GB2282567A - Multi-ribbon printer - Google Patents

Abstract

A non-impact printer has at least one ribbon with panels such as yellow, magenta and cyan and a black ribbon. The printing may be by thermal transfer or dye diffusion and may provide precoat, overcoat, and the like, or combinations thereof, and may also include a direct energy printing assembly. Two or more energy sources provide energy for those printing processes and are independently selectable for use with a selected one or more of such ribbons. The device provides repeated printing onto a substrate without moving the latter. Means are also provided for identifying and utilizing unused transfer panels or portions of panels so as to minimize wastage of ribbon; for transverse substrate movements which permit printing images that are larger than the print head, and for double precision (half-line or half-dot) printing in both longitudinal and transverse directions.

Description

Printing Apparatus This invention relates to an image forming apparatus or nonimpact printer that uses an ink or dye ribbon and a form of energy to cause the transfer of a selected por-tion of ink or dye to a substrate to form an image, and particularly to such printers that are capable, e.g., of carrying out both thermal transfer ano dye diffusion printing.

Specifically, the invention relates to a printer in which separate print heads, ribbons and image transfer mechanisms are provided to permit multiple image transfers onto a substrate that remains held throughout to help ensure accurate image registration.

In thermal transfer printing, an ink- or dye-bearing ribbon is pressed against a substrate between the thermal print head and a platen.

The substrate can be ordinary or specially coated paper, or also plastic film, acetate and the like. Resistor elements in the print head are selectively subjected to a heating current to cause the transfer of ink or dye from the ribbon to the substrate in a desired pattern. In the analogous electroresistive printing process, the print head incorporates needle-like electrodes that are selectively brought into contact with an electroresistive ribbon layer to cause an electrical current to pass therethrough, through an underlying electrically conductive layer, and thence back to a return electrode placed against the electroresistive layer.Variously colored heat sensitive ink layers are disposed on the side of the conductive layer opposite the electro-resistive layer, and the heat generated within the electroresistive layer passes through the conductive layer to cause softening or melting and thus transfer of the ink in the ink layer to the substrate in a desired pattern. In dye diffusion printing, the diffusion or sublimation of dye from the ribbon to the substrate is employed instead of melting ink.There also exist direct energy processes, and other image transfer mechanisms employ combinations of chromogenic materials and encapsulated radiation curable compositions, combinations of a developer and a photosensitive microencapsulated material, materials subject to transfer when acted upon by light, and materials in which a combination of light and heat will bring about changes in such physical parameters of said materials as viscosity or various softening, melting and glass transition temperatures.

For black printing, a single black ink or dye panel can be used, and a single ribbon might include a multiplicity of black panels, each or the same size (e.g., letter, legal size, A-4 or A-5, etc.) as the substrate onto which the image is to be transferred. For color printing, generally three separate color panels in the colors yellow, magenta, and cyan are used, and these panels will typically be arranged in repetitive units along the ribbon. A full color image is formed from the three primary colors by printing one over the other, typically in the order yellow, magenta and cyan.

The three colors can also be superimposed to produce a black image, but such an image will not be of the same quality as is produced using a single black ink or dye. To use three color panels to produce a black image is also wasteful of color panels, and significantly increases the time required for the image transter. To obtain the higher quality black image available from a black riDbon has hitherto required rep:acement of the three--coior ribbon w2th black ribbon, hence to avoid such repetitive ribbon changing, ribbons have been devised that include black panels in addition to the three color panels.

One disadvantage of the foregoing procedure, however, is that of needing to traverse through the ribbon in order to arrive at a black ink panel, move back again to carry out color printing, then go back to the black panel, or to another panel type, and so on. Such a pro-cess is wasteful of time and can ultimately be damaging to the ribbon. Moreover, the relative amounts of full color and black or other printing (e.g., thermal transfer and dye diffusion) required may not coincide with the relative numbers of different panel colors or types on the ribbon, so that some portions of the ribbon may become wasted.

Another disadvantage of the "combination ribbon" approach is that thermal transfer and dye diffusion printing a e generally employed for different purposes. For example, conventional thermal transfer processes, while less restrictive than dye diffusion in terms of the nature of the substrate, do not produce the true continuous tone images that can be obtained using dye diffusion, and it would be difficult to estimate in advance, in developing a ribbon to be used for both of those processes, the relative numbers of ink and dye panels to include on the ribbon. More recent thermal transfer techniques that incorporate variable dot size provide higher quality, but require special ribbons and print heads.It is preferable, therefore, to provide a printer in which the thermal transfer (conventional or more recent) and dye diffusion processes are carried out using different ribbons, each designed for use in just one of those two processes. Of course, if electroresistive printing is also to be employed, that process must likewise have a ribbon therefor. It may also be desired, of course, to provide means for direct energy printing in which no ribbon is employed.

One solution of the foregoing problem has been to employ two printers: one having a three-color ribbon for full color printing, and other a totally black ink ribbon for printing in black. However, that process introduces extra expense, and also requires additional desk space.

Moreover, for images that require black printing along with full color printing, to obtain the higher quality black image from the black ink printer it becomes necessary to transfer the substrate onto which the image is to be placed from one printer to the other, and it may be difficult or impossible to obtain the same positioning of the substrate in the one printer as the other, so that the image transferred in the second printing will appear where desired relative to the first image. The alternative procedure of using just one printer but changing ribbons for each kind of printing process, while saving of expense and desk space, introduces even greater operator inconvenience.

In the copier art, US-A-4 783 681 describes a system that includes a plurality of copier units, each of which will record an image on a separate recording material wrien used alone, but when the units are coupled together a single material can receive a iirst image from a first copier unit and then be transported to a second unit to receive a second, overlaid image, and so on. The plurality of identical recording units are designed to plug one into the other so that recording material can be passed therebetween, and control of such a sequence of recording units is then carried out from the first unit in the sequence.Registration between successive images is controlled firstly by using sheet discharging means within a sheet transferring unit to place a sheet of image-receiving material into the next unit in the sequence, and secondly by transmitting from the transferring unit to that next receiving unit a timing signal to control the registration rollers of tne latter unit. Although this $cinaka et al.

patent does address the multi-image registration proviem noted avoid, it does not address the transfer or images either by direct energy or ny using a transfer material disposed on a ribbon.

Another type of thermal transfer printer employs a back roller instead of a platen such that the back roller faces against the thermal head with the ink donor sheet or ribbon and the recording sheet or receiving medium pressed therebetween as usual, wherein the back roller is driven by a motor so as to advance both the ribbon and receiving medium. US-A-4 495 507 describes such a device that contains two complete "recording stations," i.e, two separately functioning back rollers, back roller drive motors, thermal heads, and ribbons (on associated supply and takeup rolls) wherein the two ribbons provide two-color printing onto a receiving medium that is made to pass first through one recording station and then through the other.This particular "two-station" design has its own type of registration problem, namely, that any difference in diameter between the two back rollers will cause differences in the rate of advance of the receiving medium in the two cases, thereby introducing a color shift in the transferred image. The '507 patent seeks to resolve that problem by using different roller drive motors so that one motor can compensate for such variations in the rate of medium advance.

In two-station printing, it had also been the practice for the image data for the second station in line to be stored in memory, to be released at a time determined by the distance between printing stations and the rate of movement of the ribbon and substrate. Because of the distance of separation required between the two thermal heads in such a linear design, however, the amount of memory required for such data storage came to be a problem, hence a variant of the '507 device, found in US-A-4 385 302, employs a plurality of thermal head assemblies arranged aroungd a single backing roller.In a linerar, three-station embodiment, synchronization between the image-forming processes is achieved by way of synchronization larks that, along with the first image transfer (e.g. a yellow color transfer), are placed by the first thermal head along one edge of the substrate and are then read by first and second marker sensors associate respectively with second and third thermal head assemblies. In US-A-4 408 212, positional displacement between images in a two- or multiple-head device is avoided by means of a belt that extends around adjacent rollers in contact with the substrate upon which such images are placed so as to eliminate positioning errors arising from any differences in the diameters of such rollers.US-A--4 410 897 describes two separate recording stations of the back roller type that are disposed on opposite sides of the substrate onto which the image is to be transferred so as to permit printing on both sides of the substrate in a single pass.

US-A-4 462 704 sets forth pulse generator means that operate from a single power source for driving a plurality of thermal print heads in the '897 configuration. Similarly, US-A-4 811 036 describes two separate printing means, e.g., conventional thermal print heads using separate platens and printing films (i.e., ribbons), disposed on opposite sides of a continuous strip and controlled in such a way that the longitudinal positioning of the images produced by the two thermal print heads on the opposite sides of the continuous strip are cordinated.

US-A-4 595 303 describes a printing apparatus including two assemblies in which one provides character type elements and the other produces characters using a dot matrix. US-A-4 863 297 describes a thermal printer having three thermal heads, each of which is disposed to transfer ink from a separate colored ribbon. It is not possible from any of these constructions, however, to provide all of the run-damentally different types of printing1 i.e., thermal transfer, dye diffusion, and electroresistive, that may be needed in the more modern printing environment.

US-A-4 815 872 seeks to describe apparatus haviny two print heads and associated ribbons and platens: one print head is used conventionally for multicolor printing, and a second print head for which the associated ribbon contains only transparent ink serves to print a protective layer over the multicolor image. This patent thus does not explicitly address the aforesaid registration problems.

Some of the problems remaining within the foregoing art have been addressed as by making possible the use of various technologies within a single printer by way of "coinbined ribbons" and multiple printing devices.

However, it still remained necessary, in order to carry out those different technologies, to move the substrate from one printing location to another.

That is, in any of the embodiments that nave two different print heads that can be placed individually into coöperation with one and the same ribbon/printing system, there is available within a single such system only a single ribbon. Whatever type of printing may be desired must then hbe provided either (1) by way of panels that are incorporated within that system, or (2) by moving the substrate to a different ribbon/prin;ting location, thereby introducing possible registration errors. iSome of the print head/ribbon combinations that would be required may be limited in scope: if but a single printing location is to be used to avoid registration errors1 the single ribbon associated with that one location may become very spe cialized.What is needed and would be useful, therefore, is a means for conducting in a consistent way various multiple image printing tasks wherein the substrate need not be moved between printing locations, and indeed for reasons of printing speed, wherein more than one printing process can be carried out at the same time. Accuracy of registration between images will thus be limited only by the printing process itself, and not by having been required to move the imagereceiving substrate after having completed one printing task so as to commence another. Although at the expense of providing one or more additional print heads, that capability is provided by the present invention in which multiple ribbons and associated energy sources for image transfer are able to carry out successive printing operations on a substrate that has remained held throughout.

The invention in its several aspects encompasses a wide range of applications, for which the use of particular terminology seems appropriate. When used hereinafter, therefore, unless otherwise indicated the following terms will have the meanings stated: Enerrv Source: A source of a form of energy (heat or light), including a laser, a conventional thermal transfer print head, and the like.

Transfer material: A substance placed on a medium for the purpose of being transferred therefrom to a substrate by the application thereto of one or more forms of energy in order to form an image on the substrate, either directly or indirectly.

Printer: An apparatus that uses an energy source to apply one or more forms of energy either to a transfer material or to a substrate so as Lu LULIII buayo on the substrate, including a printer, a facsimile machine (FAX), the printing portion of a copier, or the printing portion of any other device that functions as stated.

Direct Energy: A method of forming an image in which one or more forms of energy are applied directly to a substrate on which the image is to be formed. The energy elicits some change in the material of the substrate so as to form the image either from that energy alone, or following passage of the substrate through a hot roll process or the like.

Technology: A particular method of transferring an image from a medium to a substrate using one or more forms of energy, including those in which the transfer material comprises thermal transfer ink, dye diffusion dye, electroresistive ink, combinations of chromogenic materials and encapsulated radiation curable compositions, combinations of a developer and a photosensitive microencapsulated material, materials subject to transfer when acted upon by light (including laser light), and materials in which both light and heat bring about changes in at least one of the group of physical parameters of said materials consisting of softening, melting and glass transition temperatures, and of vis cosity.The term also encompasses developing an image by direct energy processes, as well as other methods and materials whether or not presently known or conceived Tele: Variations in method within a particular technology, such as the use of different thermal transfer materials that require different temperatures or the like for transfer to occur.

Class: A subset of transfer materials within a particular technology, e.g., precoat, overcoat and colored ink comprise three classes of thermal transfer materials.

Panel: A single continuous region on a substrate that has had a single class of transfer material, and in a single color (where applicable), applied thereon.

Set: A collection of one or more panels that are contiguous (or nearly so) and fall within a particular class, e.g., a set of yellow, magenta and cyan (y, m, c) coior thermal transfer panels.

Group: A collection ot panels, or sets of panels, that fall within a single technology, e.g., a set of y, m, c panels, a black panel, and one or more panels of precoat or overcoat that all transfer Dy means of a single type of thermal transfer.

The invention employs a drum or a belt and clamp with a platen or grit roll to control the movement of a sheet of imagereceiving substrate.

The drum or platen is operated in cooperation with two or more ribbon/print head systems disposed circumferentially thereabout so as to print successive images on the substrate without removing control thereof. Each of the "print head" systems comprises an energy source and a separately controlled ribbon (or no ribbon, in the case of a direct energy process) for printing in accordance with selected ones of various printing technologies, and over a portion of the printing sequence can operate simultaneously.Position ing of the drum or belt/clamp is monitored by a shaft encoder so as to define the distances between successive lines of image, by which is meant not a line of text but rather a row of dots, wherein the image (text or otherwise) is created from the accumulated effect of many such adjacent and parallel rows of dots (each dot of which is either printed or not, according to the image desired).

Determination of the location of the first printable line rests on sensing the leading edge of the clamp that holds the substrate and imposing a predetermined delay thereafter so that, e.g., successive yellow, magenta and cyan images can be transferred with good registration between those images using one print head/ribbon system and then, e.g., the substrate can be moved to a second print head/ribbon system for adding black text.

The invention also includes an in-line version.

Again, accurate registration between images is accomplished by sensing the edge of a clamp that holds the substrate and thereafter employing a shaft encoder disposed on the apparatus which holds the substrate (either on a drum or a belt/clamp assembly) to define the location of the first printable line and each following line.

In a second aspect of the invention, a transversely moveable ribbon/print head device is provided as one of said ribbon/print head systems so that an "inserted image can be transferred to a substrate at one or more arbitrarily and conveniently selected positions, or a larger image can be formed out of a composite of smaller images that have each been so positioned.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1A shows a side elevation view of a mechanism for holding a sheet of substrate to be printed upon onto a drum; Fig. 1B shows one embodiment of the invention in which two sets of print heads and corresponding ribbons are disposed about the drum of Fig.

lA; Fig. 2 shows another embodiment of the invention having circumferentially disposed print heads, a centrally located platen, and a belt and clamp for moving the substrate; Fig. 3 shows a version of the embodiment of Fig. 2 in which the print heads are disposed along a line; Fig. 4 shows a belt mechanism for providing control or the lateral placement of a ribbon/print head combination relative to a substrate; Fig. 5 shows an alternative gear mechanism for controlling the transverse placement of a ribbon/print head combination relative to a substrates, and Fig. 6 shows an example of placing multiple images at separate locations on a since substrate using the mechanisms of Figs. 4 or 5.

Figure lA shows the use of a drum to control the positioning of a sheet of substrate during printing. Drum system lì is mounted to frame 101 and is structured around drum 102 which is rotatably mounted by shaft 103 to frame 101 through a motor (not shown). (The size of drum 102 is a matter of choice, and depending upon the amount of space available within a particular printer design, may be made sufficiently large to accommodate two sheets of substrate.) At least one sheet of substrate 104 is held onto drum 102 by at least one clamp 106, which is recessed within drum 102 to avoid interference with the printing process but is shown exaggerated in Fig. 1A.Spring-loaded rollers 108, which are rotatably attached to frame 101 and press against drum 102 about the circumference thereof, assist in keeping sheet 104 in place once sheet 10 has been grasped by clamp 106, as also does support roller 11@ wnich is rotatably mounted to frame 101 immediately adjacent drum 1u2 ann just past (to tie lower lert in Fig. 1A) of printing point k. Upon sucn grasping by clamp 10u, drum 102 rotates in the direction of arrow 112 (clockwise in Fig. 1A) te advance sheet .64 forward so as eventually to reach the position wrapped around drum 102 as shown in Fig. 1A. (A gap of approximately 1/2 inch of drum area remains between the eading and trailing edges of sheet 104 when so wrapped around drum 102.) A shaft encoder 114 monitors the forward rotation of drum 102 so as to control the printing of successive lines of image at predetermined distances one from the other. As sheet 104 is being advanced past point A, printing occurs as described with reference to Fig. 1B below.

Drum system 100 further comprises first and second substrate guides 116, 118 which serve to guide sheet 104 up to and away from drum 102, respectively. Drum 102 is positioned such that clamp 106 encounters a sheet 104 as the sheet 104 is advanced through first substrate guide 116, and clamp 106 grasps sheet 104. Thereafter, as drum 102 is rotated, a sensor (not shown) detects the presence of the leading edge of clamp 106 that is holding sheet 104 as stated so that printing can commence. The system is instructed to define the first printable line after a predetermined amount of rotation of drum 102 following the sensing of the edge of clamp 106.Thereafter, so as not to waste ribbon, if the first print line actually to be used happens to be the 901st line, then the print head of Fig. 1B noted below is moved forward for printing as perhaps the 875th line is counted.

After printing has been completed, release guide 120, which is rotatably attached to frame 101 near to drum 102 and on the same side thereof as is first substrate guide 116, is rotated under the trailing edge of sheet 104 and drum 102 is then rotated in the direction opposite that of arrow 112 (i.e., counterclockwise in Fig. 1) so as to remove sheet i04 therefrom (i.e., to move sheet 104 in the direction opposite that of arrow 122). As clamp 106 approaches first release guide 120, sheet 104 is released from clamp 106.Sheet 104, which at this time is mainly disposed within first substrate guide 116, is then urged forward through second substrate guide 118 by drum 102 and support roller 110, and is further urged forward by drive rollers 124, which are rotatably mounted to frame 101 and include a drive motor (not shown), for exit from the printer in the direction of arrow 122.

Drum system 100 provides an aåvanWage over the mechanism of Tanaka et al. ('681), in that once printing has begun within drum system 100, the substrate is not removed therefrom. That is, if a sheet 104 is initially printed upon using a yellow panel, drum 102 is further rotated until the edge of clamp 106 is again sensed, and a second printing te.g. using a magenta panel) is similarly commenced after again defining the first printable line by a predetermined degree of rotation of drum 102. This process can of course be followed by a third or fourth printing, etc., as desired and to the extent to which the ribbon incorporates additional panel types for such purposes.In each case, to avoid damage thereto from collision with clamp 106, the print head is moved away from drum 102 during any process that brings clamp i06 near thereto.

Upon completion of printing using a single ribbon/print head system, sheet 104 need not be removed trom drum i02 for subsequent printing by another ribbon/print head system. As shown in Fig. 1B, more than one ribbon/print head system can be given access to a sheet 104 as the same was initially disposed on drum 102, so that no registration errors will be introduced in moving from one ribbon/print head system to the other. The second printing (or third, etc., in the event that the printer has more than two ribbon/print head systems) likewise commences by sensing the leading edge of clamp 106, in ths case (as noted below) by a sensor that is disposed near to the second (or third, etc.) ribbon/print head system.

Counting by means of the shaft encoder is thereupon comnenced to define the first and subsequent printable lines for the particular printing. (Since the displacement of each particular sensor from each respective ribbon/print head system may vary, tne dccual encoder count that defines the first printable line may not be tne same in each of the two or more ribbon/print head systems, but that count is nevertheless fixed and determinable as to each one.) The apparatus of Fig. 1B is thus distinguishable, in that the ribbon/print head systems of Fig. 1B are disposed on the outer periphery of the printer and advance 'inwardly,' i.e. the print head is moved towards the center of the printer to contact the ribbon and carry out the printing process.It is that conceptual change in structure that permits a sheet of substrate to be grasped and held but once, either by a drum or a belt/ clamp, but then to be accessed by different print heads.

More specifically, Fig. 1B shows two ribbon/print head systems disposed about drum 102. A first ribbon/ print head system 126 includes first supply roll 128, which is rotatably mounted to frame 101 by shaft 129 and which dispenses first ribbon 130 onto first takeup roll 132, which is also rotatably mounted to frame 101 by shaft 133. Disposed between first supply roll 128 and first takeup roll 132 is first print head 134, which is electronically operated and driven forward for printing purposes by a motor (not shown) in the usual fashion. In the structure of drum system 100, first print head 134 is driven "inwardly" towards drum 102 for printing as previously stated.It may be noted that while ribbon 130 is disposed on first supply roll 128 with the "printing side" thereof facing inwardly, ribbon 130 is taken up by first takeup roll 132 so that the printing side faces outwardly. Such an arrangement is a matter of choice, except that by such a disposition it may become easier, when installing a new ribbon, to note which of the two rolls (128, 132) is to be placed on which shaft (129, 133).

Drum system 100 further comprises second print head system 136, which is disposed at a differenL location about drum 102 than is first print head system 126, and includes second supply roll 138 which is rotatably mounted to frame 101 by shaft 139, which dispenses second ribbon 140 onto second takeup roll 142, and which is slalso rotatabley mounted to frame 101 by shaft 143. As in first print head system 126, second ribbon 140 is disposed on its second supply roll 138 with the print side down, but is taken up by second takeup roll 142 with the print side facing outwardly. Disposed between second supply roll 138 and scond takeup roll 142 is second print head 144, which may be of the same or of a different type than is first print nead l-.

From the structure shown in Fig. 1B, it is clear that by repeated rotation of drum 102, successive printings on substrate 104 can be carried out by either or both of first and second print heads 134, 144. Of course, in thais and the following embodiments, which print head is 'first' and which is 'second' is arbitrary: the user has the choice of which printing task is to be carried out by which print head, as determined by the nature of the ribbons and print heads installed. indeed, such ribbon and print head selection and subsequent control can be carried out automatically by use of a programmed printer controller wnicn senses the ribbon type, the disposition of precoat, color or blacK panels, etc., ln suzil radons, anu indeed identities unused ribbon portions.

In rotating in the direction of arrow 112, drum 102 Wi ii transport clamp 106 (shown in Fig. iAj and hence substrate 104 entirely past both first print head 134 and second print head 144, and also past first and second ribbons 130, 140 associated therewith. For example, first ribbon 130 may include a repeating series of yellow, magenta and black panels of the thermal transfer type, so that to carry out the first image transfer (e.g., from the yellow panel), both first ribbon 130 and substrate 104 are advanced past first print head 134, preferably at the same speed during printing. Upon completion of that image transfer, drum 102 is further rotated until clamp 106 again approaches first print head 134, while at the same time first ribbon 130 is advanced to the next desired (e.g., magenta) color panel and the process is repeated as desired.

Upon completion of the desired printing using first ribbon 134, drum 102 rotates further to the position at which clamp 106 is coming near to second print head 144.

Second ribbon 140 may comprise, e.g., a continuous black panel for printing text over a full color image, in which case such printing may be accomplished during a single pass of substrate 104 past second print head 144. It may be noted that in Fig. 1B, first supply roll 128 is depicted as being "smaller" than first takeup roll 132, i.e., first takeup roll 132 has in fact taken up more than one half of first ribbon 130, while on the other hand second supply roll 138 is shown as being "larger" than second takeup roll 142, meaning that the latter has taken up less than one half of second ribbon 140.It is intended to emphasize by that depiction that first and second print head systems 126, 136 do indeed function independently, except insofar as substrate 104 must be in the required positions for printing from both of first and second print head systems 126, 136, as controlled respectively by a count derived from shaft encoder 114 of Fig. 1A.Thus, print data might for example be transmitted to second print head 144 after some fixed rotation of drum 102 as indicated by shaft encoder 114 following detection of clamp 106, such as that corresponding to a predetermined

of circumference on the substrate surface. (For particular tasks, and except insofar as some inks or dyes may require some time for drying or otherwise equilibrating before being disturbed, nothing prevents printing from first and second print head systems 126, 136 at the same time, by proper correlation in the print controller of instructions to transmit print data thereto as determined by particular readings of shaft encoder 114.) Upon completion of the desired printing at both such locations- -or at three or more locations or a single location, depending on the number of print head/ribbon systems in a particular embodiment of the invention and on the nature of the printing task at hand--substrate 104 can be removed from drum 102 as previously described.

The use of a drum (and associated clamp to hold the substrate) with multiple print head/ribbon systems, which allows accurate registration between images, as for example between successive ye .ow, magenta and cyan images that are transferred by separate print heads, has not previously been shown in the art and is thus novel to the present invention.

The term "print head" is of course used in a generic sense: what is specifically required here is merely an energy source (and associated application means) of one of the types previously defined for conducting printing of a type appropriate to the nature of the ribbon being used. (Indeed, if any portion of substrate 104 is adapted to receive an image by a direct energy process, one or the other of first and second print heads 134, 144 may be a direct energy source, in which case the ribbon associated with such a one of first and second print heads 134, 144 would be deleted.When a light source such as a laser is used, the application means may comprise mirrors and prisms to access each of the two or more printing stations using a single laser.) Also, the importance of being able to print yellow, magenta and cyan using just one print head (and black using another) cannot be overstressed. For very precise registration, it must be recognized that two print heads that are ostensibly identical may in fact differ very slightly in dimensions, or be slightly non-parallel; two different sensors may differ slightly in sensitivity or response time when detecting the appearance of the clamp, so that error may result in defining the position of the first printable line, etc.Such sources of error have no effect, however, with regard to printing within a single ribbon/print head system, while on the other hand the availability of the second ribbon/print head system for printing black text avoids need to use the more expensive y, m, c, b ribbon and permits faster printing of text.

Figure 2 shows a structure similar to that of Fig.

1B except employing a platen in lieu of a drum. The distinction between a platen and drum essentially lies in the fact that the drum grasps and holds the substrate but the platen does not. Both the drum and platen work by frictional pressure to advance the ribbon while printing, but the platen lacks positive control of the substrate, e.g., during successive transfers of yellow, magenta and cyan images. Consequently, control of substrate movement may not be as precise with the platen as with the drum, but is adequate nevertheless for many printing purposes.

Indeed, such a procedure is quite adequate in the context of Fig. 2 in the case that the second ribbon/print head system is intended to provide an "inserted image for which precise registration relative to that of the first ribbon/print head system is not required.

Specifically, Fig. 2 shows a platen system 200 having a frame 201 to which is rotatably mounted a platen 202 by shaft 204. Platen system 200 includes a first ribbon 206 that may include on one side thereof, e.g., a repeating series of yellow, magenta and cyan color panels of heat sensitive ink or dye, each of such panels having a length nearly equal to that of the substrate to which an image is to be transferred. First ribbon 206 is unwound from a first supply roll 208 rotatably mounted on frame 201 by shaft 209, and after use 7s will be discussed below, first ribbon 206 is wound onto first takeup roll 210, also rotatably mounted on frame 201 by shaft 211.Both of first supply roll 208 and first takeup roll 210 are provided with reversible stepping motors (not shown) whereby either of rolls 208, 210 can be energized to rotate and draw first ribbon 206 from the other, and both of rolls 208, 210 are provided with slip clutches (also not shown) in the usual manner so that first ribbon 206 can be drawn from one to the other under tension.

The side of first ribbon 206 that bears the aforesaid panels in this case faces outwardly from first supply roll 208 and first takeup roll 210.

Platen system 200 further comprises a second ribbon 212, which may, e.g., be a multiprint black ink ribbon for printing on plain paper. Second ribbon 212 is unwound from a second supply roll 214 which is rotatably mounted on frame 201 by shaft 215, and after use second ribbon 212 is wound onto second takeup roll 216, also rotatably mounted on frame 201 by shaft 217. Second supply roll 210 and second takeup roll 212 are likewise provided with stepping motors and slip clutches (not shown), and similarly the side of second ribbon 208 that bears the panels faces outwardly from second supply roll 214 and second takeup roll 216.

For illustration, platen system 200 will now be further described in terms of a thermal printing process, although the specific method to be employed is not so limited and may include any of the options defined previously under the "Terminology" section above (i.e., using different technologies, different classes, groups or sets of panels, etc.). As also shown in Fig. 2, platen system 200 further comprises a first print head 218 and first ribbon guides 22u which serve to define the angle of contact between first ribbon 20G and platen 202. A sheet of substrate 224 is 'sandwiched' between first ribbon 206 and platen 202 to be printed upon in the usual method of thermal transfer. On the outward side of first print head 218 there is mounted to frame 201 a spring-loaded first driver motor 226 in the usual fashion so as to cause forward or backward motion of first print head 218 as desired.Platen system 200 further comprises a second print head 228 and second ribbon guides 230 which serve to define the angle of contact between second ribbon 212 and plated 202. Likewise, a springloaded second driver motor 232 is mounted to frame 201 outwardly from second print head 228 in the usual fashion so as to cause forward or backward motion of second print head 228 as desired for printing.

In light of the variety of panels available on both first and second ribbons 206, 212, and the need on occasion to traverse through one or the other of those ribbons in order to corne to a desired type of panel, it must be possible when so doing (i.e. when not printing) to draw both of tirst and second print heads 218, 228 back from the corresponding first and second ribbons 206, 212 so as (1) to avoid unnecessary wear on the respective print head; (2) to avoid advancing (or wearing upon) a sheet of substrate 224 disposed between one or the other ribbon and platen 202, and (3) to avoid wastage of ribbon, especially in a Winter that is not equipped to identify unused ribbon portions. To assist in controlling a sheet of substrate 224 during such process, platen system furtner comprises substrate guiae 234 ri:::edly attaches ro frame 201 to help guide the leading edge of substrate 224 rrom tne region or first print head 218 to that of second print head 22o, as well as pinch rollers 236 that are rotatably attached to frame 201 and aid in holding a sheet of substrate 224 against platen 202.

It should be noted that in Fig. 2, both of first and second print heads 218, 228 are disposed to conduct printing on substrate 224 simultaneously. That is, shortly after the encounter of substrate 224 with platen 202 by rotation of the latter in the direction of arrow 238, printing by first print head 218 and first ribbon 206 can commence.The timing by which such printing is initiated at the first printable line and subsequentiy continued os to each iine thereafter can be controlled as previously described, e.g. by a sensor inc s00!) tnat has detectec the leading edge of substrate 224 and Dy a pulse count generated by a shaft encoder (not shown) on the platen snaft in the manner of the previous embodiment of the invention (Fig. IA). Ane circumferential distance R along the print surface of the substrate between first print head 218 and second print head 228, and the nature of the desired second image, derines the number of encoder pulses at which printing should commence using second ribbon 212 and second print head 228. For accurate registration of successive images, it is also required, of coourse, that first and second print heads 218, 228 be aligned precisessly parallel. During all of such printing, it may be noted that (1) substrate 224 will be held against platen 202 by at least one of pinch rollers 236.

Although the structure of Fig. 2 appears similar to that of Fig. 2 of the '302 patent, that patent merely describes the use of two or more print heads and ribbons in a conventional thermal transfer process to transfer successive colors onto a substrate in forming a full color image. The present invention is thus distinguished in part by the fact that either or both of first and second ribbons 206, 228, and similarly first and second 'print heads' 218, 228, include any desired combinations of printing technologies, or of panel sets, groups, etc., including the use of precoat or overcoat, that are adapted therefor as previously noted. In particular, deposition of, e.g. precoat onto a substrate, can be carried out using a print head of lower (e.g. 150 Dip1) resolution than is used in full color image transfer, thereby saving expense both in the cost of the print head and in the amount of memory required to transmit print data for those fewer but larger dots. Moreover, the successive transfer of color images (e.g.

yellow, magenta and cyan) that is carried out by successive print heads in the indicated patent can instead be carried out by a single print head in the present invention, by reciprocating movement of platen 202 and an appropriate ribbon, hence the one or more additional print heads of the invention can be used for additional purposes as previously noted. During such reciprocal movement of platen 202, substrate 224 continues to be held by the particular pinch roller 236 that is located just in front of the ribbon 206 or 212 being used, so printing can take place very near to the leading edge of substrate 224, and secondly that holding action of pinch roller 236 allows such back and forth movement without introduction of unacceptable registration errors.

Similarly, to obtain accuracy of registration between successive images, the Moriguchi et al. '212 patent relies on a constant sped of movement of the belt which transports the substrate, whereas in the present invention the use of a shaft encoder defines such registration accuracy in terms of specific accurately measureable displacements of the substrate instead. Dependence upon a constant rate of substrate movement, in light of feedback errors known to occur with constant speed motors, may be acceptable in the case of printing with just one color, but becomes unacceptable when different colors are to be printed successively onto the same substrate, hence the method of positive substrate control using a rotary encoder as in the present invention becomes essential.

In addition, it is known to achieve a lesolutiols that is effectively twice that of the resolution of the print head itself by moving the substrate by one-half lines between successive printings of a dot rather than by the full lines that would be defined, e.g., by a 300 DPI print head--that is, by 1.67 mil rather than 3.33 mil. That process can also be carried out using the present invention since, in the embodiments of the invention that employ such an encoder, (1) the substrate is initially grasped by a clamp and remains so held during the multi-image printing process; and (2) there is defined a fixed displacement of each respective sensor from the corresponding print head so that th precise location on the substrate of the first printable line and each subsequent line or half-line is thus determinable.It will be noted below, however, that the present invention also, and uniquely, provides means for achieving such "double resolution" printing in the transverse as well as the longitudinal direction.

Fig. 3 shows a variation of the invention in which successive print heads are arranged in line. Specifically, print assembly 300 is mounted on frame 301 and includes as major components first print station 302, second print station 322 and substrate assembly 342. First print station 302 further comprises first supply roll 304, first ribbon 306, and first takeup roll 308, which are respectively disposed as, and operate in the manner of, the ribbon assemblies previously described and shown in Fig. 2. First print station 302 also includes first print head 310, first print head motor 312 (for moving first print head 310), first platen 314 and first sensor 316.Second print station 322 further comprises second supply roll 324, second ribbon 326, and second takeup roll 328, which are likewise disposed as, and operate in the manner of, the ribbon assemblies of Fig. 2, except in that second print station 322 is displaced from first print station 302 a distance R along a straight line (rather than about the circumference ot the circle defined by the substrate surface as in Eig. 2). second print station 322 also includes second print head 330, second print head motor 332 (ror moving second print head 330 forward and backward), second platen 334 and second sensor 336.

Substrate assembly 342 serves to conduct a sheet of substrate 344 in the direction of arrow 346 so as to accept the transfer of successive images from first and second print stations 302, 322. The substrate assembly 342 further comprises first and second belt wheels 348, 350 and spacer wheel 352, each of which is rotatably connected to frame 301 and around which is wrapped belt pair 354.Preferably, spacer sheel 352 is also slidably mounted to frame 301 (as within a slot and lock) so as to permit some movement thereof outwardly zdownwaraly in Fig. 3) from first and second belt wheels 348, 35u, and thus to establish a desirta degree of tension in De t pair 354. otorIencoder 356 is also at- tached to the shaft of second belt wheel 350 and serves (1) to drive second belt wheel 350 and hence belt pair 354 in the direction of arrow 346, and (2) to provide a record of tne position of clamp 358 that connects across belt pair 354.Clamp 358 serves to grasp the leading edge of a sheet o substrate 344 and convey the same through first and second print stations 302, 322 for printing thereon.

Sheets of substrate 344 are supplied to print assembly 300. In Fig.

3 herein, clamp 358 is shown in outline as clamp 358' in the lower right hand corner thereof in a position passing around first belt wheel 348, i.e.

in a position so as to initially grasp a sheet of substrate 344. Upon further activation of motor/encoder 356, substrate 344 willl be transported in the generally counter-clockwise direction indicated by arrow 346, 50 that clamp 358 cornes into position to be detected by first sensor 316.

Following that first detection of substrate 344, tne first printable line thereof is defined as previously described, and first print station 30, can commence a first printing operation kllch, if it is taken that first ribbon 306 has already been placed in a position such that a desired panel thereof is appropriately lined up therefor, consists of (1) energizing first print head motor 312 so as to move first print head 310 forward (downward in Fig. 3) into contact with first ribbon 306, and then (2) transmitting print data to first print head 310 in the desired image pattern.First takeup roll 308 is energized by a motor (not shown) so as to advance first ribbon 306 at the same rate at which belt pair 354 (as driven by motor/encoder 356) advances substrate 344, and first platen 314 can be allowed to rotate under some frictional resistance thereto in response to the movement of clamp 358 and substrate 344 so as to maintain a degree of tension within substrate 344. After some movement (i.e., approximately the distance R) of substrate 344 as just described, clamp 358 will come into a position to be detected by second sensor 336, and printing at second print station 322 can commence in the same manner as was just described with reference to first print station 302.

As in the previous embodiment of Fig. 2, printing can occur simultaneously in first and second print stations 302, 322 (or, e.g., in a third print station as well for separate printing of yellow, magenta and cyan), and for additional printing, substrate 344 can be transported entirely around the path of belt pair 354 so as to be sensed again by first sensor 316, and further printing can then be carried out as previously described. (Continued counterclockwise movement of substrate 344 is preferred to reverse movement thereof in order to maintain the preestablished degree of tension in substrate 344.Also, although printing by two or more print heads at once is possible, for the highest registration accuracy, and to avoid inordinate stretching of substrate 344 when the print head pressure over platens 314, 334, etc. is high, it is preferable to print with just one print head at a time.) The following description outlines an additional capability of the invention wherein advantage is taken of the indicated control of the substrate. Specifically, Fig. 4 shows a device that permits placement of an image from a print head that is of a shorter length than the width of the image-receiving substrate at a desired lateral or transverse position on that substrate. Image positioner 400 as mounted on printer frame 401 is shown in both a top plan (4A) and a cross-sectional (4B) view taken through the line 4B - 4Bt of Fig. 4A.Image positioner 400 includes a carriage frame 402 that is fixedly mounted to printer frame 401 by means of first and second frame members 404a, 404b, which are in turn interconnected by cross members 406a, 406b. Carriage 408, which principally comprises two parallel plane members 409a, 409b and first and second struts 410a, 410b is slidably mounted to cross members 406a, 406b and provides the desired positioning action. As can be seen in Fig. 4A, carriage 408 is positioned to lie " above" a sheet of substrate 411.

Carriage 408 further comprises supply shaft 412 disposed transversely between members 409 a, 409b and onto which supply roll 414 is rotatably mounted, takeup shaft 416 which ; likewise disposed transversely between members 409a, 409b and onto which takeup roll 418 is rotatably mounted, and ribbon 420 which is disposed between supply roll 414 and takeup roll 418 in the usual fashion.

Also mounted on carriage 498 is a print head a22 which faces ribbon 420 in t usual manner and is controlled in terms of motion towards and away from ribbon 420 by spring-loaded motor 424 that is mounted to third strut 425 that extends between members 409a, 409b. A platen 426 or the like (which is "behind" substrate 411 and thus not seen in Fig. 4A) is rotatably mounted to frame 401 by shaft 428 and faces towards substrate 411 so that ribbon 420 can be pressed against substrate 411 by print head 422 in the usual manner.

Positioning of the assembly that includes supply roll 414, takeup roll 418, ribbon 420 and print head 422, and which thus defines the transverse or lateral location on substrate 411 at which print head 422 will act to transfer an image, is controlled by a belt 430 that extends from a first side of carriage 408 at connection point A on member 409a; thence to first pulley 432 which is attached to first frame member 404a; thence across carriage 405 to reversible pulleyfmotor 434 which is attached to second frame member 404b; and thence to a second side of carriage 408 at connection point B on member 409b.By activation of reversible pulley/motor 434, it is clear that the lateral or transverse (horizontal in Fig. 4A) position of carriage 408 can be adjusted relative to the underlying position of substrate 411, and hence that the position on substrate 411 at which an image will be transferred by print head 422 can be adjusted as desired. This mechanism thus has an advantage over that which employed spacers for such lateral adjustment purposes as described in Appl. Ser. No. 08/047,144 filed Apr. 12, 1993, in that the positioning of carriage 408 is incrementally adjustable, and further that such positioning can be carried out by electronic control (e.g., as by a rheostat) without requiring manual entry into the printer.

A similar mechanism for such lateral positioning of a carriage which bears the printing system is shown in Fig. 5. Specifically, image positioner 500 as mounted on printer frame 501 is shown in both a top plan (5A) and a cross-sectional (5B) view taken through the line 5B - 5B' of Fig. 5A. Image positioner 500 includes a carriage frame 502 that is fixedly mounted to printer frame 501 by means of firs and second frame members SO4a, 504b, which are in turn interconnected by cross member 506 which is fixedly mounted therebetween, and by threaded bolt 507 which is rotatably mounted therebetween.Carriage 508, which principally comprises two parallel plane members 509a, 509b and first and second struts 510a, 510b is slidably mounted to cross member 506 and screwably mounted to threaded bolt 507 and provides the desired positioning action. As can be seen in Fig. 5A, carriage 508 is positioned to lie "above" a sheet of substrate 511.

Carriage 508 further comprises supply shaft 512 disposed transversely between members 509a, 509b and onto which supply roll 514 l rotatably mounted, takeup shaft 516 which is likewise disposed transversely between members 509a, 509b and onto which takeup roll 518 is rotatably mounted, and ribbon 520 which is disposed between lpply roll 514 and takeup roll 518 in the usual fashion.

Also mounted on carriage Sog is a print head 522 which faces ribbon 520 in the usual manner and is controlled in terms of motion towards and away from ribbon 520 by a spring-loaded motor 524 that is mounted to third strut 525 that extends between members 509a, 509b. A platen 526 or the like (which is "behind" substrate 511 and thus not seen in Fig. 5A) is rotatably mounted to frame 501 by shaft 528 and faces towards substrate 511 so that ribbon 520 is pressed against substrate 511 by print head 522 as usual.

Positioning of the assembly that includes supply roll 51t, takeup roll 518, ribbon 520 and print head 522, and which thus defines the transverse or lateral location on substrate 511 at which print head 522 will act to transfer an image, is controlled by rotation of threaded bolt 507, which as indicated passes through a like set of threads within carriage 508 and is rotatably connected at respective ends thereof to first and second frame members 504a, 504b. As one means of rotating threaded bolt 507, Fig. 5A shows an extension shaft 530 which extends outardly from first frame member 504a and onto the end of which is located knob 532 which can be manually turned so as to turn threaded bolt 507. Of course, rotation or turning of threaded bolt 507 can optionally b controlled by a motor (not shown) as in the embodiment of Fig. 4.

In either of the embodiments of Figs. 4, 5 it becomes possible in this aspect of the invention not only to print different images using different print heads on a single sheet of substrate, but if either of the structures of Figs. 4, 5 is taken to replace one or more of the print heads of, e.g., Fig. 3, any of such images can be placed at any desired lateral location across the width of the substrate. By controlling the timing by which print data are sent to the print head, a desired placement along the length of the substrate is also achieved in the usual manner.Indeed, by repeated use of one or the other of the structures of Figs 4, 5 in conjunction with reciprocating movement of the substrate beneath either of those structures in the usual fashion, an image can be created that encompasses the full size of that substrate even though the print head extends only part of the way thereacross. Thus, for economic reasons, a print head that is of a smaller length (e.g., 4 inches) can be employed to produce a full 8-inch image, or for greater printing capability a larger substrate (e.g., 18 inches in width) and similarly larger substrate-handling capabilities (i.e., substrate trays, guides and the like) can be used with an 8-inch print head to print a 16-inch or even larger image.

An example of such a process is shown in Fig. 6, which includes a sheet of substrate 600 and successive first, second, third and fourth print regions 602, 604, 606 and 608. In an initial printing, substrate 600 is grasped at the leading edge A thereof at a time that, for example, carriage 408 of Fig. 4 is disposed at the far right side of carriage frame 402. Transport of substrate 600 upwardly in Fig. 6, or of substrate 411 downwardly in Fig. 4, will then, along with an appropriate transmission of print data, result in an image transfer in first print region 602. First and second print regions 502, 604 may be distinguished as indicated for the reason, e.g., that each of them correspond approximately to the size of a single panel on a ribbon.In any case, continued transport of substrate 600 (or 411) as indicated and corresponding transmission of additional print data will then cause the transfer of an image into second print region 604. Carriage 408 (or carriage 508 in Fig. 5) is then moved to the far left side by pulley/motor 434 in Fig. 4 (or by turning threaded bolt 507 in Fig. 5), and print data for the transfer of an image in third print region 606 is transmitted, and similarly as to additional data in fourth print region 608. Accurate longitudinal placement of the substrate (e.g., by detection of clamp 358 as previously described) is of course required.

It should be noted that just as previous embodiments of the invention have employed a shaft encoder to record and control the longitudinal movement of a sheet of substrate, so can either of the apparatus of Figs. 4, 5 be equipped with a shaft encoder (not shown) that will record and control the lateral or transverse movement of one or the other of carriages 408, 508, and hence of the lateral or transverse disposition of print heads 422, 522.Such transverse disposition, just as the longitudinal disposition, can be controlled to "half-line" (or "half-dot separation") scale, i.e., to within 1.67 mil, hence the resolution of the resulting image--and indeed the "matching" of images along the line of abutment B B' as between the images of first and third print regions 602, 606, or of second and fourth print regions 604, 608--can again be controlled more finely than is the resolution of print head 422 or 522. Within each of first, . . . , fourth print regions 602, . .. , 608, or any other arbitrarily selected print region, (1) a first printing is carried out at a 300 (transverse) X 600 (lon- gitudinal) DPI resolutionn employing 1.67 mil "half-line longitudinal steps; (2) one or the other of carriages 408, 508 (as is used in the particular embodiment of the invention) is moved transversely by 1.67 mil; and (3) a second printing at that same 300 X 600 DPI resolution is then conducted in which the dots produced are placed in between the dots transferred in the first printing so as to yield ''half-dotll transverse resolution as well.

The dot size is changed similarly, by employing an appropriately programmed print controller to alter the time or modulation of each heating pulse for a thermal transfer print head, and similarly for other type print heads. A first set of alternating dots derived from alternating print data (using all of the elements of the print head) is printed as required by the image data along one line, carriage 408 or 508 is moved transversely by 1.67 mil as just stated, and then the intervening set of dots is printed from the intervening print dc l as the image may require. That process is then repeated for subsequent longitudinal lines (or half-lines) as controlled by longitudinal substrate movement.Such higher re solution printing, which is particularly useful in, e.g., printing transparencies that are to be projected to a much larger scale visual image, can if desired be a special purpose option that is selectable through the print controller, and involves both (1) programming of the carriage and substrate movement as indicated and (2) separation of the entirety of the image data into those two interleaved sets of data as described. Of course, with the apparatus described one may similarly program the carriage and substrate movements so as to interleave three or more sets of print data.

Returning to a more general theme, the ability provided by the invention to select a direct energy process, or one or more out of two or more ribbons (as in Figs. 1 - 3) for use simultaneously or separately presents advantages in conducting general printing operations. The different choices available lie as well in the types of ribbons that can be installed. Some possible choices are shown in Table I:

Embo- Ribbon Description diment # 1 Repeating series of y, m, c thermal transfer panels, each of which is ii inches long.

Black Black thermal transfer ribbon.

Use: printing up to 8.5x11 inch black or color print; use one or more panels of the set of y, m, c panels for highlight printing on black image printed by the ribbon.

Advantages: Low cost 8.5 x 11 inch black image and color image printing capability without changing ribbons.

Disadvantages: For printing small format color images, the portion of the large ribbon panel is wasted (smaller format ribbon could have adequately done the print job in such imaging requirements). For printing small format color print, need to have means to use the unused ribbon portions.

2 #I Same as fit 1 except each color panels are 44 inches long with sequence numbers on each portion of panels or other means to use unused portion of panels.

#2 Black thermal transfer.

Advantages: Low cost 8.5 x 11 inch black image and flill color and highlight printing capability as in #1; unused portion of panels are likely to be longer in this embodiment and therefore may be used for the next full color or highlight color image.

Disadvantages: Tooling cost for longer panel is more expensive for 44 inch panels as compared to 11 inch panels; longer panels incorporated more complex ribbon marking and sensing; takes longer time to wind 44 inch Embo Ribbon Description diment panels when 11 inch color image is printed as compared to with 11 inch panels (33 inch long panels can be used instead of 44 inch panels to reduce tooling cost).

3 #1 Black thermal transfer.

(yellow thermal transfer 1000 inch +blue thermal transfer 1000 inch) x 3 times, means to use unused portions of panels.

Advantages: black and black plus one of two or both highlight colors can be printed; two color image by printing with second ribbon in two passes Disadvantages: full color capability is not available.

4 vI Black thermal transfer err"2 Repeating series ofy, m, c panels each ii inches long 100 times + 1000 inches long yellow thermal transfer or red thermal transfer highlight color with means to use unused portions of ribbons.

Advantage: The second ribbon can image one color highlight printing on a printed document printed by first ribbon or on blank paper; low cost black imaging and color imaging capability; black and full color imaging inserted in black document capability.

Disadvantage: Yellow or y, m, c set of panels may remain unused and wasted when the other panel is used up and therefore the ribbon is replaced.

5 ffl Repeating series of y, m, c thermal transfer ribbon each panel is Ii inch long.

2 Repeating series of y, m, c Dye Diffusion Thermal Transfer type ribbon each panel is 11 inches long.

Embo Ribbon Description diment Advantage: Two types of ribbon are available to print at any time to give flexibility of printing without having to manually change the ribbons for thermal transfer printing or Dye Diffusion gray scale high quality printing.

Disadvantage: Black ribbon is not installed and therefore black printing by the y, m, c panels is more expensive and takes more print time.

6 = 1 Repeating series of precoat, black thermal transfer panels each 200 inches long with means to use unused portions of panels Repeating series of y, m, c thermal transfer panels each 11 inches long.

Advantage: precoat and/or black can be printed by first ribbon before the paper comes in front of second ribbon for color or highlight printing; precoat and black panels are not automatically wasted when y, m, c ribbon is used up.

Disadvantage: Precoat or black panels may remain unused and wasted when the other panel of the same ribbon is used up and therefore the ribbon is replaced.

7 #1 Repeating series of precoat, y, m, c thermal transfer ribbon each panel is 11 inches long.

#2 Repeating series of y, m, c thermal transfer ribbon.

Advantage: either printing on smooth paper without precoat or on rough surface with precoat can be printed; ribbon with precoat panel is used only when printing on rough surfaces.

Disadvantage: Black image printing requires printing with all y, m, c panels Embo Ribbon Description diment and therefore is costly, highlight printing is expensive.

8 I Precoatribbon.

(Repeating series of y, m, c thermal transfer series 30 panels+1000 inch black thermal transfer) x 3 times with means to use unused portion of ribbon.

Advantage: The paper can be printed with a precoat layer by 1 sot ribbon and then the second ribbon can print the colors and/or black image over precoat layer, inexpensive precoat roll of ribbon; precoat layer is used only when required.

Disadvantages: Printing of color after black or vice versa image document requires winding the ribbon until the required other panels are brought in front of the print head ready for printing and this takes longer time for printing thus this embodiment is more effective when there is a batch of print jobs which are all black or ftill color.

9 #1 1 Black thermal transfer.

#2 Multi-print type 200 inch long panel of a highlight color such as yellow and set of 100 11" long y, m, c panels. with means to use the unused portions of panels.

Advantages: Low -rst black, full color capability, low cost highlight printing, low cost color highlight alphanumeric printing.

Disadvantage: Multi print ribbon may not print consistent high quality printing.

10 ffl Repeating series of y, m, c thermal transfer ribbon for dot modulation.

Embo Ribbon Description diment Repeating series of y, m, c thermal transfer ribbon for 1 fixed size dot printing.

Advantage: Higher quality color printing with many gray levels is possible as well as fixed size dot printing for less data.

Disadvantage: Black printing is expensive.

ii #1 No ribbon on one side so that special coated paper can be printed with direct thermal printing.

Repeating series of Ii long y, m, c thermal transfer panels.

Advantages: Direct printing is possible for special coated paper.

Disadvantage: Direct coating does not print on plain paper.

12 =1 8.5 inch wide thermal transfer ribbon which comprises 0.5 inch wide thermal transfer magnetic ink for character recognition and rest of the panel with black color.

#2 8.0 inch wide conventional ribbon y, In, c thermal transfer (repeating 11 inch panels).

Advantages: Documents like checks can be printed in one pass both magnetic as well as black printing in the selected area.

Disadvantages: Magnetic ink coating is wasted when image does not require magnetic coating.

13 X1 Black Thermal Transfer ribbon.

Blue Blue Thermal Transfer Advantages: Black or Blue image as well as Black and Blue image can be Embo Ribbon Description diment printed.

Disadvantage: Full color printing is not possible.

14 #I Replenishing type black thermal transfer ribbon.

Repeating series of y, m, c thermal transfer panels of Ii inches long.

Advantages: Low cost black printing because the thermal transfer layer can be replenished.

Disadvantages: Printer is more costly due to the cost for replenishing ink sub-system.

15 trl Black thermal transfer ribbon.

Repeating series ofy, m, c thermal transfer panels of 11 inches long with means to use the unused portions of panels.

Advantages: Black, full color letter size and small format color image can be printed economically.

Disadvantages: Need Read Head to read sequence numbers.

16 f I Repeating series of y, m, c thermal transfer repeating all panels, each 4 inch wide panel is 5 inches long.

M2 8.5 inch wide thermal transfer ribbon.

Use: printing up to 8.5 x 11 inch black or small format up to 5 x 4 inch color print or 8.5 x 11 inch black plus small format color inserted in black document.

Embo- Ribbon Description diment Advantages: 4 inch print head is fixed in location, therefore hardware is less expensive than X17,small format color imaging capability, lower cost than 8.5 x 11 inch color print, since the print head is only 4 inches wide, hardware cost is lower than that for 8.5 inch wide print head Disadvantages: Large size 8.5 x 11 inch color image may have registration errors due alignment between two images is more difficult Note:Longer image can be printed by printing 4 x S inch image first from top edge of the image and then another up to 4 x 5 image adjoining the first image's bottom edge by another set of y,m,c color panels 17 I Repeating series of y, m, c thermal transfer panels, each 4 inch wide and 5 inches long; the 4 inch wide print head/ribbon assembly is mounted on carriage and can be axially moved by belt or screw 8.5 inch wide thermal transfer ribbon Use: printing up to 8.5 x 11 inch black or small format up to 5 x 4 inch color print or 8.5 x 11 inch black plus small format color inserted in black document Advantages:Color 5 x 4 image can be printed anywhere in the black document; since each color panel is only 5 inches long, it is simpler to sense; since the print head is only 4 inches wide hardware cost is lower than that for 8.5 inch wide print heads Embo Ribbon Description diment Disadvantages: Large size 8.5 x 11 inch color image may have registration errors due alignment between two images is more difficult; hardware is more expensive than X16 because means to move the print head axially is incorporated.

Note: Longer image can be printed by printing 4 x 5 inch image first from top edge of the image and then another up to 4 x 5 image adjoining the first image's bottom edge by another set of y,m,c color panels 18 X1 Repeating series of y, m, c thermal transfer repeating all panels, each 4 inch wide panel is 11 inch long; print head/ribbon assembly is mounted on carriage and can be axially moved by belt or screw.

rr2 8.5 inch wide thermal transfer ribbon.

Use printing up to 4 x 11 inch image anywhere on the paper and on black image printed by another print head. Low cost blck fill page image, Advantages: Up to 11 inch long color images can be printed; since the print head is only 4 inches wide hardware cost is lower than that for 8.5 inch wide print head Disadvantages: Large size 8.5 x 11 inch color image can not be printed without stepping of carriage.

Note: Wider image can be printed by processing the image and printing the second image after moving the paper back to the original position alter printing the first image.

19 same as #17 except 4 inch wide ribbon panels are ii inches long Advantages: Up to 11 inch long color images can be printed anywhere on the 8.5 x 11 document; since the print head is only 4 inch wide hardware cost is lower than that for 8.5 inch wide print head Disadvantages: Large size 8.5 x 11 inch color image may have registration errors due alignment between two images is more difficult; hardware is more expensive than #16 because of means to move the 5 inch print head axially is incorporated Note:Wider image also can be printed by printing first 4 inch wide image from the edge of image and then printing upto another 4 inch wide image starting from the other edge 20 WI Precoatribbon #2 Yellow ribbon #3 Magenta ribbon Cyan Cyan ribbon Advantage: Printing any color or full color on special as well as plain paper at low cost.

Disadvantage: Need four print heads and therefore equipment is expensive 21 #1 Yellow ribbon #2 Magenta ribbon #3 Cyan ribbon #4 Black ribbon Advantage: Low cost printing any color, full color and black Disadvantage: Four head is expensive NOTES:The above ribbon embodiments can be changed to optimize print job and some of the example to change are as follows: Note Embodiment #1 to Xc5,9,2 0, 11, 12, 13, 14, 16, 17, 18, and 19 can incorporate precoat panels in addition to y, m, c and/or black to enable printing on wider variety of plain paper.

Note #2: In embodiments 1,2,3,4,ó,7,8,9,10,11,16,17,18, and 19 #2 ribbon of 12,13,14 and 15 Dye Diffusion Thermal Transfer or any other technology for the ribbon can be used instead of one or both ribbons of thermal transfer shown in the table.

Note =3: Panel number and portion of panels can be marked or means is provided so that unused portion of panels can be used.

Note i4: Some of the panels can incorporate magnetic ink for character recognition.

Note =5: Some ofthe panels can have multiprint capability to enable printing more than one print by the ribbon.

Note > 6: Ribbon can be replenishing type so that a replenishing subsystem can replenish one or more ribbons.

Note 7: Marks can be on the printing area of the ribbon.

The foregoing example should be considered to be representative only and not exhaustivee since a person or ordinary sKili in the art can easily conceive of other examples that may differ from those indicated in some detail. Thus, the ribbons in any of embodiments 1 to 5 or 9 to 15 may also incorporate additional precoat panels to permit printing on a wider variety of plain paper; and in any of embodiments 1 to 4 and 6 to 11, as also in the second ribbon of embodiments 12 and 13 through 15, the ribbon can be of dye diffusion or other technology instead of thermal transfer. Also any other example may, like example 5, include both thermal transfer and dye diffusion technologies. Such ribbons may also incorporate the panel marking and usage procedures previously described.

Regarding the printer structure, departures may be made from the precise structure shown in the figures, e. g. such that the printing assemblies are oriented at different angies. Similarly, one may use the known procedure in which an image is first transferred to a drum and is then copied onto paper (which would use one or the other paper transfer process).

Claims (58)

1. A printer comprising: substrate handling means; two or more elongate ribbons each bearing on a surface thereof one or more panels of transfer mate rial adapted to transfer an image onto a substrate; and two or more energy sources each disposed in co operation with one of said two or more elongate rib bons, and capable of bringing about a transfer of an image from said one or more panels of transfer mate rial onto a substrate; wherein at least one of said two or more elongate ribbons comprises a repeating series of color panels.

2. The printer of claim 1 wherein a transfer material of at least one of said two or more elongate ribbons comprises a precoat material.

3. The printer of claim 1 wherein a transfer material of at least one of said two or more elongate ribbons comprises one or more black panels.

4. The printer of claim 1 further comprising means for separating composite electronic print data into at least two subsets thereof and directing each of said subsets to separate ones of said two or more energy sources.

5. The printer of claim 1 further comprising search means for identifying unused portions of said one or more panels of transfer material on at least one of said two or more elongate ribbons.

6. The printer of claim 5 wherein said search means are adapted for application to separate ones of said repeating series of color panels.

7. The printer of claim 1 further comprising a printer controller at least adapted to activate just one of said two or more energy sources at a time.

8. The printer of claim 1 wherein said substrate handling means comprises means for grasping and holding a sheet of said substrate during the course of repeated image transfers thereon.

9. The printer of claim 8 wherein at least one of said two or more elongate ribbons comprises a precoat material.

10. The printer of claim 8 wherein at least one of said two or more elongate ribbons employs a technology different from the technology employed by at least one other of said two or more elongate ribbons.

11. The printer of claim 8 wherein said elongate ribbon that comprises a repeating series of color panels employs a different technology from that employed by at least one other of said two or more elongate ribbons.

12. The printer of claim 10 wherein said substrate handling means comprises a belt and clamp mechanism.

13. The printer of claim 8 wherein each of said two or more elongate ribbons employs the same technology.

14. The printer of claim 8 further comprising a printer controller at least adapted to activate just one of said two or more energy sources at a time.

15. The printer of claim 8 wherein at least one of said two or more elongate ribbons comprises one or more black panels.

16. The printer of claim 15 wherein said substrate handling means comprises a drum and clamp mechanism.

17. The printer of claim 15 further comprising search means for identifying unused portions of said one or more panels of transfer material on at least one of said two or more elongate ribbons.

18. The printer of claim 15 wherein said substrate handling means comprises a belt and clamp mechanism.

19. A printer comprising: two or more elongate ribbons each bearing on a surface thereof one or more panels of transfer mate rial adapted to transfer an image onto a substrate; two or more energy sources each disposed in co operation with one of said two or more elongate rib bons, and capable of bringing about a transfer of an image from said one or more panels of transfer mate rial onto a substrate; and a belt and clamp mechanism for handling sheets of said substrate.

20. The printer of claim 19 wherein at least one of said two or more elongate ribbons comprises one or more panels of precoat material.

21. The printer of claim 19 wherein at least one of said two or more elongate ribbons comprises one or more black panels.

22. The printer of claim 19 further comprising means for separating composite electronic print data into at least two subsets thereof and directing each of said subsets to separate ones of said two or more energy sources.

23. The printer of claim 19 further comprising search means for identifying unused portions of said one or more panels of transfer material on at least one of said two or more elongate ribbons.

24. The printer of claim 23 wherein said search means are adapted for application to separate ones of said repeating series of color panels.

25. The printer of claim 19 further comprising a printer controller at least adapted to activate just one of said two or more energy sources at a time.

26. The printer of claim 19 wherein at least one of said two or more elongate ribbons comprises a repeating series of color panels.

27. The printer of claim 26 wherein at least one other of said two or more elongate ribbons comprises one or more panels of precoat material.

28. The printer of claim 26 wherein at least one other of said two or more elongate ribbons comprises one or more panels of material adapted to serve as both a precoat and an overcoat material.

29. The printer of claim 26 wherein at least one other of said two or more elongate ribbons comprises one or more panels of overcoat material.

30. A printer comprising: substrate handling means; two or more elongate ribbons each bearing on a surface thereof one or more panels of transfer mate rial adapted to transfer an image onto a substrate; and two or more energy sources each disposed in co operation with one of said two or more elongate rib bons, and capable of bringing about a transfer of an image from said one or more panels of transfer mate rial onto a substrate; wherein at least one of said two or more elongate ribbons employs a technology different from the technology employed by at least one other of said two or more elongate ribbons.

31. The printer of claim 30 wherein at least one of said two or more elongate ribbons employs a thermal transfer process and comprises a repeating series of color panels.

32. The printer of claim 30 wherein at least one of said two or more elongate ribbons employs a dye diffusion process and comprises a repeating series of color panels.

33. A printer comprising: substrate handling means; and two or more energy sources, wherein at least one of said energy sources is adapted to form an image on a substrate by direct energy trans fer.

34. The printer of claim 33 further comprising: at least one elongate ribbon bearing on a surface thereof one or more panels of transfer material ad apted to transfer an image onto a substrate; wherein at least one of said energy sources is disposed in cooperation with said at least one elongate rib bon and capable of bringing about a transfer of an image from said one or more panels of transfer mate rial onto a substrate.

35. A printer comprising: two or more energy sources adapted to form an im age on a substrate; and sheets of substrate adapted to receive an image; wherein: said sheets of substrate are mounted onto a drum during the course of said formation of an image on said substrate by both of said two or more energy sources.

36. The printer of claim 35 wherein said two or more energy sources form said images using the same technology.

37. The printer of claim 35 wherein said two or more energy sources form said images using respectively different technologies.

38. The printer of claim 35 further comprising: at least one elongate ribbon bearing on a surface thereof one or more panels of transfer material adapted, in cooperation with at least one of said two or more energy sources, to transfer an image onto a substrate; and search means for identifying unused portions of said one or more panels of transfer material on at least one of said two or more elongate ribbons.

39. The printer of claim 38 wherein: said one or more panels of transfer material com prise repeating series of color panels; and said search means are adapted for application to separate ones of said repeating series of color panels.

40. The printer of claim 35 further comprising a printer controller at least adapted to activate just one of said two or more energy sources at a time.

41. The printer of claim 40 further comprising at least one elongate ribbon bearing on a surface thereof one or more panels of black transfer material adapted to transfer an image onto a substrate.

42. The printer of claim 40 further comprising at least one elongate ribbon bearing on a surface thereof a repeating series .of color panels of transfer materials adapted to transfer an image onto a substrate.

43. The printer of claim 42 further comprising at least a second elongate ribbon bearing on a surface thereof a precoat material.

44. The printer of claim 42 further comprising at least a second elongate ribbon bearing on a surface thereof a material adapted to form both a precoat and an overcoat on a substrate.

45. The printer of claim 42 further comprising at least a second elongate ribbon bearing on a surface thereof one or more black panels.

46. The printer of claim 42 further comprising means for separating composite electronic print data into at least two subsets thereof and directing each of said subsets to separate ones of said two or more energy sources.

47. The printer of claim 42 further comprising search means for identifying unused portions of said one or more panels of transfer material on at least one of said two or more elongate ribbons.

48. The printer of claim 42 wherein said search means are adapted for application to separate ones of said repeating series of color panels.

49. A printer comprising: substrate handling means; two or more elongate ribbons each bearing on a surface thereof one or more panels of transfer mate rial adapted to transfer an image onto a substrate; and two or more energy sources each disposed in co operation with one of said two or more elongate rib bons, and capable of bringing about a transfer of an image from said one or more panels of transfer mate rial onto a substrate; wherein at least one of said two or more elongate ribbons comprises a precoat material.

50. The printer of claim 49 wherein one of said two or more energy sources is adapted to transfer said precoat material in dimensions that are larger than the image transferred by at least one other of said two or more energy sources.

51. The printer of claim 49 wherein said precoat material is further adapted to serve as an overcoat material.

52. A printer comprising: substrate handling means; two or more elongate ribbons each bearing on a surface thereof one or more panels of transfer mate rial adapted to transfer an image onto a substrate; two or more energy sources each disposed in Co- operation with one of said two or more elongate rib bons, and capable of bringing about a transfer of an image from said one or more panels of transfer mat- rial onto a substrate; and means for providing transverse movement to at least one of said two or more elongate ribbons to gether with a corresponding one of said two or more energy sources that is disposed in cooperation with said at 1eR5t one of said two or mor. e1onre ribbons.

53. The printer of claim 52 wherein at least one of said two or more elongate ribbons comprises repeating series of color panels.

54. The printer of claim 52 further comprising means for applying said transverse movement in cooperation with said substrate handling means and with means for segmenting print data into portions by interleaving and separately transmitting said interleaved portions to an energy source, whereby said energy source and said ribbon are made to form an image of increased resolution in the transverse dimension.

55. The printer of claim 52 wherein: at least one of said two or more elongate ribbons is of a smaller transverse dimension than at least one other of aid two or more elongate ribbons; and one of said two or more energy sources is of a shorter length than at least one other of said two or more energy sources and is disposed in coopera tion with said at least one elongate ribbon having said smaller transverse dimension.

56. The printer of claim 55 wherein said energy source having said shorter length and said ribbon hav 'ng said shorter transverse dimension are cooperatively transversely movable.

57. The printer of claim 56 further comprising means for applying said transverse movement in cooperation with said substrate handling means and with the transmission of regionally segmented print data where by said energy source having said shorter length and said ribbon having said shorter transverse dimension are made to form an image of larger dimension than either of said shorter length or said shorter transverse dimension.

58. The printer of claim 1 wherein said substrate handling means further comprises means for automatic selection of substrate from at least two separate substrate trays.