Abstract: Light pulses can be stopped and stored coherently, with an all-optical process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. This is accomplished only by small refractive index modulations performed at moderate speeds and has applications ranging from quantum communications and computing to coherent all-optical memory devices. A complete time reversal and/or temporal/spectral compression and expansion operation on any electromagnetic field is accomplished using only small refractive index modulations and linear optical elements.

Abstract: The present invention is a dispersion compensation device capable of varying dispersion compensation amount with a simple configuration. The device includes a first mode light conversion section capable of converting input light into light of higher mode, a dispersion compensation section capable of performing dispersion compensation on the higher mode light outputted from the first mode light conversion section corresponding to the status of mode of the higher mode light, a second mode light conversion section capable of converting the light of higher mode dispersion-compensated in the dispersion compensation section into light of original mode, and a mode control section capable of variably controlling the status of mode of the higher mode light converted in the first mode light conversion section, and controlling to convert the higher mode light from the dispersion compensation section to the light of original mode in the second mode light conversion section.

Abstract: Provided is an apparatus for writing Bragg gratings and a reflection unit used in the same capable of readily adjusting an incident angle of light radiated from a light source, in order to write Bragg gratings on a target object such as an optical fiber. In accordance with the present invention, it is possible to readily adjust the incident angle of light introduced into the target object using the reflection unit when the position of the target object changes or an interval between the Bragg gratings is adjusted.

Abstract: The present invention provides a new and unique method for increasing the photosensitivity of a large diameter optical waveguide having a cross-section of at least about 0.3 millimeters. The method features loading the large diameter optical waveguide with a photosensitizing gas at a pressure at least about 4000 pounds per square inch (PSI) at a temperature of at least about 250° Celsius. The photosensitizing gas may be hydrogen, Deuterium or other suitable gas. The method also includes the step of using a particular large diameter optical waveguide having a core more than 1000 microns from the surface thereof. The method may be used as part of a process for writing a Bragg grating in an inner core or a cladding of the large diameter optical waveguide.

Abstract: An optical apparatus comprises a substrate, first and second transmission optical elements on the substrate, and an optical component (such as an isolator) and focusing optical element(s) on the substrate between the transmission elements. Transmission elements may include planar waveguide(s) formed on the substrate and/or optical fiber(s) mounted in groove(s) on the substrate. The focusing element(s) may include: gradient-index (GRIN) segment(s) mounted on the substrate or spliced onto a fiber, a focusing segment(s) of a planar waveguide, ball lens(es), aspheric lens(es), and/or Fresnel lens(es). A dual-lens optical assembly comprises a pair of GRIN segments secured to a substrate in one or more grooves, and may be formed from a common length of GRIN optical medium. An optical component (such as an isolator) is positioned between the paired GRIN segments, and optical power is transmitted by the dual-lens assembly between planar waveguide(s) and/or fiber(s) through the optical component.

Abstract: Herein described is a method and system for identifying buffer tubes in a cable by including at least one colored filling material within a transparent or translucent buffer tube.

Abstract: A fiber optic cable assembly with an optical fiber extending through first and second overlapping cable jackets. The first cable jacket is slidably received within a longitudinal opening of the second cable jacket. A first end of the optical fiber is fixed with respect to the first cable jacket and a second optical fiber is fixed with respect to the second cable jacket. The two cable jackets overlap and are slidably movable with respect to each other. A method forming a cable assembly.

Abstract: A fiber optic cable includes a miniature bend at one end, connecting a pair of optical fibers forming an originating light path with a return light path. The use of the miniature bend to connect to the originating and return light paths results in an end portion of the cable having a sufficiently small diameter to permit the cable to be blown into otherwise inaccessible locations, for example, the control line of an oil well.

Abstract: A system for configuring fiber optic communication channels between arrays of emitters and detectors comprises: an array of light emitters; an array of light detectors; a bundle of optical fibers disposed between the arrays of light emitters and light detectors for conducting light from the light emitters to the light detectors, wherein a diameter of each optical fiber in the bundle is greater than a diameter of light emitted from each light emitter in the array, and wherein an area cross-section of the bundle of optical fibers overlaps the array of light emitters and the array of light detectors; and logic for mapping at least one emitter to at least one detector to establish at least one fiber optic communication channel between the array of light emitters and the array of light detectors. A counterpart method is also disclosed.

Abstract: An optical filter includes a body of a polyhedron structure in which a recess having a predetermined depth from one side surface is exposed on a front surface and a rear surface and a multi-layer thin film which is deposited on the front surface of the body to cover an exposed portion of the recess of the body.

Abstract: A 3D Photonic Bandgap Device in SOI (NC#98374). The structure includes a substrate having a semiconductor layer over an insulator layer and a 3D photonic bandgap structure having at least one period operatively coupled to the substrate. The apparatus has a funnel waveguide configuration.

Abstract: The methods and apparatus of the present invention provide advantages for remote laser delivery systems that conduct high levels of light energy through a fiber optic cable to a selectable target surface. Helical fiber optic mode scramblers in accordance with the present invention are an integral portion of a fiber optic cable having a rigid curvature predetermined to advantageously influence the intermodal dispersion characteristics of the fiber optic cable. The various aspects of the present inventions may be employed to increase the useful life of a fiber optic cable, increase the energy throughput of a fiber optics cable, implement smaller sized scramblers, implement more efficient scramblers or to provide for robust implementations that are also easy to assemble. Scrambler assemblies in accordance with the present invention include a support structure and a cylindrical sleeve that work in tandem to maintain to the predetermined spiral curvature of the helical mode scrambler.

Abstract: The present innovation discloses the design, configuration and process of a kind of MEMS-based tunable optical devices. The devices can be classed as dual-cavity of Fabry-Perot resonators, which consist of a first outer membrane, a middle membrane and a second outer membrane. And these membranes are separated by cavities. The membranes will deflect under electrostatic force and the thicknesses of cavities will change. The numbers of the layers of membranes should satisfy an equation. These devices can be adopted for optical switches, VOA or tunable filters.

Abstract: The present I/O ports comprise (1) a layered structure comprising (a) an unpatterned superstrate having at least one layer, (b) an unpatterned substrate having at least one layer, and (c) at least one intermediate layer sandwiched between the unpatterned superstrate and the unpatterned substrate, (2) a coupling region that is within the at least one intermediate layer and that comprises an arrangement of at least one optical scattering element and (3) at least one output waveguide. The present I/O ports can be effectively used in balanced photonic circuits and unbalanced photonic circuits.

Abstract: A brightness enhancement film includes a light-refracting microstructure layer, a substrate and a reinforcing layer. The substrate has a first surface and a second surface opposite thereto. The light-refracting microstructure layer is arranged on the first surface of the substrate and is so configured to vary in curvatures for refracting light. The reinforcing layer is arranged on the second surface of the substrate and is so configured to form a relatively high degree of hardness. Accordingly, the reinforcing layer can prevent warpage and abrasion of the brightness enhancement film.

Abstract: A brightness enhancement film having a light-guiding structure includes a substrate, which has a light-guiding layer and a plurality of light-refracting microstructures. The substrate has a light incident surface and a light emission surface opposite thereto. The light-refracting microstructures are arranged on the light incident surface of the substrate and are provided for varying surface curvatures to refract incident light. The light-guiding layer is arranged on the light emission surface of the substrate and is provided for guiding refracted light to generate homogeneous light to emit therefrom.

Abstract: An optical waveguide plate for a surface light emitting apparatus and a surface light emitting apparatus using the optical waveguide plate that provides excellent uniformity in surface emission is disclosed. The optical waveguide plate comprises an end face introducing light emitted from a light source, and a light emitting surface outputting light introduced from the end face. The end face has a light introducing portion comprising a plurality of notched prisms which disperse incident light. The intervals between two adjacent prisms are set to become greater in proportion to the distance from the center of the light introducing portion. The angles of the prisms are also adjusted to provide uniform surface emission.

Abstract: The method and apparatus operates in a video recorder and playback unit to identify selected broadcast segments, such as commercial advertisements, of a television signal in real-time for the purpose of either suspending recording or advancing playback of the television signal during each unwanted segment. A signature pattern associated with each segment of the television signal is detected and compared to stored signature patterns representative of selected segments such as commercial advertisement segments. If the signature pattern matches one of the stored signature patterns, the segment is thereby immediately identified as being one of the selected segments and is processed in real-time to control operation of the video recorder/player. If the signature pattern of the segment does not match any of the stored signature patterns, the segment is analyzed to determine whether the segment is nevertheless a selected segment and, if so, its signature pattern is stored along with the stored signature patterns.

Abstract: An apparatus for displaying video output with dynamically adjustable drop rate to control playback quality. The inventive apparatus includes a playback engine, a pre-fetch engine, a rendering engine, and a drawing engine. The playback engine sends a pre-fetch requirement and a playback requirement. The pre-fetch engine receives the pre-fetch requirement, obtains frame data according to the pre-fetch requirement, and stores it in a pre-fetch buffer. The pre-fetch engine also adjusts the drop rate of related conditions of the frame data. The rendering engine obtains frame data, decodes, and filters the frame data. The drawing engine outputs the frame data.

Abstract: An information regenerating unit has a semiconductor memory (2) containing predetermined compressed animation file data that have been electrically stored and mounted detachably to a main body; an MPEG decoder (7) for reading the compressed animation file data to apply uncompressing processes thereto, and mounted to the main body; an NTSC encoder (8) for converting the uncompressed regenerated image data to image data in accordance with a predetermined outputting system, and mounted to the main body; an LCD (3) for displaying the image data on a predetermined displaying region, and mounted to the main body or the outside thereof; and a microcomputer (6) for regenerating repeatedly the image data in each predetermined unit on the basis of the compressed animation file data, whereby the unit is downsized and reliability of data regenerated is improved.

Abstract: A recording arrangement (1) for receiving and recording a television signal (F) and for receiving an information signal (I) which contains television program information (FPI), for example, title information about future television programs. The recording arrangement (1) has a keyword detector (54) which derives at least one keyword characteristic of the fields of interest of the user from title information of a television program recorded by the recording arrangement (1). A selector (58) selects, from the title information of future television programs, which is contained in the television program information (FPI), the title information containing at least one detected keyword. Selected television programs can be displayed on a display device (3) or can be recorded automatically.

Abstract: The invention concerns a method (200) and system (100) for recording multiple programs onto a storage medium. The invention includes the steps of: receiving (210) a plurality of multimedia inputs; sampling (212) the multimedia inputs such that the sampled multimedia inputs contain a portion of the plurality of multimedia inputs; combining (214) the sampled multimedia inputs; and encoding (216) the sampled multimedia inputs such that the number of encoding devices required to encode the sampled multimedia inputs is less than the number of the plurality of multimedia inputs. The invention can also include the step of playing back (220) the sampled multimedia inputs. In one arrangement, the playing back step can further include the steps of: decoding (226) at least one of the encoded sampled multimedia inputs to provide a decoded signal; and processing (228) the decoded signal to enable the display of at least one of the multimedia inputs.

Abstract: An image signal processing apparatus includes a hard disk. The hard disk is as necessary created with a directory to which time information according to a time counter is assigned. An image file is stored in a latest directory having the latest creation time among a plurality of directories thus created. When a time indicated by the time counter is modified retroactive to the past, a marker is added to a directory having the time information according to the time counter before being modified. The latest directory is detected on the basis of the marker and the time information.

Abstract: The erasion level appending range of a file is instructed. According to this instruction, the erasion level is set. When this setting range does not agree with the cell unit of the current cell, the current cell is divided to set a sequence of divided cells. Playback management information of each of the divided cells and current cell is re-created, and erasion level information is appended to playback management information of the divided cell that belongs to the appending range.

Abstract: When moving pictures are recorded onto an optical disc, not only is text data recorded, but also video-recording start date and time, video-recording end date and time, and source name or channel number serving as primary text data are recorded in alphanumeric characters program by program or cell by cell, a program or a cell being used as a unit of video-recording. Other text data is recorded together with language code. Since the primary text data used to select video data is expressed in alphanumeric characters, a program or cell to be reproduced can be selected, regardless of language, and the text information in the same language as that of the apparatus can be searched for.

Abstract: Content of multiple digital bit streams with essentially the same renderable content, and situated at mutually remote locations, are played back in unison. First, time is synchronized among the processors that participate in a synchronized viewing session by playing back respective streams. Second, the playbacks are content-wise aligned, by rewinding or fast forwarding, to effect overall a precisely synchronized presentation. The content-wise alignment is achieved by means of a status message between processors that contains information characteristic of the sender's bit stream. If any participant, performs a control function (e.g. rewind, fast forward, stop), all other participants follow synchronously. The processor that initiates the session is deemed the initiator, a role that is thereafter assumed by the participant that has last performed a control function.

Abstract: A digital video data recording system has a signal source, a motion detector, an external memory for storing motion vector data, an encoder, a recorder, and a controller. The controller obtains motion vector data and quantization step size data in a preprocessing procedure, and encodes image data using the motion vector data read from the external memory and the quantization step size data and records the encoded image information on a recording medium in a recording process. The digital video data recording system can encode image information appropriately depending on the type of the image information, minimizes the consumption of electric energy by not effecting a motion detecting process in the recording process, and can record all the image information to be recorded on the recording medium.

Abstract: An MPEG data recorder comprises an interface means for receiving a data packet from a digital transmission line transmitting MPEG data in real time, and extracting a predetermined MPEG data from a received packet to output it as a data signal; a data rate detector means for determining a data rate of MPEG data based on a valid data period, during which the data signal is outputted from the interface means; and a recording mode selector means for selecting a recording mode based on the determined data rate. According to such a configuration, the data rate of MPEG data can be detected without a necessity of analyzing the MPEG data, which would require an MPEG system layer decoder, and thereby an MPEG data recorder can be obtained, in which MPEG data are recorded efficiently in a proper recording mode, with a simplified circuit configuration.

Abstract: Provided is a digital video recorder for processing digital video data continuously input in frame units and storing the data on a video storing portion, which includes a wavelet conversion portion to classify digital video data of a present frame by frequency band, a motion area dividing portion to divide the present frame into a high frequency band and a low frequency band according to the digital video data classified by the wavelet conversion portion, a motion detecting portion to generate fractal coefficients from video data in the low frequency band of the present frame, compare the generated fractal coefficients with fractal coefficients of a preceding frame to obtain difference values therebetween, and obtain motion information of the present frame from the difference values, and an adaptive storage control portion to obtain a motion weighted value of the present frame according to the motion information from the motion detecting portion when a storage capacity of the video storing portion is not more

Abstract: The image signal reproduction apparatus for reproducing a main image signal including either a first type of image signal obtained by converting a film material image into an electrical signal or a second type of image signal including a video signal as a material thereof, using a transfer information including the main image signal and a determination flag for determining whether the main image signal is the first type of image signal or the second type of image signal.

Abstract: An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly linear lamps for emitting light energy onto a wafer. The linear lamps can be placed in various configurations. In accordance with the present invention, tuning devices which are used to adjust the overall irradiance distribution of the light energy sources are included in the heating device. The tuning devices can be, for instance, are lamps or lasers.

Abstract: An optical apparatus has an imaging optical system provided with a deformable mirror and an electronic zoom function that an image recorded in an image sensor by the imaging optical system is magnified by image processing. A ray deflecting function of the deformable mirror is changed in accordance with a change of an object area corresponding to an image to be used, and aberration of the imaging optical system is optimized. The deformable mirror is controlled by an arithmetical unit connected to an image processor and a driving circuit. The electronic zoom is performed with respect to the image recorded in the image sensor through a signal processing circuit and the image processor, and when the image is displayed on a display device, the deformable mirror is deformed so that sharpness at nearly the center of an object image formed on the image sensor is improved.

Abstract: In a photographic processing method, an image unit having a plurality of printable image frames is received. The image frames include a data frame having subchannel information. An indicator of the presence of the subchannel information is detected. A bitstream of all of the image frames is generated. Responsive to the indicator, the data frame is extracted from the bitstream and subchannel information is read from the data frame. Fulfillment of image frames of the bitstream is provided in accordance with the subchannel information. If no indicator is detected, then the image frames are fulfilled in accordance with a different, default subchannel.

Abstract: A method for performing protection switching in an optical network does so in an optimal manner by performing the protection switching actions in the various nodes of a protection path in parallel rather than in sequence. To do so, a channel failure message is transmitted from an end node A in the optical network upon detecting a failure in a link in the optical network that includes the end node A. If a failure can be detected at both end nodes, the channel failure messages are transmitted from both end nodes the moment they detect failure without any further waiting. Upon receiving the first channel failure message regardless its originating end node, switching actions in intermediate nodes are initiated. The channel failure messages are forwarded from the intermediate nodes to their corresponding next nodes before completing switching actions in the intermediate nodes.

Abstract: A method of controlling an optical signal receiver utilizes three control loops: a first control loop tunes the decision threshold of the receiver when the optical network is in a substantially steady state and a second control loop rapidly switches to a reference decision threshold upon the occurrence of an alarm condition. The invention rapidly switches to a predetermined reference decision threshold to compensate for optical signal changes in eye Q and received power after a protection switch or traffic reroute. After a protection switch, a slower tuning algorithm is used to adjust the decision threshold to a more optimum value. In the third control loop, the optical signal receiver may utilize a peak detector that detects the optical signal peak and a potentiometer that is commanded by a controller to output a commanded percentage of this peak value to adjust the threshold and thereby respond to transients.

Abstract: A router comprising an interface module (IM), having an optical path and an electrical path and a speed sensor coupled between an input of the router and an input of the IM. The speed sensor is adapted to receive a packet and detect a speed of the IM connection and in response to the speed of the IM connection being above a threshold value, the speed sensor provides the packet to the optical path of the IM and in response to the relative speed being below the threshold value, the speed sensor provides the packet to the electrical path of the IM.

Abstract: Two signal lights having different wavelengths are bidirectionally transmitted on an optical-fiber transmission-line. A Raman pump light source generates a first Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the first signal light and without response to the second signal light. Another Raman pump light source generates a second Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the second signal light and without response to the first signal light. The first Raman pump light and the second Raman pump light are differently injected from respective input/output terminals into the optical-fiber transmission-line by optical combining and branching filters.

Abstract: An optical fiber network can include an outdoor laser transceiver node that can be positioned in close proximity to the subscribers of an optical fiber network. The outdoor laser transceiver node does not require active cooling and heating devices that control the temperature surrounding the laser transceiver node. The laser transceiver node can adjust a subscriber's bandwidth on a subscription basis or on an as-needed basis. The laser transceiver node can also offer data bandwidth to the subscriber in preassigned increments. Additionally, the laser transceiver node lends itself to efficient upgrading that can be performed entirely on the network side. The laser transceiver node can also provide high speed symmetrical data transmission. Further, the laser transceiver node can utilize off-the-shelf hardware to generate optical signals such as Fabry-Perot (F-P) laser transmitters, distributed feed back lasers (DFB), or vertical cavity surface emitting lasers (VCSELs).

Abstract: A wavelength division multiplexing optical transmission system, an optical loading-channel transmitters, a WDM optical transmitter and a method of optically loading an optical transmission line with multiple optical loading channels. The multiple optical loading channels are produced in the form of an optical comb by using a periodic optical filtering apparatus incorporated within a resonator constructed as an optical loop. A plurality of optical loading channels of the generated optical comb are then output without data being modulated thereon.

Abstract: A WDM (Wavelength Division Multiplexing) light source apparatus using a SOA (Semiconductor Optical Amplifier) is disclosed. The WDM light source apparatus includes N SOAs, a 1×N multiplexer/demultiplexer, and a reflective mirror. The N SOAs have one end coated with a substance of a first reflection factor and the other end coated with a substance of a second reflection factor, directly modulate their input signals into optical signals according to a high-speed data signal to be transmitted, and amplify the modulated signal. The 1×N multiplexer/demultiplexer has one end composed of N terminals and the other end composed of one terminal. The N terminals are coupled with the N SOAs. The reflective mirror having a high reflection factor is connected to one terminal of the 1×N multiplexer/demultiplexer to reflect a signal received from the 1×N multiplexer/demultiplexer.

Abstract: A branching unit for an optical transmission system, an optical transmission system and a method of operation of said branching unit (30) is disclosed having a first branch (38) and a second branch (40), each connected to a main branch (42). First directional current flow means (54) and second directional current flow means (58) are operable to allow electrical current to flow substantially in one direction only along the first branch (38) and the second branch (40) respectively such that electrical current flow from the first branch to the second branch and from the second branch to the first branch is substantially prevented and a simultaneous conduction of current between the first branch and the main branch and between the second branch and the main branch is prevented.

Abstract: An optoelectronic RF signal receiver utilizes a first RF to photonic modulator for receiving an optical carrier signal and an electrical signal from a local oscillator and producing an optical carrier signal with first optical sidebands offset from the carrier signal by the local oscillator frequency. A second RF to photonic modulator receives an electrical RF signal and the signals from the first modulator and produces second sidebands to each of the first optical sidebands from the first modulator with each of the second sidebands being offset from the first sidebands by the RF signal frequency. A detector then receives signals produced by the second modulator and produces an electrical IF signal for further processing. The receiver does not utilize a frequency translation device in the RF signal path and thereby eliminates RF loss, noise, and limited dynamic range characteristic of prior art electro-optical receivers.

Abstract: An optical space communications device includes a transmitter circuit which assigns an idle code indicating that the device is transmitting no data so that the idle code differs from an idle code for another device and which, when the transmitter circuit continuously transmits such idle codes, inserts, between the idle codes, a random code having a different random pattern from a pattern of the idle codes. Thus, light from another device is distinguished from stray light based on the idle codes. A disconnection of the other device is reliably detected. The insertion of random codes reduces effect of crosstalk jitter.

Abstract: An add-side laser in an optical device, such as an add/drop multiplexer OADM, provides not only a source for an add-side wavelength to be added to an output of the device, but also a reference for a receive-side coherent receiver that is included in the optical device.

Abstract: An integrated post-amplifier and laser driver assembly is provided that includes a digital control interface for communication with an external digital IC controller having an I2C bus configured to receive signal parameter programming input from a user. The PA/LD includes one or more DACs which communicate with the digital control interface by way of a glue logic module. A memory is provided in the PA/LD that communicates with the DACs by way of the glue logic module and stores an algorithm for facilitating implementation of changes to signal parameters of one or more signals by way of the DACs. Signal parameter programming instructions are received at the PA/LD from a user by way of the I2C bus, and/or from the internally coded algorithm, and are used by the DACs to facilitate implementation of changes to signal parameters of one or more signals.

Abstract: An optical transmitter for an optical fiber transmission system is described. The optical transmitter includes an optical source that generates an optical signal having a wavelength at an output. An optical intensity modulator modulates the optical signal with an electrical modulation signal to generate a modulated optical signal at an output. At least one parameter of the optical intensity modulator is chosen to suppress at least one of phase and sideband information in the modulated optical signal. An optical fiber is coupled to the output of the optical intensity modulator. The suppression of the at least one of the phase and the sideband information in the modulated optical signal increases an effective modal bandwidth of the optical fiber.

Abstract: The invention provides a synchronous detector for a unit cell of a read out integrated circuit (ROIC). The synchronous detector includes a bipolar photo-detector formed in a focal plane array (FPA) for sensing light energy. The bipolar photo-detector has one end coupled to a sense node of the unit cell, and another end coupled to a reference generator for biasing the bipolar photo-detector. The bipolar photo-detector is biased by the reference generator, resulting in the light energy sensed by the bipolar photo-detector to be provided to the sense node as a synchronously detected signal. A capacitor is coupled to the sense node for low pass filtering the synchronously detected signal. The reference generator provides alternating positive and negative voltage levels, where the positive voltage level forward biases the bipolar photo-detector and the negative voltage level reverse biases the bipolar photo-detector.

Abstract: A receiver for an optics telecommunication system, the receiver comprises a first receiving device and means for focusing a received light beam carrying a signal towards such first receiving device. The receiver is characterized in that it further comprises at least a second receiving device and a beam splitter for splitting the focused light beam partially towards the first receiving device and partially towards the at least second receiving device. Tipically, the first receiver device is an APD diode while the second receiver device is a PIN diode. The telecommunication system is a Free Space Optics telecommunication system. A method is also described. The invention results in a high dynamic receiver. The dynamic of the invention receiver could be up to the sum of the dynamics of receivers provided with single receiving device (APD or PIN).

Abstract: A system and method are provided for notifying a user of a document left at a xerographic apparatus, such as a printer or copier. The system includes a sensor module for sensing the document and determining whether the user is within a predetermined distance of the xerographic apparatus. The system further includes a notification module for notifying the user of the document left if the copier user is outside the predetermined distance of the copier. The system and method can utilize RFID transponders each worn by a respective copier user or input data for determining the identity of the user. Notification can be accomplished by one of several methods, such as transmitting an electronic message to the user, actuating an alarm located near or at the xerographic apparatus, and preventing further use of the apparatus until the document is retrieved.

Abstract: When the remaining toner amount within a developer is relatively large, a control target value of a toner amount is set to Ttgt1, and a lower limit value of a toner amount which can regarded proper is set to TL1. When the density of a patch image formed under a predetermined condition is smaller than a minimum guaranteed density Dma, it is determined abnormality has occurred in the apparatus. Since the characteristic of toner within the developer changes as the remaining toner amount decreases, the control target value is changed to Ttgt2 and the lower limit value is set to TL2 in light of this. In this fashion, regardless of whether the toner characteristic has changed, abnormality in the apparatus is detected without fail.