JP3941115B2 - Paper feeding method of image forming apparatus - Google Patents

Description

  The present invention relates to a paper feeding method for an image forming apparatus.

  Conventionally, various paper feeding methods have been proposed for image forming apparatuses such as inkjet recording apparatuses (see, for example, Patent Document 1 and Patent Document 2).

  In Patent Document 1, a temporary print start position provided at a position easily visible from the outside of a printer and a paper feed start position are manually aligned, and then a temporary print start position, a print head, and a platen are set. The print start position of the paper without opening the printer cover by comparing and calculating the distance between the true print start position at a position opposite to and the preset one page length of the paper. A printer with a paper cueing function that can adjust the position to the true print start position is disclosed.

  Further, in Patent Document 2, in order to perform recording with a certain quality on sheets of different thicknesses, the recording head (printing head) is rotated around a predetermined rotation center, In the ink jet recording apparatus having a mechanism for adjusting the distance between the recording head, the distance is determined according to the distance between the rotated recording head and the paper from the paper feeding start position detected by the leading edge detection lever. A paper feeding method of an ink jet recording apparatus is disclosed in which the paper printing start position can be made constant regardless of the thickness of the paper by conveying the paper by the amount of paper transport.

  Conventionally, a thermal transfer printer is known as an example of an image forming apparatus. FIG. 16 is a perspective view showing the overall configuration of a conventional thermal transfer printer. FIG. 17 is a perspective view showing a state in which the ink ribbon cartridge is omitted from the conventional thermal transfer printer shown in FIG. FIG. 18 is a front view showing a stepping motor and each gear of the conventional thermal transfer printer shown in FIG. FIG. 19 is a plan view of an ink ribbon of the conventional thermal transfer printer shown in FIG. 21 to 30 show the conventional thermal transfer printer shown in FIG. First, the structure of a conventional thermal transfer printer will be described with reference to FIGS. 16 to 19 and FIG.

  As shown in FIGS. 16 to 19 and 21, the conventional thermal transfer printer includes a metal chassis 101, an ink ribbon cartridge 102, a take-up reel 103, and a metal feed roller 104 (see FIG. 21). A metal pressing roller 105 (see FIGS. 17 and 21) that presses the feed roller 104 with a predetermined pressing force, a pressing roller bearing 106 (see FIG. 17), and a bearing support plate 107 (see FIG. 17), Ribbon cue sensor 108 (see FIG. 21), print head 109 for printing, platen roller 110 (see FIG. 21) arranged to face the print head 109, motor bracket 111, and stepping motor 112, a rubber paper feed roller 113, a paper feed roller gear 114, a rubber paper discharge roller 115, and a paper discharge roller gear 11. A swingable swing gear 117, a swinging gear portion 118 in which the swinging gears 118a and 118b are interlocked, a feed roller gear 119, and a plurality of intermediate gears 120 to 124 (see FIG. 18). .

As shown in FIGS. 16 and 17, the chassis 101 has one side surface 101a, the other side surface 101b, and a bottom surface 101c. Further, the motor bracket 111 described above is attached to one side surface 101 a of the chassis 101. An insertion hole 1 for inserting the ink ribbon cartridge 102 is formed in the other side surface 101b of the chassis 101.
01d is provided. Further, as shown in FIGS. 16 and 21, the ink ribbon cartridge 102 includes a winding unit 102a and a supply unit 102b. Further, as shown in FIG. 21, a take-up bobbin 102c is rotatably disposed inside the take-up portion 102a of the ink ribbon cartridge 102. A supply bobbin 102d is rotatably disposed inside the supply unit 102b of the ink ribbon cartridge 102. An ink ribbon 102e is wound around the winding bobbin 102c and the supply bobbin 102d. As shown in FIG. 19, the ink ribbon 102e includes a Y (yellow) printing film 102f, an M (magenta) printing film 102g, a C (cyan) printing film 102h, and an OP film 102i. Moreover, the identification part 102j is provided between each film 102f-102i.

  Further, the take-up reel 103 has a function of taking up the ink ribbon 102e wound around the take-up bobbin 102c by engaging with a take-up bobbin 102c disposed inside the take-up portion 102a of the ink ribbon cartridge 102. Have. Further, as shown in FIG. 18, the gear 103a of the take-up reel 103 is arranged to mesh with the swinging gear 117 swinging.

  Further, as shown in FIG. 18, the feed roller 104 has a feed roller gear insertion portion 104a that is inserted into the feed roller gear 119. The feed roller 104 is rotatably supported by a feed roller bearing (not shown) attached to the chassis 101. Further, as shown in FIG. 17, the pressing roller 105 is rotatably supported by a pressing roller bearing 106. The pressing roller bearing 106 is attached to a bearing support plate 107. The bearing support plate 107 is provided on the inside of both side surfaces of the chassis 101. The bearing support plate 107 is disposed so as to press the pressing roller 105 against the feed roller 104.

  The ribbon cueing sensor 108 is attached to the bottom surface 101c of the chassis 101 as shown in FIG. The ribbon cueing sensor 108 has a function of detecting the identification unit 102j (see FIG. 19) of the ink ribbon 102e. The print head 109 includes a support shaft 109a, a head portion 109b, and a resin head cover 109c attached to the head portion 109b. As shown in FIG. 17, the print head 109 is attached to the inside of both side surfaces of the chassis 101 so as to be rotatable about a support shaft 109a. The platen roller 110 is rotatably supported by platen roller bearings (not shown) attached to both side surfaces of the chassis 101.

  Further, as shown in FIG. 18, a motor gear 112 a is attached to the shaft portion of the stepping motor 112 attached to the motor bracket 111. Further, the stepping motor 112 has a function as a drive source for driving the gear 103 a of the take-up reel 103, the paper feed roller gear 114, the paper discharge roller gear 116, and the feed roller gear 119.

Next, with reference to FIG. 18 and FIG. 21, the feeding operation of the paper 130 and the winding operation of the ink ribbon 102e of the conventional thermal transfer printer will be described. At the time of paper discharge (printing), as shown in FIG. 18, as the stepping motor 112 is driven, the motor gear 112a attached to the stepping motor 112 rotates in the direction of arrow B2 in FIG. 18 and 121, the feed roller gear 119 rotates in the direction of arrow D2 in FIG. As a result, the feed roller 104 rotates in the direction of arrow D2 in FIGS. 18 and 21 and conveys the sheet 130 in the printing direction (direction of arrow S2 in FIG. 21). At this time, the swingable swing gear 117 meshes with the gear 103a of the take-up reel 103, and rotates the gear 103a of the take-up reel 103 in the direction of arrow F2 in FIGS. Thereby, the take-up reel 10
3 is also rotated in the direction of arrow F2 in FIGS. 18 and 21, whereby the ink ribbon 102e wound around the take-up bobbin 102c and the supply bobbin 102d is taken up.

  At the time of paper feeding, first, as shown in FIG. 18, as the stepping motor 112 is driven, the motor gear 112a attached to the stepping motor 112 rotates in the direction of the arrow C2 in FIG. Accordingly, the feed roller gear 119 rotates in the direction of arrow E2 in FIG. As a result, the feed roller 104 rotates in the direction of arrow E2 in FIGS. 18 and 21 and conveys the paper 130 in the paper feeding direction (direction of arrow T2 in FIG. 21). At this time, the swingable swing gear 117 is not meshed with the gear 103a of the take-up reel 103, and the gear 103a of the take-up reel 103 does not rotate. As a result, the ink ribbon 102e wound around the take-up bobbin 102c and the supply bobbin 102d is not taken up during paper feeding.

  FIG. 20 is a flowchart for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. Next, a paper feeding method of a conventional thermal transfer printer will be described with reference to FIGS. 21 to 25 show a paper feeding method when the winding diameter of the ink ribbon 102e by the take-up bobbin 102c is small, and FIGS. 26 to 30 show the ink ribbon by the take-up bobbin 102c. A paper feeding method when the winding diameter of 102e is large is shown. First, as shown in the flowchart of FIG. 20, printing by the Y color printing film 102f of the ink ribbon 102e is started. In this case, first, in step S101, the stepping motor 112 is rotated by the number of steps P (constant). As a result, the feed roller 104 is rotated by the number of steps P (constant), whereby the sheet 130 is conveyed in the printing direction of the step number P (constant) (in the direction of arrow S2 in FIGS. Y-color (yellow) printing is performed. In step S102, the print head 109 is moved upward to the first paper feed path formation position. At this time, the sheet 130 is located at the print end position 140 shown in FIGS. Thereafter, in step S103, the ink ribbon 102e is cued by rotating the stepping motor 112, and the paper 130 is conveyed to the paper feed start positions 151 and 152 shown in FIGS. At this time, in step S104, it is determined whether or not the ribbon cueing sensor 108 has been turned on by detecting the identification portion 102j of the ink ribbon 102e. If it is determined in step S104 that the ribbon cueing sensor 108 has been turned on, the process proceeds to the next step S105. If the ribbon cueing sensor 108 has not been turned on, this determination is made. Repeated.

  When the paper 130 is transported from the print end position 140 to the paper feed start positions 151 and 152, the winding diameter of the ink ribbon 102e wound around the take-up bobbin 102c is large at the end of winding of the ink ribbon 102e (see FIG. 26). Therefore, the number of times the take-up reel 103 rotates to take up the equivalent ink ribbon 102e is reduced as compared with the time when the winding diameter is small (see FIG. 21). Therefore, when the winding diameter shown in FIG. 26 is large, the number of rotations of the feed roller 104 that rotates in synchronization with the take-up reel 103 is reduced as compared with the case where the winding diameter shown in FIG. 21 is small. Therefore, when the winding diameter shown in FIG. 26 is large, the distance by which the paper 130 is conveyed from the print end position 140 to the paper feed start position 152 is shorter than when the winding diameter shown in FIG. 21 is small. . As a result, as shown in FIGS. 22 and 27, at the paper feed start position 151 at the start of winding with a small winding diameter and at the paper feed start position 152 at the end of winding with a large winding diameter, Variation occurs.

Next, in step S105, as the first paper feeding step, the paper feeding start positions 151 and 152 shown in FIGS. 22 and 27 are sent to the print head lower insertion positions 161 and 162 shown in FIGS. 23 and 28, respectively. Roller 104 is fed in the paper feeding direction (FIGS. 23 and 2).
8 (in the direction of arrow T2), the stepping motor 112 is rotated by the number of steps Z (constant). Further, in step S106, as shown in FIGS. 24 and 29, the print head 109 is moved downward to the second paper feed path forming position. Thereafter, in step S107, the number of steps m (variable) of the stepping motor 112 operated until the ribbon cueing sensor ON at the time of ribbon cueing is detected, and the feed roller is fed to the paper cueing position (see FIG. 25 and FIG. 25). The stepping motor 112 rotates in the direction of arrow T2 in FIG. 30 by the number of steps (P + m−Z). As a result, the paper 130 is conveyed to the paper cueing positions 171 and 172 shown in FIGS. As a result, preparation for printing with the M (magenta) printing film 102g of the next ink ribbon 102e is completed.
JP-A-5-208529 JP 7-117296 A

  The conventional thermal transfer printer shown in FIGS. 16 to 30 is shown in FIGS. 22 and 27 when the winding diameter of the ink ribbon 102e is small (at the start of winding) and when the winding diameter is large (at the end of winding). As described above, due to the difference in the winding diameter of the ink ribbon 102e, the feed start position 151 at the start of winding and the feed start position 152 at the end of winding vary. Therefore, the feed roller 104 is rotated in the sheet feeding direction (in the direction of arrow T2 in FIGS. 23 and 28) by the number of steps Z (constant) of the stepping motor 112, and the sheet 130 is moved from the sheet feeding start positions 151 and 152, respectively. When transported to the print head lower insertion positions 161 and 162, as shown in FIGS. 23 and 28, the print head lower insertion position 161 and the print head lower insertion position 162 are not uniform. In this case, as shown in FIG. 24, when the second paper feed path is formed by moving the print head 109 toward the platen roller 109, the print head 109 and the paper 130 may not be in proper contact. . In that case, there is a problem that operation failure such as a paper jam may occur.

  Further, in the printer with a paper cueing function disclosed in Patent Document 1, if there is a variation in the paper feeding start position, the provisional print start position provided at a position that is easily visible from the outside of the printer is supplied. Since the paper start position is manually adjusted, there is an inconvenience that the temporary print start position and the paper feed start position are likely to be shifted. For this reason, when the paper is transported from the temporary print start position to the true print start position, a malfunction such as a paper jam may occur due to the paper and the print head contacting at an inappropriate position. There is a problem that there is.

  Further, the ink jet recording apparatus disclosed in Patent Document 2 has a problem that the number of parts increases by the amount of the tip detection lever because the paper feed start position is regulated by the tip detection lever.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to suppress the occurrence of malfunction such as a paper jam and to increase the number of parts. It is an object of the present invention to provide a sheet feeding method for an image forming apparatus that can be suppressed.

According to a first aspect of the present invention, a sheet feeding method for an image forming apparatus includes a step of performing printing while conveying a sheet in a printing direction by rotating a stepping motor by a preset number of steps P, and printing. By separating the head from the platen roller, the step of forming the first paper feed path, and after printing, the paper and the ink ribbon are conveyed in the printing direction until the ink ribbon identification portion is detected by the sensor. In the paper feeding method of the image forming apparatus including the step of cueing the ink ribbon and transporting the paper to a paper feeding start position, after printing, until the ink ribbon identification unit is detected by the sensor Detects the number of steps m of the stepping motor required to transport the paper in the printing direction and sets the number of steps set in advance And a step number P, on the basis of the step number m of the stepping motor based on the detection of the identification portion of the ink ribbon by the sensor, the step number (P + m-Y) component only, the head portion of the print head to the paper from the starting position a first sheet feeding step for conveying the sheet feeding direction along a first feed path under Katama of the head cover projecting downward from, after the first sheet feeding step, moving the print head to the platen roller side To form the second paper feed path and rotate the stepping motor by a preset number of steps Y, so that the second paper feed path from the position near the bottom of the print head to the paper cue position And a second sheet feeding step for conveying the sheet in the sheet feeding direction.

  In the sheet feeding method of the image forming apparatus according to the first aspect, as described above, the step number Y (constant) and the step number P (constant) preset in the stepping motor, and the ink ribbon identification unit by the sensor Based on the step number m (variable) of the stepping motor based on the detection of the sheet, the sheet is conveyed in the sheet feeding direction from the sheet feeding start position to a position near the lower part of the print head by the number of steps (P + m−Y). Thus, even when there is a variation in the paper feed start position, the paper can always be conveyed to the same position near the lower part of the print head. Thus, when the print head is moved downward to form the second paper feed path after the paper is conveyed to the vicinity of the lower portion of the print head, the print head and the paper can always be brought into contact at the same position. As a result, it is possible to prevent malfunctions such as paper jams due to the print head not contacting the paper or contacting the paper at an inappropriate position, and variations in the paper position. Since there is no need to separately provide a member for regulating the number of parts, it is possible to suppress an increase in the number of parts. Further, according to the step number m (variable) of the stepping motor based on the detection of the ink ribbon identification part by the sensor, the number of steps (P + m−Y) from the paper feed start position to the position near the lower part of the print head. By conveying in the paper feeding direction, the sheet is moved to a position near the lower part of the print head by the step number m (variable) of the stepping motor and the preset step number P (constant) and step number Y (constant). The number of steps of the stepping motor corresponding to the transport distance can be easily calculated. Further, after the first paper feed step, the print head is moved to the platen roller side to form the second paper feed path, so that the paper is always placed at the same position near the lower portion of the print head by the first paper feed step. Since the second paper feed path can be formed in the transported state, the print head and the paper can be easily brought into contact at the same position when the second paper feed path is formed.

The paper feeding method of the image forming apparatus according to the second aspect of the present invention includes a step of performing printing by the print head while conveying the paper and the ink ribbon in the printing direction by the printing range, and identifying the ink ribbon after printing. The paper and the ink ribbon are transported in the printing direction until the ink is detected by the sensor, and the ink ribbon is cueed and the paper is transported to the paper feed start position. There distance amount corresponding to the conveying distance of the sheet to be detected, the first sheet transport to the paper feeding direction under Katama of the head cover projecting the sheet below the head portion of the print head from the paper feed start position A paper step, and then a second paper feeding step for conveying the paper by a predetermined amount in the paper feeding direction from a position near the bottom of the print head to the paper cueing position. Provided with a door.

In the sheet feeding method of the image forming apparatus according to the second aspect, as described above, from the sheet feeding start position by the distance corresponding to the sheet transport distance until the ink ribbon identification unit is detected by the sensor. By transporting the paper in the paper feeding direction to a position near the lower part of the print head, the paper can always be transported to the same position near the lower part of the print head, even if the feed start position varies. Accordingly, when the print head is moved downward in order to form a paper feed path after the paper is conveyed to the vicinity of the lower portion of the print head, the print head and the paper can always be brought into contact at the same position. As a result, the print head and the paper are not in contact, or
It is possible to suppress malfunctions such as paper jams due to contact at an inappropriate position, and it is not necessary to provide a separate member for regulating variation in the paper position. The increase can be suppressed.

  In the paper feeding method of the image forming apparatus according to the second aspect, preferably, the first paper feeding step is the stepping required for transporting the paper in the printing direction until the ink ribbon identification unit is detected by the sensor. A step of detecting the number of steps m of the motor, and a step of conveying the sheet in the sheet feeding direction from the sheet feeding start position to a position near the lower portion of the print head by a distance corresponding to the number of steps m of the stepping motor. According to this configuration, the number of steps of the stepping motor corresponding to the distance for transporting the paper to the position near the lower portion of the print head can be easily calculated based on the number of steps m (variable) of the stepping motor.

  In the sheet feeding method of the image forming apparatus according to the second aspect, preferably, the step of performing the printing is performed while the sheet is conveyed in the printing direction by rotating the stepping motor by a preset number of steps P. The second paper feeding step includes a step of conveying the paper in the paper feeding direction to the paper cueing position by rotating the stepping motor by a preset number of steps Y. In the paper step, the paper is fed by the number of steps (P + m−Y) based on the number of steps m of the stepping motor based on the detection of the identification part of the ink ribbon by the sensor, and the number of steps P and Y set in advance. A step of conveying in a paper feeding direction from a start position to a position near the lower portion of the print head. With this configuration, the sheet is transported to a position near the lower portion of the print head by the step number m (variable) of the stepping motor and the preset step number P (constant) and step number Y (constant). The number of stepping motor steps corresponding to the distance can be calculated more easily.

  In the paper feeding method of the image forming apparatus according to the second aspect, preferably, the first paper feeding path is formed by separating the print head from the platen roller prior to the first paper feeding step; And a step of forming a second paper feed path by moving the print head to the platen roller side after the first paper feed step. With this configuration, the second paper feed path can be formed while the paper is always conveyed to the same position in the vicinity of the lower portion of the print head by the first paper feed step. The print head and the paper can be easily brought into contact at the same position during the formation.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing the overall configuration of a thermal transfer printer according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state where the ink ribbon cartridge is omitted from the thermal transfer printer according to the embodiment of the present invention shown in FIG. FIG. 3 is a front view showing the stepping motor and each gear of the thermal transfer printer according to the embodiment of the present invention shown in FIG. FIG. 4 is a plan view of the ink ribbon of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 6 to 15 are views showing the thermal transfer printer according to the embodiment of the present invention shown in FIG. First, the structure of a thermal transfer printer according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, a case where the present invention is applied to a thermal transfer printer which is an example of an image forming apparatus will be described.

As shown in FIGS. 1 to 3 and 6, a thermal transfer printer according to an embodiment of the present invention includes a metal chassis 1, an ink ribbon cartridge 2, a take-up reel 3, and a metal feed roller 4 ( 6), a metal pressing roller 5 (see FIGS. 2 and 6) that presses the feed roller 4 with a predetermined pressing force, a pressing roller bearing 6 (see FIG. 2), and a bearing support plate 7 (see FIG. 6). 2), a ribbon cue sensor 8 (see FIG. 6), a print head 9 for performing printing, a platen roller 10 (see FIG. 6) arranged to face the print head 9, and a motor bracket 11, a stepping motor 12, a rubber paper feed roller 13, a paper feed roller gear 14, a rubber paper discharge roller 15, a paper discharge roller gear 16, a swingable swing gear 17, and a swing Gears 18a and 18b A swing gear portion 18 for moving includes a feed roller gear 19, a plurality of intermediate gears 20 to 24 (refer to FIG. 3). The ribbon cue sensor 8 is an example of the “sensor” in the present invention.

  As shown in FIGS. 1 and 2, the chassis 1 has one side surface 1a, the other side surface 1b, and a bottom surface 1c. Further, the motor bracket 11 described above is attached to one side surface 1 a of the chassis 1. An insertion hole 1 d for inserting the ink ribbon cartridge 2 is provided on the other side surface 1 b of the chassis 1. As shown in FIGS. 1 and 6, the ink ribbon cartridge 2 includes a winding unit 2 a and a supply unit 2 b. Further, as shown in FIG. 6, a take-up bobbin 2c is rotatably disposed inside the take-up portion 2a of the ink ribbon cartridge 2. A supply bobbin 2d is rotatably disposed inside the supply unit 2b of the ink ribbon cartridge 2. An ink ribbon 2e is wound around the take-up bobbin 2c and the supply bobbin 2d. As shown in FIG. 4, the ink ribbon 2e includes a Y (yellow) printing film 2f, an M (magenta) printing film 2g, a C (cyan) printing film 2h, and an OP film 2i. Moreover, the identification part 2j is provided between each film 2f-2i. The ink ribbon 2e can print 40 sheets of paper.

  The take-up reel 3 has a function of taking up the ink ribbon 2e wound around the take-up bobbin 2c by engaging with a take-up bobbin 2c disposed inside the take-up portion 2a of the ink ribbon cartridge 2. Have. As shown in FIG. 3, the gear 3 a of the take-up reel 3 is arranged so as to mesh with the swinging gear 17 swinging.

  Further, as shown in FIG. 3, the feed roller 4 has a feed roller gear insertion portion 4 a that is inserted into the feed roller gear 19. The feed roller 4 is rotatably supported by a feed roller bearing (not shown) attached to the chassis 1. As shown in FIG. 2, the pressing roller 5 is rotatably supported by a pressing roller bearing 6. The pressing roller bearing 6 is attached to a bearing support plate 7. The bearing support plate 7 is provided on the inside of both side surfaces of the chassis 1. Further, the bearing support plate 7 is disposed so as to press the pressing roller 5 against the feed roller 4.

  The ribbon cueing sensor 8 is attached to the bottom surface 1c of the chassis 1 as shown in FIG. The ribbon cue sensor 8 has a function of detecting the identification unit 2j (see FIG. 4) of the ink ribbon 2e. The print head 9 includes a support shaft 9a, a head portion 9b, and a resin head cover 9c attached to the head portion 9b. As shown in FIG. 2, the print head 9 is attached to the inside of both side surfaces of the chassis 1 so as to be rotatable about a support shaft 9a. The platen roller 10 is rotatably supported by platen roller bearings (not shown) attached to both side surfaces of the chassis 1.

  As shown in FIG. 3, a motor gear 12 a is attached to the shaft portion of the stepping motor 12 attached to the motor bracket 11. Further, the stepping motor 12 has a function as a drive source for driving the gear 3 a of the take-up reel 3, the paper feed roller gear 14, the paper discharge roller gear 16, and the feed roller gear 19.

Next, the paper 30 feeding operation and the ink ribbon 2e winding operation of the thermal transfer printer according to the embodiment of the present invention will be described with reference to FIGS. At the time of paper discharge (printing), first, as shown in FIG. 3, the motor gear 12a attached to the stepping motor 12 rotates in the direction of arrow B1 in FIG. Through the gears 20 and 21, the feed roller gear 19 rotates in the direction of arrow D1 in FIG. As a result, the feed roller 4 rotates in the direction of arrow D1 in FIGS. 3 and 6 and conveys the paper 30 in the printing direction (in the direction of arrow S1 in FIG. 6). At this time, the swingable swing gear 17 meshes with the gear 3a of the take-up reel 3 and rotates the gear 3a of the take-up reel 3 in the direction of arrow F1 in FIGS. As a result, the take-up bobbin 2c engaged with the take-up reel 3 also rotates in the direction of the arrow F1 in FIGS. 3 and 6, whereby the ink ribbon 2e wound around the take-up bobbin 2c is taken up.

  At the time of paper feeding, first, as shown in FIG. 3, as the stepping motor 12 is driven, the motor gear 12a attached to the stepping motor 12 rotates in the direction of the arrow C1 in FIG. Thus, the feed roller gear 19 rotates in the direction of arrow E1 in FIG. As a result, the feed roller 4 rotates in the direction of arrow E1 in FIGS. 3 and 6 and transports the paper 30 in the paper feeding direction (in the direction of arrow T1 in FIG. 6). At this time, the swingable swing gear 17 is not meshed with the gear 3a of the take-up reel 3, and the gear 3a of the take-up reel 3 does not rotate. As a result, the ink ribbon 2e wound around the take-up bobbin 2c and the supply bobbin 2d is not taken up during paper feeding.

  FIG. 5 is a flowchart for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. Next, a paper feeding method of the thermal transfer printer according to the embodiment of the present invention will be described with reference to FIGS. 6 to 10 show a paper feeding method when the winding diameter of the ink ribbon 2e by the take-up bobbin 2c is small. FIGS. 11 to 15 show the ink ribbon by the take-up bobbin 2c. A paper feeding method when the winding diameter of 2e is large is shown. First, as shown in the flowchart of FIG. 5, printing of the ink ribbon 2e by the Y-color printing film 2f is started. In this case, first, in step S1, the stepping motor 12 is rotated by step P (constant). Thus, the feed roller 4 is rotated by the number of steps P (constant), whereby the paper 30 is conveyed in the printing direction of the number of steps P (constant) (in the direction of the arrow S1 in FIGS. 6 and 11) and on the paper 30. Y-color (yellow) printing is performed. In step S2, the print head 9 is moved upward to the first paper feed path formation position. At this time, the paper 30 is located at the print end position 40 shown in FIGS. Thereafter, in step S3, the stepping motor 12 is rotated to cue the ink ribbon 2e, and the paper 30 is conveyed to the paper feed start positions 51 and 52 shown in FIGS. At this time, in step S4, it is determined whether or not the ribbon cueing sensor 8 has been turned on by detecting the identification portion 2j of the ink ribbon 2e. If it is determined in step S4 that the ribbon cue sensor 8 has been turned on, the process proceeds to the next step S5. If the ribbon cue sensor 8 has not been turned on, this determination is made. Repeated.

  When the paper 30 is transported from the print end position 40 to the paper feed start positions 51 and 52, at the end of winding of the ink ribbon 2e (see FIG. 11), the winding diameter of the ink ribbon 2e wound around the winding bobbin 2c is large. Therefore, the number of rotations of the take-up reel 3 to take up the equivalent ink ribbon 2e is reduced as compared with the time when the winding diameter is small (see FIG. 6). For this reason, when the winding diameter shown in FIG. 11 is large, the number of rotations of the feed roller 4 that rotates in synchronization with the take-up reel 3 is reduced as compared with the case where the winding diameter shown in FIG. 6 is small. Therefore, when the winding diameter shown in FIG. 11 is large, the distance by which the paper 30 is transported from the print end position 40 to the paper feed start position 52 becomes shorter than when the winding diameter shown in FIG. 6 is small. . As a result, as shown in FIGS. 7 and 12, the paper feed start position 51 of the paper 30 at the start of winding with a small winding diameter and the paper feed start position 52 of the paper 30 at the end of winding with a large winding diameter Variation occurs.

  Next, in step S5, as the first paper feed step, the number of steps m (variable) of the stepping motor 12 that has been operated until the ink ribbon cue sensor ON at the time of cueing the ink ribbon 2e is detected, and the paper feed is started. The number of steps of the stepping motor 12 from the positions 51 and 52 to the feed head lower insertion positions 61 and 62 shown in FIGS. 8 and 13 in the paper feeding direction (the direction of the arrow T1 in FIGS. 8 and 13), respectively ( Rotate by P + m−Y). Further, in step S6, as shown in FIGS. 9 and 14, the print head 9 is moved downward to the second paper feed path forming position. Thereafter, in step S7, as a second paper feed step, the feed roller is fed in the paper feed direction (from FIG. 9 and FIG. 14) from the print head lower insertion positions 61 and 62 to the paper cue positions 71 and 72 shown in FIGS. The stepping motor 12 is rotated by the number of steps Y (constant) in the direction of arrow T1). As a result, the paper 30 is conveyed to the paper cueing positions 71 and 72 shown in FIGS. As a result, preparation for printing with the M (magenta) printing film 2g of the next ink ribbon 2e is completed.

  In the present embodiment, as described above, the number of steps Y (constant) and the number of steps P (constant) set in advance in the stepping motor 12 and the detection of the identification unit 2j of the ink ribbon 2e by the ribbon cue sensor 8 are based. Depending on the number of steps m (variable) of the stepping motor 12, the sheet 30 is conveyed in the sheet feeding direction from the sheet feeding start position to the print head lower insertion position by the number of steps (P + m−Y). Even when the start position varies, the paper 30 can always be conveyed to the same print head lower insertion position. Thus, when the head portion 9b of the print head 9 is moved downward in order to form the second paper feed path after the sheet is conveyed to the print head lower insertion position, the print head 9 is attached to the head portion 9b. The head cover 8c and the paper 30 can be always brought into contact with each other at the same position. As a result, it is possible to suppress the occurrence of malfunction such as a paper jam caused by the head portion 9b of the print head 9 and the paper 30 not contacting each other or contacting at an inappropriate position. In addition, since it is not necessary to separately provide a member for regulating variation in the paper position, it is possible to suppress an increase in the number of parts.

  Further, in the present embodiment, the number of steps (P + m−Y) is set from the paper feed start position according to the number of steps m of the stepping motor 12 based on the detection of the identification unit 2j of the ink ribbon 2e by the cue sensor 8. By transporting in the paper feeding direction to a position near the lower portion of the head portion 9b of the print head 9, the number of steps m (variable) of the stepping motor 12, preset number of steps P (constant) and step Y (constant). Thus, the number of steps of the stepping motor 12 corresponding to the distance for transporting the paper 30 to the print head lower insertion position can be easily calculated.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and all modifications within the meaning and scope equivalent to the scope of claims for patent are included.

  For example, in the above embodiment, the thermal transfer printer is shown as an example of the image forming apparatus. However, the present invention is not limited to this, and the present invention is applicable to other image forming apparatuses other than the thermal transfer printer as long as the image forming apparatus is used. .

1 is a perspective view showing an overall configuration of a thermal transfer printer according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating a state where an ink ribbon cartridge is omitted from the thermal transfer printer according to the embodiment of the present invention illustrated in FIG. 1. FIG. 2 is a front view showing a stepping motor and gears of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. It is a top view of the ink ribbon of the thermal transfer printer by one Embodiment of this invention shown in FIG. 2 is a flowchart for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. FIG. 2 is a cross-sectional view for explaining a paper feeding method of the thermal transfer printer according to the embodiment of the present invention shown in FIG. 1. It is the perspective view which showed the whole structure of the thermal transfer printer by an example of the past. FIG. 17 is a perspective view showing a state where an ink ribbon cartridge is omitted from the conventional thermal transfer printer shown in FIG. 16. It is the front view which showed the stepping motor and each gear of the conventional thermal transfer printer shown in FIG. It is a top view of the ink ribbon of the conventional thermal transfer printer shown in FIG. FIG. 17 is a flowchart for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16. FIG. 17 is a cross-sectional view for explaining a paper feeding method of the conventional thermal transfer printer shown in FIG. 16.

Explanation of symbols

2e Ink ribbon 2j Identification part 8 Ribbon cue sensor (sensor)
9 Print Head 10 Platen Roller 12 Stepping Motor 30 Paper 51, 52 Paper Feed Start Position 71, 72 Paper Cue Position

Claims (5)

The first feeding path is formed by rotating the stepping motor by a preset number of steps P to perform printing while conveying the paper in the printing direction and separating the print head from the platen roller. After the printing, until the ink ribbon identification unit is detected by the sensor, the paper and the ink ribbon are transported in the printing direction to cue the ink ribbon and feed the paper. A paper feeding method of an image forming apparatus comprising a step of transporting to a paper start position,
After the printing, the sensor detects the step number m of the stepping motor required for transporting the paper in the printing direction until the sensor detects the identification portion of the ink ribbon, and a preset number of steps. Based on Y and the number of steps P, and the number of steps m of the stepping motor based on the detection of the identification part of the ink ribbon by the sensor, the paper feeding is started by the number of steps (P + m−Y). a first sheet feeding step for conveying the sheet feeding direction along said first feed path under Katama of the head cover projecting downward from the head portion of the printing head from a position,
Forming a second paper feed path by moving the print head to the platen roller side after the first paper feed step;
By rotating the stepping motor by the preset number of steps Y, the paper is fed along the second paper feed path from the position near the bottom of the print head to the paper cueing position. A sheet feeding method for the image forming apparatus, comprising: a second sheet feeding step for conveying the sheet to the sheet. Printing with a print head while conveying paper and an ink ribbon in the printing direction for the printing range; and
After the printing, until the ink ribbon identification unit is detected by a sensor, the paper and the ink ribbon are transported in the printing direction to cue the ink ribbon and feed the paper. Conveying to the start position;
A head cover that protrudes below the paper feed start position from the paper feed start position by a distance corresponding to the paper transport distance until the sensor detects the ink ribbon identification portion . a first sheet feeding step for conveying the sheet feeding direction under Katama,
And a second sheet feeding step for conveying the sheet by a predetermined amount in the sheet feeding direction from a position near the lower portion of the print head to a sheet cueing position. Method. The first paper feeding step includes
Detecting the step number m of the stepping motor required for transporting the paper in the printing direction until the sensor detects the identification portion of the ink ribbon;
The method according to claim 2, further comprising a step of conveying the sheet in the sheet feeding direction from the sheet feeding start position to a position near the lower portion of the print head by a distance corresponding to the number of steps m of the stepping motor. A paper feeding method of the image forming apparatus. The step of performing the printing includes
Including rotating the stepping motor by a preset number of steps P to carry out printing while transporting the paper in the printing direction;
The second paper feeding step includes
Transporting the paper in the paper feeding direction to the paper cue position by rotating the stepping motor by a preset number of steps Y,
The first paper feeding step includes
Based on the step number m of the stepping motor based on the detection of the identification part of the ink ribbon by the sensor, the step number P and the step number Y set in advance, the sheet is fed by the number of steps (P + m−Y). The sheet feeding method of the image forming apparatus according to claim 3, further comprising a step of transporting in the sheet feeding direction from a sheet feeding start position to a position near a lower portion of the print head. Forming the first paper feed path by separating the print head from the platen roller prior to the first paper feed step;
5. The image according to claim 2, further comprising a step of forming a second paper feed path by moving the print head to the platen roller side after the first paper feed step. A paper feeding method of the forming apparatus.

Images