Abstract: An image forming method, comprising passing a toner image-bearing sheet through a nip defined between two rollers including a heater roller to fix the toner image on the sheet, wherein the toner image is formed from a toner comprising a binder resin, and a colorant, wherein the toner image before the passage through the nip has a toner volume V1 and a toner image area S1, wherein the toner image after the passage through the nip has a toner volume V2 and a toner image area S2, and wherein a volume change Vt and an area change St defined by the formulas shown below are 30% or less and 20% or less, respectively: Vt(%)=(V1?V2)/V1×100 St(%)=(S2?S1)/S1×100. Alternatively, the toner image before the passage through the nip has a surface roughness of 2.5 ?m or less.

Abstract: In an image forming apparatus configured to electrostatically transfer a toner image formed on an image carrier to a recording medium with image transferring means of the present invention, pressure is applied between the image carrier and the image transferring means. Toner is provided with relatively high hardness in accordance with the pressure beforehand. Image transfer is effected by reducing a potential difference between the image carrier and the recording medium while maintaining an electric field around the toner the same.

Abstract: In an image forming apparatus, a toner image is formed on a photosensitive element and a transfer roller, which carries a transfer medium, is pressed against a photosensitive element at a pressure of from 20.4 N/cm2 to 200 N/cm2.

Abstract: A toner including at least a binder resin; a colorant; a charge controlling agent; and a wax (B), in which the charge controlling agent comprises a compound selected from the group consisting of: an aromatic oxycarboxylic acids, derivatives of aromatic oxycarboxylic acid, salts of aromatic oxycarboxylic acids and salts of derivatives of aromatic oxycarboxylic acids; and a zirconium compound (A), and in which the zirconium compound (A) and the wax (B) have a weight ratio (A/B) satisfying the following relationship: 3.0≦(A/B)×100≦60.

Abstract: An electrophotographic image forming apparatus capable of reliably forming an image with density gradation, one which does not have a low-quality appearance. The estimated average halftone granularity of the toner image after developing but before electrostatic transfer was set at 0.25 or less. The average halftone granularity was found by measuring the granularity of a toner image at locations of different average brightness by means of newly proposed formula, and averaging the measured values for which the average brightness is 40 to 80. The estimated average halftone granularity was obtained by estimating the average halftone granularity of the toner image on a photoreceptor by means of a newly proposed method.

Abstract: In a copier which is an image-forming apparatus comprising a photoconductor 1, a developing apparatus 4, transfer apparatus 5 which transfers a toner image formed on the photoconductor 1 to a transfer material by heat and pressure using a transfer roller 52, and a fixing apparatus which fixes the toner image transferred to the transfer material, on the transfer material, a heater 56, temperature detection apparatus 57 and temperature control apparatus are provided which controls the temperature to within a range of from the glass transition temperature (Tg) to the softening temperature (Tm) of the toner, and lower than the fixing temperature of the fixing apparatus 7.

Abstract: An image forming method, comprising passing a toner image-bearing sheet through a nip defined between two rollers including a heater roller to fix the toner image on the sheet, wherein the toner image is formed from a toner comprising a binder resin, and a colorant, wherein the toner image before the passage through the nip has a toner volume V1 and a toner image area S1, wherein the toner image after the passage through the nip has a toner volume V2 and a toner image area S2, and wherein a volume change Vt and an area change St defined by the formulas shown below are 30% or less and 20% or less, respectively:

Abstract: A toner including at least a binder resin; a colorant; a charge controlling agent; and a wax (B), in which the charge controlling agent comprises a compound selected from the group consisting of: an aromatic oxycarboxylic acids, derivatives of aromatic oxycarboxylic acid, salts of aromatic oxycarboxylic acids and salts of derivatives of aromatic oxycarboxylic acids; and a zirconium compound (A), and in which the zirconium compound (A) and the wax (B) have a weight ratio (A/B) satisfying the following relationship:

Abstract: In an image forming apparatus, a voltage for a charger, a voltage for a light source for exposure or similar process condition for image formation is controlled such that a control parameter particular to image formation, e.g., the surface potential of an image carrier (light portion or dark portion) or the amount of toner deposited on the image carrier lies in a first predetermined tolerance width of a target value. Subsequently, the process condition is controlled such that the control parameter lies in a second predetermined tolerance width of the target value which is narrower than the first tolerance width. As a result, the control parameter is confined in the second tolerance width for achieving the final control accuracy.

Abstract: A toner recovery system is adapted to an image forming apparatus which carries out an image forming operation to form prints of a toner image on a photosensitive body using a toner.

Abstract: A toner density control method senses the concentration of a toner image for control formed on a photoconductive element by an optical sensor and, based on the output of the sensor, corrects a target target toner concentration for toner supplement control to be effected in response to an output of a toner concentration sensor mounted on a developing device. When the output Vs of the optical sensor is determined to be greater than a reference value Vs.sub.0 (short toner deposition), the reference value Vt.sub.0 is corrected to smaller one. When Vs determined to be smaller than Vs.sub.0 (excessive toner deposition), Vt.sub.0 is corrected to greater one. In each of such cases, a predetermined amount n.multidot..DELTA.VT is subtracted from or added to the output Vt of the toner concentration sensor of that instant.

Abstract: In an image forming method using an electrophotographic process, an amount of toner to be supplemented for maintaining a desired image density is estimated in response to input data which are a ratio of reflection densities produced by an optical sensor responsive to a pattern for control and an estimated toner consumption signal. Toner supplement control is executed on the basis of the result of estimation. The method sharply responds to a change in environment due to aging and a change in the kind of documents to thereby insure stable image density, compared to a conventional method relaying on an optical sensor or a toner sensor.

Abstract: An image developing bias voltage V.sub.B and controlling preset levels of latent image potentials V.sub.D, V.sub.L of reference black and white patterns are corrected based on a residual potential V.sub.R of the surface of a latent image carrier such that image developing potentials of the black and white patterns will be maintained at a constant level irrespective of how the latent image carrier is deteriorated.

Abstract: A method of controlling the density of images produced by an electrophotographic image forming apparatus to a constant value. A toner density sensor is provided with a first reference level variable in response to the output of an image density sensor, and a second reference level representative of a state associated with the optimum condition of a developer (e.g. immediately after replacement thereof). During usual control, the toner concentration of the developer is detected on the basis of the output of the toner density sensor, and the toner supply to the developer is controlled on the basis of the result of comparison of the detected toner concentration and the first reference level.

Abstract: A method applicable to an image forming apparatus which is implemented by an electrophotographic procedure for maintaining that the density of images to be produced by the apparatus is adequate at all times. When the density of a toner image of a reference image or a predetermined pattern sensed by the image density sensor lies in a predetermined adequate range, a sensing level associated with the toner density sensor responsive to the toner density of a developer is not changed. When the density of the toner image does not lie in the adequate range, it is determined that at least the sensing level of the toner density sensing being used at that time has to be changed. Then, whether or not the sensed density of the toner image of the reference image exists in a range in which the image density is controllable is determined.

Abstract: A toner density control device for an electrophotographic copier, facsimile apparatus, printer or similar image recorder of the type developing an electrostatic latent image formed on a photoconductive element, or image carrier, by using a developer in the form of a toner. The device includes a switch accessible for commanding a shift of an adjustable range of image density from a designed or standard range particular to the image recorder. The switch allows a person to select image density higher or lower than the standard adjustable range as desired.

Abstract: A cleaning device for an image forming apparatus which develops an electrostatic latent image provided on an image carrier with toner, transfers the resulting toner image to a transfer material, and cleans the image carrier to remove toner remaining thereon and, more particularly, a cleaning device of the type using a carrier retaining member which retains carrier thereon by a magnetic force. Carrier particles which form a magnet brush have volume resistivity of lower than 10.sup.10 .OMEGA..cm while toner particles have a dielectric constant of smaller than 3.7.

Abstract: A wire cleaning device has a cleaner movable for cleaning a charging wire in a corona discharger, and a motor for moving the cleaner. Whether or not the cleaner is locked somewhat in its stroke of movement is determined by signals from a position detector and a movement failure detector, or signals from an overcurrent detector and a timer. Alternatively, the cleaner which is locked in its moving stroke is forcibly moved by a larger amount of energy than normal, or is vibrated, on the basis of signals from a home position sensor and a failure detector.

Abstract: A toner concentration control method and system for controlling the toner concentration of a developer which includes toner and carrier for use in electrophotography. A controller, typically including a central processing unit or CPU, first determines a degree of deviation of the current toner concentration from a predetermined reference level and then replenishes the toner to the developer at an optimal replenishing condition which is varyingly set in accordance with the detected degree of deviation. In the preferred embodiment, the flow rate of toner to be supplied and time period of replenishing operation are varyingly set. Besides, the frequency of toner concentration detecting operation is also varyingly set so as to alleviate the load of the CPU.

Abstract: A recording image density control method for electrophotography comprising the steps of forming at least two latent electrostatic image patterns with different electric potentials on the surface of a photoconductor; developing the latent electrostatic images patterns to toner image patterns by use of toner contained in the developer; detecting data relevant to image density for each developed toner image pattern (such as the image density of each developed toner image pattern, for instance, by a toner image pattern, for instance, by a photosensor), with a different resolution for each image pattern; determining the ratio of the data for one image pattern to the data for the other image pattern by A/D conversion; and controlling at least one recording image density controlling parameter, such as the amount of the toner supplied to a development apparatus, in accordance with the ratio for controlling recording image density, whereby recording image density can be controlled.