Abstract: A xerographic print engine employs a photoreceptor with an image receiving surface, a printhead for directing light to the photoreceptor to produce thereon a latent image, and a developer for converting the latent image to a printable image to be transferred from the photoreceptor to a print medium during a relative motion between the photoreceptor and the print medium. The printhead has light emitting diodes disposed in plural rows arranged alongside each other on a substrate which also supports driver circuitry connecting with imaging electronics for activating individual ones of the diodes. An optical element focuses light of the diodes onto a row of the latent image, the focussing being accomplished concurrently for individual ones of the diodes located in a plurality of the rows.

Abstract: A xerographic print engine employs a photoreceptor with an image receiving surface, a printhead for directing light to the photoreceptor to produce thereon a latent image, and a developer for converting the latent image to a printable image to be transferred from the photoreceptor to a print medium during a relative motion between the photoreceptor and the print medium. The printhead has light emitting diodes disposed in plural rows arranged alongside each other on a substrate which also supports driver circuitry connecting with imaging electronics for activating individual ones of the diodes. An optical element focuses light of the diodes onto a row of the latent image, the focussing being accomplished concurrently for individual ones of the diodes located in a plurality of the rows.

Abstract: An image bar printing system, which, in a preferred embodiment, utilizes a plurality of LED arrays to provide a plurality of color images. The print bars are used in conjunction with a plurality of gradient index lens arrays which optically couple and focus the LED outputs onto a photosensitive surface. In order to maintain image-to-image registration, out of spec deviations in active write length of the image bar and scan line bow are identified and compensated for by selective deformation of one or more lens arrays in a specified manner. The lens deformation serves to reorient the position of certain of the lens elements, redirecting the transmitted LED outputs so as to shorten or lengthen the active write length, or to eliminate bow in the scan line.

Abstract: An imaging module mounting structure is used for mounting an imaging module to an imaging device that has a support member and a rotatable photoreceptor. The imaging module includes an imaging bar and a corona generating device. The imaging module mounting structure includes a pair of pivot block devices which are pivotably connected to the support member in a spaced apart relationship. The imaging bar and the corona generating device are secured to each one of the pair of pivot block devices. Each pivot block device includes a cam follower element. The pair of pivot block devices are operative to flex independently of one another while the photoreceptor rotates so that the respective cam follower elements remain in contact with the rotating photoreceptor to compensate for photoreceptor run out. A method for practicing the present invention is also described.

Abstract: A digital LED printer having a printbar control architecture that enables multi-exposure levels and multiple gray levels for a LED printbar. Alight emitting diode printbar is aligned in an image exposure relationship with a photoreceptor. Video data signal comprised of multiple bits for each pixel are applied to a register/latch. The individual bits of the latched multiple bits for a pixel are applied to AND gates. Those signals are ANDed with multiple strobe line signals that are related to the status of the printer. The outputs of the AND operation are applied to an OR gate. The output of the OR gate is used to control the illumination from a light emitting diode. Beneficially, the characteristics of the light emitting diode are measured and stored such that the current applied to the light emitting diode can be adjusted such that the illumination from the light emitting diode is at a predetermined value.

Abstract: An improved system for segregating and identifying separate job sets from a commonly stacked output of plural job sets of copy sheets sequentially generated by a printer and sequentially outputted into a sheet stacker in which they may be superposed commonly stacked. A control system selects which standard size sheet supply tray of the printer will feed the copy sheets for a selected job set, and can automatically feed and print a cover sheet of a larger size or different orientation before or after the job set copy sheets are fed. The sheet stacker may desirably stack the copy sheets of the job sets commonly edge aligned but so that at least one edge area of the cover sheets extends substantially from at least one edge of the stack of copy sheets of the job sets to provide an exposed printed banner strip for clear job sets segregation and separation even if the commonly stacked plural job sets of copy sheets are misaligned in subsequent handling.

Abstract: An image bar recording system, which, in a preferred embodiment, utilizes a plurality of LED image bars to provide a plurality of latent images which may subsequently be developed in different colors. The print bars are initially aligned so that each color image is precisely registered at the same relative position along the exposed area of a photoreceptor belt. The alignment is accomplished by adding non-image fiduciary pixels to the ends of each print bar and by forming a pair of opposed alignment apertures in the surface of the belt. Y-axis alignment of the print bars is accomplished by detecting edge locations of a first pixel and using this location to select a centrally located fiduciary pixel. The X-axis alignment is then obtained by rotating the print bar to bring a second selected image pixel into alignment as sensed through a second aperture.

Abstract: An image bar recording system, which, in a preferred embodiment, utilizes an LED image bar, with associated circuitry for recognizing which of individual LEDs comprising the print bar are out of registration in the slow scan, process direction of a moving photoreceptor upon which the image is to be recorded. Modification of the drive circuits to the individual LEDs results in energization signals being delayed to the identified, misregistered LEDs resulting in an exposure line which is in correct slow scan registration.According to another aspect of the invention, the delayed signals are selectively applied to intentionally cause a misregistered exposure line when using the image bar in conjunction with a raster output scan system.

Abstract: The temperature of LED print bars utilized in a printing system are maintained within a specified differential range, with respect to each other. Each print bar has an associated heating and cooling element. The temperature of each print bar is monitored and compared during operation. When a temperature differential greater than a preset tolerance range is detected, either the hotter operating print bar is cooled or the lower operating print bar is heated, or a combination of cooling and heating is applied to the out-of-tolerance print bars. The cooling and/or heating of the print bars is continued until the temperature differential is reduced so as to be within the preselected or predefined range.

Abstract: A color chip construction especially adapted for use in fabricating full width arrays in which the individual chip photosites consisting of a blue, green, and red photodiode shaped and positioned to provide a rectangular photosite with square sides that enhance butting of the color chip with other like color chips to form full width color arrays.

Abstract: An amalgam fluorescent lamp is designed to operate with minimum axial illumination variations when changing from an off to an on state. This is accomplished by incorporating at least three amalgam patches internal to the lamp. Two patches are located at opposite ends of the lamp, and at least a third patch is centrally located. Each patch has an associated thermistor ands external heater sleeve. The patch temperature which correlates wiht the optimum lamp operating temperature is continuously monitored and adjustments are made to the heater sleeve elements to maintain the patches at desired optimum temperature.

Abstract: A test procedure is provided for obtaining optimum illumination exposure in a document scanning an exposure system. A document illumination lamp is energized and reflection images from a document platen is transmitted through an optical system onto a linear photosensor array which is positioned in the normal exposure (image) plane. The array outputs, corresponding to individual photodiodes outputs, are amplified and processed under the control of a computer controlled software program to provide a real time display of the illumination characteristics on a display screen. The screen, in one embodiment, displays a colored bar graph which is superimposed against the horizontal line representing an in specification illumination level. The lamp and, or, illuminator, is repositioned while observing the bar graph until an optimum bar graph value is measured below the specification line.

Abstract: An amalgam fluorescent lamp is operated under high output and loading conditions by implementation of a control circuit to monitor and adjust lamp temperature. A variable density multi-element heater sleeve is connected to a controller which monitors the sleeve temperature and adjusts the power input to one or more of the sleeve segments. A separate control circuit maintains the lamp illumination output at a programmed level by monitoring a detected level of lamp output and comparing it with a pre-established reference signal.

Abstract: An electrophotographic reproduction device is described which is capable of forming images of an original document modified by information added to or replacing information of the original. A latent image of the document is formed on a photosensitive surface and a portion of the image, in a first embodiment, is maintained at the original charge level. This fully charged section is subsequently discharged in an image-wise pattern by a compact annotator device. The annotator includes an illumination source, an addressable light modulator device such as a liquid crystal panel and a lens array for forming the modulated light pattern onto the photosensitive surface.

Abstract: This invention relates to apparatus for selectively cooling an elongated lamp in a document scanning mode. A flow of cooling air is created which passes along a conduit extending along the length of the lamp to provide selective cooling draughts along various portions of the lamp envelope. The source of the cooling air is a blower directing air along the interior of a guide rail extending in parallel with the direction of movement of the lamp. One end of the conduit is thermaqlly coupled to the interior of the guide rail so as to connect a flow of cooling air passing through the guide rail interior into the interior of the conduit at all relative positions of the scanning lamp. A recoiling tape is connected between the lamp and the cooling air source, the tape being withdrawn during a scan operation to effectively seal the guide rail interior, confining the moving air in a more efficient fashion.

Abstract: The light output of a fluorescent lamp is controlled and optimized. Both the light output and the lamp voltage peak at nearly the same value of mercury cold spot temperature. Controlling the lamp voltage therefore controls the light output. Thus, when the lamp voltage is continually monitored, any decline from the peak voltage is detected and a signal is generated which reverses the instant mode of operation of a cooling device placed in proximity to the lamp cold spot. With the cooling mode reversed, the lamp voltage will rise towards the peak. The cooling mode remains unaltered until the lamp voltage falls again.

Abstract: The invention discloses a document illumination assembly which combines the functions of enhanced document illumination and illumination level control. A reflector assembly is modified by introducing a light collecting mechanism within the reflector interior, the light collector being in association with a photosensing means. The reflector performs the normal function of reflecting a portion of the incident light toward the document to enhance illumination efficiency. The reflector also enables the additional function of monitoring the axial illumination of the illumination source by permitting an axial-located radiation band of illumination to enter the reflector body and propagate along the light collecting mechanism where it is sensed by the detector. The detector generates an output signal which can be used to control the output of the illumination source.

Abstract: A low pressure gas discharge lamp is provided with a pair of high power incandescent electrodes to increase output illumination at the lamp ends. In an alternate construction, the electrodes are of high power, low emissivity and are electrically connected to a second pair of high emissivity electrodes which provide the means for enabling the mercury discharge. With this second construction, the low emissivity electrodes can act as ballast for the circuit.

Abstract: Ballasting for a fluorescent lamp is provided by one or more incandescent lamps connected in series between the line voltage source and the fluorescent lamp. Lamp operation is initiated by a triggering pulse applied to a conductive member placed adjacent the fluorescent lamp. In one embodiment, a plurality of incandescent lamps are connected in parallel and are selectively gated into the circuit depending upon exposure requirements for the lamp.

Abstract: An automatic exposure control system for a full-frame copier controls the illumination of a flash lamp in response to the reflectivity of a document to be reproduced. A photodetector senses exposure at the wall of a light housing and after sufficient exposure is reached, the light source is turned off (quenched). A compensation circuit anticipates the total energy emitted after quench (representing an over exposure potential) and terminates the light source energizing pulse so as to produce only desired exposure without over-exposure error.