JPH10279119A - Paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve feed-in accuracy of recording paper by providing a cam member which displaces a pressing roller which presses the recording paper against a second paper feed roller which inverts and conveys the recording paper to a paper conveyance path in the direction of non-pressing in synchronization with the operation of a first paper feed roller. SOLUTION: A first pressing roller 7 and a second pressing roller 13 which are arranged around a sub-paper feed roller 2 as a second paper feed roller are apart from the surroundings of the sub-paper feed roller 2 by a cam 18 at the step where recording paper is fed into a paper feed roller 21. The first pressing roller 7 is supported on a common support frame 8 and is in pressure- contact with a peripheral face of the sub-paper feed roller 2 by an energizing spring 11 usually. The second pressing roller 13 is supported on a second roller release lever 14 and is in pressure-contact with or apart from the peripheral face of the sub-paper feed roller 2 by an energizing spring 15 which acts on the lever 14 and the cam 18. The cam 18 is supported by a shaft 17 and repeats forward and reverse rotations so that each pressing roller 7, 13 is brought into pressure-contact with or apart from the peripheral face of the sub-paper feed roller 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a paper feeder used for a printer.

[0002]

2. Description of the Related Art Providing a stack section of recording paper below a recording / writing section is a good measure for reducing the space required for arranging the apparatus. Must be formed in a U-shape, a difference occurs in the feed amount when the paper is thick, and when the paper is overlapped such as a label or an envelope, the inner paper and the outer paper are different. Floating occurs due to the difference in the curvature of the paper, and in the case of strongly stiff paper, the back tension is applied. As a result, the precision of feeding the recording paper deteriorates, which has a considerable adverse effect on print quality.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem.
It is an object of the present invention to provide a new paper feeder capable of transporting a recording paper to a recording / writing unit with high accuracy along a paper transport path having a large curvature regardless of a paper type.

[0004]

That is, the present invention provides a paper feeder for solving the above-mentioned problems, comprising a flat paper transport path having a first paper feed roller for feeding recording paper to a recording / writing section. A second paper feed roller for inverting and transporting recording paper from the stack section to a flat paper transport path, a pressing roller for pressing the recording paper against the second paper transport roller, and a paper for the first paper transport roller A cam member for displacing the pressing roller in the non-pressing direction in synchronization with the feeding operation.

[0005]

With this configuration, the pressing roller is displaced in the non-pressing direction in synchronization with the paper feeding operation of the first paper feeding roller, and the back tension of the recording paper on the reversing paper transport path is reduced. Thus, the paper feed control by the first paper feed roller is improved.

[0006]

Embodiments of the present invention will be described below. The drawings all show one embodiment of the present invention.

[0007] In the printer body indicated by reference numeral 1 in the figure, a recording paper in a hopper 3 is directed to the sub-paper feed roller 2 under the sub-paper feed roller 2 as a second paper feed roller. A pick-up roller 5 for feeding is provided, and a flat paper guide 20 having a main 21 paper feed roller as a first paper feed roller is provided above the sub-paper feed roller 2. The recording paper conveyed reversely in a U-shape is sent directly below the ink jet recording head 24.

Reference numerals 7, 7 and 13 denote first and second pressing rollers disposed around the sub-paper feeding roller 2, and these pressing rollers 7, 13 are used to feed the main recording paper. At the stage where the sheet is fed to the roller 21, the cam 18 described later is operated so as to be separated from the peripheral surface of the sub-sheet feed roller 2.

The first of these pressing rollers 7 and 13 is
Are supported by a common support frame 8, and are disposed on the lower side in the paper transport direction of the hopper 3 via the paper edge detection sensor 6, and the support frame 8 is swingable. The cam 1 which is connected to the tip of the pivotally supported first roller release lever 9 via a pressing rod 10 having a D-shaped cross section, and acts on this lever 9
8, when operated by the pressing roller 6,
6 operates so as to be separated from the peripheral surface of the sub paper feed roller 2, but is normally urged by the urging spring 11 to press the pressing rollers 6, 6 against the peripheral surface of the sub paper feed roller 2. .

On the other hand, the second pressing roller 13 is supported by the second roller release lever 14, and is provided at the junction of the flat paper guide plate 20 and the manual feed guide plate 22 by the sub-paper feed roller 2. The recording paper is disposed near and normally pressed against the peripheral surface of the sub-paper feed roller 2 by a biasing spring 15 acting on the lever 14, but the recording paper is fed under the main paper feed roller 21. The roller release lever 1
The cams 18 acting on the rollers 16 at the four ends are separated from the surface of the sub-paper feed roller 2.

On the other hand, the cam 18 is supported by the shaft 17 of the sub-paper feed roller 2 and is driven by a paper feed motor (not shown) to repeat forward rotation and reversal. To be separated from the peripheral surface of the feed roller 2,
They are pressed.

In FIG. 1, reference numeral 4 denotes a pad for preventing multi-sheet feeding provided at the tip of the hopper 3, reference numeral 25 denotes a cue detection sensor provided immediately before the main paper feed roller 21, and reference numeral 27 denotes a series of discharges. 2 shows a pair of paper rollers.

In the paper feeder constructed as described above, when a signal for paper feed is input, the cam 18 driven by the paper feed motor rotates in the direction of the arrow in FIG. Release the push-up of the lever 9, and
The two pressing rollers 7 by the urging spring 11 acting on
7 is equally pressed against the peripheral surface of the sub-paper feed roller, and the pressing of the second roller release lever 14 is also released. Press on the peripheral surface.

Therefore, when the pickup roller 5 starts rotating counterclockwise in this state, the recording paper pulled out from the hopper 3 by the roller 5
After reaching the sub-paper feed roller 2 through the pad 4 for preventing multi-sheet feed and the paper edge detection sensor 6, the paper is reversely conveyed while being pressed by the pressing rollers 7, 7, and passes between the second pressing rollers 13. And fed out onto a flat paper guide plate 20.

When the recording paper is fed to the main paper feed roller 21 in this manner, a cue detection sensor 25 disposed immediately before the recording paper detects the recording paper and outputs a sub-paper feed based on the detection signal. At the same time as the driving force to the roller 2 is cut off, as shown in FIG. 2, the planetary mechanism (not shown) is reversed, and the first roller release lever 9 is rotated counterclockwise in FIG. Then, the two pressing rollers 7, 7 pivotally supported by the support frame 8 are separated from the peripheral surface of the sub-paper feed roller 2, and the second roller release lever 14 is moved clockwise in FIG. Rotate to
The pressing roller 13 on the lever 14 is separated from the peripheral surface of the sub paper feed roller 2. Further, the sub paper feed roller 2
The transmission of the driving force to the motor is released by means such as a planetary lever or a one-way clutch.

As a result, the sub paper feed roller 2 can freely roll, and the recording paper wound thereon can also be released from the first and second pressing rollers 7 and 13 so that the main paper is released. The paper feed roller 21 of the sub paper feed roller 2
The recording paper is fed to the recording head 24 while controlling the feed amount of the recording paper on the flat paper transport path 20 without being affected by the recording paper 24, and a clear character is printed on the surface regardless of the paper quality. , Draw a figure.

When printing on manual paper such as a postcard, the paper is fed between the sub-paper feed roller 2 and the second pressing roller 13. Accordingly, a detection sensor (not shown) that has detected the manual feed paper activates the sub paper feed roller 2 based on the detection signal and feeds it to the main paper feed roller 21.
3 is separated from the sub-paper feed roller 2 and printing is performed. In this embodiment, since there is no difference in the curvature of the paper between the manual feed path and the automatic paper feed path, the same pitch accuracy can be obtained.

[0018]

As described above, according to the present invention, the second paper feed roller is provided on the flat paper transport path extending to the recording / writing section, while the recording is performed between the stack section and this paper transport path. A second paper feed roller for inverting and feeding the paper is provided, and a pressing roller for pressing the recording paper against the second paper feed roller is not pressed in synchronization with the paper feeding operation of the first paper feed roller. After the recording paper is fed to the first paper feed roller, the recording paper is released from the first paper feed roller by releasing the constraint of the recording paper on the second paper feed roller. In addition, the influence of the tension of the recording paper or the load associated with the conveyance of the recording paper can be reduced, eliminating the difference in the feeding amount depending on the paper type, and further improving the accuracy of feeding the recording paper to the recording writing unit. be able to.

Further, the transmission of the driving force to the second paper feed roller is interrupted in synchronism with the operation of the first paper feed roller, so that the load accompanying the feeding of the recording paper is further reduced. The accuracy of feeding the recording paper to the paper feeder can be further improved, and by arranging one of the pressing rollers at the confluence with the manual feed path, it is also possible to simultaneously feed the paper manually, and Can eliminate the difference in the paper feed amount.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention, showing a state of sheet feeding.

FIG. 2 is a configuration diagram of the above-described device showing a printing state.

[Explanation of symbols]

 2 Sub paper feed roller 3 Hopper 7, 7, 13 Press roller 18 Cam 20 Flat paper transport path 21 Main paper transport roller 22 Manual feed path 24 Recording head

Claims (3)

[Claims] 1. A flat paper conveyance path having a first paper feed roller for feeding recording paper to a recording writing section, and a second paper conveyance section for inverting and conveying recording paper from the stack section to the paper conveyance path.
A paper feed roller, a pressing roller that presses the recording paper against the second paper feed roller, and a cam member that displaces the pressure roller in the non-pressing direction in synchronization with the paper feeding operation of the first paper feed roller. And a paper feeder. 2. A paper feeder according to claim 1, further comprising means for cutting off transmission of a driving force to said second paper feed roller in synchronization with a paper feed operation of said first paper feed roller. apparatus. 3. The paper feeding device according to claim 1, wherein one of the pressing rollers is disposed near a junction of the flat paper conveyance path and the manual paper path.