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(11) |
EP 0 107 719 B1 |
| (12) |
EUROPEAN PATENT SPECIFICATION |
| (45) |
Mention of the grant of the patent: |
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23.07.1986 Bulletin 1986/30 |
| (22) |
Date of filing: 26.04.1983 |
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International application number: |
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PCT/US8300/613 |
| (87) |
International publication number: |
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WO 8303/798 (10.11.1983 Gazette 1983/26) |
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| (54) |
RIBBON CASSETTE
FARBBANDKASSETTE
CASSETTE A RUBAN
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| (84) |
Designated Contracting States: |
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DE FR GB |
| (30) |
Priority: |
04.05.1982 US 374823
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| (43) |
Date of publication of application: |
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09.05.1984 Bulletin 1984/19 |
| (71) |
Applicant: NCR CORPORATION |
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Dayton, Ohio 45479 (US) |
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| (72) |
Inventors: |
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- SHEEHAN, Bernard, Patrick
Cincinnati, OH 45230 (US)
- WERWICK, Volker
Xenia, OH 45385 (US)
|
| (74) |
Representative: Robinson, Robert George |
|
International Intellectual Property Department,
NCR Limited,
206 Marylebone Road London NW1 6LY London NW1 6LY (GB) |
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| |
|
| Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
|
Technical field
[0001] The invention relates to a ribbon cassette, and, in particular, to a self-regulating
re-inking mechanism included therein.
Background art
[0002] In present day printers, it is common practice to provide and use a ribbon cassette
carrying an endless ribbon which is caused to be driven past a printing station, and
wherein the printing ribbon is either a pre-inked and disposable ribbon or a ribbon
which is to be continuously or frequently re-inked during the printing operation.
The ribbon cassette itself may be of the stuffing-box type wherein the ribbon is contained
within the cassette in random manner and such ribbon is unfolded at the cassette exit
and caused to be driven past the printing station and then guided back into the cassette
to be folded again in random manner therein.
[0003] Additionally, a ribbon may be utilized in a mobius loop configuration within the
cassette wherein the ribbon is in substantially continuous contact with an inking
core or like member, or the ribbon may have a plurality of coils thereof around a
central core for controlled inking or re-inking of the ribbon.
[0004] European Patent Application No. 0,019,649 discloses a ribbon cassette containing
an endless ribbon and having two ink supply rollers for re-inking purposes. Each supply
roller has an associated ink transfer roller pivotally mounted on a lever and urged
by a spring into frictional contact with the respecive ink supply roller. The ink
transfer rollers serve as guides for the ribbon and transfer ink to the ribbon as
it is advanced in contact therewith. A disadvantage of this arrangement is that the
amount of ink transferred to the ribbon is independent of the actual ink requirement
thereof, since the spring loading provides a substantially constant pressure of the
ink transfer rollers on the ink supply rollers and, accordingly, a substantially uniform
ink transfer to the ribbon.
[0005] An arrangement in which the amount of ink transferred to the ribbon depends on the
tension of the ribbon is disclosed in U.K. Patent Application No. 2,033,872. However,
this arrangement uses a separate pressure element to sense ribbon tension for controlling
the contact pressure of an inking wick on the ink transfer roller, and the arrangement,
therefore, adjusts rather slowly to changing tension resulting from changes in ink
condition of the ribbon. Also, the re-inking device including the pressure element
and the wick does not form part of the ribbon cassette but is attachable thereto when
a decline in print impression quality is detected.
[0006] U.S. Patent No. 4,091,914 describes a ribbon cassette having a rotatably mounted
ink supply roll and a transfer roller spaced therefrom and rotatable on an axle having
an abrasive surface. The inner surface of the transfer roller is of a wear-susceptible
material and as it is rotated by the ribbon on the axle, the wear-susceptible material
is gradually worn away, thus increasing the inner diameter of the transfer roller
and causing it to move towards, and eventually engage, the ink supply roll to provide
a delayed and gradual replenishment or ink to the ribbon.
Disclosure of the invention
[0007] It is an object of the present invention to provide a ribbon cassette whose re-inking
mechanism forms an integral part of the cassette and is more sensitive and adjusts
more quickly to changes in ink condition of the ribbon to regulate and automatically
control the amount of ink that is made available and transferred to the ribbon.
[0008] Thus, according to the invention, there is provided a ribbon cassette including an
enclosure, an endless ribbon contained in said enclosure, driving means for moving
the ribbon into and out of said enclosure for use in printing operations, an ink supply
roll rotatably supported . at a fixed location within said enclosure, and an ink transfer
roll rotatably mounted on a carriage which is pivotally mounted within said enclosure,
said transfer roll being rockable to be brought into rotational contact with said
ink supply roll for transferring ink from said ink supply roll to said ribbon, characterized
in that said ink transfer roll is arranged to be moved by the ribbon relative to said
ink supply roll, whereby an increased tension in said ribbon indicating depletion
of ink therein causes increased pressure on said ink supply roll to increase transfer
of ink to said ribbon and whereby a decreased tension in said ribbon indicating a
saturated ink condition in said ribbon causes decreased pressure on said ink supply
roll to decrease transfer of ink to said ribbon.
Brief description of the drawings
[0009] Embodiments of the invention will now be described, by way of example, with reference
to the accompanying drawings, in which:
Fig. 1 is a plan view of a portion of a ribbon cassette according to the invention
illustrating a ribbon re-inking mechanism;
Fig. 2 is a top plan view of the body of a ribbon cassette having the cover removed
to show the interior structure;
Fig. 3 is a front elevational view taken along the line 3-3 of Fig. 2;
Fig. 4 is a side elevational view taken along the line 4-4 of Fig. 2;
Fig. 5 is an enlarged elevational view of a portion of the re-inking mechanism shown
in Fig. 2;
Fig. 6 is a top plan view of the cover of the cassette shown in Fig. 2;
Fig. 7 is a side elevational view taken along the line 7-7 of Fig. 6;
Fig. 8 is a plan view of the underside of the cassette cover shown in Fig. 6; and
Fig. 9 is a side elevational view taken along the line 9-9 of Fig. 8.
Best mode of carrying out the invention
[0010] Fig. 1 shows a portion of a ribbon cassette 10 providing space for a re-inking mechanism
which includes a porous rubber inking roll 12 journaled on a fixed-position shaft
or spindle 32. A transfer roll 18 is rotatably mounted on and carried by a carrier
36 which is journaled on a pivot or spindle 38 and which roll 18 is normally in surface
contact with the inking roll 12. A single guidepost 40 is provided upstream of the
transfer roll 18 to cause the ribbon 20 to travel along a path just short of halfway
around the periphery of the transfer roll 18.
[0011] The pivoting of the transfer roll 18 relative to and into pressure contact with the
inking roll 12 utilizes the ribbon 20 itself to maintain such contact. As the ink
in the ribbon 20 is used or depleted therefrom, the ribbon tension increases by reason
of the drying condition, which increased tension, in turn, causes the ribbon 20 to
urge the transfer roll 18 against the inking roll 12 with a greater force and thereby
cause more or faster transfer of ink from the inking roll 12 to the transfer roll
18. As the transfer roll 18 becomes more saturated with the ink, the ribbon tension
decreases by reason of the ink wetting condition thereof and relieves the urging of
the transfer roll 18 against the inking roll 12 in a manner which regulates the amount
of ink that is transferred from the inking roll 12 to the transfer roll-18. The result
is less re-inking in the case of a saturated ribbon condition and more re-inking as
the ink is depleted from the ribbon 20. In this manner and arrangement, it is seen
that the re-inking mechanism provides for self-regulation and control of the amount
of ink which is transferred from the inking roll 12 to the transfer roll 18 so as
to maintain a properly inked ribbon 20.
[0012] It should be clear that the arrangement of the re-inking mechanism within the ribbon
cassette 10, as specifically shown in Fig. 1, could be of any one of a number of different
forms, depending upon the particular design of the ribbon cassette.
[0013] Fig. 2 is a top plan view of the body of a ribbon cassette having the cover removed
therefrom to show the interior stucture and the various components thereof in a preferred
arrangement of the subject matter of the present invention. Such cassette body 50
is preferably of molded plastic material and takes the shape of a generally rectangular
flat case for supporting the ribbon thereof and which is adapted to fit adjacent or
along the printing station of a printer. As shown, the cassette body 50 includes a
large cavity or chamber 52 formed in part by an outer wall starting at the right side
of the cassette and having a wall portion 54 curving toward the rear of the cassette,
a wall portion 56 running along the rear of the cassette, and a wall portion 58 curving
toward the front of the cassette near the left side thereof. A generally centrally-located
wall 60 extends for a distance through the cassette body 50 and a slanted or inclined
wall 62 is connected with and is directed from one end of the wall 60 at an angle
downwardly and toward the front of the body of the cassette. The wall 62 continues
to form a wall portion 64 along the front of the cassette body and toward the right
side thereof. A short wall portion 66 and another wall portion 68 are located between
the wall portion 64 and the start of the wall portion 54.
[0014] A plurality of latch members or lugs 70 are formed as an integral part of the cassette
body and are positioned generally at the four corners thereof for connection and attachment
to mating receptacles in the cover of the cassette. A front guide or locating finger
72 is provided as an integral part of the cassette body 50 for aid in connecting the
cassette cover with such body. It is understood, of course, that the cassette includes
the body 50 with the cover (later described) connected to form the enclosure for the
ribbon.
[0015] The internal components of the body 50 of the cassette include a pair of rollers
80 and 82 which are positioned to cooperate with each other in driving a ribbon 84
at the entrance end of the cassette, in the direction indicated by the arrow 86, and
into the cavity or chamber 52. It is, of course, to be noted that, while the ribbon
84 is shown as a single strand within the cavity 52, the ribbon is folded many times
in a stuffing manner to substantially fill the cavity. The roller 82 is preferably
the drive roller and is connected to a drive member (not shown) while the idler roller
80 is maintained in a biased position against such roller 82 by means of a spring
88 wrapped around a stud or pin 90 and having one end thereof engageable against one
end of a support arm 92 pivoted on a spindle or a shaft 94. The other end of the spring
88 engages an extension 96 of the wall 62, whereby the arm 92 is thus urged against
the idler roller 80 which, in turn, is urged against the drive roller 82 by action
of the spring 88 to provide a precise drive for the ribbon 84. As is well-known in
the art, the support arm 92 may include a plurality of stripper bearings which are
positioned to mate with and extend between the several ribbon driving portions of
the idler roller 80.
[0016] A ribbon re-inking mechanism is provided and supported within the cassette body 50
adjacent the ribbon 84 exit at the right side thereof. A porous-rubber inking roll
100 is rotatably carried or journaled on a hub 101 supported from a spindle 102 positioned
in a cavity or chamber 104 formed by the walls 60, 62 and 64. An ink transfer roll
110 preferably of plastic material is supported from and carried on a carriage 112
at the right of inking roll 100. The carriage 112 includes a spindle 114 at one end
thereof for rotatably carrying the transfer roll 110 and includes a hub 116 at the
other end thereof seated on a pivot pin or spindle 118. A roller or like bearing 119
is positioned and journaled on a spindle 120 adjacent the wall portion 54. The carriage
112 with the ink transfer roll 110 thereon is journaled or pivoted on the spindle
118 to enable the transfer roll to surface engage with the inking roll 100 in increasing
or decreasing pressure conditions.
[0017] The ribbon 84 is contained within the cavity or chamber 52 in a random or stuffing
manner and is caused to be pulled across a lower ridge or dam 115 and then directed
by a wall portion 122 formed as an end of the wall 60 to take a path around the bearing
119. From such bearing 119, the ribbon 84 is directed around a guidepost 124 and then
around the transfer roll 110 with sufficient tension therein to cause rotation of
the transfer roll along with rotation of the inking roll 100. The spindle 114 provides
a loose fit for ease of rotation of the transfer roll 110. The ribbon 84 is directed
past the exit of the cassette body 50 and along the printing station (not shown) and
then is positioned between the rollers 80 and 82 to be driven thereby and back into
the storage chamber 52. The path of the ribbon is shown along with an indication of
the direction of rotation of the several rollers by means of appropriate arrows in
Fig. 2.
[0018] Figs. 3 and 4 show elevational views of the body 50 of the cassette wherein the front
view (Fig. 3) illustrates a two-degree angle of the ribbon path with respect to the
line of printing for the purpose of making better use of the ribbon width. The cassette
body 50 is formed to provide the entire ribbon path, including that portion of the
ribbon 84 in the storage chamber or cavity 52 as well as the portion past the printing
station, in a plane at two degrees from the line of printing, all as more specifically
described in U.S. Patent No. 4,209,261. The side view in Fig. 4 also shows the latch
members or lugs. 70 along with the spindles or hubs for the several rollers. It should
be noted that the several spindles, pivot pins, and the like are generally molded
as an integral part of the body 50 of the cassette.
[0019] Fig. 5 is an enlarged elevation view of a portion of the re-inking mechanism shown
in Fig. 2 and better illustrates the carriage 112 which has the upstanding hub 116
journaled on the pivot pin 118, the latter shown as being an integral part of the
cassette body 50. The ink transfer roll 110 is freely journaled on the spindle 114
at the other end of the carriage 112 and is caused to be moved in a rockable manner
toward and away from the ink roll 100 (Fig. 2) around the pivot pin 118. It must be
realized, of course, that the extent of the rockable motion is relatively small as
required by the amount of ink on the exterior periphery of the inktransfer roll 110
for re-inking the ribbon 84 and as determined by the tension in the ribbon 84 for
providing the torque for rotating the transfer roll 110 and also the inking roll 100.
[0020] Fig. 6 illustrates the top plan of a cover 130 for the cassette which fits onto the
cassette body 50, shown in Fig. 2. The cover 130 has a ribbed portion 132 covering
approximately the upper half of the cover and which portion generally matches the
outline of the body 50. The ribbed portion 132 provides a design to present a pleasing
appearance across the top of the cover 130 relative to the two-degree angle of the
configuration of the cassette and of the path taken by the ribbon 84. The front portion
134 of the cover is generally plain and provides space for and covers the printing
mechanism which may take the form of print wire solenoids, as more fully described
in U.S. Patent No. 4,209,261. The front portion 134 also includes a tear-off edge
136, and several receptacles 138 are provided in the cover 130 for receiving the lugs
70 (Fig. 2). A recess 140 is provided in the cover 130 for accommodating the ribbon
idler roller 80 while a further recess 142 in the cover accommodates the porous inking
roll 100. As briefly alluded to earlier herein, the cassette includes the body 50
(Fig. 2) with the cover 130 (Fig. 6) fitting thereon to form the enclosure for the
ribbon 84.
[0021] Fig. 7 illustrates the shape of the cassette cover 130 as viewed in the direction
from the right side of Fig. 6. The ribbed portion 132 covers the cassette body 50
and the plain portion 134 extends beyond the body to cover generally the printing
mechanism (not shown) with which the ribbon cassette is associated.
[0022] Fig. 8 shows the underside of the cassette cover 130 in an orientation opposite from
the top plan view thereof in Fig. 6. The underside of the ribbed portion 132 of the
cover 130 also shows the location of an upper ridge or dam 144 for association with
the body 50 carried lower ridge or dam 115, of the inking roll recess 142 and of the
idler roll recess 140 along with the receptacles 138 for receiving the lugs 70 on
the cassette body 50. The frontal portion 134 and the tear-off edge 136 are also shown
in the elevational view in Fig. 9 which is viewed from the right side of Fig. 8.
[0023] In the operation of the ribbon cassette and the re-inking mechanism therein, the
ribbon 84, which is preferably one-quarter inch (6mm) wide and formed in a loop approximately
eighteen feet (5m) long, is loaded or stuffed into the cavity 52 but with a portion
of the loop extending in the path around the roller 119 and around the ink transfer
roll 110, along the printing station or line of printing generally in the vicinity
of the tear-off edge 136, and then between the idler and drive rollers 80 and 82,
which preferably drive the ribbon in continuous manner, and back into the chamber
52.
[0024] As the ribbon 84 is being subjected to impact by the printing elements (such as print
wires) during the printing operation, the ink in the ribbon is being used or consumed
in such operation. As ink is depleted from the ribbon 84, the ribbon is less saturated,
or may become dry in a relative sense, and the frictional force between the less saturated
ribbon and the ink transfer roll 110 increases along with a corresponding increase
in ribbon tension resulting from the pull of the idler and drive rollers 80 and 82
and the increased frictional force. The increased ribbon tension, in turn, causes
the ribbon 84 to increase the pressure on or against the ink transfer roll 110 and
to push or ease such roll in rockable manner against and in surface contact with the
inking roll 100 with a greater force to effect an increased transfer of ink to the
transfer roll and therefrom to the ribbon.
[0025] As the ribbon 84 becomes more saturated with an increased transfer of ink thereto,
the ribbon tension decreases in relative terms by reason of the ink saturated or wet
condition since, in effect, such ribbon does not have as much frictional force in
rotating the ink transfer roll 110. The effect of decreased ribbon tension and decreased
frictional force reduces the amount or rate of ink transfer from the inking roll 100
to the transfer roll 110 by reason of the transfer roll 110 rocking or easing away
from the inking roll 100. It is seen that a lesser amount of ink is transferred or
lesser re-inking is necessary when the ribbon is relatively saturated and that a greater
amount of ink is transferred or more re-inking is required when ink becomes depleted
from the ribbon or when the ribbon is relatively less saturated. In this manner of
operation, the re-inking process is self-regulating and, in effect, automatically
re-inks the ribbon, dependent upon the ink saturated condition thereof.
[0026] It is thus seen that herein shown and described is a ribbon cassette having a re-inking
mechanism therein which utilizes increased and decreased tension in the ribbon itself
to effect an increase and a decrease in the pressure of an ink transfer roll bearing
against an inking roll in the manner of rocking motion of the ink transfer roll relative
to the stationary inking roll.
1. A ribbon cassette including an enclosure (50), an endless ribbon (20, 84) contained
in said enclosure (50), driving means (80, 82) for movin.g the ribbon (20, 84) into
and out of said enclosure (50) for use in printing operations, an ink supply roll
(12, 100) rotatably supported at a fixed location within said enclosure (50), and
an ink transfer roll (18, 110) rotatably mounted on a carriage (36, 112) which is
pivotally mounted within said enclosure (50), said transfer roll (18, 110) being rockable
to be brought into rotational contact with said ink supply roll (12, 100) for transferring
ink from said ink supply roll (12, 100) to said ribbon (20, 84), characterized in
that said ink transfer roll (18, 110) is arranged to be moved by the ribbon (20, 84)
relative to said ink supply roll (12, 100), whereby an increased tension in said ribbon
(20, 84) indicating depletion of ink therein causes increased pressure on said ink
supply roll (12, 100) to increase transfer of ink to said ribbon (20, 84) and whereby
a decreased' tension in said ribbon (20, 84) indicating a saturated ink condition
in said ribbon (20, 84) causes decreased pressure on said ink supply roll (12, 100)
to decrease transfer of ink to said ribbon (20, 84).
2. A ribbon cassette according to claim 1, characterized by guide means (40, 124)
for directing the ribbon (20, 84) in a path to provide sufficient frictional contact
with said ink transfer roll (18, 110) for rotational driving thereof and for movement
thereof relative to said ink supply roll (12, 100).
3. A ribbon cassette according to claim 2, characterized in that said guide means
is a guide post (40, 124) arranged to direct the ribbon (20, 84) in a path approximately
halfway around the periphery of said ink transfer roll (18, 110).
4. A ribbon cassette according to claim 1, characterized in that said ink transfer
roll (18, 110) is freely journaled on a spindle (114) positioned at one end of said
carriage (112), whose other end is mounted on a pivot pin (118) integrally formed
with a wall of said enclosure (50).
5. A ribbon cassette according to claim 4, characterized in that said carriage (112)
has at its said other end an upstanding hub (116) journaled on said pivot pin (118).
6. A ribbon cassette according to claim 1, characterized in that said ink supply roll
(12, 100) is rotatably mounted on a spindle (102) integrally formed with a wall of
said enclosure (50).
7. A ribbon cassette according to claim 1, characterized in that said ink supply roll
(12, 100) is made of porous rubber.
8. A ribbon cassette according to claim 1, characterized by a chamber (52) within
said enclosure (50) for containing said ribbon (84) in random manner.
1. Bandkassette mit einem Gehäuse (50), einem endlosen Band (20, 84), das in dem Gehäuse
(50) enthalten ist, Antriebsvorrichtungen (80, 82) zum Bewegen des Bandes (20, 84)
in das und aus dem Gehäuse (50) zur Verwendung in Druckvorgängen, einer Farbabgabewalze
(12, 100), die an einer ortsfesten Position innerhalb des Gehäuses (50) drehbar abgestützt
ist, und einer FarbübertragungswaIze (18, 110), die drehbar an einem Wagen (36, 112)
angebracht ist, der schwenkbar innerhalb des Gehäuses (50) angeordnet ist, wobei die
Farbeübertragungswalze (18, 110) schwenkbar ist für einen Rotationskontakt mit der
Farbabgabewalze (12, 100) zum Übertragen von Farbe von der Farbabgabewalze (12, 100)
zu dem Band (20, 84) angebracht ist, dadurch gekennzeichnet, daß die Farbübertragungswalze
(18, 110) angeordnet ist, um durch das Band (20, 84) relativ zur Farbabgabewalze (12,
100) bewegt zu werden, wobei eine erhöhte Spannung in dem Band (20, 84), die eine
Erschöpfung der Farbe darin anzeigt, einen erhöhten Druck auf die Farbabgabewalze
(12, 100) bewirkt, um die Übertragung von Farbe vom Band (20, 84) zu erhöhen, und
wobei eine verringerte Spannung in dem Band (20, 84), die einen gesättigten Farbzustand
in dem Band (20, 84) anzeigt, einen verringerten Druck auf die Farbabgabewalze (12,
100) bewirkt, um die Übertragung von Farbe zum Band (20, 84) zu verringern.
2. Bandkassette nach Anspruch 1, gekennzeichnet durch Führungsvorrichtungen (40, 124)
zum Führen des Bandes (20, 84) auf einem Weg, um einen ausreichenden Reibungskontakt
mit der Farbübertragungswalze (18, 110) für einen Rotationsantrieb derselben und für
eine Bewegung derselben relativ zur Farbabgabewalze (12, 100) zu bieten.
3. Bandkassette nach Anspruch 2, dadurch gekennzeichnet, daß die Führungsvorrichtungen
aus einem Führungsbolzen (40, 124) bestehen, der dazu angeordnet ist, das Band (20,
84) in einem Pfad annähernd halb um den Umfang der Farbübertragungswalze (18, 110)
zu führen.
4. Bandkassette nach Anspruch 1, dadurch gekennzeichnet, daß die Farbübertragungswalze
(18, 110) frei beweglich auf einer Spindel (114) angeordnet ist, die an einem Ende
des Wagens (112) angebracht ist, dessen anderes Ende auf einem Schwenkstift (118)
befestigt ist, der einstückig mit einer Wand des Gehäuses (50) gebildet ist.
5. Bandkassette nach Anspruch 4, dadurch gekennzeichnet, daß der Wagen (112) an seinem
anderen Ende eine. nach oben stehende Nabe (116) aufweist, die auf dem Schwenkstift
(118) angebracht ist.
6. Bandkassette nach Anspruch 1, dadurch gekennzeichnet, daß die Farbabgabewalze (12,
100) drehbar auf einer Spindel (102) angebracht ist, die einstückig mit einer Wand
des Gehäuses (50) gebildet ist.
7. Bandkassette nach Anspruch 1, dadurch gekennzeichnet, daß die Farbabgabewalze (12,
100) aus porösem Gummi besteht.
8. Bandkassette nach Anspruch 1, gekennzeichnet durch eine Kammer (52) innerhalb des
Gehäuses (50) zum Aufnehmen des Bandes (84) in beliebiger Weise.
1. Cassette de ruban comprenant un boîtier (50), un ruban sans fin (20, 84) logé dans
ledit boîtier (50), des moyens d'entraînement (80, 82) destinés à déplacer le ruban
(20, 24) afin de le faire pénétrer dans et sortir dudit boîtier (50) pour l'utiliser
à des opérations d'impression, un rouleau encreur (12, 100) monté de façon à pouvoir
tourner dans une position fixe à l'intérieur dudit boîtier (50), et un rouleau (18,
110) de transfert d'encre monté sur un chariot (112) de façon à pouvoir tourner, ledit
chariot étant monté de facon à pouvoir pivoter à l'intérieur dudit boîtier (50), ledit
ruban (18, 110), de transfer d'encre étant monté de façon à tourner en contact avec
ledit rouleau encreur (12, 100) pour transférer de l'encre dudit rouleau encreur (12,
100) vers ledit ruban (20, 84), caractérisée en ce que ledit rouleau (18, 110) de
transfert d'encre est agencé de façon à être déplacé par le ruban (20, 84) par rapport
audit rouleau encreur (12, 100) afin qu'une tension accrue appliquée audit ruban (20,
84), indiquant l'épuisement de l'encre de ce dernier, provoque un accroissement de
la pression exercée sur ledit rouleau encreur (12, 100) pour augmenter le transfert
d'encre vers ledit ruban (20, 84) et qu'une diminution de la tension appliquée audit
ruban (20, 84), indiquant une condition de saturation en encre dudit ruban (20, 84),
provoque une diminution de la pression exercée sur ledit rouleau encreur (12, 100)
afin de faire diminuer le transfert d'encre vers ledit ruban (20, 84).
2. Cassette de ruban selon la revendication 1, caractérisée par des moyens de guidage
(40, 124) destinés à diriger le ruban (20, 84) suivant un trajet pour établir un contact
de frottement suffisant avec ledit rouleau (18, 110) de transfert d'encre pour l'entraîner
en rotation et le déplacer par rapport audit rouleau encreur (12, 100).
3. Cassette de ruban selon la revendication 2, caractérisée en ce que lesdits moyens
de guidage comprennent une colonnette (40,124) de guidage disposée de façon à diriger
le ruban (20, 84) suivant un trajet contournant approximativement la moitié de la
périphérie dudit rouleau (18, 110) de transfert de l'encre.
4. Cassette de ruban selon la revendication 1, caractérisée en ce que ledit rouleau
(18, 110) de transfert d'encre tourillonne librement sur un axe (114) placé à une
extrémité dudit chariot (112) dont l'autre extrémité est montée sur un axe (118) de
pivotement réalisé d'une seule pièce avec une paroi dudit boîtier (50).
5. Cassette de ruban selon la revendication 4, caractérisée en ce que ledit chariot
(112) comporte, à son autre extrémité, un moyeu (116) orienté vers le haut et tourillonnant
sur ledit axe (118) de pivotement.
6. Cassette de ruban selon la revendication 1, caractérisée en ce que ledit rouleau
encreur (12, 100) est monté de façon à pouvoir tourner sur un axe (102) réalisé d'une
seule pièce avec une paroi dudit boîtier (50).
7. Cassette de ruban selon la revendication 1, caractérisée en ce que ledit rouleau
encreur (12, 100) est réalisé en caoutchouc poreux.
8. Cassette de ruban selon la revendication 1, caractérisée par une chambre (52) située
à l'intérieur dudit boîtier (50) et destinée à contenir ledit ruban (84) d'une manière
désordonnée.