MXPA00007255A - Nip width converting mechanism for use in a fusing apparatus. - Google Patents

Abstract

According to the present invention, there is provided a fusing nip width converting mechanism and a compact long nip width fusing apparatus including such a mechanism are disclosed for use in a reproduction machine. The compact long nip width fusing apparatus includes a rotatable fuser roller and a rotatable pressure roller forming a roller nip against the rotatable fuser roller. Importantly, the fusing nip width converting mechanism includes a first belt directing roller for positioning on an exit side of the roller nip formed by the rotatable fuser roller and the rotatable pressure roller, a second belt directing roller for positioning on an entrance side of the roller nip, and an endless belt member mounted over the first belt directing roller, through the roller nip, and over the second belt directing roller, forming a closed loop thereof. The closed loop of the belt member as mounted is pinched and deflected by the rotatable fuser roller and the rotatable pressure roller within t he roller nip, and the closed loop as pinched forms a long width fusing nip against the rotatable fuser roller, thereby increasing fusing dwell time and fusing thermal efficiency, relative to the roller nip. The compact long nip width fusing apparatus as such is suitable for use in an electrostatographic reproduction machine for producing high quality fused toner images.

Description

MECHANISM OF CONVERSION OF THE WIDTH OF THE CONTACT POINT AND COMPACT FUSION APPARATUS THAT INCLUDES THE SAME DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION This invention relates generally to electrostatic reproduction machines, and more particularly to a mechanism for converting the width of the contact point of a compact melting apparatus including such a mechanism for use in a machine for increase the contact time of the fusion and the thermal efficiency of the fusion. In a typical electrostatic printing process, a photoconductive member is charged to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to selectively dissipate the charges on it in the irradiated areas. This records a latent electrostatic image on the photoconductive member. After the latent electrostatic image is recorded on the photoconductive member, the latent image is revealed by contacting it with a revealing material. In general, the developer material comprises pigment particles REF: 121557 organic that adhere triboeléctricamente to carrier granules. The organic pigment particles are attracted from the carrier granules either to a donor roller or to a latent image on the photoconductive member. The organic pigment attracted to a donor roller is then deposited on latent electrostatic images on a charge retaining surface, which is usually a photoreceptor. The organic pigment powder image is then transferred from the photoconductive member to a copying substrate. The organic pigment particles are heated to permanently fix the powder image to the copying substrate. In order to fix or melt the organic pigment material on a support member permanently by heat, it is necessary to raise the temperature of the organic pigment material to a point at which the constituents of the organic pigment material coalesce and become sticky. This action causes the organic pigment to flow to some degree on the fibers or pores of the support members or otherwise on the surfaces thereof. Subsequently, when the organic pigment material cools, the solidification of the organic pigment material occurs causing the organic pigment material to be firmly attached to the support member. , -,.-..--- «-" - ._-_-___ ,, ".__ < _.,. . -, tÉ £ & to ^ < ¡~ F ^ -jM * í ^.-.-... A -..- __- ... . -A .--- ^.-.. - .- A method for the thermal fusion of images of organic pigment material on the support substrate has been to pass the substrate with images of organic pigment without melting on it between a pair of opposite members in the form of a roller, at least one of which is heated internally. During the operation of such a fusion system, the support member to which the organic pigment images are electrostatically adhered moves through the point of contact formed between the rolls with the organic pigment image in contact with the roller of the pigment. hot melter, to effect therefore the heating of the organic pigment images within the contact point. In a Fuser Roll Forming a Contact Point (NFFR), the hot melter roller is provided with a layer or layers that are deformable by a harder pressure roller when the two rollers are engaged by pressure. The length of the contact point determines the contact time or time at which the organic pigment particles remain in contact with the surface of the hot roll. Roller melters work very well to melt color images at low speed since they require process conditions such as temperature, pressure and contact that can be achieved easily. When process speeds approach 100 pages per minute (ppm) the operation of the melter roller starts to fail. At such high speeds, the contact time must remain constant, which requires an increase in the width of the contact point. The increase in the width of the contact point can be achieved more easily by increasing the thickness of the rubber of the melter roller (FR) and / or external diameter of the roller. Each of these solutions reaches its limit at approximately 100 ppm. Specifically, the thickness of the rubber is limited by the maximum temperature that the rubber can resist and the thermal gradient across the elastomeric layer. The size of the roller becomes a critical aspect for reasons of space, weight, cost and disassembly. Following is a discussion of the prior art, incorporated herein by reference, which may support the patentability of the present invention. In addition to possibly having some relevance to the question of patentability, those references, together with the following detailed description, may provide a better understanding and appreciation of the present invention. U.S. Patent No. 5,250,998 issued to Ueda et al on October 5, 1993 describes a device for fixing organic pigment images, where an endless band wrapped around a roller is provided. heating and a transport roller, a pressure roller for pressing a sheet having an organic pigment image on the heating roller with the endless band intervening between the pressure roller and the heating roller. A sensor is deposited within the ring of the band to come into contact with the heating roller, to detect the temperature of the heating roller. The fixing temperature for the organic pigment image is controlled on the basis of the temperature of the heating roller detected by the sensor. A first region of the contact point is formed on a pressing portion located between the heating roller and the fixing roller. A second region of contact point is formed between the band and the fixing roller continuing from the first region of contact point but without coming into contact with the heating roller. U.S. Patent No. 5,465,146 issued to Hgashi et al on November 7, 1995 is related to a fixation device to be used in electrophotographic apparatuses to provide a fixed, clean image, without deviation, without the use of oil or. The smaller amount of oil, where an endless fastening strip is provided with a metal body having a thin film peelable thereon stretched between the - ^ || ¡__ i _---- i-A.i.1 || j j¡ | ij. .. - _-.-.-.._, ____ -., "," -,. ., -. "&;« __, _ «.... X £, _-, _-__ &. • • • fixing roller having an elastic surface and a heating roller, a roller of pressure arranged to press the surface of the elastic fixing roller up the lower side thereof through the fixing band to form a contact point portion between the fixing band and the pressure roller, a guide plate is provided for the support medium containing the unfixed image, to substantially form a linear heating path between the guide plate and the fixing band, and the metal body of the fixing band has a heat capacity per cm2 within the range of 0.001 to 0.02 cal / ° C.

BRIEF DESCRIPTION OF THE INVENTION According to the present invention, a mechanism for converting the width of the fusion contact point and a melting apparatus with a large, compact point of contact width for use in a reproduction machine is described. . The melting apparatus with a large, compact point of contact width includes a rotating melter roller and a rotating pressure roller that form a contact point between rollers against the roller of the rotating melter. Importantly, the mechanism that converts the width of the fusion contact point includes a first roller that directs the band to be placed on a the exit side of the roller contact point formed by the roller of the rotary melter and the rotary pressure roller, a second roller that directs the band to place it on an input side of the contact point between rollers, and a band member without end mounted on the first director roller, through the point of contact between rollers, and on the second band that directs the roller, forming a closed circuit on it. The closed circuit of the band member as assembled is tightened and biased by the rotary melter roller and the rotating pressure roller within the roller contact point, and the closed circuit as it is tightened forms a wide melting contact point. large against the roller of the rotating melter, thus increasing the melting contact time and the thermal efficiency of the melt, relative to the point of contact between rollers. The melting apparatus with a large, compact point of contact width as such is suitable for use in an electrostatic reproduction machine to produce high quality cast organic pigment images.

DESCRIPTION OF THE DRAWINGS In the detailed description of the invention presented below, reference is made to the drawings, in which: a »_x_? _- Yes _--? _- a_. .-. »FIGURE 1 is a schematic illustration of an electrostatic reproduction machine incorporating the contact point width conversion mechanism and the fusion apparatus of the present invention; FIGURE 2 is a perspective representation of the mechanism of conversion of the width of the contact point of the machine of FIGURE 1; and FIGURE 3 is a detailed, schematic end view of the contact point width conversion mechanism and the fusion apparatus of FIGURE 1 according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Although the present invention will be described in relation to preferred embodiments thereof, it should be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents that may be included within the spirit and scope of the invention as defined by the appended claims. For a general understanding of the features of the present invention, reference is made to the drawings. In the drawings, similar reference numbers have been used throughout to identify identical elements.

«I t -j.i-. »--_.» ----- », b * > - -.-. ------- ll - * --- to-¿> fa - ^ -_--, ----- t- Referring now to the drawings (FIGURE 1), where what is shown is for the purpose of describing a preferred embodiment of the invention and not to limit it, and where several process stations were used in an electrostatic reproduction machine as illustrated in FIGURE 1, they will be described only briefly. As illustrated, an electrostatic reproduction machine 8, in which the present invention finds use, utilizes a member that contains an image that retains charge in the form of a photoconductive strip 10 consisting of a photoconductive surface 11 and a substrate that transmits light , electrically conductive. The strip 10 is mounted to move along a series of stations of the electrostatic process including an AA charging station, a BB display station, DC developer stations, DD transfer station, EE fusion station and FF cleaning station. . The band 10 moves in the direction of the arrow 16 to successively advance the portions thereof sequentially through the different processing stations placed around the path of movement thereof. The band 10 enters around a plurality of rollers 18, 20 and 22, the first of which can be used to provide adequate tension of the photoreceptor band 10. The roller 20 is coupled to a motor 23. ^ ^ ^ | g? |. ... ^^ .--- ^ a-- by suitable means such as a band accuser. The motor 23 rotates the roller 20 to advance the web 10 in the direction of the arrow 16. As can be seen with further reference to FIGURE 1, initially the successive portions of the web 10 pass through the charging station AA. In the AA charging station, a corona discharge device such as a scorotron, corotron or dicorotron indicated generally by the reference numeral 24, loads the band 10 to a positive or negative potential uniformly high, selective. Any suitable control, well known in the art, can be employed to control the corona discharge device 24. The portions are then advanced. charged from the photoreceptor surface through the exposure station BB. In the exposure station BB, the photoresistor or surface retaining uniformly charged charge 10 is exposed to a laser based input and / or output scanning device 25 which, when controlled by the controller or ESS 26, causes the surface retaining charge to be discharged according to the output of the scanning device. The ESS 26, for example, is the main multi-tasking processor to operate and control all the other sub-systems of the machine including aspects of the present invention. He i II__ÍÉ-WÉ-IÍ > IGIÍÍ t ----------.-.. - .- fc? Itai.-.... ----.. --- ..._..-., »-, . h,? tA_á. _i -, _-- a-i .... _ ^ - ^. .._. ,,.

Scanning device is a three-level laser exit screen (ROS) scanner. The resulting photoreceptor contains images in a loaded area and images in an unloaded area. In the DC developing station, a developing system, indicated generally by the reference numeral 30, has advanced developing materials in contact with the latent electrostatic images, and reveals the image. The developing system 30, as shown, comprises first and second developer apparatuses 32 and 34. The developer apparatus 32 comprises a housing containing a pair of magnetic brush rolls 35 and 36. The rollers advance the developer material 40 in contact with each other. with the photoreceptor to reveal the images of the downloaded area. The developer material 40, by way of example, contains negatively charged organic pigment. The electrical deflection is achieved via the power source 41 electrically connected to the developing apparatus 32. A deviation of CD is applied to the rollers 35 and 36 via the energy source 41. The developing apparatus 34 comprises a housing containing a pair of rollers of magnetic brush 37 and 38. The rollers advance the developer material 42 in contact with the photoreceptor to develop the images of the charged area. The developer material 42 by way of ^ and example contains black organic pigment positively charged to reveal the images of the charged area. The appropriate electrical deviation is achieved via the power source 43 electrically connected to the developing apparatus 34. A deviation of CD is applied to the rollers 37 and 38 via the deviation energy source 43. Because the composite image developed on the photoreceptor consists of positive and negative organic pigment, a pretransfer corona discharge member 56 is provided to condition the organic pigment for effective transfer to a substrate using a corona discharge of a desired polarity, either negative or positive. The sheets or substrate or support material 58 are advanced to the transfer station DD from a feeder tray, not shown. The sheets are fed from the tray by means of a sheet feeder, also not shown, and are advanced to the transfer station DD through a crown loading device 60. After transfer, the sheet continues to move on the direction of the arrow 62 towards the fusion station EE. As illustrated, the fusion station EE has a compact band fusion apparatus 90 according to the present invention which includes the conversion mechanism of the width of the contact point 100 according to the present invention. As illustrated, the melting apparatus 90 includes a roller of the rotary melter 92. The melter roller 92 is heated for example by a heating device 94 (shown as an internal lamp but could also be an external heater) to raise the temperatures from the surface 96 of the melter roller to a suitable organic pigment melting temperature. The melting apparatus 90 also includes a rotating pressure roller 98 that forms a contact point between rollers 99 against the roller of the rotary melter 92. Importantly, the compact melting apparatus 90 includes the mechanism of conversion of the width of the point of fusion contact 100 to increase the melting contact time and the thermal efficiency of the melt in relation to the contact time of the roller contact point and the thermal efficiency of the melt. Referring now to FIGURES 1-3, and in particular to FIGURE 2, the contact point width conversion mechanism 100 includes a first roller that directs the web 102 to place it on an exit side of the roller contact point. 99, and a second roller that directs the web 104 to place it on an inlet side of the contact point between rollers 99. Each of the rollers directing the web 102, 104 may comprise an extruded aluminum member. How I know f? iti ¡ni M ___ ltlh.ttÍ_ÉÉtl T rIr trÜf * "* - * - - ----» «•. - .. ^^ - J.-_? - ¿_. ^ -.__. ,,. ____,. ..- .., .._-,, ._., .____- further shows, the width conversion mechanism, contact point 100 also includes an endless band member 106 which is mounted on the first roller directing the band 102, and on the second roller directing the band 104, thereby forming a definable or compressible closed circuit 108 thereof, around the rollers 102, 104 (FIG. 2). Conversion of the width of the contact point 100 is mounted to form a melting contact point converted in accordance with the present invention (FIGURE 3), the endless band member 106 is mounted on the first roller directing the band 102, a through the contact point between rollers 99, and on the second roller that directs the band 104, where the definable or compressible closed circuit 108 is compressed or squeezed and deflected by the roller d the rotary melter 92 and the rotary pressure roller 98 within the contact point between rollers 99 as shown. Advantageously, the closed circuit 108 when tightened forms a large-width melting contact point 110 against the roller of the rotary melter 92 by converting the contact point between rollers of comparatively short width 99 into a large-width contact point 110. The conversion therefore increases the melting contact time and the thermal efficiency of the fusion, relative to the same of the contact point between rollers 99. According to other aspects of the present invention, the large-width melting contact point 110 includes two highly comparative contact point pressure areas, which comprise an area input 112 at the wide-width melting point of contact, and an exit area 114 thereof. As shown, the first pressure area of the high contact point 112 in the inlet towards the large width melting contact point is created by the melter roller 92 which tightens or compresses a portion of a closed circuit leg 108 against the second roller that directs the band 104. Similarly, the second pressure area of the high contact point 114 at the exit thereof is created by the melter roller 92 which tightens a portion of a closed circuit leg 108 against the first roll directing the band 102. Although both rolls directing the band 102 and 104 are preferably floating tension rolls held in place only by the closed circuit 108 of the band member 106, the fusion apparatus 90 and the conversion mechanism of the contact point width 100 work equally well with only one of the rollers that direct the band being a tension roller. In the preferred embodiment with both rollers directing the belt being tension rollers, either the rotary melter roller 92 or the rotary pressure roller 98 is a tension roller. Summarizing, the fusion apparatus 90 uses a single floating tension roller and a band mechanism 100, mechanism 100 in which a pair of tension roller 102, 104 are held in position only by a closed circuit 108 of a member of band 106. Tension rolls 102, 104, therefore, have no conventional radial bearing or positioning mechanism. This allows for a simple design that is compact, thermally efficient, and inexpensive when compared to other band melters that have a similar wide-width melting contact point. As indicated above, the pressure profile of the wide-width melting contact point 110 of the present invention is also unique since the areas of higher pressure (two of them) may be in the entrance area of the contact point 112. , and in the exit area of the contact point 114. Referring still to Figures 1-3, the melter roller 92 is preferably the drive roller and is mounted in a fixed position in a suitable frame 93 through a pair of end bearings 122 (not shown). On the other hand, the pressure roller 98 is also mounted on the frame 93, but moves towards and away from the roller of the .-to- . - > .-_-.-.__-, - ..--- * -_-.-,!. • - Jit'Miirf-itm - * «^ * -» ..- »« * -. * • «J" "* - '" .-, -_.-. fuser 92 (arrow 118), and can be loaded with a force F as by a spring 120 towards the melter roller 92. The load of the contact point and the web tension are determined in this way by the load or force F applied to the pressure roller 98. The floating tension rollers 102, 104 are held in their respective band direction positions only by the closed circuit 108 of the band member 106. As noted above, those tension rollers as assembled in the mechanism 100, and the fusion apparatus 90 do not have conventional radial bearing or positioning mechanisms. They only need some form of thrust bearing 124 at each end thereof (Figure 2) to locate them laterally against the end bearings of the fuser roll 92. The mechanism 100 (combination of tension roll / loop or the web) is maintained in its point of contact conversion position within the contact point between rollers 99 only by the melter and pressure rollers 92, 98 respectively. In operation, the copying means 58 with an unmelted organic pigment image 89 on the upper side as shown, enters the large-width melting contact point 110 through the entrance area 112, and leaves the contact point 110 through the exit area 114. The entrance of the contact point of the high pressure area li. i ------ & ^ _ ^ £ tg ^ ii ^ g will advantageously minimize wrinkling and other deformities on the incoming medium or sheet and the outlet of the contact point of the high pressure area will act to improve the fixation of the molten image on the medium or sheet 58. As can be clearly seen, the organic pigment sheet is in contact with the hot surface 96 of the melter roller 92, and a much greater distance in such contact is displaced through of the contact point 110, compared for example with the displacement through the point of contact between rollers 99. Therefore, the melting contact time, at a given speed of displacement, will be significantly greater through the point of contact of large width 110 compared to a contact point between rollers, for example the contact point 99. Advantageously, the conversion mechanism of the contact point 100 and the fusion apparatus 90 result in a contact band fusion apparatus having a relatively small total surface area of the band compared to other band fusion systems. The compact structure and small surface area minimize heat loss and require less energy for its operation. Melting tests on a compact melting apparatus in accordance with the present invention found a resultant reduction of 84 ° F (28.88 ° C) at a required melting temperature compared to a hot melt and pressure roller melting apparatus or conventional. Additionally, the band member 106 is relatively short and consequently relatively less expensive as well, and the rollers that direct the band can also be inexpensive. As can be seen, a mechanism for converting the melting point width and a compact, large contact point melting apparatus including such a mechanism for use in a reproduction machine has been provided. The large, compact point-contact melting apparatus includes a rotating melter roller and a rotating pressure roller that form a point of contact between rollers against the rotating melter roller. Importantly, the mechanism for converting the melting contact width includes a first roller that directs the band to place it on an exit side of the roller contact point formed by the rotating melter roller and the rotating pressure roller., a second roller that directs the band to place it on an input side of the contact point between rollers, and a band member without mounted on the first roller that directs the band, through the point of contact between rollers, and on the second roller that directs the band, forming a closed circuit of the same. The closed circuit of the band member as assembled is tightened and biased by the rotating melter roller and the rotating pressure roller within the roller contact point, and the closed circuit as it is tightened forms a wide melting contact point. large against the roller of the rotating fuser, thereby increasing the contact time of fusion and the thermal efficiency of the melt, in relation to the point of contact between rollers. Although the invention has been described in conjunction with a particular embodiment thereof, it will be apparent that many alternatives, modifications and variations may be apparent to those skilled in the art. Accordingly, the present invention is intended to encompass all those alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. , -. _- .. ». . »-.- ÉÉIÍ-I» --- -A ----.-. ^ A .. -_ .. 4t --i -. »- t ...

Claims (15)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. 1. A mechanism for converting the width of the fusion contact point to convert a melting contact point of the short width roll to a large width band melting contact point, to increase the melting contact time and the thermal efficiency, the mechanism of conversion of the melting point width is characterized in that it comprises: (a) a first roller that directs the strip to place it on the exit side of a melting contact point of the roller formed by a melting roller hot, rotating and a rotating pressure roller; (b) a second roller directing the strip to place it on the entry side of the melting contact point of the roller; and (c) an endless band member mounted on the first roller that directs the band and on the second roller that directs the band, the band member as it is mounted - forms a closed circuit thereof, the closed circuit of the member Belt can be tightened by the hot, rotating melter roller and the pressure roller within the melting contact point of the roller, and when it is tightened,
2. _._. .. ..- > .-_-_,. «-_._., Jtdí? I to_J» - ^ -; --- J-j_, .--- aw .. - -. a, - - i Hitl &li-iirir forms a melting contact point of the wide-width band, in relation to the roll melting contact point, resulting in an increase in the melting contact time and an increase in the thermal efficiency of the fusion. The mechanism for converting the width of the contact point of fusion according to claim 1, characterized in that the first roller that directs the band and the second roller that directs the band is a tension roller.
3. 3. The mechanism for converting the melting point width according to claim 1, characterized in that both of the first roller that directs the band and the second roller that directs the band are tension rollers.
4. 4. The mechanism of conversion of the width of the contact point of fusion according to claim 1, characterized in that the first roller that directs the band and the second roller that directs the band comprise an extruded aluminum member. The mechanism for converting the width of the contact point of fusion according to claim 3, characterized in that the band member comprises an extruded aluminum strip, each of the first roller that directs the band and the second roller that directs the band is a
5. floating tension roller held in place by the closed circuit of the band member.
6. 6. A melting apparatus with a large, compact point of contact width, characterized in that it comprises: (a) a rotating melter roller; (b) a rotating pressure roller that forms a point of contact between rollers against the roller of the rotary melter; and (c) a melting contact arc conversion mechanism that includes: (i) a first roller that directs the strip to place it on an exit side of the roller contact point formed by the roller of the rotary melter and the rotating pressure roller; (ii) a second roller that directs the band to place it on an inlet side of the contact point between rollers; and (d) an endless band member mounted on the first roller which directs the band, through the point of contact between rollers and on the second roller that directs the band and which forms a closed circuit thereof, the closed circuit of the band member is compressed or squeezed and deflected by the rotating melter roller and the rotary pressure roller within the roller contact point, and the closed circuit as it is pressed or

   ¡¡¡¡¡¡¡A tightly formed large melting contact point against the rotating fuser roller, thus increasing the contact time of fusion and the thermal efficiency of the fusion, in relation to the point of contact between rollers.
7. 7. The melting apparatus with a large, compact point of contact width, according to claim 6, characterized in that the large-width melting contact point includes three comparatively high contact point pressure areas, comprising a entrance area at the large-width fusion point of contact, and an exit area thereof, and an area that coincides with the point of contact between rollers.
8. 8. The melting apparatus with a large, compact contact point width, according to claim 6, characterized in that one of the first roller that directs the band and the second roller that directs the band is a tension roller.
9. 9. The melting apparatus with a large, compact contact point width, according to claim 6, characterized in that one of the rotating melter roller and the rotary pressure roller is a drive roller and both of the first roller that directs the band and the second roller that directs the band are tension rollers.
10. 10. The melting apparatus with a large, compact point of contact width, according to claim 6, characterized in that the band member comprises an extruded aluminum strip.
11. 11. The melting apparatus with a width of the contact point jrande, compact, according to claim 6, characterized in that each of the first roller that directs the band and the second roller that directs the band is a floating tension roller kept in place by the closed circuit of the band member.
12. 12. An electrostatic reproduction machine, characterized in that it comprises: (a) a mobile member that contains an image, having a surface that carries an organic pigment image that defines a path of movement thereof; (b) electrostratigraphic devices mounted along the path of motion to form an organic pigment image on the surface carrying the organic pigment image; (c) means for transferring the organic pigment image from the surface carrying the organic pigment image onto a substrate; and (d) a melting apparatus with a large, compact point of contact width to heat and melt the image of
13. organic pigment on the substrate, the melting apparatus with a large, compact point of contact width, includes a melter roller and a pressure roller that form a point of contact between rollers, (i) a first roller that directs the band to place it on an exit side of the roller contact point, (ii) a second roller that directs the band to place it on an inlet side of the roller contact point, and (iii) a mounted endless band member on the first roller that runs the band, through
14. 10 of the contact point between rollers, and on the second roller that directs the band forming a closed circuit thereof, and the closed circuit is pressed forming a large-width melting contact point against the roller of the rotary melter, increasing by so the time of
15. 15 fusion contact and the thermal efficiency of the fusion, in relation to the contact source between rollers.

    - ~ * Aa * _, - «-. . .....To you---.-. -, __.___ «.., ..,. * ._. Toul-« l? .ftÍÉi ^ SUMMARY OF THE INVENTION A mechanism for converting the width of the fusion contact point and a fusion apparatus with a large, compact point of contact width, including such a mechanism for use in a reproduction machine. The melting apparatus with a large, compact point of contact width includes a rotating melter roller and a rotating pressure roller that form a contact point between rollers against the rotating melter roller. Importantly, the mechanism for converting the melting point width includes a first roller that directs a band to be placed on the exit side of the roller contact point formed by the rotating melter roller and the rotary pressure roller, and a second roller that directs a band to place it on an inlet side of the roller contact point, and an endless band member mounted on the first roller that directs the band, through the point of contact between rollers, and on the second roller that directs the band, forming a closed circuit of the same. The closed circuit of the band member as assembled is pressed and deflected by the rotary melter roller of the rotating pressure roller within the roller contact point, and the closed circuit as it is driven forms a large wide melting contact point. against the rotating fuser roller, increasing

    . _- ..? «-. J-j-jéa s. _-, -.. ---. - __--. - * _ * _-. * • therefore the fusion contact time and the thermal efficiency of the fusion, in relation to the contact point of the roller.

    -, - ^ .Í - & - *