US2871819A - Xerographic registration guide - Google Patents

Description

Feb. 3, 1959 R. w. GUNDLACH XEROGRAPHIC REGISTRATION GUIDE 2 Sheets-Sheet 1 Filed Aug. 29, 1955 Fi.B

INVENTOR. ROBERT W. GUNDLACH FMASHM ATTORNEY Feb. 3, 1959 w, GUNDLACH 2,871,819

XEROGRAPHIC REGISTRATION GUIDE Filed Aug. 29, 1955 2 Sheets-Sheet 2 4*. V q J 5 INVENTOR.

ROBERT W. GUNDLACH ATTORNEY XERUGRAPHIC REGISTRATION GUIDE Robert W. Gunillach, Spencerport, N. Y., assignor to Haloid Xerox Inc., Rochester, N. Y., a corporation of New York Application August 29, 1955, Serial No. 531,052 6 Claims. (Cl. 118-637) This invention relates to the field of xerography and, particularly, to improvements in apparatus for obtaining accurate registration of a xerographic powder image with the support material to which it is to be transferred.

in a general application of the process of xerography, as disclosed in Carlson Patent 2,297,691, issued October 6, 1942, a. xerographic plate comprising a coating of photoconductive insulating material on a conductive backing is given a uniform electric charge over its surface and is then exposed to the subject matter to be reproduced, usually by conventional photographic techniques such as by camera, projection, or contact exposure, depending upon the type of application. This exposure discharges the plate areas in accordance with the light intensity which reaches them, thereby creating an electrostatic latent image on or in the plate coating. Development is effected with a finely divided material, such as an electroscopic powder, which is brought into contact with the coating and is held thereon electrostatically in a pattern correspondiug to the electrostatic latent image. Finally, the powder image is transferred to a suitable base, such as paper, and. is fixed thereon by fusion or by use of a solvent, in accordance with the type of developing material employed.

In the practice of the art of xerography, as in any graphic arts process, the registration of the copy to be reproduced with the support material on which it is to appear is of prime importance from the standpoint of appearance, convenience of viewing, and, in certain instances, to permit the subsequent addition of variable information on a standard form. In automatic xerographic machines, accurate registration is obtained in a variety of ways that are comparable to those employed in conventional printing processes. However, in manual xerographic processes, accurate registration is largely dependent upon the skill of the operator. In practice, the most critical registration problem arises at the time of transfer of the xerographic powder image from the xerographic plate to its ultimate support material. At this point, the powder image is held on the xerographic plate merely by electrostatic attraction and, thus, is subject to being smeared if contacted by any external substance. Furthermore, the photoconductive surface of the conventional xerographic plate is rela tively soft and can readily be marred or scratched by the use of mechanical registration guides. Finally, because of the sensitive surface of the photoconductive plate, it is not convenient to form a grid structure thereon to assist an operator in aligning the support material therewith. As a result, the operator is obliged to align the support material with the powder image by eye in most instances. In order to avoid smearing the xerographic powder image or damaging the photoconductive surface of the plate, an operator is required to attain a high degree of skill to effect the proper performance of his duties.

The principal object of the present invention is to provide an improved registration guide for use in xerographic processes. A further object is to provide a hired States Patent xerographic registration guide to minimize the possibility of smearing xerographic powder images during transfer operations. A further object is to provide a xerographic registration guide of a construction to minimize the possibility of damage to the photoconductive surface of the xerographic plate during use. A further object is to provide a xerographic registration guide to obtain accurate alignment of a Xerographic powder image formed on a xerographic plate with the support material to which I the powder image is to be transferred.

These and other objects of the invention are attained by means of a registration guide for positioning flexible image support material with reference to a xerographic powder image formed on a xerographic plate assembly wherein the plate assembly comprises a conductive plate member supported in a rectangular frame member, said plate member being provided with a photoconductive coating on the central area thereof and which may have an uncoated marginal area separating the coated area from the frame member, said registration guide comprising a pair of longitudinal base members spaced substantially to abut the inner longitudinal edges of the frame member, each base member being of a lesser width than the marginal area separating the coated area of the plate member from the inner edges of the frame member, a longitudinal guide member for support material mounted on the upper surface of the platform member and a lateral guide member for support material mounted on the upper surface of the platform member normal to the longitudinal guide member. Briefly, the registration guide of the invention comprises substantially parallel base members that are spaced to fit Within the side walls of a conventional xerographic plate and serve to support a support material positioning platform above and out of contact with the xerographic powder image formed on the xerographic plate, said platform being provided with a longitudinal positioning guide for the support material and a lateral support material positioning guide normal thereto.

A preferred form of the invention is disclosed in the appended drawings, in which:

Fig. 1 is an isometric view of a xerographic processing machine with which the invention may be used;

Fig. 2 is an isometric view of a xerographic camera;

Fig. 3 is an isometric view of the registration guide of the invention;

Figs. 4 and 5 are isometric views illustrating operational steps in the use of the xerographic registration guide of the invention in. the transfer of a xerographic powder image to a support material.

Before considering the specific details of the xerographic registration guide of the present invention, it is preferred briefly to summarize the xerographic processing equipment with which such guide is intended for use. A conventional form of xerographic plate assembly currently in wide commercial use is disclosed in Mayo Patent 2,619,418, issued November 25, 1952. A device of this type usually comprises a xerographic plate that is secured in a rectangular plate holding frame having longitudinal side members 42 (see Figs. 4 and 5) and lateral side members 44 that are provided with suitable recessed grooves to accommodate a dark slide to shield the plate from light during its normal use and to protect the surface of the plate from damage when the plate assembly is stored. graphic plate may be formed of various compositions and in various sizes, the type most commonly used at present comprises a conductive metallic backing plate 46 having a surface coating of photoconductive material 48 wherein the exposed surface of the backing plate constitutes an area that is approximately 10%" wide by 15% long, and the photoconductive coating Fatented Feb. 3, 1959- Although the xero- 1; formed thereon covers the entire central area of the platewith the exception ofan uncoated marginal area 50 adjacent the inner edges of the rectangular frame member. The marginal area is usually on the order of %"in width and extends completely around the photoconductive area, thereby leaving a usable photoconductive area of approximately 9 x 14'. it is to be understood that the above-mentioned dimensions are purely illustrative of a conventional type of apparatus and-are not to be considered in a limiting sense in connection with the present invention since is apparent that such plate assemblies may be made in any desired size and may or may not'be provided with the uncoated marginal area, as desired.

In conventional xerographic practice, the charging, developing, and transferring operations are usually carried out: in a xerographic processing device of the type shown in Fig. 1 which illustrates a XeroX Processor Model D manufactured by The Haloid Company, of Rochester, New York; This device is an adaptation of that disclosed in Sahel et al. Patent 2,600,580, issued June 17, 1952, and includes a charging and image transferring unit 1, a developing unit 2, and a storage unit 3. The charging and transferring unit includes a support for a Xerographic'plate assembly onto which the xerographic plate assembly may be inserted through a slot 4. A corona discharge device is mounted within the unit for applying electrostatic charge to the surface of the plate assembly. The charging device is usually in the form of a discharge electrode extending laterally across the machine and is mounted for longitudinal movement over the face of the plate by a suitable lead screw and cross head mechanism. The discharge electrode may be energized by means of a three position switch 5 to apply either positive or negative corona to the surface of the plate. Automatic control of the charging mechanism may be had by means of a switch 6 which concomitantly energizes the electrode and initiates the operation of the lead screw and crosshead mechanism to cause the electrode to traverse the entire surface of a plate assembly that has been inserted in slot 4. The developing unit of the processor may include one or two trays 8 each containing an electroscopic powder or developing agent, depending on the type of development that is to be effected. Each developing tray is mounted on extensible brackets whereby the tray may be pulled forwardly to a position in which it can be rotated about suitable pivots without interference with the remainder of the machine. When so positioned an exposed xerographic plate assembly may be clamped to the developing tray and developed by cascade, in conventional manner. The storage unit of the processor includes an upper storage bin for holding xerographic plate assemblies. The plate assemblies are inserted into the bin through an upper slot 9, and may be withdrawn from the bin through a slot 14 The lower portion of the storage area includes a storage bin for paper or other support material to which the xerographic powder image may be transferred. The support material is withdrawn from the bin through a slot 11 when urged forwardly by a suitable impeller actuated by a handle 12. A hinged cover 13 is provided to enclose the charging and developing units when the apparatus is not in use.

In order to form an electrostatic latent image of a subject to be reproduced on the photoconductive layer of a xerographic plate assembly, the plate assembly is exposed in a camera which may be of the type illustrated in Fig. 2, namely a XeroX Camera No. 4, manufactured by The Haloid Company, of Rochester, New York. Essentially, such a camera comprises a base frame 15, a copyboard 16, mounted at one end thereof, and a camera generally designated by reference character 17. The camera assembly comprises the conventional lens mount 18, extensible bellows 1%, and plate supporting frame for supporting a ground glass focusingscreen or a xerographic plate assembly in the focal plane of the camera. Thecamera elements may be variously positioned on the base frame by means of adjusting screws 21 and 22 to effect any desired enlargement or reduction of the copy to be reproduced. Suitable lights 24 are arranged on the frame assembly for illuminating the copyboard under control of a timing switch 25.

In order to obtain accurate registration of subject material on the xerographic plate assembly, the camera is adjusted at installation so that grid markings 26 that are formed on the copyboard are made to coincide with similar markings formed on the ground glass focusing screen. When the proper adjustments are established, any subject material that is centered on the copyboard with reference to grid markings 26 will have its image projected to be similarly centered on the xerographic plate assembly when a plate is exposed. Rotational registration of support member 2% with reference to grid markings 26 may be eifected by means of levelling screws 27.

In the conventional operation of the above described equipment for the preparation of xerocopies, a xerographic plate assembly is inserted in slot 4 of the charging unit, the dark slide of the plate assembly is removed, and switch 6 is operated to cause a uniform electrostatic charge to be deposited upon the photoconductive surface of the plate assembly. After charging, the dark slide is reinserted in the plate assembly and the entire plate assembly is inserted in plate holding mount 20 of the camera. Then, assuming that the camera has been properly focused with reference to subject material placed on the copyboard, a timed exposure is made to effect the discharge of the electrostatic charges formed on the exposed area of the xerographic plate. After the exposure is complete, the dark slide is replaced in the xerographic plate assembly and the entire plate assembly is removed from the camera and is placed face down in juxtaposition to one of the developing trays in the processing unit. The dark slide is again removed from the plate assembly and the plate assembly is clamped to the developing tray and developed by cascading the developing agent in the tray over the surface of the plate. By this action, the powder particles of the developing agent are electrostatically attracted to the image portions of the electrostatic latent image previously formed on the photoconductive surface of the xerographic plate assembly so that, when development is complete, a reverse reading powder particle image or xerographic powder image of the subject material is formed on such photoconductive surface.

At this point in the conventional process, the operator is obliged to position a piece of paper or other support material over the xerographic powder image on the photo conductive surface of the plate assembly and then, electrostatically transfer the powder image to the surface of the paper. Normally, this is accomplished by manually aligning the paper or support material with the xerographic powder image and superposing the paper thereon. Thereafter, the xerographic plate assembly with the support material superposed on the powder image thereon, is again inserted into slot 4 of the processing unit. This may be effected in conjunction with a concomitant operation of switch 5 whereby the support material is electrostatically charged as it passes beneath the corona charging device to attract the xerographic powder image from the surface of the plate and cause it to adhere to the under surface of the support material. Alternatively, the xerographic plate assembly with the support material superposed thereon may be inserted completely in slot 4 and switch 6 may then be actuated to effect an automatic application of charge to the support material. In either case, the powder image is thereupon electrostatically bonded to the support material and adheres thereto while the support material is-separated from the plate assembly. If desired, the xerographic powder image may subsequently be fused to the support material by any suitable means whereby a permanent visible reproduction of the subject material is formed on the support material.

In order to assist the operator in the application and registration of the support material to the xerographic plate during the transfer operation, the present invention provides a registration guide which is shown in its preferred form in Fig. 3. Essentially, this guide includes a pair of flat elongated strips or base members 31 arranged substantially parallel to each other and spaced apart a distance such that the outer parallel edges of the strips is substantially equal to but slightly less than the distance between the interior of the longitudinal side members 42 of the xerographic plate assembly with which it is to be used. Fixed to the upper surfaces of base members 31 is a platform member 32, having its sides flush with the outer edges of the base members. Preferably, the platform member 32'has a tapered forward portion 33 that unites with a corresponding taper on the forward ends of base members 34 to form a continuous downwardly sloping surface. Fixed on the upper surface of platform member 32 is a guide member 35, of substantially rectangular cross section, that is arranged parallel to the rearward edge of the platform. Fixed to the tapered surface 33 of the platform member is a second guide member 36 that is arranged normal to guide member 35. In the particular embodiment shown, base members 31 are of a width less than that of the marginal area 50 surrounding the photoconductive area of a xerographic plate. If desired, guide member 35 may be provided with an undercut portion 37 that serves as a fingerhold for an operator in manipulating the registration guide.

When employed during the transfer step of a Xerocopying process, the registration guide is positioned as illustrated in Fig. 4, wherein it is positioned between the longitudinal frame members 42 of the plate assembly and is pulled rearwardly so that the rearward edges of base members 31 and platform 32 abut the inner face of the lateral frame member 44 of the plate assembly. As thus positioned, base members 31 hold platform 32 above and out of contact with the xerographic image formed on the plate and, at the same time, provides an ample platform to permit the operator to manipulate the sheet of paper or other support material on which the xerocopy is to be made. The operator does this by pulling the rearward edge of the paper against guide member 35 and, while retaining this relationship, slides one edge of the paper into contact with guide member 36. The guide members 35 and 36 are so positioned on platform 32 that the sheet of support material normally used in this operation is substantially centered with reference to the xerographic plate and the powder image formed thereon. When a paper or support material is thus positioned, the operator allows the remainder of the paper to fall forwardly on the xerographic image. The operator then retains the several elements in position and, with the same hand, slides the plate assembly into the charging unit of the processor until the leading edge of the support material is positioned beneath the discharge electrode. At the same time he actuates switch 5 of the charging unit to apply positive charge to the leading edge of the support material. By this means the support material is electrostatically bonded to the xerographic plate so that the registration guide may be withdrawn from the plate assembly, as illustrated in Fig. 5. Thereafter, the transfer operation is completed in conventional manner, i. e., the operator slides the plate assembly into the charging unit and applies an electrostatic charge over the entire surface of the support material to bond the powder image thereto, then removes the plate assembly from the charging unit and separates the support material from the surface of the plate.

By means of the arrangement thus described, there is provided a xerographic registration guide whereby paper or other support material may be arranged in accurate registration with reference to xerographic powder image formed on a xerographic plate assembly. In the arrangement shown, the base members contact only the uncoated or unused areas of the xerographic plates and thus cannot mar the photoconductive or usuable area of the plate. At the same time the guide assembly is maintained out of contact with the xerographic powder image whereby the possibility of smearing the powder image is minimized.

Obvious modifications could be made in the above describedinvention without departing from the scope thereof. For example, the guide members 35 and 36 may readilybe made adjustable with reference to plat form member 32 to accommodate different size sheets of support material. By way of example, members 35 and 36 may be provided with tenons that are slidable in grooves formed in the surface of platform 32, or members 35 and 36, either individually or as a unit, may be provided with pins that coact with any desired set of combinations of holes variously positioned in the surface of platform 32. In either case, suitable indicia may be placed on the surface of platform member 32 to facilitate positioning of the guide members. Additionally, the width of base members 31 may be varied at will to contact a substantially smaller area of the plate surface in the event the invention is employed in conjunction with xerographic plates having a photoconductive layer over their entire exposed surface, or, since platform 32 is essentially a bridging member that is intended to rest on nonsensitive areas of the plate assembly, the side and rearward edges of the platform may be extended slightly and rabbeted on their undersides so that the platform may be supported entirely by the side and rear rails of the plate assembly. Since many other changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained herein shall be interpreted in an illustrative sense, and that the invention shall be limited only as defined in the appended claims.

What is claimed is:

l. The combination of a xerographic plate assembly and a registration guide detachably positionable thereon for positioning image support material with reference to a powder image formed on the xerographic plate assembly wherein the plate assembly comprises a conductive plate member having a photoconductive coating and being supported in a rectangular frame member, said registration guide comprising a pair of longitudinal base members spaced substantially to abut the inner longitudinal edges of the frame member, a lateral platform member extend- -ing between and supported on said base members, a longitudinal guide member for support material mounted on the upper surface of the platform member, and a lateral guide member for support material mounted on the upper surface of the platform member normal to the longitudinal guide member.

2. The combination of a xerographic plate assembly and a registration guide detachably positionable thereon for positioning image support material with reference to a powder image formed on the xerographic plate assembly wherein the plate assembly comprises a conductive plate member supported in a rectangular frame member, said plate being rovided with a photoconductive coating on the central area thereof and an uncoated marginal area separating the coated area from the frame member, said registration guide comprising a pair of longitudinal base members spaced substantially to abut the inner longitudinal edges of the frame member, each base member being of a lesser width than the marginal area separating the coated area of the plate member from the inner edges of the frame member, a lateral platform member extending between and supported on said base members, said platform member and said base members having downwardly tapered forward portions that conjoin to form a substantially plane surface, a longitudinal guide P? member for supportmaterial mounted on the'upper surface of theplatform member, and a lateral guide member for support material mounted 0I1th upper surface of the platform member normal to the longitudinal guide member.

3. The combination of a xerographic plate assembly and a registration guide detachably positionable thereon for positioning flexible image support material with reference to a powder image formed on the Xerographic plate graphic platemember supported in recessed position in a rectangular frame assembly'having longitudinal and lateral side members, said registration guide comprising a platform member for superposition on said plate assembly, longitudinal and lateral'members' for guiding support material positioned on said platform, said guide members being parallelrespectively with the lateral and longitudinal side members of the plate assembly when the platform member is superposed thereon, and means positionable by the frame assembly side members for supporting the platform member on said plate assembly in spaced relation to the surface of the plate member.

4. The combination of a Xerographic plate assembly and a registration guide detachably positionable thereon for positioning flexible image support material with reference to a powder image formed on the xerographic plate assembly wherein the plate assembly comprises a Xerographic plate member supported in recessed position in a rectangular frame assembly having longitudinal and lateral side members, said registration guide comprising a substantially rectangular platform member for superposition on said plate assembly, said platform member having a lateral dimension substantially to abut the longitudinal side members of the frame assembly, longitudinal and lateral guide members mounted on said platform for positioning support material, said guide members being parallel respectively with the lateral and longitudinal side members of the plate assembly when the platform member is superposed thereon, and means for supporting the platform member on said plate assembly in l spaced relation to the surface of the plate member.

5. The combination of a Xerographic plate assembly and a registration guide detachably positionable thereon for positioning flexible image support material with reference to a powder image formed on the Xerographic plate bly, longitudinal and lateral guide members mounted on "assembly wherein the plate assembly comprises a xero- I3 said platform for positioning support material, said guide members being parallelrespectively with the lateral and longitudinal 'side members of the plate assembly when theplatform member is superposed thereon, means positionable by the frame assemblyside members for supporting the platform member on said plate assembly in spaced'relation to the surface of the plate member, and a plane surface on the platform member inclined toward the surface of the plate member when the platform member is superposed on the plate assembly.

6. in combination with a Xerogra'phic plate assembly including a rectangular frame assembly having longitudinal and lateral side members, a conductive plate member supported therein, said plate member being provided with a photoconductive coating on the central area thereof and an uncoated marginal area separating the coated area from the side members of said frame assembly, a registration guide, detachably positioned on said plate assembly, comprising a pair of longitudinal base members spaced substantially to abut the inner edges of the longitudinal side members of said frame assembly, each base member being of a lesser width than the marginal area separating the coated area of the plate member from the inner edges of the side members of said frame assembly, a lateral platform member extending between and supported on said base members, and longitudinal and lateral guide members mounted on the upper surface of said platform for positioning support material, said guide members being parallel respectively with the longitudinal and lateral side'members of said frame assembly.

References Cited in the file of this patent UNITED STATES PATENTS 10,432 Disston May 24, 1870 662,982 Stevens Dec. 4, 1900 910,330 Wait Ian. 19, 1909 1,001,532 Kenyonet al. Aug. 22, 1911 1,430,911 Linebaugh Oct. 3, 1922 1,506,990 Multaler Sept. 2, 1924 2,392,031 Denyven et al. Jan. 1, 1946 2,619,418 Mayo Nov. 25, 1952 2,620,184 Paley Dec. 2, 1952 2,689,179 Walkup et al. Sept. 14, 1954 2,729,195 Belz Jan. 3, 1956 2,741,222 Shelton Apr. 10, 1956 2,771,027 Ritzerfeld et al. Nov. 20, 1956 2,807,232 Hudson Sept. 24, 1957 FOREIGN PATENTS 1,062,549 France Apr. 23, 1954

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