US 3272066 A
Description (OCR text may contain errors)
Sept. 13, 1966 R. E. RICE 3,272,066
COPYING APPARATUS Filed March 8, 1963 W W, m @211 INVENTOR.
zzmam f Ewe United States Patent 3,272,066 COPYING APPARATUS Richard E. Rice, Arlington, Mass., assignor to Corrrstock & Wescott, Inc., Cambridge, Mass., a corporation 0 Massachusetts Filed Mar. 8, 1963, Ser. No. 263,939 Claims. (Cl. 88-24) This invention relates to apparatus for reproducing a record and particularly to apparatus for forming an electrostatic image on photoconductive paper or the like by projection printing such as described and claimed in the copending application of Kenneth J. White, Ser. No. 337,477, which is a continuation-in-part of Ser. No. 263; 804, filed on even date herewith and now abandoned.
Objects of the invention are to provide copying apparatus which is simple and economical to produce, which is compact, which reproduces a record uniformly throughout its entire area, which corrects for lenses having deficient coverage, and which is quickly and easily adjustable.
This inverition involves a printer comprising a chamber having a record window to receive a record sheet, and a print window to receive a sheet of photographic material, with a lens between the two windows to focus the record sheet on the photographic sheet, the chamber and windows having corresponding rectangular shapes, in combination with means for illuminating the record sheet including a light source in each of the four corners of the chamber opposite the record window, the sides of the chamber being reflective, and a reflector behind each light source to direct light to the aforesaid sides. Preferably the reflectors direct the light predominantly to the corners of the record sheet, thereby to illuminate the corners more than the central portion of the record sheet, and a baffle is mounted in front of each light source to prevent light from being reflected directly from the record window to the lens. By illuminating the corners more than the central portion of the record sheet the distance from the record sheet to the lens may be greatly reduced without causing the density of the print to fall 01f rapidly from the center outwardly. Thus the apparatus may be made much more compact, which is especially important for electrostatic printers used in offices and other places Where space'is at a premium.
For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawing in which FIG. 1 is a vertical section of the apparatus;
FIG. 2 is a section on line 22 of FIG. 1; and FIG. 3 is an enlarged side view of one of the lamp assemblies.
The particular embodiment of the invention chosen for the purpose of illustration comprises a casing having two chambers 1 and 2 with a partition 3 therebetween. In the top of chamber 1 is a record window 4 covered by a transparent plate 5 and a cover 6, and at the side of the chamber 2 is a print window 7 behind which a strip 8 of photoconductive material may be fed over rollers 9 and 11 as described in the aforesaid application. Mounted in the partition 3 is a projection lens 12 for projecting a record in window 4 to the print window 7, the projected light being reflected by a mirror 13.
According to this invention lamps 14, 15, 16 and 17 are mounted on brackets 18 in each of the four corners of the chamber 1 opposite the record Window 4. Each of these lamps is preferably of the well-known projection type, having a concentrated filament 19 and a built-in reflector 2.1 for reflecting light away from the corner in which the lamp is mounted. In front of each lamp is a baffle 22 for preventing light from being reflected directly from the transparent plate 5 to the lens without being reflected from one of the side walls 23, 24, 25 and 26 of chamber 1 which are made reflective in any suitable way. The reflectors should be specular, that is, mirrorlike surfaces, and not diffuse reflectors like painted surfaces. If shiny aluminum foil is used it should be stretched to lie flat. As shown in FIG. 1 the axes of the beam from each lamp is directed approximately parallel with the adjacent side wall, the axes of lamps 14 and 17 extending along wall 26 and the axes of lamps 15 and 16 extending along wall 24. Thus the axes of the beams from lamps 14 and intersect wall 25 and the axes of the beams from lamps 16 and 17 intersect the wall 23. Owing to divergence each beam spreads over a considerable surface of the reflective sides so that the illumination of the record window is approximately uniform. For example, light from lamp 15 is reflected strongly from walls 24 and 25, less strongly from wall 26 and not at all from wall 23. By aiming the beams toward the corners of chamber 1 as aforesaid, the corners of the record window may be illuminated somewhat more than the central portion, the illumination gradually decreasing toward the center, thereby to compensate for usual lens deficiencies.
As shown in FIG. 3 the battles 22 may be adjustably mounted on supports 27 which are hinged at 28 to swing to the dotted-line position 22 to facilitate adjustment and replacement of the lamps, the supports being held in upright position by spring detents 29. The bafiles are adjusted to prevent specular reflections from entering the print Window, but may allow as much as about twentyfive percent of the light to shine directly on the windows at their corners in order to obtain increased illumination at the corners as aforesaid. Inasmuch as the baflles tend to cast shadows on the window 5 and to get evenness of illumination the edges of the shadows should be diffuse. This may be accomplished by placing the baflles close to the lamps or making the edges of the baflles saw-toothed, as indicated at 30 in FIG. 2, or both.
It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.
1. A printer having a record window to receive a rec ord, a print window to receive a sheet of photographic material, a lens between the two windows to focus the record on said sheet, a chamber enclosing the space between the lens and record window, and light-producing means in said chamber, and reflector lmeans disposed adjacent the light-producing means to reflect light away from said lens and shaped to reflect light from said light-producing means to said record window 'with increasing intensity outwardly from the center of the record window.
2. A printer having a record window to receive a record, a print window to receive a sheet of photographic material, a lens between the two windows to focus the record on said sheet, a chamber enclosing the space between the lens and record window, said chamber and windows having corresponding rectangular shapes and the record window and lens being disposed in opposite sides of the chamber, and means in said chamber for producing illumination on the record which gradually in creases from the center outwardly, said means comprising a light source in each of the four corners of the chamber opposite the record window and a reflector behind each light source to direct light predominantly to the corners of the record.
3. A printer according to claim 2 wherein the sides of said chamber are reflective.
4. A printer having a record window to receive a record, a print window to receive a sheet of photographic 3 4 material, a lens between the two windows to focus the References Cited by the Examiner record on said sheet, a chamber enclosing the space be- UNITED STATES PATENTS tween the lens :and record window, means in said chamber for producing illumination on the record which 'gradgoqdon 88 24 lly increases from the center outwardly and means to 5 .i 2,940,358 6/1960 Rosenthal 88-24 prevent light from being reflected directly from the rec- 3,157,087 11/1964 Kanenberg 88 24 0rd window to the lens.
5. A printer according to claim 4 wherein said last NORTON ANSHERPHmarY Exammermeans comprises bafiies in front of the light sources. R. A. WINTERCORN, Assistant Examiner.