Abstract: To correct the distance between respective drums and supply image data, an image processing system using a 4-drum type color image forming apparatus requires a large-capacity image memory for temporarily storing transferred image data, and is inevitably expensive. In this invention, image data of four colors isochronously transferred via a high-speed serial interface such as an IEEE 1394 interface are respectively supplied to image processing units and image forming units via delay memories. Therefore, the time difference required for the print sheet to reach each drum can be corrected in each image forming unit to appropriately form an image at a high speed and low cost.

Abstract: An image forming apparatus includes a printer body having a developing portion and a fixing portion therein, a plurality of sheet feeding rollers provided along a sheet discharge path successively and driven to discharge a sheet passing through the fixing portion to an upper portion of the printer body, and a rear cover provided on a side of the printer body to open and close, and having guide ribs to guide the sheet passed through the fixing portion. The image forming apparatus also includes an idle roller provided movably on the rear cover, to contact and rotate with one of the sheet feeding rollers to feed the sheet, and a supplementary guide member provided rotatably on the rear cover and positioned below the idle roller. The supplementary guide member changes a position thereof when the rear cover is open so that the sheet being discharged directly to the guide ribs is prevented from running into the idle roller.

Abstract: A developing apparatus is equipped with a developing container accommodating a developer including a toner and a carrier to develop at a developing position an electrostatic image formed on an image bearing member, a rotor for rotating the developing container in a path including the developing position, and a developer replenishing container for replenishing the developing container situated at the developing position by said rotor with the developer. An opening is provided on a side surface of the developing container, which allows surplus developer to spill out of said developing container situated at said developing position by said rotor. The apparatus is further equipped with a recovering container and a member for opening/closing the opening mentioned above. The recovering container recovers the surplus developer discharged from said opening utilizing a rotational motion of said rotor.

Abstract: Disclosed is a scanning optical apparatus which can reduce color misregistration in a sub scanning direction to thereby obtain a good color image output, and a color image forming apparatus using the same. In the scanning optical apparatus, a beam emitted from light source means 1 is deflected by deflecting means 5, and the beam deflected by the deflecting means is imaged in a spot shape on a surface 7 to be scanned by scanning optical device, and light-scans on the surface to be scanned, and a scanning line scanning on the surface to be scanned has two or more extremums within the effective range of a scanning area.

Abstract: One color is determined as a reference, and adjustment is carried out such that other color is matched with a detection signal generated from a synchronous detector of this color. Each control circuit of other color generates a mark pulse signal by determining an optional position based on a DP generated from each synchronous detector. A reference color control circuit receives a mark signal, and measures time relative to the reference. A CPU checks whether a result of this measurement coincides with a target value. The CPU changes the setting according to the difference, and repeats the measurement until when there is no difference, thereby obtains an adjustment value.

Abstract: The fixing device having therein the heating member for heating a toner image, the pressure applying member arranged to face the heating member for performing a pressure contact to the heating member, an urging means which urges the pressure applying means, and a changeover means which changes the condition of the pressure applying member from the pressure contact condition to the heating member to the pressure contact released condition by controlling the urging means, wherein urging power by the urging means under the pressure contact released condition is lower than that under the pressure contact condition.

Abstract: An optical scanning device includes a plurality of light sources, a drive circuit connected to the light sources to drive the light sources independently with from each other in a modulating manner, a deflector having a plurality of deflecting surfaces to deflect rays emitted from the light sources and scan imaging optical systems directing the deflected rays onto different scan surfaces respectively. The optical scanning device further includes synchronization detection means for receiving the rays before start writing onto the scan surface and outputting synchronization detection signals, delay time adjusting means for adjusting delay time, the delay time being a time period after outputting the synchronization detecting signal until starting the writing operation, and frequency adjustment means for adjusting driving frequencies of the light sources.

Abstract: An image forming apparatus in which the flux density of a main magnetic pole for development has an attenuation ratio of 40% or above in the normal direction is disclosed. Assume that a period of time of T1 is necessary for a photoconductive element to move by a single dot at a nip for development. Also, assume that, in a single period of an alternating electric field applied to a developing sleeve as a bias, the duration of an electric field causing toner to move toward the photoconductive element is T2. Further, assume that the duration of an electric field causing the toner to move toward the sleeve is T3. Then, a relation of T1>T2>0 or a relation of T1>T3>0 holds.

Abstract: An image forming apparatus includes an image bearing member; a developing device for developing a latent image formed on the image bearing member, the image bearing member and the developing means being detachably mountable to the apparatus as a process unit; a developer supply unit for supplying a developer to the developing means, the developer supply unit being detachably mountable to the apparatus; and a first memory mounted on the process unit. The first memory stores information relating to the developer supply unit.

Abstract: In an image forming apparatus of the present invention, the voltage of a chargeable layer 2b of an image carrier 2 at the portion to be in contact with writing electrodes 3b is adjusted by a surface potential adjusting member 8 which is disposed to be in contact with the chargeable layer 2b between the writing electrodes 3b and a transfer roller 6a. That is, even if the reverse charge injection occurs because the transfer voltage is applied to the transfer roller 6a and the transfer roller 6a is in contact with the chargeable layer 2b of the image carrier 2 at an interval between a printed paper 5 and the next paper 5, the potential of the chargeable layer 2b at the portion to be in contact with the writing electrodes 3b is adjusted not to exceed the withstand voltage of IC drivers 7 of the writing electrodes 3b by the surface potential adjusting member 8.

Abstract: An image forming apparatus has an image bearing member; and a charging member forming a nip with the image bearing member to charge the image bearing member. Conductive particles are provided in the nip and a time factor &agr; represented by a following equation satisfies a condition &agr;>15: &agr;=2&pgr;·k·Nc·(W/Vc)/(&rgr;·Cd·Z) Z=−0.5·1n(&pgr;·k·Nc)−1n({square root over (&bgr;)}·D/2) (&bgr;=1.

Abstract: A method of aligning and registering duplex images in the process direction using an imaging device, such as a printer including the steps of applying a first image to a first side of a media, modifying one or more imaging parameters of the imaging device after the first image is applied, and applying a second image to a second side of the media using the modified imaging parameters.

Abstract: An electrostatographic machine having a transfer station including a toner image carrier and a transfer member for electrostatic transfer of toner from the toner image carrier to a toner-image area on a receiver sheet in a nip formed between the toner image carrier and the transfer member. Receiver sheet has a leading edge included in a leading edge margin area and a trailing edge included in a trailing edge margin area. A programmable power supply supplies and controls transfer station current. Before the leading edge enters the nip and after the trailing edge leaves the nip, but not while the toner-image area is in the nip, transfer station current is successively switchably altered by the programmable power supply between at least two predetermined magnitudes. The transfer station current is preferably zero, of a low magnitude, in at least a portion of the leading edge margin area so as to effectively suppress wrap.

Abstract: An image forming apparatus having a photoreceptor, a developing section, a transferring section, and a cleaning section, wherein the toner is manufactured by a polymerization method, particle diameter is 3-8 &mgr;m, and a shape factor of the toner is 0.940-0.985. The cleaning section has a rubber blade, and a brush roller implanted with brush fibers, wherein a value of effective rubbing force F, defined by the following expression, of brush fibers is in a range of 2.5-10.5, F=nxyEt3/L3, wherein, “n” represents implanted density of the brush fibers (fibers/mm2), “x” represents a linear speed difference between the brush fibers and the photoreceptor (mm/s), “y” represents an encroaching amount (mm) of the brush fibers upon the photoreceptor, “E” represents Young's modulus (kgf/mm2), “t” represents a diameter (mm), and “L” represents a free length (mm) of the brush fibers.

Abstract: There is described a method of controlling the rotational peripheral speed of the rotating photoreceptor drum to make it constant. The method includes the steps of: detecting angular velocity signals by means of angular velocity detecting device disposed on an axis of the photoreceptor drum; finding deviations from a reference angular velocity, based on the angular velocity signals; storing a profile of the deviations within a one-revolution of the photoreceptor drum in a storage section, while revising the profile in real-time base; applying an arithmetic processing to an angular velocity signal detected at a current rotational-position of the photoreceptor drum by referring data included in the profile obtained in a preceding one-revolution of the photoreceptor drum; and controlling the motor, based on results of the arithmetic processing for the angular velocity signals, so as to compress the deviations from the reference angular velocity as small as possible.

Abstract: A charging device is provided. The charging device comprises a charging member having two spacers made of tape, and the charging member is pressed to contact with the non-image forming region of an image supporter. The surface of the charging member between the spacers is opposite to the surface of the image supporter by a tiny gap. A charging voltage is then applied to the charging member to charge the image supporter. As the image supporter rotates, a large variation of the tiny gap can be avoided. The pressing force of the spacers against the image supporter is set at 4 N to 25 N (Newton), and in a moving direction of the surface of the supporter, a contact width of a contact portion where the spacer is pressed to contact with the image supporter is set below 0.5 mm.

Abstract: An image forming apparatus includes a transferring device for transferring, after a first color developer image is transferred onto an image receiving material in a first image forming station, a second color developer image onto the image receiving material in a second image forming station. A second developer carrying member of the second image forming station is capable of collecting a residual developer from a second image bearing member of the second image forming station simultaneously with a developing operation thereto. The moving direction of the second developer carrying member is opposite to a moving direction of the second image bearing member at a development position. A second charging device of the second image forming station includes a second charging member contactable to the second image bearing member, and the second charging member triboelectrically charges the residual developer on the second image bearing member to a regular polarity.

Abstract: An image forming device includes an image forming unit and a thermal fixing unit. The image forming unit uses a plurality of different color developing agents to form a color image on a recording medium. The plurality of different color developing agents are configured from binding resins with the same thermal properties. The plurality of different color developing agents include at least a high-resistance developing agent and a low-resistance developing agent. The high-resistance developing agent has a higher electrical resistance than the low-resistance developing agent and a lower charge-to-mass ratio than the low-resistance developing agent. The thermal fixing unit thermally fixes the color image onto the recording medium.

Abstract: An image forming apparatus includes a recording sheet type detection device to automatically detect a type of a recording sheet. A setting device sets an image forming condition by an operator. The image forming condition includes the type of the recording sheet. An image forming device forms a visible image on the recording sheet. A sheet feeding device feeds the recording sheet to the image forming device. A controller controls the image forming apparatus not to form an image on the recording sheet when the image forming condition with regard to the type of the recording sheet set by the operator does not match the type of the recording sheet detected by the recording sheet type detection device.

Abstract: An image forming apparatus includes an image bearing member; a developing device for developing a latent image formed on the image bearing member, the image bearing member and the developing means being detachably mountable to the apparatus as a process unit; a developer supply unit for supplying a developer to the developing means, the developer supply unit being detachably mountable to the apparatus; and a first memory mounted on the process unit. The first memory stores information relating to the developer supply unit.