This application relates to commonly assigned, copending U.S. application Ser. No. 13/334,574, filed Dec. 22, 2011, entitled: “INKJET PRINTING METHOD WITH ENHANCED DEINKABILITY”; U.S. application Ser. No. 13/334,661, filed Dec. 22, 2011, entitled: “INKJET PRINTER WITH ENHANCED DEINKABILITY”; U.S. application Ser. No. 13/334,683, filed Dec. 22, 2011, entitled: “LIQUID ENHANCED FIXING METHOD”; U.S. application Ser. No. 13/334,453, filed Dec. 22, 2011, entitled: “INKJET PRINTING ON SEMI-POROUS OR NON-ABSORBENT SURFACES”; U.S. application Ser. No. 13/334,473, filed Dec. 22, 2011, entitled: “INKJET PRINTER FOR SEMI-POROUS OR NON-ABSORBENT SURFACES”; U.S. application Ser. No. 13/334,487, filed Dec. 22, 2011, entitled: “METHOD FOR PRINTING ON LOCALLY DISTORTABLE MEDIUMS”; U.S. application Ser. No. 13/334,495, filed Dec. 22, 2011, entitled: “PRINTER FOR USE WITH LOCALLY DISTORTABLE MEDIUMS”; U.S. application Ser. No. 13/334,509, filed Dec. 22, 2011, entitled: “METHOD FOR PRINTING WITH ADAPTIVE DISTORTION CONTROL”, and U.S. application Ser. No. 13,334,524, filed Dec. 22, 2011, entitled: “PRINTER WITH ADAPTIVE DISOTRTION CONTROL”, each of which is hereby incorporated by reference.
This invention pertains to the field of printing.
Electrostatic and electrophotographic printing involves developing a latent electrostatic image with charged toner particles loaded onto an imaging drum and transferring them onto a substrate or a print substrate, particularly in the form of sheets or in the form of a continuous conveyor belt. As an example, in four-color printing, four latent images in the four-color separations (cyan, magenta, yellow, and black) are transferred to the substrate successively and in register on top of one other. In particular, the finished single color or multicolored latent image is then fused onto the substrate by a fusing device. This customarily takes place by a heatable fusing roller, which is rolled onto the toner image. The toner is heated up above its glass transition temperature, and thus melted, and simultaneously incorporated under pressurization into the substrate to which it is fused after it has been cooled. Adjacent toner particles are thereby combined, which finally form a polymer layer on the substrate.
Alternatively, fixing can be performed in other ways, for example, by exposing the toner and the substrate to which the toner is to be fused to microwaves. Such microwaves heat water in the printing substrate to which the toner is to fuse. This water heats the substrate. The substrate then transfers heat into the toner to cause the toner to reach the glass transition temperature. However, it has been difficult in the past for such microwave fusing systems to operate in the optimal fusing area (fusing window) between a fusing extent that provides an inconsistent gloss and blister formation of the toner on the substrate. This window is very narrow, in particular with the use of glossy-coated paper as the substrate.
To address such problems, U.S. Pat. No. 6,909,871 entitled Method and Device for Fusing Toner Onto a Substrate, filed by Behnke et al. on Apr. 14, 2003, proposes combining these methods and describes a fusing method wherein a heated fusing roller is used to heat the toner, under pressure, to a temperature that is greater or equal to a glass transition temperature, and additionally applying microwaves heat the toner on a substrate. In order to achieve a better energy input, Behnke et al. proposes that the substrate can be moistened before microwaves are applied to the substrate and suggests applying 100 degree C. hot steam to the substrate. Behnke et al. also suggests that the substrate could preferably be moistened on both sides, in order to avoid stressing and bending of the substrate and notes that one advantage of this technique is that the substrate carrying the toner can be warmed by the heat from the steam.
However, while the system that is described in Behnke et al. is useful for many purposes, there are many complications associated with the use of contact fusing such as is done with heated rollers or belts and in many applications fusing without using a contact surface such as a roller or belt is preferred.
Thus, what is still needed in the art are methods and printers that enable effective non-contact fixing of toner.
Printers are provided. One printer has an ink jet printer with an inkjet printhead to print an inkjet image on a receiver using an inkjet ink having a liquid with a boiling point a toner print engine to generate a toner image conforming to the ink jet image using toner particles with a glass transition temperature that is below the boiling point and to transfer the toner image into an unabsorbed volume of liquid ink of the inkjet image on the receiver and a fixing system having a first energy source to apply a first energy to the toner and the liquid sufficient to bring the liquid to the boiling point without bringing a heated surface into contact therewith. The toner particles are heated above the glass transition temperature by the combination of heat from the liquid and heating of the toner particles by the first energy so the toner particles are heated above the glass transition temperature without requiring heating of the receiver to the glass transition temperature of the toner.
The above and other objects, features, and advantages of the present invention will become more apparent when taken in conjunction with the following description and drawings wherein identical reference numerals have been used, where possible, to designate identical features that are common to the figures, and wherein:
The attached drawings are for purposes of illustration and are not necessarily to scale.
In operation, control system 20 causes an actuator 28 such as a motor (not shown) in transport system 24 to move endless transport belt 26 so as to advance a surface shown here as a receiver 42 in a printing direction 14 past ink jet printer 12 and toner printer 16. Receiver 42 can be any type of surface on which an inkjet ink and toner image can be processed using the methods that are described herein, and can comprise, without limitation coated papers such as a clay coated paper, uncoated papers, fabrics, films, glass, ceramics metals or other articles, a non-absorbent paper, a vinyl. In the embodiments that follow receiver 42 is shown in a sheet form, however, continuous web types of receiver 42 can be used.
Although shown as a single endless transport belt 26 in
Control system 20 has a controller 22 that is communicatively connected with a data processing system 30, a peripheral system 32, a user interface system 34, and a communication system 36, a sensor system 40 and a data storage system 44.
Controller 22 can comprise any form of control circuit or system that can perform any of the functions or cause any other component of printing system 10 to perform of the functions described herein. In this regard, controller 22 can include a microprocessor incorporating suitable look-up tables and control software executable by controller 22. Controller 22 can also comprise a field-programmable gate array (FPGA), programmable logic device (PLD), microcontroller, or any other control system or systems capable of performing the functions described or claimed herein.
Data processing system 30 includes one or more data processing devices that implement the processes of various embodiments, including the example processes described herein. The phrases “data processing device” or “data processor” are intended to include any data processing device, such as a central processing unit (“CPU”), a desktop computer, a laptop computer, a mainframe computer, a personal digital assistant, a BlackBerry®, a digital camera, cellular phone, or any other device for processing data, managing data, or handling data, whether implemented with electrical, magnetic, optical, biological components, or otherwise.
In one embodiment data processing system 30 can include a digital front-end processor (DFE). The DFE uses image data and production information to form image data for printing such as rasterized bitmaps or other image types and printing instructions that can be used by inkjet printer 12 or toner printer 16 to determine, respectively, how much ink and toner to deposit at specific locations on a receiver 42 and to determine any required post-processing operations to be performed after inkjet and toner printing. Data processing system 30 can also include a color management system that uses known characteristics of the image printing process implemented in printing system 10 to provide known, consistent color reproduction characteristics for various types of input (e.g. digital camera images, film images, computer generated images).
Peripheral system 32 can include one or more devices configured to provide print order data or components thereof such as image data to controller 22 and to data processing system 30. For example, peripheral system 32 can include digital still cameras, digital video cameras, cellular phones, or other data processors, digital front ends, graphic image servers or computing devices or any other devices that can provide image data and printing instructions to control system 20. Data processing system 30, upon receipt of print order data from a device in peripheral system 32, can store such print order data in data storage system 44.
User interface system 34 can include a mouse, a keyboard, another computer, or any device or combination of devices that can determine when a user has made a user input action and that can convert this user input action into data or other signals that can be used by controller 22, data processing system 30 or any other component of control system 20 in operating printer 10. In this regard, although peripheral system 32 is shown separately from user interface system 34, peripheral system 32 can be included as part of user interface system 34.
User interface system 34 also can also include a display device, a processor-accessible memory, or any device or combination of devices allowing control system 20 to provide output signals to a user of printing system 10. In this regard, if user interface system 34 includes a processor-accessible memory, such memory can be part of data storage system 44 even though user interface system 34 and data storage system 44 are shown separately in
Data storage system 44 includes one or more processor-accessible memories configured to store information, including the information needed to execute the processes of the various embodiments, including the example processes described herein.
Data storage system 44 can be a distributed processor-accessible memory system including multiple processor-accessible memories communicatively connected to data processing system 30 via a plurality of computers or devices. On the other hand, data storage system 44 need not be a distributed processor-accessible memory system and, consequently, can include one or more processor-accessible memories located within a single data processor or device. The phrase “processor-accessible memory” is intended to include any processor-accessible data storage device, whether volatile or nonvolatile, electronic, magnetic, optical, or otherwise, including but not limited to, registers, floppy disks, hard disks, Compact Discs, DVDs, flash memories, solid state or semi-conductor Read Only Memory (ROM), and solid state or semi-conductor Random Access Memory.
The phrase “communicatively connected” is intended to include any type of connection, whether wired or wireless, between devices, data processors, or programs in which data can be communicated. The phrase “communicatively connected” is intended to include a connection between devices or programs within a single data processor, a connection between devices or programs located in different data processors, and a connection between devices not located in data processors at all. In this regard, although data storage system 44 is shown separately from data processing system 30, one skilled in the art will appreciate that data storage system 44 can be partially or completely incorporated with data processing system 30. Further, although peripheral system 32 and user interface system 34 are shown separately from data processing system 30, one skilled in the art will appreciate that one or both of such systems can be partially or completely within data processing system 30.
Control system 20 uses print order data and production information to determine what image is to be printed by inkjet printer 12 and by toner printer 16 and on what receiver 42 the image is to be printed. Further, data processing system 30 is used to help convert image information into image information. In particular, data processing system 30 can include a dedicated image processor or raster image processor (RIP; not shown), which can include a color separation screen generator or generators or a general purpose processor that is adapted to perform raster image processing and other processing described herein.
Control system 20 is illustrated as being apart from ink jet printer 12 and toner printer 16. However, this is for the purpose of illustration only and it will be understood that in general, any components of control system 20 or any functions that are described as being performed by control system 20 can be located in or performed by components that are located in whole or in part in ink jet printer 12 or toner printer 16 or in other process and control devices normally used therewith such as a digital front end or a print server.
For example, in one embodiment, toner printer 16 comprises a modular attachment for ink jet printer 12 and control system 20 can be found largely within a control system located in ink jet printer 12. In such an embodiment, system costs can be reduced by using of control system electronics that are already available in the ink jet printer 12. In an alternate embodiment, toner printer 16 can be capable of performing control and printing functions for ink jet printer 12 so that ink jet printing functionality can be integrated into extant toner printing systems. In one embodiment of this type, such ink jet printing functionality can be inserted into a tandem print module location in a toner printer 16 so as to allow at least one ink jet printing operation to be performed in close proximity to a toner printing operation.
In still other embodiments, overall system costs and complexities can be reduced through the use of an overall control system 20 that performs control functions for both ink jet printer 12 and toner printer 16. In a further embodiment, both ink jet printer 12 and toner printer 16 can be stand alone devices that can directly cooperate to print as described herein such that the functions of control system 20 are shared between control systems and circuits in the individual devices. It will be understood that further variations are possible and that as used herein control system 20 includes any automatic processing circuit, system or structure that can be used to cause an ink jet printer 12 or a toner printer 16 to perform the functions that are claimed.
Inkjet printer 12 forms images on a receiver 42A using an inkjet print engine 70. Inkjet print engine 70 can include a drop-on-demand printhead, either thermal or piezoelectric, or a continuous printhead, using gas, electrostatic, or other deflection methods. The example shown in
In other embodiments, inkjet print engine 70 can use piezoelectric drop-on-demand systems where current is provided to a piezoelectric actuator to cause the actuator to deflect and push an ink drop out of ink manifold 71. In still other embodiments continuous-inkjet systems pressurize the ink in ink manifold 71 to cause a filament of ink to flow from the nozzle and break the filament into drops in a controlled manner, e.g., by selectively heating the ink stream in an appropriate timing sequence. The drops are then selectively directed along a printing path to a guttering system or to form dots on a receiver 42. In gas-deflection systems, two sizes of drops are produced, and an air flow not parallel with the direction of drop travel separates the two sizes of drops. Drops of one size strike the receiver; drops of the other size are caught and reused. Electrostatic-deflection systems charge drops to one of two charge states, and Lorentz forces between the drops and an electrode separate the two sizes of drops.
After ink jet printer 12 records an inkjet image 78 on receiver 42, receiver 42 is advanced to toner printer 16. Toner printer 16 has a toner print engine 110 that arranges charged toner particles 139 into a toner image 138 and transfers the toner image 138 onto receiver 42B having an inkjet image 78 thereon.
In the embodiment illustrated in
In this embodiment, first toner printing module 131 and second toner printing module 132 includes various components. For clarity, these are only shown in first toner printing module 131. As is shown first toner printing module 131 has a photoreceptor 125 and around photoreceptor 125 are arranged, ordered by the direction of rotation of photoreceptor 125, charger 121, exposure subsystem 122, and toning station 123.
An electrostatic latent image is formed on photoreceptor 125 by uniformly charging photoreceptor 125 and then discharging selected areas of the uniform charge to yield an electrostatic charge pattern corresponding to the desired image (a “latent image”). Charger 121 produces a uniform electrostatic charge on photoreceptor 125 or its surface. Exposure subsystem 122 selectively image-wise discharges photoreceptor 125 to produce a latent image. Exposure subsystem 122 can include a laser and raster optical scanner (ROS), one or more LEDs, or a linear LED array.
After the latent image is formed, charged toner particles are brought into the vicinity of photoreceptor 125 by toning station 123 and are attracted to the latent image to develop the latent image into a toner image. Note that the toner image may not be visible to the naked eye depending on the composition of the toner particles (e.g. clear toner). Toning station 123 can also be referred to as a development station. Toner particles 139 can be applied to either the charged or discharged parts of the latent image on photoreceptor 125.
After the latent image is developed into a visible image on photoreceptor 125, receiver 42B is brought into juxtaposition with the visible image. In transfer subsystem 150, a power supply 150a provides a suitable electrostatic field between transfer roller 152 and a pressure roller 154. This field is applied to transfer the toner particles of toner image 138 to receiver 42B to form the desired toner image 138, which includes unfused toner particles, on the receiver, as shown on receiver 42C. The imaging process is typically repeated many times with reusable photoreceptors 125.
Various parameters of the components of a toner printing module such as first toner printing module 131 or second toner printing module 132 can be adjusted to control the operation of printer 16. In an embodiment, charger 121 is a corona charger including a grid between the corona wires (not shown) and photoreceptor 125. Voltage source 121a applies a voltage to the grid to control charging of photoreceptor 125. In an embodiment, a voltage bias is applied to toning station 23 by voltage source 123a to control the electric field, and thus the rate of toner transfer, from toning station 123 to photoreceptor 125. In an embodiment, a voltage is applied to a conductive base layer of photoreceptor 125 by voltage source 25a before development, that is, before toner is applied to photoreceptor 125 by toning station 123. The applied voltage can be zero; the base layer can be grounded. This also provides control over the rate of toner deposition during development. In an embodiment, the exposure applied by exposure subsystem 122 to photoreceptor 125 is control system 20 to produce a colorant attracting toner image 138 corresponding to the desired print image. All of these parameters can be changed.
Further details regarding toner print engines 131, 132 and related components are provided in U.S. Pat. No. 6,608,641, issued on Aug. 19, 2003, to Peter S. Alexandrovich et al., in U.S. Publication No. 2006/0133870, published on Jun. 22, 2006, by Yee S. Ng et al., and U.S. patent application Ser. No. 12/942,420, filed Nov. 9, 2010, by Thomas N. Tombs et al., all of which are incorporated herein by reference.
It will be appreciated that while in the embodiment of
An ink image 78 and toner image toner image 138 deposited on receiver 42C, receiver 42C is subjected to heat or pressure to permanently fix toner image 38 to receiver 42C. Plural print images, e.g. of separations of different colors, are overlaid on one receiver before fixing to form a multi-color fused image 39 on receiver 42C.
Toner printer 16 has a fixing system 60 that fuses toner image 38 to receiver 42C. Transport belt 26 transports a toner-image-carrying receiver 42C to fixing system 60, which fixes the toner particles to the respective receivers 42C by the application of heat and pressure. Receiver 42C is then serially de-tacked from transport belt 26 to and fed into fixing system 60. Transport belt 26 is then reconditioned for reuse at cleaning station (not shown) by cleaning and neutralizing the charges on the opposed surfaces of the transport belt 26.
In the embodiment of
In various embodiments, post printing processing system 18 can provide between additional finishing systems such as those that are known in the art for handling media-handling operations, such as folding, stapling, saddle-stitching, collating, and binding. As discussed above with reference to
In one example, the print order includes image information in the form of image data such as an image data file that control system 20 can use for printing and also contains production information that provides printing instructions that control system 20 can use to determine how this image is to be formed and what receiver 42 is to be used in the printing. In another example, the print order can comprise image information in the form of instructions or data that will allow control system 20 and communication system 36 to obtain an image data file from one or more external devices such as separate servers or storage devices (not shown). In another example, a print order can contain image information in the form of data from which printer controller 82 can generate the determined image for example from an algorithm or other mathematical or other formula. In another example, the image information can include image data from separate data files and/or separate locations, and/or other types of image information. These examples are not limiting and a print order can be received and image information and production information can be obtained using the print order in any other known manner.
Control system 20 then causes transport system 24 to position receiver 42 so that an inkjet image 78 can be recorded thereon (step 306), determines inkjet image data for printing (step 308) and optionally printing instructions and provides the determined image data for printing and inkjet printer 12 to cause inkjet image 78 to be printed on receiver 42 using an inkjet ink that includes a hydrophilic carrier fluid, e.g., water or various low carbon alcohols such as methanol, ethanol, isopropanol, propanol, butanol, isobutanol, and ethylene glycol, in which colorant can optionally be suspended or dissolved. Hydrophilic carrier fluids can be polar. For colorants suspended in the carrier fluid, the suspension can have a zeta potential, as measured using known techniques and commercially available equipment, greater than 160 mV of either sign potential. Conversely, a zeta potential of less than 30 mV is unstable and a zeta potential between 30 mV and 160 mV is semistable. A stable ink containing an aqueous carrier fluid or solvent and suspended pigment particles has a zeta potential whose magnitude is greater than 160 mV.
As is shown in
As is also shown in
Receiver 42 is then positioned for printing by toner printer 16 before unabsorbed volume 406 of drop 77 remaining on the receiver 42 reaches a point where unabsorbed volume 406 is less than about 50 percent of the volume of drop 77.
A toner image 138 conforming to inkjet image 78 is generated (step 314) and transferred to receiver 42 (step 316). This introduces toner particles 139 into unabsorbed volume 406 of drop 77. As is discussed in greater detail above, toner particles 139 are electrostatically charged when transferred. Here, the polarity of the charge on toner particles 139 is arranged to be is the same as that of the water molecules 400. As is shown in
In optional step 317, colorant particles 402 suspended in the carrier fluid (water) are caused to come out of suspension in the carrier fluid (“crash”) after toner particles 139 have been introduced into the unabsorbed volume 406 of inkjet ink 74 on receiver 42, as an additional mechanism to help colorant particles 402 to be deposited on or within toner particles 139. To do this, the zeta potential should be reduced to below 30 mV.
Zeta potentials can be reduced to below 30 mV by dissolving salts into the suspension (i.e., the pigment-containing ink). Such salts include water-soluble salts of alkali and alkali earth and halogens, nitrates, or nitrites such as sodium chloride, sodium fluoride, magnesium chloride, magnesium fluoride, potassium chloride, potassium nitrate, and sodium nitrate. Particles or thin films of these salts can be incorporated onto the surface of the toner particles deposited in step 310. Alternatively, if the toner has an open cell porous structure, salts can be incorporated within the open cells of the porous toner. Open-cell porous toner has larger surface area available to absorb colorant than do solid or closed-cell porous toners. The pigment is brought out of suspension in the carrier fluid before fixing the toner visible image to the receiver (step 318) so that the toner still has a large surface area to receive the pigment as it crashes. Step 317 is thus followed by step 318.
Inkjet image 78 and colorant attracting toner image 138 are fused to receiver 42 to create a print 100 having a generally dried inkjet image 78 and a fused toner image 93 thereon (step 320).
In one embodiment, as is generally suggested in
Additionally, other approaches can be used to address the problems related to fusing toner image 138 that has unabsorbed volume 406 of a liquid ink jet ink 74 therein. Alternatively non-contact fixing can be used. As used herein, such non-contact fixing generally refers to processes that apply energy to cause toner particles 139 to at least in part be heated to a glass transition temperature without requiring that the heat source to directly contact the toner particles. A variety of known non-contact fusing techniques can be used for this purpose.
One example of this is illustrated in
In this embodiment, water 400 in ink 74 has a boiling point that is above a glass transition temperature for toner particles 139 and the liquid in ink 74 heats more rapidly than toner particles 139 in response to exposure to first energy 602. The liquid in ink 74 thus rapidly heats to temperatures above the glass transition temperature of toner particles 139.
Accordingly, while the temperature of toner particles 139 is raised in part by the application of first energy 602, the amount of fusing energy absorbed and converted into internal heat 606 in toner particles 139 is less than that which is required to heat the toner particles 139 to the glass transition temperature. However, when internal heat 606 is combined with heat 608 from water molecules 400 in ink 74 toner particles 139 heat to a temperature above a glass transition temperature for toner particles 139 so that toner particles 139 will bond to each other and to receiver 42 without requiring heating of receiver 42 to the glass transition temperature of toner particles 139.
This liquid enhanced type of non-contact fixing is particularly useful and represents a significant departure from prior art fusing techniques that heat moisture in receiver 42. In one aspect this is because, water 400 or any other liquid on the surface of a receiver 43 does not have to heat through receiver materials to heat toner. Further, water molecules 400 conform to the shape of toner particles 139, and therefore there is a substantial amount of contact area through which they can conduct heat 608 into toner particles 139 in order to cause toner particles 139 to reach the glass transition temperature. These two effects allow non-contact fixing of liquid infused toner images to occur at a much more rapid rate than through the receiver type of non-contact fusing systems. Therefore less fusing energy 602 is required to achieve non-contact fusing of a liquid enhanced toner image 138.
It will be appreciated that the use of this liquid infused non-contact fusing technique provides several other advantages including allowing enabling fixing of a toner image 138 to a receiver 42 while protecting the look and feel of receiver 42 from unintentional modifications that can occur when heated contact surfaces are brought into contact with portions of a receiver 42 that have little or no toner thereon. Further, where such liquid enhanced non-contact fusing is used, spaces between toner particles 139 provide a pathway for vapor to escape from toner image 138 so that pressure does not build within toner image 139. The heating of liquids in ink 74 further helps to enhance the drying process.
Returning to
In one embodiment, control system 20 can use these techniques in different combinations to cause a variety of different effects within a printed image. For example, where a low gloss portion of an image, such as black text is being printed non-contact fusing of a liquid infused toner image can be used, where a higher level of gloss is required, conventional roller fusing can be used, and where a highest level of gloss is to be provided in an image, non-contact fixing can be used in conjunction with contact fusing and glossing. In this regard, it will be appreciated that such liquid infused toner images can be heated in a manner that provides all of the advantages of conventional preheating.
In other embodiments, an optional drying step can be performed before fusing or fixing and can be used to reduce the amount of liquid present in toner image 138 and can warm toner particles 139 to a temperature at or near the glass transition temperature of the toner particles 139 prior to fusing. The heat supplied in such drying can also reduce the possibility that during post processing fusing or sintering the hydrophilic liquid ink that has soaked into the surface of receiver 42 can be brought to a boil. If this happens too quickly for the resulting gas to escape from receiver 42 gradually, the resulting internal pressure in the receiver 42 can puncture part of a thickness of receiver 42 to permit the gas to leave the paper. This can form a blister in receiver 42 that can reduce image quality.
This optional drying step can be performed before fusing, fixing, or sintering and doing so at a lower thermal flux than used for fixing, permits the gas to escape the paper gradually. This reduces the formation of blisters in receiver 42 and also limits the risk that colorant attracting toner image 138 may be modified by vapor pressure.
In one embodiment, the risks of vapor pressure can comprise an additional consideration in determining a colorant attractive toner image, in that the colorant attracting toner image 138 can be defined in a manner that provides avenues 550 for the release of vapor during fusing.
It will be appreciated, that because colorant particles are generally joined to fused toner image 93, and generally do not penetrate into receiver 42, any known process for separating fused toner from receiver 42 can be used to generally de-ink print 100. This permits deinking of print 100 without having to bleach receiver 42 or with substantially reduced inking requirements. This in turn allows a deinkable print 100 to be made according to the methods herein is readily-deinkable and -recyclable and can be made using readily-available hydrophilic inks. Print 100 can be deinked using conventional deinking solvents such as nonpolar organic solvents such as various alkanes and aromatic compounds such as pentane, hexane, octane, heptane, benzene, toluene, xylene, dichloromethane, trichloromethane, tetrachloromethane, 1,1 dichloroethane, 1,2 dichloroethane, 1,1,2 trichloroethane, and 1,1,1 trichloroethane. In various embodiments, deinkable materials are deposited only in the inked areas, and not in the noninked areas. This saves material compared to flood-coating a receiver with an ink-absorbent material. It also permits a viewer of the print to perceive the physical, textural, and visible attributes of the paper, which attributes a flood-coat would mask. Various embodiments permit the printer to produce prints with different perceived characteristics by, e.g., applying texture or gloss, applying an image-specific protective coating, or applying a UV or other fade-preventive overcoat. These effects and characteristics can be applied to the printed region without changing the characteristics of the paper in unprinted areas. In one embodiment, the transfer of the toner particles into the ink jet ink is performed in the presence of an electrostatic field so that the electrical charge on the toner to further urge the colorant to toner particles 139. However, this electrostatic field must be less than an amount that would cause the toner to separate from the receiver 42.
In another embodiment, the toner particles 139 can have an open cell structure. In an open cell porous toner particle 139, voids within toner particle 139 are interconnected and can be connected to the surface of the toner particle 139 to permit surrounding air, liquids or other mediums to enter or pass through the toner particles. The presence of interconnectivity can be determined by either microtoming porous toner particles and examining in a transmission electron microscope (TEM) the cellular structure. Alternatively, BET can be used to determine whether a porous toner has an open or closed cell structure. Specifically, the surface area per unit mass of open cell porous toner particles 139 is greater than that of non-porous toner particles 139 because the porous toner particles 139 are less dense. Thus, the density of a porous toner particles 139 is determined by measuring the volume of a known mass of toner and comparing that to the volume of an equivalent mass of toner of comparable size and polymer binder material. The surface area per unit mass is then measured using BET. For a closed cell porous toner, the surface area per unit mass would be approximately the same as that of the nonporous toner times the ratio of the mass densities of the nonporous and porous toners.
It will be appreciated that open cell toner particles 139 can advantageously provide substantially more surface area than non-porous toner and also require less binder material than conventional toners, such that less thermal energy is required to fuse such open cell toner particles. Further, it will be appreciated that open cell porous toner particles provide liquid inkjet ink 74 from unabsorbed volume 406 a greater number of pathways along which to travel and therefore offer many more pathways for inkjet ink 74 to follow which provide a greater opportunity ensure that colorant particles 402 are positioned within toner particles 139 of a colorant attracting toner image 138 which further enhances the recyclability of a print 100 having such toner particles thereon.
In one embodiment, generally illustrated in
In step 710, an inkjet image is jetted onto a water-absorbing receiver (e.g., uncoated or porous papers, including bond papers and calendared papers) to produce an ink jet image. The inkjet ink has a carrier fluid comprising a polar solvent such as water or low-carbon-chain alcohols, i.e., alcohols containing four or fewer carbons such as methanol, ethanol, propanol, butanol, and ethylene glycol. Step 720 is followed by step 730.
In step 720, a colorant attracting toner image is transferred are image-wise deposited a colorant-absorbing particulate image. In various embodiments, the colorant-absorbing toner is colorless (“clear”) and has an open-cell porous structure. Step 720 is followed by step 730.
In step 730, at least some of the polar solvent is removed from the colorant-absorbing particulate image. This separates the colorant from the hydrophilic liquid and entraps the colorant into a material that is soluble in a hydrophobic organic solvent. This can be accomplished by passing gas through the colorant-absorbing ink image, applying a vacuum to the non-image-bearing side of the receiver, or heating the ink using noncontact heating methods such as those described above. Alternatively, the non-image bearing surface of the receiver can be brought into contact with a hot surface such as a heater to evaporate the solvent. If the solvent is evaporated, the toner should not be permitted to fuse, but can be permitted to tack to create a porous toner mass, as described above. Step 730 is followed by step 740.
In step 740, the colorant-absorbing particulate image is fused to the receiver, e.g., as discussed above with reference to fixing system 160 (
Toners useful with various embodiments include those with thermoplastic polymer binders such as polyester and polystyrene. The toners should not be thermoset materials, and should not cross-link or change from a thermoplastic to a thermoset, e.g., with exposure to UV radiation, heat, or time. Using non-thermoset toners provides increased solubility of toner in organic solvents commonly used for deinking printed papers. In various embodiments, the polymer binder has a glass transition temperature between 45° C. and 70° C., or between 50° C. and 58° C. In one embodiment, toner particles 139 use a binder which is a thermoplastic that is soluble in a non-polar organic solvent.
In various embodiments, the colorant-attracting toner particles are stained by the colorant (the colorant can be a dye or a pigment). In an example, the colorant is a dye dissolved in the solvent of the ink, and the dye separates from the ink by staining the toner. The toner can be polyester, which can be readily stained by a wide variety of dyes. In various embodiments, the toner does not include polystyrene or polystyrene acrylate, since those materials can be stained by only a limited number of dyes having specific pH levels.
In still another embodiment, a toner image can have toner particles that are made from, are coated with or have addenda thereon that absorbs ink at a faster rate than the receiver. The faster rate can be as much as 10 times greater than that of the receiver 42 creating a flow of liquid drawing the colorants against the toner.
In various embodiments, the polar solvent is removed from the colorant-absorbing particulate image by absorption of the solvent by the receiver, followed by subsequent drying of the receiver. In these embodiments, the receiver can be a receiver that does not contain a clay coating or polymer coating on the surface. The receiver can be dried by conductive, convective, or radiant heating, by pressure, or by combinations of those.
In step 850, a hydrophobic or oliophilic organic solvent is applied to print 110, so that a majority of the toner image is separated from the image-bearing member. As toner from fused toner image 93 is removed from receiver 42 on which it has been formed, colorant particles are likewise is removed from receiver 42. As a result, a deinked reflection density of the image-bearing member in a selected test area from which the toner image layer was dissolved is within 0.15 of an unprinted reflection density of the image-bearing member before deinking. The unprinted reflection density is the average density of the paper without any colorant thereon.
Various components of printing system 10 have been or described herein as belts or rollers; however as is known in the art, other configurations are possible including but not limited to configurations where rollers perform functions that are shown as being performed by or where belts perform the function illustrated as being performed by rollers. Further, any other known mechanism for controllably conveying a receiver can be used.
The invention is inclusive of combinations of the embodiments described herein. References to “a particular embodiment” and the like refer to features that are present in at least one embodiment of the invention. Separate references to “an embodiment” or “particular embodiments” or the like do not necessarily refer to the same embodiment or embodiments; however, such embodiments are not mutually exclusive, unless so indicated or as are readily apparent to one of skill in the art. The use of singular or plural in referring to the “method” or “methods” and the like is not limiting. The word “or” is used in this disclosure in a non-exclusive sense, unless otherwise explicitly noted.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations, combinations, and modifications can be effected by a person of ordinary skill in the art within the spirit and scope of the invention.
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