摘要:
The new heater element design has a pit layer which protects the overglaze passivation layer, PSG step region, portions of the Ta layer and dielectric isolation layer and junctions or regions susceptible to the cavitational pressures. Further, the inner walls of the pit layer define the effective heater area and the dopant lines define the actual heater area. In alternative embodiments, the dopant lines define the actual and effective heater areas, and an inner wall and a dopant line define the actual and effective heater areas. Further, when the new heater element designs are incorporated into printheads having full pit channel geometry and open pit channel geometry, the operating lifetime of the printhead is extended because the added protection of the pit layer prevents: 1) passivation damage and cavitational damages of the heater elements; and 2) degradation of heater robustness, hot spot formations and heater failures well into the 109 pulse range. The printhead incorporating the new heater element design can be incorporated into drop-on-demand printing systems of a carriage type or a full width type.
摘要:
A thermal ink jet printhead is controlled to minimize missing droplets at elevated operating temperatures by varying the voltage and pulse width applied to the heater element that causes droplets to be formed and ejected. Increasing the applied voltage reduces the size of the formed droplets. At increased operating temperatures, smaller droplets minimize the introduction of air into the nozzles of the printhead upon ejection. Minimizing the introduction of air eliminates printhead misfirings and causes more consistent jetting of the ink droplets.
摘要:
An ink jet printer is configured in a hybrid architecture wherein a full width printbar is combined with a partial width color scanning assembly to provide the capability of selectively printing in black only or, alternately, of producing color prints by operating the color scan assembly exclusively. The cost of the hybrid system, when compared to a full width color system using four full width printbars, is greatly reduced. Throughput time is reduced by providing the control circuitry for distinguishing between black only and color operation and selectively controlling the printer mode of operation. The hybrid architecture is particularly useful in a LAN system since it provides a mechanism for balancing the relative color versus black page decomposition speed limitations. Also, the hybrid architecture enables a relatively simple implementation of a checkerboarding technique to suppress banding in output prints.
摘要:
A thermal ink jet printer including a frame, a printhead mounted to the frame for printing ink images onto a heated and supported substrate, and an efficient substrate heating and supporting assembly mounted to the frame. The efficient substrate heating and supporting assembly includes a heating device, and a substrate supporting member having a front surface including a substrate supporting area for supporting substrates of various sizes one at a time and border areas having a polished finish. The efficient substrate heating and supporting assembly also includes a heat absorbing back surface facing the heating device. The heat absorbing back surface includes an increased heat absorbing area located opposite and centered relative to the substrate supporting area on the front surface. The increased heat absorbing area, relative to a rest of the back surface, has a coat of paint thereon for increasing heat absorption thereinto from the heating device, thereby resulting advantageously in relatively nonuniform heat absorption into the back surface, and relatively in more uniform, adequate and efficient substrate heating and drying temperatures on the front surface, when continuously running a most often run size of substrates.
摘要:
Modular partial bars include a substrate bar having a length and a plurality of printhead subunits attached to only one side of the substrate bar, each printhead subunit being spaced from an adjacent printhead subunit. These modular partial bars are used as building blocks to form full width staggered array printheads. When the printhead subunits are arranged on each substrate bar so that two substrate bars are capable of forming a full width staggered array printhead, each modular partial bar is referred to as a modular half bar. One modular half bar can be stacked on another modular half bar any number of ways. For example, two half bars can be stacked with their printhead subunit containing sides facing the same direction, away from one another or towards one another. When two half bars are stacked with their printhead subunit containing sides facing in the same direction, an ink manifold for supplying ink to the printhead subunits of the lower half bar can be provided in the substrate of the upper half bar. When half bars are arranged with their printhead subunit containing sides facing each other, a common ink supply manifold can be used to supply ink to all of the printhead subunits in the full width staggered array, thus eliminating the need for two separate ink supply manifolds. By modifying the construction of the channel plates typically used to form the printhead subunits, the need for a separate ink supply manifold can be entirely eliminated.
摘要:
A method and apparatus for drying liquid ink deposited, in response to image data, on a recording medium moving along a path at a predetermined rate. A recording medium having liquid ink deposited thereon is moved past a dryer in multiple passes to dry areas of high ink coverage. Ink characteristics are optimized for minimum print defects by determining the time between printing and drying. In the case of text only images only one pass through the dryer is required. For areas of high ink coverage, however, multiple passes through the dryer are required and completed either by reciprocation or recirculation at the same predetermined rate.
摘要:
A method and apparatus for controlling the volume of ink droplets ejected from thermal ink jet printheads is disclosed. The electrical signals applied to heating elements for generating droplet ejecting bubbles thereon are composed of packets of electrical pulses. Each pulse and spacing therebetween are varied in accordance with one or more whole, clock or timing units. The number of pulses per packet and width of pulses and spacing therebetween are controlled in accordance with the manufacturing tolerance variations, the location of the addressed heating element in the printhead, the number of parallel heating elements concurrently energized, and optionally the temperature of the printhead in the vicinity of the heating elements to maintain the desired volume of the ejected droplets.
摘要:
A multi-pass printbar for providing full width printing on a recording medium is provided. The full width printing may be achieved by stepping the printbar in increments corresponding to the combination of the array width of a printhead die and the gap spacing between the printhead dies until full width print coverage on the recording medium occurs. Ink is ejected from an array of orifices on the printbar as the recording medium passes under the printbar. Alternatively, the full width printing may be achieved by fixing the printbar, and its array of orifices, but stepping the document handler, for example a recirculating drum document handler, the recording medium is mounted upon as it passes under the fixed printbar. Yet another alternative provides full width printing by providing a combination of motions of the printbar and a recirculating drum document handler simultaneously such that the printbar moves continuously and at a constant rate in a linear fashion while the recirculating drum document handler rotates the recording medium under the linearly moving printbar. The result is a “barber pole” style placement of printing information ink droplets on the recording medium which occurs repeatedly due to the rotational recirculation of the recording medium on the drum under the linearly moving printbar until full width print coverage is achieved.
摘要:
A method for controlling a maintenance unit in a printer includes determining an image type of an image to be printed, the image type being selected from at least a first image type and a second image type different from the first image type, setting a maintenance interval for the maintenance unit in accordance with the image type, wherein a maintenance interval for the first image type is different from a maintenance interval for the second image type. A printer embodying such a method, and in particular a printer for printing an image an a substrate, includes a printhead, a maintenance unit for performing periodic maintenance on the printhead, and a controller for controlling said maintenance unit according to the described method.
摘要:
An electrohydrodynamic stimulated ink jet printing device and method of manufacture which eliminates the prior art problem of ink wetting the dielectric spacer between the stimulating electrode and the ink jet nozzles. The nozzles are electroformed on one side of a sheet of dielectric material and the EHD electrodes are electroformed on the other side of the dielectric material in registration with the nozzles. The dielectric material is removed from the nozzles by using the nozzles or the electrodes as masks. The internal surface of the dielectric material is coated with a one of a number of coatings non-wettable by the ink such as a mixture of paraffin and ethylene vinyl acetate copolymer dissolved in a light aliphatic hydrocarbon, such as VMP naphtha.