GB2150885A - Image forming apparatus with laminating mechanism - Google Patents

Abstract

An imaging apparatus, such as a copier, facsimile machine and printer, is provided with a lamination processing mechanism. In one form as shown, a transparent film F is supplied onto a sheet S of recording paper having thereon a toner image T, and the recording paper on which the film is placed is moved past an image fixing unit I with the application of pressure and heat thereby causing the film to be fixedly attached to the recording medium. In another form, a combination of recording paper having thereon fixed toner image and a transparent film placed on the recording paper is transported along a predetermined path in which the image fixing unit is disposed, whereby the film becomes fixedly attached to the recording paper as the combination is moved past the image fixing unit. The lamination may be performed on the image-bearing side only, or on both sides. <IMAGE>

Description

SPECIFICATION Image forming apparatus with laminating mechanism This invention generally relates to an image forming apparatus, and, in particular, to an image forming apparatus provided with an image fixing unit which is used for fixing a toner image formed on a recording medium and which may also be used for laminating the recording medium having thereon the fixed image. Specifically, the image forming apparatus of the present invention is suitable for use in copiers, facsimile machines, printers and the like.

A laminating machine for fixedly attaching a transparent film onto an object, such as a sheet of recording paper having thereon recorded information, is well known in the art. Such a laminated recording paper is particularly advantageous because the transparent film fixedly attached onto the recording paper serves as a protective film so that the information recorded on the recording paper may be properly preserved. Lamination is often desired to be carried out for sheets of recording paper on which images have been formed by toner.

Thus, heretofore, if it was desired to produce several copies from an original document and to have them laminated, it was necessary first to operate a copier to produce copies and then to feed the copies thus produced to a laminating machine. However, since it is not always desired to have copies laminated, it is not advantageous to have such a separate laminating machine particularly from the viewpoint of office space.

It is therefore a primary object of the present invention to obviate the above-described disadvantages of the prior art and to provide an improved image forming apparatus which is capable of carrying out laminate processing.

Another object of the present invention is to provide an improved image forming apparatus capable of producing a recorded image on a recording medium and also capable of fixedly attaching a cover film at least on one surface of the recording medium.

A further object of the present invention is to provide an improved image forming apparatus which is increased in convenience in usage and compact in size.

A still further object of the present invention is to provide an improved image forming apparatus having an image fixing unit for fixing toner image formed on a recording medium, which image fixing unit may also be used for fixedly attaching a cover film on the recording medium as a protective film.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Brief description of the drawings Figure 1 is a schematic illustration showing the structure around an image fixing unit in the image forming apparatus constructed in accordance with one embodiment ofthe present invention; Figure 2 is a schematic illustration showing the overall structure of an electrophotographic copier having therein a laminating mechanism constructed in accordance with another embodiment of the present invention; Figure 3 is a fragmentary view showing on an enlarged scale the inlet port of the structure shown in Figure 2; and Figure 4 is a fragmentary view showing on an enlarged scale the inlet port of the structure shown in Figure 2 when both sides of recording medium is to be laminated by a transparent film.

Referring now to Figure 1,there is schematically shown an image fixing unit 1 constructed in accordance with one embodiment of the present invention as applied to an image forming apparatus, such as a copier, facsimile machine and printer. The illustrated image fixing unit 1 includes a cylindrical fixing roller 2 having formed on its outer perpheral surface a silicon resin layer 2a and a cylindrical pressure roller 3 having formed on its outer peripheral surface a fluoride resin 3a. Heat sources 2b and 3b are disposed inside of the rollers 2 and 3, respectively.

As is well known in the art, the image fixing unit shown in Figure 1 normally receives a sheet of recording paper S having thereon a toner image T, which is typically first formed on an imaging member, such as a photosensitive member, by an electrophotographic or electrostatic process and then transferred to the recording paper S. As the recording paper S passes between the two rollers 2 and 3, pressure and heat are applied to the recording paper Sso that the toner image T becomes perma nentlyfixed to the recording paper S.

The image fixing unit 1 shown in Figure 1 is normally used in fixing the toner image T to the recording paper S by applying pressure as well as heat. It is to be noted however that in accordance with the present invention the image fixing unit 1 is also used for laminating a cover film, such as a transparent film, on an object, such as the recording paper S having thereon recorded toner image T. For this reason, in the structure shown in Figure 1,there are provided a film supply roll 10 on which a roll of cover film F is mounted, a decurl roller 11, a pair of transport rollers 12, and a cutter 13 for cutting the film Fto a desired size, which are all arranged to define a path for feeding the cover film F unwound from the supply roller 10 into the image fixing unit 1.

The image fixing unit 1 is partly enclosed by a pair of top and bottom housings 14, each of which has a bent portion 14a which also serves as a guide to lead the cover film F into the pinch point between the rollers 2 and 3.

The supply roller 10 is rotatably supported as fixed in position by a stationary member (not shown) and it supports a roll of cover film F, which is preferably transparent and wound in the form of a roll. As the transparent film F, use is preferably made of polyestes film of approximately 100 microns thick. Such a polyester film includes a thin layer comprised of a thermoplastic material having a melting point which is closer to that of the toner forming image Tat the surface which is brought into contact with the recording paper S. In the preferred embodiment, use is made of an acrylic resin for forming such a thin layer. In addition, the transparent film F is preferably selected to be substantially as wide as the recording paper S.

The decurl roller 11 is rotatably supported and has its rotating axis engaged with one end of a tension spring 15 whose other end is engaged with a fixed point, for example, on a stationary member (not shown). The decurl roller 11 is so disposed with its rotating axis loosely fitted in and movable along slots 16, for example, formed on the stationary member, so that the decurl roller 11 is located at a position in which the tension applied by the spring 15 balances with the tension applied by the transpa rentfilm F.In this manner,thetransparentfilm Fis properly maintained in tension, and since the transparent film F moves around the decurl roller 11 under tension in the direction opposite to the winding direction in the roll on the supply roller 10, its tendency to curl may be eliminated or substantially reduced.

The pair of transport rollers 12 is so disposed to pinch the transparent film F, and at least one of the transport rollers 12 is coupled to a driving system (not shown) so that the transport rollers 12 are driven to rotate to positively feed the transparent film F into the image fixing unit 1. The cutter 13 includes a pair of blade members which are disposed on both sides of the transparent film F, and when a signal is applied to the cutter 13 by detecting the trailing edge of the recording paper S to be subjected to laminate processing, the blade members are activated at proper timing to cut the transparent film F in accordance with the length of recording paper S to be processed. It is to be noted that a pair of laminate processing mechanisms identical in structure is provided in the structure illustrated in Figure 1.With this structure, both sides of the recording paper S may be laminated by the transparent film F, if desired.

In operation, in the structure shown in Figure 1, if it is desired to carry out laminate processing, the operator first turns on a selection switch (not shown) for selecting a lamination mode, which is preferably provided in a control panel of the present image forming apparatus. When the selection switch is so turned on, an associated control mechanism (not shown) provided in the present image forming apparatus is activated. Thus, when a paper detecting sensor disposed at a point along a path for transporting the recording paper S or in a feed roller for feeding the recording paper S into the transporting path from a stack of recording paper in a storing section detects the presence of recording paper S, the control mechanism initiates counting of clock pulses.Based on the count of clock pulses and the transportation speed and distance of recording paper S, the control mechanism determines the timing at which the leading edge of transparent film F may be brought into registry with the leading edge of recording paper S and causes the transportion rollers 12 to start to rotate on the basis of the timing thus determined. In this manner, the leading edges of recording paper S and transparent film F are fed into the pinch point between the two rollers 2 and 3 at the same time, whereby laminate processing is carried out with the application of heat and pressure thereby causing the transparent film F to be laminated onto the recording paper S.Then, the control mechanism operates the cutter 13 at a proper timing which is determined in accordance with the length of recording paper S to be processed so that the transparent film F is severed by the cutter 13 to be substantially of the same length as the recording paper S to be processed.

Figure 2 illustrates an image transfer type electrophotographic copying machine which is constructed in accordance with one embodiment of the present invention. As shown, the illustrated copier includes a cassette 16 for storing therein a stack of recording paper S, a feed roller 17 for feeding the recording paper S one by one from the stack in proper timing, paper transportation rollers 18 and 19 for transporting the recording paper S from the cassette 16 along a predetermined path, a photosensitive drum 20 which is driven to rotate in a predetermined direction, a corona charging unit 21 for charging the peripheral surface of the drum 20 uniformly to a predetermined polarity, a light shielding plate 22 for defining an exposure region for exposing the charged drum surface to a light image thereby forming an electrostatic latent image on the drum surface, a developing unit 23 for developing the latent image by selective application of toner, a corona transfer unit 24 for transferring the toner image formed on the drum surface onto the recording paper S from the cassette 16, a transporting belt 25 for transporting the recording paper S now having thereon the transferred toner image to the image fixing unit 1, and a paper tray 26 for storing thereon the recording paper S discharged out of the image fixing unit 1. All of the above-mentioned elements, excepting the paper tray 26, are disposed within a machine housing, and the cassette 16 is detachably mounted as half-inserted into the housing. It is to be noted that the image fixing unit 1 itself shown in Figure 2 is similar in structure to that shown in Figure 1.

In this embodiment, a table 27 is provided as fixedly mounted on the machine housing located above the paper tray 26. The machine housing is formed with an insertion opening 28 at the location where the table 27 is fixedly attached to the machine housing. A pair of guide rollers 29 are disposed adjacent to the insertion opening 28 for leading an object, e.g., recording paper S after recording, into a path defined in the machine housing. Also provided within and fixedly attached to the machine housing is a curved plate 30 generally extending from the opening 28 to the image fixing unit 1. Another pair of guide rollers 31 are disposed between the forward end of the curved plate 30 are disposed between the forward end of the curved plate 30 and the image fixing unit 1. The image fixing unit 1 is generally enclosed by top and bottom housings 14 which have bent portions 14a and 14a', respectively, thereby defining an inlet opening to the image fixing unit 1.

The detailed structure around the insertion opening 28 is shown on an enlarged scale in Figure 3. As shown in Figure 3, a light emitting element 30a is fixedly attached to the machine housing and a light receiving element 30b is also fixedly attached to the machine housing so as to receive the light emitted from the light emitting element 30a and travelling across the space defined by the insertion opening 28. As an alterative structure, use may be made of a microswitch or feeler switch in place of a combination of light emitting and receiving elements 30a and 30b.

When carrying out laminate processing with the present embodiment as structured above, the recording paper S on which toner image T has already been formed and fixed is placed on the table 27 with a sheet of transparent film F placed on the recording paper S and the recording paper S having thereon the sheet of transparent film F is then inserted into the insertion opening 28. When the leading edge of a combination of superposed recording paper S and transparent film F passes through the gap between.

the light emitting and receiving elements 30a and 30b, a detection signal is generated by the light receiving element 30b, which is then supplied to a control unit (not shown) to have the guide rollers 29 and 31 set in rotation. It is to be noted that upon generation of such a detection sigal, the control unit prohibits the ordinary reproduction process from taking place at least until the current laminate processing has been completed.

As an alternative embodiment, it may be so structured that transparent film F is fed into the image fixing unit 1 in synchronism with the recording paper S having thereon toner image Twhich has just been transferred from the drum 20 by the corona transfer unit 24 and which has not yet been fixed. In this case, the transparent film F already cut to appropriate size in the form of cut sheet may be fed from the table 27, or, if desired, the film supplying mechanism shown in Figure 1 may be incorporated into the copier 2.

Figure 4 illustrates the case in which both sides of recording paper S are to be laminated by a single sheet of transparent film F. In this case, the singel sheet of transparent film F is placed around the recording paper S as folded into half and such a combination is inserted into the insertion opening 28. Of course, the folded end must first be inserted into the insertion opening 28 in this case. As an alternative embodiment, the dual film supplying mechanism shown in Figure 1 may be incorporated into the copier of Figure 2 or the recording paper S may be processed twice, once right side up and then upside down, in the copier having the structure shown in Figure 2 so as to have both sides of recording paper S laminated.

While the above provides a full and complete disclosure of the preferred embodiments of the present invention, various modifications, alternate constructions and equivalents may be employed without departing from the true spirit and scope of the invention. Therefore, the above description and illustration should not be construed as limiting the scope of the invention, which is defined by the appended claims.

Claims (15)

1. An imaging apparatus comprising: image forming means for forming a toner image on a recording medium; image fixing means for fixing said toner image to said recording medium with the application of pressure as well as heat thereto; and film supplying means for supplying a film to be placed on said recording medium before said recording medium enters into said image fixing means, whereby said film becomes fixedly attached to said recording medium when exiting from said image fixing means.

2. The apparatus of claim 1 wherein said image fixing means includes a pair of rollers which are driven to rotate in opposite directions thereby causing said recording medium to pass thereby causing said recording medium to pass therebetween under pressure and heater means for applying heat to said recording medium.

3. The apparatus of claim 2 wherein said heater means includes a pair of heat sources which are disposed inside of said rollers, respectively.

4. The apparatus of claim 1 wherein said film supplying means supplies said film onto that surface of said recording medium on which said toner image is formed.

5. The apparatus of claim 4wherein said film supplying means has a dual structure for supplying said film on both sides of said recording medium.

6. The apparatus of claim 1 wherein said film is polyester film.

7. The apparatus of claim 6 wherein said polyesterfilm is approximately 100 microns in thickness.

8. The apparatus of claim 6 wherein said polyesterfilm is provided with a thin layer comprised of a thermoplastic material having a melting point which is substantially close to that of said toner.

9. The apparatus of claim 8 wherein said thermoplastic material is an acrylic resin.

10. The apparatus of claim 1 wherein said supplying means includes storing means for storing said film, feeding means for feeding said film to said image fixing means and cutting means for cutting said film to a desired size.

11. The apparatus of claim 10 wherein said storing means includes a supply roller for supporting thereon a quantity of said film in the form of a roll, and said feeding means includes at least one transportation rollerforfeeding said film unwound from the roll on said supply roller into said image fixing means and biasing means for keeping said film in tension.

12. An imaging apparatus comprising: a main housing; firsttransporting meansfortransporting a recording medium along a first transportation path defined in said main housing from a first position to a second position, which are previously determined in said main housing; image forming means disposed in said main housing at a point along said first transportation, path for forming a toner image on said recording medium; image fixing means disposed at said second position for fixing said toner image to said recording medium with the application of pressure as well as heat thereto while said recording medium passes therethrough; and second transporting means disposed along a second transportation path defined in said main housing as extending from a third positin previously determined in said main housing to said second position, said second transporting means being capable of transporting at least a film to be laminated onto said recording medium by passing through said image fixing means.

13. The apparatus of claim 12 wherein said second transporting means includes a table fixedly attached to said main housing at said third point, an insertion opening formed in said main housing adjacent to said table, a curved plate extending between said insertion opening and said image fixing means, and at least one guide roller for moving at least said film along said curved plate.

14. The apparatus of claim 12 wherein said second transporting means being capable of transporting a combination of said recording medium and said film superposed on said recording medium along said second transporting path while keeping said image forming means inoperative.

15. An imaging apparatus substantially as herein described with reference to Figure 1 of Figures 2 to 4 of the accompanying drawings.