Abstract: An optical wavelength grating coupler incorporating one or more distributed Bragg reflectors (DBR) or other reflective elements to enhance the coupling efficiency thereof. The grating coupler has a grating comprising a plurality of scattering elements adapted to scatter light along a portion of an optical path, and the one or more DBRs are positioned with respect to the grating such that light passing through the grating towards the substrate of the grating coupler is reflected back by DBRs toward the grating. The DBR comprises a multilayer stack of various materials and may be formed on the substrate of the grating coupler. The grating coupler may include a gas-filled cavity, where the cavity is formed by a conventional etching process and is used to reflect light toward the grating. The grating coupler may also incorporate an anti-reflection coating to reduce reflective loss on the surface of the grating.

Abstract: An optical module comprising a column-shaped mounting member having a through hole extending along the central axis thereof and having a mounting surface formed by incising a part of the mounting member so as to expose the interior surface of the through hole; and an optical fiber inserted in the through hole and secured in a configuration such that the optical fiber protrudes with a specified length onto the mounting surface. The structure, in which a Bragg diffraction grating is formed in such protruding part of the optical fiber on said mounting surface, can prevent the occurrence of a change in reflective characteristic of the Bragg diffraction grating.

Abstract: An optical microresonator includes microcylinder and spiral resonant waveguide formed on the microcylinder that optically couples light from an optical source waveguide to the microcylinder and slows light propagating along the microcylinder. A coupling element, for example, a diffraction grating can be operative with the resonant waveguide structure and configured to meet a desired phase matching. A second microcylinder having a spiral resonant waveguide formed thereon can be positioned adjacent to the spiral resonant waveguide formed on the first microcylinder for coupling therewith. The spiral resonant waveguides on first and second microcylinders can be configured for slowing light propagating along the microcylinder.

Abstract: The present invention relates to an optical coupling module for optically coupling an optical fiber with an optical waveguide, and a method of fabricating the optical coupling module. In an optical coupling module for optically coupling an optical network with a planar lightwave circuit (PLC), an etched groove for disposition of the optical fiber and an etched groove for mounting of the optical waveguide are exposed using a mask having mask patterns that are aligned with each other, and then anisotropically etched. By doing so, the two grooves can be precisely aligned with each other at one time, compared with a conventional method in which an exposure process is carried out two or more times. Accordingly, an inexpensive structure having high optical coupling efficiency upon manual alignment can be obtained.

Abstract: An optical device includes an optical input waveguide, a branch/cross waveguide, an optical output waveguide and connection waveguides that connect the optical input and optical output waveguides to the cross/branch waveguide. The spot size of light propagating through the cross/branch waveguide is larger than the spot size of light propagating through optical input waveguides, the optical output waveguides, or the connection waveguides.

Abstract: Ring or disc optical resonators are provided with random or coherent corrugation on a top surface to cause optical power to be radiated in a desired direction by light scattering. The resonators may be positioned proximate a waveguide, either in-plane or inter-plane with the waveguide. The resonators are used in a polymeric photonic display. Light at each fundamental color is generated by light emitting diodes, such as organic light emitting diodes (OLEDs). The light is coupled into waveguides that cross an array of diffractive elements, such as the resonators, each combined with an optical modulator, such as a polymer electro-optic (EO) modulator. The modulator allows light from the waveguides to reach the diffractive elements. Control lines run across the waveguides, and provide control signals to the modulators, allowing one row of diffractive elements at a time to receive light from the waveguides. The rows are scanned and synchronized with light generated by the OLEDs.

Abstract: A factory-manufactured, preterminated fiber optic distribution cable having at least one predetermined access location for providing access to at least one preterminated optical fiber. A preterminated fiber optic distribution cable comprising at least one buffer tube comprising at least one optical fiber, a buffer tube transition piece operable for transitioning the at least one optical fiber from the at least one buffer tube into at least one protective tube, a C-shaped molded member defining a longitudinally extending optical fiber guide channel operable for storing a length of the at least one preterminated optical fiber and a protective means. A method of mid-span accessing at least one optical fiber from a fiber optic distribution cable. A buffer tube transition piece operable for transitioning a plurality of preterminated optical fibers from a buffer tube into protective tubing.

Abstract: A fiber optic drop cable including at least one optical waveguide, at least one roving, and a cable jacket. In one embodiment, the at least one roving includes a resin matrix having a water-based acrylic composition that includes an ethylene-acrylic acid and a water-swellable component. The resin matrix has a percent by weight of about 10 percent or less of the flexible roving so that the at least of one roving is at least partially bonded with the cable jacket, thereby inhibiting buckling of the cable jacket. In another embodiment, a plurality of rovings are arranged in clusters in the cable for influencing the bonding between the rovings and cable jacket. Also, disclosed is a protective casing for protecting and routing optical fibers along with preconnectorized cable assemblies.

Abstract: A fiber optic ribbon cable includes: a plurality of substantially parallel optical fibers formed into a ribbon, the ribbon extending in a longitudinal direction and having first and second ends; and a termination assembly attached at each of the first and second ends of the ribbon. Each of the termination assemblies includes a body and a ferrule, the body having a key on an upper surface thereof. The ferrule has a polished contact surface that exposes ends of the optical fibers; the contact surface forms an oblique angle relative to a plane normal to axes defined by the fibers. The termination assemblies at the first and second ends of the ribbon either both face slightly upwardly or both face slightly downwardly.

Abstract: A method of manufacturing a glassy optical preform is disclosed that includes providing a preform having a silica soot layer and then sintering the soot layer into a glassy layer, and water is selectively added to the preform by exposing the soot layer to a gaseous water-containing atmosphere during the sintering step. The preform is controllably doped with water.

Abstract: The invention relates to a micro-structured fiber comprising a core region and a cladding region. The cladding region has a plurality of air holes regularly arranged on a plurality of rings, wherein the innermost ring of the fiber defines the core region. The cladding region comprises an inner circumference portion and an outer circumference portion; the inner circumference portion comprises at least one ring, the outer circumference portion comprises at least one ring, wherein the diameter of the air hole on the outer circumference portion is larger than that of the air hole on the inner circumference portion. As a result, the micro-structured fiber of the present invention has the advantages of broader band of nearly zero dispersion, less confinement loss, being easier to design due to less geometrical parameters needed to be optimized, and being easier to fabricate.

Abstract: The present invention aims to provide an electromagnetic wave frequency filter capable of transmitting an electromagnetic wave having a predetermined frequency between two waveguides with a high level of efficiency. This object is achieved by the following construction: A resonator 15 that resonates with the electromagnetic wave having the predetermined frequency is located between an input waveguide 13 and an output waveguide 14 and close to the two waveguides. The output waveguide 14 is designed so that it extends parallel to the input waveguide 13 within a predetermined section 18 located in proximity to the resonator 15, and its distance from the input waveguide 13 in the other section is larger than that in the predetermined section 18.

Abstract: A slab-type photonic crystal arranged to reduce the coupling loss in coupling to an optical fiber and to satisfy single-mode conditions. The photonic crystal has a slab having a plurality of slab refractive index portions and vacancies formed between the slab refractive index portions. The number, shape, size and refractive index of the slab refractive index portions and the number and shape of the vacancies are selected so that when a beam of light entering the waveguide expands to a maximum extent, the size of the beam in the slab thickness direction does not exceed the slab thickness.

Abstract: The device is an optoelectronic device or transparent waveguide device that comprises a growth surface, a growth mask, an optical waveguide core mesa and a cladding layer. The growth mask is located on the semiconductor surface and defines an elongate growth window. The optical waveguide core mesa is located in the growth window and has a trapezoidal cross-sectional shape. The cladding layer covers the optical waveguide core mesa and extends over at least part of the growth mask. Such devices are fabricated by providing a wafer comprising a growth surface, growing an optical waveguide core mesa on the growth surface by micro-selective area growth at a first growth temperature and covering the optical waveguide core mesa with cladding material at a second growth temperature, lower than the first growth temperature.

Abstract: A new class of surface plasmon waveguides is presented. The basis of these structures is the presence of surface plasmon modes, supported on the interfaces between the dielectric regions and the flat unpatterned surface of a bulk metallic substrate. The waveguides discussed here are promising to have significant applications in the field of nanophotonics by being able to simultaneously shrink length, time and energy scales, allowing for easy coupling over their entire bandwidth of operation, and exhibiting minimal absorption losses limited only by the intrinsic loss of the metallic substrate. These principles can be used for many frequency regimes (from GHz and lower, all the way to optical).

Abstract: A three-dimensional photonic crystal operating at a plurality of design wavelengths, in which the photonic band gap can be adjusted to a desired wavelength band without changing the lattice period, and an optical element that can contain a defect resonator or a defect waveguide in the three-dimensional photonic crystal are provided.

Abstract: A multiple-core planar optical waveguide comprises: a substantially planar waveguide substrate; a lower waveguide core; an upper waveguide core; lower cladding between the substrate and the lower waveguide core; and upper cladding above the upper waveguide core. At least a portion the upper waveguide core is positioned above and substantially parallel to at least a portion of the lower waveguide core. The lower and upper claddings have refractive indices less than refractive indices of the lower and upper waveguide cores. The width of the lower waveguide core is substantially larger than its thickness along at least a portion of its length, and is substantially flat along that portion of its length, thereby yielding a substantially flat surface for forming at least a portion of the upper waveguide core.

Abstract: A cable exit trough with pivoting cover. The cover having a cover plate and a pivot plate hingedly mounted thereto for easy access to the trough. The exit trough may define an insert aperture for receiving modular cable management inserts. The modular insert providing an additional cable management device such as a curved guidewall. The cable management device may alternatively be fixed to the cable exit trough. Removable snap-mounted flanges may also be included in the exit trough.

Abstract: A separator for an optical-fiber tape, the optical-fiber tape including a group of optical-fibers extending in parallel with each other, the separator including a supporting member configured to support a length of the optical-fiber tape along a first lateral edge thereof, a positioner configured to apply a resilient force to the length of the optical fiber tape along a second lateral edge thereof, wherein the first lateral edge and second lateral edge are on opposite sides of the optical fiber tape; and a separation member configured to separate a first portion of the length of the optical-fiber tape by shearing the optical-fiber tape along the direction of extension of the group of optical fibers.

Abstract: A multi-source optical module is described that includes an optical circuit positioned on a base. The optical circuit includes a first and a second optical input. A first and a second optical source are positioned on the base relative to the optical circuit. A first lens is positioned between an output of the first optical source and a first input of the optical circuit. A second lens is positioned between an output of the second optical source and a second input of the optical circuit. At least one of the first and the second lenses are positionable so that the output of a respective one of the first and second optical sources and a respective one of the first and the second optical inputs of the optical circuit are aligned.

Abstract: Information carrier, device for reading and device for providing the information carrier and method of transmitting picture information. The disclosed system comprises an information carrier (1) on which an information signal is recorded that represents picture information intended for being displayed on a picture screen, which picture information comprises video information of a video programme as well as control information for selectively displaying the video programme. The video programme is subdivided into sections (35) and, when the video programme is displayed selectively, sections are shown in a new order (34) and partly omitted or replaced. To this end the control information includes path information (36) which indicates a path of sections to be displayed in linked fashion. The path information may be recorded multiplexed with MPEG-2 video information and then contains addresses (53, 54, 55, 56, 57, 58, 59) for forward and backward jumps.

Abstract: A method of recording an encoded bit stream, the encoded bit stream representing a plurality of video objects comprising a sequence of cells together constituting a part of an MPEG2 Program Stream, on a disc like record carrier, such as an optical disc. The method comprising recording video objects comprising a sequence of contiguously recorded cells, each cell comprising a unique cell identification number within a video object, recording a playback sequence of cells defining a playable program chain of cells, wherein the sequence comprises references to the cell identification numbers and recording navigation data within the cells comprising an end time of presentation of the corresponding video object. The method further comprises recording at the end of a video object a dummy cell that is not being referenced by a playback sequence.

Abstract: In a commercial-break detection device (7) for the detection of commercial-break information (WBI) present in picture information (RI) of a television signal (FS), having detection means (8) arranged to receive the television signal (FS) and adapted to detect black-frame information (SBI) in the picture information (BI) of the television signal (FS), and having memory means (9) for the storage of black-frame lime information (SZI) for each one of at least two units of detected black-frame information (SBI), and having analysis means (10) for analyzing the stored black-frame time information (SZI) and for determining commercial-break position information (WP1, WP2) identifying the commercial-break information (WBI) in the picture information (BI), the detection means (8) are now adapted to detect a fade-out (FO), in which fade-out (FO) a luminance signal (Y) of the picture information (BI) decreases during a fade-out time (FT) until the picture information (BI) is formed by the black-frame information (SBI), a

Abstract: An information storage medium capable of recording and playing back still picture information is provided with a first information unit having one still picture information, and a first group unit which is composed of a set of first information units, and has a plurality of pieces of still picture information having different contents. Information is recorded in the first group unit.

Abstract: A storage medium which stores catalog information and a catalog information recording and/or playback apparatus and method therefor. Using the method, catalog information including a still picture and additional information together with audio data are recorded on a storage medium such as a digital versatile disk (DVD), which is an optical record storage medium, and the catalog information is played back during playback of the audio data, to thereby provide various information on the audio data. Also, the apparatus includes a buffer memory for catalog playback which maintains a predetermined standard and compatibility, and is capable of real-time reading during playback of the audio data, and automatically plays back the catalog content, corresponding to the playback state of the audio data, when there is no additional selection of a user.

Abstract: There is provided a digital video recording/reproduction apparatus which can precisely perform a reproduction process while preventing noise generation even when a program has been recorded in overwriting fashion, such being realized by detecting a discontinuous portion in the stream at the time of reproduction. A PMT_PID or an ES_PID contained in each packet of a partial TS is recorded on a recording medium so as to take a different value each time there is a discontinuity in a stream. As a result, in a reproduction process of a recording medium which has been recorded in this manner, especially when data which has been overwritten on an already-recorded medium is to be reproduced, the discontinuous portion in the stream (i.e., the recorded portion immediately following the overwritten portion) can be easily determined. Thus, a precise reproduction process can be performed while preventing noise from being generated.

Abstract: In accordance with certain aspects of the present invention, enhancements have been developed to further extend the performance of the generic DVD navigator component. Of significance herein, was the need to assign a unique identifier to DVD discs and the like. Doing so allows player applications to easily identify, catalogue and associate information with each disc. Previous “unique” ID algorithms have failed to produce useful and reliable identifiers. Thus, improved methods and arrangements are provided for use in the generic DVD navigator that produces substantially, statistically unique disc IDs.

Abstract: In a control apparatus for a motor, which rotates a fan, a semiconductor device is connected to the motor in series to drive the motor. An analog driver circuit drives the semiconductor device with an analog voltage. A PWM control circuit drives the semiconductor device with a PWM signal of a frequency of less than several tens. A switching control circuit selects the analog driver circuit and the PWM control circuit when the motor is to be rotated at speeds lower and higher than a predetermined speed, respectively.

Abstract: A footrest is provided comprising a base portion for placement on a supporting surface, a footplate connected to the base portion for receiving a foot of a user of the footrest, a heater connected to the base portion, an air intake system connected to the heater for drawing a first mass of air into the footrest, and an exhaust connected to the heater for expelling a second mass of air from the footrest. The heater receives the first mass of air, heats it, and expels it as a second mass of air. A warm air shield helps redirect the second mass of air expelled through the exhaust at the foot of the user placed on the footplate. The footplate may be made to pivot with respect to the base portion, or may be provided with a control knob so that a user may control the heater using her foot.

Abstract: An infrared ray lamp having a structure wherein a groove is formed in the vicinity of each of both end portions of a substantially plate heating element formed of a carbon-based substance, a carbon-based adhesive is applied to a region including the groove, and the end portion of the heating element is inserted into a slit formed at the end portion of a heat-emitting block having high conductivity so as to be sandwiched; by forming a reflection film on the glass tube of the infrared ray lamp, an infrared ray lamp having a desired emission intensity distribution is provided; a heating apparatus using this infrared ray lamp and method of producing the infrared ray lamp are also provided.

Abstract: A heating arrangement heats a first major surface of a workpiece with an illumination energy such that a first portion of the illumination energy is directly incident upon the first major surface of the workpiece and a second portion of the illumination energy is directed such that, at least initially, the second portion would miss the first major surface. A reflector, having a central opening, reflects at least some of the second portion of the illumination energy onto the peripheral edge region of the workpiece for preheating compensation. The reflector is configured for shadow-free exposure of a second, opposing major surface of the workpiece to a flash heating energy. A workpiece manipulation arrangement is described to provide for dynamic preheating movement to vary a heating profile across the workpiece and, thereafter, move the workpiece to a flash heating position. Automatic workpiece centering is featured by the manipulation arrangement.

Abstract: In the realm of professional photography, and those amateur wanting professional results, when photographing people, the illumination devices must be located directly above and on the centerline of the camera lens. This is the desired effect as not to have shadows behind the subjects. Changing from landscape to portrait modes, currently requires the re-adjustment of the illumination devices to bring them in line with the camera. In photographing people, the instant does not wait for the photographer to ready his equipment, rather the photographer must be able to adapt quickly. There exists many different kinds illumination devices that are necessary for proper illumination of photographic subjects, in particular people. There also exists cameras that utilize digital imaging technology that senses through the camera lens for exactitudes of distance and amount of ambient light.

Abstract: The present invention relates to a method for the modulation of the signal power in optical transmission systems comprising an optical amplification device. Also a method for the detection of bit errors in the processing of digitalized transmitted data is disclosed whereby the data are transmitted by an optical transmission system.

Abstract: The invention describes methods and systems for monitoring the performance of an optical network by marking a group of optical signals with a set of identification tags which are unique to network characteristics. In the preferred embodiments, fiber identification (FID) and bundle identification (BID) tags are encoded into optical signals by marking an optical signal with low frequency dither tones whose frequencies are unique to the fiber section and to a bundle of fibers respectively. Detecting of the FID and BID tones provides more effective and accurate monitoring of performance of the optical network and allows determining of the network topology, e.g. paths of optical channels and traffic load through different fiber sections in the network. Other sets of hierarchically arranged identifiers encoded into optical signals have also been proposed, including band, conduit, city, region, country, etc. identifiers, as well as identifiers related to network security and service characteristics.

Abstract: According to the invention, in a transmission apparatus, there are provided an equipment supervision unit detecting an obstacle in the equipment and a switching control unit controlling the switching operation of transmission lines. When the equipment supervision unit detects condition in which obstacles have occurred in more than one groups of the cross connect unit or the clock unit in which paths provided are disconnected, the same K-bytes as in the case when SF failure is detected are outputted to all the fibers to be inputted to the equipment. Alternatively, an FS-R command is executed to both sides, or Line-AIS is inserted in all the outputted transmission lines, or an output is disconnected, so that the equipment is isolated and the paths provided through a node is relieved.

Abstract: A two-stage switching network that takes data from an input and first switches it through a space stage into a buffer. Data from the buffer is then switched in a time-space stage to an output. Each buffer, advantageously, holds one frame of data. Further, there are two buffers such that one may be filled from the input while the other is emptied to the output, and vice-versa. A maximum amount of data may be switched in space and time regardless of its origin and destination, effecting a switching network that is capable of the widest SONET-specified bandwidth.

Abstract: An optical network includes an optical ring and a plurality of add/drop nodes coupled to the optical ring. Each of the add/drop nodes is operable to passively add and drop one or more traffic streams to and from the optical ring, and each traffic stream comprises a channel. A hub node also coupled to the optical ring is operable to selectively pass and terminate individual traffic streams.

Abstract: A return path system includes inserting RF packets between regular upstream data packets, where the data packets are generated by communication devices such as a computer or internet telephone. The RF packets can be derived from analog RF signals that are produced by legacy video service terminals. In this way, the present invention can provide an RF return path for legacy terminals that shares a return path for regular data packets in an optical network architecture. The invention operates independently of a legacy upstream transmission timing scheme so that the legacy upstream transmission timing scheme can remain effective in preventing data collisions. In other embodiments, the present invention allows for less complex hardware for subscribers that are not taking data services. Further, an optical signal present line in combination with a driver may be employed in order to reduce the amount of hardware in a laser transceiver node.

Abstract: A chromatic dispersion compensator in a single-pass and a double-pass version is disclosed. In a single-pass version, the compensator has a diffractive grating for spatially separating an input optical signal into spatially spaced frequency components and a MEMS array of separate phase shifters, each for imparting an independent phase shift to a channel containing a range of the spatially spaced frequency components. In a double-pass version, a retroreflector is disposed to effect a double pass of the light beam through the grating and the phase shifters. The arrangement is effecting in reducing chromatic dispersion of the optical signal.

Abstract: A reconfigurable optical add-drop multiplexer is disclosed including an optical splitter receiving an input optical signal and splitting the input optical signal into a dropped optical signal and an express optical signal; a wavelength blocker optically coupled to the optical splitter, the wavelength blocker blocking particular wavelengths in the express optical signal; a cassette having a plurality of slots capable of accepting a plurality of pluggable optical filters; at least one pluggable optical filter optically coupled to the optical splitter, the pluggable optical filter filtering wavelengths so as to output a particular wavelength channel from the dropped optical signal; and an optical combiner optically coupled to the wavelength blocker and to an optical add path on which an optical add signal may be carried, the optical combiner combining the express optical signal having particular wavelengths expressed by the wavelength blocker and the optical add signal.

Abstract: Disclosed are a device and method of powering down an optical transceiver coupled to an optical transmission medium. A data transceiver may be coupled to transmit data between the optical transceiver and a media independent interface (MII). The data transceiver comprises logic to power down at least a portion of the optical transceiver in response to detection of a power down condition.

Abstract: A single-chip integrated circuit, sometimes called a controller, controls operation of a transceiver having a laser transmitter and a photodiode receiver. The controller includes memory for storing information related to the transceiver, and analog to digital conversion circuitry for receiving a plurality of analog signals from the laser transmitter and photodiode receiver, converting the received analog signals into digital values, and storing the digital values in predefined locations within the memory. Comparison logic compares one or more of these digital values with predetermined setpoints, generates flag values based on the comparisons, and stores the flag values in predefined locations within the memory. Control circuitry in the controller shuts off the laser transmitter in response to comparisons of signals with predetermined setpoints that indicate potential eye safety hazards.

Abstract: Optical systems are provided. A representative optical system includes an optical transceiver with an optical source and an optical receiver. The system also includes an optical waveguide. At least one of the optical source and the optical receiver is optically coupled to an intermediate portion of the optical waveguide. The optical source provides optical signals for propagation by the optical waveguide, and the optical receiver receives optical signals propagated by the optical waveguide. Methods, optical transceivers and other systems also are provided.

Abstract: A telemetry system includes a plurality of acoustic sensors for receiving acoustic information and generating analog signals based on the received acoustic information. A first plurality of subsystems is coupled to at least a subset of the plurality of acoustic sensors. The first plurality of subsystems is configured to receive the analog signals from the acoustic sensors and generate digital values based on the received analog signals. The system includes a first optical splitter. A first optical transmitter transmits a first set of optical pulses to the first optical splitter. The first optical splitter is configured to transmit the first set of optical pulses to each subsystem in the first plurality of subsystems. Each subsystem in the first plurality of subsystems is configured to modulate the first set of optical pulses based on the generated digital values and thereby generate a modulated optical pulse stream.

Abstract: An optical transmission controller for controlling an optical transmission system is presented. The optical transmission controller according to the present invention includes a laser controller, a modulator block controller, and a modulation driver controller. In some embodiments, the optical transmission controller is formed on a single integrated circuit chip. In some embodiments, the optical transmission controller includes a digital signal processor or microprocessor executing instructions for providing signals to a laser module, a modulator block and modulation drivers.

Abstract: Methods and apparatus are described for processing an optical signal. The optical signal comprises at least a first channel signal at a first wavelength modulated by a first frequency, a second channel signal at a second wavelength modulated by a second frequency, and a third channel signal at a third wavelength modulated by a third frequency. The method includes receiving the optical signal, and splitting the received optical signal into at least two optical bands, a first optical band comprising the first and second channel signals, and a second optical band comprising the third channel signal. A first electrical signal is formed, proportional to the total optical power of the first optical band.

Abstract: An image forming device includes a developer container sectioned into a plurality of chambers, an image forming unit which forms an image by using a developer supplied from the developer container, sensors which are respectively provided in at least two of the chambers of the developer container and detect the remaining amount of the developer in the chambers, and a determining unit which determines a status of the developer in the developer container in accordance with the remaining amount of the developer detected by the sensors.

Abstract: The present invention provides a detector that brings a cleaning blade made from elastomer in contact with a photoconductor to observe vibrations of the cleaning blade or a supporting member for the cleaning blade and calculates an index value based upon a normal condition using multi-dimensional data for each frequency obtained by Fourier transform of the vibrations as signals, thereby detecting abnormality of a condition of contact of the cleaning blade with the photoconductor such as the presence of adhesion material or damage to the photoconductor.

Abstract: In an image forming apparatus which has a medium thickness detecting unit for detecting a thickness of print medium and forms an image by an electrophotographic process, the apparatus has a unit for detecting the thickness of print medium that is used after a predetermined operation and a unit for detecting the thicknesses of print media on a paper feed tray at a period of a predetermined number of print pages. A target temperature of a fixing device is set on the basis of the thickness of print medium that is used after the predetermined operation and the thicknesses of print media detected at the period of the predetermined number of print pages. A waiting time is reduced and print quality can be maintained by this apparatus.

Abstract: A charging device including: a first charger which charges a member to be charged, the first charger having conducting particles which come into contact with the member to be charged; a second charger which charges the member to be charged in a same polarity as charging polarity of the first charger on an upstream side of the first charger in a moving direction of the member to be charged; and a controller which controls application of a charging voltage to the first charger, in which the controller turns a charging voltage on or off in an area of the member to be charged which is not subjected to charging by the second charger.