Abstract: An optical scanner has a light source device for emitting an approximately parallel light beam polarized approximately linearly; a deflector for deflecting the light beam from this light source device toward a scanned face; an image forming optical system including an optical element having a focal length variable by an electrooptic medium, the image forming optical system being arranged between the light source device and the deflector to form the light beam from the light source device as an image in the shape of a spot on the scanned face; a controller for controlling the focal length of the image forming optical system; and an electrode pair disposed in the electrooptic medium of the optical element, the arrangement position and shape of the respective electrodes being constructed such that a convergent position of the emitted light can be changed when a voltage is applied by the controller between these electrodes; the controller controlling the focal length of the image forming optical system such that

Abstract: A method for transferring a viscous substance includes the steps of providing a viscous substance having an adhesive characteristic which changes in correpondence to the polarity of a voltage applied thereto. The viscous substance had an adhesive characteristic when no voltage is applied thereto and its adhesiveness is reduced when a voltage is applied thereto. The method further includes the steps of disposing the viscous substance between first and second electrodes and applying a voltage between the first and second electrodes to thereby substantially attach the entirety of the viscous substance to one of the first and second electrodes.

Abstract: A method of vapor jet printing is described, along with several embodiments of apparatus for practicing such method. The vapor phase of a sublimable dye is mixed with a carrier gas. The resulting mixture is then jetted toward a recording medium. The carrier gas in indirectly heated by the sublimable dye to maintain the latter in its vaporous state during its travel to the recording medium. One embodiment of the apparatus includes a removable cartridge for the sublimable dye which enables color interchangeability and a limited downtime for dye recharging.

Abstract: An image forming method in which a recording head is step-driven by a stepping motor to perform vertical scanning, and a recording drum, around which a light-sensitive recording material is wound, is rotated to conduct horizontal scanning to form an image onto the light-sensitive recording material. In the image forming method, the horizontal scanning starts during residual vibration of the recording head after the stepping driving of the stepping motor stops and after a predetermined period of time from the start of the step driving. Accordingly, although horizontal-scanning lines meander due to the residual vibration, all of the horizontal-scanning lines are brought to their respective loci which are identical.

Abstract: A recording medium is provided which includes an ink-transporting layer and an ink-retaining layer, the ink-transporting layer being chiefly comprised of particles and a binder, wherein d.gtoreq.0.1 .mu.m when an average value of primary particle diameter of the particles is assumed as d, and the volume of the particles whose particle diameter (x) is included in the range of d/2.ltoreq.x.ltoreq.2d is in a proportion of 90% or more of the whole particles. The purpose of this particle and binder arrangement is to provide a recording medium having high gloss and image density, and one particularly having a greatly superior ink absorbing ability and capable of giving recorded images of high image quality that are free from feathering and having high recording density. An ink jet recording process employing the above-mentioned recording medium is also provided.

Abstract: A multipoint recorder with a slow effective chart speed is operated to provide good visibility for the most recent record. A number of consecutive values for each point are scanned and stored. These values are recorded by a high speed printing mechanism during a first period of the recording cycle after which the chart is advanced forward for the remaining period of the recording cycle to a point which makes that record easily visible. At the end of the recording cycle the chart is retracted to start the next printing period with the printing mechanism at a point which corresponds to that required make the record look like a continuous line and to provide the desired time scale along the chart. To accomplish this the cycle time is coordinated to the chart speed and the number of consecutive scans recorded during each recording cycle.

Abstract: A photosensitive and heat-sensitive polymer having conjugated polyenes and sulfonic acid groups and an absorbance ratio of a strong band in the region of 1200 cm.sup.-1 to 1300 cm.sup.-1 assignable to sulfonic acid groups adjacent to conjugated polyenes of at least 3 sequence lengths to a strong band near 1050 cm.sup.-1 assignable to sulfonic acid groups in the IR spectrum of at least 0.6.

Abstract: An apparatus and method is disclosed for controlling the temperature of a thermal print head and individual dot elements thereon, thereby optimizing print quality and reducing the thermal and electrical stress on the thermal print head. Hysteresis control determines the amount of energy supplied to each dot element in the thermal print head. Peak temperature control determines the width of the pulses supplied to the dot elements on the thermal print head. Pre-heating control raises the temperature of each dot element when the dot element has been idle for a predetermined period. Substrate temperature control maintains the temperature of said thermal print head at a predetermined value.

Abstract: A piezoelectric pump or equivalent transducer is mounted on or within an ink jet printhead and is used to modulate the frequency or amplitude, or both, of oscillations of a liquid meniscus at a liquid ejection orifice of a nozzle plate. The liquid meniscus at the orifice has a natural resonant frequency and amplitude with respect to its equilibrium position, and the above modulation is performed in a controlled timed relation with respect to the phase of the natural oscillations of the meniscus at the liquid ejection orifice.

Abstract: Novel impulse ink or bubble jet inks are disclosed which comprise 90-99.9% by weight of aqueous sol-gel medium and 0.1-10% by weight colorant. The inks are thermally reversible sol-gels which are gels at ambient temperatures and sols at temperatures between about 40.degree.-100.degree. C.

Abstract: A multi-jet print head for a continuous ink jet printer has its individual ink jets formed electrostatically instead of using a row of individual nozzles. Ink is supplied continuously through a slot in an electrically conducting body or to an elongated edge portion of such a body, while a strong electrostatic field is applied to draw off the ink as an array of parallel cusps. These break up at their tips to form a stream of ink drops which can then be deflected in known manner. The electrostatic field preferably has a reinforcing secondary field superimposed on it, which is cyclically varied at a suitable ink drop production frequency to synchronize formation of the ink drops at each of the cusp tips. This enables means for deflecting the drops to be synchronized with the moving drops for consistent deflections and corresponding optimum resolution.

Abstract: An image forming apparatus comprises: an electroconductive substrate; an electroconductive member disposed opposite to the electroconductive substrate; a plate-forming unit for forming an insulating pattern on the electroconductive substrate; a supplier for providing a recording material between the electroconductive substrate and the electroconductive member, the recording material being capable of changing its adhesiveness corresponding to the polarity of a voltage applied thereto; and a voltage source for applying a voltage between the electroconductive substrate and the electroconductive member.

Abstract: A thermal ink jet printer is disclosed having a printhead with a passageway therein for the circulation of a cooling fluid therethrough. The passageway is parallel and closely adjacent the array of bubble generating heating elements. When the printhead is composed of mated silicon channel and heater plates, the passageway is formed in one embodiment by forming a groove in the heater plate surface opposite the one containing the heating elements and addressing electrodes followed by the mating of a silicon sealing plate having inlet and outlet openings etched therein. Tubes for circulating a cooling fluid, such as ink, are sealingly attached to the inlet and outlet openings. In an alternative embodiment, the groove may be formed in the sealing plate or in both the sealing plate and the printhead heater plate. In another embodiment, the passageway for the cooling fluid is provided by etching a channel in a thick film layer deposited on the heater plate surface opposite the one with the heating elements.

Abstract: Disclosed is an integral ink jet print head having an improved design. An ink reservoir wall at the base of print head guides a flow of ink from a remote reservoir. Ink is drawn by capillary action past flow restrictors and an ink channel into an ink heating zone. The ink heating zone is a chamber residing below an integrated ink heating structure which has been fabricated, using processes including photolithography, directly on the underside of an orifice plate. An orifice is located to one side of the ink heating zone. The ink heating structure housing the ink heating zone is a combination of thin layers deposited directly on the orifice plate. The multilayered structure includes an insulating layer of silicon dioxide, a resistive layer of tantalum aluminum alloy, and a top conductive layer formed of gold. The invention provides a single integrated print head that combines the separate elements of the previous designs into one unit having many ink jets on one ink jet print head.

Abstract: A hybrid type thermal ink jet (TIJ) pen and method of manufacture wherein a plurality of individual thin film ink jet printheads, each including an orifice plate, are selectively spaced on and secured to an insulating substrate having ink feed ports therein which supply ink to the printheads. Buss lines and integrated circuit driver-decoder packages may be mounted in a planar fashion with respect to the printheads and electrically interconnected to drive the printheads.Alternatively, the individual printheads may be mounted on a unitary insulating support and ink feed structure such as a ceramic substrate and interconnected to off-substrate TIJ driver circuitry by way of printed or silk-screened electrical leads. These leads may be laid down in a controlled pattern on the surface of the ceramic substrate and used to interconnect bonding pads on the TIJ printheads with the above off-substrate driver circuitry and power supplies.

Abstract: In a color ink jet printing system, an image superpixel (84, 86, 88) consists of a 2 by 2 array of cells (1-4), each cell corresponding to a pixel area on the substrate (80). Each pixel (55) of graphics data is processed to form a 2 by 2 array of bit image data (40), for printing a corresponding superpixel image (68). A superpixel configuration (86), indicating cell location and color of drops of ink for forming a superpixel image, is defined for each desired image color. Superpixel configurations control printing so that drops of ink (Y,M,C) are deposited only an a diagonally adjacent pair of cells (1,4), with no more than two drops of ink per cell, and no more than three drops of ink per superpixel. This superpixel strategy provides for printed images (62,64) perceivable as having the desired image color and having good color saturation, while minimizing bleed across color field boundaries (66).

Abstract: A device for driving a thermal print head having a plurality of heat-producing elements arranged in the form of a single array for use in a thermosensitive or thermal transfer recording apparatus is provided. The drive device includes a void data counter for counting void data in the data of an image signal for each of the plurality of heat-producing elements and an adjusting unit for adjusting the level of a preheat energy to be supplied to each of the plurality of heat-producing elements in accordance with the void data count for the corresponding heat-producing element.

Abstract: A method of reducing the wettability of non-vitreous surfaces, and ink jet recording heads including a surface having reduced wettability, are provided wherein a layer of cured siloxane is formed on the non-vitreous surface and a layer comprising at least one fluorosilane is formed on the siloxane layer.

Abstract: A thermal transfer recording method is disclosed using a thermal transfer material in which a heat-transferable ink layer is deposited on a support, this ink layer being formed so that its melt viscosity decreases from the support side toward the surface side. Recording is carried out by superposing the thermal transfer material over a recording medium and heating the thermal transfer material in accordance with an image signal by means of a recording head. The recording head has a substrate on which a heat-generating member is located. The distance from the center of the heat-generating member to the trailing edge of the substrate is no more than about 1 mm. The thermal transfer material is separated from the recording material immediately after heating.

Abstract: The water-fastness and smear resistance of prints from inks in which a reactive moiety is attached to a chromophore are improved if the prints are treated with a strong base solution. Preferably, the paper is first treated with the base solution and then printed with the ink.

Abstract: A heat sensitive copy system uses a magnetic thermal transfer ribbon to transfer images onto an adjacent medium and near infra-red energy is used to transfer the images from the medium onto thermal paper or onto translucent paper for producing multiple copies in a manner which is not thickness sensitive.

Abstract: In a liquid injection recording apparatus wherein recording liquid is discharged from discharge ports provided in the discharge port surface of a recording head to make flying liquid droplets to thereby accomplish recording, liquid-repellent process means capable of applying a liquid-repellent agent for repelling the recording liquid adhering to the discharge port surface is provided to the discharge portion surface from a position capable of being opposed to the discharge port surface.

Abstract: In the embodiment of the hot melt ink supply unit described in the specification, a block of solid hot melt ink has a peripheral surface formed with a key configuration and a handle is removably connected to the block by a threaded projection. After insertion of the block into a correspondingly keyed opening in a heated reservoir, the handle is turned to separate the handle portion from the block of solid ink. A container provided with a removable seal encloses the block of solid ink and handle to protect the ink from contamination.

Abstract: A pulse of current of several hundreds of volts is established between two electrodes immersed in a resistive liquid. By concentration of the current at the end of one electrode, which is bonded onto an insulating support, a volume of liquid in contact with the end of this electrode is vaporised, causing an abrupt drop in current. Because of the voltage of the pulse, which is several hundred volts, a greater current re-establishes itself immediately across the volume of vaporised liquid, as a result of a sort of ionization of the vapor, causing superheating and energy sufficient to expel a droplet of liquid through an opening provided in a membrane. In order to limit the energy of the superheating phase and control the size of the droplets, the current of the energizing pulse is limited.

Abstract: A system for selectively shifting the phase of drop charging along the array of ink jets of a continuous ink jet printer by producing a replicate signal of the drop stimulation signal; selectively shifting the phase of the replicate signal to provide a phase control signal; synchronizing a media feed tachometer signal to the phase control signal to produce a print enable signal; and controlling address of the charge electrodes with the print enable signal. The system further includes a selection mode wherein drop charge phase can be made random by selecting synchronization with the media feed tachometer signal.

Abstract: Suction recovery device for use in an ink jet printer provided with an ink jet recording unit for emitting ink to a recording surface of a recording medium and a cap member to face the recording unit at a determined position, comprising a suction unit communicating with the cap member and a vent unit communicating with the cap member at a position different than the position where the suction unit communicates with the cap member for opening and closing the interior of the cap member to the atmosphere.

Abstract: An electronically controlled marking system is provided to impart an ink spot to a stationary or moving target. The system includes an electronic control module connected to a high-pressure gas valve to control the passage of high-pressure gas to an ink spot maker, the electronic control module also being connected to a low-pressure gas valve to control the passage of low-pressure gas to the ink spot marker. Following the initiation of an ink spot marking cycle, low-pressure gas is applied to atomize ink within the ink spot marker; high-pressure gas is applied to force open a valve within the ink spot marker, thereby allowing ink to be ejected by the low-pressure gas toward the target; the high-pressure gas is removed to terminate the ejection of ink from the output nozzle, the low-pressure gas still being applied to force any remaining ink from the output nozzle; and the low-pressure gas is removed.

Abstract: A multiple pass complementary dot pattern ink jet printing process for enhancing the uniformity and consistency of dot (drop) formation during color ink jet printing. Such enhancement in turn directly affects and improves the total print quality over a color printed area by minimizing the undesirable characteristics of coalescence, beading, hue shift, bending, cockeling and color bleed when printing on both transparencies and plain or special papers. Using this process, successive printed swaths are made by depositing first and second partially overlapping complementary dot patterns on a print media. Simultaneously, the dot spacing in coincident dot rows within the overlapping portions of the dot patterns is alternated between dots in the first pattern and dots in the second pattern.

Abstract: A method and apparatus for priming a thermal ink jet pen is disclosed. Using an ink reservoir fabricated of a foam material, forced air pressure applied to the foam causes ink therein to flow through the foam and into the printhead. A holder for a rubber air bladder operates in conjunction with a pen cartridge holder whereby an air hole in the reservoir container is aligned with the bladder. Manually pushing the cartridge against a spring results in a squeezing of the bladder, causing air to exert a compression-like pressure directly on the foam reservior.

Abstract: An image is recorded on an image recording material by energizing a thermal head having a plurality of heating elements with input image data. As the image recording material, there is employed a heat sensitive recording material comprising a support coated with a coating solution which makes an unheated area colored and a heated area transparent in a colorless or light colored manner. An image is recorded on the heat sensitive recording material with the thermal head by processing the image data through negative-positive reversal and applying the processed image data to the thermal head. The image data are processed through negative-positive reversal by converting the image data based on a function which has the input image data as a variable and a negative differential coefficient.

Abstract: An optical data recording medium provided with a recording layer, the recording medium having excellent durability to light and heat, superior writing sensitivity and a high C/N value, wherein at least one a group of anion selected from a group of hexafluorophosphate ion (PF.sub.6 .sup.-), trifluoromethane sulfonate ion (CF.sub.3 SO.sub.3 .sup.-) or thiocyanate ion (SCN.sup.-) is present as the anion in an indol cyanine dye having a methyne chain present in the recording layer of the optical data recording medium.

Abstract: An ink jet print cartridge includes an ink reservoir, a print head for ejecting ink from the reservoir and first and second pressure control mechanisms for limiting the reservoir underpressure. The first pressure control mechanism limits reservoir underpressure by controllably introducing replacement fluid (i.e. air or ink) thereto. The second pressure control mechanism limits reservoir underpressure by changing the volume thereof. The two pressure control mechanisms cooperate to regulate the underpressure in the reservoir at a desired value over a broad range of environmental excursions and permit use of a volumetrically efficient package.

Abstract: Multiple images may be written simultaneously onto at least one photosensitive surface by modulating first and second laser beams in accordance with image information corresponding to first and second images. The first beam is directed onto a scanning mirror at a first angle of incidence A.sub.1, and the second beam is directed onto the same scanning mirror at a second angle of incidence A.sub.2. The first beam is focussed from the scanning mirror onto the photosensitive surface to write the first image thereon. The second beam is focussed from the scanning mirror onto the liquid crystal surface to write the second image thereon spatially remote from the first image.

Abstract: A method of operating a system for jetting phase change ink comprises effecting a solid to liquid phase transition of the ink by elevating its temperature, ejecting a first volume of liquid ink towards a target, lowering the temperature of the ejected ink to cause it to solidify after contact with the target and the contacting the first volume of ink with a second volume of similarly jetted ink in a liquid state so that the two volumes are superimposed. Thereafter, the second volume of ink is caused to undergo a liquid to solid transition by lowering its temperature.

Abstract: A transfer recording medium comprises a transfer recording layer, which causes an irreversible change in transfer characteristic when provided with plural kinds of energies, at least one of which is applied imagewise, to provide a transferable portion or latent image portion in the transfer recording layer. The transferable portion is then transferred to a medium such as plain paper to form a transferred image thereon, which is then fixed by application of at least one of light, heat and pressure. The fixing step is effective, e.g., in providing a recorded image with improved stability against environments and elapse of time, color reproducibility and color densities through functional separation from the transfer step.

Abstract: A continuous-tone thermal printer includes a transport mechanism for advancing a print medium past a thermal print head while continuous-tone image information is being printed, line-by-line, on the medium. To increase the rate at which thermal prints are produced, the printer includes asynchronous motor-control apparatus for selectively accelerating the movement of the print medium relative to the print head to quickly locate the print head at the start of a new image line immediately following the printing of that pixel(s) having the highest image density in the preceding image line. Preferably, such motor-control apparatus includes a digital signal processor which determines the maximum pixel density on each line. Upon printing such maximum pixel density, the digital signal processor causes a motor controller to temporarily increase the print medium velocity past the thermal print head to the start of the next image line.

Abstract: A thermal print head having a base, a glass glaze layer formed on the base by electrically-heated welding, and heating elements formed on the glass glaze layer. A manufacturing method of a thermal print head uses a furnace to accommodate molten glass and a pair of opposed electrodes disposed within the furnace to melt the glass by flowing the current. The method comprises the steps of supplying electric power across the electrodes to cause electric current to flow through glass so as to melt glass, passing an elongated base through the molten glass accommodated in the furnace to form a glass glaze layer on the base, and forming heating elements on the glass glaze layer.

Abstract: A computer program for controlling an ink-jet printer-plotter having a conventional multi-jet ink-jet cartridge operates so that when the printer-plotter is in plot mode, the jets are used in sequence, instead of conventionally always using the same jet. A different jet is used each time a new graph is started. This method lengthens the life of the cartridge by reducing stress on any one of the jets.

Abstract: A simplified color printing system and method is disclosed in which the printing system has a single applicator that is supplied with toner fluids or inks of different colors. The printing system is simplified by having a single pump employed in association with the applicator. Use of a single pump is made possible, because during a color change the pump and applicator are purged with air both before and after a wash fluid is circulated. The single pump is used to pump both the imaging fluids and the air. The present invention has application in both color electrostatic printers and copiers, and in color ink-jet printers.

Abstract: A "roofshooter" pagewidth printhead for use in a thermal ink jet printing device is fabricated by forming a plurality of subunits, each being produced by bonding a heater substrate having an architecture including an array of heater elements and an etched ink feed slot to a secondary substrate having a series of spaced feed hole openings to form a combined substrate in which said series of spaced feed hole openings communicates with said ink feed slot, and dicing said combined substrates through said ink feed slot to form a subunit. An array of butted subunits having a length equal to one pagewidth is formed by butting one of said subunits against an adjacent subunit. The array of butted subunits is bonded to a pagewidth support substrate.

Abstract: The inventon relates to a method and apparatus for marking or recording patient-related information and other necessary data in connection with X-ray imaging on a certain section of a film (6) by using a marking apparatus (2) which is movable relative to film (6). In the method, markings are made latent on film (6) in a manner that the markings become visible in connection with film development. The marking is effected as a sequence, line-directed deviation of a marking being obtained by moving the marking apparatus and the film relative to each other. The marking apparatus (2) used in the method is provided with marking elements which are brought into contact with film (6) for producing a marking on film (6), vertical deviation of alphanumerical marks included in a marking being achieved by individually controlling the operation of each marking element included in the marking apparatus.

Abstract: A printing control system includes a recording head having a plurality of heating resistor elements and a head driver for driving the recording head and calculates printing data to be sent to the head driver according to logical calculations using printing data one and two steps ahead of the current step. A printing time of the data is divided into a plurality of time intervals. The logical operations are performed according to different algorithms every time interval. The printing data of the respective time intervals are printed. By combining the data printed during the previous time intervals, the density of the current printing data is determined.

Abstract: This invention relates to a device for printing on printed products (20) which are transported past an ink jet writer (34') in an imbricated stream by means of a conveying device. A sensor (34, 35) triggers a writing operation of the ink jet writer when a printed product (20) has reached the writing area of the latter. Therefore, the printed products (20) can also be inscribed in an imbricated stream conveyed in a freely supported manner. The conveying device, in the area of the ink jet writer (34') is provided with means (12) which laterally displace the printed products individually during transportation of the printed products (20) in the imbricated stream.

Abstract: The firing resistor in a thermal ink jet pen is driven by two signals in sequence. The first signal is a warming signal, tailored to transfer a desired quantity of thermal energy to the ink in the firing nozzle. The second signal is a firing pulse tailored to vaporize ink adjacent the resistor and thereby eject a bubble of ink from the nozzle. The prewarming of the ink achieved by the warming pulse increases the volume of the vapor bubble produced by the firing pulse, thereby yielding a commensurately larger ink droplet. By varying the degree of prewarming, the droplets ejected by the firing pulse can be varied in volume, thereby effecting gray scale printing.

Abstract: A writing tool (30) carried by a write head (10) of a drawing machine is transferred to an empty station in a storage turret by bringing the write head carrying the writing tool to a transfer position, engaging the writing tool in the station of the storage device by lowering the tool, and disengaging the writing tool from the write head by moving the write head away from the transfer position. A writing tool is transferred from a station of the storage device to the write head by engaging the writing tool on the write head by bringing the write head into the transfer position, disengaging the writing tool from its station in the storage device by raising the tool, and displacing the write head together with the writing tool away from the transfer position. Tool transfer is thus provided solely by a combination of the vertical tool movements and the displacement of the write head along a given direction as normally required for the purpose of plotting on a print medium.

Abstract: A photographic contact printing process is disclosed having application in the mass production of replicate video discs from a master disc, and other applications wherein it is desired to replicate micro-detail over a relatively large area. A problem with conventional contact printing from a mask to a photographic medium is one of maintaining intimate contact over a relatively large area since dust, dirt, etc., are almost impossible to completely eliminate in any practical manner. In accordance with the present invention, a contact printing process is provided wherein intimate contact is not necessary for making high quality contact prints. The present invention recognizes that in contact printing information from a master disc to a replicate disc, the contact printing process is significantly less sensitive to imperfect contact between the master disc and the replicate disc if one employs a replicate disc comprising a photosensitive material having a certain optical properties.

Abstract: In a liquid injection recording method, the falling time of a voltage pulse applied to electromechanical converting means for generating energy for discharging liquid droplets to a recording medium is made longer under a high temperature environment than under a room temperature environment.

Abstract: A thermal recording apparatus records image data line-by-line, using a thermal head having a linear array of heating elements. Each of the heating elements is shorter in the sub scan direction than in the main scan direction. To form an image of one recording line, the feeding of a recording paper and the transfer of ink onto the paper are repeated a plurality of times--for example, two times--using the image data for that line. The excellent thermal response of the heating element constructed as above, and the use of a plurality of recording operations for one recording line image formation, provides a uniform recording density distribution curve, so that the recorded image has high image quality and is substantially free from recording density irregularity. An additional recording control employed eliminates a nonimage part which will occur due to a varied recording speed.

Abstract: An LED printhead includes an optical mask overlying the LED's to balance light outputs therefrom. The transmission density of the mask is adjusted for each LED in accordance with its respective light output to adjust same so that the light outputs from all LED's are the same. The mask comprises a UV fadeable dye whose transmission density is adjusted with a UV laser or other light source while monitoring the light output from the respective LED. The transmission density of the mask may be adjusted by a UV light source provided on the printhead during periods of nonuse of the printhead or the printhead may be removed from the recording apparatus for adjustment.

Abstract: An LED printhead includes an optical mask overlying the LED's to balance light outputs therefrom. The transmission density of the mask is adjusted for each LED in accordance with its respective light output to adjust same so that the light outputs from all LED's are the same. The mask comprises a micro-lenslet incorporating a UV fadeable dye whose transmission density is adjusted with a UV laser or other light source while monitoring the light output from the respective LED. The transmission density of the mask may be adjusted by a UV light source provided on the printhead during periods of nonuse of the printhead or the printhead may be removed from the recording apparatus for adjustment. The micro-lenslet is formed by depositing a liquid polymeric binder in droplet form over the LED and having same set to form the lenslet in situ.