Abstract: A transportation apparatus includes a first velocity sensor that detects a first measure of the transportation velocity of a medium that is transported, and a second velocity sensor that detects a second measure of the transportation velocity of the medium. The first and second velocity sensors are positioned offset from each other in an intersecting direction that intercepts a transportation direction of the medium. A skew detection section calculates a velocity difference from the first and second measures of the transportation velocities, and determines a skew state of the medium on the basis of the velocity difference.

Abstract: An image forming apparatus includes: a transfer member that is driven to be rotated; an image forming unit configured to form an image on the transfer member; a detection unit configured to detect inclination of the transfer member relative to a rotation direction of the transfer member; and a control unit configured to perform correction control of color misregistration caused by the inclination of the transfer member when an image is formed by the image forming unit, based on the inclination of the transfer member. The control unit is further configured not to perform the correction control when a monochrome image is formed.

Abstract: The invention relates to a device for marking and/or scanning an object comprising a head, in particular a marking head or a scanning head, having a plurality of regular operating elements for marking and/or scanning the object, and comprising a driving mechanism for providing a relative movement of the object relative to the head in an advance direction during a working operation, at least a part of the regular operating elements being arranged in a rectangular pattern of rows and columns.

Abstract: A page-wide array inkjet printer allocates the processing tasks for individual printheads within the array to separate halftoning processors. Each halftoning processor processes the information relating to a strip of the image, with the boundaries between strips running parallel to the print medium advance direction. In a preferred embodiment, the pixels within each strip are processed using a forward error diffusion algorithm operating along columns of pixels parallel to the strip boundaries. The resulting halftone data is supplied from each halftoning processor to one or more uniquely associated printing component controllers, and these controllers generate print instructions for printing components (e.g. inkjet printheads) connected to the printing component controllers via a dedicated communications channel.

Abstract: A method and system for printing documents with one or more embedded security features is provided. Security features are embedded in the document by co-printing magnetic and non-magnetic toner on a receiver before fixation by a fixing station. The combination of magnetic and non-magnetic toners in the image results in image elements that easily show alteration or are undetectable by visual means.

Abstract: An image forming system is provided. The image forming system includes an image forming apparatus configured to form a mark for detecting at least one of a position deviation and a density deviation and obtains a correction amount by detecting the mark, the image forming system comprising: an identification unit configured to identify an image characteristic of an image to be printed according to at least one of a positional relationship between colors, a gradation distribution and a resolution, and a selecting unit configured to select a choice from multiple choices containing at least two choices of: only position deviation; only density deviation; and both position deviation and density deviation, according to the image characteristic identified by the identification unit, wherein the image forming apparatus is configured to form the mark for obtaining the correction amount according to the choice selected by the selecting unit.

Abstract: The present invention relates to a color printer and particularly to a color printer reducing power consumption and complying with international criteria ensuring sustained earth environment. In a color printer having multiple optical writing heads for individual recording colors, the activated periods of individual color recording heads are set to different periods and one writing period of individual recording heads is divided into multiple periods, video data for recording one dot line are divided into multiple blocks in the main scan direction, and the divided video data are used for emission at different times in the sub-scan direction, whereby a smaller number of optical writing elements are simultaneously driven for emission and the peak power consumption of the entire apparatus is reduced.

Abstract: A printing apparatus is provided. The printing apparatus includes an image forming unit to form an image on a sheet in a colorant, a first sheet feeder and a second sheet feeder to supply sheets to the image forming unit, a trial printing system, which conducts a trial printing process to print at least a part of images included in a print job on a sheet supplied from the second sheet feeder when the print job designates the first sheet feeder, a first receiving system, which receives an instruction to continue printing after completion of the trial printing process, and a main printing system, which conducts a main printing process to print the images included in the print job on a sheet supplied from the first sheet feeder when the first receiving system receives the instruction to continue printing.

Abstract: A method of fabricating an inkjet printhead assembly having backside electrical connections. The method comprises the steps of: (a) providing printhead integrated circuits, each having a backside recessed edge portion and connectors extending through the integrated circuit, each connector having a head connected to frontside drive circuitry and a base in the recessed edge portion; (b) positioning a connection end of a connector film in the recessed edge portion; (c) connecting each film contact to the base of a corresponding connector; and (d) attaching the backside of each printhead integrated circuit together with the connector film to an ink supply manifold so as to provide the inkjet printhead assembly having backside electrical connections.

Abstract: In a color reading apparatus for successively reading respective red, green, and blue colors in each line while a document is continuously conveyed to a plurality of line sensor units arranged in a zigzag manner, the line sensor units are arranged with a distance equal to or shorter than a unit of line to prevent a color shift. When read data of the plurality of line sensor units in a conveying direction are to be combined, image data shifted by the number of lines corresponding to distances between the line sensor units in the conveying direction are set as first combination candidates. A color code and a line code are added to each of the data. Image data having the same color code and the same line code are combined. According to the image reading apparatus structured as described above, it is possible to obtain data capable of reproducing read data for each color on the same line without errors.

Abstract: A method and apparatus usable in an image forming apparatus, comprising a photoreceptor, and a plurality of exposing devices having a plurality of light emitting elements arranged therein for exposing the photoreceptor, wherein the plurality of exposing devices include at least two exposing devices having a distribution tendency similar to the plurality of light emitting elements.

Abstract: A method of registering a print between print stages in a printing system is provided. The method comprises: printing a first part of a digital image on a substrate with a first print engine, wherein the first part of the digital image includes a plurality of reference features; scanning image content on the substrate as it is readied for the second print engine; determining the actual positions of the reference features; using the actual positions of the reference features to determine desired adjustments for the second part of the digital image; applying electronic registration according to the desired adjustments to modify image content of the second print to be aligned with content already on the substrate; and printing a second part of the digital image on the substrate.

Abstract: An approach is provided for managing the processing of print data at a printing device based upon available consumable resources. A printing device includes a print process configured to determine consumable resources that are currently available at the printing device. The print process is further configured to determine which print data is to be processed based upon the consumable resources currently available at the printing device and the consumable resources required to completely process each of the print data. Print data that can be completely processed using the currently available consumable resources are selected for processing. The print process may also be configured to cause a notification to be provided to a client device to indicate the consumable resources currently available at a printing device and/or that insufficient consumable resources were available to process particular print data and to recommend other consumable resources to process the particular print data.

Abstract: An image recording apparatus includes an image forming section, a first frame for supporting the imager forming section, a second frame for supporting the first frame loosely, and a supporting section disposed on an apparatus body for supporting the second frame in a rotatable manner, wherein the first frame moves in association with a rotation of the second frame.

Abstract: A semiconductor device, a print head comprising the semiconductor device and an image forming apparatus comprising the print head are supplied which are able to reduce cost through miniaturizing element size and minishing chip area. The semiconductor device comprises a plurality of light emitting elements; and a shift register circuit that has output terminals respectively corresponding to the plurality of light emitting elements and stores emitting-light instruction data of the light emitting elements, wherein each light emitting element has a first electrode and a second electrode to that lightening electricity of the light emitting element flows, and a third electrode for controlling the light emitting element whether to emit light, the output terminals of the shift register circuit are respectively connected with the third electrodes of the corresponding light emitting element.

Abstract: A method and system for printing documents with one or more embedded security features is provided. Security features are embedded in the document by co-printing magnetic and non-magnetic toner on a receiver before fixation by a fixing station. The combination of magnetic and non-magnetic toners in the image results in image elements that easily show alteration or are undetectable by visual means.

Abstract: An image recording apparatus includes an image forming section, a first frame for supporting the imager forming section, a second frame for supporting the first frame loosely, and a supporting section disposed on an apparatus body for supporting the second frame in a rotatable manner, wherein the first frame moves in association with a rotation of the second frame.

Abstract: The exposure apparatus is provided with: an optical member; and a holding member that holds the optical member. Both end portions of the optical member are held by the holding member with a first adhering unit that is cured by light irradiation for first duration and a second adhering unit that is cured by light irradiation for second duration which is longer than the first duration.

Abstract: An image forming apparatus includes: an image holder; an exposure member that has an exposure portion exposing the image holder; a first positioning unit that determines a distance in a first direction, which is a direction of an optical axis of the exposure member, between the exposure member and the image holder; and a second positioning unit that determines a position of the exposure member with respect to the image holder in a second direction being a direction of an axis line of the image holder, and a position of the exposure member with respect to the image holder in a third direction being perpendicular to both the first direction and the second direction, and that determines the distance between the exposure member and the image holder at a position substantially closer to the exposure member than the position of the first positioning unit.

Abstract: A method of printing using an image-on-image device that includes a photoreceptor, including monochrome exposing the photoreceptor or monochrome charging the photoreceptor, wherein monochrome exposing the photoreceptor includes charging the photoreceptor, successively exposing the photoreceptor in a monochrome mode using a plurality of exposing devices during a single revolution of the photoreceptor relative to the exposing devices, and developing a monochrome image on the photoreceptor; and monochrome charging the photoreceptor includes successively charging the photoreceptor via a plurality of charging devices during a single revolution of the photoreceptor relative to the charging devices, exposing the photoreceptor using an exposing device, and developing an image on the photoreceptor. A marking device capable of implementing the method of printing.

Abstract: A method of pixelized image formation on a photosensitive surface, comprising: providing relative motion of the photosensitive surface relative to a multiplicity of light sources, such that pixels on the surface pass a plurality of said light sources; and exposing a plurality of the pixels of the surface to one or more, but fewer than the plurality, of said light sources, such that the exposure of the exposed pixels is the same.

Abstract: A printing system and method is provided for adjusting image on paper (IOP) misregistration in a printing device. The method includes initiating marking of a substrate with a test pattern, the test pattern having at least one feature, and the marked substrate including at least two features including the at least one feature of the test pattern; sensing in a first sensing operation, as the substrate is transported in a process direction, a first feature of the marked substrate; sensing in a second sensing operation, as the substrate is transported in the process direction, a second feature of the marked substrate, wherein at least one of the first and second features is included in features of the test pattern; measuring a time differential between the sensing of the first and second features; and determining an IOP misregistration characteristic based on the measured time differential.

Abstract: A method for imaging a printing form is particularly suited for a printing form exposer or a printing unit of a press. A plurality of light sources produce image points in a row on the printing form whose spacing is greater than the minimum image point spacing. A first partial row of image points is produced with a first subset of the light sources and a second partial row is produced with a second subset. During a number of imaging steps, at least some of the image points of in each case one of the subsets is placed along the row in positions between image points of the respective partial row, produced in a previous imaging step, and in which, after the number of imaging steps, in a further imaging step, image points of the first subset are placed along the row at positions between image points of the second partial row from the preceding imaging step.

Abstract: A line head module includes a line head in which a plurality of organic EL elements is arranged, a lens array made by arranging lens elements that form an image of light from the line head. A first chamber formed on the side of the lens array of the line head is sealed.

Abstract: The present invention aims to effectively perform image data transfer between an image generation controller and an image processing controller in either of color image printing and black-and-white image printing. Respective signal lines of Y, M, C and K are provided in a video interface formed between a PDL controller and the image processing controller. When the color image is printed by a printer of one-drum structure, data of a one color for four lines are simultaneously transferred by using the four signal lines, and this transfer operation is repeated for one page and for the four colors. When the black-and-white image is printed, black data for the four lines are simultaneously transferred by using the four signal lines, and this transfer operation is repeated for one page.

Abstract: At least sequential current and subsequent sheets of a print job are received in a document processing system. Each sheet includes a front image and a back image. The received sheets are scheduled to be printed with at least one of a first and a second sequence by at least one of a first and a second marking engine based on a comparison of the image content in corresponding selected portions of each front and back image.

Abstract: A control part comprises a division location setting part for setting a division location based on an image data; a scan start position setting part for setting scan start positions of recording heads based on the division location; an image data division part for dividing an image data by the division location; and a head movement control part for controlling movement of the recording heads. The division location setting part sets a division location in a blank area having no pixel to be recorded in the primary scanning direction, in the case of publication printing, in a center margin area between page data. Since the recording heads perform scanning concurrently their respective areas that are divided by the division location, no deterioration in image continuity occurs between the recording heads. This permits an image recorder, though having plural recording heads, capable of performing concurrent recordings without loss of continuity.

Abstract: A replaceable component is installable in and removable from a printing device and contains one or more supplies used in printing by the printing device. A memory and a port are in the replaceable component. Data that characterizes usage of the one or more supplies in printing by the printing device is stored in the memory. The data can be transferred through a cable from the port to a host computer using a data transfer protocol of the port.

Abstract: An image forming apparatus and a control method for the apparatus are disclosed. In this image forming apparatus which has a printing unit selectively using a desired one of a plurality of types of ink cartridges and can receive monochromatic and color facsimile images, appropriate ink remaining amount detection or appropriate received facsimile image printing control can be performed in accordance with the type of received image and the type of loaded cartridge. In receiving/printing monochromatic and color images, a received image is discriminated as a color or monochromatic image, and the type of cartridge currently loaded into an ink-jet printing unit capable of performing printing operation by selecting one of a plurality of printing capabilities is discriminated. In accordance with these discrimination results, control is performed to automatically print the received image using the printing unit or stored it in an image memory or the like.

Abstract: An image forming apparatus includes an electrophotographic developing device, a photosensitive body, a precharger for precharging the photosensitive body, and exposing units of two optical systems with different light amount distributions, which are provided for one photosensitive body for forming electrostatic latent images on the photosensitive body. The exposing units are selectively used.

Abstract: It is intended to provide an image forming apparatus and image forming method capable of partial magnification corrections on various partial variations of magnification as well as constant and uniform positional shift regardless of any sections. A modulated image clock of a reference color (black) is generated from a clock generated at an image clock generating section 23 and an address is generated at an address generating circuit 36 basing on the modulated image clock. Output sections 30 for respective colors other than the reference color read out correction coefficients from correction coefficient memories 15 of respective colors following the address generated. Frequency modulator circuits 31 modulate image clocks in accordance with correction coefficients. PWM 33 outputs a driving pulse to a laser driver 6 basing on modulated image clocks synchronized with a reference signal 40 by synchronizer circuits 32 and inputted image data.

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

Abstract: Each pixel receives a digital picture data having a multi-gradation data. A line composed of printing pixels having a thickness difference of multi-gradations is obtained on a recording paper by controlling whether or not there exist ink transcription by each gradation with a line head. A digital printer of printing a picture by recording a plurality of lines on a recording paper with scanning by the line head, comprising counting devices (5-1, 5-2) for counting a number of pixels to print at each gradation, dividing devices (9-1, 9-2, 12-1, 12-2, 13-1, 13-2) for dividing all pixels into several groups in accordance with the counting devices and deciding devices (10-1, 10-2, 11-1, 11-2) for deciding a number of groups. A range of grouping and as number of groups can be changed so as for a number of printing pixels in every group to be equal to a predetermined number of simultaneous turn-on pixels.

Abstract: In order to obtain image with high resolution and eliminate the nonuniformity of written latent images and toner images by achieving the formation of electrostatic latent images corresponding to the widths of driven writing electrodes, a writing head 3 has a plurality of writing electrodes 3b which are arranged along the axial direction of an image carrier 2 such that the writing electrodes 3b are in contact with the image carrier, wherein the writing electrodes 3b are aligned in the axial direction Y and the circumferential direction X of the image carrier 2 such that the writing electrodes 3b which are most adjacent to each other in the axial direction Y are not overlapped with each other as seen in the circumferential direction of the image carrier. (FIG.

Abstract: Disclosed is a printing system in which unauthorized copying and reproduction are prevented by making it easy to identify the source which created or manipulated image data to be reproduced and outputted. In accordance with this printing system, image data is entered from a personal computer that generates the image data, attribute information concerning the personal computer and a printer for forming an image is acquired, identification information which specifies the personal computer and the printer is generated based upon the attribute information, this identification information is added to the image data, and an image is printed using the image data to which the identification information has been added.

Abstract: A printable laminate film having improved resistance to delamination or separation of the layers of the laminate. The invention concerns the use of a new combination of ink absorber materials and adhesive materials in a single ink recording layer on a carrier film. The adhesive is selected from the group consisting of polyurethanes, vinyl ester copolymers, acrylic copolymers and ionomeric copolymers, and the ink absorber is selected from the group consisting of blends of cationic polymers, blends of cationic polymers and cellulose ether, and polyvinyl alcohol.

Abstract: According to the present invention, writing electrodes 3b of a writing device 3 are kept in contact with a latent image carrier 2 with a small pressing force by a weak restoring force of a substrate 3a. An electrostatic latent image is written on the latent image carrier 2 by applying or removing charge relative to the latent image carrier 2 which are already uniformly charged by a charge control device 7. The application or removal of charge is conducted via charge-transfer between the latent image carrier 2 and the writing electrodes 3b which are in contact with each other. The electrostatic latent image is developed by a developing device 4 to form a developing powder image and this developing powder image is transferred to a receiving medium 5 such as a paper by a transferring device 6.

Abstract: In a process and apparatus for decorating an article, printing ink or electrostatic charges is or are applied in dependence on a digital program in dot form to the article carried by a holder, with individual dots going together to at least form a partial pattern or image. In the case of the latent pattern formed by electrostatic charges, it is then brought into contact with ink particles to form the decoration. In both cases the article is transported along a transportation path through at least one print station provided with an inkjet print head or an ionographic print head, the print head being controllable in dependence on the digital program. The individual nozzles or the electrodes of the respective print head are actuated in accordance with the digital program which is called up for example in dependence on the transportation movement of the article.

Abstract: Writing electrodes of a writing device are kept in contact with a latent image carrier with a small pressing force by a weak restoring force of a substrate. An electrostatic latent image is written on the latent image carrier by applying or removing charge relative to the latent image carrier which is already uniformly charged by a charge control device. The application or removal of charge is conducted via charge-transfer between the latent image carrier and the writing electrodes which are in contact with each other. The electrostatic latent image is developed by a developing device to form a developing powder image and this developing powder image is transferred to a receiving medium such as a paper by a transferring device. Since the writing electrodes are employed as the writing device, the apparatus can be manufactured smaller and simply and can steadily write an image.

Abstract: According to the present invention, writing electrodes 3b of a writing device 3 are kept in contact with a latent image carrier 2 with a small pressing force by a weak restoring force of a substrate 3a. An electrostatic latent image is written on the latent image carrier 2 by applying or removing charge relative to the latent image carrier 2 which are already uniformly charged by a charge control device 7. The application or removal of charge is conducted via charge-transfer between the latent image carrier 2 and the writing electrodes 3b which are in contact with each other. The electrostatic latent image is developed by a developing device 4 to form a developing powder image and this developing powder image is transferred to a receiving medium 5 such as a paper by a transferring device 6.

Abstract: The recording sheet supporting surface of the transport belt comes in contact with the photosensitive drums for cyan, magenta, yellow, and black in the color copy mode, and is separated from the photosensitive drums aside from the photosensitive drum used for forming a black image in the monochrome copy mode with the image forming units for cyan, magenta, and yellow not being activated. With this separating operation, the distance on the transportation path of the recording sheet measured from the synchronizing roller to the transfer position of the photosensitive drum used for forming a black image in the monochrome copy mode is longer than in the color copy mode. Thus, the start time of scanning the surface of the photosensitive drum used for forming the black image is delayed in the monochrome mode according to the difference in distances between the color and monochrome modes.

Abstract: A printer includes LED heads and head controllers. Each head controller transfers items of data to a corresponding head over a set of common buses. The LED head has a receiver activated by a corresponding head selecting signal. In one configuration, the common buses may include a selector bus over a data bus. Image data and a group of signals are alternately transferred over the data bus, the group of signals including a latch signal for latching the image data into a corresponding head and a strobe signal for driving a corresponding head in accordance with the image data. The selector signal allows the receiver to direct the image data and the group of signals into separate data paths. In another configuration, the control signals may further include an image clock and a control clock.

Abstract: An electrographic recording apparatus method includes a primary image forming member (PIFM) such as a web or drum that moves in a process direction. An electrographic writehead has a row of spaced electrodes arranged with the row being transverse of the process direction. The electrodes are selectively activated to establish respective electrical fields for recording of a respective row of pixels on the PIFM. The writehead faces a first surface of the PIFM and is positioned in contact with or closely adjacent the first surface to establish the respective electrical fields through the PIFM. A development station includes electrostatically charged toner particles in the form of a nap that selectively deposits the toner particles on a second surface of the PIFM directly opposite the series of spaced electrodes so that the toner particles are electrostatically selectively attracted by the respective electrical fields to develop the respective pixels to form a toner image on the second surface of the PIFM.

Abstract: A color electrostatic recorder of a single path system includes electrostatic recording heads conveyed in sliding contact with a recording medium for forming electrostatic latent images, developers provided in pairs to the electrostatic recording heads for developing the electrostatic latent images, and adjustable sliding contact of the recording medium with the electrostatic recording heads. The electrostatic recording heads and developer are provided in series as required, the radii of surface curvature in the electrostatic recording heads are made larger on the downstream side in the moving direction of a recording medium than on the upstream side, and the pressure of electrostatic recording heads on the recording medium is adjustable according to the type of the recording medium.

Abstract: A color copy machine is equipped with four image forming sections for forming images of different color components based on image data items relating to separated color components. A conveyance belt is provided below each image forming section. To avoid forming of a displaced image on a recording paper sheet P conveyed by the conveyance belt, pattern data for prevention of a displaced image is synthesized with image data. Each image forming section forms color patterns on predetermined portions of the conveyance belt on the basis of the synthesized data. The main-scanning directional displacement of each color pattern can be detected by comparing the numbers of those sensed line segments of the patterns which are sensed by a sensor. Then, the image forming positions are adjusted so that the numbers of the sensed line segments will be equal to each other.

Abstract: A copier, scanner, or printer has serial scanning and/or printing heads. A uniform relative motion is maintained in a longitudinal direction between the head(s) and the scanning and/or printing media. The head(s) move cyclically back and forth at an acute angle to the longitudinal direction, so that each scanning element and/or each printing element scans or prints a pixel line perpendicular to the longitudinal direction. The acute angle and the rate of relative uniform motion are preferably adjustable according to the width of the area to be scanned or printed. For color copying, scanning, or printing, the scanning and/or printing elements are grouped according to color, and are aligned so that the same pixel lines are scanned or printed in different colors.

Abstract: An electrostatographic reproduction method and apparatus includes an electrostatic recording member moving in a process direction. A plurality of recording elements on a writer imagewise expose the recording member to form electrostatic latent images on the recording member. The writer includes driver circuitry for actuating selected recording elements. The exposed recording member is then moved through a development station to develop the latent images. The developed images are transferred to a record member. An operator selectable adjustment controller is manually adjusted for generating adjustments in operation of the recording elements to compensate for a misalignment of a process station in the apparatus.

Abstract: A method and apparatus for reproducing color images using a non-interactive pyroelectric imaging process is disclosed. More specifically, the present invention is used to generate multiple layers of toner on the top surface of a pyroelectric imaging member without physical contact to the imaging member top surface. The ability to generate a composite image with different materials in this manner enables printing machines to use a pyroelectric imaging process to generate color images in the image on image (I-O-I) mode.

Abstract: A printing system includes a plurality of print engines; a raster printer controller having a processor for generating the rasterized bitmap data; and a plurality of print engine communication devices, where each of the print engine communication devices are coupled to a corresponding one of the print engines to provide the rasterized bitmap data to the corresponding print engine. The print engine communication devices are coupled together with the raster printer controller in a daisy chain configuration by a data link. Each of the print engine communication devices includes a message processing circuit that is adapted to monitor data received from raster printer controller, execute commands embedded in data received, update a bitmap data memory storage buffer in the print engine communication device with rasterized bitmap data embedded in the data received from the raster printer controller.

Abstract: A printing apparatus in which one of two types of printing heads with opposite scan directions is selectively mounted and the mounted printing head is supplied with printing data representing an image to be printed, thereby printing the image, includes a printing data transfer unit for transferring the printing data to the mounted printing head in one of an order from a beginning to an end of a scan line and an order from the end to the beginning of the scan line; a head recognition unit for recognizing the type of the mounted printing head; and a transfer control unit for enabling the printing data transfer unit to transfer the printing data in the order associated with the type of the mounted printing head recognized by the head recognition unit.