Abstract: An image forming apparatus includes an image bearing member; a transferring member for transferring a toner image from the image bearing member onto a recording material at a transfer portion; voltage applying means for applying a voltage to the transferring member; wherein the voltage applying means is capable of applying to the transferring member a first voltage, a second voltage higher than the first voltage and a third voltage higher than the second voltage; wherein the voltage applying means applies the first voltage to the transferring member, then the second voltage prior to the recording material reaching the transfer portion, and then the third voltage after the recording material reaching the transfer portion.

Abstract: A copy machine having a high accuracy sheet registration system for precise placement of images on each copy sheet. The copy machine includes sensors with charge coupled devices (CCDs) that detect the sheet positions in two dimensions within the machine, and detect sheet arrival times at various positions with the machine. Using this detected information, the copy machine employs a multi-stage process to bring the sheet into contact with a color image moving on a photoreceptor belt, in synchronism with the position and speed of the image on the belt. The copy machine also monitors its own condition and makes predictions about needed preventive maintenance, to instruct personnel to service the machine before the machine fails.

Abstract: An improved printing apparatus provides for very accurate synchronization between cut sheet print media and the unfixed image which is conveyed on an Intermediate Transfer Member (ITM) such as a belt or a drum, and which is targeted for said print media. The printing apparatus is constructed as a single-pass ITM-based electrophotographic (e.g., laser) printer, and the length of the input print media pathway prior to image-to-media transfer is significantly shorter than the sum of the lengths of the image travel along a photoconductive drum and ITM. The print media is typically launched after imaging has been initiated on the photoconductive drum by an imaging apparatus. Variance in the leading edge of the print media with respect to the leading edge of image can be introduced due to phenomena such as pick errors, velocity variation, and uncertainties in the paper stack height.

Abstract: An image forming apparatus includes image forming portion for forming an image on a sheet, separating and feeding portion for feeding sheets stacked on sheet supporting portion one by one toward the image forming portion, sheet conveying portion for conveying the sheets fed by the separating and feeding portion, registration rollers of a variable rotating speed disposed upstream of the image forming portion with respect to a sheet conveying direction, and sheet conveyance controlling portion for causing the registration rollers to effect the conveyance of the sheets at a speed higher than the image forming speed in the image forming portion, and thereafter decelerating the registration rollers so as to assume substantially the same speed as the image forming speed at timing earlier than the latest image forming timing in the image forming portion.

Abstract: To make it possible to transfer an image to an exact position even on a sheet of a maximum size having cutoff margins around a maximum image area of the image-forming module, the invention provides a sheet transport device (5) comprising a registration/transport member (2) provided in a sheet path upstream of a target location (P) for correctly positioning a sheet (1) in a sheet transport direction and transporting it toward the target location (P), and a sheet alignment mechanism (3) provided in the sheet path upstream of the target location (P) for moving the sheet (1) in a direction perpendicular to the sheet transport direction to align the sheet (1) to a reference position predefined for each set of sheet information. The invention also provides an image-forming apparatus incorporating the sheet transport device (5).

Abstract: An image forming apparatus capable of realizing an improvement in terms of apparatus size and productivity and obtaining a satisfactory image includes a conveyance driving motor M1 for driving conveyance roller pairs 41, 42, and 43, a pre-registration conveyance roller pair 44, and a registration roller pair 10; an image formation driving source for driving photosensitive drums 1a, 1b, 1c, and 1d; and a control unit for controlling the conveyance driving motor M1 and the image formation driving source such that the speed at which a sheet material is conveyed by the conveyance roller pairs 41, 42, and 43, and the pre-registration conveyance roller pair 44 is variable, and that the speed at which the sheet material is conveyed by the registration roller pair 10 is substantially the same as the speed at which the sheet material is conveyed by an image forming device.

Abstract: An image forming apparatus includes: a writing device for writing an image on the basis of image data thereof; a controller for controlling a writing position in a primary scanning direction by the writing device; a conveying device for conveying a recording material; and a position detecting sensor for detecting an edge of the recording material, which is conveyed by the conveying device in the primary scanning direction as an absolute position. The controller determines the writing position in the primary scanning direction by the writing device on the basis of a position of the edge of the recording material in the primary scanning direction detected by the position detecting sensor, and controls the writing position of the writing device in the primary scanning direction.

Abstract: An image forming apparatus has: an image memory for storing image data; an image recording device having an image recording position for recording an image onto a recording material at the image recording position; a conveying device for conveying the recording material to the image recording position; and an image correction device for correcting an angle of the image data in accordance with inclination of the recording material conveyed to the image recording position. An image is recorded on the recording material by the image recording device on the basis of the image data corrected by the image correction device.

Abstract: Referring to the table of the count values corresponding to the aligning speeds stored in a ROM, the main control unit sets an aligning speed value (Kd: default value) in the aligning motor speed control circuit 193 and calculates the equation K1=Kd/(−Ta/Tb+(2+&agr;))−1 measured by the aligning speed adjustment sequence and a new target value Ka=(Kd+K1)/2+C. At this time, if |Kd−K1|≦10, the main control unit substitutes C=0; if 20≧|Kd−K1|>10, it substitutes C=2 when Kd<K1 and C=−2 when Kd>K1; and if |Kd−K1|>20, it substitutes C=4 when Kd<K1 and C=−8 when Kd>K1.

Abstract: An image forming device includes a plurality of recording medium supply units, an offset amount memory, and a timing control unit. The recording medium supply units supply recording media. The offset amount memory stores an offset amount for each recording medium supply unit. Each offset amount is for compensating for positional shift in a recording medium supplied from a corresponding recording medium supply unit. The timing control unit retrieves, from offset amount memory, an offset amount corresponding to a presently used recording medium supply unit and performs image forming operations at a timing corrected by the retrieved offset amount.

Abstract: A method of minimizing error in an estimate of a position of a sheet of print medium in an electrophotographic machine includes providing a transport system including a gearing system to drive a roll for moving the sheet of print medium along a print medium path. The gears are in constant mesh with each other and with an actuator. The electrophotographic machine is provided with a toner transfer point at which the toner can be transferred to the moving sheet of print medium. A sensor is placed at a set distance away from the transfer nip along the print medium path. This distance is approximately equal to an integer multiple of the resulting distance traveled by the medium during one revolution of the lowest frequency component of the transport system. The frequencies associated with all other components in the transport system, including the actuator and an encoder wheel, are designed to be an integer multiple of this lowest frequency.

Abstract: A method of media-to-image registration sets a top writing line margin on a print medium within an electrophotographic machine. Movement of a substantially stationary sheet of print medium along a print medium path within the electrophotographic machine is initiated. An image associated with the sheet of print medium is scanned onto a developing unit. The scanning step commences before the initiating step. Toner is adhered to the image on the developing unit. The toner is transferred from the developing unit to a moving toner transfer medium. The electrophotographic machine is provided with a toner transfer area in which the toner can be transferred to the moving sheet of print medium. A speed of the movement of the sheet of print medium is adjusted such that the toner is transferred from the moving toner transfer medium to a desired area on the sheet of print medium within the toner transfer area.

Abstract: A sheet conveying apparatus is provided with a sheet feeding device for feeding sheets from a sheet supporting device on which the sheets are supported, a first sheet conveying device, a second sheet conveying device and a third sheet conveying device successively disposed downstream of the sheet supporting device with respect to the feeding direction of the sheets for conveying the sheets, a sheet interval judging device for detecting the passage of the sheets between the second sheet conveying device and the third sheet conveying device, and judging whether the interval between the sheets is a predetermined interval, and control device for controlling the sheet feeding device, the first sheet conveying device and the second sheet conveying device so that the sheets can be conveyed at the predetermined interval on the basis of the judgement of the sheet interval judging device.

Abstract: An image forming apparatus of an electrophotographic type including a paper feeding device for separating and feeding piled recording paper, an image forming device for forming the image in order on the fed recording paper, a paper turning-over device for switching back the recording paper and turning over the front and rear tip ends of the recording paper, and a paper re-feeding device for re-feeding the recording paper having the image on one-side surface. In such an apparatus, the both-surfaces image formation can be practiced at the same paper distance, keeping the image forming apparatus small in size and low cost. Furthermore, a conveying roller for switching back the paper and sending out the paper to a printer engine is provided such that the rear tip end of the paper accommodated in the switching-back path becomes the front tip end thereof, and a jogger for performing compensation of lateral registration for the paper is provided in the switch-back path.

Abstract: An image forming apparatus includes a plurality of sheet feed units each for feeding a sheet, a single pair of registration rollers provided at the upstream side of the image formation site where an image is formed on the sheet with respect to the direction of sheet conveyance, for conveying the sheet in accordance with the timing of forming the image on the sheet, and a plurality pair of loop forming rollers provided in correspondence with the plurality of sheet feed units respectively at the upstream side of the pair of registration rollers with respect to the direction of sheet conveyance. Each of the plurality pair of loop forming rollers is controlled in a manner such that a loop is formed between each of the plurality pair of loop forming rollers and the pair of registration rollers.

Abstract: In an electrophotographic printing apparatus, when the conveying speed of the timing roller (1a, 1b) is Vt, the conveying speed of the register roller (2a, 2b) is Vr, the peripheral speed of the photoreceptor drum (3) is V0, and the conveying speed of the conveying apparatus (5) is Vf, each speed is set to satisfy the relationship of Vf>V0≧Vr>Vt, and when a sheet deflection amount formed when the sheet comes into contact with the register roller, is &dgr;r, the sheet deflection amount at the photoreceptor drum entry section is &dgr;0, and the sheet length is Lp, each value is regulated so that the relationships of &dgr;r≧Lp ((Vr−Vt)/Vt) and &dgr;0≧Lp ((Vf−V0)/V0) are satisfied.

Abstract: An image-forming device such as a full color printer is provided which is designed to correct the speed of a conveyer belt on which print sheets are transported or intervals between image-transferring units for compensating for a shift between colors. The image-forming device has a timer which measures an elapsed time from turning on of the device or release of a sleep mode, a print-off time and a print time and determines a correction value as a function of the times measured by the timer by look-up using a table.

Abstract: A paper supply controlling apparatus in a printer and a paper supply method are provided. The paper supply controlling apparatus includes a pickup roller for picking up sheets of paper loaded in a paper feeding cassette, a pickup roller driving portion for driving the pickup roller, a recognition pattern detecting sensor for detecting passage of a recognition pattern formed on a circulating photoreceptor belt and outputting a recognition pattern arrival signal, and a paper pickup timing correction portion for determining a variation in the circulation cycle of the photoreceptor belt from the generation interval between the recognition pattern arrival signals, and controlling the pickup roller driving portion so that the time for picking up a sheet of paper from the paper feeding cassette on the basis of the time when the recognition pattern arrival signal is received is compensated for using the variation.

Abstract: An electrophotographic apparatus including a photosensitive member; a corona charger for charging a surface of the photosensitive member; a circuit-forming/chargeable powder supplying device for supplying circuit-forming/chargeable powder to a latent image pattern on the photosensitive member; a transferring device for transferring the circuit-forming/chargeable powder on the latent image pattern onto a ceramic green sheet; a flash lamp for fixing the circuit-forming/chargeable powder, transferred onto the ceramic green sheet, in order to form a circuit pattern (not shown) on the ceramic green sheet; and a circuit pattern forming position recognizing camera for detecting a circuit pattern forming position on the ceramic green sheet. In the electrophotographic apparatus, laser beams are used to form a predetermined latent image pattern (not shown) on a surface of the photosensitive member.

Abstract: The apparatus includes an endless belt, an imaging station, a number of developing stations, and a number of transfer stations. A controllable belt drive drives the endless belt along a path through the imaging station, the developing stations and the transfer stations. A preformed timing mark is carried on the belt and a sensor is provided for sensing the passage of the timing mark past a sensing position. A control device controls the belt drive to run at a constant speed and controls the speed of the belt in response to the sensing of the timing mark. The maintenance of a constant belt speed can be more reliably assured.

Abstract: An apparatus and method for correcting top edge sheet misregistration using a sensor array. An array sensor is placed in the paper path prior to transfer. A signal is generated indicating the position of the sheet. As a function of the signal the print controller causes the image to be exposed and developed on the photoreceptor in alignment with the sheet position. The aligned image is then transferred to the sheet.

Abstract: An image forming apparatus is provided with a developer for developing a latent image on a photoreceptor drum into a visible image and a transfer drum having a position detector, for holding a supplied transfer material at a predetermined position and conveying the transfer material, and a transfer voltage source for supplying a transfer voltage to a conductive base of the transfer drum and output values of the transfer voltage source vary in stages when toners of a plurality of colors are transferred. In the image forming apparatus, when printing is continuously performed on a plurality of transfer materials, the timing where output values of the transfer voltage source are returned to the initial value is synchronized with the timing where the rear end of a transfer material having a maximum length capable of being printed is separated from the photoreceptor drum. As a result, the transfer material attracted by the transfer drum can be surely prevented from being jammed.

Abstract: A method of aligning duplex images on an imaging device such as a printer or copier includes duplex imaging a test sheet having indicia on each side of the sheet that communicate, when observed in a single visual context, duplex imaging adjustment parameters for the imaging device. The method further includes modifying imaging parameters of the imaging device based on the duplex imaging adjustment parameters communicated. The indicia on each side of the sheet are seen in a single visual context by observing certain of the indicia through the media, as when the media is held up to a light source. In a preferred embodiment, the indicia on each side of the sheet includes respective portions of a vernier scale. The imaging parameters are modified by entering the adjustment parameters at a control panel of the imaging device. Imaging parameters modified include timing parameters associated with the process of writing data on the imaging device.

Abstract: An image forming apparatus for forming an image on a recording material. The position of the recording material is detected when the recording material is underway from a registration roller for correcting a skew of the recording material to an image forming position for the recording material, and the image is written based on the detected position signal. The image is thus formed at a proper position on the recording material.

Abstract: There is described an image forming apparatus to form an image on a transfer sheet, in which an image bearing member, image exposing unit for forming a latent image, developing unit for developing the latent image, an intermediate image bearing member for bearing a toner image on its surface, first transfer member for transferring the toner image from the image bearing member to the intermediate image bearing member or the first side of the transfer sheet, second transfer member for transferring said toner image from the intermediate image bearing member to the second side of the transfer sheet, fixing unit for fixing the toner images on the both sides of the transfer sheet, detector for detecting a reference position on the intermediate image bearing member, and controller for controlling timing to start forming the latent image and/or timing to feed the transfer sheet to the first transfer member on the basis of the detection of the reference position on the intermediate image bearing member, are. included.

Abstract: An image forming apparatus includes a recording sheet feeding member which feeds a recording sheet on a feed tray to a transporting path, an endless recording sheet transporting member having an inappropriate portion which is not suitable for use in forming an image, a transporting member which transports the recording sheet fed from the recording sheet feeding member to the recording sheet transporting member, and an inappropriate portion detector which detects an inappropriate portion on the recording sheet transporting member. A controller controls the transporting member such that the recording sheet is fed so as to avoid the inappropriate portion based on a result detected by the inappropriate portion detector.

Abstract: An image formation system includes: a paper transport unit transporting paper along a paper transport passage; an image formation unit forming an image on an image carry belt; an image sense unit sensing a position of the image formed on the image carry belt; a transfer unit transferring the image formed on the image carry belt to the paper transported by the paper transport unit; a paper passage sense unit sensing paper passage on the paper transport passage, the paper passage sense unit being disposed upstream from a position where the image is transferred by the transfer unit; and a control unit controlling paper transport speed of the paper transport unit based on the sense results of the image sense unit and the paper passage sense unit.

Abstract: An image forming apparatus which forms toner images of different colors by at least one image forming device with a rotatably driven image bearing member, and forms a picture by transferring the different colored toner images formed by the image forming device onto an image transfer medium supported on a rotatably driven endless bearing member, or directly onto the endless bearing member,the image forming apparatus wherein a latent image writing position on the image bearing member being angularly spaced by approximately 180.degree.

Abstract: An image forming apparatus includes an image transfer unit disposed along a sheet feed path. A sheet feed roller feeds a sheet toward an image transfer position where an image can be transferred by the image transfer unit. A sheet detect unit detects the sheet fed by the sheet feed roller and a control unit controls the rotational operation of the sheet feed roller in accordance with a detection result of the sheet detect unit. As such, a sheet feed path length, which extends between the image transfer position and a detection position where the sheet is detected by the sheet detect unit, is set at an integer multiple of a circumferential length of the sheet feed roller.

Abstract: A printing system for printing multiple colors on a sheet of print media includes an electrophotographic printer having a photoconductor drum and a transfer roller configured to interact in co-rotation with the drum during transfer of a color image plane from the drum onto a sheet of print media passed therebetween. A paper drive sheet feeder system is included which has a grit shaft extending generally transverse of a paper travel path, a first pinch roller configured to interact in co-rotation with the grit shaft along a first edge of a sheet of print media, and a second pinch roller configured to interact in co-rotation with the grit shaft along a second edge of the sheet of print media. The grit shaft is driven in rotation to drive the sheet of print media along a bidirectional sheet travel path such that a plurality of different colored image planes is superposed onto the sheet of print media in accurate registration therebetween. A method for printing multiple colors is also described.

Abstract: An image-forming machine comprises a sheet member conveying passage extending through a transfer zone and a fixing zone, a sheet member-feeding means for feeding a sheet member onto the sheet member conveying passage, and a sheet member conveying means for conveying the sheet member through the sheet member conveying passage. A housing of the image-forming machine has a lower surface defined by an intermediate lower wall and an upper surface defined by an intermediate upper wall, and forms a space of which the front surface is opened. The downstream end portion of the sheet member conveying passage extends along a one side portion of the intermediate lower wall on the lower side thereof. The one side portion of the intermediate lower wall is defined by the opening/closing member, and opening/closing member is brought to the open position to open the downstream end portion of the sheet member conveying passage. The sheet member conveying means includes a pair of register rollers.

Abstract: A copy media registration module for positioning paper in a feed path is disclosed. More specifically, the present invention is directed to a module for registering copy media on an imaging member that lies at the end of a paper path, where the registration module can be removed from and replaced into a machine as a single unit. In addition, enhancements can be added to the module to provide for even more accurate copy media registration and greater media substrate latitude as desired. The modular nature of the registration module allows diagnostic testing as well as repairs and/or periodic maintenance to be easily conducted on the unit outside of the machine in which it is typically used. It also provides easy replacement of the unit if it is no longer functional, or for a temporary unit to be used while the permanent unit is being repaired.

Abstract: A sensor for measuring a temperature of a portion near an exposing unit to expose a photosensitive drum and a sensor for measuring a temperature in an apparatus other than the exposing unit are provided, thereby controlling a registration correction operation in accordance with a difference between outputs of those sensors. Thus, the registration correction operation can be always executed at the optimum timing and a good image can be continuously formed.

Abstract: An image forming apparatus improved so that the leading end of a sheet can be exactly stopped in a nip position of registration rollers, and an image transferred to the sheet is not shifted. A locking device is provided in relation to the registration rollers provided in a conveying path. When the leading end of a cut sheet is inserted into the conveying path and is fed to the registration rollers, the registration rollers are brought into a state where it cannot be rotated by the locking device. Therefore, the leading end of the cut sheet fed is reliably stopped in the nip position of the registration rollers, and cannot enter the conveying path beyond this position. The conveyance of the cut sheet is thereafter resumed by the registration rollers and reaches a downstream pair of conveying rollers where the sheet is subjected to so-called secondary sheet feeding to an image forming section.

Abstract: A unique system and method for directly feeding sheets into a printing device having a moving image conducting element with a plurality of images placed thereon for transfer to sheet paper and having a wait station for controlling the timing of paper transfer to the image conducting element provides a feeding table to transfer sheets from a source to a printer stack deshingler while bypassing and, thus, eliminating any need for sheet stacks. The movement of each sheet by the wait station into the image transfer element signals the cutting of a sheet from a roll of continuous web on the input side of the feeding table. Once the sheet has moved into the image transfer element the absence of a sheet at the detector signals transfer by the feeding table of the cut sheet to the stack deshingler. Simultaneously, a source of web presents and end of the web representing another sheet to a cutting unit. This sheet is cut when the current sheet at the wait station begins movement into the image transfer element.

Abstract: A sheet guide mechanism is provided with a guide path along which a sheet-like member is guided and which is defined between one and the other guide surfaces. A stationary guide member has a first surface defining the one guide surface, and a movable guide member having a second surface defines the other guide surface, which is shiftable relative to the stationary guide member. Protrusions are formed on one of the first and second surfaces, protruding toward the other of the first and second surfaces by a predetermined distance. A shiftable member is shiftable relative to the stationary guide member between a guide position and a remote position. A spring is provided between the shiftable member and the movable guide member allowing the elastic contact between the protrusions and the other of the first and second surfaces, when the shiftable member is located in the guide position.

Abstract: An image forming apparatus includes: medium transporting belt that carried an image recording medium on its surface, and is driven so that the surface is circulatively turned; a plural number of toner image forming drums facing the transporting belt, each including an image bearing surface having an electrostatic latent image formed thereon, a developing unit for developing the electrostatic latent image into a toner image, and an image transferring unit for transferring the toner image on the transporting belt or an image recording medium held on the transporting belt; medium supplying trays and path for successively supplying image recording media to the transporting belt; a medium attracting electrode facing the transporting belt; a counter electrode opposing to the medium attracting electrode with respect to the medium attracting electrode; an electric field formed between the medium attracting and counter electrodes to cause the transporting belt to attract the image recording medium to the transporting

Abstract: A solenoid-controlled sheet registration mechanism for a copier/printer includes registration fingers for registering the lead edge of a sheet before it is fed to the transfer station of the copier/printer, to receive a developed image from the photoreceptor. The mechanism also includes a pair of nip rolls for forwarding the sheet to the transfer station, after registration. Energization of the solenoid moves the registration fingers into the registration position and disengages the nip rolls. Conversely, release of the solenoid allows the registration fingers to return to a non-registration position and the nip rolls to return to paper-feeding engagement, both of those return movements taking place under a resilient bias. To soften the impact between the nip rolls as they re-engage, and so reduce any resulting noise, the release of the solenoid is controlled by applying a pulsed drive signal to the solenoid during the release period after the energizing signal has ceased.