JP4465894B2 - Printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer that prints characters used for, for example, guide signs and directions.
[0002]
[Prior art]
Conventionally, for example, a printer shown in FIG. 16 is known. In FIG. 16, 1 is a sprocket for feeding a sheet, 2 is a platen roller, 3 is a thermal head, and 4 is a sheet roll around which the sheet is wound. The thermal head 3 is provided on a lid 5, and a ribbon cassette (not shown) is attached to the lid 5. The lid 5 is attached to the main body 7 so as to be rotatable about a shaft 6.
[0003]
The sprocket 1 and the platen roller 2 are provided on the main body 7. Reference numeral 8 denotes a cutter for cutting the printed sheet. The cutter 8 is provided on the main body 7. A drive gear mechanism for rotating the sprocket 1 and the platen roller 2 is provided in the main body 7.
[0004]
[Problems to be solved by the invention]
By the way, in such a printer, since the sprocket 1 is provided on the downstream side of the platen roller 2, the distance W between the thermal head 3 and the cutter 8 becomes long. For this reason, there has been a problem that the margin from the leading edge of the sheet to the position where characters are printed becomes long.
[0005]
Therefore, if the platen roller 2 is arranged on the downstream side of the sprocket 1, the margin can be shortened. In this case, however, the circumference of the platen roller 2 is prevented so that the sheet does not loosen between the platen roller 2 and the sprocket 1. It is necessary to feed the sheet at a slightly higher speed than the peripheral speed of the sprocket 1.
[0006]
However, at the start of printing, if the sprocket 1 rotates earlier than the platen roller 2 due to backlash, the sheet is loosened between the platen roller 2 and the sprocket 1, and the peripheral speed of the platen roller is high. As a result, the length of the first print character in the feed direction becomes long. This causes problems such as unstable printing distance accuracy.
[0007]
An object of the present invention is to provide a printer that can prevent the occurrence of sheet loosening due to backlash at the start of printing .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is a printer main body, a lid provided on the printer main body so as to be openable and closable, a sprocket that feeds a sheet from a sheet roll installed in the printer main body, and the sheet. A platen roller for printing on the sheet, a print head for printing on the sheet, a drive mechanism for rotating the sprocket and the platen roller, and a ribbon core on the winding side of the ink ribbon by the ink ribbon cassette mounted on the lid the a gear mechanism for rotating by the driving mechanism, said printer said sprocket body and provided with the platen roller, a printer provided with the print head on the lid,
The platen roller disposed downstream of the sprocket,
The take-up ribbon core gear engages with the gear on the one side of the gear mechanism when the lid is closed, and is applied between the gear on the supply side ribbon core connected via the ink ribbon. Backlash canceling means for eliminating backlash of the platen gear of the platen roller that meshes with the other side gear by slightly rotating the one side gear in the opposite direction against the force is characterized.
[0009]
In the invention of claim 2, a spring for always urging the lid and the printer main body in a direction of opening the lid is attached.
The ribbon core gear on the take-up side rotates the gear on one side of the gear mechanism slightly in the reverse direction by utilizing the force against the urging force of the spring when the lid is closed. It is characterized by eliminating platen gear backlash.
[0010]
The invention according to claim 3 is characterized in that the sheet is preliminarily fed by a predetermined amount before the sheet is preliminarily fed for printing.
[0012]
According to a fourth aspect of the present invention, there is provided feed-back means for feeding back the sheet by a total length of the preliminary feed amount, the idle feed amount, and the actually printed printing range.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a printer according to the present invention will be described below with reference to the drawings.
[0014]
The printer 10 shown in FIGS. 1 to 3 includes a printer main body 11 and a lid 50 attached to the printer main body 11 so as to be openable and closable.
[0015]
In the printer main body 11, a sprocket 12 for feeding sheets, a platen roller 13, a drive mechanism 20 for rotating the sprocket 12 and the platen roller 13, and a gear mechanism for rotating a ribbon core 63 of an ink ribbon cassette 60 described later. 30 and a cutter 18 for cutting the sheet are provided. The peripheral speed of the platen roller 13 is set to be slightly faster than the peripheral speed of the sprocket 12.
[0016]
The sprocket 12 is provided with a sprocket gear 14 as shown in FIG. 4, and a platen gear 15 and a torque limiter 19 are provided at one end of the platen roller 13 as shown in FIG. The torque limiter 19 causes the platen gear 15 to idle with respect to the platen roller 13 when a load exceeding a predetermined value is applied to the platen roller 13. A sheet roll 16 can be installed at the rear of the printer main body 11. Feeding holes (not shown) are provided at both ends of the sheet 16S of the sheet roll 16, and the projections 12a of the sprocket 12 are engaged with the feeding holes. Reference numeral 17 denotes a guide member that guides the printed sheet forward.
[0017]
The drive mechanism 20 includes a drive gear 21 provided on a drive shaft 53a of a stepping motor 53 (see FIG. 9), a gear 22 meshed with the drive gear 21, a gear 23 provided on the gear 22, and a gear 23. The gear 24 has a gear 24 and a gear 24 </ b> A provided on the gear 24. The gear 24 </ b> A meshes with the sprocket gear 14, and the gear 24 meshes with the platen gear 15.
[0018]
The gear mechanism 30 includes a gear 31 meshed with the platen gear 15, a gear 32 meshed with the gear 31, a gear 33 meshed with the gear 32, and a gear 34 provided on the gear 33. Have. The gear 34 meshes with a core gear 65 described later.
[0019]
A thermal head 51 is provided on the back side of the lid 50 and an ink ribbon cassette 60 can be detachably mounted. On the upper surface of the lid 50, there are provided various operation keys K for inputting characters and the like, and a display 52 for displaying the characters and the like input by these operation keys K. The rear part of the lid 50 is rotatably provided on a shaft 11J horizontally mounted on both side plates 11A of the printer main body 11, so that the lid 50 can be rotated and opened as shown in FIG. It has become.
[0020]
The side plates 11A of the printer main body 11 are provided with arc-shaped long holes 11H at positions above the shaft 11J, and pins 54 provided on the lid 50 are provided in the long holes 11H. Is movably inserted along. One end of a spring 55 is attached to the pin 54, and the other end of the spring 55 is attached to a locking portion 11 </ b> K provided in the printer main body 11. The lid body 50 is always urged in the direction to be opened by the spring 55, and this urging prevents the lid body 50 from being vigorously closed by its own weight when closing.
[0021]
As shown in FIGS. 7 and 8, the ink ribbon cassette 60 has ribbon cores 62 and 63 provided in the cassette 61, and core gears 64 and 65 attached to the ribbon cores 62 and 63. An ink ribbon 66 is wound around the ribbon core 62, and the ribbon core 63 winds up the ink ribbon 66.
[0022]
When the lid 50 is opened, the core gear 65 of the ink ribbon cassette 60 is disengaged from the engagement of the gear 34, and when the lid 50 is closed, the core gear 65 of the ink ribbon cassette 60 is engaged with the gear 34, as shown in FIG. The center position of the core gear 65 is positioned slightly below the center position of the gear 34. At this time, as shown in FIG. 10, the gear 34 is slightly rotated counterclockwise by the core gear 65. As a result of this rotation, the gears 32, 31, and 15 are rotated in the direction of the arrow shown in FIG. 9, and the backlash BR existing between the platen gear 15 and the gear 24 is illustrated as shown in FIG. 11 (B) is eliminated.
[0023]
FIG. 12 is a block diagram showing the configuration of the control system of the printer 10. In FIG. 12, reference numeral 71 denotes a control device that controls the thermal head 51, the display 52, the stepping motor 53, the cutter 18 and the like in accordance with the operation of each key K. This control device 71 comprises a CPU and the like, and functions as a preliminary feeding means for preliminarily feeding the sheet by L1 (first predetermined amount) in advance, and preliminarily feeds the preliminarily fed sheet by L2 (second predetermined amount). It has the function of the idle feeding means and the function of the return means for feeding back the sheet by the total length of the preliminary feeding amount, the idle feeding amount, and the actually printed printing range.
[0024]
Next, the operation of the printer of the above embodiment will be described.
[0025]
First, as shown in FIG. 6, the lid 50 is opened, the ink ribbon cassette 60 is attached to the lid 50, and the lid 50 is closed. Gear 34 by Koagia 65 closing the lid 50 is rotated slightly counterclockwise, backlash B R of the platen gear 15 is eliminated as shown in FIG. 11. At this time, the sheet roll 16 has already been set in the printer main body 11, and since the previous printing has been completed and the sheet 16S has been cut by the cutter 18, the leading edge of the sheet 16S as shown in FIG. The part 16a is assumed to be located at the position of the cutter 18.
[0026]
Next, a desired character or the like is input by operating the operation key K. Input characters and the like are displayed on the display 52. When printing is started by operating the operation key K, the control device 71 rotates the stepping motor 53. The platen roller 13 and the sprocket 12 are rotated through the drive mechanism 20 by the rotation of the stepping motor 53, and the sheet 16S is sent out from the sheet roll 16.
[0027]
At this time, since the backlash BR is eliminated, the sprocket 12 does not rotate earlier than the platen roller 13. For this reason, the backlash BR is caused between the platen roller 13 and the sprocket 12. Occurrence of looseness of the sheet 16S can be prevented.
[0028]
As for the sheet 16S, the preliminary feeding of the length L1 is first performed as shown in FIG. If the sheet 16S is loosened due to a factor other than the backlash BR between the platen roller 13 and the sprocket 12 by this preliminary feeding, the loosening is eliminated. This is because the peripheral speed of the platen roller 13 is set to be higher than the peripheral speed of the sprocket 12.
[0029]
Further, the meshing of the gears 22 to 24 and 14 can be made constant by the preliminary feeding. That is, backlash of these gears 22 to 24, 14 can be eliminated.
[0030]
Next, as shown in FIG. 13 (C), a length L2 idle feed is performed. These preliminary feed and idle feed are performed by counting pulses to the stepping motor 53. After this idle feeding, printing is performed on the sheet 16S by the thermal head 51.
[0031]
In this way, the sheet 16S is prevented from being loosened due to the backlash BR, and the pre-feed is performed before the idle feed, so that the slack of the sheet 16S can be reliably corrected, and the meshing of the gears is performed. Therefore, printing can be reliably performed at a predetermined position on the sheet 16S.
[0032]
As shown in FIG. 14A, when printing is completed, the driving of the stepping motor 53 is stopped, and thereafter, the stepping motor 53 is rotated in the reverse direction and the sheet 16S is fed back as shown in FIG. 14B. The length LR to be fed back is a length obtained by adding the length L4 of preliminary feeding performed after the second color, the length L2 of idle feeding, and the length L3 of sheet feeding at the time of printing. The number of pulses sent to the motor 53 is counted, and the returned length is obtained.
[0033]
When the sheet 16S is fed back by the length LR, the reverse rotation of the stepping motor 53 is stopped. Thereafter, the stepping motor 53 is driven to rotate forward, and the sheet 16S is preliminarily fed by a length L4 as shown in FIG. Then, as shown in FIG. 15 (A), the sheet is fed by the length L2, and then the second color printing is performed as shown in FIG. 15 (B) in the same manner as described above.
[0034]
Also during the printing of the second color, since the sheet 16S is loosened and the meshing of each gear becomes constant because the preliminary feeding is performed, the printing of the first color comes to the position of the thermal head 51. The sheet 16S can be sent out. Therefore, the second color can be reliably printed at the first color printing position, and color misregistration and the like can be reliably prevented.
[0035]
By the way, as shown in FIG. 14B, when the printing of the first color is finished, the sheet 16S is sent back by the length LR '(L1 + L2 + L3). At this time, the backlash Ba of the gears 22-24A It will actually return by LR = LR′−Ba minus (maximum backlash). However, even when the second color is printed, only the LR'-Ba subtracted by the backlash Ba of the gears 22 to 24A is actually sent out, so that it is not affected by the backlash Ba.
[0036]
When the printing of the second color is completed as shown in FIG. 15B, the sheet 16S is then fed back by the length LR as shown in FIG. 15C, and preliminary feeding and idle feeding are performed in the same manner as described above. To print the third color. This third color printing can be reliably printed at the position of the second color printing in the same manner as described above, and color misregistration or the like can be reliably prevented.
[0037]
According to this embodiment, since the platen roller 13 is disposed on the downstream side of the sprocket 12, the distance between the platen roller 13 and the cutter 18 can be shortened. The margin to the printing position can be shortened.
[0038]
In addition, according to this embodiment, since the torque limiter 19 is interposed between the platen roller 13 and the platen gear 15, when a load greater than a predetermined value is applied to the platen roller 13, the platen gear 15 is applied to the platen roller 13. Idle. For this reason, the sheet 16 </ b> S can be fed while giving a certain tension between the platen roller 13 and the sprocket 12.
[0039]
In the above embodiment, when the lid 50 is closed, the core gear 65 of the ink ribbon cassette 60 is engaged with the gear 34 to prevent the occurrence of the backlash BR. However, without the occurrence of the backlash BR, The slackness of the sheet 16S may be corrected only by the preliminary feeding before the idling.
[0040]
【The invention's effect】
According to the present invention, it is possible to prevent occurrence of sheet loosening due to backlash at the start of printing .
[Brief description of the drawings]
FIG. 1 is a perspective view showing an appearance of a printer according to the present invention.
FIG. 2 is an explanatory diagram showing an arrangement relationship of main parts of the printer.
FIG. 3 is an explanatory diagram showing an arrangement relationship of each gear of the printer.
FIG. 4 is a front view showing a sprocket.
FIG. 5 is a front view showing a platen roller.
FIG. 6 is an explanatory diagram of the printer showing a state when a lid is opened.
FIG. 7 is a side view showing an ink ribbon cassette.
8 is a plan view showing a state in which the lid of the ink ribbon cassette of FIG. 7 is removed. FIG.
FIG. 9 is an explanatory diagram showing the meshing relationship of each gear.
FIG. 10 is an explanatory view showing a gear meshing state.
FIG. 11A is an explanatory diagram showing backlash.
(B) It is explanatory drawing which eliminated the backlash.
FIG. 12 is a block diagram illustrating a configuration of a printer control system.
FIG. 13A is an explanatory diagram showing a positional relationship among a sheet, a cutter, and a thermal head.
(B) It is explanatory drawing which showed the state by which the sheet | seat was preliminarily fed.
(C) It is explanatory drawing which showed the state by which the sheet | seat was fed idle.
FIG. 14A is an explanatory diagram showing a state where printing of the first color has been completed.
(B) It is explanatory drawing which showed the state in which the sheet | seat was sent back only predetermined amount.
(C) It is explanatory drawing which showed the state in which the sheet | seat was preliminarily fed.
15A is an explanatory diagram showing a state in which the sheet is fed from the state shown in FIG. 14C. FIG.
(B) It is explanatory drawing which showed the state which the printing of the 2nd color was complete | finished.
(C) is an explanatory view showing a state in which the sheet is fed back by a predetermined amount.
FIG. 16 is an explanatory diagram showing a configuration of a conventional printer.
[Explanation of symbols]
11 Printer Main Body 12 Sprocket 13 Platen Roller 16 Sheet Roll 50 Lid 51 Thermal Head

Claims (4)

A printer main body, a lid provided on the printer main body so as to be openable and closable, a sprocket for feeding a sheet from a sheet roll installed in the printer main body, a platen roller for performing printing on the sheet, and printing on the sheet A print head that performs rotation, a drive mechanism that rotates the sprocket and the platen roller, and a gear mechanism that rotates the ribbon core on the winding side of the ink ribbon by the drive mechanism in the ink ribbon cassette mounted on the lid, sprocket the printer body and provided with the platen roller, a printer provided with the print head on the lid,
The platen roller disposed downstream of the sprocket,
The take-up ribbon core gear engages with the gear on the one side of the gear mechanism when the lid is closed, and is applied between the gear on the supply side ribbon core connected via the ink ribbon. A printer comprising backlash eliminating means for eliminating backlash of the platen gear of the platen roller that meshes with the other side gear by slightly rotating the one side gear against the force in the opposite direction. . A spring for always energizing the lid and the printer main body in the direction of opening the lid is attached,
The ribbon core gear on the take-up side rotates the gear on one side of the gear mechanism slightly in the reverse direction by utilizing the force against the urging force of the spring when the lid is closed. 2. The printer according to claim 1, wherein backlash of the platen gear is eliminated.   3. The printer according to claim 1, wherein the sheet is preliminarily fed by a predetermined amount before the sheet is preliminarily fed for printing. 4. The printer according to claim 3, further comprising a feed-back means for feeding back the sheet by a total length of the preliminary feed amount, the idle feed amount, and the print range actually printed .

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