Incremental printing of symbolic information – Thermal marking apparatus or processes – Recording means engaging or holding means
Reexamination Certificate
2000-08-23
2002-06-04
Barlow, John (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Recording means engaging or holding means
Reexamination Certificate
active
06400387
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a linear translation subsystem of an image-forming apparatus of the lathe bed scanning type for creating an image on sheet media held on a rotating imaging drum, and more particularly to the alignment of the translation bearing rod or rods to the imaging drum surface.
BACKGROUND OF THE INVENTION
Pre-press color proofing is a procedure that is used by the printing industry for creating representative images of printed material without the high cost and time that is required to actually produce printing plates and set up a highspeed, high-volume printing press to produce an example single of an intended image. These intended images may require several corrections and be reproduced several times to satisfy customers requirements, which results in loss of profits. By utilizing pre-press color proofing, time and money can be saved.
One such commercially available image-forming apparatus, which is depicted in commonly assigned U.S. Pat. No. 5,268,708, is an image forming apparatus having half-tone color proofing capabilities. This image forming apparatus is arranged to form an intended image on a sheet of thermal print media by transferring colorant from a sheet of colorant donor material to the thermal print media by applying a sufficient amount of thermal energy to the colorant donor material to form an intended image. This image forming apparatus is comprised generally of a material supply assembly or carousel; lathe bed scanning subsystem, which includes a lathe bed scanning support frame, translation drive, translation stage member, printhead, and imaging drum; and thermal print media and colorant donor material exit transports.
The operation of the image-forming apparatus includes metering a length of the thermal print media (in roll form) from the material assembly or carousel. The thermal print media is then measured and cut into sheet form of the required length and transported to the imaging drum, registered, wrapped around, and secured onto the imaging drum. Next, a length of colorant donor material (in roll form) is also metered out of the material supply assembly or carousel, then measured and cut into sheet form of the required length. It is then transported to and wrapped around the imaging drum, such that it is superposed in the desired registration with respect to the thermal print media (which has already been secured to the imaging drum). A rotatable vacuum imaging drum is preferred herein.
After the colorant donor material is secured to the periphery of the imaging drum, the scanning subsystem or write engine provides the scanning function. This is accomplished by retaining the thermal print media and the colorant donor material on the spinning vacuum imaging drum while it is rotated past the printhead that will expose the thermal print media. The translation drive then traverses the printhead and translation stage member axially along the vacuum imaging drum, in coordinated motion with the rotating vacuum imaging drum. These movements combine to produce the intended image on the thermal print media.
After the intended image has been written on the thermal print media, the colorant donor material is then removed from the vacuum imaging drum. This is done without disturbing the thermal print media that is beneath it. The colorant donor material is then transported out of the image forming apparatus by the colorant donor material exit transport. Additional colorant donor materials are sequentially superposed with the thermal print media on the vacuum imaging drum. Then they are imaged onto the thermal print media as previously mentioned, until the intended image is completed. The completed image on the thermal print media is then unloaded from the vacuum imaging drum and transported to an external holding tray on the image forming apparatus by the receiver sheet material exit transport.
The material supply assembly comprises a carousel assembly mounted for rotation about its horizontal axis on bearings at the upper ends of vertical supports. The carousel comprises a vertical circular plate having in this case six (but not limited to six) material support spindles. These support spindles are arranged to carry one roll of thermal print media, and four rolls of colorant donor material to provide the four primary colors used in the writing process to form the intended image, and one roll as a spare or for a specialty color colorant donor material (if so desired). Each spindle has a feeder assembly to withdraw the thermal print media or colorant donor material from the spindles, which is to be cut into a sheet form. The carousel is rotated about its axis into the desired position, so that the thermal print media or colorant donor material (in roll form) can be withdrawn, measured, and cut into sheet form of the required length, and then transported to the vacuum imaging drum.
The scanning subsystem or write engine of the lathe bed scanning type comprises the mechanism that provides the mechanical actuators, for the vacuum imaging drum positioning and motion control to facilitate placement, loading onto, and removal of the thermal print media and the colorant donor material from the vacuum imaging drum. The scanning subsystem or write engine provides the scanning function by retaining the thermal print media and colorant donor material on the rotating vacuum imaging drum, which generates a once per revolution timing signal to the data path electronics as a clock signal while the translation drive traverses the translation stage member and printhead axially along the vacuum imaging drum in a coordinated motion with the vacuum imaging drum rotating past the printhead. This is done, with positional accuracy maintained, to allow precise control of the placement of each pixel in order to produce the intended image on the thermal print media.
The lathe bed scanning frame provides the structure to support the linear translation subsystem, printhead, and the imaging drum and its rotational drive. The translation stage member and printhead are supported by two translation bearing rods that are ideally straight along their longitudinal axis. This permits low friction movement of the translation stage member and the translation drive. The translation bearing rods are positioned and supported at their ends by bores in the outside walls of the lathe bed scanning support frame or write engine.
The two translation bearing rods are arranged between the translation stage member and the printhead. A front translation bearing rod is arranged to locate the axis of the printhead precisely on the axis of the imaging drum with the axis of the printhead located perpendicular, vertical, and horizontal to the axis of the imaging drum. The translation stage member front bearing is arranged to form an inverted “V” and provides only that constraint to the translation stage member. The translation stage member is held in place by its own weight. The rear translation bearing rod locates the translation stage member with respect to rotation of the translation stage member about the axis of the front translation bearing rod. This is done so that no over constraint of the translation stage member causes it to bind, chatter, or otherwise impart undesirable vibration to the translation drive or printhead during the writing process. Such vibrations can cause unacceptable artifacts in the intended image. The rear bearing enables this advantage by engaging the rear translation bearing rod only on diametrically opposite side of the translation bearing rod on a line perpendicular to a line connecting the centerlines of the front and rear translation bearing rods.
Although currently available image forming apparatus are satisfactory, they do have certain drawbacks. First, alignment of the linear translation subsystem limits the output quality that the intended image can be exposed onto the thermal print media within the intended image, intended image to intended image within a given image forming apparatus, or intended image to intended image, from one image form
Barlow John
Feggins K.
Harleston Law Firm
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