JPH05169741A - Paper feed mechanism for printer - Google Patents

Abstract

PURPOSE:To prevent the floation of a paper sheet from a platen by rotating a bail roller position synchronously with the platen. CONSTITUTION:A paper feed mechanism has the first position where a bail roller 4 can pick up the head of a paper sheet 20 when the sheet 20 is fed to a printing position, the second position where a bail roller 4 position rotates from the first position in the paper feed direction synchronously with a platen so that the bail roller 4 presses the paper sheet on the platen over a printing head at the time of printing, and the third position where the bail roller 4 and a roller unit 5 rotate from the second position synchronously with the platen to push the sheet into a paper discharge stacker 43.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A conventional paper feeding mechanism is shown in FIG. 9, and an explanatory view (cross-sectional view) of FIG. 9 is shown in FIG. The conventional paper feed mechanism includes a platen 1 that rotates in a paper feed direction 16 while holding a print paper 20 (hereinafter referred to as paper), a feed roller 18 that presses the paper 20 against the platen 1, and a paper 2
A paper guide portion 15 for guiding 0 to the print position, a carriage 3 for mounting 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 a discharge roller 41. , A paper discharge stacker 43 that stores the paper 20 discharged from the paper discharge rollers 41. At this time, the paper 20 is placed on the platen 1 in the discharge roller 41.
The roller peripheral speed is set higher than that of the platen 1 so that the paper 20 is not lifted from the platen 1.

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

[0004]

In such a conventional paper feeding mechanism, the paper 20 is pulled by the paper discharge roller 41 and comes into close contact with the platen 1. Lifted from Platen 1. Therefore, there is a drawback that the paper feed pitch becomes inaccurate.
In addition, since the centering operation is always performed when the paper is fed several lines after the start of printing, there is a drawback that the printing throughput is reduced. If the impact printing method is used, paper 2
There is a drawback that printing noise increases due to the floating of 0.

The present invention is intended to solve the problem that the paper floats from the platen surface during printing.

[0006]

According to the present invention, the first position where the bail roller 4 can pick up the leading edge of the paper 20 at the time of feeding to the printing position, and the position of the bail roller 4 from the first position are synchronized with the platen 1. The second position, which rotates in the paper feed direction 16 and the bail roller 4 presses the paper 20 against the platen 1 above the print head 2 during printing, and the bail roller 4 and the roller unit 5 synchronize with the platen 1 from the second position. A third position which rotates in the paper feed direction 16 and pushes the discharged paper 20 into the paper discharge stacker 43.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper feeding mechanism of a first embodiment of the present invention is shown in FIG. 1, and a part of the paper feeding mechanism is shown in FIG. The paper feeding mechanism of the present invention includes a platen 1 that rotates in the forward and reverse directions while holding the 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 that carries the print head 2 in front of the platen 1 and moves left and right on the guide shaft 32; a bail roller 4 that presses the paper 20 against the platen 1 and rotates in a subordinate manner; It is composed of a roller unit 5 rotatable in the paper feed direction and a paper discharge stacker 43 for storing the printed paper 20.

As shown in FIG. 2, the bail roller 4 is directly pressed by the plate spring 6 and is in pressure contact with the platen 1. At least one of the bearing portions that engage with the platen shaft 10 at both ends of the roller unit 5 is pressed by the spring 9 against the disk 11 fixed on the platen shaft 10, and is synchronized with the rotation of the platen 1 due to the frictional load of both. And then a pin 7, 8
Forward and reverse rotation between. In addition, the specific portion 3 of the carriage 3
By moving 1 and engaging with the meshing portion 53 of the roller unit 5, the roller unit 5 can be made to stand by at the paper feeding position even if the platen 1 rotates forward and backward. In addition, a guide portion 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 is rotated in the reverse direction 17 in the reverse direction during printing (hereinafter referred to as reverse rotation), the bail roller 4 on the roller unit 5 transfers the printed paper 20 to the platen 1. Can be held in the pressing position.

The operation of the paper feeding mechanism of the present invention will be described. First, the carriage 3 has a rotatable position 5 to the left of the meshing position.
Move to 2. Second, as shown in FIG. 4, the platen 1
Reversely rotates, and in synchronism therewith, the roller unit 5 reversely rotates and comes into contact with the pin 8 to stop. Thirdly, the carriage 3 moves to the right to move to the meshing portion 5 of the roller unit 5.
Engage 3. Fourth, the paper 20 is the paper guide 1 of the printer.
5, the platen 1 is rotated in the paper feed direction 16 (hereinafter, referred to as forward rotation), and is fed while being wound around the platen 1 by the feed roller 18. Fifth,
When the leading edge of the paper 20 passes the bail roller 4, the platen 1
Stop the forward rotation of. Sixth, the carriage 3 is moved from the mesh position to the rotatable position 52. Seventh, the platen 1 is normally rotated to convey the paper 20 to the print start position. At this time, the paper 20 is pinched by the bail roller 4 on the surface of the platen 1 and is not lifted from the platen 1 and is fed. Eighth, as shown in FIG. 3, printing and paper feeding are sequentially performed. The roller unit 5 rotates normally in synchronization with the platen 1 and comes into contact with the pin 7 to stop the normal rotation. If the reverse paper feed is performed during printing, the carriage 3
Alternatively, it is performed after the guide portion 21 on the print head 2 is moved to a position where it comes into contact with the rail portion 51 of the roller unit 5.
Ninth, the paper feed is performed after the printing is completed, and the paper feed is stopped when the trailing edge of the paper 20 passes the bail roller 4. Tenth,
The carriage 70 moves the slider 70 provided with the hit pin 7 in the direction of arrow 71 to release the contact between the roller unit 5 and the hit pin 7. Eleventh, as shown in FIG. 5, the platen 1 is normally rotated to synchronously rotate the roller unit 5, and the discharged paper 20 is pushed into the discharge stacker 43 at the roller unit corner portion 50.

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

FIG. 7 shows a paper feeding mechanism according to the third embodiment of the present invention. In the paper feeding mechanism of the present invention, in order to rotate the roller unit 5 in the forward and reverse directions on the platen shaft 10 in synchronization with the platen 1, a power source (not shown) of a printer paper feeding drive system (not shown) is used. Separately has a power source 13 and a drive system 14,
Moreover, 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 feeding mechanism of the present invention will be described. First, the carriage 3 moves to the rotatable position 52. Secondly, as shown in FIG. 4, when the platen 1 is in the reverse rotation and stopped state, the roller unit 5 obtains the power from the drive source 13 via the transmission system 14 and rotates in the reverse direction, and the position where the leading edge of the paper 20 can be picked up. Stop at. Thirdly, the paper 20 is inserted into the paper guide portion 15 of the printer, the platen 1 rotates forward, and is fed while being wound around the platen 1 by the feed roller 18. Fourth, at the same time when the front end of the paper 20 passes through the bail roller 4, the roller unit 5 is rotated in the forward direction in synchronization with the platen 1. Fifth, as shown in FIG. 3, the paper 20 is conveyed to the print start position, and the roller unit 5 is stopped and held at that position. Sixth, printing and paper feeding are sequentially performed. Seventhly, as shown in FIG. 5, after the printing is completed, the paper is fed, and when the trailing edge of the paper 20 passes the bail roller 4, the roller unit 5 is rotated in the forward direction, and the discharged paper 20 is fed to the corners of the roller unit. At 50, push into the output stacker 43.

FIG. 8 shows a paper feeding mechanism according to the fourth embodiment of the present invention. In order to rotate the roller unit 5 on the platen shaft 10 in synchronism with the platen 1, the paper feeding mechanism of the present invention has the electromagnetic clutch 12 on at least one of the bearing portions engaged 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 feeding mechanism of the present invention will be described. First, the carriage 3 has a rotatable position 5 to the left of the meshing position.
Move to 2. Secondly, the electromagnetic clutch 12 is operated to fix the roller unit 5 to the platen shaft 10. Third
Further, in FIG. 4, the platen 1 rotates in the reverse direction, and in synchronization with this, the roller unit 5 rotates in the reverse direction and stops at a position where the leading edge of the paper 20 can be picked up. Fourthly, 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, the paper 20
Is inserted into the paper guide portion 15 of the printer, the platen 1 rotates in the normal direction, and is fed while being wound around the platen 1 by the feed roller 18. Seventh, when the leading edge of the paper 20 passes the bail roller 4, the platen 1 is stopped from rotating normally,
The electromagnetic clutch 12 is activated. Eighth, the carriage 3
Is moved from the mesh position to the rotatable position 52. 9th
Then, the platen 1 is normally rotated to convey the paper 20 to the print start position. At this time, the paper 20 is pinched by the bail roller 4 on the surface of the platen 1 and is not lifted from the platen 1 and is fed. 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 the position where the bail roller 4 presses the printed paper 20. First
1, the paper is fed after printing is completed, and when the trailing edge of the paper 20 passes the bail roller 4, the electromagnetic clutch 12 is activated,
The roller unit 5 is rotated in synchronization with the platen 1. Twelfth, as shown in FIG.
Is pushed into the paper output stacker 43 at the corner 50 of the roller unit that rotates in the forward direction.

[0015]

As described above, in the paper feeding mechanism of the present invention, the bail roller 4 rotates forward in synchronization with the platen 1 from the position where the tip of the paper 20 is picked up, and the paper 20 is placed above the print head 2 by the platen 1. The roller unit corner portion 50 pushes the printed paper 20 into the paper discharge stacker 43. For this reason, the paper 20 does not float from the surface of the platen 1, an accurate paper feed pitch can be obtained, and the centering operation of the carriage 3 when guiding the leading end of the paper 20 to the paper ejection guide 42 is unnecessary, so that the throughput is improved. In addition, there is an advantage that the paper discharge roller 41 is unnecessary. Further, in the impact type printer, since the paper 20 does not float above the surface of the platen 1, there is an advantage that printing noise is reduced.

[Brief description of 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 of sheet feeding according to the first embodiment of this invention.

FIG. 5 is an explanatory view of the first embodiment of the present invention during paper ejection.

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

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

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

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

FIG. 10 is an explanatory diagram of a conventional paper feeding mechanism.

[Explanation of symbols]

 1 Platen 2 Print Head 3 Carriage 4 Bail Roller 5 Roller Unit 43 Paper Ejection Stacker

Claims (1)

[Claims] 1. A platen which rotates in the paper feed direction while holding a print sheet, a carriage which mounts a print head in front of the platen and moves left and right, a bail roller for pressing the print sheet against the platen, and a bail roller thereof. A roller unit attached and rotatable on the platen shaft,
In a printer having a discharge stacker for storing printed printing paper, a first position at which the bail roller can pick up the leading end of the printing paper at the time of feeding to the printing position, and the bail roller position from the first position are synchronized with the platen. A second position, which rotates in the paper feed direction and the bail roller presses the printing paper against the platen above the print head during printing, and the bail roller and roller unit rotate from the second position in synchronization with the platen, and the sheet is ejected. And a third position for pushing the print paper into the paper output stacker.