EP0060030A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Electrophotographic copier
Assignee: Olivetti SpA
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Filing: 1982-02-10
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Granted: —
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Expires: 2002-02-10
Abstract
Abstract The photocopier uses a development process employing a magnetic brush formed on a rotating sleeve (102) of non-magnetic material in which a system of permanent magnets (108) rotates. The outer surface of the sleeve is subjected to a sandblasting process after grinding in order to create a very uniform finely roughened surface in order to make the thickness of the toner layer forming the magnetic brush constant. The photocopier also employs a toner fixing system operating cold and under pressure by means of a pair of rollers (56, 58) of different diameter rotating at the same angular speed in order to create slippage of the upper roller relative to the lower roller for the purpose of obtaining perfectly flat copies. The coppier also contains a single circuit board (80) for the low voltage and high voltage supply.
Inventors
- 👤 Bruno Cestari
- 👤 Riccardo Forlani
- 👤 Piero Gontero
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 00:50
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/80; G03G15/06; G03G15/08; G03G15/09; G03G15/0921; G03G15/0928
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
85 words
Electrophotographic copier comprising a photoconductor element arranged to form a latent image of an original to be reproduced, and a magnetic brush with a rotatable sleeve of non-magnetic material for developing said latent image, characterised in that sleeve (1021 has a rough external surface, the roughness lying between 0.3 and 2 pm RA, so that during the development process, the excess toner particles encounter the microprotuberances of the rough surface in a random manner and remain distributed along the sleeve in an averagely uniform manner.
Claim 2
Dependent Claim
85 words
Electrophotographic copier comprising a photoconductor element arranged to form a latent image of an original to be reproduced, and a magnetic brush with a rotatable sleeve of non-magnetic material for developing said latent image, characterised in that sleeve (1021 has a rough external surface, the roughness lying between 0.3 and 2 pm RA, so that during the development process, the excess toner particles encounter the microprotuberances of the rough surface in a random manner and remain distributed along the sleeve in an averagely uniform manner.
Claim 3
Dependent Claim
23 words
Copier as claimed in claim 1, characterised in that the rough surface is obtained by a grinding operation followed by a sandblasting operation.
Claim 4
Dependent Claim
29 words
Copier as claimed in claim 2, characterised in that the sandblasting operation is carried out with abrasive powder having a particle size between the standard values 60 and 400.
Claim 5
Dependent Claim
47 words
Copier as claimed in one of the preceding claims in which the magnetic brush comprises a plurality of axial magnets rotating inside the sleeve, characterised by a pair of rings (110) of ferromagnetic material fixed coaxially to the sleeve (102) at the ends of the magnets (108).
Claim 6
Dependent Claim
45 words
Copier as claimed in any of the preceding claims, further comprising a slot for feeding a development powder to the magnetic brush and extending along the sleeve, characterised in that the length of the slot (105) is less than the length of the sleeve (102).
Claim 7
Dependent Claim
26 words
Copier as claimed in claim 5, characterised in that the slot (105) has a length from 80 to 92% of the length of the sleeve (102).
Claim 8
Dependent Claim
119 words
Electrophotographic copper comprising means for developing a latent image of an original to be reproduced and formed on a photoconductor element, means for transferring the developed image on to a sheet of paper, and a pair of opposing rollers for the cold-fixing of the image transferred on to said sheet, by the action of the pressure between the rollers, and in which the rollers have their axes inclined to each other and at least one roller as a rough surface, characterised in that the roller (58) with the rough surface has a peripheral speed greater than the opposing roller (56) of the pair, so that any deformation of the sheet caused by the inclination of the rollers is nullified.
Claim 9
Dependent Claim
119 words
Electrophotographic copper comprising means for developing a latent image of an original to be reproduced and formed on a photoconductor element, means for transferring the developed image on to a sheet of paper, and a pair of opposing rollers for the cold-fixing of the image transferred on to said sheet, by the action of the pressure between the rollers, and in which the rollers have their axes inclined to each other and at least one roller as a rough surface, characterised in that the roller (58) with the rough surface has a peripheral speed greater than the opposing roller (56) of the pair, so that any deformation of the sheet caused by the inclination of the rollers is nullified.
Claim 10
Dependent Claim
36 words
Copier as claimed in claim 7, characterised in that the rollers (56, 58) rotate at the same angular speed in opposite directions and the rough roller (58) has a greater diameter than the opposing roller (56).
Claim 11
Dependent Claim
30 words
Copier as claimed in claim 6 or 7, characterised in that the rough roller (58) slips on the opposing roller (56) with a slippage ratio of between 0.001 and 0.003.
Claim 12
Dependent Claim
73 words
Copier as claimed in any of claims 7 to 9, characterised in that the said opposing roller (56) is lubricated with silicone oil by means of a lubricating element formed from a sprongy member (160) enclosed within a fabric (162) provided with pile fibres (168) on its outer face, so that the oil is transferred, by contact, to the rough roller (58) in order to prevent toner particles adhering to the surface thereof.
Claim 13
Dependent Claim
29 words
Copier as claimed in claim 10, characterised in that the fabric (162) is a velvet having a layer of pile fibres of length from 1 mm to 10 mm.
Claim 14
Dependent Claim
157 words
Electrophotographic copier for reproducing an original on a sheet of paper, comprising means for polarising a photoconductor element by means of a first high voltage, means for developing a latent image of the original formed on the photoconductor, means for transferring the developed image on to the sheet by means of a second high voltage, means for nullifying the polarisation which are fed by an alternating voltage, and a low voltage power unit for feeding the copier, characterised in that a single printed circuit board (80) contains both the low voltage power unit (81) and a generator (82, 86) for the first and second high voltage and for the alternating voltage, the high voltage generator being embedded in a resin having a dielectric constant of at least 15 KV/mm and a resistivity of at least 10 14 ohm. cm, so that any possible discharge of the high voltage on to the circuits of the board is prevented.
Claim 15
Dependent Claim
157 words
Electrophotographic copier for reproducing an original on a sheet of paper, comprising means for polarising a photoconductor element by means of a first high voltage, means for developing a latent image of the original formed on the photoconductor, means for transferring the developed image on to the sheet by means of a second high voltage, means for nullifying the polarisation which are fed by an alternating voltage, and a low voltage power unit for feeding the copier, characterised in that a single printed circuit board (80) contains both the low voltage power unit (81) and a generator (82, 86) for the first and second high voltage and for the alternating voltage, the high voltage generator being embedded in a resin having a dielectric constant of at least 15 KV/mm and a resistivity of at least 10 14 ohm. cm, so that any possible discharge of the high voltage on to the circuits of the board is prevented.
Claim 16
Dependent Claim
171 words
Electrophotographic copier for reproducing by means of a magnetic toner a latent image formed on a rotatable drum, comprising a sleeve rotatable in the opposite direction to the drum and containing a rotatable magnetic roller, the sleeve being arranged to feed the toner to the drum in the same direction as the direction of rotation of the drum, and a hopper for the toner comprising a first edge for forming an accumulation of toner against the outer face of the first edge, and a second edge for controlling the height of the toner on the sleeve, characterised in that the first edge (134) is set back from the second edge (124) by a distance (b) of between 0.5 and 1 mm, and the second edge (124) is spaced from the sleeve α02) by a distance (a) of between 0.4 and 0.5 mm, so that the accumulation prevents and permits the flow of toner from the hopper (104) when it respectively extends beyond and does not extend beyond the first edge (134).
Claim 17
Dependent Claim
171 words
Electrophotographic copier for reproducing by means of a magnetic toner a latent image formed on a rotatable drum, comprising a sleeve rotatable in the opposite direction to the drum and containing a rotatable magnetic roller, the sleeve being arranged to feed the toner to the drum in the same direction as the direction of rotation of the drum, and a hopper for the toner comprising a first edge for forming an accumulation of toner against the outer face of the first edge, and a second edge for controlling the height of the toner on the sleeve, characterised in that the first edge (134) is set back from the second edge (124) by a distance (b) of between 0.5 and 1 mm, and the second edge (124) is spaced from the sleeve α02) by a distance (a) of between 0.4 and 0.5 mm, so that the accumulation prevents and permits the flow of toner from the hopper (104) when it respectively extends beyond and does not extend beyond the first edge (134).
References Cited (Backward Citations)
No citation records indexed.
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