DRIVING MECHANISM FOR PHOTO PRINTER

Abstract

Provided is a driving mechanism for a photo printer, the photo printer having a frame for accommodating paper therein and a platen roller coupled to the frame to transfer paper, and the driving mechanism includes: a motor for providing a rotary force to the platen roller; a motor pinion disposed on one side of the frame to output the rotary force of the motor; at least one or more reduction gears coupled to a side wall of the frame to reduce the rotary force of the motor pinion; a final gear coupled to the platen roller to receive the reduced rotary force from the reduction gears; and a pressurizing member for elastically pressurizing the reduction gears against the side wall of the frame.

Claims

1. A driving mechanism for a photo printer, the photo printer having a frame for accommodating paper therein and a platen roller coupled to the frame to transfer paper, the driving mechanism comprising: a motor for providing a rotary force to the platen roller; a motor pinion disposed on one side of the frame to output the rotary force of the motor; at least one or more reduction gears coupled to a side wall of the frame to reduce the rotary force of the motor pinion; a final gear coupled to the platen roller to receive the reduced rotary force from the reduction gears; and a pressurizing member for elastically pressurizing the reduction gears against the side wall of the frame.

2. The driving mechanism according to claim 1, further comprising a fixing member fitted to an end periphery of a rotary shaft having the reduction gears fitted thereto to prevent the reduction gears from being separated from the rotary shaft, the pressurizing member being disposed between the reduction gears and the fixing member.

3. The driving mechanism according to claim 2, further comprising a washer between the pressurizing member and the reduction gears.

4. The driving mechanism according to claim 2, wherein the pressurizing member comprises any one of a coil spring, elastic rubber, and elastic sponge adapted to pass the rotary shaft of the reduction gears therethrough.

5. The driving mechanism according to claim 1, wherein the reduction gears comprise: a first reduction gear fitted to a first rotary shaft fixed to one side of the frame and having a driven gear engaging with the motor pinion; a second reduction gear fitted to a second rotary shaft adjacent to the first rotary shaft and having a driven gear engaging with a drive gear of the first reduction gear; a third reduction gear fitted to the first rotary shaft and having a driven gear engaging with a drive gear of the second reduction gear; a fourth reduction gear fitted to the second rotary shaft and having a driven gear engaging with a drive gear of the third reduction gear; and a fifth reduction gear fitted to a third rotary shaft adjacent to the second rotary shaft and having one side engaging with a drive gear of the fourth reduction gear and the other side engaging with the final gear.

6. The driving mechanism according to claim 5, wherein the pressurizing member is fitted to an end periphery of the first rotary shaft to elastically pressurize the first reduction gear and the second reduction gear against the side wall of the frame.

7. The driving mechanism according to claim 5, further comprising an interference prevention member disposed between the first reduction gear and the third reduction gear or between the second reduction gear and the fourth reduction gear.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0033] FIG. 1 is a sectional view showing a conventional photo printer.

[0034] FIGS. 2 to 3 show a driving mechanism for the conventional photo printer of FIG. 1.

[0035] FIGS. 4 and 5 show a driving mechanism for a photo printer according to an embodiment of the present invention.

[0036] FIG. 6 shows an operating state of the driving mechanism for a photo printer according to the embodiment of the present invention.

[0037] FIG. 7 shows a driving mechanism for a photo printer according to another embodiment of the present invention.

MODE FOR INVENTION

[0038] Hereinafter, an explanation on a configuration and an operation of a photo printer according to an embodiment of the present invention will be in detail given with reference to the attached drawing.

[0039] As shown in FIGS. 4 and 5, a photo printer 1 according to the present invention includes a frame F for accommodating paper therein and a feed roller disposed in the frame F to feed the paper forward.

[0040] A paper accommodating part 10 is disposed between both side walls of the frame F to stack the paper therein.

[0041] According to the present invention, further, the feed roller includes a pickup roller 11 located protrudingly from a bottom surface of the paper accommodating part 10 and a platen roller (See a reference symbol R2 of FIG. 1) coupled to the frame F to discharge the paper fed from the pickup roller 11 forward.

[0042] According to the present invention, also, the photo printer includes a thermal printing head disposed above the platen roller R2 to apply heat to the paper.

[0043] Now, an explanation on a driving mechanism for transferring the paper according to the present invention will be in detail given. As shown, the driving mechanism includes a motor M, a motor pinion 21, first to fifth reduction gears 22 to 26, and a final gear 27.

[0044] The motor pinion 21 is coupled to the motor M, and each of the first to fifth reduction gears 22 to 26 has a shape of a double gear having double diameters. Further, the final gear 27 is fitted to a shaft of the platen roller R2. According to the present invention, also, the motor pinion 21 and the first to fourth reduction gears 22 to 25 are spur gears, and the fifth reduction gear 26 and the final gear 27 are helical gears.

[0045] A rotary force of the motor M is transferred to the motor pinion 21, and the motor pinion 21 engages with the driven gear 22 of the first reduction gear. Next, a drive gear 22a of the first reduction gear engages with the driven gear 23 of the second reduction gear, and a drive gear 23a of the second reduction gear engages with the driven gear 24 of the third reduction gear. After that, a drive gear 24a of the third reduction gear engages with the driven gear 25 of the fourth reduction gear, and a drive gear 25a of the fourth reduction gear engages with the driven gear 26 of the fifth reduction gear. Sequentially, a drive gear 26a of the fifth reduction gear engages with the final gear 27, so that the rotary force of the motor M is transferred to the platen roller R2.

[0046] On the other hand, the first reduction gears 22 and 22a and the third reduction gears 24 and 24a are fitted to a first rotary shaft SH1. In the same manner as above, the second reduction gears 23 and 23a and the fourth reduction gears 25 and 25a are fitted to a second rotary shaft SH2.

[0047] If two or more reduction gears are fitted to one rotary shaft, like this, movements in an axial direction occur during the rotation of the reduction gears so that contact and separation between the adjacent reduction gears occur repeatedly, thereby generating impact sounds and vibrations from the reduction gears.

[0048] So as to prevent the contact and separation between the adjacent reduction gears fitted to the same rotary shaft from occurring repeatedly, the driving mechanism according to the present invention further includes a pressurizing member for elastically pressurizing the reduction gears against the side wall of the frame. In detail, the pressurizing member pressurizes the reduction gears against the side wall of the frame F to prevent the adjacent reduction gears from being separated from each other, so that the occurrence of the impact sounds and vibrations can be prevented.

[0049] According to the present invention, the pressurizing member is a coil spring 42 fitted to the first rotary shaft SH1. In more detail, the first reduction gears 22 and 22a, the third reduction gears 24 and 24a, and the coil spring 42 are fitted to the first rotary shaft SH1. The coil spring 42 serves to elastically pressurize the first reduction gears 22 and 22a and the third reduction gears 24 and 24a against the side wall of the frame F, thereby preventing the reduction gears from being separated from each other.

[0050] At this time, if the coil spring 42 comes into direct contact with the third reduction gears 24 and 24a, friction occurs during the rotation of the third reduction gears 24 and 24a, and so as to gently rotate the third reduction gears 24 and 24a, a washer 41 is disposed between the third reduction gears 24 and 24a and the coil spring 42. The washer 41 is made of a material having a small frictional force, like a metal material, and has a shape of a ring having a through hole adapted to pass the first rotary shaft SH1 therethrough.

[0051] After the first reduction gears 22 and 22a, the third reduction gears 24 and 24a, the washer 41, and the coil spring 42 are fitted sequentially to the first rotary shaft SH1, further, a snap ring 43 as a fixing member for fixing the fitted parts to the first rotary shaft SH1 is fitted to the first rotary shaft SH1, thereby preventing the fitted parts from being separated from the first rotary shaft SH1. The snap ring 43 includes a generally C or E ring.

[0052] Now, an operating state of the driving mechanism according to the present invention will be explained with reference to FIG. 6.

[0053] As shown, the first reduction gears 22 and 22a and the third reduction gears 24 and 24a are fitted to the first rotary shaft SH1 in parallel relation with each other. As mentioned above, the length of the first rotary shaft SH1 is greater than the sum of the widths of the first reduction gears 22 and 22a and the third reduction gears 24 and 24a so as to improve their assembly. As the coil spring 42 is fitted to one end periphery of the first rotary shaft SH1, however, the first reduction gears 22 and 22a and the third reduction gears 24 and 24a are always pressurized elastically against the side wall of the frame F, so that their left and right movements can be minimized during their rotation. Accordingly, the first reduction gears 22 and 22a always come into contact with the frame F, and the third reduction gears 24 and 24a always come into contact with the first reduction gears 22 and 22a, thereby preventing the first reduction gears 22 and 22a and the third reduction gears 24 and 24a from being repeatedly contacted and separated to avoid their collision. In detail, noise and vibrations, which occur when the first reduction gears 22 and 22a collide against the frame F and when the third reduction gears 24 and 24a collide against the first reduction gears 22 and 22a, can be prevented.

[0054] FIG. 7 shows a driving mechanism for a photo printer according to another embodiment of the present invention, and in this case, the pressurizing member is constituted of cylindrical elastic rubber 44. In detail, the cylindrical elastic rubber 44 is fitted between the washer 41 and the snap ring 43. Of course, the cylindrical elastic rubber 44 has a through hole formed on a center thereof to pass the first rotary shaft SH1 therethrough.

[0055] According to the present invention, like this, only if the pressurizing member is fitted to the first rotary shaft SH1 to elastically pressurize the third reduction gears 24 and 24a against the side wall of the frame F, other known means may be used as the pressurizing member. Instead of the elastic rubber, for example, elastic sponge may be used as the pressurizing member.

[0056] The pressurizing member may be fitted to the end periphery of the second rotary shaft SH2. As well, the pressurizing member may be fitted to the end periphery of a third rotary shaft SH3 to which a reduction gear having a single axis is fitted. However, the rotary speeds of the reduction gears fitted to the first rotary shaft SH1 are faster than those of the reduction gears fitted to the second rotary shaft SH2, so that collision sounds and vibrations are generated more strongly. Accordingly, it is most effective that the pressurizing member is fitted to the first rotary shaft SH1. In addition to the end periphery of the first rotary shaft SH1, further, it is possible that the pressurizing member is fitted to a space between the first reduction gears 22 and 22a and the third reduction gears 24 and 24a and to a space between the side wall of the frame F and the first reduction gears 22 and 22a.

[0057] On the other hand, the first reduction gears 22 and 22a and the third reduction gears 24 and 24a are fitted to the first rotary shaft SH1, but they have to have no influence on each other. In the same manner as above, the second reduction gears 23 and 23a and the fourth reduction gears 25 and 25a are fitted to the second rotary shaft SH2, but they have to have no influence on each other.

[0058] According to the present invention, washers 31 and 32 as interference prevention members are provided to spatially separate the reduction gears fitted to the same shafts from each other, so that the reduction gears fitted to the same shafts SH1 and SH2 do not have any influence on each other.

[0059] The washers 31 and 32 take a shape of a ring made of a metal material and having a through hole formed at the center thereof to pass the first rotary shaft SH1 and the second rotary shaft SH2 therethrough.

[0060] The washers 31 and 32 are fitted to the reduction gears, especially, to the space between the plurality of reduction gears fitted to the first rotary shaft SH1 and to the space between the plurality of reduction gears fitted to the second rotary shaft SH2.

[0061] According to the present invention, the washer 31 is disposed between the first reduction gears 22 and 22a and the third reduction gears 24 and 24a rotatably fitted to the same shaft as each other.

[0062] In the same manner as above, the washer 32 is disposed between the second reduction gears 23 and 23a and the fourth reduction gears 25 and 25a rotatably fitted to the same shaft as each other.

[0063] In detail, the washer 31 is disposed between the first reduction gears 22 and 22a and the third reduction gears 24 and 24a, and even if the third reduction gears 24 and 24a rotate, they have no influence on the first reduction gears 22 and 22a adjacent thereto.

[0064] In the same manner as above, the washer 32 is disposed between the second reduction gears 23 and 23a and the fourth reduction gears 25 and 25a, and even if the fourth reduction gears 25 and 25a rotate, they have no influence on the second reduction gears 23 and 23a adjacent thereto.

[0065] Accordingly, the reduction gears rotate at set rotation ratios, while performing reduction in rotation, so that the paper can be transferred at a given transferring speed, thereby improving a quality of print.