JP2962018B2 - Printer paper feed mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed mechanism for a printer.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional paper feed mechanism, and FIG. 10 is an explanatory view (cross-sectional view) of FIG. The conventional paper feed mechanism includes a platen 1 that rotates in a paper feed direction 16 while holding a printing paper 20 (hereinafter, referred to as paper), a feed roller 18 that presses the paper 20 against the platen 1, and a paper 2.
0, a paper guide 15 for guiding the paper 20 to the printing position, a carriage 3 mounted with the print head 2 in front of the platen 1 and moving left and right on a guide shaft 32, and a paper discharge guide 42 for guiding the paper 20 to the discharge roller 41. And a paper discharge stacker 43 for storing the paper 20 discharged from the paper discharge rollers 41. At this time, in the discharge rollers 41, the paper 20
The peripheral speed of the roller is set faster than that of the platen 1 so that the paper 20 is not pulled up.

In the paper feeding operation, first, the carriage 3 moves to the center position of the paper width, the paper 20 is conveyed in a state of being wound around the platen 1, the leading end of the paper 20 advances along the paper guide section 15, and printing is performed. Stop at the start position and print. Then, the centering operation of stopping the carriage 3 at the center position of the sheet width and feeding the sheet is performed until the leading end of the sheet 20 advances along the sheet ejection guide 42. When printing is completed, the paper 20 is discharged and stored in a discharge stacker 43 by a discharge roller 41.

[0004]

In such a conventional paper feed mechanism, the paper 20 is pulled by the paper discharge rollers 41 so that the paper 20 comes into close contact with the platen 1. Floating from platen 1. For this reason, there is a disadvantage that the paper feed pitch becomes inaccurate.
In addition, since the centering operation is always performed at the time of paper feeding of several lines after the start of printing, there is a disadvantage that the printing throughput is reduced. In the case of the impact printing method, paper 2
There is a disadvantage that printing noise increases due to the floating of 0.

An object of the present invention is to solve the problem that paper rises from the platen surface during printing.

[0006]

According to the present invention, there is provided a paper feeding mechanism for a printer, comprising: a platen which rotates while a printing paper is attached thereto; A carriage that reciprocates substantially parallel to the direction, a bail roller that is rotatable and displaceable so as to be able to contact and separate from the platen, and a roller unit that is provided with a bail roller and that is rotatable and displaceable on the platen shaft.
And a discharge stacker for placing the printing paper discharged after printing.When feeding the printing paper to the printing position, the bail roller guides the leading end of the printing paper to the lower side in the transport direction. Displacing to a position 1;
While being synchronized with the rotation of the platen, the bail roller
And a step of displacing the discharged printing paper from the discharge stacker with the bail roller and the roller unit in synchronization with the rotation of the platen. And a control unit for performing a turning operation.

[0007]

1 shows a paper feed mechanism according to a first embodiment of the present invention, and FIG. 2 shows a part of the paper feed mechanism. The paper feed mechanism of the present invention includes a platen 1 that rotates forward and backward while holding a paper 20, a feed roller 18 that presses the paper 20 against the platen 1, and a paper guide unit 15 that guides the paper 20 to a printing position.
A carriage 3 on which a print head 2 is mounted in front of the platen 1 and which moves left and right on a guide shaft 32; a bail roller 4 which presses the paper 20 against the platen 1 to rotate in a subordinate manner; It comprises a roller unit 5 rotatable in the paper feed direction, and a paper discharge stacker 43 for storing printed paper 20.

As shown in FIG. 2, the bail roller 4 is directly pressed by the leaf spring 6 and is in pressure contact with the platen 1. At least one of the bearing portions that engages with the platen shaft 10 at both ends of the roller unit 5 is pressed by a spring 9 against a disk 11 fixed on the platen shaft 10, and is synchronized with the rotation of the platen 1 by the friction load of both. And pins 7 and 8
Between forward and reverse rotation. Also, a specific portion 3 of the carriage 3
The roller unit 1 is moved to and engaged with the meshing portion 53 of the roller unit 5, so that the roller unit 5 can be made to stand by at the sheet feeding position even if the platen 1 rotates forward and backward. Further, a guide unit 21 provided on the carriage 3 or the print head 2
Supports the rail portion 51 of the roller unit 5. Therefore, even when the platen 1 rotates in the reverse paper feed direction 17 (hereinafter, referred to as reverse rotation) by feeding the paper in the reverse direction during printing, the bail roller 4 on the roller unit 5 transfers the paper 20 after printing to the platen 1. Can be held in the pressing position.

The operation of the paper feed mechanism of the present invention will be described. First, the carriage 3 is rotated to the left at the meshing position at a rotatable position 5.
Move to 2. Second, as shown in FIG.
Rotates in reverse, and the roller unit 5 rotates in reverse in synchronism with it, and comes into contact with the pin 8 and stops. Third, the carriage 3 moves to the right and the engagement portion 5 of the roller unit 5 is moved.
3 is engaged. Fourth, the paper 20 is stored in the paper guide 1 of the printer.
5, the platen 1 rotates in the paper feed direction 16 (hereinafter referred to as forward rotation), and is conveyed while being wound around the platen 1 by the feed roller 18. Fifth,
When the leading end of the paper 20 passes through the bail roller 4, the platen 1
To stop the normal rotation of. Sixth, the carriage 3 is moved from the meshing position to the rotatable position 52. Seventh, the platen 1 is rotated forward to convey the paper 20 to the printing start position. At this time, the paper 20 is fed without being lifted off the platen 1 while being sandwiched between the bail rollers 4 on the surface of the platen 1. Eighth, as shown in FIG. 3, printing and paper feeding are sequentially performed. The roller unit 5 rotates forward in synchronization with the platen 1 and stops contacting with the pin 7 at a time to stop the forward rotation. If the paper is fed in the reverse direction during printing, the carriage 3
Alternatively, the operation is performed after the guide section 21 on the print head 2 is moved to a position where the guide section 21 contacts the rail section 51 of the roller unit 5.
Ninth, paper feeding is performed after printing is completed, and the paper feeding is stopped when the rear end of the paper 20 has passed the bail roller 4. Tenth,
The slider 70 provided with the pin 7 is moved by the carriage 3 in the direction of the arrow 71 to release the contact between the roller unit 5 and the pin 7. Eleventh, as shown in FIG. 5, the roller unit 5 is synchronously rotated by rotating the platen 1 forward, and the discharged paper 20 is pushed into the discharge stacker 43 at the roller unit corner 50.

FIG. 6 shows a part of a paper feed mechanism according to a second embodiment of the present invention. The paper feed mechanism according to the present invention includes the roller unit 5
The configuration is the same as that of the first embodiment except for a lever 61 which is engaged with the lever shaft hole 54 and is pressed by a spring 62, and a bail roller which is held by the lever 61 and pressed against the platen 1 to rotate in a subordinate manner. The operation is the same.

FIG. 7 shows a paper feed mechanism according to a third embodiment of the present invention. The paper feed mechanism of the present invention is provided with a power source (not shown) of a printer paper feed drive system (not shown) for rotating the roller unit 5 forward and reverse on the platen shaft 10 in synchronization with the platen 1. It has a power source 13 and a drive system 14 separately,
The configuration is the same as that of the first embodiment except that the roller unit 5 and the carriage 3 do not engage with each other.

The operation of the paper feed mechanism of the present invention will be described. First, the carriage 3 moves to the rotatable position 52. Second, as shown in FIG. 4, when the platen 1 is rotated in the reverse direction and stopped, the roller unit 5 receives the power from the drive source 13 via the transmission system 14 and rotates in the reverse direction to pick up the leading end of the paper 20. Stop at Third, the paper 20 is inserted into the paper guide 15 of the printer, the platen 1 rotates forward, and is conveyed while being wound around the platen 1 by the feed roller 18. Fourth, the roller unit 5 is rotated forward while synchronizing with the platen 1 at the same time that the leading end of the paper 20 passes through the bail roller 4. Fifth, as shown in FIG. 3, the paper 20 is transported to a printing start position, and the roller unit 5 is stopped and held at that position. Sixth, printing and paper feeding are sequentially performed. Seventh, as shown in FIG. 5, after the printing is completed, the paper is fed. When the trailing end of the paper 20 has passed through the bail roller 4, the roller unit 5 is rotated forward, and the discharged paper 20 is moved to the corner of the roller unit. At 50, the sheet is pushed into the discharge stacker 43.

FIG. 8 shows a paper feed mechanism according to a fourth embodiment of the present invention. In order to rotate the roller unit 5 on the platen shaft 10 while synchronizing with the platen 1, the paper feed mechanism of the present invention includes an electromagnetic clutch 12 on at least one of the bearings engaging with the platen shaft 10 at both ends of the roller unit 5. It is the same as the first embodiment except that it is attached.

The operation of the paper feed mechanism of the present invention will be described. First, the carriage 3 is rotated to the left at the meshing position at a rotatable position 5.
Move to 2. Second, the roller unit 5 is fixed to the platen shaft 10 by operating the electromagnetic clutch 12. Third
In FIG. 4, the platen 1 rotates in the reverse direction, and the roller unit 5 rotates in the reverse direction in synchronism therewith, and stops at the position where the leading end of the paper 20 can be picked up. Fourth, the operation of the electromagnetic clutch 12 is released. Fifth, the carriage 3 moves to the right and engages with the meshing portion 53 of the roller unit 5. Sixth, paper 20
Is inserted into the paper guide portion 15 of the printer, the platen 1 rotates forward, and is conveyed while being wound around the platen 1 by the feed roller 18. Seventh, when the leading end of the paper 20 passes through the bail roller 4, the normal rotation of the platen 1 is stopped,
The electromagnetic clutch 12 is operated. Eighth, the carriage 3
Is moved from the meshing position to the rotatable position 52. Ninth
Then, the platen 1 is rotated forward to transport the paper 20 to the printing start position. At this time, the paper 20 is fed without being lifted off the platen 1 while being sandwiched between the bail rollers 4 on the surface of the platen 1. Tenth, as shown in FIG. 3, printing and paper feeding are sequentially performed. The roller unit 5 rotates forward in synchronization with the platen 1 and releases the operation of the electromagnetic clutch 12 at a position where the bail roller 4 presses the paper 20 after printing. First
1, the paper is fed after the printing is completed, and when the rear end of the paper 20 has passed the bail roller 4, the electromagnetic clutch 12 is operated,
The roller unit 5 is rotated in synchronization with the platen 1. Twelfth, as shown in FIG.
Is pushed into the discharge stacker 43 by the roller unit corner 50 that rotates forward.

[0015]

As described above, in the paper feed mechanism of the present invention, the bail roller 4 rotates forward from the position where the bail roller 4 picks up the leading end of the paper 20 in synchronization with the platen 1, and further moves the paper 20 over the print head 2. And the roller unit corner 50 pushes the printed paper 20 into the discharge stacker 43. Therefore, the paper 20 does not rise from the surface of the platen 1 and an accurate paper feed pitch is obtained. In addition, since the centering operation of the carriage 3 when guiding the leading end of the paper 20 to the paper discharge guide 42 is not required, the throughput is improved. In addition, there is an advantage that the paper discharge roller 41 is not required. Further, in the impact-type printer, there is an advantage that the printing noise is reduced because the paper 20 does not rise from the surface of the platen 1.

[Brief description of the drawings]

FIG. 1 is a perspective view of a paper feeding mechanism according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a part of the paper feeding mechanism according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram at the time of printing according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram at the time of sheet feeding according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram at the time of paper ejection according to the first embodiment of the present invention.

FIG. 6 is a perspective view of a part of a paper feeding mechanism according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a paper feed mechanism according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a paper feed mechanism according to a fourth embodiment of the present invention.

FIG. 9 is a perspective view of a conventional paper feed mechanism.

FIG. 10 is an explanatory view of a conventional paper feed mechanism.

[Description of Signs] 1 Platen 2 Print Head 3 Carriage 4 Bail Roller 5 Roller Unit 43 Discharge Stacker

Claims (1)

(57) [Claims] A platen rotating with a print sheet attached thereto, a carriage reciprocating substantially parallel to a longitudinal direction of the platen while printing at a printing position on the platen by a carried print head; A bail roller which is rotatable and displaceable so as to be able to contact and separate from the roller, a roller unit which is provided with the bail roller and is rotatable and displaceable on the platen shaft, and a discharge unit for placing the printing paper discharged after printing. A paper stacker, wherein, when feeding the printing paper to the printing position, the bail roller is displaced to a first position so as to guide the leading end of the printing paper to the lower side in the transport direction; A step of displacing the bail roller from the first position to the second position so as to abut on the platen via the printing paper while synchronizing with the rotation of the platen. A step of displacing the bail roller and the roller unit to a third position so as to send the discharged printing paper to the discharge stacker while synchronizing with the rotation of the platen. A paper feed mechanism for a printer, comprising: