US20050146090A1 - Drive transmission mechanism and drive transmission mechanism for printer apparatus - Google Patents
Drive transmission mechanism and drive transmission mechanism for printer apparatus Download PDFInfo
- Publication number
- US20050146090A1 US20050146090A1 US11/029,467 US2946705A US2005146090A1 US 20050146090 A1 US20050146090 A1 US 20050146090A1 US 2946705 A US2946705 A US 2946705A US 2005146090 A1 US2005146090 A1 US 2005146090A1
- Authority
- US
- United States
- Prior art keywords
- gear
- diameter
- intermediate gear
- drive transmission
- conveying roller
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H5/00—Feeding articles separated from piles; Feeding articles to machines
- B65H5/06—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2401/00—Materials used for the handling apparatus or parts thereof; Properties thereof
- B65H2401/10—Materials
- B65H2401/11—Polymer compositions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2403/00—Power transmission; Driving means
- B65H2403/40—Toothed gearings
- B65H2403/42—Spur gearing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2701/00—Handled material; Storage means
- B65H2701/10—Handled articles or webs
- B65H2701/18—Form of handled article or web
- B65H2701/184—Wound packages
- B65H2701/1849—Wound packages in cartridge or similar packaging device
Definitions
- the present invention relates to a drive transmission mechanism, and to a drive transmission mechanism for a printer apparatus. More particularly, the invention relates to a drive transmission mechanism having plural gears, and to a drive transmission mechanism for a printer apparatus.
- JP-A-5-014787 discloses a printer apparatus provided with intermediate gears formed between a driving-side gear and a platen-roller-side gear by combining large and small, two gears, which are eccentric to a similar degree, with each other so that the directions of eccentricity thereof are opposite to each other on either side of a shaft thereof.
- the structure disclosed in JP-A-5-014787 reduces unevenness in the rotational speed thereof by disposing the large and small, two gears so that the unevennesses in the rotational speed due to the eccentricity each of these gears are cancelled out each other.
- FIG. 16 is a perspective view showing a conventional thermal transfer printer.
- FIGS. 17 to 19 are views showing a drive transmission mechanism of the conventional thermal transfer printer shown in FIG. 16 .
- the structure of the conventional thermal printer 100 is described hereinbelow by referring to FIGS. 16 to 19 .
- the conventional thermal printer 100 has a metallic frame 110 , a thermal transfer film accommodating member 111 , a sheet feeding roller 112 , a motor bracket 114 to which a motor 113 is attached, a film take-up member 115 , a sheet feeding roller gear 116 , plural intermediate gears 117 , a metallic conveying roller 120 , a resin conveying roller gear 130 connected to an end portion of the conveying roller 120 , and a resin intermediate gear 140 for rotating the conveying roller gear 130 . Further, as shown in FIGS.
- the conventional thermal transfer printer 100 has a resin drive transmission gear 150 , which is connected to a drive shaft 113 a of the motor 113 , for rotating the intermediate gear 140 , and an intermediate gear support shaft 160 rotatably supporting the intermediate gear 140 .
- the frame 110 is U-shaped.
- the thermal transfer film accommodating member 111 and the sheet feeding roller 112 are disposed on the inner surface side of the frame 110 .
- the motor 113 transmits a driving force to the drive transmission gear 150 through the drive shaft 113 a of the motor 113 .
- the motor bracket 114 is mounted on the outer surface of the frame 110 .
- the film take-up member 115 , the sheet feeding roller gear 116 , and the plural intermediate gears 117 are placed between the frame 110 and the motor bracket 114 . These plural intermediate gears 117 are placed so that the film take-up member 115 and the sheet feeding roller gear 116 can be driven by the single motor 113 .
- the conveying roller 120 is disposed under the thermal transfer film accommodating member 111 on the inner surface side of the frame 110 , and rotatably mounted on the frame 110 by a bearing 118 .
- a D-cut part 121 is formed in an end portion of this conveying roller 120 by performing a cutting work operation or the like.
- a D-shaped through hole 131 through which the D-cut part 121 of the conveying roller 120 is inserted, is formed in the conveying roller gear 130 .
- the intermediate gear 140 has a circular shaft insertion hole 141 .
- the intermediate gear 140 includes a small-diameter intermediate gear portion 142 , which meshes with the conveying roller gear 130 , and a large-diameter intermediate gear portion 143 that meshes with the drive transmission gear 150 and that has a diameter, which is larger than that of the small diameter intermediate gear portion 142 .
- the intermediate gear supporting shaft 160 includes an attaching portion 161 fixedly attached to the frame 110 by performing a caulking operation or the like.
- the intermediate gear supporting shaft 160 has a circular shape, which is substantially the same as that of the shaft insertion hole 141 .
- a drive transmission operation of the conventional thermal transfer printer 100 is described hereinbelow by referring to FIG. 17 .
- a driving force of the motor 113 (see FIG. 16 ) is transmitted to the drive transmission gear 150 through the drive shaft 113 a of the motor 113 .
- the drive transmission gear 150 rotates in the direction of an arrow M shown in FIG. 17 .
- the driving force of the drive transmission gear 150 is transmitted to the large-diameter intermediate gear portion 143 of the intermediate gears 140 .
- the large-diameter intermediate gear portion 143 and the small-diameter intermediate gear portion 142 rotate in the direction of an arrow N shown in FIG. 17 .
- the driving force of the small-diameter intermediate gear portion 142 is transmitted to the conveying roller gear 130 .
- the conveying roller gear 130 rotates in the direction of an arrow O shown in FIG. 17 . Consequently, the driving force is transmitted to the conveying roller 120 through the D-cut part 121 of the conveying roller 120 , which is inserted into the D-shaped through hole 131 of the conveying roller gear 130 .
- the conveying roller 120 rotates.
- At least one of the conveying roller gear 130 , the small-diameter intermediate gear portion 142 , the large-diameter intermediate gear portion 143 , and the drive transmission gear 150 may be eccentric due to manufacturing errors of the device, to abrasion caused after use of the device, and to thermal deformation thereof.
- this conventional printer has a problem in that it is difficult to rotate the conveying roller gear 130 (or the conveying roller 120 ) at a constant rotational speed.
- JP-A-5-014787 is enabled to reduce unevenness in the rotational speed of a platen-roller-side gear in a case where an eccentric gear is used in a manufacturing stage (a stage in which the device is not used yet). Consequently, this conventional printer has a problem in that it is difficult to reduce the rotational speed of the platen-roller-side gear in a case where the gear becomes eccentric during the device is used.
- JP-A-10-123785 discloses an image forming apparatus provided with annular stopper members, which have a reference pitch circle diameter being equal to those of a swinging gear and a transfer roller gear and are coaxially connected to the swinging gear and the transfer roller gear, in a drive transmission structure in which a driving force from a photoconductive drum gear is transmitted to a transfer roller gear (or a conveying roller gear) through the swinging gear pushed in the direction of the transfer roller gear.
- the structure disclosed in JP-A-10-123785 prevents occurrences of unevenness in the rotational speed of the transfer roller by keeping the distance between the swinging gear and the transfer roller gear at a constant value through the use of the stopper members even when the distance between the centers of the photoconductive drum and the transfer roller changes.
- JP-A-10-123785 has a problem in that because a coupler, the spring and the idler gear are needed for enabling the swinging gear, which is used for transmitting the driving force from the photosensitive drum gear to the transfer roller gear (or the conveying roller gear), to swing, the number of components increases for that. Also, this conventional structure has a problem in that because annular stopper members each having a reference pitch circle diameter, which is equal to those of the swinging gear and the transfer roller gear, are separately provided therein, the number of components increases in this regard. Additionally, this conventional structure has a problem in that because no stopper members are provided between the idler gear and the swinging gear and between the idler gear and the photosensitive drum gear, unevenness in the rotation is caused therebetween.
- an object of the invention is to provide a drive transmission mechanism for a printer apparatus or the like, which is enabled to rotate a gear, which transmits a driving force, at a constant rotational speed without increasing the number of components.
- a drive transmission mechanism for a printer apparatus which has a metallic conveying roller for conveying sheets, a resin conveying roller gear connected to one end portion of the conveying roller, a resin intermediate gear, provided with a shaft insertion hole, for rotating the conveying roller, a resin drive transmission gear, mounted on a drive shaft of a motor, for rotating the intermediate gear as the motor is driven, and an intermediate gear supporting shaft for rotatably supporting the shaft insertion hole of the intermediate gear.
- the intermediate gear includes a first-side intermediate gear portion meshed with the conveying roller gear, and also includes a second-side intermediate portion meshed with the drive transmission gear.
- the intermediate gear is disposed in a position, in which the intermediate gear is caused by a load of the conveying roller to bite into the conveying roller gear and the drive transmission gear, when the gears are driven.
- the resin conveying roller gear includes a conveying roller gear circular portion that is provided integrally with the conveying roller gear and that has a diameter being substantially equal to a reference pitch circle diameter of the conveying roller gear.
- the resin drive transmission gear includes a drive transmission gear circular portion that is provided integrally with the drive transmission gear and that has a diameter being substantially equal to a reference pitch circle diameter of the drive transmission gear.
- the resin intermediate gear further includes a first-side intermediate gear circular portion, which is provided integrally with the drive transmission gear and has a diameter being substantially equal to a reference pitch circle diameter of the first-side intermediate gear portion, and also includes a second-side intermediate gear circular portion that is provided integrally with the intermediate gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second-side intermediate gear portion.
- the intermediate gear supporting shaft is mounted in the shaft insertion hole of the intermediate gear in such a way as to provide a predetermined fitting clearance between the intermediate gear supporting shaft and the shaft insertion hole.
- the conveying roller gear circular portion is disposed in such a way as to be in contact with the first-side intermediate gear circular portion when the gears are driven.
- the drive transmission gear circular portion is disposed in such a manner as to be in contact with the second-side intermediate gear circular portion when the gears are driven.
- the conveying roller gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the conveying roller gear is provided at the conveying roller gear.
- the first-side intermediate gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the first-side intermediate gear portion of the intermediate gear is provided at the first-side intermediate gear portion of the intermediate gear for rotating the conveying roller gear.
- the conveying roller gear and the first-side intermediate gear portion of the intermediate gear can be meshed with each other so that a conveying-roller-gear-side part, whose diameter is equal to the reference pitch circle diameter the conveying roller gear, is in contact with a first-side-intermediate-gear-portion-side part, whose diameter is equal to the reference pitch circle diameter of the first-side intermediate gear portion.
- a conveying-roller-gear-side part whose diameter is equal to the reference pitch circle diameter the conveying roller gear
- a first-side-intermediate-gear-portion-side part whose diameter is equal to the reference pitch circle diameter of the first-side intermediate gear portion.
- the second-side intermediate gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the second-side intermediate gear portion of the intermediate gear is provided at the second-side intermediate gear portion of the intermediate gear.
- the drive transmission gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the drive transmission gear is provided at the drive transmission gear for rotating the intermediate gear.
- the second-side intermediate gear portion of the intermediate gear and the drive transmission gear can be meshed with each other so that a second-side-intermediate-gear-portion-side part, whose diameter is equal to the reference pitch circle diameter of the second-side intermediate gear portion, is in contact with a drive-transmission-gear-side part, whose diameter is equal to the reference pitch circle diameter of the drive transmission gear.
- a second-side-intermediate-gear-portion-side part whose diameter is equal to the reference pitch circle diameter of the second-side intermediate gear portion
- a drive-transmission-gear-side part whose diameter is equal to the reference pitch circle diameter of the drive transmission gear.
- the conveying roller gear circular portion is provided integrally with the conveying roller gear, while the first-side intermediate gear circular portion is provided integrally with the first-side intermediate gear portion of the intermediate gear.
- the conveying roller gear circular portion and the first-side intermediate gear circular portion are provided in the mechanism, the number of components does not increase. Consequently, each of the conveying roller gear and the intermediate gear can be rotated at a constant rotational speed without increasing the number of components.
- the second-side intermediate gear circular portion is provided integrally with the second-side intermediate gear portion of the intermediate gear, while the drive transmission gear circular portion is provided integrally with the drive transmission gear.
- the intermediate gear supporting shaft is mounted in the shaft insertion hole of the intermediate gear in such a way as to provide a predetermined fitting clearance between the intermediate gear supporting shaft and the shaft insertion hole.
- the conveying roller gear circular portion can surely be in contact with the second-side intermediate gear circular portion, while the first-side intermediate gear circular potion can surely be in contact with the drive transmission gear circular portion. Consequently, without separately providing a mechanism for swinging (or moving) the intermediate gear in the transmission mechanism, the conveying roller gear can surely be meshed with the intermediate gear, while the intermediate gear can surely be meshed with the drive transmission gear so that a conveying-roller-gear-side part, whose diameter is equal to the reference pitch circle diameter of the conveying roller gear, is in contact with an intermediate-gear-side part, whose diameter is equal to the reference pitch circle diameter of the intermediate gear, and that the intermediate-gear-side part, whose diameter is equal to the reference pitch circle diameter of the intermediate gear, is in contact with a drive-transmission-gear-side part, whose diameter is equal to the reference pitch circle diameter of the drive transmission gear.
- correction for unevenness in the rotation is performed on the engagement between the drive transmission gear and the intermediate gear, in addition to the engagement between the intermediate gear and the conveying roller gear.
- the unevenness in the rotation which is caused at the drive transmission gear, is corrected at two places.
- the conveying roller gear can more surely be rotated at a constant rotational speed.
- a drive transmission mechanism that includes a first gear and a second gear having a second first-side gear portion for rotating the first gear.
- the first gear includes a first circular portion that is provided integrally with the first gear and that has a diameter being substantially equal to a reference pitch circle diameter of the first gear.
- the second gear includes a second first-side circular portion that is provided integrally with the second first-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second first-side gear portion.
- the first circular portion is disposed in such a way as to be in contact with the second first-side circular portion when the gears are driven.
- the first circular portion having a diameter being substantially equal to the reference pitch circle diameter of the first gear is provided on the first gear.
- the second first-side circular portion having a diameter being substantially equal to the reference pitch circle diameter of the second first-side gear portion is provided at the second first-side gear portion for rotating the first gear.
- the first gear and the second first-side gear portion of the second gear can be meshed with each other so that a first-gear-side part, whose diameter is equal to the reference pitch circle diameter of the first gear, is in contact with a second-first-side-gear-portion-side part, whose diameter is equal to the reference pitch circle diameter of the second first-side gear portion.
- each of the first gear and the second gear can be rotated at a constant rotational speed without causing unevenness in the rotation thereof.
- first circular potion is provided integrally with the first gear and where second first-side circular portion is provided integrally with the second first-side gear portion of the second gear to thereby provide the first circular portion and the second first-side circular portion in the mechanism, the number of components does not increase. Consequently, each of the first gear and the second gear can be rotated at a constant rotational speed without increasing the number of components.
- the drive transmission mechanism is adapted so that the second gear has a shaft insertion hole, and further includes a second gear supporting shaft mounted in such a manner as to rotatably support the shaft insertion hole and as to provide a predetermined fitting clearance between the second gear supporting shaft and the shaft insertion hole.
- the second gear can easily be moved in such a way as to bite into the first gear.
- the first circular portion and the second first-side circular portion can surely be in contact with each other.
- the first gear and the second gear can mesh with each other, without separately being provided with a mechanism for swinging (or moving), so that a first-gear-side part, whose diameter is equal to a reference pitch circle diameter of the first gear, is in contact with a second-gear-side part, whose diameter is equal to a reference pitch circle diameter of the second gear.
- the drive transmission mechanism further includes a third gear for rotating the second gear.
- the second gear further includes a second second-side gear portion meshed with the third gear, and also includes a second second-side circular portion that is provided integrally with the second second-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second second-side gear portion.
- the third gear includes a third circular portion that is provided integrally with the third gear and that has a diameter being substantially equal to a reference pitch circle diameter of the third gear.
- the second second-side circular portion is disposed in such a manner as to be in contact with the third circular portion when the gears are driven.
- the third gear and the second second-side gear portion of the second gear can be meshed with each other so that a third-gear-side part, whose diameter is equal to a reference pitch circle diameter of the third gear, is in contact with a second-second-side-gear-portion-side part, whose diameter is equal to a reference pitch circle diameter of the second second-side gear portion. Consequently, even when at least one of the third gear and the second gear is eccentric, each of the third gear and the second gear can be rotated at a constant rotational speed without causing unevenness in the rotation thereof.
- the third circular portion is provided integrally with the third gear and where the second second-side circular portion are provided integrally with the second second-side gear portion of the second gear to thereby provide the third circular portion and the second second-circular portion in the mechanism, the number of components does not increase. Consequently, the third gear and the second second-side gear portion can be rotated at a constant rotational speed without increasing the number of components. Moreover, unevenness in the rotation, which occurs at the upstream side of driving-force transmission from the third gear, can be corrected at two places by providing the third circular portion at the third gear for rotating the second gear and also providing the second second-side circular portion at the second second-side gear portion included in the second gear. Thus, as compared with a case where such unevenness in the rotation is corrected at one place, the first gear can more surely be rotated at a constant rotational speed.
- a printer apparatus may include at least one of the drive transmission mechanisms according to the second aspect of the invention.
- the gear included in the apparatus can be rotated at a constant rotational speed without increasing the number of components and without causing unevenness in the rotation thereof. Consequently, the apparatus of the invention can obtain an advantage of reducing unevenness in printing images on sheets, without increasing the number of components.
- FIG. 1 is a perspective view illustrating a thermal transfer printer according to a first embodiment of the invention
- FIG. 2 is a side view illustrating a drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown in FIG. 1 ;
- FIG. 3 is a top view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown in FIG. 1 ;
- FIG. 4 is a cross-sectional view taken along line 200 - 200 in FIG. 2 ;
- FIG. 5 is a side view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown in FIG. 2 , at the time of driving the printer;
- FIG. 6 is a top view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown in FIG. 3 , at the time of driving the printer;
- FIG. 7 is a cross-sectional view taken along line 300 - 300 in FIG. 5 ;
- FIG. 8 is a cross-sectional view taken along line 400 - 400 in FIG. 5 ;
- FIG. 9 is a side view illustrating a drive transmission mechanism of a thermal transfer printer according to a second embodiment of the invention.
- FIG. 10 is a top view illustrating the drive transmission mechanism of a thermal transfer printer according to the second embodiment of the invention.
- FIG. 11 is a cross-sectional view taken along line 500 - 500 in FIG. 9 ;
- FIG. 12 is a side view illustrating the drive transmission mechanism of the thermal transfer printer according to the second embodiment of the invention, which is shown in FIG. 9 , at the time of driving the printer;
- FIG. 13 is a top view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown in FIG. 10 , at the time of driving the printer;
- FIG. 14 is a cross-sectional view taken along line 600 - 600 in FIG. 9 ;
- FIG. 15 is a cross-sectional view taken along line 700 - 700 in FIG. 9 ;
- FIG. 16 is a perspective view illustrating a conventional thermal transfer printer
- FIG. 17 is a side view illustrating a drive transmission mechanism of the conventional thermal transfer printer shown in FIG. 16 ;
- FIG. 18 is a top view illustrating the drive transmission mechanism of the conventional thermal transfer printer shown in FIG. 16 ;
- FIG. 19 is a cross-sectional view taken along line 800 - 800 in FIG. 17 .
- FIG. 1 is a perspective view illustrating a thermal transfer printer according to a first embodiment.
- FIGS. 2 to 4 are views illustrating the thermal transfer printer according to the first embodiment of the invention. First, the structure of a thermal transfer printer 1 according to the first embodiment of the invention is described hereinbelow by referring to FIGS. 1 to 4 .
- the thermal transfer printer 1 has a metallic frame 10 , a thermal transfer film accommodating member 11 , a sheet feeding roller 12 , a motor bracket 14 to which a motor 13 is attached, a film take-up member 15 , a sheet feeding roller gear 16 , plural intermediate gears 17 , a metallic conveying roller 20 , a resin conveying roller gear 30 connected to an end portion of the conveying roller 20 , and a resin intermediate gear 40 for rotating the conveying roller gear 30 . Further, as shown in FIGS.
- the thermal transfer printer 1 has a resin drive transmission gear 50 , which is connected to a drive shaft 13 a of the motor 13 , for rotating the intermediate gear 40 , and an intermediate gear support shaft 60 rotatably supporting the intermediate gear 40 .
- the thermal transfer printer 1 is an example of the “printer apparatus” of the invention.
- the conveying roller gear 30 is an example of the “first gear” of the invention.
- the intermediate gear 40 is an example of the “second gear”.
- the drive transmission gear 50 is an example of the “third gear” of the invention.
- the intermediate gear supporting shaft 60 is an example of the “second gear supporting shaft” of the invention.
- the frame 10 is U-shaped.
- the thermal transfer film accommodating member 11 and the sheet feeding roller 12 are disposed on the inner surface side of the frame 10 .
- the motor 13 transmits a driving force to the drive transmission gear 50 through the drive shaft 13 a of the motor 13 .
- the motor bracket 14 is mounted on the outer surface of the frame 10 .
- the film take-up member 15 , the sheet feeding roller gear 16 , and the plural intermediate gears 17 are placed between the frame 10 and the motor bracket 14 . These plural intermediate gears 17 are placed so that the film take-up member 15 and the sheet feeding roller gear 16 can be driven by the single motor 13 . Further, as shown in FIGS.
- the conveying roller 20 is disposed under the thermal transfer film accommodating member 11 on the inner surface side of the frame 10 , and rotatably mounted on the frame 10 by a bearing 18 .
- a D-cut part 21 is formed in an end portion of this conveying roller 20 by performing a cutting work operation or the like.
- a D-shaped through hole 31 through which the D-cut part 21 of the conveying roller 20 is inserted, is formed in the conveying roller gear 30 .
- the intermediate gear 40 has a circular shaft insertion hole 41 .
- the intermediate gear 40 includes a small-diameter intermediate gear portion 42 , which meshes with the conveying roller gear 30 , and a large-diameter intermediate gear portion 43 that meshes with the drive transmission gear 50 and that has a diameter, which is larger than that of the small diameter intermediate gear portion 42 .
- the small-diameter intermediate gear portion 42 is an example of each of the “first-side intermediate gear portion” and the “second first-side gear portion”.
- the large-diameter intermediate gear portion 43 is an example of each of the “second-side intermediate gear portion” and the “second second-side gear portion”.
- the intermediate gear supporting shaft 60 includes an attaching portion 61 fixedly attached to the frame 10 by performing a caulking operation or the like.
- the intermediate gear supporting shaft 60 is configured in such a manner as to rotatably support a shaft insertion hole 41 of the intermediate gear 40 and as to provide a predetermined fitting clearance (about 0.2 mm in the first embodiment) between the shaft 60 and the shaft insertion hole 41 .
- a conveying roller gear circular portion 32 having a diameter, which is substantially equal to the reference pitch circle diameter of the conveying roller gear 30 , is formed integrally with the resin conveying roller gear 30 .
- the conveying roller gear circular portion 32 is an example of the “first circular portion”.
- the small-diameter intermediate gear circular portion 44 is an example of each of the “first-side intermediate gear circular portion” and the “second first-side circular portion”.
- a large-diameter intermediate gear circular portion 45 having a diameter, which is substantially equal to the reference pitch circle diameter of the large-diameter intermediate gear portion 43 is provided integrally with the large-diameter intermediate gear portion 43 .
- the large-diameter intermediate gear circular portion 45 is an example of each of the “second-side intermediate gear circular portion” and the “second second-side circular portion”.
- a drive transmission gear circular portion 51 having a diameter, which is substantially equal to the reference pitch circle diameter of the drive transmission gear 50 is provided integrally with the drive transmission gear 50 .
- the drive transmission gear circular portion 51 is an example of the “third circular portion”.
- the conveying roller gear circular portion 32 is disposed so that when the gears are driven, the conveying roller gear circular portion 32 is in contact with the small-diameter intermediate circular portion 44 .
- the drive transmission gear circular portion 51 is disposed so that when the gears are driven, the drive transmission gear circular portion 51 is in contact with the large-diameter intermediate gear circular portion 45 .
- FIGS. 5 to 8 are views illustrating the drive transmission mechanism at the time of driving the thermal transfer printer according to the first embodiment of the invention, which is shown in FIG. 1 .
- a drive transmission operation of the thermal transfer printer 1 according to the first embodiment of the invention is described hereinbelow by referring to FIGS. 2 to 8 .
- the conveying roller gear circular portion 32 and the small-diameter intermediate gear circular portion 44 are not in contact with each other.
- the drive transmission gear circular portion 51 and the large-diameter intermediate gear circular portion 45 are not in contact with each other.
- the motor 13 is energized in this state, a driving force of the motor 13 is transmitted to the drive transmission gear 50 through the drive shaft 13 a of the motor 13 .
- the drive transmission gear 50 rotates in the direction of an arrow A shown in FIG. 5 .
- the driving force of the drive transmission gear 50 is transmitted to the large-diameter intermediate gear portion 43 of the intermediate gear 40 .
- the large-diameter gear portion 43 and the small-diameter intermediate gear portion 44 rotate in the direction of an arrow B shown in FIG. 5 .
- a force pushing the large-diameter intermediate gear portion 43 in the direction of an arrow D shown in FIG. 5 which is caused due to the driving force transmitted from the drive transmission gear 50 , is exerted on the large-diameter intermediate gear portion 43 of the intermediate gear 40 .
- the driving force of the small-diameter intermediate gear portion 42 is transmitted to the conveying roller gear 30 .
- the conveying roller gear 30 rotates in the direction of an arrow C of FIG. 5 . Consequently, the driving force is transmitted to the conveying roller 20 through the D-cut part 21 of the conveying roller 20 , which is inserted into the D-shaped through hole 31 of the conveying roller gear 30 .
- the conveying roller 20 rotates.
- the conveying roller gear circular portion 32 having a diameter, which is substantially equal to the reference pitch circle diameter of the conveying roller gear 30 is provided on the conveying roller gear 30 .
- the small-diameter intermediate gear circular portion 44 having a diameter, which is substantially equal to the reference pitch circle diameter of the small-diameter intermediate gear portion 42 of the intermediate gear 40 is provided on the small-diameter intermediate gear portion 42 of the intermediate gear 40 , which rotates the conveying roller gear 30 .
- the conveying roller gear 30 and the small-diameter intermediate gear portion 42 of the intermediate gear 40 can be meshed with each other so that a part at the side of conveying roller gear 30 , which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of the small-diameter intermediate gear portion 42 , which has a diameter being equal to the reference pitch circle diameter thereof.
- each of the conveying roller gear 30 and the intermediate gear 40 can be rotated at a constant rotational speed without causing unevenness in the rotation thereof.
- the large-diameter intermediate gear circular portion 45 having a diameter, which is substantially equal to the reference pitch circle diameter of the large-diameter intermediate gear portion 43 of the intermediate gear 40 is provided on the large-diameter intermediate gear portion 43 of the intermediate gear 40 .
- the drive transmission gear circular portion 51 having a diameter, which is substantially equal to the reference pitch circle diameter of the drive transmission gear 50 is provided on the drive transmission gear 50 that rotates the intermediate gear 40 .
- the large-diameter intermediate gear portion 43 of the intermediate gear 40 and the drive transmission gear 50 can be meshed with each other so that a part at the side of the large-diameter intermediate gear portion 43 , which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of the drive transmission gear 50 , which has a diameter being equal to the reference pitch circle diameter thereof.
- each of the intermediate gear 40 and the drive transmission gear 50 can be rotated at a constant rotational speed without causing unevenness in the rotation thereof.
- the conveying roller gear circular portion 32 is provided integrally with the conveying roller gear 30
- the small-diameter intermediate gear circular portion 44 is provided integrally with the small-diameter intermediate gear portion 42 of the intermediate gear 40 .
- the large-diameter intermediate gear circular portion 45 is provided integrally with the large-diameter intermediate gear portion 42 of the intermediate gear 40
- the drive transmission gear circular portion 51 is provided integrally with the drive transmission gear 50 .
- the intermediate gear supporting shaft 60 is mounted in such a way as to provide the predetermined fitting clearance (about 0.2 mm) between the intermediate gear supporting shaft 60 and the shaft insertion hole 41 of the intermediate gear 40 .
- the intermediate gear 40 can easily be moved in such a manner as to bite into the conveying roller gear 30 and the drive transmission gear 50 . Consequently, the conveying roller gear circular portion 32 can reliably be in contact with the large-diameter intermediate gear circular portion 45 , while the small-diameter intermediate gear circular portion 44 can reliably be in contact with the drive transmission gear circular portion 51 .
- the conveying roller gear 30 can reliably be meshed with the intermediate gear 40 , without separately providing a mechanism for swinging (or moving) the intermediate gear 40 , so that a part at the side of the conveying roller gear 30 , which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of the intermediate gear 40 , which has a diameter being equal to the reference pitch circle diameter thereof.
- the drive transmission gear 50 can reliably be meshed with the intermediate gear 40 , without separately providing a mechanism for swinging (or moving) the intermediate gear 40 , so that a part at the side of the drive transmission 50 , which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of the intermediate gear 40 , which has a diameter being equal to the reference pitch circle diameter thereof.
- correction for unevenness in the rotation is performed on the engagement between the drive transmission gear 50 and the intermediate gear 40 , in addition to the engagement between the intermediate gear 40 and the conveying roller gear 30 .
- the unevenness in the rotation, which is caused at the drive transmission gear 50 is corrected at two places.
- this embodiment can more surely rotate the conveying roller gear 30 at a constant rotational speed.
- FIGS. 9 to 11 are views illustrating a drive transmission mechanism of the thermal transfer printer according to a second embodiment of the invention.
- this second embodiment has a configuration in which a convex annular portion 41 a is provided in a shaft insertion hole 41 of an intermediate gear 40 a and which constituents respectively corresponding to the large-diameter intermediate gear circular portion 45 of the intermediate gear 40 and the drive transmission gear circular portion 51 of the drive transmission gear 50 of the thermal transfer printer according to the first embodiment of the invention illustrated in FIGS. 2 to 8 are omitted.
- the remaining constituents of the second embodiment other than the intermediate gear 40 a and the drive transmission gear 50 a are similar to those of the first embodiment.
- the convex annular portion 41 a of the intermediate gear 40 a is formed on a part, which is provided at the side of the frame 10 , in the shaft insertion hole 41 , as shown in FIG. 11 . Further, the annular portion 41 a of the intermediate gear 40 a is formed in such a way as to provide almost no fitting clearance between the annular portion 41 a and the outer periphery of the intermediate gear supporting shaft 60 .
- FIGS. 12 to 15 are views illustrating the drive transmission mechanism at the time of driving a thermal transfer printer according to the second embodiment of the invention.
- a drive transmission operation of the thermal transfer printer 70 according to the first embodiment of the invention is described hereinbelow by referring to FIGS. 9 to 15 .
- a conveying roller gear circular portion 32 and a small-diameter intermediate gear circular portion 44 are not in contact with each other.
- the motor 13 is energized in this state, a driving force of a motor 13 is transmitted to a drive transmission gear 50 a through a drive shaft 13 a of the motor 13 .
- the drive transmission gear 50 a rotates in the direction of an arrow G shown in FIG.
- the driving force of the small-diameter intermediate gear portion 42 is transmitted to the conveying roller gear 30 .
- the conveying roller gear 30 rotates in the direction of an arrow I of FIG. 12 . Consequently, the driving force is transmitted to the conveying roller 20 through a D-cut part 21 of the conveying roller 20 , which is inserted into a D-shaped through hole 31 of the conveying roller gear 30 .
- the conveying roller 20 rotates.
- the intermediate gear 40 a is rotatably supported by the intermediate gear supporting shaft 60 on the annular portion 41 a formed in the shaft insertion hole 41 of the intermediate gear 40 a in a state in which there is nearly no fitting clearance. Consequently, the intermediate gear 40 a is inclined and bites into the conveying roller gear 30 , as shown in FIG. 15 .
- the conveying roller gear circular portion 32 and the small-diameter gear circular portion 44 are brought into contact with each other and rotate.
- the invention is not limited thereto.
- the invention is not limited thereto.
- the invention may be widely applied to apparatuses each having a drive transmission mechanism other than the thermal transfer printer.
- the shaft insertion hole of the intermediate gear and the intermediate gear supporting shaft are circularly cross-sectionally formed in each of the first and second embodiments, the invention is not limited thereto.
- the shaft insertion hole of the intermediate gear and the intermediate gear supporting shaft may be formed into another shape including an elliptical shape.
- the description of the first and second embodiments have described examples in which the circular portions are provided on one or two sets of the gears meshed with one another when the driving force is transmitted, the invention is not limited thereto.
- the circular portions may be formed on the gears of three sets or more, which are meshed with one another when the driving force is transmitted.
- the circular portions may be provided on all the gears of the drive transmission mechanism.
Abstract
It is a drive transmission mechanism for a printer apparatus, which has a conveying roller gear connected to a conveying roller, an intermediate gear including a small-diameter intermediate gear portion for rotating the conveying roller gear, and an intermediate gear supporting shaft rotatably supporting a shaft insertion hole of the intermediate gear. In this mechanism, the conveying roller gear includes a conveying roller gear circular portion having a diameter that is substantially equal to the reference pitch circle diameter of the conveying roller gear. The intermediate gear includes a small-diameter intermediate gear circular portion having a diameter that is substantially equal to the reference pitch circle diameter of a small-diameter intermediate gear portion. Further, the intermediate supporting shaft is mounted therein in such a manner as to provide a predetermined fitting clearance between the intermediate supporting shaft and the shaft insertion hole.
Description
- 1. Field of the Invention
- The present invention relates to a drive transmission mechanism, and to a drive transmission mechanism for a printer apparatus. More particularly, the invention relates to a drive transmission mechanism having plural gears, and to a drive transmission mechanism for a printer apparatus.
- 2. Description of the Related Art
- Hitherto, there has been known a drive transmission mechanism for transmitting a driving force in a printer and so on by plural gears (see, for example, JP-A-5-014787).
- JP-A-5-014787 discloses a printer apparatus provided with intermediate gears formed between a driving-side gear and a platen-roller-side gear by combining large and small, two gears, which are eccentric to a similar degree, with each other so that the directions of eccentricity thereof are opposite to each other on either side of a shaft thereof. The structure disclosed in JP-A-5-014787 reduces unevenness in the rotational speed thereof by disposing the large and small, two gears so that the unevennesses in the rotational speed due to the eccentricity each of these gears are cancelled out each other.
-
FIG. 16 is a perspective view showing a conventional thermal transfer printer. FIGS. 17 to 19 are views showing a drive transmission mechanism of the conventional thermal transfer printer shown inFIG. 16 . The structure of the conventionalthermal printer 100 is described hereinbelow by referring to FIGS. 16 to 19. - As shown in
FIG. 16 , the conventionalthermal printer 100 has ametallic frame 110, a thermal transferfilm accommodating member 111, asheet feeding roller 112, amotor bracket 114 to which amotor 113 is attached, a film take-up member 115, a sheetfeeding roller gear 116, pluralintermediate gears 117, ametallic conveying roller 120, a resinconveying roller gear 130 connected to an end portion of theconveying roller 120, and a resinintermediate gear 140 for rotating theconveying roller gear 130. Further, as shown in FIGS. 17 to 19, the conventionalthermal transfer printer 100 has a resindrive transmission gear 150, which is connected to a drive shaft 113 a of themotor 113, for rotating theintermediate gear 140, and an intermediategear support shaft 160 rotatably supporting theintermediate gear 140. As shown inFIG. 16 , theframe 110 is U-shaped. The thermal transferfilm accommodating member 111 and thesheet feeding roller 112 are disposed on the inner surface side of theframe 110. Moreover, themotor 113 transmits a driving force to thedrive transmission gear 150 through the drive shaft 113 a of themotor 113. Furthermore, themotor bracket 114 is mounted on the outer surface of theframe 110. Additionally, the film take-upmember 115, the sheetfeeding roller gear 116, and the pluralintermediate gears 117 are placed between theframe 110 and themotor bracket 114. These pluralintermediate gears 117 are placed so that the film take-upmember 115 and the sheetfeeding roller gear 116 can be driven by thesingle motor 113. - Further, as shown in
FIGS. 16 and 19 , theconveying roller 120 is disposed under the thermal transferfilm accommodating member 111 on the inner surface side of theframe 110, and rotatably mounted on theframe 110 by abearing 118. As shown inFIGS. 17 and 19 , a D-cut part 121 is formed in an end portion of this conveyingroller 120 by performing a cutting work operation or the like. Furthermore, a D-shaped throughhole 131, through which the D-cutpart 121 of the conveyingroller 120 is inserted, is formed in the conveyingroller gear 130. Theintermediate gear 140 has a circularshaft insertion hole 141. Moreover, as shown inFIG. 17 , theintermediate gear 140 includes a small-diameterintermediate gear portion 142, which meshes with the conveyingroller gear 130, and a large-diameterintermediate gear portion 143 that meshes with thedrive transmission gear 150 and that has a diameter, which is larger than that of the small diameterintermediate gear portion 142. Furthermore, as shown inFIG. 19 , the intermediategear supporting shaft 160 includes an attachingportion 161 fixedly attached to theframe 110 by performing a caulking operation or the like. Additionally, as shown in FIGS. 17 to 19, the intermediategear supporting shaft 160 has a circular shape, which is substantially the same as that of theshaft insertion hole 141. - Next, a drive transmission operation of the conventional
thermal transfer printer 100 is described hereinbelow by referring toFIG. 17 . First, a driving force of the motor 113 (seeFIG. 16 ) is transmitted to thedrive transmission gear 150 through the drive shaft 113 a of themotor 113. Thus, thedrive transmission gear 150 rotates in the direction of an arrow M shown inFIG. 17 . Subsequently, the driving force of thedrive transmission gear 150 is transmitted to the large-diameterintermediate gear portion 143 of theintermediate gears 140. Thus, the large-diameterintermediate gear portion 143 and the small-diameterintermediate gear portion 142 rotate in the direction of an arrow N shown inFIG. 17 . Then, the driving force of the small-diameterintermediate gear portion 142 is transmitted to the conveyingroller gear 130. Thus, the conveyingroller gear 130 rotates in the direction of an arrow O shown inFIG. 17 . Consequently, the driving force is transmitted to the conveyingroller 120 through the D-cutpart 121 of theconveying roller 120, which is inserted into the D-shaped throughhole 131 of the conveyingroller gear 130. Thus, the conveyingroller 120 rotates. - In the conventional
thermal transfer printer 100 shown in FIGS. 16 to 19, at least one of theconveying roller gear 130, the small-diameterintermediate gear portion 142, the large-diameterintermediate gear portion 143, and thedrive transmission gear 150 may be eccentric due to manufacturing errors of the device, to abrasion caused after use of the device, and to thermal deformation thereof. In this case, it is difficult for the eccentric gear to be in contact with the adjacent gear so that an eccentric-gear-side part, whose diameter is equal to a reference pitch circle diameter of the eccentric gear, is brought into contact with an adjacent-gear-side part, whose diameter is equal to a reference pitch circle diameter of the adjacent gear. Thus, when the gears are driven, unevenness in the rotation of each of the gears occurs. Consequently, this conventional printer has a problem in that it is difficult to rotate the conveying roller gear 130 (or the conveying roller 120) at a constant rotational speed. - Further, the structure disclosed in JP-A-5-014787 is enabled to reduce unevenness in the rotational speed of a platen-roller-side gear in a case where an eccentric gear is used in a manufacturing stage (a stage in which the device is not used yet). Consequently, this conventional printer has a problem in that it is difficult to reduce the rotational speed of the platen-roller-side gear in a case where the gear becomes eccentric during the device is used.
- Thus, hitherto, to solve the problems, there has been proposed a structure enabled to rotate a conveying roller gear (or the conveying roller) at a constant rotational speed without causing unevenness in the rotation of the gear (see JP-A-10-123785).
- JP-A-10-123785 discloses an image forming apparatus provided with annular stopper members, which have a reference pitch circle diameter being equal to those of a swinging gear and a transfer roller gear and are coaxially connected to the swinging gear and the transfer roller gear, in a drive transmission structure in which a driving force from a photoconductive drum gear is transmitted to a transfer roller gear (or a conveying roller gear) through the swinging gear pushed in the direction of the transfer roller gear. The structure disclosed in JP-A-10-123785 prevents occurrences of unevenness in the rotational speed of the transfer roller by keeping the distance between the swinging gear and the transfer roller gear at a constant value through the use of the stopper members even when the distance between the centers of the photoconductive drum and the transfer roller changes.
- However, the structure disclosed in JP-A-10-123785 has a problem in that because a coupler, the spring and the idler gear are needed for enabling the swinging gear, which is used for transmitting the driving force from the photosensitive drum gear to the transfer roller gear (or the conveying roller gear), to swing, the number of components increases for that. Also, this conventional structure has a problem in that because annular stopper members each having a reference pitch circle diameter, which is equal to those of the swinging gear and the transfer roller gear, are separately provided therein, the number of components increases in this regard. Additionally, this conventional structure has a problem in that because no stopper members are provided between the idler gear and the swinging gear and between the idler gear and the photosensitive drum gear, unevenness in the rotation is caused therebetween.
- The invention is accomplished to solve the aforementioned problems. Accordingly, an object of the invention is to provide a drive transmission mechanism for a printer apparatus or the like, which is enabled to rotate a gear, which transmits a driving force, at a constant rotational speed without increasing the number of components.
- According to a first aspect of the invention, there is provided a drive transmission mechanism for a printer apparatus, which has a metallic conveying roller for conveying sheets, a resin conveying roller gear connected to one end portion of the conveying roller, a resin intermediate gear, provided with a shaft insertion hole, for rotating the conveying roller, a resin drive transmission gear, mounted on a drive shaft of a motor, for rotating the intermediate gear as the motor is driven, and an intermediate gear supporting shaft for rotatably supporting the shaft insertion hole of the intermediate gear. The intermediate gear includes a first-side intermediate gear portion meshed with the conveying roller gear, and also includes a second-side intermediate portion meshed with the drive transmission gear. The intermediate gear is disposed in a position, in which the intermediate gear is caused by a load of the conveying roller to bite into the conveying roller gear and the drive transmission gear, when the gears are driven. The resin conveying roller gear includes a conveying roller gear circular portion that is provided integrally with the conveying roller gear and that has a diameter being substantially equal to a reference pitch circle diameter of the conveying roller gear. The resin drive transmission gear includes a drive transmission gear circular portion that is provided integrally with the drive transmission gear and that has a diameter being substantially equal to a reference pitch circle diameter of the drive transmission gear. The resin intermediate gear further includes a first-side intermediate gear circular portion, which is provided integrally with the drive transmission gear and has a diameter being substantially equal to a reference pitch circle diameter of the first-side intermediate gear portion, and also includes a second-side intermediate gear circular portion that is provided integrally with the intermediate gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second-side intermediate gear portion. The intermediate gear supporting shaft is mounted in the shaft insertion hole of the intermediate gear in such a way as to provide a predetermined fitting clearance between the intermediate gear supporting shaft and the shaft insertion hole. The conveying roller gear circular portion is disposed in such a way as to be in contact with the first-side intermediate gear circular portion when the gears are driven. The drive transmission gear circular portion is disposed in such a manner as to be in contact with the second-side intermediate gear circular portion when the gears are driven.
- As described above, in the drive transmission mechanism for a printer apparatus according to the first aspect of the invention, the conveying roller gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the conveying roller gear is provided at the conveying roller gear. Moreover, the first-side intermediate gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the first-side intermediate gear portion of the intermediate gear is provided at the first-side intermediate gear portion of the intermediate gear for rotating the conveying roller gear. Thus, when the gears are driven, the conveying roller gear circular portion and the first-side intermediate gear circular portion are in contact with each other. Consequently, the conveying roller gear and the first-side intermediate gear portion of the intermediate gear can be meshed with each other so that a conveying-roller-gear-side part, whose diameter is equal to the reference pitch circle diameter the conveying roller gear, is in contact with a first-side-intermediate-gear-portion-side part, whose diameter is equal to the reference pitch circle diameter of the first-side intermediate gear portion. Thus, even when at least one of the conveying roller gear and the first-side intermediate gear portion of the intermediate gear is eccentric, each of the conveying roller gear and the intermediate gear can be rotated at a constant rotational speed without causing unevenness in the rotation thereof. Furthermore, the second-side intermediate gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the second-side intermediate gear portion of the intermediate gear is provided at the second-side intermediate gear portion of the intermediate gear. Moreover, the drive transmission gear circular portion having a diameter being substantially equal to the reference pitch circle diameter of the drive transmission gear is provided at the drive transmission gear for rotating the intermediate gear. Thus, when the gears are driven, the second-side intermediate gear portion of the intermediate gear and the drive transmission gear are in contact with each other. Consequently, the second-side intermediate gear portion of the intermediate gear and the drive transmission gear can be meshed with each other so that a second-side-intermediate-gear-portion-side part, whose diameter is equal to the reference pitch circle diameter of the second-side intermediate gear portion, is in contact with a drive-transmission-gear-side part, whose diameter is equal to the reference pitch circle diameter of the drive transmission gear. Thus, even when at least one of the second-side intermediate gear portion and the drive transmission gear is eccentric, each of the intermediate gear and the drive transmission gear can be rotated at a constant rotational speed without causing unevenness in the rotation thereof. Further, the conveying roller gear circular portion is provided integrally with the conveying roller gear, while the first-side intermediate gear circular portion is provided integrally with the first-side intermediate gear portion of the intermediate gear. Thus, even in a case where the conveying roller gear circular portion and the first-side intermediate gear circular portion are provided in the mechanism, the number of components does not increase. Consequently, each of the conveying roller gear and the intermediate gear can be rotated at a constant rotational speed without increasing the number of components. Additionally, the second-side intermediate gear circular portion is provided integrally with the second-side intermediate gear portion of the intermediate gear, while the drive transmission gear circular portion is provided integrally with the drive transmission gear. Thus, even in a case where the second-side intermediate gear circular portion and the drive transmission gear circular portion are provided in the mechanism, the number of components does not increase. Consequently, each of the intermediate gear and the drive transmission gear can be rotated at a constant rotational speed without increasing the number of components. Besides, the intermediate gear supporting shaft is mounted in the shaft insertion hole of the intermediate gear in such a way as to provide a predetermined fitting clearance between the intermediate gear supporting shaft and the shaft insertion hole. Thus, when the gears are driven, the intermediate gear can easily be moved in such a manner as to bite into the conveying roller gear and the drive transmission gear. Thus, the conveying roller gear circular portion can surely be in contact with the second-side intermediate gear circular portion, while the first-side intermediate gear circular potion can surely be in contact with the drive transmission gear circular portion. Consequently, without separately providing a mechanism for swinging (or moving) the intermediate gear in the transmission mechanism, the conveying roller gear can surely be meshed with the intermediate gear, while the intermediate gear can surely be meshed with the drive transmission gear so that a conveying-roller-gear-side part, whose diameter is equal to the reference pitch circle diameter of the conveying roller gear, is in contact with an intermediate-gear-side part, whose diameter is equal to the reference pitch circle diameter of the intermediate gear, and that the intermediate-gear-side part, whose diameter is equal to the reference pitch circle diameter of the intermediate gear, is in contact with a drive-transmission-gear-side part, whose diameter is equal to the reference pitch circle diameter of the drive transmission gear. Furthermore, correction for unevenness in the rotation is performed on the engagement between the drive transmission gear and the intermediate gear, in addition to the engagement between the intermediate gear and the conveying roller gear. Thus, the unevenness in the rotation, which is caused at the drive transmission gear, is corrected at two places. Thus, as compared with a case in which such unevenness in the rotation is corrected at one place, the conveying roller gear can more surely be rotated at a constant rotational speed.
- According to a second aspect of the invention, there is provided a drive transmission mechanism that includes a first gear and a second gear having a second first-side gear portion for rotating the first gear. The first gear includes a first circular portion that is provided integrally with the first gear and that has a diameter being substantially equal to a reference pitch circle diameter of the first gear. The second gear includes a second first-side circular portion that is provided integrally with the second first-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second first-side gear portion. The first circular portion is disposed in such a way as to be in contact with the second first-side circular portion when the gears are driven.
- As described above, in the drive transmission mechanism according to the second aspect of the invention, the first circular portion having a diameter being substantially equal to the reference pitch circle diameter of the first gear is provided on the first gear. Also, the second first-side circular portion having a diameter being substantially equal to the reference pitch circle diameter of the second first-side gear portion is provided at the second first-side gear portion for rotating the first gear. Thus, when the gears are driven, the first circular portion and the second first-side circular portion are in contact with each other. Consequently, the first gear and the second first-side gear portion of the second gear can be meshed with each other so that a first-gear-side part, whose diameter is equal to the reference pitch circle diameter of the first gear, is in contact with a second-first-side-gear-portion-side part, whose diameter is equal to the reference pitch circle diameter of the second first-side gear portion. Thus, even when at least one of the first gear and the second gear is eccentric, each of the first gear and the second gear can be rotated at a constant rotational speed without causing unevenness in the rotation thereof. Further, even in a case where the first circular potion is provided integrally with the first gear and where second first-side circular portion is provided integrally with the second first-side gear portion of the second gear to thereby provide the first circular portion and the second first-side circular portion in the mechanism, the number of components does not increase. Consequently, each of the first gear and the second gear can be rotated at a constant rotational speed without increasing the number of components.
- Preferably, the drive transmission mechanism according to the second aspect of the invention is adapted so that the second gear has a shaft insertion hole, and further includes a second gear supporting shaft mounted in such a manner as to rotatably support the shaft insertion hole and as to provide a predetermined fitting clearance between the second gear supporting shaft and the shaft insertion hole. With such a configuration, when the gears are driven, the second gear can easily be moved in such a way as to bite into the first gear. Thus, the first circular portion and the second first-side circular portion can surely be in contact with each other. Consequently, the first gear and the second gear can mesh with each other, without separately being provided with a mechanism for swinging (or moving), so that a first-gear-side part, whose diameter is equal to a reference pitch circle diameter of the first gear, is in contact with a second-gear-side part, whose diameter is equal to a reference pitch circle diameter of the second gear.
- Preferably, the drive transmission mechanism according to the second aspect of the invention further includes a third gear for rotating the second gear. The second gear further includes a second second-side gear portion meshed with the third gear, and also includes a second second-side circular portion that is provided integrally with the second second-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second second-side gear portion. The third gear includes a third circular portion that is provided integrally with the third gear and that has a diameter being substantially equal to a reference pitch circle diameter of the third gear. The second second-side circular portion is disposed in such a manner as to be in contact with the third circular portion when the gears are driven. With such a configuration, when the gears are driven, the third circular portion and the second second-side circular portion are in contacted with each other. Thus, the third gear and the second second-side gear portion of the second gear can be meshed with each other so that a third-gear-side part, whose diameter is equal to a reference pitch circle diameter of the third gear, is in contact with a second-second-side-gear-portion-side part, whose diameter is equal to a reference pitch circle diameter of the second second-side gear portion. Consequently, even when at least one of the third gear and the second gear is eccentric, each of the third gear and the second gear can be rotated at a constant rotational speed without causing unevenness in the rotation thereof. Further, even in a case where the third circular portion is provided integrally with the third gear and where the second second-side circular portion are provided integrally with the second second-side gear portion of the second gear to thereby provide the third circular portion and the second second-circular portion in the mechanism, the number of components does not increase. Consequently, the third gear and the second second-side gear portion can be rotated at a constant rotational speed without increasing the number of components. Moreover, unevenness in the rotation, which occurs at the upstream side of driving-force transmission from the third gear, can be corrected at two places by providing the third circular portion at the third gear for rotating the second gear and also providing the second second-side circular portion at the second second-side gear portion included in the second gear. Thus, as compared with a case where such unevenness in the rotation is corrected at one place, the first gear can more surely be rotated at a constant rotational speed.
- A printer apparatus according to the invention may include at least one of the drive transmission mechanisms according to the second aspect of the invention. With such a configuration, the gear included in the apparatus can be rotated at a constant rotational speed without increasing the number of components and without causing unevenness in the rotation thereof. Consequently, the apparatus of the invention can obtain an advantage of reducing unevenness in printing images on sheets, without increasing the number of components.
- These and other objects and advantages of this invention will become more fully apparent from the following detailed description taken with the accompanying drawings in which:
-
FIG. 1 is a perspective view illustrating a thermal transfer printer according to a first embodiment of the invention; -
FIG. 2 is a side view illustrating a drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown inFIG. 1 ; -
FIG. 3 is a top view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown inFIG. 1 ; -
FIG. 4 is a cross-sectional view taken along line 200-200 inFIG. 2 ; -
FIG. 5 is a side view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown inFIG. 2 , at the time of driving the printer; -
FIG. 6 is a top view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown inFIG. 3 , at the time of driving the printer; -
FIG. 7 is a cross-sectional view taken along line 300-300 inFIG. 5 ; -
FIG. 8 is a cross-sectional view taken along line 400-400 inFIG. 5 ; -
FIG. 9 is a side view illustrating a drive transmission mechanism of a thermal transfer printer according to a second embodiment of the invention; -
FIG. 10 is a top view illustrating the drive transmission mechanism of a thermal transfer printer according to the second embodiment of the invention; -
FIG. 11 is a cross-sectional view taken along line 500-500 inFIG. 9 ; -
FIG. 12 is a side view illustrating the drive transmission mechanism of the thermal transfer printer according to the second embodiment of the invention, which is shown inFIG. 9 , at the time of driving the printer; -
FIG. 13 is a top view illustrating the drive transmission mechanism of the thermal transfer printer according to the first embodiment of the invention, which is shown inFIG. 10 , at the time of driving the printer; -
FIG. 14 is a cross-sectional view taken along line 600-600 inFIG. 9 ; -
FIG. 15 is a cross-sectional view taken along line 700-700 inFIG. 9 ; -
FIG. 16 is a perspective view illustrating a conventional thermal transfer printer; -
FIG. 17 is a side view illustrating a drive transmission mechanism of the conventional thermal transfer printer shown inFIG. 16 ; -
FIG. 18 is a top view illustrating the drive transmission mechanism of the conventional thermal transfer printer shown inFIG. 16 ; and -
FIG. 19 is a cross-sectional view taken along line 800-800 inFIG. 17 . - Hereinafter, embodiments of the invention are described with reference to the accompanying drawings.
-
FIG. 1 is a perspective view illustrating a thermal transfer printer according to a first embodiment. FIGS. 2 to 4 are views illustrating the thermal transfer printer according to the first embodiment of the invention. First, the structure of a thermal transfer printer 1 according to the first embodiment of the invention is described hereinbelow by referring to FIGS. 1 to 4. - As shown in
FIG. 1 , the thermal transfer printer 1 according to the first embodiment of the invention has ametallic frame 10, a thermal transferfilm accommodating member 11, asheet feeding roller 12, amotor bracket 14 to which amotor 13 is attached, a film take-upmember 15, a sheet feedingroller gear 16, pluralintermediate gears 17, a metallic conveyingroller 20, a resin conveyingroller gear 30 connected to an end portion of the conveyingroller 20, and a resinintermediate gear 40 for rotating the conveyingroller gear 30. Further, as shown in FIGS. 2 to 4, the thermal transfer printer 1 according to the first embodiment of the invention has a resindrive transmission gear 50, which is connected to adrive shaft 13 a of themotor 13, for rotating theintermediate gear 40, and an intermediategear support shaft 60 rotatably supporting theintermediate gear 40. Incidentally, the thermal transfer printer 1 is an example of the “printer apparatus” of the invention. The conveyingroller gear 30 is an example of the “first gear” of the invention. Theintermediate gear 40 is an example of the “second gear”. Further, thedrive transmission gear 50 is an example of the “third gear” of the invention. The intermediategear supporting shaft 60 is an example of the “second gear supporting shaft” of the invention. - As shown in
FIG. 1 , theframe 10 is U-shaped. The thermal transferfilm accommodating member 11 and thesheet feeding roller 12 are disposed on the inner surface side of theframe 10. Moreover, themotor 13 transmits a driving force to thedrive transmission gear 50 through thedrive shaft 13 a of themotor 13. Furthermore, themotor bracket 14 is mounted on the outer surface of theframe 10. Additionally, the film take-upmember 15, the sheet feedingroller gear 16, and the pluralintermediate gears 17 are placed between theframe 10 and themotor bracket 14. These pluralintermediate gears 17 are placed so that the film take-upmember 15 and the sheet feedingroller gear 16 can be driven by thesingle motor 13. Further, as shown inFIGS. 1 and 4 , the conveyingroller 20 is disposed under the thermal transferfilm accommodating member 11 on the inner surface side of theframe 10, and rotatably mounted on theframe 10 by abearing 18. As shown inFIGS. 2 and 4 , a D-cutpart 21 is formed in an end portion of this conveyingroller 20 by performing a cutting work operation or the like. Furthermore, a D-shaped throughhole 31, through which the D-cutpart 21 of the conveyingroller 20 is inserted, is formed in the conveyingroller gear 30. - The
intermediate gear 40 has a circularshaft insertion hole 41. Moreover, as shown inFIG. 2 , theintermediate gear 40 includes a small-diameterintermediate gear portion 42, which meshes with the conveyingroller gear 30, and a large-diameterintermediate gear portion 43 that meshes with thedrive transmission gear 50 and that has a diameter, which is larger than that of the small diameterintermediate gear portion 42. Incidentally, the small-diameterintermediate gear portion 42 is an example of each of the “first-side intermediate gear portion” and the “second first-side gear portion”. The large-diameterintermediate gear portion 43 is an example of each of the “second-side intermediate gear portion” and the “second second-side gear portion”. Furthermore, as shown inFIG. 4 , the intermediategear supporting shaft 60 includes an attachingportion 61 fixedly attached to theframe 10 by performing a caulking operation or the like. - Incidentally, in the first embodiment, as shown in FIGS. 2 to 4, the intermediate
gear supporting shaft 60 is configured in such a manner as to rotatably support ashaft insertion hole 41 of theintermediate gear 40 and as to provide a predetermined fitting clearance (about 0.2 mm in the first embodiment) between theshaft 60 and theshaft insertion hole 41. Further, a conveying roller gearcircular portion 32 having a diameter, which is substantially equal to the reference pitch circle diameter of the conveyingroller gear 30, is formed integrally with the resin conveyingroller gear 30. Incidentally, the conveying roller gearcircular portion 32 is an example of the “first circular portion”. Furthermore, in the resinintermediate gear 40, a small-diameter intermediate gearcircular portion 44 having a diameter, which is substantially equal to the reference pitch circle diameter of the small-diameterintermediate gear portion 42, is provided integrally with the small-diameterintermediate gear portion 42. Incidentally, the small-diameter intermediate gearcircular portion 44 is an example of each of the “first-side intermediate gear circular portion” and the “second first-side circular portion”. - Further, in the case of the first embodiment, in the resin
intermediate gear 40, a large-diameter intermediate gearcircular portion 45 having a diameter, which is substantially equal to the reference pitch circle diameter of the large-diameterintermediate gear portion 43, is provided integrally with the large-diameterintermediate gear portion 43. Incidentally, the large-diameter intermediate gearcircular portion 45 is an example of each of the “second-side intermediate gear circular portion” and the “second second-side circular portion”. Furthermore, a drive transmission gearcircular portion 51 having a diameter, which is substantially equal to the reference pitch circle diameter of thedrive transmission gear 50, is provided integrally with thedrive transmission gear 50. Incidentally, the drive transmission gearcircular portion 51 is an example of the “third circular portion”. Additionally, the conveying roller gearcircular portion 32 is disposed so that when the gears are driven, the conveying roller gearcircular portion 32 is in contact with the small-diameter intermediatecircular portion 44. Further, the drive transmission gearcircular portion 51 is disposed so that when the gears are driven, the drive transmission gearcircular portion 51 is in contact with the large-diameter intermediate gearcircular portion 45. - FIGS. 5 to 8 are views illustrating the drive transmission mechanism at the time of driving the thermal transfer printer according to the first embodiment of the invention, which is shown in
FIG. 1 . Next, a drive transmission operation of the thermal transfer printer 1 according to the first embodiment of the invention is described hereinbelow by referring to FIGS. 2 to 8. - First, as shown in FIGS. 2 to 4, before the gears are driven, the conveying roller gear
circular portion 32 and the small-diameter intermediate gearcircular portion 44 are not in contact with each other. Also, the drive transmission gearcircular portion 51 and the large-diameter intermediate gearcircular portion 45 are not in contact with each other. When themotor 13 is energized in this state, a driving force of themotor 13 is transmitted to thedrive transmission gear 50 through thedrive shaft 13 a of themotor 13. Thus, thedrive transmission gear 50 rotates in the direction of an arrow A shown inFIG. 5 . Subsequently, the driving force of thedrive transmission gear 50 is transmitted to the large-diameterintermediate gear portion 43 of theintermediate gear 40. Thus, the large-diameter gear portion 43 and the small-diameterintermediate gear portion 44 rotate in the direction of an arrow B shown inFIG. 5 . At that time, a force pushing the large-diameterintermediate gear portion 43 in the direction of an arrow D shown inFIG. 5 , which is caused due to the driving force transmitted from thedrive transmission gear 50, is exerted on the large-diameterintermediate gear portion 43 of theintermediate gear 40. - Subsequently, the driving force of the small-diameter
intermediate gear portion 42 is transmitted to the conveyingroller gear 30. Thus, the conveyingroller gear 30 rotates in the direction of an arrow C ofFIG. 5 . Consequently, the driving force is transmitted to the conveyingroller 20 through the D-cutpart 21 of the conveyingroller 20, which is inserted into the D-shaped throughhole 31 of the conveyingroller gear 30. Thus, the conveyingroller 20 rotates. At that time, a force pushing the small-diameterintermediate gear portion 42 in the direction of an arrow E shown inFIG. 5 and originating from a force of the conveyingroller gear 30 that is always forced by a load, which is caused by the conveyingroller 20 and soon, to stop, is exerted on the small-diameterintermediate gear portion 42 of theintermediate gear 40. Thus, when the gears are driven, a force, which is synthesized from a force acting in the direction of the arrow D shown inFIG. 5 and a force acting in the direction of the arrow E shown inFIG. 5 and pushes theintermediate gear 40 in the direction of an arrow F shown inFIG. 5 , is exerted on theintermediate gear 40. Consequently, theintermediate gear 40 moves (or swings) in the direction of the arrow F shown inFIG. 5 by the fitting clearance (about 0.2 mm) from the intermediategear supporting shaft 60 to theshaft insertion hole 41 of theintermediate gear 40 and bites into the conveyingroller gear 30 and thedrive transmission gear 50. Thus, when the gears are driven, the conveying roller gearcircular portion 32 and the small-diameter gearcircular portion 44 are brought into contact with each other and rotate, while the drive transmission gearcircular portion 51 and the large-diameter gearcircular portion 45 are put into contact with each other and rotate. - As described above, in the first embodiment, the conveying roller gear
circular portion 32 having a diameter, which is substantially equal to the reference pitch circle diameter of the conveyingroller gear 30, is provided on the conveyingroller gear 30. Also, the small-diameter intermediate gearcircular portion 44 having a diameter, which is substantially equal to the reference pitch circle diameter of the small-diameterintermediate gear portion 42 of theintermediate gear 40, is provided on the small-diameterintermediate gear portion 42 of theintermediate gear 40, which rotates the conveyingroller gear 30. Thus, when the gears are driven, the conveying roller gearcircular portion 32 and the small-diameter intermediate gearcircular portion 44 are in contact with each other. Consequently, the conveyingroller gear 30 and the small-diameterintermediate gear portion 42 of theintermediate gear 40 can be meshed with each other so that a part at the side of conveyingroller gear 30, which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of the small-diameterintermediate gear portion 42, which has a diameter being equal to the reference pitch circle diameter thereof. Thus, even when at least one of the conveyingroller gear 30 and the small-diameterintermediate gear portion 42 of theintermediate gear 40 is eccentric, each of the conveyingroller gear 30 and theintermediate gear 40 can be rotated at a constant rotational speed without causing unevenness in the rotation thereof. - Further, in the first embodiment, the large-diameter intermediate gear
circular portion 45 having a diameter, which is substantially equal to the reference pitch circle diameter of the large-diameterintermediate gear portion 43 of theintermediate gear 40, is provided on the large-diameterintermediate gear portion 43 of theintermediate gear 40. Also, the drive transmission gearcircular portion 51 having a diameter, which is substantially equal to the reference pitch circle diameter of thedrive transmission gear 50, is provided on thedrive transmission gear 50 that rotates theintermediate gear 40. Thus, when the gears are driven, the large-diameterintermediate gear portion 43 of theintermediate gear 40 and thedrive transmission gear 50 are in contact with each other. Consequently, the large-diameterintermediate gear portion 43 of theintermediate gear 40 and thedrive transmission gear 50 can be meshed with each other so that a part at the side of the large-diameterintermediate gear portion 43, which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of thedrive transmission gear 50, which has a diameter being equal to the reference pitch circle diameter thereof. Thus, even when at least one of the large-diameterintermediate gear portion 43 of theintermediate gear 40 and thedrive transmission gear 50 is eccentric, each of theintermediate gear 40 and thedrive transmission gear 50 can be rotated at a constant rotational speed without causing unevenness in the rotation thereof. - Furthermore, in the first embodiment, the conveying roller gear
circular portion 32 is provided integrally with the conveyingroller gear 30, while the small-diameter intermediate gearcircular portion 44 is provided integrally with the small-diameterintermediate gear portion 42 of theintermediate gear 40. Thus, even when the conveying roller gearcircular portion 32 and the small-diameter intermediate gearcircular portion 44 are provided therein, the number of components does not increase. Consequently, the conveyingroller gear 30 and theintermediate gear 40 can be rotated at a constant rotational speed without increasing the number of components. - Additionally, in the first embodiment, the large-diameter intermediate gear
circular portion 45 is provided integrally with the large-diameterintermediate gear portion 42 of theintermediate gear 40, while the drive transmission gearcircular portion 51 is provided integrally with thedrive transmission gear 50. Thus, even when the large-diameter intermediate gearcircular portion 45 and the drive transmission gearcircular portion 51 are provided therein, the number of components does not increase. Consequently, theintermediate gear 40 and thedrive transmission gear 50 can be rotated at a constant rotational speed without increasing the number of components. - Further, in the first embodiment, the intermediate
gear supporting shaft 60 is mounted in such a way as to provide the predetermined fitting clearance (about 0.2 mm) between the intermediategear supporting shaft 60 and theshaft insertion hole 41 of theintermediate gear 40. Thus, when the gears are driven, theintermediate gear 40 can easily be moved in such a manner as to bite into the conveyingroller gear 30 and thedrive transmission gear 50. Consequently, the conveying roller gearcircular portion 32 can reliably be in contact with the large-diameter intermediate gearcircular portion 45, while the small-diameter intermediate gearcircular portion 44 can reliably be in contact with the drive transmission gearcircular portion 51. Thus, the conveyingroller gear 30 can reliably be meshed with theintermediate gear 40, without separately providing a mechanism for swinging (or moving) theintermediate gear 40, so that a part at the side of the conveyingroller gear 30, which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of theintermediate gear 40, which has a diameter being equal to the reference pitch circle diameter thereof. Also, thedrive transmission gear 50 can reliably be meshed with theintermediate gear 40, without separately providing a mechanism for swinging (or moving) theintermediate gear 40, so that a part at the side of thedrive transmission 50, which has a diameter being equal to the reference pitch circle diameter thereof, is in contact with a part at the side of theintermediate gear 40, which has a diameter being equal to the reference pitch circle diameter thereof. - Further, correction for unevenness in the rotation is performed on the engagement between the
drive transmission gear 50 and theintermediate gear 40, in addition to the engagement between theintermediate gear 40 and the conveyingroller gear 30. Thus, the unevenness in the rotation, which is caused at thedrive transmission gear 50, is corrected at two places. Thus, as compared with a case in which such unevenness in the rotation is corrected at one place, this embodiment can more surely rotate the conveyingroller gear 30 at a constant rotational speed. - FIGS. 9 to 11 are views illustrating a drive transmission mechanism of the thermal transfer printer according to a second embodiment of the invention. Referring to FIGS. 9 to 11, it is illustrated that this second embodiment has a configuration in which a convex
annular portion 41 a is provided in ashaft insertion hole 41 of anintermediate gear 40 a and which constituents respectively corresponding to the large-diameter intermediate gearcircular portion 45 of theintermediate gear 40 and the drive transmission gearcircular portion 51 of thedrive transmission gear 50 of the thermal transfer printer according to the first embodiment of the invention illustrated in FIGS. 2 to 8 are omitted. Incidentally, the remaining constituents of the second embodiment other than theintermediate gear 40 a and thedrive transmission gear 50 a are similar to those of the first embodiment. - Concretely, in the second embodiment, the convex
annular portion 41 a of theintermediate gear 40 a is formed on a part, which is provided at the side of theframe 10, in theshaft insertion hole 41, as shown inFIG. 11 . Further, theannular portion 41 a of theintermediate gear 40 a is formed in such a way as to provide almost no fitting clearance between theannular portion 41 a and the outer periphery of the intermediategear supporting shaft 60. - FIGS. 12 to 15 are views illustrating the drive transmission mechanism at the time of driving a thermal transfer printer according to the second embodiment of the invention. Next, a drive transmission operation of the thermal transfer printer 70 according to the first embodiment of the invention is described hereinbelow by referring to FIGS. 9 to 15. First, as shown in FIGS. 9 to 11, before the gears are driven, a conveying roller gear
circular portion 32 and a small-diameter intermediate gearcircular portion 44 are not in contact with each other. When themotor 13 is energized in this state, a driving force of amotor 13 is transmitted to adrive transmission gear 50 a through adrive shaft 13 a of themotor 13. Thus, thedrive transmission gear 50 a rotates in the direction of an arrow G shown inFIG. 12 . Subsequently, the driving force of thedrive transmission gear 50 a is transmitted to a large-diameterintermediate gear portion 43 of theintermediate gear 40 a. Thus, the large-diameter gear portion 43 and the small-diameterintermediate gear portion 44 rotate in the direction of an arrow H shown inFIG. 12 . At that time, a force pushing the large-diameterintermediate gear portion 43 in the direction of an arrow J shown inFIG. 12 , which is caused due to the driving force transmitted from thedrive transmission gear 50 a, is exerted on the large-diameterintermediate gear portion 43 of theintermediate gear 40 a. - Subsequently, the driving force of the small-diameter
intermediate gear portion 42 is transmitted to the conveyingroller gear 30. Thus, the conveyingroller gear 30 rotates in the direction of an arrow I ofFIG. 12 . Consequently, the driving force is transmitted to the conveyingroller 20 through a D-cutpart 21 of the conveyingroller 20, which is inserted into a D-shaped throughhole 31 of the conveyingroller gear 30. Thus, the conveyingroller 20 rotates. At that time, a force pushing the small-diameterintermediate gear portion 42 in the direction of an arrow K shown inFIG. 12 and originating from a force of the conveyingroller gear 30 that is always forced by a load, which is caused by the conveyingroller 20 and soon, to stop, is exerted on the small-diameterintermediate gear portion 42 of theintermediate gear 40 a. Thus, when the gears are driven, a force, which is synthesized from a force acting in the direction of the arrow J shown inFIG. 12 and a force acting in the direction of the arrow K shown inFIG. 12 and pushes theintermediate gear 40 a in the direction of an arrow L shown inFIG. 12 , is exerted on theintermediate gear 40 a. Consequently, theintermediate gear 40 a moves (or swings) in the direction of the arrow L shown inFIG. 12 by the fitting clearance (about 0.2 mm) from the intermediategear supporting shaft 60 to theshaft insertion hole 41 of theintermediate gear 40 a. Incidentally, theintermediate gear 40 a is rotatably supported by the intermediategear supporting shaft 60 on theannular portion 41 a formed in theshaft insertion hole 41 of theintermediate gear 40 a in a state in which there is nearly no fitting clearance. Consequently, theintermediate gear 40 a is inclined and bites into the conveyingroller gear 30, as shown inFIG. 15 . Thus, when the gears are driven, the conveying roller gearcircular portion 32 and the small-diameter gearcircular portion 44 are brought into contact with each other and rotate. - Incidentally, advantages of the second embodiment are similar to those of the first embodiment.
- Incidentally, it should be understood that the embodiments disclosed herein are illustrative in all respects, and that the invention is not limited thereto. The scope of the invention is defined by the scope of the appended claims rather than by the description of the embodiments. Furthermore, all changes, which fall within the scope of the claims, or equivalence of the scope of the claims, are included by the scope of the invention.
- For example, although examples of applying the invention to the thermal transfer printer serving as an example of an apparatus having a drive transmission mechanism have been disclosed in the descriptions of the first and second embodiments, the invention is not limited thereto. The invention is not limited thereto. The invention may be widely applied to apparatuses each having a drive transmission mechanism other than the thermal transfer printer.
- Further, although the shaft insertion hole of the intermediate gear and the intermediate gear supporting shaft are circularly cross-sectionally formed in each of the first and second embodiments, the invention is not limited thereto. The shaft insertion hole of the intermediate gear and the intermediate gear supporting shaft may be formed into another shape including an elliptical shape.
- Furthermore, although the description of the first and second embodiments have described examples in which the circular portions are provided on one or two sets of the gears meshed with one another when the driving force is transmitted, the invention is not limited thereto. The circular portions may be formed on the gears of three sets or more, which are meshed with one another when the driving force is transmitted. Alternatively, the circular portions may be provided on all the gears of the drive transmission mechanism.
Claims (5)
1. A drive transmission mechanism for a printer apparatus comprising:
a metallic conveying roller for conveying sheets;
a resin conveying roller gear connected to one end portion of the conveying roller;
a resin intermediate gear, provided with a shaft insertion hole, for rotating the conveying roller;
a resin drive transmission gear, mounted on a drive shaft of a motor, for rotating the intermediate gear as the motor is driven; and
an intermediate gear supporting shaft for rotatably supporting the shaft insertion hole of the intermediate gear, wherein:
the intermediate gear includes a first-side intermediate gear portion meshed with the conveying roller gear, and also includes a second-side intermediate portion meshed with the drive transmission gear;
the intermediate gear is disposed in a position, in which the intermediate gear is caused by a load of the conveying roller to bite into the conveying roller gear and the drive transmission gear, when the gears are driven;
the resin conveying roller gear includes a conveying roller gear circular portion that is provided integrally with the conveying roller gear and that has a diameter being substantially equal to a reference pitch circle diameter of the conveying roller gear;
the resin drive transmission gear includes a drive transmission gear circular portion that is provided integrally with the drive transmission gear and that has a diameter being substantially equal to a reference pitch circle diameter of the drive transmission gear;
the resin intermediate gear further includes a first-side intermediate gear circular portion, which is provided integrally with the drive transmission gear and has a diameter being substantially equal to a reference pitch circle diameter of the first-side intermediate gear portion, and also includes a second-side intermediate gear circular portion that is provided integrally with the intermediate gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second-side intermediate gear portion;
the intermediate gear supporting shaft is mounted in the shaft insertion hole of the intermediate gear in such a way as to provide a predetermined fitting clearance between the intermediate gear supporting shaft and the shaft insertion hole;
the conveying roller gear circular portion is disposed in such a way as to be in contact with the first-side intermediate gear circular portion when the gears are driven; and
the drive transmission gear circular portion is disposed in such a manner as to be in contact with the second-side intermediate gear circular portion when the gears are driven.
2. A drive transmission mechanism comprising:
a first gear; and
a second gear having a second first-side gear portion for rotating the first gear, wherein:
the first gear includes a first circular portion that is provided integrally with the first gear and that has a diameter being substantially equal to a reference pitch circle diameter of the first gear;
the second gear includes a second first-side circular portion that is provided with the second first-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second first-side gear portion; and
the first circular portion is disposed in such a way as to be in contact with the second first-side circular portion when the gears are driven.
3. The drive transmission mechanism according to claim 2 , further comprising:
a shaft insertion hole included the second gear; and
a second gear supporting shaft mounted in such a manner as to rotatably support the shaft insertion hole and as to provide a predetermined fitting clearance between the second gear supporting shaft and the shaft insertion hole.
4. The drive transmission mechanism according to claim 2 , further comprising:
a third gear for rotating the second gear, wherein
the second gear further includes a second second-side gear portion meshed with the third gear, and also includes a second second-side circular portion that is provided integrally with the second second-side gear portion and that has a diameter being substantially equal to a reference pitch circle diameter of the second second-side gear portion;
the third gear includes a third circular portion that is provided integrally with the third gear and that has a diameter being substantially equal to a reference pitch circle diameter of the third gear; and
the second second-side circular portion is disposed in such a manner as to be in contact with the third circular portion when the gears are driven.
5. The drive transmission mechanism according to claim 2 , wherein
the second first-side circular portion is provided integrally with the second first-side gear portion
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-001618 | 2004-01-07 | ||
JP2004001618A JP2005194033A (en) | 2004-01-07 | 2004-01-07 | Drive transmission mechanism and drive transmission mechanism of printer device |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050146090A1 true US20050146090A1 (en) | 2005-07-07 |
Family
ID=34709010
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/029,467 Abandoned US20050146090A1 (en) | 2004-01-07 | 2005-01-06 | Drive transmission mechanism and drive transmission mechanism for printer apparatus |
Country Status (2)
Country | Link |
---|---|
US (1) | US20050146090A1 (en) |
JP (1) | JP2005194033A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090057985A1 (en) * | 2007-08-29 | 2009-03-05 | Avision Inc. | Paper pick-up mechanism and feeder using the same |
US20110068533A1 (en) * | 2009-09-18 | 2011-03-24 | Thomas Sheng | Sheet transporting apparatus having gear assembly for mounting rotating shaft, and scanner and image processing apparatus using the same |
US20180088518A1 (en) * | 2016-09-29 | 2018-03-29 | Canon Kabushiki Kaisha | Driving device and image forming apparatus |
CN108328390A (en) * | 2018-03-23 | 2018-07-27 | 深圳市领创精密机械有限公司 | A kind of coiled strip film synchronous conveying system |
Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3443449A (en) * | 1967-10-16 | 1969-05-13 | Ritter Pfaudler Corp | Gear engagement device |
US3589205A (en) * | 1968-07-11 | 1971-06-29 | Sybron Corp | Rack and pinion synchronizing mechanism |
US4463683A (en) * | 1981-07-21 | 1984-08-07 | Georg Uttscheid | Rack and pinion drive trolley with slip-ring drive wheel |
US4691911A (en) * | 1985-07-31 | 1987-09-08 | Seiko Epson Kabushiki Kaisha | Paper feeding apparatus for printers |
US4767114A (en) * | 1985-07-30 | 1988-08-30 | Kabushiki Kaisha Toshiba | Sheet feeder |
US4893806A (en) * | 1988-07-25 | 1990-01-16 | Technical Support Services, Inc. | Pinch roller device |
US5213001A (en) * | 1990-05-21 | 1993-05-25 | Ucc Corporation | Power transmission element having increased torque capacity |
US5302046A (en) * | 1991-12-18 | 1994-04-12 | Man Roland Druckmashinen Ag | Clamping mechanism for frictionally engaging and securing together gear drive components |
US5528946A (en) * | 1994-05-06 | 1996-06-25 | Yadegar; Iraj | Apparatus for conversion of reciprocating motion to rotary motion and vise versa |
US5553842A (en) * | 1994-10-17 | 1996-09-10 | Hewlett-Packard Company | Precision referencing/latching system for document separation and transport in a scanning unit |
US5632684A (en) * | 1995-10-24 | 1997-05-27 | Xerox Corporation | Stepped shaft assembly |
US5791646A (en) * | 1996-08-19 | 1998-08-11 | Behavior Tech Computer Corp. | Automatic document feeder |
US5971390A (en) * | 1998-02-11 | 1999-10-26 | Lexmark International, Inc. | Sheet aligning apparatus |
US6076419A (en) * | 1999-01-25 | 2000-06-20 | Lexmark International, Inc. | Gear arrangement |
US20020135122A1 (en) * | 2001-03-23 | 2002-09-26 | Canon Kabushiki Kaisha | Image recording apparatus |
US20020142881A1 (en) * | 2001-03-29 | 2002-10-03 | Bodtker Joen Christen | Low noise planetary isolator |
US20040007807A1 (en) * | 2000-07-19 | 2004-01-15 | Hitoshi Fujiwara | Paper sheet treating device and recorder |
US20040195756A1 (en) * | 2003-04-01 | 2004-10-07 | Yu-Jen Su | Paper pickup mechanism |
US20050189699A1 (en) * | 2004-02-04 | 2005-09-01 | Canon Kabushiki Kaisha | Sheet feeding apparatus, and image forming apparatus and image reading apparatus respectively equipped with sheet feeding apparatus |
US20050225625A1 (en) * | 2004-04-13 | 2005-10-13 | Funai Electric Co., Ltd. | Image forming apparatus and thermal transfer printer |
-
2004
- 2004-01-07 JP JP2004001618A patent/JP2005194033A/en active Pending
-
2005
- 2005-01-06 US US11/029,467 patent/US20050146090A1/en not_active Abandoned
Patent Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3443449A (en) * | 1967-10-16 | 1969-05-13 | Ritter Pfaudler Corp | Gear engagement device |
US3589205A (en) * | 1968-07-11 | 1971-06-29 | Sybron Corp | Rack and pinion synchronizing mechanism |
US4463683A (en) * | 1981-07-21 | 1984-08-07 | Georg Uttscheid | Rack and pinion drive trolley with slip-ring drive wheel |
US4767114A (en) * | 1985-07-30 | 1988-08-30 | Kabushiki Kaisha Toshiba | Sheet feeder |
US4691911A (en) * | 1985-07-31 | 1987-09-08 | Seiko Epson Kabushiki Kaisha | Paper feeding apparatus for printers |
US4893806A (en) * | 1988-07-25 | 1990-01-16 | Technical Support Services, Inc. | Pinch roller device |
US5213001A (en) * | 1990-05-21 | 1993-05-25 | Ucc Corporation | Power transmission element having increased torque capacity |
US5302046A (en) * | 1991-12-18 | 1994-04-12 | Man Roland Druckmashinen Ag | Clamping mechanism for frictionally engaging and securing together gear drive components |
US5528946A (en) * | 1994-05-06 | 1996-06-25 | Yadegar; Iraj | Apparatus for conversion of reciprocating motion to rotary motion and vise versa |
US5553842A (en) * | 1994-10-17 | 1996-09-10 | Hewlett-Packard Company | Precision referencing/latching system for document separation and transport in a scanning unit |
US5632684A (en) * | 1995-10-24 | 1997-05-27 | Xerox Corporation | Stepped shaft assembly |
US5791646A (en) * | 1996-08-19 | 1998-08-11 | Behavior Tech Computer Corp. | Automatic document feeder |
US5971390A (en) * | 1998-02-11 | 1999-10-26 | Lexmark International, Inc. | Sheet aligning apparatus |
US6076419A (en) * | 1999-01-25 | 2000-06-20 | Lexmark International, Inc. | Gear arrangement |
US20040007807A1 (en) * | 2000-07-19 | 2004-01-15 | Hitoshi Fujiwara | Paper sheet treating device and recorder |
US20020135122A1 (en) * | 2001-03-23 | 2002-09-26 | Canon Kabushiki Kaisha | Image recording apparatus |
US20020142881A1 (en) * | 2001-03-29 | 2002-10-03 | Bodtker Joen Christen | Low noise planetary isolator |
US20040195756A1 (en) * | 2003-04-01 | 2004-10-07 | Yu-Jen Su | Paper pickup mechanism |
US20050189699A1 (en) * | 2004-02-04 | 2005-09-01 | Canon Kabushiki Kaisha | Sheet feeding apparatus, and image forming apparatus and image reading apparatus respectively equipped with sheet feeding apparatus |
US20050225625A1 (en) * | 2004-04-13 | 2005-10-13 | Funai Electric Co., Ltd. | Image forming apparatus and thermal transfer printer |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090057985A1 (en) * | 2007-08-29 | 2009-03-05 | Avision Inc. | Paper pick-up mechanism and feeder using the same |
US7946572B2 (en) * | 2007-08-29 | 2011-05-24 | Avision Inc. | Paper pick-up mechanism and feeder using the same |
US20110068533A1 (en) * | 2009-09-18 | 2011-03-24 | Thomas Sheng | Sheet transporting apparatus having gear assembly for mounting rotating shaft, and scanner and image processing apparatus using the same |
US20180088518A1 (en) * | 2016-09-29 | 2018-03-29 | Canon Kabushiki Kaisha | Driving device and image forming apparatus |
US10649386B2 (en) * | 2016-09-29 | 2020-05-12 | Canon Kabushiki Kaisha | Driving device and image forming apparatus |
CN108328390A (en) * | 2018-03-23 | 2018-07-27 | 深圳市领创精密机械有限公司 | A kind of coiled strip film synchronous conveying system |
Also Published As
Publication number | Publication date |
---|---|
JP2005194033A (en) | 2005-07-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU595044B2 (en) | Process cartridge and image forming apparatus using same | |
US10118795B2 (en) | Image forming apparatus provided with transmission mechanism for transmitting drive force to reconveying roller | |
US20050146090A1 (en) | Drive transmission mechanism and drive transmission mechanism for printer apparatus | |
US8157260B2 (en) | Roller module for an automatic document feeder | |
US8002278B2 (en) | Printing apparatus with planetary gear unit for resolving paper jam | |
US5155603A (en) | Apparatus for transferring documents in a facsimile | |
JP4687284B2 (en) | Paper feeding device and image forming apparatus | |
KR100211795B1 (en) | Driving device for subsidiary sheet feeding device of laser beam printer | |
US20050110205A1 (en) | Automatic document feeder for image forming apparatus | |
US9670014B2 (en) | Sheet feeding apparatus | |
US20070040322A1 (en) | Image generating apparatus | |
JPH08285034A (en) | Drive transmission mechanism | |
JP2019210084A (en) | Sheet conveying device and image forming device having the same, and sheet conveying method | |
JP2619959B2 (en) | Paper feeder | |
US20080169599A1 (en) | Automatic sheet feeder having a flexible element on one end of the pick shaft | |
JP2021187657A (en) | Sheet conveying device, feeding device and image forming device | |
KR100527186B1 (en) | Paper supplying apparatus of image forming equipment | |
JPH09171339A (en) | Image forming device | |
JP4419430B2 (en) | Image forming apparatus | |
JP3951306B2 (en) | Image forming apparatus | |
US8787815B2 (en) | Sheet conveying apparatus and image forming apparatus | |
JPH0730599Y2 (en) | Mechanism for preventing conveyance failure in paper feeder | |
JP2005320081A (en) | Rotating conveying member support structure and image forming device equipped with the same | |
JPH08268594A (en) | Paper feeder | |
JP2011081148A (en) | Damper device, separation/contact mechanism, fixing device, and image forming apparatus |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: FUNAI ELECTRIC CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SAWAI, KUNIO;REEL/FRAME:016156/0089 Effective date: 20041224 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |