Abstract: A method of electrically charging a material to be charged by bringing a charging member impressed with a voltage into physical contact with the material to be charged, wherein the charging member is constituted by a flexible and electrically conducting endless sheet and a rotary insulating brush which supports the endless sheet at a position where the endless sheet and the material to be charged are in contact with each other and gives a pushing force to the endless sheet, and the endless sheet is driven actively or passively together with the insulating brush at a speed substantially in synchronism with the material to be charged while applying a charging voltage to the endless sheet. This method makes it possible to uniformly and stably charge the surface of the photosensitive material even when defects such as pinholes or the like exist in the surface of the photosensitive material, without causing the life of the photosensitive material to be shortened.

Abstract: A charging method for charging a photosensitive material of, for example, the photosensitive drum of an electrophotographic copying apparatus is accomplished by bringing an endless electrically conducting flexible sheet containing a brush roller into physical contact with the surface of the photosensitive material and applying a voltage to the electrically conducting flexible sheet. The electrically conducting flexible sheet is a laminate of a first resistance layer positioned on the side of the brush roller and a second resistance layer positioned on the outer surface of the first resistance layer. The second resistance layer has an electric resistance greater than that of the first resistance layer.

Abstract: In an electrophotographic apparatus using a charging apparatus for contact charging, the charging apparatus includes a flexible and hollow electrically conducting roller, and an electrically conducting brush roller which is provided in the hollow roller in concentric therewith and to rotate relative thereto, wherein a charging voltage is applied to the hollow roller via the brush roller, and the photosensitive material is electrically charged by rotating the hollow roller by bringing it into physical contact with the photosensitive material, and the hollow roller is brought at its both end portions into press-contact with the end portions on the surface of the photosensitive material and is rotated by being driven by the photosensitive material.

Abstract: An electrifying method which uses a electrifying a material wherein the contact-type electrifying member comprises a flexible and electrically conducting endless sheet and a brush which supports said endless sheet and imparts a pressing force thereto at a position where said endless sheet is in contact with the material to be electrified, said endless sheet which is impressed with an electrification voltage is driven or is moved at a speed which is substantially in synchronism with the material to be electrified, and the brush and the endless sheet are maintained at dissimilar speeds.

Abstract: A highly reliable sheet feed device for a copier, facsimile apparatus, printer or similar image forming apparatus and having a plurality of sheet storing portions which are arranged substantially horizontally and serially in an intended direction of sheet transport. The device surely feeds sheets from the storing portions one by one and eliminate sheet jams and defective sheet feed. Further, the device is simple and miniature and capable of accommodating a plurality of kinds of sheets therein.

Abstract: The method of feeding a developer according to the present invention is characterized by controlling the quantity of the developer fed to a developing zone, by the use of a member having on its surface an electret dielectric layer, which is used as an ear cutter. According to the present invention, the quantity of the developer being carried is controlled by the action of an electrostatic force exerted from the electret dielectric layer. Hence it becomes possible to effectively eliminate the density unevenness, charge unevenness of the developer and to obtain a stable image.

Abstract: A developing process for supplying a developer to a support having an electrostatic latent image thereon by using a developer-delivering member having an electret layer and carrying out the development so that the effective fog-controlling field intensity ratio (A) defined by the following formula: ##EQU1## wherein E.sub.L represents the surface potential of the latent image area in the support having the electrostatic latent image area, E.sub.B represents the surface potential of the non-image are and E.sub.S represents the surface potential of the electret layer, is in the range of from 0.01 to 0.6.According to this process, an image having a high density with no fog can be formed without applying a developing bias voltage.

Abstract: Disclosed is a heat-sensitive recording material capable of forming an image of a hue close to a pure black at a low density, which comprises a dispersion of a leuco dye, a heat-fusible organic acidic substance solid at normal temperature and a sensitizing agent in a binder, wherein the leuco dye comprises a fluoran type leuco dye for forming a black color and a benzofluoran type leuco dye for forming a red dye in an amount of 0.01 to 1% by weight based on said black color-forming leuco dye.

Abstract: Disclosed is a heat-sensitive recording element capable of forming an image of a hue close to a pure black at a low density, which comprises a dispersion of a leuco dye, a heat-fusible organic acidic substance solid at normal temperature and a sensitizing agent in a binder, wherein the leuco dye comprises a fluoran type leuco dye for forming a black color and a rhodamine lactam type leuco dye for forming a red dye in an amount of 1.5 to 30% by weight based on said black color-forming leuco dye.