Production of latent images by curie point recording

Claim 1

An apparatus for providing a latent image on a uniformly magnetized carrier, comprising: means including a radiation field modulated by a line pattern, further including a magnetizing field below room temperature coercivity of the carrier, for providing to the carrier a line pattern of magnetic poles, defined by pole lines of alternating opposite polarities, having predominant directions of extension which are parallel to each other, there being local variations of the line spacing, the spacing variable between a substantial equidistant spacing of neighboring lines and at least an approximate merger of pairs of neighboring lines, through a range of asymmetrical spacing between any line and its two neighboring lines; and means for providing for such variation in the line spacing in dependence upon a two-dimensional contrasting information field, wherein field areas of maximum darkness of the latent image to be produced causing the line spacing to be equidistant, field areas of maximum brightness of the latent image to be produced causing at least approximate merger of a pair of neighboring lines.

Claim 2

An apparatus for providing a latent image on a uniformly magnetized carrier, comprising: means including a radiation field modulated by a line pattern, further including a magnetizing field below room temperature coercivity of the carrier, for providing to the carrier a line pattern of magnetic poles, defined by pole lines of alternating opposite polarities, having predominant directions of extension which are parallel to each other, there being local variations of the line spacing, the spacing variable between a substantial equidistant spacing of neighboring lines and at least an approximate merger of pairs of neighboring lines, through a range of asymmetrical spacing between any line and its two neighboring lines; and means for providing for such variation in the line spacing in dependence upon a two-dimensional contrasting information field, wherein field areas of maximum darkness of the latent image to be produced causing the line spacing to be equidistant, field areas of maximum brightness of the latent image to be produced causing at least approximate merger of a pair of neighboring lines.

Claim 5

An apparatus for providing a latent magnetic image on a low Curie point storage carrier, the Curie point separating temperature dependent ferromagnetic and paramagnetic states of the carrier, the carrier being uniformly longitudinally magnetized, comprising: means for thermally biasing said carrier in a line pattern, where along substantially parallel lines the carrier receives a particular amount of thermal energy and neighboring regions of the carrier receive an amount of energy depending upon the distance of the neighboring region from the closest one of said lines; means for providing information energy to the carrier, the information energy being locally variable over the surface of the carrier in dependence upon a two-dimensional, contrasting information field, the energy being locally gradually variable between first and second values representing extreme contrasts of the information, the information energy being added as thermal energy to the biasing energy, so that first regions of variable width symmetrically disposed respectively in relation to said lines are in a first one of said magnetic states, and second regions in between said first regions are in the second one of said magnetic states, said first and second regions having substantially equal width in regions of said carrier receiving said first value of information energy, said first regions having a width substantially different from the interspaced second regions, in regions of said carrier receiving approximately said second value of information energy, the regions being in the paramagnetic state, reverting to the ferromagnetic state after decay of the informative energy; and means for magnetizing all of said regions in the paramagnetic state while reverting to the ferromagnetic state with below-room temperature coercivity field, subsequently to the providing of the information energy, the magnetization being different from the initial uniform magnetization of the carrier.

Claim 6

An apparatus for providing a latent magnetic image on a low Curie point storage carrier, the Curie point separating temperature dependent ferromagnetic and paramagnetic states of the carrier, the carrier being uniformly longitudinally magnetized, comprising: means for thermally biasing said carrier in a line pattern, where along substantially parallel lines the carrier receives a particular amount of thermal energy and neighboring regions of the carrier receive an amount of energy depending upon the distance of the neighboring region from the closest one of said lines; means for providing information energy to the carrier, the information energy being locally variable over the surface of the carrier in dependence upon a two-dimensional, contrasting information field, the energy being locally gradually variable between first and second values representing extreme contrasts of the information, the information energy being added as thermal energy to the biasing energy, so that first regions of variable width symmetrically disposed respectively in relation to said lines are in a first one of said magnetic states, and second regions in between said first regions are in the second one of said magnetic states, said first and second regions having substantially equal width in regions of said carrier receiving said first value of information energy, said first regions having a width substantially different from the interspaced second regions, in regions of said carrier receiving approximately said second value of information energy, the regions being in the paramagnetic state, reverting to the ferromagnetic state after decay of the informative energy; and means for magnetizing all of said regions in the paramagnetic state while reverting to the ferromagnetic state with below-room temperature coercivity field, subsequently to the providing of the information energy, the magnetization being different from the initial uniform magnetization of the carrier.

Claim 7

An apparatus for providing a latent magnetic image on a low Curie point storage carrier, the Curie point separating temperature dependent ferromagnetic and paramagnetic states of the carrier, the carrier being uniformly longitudinally magnetized; means for providing to the carrier a first field of radiant energy being intensity modulated in accordance with a two-dimensional information field, the intensity modulation ranging between first and second values, the difference representing maximum contrast; means for providing to said carrier a second field of radiant energy modulated in accordance with a line pattern in which the radiation energy has a particular intensity along equidistantly spaced particular lines, and in which the intensities along lines parallel to the particular lines differ from the particular intensity by an amount related to the distance from the closest particular line and over a particular range of distance values, areas of said carrier receiving information energy having said first value causing regions of said carrier along said particular lines and for a width about half the line spacing of the particular lines to have a first one of said magnetic states, the in-between regions to have the second one of said magnetic states, the width of said regions varying in accordance with information energy values in between said first and second values; and means for magnetizing the carrier where in the paramagnetic state with below-room temperature coercivity field so that magnetic poles are set up, after the regions in the paramagnetic state revert to the ferromagnetic state, the poles appearing along the border of the regions which were in the paramagnetic state.

Claim 8

An apparatus for providing a latent magnetic image on a low Curie point storage carrier, the Curie point separating temperature dependent ferromagnetic and paramagnetic states of the carrier, the carrier being uniformly longitudinally magnetized; means for providing to the carrier a first field of radiant energy being intensity modulated in accordance with a two-dimensional information field, the intensity modulation ranging between first and second values, the difference representing maximum contrast; means for providing to said carrier a second field of radiant energy modulated in accordance with a line pattern in which the radiation energy has a particular intensity along equidistantly spaced particular lines, and in which the intensities along lines parallel to the particular lines differ from the particular intensity by an amount related to the distance from the closest particular line and over a particular range of distance values, areas of said carrier receiving information energy having said first value causing regions of said carrier along said particular lines and for a width about half the line spacing of the particular lines to have a first one of said magnetic states, the in-between regions to have the second one of said magnetic states, the width of said regions varying in accordance with information energy values in between said first and second values; and means for magnetizing the carrier where in the paramagnetic state with below-room temperature coercivity field so that magnetic poles are set up, after the regions in the paramagnetic state revert to the ferromagnetic state, the poles appearing along the border of the regions which were in the paramagnetic state.

Claim 15

The method of selectively providing a positive or negative image of a picture comprising the steps of: magnetizing a carrier to establish a substantially uniform magnetization; providing radiation to said magnetized carrier, the radiation being modulated in accordance with the contrasts of said picture maximum contrast being established by the difference between a maximum and minimum radiation level; providing a selected thermal biasing Pattern, concurrently with said last step, concurrence established with reference to any particular spot of the carrier as affected by radiation in accordance with the biasing pattern; selecting prior to said last step the operating levels for the thermal biasing pattern among a first one for producing an alternating heating pattern varying in one direction on the carrier surface between narrow, regularly spaced radiation minima and from which radiation intensities increase about linearly to a level exceeding the Curie level of the carrier covering a strip, in between adjacent minima for a width about half the value of the spacing between the adjacent minima, and a second one for producing a line heating pattern of regularly equidistantly spaced narrow maxima at about Curie level with slopes from the maximum of approximately linearly declining temperatures in the vicinity of each maximum; applying, concurrently with said two steps for providing, a magnetic field to said carrier for magnetizing regions where the Curie level was exceeded, the magnetic field to persist beyond the duration of the two providing steps for any area on the carrier, the magnetic field being insufficient to destroy the magnetization in the carrier in accordance with the first step and in portions of the carrier remaining below the Curie point, thereof; and developing the image resulting from the previous steps by applying magnetizable particles to said carrier.

Claim 16

The method of selectively providing a positive or negative image of a picture comprising the steps of: magnetizing a carrier to establish a substantially uniform magnetization; providing radiation to said magnetized carrier, the radiation being modulated in accordance with the contrasts of said picture maximum contrast being established by the difference between a maximum and minimum radiation level; providing a selected thermal biasing Pattern, concurrently with said last step, concurrence established with reference to any particular spot of the carrier as affected by radiation in accordance with the biasing pattern; selecting prior to said last step the operating levels for the thermal biasing pattern among a first one for producing an alternating heating pattern varying in one direction on the carrier surface between narrow, regularly spaced radiation minima and from which radiation intensities increase about linearly to a level exceeding the Curie level of the carrier covering a strip, in between adjacent minima for a width about half the value of the spacing between the adjacent minima, and a second one for producing a line heating pattern of regularly equidistantly spaced narrow maxima at about Curie level with slopes from the maximum of approximately linearly declining temperatures in the vicinity of each maximum; applying, concurrently with said two steps for providing, a magnetic field to said carrier for magnetizing regions where the Curie level was exceeded, the magnetic field to persist beyond the duration of the two providing steps for any area on the carrier, the magnetic field being insufficient to destroy the magnetization in the carrier in accordance with the first step and in portions of the carrier remaining below the Curie point, thereof; and developing the image resulting from the previous steps by applying magnetizable particles to said carrier.

Claim 20

An apparatus for providing a latent magnetic image on a uniformly longitudinally magnetized carrier having a Curie point separating ferromagnetic and paramagnetic states, comprising: means for providing radiation to the magnetized carrier, the radiation having intensities to selectively provide strips of substantially equal width of spacially alternating paramagnetic and ferromagnetic states, dissimilarly wide strips of alternating paramagnetic and ferromagnetic states, and a substantially uniform region of one of said states; means for controlling the radiation providing means in accordance with a two-dimensional information pattern for the selection of the radiation intensity reaching any particular point on the carrier; and means for magnetizing the paramagnetic portions of the carrier uniformly, longitudinally but oppositely to the magnetization as provided by the first means, the magnetization to persist while the paramagnetic portions revert to the ferromagnetic state.

Claim 21

An apparatus for providing a latent magnetic image on a uniformly longitudinally magnetized carrier having a Curie point separating ferromagnetic and paramagnetic states, comprising: means for providing radiation to the magnetized carrier, the radiation having intensities to selectively provide strips of substantially equal width of spacially alternating paramagnetic and ferromagnetic states, dissimilarly wide strips of alternating paramagnetic and ferromagnetic states, and a substantially uniform region of one of said states; means for controlling the radiation providing means in accordance with a two-dimensional information pattern for the selection of the radiation intensity reaching any particular point on the carrier; and means for magnetizing the paramagnetic portions of the carrier uniformly, longitudinally but oppositely to the magnetization as provided by the first means, the magnetization to persist while the paramagnetic portions revert to the ferromagnetic state.

Claim 22

The method of providing a negative image of a picture, comprising the steps of: magnetizing a flat carrier to establish a substantially uniform magnetization, the carrier having Curie point separating ferromagnetic and paramagnetic states: providing radiation to said magnetized carrier, the radiation being modulated with the contrasts of said picture, and including local areas of minimum radiation intensity corresponding to incremental picture areas to be printed at minimum toner density, and other areas of maximum radiation intensity corresponding to incremental picture areas be printed at maximum toner density; providing, concurrently with the preceding step, a two-dimensionally modulated radiation bias to said magnetized carRier, the modulation being a line pattern, but areas of the carrier receiving said minimum radiation intensity retaining the initial magnetization essentially independent from the line pattern, the local minimum radiation failing to heat the carrier above the Curie point, areas in the carrier receiving said maximum radiation being heated in a pattern defined by equidistantly spaced strips that are being heated above the Curie point separated by strips of similar width wherein the ferromagnetic state and initial magnetization is retained, areas receiving half tone representing radiation intensities of the picture representing radiation, being heated in a line pattern, wherein the line width of heating above the Curie point is smaller than the width of the lines in between; providing to the carrier a below room temperature coercivity magnetizing field of orientation different from the original magnetization, to persist upon decay of said radiation and during reversion of heated increments of the carrier to the ferromagnetic state; and applying magnetizable toner particles to the carrier, for maximum adherence density to areas where there was established the equidistant line spacing, defining after reversion to the ferromagnetic state an area of equidistantly spaced magnetic pole lines, alternating in polarity in direction transverse to the direction of line extension of the radiation bias.

Claim 23

The method of providing a negative image of a picture, comprising the steps of: magnetizing a flat carrier to establish a substantially uniform magnetization, the carrier having Curie point separating ferromagnetic and paramagnetic states: providing radiation to said magnetized carrier, the radiation being modulated with the contrasts of said picture, and including local areas of minimum radiation intensity corresponding to incremental picture areas to be printed at minimum toner density, and other areas of maximum radiation intensity corresponding to incremental picture areas be printed at maximum toner density; providing, concurrently with the preceding step, a two-dimensionally modulated radiation bias to said magnetized carRier, the modulation being a line pattern, but areas of the carrier receiving said minimum radiation intensity retaining the initial magnetization essentially independent from the line pattern, the local minimum radiation failing to heat the carrier above the Curie point, areas in the carrier receiving said maximum radiation being heated in a pattern defined by equidistantly spaced strips that are being heated above the Curie point separated by strips of similar width wherein the ferromagnetic state and initial magnetization is retained, areas receiving half tone representing radiation intensities of the picture representing radiation, being heated in a line pattern, wherein the line width of heating above the Curie point is smaller than the width of the lines in between; providing to the carrier a below room temperature coercivity magnetizing field of orientation different from the original magnetization, to persist upon decay of said radiation and during reversion of heated increments of the carrier to the ferromagnetic state; and applying magnetizable toner particles to the carrier, for maximum adherence density to areas where there was established the equidistant line spacing, defining after reversion to the ferromagnetic state an area of equidistantly spaced magnetic pole lines, alternating in polarity in direction transverse to the direction of line extension of the radiation bias.

Claim 24

The method of providing a positive image of a picture, comprising the steps of: magnetizing a flat carrier to establish a substantially uniform magnetization, the carrier having Curie point separating ferromagnetic and paramagnetic states; providing radiation to said magnetized carrier, the radiation being modulated with the contrasts of said picture, and including local areas of minimum radiation intensity corresponding to incremental picture areas to be printed at maximum toner density, and other areas of maximum radiation intensity corresponding to incremental picture areas be printed at minimum toner density; providing, concurrently with the preceding step, a two-dimensionally modulated radiation bias to said magnetized carrier, the modulation being a line pattern, but areas of the carrier receiving said maximum radiation intensity being demagnetized essentially independent from the line pattern by local radiation heating of the carrier above the Curie point, areas in the carrier receiving said minimum radiation being heated in a pattern defined by equidistantly spaced strips that are being heated above the Curie point separated by strips of similar width wherein the ferromagnetic state and initial magnetization is retained, areas receiving half tone representing radiation intensities of the picture representing radiation, being heated in a line pattern, wherein the line width of heating above the Curie point is larger than the width of the lines in between; providing to the carrier a below room temperature coercivity magnetizing field of orientation different from the original magnetization, to persist upon decay of said radiation and during reversion of heated increments of the carrier to the ferromagnetic state; and applying magnetizable toner particles to the carrier, for maximum adherence density to areas where there was established the equidistant line spacing, defining after reversion to the ferromagnetic state an area of equidistantly spaced magnetic pole lines, alternating in polarity in direction transverse to the direction of line extension of the radiation bias.

Claim 25

The method of providing a positive image of a picture, comprising the steps of: magnetizing a flat carrier to establish a substantially uniform magnetization, the carrier having Curie point separating ferromagnetic and paramagnetic states; providing radiation to said magnetized carrier, the radiation being modulated with the contrasts of said picture, and including local areas of minimum radiation intensity corresponding to incremental picture areas to be printed at maximum toner density, and other areas of maximum radiation intensity corresponding to incremental picture areas be printed at minimum toner density; providing, concurrently with the preceding step, a two-dimensionally modulated radiation bias to said magnetized carrier, the modulation being a line pattern, but areas of the carrier receiving said maximum radiation intensity being demagnetized essentially independent from the line pattern by local radiation heating of the carrier above the Curie point, areas in the carrier receiving said minimum radiation being heated in a pattern defined by equidistantly spaced strips that are being heated above the Curie point separated by strips of similar width wherein the ferromagnetic state and initial magnetization is retained, areas receiving half tone representing radiation intensities of the picture representing radiation, being heated in a line pattern, wherein the line width of heating above the Curie point is larger than the width of the lines in between; providing to the carrier a below room temperature coercivity magnetizing field of orientation different from the original magnetization, to persist upon decay of said radiation and during reversion of heated increments of the carrier to the ferromagnetic state; and applying magnetizable toner particles to the carrier, for maximum adherence density to areas where there was established the equidistant line spacing, defining after reversion to the ferromagnetic state an area of equidistantly spaced magnetic pole lines, alternating in polarity in direction transverse to the direction of line extension of the radiation bias.