EP1307787B1 - Device and method for fixing a toner image using a directed stream of solvent vapour - Google Patents

Abstract

In a vapor fixing device for an electrographic printer or copier, the heated vapor housing is provided such that vapor does not condense at the interior housing walls. A directed stream containing solvent vapor is produced which is directed at a section of the support material.

Description

The invention relates to a device and a method for fixing a toner image on a substrate, in which the toner image is exposed to a solvent vapor becomes. Furthermore, the invention relates to a device for printing and / or copying, in which such Device is used.

In a variety of electrophotographic printing or Copying is done on a substrate, for example Paper, a toner image transferred, not at first smudge-proof and abrasion-resistant connected to the carrier material is. Only by a fixing process is achieved that the Toner image firmly bonded to the substrate, i. fixed becomes. Usually a fixing process is used in which the toner is subjected to heat and pressure. Here, the toner is using heated fuser rollers melted and pressed into the carrier material, so that the toner forms an adhesive bond with the carrier material. This heat-pressure fixation is, if not special Paper preheating is carried out in the transport speed limited the carrier material, for example to about 0.5 m / s to 0.7 m / s.

When the substrate is in duplex printing mode Both sides will be printed simultaneously and both sides must be fixed at the same time, so must both sides Fuser rollers are used, which are soft and yielding are. Such fixing rollers have only a short life and come because of the low cost only in printers or copiers with low print volumes for use. Furthermore, due to the compliance the fixing rollers, the leadership of the substrate problematic so that in such a fixing method a endless carrier material web are used only conditionally can.

Contactless fixing methods have already been proposed. the by the contact between substrate and Dividing the fixing device, e.g. the fuser rollers, resulting Avoid problems.

From EP-A-0 629 930 an arrangement is known in which Toner melted by infrared radiation and on is fixed to the paper. Such an arrangement can also used in duplex printing, with both sides simultaneously fixed toner images on the substrate become. The infrared emitters used have and turn off a relatively large time constant, so that with such an arrangement a start / stop operation without Waste paper or committee can not realize.

From DE-A-198 27 210 an arrangement is known, in which also uses infrared radiation for fixing becomes. By the targeted control of a roller blind, which in inserted the beam path of the infrared radiation and can be moved out again, a start / stop operation can be realized without rejects. However, the general remains Disadvantage of fixing with infrared radiation, which is that the carrier material, in general Paper, relatively dry during fixing what will cause a shrinkage, ripple and in a further and post-processing of the carrier material leads to an electrostatic charge. Such Changing the substrate can cause significant problems during the post-processing of the carrier material, for example, when cutting, stacking, binding, inserting, Etc..

Another known contactless fixing method is the Flashlight fixation, when using high-energy light pulses the toner is fixed on the carrier material. The Wavelength of the radiation is generally in the visible to the ultraviolet region of the radiation spectrum. The flash fixation is sensitive to the color of the toner, i. The toner material absorbs the energy depending on the available light spectrum, resulting in quality losses when using toners of different colors, for example, in multi-color printing, can lead.

Another contactless fixing method is the so-called Cold fixation. In this cold fixation, the toner material softened under the influence of a solvent. The softened toner wets the carrier material. at the use of carrier material containing fibers, such as For example, paper or textiles, the softened encloses Toner the fibers and penetrates partly due to Capillary forces between the fibers and in this one. To the evaporation of the solvent solidifies the toner again and solidifies. This will wipe the toner. and abrasion resistant bonded to the substrate. The presence the solvent in vapor form is in the fixing process more advantageous than the presence as an aerosol or liquid, because chemical dissolution processes on a molecular basis run off and a molecular distribution of the solvent thus most suitable. It also finds use of steam due to the different temperatures of Support material and steam condensation of the solvent vapor on the toner particles, so that the Deposit vapor molecules directly on these toner particles. In addition, the delivery promotes the enthalpy of vaporization in the condensation the softening of the toner and increases the speed of the dissolution process.

A general advantage of fixation using a solvent is the low thermal load of the carrier material. Accordingly, carrier materials can be used the only one low thermal or mechanical Withstand load, such as Labels and foils. Furthermore the moisture content of the carrier material is not changed, so that caused by moisture changes Ripple, a dish or a curling is avoided. In addition, the cold fixation is largely independent of the thickness of the support material, so that without much change the fixing process, for example, papers with different Paper thicknesses can be used. On This way can also change the paper type at low Effort made.

From US-A-4,311,723 an arrangement is known in which a paper web through a fixing chamber with solvent vapor to be led. The solvent vapor is in a container. Due to gravity and cooling tubes in the upper part of the container, the concentration decreases the solvent vapor to the container bottom towards, so that in the vicinity of the container bottom an area with a high solvent concentration arises. The carrier material, with the still unfixed toner images in the upper Area of the container enters, is at a first deflection turned down and in the area the high solvent concentration in the vicinity of the container bottom guided. There is the carrier material with partial fixed toner images on a second deflection device redirected again and finally over one third deflection out again led up out of the container. At the deflectors necessarily takes place a contact of the carrier material instead, whereby the toner on it will smear or peel off can or will leave pressure marks. With This arrangement is therefore not possible double-sided To fix with toner images acted upon carrier material. In addition, the arrangement shows a relatively slow Start / stop behavior because stopping the fixation Deflection device from the range of high solvent concentration out up into an area with one low solvent concentration at which fixation no longer takes place, must be driven, what a predetermined Time is needed.

The use of solvents can be problematic with regard to the formation of ozone. In this context, the ozone potential of a solvent is spoken. In the mentioned US-A-4,311,723 an azeotropic mixture of trichlorofluoroethane (C ₂ Cl ₂ F ₃ , CFC113, English CFC113) and acetone (C ₆ H ₆ O) is used as the solvent. The primary solvent is the acetone, while the CFC113 serves as a flame retardant. Due to the high ozone potential, the use of CFCs113 was banned at the beginning of the nineties. As a replacement for the CFC113 then semi-halogenated hydrocarbons, so-called HCFCs (English HCFC) have been proposed, for example HFCKW123 and HCFC141b, as they have a much lower ozone potential. From now on, these hydrocar- bons HCFCs have taken over the function of the flame retardant in mixtures of air and flammable solvents, such as acetone, propanols, etc. When using polystyrene-based toners, the use of pure HCFC141b in particular without the addition of a solvent, such as acetone , Has proven to be advantageous because HFCKW141b has a sufficient fixing effect for these toners and is easy to recover as a single-phase material, since no mixing or separation problems occur.

However, HCFC141b is also due to its ozone potential and the associated environmental impact only still limited time available. Therefore, on the Basis of chlorine-free, fully halogenated hydrocarbons HFC (new HFC) proposed new fixative mixtures, For example, in EP-A-0 784 238 (Appl Solvay) and EP-A-0 941 503 (Applicant Allied Signal). at the polyester-based material commonly used today Toners, however, these mixtures have in practice proved to be problematic in the application.

From EP-A-0 613 572 there is a method and a solvent for fixing a polystyrene-based Toners known. As the sole solvent becomes partially halogenated fluorohydrocarbon having a boiling temperature used below 35 ° C.

From DE-A-2 720 247 a printing process is known at the toner from an intermediate carrier, e.g. a photoconductor drum, at a transfer station to a recording medium is transmitted. The toner on the photoconductor drum is acted upon by a solvent vapor such that he gets sticky. Likewise, the record carrier, e.g. Paper exposed to solvent vapor. The sticky one Toner adheres to the solvent also provided Paper, which in a single process of the transfer process and the fixing of the toner takes place.

DE-A-197 55 584 A1 describes a fixing process for Fix toner images on paper. For contactless Fixing is hot gas with a predetermined proportion Used steam.

From DE-A-2 613 066 there is also a fixing device in which the toner material of the toner image on the Record carrier with a hot gas, in particular Air, is applied. The temperature of this gas is such that the toner melts and enters the record carrier, e.g. Paper, penetrates.

CH,A,457 144; US,A,3 680 795; Cut-Sheet Vapor Fuser", IBM Technical Disclosure Bulletin, IBM Corp. New York 32(3A), 1989, 258-259, XP000049471; DE,A,29 27 453; DE,A,36 36 324.

The international search report mentions the following documents:

CH, A, 457 144; US, A, 3,680,795; Cut Sheet Vapor Fuser ", IBM Technical Disclosure Bulletin, IBM Corp. New York 32 (3A), 1989, 258-259, XP000049471; DE, A, 29 27 453; DE, A, 36 36 324.

The independent claims are based on the state of the art CH, A, 457 144.

It is an object of the invention to provide a device and a Indicate the method, the or at low environmental impact with high efficiency a fixation of toner images allows. This task is for a device solved by the features of claim 1. According to others Aspects of the invention will be an apparatus for printing or copying specified using the said device. In addition, a method for fixing toner images specified.

Figur 1

eine bekannte Fixiervorrichtung mit weitgehend ruhendem Lösungsmitteldampf,

Figur 2

den Aufbau einer inerten Luftschicht zwischen der Papierbahn und dem Lösemitteldampf,

Figur 3

den Effekt einer Lösemittelverarmung,

Figur 4

das erfindungsgemäße Prinzip des Anströmens des Trägermaterials mit einem gerichteten Strom,

Figur 5

schematisch den Aufbau einer Fixiervorrichtung nach der Erfindung,

Figur 6

ein bevorzugtes Ausführungsbeispiel der Erfindung, bei dem das Trägermaterial von oben und von unten angeströmt wird,

Figur 7

ein Ausführungsbeispiel, bei dem das Gegenstromprinzip realisiert ist,

Figur 8

die Erzeugung des gerichteten Stroms durch Expansion des verdampfenden Lösemittels,

Figur 9

eine vereinfachte Variante nach Figur 8,

Figur 10

ein Beispiel mit Verdampferkammern, die außerhalb der Fixierkammer angeordnet sind,

Figur 11

ein Ausführungsbeispiel, bei dem das Trägermaterial nur von einer Seite mit einem gerichteten Strom beaufschlagt wird,

Figur 12

das Beispiel nach Figur 11, jedoch mit realisiertem Gegenstromprinzip,

Figur 13

zwei hintereinander geschaltete Fixierkammern,

Figur 14

das Beispiel nach Figur 13, wobei in einer Kammer das Gleichstromprinzip und in der anderen Kammer das Gegenstromprinzip realisiert wird,

Figur 15

zwei hintereinander geschaltete Kreisläufe mit Lösungsmitteldampf in einer einzigen Kammer,

Figur 16

eine Ausführungsform, bei der das Trägermaterial vertikal durch die Fixierkammer geführt ist,

Figur 17

ein Ausführungsbeispiel, bei dem das Trägermaterial unter einem Winkel von 45° durch die Fixierkammer geführt ist,

Figur 18

das Ausführungsbeispiel nach Figur 6, wobei die Steuerklappen in die Umlenkstellung geschwenkt sind, und

Figur 19

ein Ausführungsbeispiel mit weiteren Steuerelementen.

Embodiments of the invention will be explained below with reference to the drawing, wherein reference is also made to known fixing devices. In the figures shows:

FIG. 1

a known fixing device with largely quiescent solvent vapor,

FIG. 2

the construction of an inert air layer between the paper web and the solvent vapor,

FIG. 3

the effect of a solvent depletion,

FIG. 4

the inventive principle of the flow of the carrier material with a directed stream,

FIG. 5

schematically the structure of a fixing device according to the invention,

FIG. 6

A preferred embodiment of the invention, in which the carrier material is flowed from above and from below,

FIG. 7

an embodiment in which the countercurrent principle is realized,

FIG. 8

the generation of the directed stream by expansion of the evaporating solvent,

FIG. 9

a simplified variant of Figure 8,

FIG. 10

an example with evaporator chambers, which are arranged outside the fixing chamber,

FIG. 11

an embodiment in which the carrier material is acted upon by only one side with a directed current,

FIG. 12

the example of Figure 11, but with realized countercurrent principle,

FIG. 13

two fusing chambers connected in series,

FIG. 14

the example of Figure 13, wherein in a chamber, the DC principle and in the other chamber, the countercurrent principle is realized,

FIG. 15

two successive circuits of solvent vapor in a single chamber,

FIG. 16

an embodiment in which the carrier material is guided vertically through the fixing chamber,

FIG. 17

an embodiment in which the carrier material is guided at an angle of 45 ° through the fixing chamber,

FIG. 18

the embodiment of Figure 6, wherein the control flaps are pivoted into the deflection position, and

FIG. 19

an embodiment with further controls.

Figure 1 shows the structure of a conventional fixing device similar to that of the already mentioned US-A-4,311,723. To the embodiments of the invention better to understand, should first on this known fixing device To be received. In a container 10 is generates a solvent vapor 12. Within the container 10th Cooling tubes 16 are arranged, which cool the solvent vapor. Accordingly, the solvent concentration in the upper Area 18 is lower than in a middle area 20 and there again lower than in the ground area 14. The highest Solvent concentration is therefore in this soil area 14 can be found. The carrier material 22, in general a paper web, with still unfixed toner images enters horizontally into the container 10 and is at a first deflecting device 24 deflected vertically downwards and in the range of high solvent concentration in the soil area 14 led. The toner images are going this way the paper web 22 partially fixed. The paper web 22 is deflected at a second deflection device 26 again and finally via a third diverter 28 led out of the container 10 again.

At the deflectors 24, 26 and 28 necessarily takes place a contact of the paper web 22 with the deflecting elements instead of. Because of this touch, especially on the elements 24 and 26, the toner may smear or peel off, and / or on the paper web 22 can pressure points be left behind. A double-sided simultaneous Fixation of toner images on both sides of the paper web 22, as for example in the operating mode Duplex printing would be necessary is not possible because the toner on the back already at the first deflection 24 would be blurred. In addition, could the still soft toner on the third deflection device 28th be partly replaced again.

Furthermore, the device shown in Figure 1 a relatively slow start / stop behavior on when the paper web 22 is stopped during forward transport or resumes its transport speed. To stop the fixing process is namely the deflection 26 from the area with high solvent concentration, the Floor area 14, out up into the upper area 18 operated with low solvent concentration, in the the fixing process is greatly reduced. The movement takes a relatively long time and thus determines the dynamic behavior of the entire fixation device.

FIG. 2 schematically shows an effect due to the Movement of the carrier material 22 is formed. Generally is too mention that preferably paper is used as carrier material 22 becomes; however, other materials such as For example, films, labels or plastics used become. With a movement of the paper web 22 in the direction of the arrow P1 becomes air 30 from outside the fixing device taken. This air 30 is located as inert layer between the paper web 22 and the solvent vapor 12, whereby the fixing process is slowed down since the solvent vapor 12 first penetrate the air layer 30 got to. This effect depends on the transport speed the paper web 22 and the spatial geometry the fixing device. At quiescent solvent vapor 12 this effect is especially big.

FIG. 3 shows a further effect which is particularly apparent in FIG dormant solvent vapor 12 occurs. The temperature of the Paper web 22 is generally below the boiling point of the solvent so that on the surface of the paper web 22, the solvent vapor 12 condenses. In a Zone 32 near the surface of the paper web 22 enters Solvent depletion, so that the surface of the paper web separated from the highly concentrated solvent vapor 12 is and the toner can not be solved further.

Figure 4 shows the principle used in the invention. The surface of the support material, e.g. the paper web 22, by means of a directed stream, the solvent vapor 12 contains, flowed. The stream 34 emerges from a Nozzle 36 off. The stream 34 of solvent vapor 12 penetrates the inert air layer 30 and enters an area 38 of the paper surface to release the toner.

The strong convection generated by the flow increases the likelihood of solvent molecules during the Lead time of the paper web 22 through the fixing device with the toner particles and the toner to solve. The stream 34 is composed of a mixture of air and solvent vapor together. The Zohe shown in Figure 3 32 with solvent depletion may be due to convection do not train, as continuously new solvent vapor 12 is supplied. At the Anströmstelle 38 is thus always maintain a high solvent concentration. This approach principle causes even at a low chemical dissolving power of the solvent sufficient dissolving effect is achieved and the required exposure time reduced. By reducing this exposure time can at a given paper speed the size the fixing device are reduced, or it can the paper speed at a given size increase.

Figure 5 shows schematically the structure of a fixing device according to the invention for a simultaneous double-sided Fixation of toner images on the carrier material 22. The fixing device comprises a fixing chamber 40, which has a essentially closed construction has to avoid that the effective solvent vapor is mixed with ambient air diluted. The carrier material 22, in general a paper web passes through the fixing chamber 40 straight and horizontal, with a first narrow entrance slit 42 and a narrow opposite this Exiting gap 44 passes. The entrance slit 42 is designed so that between it and the substrate 22 even with a flutter or sagging of the web No contact occurs to the on the substrate 22 on both sides located toner image not to blur. If the operating mode "Simplexdruck" with only one-sided Toner images applied to the substrate 22 can be on the opposite side of the toner images Side of the substrate 22 take place a touch and it may be arranged corresponding guide elements become.

Due to the friction between ambient air and carrier material 22 is due to the transport movement of the carrier material 22 air in the area of a boundary layer taken. Upon entry of the carrier material 22 in the fixing chamber 40 is therefore through the entrance slit 42 through ambient air with transported into the fixing chamber 40 inside. On the exit side is due to the movement of the carrier material 22 solvent vapor from the interior of the fixing chamber 40 through the exit slit 44 therethrough entrained outside. These effects will increase the solvent concentration steadily lowered inside the fixing chamber 40, if this effect is not counteracted. Around to reduce this effect, on the one hand, the entrance slit 42 and the exit slit 44 as close as possible performed; on the other hand, during the fixing process continuously fresh solvent vapor from an evaporator nachgefördert in the fixing chamber 40.

FIG. 6 shows a preferred embodiment of the invention, at the toner images on both sides of the substrate 22 are fixed. The fixing device is constructed symmetrically to the carrier material web 22. Hereinafter Components are explained for fixation the existing on the upper side of the substrate sheet 22 Toner images are needed. This description applies also according to the components for the fixing process on the lower side of the substrate 22. Within the fixing chamber 40, an evaporator 46 is arranged, the fed via a feed tube 48 liquid solvent becomes. The solvent drips onto a heated plate 50, whose temperature is above the boiling point of the solvent is, for example, 30 ° C above the boiling point. To improve the evaporation process can the plate 50 roughened chemically or mechanically or with Be provided grooves. The generated vapor stream 52 escapes via an opening 54. This opening 54 can be used as a slot or be designed as a nozzle. In a preferred embodiment is the opening 54 as a valve, preferably as a solenoid valve, formed. Through targeted clocked Opening and closing the valve can prevent the leakage the steam flow 52 are controlled.

Alternatively, the addition of the solvent can also help a nozzle. This nozzle (not shown), produces a finely atomised jet of solvent, which is sprayed onto the heated plate 50.

The escaping from the evaporator 46 vapor stream 52 is the suction side of a cross-flow fan 56 supplied as the Radial fan is formed. The crossflow fan 56 can be adjustable in its speed to the stream 34 from a Mixture of air and solvent vapor in his Adjust flow rate. The stream 34 is using the slotted nozzle 36 obliquely in the transport direction P1 of the carrier material 22 is directed onto the carrier material 22. The directed stream 34 is then along a channel 58 guided along the carrier material 22 and at the end of the Suction channel 58 from the crossflow fan 56 to again with fresh vapor stream 52 mixed to a directional Stream 34 to be compressed. The flow velocity of stream 34 is generally a multiple the transport speed of the carrier material 22. Auf this way, the same part of the stream 34 can be mixed with the solvent vapor within a contact time, by the length of the channel 58 and the transport speed is defined several times on the toner images on the substrate 22 act.

The responsible for the dissolution of the toner material solvent vapor is in a cycle under steady Circulation of the solvent vapor the toner material in the Supplied toner images. Due to the constant upheaval of the solvent is a homogenization of the solvent concentration within this cycle and therefore one Homogenization of the fixation of the toner images on the Carrier material 22 causes .. By the flow of the carrier material 22 with a directed current 34 is the fixing process accelerates, so that a lower solvent concentration sufficient for fixing, or solvent can be used with reduced release force.

According to the embodiment of Figure 6 generates the Slit nozzle 36 an obliquely impinging on the carrier material 22nd Electricity 34. Due to the inclination of the Slit nozzle 36 is in the region of the entrance slit 42 a Low pressure or a constant pressure produced. By a skillful choice of the angle of attack of the slit nozzle 36 may so the entry of air due to the transport movement of the Support material 22 are minimized.

In the example of Figure 6 are components of the directed Stream 34 and the transport direction P1 rectified. Such an arrangement is referred to as DC principle. The arrangement can also be designed so that Components of the stream 34 and the transport direction P1 are opposite each other. This arrangement is countercurrent principle called.

If the substrate 26 only on one side, for example the upper side, wearing toner images, so can on the Components for fixing toner images of the lower Side are omitted, i. on the below the substrate arranged in Figure 6 components, such as Evaporator, the cross-flow fan etc.

The arrangement of Figure 6 may be designed so that Flammable solvents can be used in the context of the explosion protection device safety measures require. So is an explosion flap 60 in Arranged portion of the exit slit 44, located at increased pressure opens. The substrate 22 is using an unloading device 62 by means of ionized air electrostatically discharged. Within the fixation chamber 40 all sources of ignition avoided. All parts of the device are grounded to avoid static electricity. In near the entrance nip 42 and the exit nip 44 is in each case a suction device 64, 66 effective, the in small quantities escaping from the fixing chamber 40 Solvent vapor sucks. Accordingly, outside the Fixing chamber 40, even with prolonged operation no harmful or explosive solvent vapor concentrations occur.

The arrangement of Figure 6 is also for a fast Start / stop behavior designed. For this purpose are two control flaps 70, 72 provided, which in Figure 6 in the release position are drawn. In this position, the Stream 34 flow freely. Both control flaps 70, 72 can in a deflection position according to the pivoting directions P2, P4 are pivoted so that the carrier material 22 is not more is supplied with solvent vapor. For immediate Interrupt the fixing process, the control flaps 70, 72 controlled in the deflection position. simultaneously becomes the inflow of solvent via the feed tube 48th stopped for the evaporation process and it becomes the suction device 66 switched off. The other suction device 64 then sucks fresh air into the fixation chamber 40 and the channel 58 and thus the area around the substrate 22 is flushed with fresh air. Through this Measures the fixation process is abruptly interrupted.

Upon resumption of printing operation and onward transport of the carrier material 22, the fixing process by Swiveling the control flaps 70, 72 against the directions P2, P4 started again. At the same time, the suction device 66 reactivated and the solvent inflow started for the evaporator 46.

In certain printing processes, the carrier material 22 before resuming printing in the direction of Printing unit, opposite to the direction P1, withdrawn. In this case, the control flaps 70, 72 only then folded back into its release position when on the Anströmstelle in the channel 58 again unfixed toner images are located. Thus it is achieved that already fixed Toner images do not go through a fixation process again.

In the circuit with solvent vapor is a sensor 74th switched, which measures the solvent concentration. As will be explained in more detail below, using this sensor 74, the solvent concentration on a constant value regulated.

When feeding solvent into the circuit for Solvent vapor and in the leadership of the solvent vapor in the cycle it is to be ensured that at no Make up larger solvent droplets by condensation, which could fall on the substrate 22. Out For this reason, in the fixing chamber 40, all the walls, which come into contact with the solvent vapor, heated. The temperature of these walls is adjusted so that they at least.the boiling point of the solvent has or above it.

Figure 7 shows an example of a fixing device similar according to FIG. 6. However, the countercurrent principle is realized here, i.e. the stream 34 with solvent vapor is opposed the transport direction P1 of the carrier material 22 directed.

FIG. 8 shows another variant of the invention. At this Variant is the expansion of the evaporating solvent used to generate a directed current 34, contains the solvent vapor. The evaporator 46 is over the feed tube 48 is supplied with liquid solvent. The Nozzle 36 generates the directed stream 34, which is the carrier material 22 flows to. The flow velocity and the Volume flow depends on the evaporated amount of solvent. Again, preferred as a nozzle 36, a slit nozzle used. However, it is also possible, as well as this for the other examples, the solvent vapor is off several small round nozzles that are across the width of the Support material 22 are mounted to flow out. In the example of Figure 8, the carrier material 22nd not repeatedly flown by means of a vapor flow circuit.

FIG. 9 shows a further variant of a fixing device according to the invention, in which due to the expansion in the evaporation of the solvent, a directed stream 34 is generated. This stream 34 is only once on the Carrier material 22 steered. The variant according to FIG. 9 is for low transport speeds of the carrier material 22 suitable.

FIG. 10 shows a further variant in which the evaporator 46 is disposed outside of the fixing chamber 40. The Opening 52 is slit-shaped and is located nearby of the crossflow fan 56 on its suction side. The opening However, 54 may also have other embodiments. Of the Introductory point for the live steam in the circuit can in general terms, anywhere in the cycle are located.

FIG. 11 shows an exemplary embodiment of simplex printing. The fixing process with the directed current 34 is effective only on one side of the substrate 22. At the Example according to FIG. 11 the DC principle is applied, in which the stream 34 in the direction P1 of the transport of the carrier material 22 extends.

FIG. 12 shows the example according to FIG. 11 with counterflow principle, wherein the stream 34 is opposite to the transport direction P1 is on.

Figure 13 shows an example in which two circuits with Streams 34a and 34b are generated sequentially. Both Currents 34a, 34b act on the same side of the carrier material 22 on. The streams 34a and 34b become two consecutive switched fixing chambers 40a, 40b generated. In Both chambers 40a, 40b, the synchronization principle is applied.

Figure 14 shows a similar example as Figure 13. In the Chamber 40a becomes the DC principle and in the chamber 40b applied the countercurrent principle.

FIG. 15 shows another example similar to that of FIG 14, but with the streams 34a and 34b in a single Fixing chamber 40 are generated. The combined DC / countercurrent principle according to example of FIG 14 is retained.

FIG. 16 shows an embodiment in which the carrier material 22 is guided vertically through the fixing chamber 40. Due to the forced flow, the fixation process is general expressed independently of the transport direction of the carrier material. In this way, increased results Degrees of freedom in construction and inclusion the fixing device in a printer or copier.

FIG. 17 shows an example in which the carrier material 22 at an angle of about 45 ° through the fixing chamber 40 is guided.

Figure 18 shows the embodiment of Figure 6, wherein the control flaps 70 and 72 pivoted into the deflection position are. Using these control flaps 70, 72 is the current 34 is deflected so that the carrier material 22 is not more is streamed. At the same time, the inflow of solvent stopped in the evaporator 46 and the suction device 66 switched off. The continuing working suction 64 then sucks fresh air into the fixation chamber 40, whereby the carrier material 22 is flushed with fresh air becomes. These measures make the fixing process abrupt interrupted. To resume the fixing operation the control flaps 70, 72 swung back into a Position, as shown in Figure 6. simultaneously the suction device 66 is turned on and the Solvent inflow into the evaporator 46 started.

FIG. 19 shows the fixing device according to FIG. 6 with further Controls. Due to the not completely preventable steady entry of air into the fixation chamber 40 by the movement of the substrate 22 must during the fixing operation constantly solvents are nachgefördert, to maintain the solvent concentration. For detecting the solvent concentration serve the Sensors 74a and 74b, the concentration once above of the carrier material 22 and another time below the Capture carrier material 22. The signals from the sensors 74a, 74b go to regulators 80a, 80b, which are on solenoid valves 76a, 76b acting in the supply lines 82a, 82b for the solvent is switched. In the open state of Solenoid valves 76a, 76b passes solvent from a Reservoir 78 to the evaporator chamber 46a, 46b. The regulators 80a, 80b represent the opening times of the solenoid valves 76a, 76b such that the solvent concentration in the Current 34a and 34b has a constant value.

With reference to the described embodiments should again the advantages of the fixing device according to the invention be summarized. Using the fixing devices shown Is it possible to contactless toner images on the Fix carrier material. The toner image and also the Carrier material, such as sensitive paper, be not damaged and no pressure points and no detachment or squeezing of the toner. Further eliminates wearing parts, such as in shape the fixing rollers in the heat-pressure fixation required are.

Using the fixing device is an intermittent Work possible because of a quick start / stop operation can be realized. The size of the fixing device is compared to conventional fixators and comparable transport speeds, for example Transport speeds greater than 1 m / s, relatively small. Due to the circulation of the solvent vapor and the directed Strom is achieved a very homogeneous fixation.

By the flow of the carrier material with solvent vapor and in particular by the circulation principle becomes the Fixing improved, so that less solvent at reduced consumption is needed. Likewise, an environmentally friendly Solvent with reduced solvent power be used, the transport speed is high may be, i. greater than 1 m / s. The strength of the softening of the toner material may be due to the solvent concentration be influenced in the fixation chamber. So can the degree controlled by the penetration of the toner into the paper. For special requirements, such as increased document security, is it with the fuser after the invention possible, such a strong penetration of the Toners in the Trägermtaerial to reach that toner only with great effort or not at all from the carrier material can be removed again.

In the specified fixation fixation is largely regardless of the thickness of the carrier material; e.g. Thin and thick papers can be processed. Due to the prevailing at the cold fixation low Temperature results in a low thermal load, so that heat-sensitive carrier materials, such as. Sheets and label can be used.

When fixing in the fixing chamber, the carrier material heated only slightly, so that it does not dehumidify or hardly dehumidifies becomes. This prevents moisture changes and adverse effects such as ripples, dishes or curling of the carrier material do not occur. With the help of Fixing devices described may toner different Colors are fixed at the same time.

The fixing device allows preferably halogen-free Solvents can be used, such as Ethyl acetate, acetone, isopropanol, n-propanol. The Solvent may be single-phase, causing condensation and preparation of emerging from the fixing chamber and extracted solvent vapors during recovery are very simple. Through this recovery and Reuse of the solvent can reduce the solvent consumption be further reduced overall.

Toners of any polymer base, e.g. on the basis of polystyrene, polyester and others used become. To each of these polymers exists in general a suitable solvent.

LIST OF REFERENCE NUMBERS

10

container

12

Solvent vapor

14

floor area

16

cooling pipes

18

upper area

20

middle area

22

support material

24

deflecting

26, 28

deflecting

30

air

P1

Transport direction of the carrier material

32

Zone with solvent depletion

34

directed stream

36

jet

38

Anströmstelle

40

fixing chamber

40a, 40b

Fixierkammern

42

entrance slit

44

exit slit

46

Evaporator

48

feed

50

plate

52

steam power

54

opening

56

Cross-flow fan

58

channel

60

explosion door

62

unloading

64, 66

suction

70, 72

control flaps

P2, P4

Verschwenkrichtungen

74, 74a, 74b

sensors

76a, 76b

solenoid valves

78

reservoir

80a, 80b

regulator

Claims (46)

1. An apparatus for fixing a toner image on a carrier material (22),
   in which the toner image is charged with a solvent vapour,
   a directed air stream (34) containing solvent vapor is generated,
   and in which the stream (34) is directed onto a section of the carrier material (22) with the assistance of a nozzle device (36),
   characterized in that solvent vapour is inside a fixing chamber (40) whose walls that come into contact with the solvent vapour are heated by heating means to a temperature that is at least equal to or higher than the temperature of ebullition of the solvent.
2. Apparatus according to claim 1, in which an acceleration device (56) is provided for generating the stream (34) containing the solvent vapour.
3. Apparatus according to claim 2, in which a cross current ventilator (56) is provided as an acceleration device.
4. Apparatus according to one of the preceding claims, in which a device for recovery and reuse of solvent vapour is provided, wherein the solvent vapour not absorbed by the carrier material (22) and the toner image is extracted, is enriched with a predetermined quantity of freshly evaporated solvent, and a stream (34) of solvent vapour that is supplied to the nozzle device (36) is generated anew.
5. Apparatus according to one of the preceding claims, in which the carrier material (22) is web-shaped and is preferably paper.
6. Apparatus according to one of the preceding claims, in which the carrier material (22) is transported in non-contacting fashion in the region in which it is charged with solvent vapour.
7. Apparatus according to one of the preceding claims, in which the carrier material (22) is electrostatically discharged with the assistance of a discharge device (62) before the charging with solvent vapour.
8. Apparatus according to one of the preceding claims, in which the stream (34) of solvent vapour is directed in moving direction (P1) of the carrier material (22).
9. Apparatus according to one of the preceding claims 1 to 7, in which the stream (34) of solvent vapour is directed opposite the moving direction (P1) of the carrier material (22).
10. Apparatus according to one of the preceding claims, in which the stream (34) of solvent vapour is guided along a channel section (58) having a defined length and within which the solvent vapour acts on the toner image and on the carrier material (22).
11. Apparatus according to one of the preceding claims, in which a gap nozzle (56) is provided as a nozzle device.
12. Apparatus according to one of the preceding claims, in which a heated plate (50) onto which liquid solvent is dripped is provided for the evaporation of the solvent.
13. Apparatus according to claim 12, in which the solvent is supplied by means of a delivery pipe (48), and in which the heated plate (50) is preferably chemically or mechanically roughened and/or is provided with channels.
14. Apparatus according to claim 12 or 13, in which the solvent is supplied to the heated plate (50) with the assistance of a nozzle that sprays the solvent.
15. Apparatus according to one of the preceding claims, in which at least one valve (82a, 82b), preferably a solenoid valve, that controls the flow of solvent from a reservoir (78) is provided.
16. Apparatus according to claim 15, in which the valve is driven such that a predetermined concentration of solvent is maintained in the stream of solvent vapour.
17. Apparatus according to claim 15 or 16, in which at least one sensor (74a, 74b) is provided that measures the solvent concentration in the stream (34) of solvent vapour, and in that the concentration of the solvent is regulated by control of the solenoid valve (82a, 82b).
18. Apparatus according to one of the preceding claims, in which a vapour stream valve (54) is provided that enables or stops the delivery of solvent vapour from an evaporator (46).
19. Apparatus according to one of the preceding claims, in which the fixing chamber (40) is secured by at least one explosion flap (60).
20. Apparatus according to one of the preceding claims, in which the carrier material (22) is guided in the fixing chamber (40) via an admission gap (42) and a discharge gap (44), and in that a respective extraction device (64, 66) at the admission gap (42) and at the discharge gap (44) extracts solvent vapour.
21. Apparatus according to one of the preceding claims, in which at least one control flap (70, 72) is provided with which the stream (34) of solvent vapour is deflected such in a deflection position that the carrier material (22) no longer has solvent vapour blown against it.
22. Apparatus according to claim 21, in which, for the immediate interruption of the fixing process, the control flap (70, 72) is driven into the deflection position, in that the flow of solvent for the evaporation process is stopped and/or one of the extraction devices (66) is turned off.
23. Apparatus according to one of the preceding claims 21 to 22, in which, given resumption of the transport of the carrier material, the control flap (70, 72) is swivelled from the deflection position into an enable position for the stream (34) of solvent vapour, the solvent flow for the evaporation process is started and/or in which the extraction device (66) is reactivated.
24. Apparatus according to one of the preceding claims, in which, given a stop of the forward transport of the carrier material (22), the fixing process is also stopped.
25. Apparatus according to one of the preceding claims, in which the carrier material (22) inside a fixing chamber is simultaneously respectively charged from both sides with a directed stream (34) of solvent vapour.
26. Apparatus according to one of the preceding claims 1 to 25, in which the evaporator (46) for generating the solvent vapour is arranged outside the fixing chamber (40).
27. Apparatus according to one of the preceding claims, in which the carrier material (22) - as viewed in transport direction (P1) - is successively charged by a first stream (34a) containing solvent vapour and then by a second stream (34b) containing solvent vapour.
28. Apparatus according to claim 27, in which the first stream (34a) and the second stream (34b) are identically directed.
29. Apparatus according to claim 27, in which the first stream (34a) and the second stream (34b) are directed opposite one another.
30. Apparatus according to one of the preceding claims 27 to 29, in which both streams (34a, 34b) are generated in a single chamber.
31. Apparatus according to one of the preceding claims 27 to 29, in which each stream (34a, 34b) is generated in a chamber (40a, 40b).
32. Apparatus according to one of the preceding claims 1 to 31, in which the solvent used for the solvent vapour has a low ozone potential.
33. Apparatus according to claim 32, in which the solvent is single-phase.
34. Apparatus according to claim 32 or 33, in which ester, preferably ethyl acetate, ketone, preferably acetone, or alcohol, preferably isopropanol, n-propanol, trans-1,2-dichloroethylene is employed as a solvent.
35. Apparatus according to one of the preceding claims, in which toner on the basis of polystyrol is employed.
36. Device for printing and/or copying, in which a band-shaped carrier material is printed with toner images on at least one side,
    the device being coupled to at least one apparatus according to one of the preceding claims.
37. Method for fixing a toner image on a carrier material (22),
    in which the toner image is charged with a solvent vapour,
    a directed air stream (34) containing solvent vapour is generated,
    and in which the stream (34) is directed onto a section of the carrier material (22) with the assistance of a nozzle device (36),
    characterized in that the solvent vapour is inside a fixing chamber (40) whose walls that come into contact with the solvent vapour are heated to a temperature that is at least equal to or higher than the temperature of ebullition of the solvent.
38. Method according to claim 37, in which an acceleration device (56), preferably a cross current ventilator (56), is provided for generating the stream (34) containing solvent vapour.
39. Method according to one of the preceding claims 37 or 38, in which the solvent vapour not absorbed by the carrier material (22) and the toner image is extracted, is enriched with a predetermined quantity of freshly evaporated solvent, and a stream (34) of solvent vapour that is supplied to the nozzle device (36) is generated anew.
40. Method according to one of the preceding claims 37 to 39, in which the stream (34) of solvent vapour is directed in moving direction (P1) of the carrier material (22).
41. Method according to one of the preceding claims 37 to 39, in which the stream (34) of solvent vapour is directed opposite the moving direction (P1) of the carrier material (22).
42. Method according to one of the preceding claims 37 to 41, in which the carrier material (22) inside a fixing chamber is simultaneously respectively charged from both sides with a directed stream (34) of solvent vapour.
43. Method according to one of the preceding claims 37 to 42, in which the solvent used for the solvent vapour has a low ozone potential.
44. Method according to claim 43, in which the solvent is single-phase.
45. Method according to claim 43 or 44, in which ester, preferably ethyl acetate, ketone, preferably acetone, or alcohol, preferably isopropanol, n-propanol, trans-1,2-dichloroethylene is employed as a solvent.
46. Method according to one of the preceding claims 37 to 45, in which toner on the basis of polystyrol is employed.

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