Presstek, Inc.

Other

Presst, Inc.

John F Kline

Richard A Williams

Thomas E Lewis

Frank G Pensavecchia

Michael T Nowak

John P Gardiner

Bradley W Davidson

Kenneth T Robichaud

Stephen M LaPonsey

Keith V Robb

John Gary Sousa

Glenn E Cabana

Wayne Mueller

Lawrence A Howard

Apparatus and methods for imaging lithographic plates using laser devices that emit in the near-infrared region, and plates suitable for imaging with the apparatus and methods. Laser output either ablates one or more plate layers or physically transforms a surface layer, in either case resulting in an imagewise pattern of features on the plate. The image features exhibit an affinity for ink and/or a fluid to which ink will not adhere that differs from that of unexposed areas.

Laser-driven method and apparatus for lithographic imaging and printing

Compensation for the effects of duty cycle on the output level of an imaging device, and for the effects of periodically varying distance between the output of the imaging device and its target, is accomplished electronically. An exemplary apparatus includes a source of radiation (generally a laser) having an output level that varies both with an input power level and, undesirably, with the duty cycle. The radiation source is operated to produce, on the recording surface, an imagewise pattern of spots, and an adjustment facility compensates for output-level variations resulting from duty cycle--that is, from the recent pattern of laser activity.

Method and apparatus for diode-laser imaging with compensation for

Apparatus and methods for imaging lithographic plates using laser devices that emit in the near-infrared region, and plates suitable for imaging with the apparatus and methods. Laser output either ablates one or more plate layers or physically transforms a surface layer, in either case resulting in an imagewise pattern of features on the plate. The image features exhibit an affinity for ink or an ink-abhesive fluid that differs from that of unexposed areas.

Laser-imageable lithographic printing members

In a digital imaging system including an array of imaging devices that apply an image to a recording medium such as a lithographic printing plate, elimination or reduction of longitudinal imaging artifacts is accomplished by blending the zones imaged by each the devices. In the course of a complete scan of the recording medium, the imaging devices each traverse a series of longitudinal columns of dot locations, and the devices are fired only at appropriate dot locations as determined by the digital image data. By operating adjacent imaging devices such that the zones they would ordinarily cover are blended, artifacts at the boundary between zones (such as seams) are hidden. While sufficient visual disruption to eliminate artifacts is ensured, noticeable visual artifacts are not created as a consequence of the disruption.

Method and apparatus for digital imaging with reduced periodic artifacts

A plate imaging apparatus and method for imaging a seamless printing member preferably loaded onto a rotating plate cylinder. The plate imaging apparatus moves a writing head in fixed increments in an axial direction relative to the plate cylinder. With the writing head fixed at a first axial position, the imaging apparatus causes a circumferential swath to be imaged onto the seamless printing member commencing from a first starting point. With the plate cylinder still rotating, the imaging apparatus then steps the writing head to the next axial position, thereby defining a second starting point once the writing head is ready to resume imaging that is offset from the first starting point. The imaging apparatus then causes a second circumferential swath to be imaged onto the seamless printing member commencing from the second starting point.

Method and apparatus for imaging a seamless print medium

Laser guiding and focusing apparatus for imaging lithographic printing members responsive to the output of laser devices. Radiation passes through at least one discrete layer of a printing member and ablates one or more underlying layers, resulting in an imagewise pattern of features on the printing member. The radiation is obtained from a laser diode and its dispersion reduced to produce an image spot with maximum depth-of-focus tolerance.

Apparatus for laser-discharge imaging including beam-guiding assemblies

Lithographic printing plates for use with laser discharge imaging

In a digital imaging system including an array of imaging devices that image a substrate in a lateral series of adjacent longitudinal swaths, methods and apparatus for correcting device offset and hiding between regions imaged by adjacent devices. Along the direction of imaging (i.e., the dimension along which the imaging device(s) and the substrate move relative to one another during an imaging pass), adjustments take the form of compensating increases or decreases to the normal intervals between discharges to adjacent image points. Transverse to the direction of imaging, the invention compensates for imprecise device orientation and 'seam' artifacts by, first, commencing imaging with the device having the greatest offset from proper orientation, and second, as a fine adjustment, repeating at least one imaging swath to produce intentional transverse overlap between adjacent swaths.

Method and apparatus for correcting and adjusting digital image output

Laser-driven method and apparatus for lithographic imaging

Techniques for imaging lithographic printing members responsive to the output of laser devices. Laser output passes through at least one discrete layer and ablates one or more underlying layers, resulting in an imagewise pattern of features on the printing member. The image features exhibit an affinity for ink or an ink-abhesive fluid that differs from that of unexposed areas.

Method for laser-discharge imaging a printing plate

A method of and apparatus for imaging a lithographic plate having a printing surface by exposing the printing surface to plasma jet discharges between the plate and a plasma jet nozzle spaced close to the printing surface of the plate. These plasma jet discharges are sufficient to ablate or otherwise transform one or more layers of the printing surface, thereby changing the affinity of the printing surface for ink and/or water at the points thereof exposed to the discharges so as to produce image spots on the plate.

Plasma-jet imaging apparatus and method

Electrode-driver circuits for use with non-contact spark-discharge imaging systems. The circuits rapidly produce short-duration, high-voltage pulses that cause the discharge of a spark to the surface of a printing plate; they feature short rise times, rapid operation and clean decays, thereby facilitating high-speed spark-discharge imaging.

Drive circuits for spark-discharge imaging apparatus

Apparatus and method for imaging a lithographic plate having an oleophobic first layer, a metal second layer and an oleophilic third layer. The first and second layers are removed in an imagewise pattern to reveal the third layer, resulting in direct production of image spots. The plate is ready for printing at the conclusion of the imaging process.

Growing community of inventors

Londonderry, NH, United States of America

John F Kline