EP0506351B1

EP0506351B1 - Printer and ink ribbon cartridge for printer

Info

Publication number: EP0506351B1
Application number: EP92302549A
Authority: EP
Inventors: Jukka Hyvärinen
Original assignee: ICL Personal Systems Oy
Current assignee: ICL Personal Systems Oy
Priority date: 1991-03-25
Filing date: 1992-03-25
Publication date: 1996-07-31
Anticipated expiration: 2012-03-25
Also published as: FI92987B; FI911429A; FI92987C; ATE140899T1; EP0506351A1; DE69212517D1; FI911429A0

Abstract

The invention relates to a printer, comprising a print head; a paper path for a document to be printed; and an ink ribbon cartridge (3) with a drive motor (7) and transmission means (8 to 14) belonging thereto. A drive mechanism comprises a pair of drive wheels, which wheels (4, 5) form a 90 DEG angle with each other, the axle of the first wheel (4) being perpendicular to the level formed by the cartridge (3) and the axle of the second wheel (5) being parallel with the level formed by the cartridge; and a straight drive shaft (6) positioned between the second wheel (5) and the transmission means. The invention also relates to an ink ribbon cartridge (3), comprising drive wheels (4, 5) arranged in the manner described above. <IMAGE>

Description

The invention relates to a printer, comprising a print head; a paper path for a document to be printed; and an ink ribbon cartridge with a drive motor and transmission means belonging thereto. The invention additionally relates to an ink ribbon cartridge for a printer, which cartridge comprises a frame, an ink ribbon and a drive wheel for driving the ink ribbon, which drive wheel is positioned in such a way that its axle is perpendicular to the horizontal surface of the frame.
EP-A-0337527 discloses an ink ribbon cartridge with a drive mechanism comprising a pair of drive wheels in driving connection with each other, wherein the wheels form a 90° angle with each other, the axle of the first wheel being perpendicular to the horizontal surface of the cartridge and the axle of the second wheel being parallel with the horizontal surface of the cartridge.
A couple of mounting movements in different directions were previously needed for locking an ink ribbon cartridge or the mounting required an additional curved mounting movement. To change the ink ribbon cartridge, it was necessary to open different kinds of lock mechanisms. Moreover, different kinds of guide pins were needed for mounting a cartridge, by which pins the cartridge could be positioned accurately in the right place. All the facts mentioned above have made a change of ink ribbon cartridge into a measure requiring accuracy, and it has not always been possible to avoid ink-stained fingers.
The object of the present invention is to eliminate the problems described above by means of a novel printer and ink ribbon cartridge. This object is achieved by means of a printer of the invention, which is characterised in the features presented in claim 1; and by means of an ink ribbon cartridge of the invention, which is characterised in the properties presented in claim 7.
The invention is based on an idea to use a pair of coupled drive wheels in connection with an ink ribbon cartridge, which wheels form a 90° angle with each other, whereby the drive from the printer to the ink ribbon cartridge can be arranged by means of a straight drive shaft parallel with the cartridge surface. Only one movement in one direction is then needed for changing the cartridge and for coupling the drive shaft.
The pair of drive wheels serves as a reduction gear, and so the transmission between the drive motor and the drive shaft does not need to transmit any big torque. Due to this the drive wheels and the drive shaft can preferably be manufactured of plastic without losing their reliability.
For securing the cartridge in place, no separate lock mechanisms are needed, because the torque caused by the drive shaft does not try to move the cartridge in the unmounting direction. Consequently, no separate lock devices are required for the cartridge and it is not necessary to touch the ink ribbon by hand.
Each drive wheel is changed at each change of cartridge, though they would last a considerably longer time. The reliability of operation is thus guaranteed.
An advantage of the invention is also that the manufacture, assembly and mounting of the cartridge, i.e. the tolerances, do not influence the drive mechanism in a disadvantageous manner.
Below the invention is described by means of an embodiment given by way of example only and referring to the enclosed drawings, in which

Figure 1 shows a simplified general view of a printer and an ink ribbon cartridge,
Figure 2 the ink ribbon cartridge,
Figure 3 drive wheels of the ink ribbon cartridge on an enlarged scale, and
Figure 4 the arrangement of the ink ribbon cartridge in the printer.

Figures 1 and 4 show a printer according to the invention, comprising a print head 1, a paper path 2 for a document to be printed and an ink ribbon cartridge 3 with a drive mechanism 4, 5, 6, a drive motor 7 and transmission means 8 to 14 belonging thereto. Figure 4 relates to an area X of Figure 1 and shows the arrangement of the cartridge 3 in the printer in the direction of arrow A, obliquely from below. Figure 1 shows the printer simplified and not all the details thereof are shown. Additionally, Figure 1 shows the ink ribbon cartridge 3 separately from the printer.
The drive mechanism of the ink ribbon cartridge 3 comprises a pair of drive wheels, which wheels 4 and 5 form a 90° angle with each other. The axle of the first wheel 4 is perpendicular to the level or major surface formed by the cartridge 3 and the axle of the second wheel 5 is parallel with the level formed by the cartridge 3. The drive mechanism comprises further a straight drive shaft 6 positioned between the second wheel 5 and the transmission means 8 to 14. Both drive wheels 4 and 5 are mounted to fixed positions in a frame 3a of the cartridge 3 (see especially Figures 2 and 3). The drive wheels 4 and 5 can be for instance gear wheels, friction wheels or pin wheels. The drive shaft 6 can be a separate part or it can form an integral whole with the second drive pulley 5. Figure 4 may concern both cases, because structures like this do not necessarily differ from each other, as far as appearance is concerned, when the cartridge 3 is fastened to the printer.
The ink ribbon cartridge 3 of the invention is substantially similar to the prior art ink ribbon cartridges, except for the drive mechanism described above, and includes an ink ribbon 3b, which is folded within the frame 3a in a conventional manner and with which the first drive wheel 4 is in driving contact.
According to the present invention, it is extremely simple to mount the ink ribbon cartridge 3 in the printer. The cartridge 3 is pushed into guide track 15 of the printer by means of one horizontal movement (arrow B in Figure 1) and the drive shaft 6 is simultaneously coupled between the transmission means 8 to 14 and the second drive wheel 5 of the cartridge 3. Because the drive shaft 6 usually is ready-fastened to the transmission means or fastened to the cartridge 3, no problems are caused by coupling the drive shaft either.
The drawings and the specification related thereto are only intended to visualize the idea of the invention. One skilled in the art can vary the details of the printer and the ink ribbon cartridge of the invention in many different ways within the scope of the enclosed claims. Thus, a possible alternative in connection with the printer of the invention is that the second drive wheel of the drive mechanism of the ink ribbon cartridge is fastened to the drive shaft, which is made loose, in which case the ink ribbon cartridge comprises only the first drive wheel.

Claims

A printer, comprising a print head (1); a paper path (2) for a document to be printed; an ink ribbon cartridge (3) with a drive mechanism (4, 5, 6), and a drive motor (7) and transmission means (8 to 14) belonging thereto, wherein the drive mechanism of the ink ribbon cartridge (3) comprises a pair of drive wheels (4,5) in driving connection with each other, wherein said wheels (4, 5) form a 90° angle with each other, the axle of the first wheel (4) being perpendicular to the horizontal surface of the cartridge (3) and the axle of the second wheel (5) being parallel with the horizontal surface of the cartridge (3), characterised in that the printer further comprises a straight drive shaft (6) directly connected between the second wheel (5) and the transmission means (8 to 14), whereby the cartridge (3) may be inserted into the printer horizontally to drivingly connect said transmission means (8 to 14), said straight drive shaft (6) and said drive wheels (4, 5).
A printer according to claim 1, characterised in that the drive wheels (4, 5) are gear wheels.
A printer according to claim 1, characterised in that the drive wheels (4, 5) are friction wheels.
A printer according to claim 1, characterised in that the drive wheels (4, 5) are pin wheels.
A printer according to one of the foregoing claims, characterised in that both drive wheels (4, 5) are mounted in fixed positions in a frame (3a) of the cartridge.
A printer according to one of the foregoing claims, characterised in that the drive shaft (6) forms an integral whole with the second drive wheel (5).
An ink ribbon cartridge for a printer, which cartridge (3) comprises a frame (3a), an ink ribbon (3b) and a drive wheel (4) for driving the ink ribbon, which drive wheel is positioned at one end of the frame (3a) in such a way that its axle is perpendicular to the horizontal surface of the frame, wherein in driving connection with said drive wheel (4) is arranged a second drive wheel (5), the axle of which forms a 90° angle with the axle of the first drive wheel, characterised in that said second drive wheel (5) is adapted to be coupled to a straight drive shaft (6), said drive shaft (6) being co-axial with said second drive wheel (5) and being adapted to be directly connected to transmission means (8 to 14) belonging to a drive motor (7) of said printer whereby said cartridge (3) may be inserted horizontally into said printer to drivingly connect said transmission means (8 to 14), said straight drive shaft (6) and said drive wheels (4, 5).
An ink ribbon cartridge according to claim 7, characterised in that said straight drive shaft (6) forms an integral whole with said second drive wheel (5), one end of said drive shaft being adapted for connecting to the transmission means (8 to 14) belonging to the drive motor (7) of said printer.
An ink ribbon cartridge according to claim 7 or 8, characterised in that the drive wheels (4, 5) are gear wheels.
An ink ribbon cartridge according to claim 7 or 8, characterised in that the drive wheels (4, 5) are friction wheels.
An ink ribbon cartridge according to claim 7 or 8, characterised in that the drive wheels (4, 5) are pin wheels.