GB2220815A - Combined duplicator and copier apparatus - Google Patents

Abstract

A combined duplicating and copying apparatus for either duplicating a large number (710) of copies or copying a smaller number of copies from an original includes a digital imaging unit 14 for generating an image representative digital signal which controls the operation of the thermal heads of a master producing unit 24 for cutting masters for printing, or of a transfer copying unit 26 for producing direct copies of the original. The master producing unit thermally cuts masters from a master sheet and then transfers the cut master to a printing drum 39 or drums (Fig. 2) for duplication onto sheets 60. Alternatively the copying unit 26 may be used to produce direct copies by melting toner, supplied on a ribbon, which adheres to the copy paper. Copying is also envisaged using dot matrix, ink jet and toner vapourisation printing. A controller 15 may automatically select duplicating or copying modes according to the number of copies requested through keyboard 19. An auxiliary input is also provided for receiving digital image signals from auxiliary sources such as facsimile machines or computers. <IMAGE>

Description

"COMBINED DUPLICATOR AND COPIER APPARATUS" The present invention relates to a combined duplicator and copier apparatus, and in particular to an apparatus by which copies of an original may be obtained either by duplication to obtain a relatively large number of copies or by copying when a relatively small number of copies is required in a cost effective manner.

Prior art duplicators or copiers have generally been designed to achieve particular parameters of efficiency and cost effectiveness for the single purpose for which they were designed. This has not enabled the two different devices conveniently to be combined together to form a single combined copier and duplicator. The present invention overcomes this difficulty by having apparatus in which a plurality of components are used in either the copying or duplicating processes while keeping a minimum of components which are required solely to be used for only one of the two processes.

According to the present invention there is provided, a combined duplicating and copying apparatus operable selectively in a copying mode or a duplicating mode for copying an original, said apparatus including a digital imaging unit for converting an image on the original into a digital signal; a master producing unit responsive to said signal for creating a master copy of the original for duplication; a printing drum for duplication of the original; a transfer copying unit responsive to said signal for creating copies of the original; a paper feeder for supplying copy paper alternatively to said printing drum or to said transfer copying unit to receive an image of the original; a transport unit for transporting the copy to a receiving tray; and control means for controlling the mode of operation of said apparatus such that when in the duplicating mode the transfer copying unit is inoperable andthe paper feeder is operable to deliver copy paper direct to the printing drum, and when in the copying mode the master producing unit and printing drum are inoperable and the paper feeder is operable to deliver copy paper to the transfer copy unit to receive an image thereat.

Since the apparatus is based on a digital representation of the information on the original it can be used to produce copies from data from outputs of other common office machines such as personal computers and facsimile machines through a digital signal receiving input bypassing the digital imaging unit.

The apparatus of the present invention provides an efficient and cost effective system for either copying or duplicating an original. Typically the copying portion of the apparatus is suited to producing up to ten copies of the original while the duplicating portion of the apparatus is adapted for producing larger numbers of copies and is capable of printing a run of copies of a single original at a faster rate, typically 40 to 120 copies per minute, than the copying portion.

The following description is given merely by way of example with reference to the accompanying drawings, in which; Figure 1 is a schematic view of the principal components of the apparatus; and Figure 2 is a schematic view similar to Figure X but showing an alternative printing arrangement.

Referring to Figure 1 there is shown a digital imaging unit 14 provided with an original reading position.

A double set of rollers 12 are provided for accurately moving the original over the reading or scanning position 10. The digital imaging unit 14 is adapted to translate information on the original line-by-line into a digital signal and comprises an exposure lamp 16, a mirror 18, a lens 20 and a charge coupled device 22. The charge coupled device preferably has at least 12 elements per mm to give adequate resolution and can either be of discrete form or a linear array of elements of the same width as the original to be copied or duplicated and includes a controller and an automatic thresholding device.

A thermal master producing unit 24 and a thermal transfer copying unit 26 are provided alternatively to receive the digital output signal from the digital imaging unit via a control unit 15. The control unit 15 typically includes a display 17 showing the number of copies to be produced and control input keys 19.

The master producing unit 2 includes means for supplying master material from a master material supply roll 28 to a stencil cutting thermal head 30 which includes a drive and support roller 32. A cutter 34 is provided for severing the cut master at the required length. Exit drive rollers 36 are also provided for driving the cut master out of the master producing unit 24. The thermal head 30 is responsive to the signal from the output of the digital imaging unit 14.

A printing drum 38 comprises a generally cylindrical hollow unit having an external surface made up of a set of foil screens adapted for receiving ink from an ink supply 42 inside the hollow cylindrical unit 39. A releasable clamp 40 is mounted at the surface of the printing drum 38 for gripping the leading end of a master sheet fed to the drum and a movable copy sheet stripping blade 44 is provided adjacent to the surface of the printing drum 38. A master storage unit 47 is positioned in the vicinity of the blade 44 for receiving discharged masters stripped from the printing drum 38 after printing and fed into the storage unit by means of feed belts 48.

The thermal transfer copying unit 26 comprises means for supplying toner coated ribbon 54 from a ribbon supply 58 to a copying point where it is held against a thermal head 50 by means of a roller 52. A takeup spool 56 is provided for receiving used ribbon. The thermal head 50 is adapted td receive the digital signal output from the digital imaging unit 14 via controller 15.

The apparatus further includes a paper supply 60 from which copy paper is supplied either via path 70 to the thermal transfer copying unit 26 or via path 68 to the printing drum 38. A pair of drive rollers 72 are provided for driving copy paper over pressure roller 46 which is movable between a lower, idle, position as shown in the drawing, or a working position at which the pressure roller holds a copy paper to be printed in pressure contact with the printing drum 38. A vacuum transport unit 62 is shown for transferring the copy paper to receiving trays 64 or 66 although other feed means may be used as convenient.

The operation of the apparatus is controlled by means of controller 15. The operator selects the type and number of copies required by means of input keys 19, the display unit 17 giving an indication of the operator's selection. The controller 17 can be set to a manual mode in which the operator can select the mode of operation of the apparatus. Alternatively, the control unit 15 can be used in the automatic mode whereby it automatically selects the mode of operation of the apparatus, the selection being based on the number of copies required, and whether the auxiliary input 80 has been selected. The first step in the production of a copy of the original selected by the controller is the reading of the information on the original by means of the digital imaging unit 14.

The image on an original is read by moving the original over the scanning point 10 by means of drive rollers 12 on activation of the exposure lamp 16. The reflection of the image is reflected off mirror 18 through lens 20 onto the charge coupled device 22 which produces a digital signal corresponding to each read line and preferably consists of a chip having 4000 pixels for receiving the image.

Modulation transfer function errors caused by the lens 20 or the charge coupled device 22 may be compensated for by the provision of a thresholding device specially adapted to compensate for originals of differing colours, picture halftones and input data of different formats. The charge coupled device controller is adapted to control the chip and to modify the signal output from the charge coupled device 22. In particular, the signal can be edited, parts thereof can be deleted and characteristics such as shading and colour can be added to the image to be reproduced. A memory may be provided in the controller for storing the image data for later reproduction such as pre-scanned standard forms.

The digital output from the charge coupled device 22 is then sent either to the thermal head 30 of the master producing unit 24, or to the thermal head 50 of the transfer copying unit 26, unless the auxiliary input 80 is in use.

Each thermal head 30,50 preferably has a resolution of at least 12 pixels per mm. In the duplicating mode the thermal head 30 of the master producing unit 24 receives the digital signal from the charge coupled device 22 and thermally cuts a stencil master out of master sheet supplied from supply roll 28 and driven across thermal head 30 by means of the drive roller 32. The master is then moved to be gripped by the clamp 40 of the printing drum 38 by means of the dual set of drive rollers 36, the master being cut off to the required length by means of knife 34. When precut master sheets are supplied instead of a continuous roll, the roll feeder 28 and the knife 34 are kept idle.

The master sheet suitably may comprise a basic tissue layer laminated to a very thin thermosensitive polyester film. The laterally stressed film ruptures in response to heat generated by the thermal head 30 to leave an appropriate perforation.

The imaged master is secured onto the printing drum by means of clamp 40 and is then automatically wrapped round the printing drum prior to the printing operation. Once the imaged master is positioned onto the printing drum 38 copy paper is fed from the paper supply 60 via the copy paper supply path 68 through drive rollers 72. The copy paper is kept in pressure contact on the surface 39 of the printing drum by means of pressure roller 46. Ink is supplied through the foil screens of the surface 39 of the printing drum 38 from an ink supply 42. The printed sheets of copy paper are then transferred to the receiving tray 66 by means of the vacuum transport unit 62. Any convenient form of transporting means may be used instead of the vacuum transport unit 62.Once the required number of copies of the original have been produced the master is discharged from the printing drum by means of stripping means, not shown, which are moved into close proximity to the edge of the printing drum to to peel of the master. The master is then transferred to a master storage unit by means of belts 48 for storage and subsequent disposal.

Copies can be produced in any desired ink colour merely be changing the printing drum 38 for one having a reservoir 42 of appropriately coloured ink.

The master can alternatively be removed by means of a second roller, not shown.

This mode of operation is preferably selected when more than 10 copies of the original are required. During this mode of operation the transfer copying unit 26 is idle.

When the copying mode is selected, the thermal head 50 of the transfer copying unit 26 receives the digital signal from either the charge coupled device 22 or from the input 80 through the controller 15. The image on the original is copied directly onto the copy paper by supplying the copy paper via path 70 to the copying point of thermal head 50. The thermal head 50 melts the toner on the toner coated ribbon 54 which is held against the copying point of thermal head 50 by means of the drive roller 52. The copy paper is then moved away from the copying point by means of the drive rollers 72 and is transferred over the pressure roller 46, which in this mode of operation is in the lower idle position, via transport unit 62 to the receiving tray 64. During the copying operation the toner ribbon 54 is supplied continuously from the supply roll 58 and taken up on takeup spool 56.In this mode of operation the master producing unit 24 and the printing drum 38 are idle.

Copying mode is preferably selected when 10 copies or less of the original are required.

The auxiliary input 80 is adapted through an appropriate interface to receive digital image signals from auxiliary sources such as facsimile machines or computers.

The controller 15 detects whether this auxiliary input is in use, and if this is so disables the output from the digital imaging unit 14 and supplies the auxiliary digital image signal to either the thermal head 30 or the thermal head 50 depending on the mode of operation of the apparatus. The controller 15 preferably disables the digital imaging unit 14 only when this unit is not in use so as to allow the apparatus to complete one operation before starting the next.

The image of the original can be enlarged or reduced either mechanically, by means of movement of the lens 20, or digitally by electronic manipulation of the digital data output from the charge coupled device 22. Control of any enlargement or reduction of the original will be carried out automatically by the controller.

While the printing drum illustrated is shown in Figure 1 as a stencil duplicator type printer, it will be appreciated that with suitable adjustments other types of printing operations, for example offset printing, may be used. Similarly while a toner melting ribbon unit has been shown for the copier unit alternative image producing means may be used as convenient, for example a pressure printing dot-matrix type head, an ink jet printer or a thermal printer where toner is vapourised and condensed onto the paper instead of being melted. Figure 2 is similar to Figure 1 except that instead of a single drum type printing device it shows the use of a twin drum stencil duplicator arrangement in which a perforated stencil carrier 391 is trained around two drums 381 and 3811 with the clamp 40 being carried by the stencil carrier. The ink is supplied at 421 to the exterior of the drum 381 so as subsequently to pass through the carrier 391 and the perforations on a stencil carried thereon.

Claims (10)

1. A combined duplicating and copying apparatus operable selectively in a copying mode or a duplicating mode for copying an original, said apparatus including a digital imaging unit for converting an image on the original into a digital signal; a master producing unit responsive to said signal for creating a master copy of the original for duplication; a printing drum for duplication of the original; a transfer copying unit responsive to said signal for creating copies of the original; a paper feeder for supplying copy paper alternatively to said printing drum or to said transfer copying unit to receive an image of the original; a transport unit for transporting the copy to a receiving tray; and control means for controlling the mode of operation of said apparatus such that when in the duplicating mode the transfer copying unit is inoperable and the paper feeder is operable to deliver copy paper direct to the printing drum, and when in the copying mode the master producing unit and printing drum are inoperable and the paper feeder is operable to deliver copy paper to the transfer copy unit to receive an image thereat.

2. An apparatus according to claim 1, wherein a master storage unit is provided for receiving and storing master copies discharged from the printing drum.

3. An apparatus according to claim 1 or 2, wherein the master unit comprises master cutting means and means for supplying master sheet material to said cutting means, said master cutting means being adapted to cut a stencil in said master sheet material responsive to said digital signal.

4. An apparatus according to claim 3, wherein the printing drum is a stencil duplicator type drum or drums provided with means for securing said master thereto, there being provided an ink reservoir and means for transferring ink from said reservoir to said master from the side of the master closest to the drum.

5. An apparatus according to claim 3 or 4, wherein the master cutting means comprises a thermal head controlled electrically to cut said master into stencil form responsive to said digital signal.

6. An apparatus according to any preceding claim, wherein said master sheet severing means are provided for severing individual master sheets from a continuous feed of master sheet material.

7. An apparatus according to any preceding claim, wherein said transfer copying unit includes means for supplying a toner coated ribbon to a thermal head responsive to said digital signal for melting toner from the ribbon onto copy paper during use of the copying unit.

8. An apparatus according to any preceding claim, wherein an auxiliary input is provided for receiving digital image data from an auxiliary source, said auxiliary input being selectively connectable to said master producing unit or said transfer copying unit for producing copies by duplication or copying of the image data received.

9. An apparatus according to any preceding claim, wherein said control means includes selection means automatically to select the duplicating or copying mode of said apparatus in dependence upon the number of copies of the original selected as being required.

10. A combined duplicating and copying apparatus constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.