Thermal transcription printer

Abstract: An improved thermal-transcription printer capable of printing on both sides of a sheet of paper (50) includes first and second transferring rollers (53, 54), first and second guide paths (73, 74), and a paper-ejection path (72). The paper (50) is turned over for printing on the reverse side, after the front is completely printed.

Description: The present invention relates to a thermal-transcription printer, and more particularly, though not exclusively, to a thermal-transcription printer which can print on both sides of a sheet of paper. As shown in Figure 1, a thermal-transcription printer is generally comprised of a platen drum 11 which is rotated by a predetermined driving source (not shown), an ink ribbon 20 provided over the platen drum 11, wound in one direction, a pair of paper-supply rollers 13 for supplying a sheet of paper 14 between the platen drum 11 and ink ribbon 20, a capstan roller 15 and a pinch roller 16 for transferring while pressing the paper sheet 14, and a recording head 10 installed to move up and down to press or release the ink ribbon 20. The ink ribbon 20 consists of a series of sections sequentially coated with pigments of yellow Y, magenta M, cyan Y and black B, as shown in Figure 2. The operation of the above thermal-transcription printer will now be described. First, the paper sheet 14 is transferred from a supply cassette 12 toward the platen drum 11 by the paper-supply rollers 13. When the paper sheet 14 reaches a printing position, the recording head 10 moves down and thermally presses the ink ribbon 20. Here, only the first color (e.g., yellow) of the ink ribbon 20 is printed. With the yellow printing thus completed, the paper sheet 14 is retreated by the reverse rotation of the capstan roller 15, the recording head 10 moves up, and the ink ribbon 20 rolls to place the section for the next color (e.g., magenta) in the printing position. When the paper sheet 14 stops in the printing position again, the recording head 10 moves down and thermally presses the ink ribbon 20. Thus, the magenta color is printed on the transferred paper 14. The cyan and black colors are superimposed on the paper 14 by repeating the above procedure. In the above conventional thermal-transcription printer, printing is restricted to one side of the paper. Therefore, to print on the other side, the same sheet should be fed again. As a result, the conventional thermal-transcription printer exhibits slowed printing and presents an inconvenience to the user. United States Patent No. 4,932,798 discloses a device for recording information on both sides of a recording sheet. The device comprises a sheet guidance surface positioned adjacent an underside of a print roller to feed a recording sheet between the print roller and a recording unit into a draw-in gap for printing information on a first side of the sheet and a sheet acceptance surface positioned between and underside of said print roller between the print roller and the sheet guidance surface for receiving the sheet and positioning the sheet for feeding into the draw-in gap for printing information of a second side of the sheet. The sheet acceptance surface comprises a planar surface arranged on an incline with the lower end being in the region between the print roller and the sheet guidance surface. United State patent No. 5,101,222 discloses a printer suitable for use with transparent, heat sensitive recording materials. The printer is arranged to allow contact of both sides of a sheet or recording material with a heated recording head, to allow for printing in different colors on each side of the transparent recording medium. It is an aim of preferred embodiments of the present invention is to provide a thermal-transcription printer for printing on both sides of a sheet of paper. According to the present invention, there is provided a thermal-transcription printer comprising: a platen drum rotated by a first driving source; a recording head positioned over said platen drum, having means for emitting heat in a predetermined pattern, and installed so as to move up and down so that said heat emitting means is brought into contact with said platen drum; an ink ribbon coated with sequential sections of predetermined color pigments and transferred between said recording head and said platen drum; first transferring means for laterally transferring a sheet of paper between said ink ribbon and said platen drum; second transferring means for repositioning the sheet of paper after one side of the paper sheet is completely printed and for laterally transferring the paper sheet between said platen drum and said ink ribbon printing on an opposite side of the paper sheet; and means for ejecting said paper sheet, wherein said first transferring means comprises: a capstan roller disposed at one side of said platen drum and rotated by a second driving source; a pinch roller for friction-rotating with said capstan roller; a pair of first transferring rollers installed at the other side of said platen drum and rotated by a third driving source; a paper-supply path for guiding said paper sheet between said capstan roller and said pinch roller; a first guide path for guiding said paper from said platen drum, and at the rear of which said first transferring rollers are installed; and a second guide path having one end which opens toward said capstan roller and the other end which communicates with said first guide path; and said second transferring means comprising: a paper-ejection path for ejecting said paper sheet from said capstan roller and said platen drum; said second guide path, wherein said end which communicates with said first guide path also communicates with said paper-ejection path, and said pinch roller; and a pair of second transferring rollers installed in said second guide path and rotated by a fourth driving source. Suitably, said first transferring means comprises: a capstan roller disposed at one side of said platen drum and rotated by a second driving source; a pinch roller for friction-rotating with said capstan roller; a pair of first transferring rollers installed at the other side of said platen drum and rotated by a third driving source; a paper-supply path for guiding said paper sheet between said capstan roller and said pinch roller; a first guide path for guiding said paper sheet from said platen drum, and at the rear of which said first transferring rollers are installed; and a second guide path having one end which opens toward said capstan roller and the other end which communicates with said first guide path. Suitably, said second transferring means comprises a paper-ejection path for ejecting said paper sheet from said capstan roller and said platen drum; a second guide path having one end which communicates with said paper-ejection path and the other which opens toward said capstan roller and said pinch roller; and a pair of second transferring rollers installed in said second guide path and rotated by a fourth driving source. Suitably, the printer further comprises a first sensor installed in front of said capstan roller, for sensing either end of said paper sheet; and a second sensor installed in front of said first transferring rollers, for sensing the trailing edge of said paper. A thermal-transcription printer according to the present invention enables both sides of a sheet of paper to be printed by turning the paper over through the first and second guide paths and the paper-ejection path. The present invention will become more apparent by describing in detail, by way of example only, a preferred embodiment thereof with reference to the attached drawings in which: Figure 1 is a schematic view of a conventional thermal-transcription printer; Figure 2 is a schematic view of an ink ribbon; and Figures 3-10 are operational diagrams of a thermal-transcription printer according to the present invention. Figure 3 schematically illustrates a thermal-transcription printer according to the present invention. Reference numeral 40 denotes a platen drum rotated by a first driving source (not shown). A recording head 30 is installed over the platen drum 40 so as to move up and down, and is provided with a heat emitting device (not shown) for emitting heat in a predetermined pattern. The recording head 30 descends to establish contact between the heat emitting device and platen drum 40. An ink ribbon 20 as described with reference to Figure 2 is provided over the platen drum 40 to be transferred between the recording drum 30 and the platen drum 40. There are further provided first transferring means for transferring a sheet of paper 50 back and forth between the ink ribbon 20 and platen drum 40, and second transferring means for transferring the paper sheet 50, which is turned over after the printing of one side is completed, back and forth between the platen drum 40 and ink ribbon 20. The first transferring means has a capstan roller 41 provided at one (rear) side of the platen drum 40 and rotated by a second driving source (not shown), a pinch roller 42 for friction-rotating with the capstan roller 41, a pair of first transferring rollers 53 and 54 installed at the other (front) side of the platen drum 40 and rotated by a third driving source (not shown), a paper-supply path 71 for guiding the paper sheet 50 between the capstan roller 41 and pinch roller 42, a first guide path 73 for guiding the paper from the platen drum 40 and having the first transferring rollers 53 and 54 at the rear thereof, and a second guide path 74 having one end which opens toward the capstan roller 41 and the other end which communicates with the first guide path 73. The second transferring means comprises a paper-ejection path 72 for ejecting the paper sheet 50 from the capstan roller 41 and platen drum 40 through the first guide path 73 and first transferring rollers 53 and 54, the second guide path 74, and a pair of second transferring rollers 55 and 56 installed in the second guide path 74 and rotated by a fourth driving source (not shown). The paper-supply and paper-ejection paths 71 and 72 and the first and second guide paths 73 and 74 are formed by first to fifth guide blocks 81-85. Meanwhile, a first sensor 61 for sensing either edge of the paper sheet 50 is installed adjacent to the capstan roller 41, and a second sensor 62 for sensing only the trailing edge of the paper sheet 50 is installed adjacent to the first transferring rollers 53 and 54. Reference numeral 23 denotes a color sensor for sensing the location of each of the various colors along the ink ribbon 20. The operation of the thermal-transcription printer as constituted above will be described. As shown in Figure 3, the paper sheet 50 is supplied between a pair of supply rollers 51 and 52 installed in front of the paper-supply path 71. When the first sensor 61 senses the leading edge of the paper sheet 50, the capstan roller 41 and first transferring roller 54 rotate counterclockwise. Thus, the paper sheet 50 is transferred along the first guide path 73 and paper-ejection path 72. While the paper sheet 50 is being transferred, the recording head 30 remains over the platen drum 40 and the ink ribbon 20 remains inactive. As shown in Figure 4, when the first sensor 61 senses the trailing edge of the paper sheet 50, the capstan roller 41 and first transferring roller 54 stop rotating. Then, the ink ribbon 20 rolls from a supply reel 22 to a take-up reel 21. When the color sensor 23 senses the leading edge of the yellow color Y during the rolling of the ink ribbon 20, the transfer of the ink ribbon stops. Then, the recording head 30 descends and thermally presses the ink ribbon 20. In the above state, as shown in Figure 5, the paper sheet 50 is retreated while the capstan roller 41 and transferring roller 55 rotate clockwise. Here, the paper sheet 50 is transferred between the capstan roller 41 and pinch roller 42, along the second guide path 74 and between the second transferring rollers 55 and 56. When the yellow color Y is completely printed on the paper sheet 50, the recording head 50 moves up and the transfer of the ink ribbon 20 stops, as shown in Figure 6. Then, the capstan roller 41 and second transferring roller 55 rotate counterclockwise again, and thus the paper sheet 50 is transferred clockwise. Here, the paper sheet 50 reaches the paper-ejection path 72 through the first guide path 73. When the first sensor 61 senses again the trailing edge of the paper sheet 50, the capstan roller 41 stops, thereby stopping the transfer of the paper sheet. Then, the ink ribbon 20 rolls, and when the sensor 23 senses the leading edge of the magenta color M, the transfer of the ink ribbon stops. Thereafter, the magenta, cyan and black colors are superimposed by printing on the paper sheet 50 while the paper sheet is manipulated in the same manner as during the yellow printing. When one side of the paper sheet 50 is completely printed, the sheet is transferred toward the paper-ejection path 72, as shown in Figure 7. Here, the transfer of the paper sheet 50 is performed until its trailing edge reaches the second transferring rollers 53 and 54, by the rotation of the second transferring rollers 53 and 54 and ejection rollers 57 and 58. When the second sensor 62 senses the trailing edge of the paper sheet 50, its transfer stops. Then, as shown in Figure 8, the paper sheet 50 is transferred clockwise by reversely rotating the first and second transferring rollers 53 & 54 and 55 & 56. Here, the paper sheet 50 is turned over while it passes through the second transferring rollers 55 and 56, second guide path 74, capstan roller 41 and first guide path 73. When the first sensor 61 senses the trailing edge of the paper sheet 50, its transfer stops. Then, the ink ribbon 20 rolls, and when the color sensor 23 senses the leading edge of the yellow color Y, the transfer of the paper sheet 50 stops. Thereafter, the recording head 30 descends to thermally press the ink ribbon 20. Then, while the capstan roller 41 and second transferring roller 55 rotate clockwise, the paper sheet 50 is transferred backward. Thus, the yellow color Y is printed on the rear side of the paper sheet 50. When the yellow color Y is completely printed, the capstan roller 41 is driven counterclockwise, and thus the paper sheet 50 is transferred to the initial printing position as shown in Figure 8. Then, the ink ribbon 20 is transferred, and when the color sensor 23 senses the leading edge of the magenta M, the transfer of the ink ribbon 20 stops. Thereafter, the recording head 30 moves down and thermally presses the ink ribbon 20. In the above state, as shown in Figure 9, the paper sheet 50 is transferred and the magenta color M is printed in the same manner as the yellow color Y was printed, and thus superimposed on the paper. Then, the cyan color C and black color B are each printed on the paper sheet 50 in the order described above. After the rear side of the paper sheet 50 is printed, as shown in Figure 10, the capstan roller 41, first transferring rollers 53 and 54 and ejection rollers 57 and 58 are driven, thereby ejecting the paper sheet. As described above, the thermal-transcription printer according to the present invention can print on both sides of a sheet of paper.

Claims: A thermal-transcription printer comprising: a platen drum (40) rotated by a first driving source; a recording head (30) positioned over said platen drum (40), having means for emitting heat in a predetermined pattern, and installed so as to move up and down so that said heat emitting means is brought into contact with said platen drum (40); an ink ribbon (20) coated with sequential sections of predetermined color pigments and transferred between said recording head (30) and said platen drum (40) ; first transferring means (41, 42, 53, 54, 71, 73, 74) for laterally transferring a sheet of paper (50) between said ink ribbon (20) and said platen drum (40); second transferring means (72, 55, 56) for repositioning the sheet of paper after one side of the paper sheet (50) is completely printed and for laterally transferring the paper sheet (50) between said platen drum (40) and said ink ribbon (20) for printing on an opposite side of the paper sheet; and means (41, 53, 54, 57, 58) for ejecting said paper sheet (50), wherein said first transferring means (41, 42, 53, 54, 71 73, 74) comprises: a capstan roller (41) disposed at one side of said platen drum (40) and rotated by a second driving source; a pinch roller (42) for friction-rotating with said capstan roller (41) ; a pair of first transferring rollers (53, 54) installed at the other side of said platen drum (40) and rotated by a third driving source; a paper-supply path (71) for guiding said paper sheet (50) between said capstan roller (41) and said pinch roller (42) ; a first guide path (73) for guiding said paper sheet (50) from said platen drum (40), and at the rear of which said first transferring rollers (53, 54) are installed; and a second guide path (74) having one end which opens toward said capstan roller (41) and the other end which communicates with said first guide path (73) ; and said second transferring means (72, 55, 56) comprising: a paper-ejection path (72) for ejecting said paper sheet (50) from said capstan roller (41) and said platen drum (40) ; said second guide path (74), wherein said end which communicates with said first guide path (73) also communicates with said paper-ejection path (72), and said pinch roller (42); and a pair of second transferring rollers (55, 56) installed in said second guide path and rotated by a fourth driving source. A thermal-transcription printer as claimed in Claim 1, further comprising: a first sensor (61) installed in front of said capstan roller (41), for sensing either end of said paper sheet (50); and a second sensor (62) installed in front of said first transferring rollers (53, 54), for sensing the trailing edge of said paper (50).

Inventors: PARK MOON-BAE, PARK, MOON-BAE
Applicants: SAMSUNG ELECTRONICS CO LTD, SAMSUNG ELECTRONICS CO., LTD.
Application year: 1996
Main classification: B41J3
IPC codes: B41J13, B41J3, B41J11, B41J2