Abstract: A printing system that includes a printhead head containing ink, and a tray cooperatively associated with the printhead and containing a waste solution in which the printhead is immersed to seal the printhead to prevent the ink from clogging the printhead when the printing system is not in operation.

Abstract: A printing system that includes a web guide having a preprinting section which guides a substrate into the printing system, and a postprinting section which maintains tension in the substrate as the substrate moves through the printing system. A printing section is positioned between the preprinting section and the postprinting section. The printing section includes a removable platen to provide a gap in the printing section to prevent excess ink which is deposited onto the substrate from accumulating underneath the substrate.

Abstract: A printing apparatus for printing images on a substrate. The printing apparatus is provided with a first print head connected to a selector valve which in turn is connected to a pair of reservoirs. The first reservoir holds one type of ink while the other reservoir holds a different type of ink. The selector valve has two selectable states. The first state facilitates transmitting ink from one of the reservoirs to the print head, and the second state facilitates transmitting ink from the other reservoir to the print head. The selector valve can be coupled to a controller which is computer operated. Alternatively, the controller can be manually operated.

Abstract: A method of cleaning ink jet printheads without rendering the printheads inoperative by soaking the printheads in a cleaning solution of acetone and n-methyl-2-pyrolidine, and then flushing the printhead with a gas, such as air. The solution is made of about 70% acetone and about 30% n-methyl-2-pyrolidine by weight.

Abstract: A positioning system for a carriage in a printing system includes a support plate having a groove along a length of the plate, and a rail positioned along the groove. A first adjusting mechanism is used to adjust the position of the rail in a first direction, and a second adjusting mechanism is used to adjust the position of the rail in a second direction that is substantially normal to the first direction.

Abstract: A system for printing images on a substrate includes a multiplicity of print heads mounted in a carriage and positioned a distance from the substrate. A sensor detects the thickness of the substrate as the substrate moves through the system, and a control system receives the substrate thickness information detected by the sensor and transmits signals to a motor coupled to the carriage. These signals instruct the motor to adjust the position of the carriage to maintain a desired gap between the print heads and the substrate.

Abstract: A printing apparatus for printing images on a substrate includes a first set of print heads S1 having at least one print head P1,1 arranged to deposit a first ink I1, and a second set of print heads S2 having at least two print heads P2,1, P2,2 arranged to deposit a second ink I2. The at least one print head P1,1 of the first set S1 and a first print head P2,1 of the second set S2 respectively depositing the first ink I1 and the second ink I2 in a first order of deposition O1, and the at least one print head P1,1 of the first set I1 and a second print head P2,2 of the second set S2 respectively depositing the first ink I1 and the second ink I2 in a second order of deposition O2 as the printing apparatus traverses across the substrate in one direction D1. The order of deposition of the first ink I1 and the second ink I2 from the print heads is reversed as the printing apparatus traverses across the substrate in an opposite direction D2.

Abstract: An apparatus for transporting a substrate in a printing system includes a transport belt provided with a plurality of holes which extend through a thickness of the belt, and a vacuum table which generates a vacuum, and is positioned on one side of the transport belt. A porous sheet is positioned between the belt and the vacuum table, while the vacuum table, the porous sheet, and the transport belt are in fluid communication. The vacuum generated by the vacuum table creates a suction on the substrate placed on the transport belt, and the porous sheet restricts fluid flow between the table and the transport belt to maintain a desired vacuum as an area of the transport belt covered by the substrate varies as the substrate is transported through the printing system.

Abstract: A printing system that includes a source which emits UV radiation to polymerize a fluid that is deposited onto a substrate by one or more print heads. The source emits low energy UV radiation sufficient to set the fluid to a quasi-fluid, non-hardened state.

Abstract: A printing system that includes a web guide having a preprinting section which guides a substrate into the printing system, and a postprinting section which maintains tension in the substrate as the substrate moves through the printing system. A printing section is positioned between the preprinting section and the postprinting section. The printing section includes a removable platen to provide a gap in the printing section to prevent excess ink which is deposited onto the substrate from accumulating underneath the substrate.

Abstract: A system for printing images on a substrate includes a multiplicity of print heads mounted in a carriage and positioned a distance from the substrate. A sensor detects the thickness of the substrate as the substrate moves through the system, and a control system receives the substrate thickness information detected by the sensor and transmits signals to a motor coupled to the carriage. These signals instruct the motor to adjust the position of the carriage to maintain a desired gap between the print heads and the substrate.

Abstract: An apparatus for setting radiation curable ink deposited onto a substrate. The apparatus includes a series of ink jet print heads which deposit ink onto the substrate, and a radiation source mounted laterally adjacent to the series of ink jet print heads. The amount of energy provided by the radiation source is sufficient to cause the radiation curable ink to set.

Abstract: Reproducing a predetermined pattern on a medium, by for example, an apparatus that includes in combination a source of colored ink, a primary source of compressed air, a spray head including a housing having an inner ink chamber in flow communication with the source of ink, an outer air chamber in flow communication with the source of air and surrounding the inner ink chamber, a spray nozzle having an outside diameter and an internal longitudinal bore connected to the inner ink chamber and extending forward of the housing. A spray shield has an outer surface adjacent the medium and an inner surface positioned adjacent to and spaced from the housing and has a transverse opening therethrough in alignment with the nozzle. An auxiliary air supply has a pressure significantly less than the pressure of the air from the primary source of compressed air.

Abstract: Reproducing a predetermined pattern on a medium, by for example, an apparatus that includes in combination a source of colored ink, a primary source of compressed air, a spray head including a housing having an inner ink chamber in flow communication with the source of ink, an outer air chamber in flow communication with the source of air and surrounding the inner ink chamber, a spray nozzle having an outside diameter and an internal longitudinal bore connected to the inner ink chamber and extending forward of the housing. A spray shield has an outer surface adjacent the medium and an inner surface positioned adjacent to and spaced from the housing and has a transverse opening therethrough in alignment with the nozzle. An auxiliary air supply has a pressure significantly less than the pressure of the air from the primary source of compressed air.

Abstract: An automatic system for the spray painting of color images in which accurate color reproduction is achieved by a separate look-up table generated for each jet and stored in the computer memory. During the reproduction of an image, the computer uses the look-up tables to determine the pulse width of an air modulation stream to reproduce the precise color density called for by the input data. Because slight variations in the characteristics of two jets spraying the same color would produce objectionable lining in the image, a separate look-up table is provided for each jet. A color test image is generated for a selected jet by successively varying the width of the pulse modulation from the minimum to the maximum. For example, while the jet is making a single scan across the medium, the pulse width modulation of the air stream is varied in 256 separate steps to produce a test image that varies from the lightest to the darkest density of the particular color being sprayed.

Abstract: A printing system for the reproduction of large scale images by spray painting on a wide flexible medium such as vinyl or paper. A movable cradle is provided with a series of spaced endless belts that provide lateral support for the roll of medium to be painted or imprinted. The endless belts are in turn rotatably supported by a frame of sufficient strength to prevent significant bending of the structure. The belts are mounted on low-friction rollers that permit the medium roll to rotate as material is drawn from the roll into the painting system. The direction of material withdrawal is substantially vertical so that the roll remains in its controlled position as the size of the roll becomes smaller and to facilitate printing on either surface of the medium. The cradle is mounted on casters so that it can be readily moved into the frame of the painting system and locked in position.

Abstract: A system for reproducing color images by electronically scanning an original to control the paint-spraying of a larger duplicate image. Multiple ink spray heads scan the width of the recording medium while being controlled by width-modulation of constant air pressure supplied to the heads. Ink is contained in multiple reservoirs that are each connected to one of the spray heads by a conduit extending substantially perpendicular to the direction of travel of the spray heads. Each ink reservoir contains a sub-reservoir with a bottom surface above the level of the bottom surface of the primary reservoir. Sloping deflector plates cause ink to flow from the primary reservoir into the sub-reservoir during acceleration or deceleration of the reservoirs. The height of the ink in the reservoir is such that a meniscus of ink is maintained on the tip of the spray jet during periods when ink is not being sprayed.

Abstract: A system for copying images onto a long sheet of paper or vinyl while. A flow of constant-pressure air is pulse-width modulated in accordance with the control signals and passed over an ink meniscus maintained on the end of a small nozzle. The pulse-modulated air flowing across the meniscus causes the ink to be sprayed onto the recording medium. The dot size on the image remains constant and the pulse width within each pixel is varied to produce the desired density of color. Pressure surges in the ink supply system, produced for example by vibration or acceleration of the ink, are suppressed by a second meniscus in the ink-supply system, formed by a gas bubble or interface near the nozzle meniscus. The second meniscus should have a surface area at least as large as that of the jet meniscus. At the end of each pixel, the ink flow is interrupted for a period of about 100 microseconds to restore system equilibrium.