CA1205778A - Image reproduction by in plane electro-coagulation of a colloid - Google Patents
Image reproduction by in plane electro-coagulation of a colloidInfo
- Publication number
- CA1205778A CA1205778A CA000454450A CA454450A CA1205778A CA 1205778 A CA1205778 A CA 1205778A CA 000454450 A CA000454450 A CA 000454450A CA 454450 A CA454450 A CA 454450A CA 1205778 A CA1205778 A CA 1205778A
- Authority
- CA
- Canada
- Prior art keywords
- negative
- colloid
- positive electrode
- matrix
- positive
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
- B41C1/00—Forme preparation
- B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
- B41C1/105—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by electrocoagulation, by electro-adhesion or by electro-releasing of material, e.g. a liquid from a gel
Abstract
ABSTRACT
A method and system for high speed image repro-duction by electro-coagulation of an electrolytically coagulable colloid. A plurality of negative and positive electrolytically inert electrodes which are electrically insulated from one another are arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each matrix element having respective planar active sur-faces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity thereto. A layer of substantially liquid colloidal dispersion is applied over the negative positive electrode active surfaces of the matrix elements whereby the negative and positive electrode active surfaces are disposed on the same side of the layer of colloidal dispersion, the colloidal dispersion containing an electroly-tically coagulable colloid, a liquid dispersing medium and a soluble electrolyte, and having a substantially uniform temperature throughout the layer. An electrical field is generated between the negative and positive electrodes of selected ones of the matrix elements, the electrical field extending substantially parallel to the planar active surfaces of the negative and positive electrodes, whereby to cause selective coagulation and adherence of the colloid onto the positive electrode active surfaces of the selected matrix elements, thereby forming a series of corresponding dots representative of a desired image, and any remaining non-coagulated colloid is thereafter removed.
A method and system for high speed image repro-duction by electro-coagulation of an electrolytically coagulable colloid. A plurality of negative and positive electrolytically inert electrodes which are electrically insulated from one another are arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each matrix element having respective planar active sur-faces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity thereto. A layer of substantially liquid colloidal dispersion is applied over the negative positive electrode active surfaces of the matrix elements whereby the negative and positive electrode active surfaces are disposed on the same side of the layer of colloidal dispersion, the colloidal dispersion containing an electroly-tically coagulable colloid, a liquid dispersing medium and a soluble electrolyte, and having a substantially uniform temperature throughout the layer. An electrical field is generated between the negative and positive electrodes of selected ones of the matrix elements, the electrical field extending substantially parallel to the planar active surfaces of the negative and positive electrodes, whereby to cause selective coagulation and adherence of the colloid onto the positive electrode active surfaces of the selected matrix elements, thereby forming a series of corresponding dots representative of a desired image, and any remaining non-coagulated colloid is thereafter removed.
Description
~5~7~
B~CKGROUND OF T~IE INVENTION
The present invention relates to improvements in high speed image reproduction. More particularly, the invention is concerned wi-th an improved method and .system for reproducing an image by the electro-coagulation of an electrolytically coagulable colloid.
Applicant has already described in his U.S.
Patent ~o. 3,892,645 of July 1, 1975 an electric printing method and system in which a thin layer of a liquid composition contalning a colloid such as gelatin or albumin, water and an electrolyte is interposed between at least one pair of opposite negative and positive electrodes spaced from one another to define a gap which is filled by the liquid cornposition. In one embodiment, there is a plurality of electrically-insulated juxtaposed negative electrodes and selected ones thereof are elec-trically energized to pass electric pulses throu~h the layer at selected points to cause point by point selective coagulation and adherence of the colloid on the positive electrode directly opposite each energized negative electrode, thereby forming imprints.
It is very important that the gap between the negative and positive electrodes be uniform throughout the active surfaces of the electrodes since otherwise there will be a variation in the thickness of the layer and thus a corresponding variation of the electrical resistance thereof at different locations between the electrodes, which will result in a non-uniform image reproduction as the thic]~ness of the coagulated colloid ls proportional to the amount of current passed through ,3~ r 7~3 the layer. Since this gap is of the order of 50 ~, its uniformity is of course very difficult to controlO More-over, where the negative electrode~ are energized more than once in the reproduction of an image, these become polarized resulting in a gas generation and accumulation at the negative electrodes, which adversely affect the image reproduction.
SUMMARY OF THE INVENTION
_ It is therefore an object of the present inven-tion to overcome the aforementioned drawbacks and toprovide a method and system for reproducing an image by the electro-coagulation of a colloid, which do not necessitate a critical control of the electrode gap nor cause electrode polarization which may hinder the image reproduction.
According to one aspect of the i.nvention, there is provided a method of reproducing an image by electro-coagulation of an electrolytically coagulable colloid, which comprises the steps of:
a~ providing a plurality of negative and positive electrolytically inert electrodes electrically insulated from one another and arranged to define a matrix of dot-fonming elements, the negative and positive electrodes of each matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity thereto, b) applying a layer of a substantially liquid colloidal dispersion over the negative and positive electrode active surfaces of the matrix elements whereby the negative and positive elec-trode active surfaces are disposed on the same side of the layer of colloidal dispersion, the colloidal ~L2~5771~
dispersion containing an electrolytically coagu]able colloid, a liquid dispersing medium and a soluble electxolyte and hav-ing a substantially uniform temperature throughout the layer c) generating an electrical field between the negative and positive electrodes of selected ones oE the matrix elements, the electrical field extenaing substantially parallel to the planar active surfaces of the negative and positive electrodes, whereby to cause selective coagulation.
and adherence of the colloid onto the positive electrode active surfaces of the selected matrix elernents, thereby forming a series of corresponding dots representative of a desired image, and d) removing any remaining non-coagulated colloid.
The invention also provides, in a further aspect thereof, a system for reproducing an image by electro-coagulation of an electrolytically coagulable colloid, which comprises:
- a plurality of negative and positive electroly-tically inert electrodes electrically insulated from one another and arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity there-to, the electrode active surfaces being adapted to receive thereover a layer of a substantially li~uid colloidal dis-persion containing an electrolytically coagulable colloid, a liquid dispersing medium and a soluble electrolyte and having a substantially uniform temperature throughout the layer, and - means for electrically energi.zing the negative and positive electrodes of selected ones of the matrix elements to cause selective coagulation and adherence of the colloid . - 3 -7~
onto the pos.itive electrode active surfaces of the selected matrix elements and to -thereby form a series of corresponding dots representative of a desired image.
Thus, according to the invention, since the active surfaces of the negative and positive electrodes are no longer disposed opposite one another in differen-t planes, but rather extend in substantially the same plane, there is no longer any necessity of having to control in precise manner the thickness of the layer of colloidal dispersion applied. Also, since the electrodes of each dot-forming rnatrix element are eneryized only once in the reproduction of an i.mage, there are barely any electrode polarization and resulting gas accumulation that may hinder -the image reproduction.
In a preferred embodiment of the invention, the negative and positive electrodes of the matrix comprise respectively first and second sets of mutually electrically-insulated band-like electrode members disposed in parallel side-by-side relation, the negative electrode members of the first set extending transversely of the positive electrode members of -the second set and being formed with a plurality of protruding conductive elements which are spaced along the length thereof and each have a planar active end surface. The protruding elements of each negative electrode member extend through corresponding bores formed in the positive electrode members to te.rminate flush therewith such that the planar active end surface of each protruding element and a planar active surface portion of each positive electrode member adjacent each bore extend in a substantially common plane whe-reby to define the aforesaid matrix elements. Thus, the electrical energizing of the negative and positive elec-trodes of selected ~atr:ix elements may be effected by se~uentially energizing the electrode members of one set and concurrently ' ,~
~577~3 energizing selected ones of the electrode members of the other set. Preferably, the positi~e electrode - 4a ~
,.. .
77~
members are sequentially energized while selected ones of the negative electrode members are concurrently energized.
rrhe concurrent selective energizing of the electrode members of the other set is advantageously effected by sweeping such electrode members and trans-mitting electrical pulses to selected ones thereof during sweeping. These elec-trical pulses can be varied either in voltage or time from one electrode member to another so as to correspondingly vary the amount of coagulated co~loid adhered onto the positive electrode active surfaces of the selected matrix elements. This enables one to form dots of varying intensities and thus to reproduce the half-tones of an image.
The colloid generally used is a linear colloid of high molecular weight, that is, one having a molecular weight comprised between about 10,000 and about 1,000,000, preferably ~etween 100,000 and 500,000. Examples of suitable colloids include animal proteins such as albumin, gelatin and casein, vegetable proteins such as agar and synthetic copolymers such as polyacrylic acid, polyacrylamide, polyvinyl alcohol and derivatives thereof. ~ater is preferably used as the medium for dispersing the colloid to provide the desired colloidal dispersion.
The colloidal dispersion also contains a soluble electrolyte which enables the water to have a greater conductivity; the water is believed to migrate under direct current towards the negative electrode and thereby cause the colloidal dispersion to dry out, result-3U ing in coagulation of the colloid and adherence thereo~
onto the positive electrode. Examples of suitable ~: _ 0 _ ., electrolytes include chlorides and sulfates, such as potassium chloride, sodium chloride, calcium chloride, nickel chloride, lithium chloride, ammonium chloride, and manganese sulfate. Since the speed of electro coagulation is affected by ternperature, the layer of colloidal dis-persion must be maintained at a substantially constant temperature, for instance by using a thermostatic water jacket, in order to ensure a uniform image reproduction.
After coagulation of the colloid, any remaining non-coagulated colloid is removed by any suitable means, such as by washlng off, airjet or wiping to fully uncover the coagulated colloid.
The applications of the invention are basically the same as those mentioned in Applicant's U.S~ Patent 15 ~o. 3,892,645. For example, the coagulated colloid can ~e colored with a water-soluble dve which is absorbed thereby and the colored coagulated colloid may then be transferred onto an end-use support, such as paper.
The coagulated colloid can also be set or hardened chemically or by irradiation so as to be used for off-set lithographic printing. Moreover, it is possible to produce several differently colored images of coagulated colloid which can be transferred onto an end-use support in superimposed relation to provide a polychromatic ima~e.
~RIEF DESCRIPTION OF THE DRAWI~GS
Further features and advantages of the inven-tion will become more readily apparent from the following description of preferred embodiments thereof as illus-trated by way of e~amples in the accompanying drawings, ~r~
;~7~
in which:
Figure 1 schematically illustrates an image reproduction system according to the inven-tion, the dot rnatrix printer of which is shown partially cut away, Figure 2 is fragmentary exploded view of the dot matrix printer shown in Fig. 1, Figure 3 is a sectional view taken along line 3-3 of Fig. l;
Figure ~ is another sectional view taken along line 4-4 of Fig. 1, Figure 5 is a top view of a matrix element of the dot matrix printer shown in Fig. 1, and Figure 6 is a view similar to Fig. 5 but show-ing a different type of matrix element.
The image repro~uction system illustrated in Fig. 1 includes a dot matrix printer which is generally designated by reference numeral 10 and comprises two superimposed sets of electrically-insulated negative and positive band-like electrode members 12 and 14 disposed in parallel side-by-side relation, the negative electrode members 12 extending transversely of the positive electrode members 14 to define at their intersections a plurality of dot-forming matrix elements 16. Each negative electrode member 12 is electrically connected to a sweepirlg device 18 which is connected to the negative terminal of a direct current power supply ~0 via a modulator 22 coupled to an electronic counter 24 operative to transmit electrical pulses to selected ones of the electrode members 1~ during the sweeping thereof by the device 180 The modulator serves to vary ~!
7~
the electrical pulses either in voltage or time.
Each positive electrode member 14, on the other hand, is electrically connected to another sweeping device 1~' which is connected to the positive terminal of the power supply 20. Thus, the electrodes of selected ones of the matrix elements 16 are electrically energi~ed by sequentially energizing the positive electrode members 14 with the sweeping device 18' and concurrently sweeping the negative electrode members 12 with the device 1~ while transmitting with the counter 24 electrical pulses to selected electrode members 12, which are modulated either in voltage or time by the modulator 22.
As shown in Figs 2-4 t the negative and positive electrode members are electricall~ insulated from one an-other by means of a layer of insulating material 26 having a thickness of about 10 ~. The negative electrode mem-bers 12 are also electrically insulated from one another by a layer of insulating material 28 having a thickness of about 25 ~. The positive electrode members 14 are similarly insulated by means of a layer of insulating material 30 having a thickness of about 10 to 25 ~, preferably 10 ~. Each negative electrode member 12 is formed with a plurality of protruding conductive elements 32 of circular cross-section which are spaced along the length thereof and each have a planar active end surface 34. The protruding elements 32 of each negative electrode 12 extend through corresponding bores 36 formed in the positive electrode members 14 to terminate flush there-with such that the planar active end surface 34 of eachelement 32 and a planar active surface portion 3~3 of a positive electrode member 14 adjacent a bore 36 extend in a comrnon plane. Each protruding element 32 is of course electrically insulated from its adjacent positive elec-trode member 14 by means of a layer of insulating material 40 swch as silicon mono~ide, having a thickness of about 5 to 10 ~, preferably 10 ~.
Thus, the planar end surface 34 of each protrud-iny element 32 and the planar surface portion 38 of each positive electrode member 14 adjacent each element 32 constitute the electrode active surfaces of each dot-forming matrix element 16. Each matrix element prefer-ably has a square surface area of abou-t 125 ~ x 125 ~, the protruding element 32 of each matrix element 16 being disposed cen-trally thereof and having a diameter of about 25 to 50 ~, the elements 32 are therefore invisible to the naked eye. The dot matrix printer 10 comprises about 40,000 of such ma-trix elements 16 per square inch.
The negative electrode members 12 can be made of any metal, copper or stainless steel being preferred.
However, the positive electrode members 14 must be made of a metal that will resist electrolytic attack and enhance electro-coagulation, such as stainless steel, aluminum, nickel, chromium or tin, these metals being
B~CKGROUND OF T~IE INVENTION
The present invention relates to improvements in high speed image reproduction. More particularly, the invention is concerned wi-th an improved method and .system for reproducing an image by the electro-coagulation of an electrolytically coagulable colloid.
Applicant has already described in his U.S.
Patent ~o. 3,892,645 of July 1, 1975 an electric printing method and system in which a thin layer of a liquid composition contalning a colloid such as gelatin or albumin, water and an electrolyte is interposed between at least one pair of opposite negative and positive electrodes spaced from one another to define a gap which is filled by the liquid cornposition. In one embodiment, there is a plurality of electrically-insulated juxtaposed negative electrodes and selected ones thereof are elec-trically energized to pass electric pulses throu~h the layer at selected points to cause point by point selective coagulation and adherence of the colloid on the positive electrode directly opposite each energized negative electrode, thereby forming imprints.
It is very important that the gap between the negative and positive electrodes be uniform throughout the active surfaces of the electrodes since otherwise there will be a variation in the thickness of the layer and thus a corresponding variation of the electrical resistance thereof at different locations between the electrodes, which will result in a non-uniform image reproduction as the thic]~ness of the coagulated colloid ls proportional to the amount of current passed through ,3~ r 7~3 the layer. Since this gap is of the order of 50 ~, its uniformity is of course very difficult to controlO More-over, where the negative electrode~ are energized more than once in the reproduction of an image, these become polarized resulting in a gas generation and accumulation at the negative electrodes, which adversely affect the image reproduction.
SUMMARY OF THE INVENTION
_ It is therefore an object of the present inven-tion to overcome the aforementioned drawbacks and toprovide a method and system for reproducing an image by the electro-coagulation of a colloid, which do not necessitate a critical control of the electrode gap nor cause electrode polarization which may hinder the image reproduction.
According to one aspect of the i.nvention, there is provided a method of reproducing an image by electro-coagulation of an electrolytically coagulable colloid, which comprises the steps of:
a~ providing a plurality of negative and positive electrolytically inert electrodes electrically insulated from one another and arranged to define a matrix of dot-fonming elements, the negative and positive electrodes of each matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity thereto, b) applying a layer of a substantially liquid colloidal dispersion over the negative and positive electrode active surfaces of the matrix elements whereby the negative and positive elec-trode active surfaces are disposed on the same side of the layer of colloidal dispersion, the colloidal ~L2~5771~
dispersion containing an electrolytically coagu]able colloid, a liquid dispersing medium and a soluble electxolyte and hav-ing a substantially uniform temperature throughout the layer c) generating an electrical field between the negative and positive electrodes of selected ones oE the matrix elements, the electrical field extenaing substantially parallel to the planar active surfaces of the negative and positive electrodes, whereby to cause selective coagulation.
and adherence of the colloid onto the positive electrode active surfaces of the selected matrix elernents, thereby forming a series of corresponding dots representative of a desired image, and d) removing any remaining non-coagulated colloid.
The invention also provides, in a further aspect thereof, a system for reproducing an image by electro-coagulation of an electrolytically coagulable colloid, which comprises:
- a plurality of negative and positive electroly-tically inert electrodes electrically insulated from one another and arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity there-to, the electrode active surfaces being adapted to receive thereover a layer of a substantially li~uid colloidal dis-persion containing an electrolytically coagulable colloid, a liquid dispersing medium and a soluble electrolyte and having a substantially uniform temperature throughout the layer, and - means for electrically energi.zing the negative and positive electrodes of selected ones of the matrix elements to cause selective coagulation and adherence of the colloid . - 3 -7~
onto the pos.itive electrode active surfaces of the selected matrix elements and to -thereby form a series of corresponding dots representative of a desired image.
Thus, according to the invention, since the active surfaces of the negative and positive electrodes are no longer disposed opposite one another in differen-t planes, but rather extend in substantially the same plane, there is no longer any necessity of having to control in precise manner the thickness of the layer of colloidal dispersion applied. Also, since the electrodes of each dot-forming rnatrix element are eneryized only once in the reproduction of an i.mage, there are barely any electrode polarization and resulting gas accumulation that may hinder -the image reproduction.
In a preferred embodiment of the invention, the negative and positive electrodes of the matrix comprise respectively first and second sets of mutually electrically-insulated band-like electrode members disposed in parallel side-by-side relation, the negative electrode members of the first set extending transversely of the positive electrode members of -the second set and being formed with a plurality of protruding conductive elements which are spaced along the length thereof and each have a planar active end surface. The protruding elements of each negative electrode member extend through corresponding bores formed in the positive electrode members to te.rminate flush therewith such that the planar active end surface of each protruding element and a planar active surface portion of each positive electrode member adjacent each bore extend in a substantially common plane whe-reby to define the aforesaid matrix elements. Thus, the electrical energizing of the negative and positive elec-trodes of selected ~atr:ix elements may be effected by se~uentially energizing the electrode members of one set and concurrently ' ,~
~577~3 energizing selected ones of the electrode members of the other set. Preferably, the positi~e electrode - 4a ~
,.. .
77~
members are sequentially energized while selected ones of the negative electrode members are concurrently energized.
rrhe concurrent selective energizing of the electrode members of the other set is advantageously effected by sweeping such electrode members and trans-mitting electrical pulses to selected ones thereof during sweeping. These elec-trical pulses can be varied either in voltage or time from one electrode member to another so as to correspondingly vary the amount of coagulated co~loid adhered onto the positive electrode active surfaces of the selected matrix elements. This enables one to form dots of varying intensities and thus to reproduce the half-tones of an image.
The colloid generally used is a linear colloid of high molecular weight, that is, one having a molecular weight comprised between about 10,000 and about 1,000,000, preferably ~etween 100,000 and 500,000. Examples of suitable colloids include animal proteins such as albumin, gelatin and casein, vegetable proteins such as agar and synthetic copolymers such as polyacrylic acid, polyacrylamide, polyvinyl alcohol and derivatives thereof. ~ater is preferably used as the medium for dispersing the colloid to provide the desired colloidal dispersion.
The colloidal dispersion also contains a soluble electrolyte which enables the water to have a greater conductivity; the water is believed to migrate under direct current towards the negative electrode and thereby cause the colloidal dispersion to dry out, result-3U ing in coagulation of the colloid and adherence thereo~
onto the positive electrode. Examples of suitable ~: _ 0 _ ., electrolytes include chlorides and sulfates, such as potassium chloride, sodium chloride, calcium chloride, nickel chloride, lithium chloride, ammonium chloride, and manganese sulfate. Since the speed of electro coagulation is affected by ternperature, the layer of colloidal dis-persion must be maintained at a substantially constant temperature, for instance by using a thermostatic water jacket, in order to ensure a uniform image reproduction.
After coagulation of the colloid, any remaining non-coagulated colloid is removed by any suitable means, such as by washlng off, airjet or wiping to fully uncover the coagulated colloid.
The applications of the invention are basically the same as those mentioned in Applicant's U.S~ Patent 15 ~o. 3,892,645. For example, the coagulated colloid can ~e colored with a water-soluble dve which is absorbed thereby and the colored coagulated colloid may then be transferred onto an end-use support, such as paper.
The coagulated colloid can also be set or hardened chemically or by irradiation so as to be used for off-set lithographic printing. Moreover, it is possible to produce several differently colored images of coagulated colloid which can be transferred onto an end-use support in superimposed relation to provide a polychromatic ima~e.
~RIEF DESCRIPTION OF THE DRAWI~GS
Further features and advantages of the inven-tion will become more readily apparent from the following description of preferred embodiments thereof as illus-trated by way of e~amples in the accompanying drawings, ~r~
;~7~
in which:
Figure 1 schematically illustrates an image reproduction system according to the inven-tion, the dot rnatrix printer of which is shown partially cut away, Figure 2 is fragmentary exploded view of the dot matrix printer shown in Fig. 1, Figure 3 is a sectional view taken along line 3-3 of Fig. l;
Figure ~ is another sectional view taken along line 4-4 of Fig. 1, Figure 5 is a top view of a matrix element of the dot matrix printer shown in Fig. 1, and Figure 6 is a view similar to Fig. 5 but show-ing a different type of matrix element.
The image repro~uction system illustrated in Fig. 1 includes a dot matrix printer which is generally designated by reference numeral 10 and comprises two superimposed sets of electrically-insulated negative and positive band-like electrode members 12 and 14 disposed in parallel side-by-side relation, the negative electrode members 12 extending transversely of the positive electrode members 14 to define at their intersections a plurality of dot-forming matrix elements 16. Each negative electrode member 12 is electrically connected to a sweepirlg device 18 which is connected to the negative terminal of a direct current power supply ~0 via a modulator 22 coupled to an electronic counter 24 operative to transmit electrical pulses to selected ones of the electrode members 1~ during the sweeping thereof by the device 180 The modulator serves to vary ~!
7~
the electrical pulses either in voltage or time.
Each positive electrode member 14, on the other hand, is electrically connected to another sweeping device 1~' which is connected to the positive terminal of the power supply 20. Thus, the electrodes of selected ones of the matrix elements 16 are electrically energi~ed by sequentially energizing the positive electrode members 14 with the sweeping device 18' and concurrently sweeping the negative electrode members 12 with the device 1~ while transmitting with the counter 24 electrical pulses to selected electrode members 12, which are modulated either in voltage or time by the modulator 22.
As shown in Figs 2-4 t the negative and positive electrode members are electricall~ insulated from one an-other by means of a layer of insulating material 26 having a thickness of about 10 ~. The negative electrode mem-bers 12 are also electrically insulated from one another by a layer of insulating material 28 having a thickness of about 25 ~. The positive electrode members 14 are similarly insulated by means of a layer of insulating material 30 having a thickness of about 10 to 25 ~, preferably 10 ~. Each negative electrode member 12 is formed with a plurality of protruding conductive elements 32 of circular cross-section which are spaced along the length thereof and each have a planar active end surface 34. The protruding elements 32 of each negative electrode 12 extend through corresponding bores 36 formed in the positive electrode members 14 to terminate flush there-with such that the planar active end surface 34 of eachelement 32 and a planar active surface portion 3~3 of a positive electrode member 14 adjacent a bore 36 extend in a comrnon plane. Each protruding element 32 is of course electrically insulated from its adjacent positive elec-trode member 14 by means of a layer of insulating material 40 swch as silicon mono~ide, having a thickness of about 5 to 10 ~, preferably 10 ~.
Thus, the planar end surface 34 of each protrud-iny element 32 and the planar surface portion 38 of each positive electrode member 14 adjacent each element 32 constitute the electrode active surfaces of each dot-forming matrix element 16. Each matrix element prefer-ably has a square surface area of abou-t 125 ~ x 125 ~, the protruding element 32 of each matrix element 16 being disposed cen-trally thereof and having a diameter of about 25 to 50 ~, the elements 32 are therefore invisible to the naked eye. The dot matrix printer 10 comprises about 40,000 of such ma-trix elements 16 per square inch.
The negative electrode members 12 can be made of any metal, copper or stainless steel being preferred.
However, the positive electrode members 14 must be made of a metal that will resist electrolytic attack and enhance electro-coagulation, such as stainless steel, aluminum, nickel, chromium or tin, these metals being
2~ electro-negative with respect to hydrogen. The surfaces 3 of the positive electrode members 14 are advantageously unpolished to enhance the adherence of the coagulated colloid thereon. The electrode members 14 can be produced by ion sputtering and can thus be as thin as 10 ,u~
In order to reproduce an image with the system ~ust described, a layer of a liquid colloidal Q~7~
dispersion containing a colloid such as ge:Latin or albumin, water and an electrolyte such as potassium chloride, and having a suhstantially uniform temperature throughout -the layer, is applied over the surface of the dot matrix printer 10. The sweeping devices 18 and 18' and the counter 24 are then activated so as to elec-trically energize the electrodes of selected ones of the matrix elements 16 and thereby cause selective coagula-tion and adherence of the colloid onto the positive electrode active surfaces 38 of the selected matrix elements, the coagulated colloid 42 ~orming a series of corresponding dots representative of the desired image.
The layers of insulating material 30 between the positive electrode members 14 should be as thin as possible so as to provide a continuous image and not one which is streaked. The layer of insulating material 40 surrounding each protruding element 32 should also be as thin as possible since the thinner the la~er 40 the faster is the speed of electro-coagulation.
Instead of having matrix elements 16 each formed with a single centrally disposed protruding element 32 as shown in Fig. 5, ;t is of course also posslble to provide matrix elements 16' each formed with a plurality of spaced-apart elements 32 as represented in the embodiment illustrated in Fig. 6. Such an arrange-ment enables one to produce an image having a more uniform tone repartition.
With the image reproduction system described above, it has been observed that the power required to /~
ii77~
produce coagulation over a square surface area of about 125 ,u x 125 ~ is the charge of an electrolytic capacitor of 2 micro farads at 50 volts. In o-ther words, using a power generator of 25 wat-ts (50 V, 500 mA), one can produce about 100,000 dots per second.
Although the dot matrix prlnter 10 has been illustrated as having a planar display surface, it is apparent that the whole surfaces of the positive electrode members 14 which constitute the display surface of the printer 10 need not be planar, provided however that the electrode active surfaces of each matrix element be planar and extend in a substantially common plane.
Thus, for example, a cylindrical dot matrix printer could be designed in which each matrix element would have the required characteristic just mentioned.
In order to reproduce an image with the system ~ust described, a layer of a liquid colloidal Q~7~
dispersion containing a colloid such as ge:Latin or albumin, water and an electrolyte such as potassium chloride, and having a suhstantially uniform temperature throughout -the layer, is applied over the surface of the dot matrix printer 10. The sweeping devices 18 and 18' and the counter 24 are then activated so as to elec-trically energize the electrodes of selected ones of the matrix elements 16 and thereby cause selective coagula-tion and adherence of the colloid onto the positive electrode active surfaces 38 of the selected matrix elements, the coagulated colloid 42 ~orming a series of corresponding dots representative of the desired image.
The layers of insulating material 30 between the positive electrode members 14 should be as thin as possible so as to provide a continuous image and not one which is streaked. The layer of insulating material 40 surrounding each protruding element 32 should also be as thin as possible since the thinner the la~er 40 the faster is the speed of electro-coagulation.
Instead of having matrix elements 16 each formed with a single centrally disposed protruding element 32 as shown in Fig. 5, ;t is of course also posslble to provide matrix elements 16' each formed with a plurality of spaced-apart elements 32 as represented in the embodiment illustrated in Fig. 6. Such an arrange-ment enables one to produce an image having a more uniform tone repartition.
With the image reproduction system described above, it has been observed that the power required to /~
ii77~
produce coagulation over a square surface area of about 125 ,u x 125 ~ is the charge of an electrolytic capacitor of 2 micro farads at 50 volts. In o-ther words, using a power generator of 25 wat-ts (50 V, 500 mA), one can produce about 100,000 dots per second.
Although the dot matrix prlnter 10 has been illustrated as having a planar display surface, it is apparent that the whole surfaces of the positive electrode members 14 which constitute the display surface of the printer 10 need not be planar, provided however that the electrode active surfaces of each matrix element be planar and extend in a substantially common plane.
Thus, for example, a cylindrical dot matrix printer could be designed in which each matrix element would have the required characteristic just mentioned.
Claims (23)
1. A method of reproducing an image by electro-coagulation of an electrolytically coagulable colloid, which comprises the steps of:
a) providing a plurality of negative and positive electrolytically inert electrodes electrically insulated from one another and arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity thereto;
b) applying a layer of a substantially liquid colloidal dispersion over the negative and positive electrode active surfaces of said matrix elements whereby the negative and positive electrode active surfaces are disposed on the same side of the layer of colloidal dispersion, said colloidal dispersion containing an electrolytically coagulable colloid, a liquid dispersing medium and a soluble electrolyte and having a substantially uniform temperature throughout said layer;
c) generating an electrical field between the negative and positive electrodes of selected ones of said matrix elements, said electrical field extending substantially parallel to the planar active surfaces of said negative and positive electrodes, whereby to cause selective coagulation and adherence of said colloid onto the positive electrode active surfaces of said selected matrix elements, thereby forming a series of corresponding dots representative of a desired image; and d) removing any remaining non-coagulated colloid.
a) providing a plurality of negative and positive electrolytically inert electrodes electrically insulated from one another and arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity thereto;
b) applying a layer of a substantially liquid colloidal dispersion over the negative and positive electrode active surfaces of said matrix elements whereby the negative and positive electrode active surfaces are disposed on the same side of the layer of colloidal dispersion, said colloidal dispersion containing an electrolytically coagulable colloid, a liquid dispersing medium and a soluble electrolyte and having a substantially uniform temperature throughout said layer;
c) generating an electrical field between the negative and positive electrodes of selected ones of said matrix elements, said electrical field extending substantially parallel to the planar active surfaces of said negative and positive electrodes, whereby to cause selective coagulation and adherence of said colloid onto the positive electrode active surfaces of said selected matrix elements, thereby forming a series of corresponding dots representative of a desired image; and d) removing any remaining non-coagulated colloid.
2. A method as claimed in claim 1, wherein the negative and positive electrodes of said matrix of dot-forming elements comprise respectively first and second sets of mutually electrically-insulated band-like electrode members disposed in parallel side-by-side relation, the negative electrode members of said first set extending transversely of the positive electrode members of said second set and being formed with a plurality of protruding conduc-tive elements which are spaced along the length thereof and each have a planar active end surface, the protruding elements of each negative electrode member extending through corres-ponding bores formed in said positive electrode members to terminate flush therewith such that the planar active end surface of each protruding element and a planar active surface portion of each positive electrode member adjacent each bore extend in a substantially common plane whereby to define said matrix elements, and wherein step (c) is effected by sequen-tially energizing the electrode members of one set and con-currently energizing selected ones of the electrode members of the other set.
3. A method as claimed in claim 2, wherein step (c) is carried out by sequentially energizing said positive electrode members and concurrently energizing selected ones of said negative electrode members.
4. A method as claimed in claim 2, wherein the concurrent selective energizing of the electrode members of the other set is effected by sweeping said electrode members and transmitting electrical pulses to selected ones thereof during sweeping.
5. A method as claimed in claim 4, wherein said electrical pulses are varied in voltage or time from one electrode member to another whereby to correspondingly vary the amount of coagulated colloid adhered onto the positive electrode active surfaces of said selected matrix elements.
6. A method as claimed in claim 1, further including the steps of coloring the coagulated colloid and transferring the colored coagulated colloid onto an end-use support.
7. A method as claimed in claim 1, further including the step of hardening the coagulated colloid whereby to use the hardened coagulated colloid for off-set lithographic printing.
8. A method as claimed in claim 1, wherein said colloid is a linear colloid having a molecular weight of about 10,000 to about 1,000,000.
9. A method as claimed in claim 8, wherein said colloid is a synthetic copolymer selected from the group consisting of polyacrylic acid, polyacrylamide, polyvinyl alcohol and derivatives thereof.
10. A method as claimed in claim 8, wherein said colloid has a molecular weight comprised between about 100,000 and about 500,000.
11. A method as claimed in claim 8, wherein said colloid is selected from the group consisting of animal and vegetable proteins and synthetic copolymers.
12. A method as claimed in claim 8, wherein said colloid is an animal protein selected from the group consisting of albumin and gelatin, said dispersing medium is water and said electrolyte is selected from the group consisting of potassium chloride, sodium chloride, calcium chloride, nickel chloride, lithium chloride, ammonium chloride, copper chloride and manganese sulfate.
13. A system for reproducing an image by electro-coagulation of an electrolytically coagulable colloid, which comprises:
- a plurality of negative and positive electrolyti-cally inert electrodes electrically insulated from one another and arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each said matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity there-to, said electrode active surfaces being adapted to receive thereover a layer of a substantially liquid colloidal dis-persion containing an electrolytically coagulable colloid, a liquid dispersing medium and a soluble electrolyte and having a substantially uniform temperature throughout said layer; and - means for electrically energizing the negative and positive electrodes of selected ones of said matrix elements to cause selective coagulation and adherence of said colloid onto the positive electrode active surfaces of said selected matrix elements and to thereby form a series of corresponding dots representative of a desired image.
- a plurality of negative and positive electrolyti-cally inert electrodes electrically insulated from one another and arranged to define a matrix of dot-forming elements, the negative and positive electrodes of each said matrix element having respective planar active surfaces with the negative electrode active surface extending in the same plane as the positive electrode active surface and in close proximity there-to, said electrode active surfaces being adapted to receive thereover a layer of a substantially liquid colloidal dis-persion containing an electrolytically coagulable colloid, a liquid dispersing medium and a soluble electrolyte and having a substantially uniform temperature throughout said layer; and - means for electrically energizing the negative and positive electrodes of selected ones of said matrix elements to cause selective coagulation and adherence of said colloid onto the positive electrode active surfaces of said selected matrix elements and to thereby form a series of corresponding dots representative of a desired image.
14. A system as claimed in claim 13, wherein the negative and positive electrodes of said matrix of dot-forming elements comprise respectively first and second sets of mutually electrically-insulated band-like electrode members disposed in parallel side-by-side relation, the negative electrode members of said first set extending transversely of the positive electrode members of said second set and being formed with a plurality of protruding conductive elements which are spaced along the length thereof and each have a planar active end surface, the protruding elements of each negative electrode member extending through corresponding bores formed in said positive electrode members to terminate flush therewith such that the planar active end surface of each protruding element and a planar active surface portion of each positive electrode member adjacent each bore extend in a substantially common plane whereby to define said matrix elements, and wherein said electrical energizing means include means for sequentially energizing the electrode members of one set and means for concurrently energizing selected ones of the electrode members of the other set.
15. A system as claimed in claim 14, wherein said sequential energizing means comprises a sweeping device connected to a positive terminal of a direct current power supply and adapted to sweep said positive electrode members, and wherein said selective energiz-ing means comprises a further sweeping device connected to a negative terminal of said power supply for sweeping said negative electrode members and a counting device coupled to said further sweeping device for transmitting electrical pulses to selected ones of said negative electrode members during operation of said further coupling device.
16. A system as claimed in claim 15, further including modulating means for varying said electrical pulses in voltage or time from one negative electrode member to another whereby to correspondingly vary the amount of coagulated colloid adhered onto the positive electrode active surfaces of said selected matrix elements.
17. A system as claimed in claim 14, where-in each matrix element comprises a single said protruding element disposed substantially centrally thereof.
18. A system as claimed in claim 14, wherein each matrix element comprises a plurality of said protruding elements arranged in spaced-apart relation to provide an image having a uniform tone repartition.
19. A system as claimed in claim 17, where-in each matrix element has a square surface area of about 125 µ x 125 µ and wherein said single protrud-ing element is circular in cross-section and has a diameter of about 25 to 50 µ.
20. A system as claimed in claim 14, wherein each protruding element is electrically insulated from its adjacent positive electrode member by means of a layer of insulating material having a thickness of about 5 to 10 µ.
21. A system as claimed in claim 14, wherein said positive electrode members are electrically insulated from one another by means of a layer of insulating material having a thickness of about 10 to 25 µ.
22. A system as claimed in claim 21, wherein said layer of insulating material has a thickness of about 10 µ.
23. A system as claimed in claim 13, wherein said matrix of dot-forming elements comprises about 40,000 dot-forming elements per square inch.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000454450A CA1205778A (en) | 1984-05-16 | 1984-05-16 | Image reproduction by in plane electro-coagulation of a colloid |
| ZA853470A ZA853470B (en) | 1984-05-16 | 1985-05-08 | Image reproduction by in plane electro-coagulation of a colloid |
| AT85105683T ATE46659T1 (en) | 1984-05-16 | 1985-05-09 | IMAGE REPRODUCTION BY AREA ELECTROCOAGULATION OF COLLOIDS. |
| EP85105683A EP0161633B1 (en) | 1984-05-16 | 1985-05-09 | Image reproduction by in plane electro-coagulation of a colloid |
| DE8585105683T DE3573234D1 (en) | 1984-05-16 | 1985-05-09 | Image reproduction by in plane electro-coagulation of a colloid |
| KR1019850003253A KR850008649A (en) | 1984-05-16 | 1985-05-13 | Image Reproducing Method by Colloidal Electrocoagulation in Plane and Its System |
| AU42466/85A AU572293B2 (en) | 1984-05-16 | 1985-05-14 | Image reproduction by in plane electro-coagulation of a colloid |
| JP60102803A JPS60259489A (en) | 1984-05-16 | 1985-05-16 | Method of regenerating image through electrocoagulation in plane of colloid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000454450A CA1205778A (en) | 1984-05-16 | 1984-05-16 | Image reproduction by in plane electro-coagulation of a colloid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1205778A true CA1205778A (en) | 1986-06-10 |
Family
ID=4127877
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000454450A Expired CA1205778A (en) | 1984-05-16 | 1984-05-16 | Image reproduction by in plane electro-coagulation of a colloid |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0161633B1 (en) |
| JP (1) | JPS60259489A (en) |
| KR (1) | KR850008649A (en) |
| AT (1) | ATE46659T1 (en) |
| AU (1) | AU572293B2 (en) |
| CA (1) | CA1205778A (en) |
| DE (1) | DE3573234D1 (en) |
| ZA (1) | ZA853470B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1279603C (en) * | 1986-02-20 | 1991-01-29 | Adrien Castegnier | Monochromic and polychromic printing of an image reproduced by electro-coagulation of a colloid |
| CA1249238A (en) * | 1986-07-18 | 1989-01-24 | Adrien Castegnier | Method of preventing undesirable gas generation between electrodes of an electrocoagulation printing system |
| JPH0641221B2 (en) * | 1988-01-25 | 1994-06-01 | キヤノン株式会社 | Image forming method, recording material and image forming apparatus |
| US5055380A (en) * | 1989-12-18 | 1991-10-08 | Eastman Kodak Company | Method of forming a color-differentiated image utilizing a metastable aggregated group ib metal colloid material |
| CA2178679C (en) * | 1996-06-10 | 1999-08-31 | Adrien Castegnier | Electrocoagulation printing apparatus |
| WO1998029253A1 (en) * | 1996-12-30 | 1998-07-09 | Toyo Ink Manufacturing Co., Ltd. | Electric coagulation printing method and apparatus |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2869965A (en) * | 1954-12-30 | 1959-01-20 | Ibm | Electro-sensitive digital data plotter |
| US3752746A (en) * | 1972-02-25 | 1973-08-14 | A Castegnier | Electrolytic printing method and system |
| US3892645A (en) * | 1973-06-06 | 1975-07-01 | Adrien Castegnier | Printing method and system by gelatin coagulation |
| CA1250249A (en) * | 1984-05-11 | 1989-02-21 | Adrien Castegnier | Printing method by electrolytic colloid coagulation and colloid composition therefor |
-
1984
- 1984-05-16 CA CA000454450A patent/CA1205778A/en not_active Expired
-
1985
- 1985-05-08 ZA ZA853470A patent/ZA853470B/en unknown
- 1985-05-09 DE DE8585105683T patent/DE3573234D1/en not_active Expired
- 1985-05-09 AT AT85105683T patent/ATE46659T1/en not_active IP Right Cessation
- 1985-05-09 EP EP85105683A patent/EP0161633B1/en not_active Expired
- 1985-05-13 KR KR1019850003253A patent/KR850008649A/en not_active Application Discontinuation
- 1985-05-14 AU AU42466/85A patent/AU572293B2/en not_active Ceased
- 1985-05-16 JP JP60102803A patent/JPS60259489A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| ATE46659T1 (en) | 1989-10-15 |
| KR850008649A (en) | 1985-12-21 |
| AU4246685A (en) | 1985-11-21 |
| EP0161633A3 (en) | 1987-08-05 |
| DE3573234D1 (en) | 1989-11-02 |
| JPH0473386B2 (en) | 1992-11-20 |
| EP0161633A2 (en) | 1985-11-21 |
| JPS60259489A (en) | 1985-12-21 |
| EP0161633B1 (en) | 1989-09-27 |
| ZA853470B (en) | 1985-12-24 |
| AU572293B2 (en) | 1988-05-05 |
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| MKEX | Expiry |