Patent Description:
There is conventionally known various printing devices proposed for printing characters and the like on a long continuous strip of printing tape (see Patent Document <NUM>, for example). The printing tape described in Patent Document <NUM> has a heat-sensitive layer, and an overcoat layer. The heat-sensitive layer is formed on the surface of the printing tape on which characters and the like are to be printed and can produce color when exposed to heat from heating elements in a thermal head. The overcoat layer is provided when the heat-sensitive layer must be protected from an adhesive. Examples of compounds that are used to form the overcoat layer include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone, polyacrylamide, starch, gelatin, and methoxycellulose.

JPH06328850 A discloses a thermal head constituted so that along with formation of a heat sensitizer layer on a base sheet an overcoat layer is formed on the heat sensitizer layer, furthermore, a protective layer consisting mainly of normal temperature curing silicone resin is formed on the overcoat layer and printing is performed while sliding the thermal head relatively on the protective layer.

JPH06127062 A discloses a printing tape comprised by forming a heat sensitizer layer and overcoat layer on one surface of a base sheet and sticking peeling paper to the other surface of the base sheet through an adhesive layer is built in a tape cassette. With this construction, a printing ribbon and a member running the printing ribbon within the tape cassette become unnecessary at all and running of the printing tape is performed stably. JPH06127090 A discloses an overcoating layer containing ultraviolet ray absorbent dispersed therein is provided on a heat sensitizer layer formed on one surface of a base material sheet. Thus, both a printed part and a nonprinted part of a tape for printing are effectively protected against an ultraviolet ray to prevent the printed part from being faded as much as possible and to also prevent the nonprinted part from being discolored. JPH0834163 A discloses a thermal recording material obtained by providing a thermal color forming layer on the single surface of a base material and providing a heat- resistant protective layer on the surface opposite to the base material of the thermal color forming layer. A support is formed by providing pressure-sensitive adhesive layers on both surfaces of a thin base material and providing a release liner on the pressure-sensitive adhesive layer on the side not coming into contact with the thermal recording material. <CIT> discloses a tape cassette having a rear indentation formed between the periphery of a cassette case and a tape housing area on a rear edge side of a bottom wall. A rear indicator portion for specifying the color information related to a tape is provided in a specified area included in the rear indentation. A tape color is specified by whether or not a protrusion is formed in a lateral information section among a plurality of lateral information sections included in the rear indicator portion, and a character color is specified by whether or not a protrusion is formed in a lateral information section. JPH09164637 A discloses a thermal printing self-adhesive sheet constituted by providing a thermal color forming layer on the single surface of a heat insulating sheet and providing a release coating layer composed of a curing film of a silicone polymer containing two or more acryloyl groups or methacryloyl groups in its molecule on the upper surface thereof and providing a self-adhesive layer to the other surface of the heat insulating sheet. By this constitution, the release coating layer can be provided while keeping the thermal color properties of a thermal printing sheet.

However, the printing tape disclosed in Patent Document <NUM> has insufficient resistance to temperature and water (humidity) for protecting the heat-sensitive layer from adhesives, and characters and the like printed on this printing tape often become faint due to the effects of temperature, humidity, and the like.

In view of the foregoing, it is an object of the present invention to provide a printing tape cassette housing a printing tape with better resistance to temperature and water (humidity) than conventional printing tape.

In order to attain the above and other objects, according to the present invention, there is provided a printing tape cassette as set out in the appended set of claims.

Next, embodiments of the present invention will be described while referring to the accompanying drawings. The referenced drawings are used to describe the technical features made possible with the present invention. The configurations of the apparatuses described below are merely examples, and the present invention is not intended to be limited to these configurations.

First, a printing tape cassette <NUM> and a printing device <NUM> (hereinafter referred to as "device") in which the printing tape cassette <NUM> is mounted will be described with reference to <FIG>. In the following description, the lower-left side, upper-right side, lower-right side, and upper-left side of the device <NUM> in <FIG> are respectively defined as the front side, rear side, right side, and left side of the device <NUM>. The lower-right side, upper-left side, upper-right side, and lower-left side of the printing tape cassette <NUM> in <FIG> are respectively defined as the front side, rear side, right side, and left side of the printing tape cassette <NUM>. A group of gears shown in <FIG> that include gears <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> is actually covered and hidden by the bottom surface of a cavity 8a. However, the bottom surface of the cavity 8a is not shown in <FIG> for the purpose of describing this group of gears. <FIG> also schematically depicts side walls that form a periphery around a cassette housing section <NUM>, but this is merely a schematic diagram and the side walls are drawn thicker than the thickness of the actual side walls. Further, to facilitate understanding, the printing tape cassette <NUM> mounted in the cassette housing section <NUM> in <FIG> is depicted without an upper case 31a.

The structure of a device <NUM> in which a printing tape cassette <NUM> is mounted will be described with reference to <FIG>. As shown in <FIG>, the device <NUM> is a general-purpose tape printing device in which various types of printing tape cassettes can be commonly used, including a thermal type, a receptor type, and a laminated type. The device <NUM> is provided with a main unit cover <NUM>, a keyboard <NUM>, a display <NUM>, and a cassette cover <NUM>. The main unit cover <NUM> has a rectangular parallelepiped shape in a plan view. The keyboard <NUM> is arranged on the front side of the main unit cover <NUM>. The keyboard <NUM> includes character keys for alphabetic and numeric characters and symbols, and various function keys. The display <NUM> is provided on the rear side of the keyboard <NUM>. The display <NUM> can display inputted alphanumeric characters and symbols. The cassette cover <NUM> is provided on the rear side of the display <NUM>. The cassette cover <NUM> is opened and closed when replacing the printing tape cassette <NUM>. While not shown in the drawings, a discharge slit is provided toward the rear on the left side of the main unit cover <NUM>. Tape that has been printed is discharged from the main unit cover <NUM> through this discharge slit. A discharge window is also formed on the left side surface of the cassette cover <NUM>. The discharge slit is exposed on the outside of the main unit cover <NUM> through the discharge window when the cassette cover <NUM> is in a closed state.

The internal structure of the main unit cover <NUM> under the cassette cover <NUM> will be described next with reference to <FIG>. As shown in <FIG>, a cassette housing section <NUM> is provided inside the main unit cover <NUM> in a region corresponding to the cassette cover <NUM>. The printing tape cassette <NUM> can be freely inserted into and removed from the cassette housing section <NUM>. The cassette housing section <NUM> includes a cavity 8a, and a cassette support part 8b. The cavity 8a is formed as a depression that substantially corresponds to the shape of a bottom surface 30b of a cassette case <NUM> described later and has a flat bottom surface. The cassette support part 8b is a flat surface that extends horizontally from the outer edges of the cavity 8a. The cassette support part 8b has a rectangular shape elongated in the left-right direction in a plan view and corresponds substantially to the shape of the printing tape cassette <NUM> in a plan view. In a plan view, the rear edge of the cavity 8a has two arcs formed adjacent to each other in the left-right direction.

As shown in <FIG>, two positioning pins <NUM> and <NUM> are provided at two locations on the cassette support part 8b. More specifically, the positioning pin <NUM> is provided on the left side of the cavity 8a and the positioning pin <NUM> is provided on the right side of the cavity 8a. The positioning pins <NUM> and <NUM> are disposed in positions respectively corresponding to pin holes <NUM> and <NUM> when the printing tape cassette <NUM> is mounted in the cassette housing section <NUM>. The pin holes <NUM> and <NUM> are two recessed parts formed in the bottom surface of the printing tape cassette <NUM>. When the printing tape cassette <NUM> is mounted in the cassette housing section <NUM>, the positioning pins <NUM> and <NUM> are respectively inserted into the pin holes <NUM> and <NUM>, thereby supporting the printing tape cassette <NUM> from below at left and right positions on the peripheral portion of the printing tape cassette <NUM>.

The cassette housing section <NUM> is also provided with a conveying mechanism that conveys tape drawn out from the printing tape cassette <NUM>, a printing mechanism that prints characters and the like on the surface of the tape, and the like. As shown in <FIG>, a head holder <NUM> is fixedly disposed on the front side of the cassette housing section <NUM>, and a thermal head <NUM> provided with heating elements (not shown) is mounted in the head holder <NUM>.

A tape feed motor <NUM> is arranged on the outer side of the cassette housing section <NUM> (the upper-right side in <FIG>). The tape feed motor <NUM> is configured of a stepping motor. A drive gear <NUM> is fixed to the lower end of a drive shaft in the tape feed motor <NUM>. The drive gear <NUM> is meshed with a gear <NUM> through an opening, and the gear <NUM> is meshed with a gear <NUM>. A ribbon take-up shaft <NUM> is disposed in an upright state on the top surface of the gear <NUM>. The ribbon take-up shaft <NUM> drives a ribbon take-up spool <NUM> described later to rotate. A gear <NUM> is also meshed with the gear <NUM>, a gear <NUM> is meshed with the gear <NUM>, and a gear <NUM> is meshed with the gear <NUM>. A tape drive shaft <NUM> is disposed in an upright state on the top surface of the gear <NUM>. The tape drive shaft <NUM> drives a tape drive roller <NUM> described later to rotate.

When the tape feed motor <NUM> is driven to rotate in the counterclockwise direction while the printing tape cassette <NUM> is mounted in the cassette housing section <NUM>, the ribbon take-up shaft <NUM> is also driven to rotate in the counterclockwise direction via the drive gear <NUM>, gear <NUM>, and gear <NUM>. The rotation of the ribbon take-up shaft <NUM> drives the ribbon take-up spool <NUM> in the printing tape cassette <NUM> to rotate. The ribbon take-up spool <NUM> is mounted over the ribbon take-up shaft <NUM>. The rotation of the gear <NUM> is also transmitted to the tape drive shaft <NUM> via the gear <NUM>, gear <NUM>, and gear <NUM>, thereby driving the tape drive shaft <NUM> to rotate in the clockwise direction. The rotation of the tape drive shaft <NUM> drives the tape drive roller <NUM> in the printing tape cassette <NUM> to rotate. The tape drive roller <NUM> is mounted over the tape drive shaft <NUM>.

As shown in <FIG>, an arm-like platen holder <NUM> is pivotably supported about a support shaft 12a provided on the front side of the head holder <NUM>. A platen roller <NUM> and a movable feed roller <NUM> are both rotatably supported on the distal end of the platen holder <NUM>. The platen roller <NUM> is disposed so as to be capable of contacting and separating from the thermal head <NUM>, while the movable feed roller <NUM> is disposed so as to be capable of contacting and separating from the tape drive roller <NUM> that is mounted over the tape drive shaft <NUM>.

A release lever (not shown) is coupled with the platen holder <NUM>. The release lever moves in the left-right direction in association with the opening and closing of the cassette cover <NUM>. Specifically, when the cassette cover <NUM> is opened, the release lever moves rightward, and the platen holder <NUM> moves toward a standby position (the position depicted with dashed lines in <FIG>). When moving toward the standby position, the platen holder <NUM> separates from the cassette housing section <NUM>, allowing the printing tape cassette <NUM> to be inserted into or removed from the cassette housing section <NUM>. A coil spring (not shown) constantly urges the platen holder <NUM> elastically toward the standby position (counterclockwise in a plan view).

When the cassette cover <NUM> is closed, on the other hand, the release lever moves leftward, and the platen holder <NUM> moves toward a printing position depicted with solid lines in <FIG>. When moving toward the printing position, the platen holder <NUM> moves in a direction approaching the cassette housing section <NUM>. When a thermal-type printing tape cassette <NUM> possessing a first tape <NUM> and a second tape <NUM> is mounted in the cassette housing section <NUM>, as illustrated in <FIG>, the platen roller <NUM> presses the first tape <NUM> against the thermal head <NUM> while the movable feed roller <NUM> presses the first tape <NUM> and second tape <NUM> against the tape drive roller <NUM>.

As shown in <FIG>, a conveying path for conveying the printing tape <NUM> is provided from the tape discharge part <NUM> to the discharge slit (not shown) in the device <NUM>. A cutting mechanism <NUM> is disposed on the conveying path for cutting the printing tape <NUM> at a prescribed position. The cutting mechanism <NUM> is configured of a fixed blade <NUM>, and a movable blade <NUM> that opposes the fixed blade <NUM> and is supported to be capable of moving in the front-rear direction. A cutter motor (not shown) is provided for moving the movable blade <NUM> in the front-rear direction.

Next, the structure of the printing tape cassette <NUM> will be described with reference to <FIG>. As shown in <FIG>, the printing tape cassette <NUM> has a cassette case <NUM>, the first tape <NUM>, and the second tape <NUM>. As shown in <FIG>, overall, the cassette case <NUM> is a substantially rectangular parallelepiped (box-shaped) housing with corners that are rounded in a plan view. The cassette case <NUM> is configured of a lower case 31b and an upper case 31a. The lower case 31b includes a bottom surface 30b of the cassette case <NUM>. The upper case 31a includes a top surface 30a of the cassette case <NUM> and is fixed to the top of the lower case 31b. When the upper case 31a and lower case 31b are fixed together, a side surface 30c of a prescribed height is formed along the outer edges of the top surface 30a and bottom surface 30b. In other words, the cassette case <NUM> is a box-like casing that includes the top surface 30a and bottom surface 30b constituting a pair of rectangular-shaped planar surfaces oppositely arranged in the vertical direction, and the side surface 30c formed at a prescribed height along the outer edges of the top surface 30a and bottom surface 30b (in this example, four sides surfaces including the front surface, rear surface, left side surface, and right side surface). In the cassette case <NUM>, the side surface 30c need not enclose the entire peripheries of the top surface 30a and bottom surface 30b. For example, an opening may be provided in a portion of the side surface 30c (the rear surface, for example) that exposes the interior of the cassette case <NUM>, and a boss connecting the top surface 30a to the bottom surface 30b may be provided in a position confronting this opening. The vertical dimension of the cassette case <NUM> (i.e., the direction in which the top surface 30a and bottom surface 30b oppose each other) substantially corresponds to the direction in which the printing tape cassette <NUM> is inserted into and removed from the cassette housing section <NUM>.

The front side of the cassette case <NUM> is provided with an arm part <NUM>, a head insertion section <NUM>, guide parts <NUM>, and a tape discharge part <NUM>. The arm part <NUM> extends diagonally leftward and forward from the right front portion of the printing tape cassette <NUM>. The extended direction of the arm part <NUM> is aligned with the longitudinal direction of the cassette case <NUM> (left-right direction). An opening 34a that is elongated vertically is formed in the distal end (left end) of the arm part <NUM>. When the cassette case <NUM> is assembled by joining the upper case 31a and lower case 31b together, a conveying path is formed inside the arm part <NUM> for guiding conveyance of the first tape <NUM>. As shown in <FIG>, after the first tape <NUM> is guided along this conveying path, the first tape <NUM> is discharged through the opening 34a into the head insertion section <NUM> (and more specifically an opening <NUM> described later). Thus, the opening 34a is provided in the side surface 30c and constitutes the portion in the cassette case <NUM> through which the first tape <NUM> guided along the prescribed conveying path passes from the inside to the outside of the cassette case <NUM>.

The head insertion section <NUM> is a space surrounded by a rear surface <NUM> of the arm part <NUM>, and a peripheral surface of the cassette case <NUM> formed continuously with the rear surface <NUM> of the arm part <NUM>, and has a general rectangular shape in a plan view. The head insertion section <NUM> penetrates the printing tape cassette <NUM> vertically. The head insertion section <NUM> is provided in a forwardly biased position in the cassette case <NUM> (i.e., in a position biased toward the side opposite the second tape <NUM> and first tape <NUM>). As shown in <FIG>, the head insertion section <NUM> also communicates with the outside of the printing tape cassette <NUM> at the front side thereof through an opening <NUM> formed in the front surface of the printing tape cassette <NUM>. The head holder <NUM> that supports the thermal head <NUM> of the device <NUM> is inserted into the head insertion section <NUM>. The thermal head <NUM> prints on the first tape <NUM> discharged through the opening 34a of the arm part <NUM> in the opening <NUM> where the first tape <NUM> is exposed to the outside of the cassette case <NUM>.

The guide parts <NUM> are provided on the side surface 30c upstream of the tape drive roller <NUM>. After the first tape <NUM> is passed through the opening 34a, the guide parts <NUM> guide the first tape <NUM> from outside of the cassette case <NUM> to inside the cassette case <NUM>. The guide parts <NUM> in this example are a pair of bar-shaped members extending vertically. The guide parts <NUM> guide the printed first tape <NUM> from the downstream side of the thermal head <NUM> toward the tape discharge part <NUM> while restricting movement of the first tape <NUM> vertically (in the direction along the tape width). Hence, the guide parts <NUM> ensure that the printed first tape <NUM> is properly bonded to the second tape <NUM> with no positional displacement therebetween.

The tape discharge part <NUM> is a plate-shaped member spanning between the top surface 31A and bottom surface 31B of the cassette case <NUM>. The tape discharge part <NUM> is slightly separated in the forward direction from the front end on the left side surface of the cassette case <NUM>. The tape discharge part <NUM> guides the printing tape <NUM> conveyed over the guide parts <NUM> and tape drive roller <NUM> into a passage formed in the front end on the left side surface of the lower case 31b and discharges the printing tape <NUM> through a tape discharge opening (not shown) at the downstream end of the passage.

As shown in <FIG>, pin holes <NUM> and <NUM> are provided in the bottom surface 30b to correspond to the positioning pins <NUM> and <NUM> of the device <NUM> described above. Specifically, a recessed part provided to the rear of (above in <FIG>) a support hole <NUM> (described later), which is disposed in the left-front portion of the cassette case <NUM>, constitutes the pin hole <NUM> in which the positioning pin <NUM> is inserted. A recessed part provided near the center region on the right edge of the cassette case <NUM> constitutes the pin hole <NUM> in which the positioning pin <NUM> is inserted.

Support holes 65a, 66a, and 67a (see <FIG>) are formed in the upper case 31a, and support holes 65b, 66b, and 67b (see <FIG>) are formed in the lower case 31b for rotatably supporting a first tape spool <NUM> and a second tape spool <NUM> described later, as well as the ribbon take-up spool <NUM>.

As shown in <FIG>, the first tape <NUM> is a long strip of tape wound in a roll about the second tape spool <NUM>. As shown in <FIG>, the first tape <NUM> is configured of a first protective layer <NUM>, a heat-sensitive layer <NUM>, and a second protective layer <NUM>. The first protective layer <NUM> is provided on the heat-sensitive layer <NUM>. The first protective layer <NUM> transmits light. The first protective layer <NUM> should be capable of transmitting a sufficient amount of light for observing color development in the heat-sensitive layer <NUM>. For example, the first protective layer <NUM> may be formed of a resin, such as polyethylene (PE), polypropylene (PP), ethylene vinyl acetate (EVA) copolymer, ethylene methacrylic acid (EMMA) copolymer, polybutene (PB), polybutadiene (BDR), polymethylpentene (PMP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyimide (PI), polyetherimide (PEI), polyetherketone (PEK), polyether ether ketone (PEEK), nylon (NY), polyamide (PA), polycarbonate (PC), polystyrene (PS), expanded polystyrene (FS/EPS), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), saponified ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVA), plain transparent (PT) cellophane, moisture-proof sealable transparent (MST) cellophane, polyacrylonitrile (PAN), vinylon (VL), polyurethane (PU), and triacetyl cellulose (TAC). For example, the first protective layer <NUM> may be formed of a metal foil (aluminum foil or copper foil), a vacuum metalized (VM) film, or the like, or may be configured of one of various types of paper, including translucent paper, washi, wood-free paper, dust-free paper, glassine paper, clay-coated paper, resin-coated paper, laminated paper (polyethylene-laminated paper, polypropylene-laminated paper, etc.), synthetic paper, kraft paper, and the like. The first protective layer <NUM> may also be formed of a nonwoven cloth or a glass cloth, for example.

The first protective layer <NUM> is provided to protect the heat-sensitive layer <NUM> from oil, dirt, and the like and to enhance resistance to various matter (resistance to plasticizers, water, oil, and chemicals). The first protective layer <NUM> is formed of a water-soluble resin (polyvinyl alcohol, etc.), a resin emulsion, and the like. The heat-sensitive layer <NUM> produces color at temperatures within a prescribed range. The heat-sensitive layer <NUM> includes leuco dye, developer, auxiliary agents (fillers, binders, lubricants, antioxidants, water-resistant additives, film-forming assistants, pigments, stabilizers, dispersants, antifoaming agents, etc.), and the like.

The second protective layer <NUM> is provided on the side of the heat-sensitive layer <NUM> opposite the first protective layer <NUM>. The second protective layer <NUM> includes at least one resin from among fluorine-based resins, epoxy/polyester-based resins. Resins included in the second protective layer <NUM> are preferably polyvinyl fluoride resins (fluorides), polyvinylidene fluoride resins (difluorides), polychlorotrifluoroethylene resins (trifluorides), and polytetrafluoroethylene resins (tetrafluorides), and most preferably polytetrafluoroethylene resins. The second protective layer <NUM> is formed of material that transfers heat. As shown in <FIG>, the second tape spool <NUM> about which the first tape <NUM> is wound is disposed so as to be rotatable via the support hole 66a (see <FIG>) and the support hole 66b (see <FIG>). The second protective layer <NUM> in the section of the first tape <NUM> positioned between the opening 34a and guide parts <NUM> confronts the thermal head <NUM> provided in the cassette housing section <NUM> of the device <NUM>. As shown in <FIG>, the second tape <NUM> is wound in a roll about the first tape spool <NUM> and is accommodated in the interior space of the cassette case <NUM>. As shown in <FIG>, the second tape <NUM> is provided with a first adhesive layer <NUM>, and a base material <NUM>. The first adhesive layer <NUM> includes at least one adhesive from among an emulsion-type adhesive containing an acrylic polymer and a rubber-based adhesive and compounded with a tackifying resin and silicone-based adhesive. The first adhesive layer <NUM> is bonded to the second protective layer <NUM> of the first tape <NUM>.

The base material <NUM> is bonded to the surface of the first adhesive layer <NUM> on the side opposite the surface bonded to the second protective layer <NUM>. The base material <NUM> in this example is a release paper. The base material <NUM> may be configured of paper, film, or synthetic paper. In the preferred embodiment, the surface of the base material <NUM> on the first adhesive layer <NUM> side is subjected to a non-silicone-based release treatment, and the surface of the base material <NUM> on the opposite side from the first adhesive layer <NUM> is also subjected to a non-silicone-based release treatment.

The non-silicone-based release agent used in this release treatment is a pendant-type polymer of a long-chain fatty acid produced by reacting an aliphatic isocyanate with polyvinyl alcohol, or the like. A non-silicone-based release agent can be used to form a release coating simply by applying a liquid composition formed by dissolving the release agent in solvent to a supporting medium and drying the liquid composition, for example, without needing to use a special catalyst or to perform heat treatment or other processes when forming the release coating. As shown in <FIG>, the first tape spool <NUM> is disposed so as to be rotatable via the support hole 65a (see <FIG>) and the support hole 65b (see <FIG>). The second tape <NUM> is wound about the first tape spool <NUM> such that the base material <NUM> faces outward and is arranged and conveyed in a manner that brings the first adhesive layer <NUM> against the second protective layer <NUM> of the first tape <NUM>. In other words, the second tape <NUM> is wound in a roll about the first tape spool <NUM> with the first adhesive layer <NUM> facing inward.

When the device <NUM> performs printing, the tape drive roller <NUM> driven to rotate via the tape drive shaft <NUM> pulls the first tape <NUM> from the second tape spool <NUM> in cooperation with the movable feed roller <NUM>. The first tape <NUM> drawn off the second tape spool <NUM> is redirected leftward at the bottom-right corner of the cassette case <NUM> in a plan view and conveyed along the conveying path in the arm part <NUM>. The first tape <NUM> is supplied through the opening 34a of the arm part <NUM> into the opening <NUM> and is conveyed between the thermal head <NUM> and platen roller <NUM>. The first tape <NUM> receives heat from the thermal head <NUM> on the second protective layer <NUM> side while between the opening 34a and the guide parts <NUM>. This heat produces printed characters, graphics, symbols, and the like in the heat-sensitive layer <NUM>. The tape drive roller <NUM> and movable feed roller <NUM> work in concert to convey the printed first tape <NUM> onto the prescribed conveying path while the first tape <NUM> is guided by the guide parts <NUM> so that the first adhesive layer <NUM> of the second tape <NUM> adheres to the second protective layer <NUM> of the first tape <NUM> (see <FIG>). The first tape <NUM> having the second tape <NUM> affixed thereto becomes the printing tape <NUM>. This printing tape <NUM> is conveyed toward the tape discharge part <NUM> and cut by the cutting mechanism <NUM>.

In the printing tape cassette <NUM>, the first tape <NUM> may be arranged such that the first protective layer <NUM> opposes the thermal head <NUM> provided in the cassette housing section <NUM> of the device <NUM> while passing between the opening 34a and the guide parts <NUM>, as illustrated in <FIG>. In this case, the first protective layer <NUM> is preferably formed of a material that conveys heat.

The second tape used to form the printing tape <NUM> may be configured to include a double-sided tape base material <NUM>, as in a second tape <NUM> illustrated in <FIG>. In this case, the second tape <NUM> may include a second adhesive layer <NUM> affixed to the side of the double-sided tape base material <NUM> opposite the first adhesive layer <NUM>, and a release paper <NUM> affixed to the second adhesive layer <NUM>.

The cassette case <NUM>, top surface 30a, bottom surface 30b, and side surface 30c are respective examples of the cassette case, first surface, second surface, and third surface in the present invention. The first tape <NUM>, heat-sensitive layer <NUM>, first protective layer <NUM>, and second protective layer <NUM> are respective examples of the first tape, heat-sensitive layer, first protective layer, and second protective layer in the invention. The second tape <NUM>, first adhesive layer <NUM>, and base material <NUM> are respective examples of the second tape, the first adhesive layer, and the base material in the invention. In the second variation, the double-sided tape base material <NUM> is an example of the base material in the invention.

The printing characteristics of the printing tape <NUM> were evaluated by testing a tape whose second protective layer includes polyvinyl alcohol as a comparative example, and a tape whose second protective layer includes fluorine-based resin as an example. The same heat-sensitive layer, first adhesive layer, and second adhesive layer were used in both the comparative example and the example. Specifically, as indicated in <FIG>, the heat-sensitive layer used in the experiments was a common heat-sensitive layer that included leuco dye, developer, auxiliary agents (fillers, binders, lubricants, antioxidants, water-resistant additives, film-forming assistants, pigments, stabilizers, dispersants, antifoaming agents, etc.), and the like. The first protective layer was formed of PET at a thickness of <NUM>. The first adhesive layer was formed with an acrylic-based adhesive (solvent). The second protective layer in the comparative example was formed of polyvinyl alcohol at a thickness of approximately <NUM>. The second protective layer in the example was formed of polytetrafluoroethylene resin (tetrafluoride) at a thickness of approximately <NUM>. The width of the printing tape (vertical dimension in <FIG>) was <NUM>, and the characters ABC were printed in <NUM>-point Gothic type using the same printing device for both tests. Printing tape according to both the comparative example and the example were printed in black characters and left for seven days under the high-temperature and high-humidity conditions of <NUM> and <NUM>% humidity, after which the printing characteristics were evaluated. A Macbeth densitometer (with black filter) was used to evaluate the printing characteristics by measuring optical density (OD values).

As shown in <FIG>, the black color forming the characters on the printed tape according to the comparative example disappeared after being exposed for seven days to high temperature and high humidity. On the other hand, the black characters remained vibrant in the printed tape according to the example after seven days under high-temperature and high-humidity conditions, with an OD value of <NUM>. Thus, a marked difference in resistance to temperature and water (humidity) was observed in the printing tape according to the preferred embodiment and the printing tape according to the comparative example.

Even though the first adhesive layer <NUM> of the second tape <NUM> is affixed to the second protective layer <NUM> of the first tape <NUM> after the printing process, the second protective layer <NUM> in the printing tape cassette <NUM> protects the heat-sensitive layer <NUM> from the first adhesive layer <NUM>. As confirmed in the evaluation results, the resin used to form the second protective layer <NUM> in the preferred embodiment can better protect the heat-sensitive layer <NUM> from the effects of temperature, humidity, and the like than the resin emulsion and water-soluble resins, such as polyvinyl alcohol, used in the overcoat layer of the conventional printing tape. Further, since the resin used to form the second protective layer <NUM> has relatively low polarity, the first adhesive layer <NUM> can be made to adhere well to the second protective layer <NUM> by forming the first adhesive layer <NUM> of an adhesive exhibiting good adhesive properties with nonpolar adherends.

The printing tape cassette <NUM> is provided with release paper as the first adhesive layer <NUM>. Thus, the printing tape can be affixed to a desired object after peeling off the base material <NUM> (release paper).

The surface of the base material <NUM> (release paper) on the first adhesive layer <NUM> side is treated with a non-silicone-type release agent. Thus, the printing tape cassette <NUM> can decrease blocking between the adhesive in the first adhesive layer <NUM> and the base material <NUM> (release paper) and reduce the release force. The surface of the base material <NUM> (release paper) on the side opposite the first adhesive layer <NUM> side is also subjected to treatment with a non-silicone-release agent. Thus, the printing tape cassette <NUM> can decrease blocking between the adhesive and the base material <NUM> (release paper) and can reduce the release force, even when the first adhesive layer <NUM> is affixed to the surface of the base material <NUM> (release paper) on the opposite side of the first adhesive layer <NUM>.

The second tape <NUM> according to the second variation includes the double-sided tape base material <NUM> as the base material affixed to the first adhesive layer <NUM>. The printing tape cassette <NUM> in this variation also includes the second adhesive layer <NUM> affixed to the side of the double-sided tape base material <NUM> opposite the first adhesive layer <NUM>, and the base material <NUM> (release paper) affixed to the second adhesive layer <NUM>. With the printing tape cassette <NUM> according to the second variation, the thickness, strength, and the like of the printing tape configured by affixing the second tape <NUM> to the first tape <NUM> can be adjusted according to the double-sided tape base material <NUM>. The printing tape of the printing tape cassette <NUM> can be affixed to a desired object after peeling off the base material <NUM> (release paper).

The printing tape cassette <NUM> is mounted in the cassette housing section <NUM> of the device <NUM>, which includes the thermal head <NUM>, and the second protective layer <NUM> of the section of the first tape <NUM> positioned between the opening 34a and the guide parts <NUM> confronts the thermal head <NUM>. Accordingly, the printing tape cassette <NUM> can facilitate the transfer of heat from the thermal head <NUM> to the heat-sensitive layer <NUM> to produce color in the heat-sensitive layer <NUM> properly. Further, since second protective layer <NUM> is formed of a material that transfers heat to the heat-sensitive layer <NUM>, the printing tape cassette <NUM> can transfer heat from the thermal head <NUM> to the heat-sensitive layer <NUM> to produce color in the heat-sensitive layer <NUM>.

When the printing tape cassette <NUM> according to the first variation is mounted in the cassette housing section <NUM> of the device <NUM>, the first protective layer <NUM> of the first tape <NUM> confronts the thermal head <NUM>. Accordingly, the printing tape cassette <NUM> can easily transfer heat from the thermal head <NUM> to the heat-sensitive layer <NUM> to produce color in the heat-sensitive layer <NUM> properly. Further, since first protective layer <NUM> of the printing tape cassette <NUM> is formed of a material that transfers heat to the heat-sensitive layer <NUM>, the printing tape cassette <NUM> can transfer heat from the thermal head <NUM> to the heat-sensitive layer <NUM> to produce color in the heat-sensitive layer <NUM>.

Printing tape and printing tape cassette in the present invention are not limited to the embodiments as described above. The present invention may be worked by making various changes. The scope of the invention however is defined by the appended claims. For example, following changes may be added appropriately.

Claim 1:
A printing tape cassette (<NUM>) comprising:
a cassette case (<NUM>) having a first surface (30a), a second surface (30b) facing the first surface, and a third surface (30c) connecting the first surface to the second surface, a combination of the first surface, the second surface, and the third surface defining an internal space, the cassette case being attached to a cassette housing section of a printing device (<NUM>);
a first tape (<NUM>) accommodated in the internal space and wound in a roll, the first tape comprising:
a heat-sensitive layer (<NUM>) producing color at temperatures within a prescribed range;
a first protective layer (<NUM>) provided on the heat-sensitive layer, light being allowed to transmit through the first protective layer; and
a second protective layer (<NUM>) provided on the side of the heat-sensitive layer opposite the first protective layer, the second protective layer containing fluorine-based resin; and
a second tape (<NUM>) accommodated in the internal space and wound in a roll, the second tape comprising:
a first adhesive layer (<NUM>) containing emulsion-type adhesive compounded with tackifying resin and containing acrylic polymer and rubber-based adhesive, the first adhesive layer being adhered to the second protective layer; and
a base material (<NUM>, <NUM>) adhered to the side of the first adhesive layer opposite a surface of the first adhesive layer adhered to the second protective layer.