Abstract: The contents of sealed envelopes are accessed using radiation to differentially heat information patterns within the contents and conduction to transfer corresponding thermal patterns to the envelopes' outer surfaces. The radiation is preferably within the wavelengths of microwaves or radio waves for penetrating the envelopes. The information pattern differentially absorbs the radiation by converting the attendant radiant energy into heat by either induction heating or dielectric heating. An infrared camera or other thermally sensitive device converts the thermal patterns conducted to the envelopes' outer surfaces into corresponding electrical patterns for further processing.

Abstract: A position sensor for providing an electronic output indicating the magnitude of transverse movement of an edge of a magnetic tape. A first light pipe and lens arrangement is used to deliver light to one side of a tape. A second light pipe with a small light receiving aperture is used to receive light and to deliver the received light to a detector. The focal point for the lens in the first light pipe is at the receiving aperture of the second light pipe, enabling the aperture to be very small but still receive substantially all the transmitted light. The light pipe arrangement enables use of a variety of light sources and light detectors without having to place either a source or a detector physically close to the tape or the magnetic head.

Abstract: This invention pertains to a detection system for locating and counting identification marks attached to a written or printed item. A signal processing method and apparatus is described which allows detection of multiple character marks as a single event in continually moving linear materials. The marks are passed between the path of a detection zone comprising a light source and a photodetector to precipitate a voltage drop and feeding that drop to a circuit that recognizes the drop and simultaneously triggers a time window during which changes in voltage are ignored, which time window is no longer than the time it takes for a full mark to pass under the zone and shorter than the time it takes for the leading edge of the next multicharacter marks to reach the detection zone.

Abstract: A method and device for acquiring data related to topography of a medium includes projecting light, allowably from more than one direction, onto the surface of the medium at an angle of less than sixteen degrees relative to the surface and imaging the surface. For example, the imaging sensor may be an array of sensor elements that is used to determine navigation of a hand-held scanner along an original. By introducing light at an angle of less than sixteen degrees, surface irregularities cast shadows that form a high contrast illumination pattern along the surface of the medium. The navigation sensor detects multi-element variations of intensity of scattered light from the surface with respect to positions along the surface, so that the Nyquist criteria are adequately satisfied. Typically, the light is collimated incoherent light, but this is not critical. The illumination angle can be established by using a prism. The prism may have an antireflective thin film coating on one or more prism faces.

Abstract: A scanning device and method for forming a scanned electronic image include using navigation information that is acquired along with image data, and then rectifying the image data based upon the navigation and image information. The navigation information is obtained in frames. The differences between consecutive frames are detected and accumulated, and this accumulated displacement value is representative of a position of the scanning device relative to a reference. The image data is then positioned-tagged using the position data obtained from the accumulated displacement value. To avoid the accumulation of errors, the accumulated displacement value obtained from consecutive frames is updated by comparing a current frame with a much earlier frame stored in memory and using the resulting difference as the displacement from the earlier frame. These larger displacement steps are then accumulated to determine the relative position of the scanning device.

Abstract: A web error recovery divert system is provided. A web is printed and scanned for errors. An error is identified in a grouping of sections or pages. A replacement grouping of sections or pages is printed. The replacement grouping includes an identifying mark or banner page indicating the presence of a replacement section. The web is redirected through a cutter and diverter that identifies the banner page and, at the appropriate locations, cuts and removes the grouping having the error. The replacement grouping and the remainder of the web is driven to a post-processing unit for further operations.

Abstract: A position detecting apparatus comprises a double-beam producing device for producing two beams different in frequency from each other, which are guided to irradiate a diffraction grating on an object to be inspected in two predetermined directions, and a detector photoelectrically detecting through an objective optical system diffracted light produced by the diffraction grating, in which the double-beam producing device comprises a light source for supplying a beam of a single wavelength or multiple wavelengths, a beam splitting device for splitting the beam from the light source into two predetermined beams, a relay optical system for converging the two split beams at a predetermined position, and a frequency difference producing device disposed at or near a converging position by the relay optical system, for producing a predetermined frequency difference between the two split beams.

Abstract: A position detecting apparatus comprises a double-beam producing device for producing two beams different in frequency from each other, which are guided to irradiate a diffraction grating on an object to be inspected in two predetermined directions, and a detector photoelectrically detecting through an objective optical system diffracted light produced by the diffraction grating, in which the double-beam producing device comprises a light source for supplying a beam of a single wavelength or multiple wavelengths, a beam splitting device for splitting the beam from the light source into two predetermined beams, a relay optical system for converging the two split beams at a predetermined position, and a frequency difference producing device disposed at or near a converging position by the relay optical system, for producing a predetermined frequency difference between the two split beams.

Abstract: A position detecting apparatus comprises a double-beam producing device for producing two beams different in frequency from each other, which are guided to irradiate a diffraction grating on an object to be inspected in two predetermined directions, and a detector photoelectrically detecting through an objective optical system diffracted light produced by the diffraction grating, in which the double-beam producing device comprises a light source for supplying a beam of a single wavelength or multiple wavelengths, a beam splitting device for splitting the beam from the light source into two predetermined beams, a relay optical system for converging the two split beams at a predetermined position, and a frequency difference producing device disposed at or near a converging position by the relay optical system, for producing a predetermined frequency difference between the two split beams.

Abstract: A plane positioning apparatus comprises a projector for projecting beams to a given portion on the surface of a substrate in a diagonal direction, a light receiving device to receive beams reflected from the substrate surface and output photoelectric signals in accordance with variation of the light receiving position, a calculating circuit to output deviation signals in accordance with the deviation amount of the substrate surface with respect to a predetermined fiducial plane based on the deviation signals, a substrate shifting device to shift and set the substrate at a given position in a direction perpendicular to the fiducial plane in accordance with the deviation signals, a level variation detecting device to detect level variation of the deviation signals generated when the substrate surface and the fiducial plane are displaced interrelatedly, an inclination calculating device to calculate, in accordance with the level variation characteristics, the value of the inclination of the level variation chara

Abstract: A position detecting apparatus comprises a double-beam producing device for producing two beams different in frequency from each other, which are guided to irradiate a diffraction grating on an object to be inspected in two predetermined directions, and a detector photoelectrically detecting through an objective optical system diffracted light produced by the diffraction grating, in which the double-beam producing device comprises a light source for supplying a beam of a single wavelength or multiple wavelengths, a beam splitting device for splitting the beam from the light source into two predetermined beams, a relay optical system for converging the two split beams at a predetermined position, and a frequency difference producing device disposed at or near a converging position by the relay optical system, for producing a predetermined frequency difference between the two split beams.

Abstract: The invention described herein is an alignment system used in semiconductor manufacturing. It is the core component used to align a mask containing a circuit pattern to a wafer during a scanning sequence. The alignment system images an alignment reticle pattern onto a wafer which contains alignment marks. During scanning, the light from the alignment reticle image is reflected and scattered by the wafer and its alignment marks. Multiple detectors are placed at a pupil plane of the alignment system to collect the reflected and scattered light in the bright-field and dark-field regions. The resulting signals and their analysis results in determination of accurate alignment of a wafer. The alignment system does not use or "look through" the projection optics of the scanning photolithographic device. The broadband spectrum used for alignment illumination cannot be used in the projection optics designed for the deep UV wavelengths without undesirable results.

Abstract: A paper attribute detector for use in combination with a strip chart recorder includes a paper web having a plurality of connected pages. Each of the pages has electronically scannable indicia preferably on an unrecorded side of the paper. In the preferred embodiment, the indicia are realized in bar code form and are used to encode various attributes such as page number, paper quality, paper sensitivity, and so on. Indicia scanning means are provided for detecting the page indicia as the paper web travels through the recorder. In the preferred embodiment, the scanning means includes one or more electro-optical sensors. The indicia may be aligned parallel to or transverse the travel direction of the web.

Abstract: To reach an originally set web position again with a web movement control device following a tear in the web and renewed drawing-in of a web of material, sensors which can be adjusted independently of one another and coupled such that two sensors move synchronously in opposite directions are provided. During an edge search, the two sensors can be adjusted separately and independently of one another and moved synchronously in opposite directions for centre control after a tear in the web for repositioning the sensors.

Abstract: Apparatus, and a corresponding method for its use, for producing an enhanced image of a reflective target on a remote object, such as a space vehicle with which docking maneuvers are being carried out. Radiation at two separate wavelengths illuminates the target, and reflected radiation is separated by wavelength to produce two images simultaneously. Because the target is responsive to only one of the wavelengths, but reflections from other objects are received for both wavelengths, subtraction of the two images substantially removes unwanted image components resulting from reflections from objects other than the target. Producing the two images simultaneously, using two cameras, ensures that the unwanted image components are substantially the same in the two images, and can therefore be removed by subtraction during image processing.

Abstract: A novel exposure system includes a reduced-projection lens optimized for a predetermined single exposure wavelength and a chromatic aberration correction system for TTL (Through The Lens) alignment with broadband light. The correction system includes a holographic lens which dispersion has a negative number in contrast to a conventional glass lens which has a positive dispersion number. By employing a holographic lens, the total optical length of an alignment system can be made short enough to avoid the necessity of installing a mirror therein, thus realizing a highly accurate alignment system.

Abstract: In a web movement control device with a sensor which detects the edge of a moving web of material in a contact-free manner and can be adjusted by a sensor adjustment device, to compensate for a change of material to be controlled and/or a soiling of sensors, the sensor adjustment device is driven by an electronic signal processing device to adjust movement transversely with respect to the edge of the web. The signal processing device monitors the sensor signal changes which occur and derives a bright value or a dark value from the absence of a signal change during the movement adjustment stores the value. An intermediate value is calculated from the stored value as a control value for web movement control and stored. Under given operating conditions, this program cycle is repeated.

Abstract: In detecting indices (references) provided on a base paper with a distance therebetween along the longitudinal direction of the base paper, wherein either passed or reflected light amount through or from the indices differs, by a light detector positioned on a feed path while the indices are fed along the longitudinal direction, a threshold value is renewed each time when at least three indices are detected based upon peak values (maximum and minimum values) of output signals from the light detector. This is accomplished by renewing the threshold value by calculating the new threshold value based upon an intermediate or average value among the peak values between, for example, the indices in order to continue the indices position detecting process in an accurate fashion even if there is an abnormality in the base paper or others when the abnormality is minor such that it does not interfere with the subsequent process.

Abstract: This invention relates to reading and analyzing the contents of sealed mail. The invention has utility in the sorting of sealed mail and in the matching of mail envelopes and its contents. The contents of sealed mail are read by having a light in the near infrared directed to the sealed envelope and creating an image of the printed matter on the contents by directing the light to an optical detector. The image thus received is analyzed and a determination can be made whether contents are of high value or whether the addresses on the envelope match the addresses of the contents. If the envelopes are not addressed, the address can be printed on the envelope after analysis of the address block of the contents.

Abstract: A bar code reader system is adapted to read a micro-bar code and includes a light emitting body for irradiating a light beam onto a bar code surface on which the micro-bar code to be read is provided. A focusing lens focuses a reflected light from the bar code surface. An image pick-up device receives the focused reflected light and forms an image of the micro-bar code to be read. A cylindrical lens body is arranged to pass therethrough both the light beam from the light emitting body and the reflected light beam reflected from the bar code surface. The cylindrical lens body is oriented with an axis thereof substantially consistent with a bar code reading direction.

Abstract: A liquid level monitor for sensing the level of liquid in a tank or vessel, typically an automobile radiator, employing a probe with a light emitting diode and phototransistor mounted inside an enclosure, the enclosure having a transparent lens through which light can pass, and the lens having a prism configuration which diffuses or alters stray light which occurs by reflection off an interior core wall of the vessel and prevents the diffused or dispersed light from rendering the phototransistor conductive and possibly leading to a false indication or reading of liquid level. The light emitting diode is electrically excited with a high-intensity, short duration pulse, which improves the sensitivity of the monitor.

Abstract: A method and apparatus for predicting the position of a register mark within an image on an elongate web relative to a reference position of the mark when the image is at a reference position is described. The apparatus includes a detector for obtaining successive samples of the image; a comparator for comparing the samples with a reference threshold so as to generate a binary sequence; and a comparator for comparing the binary sequence with a reference sequence. The apparatus is operable to carry out a series of comparisons between the two sequences with the sequences offset by successive one bit intervals and at each offset position, the number of coincidences between binary values is summed by counters. The resultant sums are then compared and the highest is taken to indicate the degree of offset between the two sequences and is used to predict that the register mark has the same offset.

Abstract: A detecting device for detecting the position of a rotatable image bearing member which is provided in an image forming apparatus. The detecting device has a reference member provided in the image bearing member and a sensor for detecting the reference member. The position of the rotating image bearing member is detected by this detecting device. Further, by this detecting device, the image forming apparatus is able to detect that the image bearing member is slipped in a direction perpendicularly to the image bearing member rotation direction.

Abstract: A method of determining regularity of a pattern array on a substrate to enable sequential positioning of patterns of the array relative to a reference position includes the step of calculating a reliability degree regarding a measured value of a pattern position, and the step of determining the regularity of the pattern array on the basis of the calculated reliability degree, and a design value and the measured value of the pattern position.

Abstract: A process consists of detecting a printed registration mark composed of recognition signals and of a color pilot mark, comparing the image of the signs of the printed registration mark to the signs of a virtual reference registration mark, then defining a basic area for each sign, calculating a geometric center of every basic area, detecting any color pilot mark in these basic areas, calculating and memorizing the geometric center for the detected pilot mark, measuring an offset position between the geometric center of the basic area and the geometric center of the detected color pilot mark and utiliziing the measured offset position for controlling a misregistration correction appliance of a printing press. The device for accomplishing the process includes an arrangement for performing each of the above-mentioned steps.

Abstract: An information retrieval apparatus used in a microfilm reader, a reader/printer, or the like includes a first illuminator for illuminating information and a mark recorded on an information recording medium, a second illuminator for illuminating the mark, and a detector for detecting the mark illuminated by the second illuminator. The second illuminator includes a solid-state light-emitting element for emitting monochromatic radiation having a wavelength of visible light. A designator designates an optimal position of the detector on the basis of a position of the mark projected on a screen is arranged.

Abstract: Apparatus for detecting register marks includes one or more linear arrays of sensors (19, 20) arranged transverse to the direction of relative movement of a web (3) and the apparatus. Where there is more than one linear array (19, 20), they are arranged so that they are substantially non-parallel to allow both longitudinal and transverse monitoring of register marks on the web (3). A signal is generated on detection of a mark and processing means determine the sensor (19) or group of sensors which detected a mark and whether the marks are in register with those of other webs (3).

Abstract: An apparatus for projecting a mask pattern (MA) on a substrate (W) by means of a projection lens system (PL) is described, which apparatus comprises a device for aligning a substrate alignment mark (P.sub.1 ; P.sub.2) with respect to a mask alignment mark (M.sub.1 ; M.sub.2), the projection lens system (PL) forming part of the alignment device. A correction element (25) is arranged in this system (PL) to compensate for the fact that this system (PL) is not optimized for the wavelength of the alignment beam (b).

Abstract: For the control of a cutting to the correct design length, particularly to the correct print image, of continuously conveyed webs of material by means of a cutter unit, the web of material is provided with a bar code which is detected in contactless manner at least for measuring speed and acceleration by means of a sensor. Each bar of the bar code is converted into a signal which may be multiplied in a signal conversion unit. By this means a high degree of precision of the cutting position is obtained.

Abstract: A sheet advancement control system for use in printers such as inkjet printers includes a light source for directing a beam of light onto a localized area of a sheet, a photosensitive detector for providing output signals that vary according to microscopic patterns that are illuminated within the sheet by the directed light, a correlator for determining cross-correlations between pairs of detected patterns as the sheet is advanced in a printer and for computing displacements between matching patterns to, thereby, detect the displacement of a sheet within the printer.

Abstract: A microfilm retrieval system includes blip marks provided at transversely opposite side portions of selected image frames of an elongated microfilm, a device for detecting the blip marks, counters for counting the number of blip marks in accordance with kinds of blip marks, respectively, a device for determining a specific combination of the kinds of blip marks when two or more kinds of blip marks are provided to selected the image frames, and a controller for controlling the counters such that the blip marks are counted with a unit of count and a reset value corresponding to the specific combination of marks determined by the determining device. The unit of count and the reset value at the time of counting blip marks can be set to desired numerical values, and counting is effected by making a page number or the like provided on a photographed object coincide with a count value, thereby facilitating retrieval.

Abstract: Disclosed are "anti-wander" web-transport arrangements wherein web-means are intermittently advanced, while being monitored for misalignment along the transport-path, and also being automatically urged back into proper alignment along this path.

Abstract: A mark sense detector with a threshold detector having a weighted and variable threshold discriminates reflective variations on an illuminated surface such as a hand-marked lottery entry card having a plurality of tracks with potential reflective variations occurring at discrete positions thereon. The card is fed relative to an array of photodetectors for the tracks, each photodetector producing an input signal for a respective one of the tracks in response to reflections of the illuminated surface, the input signal varying with marks and with parameters of the illumination and feeding. The track input signals are applied to follower amplifiers for each of the tracks. An integrator for each of the tracks averages the output of the follower amplifier, the average being divided and applied as the threshold input to a comparator for each of the tracks.

Abstract: A position detection apparatus has a substrate on which a diffraction grating is formed and an alignment optical system for illuminating the diffraction grating with a pair of coherent light beams having different frequencies from each other from different directions. The intensity of interference fringes formed due to the interference of diffracted beams generated in the diffraction grating is detected photo-electrically. The alignment optical system forms the pair of coherent light by using an optical modulator, and two luminous fluxes from the optical modulator pass through independent optical paths positioned symmetrically with the optical axis of the alignment optical system therebetween and reach the diffraction grating from different directions. The alignment optical system has a stop having an opening having an inclined edge with respect to the direction of the grating components of the diffraction grating, the opening being in conjugation with the substrate.

Abstract: Method and an apparatus for determining line centers in a microminiature element such as on a semiconductor wafer or a mask having linewidths and other spacings below the one micron range. The invention uses, two focussed laser beams which are directed across a line on the element, both beams being illuminated successively with a distance therebetween below the classic resolving power. A portion of the incident beam and a portion of the beam reflected from the line is conducted to respective detectors which respectively generate measurement and reference signals. These signals are treated to eliminate high frequency noise components therein. Subsequently, the filtered measurement and reference signals are digitized and synchronously processed to provide two sine shaped curves whose intersection point corresponds to the center of the scanned line.

Abstract: A position signal producing apparatus, for an apparatus for project-printing a pattern on reticle onto a wafer through a project lens with ultraviolet light, for producing a position signal indicative of position of the wafer, comprises: a laser emitting two different frequency components polarized orthogonally with each other which are splitted by a polarizing beam splitter. The first and second components are reflected by first and second mirrors respectively to produce interference fringes at a given place being on an annular region within a circle defined by field angle of the project lens on the reticle through wave plates for circularly-polarizing. Another interference fringes is formed on a diffraction grating of the wafer in correspondence with the interference fringes through the project lens and a lens for achromatizing the project lens at wavelengths of the components. Another interference fringes reflected by the diffraction grating is detected by a photodetector for producing the position signal.

Abstract: An alignment system for aligning a mask and a wafer into a predetermined positional relationship uses alignment marks provided on the mask and the water. In this system, light from a light source is directed to the alignment marks of the mask and the wafer and, then, the light from these alignment marks is detected by an accumulation type photoelectric converting device, for alignment of the mask and the wafer. The accumulation time of the photoelectric converting device is controlled to be sufficiently longer than or to be equal to a multiple, by an integral number, of the period of relative and natural vibration of the mask and the wafer. This makes it possible to reduce the effect of the relative vibration of the mask and the wafer upon the alignment result and, therefore, makes it possible to enhance the alignment precision.

Abstract: A plurality of individual openings provided in a sheet strip material by a stamping device are passed in succession past a monitoring station positioned adjacent the outlet of the stamping device. As each individual opening is passed by the monitoring station, the monitoring station produces a plurality of voltage signals which identify the progress of each opening through the monitoring station and the progress of the sheet strip material through the stamping device. A controller is provided having an input for receiving the plurality of voltage signals produced as each opening passes by the monitoring station and an output connected to the stamping device. Within the controller, the plurality of voltage signals identifying the progress of an individual opening through the monitoring station are compared to the plurality of voltage signals identifying the progress of a following opening through the monitoring station.

Abstract: In an exposing apparatus for copy transferring a pattern formed on a mask onto a substrate, the substrate is supported on a leveling stage mounted on a two-dimensionally movable stage. Two-dimensional deviation amounts of the substrate in relation to the moving stage, caused by inclination of the leveling stage, are detected and are compensated by controlling the movement of the moving stage, thereby correcting the relative positional relation between the mask and the substrate.

Abstract: A system to apply a bar-code label or the like upon a product or to apply a protective laminate strip or the like upon a bar-code label or the like which is already in place upon a product. The label or the protective laminate strip first is removed from a moving carrier and applied to an applicator head which, in turn, applies the label on the product or the protective laminate strip very precisely onto the label. The relative positions of the applicator head and the label, for example, are predetermined. It remains to establish the moving forward edge of the bar-code label or the protective laminate strip to be stripped from the moving carrier so that the either can be accurately placed on the applicator head, a particularly vexing problem in view of the fact that transmissivity, usually, or reflectivity of all the films involved, typically, have closely related optical characteristics.

Abstract: A method of and apparatus for detecting a register mark on an elongate web (3) is described. The web (3) carries a number of copies of an image (4) spaced apart along the web (3) and a region of the path along which the web (3) moves is irradiated with infra-red radiation by a source (5). The region is viewed with a series of detectors (1D-1F) as the web (3) passes through the irradiated region and the output levels of the detectors (1D-1F) are monitored for changes in their output levels. An edge extending transverse to the direction of movement (2) of the web (3) is then selected within the image (4) when the monitored changes in the output levels of all the detectors (1D-1F) satisfy predetermined criteria. The edge is then used for subsequent register control.

Abstract: An apparatus for detecting and guiding a web includes a web scanner bar unit that extends across the entire width of the web path for controlling a steering mechanism to maintain a more precise edge and/or center alignment. The web scanner bar unit is formed of an infrared light-emitting diode array and a phototransistor array formed on opposite sides of the web. A microprocessor-based controller unit is provided for controlling the operation of the web scanner bar unit to form right and left eyespots in order to determine the respective right and left edges of the web. Further, the web scanner bar unit is capable of detecting a break in the intermediate area of the web.

Abstract: The invention maintains the focus of a reader in a postal sorting and transporting system which is equipped to read an image of an address on either side of a mail article. The address reading apparatus uses two address readers disposed on opposite sides of a transfer path over which the mail articles travel. An address-carrying surface detector is disposed along the transfer path and upstream of the two address readers. Two floating roller pairs are provided at the inlet and the outlet of the address readers, to hold the mail article therebetween. A pressure roller driving mechanism responds to an output signal delivered from the address-carrying surface detector for selectively fixing one roller of either roller pair at a predetermined distance from the mail article's address carrying surface so that the distance between the address carrying surface and the appropriate address reader is kept constant.

Abstract: A plurality of individual openings provided in a sheet strip material by a stamping device are passed in succession through a monitoring station positioned adjacent the outlet of the stamping device. As each individual opening is passed through the monitoring station, the monitoring station produces a plurality of voltage signals which identify the progres of each opening through the monitoring station and the progres of the sheet strip material through the stamping device. A controller is provided having an input for receiving the plurality of voltage signals produced as each opening is passed through the monitoring station and an output connected to the stamping device. Within the controller, the plurality of voltage signals identifying the progress of an individual opening through the monitoring station are compared to the plurality of voltage signals identifying the progress of a following opening through the monitoring station.

Abstract: A method of sequentially positioning different regions of a semiconductor wafer, onto each of which regions an image is to be transferred at a transfer station, the method comprising the steps of: detecting, at a non-transfer station, positions of the different regions of the wafer with respect to a reference mark; detecting, at the transfer station, a position of the reference mark with respect to a standard mark; detecting positions of the different regions of the wafer with respect to the standard mark on the basis of the detection of the position of the reference mark with respect to the standard mark and the detection of the positions of the different regions of the water with respect to the reference mark; and moving the wafer so as to sequentially place the different regions thereof at the transfer station while controlling the movement of the wafer, for the sequential placing, in accordance with the detection of the positions of the different regions of the wafer with respect to the standard mark, whe

Abstract: Semiconductor wafer inspecting apparatus comprises plural supports each adapted to support a wafer to be inspected and a feeder for feeding a wafer to each of the plural supports. The apparatus can effect accurate and rapid positioning of the wafer.

Abstract: A method and apparatus for monitoring the passage of a mark on a web. The web is caused to move through a detection station at which at least that portion of the web carrying the mark is illuminated. An image of the mark is projected onto a quadrant array of photodetector elements at the detection station. The axes defined between the elements are transverse to the direction of movement of the web. The times t.sub.1, t.sub.2 at which substantially equal areas of a mark are projected on either side of the axes are determined which provides an indication of registration of the web.

Abstract: A plurality of individual openings provided in a sheet strip material by a stamping device are passed in succession through a monitoring station positioned adjacent the outlet of the stamping device. As each individual opening is passed through the monitoring station, the monitoring station produces a plurality of voltage signals which identify the progress of each opening through the monitoring station and the progress of the sheet strip material through the stamping device. A controller is provided having an input for receiving the plurality of voltage signals produced as each opening is passed through the monitoring station and an output connected to the stamping device. Within the controller, the plurality of voltage signals identifying the progress of an individual opening through the monitoring station are compared to the plurality of voltage signals identifying the progress of a following opening through the monitoring station.

Abstract: An apparatus for aligning a moving substrate and a read or write head includes independently controllable rollers for deskewing the sensed skew of a moving substrate and a read or write device that is translatable in a direction fixed with respect to the reference direction of the moving substrate.

Abstract: A device for positioning a disk-like workpiece, the device having a system for detecting a change in position of an edge of the workpiece, the detecting system producing a signal; a system for selecting a portion of the signal produced by said detecting means, which portion contains desired positional information, the selecting means producing a signal; and a positioning system for rotating the workpiece on the basis of the signal produced by the selecting system, to thereby position the workpiece.