GB1561851A

GB1561851A - Photocopying

Info

Publication number: GB1561851A
Application number: GB5446376A
Authority: GB
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1976-12-31
Filing date: 1976-12-31
Publication date: 1980-03-05

Description

(54) IMPROVEMENTS IN AND RELATING TO PHOTOCOPYING (71) We, XEROX CORPORATION of Xerox Square, Rochester, New York, United States of America, a corporation organized under the laws of the State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates generally to photocopying and the handling of sheets or the like carrying information to be reproduced.

For convenience such sheets or the like are hereinafter and in the claims referred to as originals, although it is to be understood that these may themselves be copies, and bundles of such originals are referred to as documents. More particularly, the invention is concerned with original handling apparatus for use in photocopying machines, particularly electrophotographic copying machines.

It has heretofore been proposed to feed originals to an imaging station seriatim from a stack. For example in our U.S. Patent Specification No. 3,630,515, there is described a recirculating original handling system in which originals are fed seriatim from a supply tray to an imaging station and returned to the supply for either recycling or removal. The system includes a feeder for feeding one original at a time from the bottom of the supply to the imaging station and back to the tray, and a bar to segregate originals returning to the tray from other originals awaiting feeding, at least until the supply of other originals is used up. Such apparatus may be programmed to precollate the copies by repetitively feeding the originals in sequence and making one copy of each original at a time.

Or it may be used in conjunction with a sorter in which case multiple copies limited only by the capacity of the sorter may be made of each original before the next one is fed, i.e. post-collation.

In British Patent Specification No.

1,459,228 there is described an original handling apparatus which enables precollation of copies and which comprises an endless belt having a plurality of original receiving pockets that is driven past an original illumination station of a copier.

U.S. Patent Specification No. 2,194,808 describes an original handling system which permits both sides of the original to be copied. The originals are held between a pair of endless transparent belts which carry the originals past a camera. The belts follow a U-path so that each document is carried twice past the camera with first one side and then the other facing the camera.

While this provides for the copying of both sides of an original the side seen by the camera during the reverse run of the belt has to be viewed in a gap between originals passing along the forward run. Also it is difficult to arrange the copies in a logical order.

It is an object of this invention to provide in a photocopying machine an original handling apparatus which permits copying of both sides of a document in which the above difficulties are alleviated.

To this end, the invention consists in a photocopying machine including an original illumination station, an original handling apparatus comprising an endless belt adapt ted to support a plurality of originals with both surfaces thereof visible to view, a moebius twist in said belt spaced along the belt path from the original illumination station, and means for driving the belt past the original illumination station.

The photosensitive surface of a photocopying machine may be exposed to a light pattern of an image of the information on an original to be reproduced by scanning a stationary original using a moving illumination source and a moving optical system or by moving the original past a stationary illumination source and optical system. A third method is to use flash exposure where both the light source and the original are stationary during the exposure step. Apparatus of this invention may be utilised in machines employing any of these- exposure methods and accordingly the belt drive means may be arranged to drive the belt continuously or stepwise.

The belt may support the documents in transparent, original receiving pockets spaced therealong, and for this purpose the belt may be of transparent plastics material the pockets being formed by welding pieces of transparent plastics material to one face of the belt. Another way of supporting the originals is for them to be electrostatically tacked to a transparent belt or held between a pair of transparent belts.

Where the photosensitive surface and the original are to be moved synchronously during the exposure step, the photosensitive surface is generally on a drum, belt or like support in which case the original belt is preferably driven by a drive taken from the drum or the like.

Using an endless belt as described above, the number of originals which can be accommodated is limited by the space available for the belt run. The same space will usually be able to accommodate a much longer belt which passes between supply and take-up rolls.

From another aspect, the invention consists in a photocopying machine including an original illumination station, an original handling apparatus comprising a belt adapted to support a plurality of originals with both surfaces thereof exposed, a half twist in said belt spaced from the original illumination station, means for driving the belt past the original illumination station alternately in opposite directions, and means for translating the twist along the belt from one side of the illumination station to the other.

In order that the invention mav be more readily understood, reference will now be made to the accompanying drawings, in which: - Figure 1 is a schematic side elevation of one embodiment of electrophotographic copying machine according to this invention, Figure 2 is a partial top view of a belt similar to that seen in Figure 1, and Figure 3 illustrates a modification.

Referring to the drawings, the general operation of an electrostatographic machine as illustrated will first be described with reference to Figure 1. A moving photoconductive plate, in this instance having an endless surface constituting the periphery of a drum 1, is first uniformly charged at a charing station 2 and the surface then exposed at an exposure station to a light pattern of the image sought to be reproduced thereby to discharge the charge in the areas where light strikes the plate surface. The undischarged areas of the surface thus form an electrostatic charge pattern in conformity with the configuration of the original image pattern. In the embodiment illustrated the original is driven past the exposure station and illuminated by a lamp 4, the drum surface being exposed thereto through a slit by an optical system represented by a lens 5, whereby a flowing image of the original is formed on the moving drum.

The electrostatic latent image is then developed into visible form by the development system 6 which in this embodiment is a liquid development system employing the technques described in British Patent Specification No. 880597 and schematically represented by an applicator roll of such a system. As described in that specification the liquid developer is applied to the photoreceptor by an applicator in the form of a roll having a peripheral surface comprising lands and valleys such that the liquid developer is contained in the valleys out of contact with the photoreceptor, whilst the surfaces of the lands are in contact with the photoreceptor. In such an arrangement, the liquid developer is attracted from the valleys to the electrostatic latent image in image configuration. The illustrated embodiment exemplifies a typical example of such an arrangement in which the applicator is a rigid cylindrical member having on its surface a pattern of grooves and ridges which comprise the lands and valleys respectively, the liquid developer being maintained in the valleys below the surface of the lands.

As the photoreceptor surface bearing the electrostatic latent image and the applicator are brought into moving contact the liquid developer is drawn to the photoreceptor from the valleys of the applicator roll by the charges which form the electrostatic latent image.

Subject to the development operation the now visible image is transferred from the plate to a sheet of final support material 7, such as paper or the like, thereby to form a permanent print, at a transfer station schematically illustrated by a transfer roll 8. The paper is suitably supplied using known techniques from a supply tray 9.

Following transfer, the drum surface is cleaned of residual developer material suitably by means of a blade 10 arranged at a leading angle to the direction of drum rotation. The drum surface is finally illuminated at 11 to remove any remaining charge therefrom.

Referring to Figues 1 and 2, the original handling apparatus of this invention comprises an endless belt 20, formed by seaming together the ends of a strip in a moebius loop. A plurality of axially spaced original pockets 21 are provided along its length on one face. The belt is of transparent plastics material and the pockets are formed by welding sheets of transparent plastics material to the belt along three edges thereof leaving an opening for the insertion and removal of originals to be copied. It will be realised that both faces of the pocket are transparent so that both sides of a duplex original placed therein will be exposed to view. Suitable plastics materials for the belt and pocket forming sheets are polyvinylchloride and a polyester such as Mylar (Trade Mark). The belt extends over two pairs of sprockets 22 mounted on axles 23, 24 and the belt has sprocket holes 19 accurately punched or otherwise formed along the side edges thereof. In order to ensure that the movement of the belt 20 is synchronised with that of the drum 1, the belt is driven directly from the drum. To this end, the axle 24 carries at one end a pulley 25 driven via a belt 26 from a pulley 27 on the shaft of the drum 1.

The pulleys 25, 27 are relatively adjustable for loading and unloading of the belt to permit the use of belts having differing numbers and/or sizes of pockets. Or cassette loading of different belts may be employed. Such a cassette may comprise a housing or frame supporting a belt mounted on the sprockets 22.

In operation, the pages of a document to be copied are loaded into the pockets 21 either before loading of the belt into the apparatus or whilst it is in position on the sprockets 22 (in which latter event means should be provided to disengage the sprockets from the drive thereby to allow them to freewheel during loading of the originals).

The copying machine is then started up. It will be understood that a moebius strip has a single continuous surface. Thus as the belt is driven, duplex originals placed in the pockets will have the opposite sides thereof fed past the illumination station 4 of the copier in sequence. For example, in the case of a belt carrying four duplex originals, the eight sides will be copied in the sequence 1, 3, 5, 7, 2, 4, 6, 8, this sequence being repeated as many times as desired. In order to produce simplex sets, the first four sheets (1, 3, 5, 7) of each set must be held in a buffer pending the next four sheets (2, 4, 6, 8) which must be interleaved therewith.

Fully precollated simplex to simplex copying may be achieved by arranging that the originals carry the information in the following order (in the case for example of an eight page document): pocket 1-sides 1, 5; pocket 2-sides 2, 6; pocket 3-sides 3, 7 and pocket asides 4, 8.

The apparatus illustrated here is however particularly suited to duplex-to-duplex copy ing. For this purpose a buffer tray 30 is required for the copy sheets in addition to an output tray 31. The front side of each original is copied first using copy sheets 7 from the supply tray 9 and the copies 7 fed into the buffer tray 30 from which they are supplied during copying of the reverse sides of the originals. Following transfer of the reverse side information the copies are fed into output tray 31. In order to maintain the proper sequence, the copies should be fed from the buffer tray by a bottom feeder, examples of which are well known in the art, represented by roller 32. In addition to inverting the copy sheet as shown it may be necessary to turn it through 1800 on its own plane to ensure the proper or desired relationship of the information on the opposite sides thereof.

It will be noted that the documents may be arranged lengthwise (Fig. 1) or crosswise (Fig. 2) of the belt. Also, the belt may be supported at the moebius twist by one or more rollers 33. Additional guide rollers may be provided intermediate the rollers shown.

Although a specific embodiment has been described, it will be understood that various modifications may be made without departting from the scope of the invention as defined in the appended claims. Thus, the originals to be copied may be supported by the belt in other ways than described. For example, the originals may be electrostatically tacked to a transparent plastics belt.

Or the belt may comprise a pair of transparent strips between which the originals are sandwiched.

Instead of being exposed to the originals through an optical system as described above, the photosensitive surface may be exposed directly by sorcalled contact exposure in which the original is fed between a stationary illumination source and the moving photosensitive surface, the original being moved in synchronism with the surface and face down to the surface and an image of the information on the original being obtained by illumination through the sheet or the like on which it is supported.

In a modification as shown in Figure 3 a greater original handling capacity is achieved by an original supporting belt 20 which is driven between supply and take-up spools 41, 42. The belt, which may take any of the forms described above, is provided with a half twist between roller pairs 43, 44. These roller pairs are movable as a unit from one side to the other of the optical path 5a to invert the belt at the illumination station 4. In operation the belt is driven in one direction, with the twist in the full line position shown, to copy the front sides of the originals. The twist is then moved to the dotted line position shown and the belt driven in the opposite direction to copy the reverse sides of the originals.

In a further modification illustrated in Figure 4 in which an original supporting belt 20 is driven between supply 41 and take-up 42 spools as in Figure 3, the position of the twist is fixed (stationary twist) and two separate optical systems 5 are provided, at opposite sides of the twist. These systems include mirrors 51 and a common triangular mirror 52, the lamps 4 being independently operable so that only one image is projected at a time. Instead of triangular mirror 52, a pivot mirror may be provided. It will be realised that with this arrangement both sides of the belt may be scanned without moving the twist.

It is to be understood that in the practice of this invention duplex originals may be provided by arranging simplex originals back-to-back.

WHAT WE CLAIM IS: - 1. In a photocopying machine including an original illumination station, an original handling apparatus comprising an endless belt adapted to support a plurality of originals with both surfaces thereof exposed to view, a moebius twist in said belt spaced along the belt path from the original illumination station, and means for driving the belt past the original illumination station.

2. In a photocopying machine including an original illumination station, an original handling apparatus comprising a belt adapted to support a plurality of originals with both surfaces thereof exposed, a half twist in said belt spaced along the belt path from the original illumination station, means for driving the belt past the original illumination station alternately in opposite directlons, and means for translating the twist along the belt from one side of the illumination station to the other.

3. A machine as claimed in Claim 1 or 2 in which the belt has a plurality of spaced original receiving transparent pockets.

4. A machine as claimed in Claim 3 in which the belt is of transparent plastics material and the pockets are formed by welding pieces of transparent plastics material to one face of the belt.

5. A machine as claimed in Claim 1 or 2 in which the belt is transparent and originals are electrostatically tacked thereto.

6. A machine as claimed in any preceding claim in which the drive means includes sprockets engaging holes punched or other wise formed along the edges of the belt.

7. A machine as claimed in any preceding claim in which the belt is replaceably mounted.

8. A machine as claimed in Claim 7 in which the belt is supported in a cassette.

9. An electrophotographic copying machine constructed, arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. is then moved to the dotted line position shown and the belt driven in the opposite direction to copy the reverse sides of the originals. In a further modification illustrated in Figure 4 in which an original supporting belt 20 is driven between supply 41 and take-up 42 spools as in Figure 3, the position of the twist is fixed (stationary twist) and two separate optical systems 5 are provided, at opposite sides of the twist. These systems include mirrors 51 and a common triangular mirror 52, the lamps 4 being independently operable so that only one image is projected at a time. Instead of triangular mirror 52, a pivot mirror may be provided. It will be realised that with this arrangement both sides of the belt may be scanned without moving the twist. It is to be understood that in the practice of this invention duplex originals may be provided by arranging simplex originals back-to-back. WHAT WE CLAIM IS: -

1. In a photocopying machine including an original illumination station, an original handling apparatus comprising an endless belt adapted to support a plurality of originals with both surfaces thereof exposed to view, a moebius twist in said belt spaced along the belt path from the original illumination station, and means for driving the belt past the original illumination station.