EP0091073B1 - Electrostatic printing head - Google Patents
Electrostatic printing head Download PDFInfo
- Publication number
- EP0091073B1 EP0091073B1 EP83103115A EP83103115A EP0091073B1 EP 0091073 B1 EP0091073 B1 EP 0091073B1 EP 83103115 A EP83103115 A EP 83103115A EP 83103115 A EP83103115 A EP 83103115A EP 0091073 B1 EP0091073 B1 EP 0091073B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- electrodes
- recording medium
- print head
- insulating film
- drum
- 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
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- 238000003825 pressing Methods 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 2
- 239000012858 resilient material Substances 0.000 claims 2
- 239000002184 metal Substances 0.000 description 8
- 239000000758 substrate Substances 0.000 description 6
- 239000011810 insulating material Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 3
- 239000013013 elastic material Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000003754 machining Methods 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 241001417494 Sciaenidae Species 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 230000001850 reproductive effect Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/385—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material
- B41J2/39—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material using multi-stylus heads
- B41J2/395—Structure of multi-stylus heads
Definitions
- the present invention relates to electrostatic image printing on a recording medium; it relates more particularly to an electrostatic printhead with multiple electrodes which, brought to high voltage, create by electrical discharge in air a latent electrostatic image on the recording medium moving past them.
- This printing mode therefore requires that an air slot be made between the electrodes of the print head and the facing surface of the recording medium on which this latent image is printed.
- an air slot be made between the electrodes of the print head and the facing surface of the recording medium on which this latent image is printed.
- the recording medium consists of a conductive paper substrate carrying on one of its faces a dielectric layer a few micrometers thick
- the natural roughness of the paper or the use of spacers embedded in the dielectric layer makes it possible to obtain this discharge slot between the electrodes and the dielectric surface.
- the recording medium has an almost smooth surface state, which is particularly the case when it is constituted by a dielectric film, or a metal drum covered with a dielectric layer, used as an intermediate medium on which is generated latent image which will later be transferred, after development, to a final support, it is necessary to provide, at the level of the print head itself, means creating this discharge slot.
- Document FR-A-2138 789 describes a device for generating charge images, with geometrically limited space for the reproductive parts of an arrangement of electrodes, located opposite the highly ohmic dielectric layer of the information carrier.
- an arrangement of electrodes is formed by distinct conductive styles and is embedded in an insulating material having, at this arrangement, a hollow defined at the diameter of the styles, or, as a variant, is formed by a conductive style in the form of a symbol and is embedded in an insulating material, the hollow of which is defined in the profile of the symbol, so that the lower surface of the electrode arrangement does not lie flush with the lower surface of the insulating material and that this hollow then constitutes the essential discharge slot.
- an arrangement of electrodes is constituted by a thin very conductive layer covering the walls of bores or openings made in an insulating material, or alternatively, by profiled recesses made in a conductive material ; also in these two cases, the discharge inside the bores, openings or recesses makes it possible to create the load images.
- electrostatic heads designed so that the necessary electrical discharge slot is defined therein do not lend themselves to easy industrial production. In addition, they do not seem adaptable to rapid and high resolution printing (up to 8 points per millimeter) obtained by multi-electrode electrostatic heads (1,728 electrodes), currently operating with a paper covered with a dielectric layer with surface irregularities, which use printed circuit technology to define, by the end portions of conductive tracks, the functions of electrodes.
- the object of the present invention is to produce a printhead in which an electrical discharge slot is provided at its electrodes to allow it to operate with a recording medium with a smooth surface state and in which the technology is used.
- printed circuits to define a linear arrangement of electrodes compatible with very high printing performance.
- Another object of the present invention is to keep the distance separating each of the electrodes from the recording medium constant, regardless of defects which would normally cause variations in this distance.
- the subject of the present invention is therefore an electrostatic printhead bearing on a recording medium with an almost smooth surface state, comprising a plurality of electrodes disposed recessed relative to the surface of said recording medium to define therebetween and said surface a discharge slot responding to the Pashen curves in the air, characterized in that said electrodes are constituted by the end portions of conductive tracks of a flexible printed circuit, and that said printed circuit is mounted, at the very less at the level of the electrodes and of the adjacent parts of the tracks, the back pressed against a convex support structure, and with its outer face coated, in outside the end portions of the conductive tracks, an insulating film of selected thickness so that by pressing on the recording medium it maintains said slot between said electrodes and said recording medium.
- Such a head is therefore particularly suitable for an industrial production of heads with high printing performance on a recording medium with a smooth surface state such as a metal drum covered with a thin dielectric layer or dielectric strip running on a metal roller serving counter electrode.
- the supporting structure of the printed circuit or the metal roller on which the recording medium runs when the latter is a dielectric strip, is made of elastic material and is subjected to a pressure means holding the recording medium and the insulating film applied one against the other.
- the electrostatic print head comprises a flexible printed circuit 1, with conductive tracks such as 2 printed on one of the faces of the flexible substrate organized in two distinct networks of tracks, the parts of which facing terminals are aligned in two parallel rows and constitute the printing electrodes (not referenced in these two figures). It further comprises an insulating film 3, 10 to 20 fJ.m thick deposited on the printed face of circuit 1, at least outside the end portions of the tracks constituting the electrodes and the interval between the two rows of electrodes which are therefore not covered. This film 3 will advantageously be divided into two parts deposited identically on one and the other of these two networks of conductive tracks.
- the printed circuit 1 is mounted with the back pressed against a supporting structure formed by a drum 4, so that the rows of electrodes defined on the external face of the printed circuit are arranged substantially along two generatrices of this drum.
- the drum 4 will advantageously be chosen of small diameter, of the order of 1 to a few centimeters, to obtain a head of small thickness but also so that it defines at the level of. electrodes a very convex convex profile which will be possibly deformable according to the choice which will be made as for the material constituting the drum.
- the drum 4 is associated with an auxiliary support structure formed here by a U-shaped support 5.
- the lateral branches of this support receive the portions of the printed circuit 1 which are situated on either side of its median portion held on the drum and which define the connection ends of the conductive tracks to an electrode control circuit (this external control circuit of the problem treated by the present invention is therefore neither illustrated nor described).
- This U-shaped support can be secured to the axis 6 of the drum 4.
- the printed circuit against the drum 4 and against the support 5 can be maintained by means of an adhesive or an adhesive polyester film.
- these tracks are organized in two distinct networks and terminate in the longitudinal portion of the printed circuit, concerns the two networks, respectively in two parallel rows separated from each other by a distance x equal to one or a few printing lines.
- these electrodes 8 are of regular pitch along their row and are offset between them by a half-step from one row to another.
- the conductive tracks 2 of one and the other of the two networks extend respectively towards one and the other of the longitudinal edges of the printed circuit and end, advantageously in a stepped manner by group for obvious facilities for connection with the control circuit of the electrodes to be connected to these so-called connection ends.
- the conductive tracks are organized in groups of sixteen and that the connection ends for each group, noted 8-1, ... 8-8, 8-9 ... 8- 16 for one of the groups, are effectively tiered.
- These ends have moreover been advantageously brought into two parallel lines along which they are regularly distributed by being two by two facing each other, or, in a variant not illustrated, offset from one line to another.
- the printed circuit portions including these connection ends, or at least the connection ends themselves, are not covered by the insulating film 3.
- the conductive tracks can be arranged in different groups, taking into account the number of electrodes that the head comprises (for example 1728 electrodes), of the control circuit which will be associated with the print head and of facilities for connecting this control circuit to the ends of these tracks.
- the printhead by mounting the printed circuit on a convex surface, it is the terminal portions of the tracks, and not their front end faces which constitute the electrodes.
- the dimensions of these electrodes are then limited, depending on the desired size of the individual dots to be printed on the one hand by the width of the tracks, but also by the insulating film 3 appropriately positioned relative to the ends correspondan- - your tracks for leave only the desired lengths of end portions serving as printing electrodes uncovered.
- the insulating film 3 by the extra thickness it creates on either side of the electrodes, constitutes the bearing face of the head on the recording medium, with respect to which the electrodes remain distant, and cleaning between the electrodes and the recording medium, whatever the even perfectly smooth surface condition that it may have, the ion discharge slot necessary for the generation of latent images.
- the writing of the latent image is then carried out by placing the individual electrodes and the metal drum at suitable potentials creating an ionic discharge in the air layer between the individual electrodes and the dielectric layer, normally defined by the thickness of the film. insulator 3 (from 10 to 20 fJ.m).
- the drum 4 of the support structure of the head will advantageously be made of an elastic material and will receive a pressure P, for example of the order of 1 kg applied to its axis 6.
- the flexible print head comes to be applied strictly against the rigid drum 10 and adapts to its periphery.
- This arrangement makes it possible to get rid of any machining defects in this recording drum which would affect the thickness of the air layer along the rows of electrodes facing the dielectric layer, by compensating for them. by crushing the printhead which ensures positioning of each of the electrodes at a constant distance opposite the periphery of the printing drum.
- the film of dielectric material 11, possibly electrostatically charged by an illustrated corona device 13 and mounted opposite a metal guide 15, is driven in front of the print head while being supported, at its level for a conductive roller 14 serving as a counter-electrode and then belonging to the print head.
- the drum 4 of the support structure of the head will also be made of flexible material and subjected to a pressure P applying it rigorously against the periphery of the fixed roller 14 or, in the illustrated variant, it is the roller 14 which will be deformable and applied against the drum 4 then rigid and fixed with respect to it.
Landscapes
- Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
- Electrophotography Using Other Than Carlson'S Method (AREA)
- Dot-Matrix Printers And Others (AREA)
Description
La présente invention concerne l'impression d'image électrostatique sur un support d'enregistrement ; elle porte plus particulièrement sur une tête d'impression électrostatique à électrodes multiples qui, portées à haute tension, créent par décharge électrique dans l'air une image électrostatique latente sur le support d'enregistrement défilant devant elles.The present invention relates to electrostatic image printing on a recording medium; it relates more particularly to an electrostatic printhead with multiple electrodes which, brought to high voltage, create by electrical discharge in air a latent electrostatic image on the recording medium moving past them.
Ce mode d'impression exige donc qu'une fente d'air soit ménagée entre les électrodes de la tête d'impression et la surface en regard du support d'enregistrement sur laquelle est imprimée cette image latente. En effet, pour générer, à l'aide d'une décharge dans un gaz, une image de charge électrostatique, outre la tension suffisamment élevée à laquelle sont portées les électrodes sélectionnées, il est courant d'adopter une fente de décharge d'environ 10 lim répondant aux courbes de Pashen de décharge dans les gaz, en l'occurrence dans l'air à pression atmosphérique (cf. par exemple FR-A-2 205 850).This printing mode therefore requires that an air slot be made between the electrodes of the print head and the facing surface of the recording medium on which this latent image is printed. Indeed, to generate, by means of a discharge in a gas, an image of electrostatic charge, in addition to the sufficiently high voltage to which the selected electrodes are brought, it is common to adopt a discharge slot of approximately 10 li m responding to the Pashen curves of discharge in gases, in this case in air at atmospheric pressure (cf. for example FR-A-2 205 850).
Lorsque le support d'enregistrement est constitué par un substrat conducteur en papier portant sur l'une de ses faces une couche diélectrique de quelques micromètres d'épaisseur, la rugosité naturelle du papier ou l'utilisation d'éléments d'écartement noyés dans la couche diélectrique permet d'obtenir cette fente de décharge entre les électrodes et la surface diélectrique. Cependant, lorsque le support d'enregistrement présente un état de surface quasiment lisse, ce qui est tout particulièrement le cas quand il est constitué par un film diélectrique, ou un tambour métallique recouvert d'une couche diélectrique, utilisé comme support intermédiaire sur lequel est générée l'image latente qui sera ultérieurement transférée, après développement, sur un support final, il est nécessaire de prévoir, au niveau de la tête d'impression elle-même, des moyens créant cette fente de décharge.When the recording medium consists of a conductive paper substrate carrying on one of its faces a dielectric layer a few micrometers thick, the natural roughness of the paper or the use of spacers embedded in the dielectric layer makes it possible to obtain this discharge slot between the electrodes and the dielectric surface. However, when the recording medium has an almost smooth surface state, which is particularly the case when it is constituted by a dielectric film, or a metal drum covered with a dielectric layer, used as an intermediate medium on which is generated latent image which will later be transferred, after development, to a final support, it is necessary to provide, at the level of the print head itself, means creating this discharge slot.
Le document FR-A-2138 789 décrit un dispositif pour engendrer des images de charge, à espace limité géométriquement pour les parties reproductrices d'un agencement d'électrodes, situées en regard de la couche diélectrique fortement ohmique du porteur d'information. Dans un mode de réalisation donné dans ce document, un agencement d'électrodes est formé par des styles conducteurs distincts et est noyé dans un matériau isolant présentant, au niveau, de cet agencement un creux défini au diamètre des styles, ou, en variante, est formé par un style conducteur sous forme d'un symbole et est noyé dans un matériau isolant dont le creux est défini au profilé du symbole, de sorte que la surface inférieure de l'agencement d'électrodes n'affleure pas la surface inférieure du matériau isolant et que ce creux constitue alors la fente de décharge indispensable. Dans un autre mode de réalisation donné, un agencement d'électrodes est constitué par une fine couche très conductrice revêtant les parois d'alésages ou ouvertures pratiqués dans un matériau isolant, ou encore, en variante, par des évidements profilés pratiqués dans un matériau conducteur ; dans ces deux cas aussi, la décharge à l'intérieur des alésages, ouvertures ou évidements permet de créer les images de charge.Document FR-A-2138 789 describes a device for generating charge images, with geometrically limited space for the reproductive parts of an arrangement of electrodes, located opposite the highly ohmic dielectric layer of the information carrier. In an embodiment given in this document, an arrangement of electrodes is formed by distinct conductive styles and is embedded in an insulating material having, at this arrangement, a hollow defined at the diameter of the styles, or, as a variant, is formed by a conductive style in the form of a symbol and is embedded in an insulating material, the hollow of which is defined in the profile of the symbol, so that the lower surface of the electrode arrangement does not lie flush with the lower surface of the insulating material and that this hollow then constitutes the essential discharge slot. In another given embodiment, an arrangement of electrodes is constituted by a thin very conductive layer covering the walls of bores or openings made in an insulating material, or alternatively, by profiled recesses made in a conductive material ; also in these two cases, the discharge inside the bores, openings or recesses makes it possible to create the load images.
Ces têtes électrostatiques conçues pour qu'y soit définie la fente de décharge électrique nécessaire ne se prêtent cependant pas à une réalisation industrielle aisée. De plus, elles ne semblent pas adaptables à une impression rapide et de haute résolution (allant jusqu'à 8 points au millimètre) obtenue par des têtes électrostatiques multiélectrodes (1 728 électrodes), fonctionnant actuellement avec un papier recouvert d'une couche diélectrique à irrégularités de surface, qui utilisent la technologie des circuits imprimés pour définir, par les parties terminales de pistes conductrices, les fonctions d'électrodes.These electrostatic heads designed so that the necessary electrical discharge slot is defined therein do not lend themselves to easy industrial production. In addition, they do not seem adaptable to rapid and high resolution printing (up to 8 points per millimeter) obtained by multi-electrode electrostatic heads (1,728 electrodes), currently operating with a paper covered with a dielectric layer with surface irregularities, which use printed circuit technology to define, by the end portions of conductive tracks, the functions of electrodes.
Dans ce type de têtes électrostatiques utilisant la technologie des circuits imprimés ce sont les parties frontales des pistes conductrices affleurant ou même débordant sur la tranche du substrat qui constituent les électrodes. De manière courante, on réalise une telle tête d'impression à électrodes en deux lignes en assemblant dos à dos deux substrats porteurs de pistes imprimées US-A-4180 824 ou les deux parties d'un substrat unique plié et découpé (US-A-4 287 525). Ces têtes ne fonctionnent cependant pas avec un support d'enregistrement à état de surface trop lisse.In this type of electrostatic head using printed circuit technology, it is the front portions of the conductive tracks which are flush or even projecting over the edge of the substrate which constitute the electrodes. Usually, such an electrode printhead is produced in two lines by assembling back to back two substrates carrying printed tracks US-A-4180 824 or the two parts of a single folded and cut substrate (US-A -4,287,525). These heads, however, do not work with a recording medium with a too smooth surface state.
La présente invention a pour but de réaliser une _ tête d'impression dans laquelle est ménagée une fente de décharge électrique au niveau de ses électrodes pour permettre son fonctionnement avec un support d'enregistrement à état de surface lisse et dans laquelle on utilise la technologie des circuits imprimés pour définir un agencement linéaire d'électrodes compatible avec de très hautes performances d'impression.The object of the present invention is to produce a printhead in which an electrical discharge slot is provided at its electrodes to allow it to operate with a recording medium with a smooth surface state and in which the technology is used. printed circuits to define a linear arrangement of electrodes compatible with very high printing performance.
La présente invention a également pour but de maintenir constante la distance séparant chacune des électrodes du support d'enregistrement, indépendamment de défauts qui entraîneraient normalement des variations de cette distance.Another object of the present invention is to keep the distance separating each of the electrodes from the recording medium constant, regardless of defects which would normally cause variations in this distance.
La présente invention a donc pour objet une tête d'impression électrostatique portant sur un support d'enregistrement à état de surface quasiment lisse, comportant une pluralité d'électrodes disposées en retrait par rapport à la surface dudit support d'enregistrement pour définir entre elles et ladite surface une fente de décharge répondant aux courbes de Pashen dans l'air, caractérisée par le fait que lesdites électrodes sont constituées par les parties terminales de pistes conductrices d'un circuit imprimé souple, et que ledit circuit imprimé est monté, tout au moins au niveau des électrodes et des parties adjacentes des pistes, le dos plaqué contre une structure porteuse convexe, et a sa face externe revêtue, en dehors des parties terminales des pistes conductrices, d'un film isolant d'épaisseur choisie pour qu'en s'appuyant sur le support d'enregistrement il maintienne ladite fente entre lesdites électrodes et ledit support d'enregistrement.The subject of the present invention is therefore an electrostatic printhead bearing on a recording medium with an almost smooth surface state, comprising a plurality of electrodes disposed recessed relative to the surface of said recording medium to define therebetween and said surface a discharge slot responding to the Pashen curves in the air, characterized in that said electrodes are constituted by the end portions of conductive tracks of a flexible printed circuit, and that said printed circuit is mounted, at the very less at the level of the electrodes and of the adjacent parts of the tracks, the back pressed against a convex support structure, and with its outer face coated, in outside the end portions of the conductive tracks, an insulating film of selected thickness so that by pressing on the recording medium it maintains said slot between said electrodes and said recording medium.
Une telle tête est donc particulièrement adaptée à une réalisation industrielle de têtes à hautes performances d'impression sur un support d'enregistrement à état de surface lisse tel que tambour métallique recouvert d'une fine couche diélectrique ou bande diélectrique défilant sur un rouleau métallique servant de contre-électrode.Such a head is therefore particularly suitable for an industrial production of heads with high printing performance on a recording medium with a smooth surface state such as a metal drum covered with a thin dielectric layer or dielectric strip running on a metal roller serving counter electrode.
De préférence, la structure porteuse du circuit imprimé ou le rouleau métallique sur lequel défile le support d'enregistrement lorsque celui-ci est une bande diélectrique, est en matériau élastique et est soumis à un moyen de pression maintenant le support d'enregistrement et le film isolant appliqués l'un contre l'autre.Preferably, the supporting structure of the printed circuit or the metal roller on which the recording medium runs when the latter is a dielectric strip, is made of elastic material and is subjected to a pressure means holding the recording medium and the insulating film applied one against the other.
Dans ces conditions, par déformation du matériau élastique on compense d'éventuelles imperfections d'usinage que peut présenter le tambour métallique du support d'enregistrement ou le rouleau en appui contre lequel défile le support d'enregistrement.Under these conditions, by deformation of the elastic material, any machining imperfections that the metal drum of the recording medium or the roller in abutment against which the recording medium runs can be compensated for.
L'invention sera mieux comprise à l'aide de la description détaillée d'un exemple de réalisation illustré dans le dessin ci-annexé. Dans ce dessin :
- les figures 1 et 2 représentent schématiquement une tête d'impression électrostatique selon l'invention, pour l'impression d'images électrostatiques latentes sur un tambour recouvert d'un matériau diélectrique et sur une bande en matériau diélectrique, respectivement,
- la figure 3 illustre schématiquement des éléments rentrant dans ladite tête d'impression,
- la figure 4 représente à échelle agrandie la zone notée IV de cette figure 3.
- FIGS. 1 and 2 schematically represent an electrostatic printing head according to the invention, for printing latent electrostatic images on a drum covered with a dielectric material and on a strip of dielectric material, respectively,
- FIG. 3 schematically illustrates elements entering said print head,
- FIG. 4 represents on an enlarged scale the zone denoted IV of this FIG. 3.
En regard des figures 1 et 2, on voit que la tête d'impression électrostatique comporte un circuit imprimé souple 1, à pistes conductrices telles que 2 imprimées sur l'une des faces du substrat souple organisées en deux réseaux distincts de pistes dont les parties terminales en regard sont alignées en deux rangées parallèles et constituent les électrodes d'impression (non référen- ciées dans ces deux figures). Elle comporte, en outre un film isolant 3, de 10 à 20 fJ.m d'épaisseur déposé sur la face imprimée du circuit 1, tout au moins en dehors des parties terminales des pistes constituant les électrodes et de l'intervalle entre les deux rangées d'électrodes qui sont donc non recouverts. Ce film 3 sera avantageusement divisé en deux parties déposées identiquement sur l'un et l'autre de ces deux réseaux de pistes conductrices.With reference to FIGS. 1 and 2, it can be seen that the electrostatic print head comprises a flexible printed
Le circuit imprimé 1 est monté le dos plaqué contre une structure porteuse formée par un tambour 4, de sorte que les rangées d'électrodes définies sur la face externe du circuit imprimé soient disposées sensiblement selon deux génératrices de ce tambour. Le tambour 4 sera avantageusement choisi de faible diamètre, de l'ordre de 1 à quelques centimètres, pour obtenir une tête de faible épaisseur mais également pour qu'il définisse au niveau des. électrodes un profil convexe très bombé qui sera éventuellement déformable selon le choix qui sera fait quant au matériau constituant le tambour.The printed
Au tambour 4 est associée une structure porteuse auxiliaire formée ici par un support en U 5. Les branches latérales de ce support reçoivent les portions du circuit imprimé 1 qui sont situées de part et d'autre de sa portion médiane maintenue sur le tambour et qui définissent les extrémités de connexion des pistes conductrices à un circuit de commande des électrodes, (ce circuit de commande extérieur du problème traité par la présente invention n'étant donc ni illustré ni décrit). Ce support en U pourra être solidaire de l'axe 6 du tambour 4. Le maintien du circuit imprimé contre le tambour 4 et contre le support 5 pourra être assuré au moyen d'une colle ou d'un film en polyester adhésif.The drum 4 is associated with an auxiliary support structure formed here by a U-shaped
En regard des figures 3 et 4 dans lesquelles on a schématisé l'agencement des pistes conductrices 2 sur le substrat de circuit imprimé, on voit que ces pistes sont organisées en deux réseaux distincts et aboutissent dans la portion longitudinale du circuit imprimé, en ce qui concerne les deux réseaux, respectivement en deux rangées parallèles séparées l'une de l'autre d'une distance x égale à une ou à quelques lignes d'impression. Les portions terminales des pistes 2, définissant ces deux rangées, non recouvertes par le film isolant 3 déposé sur la face imprimée du circuit 1, constituent les électrodes 8 de la tête d'impression ; la taille des points inscrits sera donc, dans une dimension, déterminée par ces portions non recouvertes par le film isolant. Indépendamment de l'organisation des pistes 2, ces électrodes 8 sont à pas régulier le long de leur rangée et sont décalées entre elles d'un demi-pas d'une rangée à l'autre.With reference to FIGS. 3 and 4 in which the arrangement of the
A partir des extrémités constituant les électrodes 8 les pistes conductrices 2 de l'un et l'autre des deux réseaux s'étendent respectivement vers l'un et l'autre des bords longitudinaux du circuit imprimé et se terminent, avantageusement de manière étagée par groupe pour des facilités évidentes de connexion avec le circuit de commande des électrodes à raccorder sur ces extrémités dites de connexion. Ainsi en regard de la figure 3, on voit que les pistes conductrices sont organisées par groupes de seize et que les extrémités de connexion pour chaque groupe, notées 8-1, ... 8-8, 8-9 ... 8-16 pour l'un des groupes, sont effectivement étagées. Ces extrémités ont de plus été avantageusement ramenées en deux lignes parallèles le long desquelles elles sont régulièrement réparties en étant deux par deux en regard, ou, en variante non illustrée, décalées d'une ligne à l'autre. Les portions de circuit imprimé incluant ces extrémités de connexions, ou tout au moins les extrémités de connexion elles-mêmes ne sont pas recouvertes par le film isolant 3.From the ends constituting the
Bien entendu dans la pratique, les pistes conductrices pourront être agencées en des groupes différents, en tenant compte du nombre d'électrodes que comporte la tête (par exemple 1728 électrodes), du circuit de commande qui sera associé à la tête d'impression et des facilités de raccordement de ce circuit de commande sur les extrémités de ces pistes.Of course in practice, the conductive tracks can be arranged in different groups, taking into account the number of electrodes that the head comprises (for example 1728 electrodes), of the control circuit which will be associated with the print head and of facilities for connecting this control circuit to the ends of these tracks.
Dans la tête d'impression selon l'invention, par le montage du circuit imprimé sur une surface convexe, ce sont les portions terminales des pistes, et non leurs faces frontales d'extrémité qui constituent les électrodes. Les dimensions de ces électrodes sont alors limitées, en fonction de la taille souhaitée des points individuels à imprimer, d'une part par la largeur des pistes mais également par le film isolant 3 convenablement positionné par rapport aux extrémités correspondan-- tes des pistes pour ne laisser non recouvertes que les seules longueurs souhaitées de portions terminales servant d'électrodes d'impression.In the printhead according to the invention, by mounting the printed circuit on a convex surface, it is the terminal portions of the tracks, and not their front end faces which constitute the electrodes. The dimensions of these electrodes are then limited, depending on the desired size of the individual dots to be printed on the one hand by the width of the tracks, but also by the
De plus dans la tête d'impression, le film isolant 3, par la surépaisseur qu'il crée de part et d'autre des électrodes, constitue la face d'appui de la tête sur le support d'enregistrement, par rapport auquel les électrodes demeurent distantes, et ménage entre les électrodes et le support d'enregistrement, quel que soit l'état de surface même parfaitement lisse qu'il peut présenter, la fente de décharge ionique nécessaire à la génération d'images latentes.In addition in the print head, the
La description de la tête d'impression selon l'invention sera complétée en regard des figures 1 et 2, en fonction du type de support d'enregistrement utilisé, tel qu'un tambour métallique 10 recouvert d'une couche diélectrique, d'axe parallèle à celui du tambour de la tête (figure 1) ou un film diélectrique 11 (figure 2), présentant un état de surface relativement lisse.The description of the printhead according to the invention will be completed with reference to Figures 1 and 2, depending on the type of recording medium used, such as a
Dans la figure 1, la périphérie du tambour 10 recouvert d'une couche diélectrique, le cas échéant chargée électrostatiquement par un dispositif de corona illustré en 12, défile devant les deux rangées d'électrodes de la tête d'impression en appui par le film isolant 3 sur la couche diélectrique. L'écriture de l'image latente est alors réalisée par mise des électrodes individuelles et du tambour métallique aux potentiels convenables créant une décharge ionique dans la couche d'air entre les électrodes individuelles et la couche diélectrique, normalement définie par l'épaisseur du film isolant 3 (de 10 à 20 fJ.m).In FIG. 1, the periphery of the
Dans l'utilisation de la tête d'impression avec un tel support, le tambour 4 de la structure porteuse de la tête sera avantageusement réalisé en un matériau élastique et recevra une pression P, par exemple de l'ordre de 1 kg appliquée sur son axe 6.In the use of the print head with such a support, the drum 4 of the support structure of the head will advantageously be made of an elastic material and will receive a pressure P, for example of the order of 1 kg applied to its
Dans ces conditions, la tête d'impression rendue souple vient s'appliquer rigoureusement contre le tambour rigide 10 et s'adapte à sa périphérie. Cette disposition permet de s'affranchir d'éventuels défauts d'usinage de ce tambour d'enregistrement qui se répercuteraient sur l'épaisseur de la couche d'air le long des rangées d'électrodes en regard de la couche diélectrique, en les compensant par l'écrasement de la tête d'impression qui vient assurer un positionnement de chacune des électrodes à une distance constante en regard de la périphérie du tambour d'impression.Under these conditions, the flexible print head comes to be applied strictly against the
Dans la figure 2, le film en matériau diélectrique 11, éventuellement chargé électrostatiquement par un dispositif de corona illustré 13 et monté en regard d'un guide métallique 15, est entraîné devant la tête d'impression tout en étant supporté, à son niveau pour un rouleau conducteur 14 servant de contre-électrode et appartenant alors à la tête d'impression.In FIG. 2, the film of
Dans ce cas d'utilisation de la tête d'impression avec un support d'enregistrement souple, le tambour 4 de la structure porteuse de la tête sera également réalisé en matériau souple et soumis à une pression P l'appliquant rigoureusement contre la périphérie du rouleau fixe 14 ou, en variante illustrée, c'est le rouleau 14 qui sera déformable et appliqué contre le tambour 4 alors rigide et fixe par rapport à lui.In this case of use of the print head with a flexible recording medium, the drum 4 of the support structure of the head will also be made of flexible material and subjected to a pressure P applying it rigorously against the periphery of the
Dans ces conditions on retrouve le même avantage de positionnement des électrodes à une distance constante du support souple d'enregistrement indépendamment d'éventuels défauts d'usinage du tambour 4 ou du rouleau 14.Under these conditions there is the same advantage of positioning the electrodes at a constant distance from the flexible recording medium independently of any machining defects in the drum 4 or the
Claims (5)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8205725A FR2524389A1 (en) | 1982-04-02 | 1982-04-02 | ELECTROSTATIC PRINTING HEAD |
FR8205725 | 1982-04-02 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0091073A1 EP0091073A1 (en) | 1983-10-12 |
EP0091073B1 true EP0091073B1 (en) | 1986-05-28 |
Family
ID=9272685
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83103115A Expired EP0091073B1 (en) | 1982-04-02 | 1983-03-29 | Electrostatic printing head |
Country Status (6)
Country | Link |
---|---|
US (1) | US4607269A (en) |
EP (1) | EP0091073B1 (en) |
JP (1) | JPS58187379A (en) |
CA (1) | CA1191189A (en) |
DE (1) | DE3363709D1 (en) |
FR (1) | FR2524389A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2589103B3 (en) * | 1985-10-28 | 1987-10-30 | Telephonie Ind Commerciale | INDIRECT ELECTROSTATIC PRINTER |
US5030975A (en) * | 1988-04-12 | 1991-07-09 | Delphax Systems | Charge transfer imaging cartridge |
US5150134A (en) * | 1991-05-29 | 1992-09-22 | Xerox Corporation | Counter electrode for an electrostatic recorder |
FR2713143B1 (en) * | 1993-12-06 | 1996-01-26 | Dol Christian | Writing head especially for printing machine on electro-sensitive paper. |
AUPN846496A0 (en) * | 1996-03-05 | 1996-03-28 | Research Laboratories Of Australia Pty Ltd | Electronic printing for display technology |
GB2366246A (en) * | 2000-09-01 | 2002-03-06 | Mbna Internat Bank Ltd | Method of electrostatically printing onto a substrate by charging the substrate to form a latent image thereon and developing the image thereafter |
JP2002172813A (en) * | 2000-09-29 | 2002-06-18 | Seiko Epson Corp | Imaging apparatus |
JP2002178554A (en) | 2000-09-29 | 2002-06-26 | Seiko Epson Corp | Imaging unit |
CN2629069Y (en) * | 2002-03-29 | 2004-07-28 | 精工爱普生株式会社 | Writing head and image forming apparatus using the same |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3624661A (en) * | 1969-05-14 | 1971-11-30 | Honeywell Inc | Electrographic printing system with plural staggered electrode rows |
US3771634A (en) * | 1971-05-06 | 1973-11-13 | Bausch & Lomb | Surface pattern stylus board |
DE2125302A1 (en) * | 1971-05-21 | 1972-11-30 | Philips Patentverwaltung | Apparatus for generating charge images in electrostatic electrography |
DE2253625C3 (en) * | 1972-11-02 | 1979-11-08 | Philips Patentverwaltung Gmbh, 2000 Hamburg | Electrode arrangement for electrostatic matrix printing |
FR2394399A1 (en) * | 1977-06-13 | 1979-01-12 | Cit Alcatel | IMAGE PRINT BAR |
US4287525A (en) * | 1977-09-21 | 1981-09-01 | Sharp Kabushiki Kaisha | Multi-pin record electrode assembly and driving method of the same |
FR2456626A1 (en) * | 1979-05-14 | 1980-12-12 | Jaouannet Alain | PRINTING HEAD FOR FIXED HEAD DOT ELECTROSTATIC PRINTER |
JPS57138959A (en) * | 1981-02-23 | 1982-08-27 | Fuji Xerox Co Ltd | Holding mechanism of electrostatic recording head |
-
1982
- 1982-04-02 FR FR8205725A patent/FR2524389A1/en active Granted
-
1983
- 1983-03-29 DE DE8383103115T patent/DE3363709D1/en not_active Expired
- 1983-03-29 EP EP83103115A patent/EP0091073B1/en not_active Expired
- 1983-03-31 CA CA000425046A patent/CA1191189A/en not_active Expired
- 1983-04-01 JP JP58057734A patent/JPS58187379A/en active Granted
-
1985
- 1985-07-25 US US06/758,584 patent/US4607269A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
FR2524389A1 (en) | 1983-10-07 |
CA1191189A (en) | 1985-07-30 |
JPH0343992B2 (en) | 1991-07-04 |
DE3363709D1 (en) | 1986-07-03 |
FR2524389B1 (en) | 1984-05-11 |
EP0091073A1 (en) | 1983-10-12 |
US4607269A (en) | 1986-08-19 |
JPS58187379A (en) | 1983-11-01 |
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