Tape printer having a cutter with a guide mechanism

Abstract: The invention refers to a tape cassette (10) that accomodates a printable tape (14) and can be inserted into a tape printing device, said tape cassette (10) comprises a housing having a wall portion (22) which is arranged to support the tape (14) during a cutting operation performed with a cutting mechanism of said tape printing device. In order to align the cutting mechanism with the cassette during cutting, it is proposed that the wall portion (22) is arranged for interacting with a guide mechanism which connects the cutting mechanism and said wall portion (22) during cutting such that the cutting mechanism is aligned with respect to the wall portion (22).

Description: The present invention relates to a cassette for a tape printer, and to a printer for use with such a cassette, and in particular to the cutting mechanism. Known tape printing apparatus of the type with which the present invention is generally concerned are disclosed in EP-A-0 322 918 and EP-A-0 322 919 (Brother KK) and EP-A-0 267 890 (Varitronic). The printers each include a printing device having a cassette receiving bay for receiving a cassette or tape holding case. In EP-A-0 322 918, the tape holding case houses an ink ribbon, a transparent image receiving tape and a double-sided adhesive tape which is secured at one of its adhesive coated sides to the image tape after printing and which has a backing paper peelable from its other adhesive side. With both these apparatus, the image transfer medium (ink ribbon) and an image receiving tape (substrate) are in the same cassette. The present applicants have developed a different type of tape printing apparatus which is described for example in EP-A-0 578 372. In this printing apparatus, the substrate tape is similar to that described in EP-A-0 267 890 but is housed in its own tape holding case while the ink ribbon is similarly housed in its own tape holding case. In all of these cases, the image receiving tape passes in overlap with the ink ribbon to a print zone consisting of a fixed print head and a platen against which the print head can be pressed to cause an image to transfer from the ink ribbon to the image receiving tape. There are many ways doing this, including dry lettering or dry film impression, but the most usual way at present is by thermal printing where the print head is heated and the heat causes ink from the ink ribbon to be transferred to the ink receiving tape. Alternatively, the print head may be in direct contact with a thermally sensitive image receiving tape whereby when the print head is heated, an image is defined on the image receiving tape. When the desired image has been printed onto the image receiving tape, the user needs to cut off the printed portion of tape from the supply in order to use it as a label. Thus, different cutting mechanisms are known in the art. They comprise scissors (EP-A-0 267 890, EP-A-0 327 075, DE-A-4 410 931), blades acting against an anvil (EP-A-0 364 305, EP-A-0 450 779, EP-A-0 719 620), and cooperating cutting blades (EP-A-0 636 562, EP-A-0 734 818). Further, in EP-A-0 634 275 a guillotine cutter is described which protrudes during the cutting operation into a slot of the tape cassette, while the walls of the cassette besides the slot support the tape. In this arrangement, it is necessary to manufacture the cutting mechanism and the cassette within small tolerances, in order to achieve that the cutting blade indeed travels into the cutting slot, and does not contact the side walls of the slot or even the portion of the wall of the cassette which supports the tape during cutting. Small tolerances are further required to obtain a cut having an angle of exactly 90° with respect to the longitudinal axis of the tape. A disadvantage of the prior art is thus the necessity to have such small tolerances, what increases the productions costs. It is an object of the present invention to provide a tape cutting mechanism which is insensitive to mechanical tolerances both of the cutting apparatus and of the tape cassette. According to a first aspect of the invention, there is provided a tape cassette that accomodates a printable tape and is suitable for being detachably received in a tape printing device having a tape cassette receiving member therein, said tape cassette comprising a housing having a wall portion which is arranged to support the tape during a cutting operation performed with a cutting mechanism of said tape printing device, characterized in that a guideway is provided within said wall portion of said cassette, said guideway having the form of a hole or a channel, wherein the guideway is arranged for accomodating a pin connected to the cutting mechanism. The invention proposes to connect the portion of the wall of the tape cassette against which the cutting mechanism acts with the cutting mechanism. This connection is present at least during the cutting operation, and is advantageously released when the user intends to withdraw the cassette from the tape printing device. The connection provides a guidance for the cutting mechanism with respect to the tape cassette, such that the cutting zone is at the appropriate location. The cut through the tape will thus be at the desired place, and extend generally orthogonally to the feed direction of the tape. Within the scope of the invention it is possible that the guide mechanism aligns the cutting mechanism with respect to the tape cassette (what is the preferred embodiment, since it allows the cassette to be fixed with respect to the printing mechanism of the tape printer, hence yielding the best possible printing quality), but it would also be thinkable to let the guidance align the tape cassette with respect to said cutting mechanism. The guide mechanism comprises a pin fixed to the cutting mechanism which is arranged to protrude into the guideway of the tape cassette during cutting. The guideway can have the form of a hole or a channel. Preferably, the pin and/or the guideway have a rectangular rather than a round section in order to maximise the stiffness and simplify moulding. According to a second aspect of the invention, there is provided a tape cassette that accomodates a printable tape and is suitable for being detachably received in a tape printing device having a tape cassette receiving member therein, said tape cassette comprising a housing having a wall portion which is arranged to support the tape during a cutting operation performed with a cutting mechanism of said tape printing device, characterized in that said wall portion is arranged for interacting with a guide mechanism which connects the cutting mechanism and said wall portion during cutting such that the cutting mechanism is aligned with respect to said wall portion. The guideway is advantageously provided within said wall portion of said cassette. Then, the pin is connected to the cutting mechanism. It would as well be possible to have the guideway mounted to the cutting mechanism, and the pin fixed to the wall of the cassette. A part of the wall portion is provided, which is arranged such that the tape is supported on said part of said wall portion during cutting. The cutting mechanism can cut against the wall of the cassette which is acting as an anvil, as disclosed in EP-A-0 364 305. In another embodiment, a slot on the wall portion of the tape cassette may be provided, which is arranged such that a blade of said cutting mechanism can travel into the slot during cutting. This avoids the need of an anvil for cutting. It has been found that the cutting force required is significantly reduced, as is the wear of the blade. Further, the guideway and the pin may be provided in the vicinity of the end or ends of a blade of said cutting mechanism. The pin is thus located at the end of the blade, such that it does not interfere with the tape during cutting. It should be mentioned that it is preferred to have two pins and guideways, located at opposite sides of the tape, and hence situated at both ends of the cutting blade. In order to "catch" the pin with the guideway, even when the tape cassette is not exactly aligned with respect to the cutting mechanism, it is proposed that the guideway has a generally conical shape, with the larger diameter facing towards the pin. Thus, the free diameter of the guideway, which is in the form of a channel or a deep boring, gets narrower the deeper the pin protrudes. Thus, an exact alignment of the cutting mechanism towards the tape cassette is obtained. Alternatively or additionally, the pin can have a conical tip, with the smallest diameter located adjacent the guideway. According to another aspect of the invention, there is provided a tape printing device with a tape cassette receiving member in which a tape cassette can be detachably attached, the tape printing device comprising: printing means for printing an image on a tape provided in said tape cassette; and a cutting mechanism for cutting off a portion of printed tape, wherein the tape cassette comprises a housing having a wall portion which is arranged to support the tape during cutting, characterized in that a guiding mechanism is provided which is arranged for connecting the cutting mechanism and the wall portion during cutting and for aligning the cutting mechanism with respect to said wall portion. For a better understanding of the present invention and as to show how the same may be carried into effect, reference will now be made to the accompagnying drawings in which: Figure 1 shows a tape cassette of the invention; Figure 2 is a view of a cutter; Figure 3 is a view of a cutting blade; Figure 4 is a section through a cassette of the invention inserted into a tape printing device; Figure 5 shows a perspective view of another cassette together with a cutting mechanism of a tape printer. Figure 1 illustrates a tape cassette 10 according to the present invention. It comprises a housing in which a supply spool 12 with printing tape 14 is accomodated. The printing tape 14 comprises an image receiving layer to which a releasable backing layer is adhered. The user can peel the releasable backing layer from a printed portion of tape 14, and stick the self adhesive tape as a label against surfaces. The cassette of Figure 1 contains a direct thermal tape, thus no ink ribbon is present in the cassette 10. The tape 14 extends from the supply spool 12 through an outlet of the housing of the cassette 10 to a portion 22 of the wall of the housing on which a cutting location is defined, as explained later. At the cutting location, a slot 24 is defined in the wall portion 22. The tape is guided by means of hooks 31 downstream the slot 24. On both sides of the slot 24, reinforcements 38 are provided on the housing of the tape cassette 10, in which guideways 32,33 in the form of elongate channels are situated. The guideways 32,33 extend orthogonally to the feeding direction of the tape 14, and ortogonally to the length extension of the slot 24. The section of the guideways 32,33 is rectangular. A cutting mechanism for use with the tape cassette 10 of Figure 1 is shown in Figure 2. It comprises a blade holder 28 with pins 36 for holding a blade 30 as shown in Figure 3. The blade 30 comprises holes 30a for mounting the blade to the blade holder 28, whereby the pins 36 extend through the holes 30a. The blade 30 can alternatively be fixed by heatstake, ultrasonic weld or screws in the blade holder 28. The blade 30 has an angled cutting edge 29. Adjacent both sides of the space for accomodating the blade 30, the blade holder is provided with pins 34,35, which fit into the guideways 32,33 of the tape cassette 10 of Figure 1. The section of the pins 34,35 is rectangular. Figure 4 illustrates a horizontal section through a cassette receiving member of a printing device. The cassette receiving member is shown by the dotted line 2. The cassette receiving member 2 includes a thermal print head 4 and a platen 6 which cooperate to define a print location P in a manner which is known in the art. The print head 4 is pivotable about a pivot point 8 so that it can be brought into contact with the platen 6 for printing and moved away from the platen to enable a cassette 10 to be removed and replaced. The cassette inserted into the cassette receiving member 2 is denoted generally by reference numeral 10. The cassette holds the supply 12 of image receiving tape 14. The image receiving tape 14 is guided by a guide mechanism (which is not shown) through the cassette, out of the cassette, past the print location P to the cutting location. In the printing device illustrated in Figure 4, the platen 6 is driven so that it rotates to drive the image receiving tape 14 past the print location P during printing. In this way, tape is printed and fed out from the print location P during printing. In this way, tape is printed and fed out from the print location to the cutting location. The cutting location is like already mentioned provided at a location on a portion of the wall of the cassette which is close to the print location P. The portion of the wall of the cassette 10 where the cutting location 10 is defined is denoted by reference numeral 22. The slot 24 is defined in this wall portion and the image receiving tape 14 is fed past the print location P to the cutting location where it is supported by facing wall portions on either side of the slot 24. The printing device includes a cutting mechanism denoted generally by reference numeral 26. This cutting mechanism includes the blade holder 28 which carries the blade 30. The blade 30 cuts the image receiving tape 14 and then enters the slot 24 with the leading, part of its edge 29 first. It should be appreciated that the pins 34,35 of the blade holder 28 enter the guideways 32,33 of the tape cassette 10 simultaneously, such that the cutting mechanism is aligned with respect to the tape cassette 10 (or vice versa). Thus, the angle and position of the blade with respect to the slot 24 is always accurately determined, and the cut is performed under an angle of exactly 90° with regard to the feeding direction of the tape. It is further not possible that the blade 30 interferes with the side walls of the slot 24, what could be possible due to manufacturing tolerances in the state of the art. This functionality is additionally illustrated in Figure 5, which shows a tape cassette 10 together with a blade holder 28 in its ready-to-operate state. During cutting, pin 34 enters guideway 32, and pin 35 enters guideway 33. In Figure 5, the guideways 32,33 are somewhat shorter than in Figure 1, thus the guideways in Figure 5 are holes rather than channels, saving some material of the housing of the cassette 10.

Claims: A tape cassette detachably received in a tape printing device having a tape cassette receiving member (2) therein, said tape cassette (10) accommodating a printable tape (14) and comprising a housing having a wall portion (22) which is arranged to support the tape (14) during a cutting operation performed with a cutting mechanism of said tape printing device, characterized in that a guideway (32,33) is provided within said wall portion (22) of said cassette (10), wherein the guideway (32,33) is arranged for receiving a pin (34,35) connected to the cutting mechanism. A tape cassette according to claim 1, wherein the pin (34,35) and the guideway (32,33) connect the cutting mechanism and said wall portion (22) during cutting such that the cutting mechanism is aligned with respect to said wall portion (22). A tape cassette according to claim 1 or 2, wherein said guideway (32,33) has the form of a hole or a channel with a preferably rectangular section. A tape cassette detachably received in a tape printing device having a tape cassette receiving member (2) therein, said tape cassette (10) accommodating a printable tape (14) and comprising a housing having a wall portion (22) which is arranged to support the tape (14) during a cutting operation performed with a cutting mechanism of said tape printing device, characterized in that said wall portion (22) is arranged for interacting with a guide mechanism which connects the cutting mechanism and said wall portion (22) during cutting such that the cutting mechanism is aligned with respect to said wall portion (22). A tape cassette (10) according to claim 4, wherein the guide mechanism comprises a pin (34,35) which is arranged to protrude into a guideway (32,33) during cutting, wherein the guideway (32,33) has preferably a rectangular section. A tape cassette (10) according to claim 5, wherein the guideway (32,33) is provided within said wall portion (22) of said cassette (10), and has the form of a hole or a channel. A tape cassette (10) according to one of claims 1 - 3, 5 or 6, wherein a slot (24) on said wall portion (22) is provided, which is arranged such that a blade (30) of said cutting mechanism can travel into the slot (24) during cutting. A tape cassette according to one of claims 1 - 7, wherein the guideways (32,33) are provided in the vicinity of both lateral ends of a blade (30) of said cutting mechanism, when the tape cassette (10) is located within said tape cassette receiving member (2). A tape cassette according to one of claims 1 - 3 or 5 - 8, wherein the guideway (32,33) is of generally conical shape, with the larger diameter facing towards the pin (34,35). A tape printing device with a tape cassette receiving member (2) in which a tape cassette (10) is detachably attached, the tape printing device comprising: printing means for printing an image on a tape (14) provided in said tape cassette (10); and a cutting mechanism for cutting off a portion of printed tape (14), wherein the tape cassette (10) comprises a housing having a wall portion (22) which is arranged to support the tape (14) during cutting, characterized in that a guiding mechanism is provided which is arranged for connecting the cutting mechanism and the wall portion (22) during cutting and for aligning the cutting mechanism with respect to said wall portion (22). A tape printing device according to claim 10, wherein the guide mechanism comprises a pin (34,35) which is arranged to protrude into a guideway (32,33) during cutting. A tape printing device according to claim 11, wherein the pin (34,35) is mounted to the cutting mechanism. A tape printing device according to one of claims 10 - 12, wherein a slot (24) on said wall portion (22) is provided, which is arranged such that a blade (30) of said cutting mechanism can travel into the slot (24) during cutting. A tape printing device according to one of claims 10 - 13, wherein two pins (34,35) are provided in the vicinity of both lateral ends of a blade (30) of said cutting mechanism. A tape printing device according to one of claims 10 - 14, wherein the pin (34,35) has a conical tip, with the smaller diameter facing towards the guideway (32,33). A tape printing device according to one of claims 10 - 15, wherein the pin (34,35) has a rectangular section.

Inventors: COCKERILL SAM, PANAYI COSTA, COCKERILL, SAM, PANAYI, COSTA
Applicants: ESSELTE NV, ESSELTE N.V.
Application year: 1997
Main classification: B41J11
IPC codes: B41J11, B41J3