Platen locking mechanism for thermal transfer recording apparatus

Abstract: A thermal transfer recording apparatus wherein printing on record paper (3) is performed with the record paper fixed on a platen roller (1) is constituted such that, when the record paper (3) is to be fixed, transmission of power to the platen roller (1) is interrupted and the platen roller (1) is fixedly held at a predetermined position, which enables realization of a transporting system for a transport system of a thermal transfer recording apparatus of the record paper (3) fixing type which system includes a single motor (9) therein.

Description: BACKGROUND OF THE INVENTION A thermal transfer recording apparatus records on record paper by pressing ink paper and the record paper with the ink paper positioned outwardly of the record paper against a platen roller and heating the ink paper from above with a thermal head. In such thermal transfer recording apparatus, the record paper is fixedly held in most cases on the platen roller using a fixing element in order to assure the accuracy in position of transfer record. In an apparatus of the type mentioned which employs such conventional system, supplying and discharging of record paper, winding of ink paper and so forth are performed by individual motors separate from a motor for the rotational driving of the platen roller. It is to be noted that such apparatus as described above is disclosed, for example, in Japanese Utility Model Application Laid-Open No. 62-109953 and Japanese Utility Model Application Laid-Open No. 63-60343. Such conventional apparatus requires motors for the exclusive use for supplying and discharging of record paper, winding of ink paper and so forth and involves motor driving circuits of a large scale, which requires a rise of the cost of the apparatus. EP-A-0 180 370 discloses a paper feed and eject control apparatus for a printer in which a printing paper sheet is automatically fed by a paper feed roller through a paper feed guide and is ejected by a paper eject roller through a paper eject guide. Both of the rollers are driven by a single roller drive motor. However, the structure of the mechanical parts involved has a relatively complex structure. It is an object of the present invention to provide a thermal transfer recording apparatus which includes a single motor by which rotational driving of a platen roller, supplying and discharging of record paper, winding of ink paper and so forth can be realized. SUMMARY OF THE INVENTION The present invention relates to a recording apparatus of the thermal transfer type, and more particularly to a platen locking mechanism suitable for use with platen roller driving means of the type wherein printing is performed on record paper fixed to a platen roller. In a thermal transfer recording apparatus according to the present invention, a system for transmitting rotational power to a platen roller has a platen roller non-driving position at which rotational power is not transmitted to the platen roller, and rotation of the platen roller is prevented upon supplying or discharging of record paper and so forth. Further, also driving for transporting record paper from the platen roller to a record paper fixing mechanism section is performed by a platen roller driving motor so that considerable reduction in cost of the mechanisms and electric circuits can be realized without the necessity of a motor for the exclusive use for the supplying and discharging of paper. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic plan view of a thermal transfer recording apparatus according to the present invention; Fig. 2 is a semi-sectional view of a platen roller; Fig. 3 is a right-hand side elevational view of the platen roller of Fig. 2; Fig. 4(a) is an enlarged view of a right portion of Fig. 2; Fig. 4(b) is a right-hand side elevational view of the portion shown in Fig. 4(a); Fig. 5 is a side elevational view of a platen roller body; Fig. 6 is a front elevational view of a gear block of a rotational driving system; Fig. 7 is a sectional view taken along line B-B and is a front elevational view showing a driving system of the apparatus; Fig. 8 is a schematic view showing a change-over gear and operation of the same; Fig. 9 is a sectional view taken along line A-A of Fig. 1 and is a front elevational view showing a paper supplying condition of the apparatus; Fig. 10 is an enlarged view of part of the platen roller shown in Fig. 9; Fig. 11 is a front elevational view showing a printing condition of the apparatus; Fig. 12 is an enlarged view of part of the platen roller shown in Fig. 11; Fig. 13 is a front elevational view showing a discharging condition of the apparatus; and Fig. 14 is an enlarged view of part of the platen roller shown in Fig. 13. DESCRIPTION OF PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to Figs. 1 to 14. Figs. 2 to 5 are schematic views showing a platen roller of a thermal transfer recording apparatus around for winding record paper therearound. A platen roller 1 includes a rubber member formed in a cylindrical profile on a core 1a, and a shaft 2 secured to the core 1a and serving as a rotary shaft for the platen roller 1. A pair of circular projecting ribs 1d are provided on the opposite end faces of the core 1a and are partially cut away toward the center of rotation of the platen roller 1 to form recessed portions 1b in an opposing relationship to each other. A force fitting hole 1c having a fixed depth is provided on a face of each of the recessed portions 1b. A pair of stoppers 4 for a record paper positioning member which is securely mounted in the force fitting holes 1c extend outwardly from an outer periphery of the platen roller 1, and such stoppers 4 are mounted in an opposing relationship to each other on the opposite end faces of the platen roller 1. A fixing arm 5 of a record paper fixing member for fixing an end portion of record paper 3 having a sufficient width to allow the record paper 3 to contact with the pair of stoppers 4 against the outer periphery of the platen roller 1 along the direction of the shaft 2 has formed on the opposite end faces thereof a pair of grooves 5a for fitting with the shaft 2 and a pair of projected portions 5b for fitting with the recessed portions 1b. A pair of springs 6 are each mounted in a substantially U-shape around the shaft 2 on the fixing arm 5. The fixing arm 5 is mounted for movement in a radial direction of the platen roller 1 as seen in Fig. 3. A pair of steps 2a for positioning the fixing arm 5 in its thrust direction are formed on the opposite ends of the shaft 2. Subsequently, construction of the thermal transfer recording apparatus of the embodiment of the present invention will be described with reference to Figs. 1 and 6 to 9. Fig. 1 is a schematic plan view of the thermal transfer recording apparatus; Fig. 6 is a front elevational view of a gear block serving as a driving source for a rotary system; Fig. 7 is a sectional view taken along line B-B of Fig. 1 and is a front elevational view showing a driving system of the apparatus; Fig. 8 is a partial detailed view of a driving system gear; and Fig. 9 is a schematic view taken along line A-A of Fig. 1 and is a schematic front elevational view of the apparatus. Referring to Fig. 1, the platen roller 1 is supported for rotation around an axis of the shaft 2 between a pair of chasses 7a and 7b appearing at an upper portion of Fig. 1, and a platen gear 8 appearing at a left portion of Fig. 1 for transmitting rotation is fixed to an end of the shaft 2 and has a two-stage construction of a large gear 8a and a small gear 8b. sub chassis 10 is mounted on the chassis 7b, and a motor 9 serving as a driving source for a rotary system is secured to the sub chassis 10 using a pair of pawl portions 10a shown in Fig. 6. A slit plate 11 having slits equidistantly formed thereon is securely mounted on a rotary shaft of the motor 9. Thus, a driving circuit not shown controls the rotational speed of the motor 9 in response to a sensor 13 mounted on the sub chassis 10. The slit plate 11 and a worm gear 12 are connected to receive turning force of the motor 9. Shafts 14, 15, 16, 17, 18 and 19 are implanted on the sub chassis 10, and a worm wheel gear 20, a first intermediate gear 21, an ink paper takeup reel receiver 22, an ink paper supplying reel receiver 23, a change-over gear 24 and a locking arm 26 are mounted for rotation or pivotal motion on the shafts 14 to 19, respectively. The worm wheel gear 20 is constituted from a three-stage gear of a large gear 20a, a middle gear 20b and a small gear 20c, and the large gear 20a is held in engagement with the worm gear 12 while the middle gear 20b is held in engagement with the first intermediate gear 21 to transmit rotational driving force of the work wheel gear 20 to the ink paper takeup reel receiver 22. The small gear 20c is engageable with the change-over gear 24 to transmit rotation thereof to the latter. A view of detailed construction of the change-over gear 24 is shown in Fig. 8. Referring to Fig. 8, a slide gear 25 fitted on the change-over gear 24 with a spring 28 interposed therebetween has the same center of rotation as the change-over gear 24 and is mounted for sliding movement in an axial direction of and for normal integral rotation with the change-over gear 24. The slide gear 25 is constituted from a two-stage gear of a large gear 25a and a small gear 25b which are engageable with the large gear 8a and small gear 8b of the platen gear 8, respectively. An arresting member 27 for the slide gear 25 which is urged by the spring 28 is securely mounted at an end portion of the shaft 18. The ink paper takeup reel receiver 22 appearing at an upper portion of Fig. 7 is constituted such that it is driven by constant frictional rotational torque which is produced by way of a slip mechanism (not shown) in the inside thereof from rotational driving force transmitted from the first intermediate gear 21. Further, three reflecting plates 29 for discriminating a direction of rotation of the ink paper takeup reel receiver 22 by means of a sensor are applied at large, middle and small pattern pitches to the ink paper winding reel receiver 22. The ink paper supplying reel receiver 23 appearing at a right portion of Fig. 7 is constituted such that fixed brake torque is produced from a slip mechanism not shown in the inside thereof, and a plurality of reflecting plates 30 for discriminating rotation of the ink paper supplying reel receiver 23 are applied in equal pitch patterns on the ink paper supplying reel receiver 23. Here, frictional torque of the ink paper supplying reel receiver 23 is set such that it has a lower value than frictional torque of the ink paper takeup reel receiver 22. A locking spring 31 extends between the sub chassis 10 and the locking arm 26 for engaging with a locking pawl 23a securely mounted on the ink paper supplying reel receiver 23 appearing at a right lower portion of Fig. 7. When the slide gear 25 appearing at a right middle portion of Fig. 1 is moved toward the change-over gear 24, the large gear 25a is engaged with a second intermediate gear 32 mounted for rotation on a shaft (not shown) implanted on the chassis 7b while the second intermediate gear 32 is engaged with a first stage gear 33a of a two-stage gear 33 provided in a similar manner. A pickup roller 34 appearing at a middle lower portion of Fig. 9 includes a shaft 34a around which a rubber member is formed fixedly such that it has an outer periphery of an uneven profile. The pickup roller 34 is supported for rotation between the chasses 7a and 7b, and a pulley gear 35 for obtaining rotational driving force is securely mounted at an end of the shaft 34a shown at a middle left portion in Fig. 1. A feed roller 36 appearing at a middle portion of Fig. 1 includes a shaft 36a around a central portion of which a cylindrical rubber roller 36b having a pair of projected portions at the opposite ends thereof is securely mounted by molding, and a pair of cylindrical rubber members 36c are securely mounted at the opposite ends of the rubber rollers 36b by molding. Further, a feed gear 37 for obtaining rotational driving is securely mounted with construction of a two-stage gear of a large gear 37a and a small gear 37b at an end of the shaft 36a which is supported for rotation between the chasses 7a and 7b, and a paper discharging gear 38 for transmitting driving force is securely mounted at the other end of the shaft 36a appearing at a middle portion of Fig. 9. A separating roller 39 includes a shaft 39a around which a rubber member for contacting with the cylindrical rubber member 36c of the feed roller 36 appearing at a middle portion of Fig. 1 is securely mounted in a cylindrical profile by molding. Though not shown here, the separating roller 39 is supported for movement to a position indicated by broken lines in Fig. 9 and also for rotation. A coupling 40 wherein fixed rotational torque acts by a slip mechanism in the inside appearing at a middle portion in Fig. 1 is provided at an end of the shaft 39a. The first stage gear 33a of the two-stage gear 33 appearing at a middle left portion of Fig. 1 is engaged with the pulley gear 35 which transmits rotational driving force by way of the coupling 40 and a rubber belt 41. The second stage gear 33b of the two stage gear 33 is engaged with the small gear 37b of the feed gear 37 to rotate the feed roller 36. It is to be noted that the large gear 37a of the feed gear 37 is engaged with the small gear 25b of the slide gear 25 when the slide gear 25 is moved toward the chassis 7b. The paper discharging gear 38 appearing at a middle portion of Fig. 9 is held in engagement with a spur gear 43a of a third intermediate gear 43 mounted for rotation on a shaft 42 appearing at a middle right portion of Fig. 1 implanted on the chassis 7a of Fig. 1. The third intermediate gear 43 is a two-stage gear constituted from the spur gear 43a and a bevel gear 43b. A worm gear 45 is connected such that rotation of a rotary shaft of a second motor 44 for changing over the operating position of the apparatus appearing at a right portion of Fig. 7 is transmitted thereto. The worm gear 45 is engaged with a large gear 46a of a speed reducing gear 46 mounted for rotation on a shaft not shown while a small gear 46b transmits driving force to a cam gear 47 which is provided for rotation on a shaft 49 implanted on the chassis 7b to determine the operating position of the apparatus. A small gear 47a is provided on the cam gear 47 and held in engagement with a rotary change-over switch 48. Here, the change-over switch 48 is connected to a driving circuit for the second motor 44 and is constituted such that rotation of the motor 44 which is driven in accordance with any operation mode may be stopped in response to a statement signal of a designated position. The second motor 44, speed reducing gear 46 and change-over switch 48 are mounted on a bracket not shown and installed on the chassis 7b. First and second grooves not shown are formed on a face of the cam gear 47, and a pin 50 for engaging with the first groove is implanted on an arm 51. The arm 51 is mounted for pivotal motion around a fulcrum 52 on the chassis 7b, and a pin 53 is implanted at a position of the arm 51 at which a movement of the pin 50 is magnified. The pin 53 is held in fitting engagement in an elongated hole 54a of a slider 54 for performing a changing over operation of the apparatus. The slider 54 is constructed for movement in the direction indicated by an arrow mark A in Fig. 7 on the chassis 7b by way of a pair of guide grooves 54b which fit with guide shafts 550 implanted on the chassis 7b. An uneven portion 54c for contacting with the cylindrical projected portion 26a of the locking arm 26 is formed on the slide 54 for pivoting the locking arm 26. Shafts 56 and 57 are implanted on the chassis 7b, and a change-over arm 55 and a platen locking arm 58 are mounted for pivotal motion on the shafts 56 and 57, respectively. An end of the change-over arm 55 is contacted with the slide gear 25 so that it can be pivoted toward the shaft 18. Meanwhile, the other end of the change-over arm 55 is contacted with an uneven portion 54d for the change-over arm provided on the slider 54 so that the change-over arm 55 can obtain a necessary amount of pivotal motion. An end of the platen locking arm 58 appearing at a right middle portion of Fig. 7 has a projected portion provided thereon for engaging with root portions between teeth of the large gear 8a and is urged toward the large gear 8a by a platen locking spring 100 extending between the platen locking arm 58 and the chassis 7b while the other end of the platen locking arm 58 has a cylindrical projected portion 58a provided thereon for contacting with an uneven portion 54e provided on the slider 54. A K arm 60 serving as driving means for the fixing arms 5 which is mounted for pivotal motion around the fulcrum 59 between the chasses 7b and 7a has a pin 61 implanted thereon for fitting with a pivoting hole 54f provided on the slider 54. An end 60a and the other end 60b of the K arm 60 appearing at a middle lower portion of Fig. 9 are constituted such that they are contacted, depending upon positions at which the fixing arms 5 are stopped, with the fixing arms 5 to cancel pressing force of the fixing arms 5. A pivot shaft 65b implanted on a head arm 66b extends through a driving arm 64 on which a head pin 63 for fitting with the second groove of the cam gear 47 appearing at a left portion of Fig. 1 is implanted to support the driving arm 64 for pivotal motion, and another pivot shaft 65a is implanted on the driving arm 64 appearing at a right upper portion of Fig. 1 and extends for rotation through the head arm 77a. The pivot shafts 65a and 65b are supported for rotation between the chasses 7a and 7b, and a thermal head 101 is secured to the head arms 66a and 66b by means of screws 67 and a heat radiating plate 69 is secured to the thermal head 101 by means of screws 67. Reference numeral 70 denotes a cooling fan for the thermal head 101, and the cooling fan 70 is secured between the chasses 7a and 7b by way of a bracket not shown. A head spring 68 for pressing the thermal head 101 with fixed force against the platen roller 1 extends between each of the head arms 66a and 66b and the driving arm 74. Meanwhile, in order to cancel the pressing force of the thermal head 101, a convex projected portion 200 of the driving arm 64 is contacted with hole portions provided in the head arms 66a and 66b. Reference numeral 71 denotes a light emitting element for emitting light of a fixed wavelength, and 72 a light receiving element for receiving such light, and the light emitting element 71 and light receiving element 72 are provided at an end of the thermal head 101 such that light may pass through ink paper 75 wound around a takeup reel 74 and a supply reel 75 in an ink paper cartridge 73. Here, the ink paper 76 has, though not shown, inks of three colors of yellow, magenta and cyan applied successively to a base film thereof, and light of the light emitting element 71 passes through the yellow and magenta, but the ink of the cyan is composed of components which do not pass light therethrough. After the ink paper cartridge 73 is mounted on the apparatus, the takeup reel 74 and supply reel 75 are engaged, through holes (not shown) perforated in the ink paper cartridge 73, with the ink paper takeup reel receiver 22 and ink paper supplying reel receiver 23 to couple for integral rotation to each other, respectively. Reference numerals 77 and 78 denote each a switch for detecting an outer profile of the ink paper cartridge 73, and the switches 77 and 78 effect determination of presence or absence of an ink paper cartridge in the apparatus, or in the case of the ink paper cartridge 73 wherein the ink paper 76 of a different characteristic is wound, the outer profile is modified partially such that it is detected by the switches 77 and 78 so that a controlling circuit not shown may select a printing condition conforming to the characteristic of the ink paper. Reference numerals 79 and 80 appearing at a left middle portion of Fig. 1 denote each a sensor for detecting a position of the platen roller 1, and the sensors 79 and 80 are provided on the platen gear 8. Reference numeral 81 appearing at a right lower portion of Fig. 9 denotes a supply side guide for guiding the ink paper cartridge 73 upon loading, and the supply side guide 81 has such a profile as to guide the record paper 3 along part of an outer periphery of the platen roller 1. Reference numeral 82 appearing at a lower middle portion of Fig. 9 denotes a transport guide, and a sensor 102 for discriminating whether or not the record paper 3 is transported thereto is mounted on the transport guide 82 forwardly of a position at which the record paper 3 and the stopper 4 are contacted with each other upon paper feeding. Reference numeral 83 appearing at a middle portion of Fig. 9 denotes a takeup side guide for the ink paper cartridge 73, and a discharging opening 83a which is used when the record paper 3 is discharged is provided in the takeup side guide 83. The takeup side guide 83 further has formed thereon a guide portion 83c for guiding the ink paper cartridge 73 upon supplying of the record paper 3 and another guide portion 83d for guiding the ink paper cartridge 73 when the record paper 3 is transported by the platen roller 1. Further, an engaging portion 83b for engaging with the takeup side guide 83 and fixing arm 5 when the fixing arm 5 is pushed up by the platen roller 1 upon discharging of the record paper 3 is provided on the takeup side guide 83. The supply side guide 81, transporting guide 82 and takeup side guide 83 are provided and secured between the chasses 7a and 7b. An upper side guide member 84 and a lower side guide member 85 for guiding discharged record paper (not shown) appearing at a left portion of Fig. 7 are provided in combination. A shaft 860 is implanted on the lower guide member 85, and a paper discharging pivotal arm 103 is mounted for pivotal motion on the shaft 860 and for contacting engagement with the slider 54. A torsion spring 99 is provided between the paper discharging arm 103 and the lower guide member 85 and urges the paper discharging arm 103 toward the slider 54. A pair of pivotal arms 86 and 87 for changing the direction of record paper (not shown) are fitted for pivotal motion in a hole 84a perforated in the upper side guide member 84 appearing at a lower portion of Fig. 1 and another hole (not shown) perforated in the lower guide member 85 in an opposing relationship to the hole 84a, respectively, between the upper guide member 84 and lower guide member 85 and further for engaging with gear portions 86a and 87a, respectively. A cylindrical portion 86b for contacting with the paper discharging pivotal arm 103 appearing at a left portion of Fig. 7 is provided on the one pivotal arm 86, and an arm spring 88 extends between the cylindrical portion 86b and a hooked portion 85a provided on the lower side guide member 85. A spring member 90 for applying contacting force to a roller 89 which is contacted with and rotated by the rubber roller 36b at the central portion of the feed roller 36 is secured to the upper side guide member 84 appearing at a lower portion of Fig. 1, and a shaft 91a of a discharging roller 91 for discharging record paper (not shown) from the apparatus is supported for rotation on the upper side guide member 84. A bevel gear 92 is securely mounted at an end of the shaft 91a and held in engagement with the bevel gear 43b of the first intermediate gear 84 to transmit rotational driving force changing the direction of axis of rotation by 90 degrees. An auxiliary roller 93 which is contacted with and rotated by the paper discharging roller 91 appearing at a left portion of Fig. 7 obtains contacting force from a leaf spring 94 provided on the lower side guide member 85. Reference numeral 95 denotes a sensor for detecting record paper 3 discharged between the upper and lower guide members 84 and 85, and the sensor 95 is mounted on the lower guide member 85. Reference numeral 96 appearing at a left portion of Fig. 9 denotes a tray for the record paper 3, 95 a switch for detecting presence or absence of the tray 96, and 98 a sensor for determining presence or absence, overlapping feeding and a kind of the record paper 3. Subsequently, operation of the embodiment of the present invention will be described. In order to perform a printing operation, an ink cartridge 73 and a record paper tray 96 shown in Fig. 9 are first loaded in position into the apparatus, whereupon the switches 77 and 78 disposed in the neighborhood of the ink paper cartridge 73 and the switch 97 appearing at a leftmost portion of Fig. 9 transmit each a signal of completion of loading to the controlling circuit not shown, and the apparatus enters a standby condition. Then, if a print button not shown is depressed, then the second motor 44 appearing at a right portion of Fig. 7 is rotated so that the cam gear 47 is rotated by way of the speed reducing gear 46. Then, after the change-over switch 48 is changed over to a position for a paper supply mode, the motor 44 is stopped. By such operation, the arm 51 appearing at a rightmost portion of Fig. 7 is pivoted in the leftward direction to move the slider 54. By such movement of the slider 54, the supply side reel receiver 23 is fixed by the locking pawl 23a and locking arm 26, and the platen gear large gear 8a appearing at a right portion of Fig. 7 and the platen locking arm 58 are engaged with and fixed by each other in order that the platen roller 1 may not be rotated when the record paper 3 is contacted with the stoppers 4 of Fig. 10. Meanwhile, when the change-over arm 55 is pivoted in the direction of an arrow mark in Fig. 8 to the broken line position, the large gear 25a of the slide gear 25 is engaged with the second intermediate gear 32 appearing at a central portion Fig. 7 while the small gear 25b of the slide gear 25 is not engaged with any gear. Consequently, the rotation transmitting system to the platen roller 1 is interrupted. In addition, the paper discharging pivotal arm 103 is pivoted in the direction of an arrow mark B by the slider 54 of Fig. 7, and the pivotal arms 86 and 87 shown at a lower portion of Fig. 1 are pivoted to the broken line positions by the urging of the arm spring 88 while the K arm 60 of Fig. 9 is pivoted in the counterclockwise direction until the fixing arm 5 and the end 60a of the K arm 60 are contacted with each other to move the fixing arm 5 away from the outer periphery of the platen roller 1. Meanwhile, though not shown, the K arm 60 is operated together with the slider 54 so that the record paper 3 in the tray 96 is pressed against the pickup roller 34 at a central portion of Fig. 1 only in a paper supply mode. In the paper supplying condition described so far, the motor 9 of Fig. 7 is rotated subsequently to guide the record paper 3 appearing at a mid portion of Fig. 9 toward a position between the outer periphery of the platen roller 1 and the fixing arm 5 by the transporting guide 82 to effect positioning of the record paper 3 with respect to the platen roller 1. The apparatus in this condition is shown in Fig. 9, and a detailed view of the fixing arm 5 and the record paper 3 then is shown in Fig. 10. Here, the discrimination whether or not the record paper 3 has been contacted with the stoppers 4 can be effected readily if the controlling circuit not shown for the motor 9 of Fig. 7 is driven if the time until the record paper 3 is contacted with the stoppers 4 after the sensor 102 appearing at a lower portion of Fig. 9 has detected the record paper 3 is taken into consideration. After the record paper 3 is contacted with the stoppers 4 in Fig. 10, the motor 9 of Fig. 7 is stopped while the second motor 44 at a rightmost portion of Fig. 7 is rotated. Consequently, the apparatus changes from the paper supply mode into an ink paper initializing mode similarly as in the operation described above. By the movement, the slider 54 is moved in the rightward direction of Fig. 7, and in the ink paper initializing mode, the locking arm 26 is pivoted to cancel the fixation of the supply reel receiver 23; the platen roller remains in a fixed condition similarly as in the paper supply mode described above; the slide gear 25 is operated similarly as in the paper supply mode described above; and the paper discharging pivotal arm 103 is released from contact with the slide 54 and the urging force of the torsion spring 99 overcomes the arm spring 88 to pivot the paper discharging pivotal arm 103 in the direction of c of Fig. 7 to pivot the pivotal arms 86 and 87 to positions of alternate long and short dash lines of Fig. 1; and the K arm 60 at a lower portion of Fig. 9 is pivoted to a position at which it does not contact with the fixing arm 5 to fix the record paper 3 on the outer periphery of the platen roller 1 with the fixing arm 5. Further, the driving arm 64 is pivoted by the second groove of the cam gear 47 appearing at a rightmost portion of Fig. 9 to lower the thermal head 101 to the broken line position of Fig. 9. If the motor 9 of Fig. 7 is rotated subsequently in the ink paper initializing mode condition described so far, since slip torque of the ink paper takeup reel receiver 22 at an upper portion of Fig. 9 is greater than brake torque of the ink paper supplying reel receiver 23, the ink paper 76 is wound up onto the takeup reel 74. Thereupon, as light of the light emitting element 71 is received by the light emitting element 72 by way of the ink paper 76, a boundary between a yellow portion and a cyan portion having different light transmission factors is detected to effect heading of a yellow portion for the first color. After such heading is completed, the motor 9 of Fig. 7 is stopped while the second motor 44 is rotated. Consequently, the apparatus changes from the ink paper initializing mode to a record paper transporting mode similarly to the operation described above. Thereupon, the slider 54 is moved, and in the record paper transporting mode, the locking arm 26 at a right lower portion of Fig. 7 fixes the supplying reel receiver 23; the platen locking arm 58 cancels the fixation of the platen gear large gear 8a; and the large gear 25a of the slide gear 25 of Fig. 8 appearing at a left mid portion of Fig. 1 is engaged with the platen gear small gear 8b and second intermediate gear while the small gear 25b of the slide gear 25 is not engaged with any gear due to a relationship between the spring 28 and a portion 54d of the slider 54 with which the change-over arm 55 is contacted. The paper discharging pivotal arm 103 at a left portion of Fig. 7, the K arm 60 at a lower mid portion of the figure and the thermal head 101 at a right upper portion Fig. 7 are similar to those in the ink paper initializing mode described above. If the motor 9 of Fig. 7 is rotated subsequently in the record paper transporting mode condition described so far, then the platen roller 1 at a lower mid portion of Fig. 9 is rotated with the record paper 3 fixed thereto by the fixing arms 5, and if the sensor 80 at a left mid portion of Fig. 1 detects a detection portion not shown provided on the platen gear 8, then the motor 9 is stopped while the second motor 44 of Fig. 9 is rotated. Consequently, the apparatus changes over from the record paper transporting mode to a printing mode similarly to the operation described above. Thereupon, the slider 54 at a lower portion of Fig. 7 is moved, and in the printing mode, the fixation of the supplying reel receiver 23 is cancelled; the platen locking arm 58 is released similarly as in the record paper transporting mode described above; and the slide gear 25 is moved to a position shown in Fig. 8 due to a relationship between the spring 28 and the portion 54d of the slider 54 with which the change-over arm 55 is contacted, and the small gear 25b at a left portion of Fig. 1 is engaged with the platen gear large gear 8a and the feed gear large gear 37a while the large gear 25a is not engaged with any gear. The paper discharging pivotal arm 103 at a lower portion of Fig. 7 and the K arm 60 are similar as in the record paper transporting mode described above. The driving arm 64 is pivoted by the second groove of the cam gear 47 at a rightmost portion of Fig. 7, and the thermal head 101 of Fig. 11 presses the ink paper 76 and record paper 3 in an overlapping relationship against the platen roller 1. If the motor 9 of Fig. 7 is rotated subsequently in the printing mode condition described so far, then energization of the thermal head 101 of Fig. 9 is started simultaneously by the controlling circuit not shown, and a printing operation is performed and the condition of Fig. 11 is entered. Fig. 12 is a detailed view of the record paper 3 and fixing arm 5 then. Here, the energization pitch of the thermal head 101 is synchronized with a driving amount of the platen roller 1 as the sensor 13 detects the slit plate 11 securely mounted on the rotary shaft of the motor 9 of Fig. 7. In this instance, the ink paper 76 and record paper 3 of Fig. 9 are fed integrally by the platen roller 1, and the ink paper 76 after use is separated from the record paper 3 at an end portion of the thermal head 101 and is wound up onto the takeup reel 74 by the takeup reel receiver 22. It is to be noted that brake torque exerted by a click mechanism provided on the supplying reel receiver 23 is applied as back tension to the ink paper 76 to effect prevention of occurrence of wrinkles on the ink paper 76. Meanwhile, the record paper 3 is guided by the guide members 81, 82 and 83 so as to extend along the platen roller 1. After printing of a predetermined amount of the first color (yellow) is completed, energization of the thermal head 101 is stopped, but transportation of the record paper 3 and ink paper 76 by the pressing of the thermal head 101 continues while heading of a second color (magenta) is performed and separation of the record paper 3 and ink paper 76 after printing is effected. After the two operations are completed, the motor 9 is stopped while the second motor 44 is rotated. Consequently, the apparatus changes over from the printing mode to a record paper transporting mode similarly to the operation described above. After then, the third color (magenta) and a third color (cyan) are printed similarly as in the operation described above. After completion of printing of the third color, the platen roller 1 is rotated in the record paper transporting mode, and the motor 9 is stopped while the second motor 44 is rotated in response to the sensor 80 at a left portion of Fig. 1 similarly as in the operation described above. Consequently, the apparatus changes over from the record paper transporting mode to a record paper discharging mode similarly as in the operation described above. In this instance, the slider 54 at a lower portion of Fig. 7 is moved, and in the record paper discharging mode, the supplying reel receiver 23 is fixed by the locking arm 26; the platen locking arm 58 is released similarly as in the record paper transporting mode described above; and the slide gear 25 is engaged with the platen gear 8 in a similar condition as in the printing mode described above. The K arm 60 at a lower portion of Fig. 7 is pivoted by the pivotal arm 54f of the slider 54, and as the fixing arm 5 at a lower portion of Fig. 9 and an end 60b of the K arm 60 are contacted with each other, the fixing arm 5 is moved away from the outer periphery of the platen roller 1 to cancel the fixation of the record paper 3. In this instance, the projected portions 5b of the fixing arm 5 of Fig. 10 are removed from the recessed portions 1b of the platen roller 1 and moved to positions on the outer periphery of the projected ribs 1d. The paper discharging pivotal arm 103 at a lower portion of Fig. 7 and the thermal head 101 of Fig. 9 are similar as in the printing mode described above. Fig. 13 shows an operational view of the apparatus when pivotal motion of the platen roller proceeds until the fixing arm and the takeup side guide are contacted with each other, and Fig. 14 is an enlarged view of such contacting portions. If the motor 9 is rotated in the record paper discharging mode, the fixing arm 5 is contacted and engaged with the engaging portion 83b of the takeup side guide 83 as shown in Fig. 13, and the projected portions 5b of the fixing arm 5 of Fig. 14 are contacted with the outer periphery of the projected ribs 1d of the platen roller 1 so that the gap between the platen roller 1 and the fixing arm 5 is kept constant. The record paper 3 is thus transported to the discharging opening 83a of the takeup side guide by the platen roller 1 under pressing force of the thermal head 101. Further, the motor 9 of Fig. 1 is rotated to contact the record paper (not shown) with the rubber roller 36b at the central portion of the feed roller, and the motor 9 is stopped after the record paper is transported until it is caught by the roller 89 which is being rotated. Detection of the position of the record paper then can be effected readily by the driving circuit not shown if rotation of the slit plate 11 mounted on the motor 9 is detected by the sensor 13 of Fig. 7. Further, while the ink paper 76 at a right portion of Fig. 13 is fed together with the record paper 3, the length of the third color is determined such that a succeeding first color may not appear even by such feeding. Subsequently, the motor 44 of Fig. 7 is rotated to change over the apparatus from the record paper discharging mode to a record paper transporting mode. Thereupon, the slider 54 is moved, and the apparatus is put into a similar condition as in the record paper transporting mode described above. If the motor 9 is rotated in this condition, the record paper is transported by the rubber roller 36b at the central portion of the feed roller of Fig. 1 and the roller 89 and is discharged between the upper and lower guide members 84 and 85. Thereupon, since the pivotal arms 86 and 87 are positioned at the positions indicated by alternate long and short dash lines in Fig. 1, they will not be contacted with the record paper. Further, when the platen roller 1 makes one rotation in Fig. 14, the projected portions 5b of the fixing arm 5 are fitted with the recessed portions 1b of the platen roller 1 by the urging force of the springs (not shown) and press against the platen roller 1. When a fixed interval of time passes after the sensor 95 has detected the record paper (not shown) in Fig. 13, the motor 9 is stopped. Thereupon, a rear end of the record paper has been discharged thoroughly to a position between the upper and lower guide members 84 and 85, and the position of the platen roller 1 of Fig. 1 is stopped at a position of the paper supplying mode when the detection portion of the platen gear 8a is detected by the sensor 79. Subsequently, the second motor 44 is rotated so that the apparatus is moved from the record paper transporting mode to a standby mode similarly to the operation described above. Thereupon, the slider 54 of Fig. 7 is moved, and in the standby mode, the supplying reel receiver 23 is fixed by the locking arm 26; the platen roller 1 is fixed by the platen locking arm 58; and the slide gear 25 of Fig. 8 is moved to the same position as in the paper supplying mode, in short, the broken line position of Fig. 8; the K arm 60 at a lower portion of Fig. 7 is similar as in the record paper transporting port described above; and the thermal head 101 is moved up to the position shown in Fig. 9. The paper discharging pivotal arm 103 is contacted with the slider 54 to pivot the latter in the direction of B of Fig. 7 thereby to pivot the pivotal arms 86 and 87 to the broken line positions shown in Fig. 1 similarly as in the ink paper initializing mode described above. The record paper (not shown) between the upper and lower guide members 84 and 85 is pressed against the discharging roller 91 by the pivotal arms 86 and 87 of Fig. 1. If the motor 9 is rotated subsequently in the standby mode described so far, then the record paper is transported by the discharging roller 91 and auxiliary roller 93 and discharged outside the apparatus. In this instance, after a fixed interval of time after the sensor 95 which is watching the record paper detects that the record paper has disappeared, the motor 9 is stopped, thereby ending all operations. As described so far, according to the present invention, when record paper is supplied, turning power to the platen roller is interrupted, and further, pivotal motion of the platen roller is prevented. Consequently, the record paper can be transported stably to the record paper fixing mechanism section on the outer periphery of the platen roller using the motor for the rotational driving of the platen roller. Accordingly, an inexpensive thermal transfer recording apparatus can be provided which can print with a high degree of accuracy with a small number of mechanical parts and circuit parts without the necessity of a motor for the exclusive use for supplying and discharging of paper or the like.

Claims: A thermal transfer recording apparatus comprising: a platen roller (1) having a clamping mechanism for clamping a recording paper (3); means for transporting the recording paper to said clamping mechanism; a thermal head (101); and a motor (9); wherein the recording paper and ink paper (76) positioned on the recording paper clamped on said platen roller are heated from above the ink paper by said thermal head to effect recording on the recording paper; characterized in that said thermal transfer recording apparatus further comprises: platen roller locking means (58) for preventing a rotation of said platen roller (1); and power transmitting means for transmitting a torque of said motor (9); in that said power transmitting means has a first position at which no torque of said motor (9) is applied to said platen roller (1), while said means for transporting the recording paper is driven by said motor (9), and a second position at which the torque of said motor (9) is applied to said platen roller (1) while no torque of said motor (9) is applied to said means for transporting the recording paper; and in that said power transmitting means is moved to said first position and said platen roller locking means prevents the rotation of said platen roller (1) when the recording paper is to be transported to said clamping mechanism. A thermal transfer recording apparatus according to claim 1, characterized in that said platen roller locking means is constituted such that it prevents rotation of a driving gear secured to a shaft of said platen roller.

Inventors: NARUI YOUICHI, OKUNOMIYA SEIJI, OZAWA NAOHIRO NO HITACHI HACHI, TAKADA MASAMI, NARUI, YOUICHI, OKUNOMIYA, SEIJI, OZAWA, NAOHIRO, NO. 546 HITACHI HACHIMANYAMA APT., TAKADA, MASAMI
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1991
Main classification: B41J13
IPC codes: B41J13, B41J11