EP0082740B1 - Verfahren und Vorrichtung zum magnetographischen Kopieren - Google Patents

Verfahren und Vorrichtung zum magnetographischen Kopieren Download PDF

Info

Publication number
EP0082740B1
EP0082740B1 EP82400423A EP82400423A EP0082740B1 EP 0082740 B1 EP0082740 B1 EP 0082740B1 EP 82400423 A EP82400423 A EP 82400423A EP 82400423 A EP82400423 A EP 82400423A EP 0082740 B1 EP0082740 B1 EP 0082740B1
Authority
EP
European Patent Office
Prior art keywords
developer
magnetic
dots
image
carrier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82400423A
Other languages
English (en)
French (fr)
Other versions
EP0082740A3 (en
EP0082740A2 (de
Inventor
Jean Magnenet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bull SA
Original Assignee
Bull SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bull SA filed Critical Bull SA
Publication of EP0082740A2 publication Critical patent/EP0082740A2/de
Publication of EP0082740A3 publication Critical patent/EP0082740A3/fr
Application granted granted Critical
Publication of EP0082740B1 publication Critical patent/EP0082740B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G19/00—Processes using magnetic patterns; Apparatus therefor, i.e. magnetography

Definitions

  • the present invention relates to a magnetographic printing method which makes it possible to obtain images in two colors on a printing medium. It also relates to a machine for implementing this method.
  • Magnetic printing machines which, in response to signals received from a control unit, make it possible to form images, such as character images for example, on a printing medium generally consisting of a strip or a sheet of paper.
  • a printing medium generally consisting of a strip or a sheet of paper.
  • the printing of the images is carried out by first forming, from the signals received, a latent magnetic image on the surface of a magnetic recording element generally having the shape of a rotating drum or an endless belt, this latent image being made up of a set of magnetized zones of very small dimensions.
  • This latent image is then developed by depositing on this surface a powdery developer containing magnetic particles which remain applied only to the magnetized areas of the recording element to form a powder image on the surface of this element. After which, this powder image is transferred to the print medium.
  • the image which is thus formed on the printing medium may appear in two different colors.
  • the printing of a color image on the printing medium is carried out by first forming on the recording element an image latent magnetic corresponding to the parts of the same color of the image to be printed, by developing this latent image by means of a developer having this color, by transferring the powder image thus obtained onto the printing medium, and by repeating this operation as many times as there are colors in the image to be printed.
  • a method has the drawback of requiring a particularly long time for its implementation.
  • the particles which have a determined size (and consequently a given color) are preferentially attracted by the elementary areas whose dimensions correspond to a given force of attraction, so that, after development, each elementary area is covered with particles whose color corresponds to the frequency that was used to form this elementary area.
  • the present invention overcomes these drawbacks and proposes a magnetographic printing process, as well as a machine using this process, which makes it possible to obtain on a printing medium, in relatively short time, high-quality two-color images, while requiring only two developers to present both the same particle size and the same magnetic characteristics.
  • FIG. 7 represents the structure of the transfer station of the machine shown in FIG. 2.
  • FIG. 1A shows, in enlarged section, a magnetic recording element 10, of known type, which can be used for implementing the method of the invention.
  • this magnetic recording element is of a type analogous to that which has been described and represented in French patent NO 2,402,921 and that it comprises a support 11 formed of a material having a high magnetic permeability, such as iron or mild steel, this support being coated with a layer 12 of magnetic material with high coercivity, such as, for example, the nickel-cobalt magnetic alloy
  • this recording element 10 is magnetized transversely by means of one or more recording heads 13 of the type which has been represented in FIG. 3.
  • this recording head 13 comprises a magnetic core 14 on which is wound a winding E connected to an electrical excitation circuit which will be described later.
  • This magnetic core 14 has substantially the shape of a U and it is profiled so as to present at its ends a recording pole 15 and a flux closing pole 16. These two poles are arranged, as shown in FIG. 3 , near the surface of the magnetic layer 12, so that the magnetic core 14, the support 11 and the two regions 100 and 101 which are included between this core and this support and which are located respectively below the poles 15 and 16 form a magnetic circuit formed. It should be noted here that, although in the case illustrated in Figure 3, the poles 15 and 16 are located near the surface of the magnetic layer 12, we could adopt another arrangement in which these two poles would be placed in contact of this surface.
  • FIG. 3 also shows that the width d of the recording pole 15 is very small compared to that D of the flux closing pole 16. Under these conditions, if an electric current of intensity I is sent to the winding E , this current creates, inside the magnetic core 14, a magnetic flux whose line of average force is represented by the line in dashed lines 17. In the portion of the magnetic layer 12 which is located in the region 100 of the pole recording 15, the magnetic field is perpendicular to the surface of this layer 12, so that in this portion, the magnetization of the magnetic layer 12 is effected transversely.
  • the magnetic field created by the head 13 is greater than the saturation field of the magnetic layer 12 and therefore causes in this portion, the appearance of a practically point magnetized area usually called magnetized point, this magnetized area even remaining when the winding E then ceases to be traversed by a current.
  • the value the magnetic field created by the head 13 is much lower than that of the saturation field of the magnetic layer 12, so that this flux closure pole 16 can neither cause nor the formation of a magnetized zone in the layer 12, nor a modification of the magnetized zones already formed in this layer.
  • the magnetic layer 12 can be magnetized so that the magnetized zones thus formed constitute a latent magnetic image having a configuration determined for example the configuration of a character.
  • FIG. 5 shows a set of magnetized zones A arranged in a rectangular matrix comprising seven rows and five columns and distributed inside this matrix so as to constitute the image of the character "H ".
  • the spacing pitch P of the rows and columns of this matrix is at least equal to the transverse dimension L of a magnetized area.
  • the latent magnetic image which has been formed on the surface of the recording element is then developed by depositing on the surface of the magnetic layer 12 a powdery developer comprising finely divided particles, each formed from an organic thermoplastic resin in which a pigment and magnetic particles have been incorporated.
  • the surface of the magnetic layer 12 is subjected to a retouching operation which makes it possible to remove the developer particles which are in excess on this surface, so that, at the end of this operation, only the magnetized areas of this layer remains covered with a developer film, thus forming on the surface of layer 12 a powder image whose configuration corresponds to that of the magnetized zones.
  • This powder image is then transferred to a printing medium generally consisting of a strip of paper.
  • the present invention on the contrary, so that the image which is formed on the printing medium appears in one and / or the other of two previously chosen colors, the following method is used, the different phases of which will now be described with reference to Figures 1A to 1E.
  • the recording element 10 is magnetized so as to form on its surface magnetized zones which all have the same dimensions and which have magnetizations having all the same value.
  • FIG. 1A only two of these zones referenced A1 and A2 have been shown for reasons of simplification, but it is understood that the number of these magnetized zones can be absolutely arbitrary.
  • FIG. 1A the north (N) and south (S) magnetic polarities have also been shown, as well as the respective magnetizations J, and J 2 of the areas A1 and A2, each of these magnetizations being represented by an arrow whose length is proportional to the value of this magnetization. It is then seen, in FIG.
  • the magnetization of these zones is oriented in the opposite direction to the magnetizations of the zones intended to form, on this support, images or parts of images which must appear in the other color.
  • the areas A1 and A2 which have been shown in FIG. 1A and which have magnetizations of the same value, but in opposite directions, are intended to form on the printing paper two punctual spots of different colors.
  • the magnetized area A1 is intended to form a point spot of red color
  • the magnetized area A2 is intended to form a point spot of black color.
  • the recording element 10 having been magnetized in the manner which has just been indicated, a first powdery developer is then deposited on the surface of this element, the tint of which is one of the two colors chosen. In the example described, it will be considered that this first powdery developer is red in color.
  • the recording element 10 is then subjected to a retouching operation so that, at the end of this operation, the aforementioned magnetized areas A1 and A2 appear coated as shown in FIG. 1B with a thin layer 18 of the first powder developer.
  • a second powdery developer is then deposited on the surface of the recording element, the color of which is of the other of the two colors chosen, that is to say black in the example described.
  • the recording element 10 is subjected to a second retouching operation, so that, at the end of this operation, the magnetized zones A1 and A2 appear coated, as shown in FIG. 1C, with a second layer 19, very fine, of the second powdery developer, this second layer 19 thus being superimposed on the first layer 18.
  • a second layer 19 very fine, of the second powdery developer, this second layer 19 thus being superimposed on the first layer 18.
  • the force with which the different particles of the developers which remain on the magnetized zones of the recording element 10 are attracted depends not only on the value of the magnetizations of these zones, and on the distance which separates each particle of the area on which it is deposited, but also of the physical characteristics of these developers. This is why, it will be considered that the two developers which are used in the process of the invention have practically the same physical properties, in particular the same granulomeric state, the same coercive field, the same induction at saturation, the same intensity and the same melting point.
  • FIG. 6 also shows the values F 1 and F 2 of the retouching forces which are exerted on each of the developer particles during, respectively, the first retouching operation and the aforementioned second retouching operation, these forces being exerted against the magnetic force F m indicated above.
  • these two retouching forces F 1 and F 2 each have a constant value, the value of the force F 1 used during the first retouching operation being greater than that of the force F 2 used at the cost of the second retouching operation.
  • the value of the force F 1 is such that the straight line of ordinate F 1 intersects the curve 30 at a point I 1 , of abscissa e 1 .
  • the value of the force F 2 is such that the straight line of ordinate F 2 intersects the curve 30 at a point 1 2 , of abscissa e 2 greater than e 1 .
  • the value e 1 is the particular value of the distance h for which the retouching force F 1 is numerically equal to the magnetic force F M exerted by each magnetized zone on a developer particle located at the distance e 1 from this zone . It follows that, for the developer particles which, in the same zone, are at a distance from this zone greater than e 1 , the retouching force F 1 is greater than the magnetic force exerted by this zone on these particles, so that these particles will be removed from this area during the first retouching operation.
  • the layer 18 of the first developer has practically a thickness of 25 ⁇ m and that the thickness e 2 of this composite layer is substantially equal to 55 ⁇ m, so that the thickness of the layer 19 of the second developer is practically equal to 30 microns.
  • the values F 1 and F 2 of the retouching forces it is thus possible to arrange so that the layer 18 of first developer has a thickness e 1 of predetermined value and that the layer 19 of second developer has a thickness (e 2 ⁇ e 1 ) close to this value e 1 .
  • immediate proximity is meant that the distance which separates the strip of paper 20 of the surface of the recording element 10 is at most equal to one millimeter.
  • the magnetic field H which is produced by the device 21 is oriented perpendicular to the surface of the recording element 10 and its direction is opposite to that of the magnetization of the magnetized zones intended to form spots on the paper strip 20 punctual having the shade of the first powder developer.
  • the amplitude of the magnetic field H which causes a modification of the magnetic attraction forces exerted by each of the magnetized zones of the recording element is such that the abscissa e ' 1 , from point I' 1 above is less than 0.5e, while the abscissa e ' 2 of point 1' 2 above is less than 1.5e ,, but greater than e ,.
  • the amplitude of the magnetic field H which makes it possible to obtain the values of e ′ 1 and of e ′ 2 meeting these conditions can be determined, either mathematically or experimentally by varying the amplitude of this magnetic field and by measuring, for each of the different values of this field, the intensities of the corresponding magnetic forces exerted, at different distances h, by the magnetized zones whose magnetizations have been thus modified, then by plotting the two curves 31 and 32 which correspond to each amplitudes of the magnetic field H.
  • the amplitude of this magnetic field has a value such that the abscissa of the aforementioned point I ' 1 is substantially equal to 6 ⁇ m (therefore is less than the limit value of 12.5 ⁇ m), while that of point 1 ' 2 above is substantially equal to 33 ⁇ m (therefore is less than the limit value of 37.5 ⁇ m) but is greater than 25 ⁇ m.
  • this transfer will never be total.
  • this transfer operation has the effect of transferring onto the paper strip 20, as shown in FIG. 1E, the major part of the layer 19 of the second developer which has been deposited on each of the zones whose magnetizations have been reinforced, this part forming on the paper a small pile consisting of a layer 22 of the second developer, the thickness of this pile being, in the example described, close to 22 microns.
  • This transfer operation also has the effect of transferring onto the paper the whole of the second layer 19 and the major part of the layer 18 which have been deposited in superposition on each of the zones whose magnetizations have been reduced, so that this part is found on the paper by forming a pile 34 consisting of a layer 23 of the first developer which covers the entire layer 19 of the second developer, the thickness of this pile 34 being, in the example described, close to fifty microns .
  • the layers of developers 19, 22, 23 which have thus been transferred to the paper strip 20, are then subjected to a fixing operation, this operation being carried out at a temperature making it possible to bring the two developers to the viscous state, but not liquid, which prevents the two developers constituting the layers 19 and 23 from mixing.
  • the layer 19 is masked by the layer 23 which then forms on the paper a spot spot having the color of the first developer, that is to say red in the example described, while the layer 22 forms on this paper a spot spot having the shade of the second developer, that is to say black in the example described.
  • FIG. 2 there is shown a magnetographic printing machine which performs printing in two conliv according to the printing process which has just been described.
  • the machine which is shown in this figure comprises a magnetic recording element in the form of a magnetic drum 10 similar to that which has been described and shown in the aforementioned French patent No. 2,402,921, this drum being driven in rotation, in the direction indicated by arrow R, by an electric motor 25.
  • the magnetization of the magnetic layer of this drum is ensured by a set of n magnetic heads 13-1 to 13-n arranged one next to the other and aligned parallel to the axis of rotation of the drum, these heads being placed near the magnetic surface of this drum.
  • These heads which are of the type which has been represented in FIG. 3 are selectively excited by electrical pulses in seen by a pulse source 26 and applied to the windings of these heads via a current reversing device 27, the structure of which has been shown in detail in FIG. 4.
  • each of the respective windings E-1 to En of magnetic heads 13-1 to 13-n is connected to two terminals (+) and (-) of a DC source , by means of four contacts, these contacts being designated, in FIG. 4 by KN, KI, LN and LI followed by the index of the winding E which they control.
  • the winding E-1 corresponds to the group of four contacts KN-1, KI-1, KN-1, LI-1.
  • winding E-2 corresponds to the group of four contacts KN-2, KI-2, LN-2, LI-2, and so on.
  • the contacts KN and LN of the same group are controlled simultaneously by a relay coil BN, while the contacts KI and LI of this group are controlled simultaneously by a relay coil BI, these coils BN and BI being assigned the same index than the contacts they order. All these coils BN-1 to BN-n and BI-1 to BI-n can be excited by electrical pulses supplied on the outputs S1 to Sn of the pulse source 26.
  • each of the coils BN-1 to BN-n is connected to a respective one of n changeover contacts 1-1 to In, each of these contacts being itself connected to a respective one of the outputs S1 to Sn via a respective one of n conductors W1 to Wn.
  • Figure 4 shows that each of these contacts 1-1 to In has two positions which, in the figure, have been designated by 1 and 2, each of the coils BN-1 to BN-n not being effectively connected to one respective of the outputs S1 to Sn only when the change-over contact with which it is associated is in position 1.
  • each of the coils BI-1 to BI-n is connected to one of the outputs S1 to Sn of the source 26 , via a respective one of the reversing contacts 1-1 to In, the connection between each of these coils and a respective one of said outputs being effectively ensured only when the reversing contact with which this coil is associated is in position 2.
  • the latent magnetic image necessary for printing a character is obtained by selectively exciting seven different times, five contiguous heads taken from among all of the heads magnetic 13-1 to 13-n, this excitation being carried out by means of pulses delivered at successive instants t i , t 2 , t 3 , t 4 , t s , t 6 and t 7 , on five corresponding outputs S1 at Sn of the pulse source 26.
  • the pulse source 26 delivers, at time t 1, a pulse on each of its outputs S2 to S4 at time t 2 a pulse on each of its outputs S1 to S5, at time t 3 a pulse on its output S5, at time t 4 a pulse on each of its outputs S1, S2, S3, and S5, at time t 5 a pulse on each of its outputs S1 to S5, at time t 6 a pulse on each of its outputs S1 to S5, and finally at time t 7 a pulse on each of its outputs S2 to S4.
  • the reversing contacts 1-1 to In are intended to determine the direction in which the magnetization of the magnetized zones on the drum 10 will be oriented, this its conditioning the color of the spot spot which will subsequently be formed on the paper by each of these magnetized zones .
  • each of the reversing contacts 1-1 to I-n is associated with a respective one of the magnetic heads 13-1 to 13-n.
  • the pulse which, sent by the source 26, arrives at this changeover contact is directed towards the coil BN which is associated with it.
  • this pulse is directed towards the coil BI which is associated with this change-over contact.
  • this pulse arrives at the coil BI-1.
  • the coil BI-1 which is thus excited momentarily by this pulse, then closes its contacts KI-1 and LI-1 for a short time, so that a direct current flows momentarily in the winding E-1 of the head 13-1, in the direction indicated by the arrow I. Therefore, this magnetic head 13-1 forms on the surface of the drum 10 a practically punctual magnetized zone, this zone having a magnetization J which remains after the disappearance of this current.
  • Positioning of the changeover contacts 1-1 to In, in either of positions 1 and 2 can be carried out, either manually by the operator before any printing operation , either fully automatically, the changeover contacts 1-1 to In being, in the latter case, controlled by actuation means of known type excited by the same control unit as that which controls the operation of the pulse source 26. It should also be noted that, depending on the case and application, some of the change-over contacts 1- 1 a In can be placed in position 2, while the other change-over contacts are placed in position 1, which allows, when printing a line of characters for example, to obtain characters printed in one of the two colors, while the other characters are printed in the other color.
  • the current reversing device 27 which has been shown in FIG. 2 is constituted, in the example described, by the assembly comprising the reversing contacts 1-1 to In, the coils BN-1 to BN- n and BI-1 to BI-n and the contacts KN-1 to KN-n, KI-1 to KI-n, LN-1 to LN-n and LI-1 to LI-n, all these elements being connected between aux as shown in Figure 4.
  • the printing machine produced according to the invention also comprises a first applicator device 40, of known type, which makes it possible to apply to the surface of the drum 10, particles of a first powdery developer contained in a reservoir 49.
  • this first developer is red in color.
  • This first applicator device 40 is established for depositing on each of the magnetized zones of the drum 10, a layer of first developer, the thickness of which is at least equal to 60 ⁇ m.
  • this applicator device 40 is of the type which have been described and represented in French patents No.
  • this device comprising on the one hand a rotating magnetic element which brings the developer particles from the tank 49 to the vicinity of the surface of the drum 10, on the other hand a deflector interposed between this element and the drum to form a trough in which the particles collected by the deflector accumulate, this deflector leaving between it and the drum a very small opening of the order of 1 millimeter through which pass the particles which have come to be applied against the surface of this drum.
  • the magnetized areas of the drum 10 which have thus been coated with a layer of first developer then pass in front of a retouching device 41 which makes it possible, on the one hand, to remove the developer particles remaining on the drum 10 outside the magnetized areas , on the other hand to remove the excess developer on these magnetized areas so that the thickness of the developer layer on each of these areas becomes practically equal to the value defined above.
  • the retouching device 41 which is used for this operation can be of the magnetic, electrostatic or pneumatic type. It will be considered that, in the example described, this retouching device 41 is of the type which has been described and shown in French patent No.
  • the thickness of the layer of the first developer is practically equal to 25 ⁇ m
  • the total thickness of the two layers is therefore at least equal to 85 ⁇ m. It will be considered that, in the example described, this total thickness is of the order of a hundred ⁇ m.
  • This second retouching device 43 makes it possible, on the one hand, to remove the particles of second developer which remain on the drum 10 outside the magnetized zones, on the other hand to reduce the thickness of the second developer layer which is superimposed on the layer of the first developer so that preferably the thickness e 2 and e, of this second layer practically equal to the value e, defined above.
  • the second retouching device 43 is set so that this second layer has a thickness practically equal to 30 ⁇ m. Under these conditions, the total thickness of the assembly constituted by the two layers thus superimposed is substantially equal to 55 ⁇ m.
  • the machine which has been shown in FIG. 2 comprises a transfer station which, in the example described, comprises two rollers 44 and 45 over which the paper strip 20 passes.
  • the roller 45 is a pressure roller which allows the strip of paper 20 to be applied to the drum 10 with a determined value force. It has been found that, in order to carry out a correct transfer of the developers onto the paper strip 20, this force should not exceed 600 newtons per linear meter.
  • this force has been adjusted, by known means (not shown) such as springs, so as to be substantially equal to 200 newtons per linear meter.
  • the roller 44 which is arranged upstream of the roller 45 with respect to the direction of travel of the drum and the paper strip, is on the contrary, a guide roller which, as can be seen in FIG. 7, makes it possible to bring the strip of paper 20 in the immediate vicinity of the surface of the drum 10, a little before this strip is applied against this surface.
  • FIG. 7 indeed shows that the point T where the strip 20 comes into contact with the drum 10 is located between the rollers 44 and 45.
  • the machine shown in FIG. 2 also includes a magnetic field generating device 21 which is arranged at the level of the transfer station, that is to say between the rollers 44 and 45.
  • this device 21 is constituted by a permanent magnet, but it should be noted however that this magnet could be replaced by any other device equivalent, for example by a magnetic induction coil excited by a direct current.
  • the direction and the H value of the magnetic field produced by this device 21 are chosen in the manner which has been explained in detail above, so that, during the transfer, the strip of paper receives, on the one hand, most of the layer of the second developer which has been deposited on the magnetized zones intended to form on the spot punctual spots having the color of this second developer, on the other hand the entire layer of the second developer and most of the layer of the first developer which have been deposited superimposed on the magnetized zones intended to form on the paper spot spots having the color of the first developer.
  • the magnetic field generating device 21 is preferably arranged between the guide roller 44 and the aforementioned point T, but close to this point T. It has in fact been found that this arrangement makes it possible to improve the efficiency of the transfer and the quality of the image formed on the paper during this transfer.
  • the machine which has been shown in FIG. 2 also includes a developer fixing device 46 under which the paper strip 20 passes when the transfer operation which has just been described has been carried out.
  • This fixing device 46 which is constituted, in the example described, by an electrically heated element, is intended to permanently fix the developers which have been transferred to the paper strip 20. It should be noted here that this fixing device 46 is adjusted so that these developers undergo practically no fusion, but only a sufficient softening to ensure their fixing on the paper. Under these conditions, no mixing of colors is likely to occur in the heaps of developers which, such as 34, comprise layers of developers of different shades. Thus each pile such as 34 forms, when it then cools on the paper, a point spot having the shade of the first developer, while each pile such as 22 forms, by cooling on this paper, a point spot having the shade from the second developer.
  • the machine shown in Figure 2 further comprises a cleaning device which, consisting of a brush 47 in the example described, ensures the cleaning of the parts of the surface of the drum which have passed in front of the transfer station. After this cleaning, these parts pass in front of an erasing device 48, of the electromagnetic type, which erases the latent magnetic images carried by these parts, so that these parts are again able to be magnetized when they become then present in front of the set of magnetic heads 13-1 to 13-n.
  • a cleaning device consisting of a brush 47 in the example described, ensures the cleaning of the parts of the surface of the drum which have passed in front of the transfer station. After this cleaning, these parts pass in front of an erasing device 48, of the electromagnetic type, which erases the latent magnetic images carried by these parts, so that these parts are again able to be magnetized when they become then present in front of the set of magnetic heads 13-1 to 13-n.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)

Claims (8)

1. Magnetographisches Druckverfahren, welches darin besteht, daß die Oberfläche eines magnetischen Aufzeichnungselementes in einer Richtung senkrecht zu dieser Oberfläche derart magnetisiert wird, daß eine Menge von magnetisierten Punkten gebildet wird, die ein latentes magnetisches Bild ergeben, anschließend auf dieser Oberfläche ein pulverförmiger Entwickler aufgebracht wird, der nur an den magnetisierten Punkten der genannten Oberfläche anhaftet, um so ein Pulverbild zu erzeugen, und schließlich dieses Pulverbild auf einen Druckträger zu übertragen, wobei dieses Verfahren dadurch gekennzeichnet ist, daß es, um auf diesem Träger ein Bild in zwei zuvor gewählten Farben aufzudrucken, darin besteht, daß:
-zunächst die Oberfläche des Aufzeichnungselementes magnetisiert wird, um magnetisierte Punkte zu bilden, welche dieselbe Magnetisierungsintersität, jedoch entgegengesetzte Polung aufweisen, wobei die magnetische Polung der Punkte zur Erzeugung von Bildteilen, die auf dem Träger in einer der genannten Farben erscheinen sollen, entgegengesetzt zu derjenigen der Punkte ist, die für die Erzeugung der anderen Teile dieses Bildes bestimmt sind;
- anschließend auf dieser Oberfläche ein erster pulverförmiger Entwickler aufgebracht wird, dessen Färbung diejenige einer ersten der genannten Farben ist;
- auf dieser Oberfläche ein zweiter pulverförmiger Entwickler aufgebracht wird, dessen Färbung die der zweiten Farbe ist und der jedoch dieselben physikalischen Eigenschaften wie der erste Entwickler aufweist, wobei diese zwei Entwickler auf diese Weise übereinander an den magnetisierten Punkten der genannten Oberfläche haften;
- und eine Teilübertragung des auf der Oberfläche des Aufzeichnungselementes erzeugten Pulverbildes auf den Träger vorgenommen wird, wobei diese Übertragung in Anwesenheit eines konstanten Magnetfeldes durchgeführt wird, das senkrecht zu dieser Oberfläche orientiert ist, wobei die Stärke und der Sinn dieses Magnetfeldes derart gewählt sind, daß die Magnetisierungsstärke der Punkte zur Erzeugung derjenigen Bildteile auf dem Träger, deren Farbe die des ersten pulverförmigen Entwicklers ist, vermindert wird und die Magnetisierungsstärke der anderen magnetisierten Punkte verstärkt wird, um auf den Träger nur den zweiten Entwickler derjenigen Punkte, deren Magnetisierungsstärke vergrößert wurde, sowie die beiden Entwickler zu übertragen, die an denjenigen Punkten einander überlagert sind, deren Magnetisierungsstärke vermindert wurde.
2. Druckverfahren nach Anspruch 1, dadurch gekennzeichnet, daß eine Retuschierung nach jedem Vorgang des Aufbringens von Entwickler auf der Oberfläche des Aufzeichnungselementes vorgenommen wird, wobei die magnetische Anziehungskraft, die von jedem magnetisierten Punkt auf ein Teilchen des auf diesem Punkt aufgebrachten Entwicklers ausgeübt wird, in Abhängigkeit von der Entfernung zwischen diesem Teilchen und diesem Punkt variiert, und daß der Wert (F2) der bei der zweiten Retuschierung angewendeten Kraft kleiner als der Wert (Fi) der bei der ersten Retuschierung angewendeten Kraft und derart gewählt ist, daß die Dicke der Schicht des zweiten Entwicklers im wesentlichen gleich der der Schicht des ersten Entwicklers ist.
3. Druckverfahren nach Anspruch 2, dadurch gekennzeichnet, daß, wenn e'i die Entfernung darstellt, für welche die genannte magnetische Kraft, wenn sie durch das konstante Magnetfeld geschwächt wird, gleich der Übertragungskraft ist, und e'2 die Entfernung darstellt, für welche diese magnetische Kraft, wenn sie durch das konstante Magnetfeld verstärkt wird, gleich dieser Übertragungskraft ist, die Stärke des konstanten Magnetfeldes derart ist, daß der Wert der genannten Entfernung e'2 kleiner als 1,5 e1 ist, während der Wert der genannten Entfernung e', kleiner als 0,5 e, ist, worin e, die Dicke der Schicht des ersten Entwicklers ist, die nach der ersten Retuschierung entsteht.
4. Magnetographischer Drucker zur Durchführung des Verfahrens nach Anspruch 1, mit einem Aufzeichnungselement (10), das mit einer magnetischen Aufzeichnungsoberfläche versehen ist, einer Mehrzahl von Magnetköpfen 13-1 bis 13-n, die durch elektrische Impulse angesteuert werden und derart ausgebildet sind, daß sie ansprechend auf diese Impulse die genannte Aufzeichnungsoberfläche in einer zu dieser Oberfläche senkrechten Richtung magnetisieren, um auf ihr eine Menge von magnetisierten Punkten (A) zu erzeugen, welche ein latentes magnetisches Bild darstellen, Antriebsmitteln (25) zur Verursachung einer Relativbewegung zwischen dem Aufzeichnungselement und den Magnetköpfen, einer Impulsquelle (26), die derart ausgebildet ist, daß sie elektrische Impulse selektiv an die genannten Köpfe anlegt, einer Aufbringvorrichtung (40) zum Aufbringen eines pulverförmigen Entwicklers auf der genannten Aufzeichnungsoberfläche, wobei dieser Entwickler nur an den magnetisierten Punkten dieser Oberfläche anhaftet, um ein Pulverbild zu erzeugen, und mit einer Übertragungsstation (44, 45) zur Übertragung des genannten Pulverbildes auf einen Druckträger, wobei die Maschine dadurch gekennzeichnet ist, daß der genannte Entwickler Teilchen enthält, deren Färbung einer von zwei zuvor gewählten Farben entspricht, und daß sie ferner enthält:
- Stromumkehrmittel (27), welche zwischen den Magnetköpfen (13-1 bis 13-n) und der Impulsquelle (26) angeordnet sind, um den Stromsinn der von der Quelle ausgegebenen Impulse selektiv zu invertieren und so auf der Aufzeichnungsoberfläche ein latentes magnetisches Bild zu erzeugen, dessen magnetisierte Punkte dieselbe Magnetisierungsstärke (J1, J2) aufweisen, die jedoch entgegengesetzte Polung besitzen, wobei die magnetische Polung der Punkte zur Erzeugung von Pulverbildteilen in einer der genannten Farben entgegengesetzt zur Polung der Punkte ist, die zur Erzeugung der anderen Teile dieses Bildes bestimmt sind,
- eine zweite Aufbringvorrichtung (42), die zwischen der Übertragungsstation (44,45) und der ersten Aufbringvorrichtung (40) angeordnet ist, um einen zweiten pulverförmigen Entwickler auf der genannten Aufzeichnungsoberfläche aufzubringen, wobei dieser zweite Entwickler Teilchen enthält, deren Färbung die der anderen der genannten Farbe ist, welcher jedoch dieselben physikalischen Eigenschaften wie der erste Entwickler aufweist, wobei der zweite Entwickler nur an den magnetisierten Punkten der genannten Oberfläche anhaftet und dabei über dem ersten pulverförmigen Entwickler liegt,
- und eine Vorrichtung (21) zur Erzeugung eines Magnetfeldes, welche an der Übertragungsstation angeordnet ist, um ein konstantes Magnetfold auf die genannte Aufzeichnungsoberfläche senkrecht zu dieser einwirken zu lassen, wobei die Stärke (H) und die Richtung dieses Magnetfeldes derart gewählt sind, daß die Magnetisierungsintersität der magnetisierten Punkte zur Erzeugung derjenigen Pulverbildteile auf dem Träger, deren Farbe die des ersten pulverförmigen Entwicklers ist, vermindert wird und die Magnetisierungsstärke der anderen magnetisierten Punkte vergrößert wird, so daß nur der zweite Entwickler, der auf Punkten aufgebracht wurde, deren Magnetisierung verstärkt wurde, auf den Druckträger übertragen wird, während beide Entwickler, die auf Punkten aufgebracht wurden, deren Magnetisierung vermindert wurde, übereinanderliegend auf diesen Träger überführt werden.
5. Druckmaschine nach Anspruch 4, dadurch gekennzeichnet, daß sie ferner eine erste Retuschiervorrichtung (41), weiche zwischen den zwei Aufbringvorrichtungen (40 und 42) angeordnet und derart eingestellt ist, daß sie auf jedem magnetisierten Punkt der Aufzeichnungsoberfläche nur eine Schicht des ersten Entwicklers verbleiben läßt, deren Dicke im wesentlichen gleich einem vorbestimmten Werk e, ist, und eine zweite Retuschiervorrichtung (43) enthält, welche zwischen der zweiten Aufbringvorrichtung (42) und der Übertragungsstation (44, 45) angeordnet und derart eingestellt ist, daß sie auf jeder der Schichten des ersten Entwicklers nur eine Schicht des zweiten Entwicklers verbleiben läßt, deren Dicke im wesentlichen gleich dem genannten Wert e, ist.
6. Druckmaschine nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß das Aufzeichnungselement durch eine Magnettrommel (10) gebildet ist, die Übertragungsstation (44, 45) einerseits eine Druckrolle (45) zum Anlegen des Druckträgers (20) gegen diese Trommel und andererseits eine Führungsrolle (44) enthält, die bewegungsaufwärts von der Druckrolle angeordnet ist, damit der Träger mit dieser Trommel an einem zwischen diesen zwei Rollen liegenden Punkt (T) in Berührung kommen kann, und daß die Vorrichtung (21) zur Erzeugung des Magnetfeldes im wesentlichen auf der Höhe dieses Punktes angeordnet ist.
7. Druckmaschine nach einem der Ansprüche 4 bis 6, dadurch gekennzeichnet, daß die Vorrichtung (21) zur Magnetfelderzeugung als Permanentmagnet ausgebildet ist.
8. Druckmaschine nach einem der Ansprüche 4 bis 7, dadurch gekennzeichnet, daß sie ferner eine Fixiervorrichtung (46) enthält, die längs der Bewegungsbahn des Druckträgers bewegungsabwärts von der Übertragungsstation (44, 45) angeordnet ist, wobei diese Fixiervorrichtung derart eingestellt ist, daß die auf diesem Träger aufgebrachten und vor der Fixiervorrichtung vorbeibewegten Entwicklerteilchen aufgeweicht, jedoch nicht geschmolzen werden.
EP82400423A 1981-12-23 1982-03-09 Verfahren und Vorrichtung zum magnetographischen Kopieren Expired EP0082740B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8124056 1981-12-23
FR8124056A FR2518771A1 (fr) 1981-12-23 1981-12-23 Procede et machine d'impression magnetographique

Publications (3)

Publication Number Publication Date
EP0082740A2 EP0082740A2 (de) 1983-06-29
EP0082740A3 EP0082740A3 (en) 1983-08-10
EP0082740B1 true EP0082740B1 (de) 1985-05-29

Family

ID=9265311

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82400423A Expired EP0082740B1 (de) 1981-12-23 1982-03-09 Verfahren und Vorrichtung zum magnetographischen Kopieren

Country Status (5)

Country Link
US (1) US4449130A (de)
EP (1) EP0082740B1 (de)
JP (1) JPS58111075A (de)
DE (1) DE3263850D1 (de)
FR (1) FR2518771A1 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2568697B1 (fr) * 1984-08-01 1987-03-20 Bull Sa Procede et machine d'impression magnetographique
US5764429A (en) * 1996-04-29 1998-06-09 Eastman Kodak Company Magnetic writing of repetitive information on magnetic wheel and magnization head for media
EP1783564B1 (de) * 2005-10-17 2014-12-03 Sagemcom Documents Sas Druckvorrichtung mit Magnetisierungverfahren und vorrichtung zur Bilderzeugung

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3824601A (en) * 1972-03-28 1974-07-16 Bell & Howell Co Multi-color magnetic image recording and media
US4126494A (en) * 1975-10-20 1978-11-21 Kokusai Denshin Denwa Kabushiki Kaisha Magnetic transfer record film

Also Published As

Publication number Publication date
FR2518771A1 (fr) 1983-06-24
US4449130A (en) 1984-05-15
EP0082740A3 (en) 1983-08-10
JPS58111075A (ja) 1983-07-01
FR2518771B1 (de) 1984-03-30
DE3263850D1 (en) 1985-07-04
EP0082740A2 (de) 1983-06-29

Similar Documents

Publication Publication Date Title
FR2564609A1 (fr) Procede et appareil de developpement
EP0082740B1 (de) Verfahren und Vorrichtung zum magnetographischen Kopieren
EP0082742B1 (de) Verfahren und Vorrichtung zum magnetographischen Kopieren
EP0082739B1 (de) Verfahren und Vorrichtung zum magnetographischen Kopieren
EP0082741B1 (de) Verfahren und Vorrichtung zum magnetographischen Kopieren
EP0172767B1 (de) Verfahren und Gerät zum magnetographischen Kopieren
EP0328428B1 (de) Vorrichtung zum periodischen Auftragen von Teilchen eines pulverförmigen Entwicklers auf den Aufnahmeträger eines magnetographischen Druckers
EP0315509B1 (de) Verfahren zum Fixieren eines auf einem Blatt gelegenen Pulverentwicklers und Vorrichtung zum Fixieren dieses Entwicklers nach diesem Verfahren
EP0631209B1 (de) Druckverfahren mit mindestens einem Bild und einer Presse zur Durchführung dieses Verfahrens
EP0099763B1 (de) Einrichtung zum Anbringen von Entwicklungspulver auf der Aufzeichnungsrolle eines nichtmechanischen Druckers
CA1261912A (fr) Procede et machine d'impression magnetographique
EP1040926B1 (de) Magnetisches Druckverfahren
FR2600178A1 (fr) Element d'enregistrement magnetique destine a etre utilise dans une imprimante magnetographique
EP0193691A1 (de) Anschlaglose Druckmaschine
LU81413A1 (fr) Procede et appareil d'impression electrostatique
FR2581772A1 (fr) Procede d'electrocopie
EP0336820B1 (de) Vorrichtung zur Bildung latenter magnetischer Bilder auf einem Aufzeichnungsträger in einem Drucker
FR2522864A1 (fr) Dispositif de compensation thermique de la deformation thermique d'une piece destinee a etre en contact avec une autre piece
FR2490847A1 (fr) Element d'enregistrement magnetique
EP0056470B1 (de) Vorrichtung zur Herstellung einer drehbaren Magnetbürste
FR2637992A1 (fr) Tete d'enregistrement electrostatique, dispositif d'enregistrement d'images et dispositif d'affichage comportant une telle tete, dispositif d'alimentation d'un agent de developpement utilise dans une telle tete et procede pour fabriquer cette derniere
FR2522839A1 (fr) Procede et dispositif d'impression magnetographique
FR2625574A1 (fr) Dispositif pour eliminer la pollution due aux charges electriques acquises par un support d'impression dans une machine imprimante magnetographique
FR2522857A1 (fr) Dispositif d'ecriture et/ou de lecture d'informations sur un support magnetique, a frottements reduits contre ce support
EP0291392A1 (de) Pulverförmige Substanz zur Reibungsverminderung des Aufnahmeträgers eines magnetischen Druckers

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Designated state(s): BE DE GB IT NL

AK Designated contracting states

Designated state(s): BE DE GB IT NL

17P Request for examination filed

Effective date: 19830720

ITF It: translation for a ep patent filed

Owner name: FUMERO BREVETTI S.N.C.

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): BE DE GB IT NL

REF Corresponds to:

Ref document number: 3263850

Country of ref document: DE

Date of ref document: 19850704

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19980211

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19980331

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19990305

Year of fee payment: 18

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990331

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19990517

Year of fee payment: 18

BERE Be: lapsed

Owner name: CIE INTERNATIONALE POUR L'INFORMATIQUE CII - HONEY

Effective date: 19990331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19991001

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 19991001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000309

REG Reference to a national code

Ref country code: GB

Ref legal event code: 732E

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20000309

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010103