JPH02291324A - Automatic sheet feed mechanism - Google Patents

Abstract

PURPOSE:To prevent sheets from being fed in a superposed condition and being fed erroneously, by changing the pressing force of a pressing means for pressing a sheet against a feed roller, in association with a sheet guide. CONSTITUTION:A sheet 2 which is loaded on a lift plate 3, is pressed against a feed roller 1 by means of a spring 10 through the intermediary of the lift plate 3. If the size of a sheet is small, levers 8a, 8b do not make contact with cam parts 9a, 9b on a sheet guide so that a spring attaching surface 7 is located at a lowest position. If the size of a sheet is large, the cam parts 9a, 9b are associatingly opened in the direction of the arrow 5, and the levers 8a, 8b are rotated in the direction of the arrow 4 by the cam parts 9a, 9b on the sheet guide. Further, the spring attaching surface 7 ascends so as to decrease the length of the spring 10, thereby the sheet 2 is pressed against the feed roller 1 with a relatively large force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic paper feeding mechanism for terminal equipment, etc., and particularly to a pressing mechanism that presses paper against a paper feeding roller. [Prior Art] As shown in FIG. 3, a conventional suppression mechanism of this type includes a paper feed roller 3 for feeding the paper 2 one by one from a paper tray 1, a lift plate 4 for placing the paper, and a paper feed roller 3 for feeding the paper 2 one by one from the paper tray 1. Spring 5 for pressing the paper feed roller 3 with constant pressure
It was configured to have

[Problem to be solved by the invention]

Since the above-described conventional pressing mechanism simply presses the paper against the paper feed roller using a spring, the paper pressure against the paper feed roller changes depending on the paper size.

For example, when stacking A5 size paper or postcard size paper, which is relatively light in weight, the pressing force on the paper feed roller is higher than with larger paper such as A4 size paper, which has the disadvantage of increasing the number of double feeds. Ta. On the other hand, in the case of relatively heavy paper such as B4 size, there is a drawback that the pressing force against the paper feed roller is insufficient, resulting in a paper feeding error in which the paper is not conveyed from the paper tray.

[Means to solve the problem]

The pressing mechanism of the present invention includes a paper guide that is movable depending on the paper size, a spring that presses the paper against the paper feed roller, and a mechanism that changes the pressing force against the paper in conjunction with the paper guide. There is.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 are cross-sectional views showing one embodiment of the present invention. The paper 2 is placed on a lift plate 3 and is pressed against a paper feed roller by a spring 10 via the lift plate 3. Paper guides 9a and 9b move in conjunction with each other in the directions of arrows 5 and 6 by means of a rack and pinion (not shown).

In the case of small sheets, the levers 8a, 8b do not contact the cam portions 9ac, 9bc of the sheet guide, so that the spring mounting surface 7 is in the position shown in FIG.

As shown in FIG. 2, in the case of large paper, the paper guide widens in the direction of arrow 5, levers 8a and 8b are rotated in the direction of arrow 4 by cam portions 9ac and 9bc of the paper guide, and spring mounting surface 7 is rotated in the direction of arrow 4. As the spring 10 rises, the length of the spring 10 becomes shorter, and the paper 2 is pressed against the paper feed roller 1 with a relatively large force.

〔Effect of the invention〕

As described above, the present invention has the effect of preventing double feeding of sheets and paper feeding mistakes by changing the pressing force of the pressure means that presses the sheet against the sheet feeding roller in conjunction with the sheet guide.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are cross-sectional views showing one embodiment of the present invention;
FIG. 3 is a sectional view showing a conventional paper feeding mechanism. 1...Paper feed roller, 2...Paper, 3.
... Lift plate, 4 ... Lever rotation direction, 5 ... Paper guide movement direction, 6 ...
...Paper guide moving direction, 7...Spring mounting surface, 8...Lever 9...Paper guide, 10...Spring. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] An automatic paper feed mechanism that includes a paper feed roller that feeds paper from a paper tray, a pressure unit that presses the paper against the paper feed roller, and a paper guide that is movable according to the paper size of the paper loaded in the paper tray. An automatic paper feeding mechanism characterized in that the pressing force of the paper feeding roller against the paper by the pressure means is changed in conjunction with the movement of the paper guide.