Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
196 words
A device for transferring a powder image from an image support to a receiving material and fixing the powder image theron, comprising a rotatable transfer roller (25) and a first roller (1), a second roller (31), and a third roller (34), which are pressed against the transfer roller (25) with the axes substantially parallel to the axis of rotation of the transfer roller (25), so that a first contact zone (25a), a second contact zone (25b) and a third contact zone (25c) are formed respectively, the first contact zone (25a) being intended for the transfer of the powder image from the image support (1) to the transfer roller (25) and the second contact zone (25b) being intended for transfer of the powder image to the receiving material (19), characterised in that the first contact zone (25a) and the second contact zone (25b) are not situated straight opposite one another on the transfer roller (25) and in that the resultant of the forces by which all the rollers (1, 31 and 34) pressed against the transfer roller (25) are pressed into contact is substantially equal to 0 at the axis of rotation of the transfer roller (25).
Claim 2
Independent Claim
196 words
A device for transferring a powder image from an image support to a receiving material and fixing the powder image theron, comprising a rotatable transfer roller (25) and a first roller (1), a second roller (31), and a third roller (34), which are pressed against the transfer roller (25) with the axes substantially parallel to the axis of rotation of the transfer roller (25), so that a first contact zone (25a), a second contact zone (25b) and a third contact zone (25c) are formed respectively, the first contact zone (25a) being intended for the transfer of the powder image from the image support (1) to the transfer roller (25) and the second contact zone (25b) being intended for transfer of the powder image to the receiving material (19), characterised in that the first contact zone (25a) and the second contact zone (25b) are not situated straight opposite one another on the transfer roller (25) and in that the resultant of the forces by which all the rollers (1, 31 and 34) pressed against the transfer roller (25) are pressed into contact is substantially equal to 0 at the axis of rotation of the transfer roller (25).
Claim 3
Dependent Claim
49 words
A device according to claim 1, characterised in that all the rollers (1, 31 and 34) pressed against the transfer roller (25) are so shaped and pressed against the transfer roller (25) that they form a substantially straight contact zone as considered in the longitudinal direction of the rollers.
Claim 4
Dependent Claim
57 words
A device according to claim 2, characterised in that at least one of the rollers (34) pressed against the transfer roller (25) is cambered and in that the force with which the roller (34) concerned is pressed into contact is exerted on the roller ends, the surface of the roller (34) being straightened in the contact zone.
Claim 5
Dependent Claim
81 words
A device according to claim 2 or 3, characterised in that at least one support roller (32, 33) is provided which presses against the transfer roller (25) one of the rollers (31) pressed against the transfer roller (25)), which support roller (32, 33) is cambered, and in that the force with which the support roller (32, 33) is pressed into contact is exerted at the roller ends, the surface of the support roller (32, 33) being straightened in the contact zone.
Claim 6
Independent Claim
147 words
A device according to any one of the preceding claims, in which the first roller is a photoconductive drum (1) on which a powder image can be formed and the second roller is a pressure roller (31) which presses the receiving material against the transfer roller (25), characterised in that the angle between the radial plane of the transfer roller (25) which extends through the axis of rotation of the drum (1) and the radial plane of the transfer roller (25) which extends through the axis of rotation of the pressure roller (31) is between 130° and 140° and in that the angle between the radial plane of the transfer roller (25) which extends through the axis of rotation of the drum (1) and the radial plane of the transfer roller (25) which extends through the axis of rotation of the third roller (34) is approximately 75°.
Claim 7
Independent Claim
102 words
A device according to any one of the preceding claims, characterised in that the photoconductive drum (1), the pressure roller (31) and the third roller (34) are pressed against the transfer roller (25) by means of springs (39,42,43; 45; 48) and in that a rotatable element (50,51,52) is mounted on the transfer roller (25), which element (50, 51, 52) is provided with individual cams which, on rotation of the element (50, 51, 52) can bring the drum (1), the pressure roller (31) or the third roller (34) respectively out of contact with the transfer roller (25) against the action of the springs.
Claim 8
Dependent Claim
68 words
A device according to claim 6, characterised in that the cams are so formed on the rotatable element (50, 51, 52) that, depending upon the position of the rotatable element (50, 51, 52) only the pressure roller (31), or only the photoconductive drum (1), or both the pressure roller (31), the photoconductive drum (1) and the third roller (34) are out of contact with the transfer roller (25).