US3920952A

US3920952A - Duplex fusing apparatus and method

Info

Publication number: US3920952A
Application number: US516058A
Authority: US
Inventors: Thomas L Donnelly; Edward J Mullen
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1974-10-18
Filing date: 1974-10-18
Publication date: 1975-11-18
Anticipated expiration: 1992-11-18
Also published as: DE2544637A1; CA1059575A; NL7511622A; JPS5165633A; FR2311339A1; GB1526738A

Abstract

An improved flash fusing apparatus for fusing toner images onto flexible support material. First and second elongated flash lamps are closely spaced and a flexible support web bearing loose toner images on both sides is advanced along a predetermined cylindrical path encircling each of the flash lamps along its longitudinal axis exposing each side of the web to flash radiation from the lamps.

Description

United States Patent [191 Donnelly et al.

1 1 Nov. 18, 1975 [5 DUPLEX FUSING APPARATUS AND METHOD I [75] Inventors: Thomas L. Donnelly; Edward J.

Mullen, both of Webster, NY.

[73] Assignee: Xerox Corporation, Stamford,

Conn.

[22] Filed: Oct. 18, 1974 [21] Appl. No.: 516,058

[52] US. Cl 219/216 [51] Int. Cl. H05B 1/00 [58] Field of Search 219/216, 388;

[56] References Cited UNITED STATES PATENTS Roshon, .lr 219/216 5/1969 Michaels 219/388 X 9/1969 Nakamura et al. 219/216 X Primary Examiner-C. L. Albritton ABSTRACT An improved flash fusing apparatus for fusing toner images onto flexible support material. First and second elongated flash lamps are closely spaced and a flexible support web bearing loose toner images on both sides is advanced along a predetermined cylindrical path encircling each of the flash lamps along its longitudinal axis exposing each side of the web to flash radiation from the lamps.

4 Claims, 1 Drawing Figure us. Patent NOv.18,1975 3,920,952

The invention relates generally to flash fiising and particular to a method and apparatusfor fusingtoner images onto flexible support materials- More ,speci' fi cally, this invention relates'to a xerographicflash fusing apparatus and methods for rapidly and efficiently producing uniform duplex image fixing on each sidesof support material. 1%

In the xerographic 'prooess'jsa plate, generally comprising a conductive backingupon which placed a photoconductive I insulating ysurface, is uniformly charged and the photoconductive surface then exposed to a light image of an original to be reproduced. The photoconductive surface is caused to become conductive under the influence of the light imageso as to selectively dissipate theelectrostatic charge, found thereon to produce what is developedby means of a variety of pigmented resin materials specifically made for this purpose which are known in the xerographic art as toners. The toner material is electrostatically attracted to the latent image areas on the plate proportion to the charge concentration foundthereon fAreas 'tiie flash fusing process, a major problem with flash fusant energy. Because of the properties of most copy materials-as for example, paper, most" of the energy inci-' dent thereon is wastedby being transmitted through the copy or by being reflected-away from the fusing area. Another disadvantage-associated withthe prior art flashfusing apparatus has heretofore been the nonuniformity'of image fixing produced. This phenomena is primarily due to the fact that it is difficult to produce v highly uniform irradiance on a large receiving surface as for example a sheet of pa'per,from a relatively small source such as a flash lamp. This problem is further heightened in the case of duplex images on both sides "While considerable effort has been expended in pro- "s iding s'chemes'forenhancing the efficiency and uniforof high chargev concentration become areas of high toner density while correspondingly low charge image areas become proportionally less dense. The developed image is transferred to a final support material, typically paper, and fixed thereto to form a permanent record or copy of the original.

Many forms of image fixing techniques are known in the prior art, the most prevalent of which are vapor fixing, heat fixing, pressure fixing or a combination thereof as described in US. Pat. No. 3,539,161. Each of these techniques, by itself or in combination suffer,

efficiency, and ease of control. A further problem associated with heat fusers has been their tendency to burn or scorch the support material. Pressure fixing methods, whether hot or cold have created problems with image offsetting, resolution degradation and producing consistently a good class of fix. On the other hand, vapor fixing, which typically employs a toxic solvent has proven commercially unfeasible because of the health hazard involved.' Equipment to sufficiently isolate .the fuser from the surrounding ambient air must by its very nature be complex and costly.

With the advent of new materials and new xerographic processing techniques, it is now feasible to construct automatic xerographic reproducing apparatus capable of producing copy at an extremely rapid rate. Radiant flash fusing is one practical method of image fixing that will lend itself readily to use in a high speed automatic process as described in US. Pat. No. 3,529,129. The main advantage of the flash fuser over the other known methods is that the energy, which is propagated in the form of electromagnetic waves, is instantaneously available and requires no intervening medium for its propagation. As can be seen, such apparatus does not require long warm-up periods nor does the energy have to be transferred through a relatively slow conductive or convective heat transfer mechamsm.

Although an extremely rapid transfer of energy between the source and the receiving body is afforded by mity of fix of electrographic flash fusing systems, most efforts have been-directed toward the provision of specially contoured reflecting surfaces which are designed to at least partially surround the flash lamp and thereby conserve energy via multiple reflections as set forth in US. Pat. No. 3,529,129. In addition to being costly to fabricate, such reflecting surfaces tend to become contaminated by loose toner particles and thereby necessitate frequent cleaning operations.

It is therefore an object of this invention to improve flash fusing of xerographic toner images on support material.

Another object of the invention is to accomplish flash fusing of either simplex or duplex electrostatic images with a single flash for a predetermined area.

Another object of the invention is to enable highly efficient fusing of toner images onto flexible support material.

Still another object of the invention is to fuse loose toner images on both sides of a support material simultaneously.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following description wherein the FIGURE is a side view of a web of support material bearing xerographic toner images on each side thereof for fusing according to the present invention.

Referring now to the Figure in accordance with the present invention, loose image toner particles 10 and 11 deposited onto a flexible support web 12 at

developer stations

14 and 15 respectively, are fused simultaneously. Web 12 is transported about the axes of elongated sources of radiant energy in the form of

flash lamps

16 and 18. The web is advanced along the curved path of a guide track 20 by a driven roller 22 which is rotated in a direction indicated by the arrow. It will be appreciated that images 10 and 11 are moved along a circular path in each fusing zone such that the toner images are untouched and continuously face toward the center of curvature of the path where flash fusing' lamps l6 and 18 are situated. It will be further appreciated that each of the flash fusing lamp fusing zones has a configuration which is circular or cylindrical such that uniform irradiance is insured to all points on the cylindrical surface from the particular flash lamp positioned along the central axis thereof. In this manner, it is not necessary to fuse the images onto a support material in piece meal fashion by energizing the lamp a number ofvery good toner fusion. Pulse durations between 0.25

and 1.5 milliseconds were found to provide acceptable fusing with pulses between 0.5 and 1.2 milliseconds giving better fusing results. It has also been found that longer pulses of energy are required as the power level increases.

The efficiency of the duplex fusing system of the above-described invention can reduce the power required to fuse ordinary simplex copies by as much as 50 percent. It is believed that this is because of the unique configuration of the path through which the copy web is advanced past the flash fusing lamps. It will be further appreciated that the improved flash fusing system will provide improved efficiency even where images are on a single side of theweb material.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. An improved flash fusing apparatus for fusing toner images onto flexible support material comprising a first elongated flash lamp,

a second elongated flash lamp positioned closely adjacent to said first lamp, and

means for advancing flexible support material bearing loose toner images along a predetermined path substantially encircling each of said first and second flash lamps along their longitudinal axes thereof to fuse the toner images thereto. 2. Apparatus according to claim 1 wherein said flexible support material is in the form of a web.

3.,Apparatus according to claim 2 wherein the loose toner images are'on each side of the web.

4. Apparatus according to claim 2 wherein track means guide theweb along its predetermined path.

Claims

1. An improved flash fusing apparatus for fusing toner images onto flexible support material comprising a first elongated flash lamp, a second elongated flash lamp positioned closely adjacent to said first lamp, and means for advancing flexible support material bearing loose toner images along a predetermined path substantially encircling each of said first and second flash lamps along their longitudinal axes thereof to fuse the toner images thereto.

2. Apparatus according to claim 1 wherein said flexible support material is in the form of a web.

3. Apparatus according to claim 2 wherein the loose toner images are on each side of the web.

4. Apparatus according to claim 2 wherein track means guide the web along its predetermined path.