, an inorganic photogenerating layer, a photoconducting composition layer comprised of benzyl fluorinated squaraine compositions, and a hole transport layer. Other representative patents disclosing photoconductive devices with squaraine components therein, or processes for the preparation of squaraines include U.S. Pat. No. 4,507,408; 4,552,822; 4,559,286; 4,507,480; 4,524,220; 4,524,219; 4,524,218; 4,525,592; 4,559,286; 4,415,639; 4,471,041; and 4,486,520. The disclosures of each of the aforementioned patents are totally incorporated herein by reference.
Further, disclosed in the prior art are composite electrophotographic photosensitive materials with various bisazo compounds. For example, there are illustrated in Japanese Ricoh Patent Publication No. 6064354, published Apr. 12, 1985, composite photoconductors wherein one of the photoconductor layers contain a bisazo compound of the formulas as illustrated. Further, there are illustrated in several U.S. patents layered organic electrophotographic photoconductor elements with bisazo, trisazo, or related compounds. Examples of these U.S. pat. Nos. include 4,596,754; 4,555,567; 4,555,667; 4,440,845; 4,486,522; 4,486,800; 4,299,896; 4,551,404; 4,309,611; 4,418,133; 4,293,628; 4,427,753; 4,495,264; 4,359,513; 3,898,084; 4,400,455; 4,390,608; 4,327,168; 4,299,896; 4,314,015; 4,486,522; 4,486,519; and Konishiroku Japanese Patent Laid Open Publication No. 60111247.
Also of interest is U.S. Pat. No. 4,713,307, which illustrates photoconductive imaging members containing a supporting substrate, certain azo pigments of 2,7-bis(1'-azo-2'-hydroxy-3'-naphthanilide) naphthalene, and the derivatives thereof; and a charge transport layer.
Although photoconductive imaging members with bisazo compounds are known, there remains a need for novel bisazo photoconductor devices with extended red or near-IR photoresponses thereby enabling their selection in imaging apparatus with light emitting diodes. Additionally, there continues to be a need for layered photoresponsive imaging members have incorporated therein certain bisazo compounds, which members will enable the generation of acceptable high quality images, and wherein these members can be repeatedly used in a number of imaging cycles without deterioration thereof from the machine environment or surrounding conditions. Moreover, there is a need for improved layered photoresponsive imaging members wherein the bisazo compounds selected for one of the layers are substantially inert to the users of such members. Additionally, there is an important need for layered photoconductors with bisazo compounds, which photoconductors are of low cost, high sensitivity, and possess high cyclic stability. There also is a need for bisazo photoconductors that possess photosensitivity in the wavelength region of from about 650 to about 750 nanometers enabling these photoconductors to be selected for electrophotographic, particularly xerographic, imaging processes; light emitting diode printers; and multifunctional printer electrophotographic apparatuses.