JPS62249845A - Sheet feeding mechanism - Google Patents

Abstract

PURPOSE:To assure an optimum feed rate of a sheet at all times in correspondence to variance of various outer diameter precisions of a drive motor or various kinds of sheets by continuously varying the amount of rotation of a sheet feeding drive motor per pulse of a step motor. CONSTITUTION:Rotation of a shaft 5 is transmitted to a square shaft 7, rotation of which is in turn transmitted to a sheet feeding drive roller 13 through a friction roller 8 and a truncated cone roller 10. A sheet 14 is held between the drive roller 13 and a pressure roller 15 to be fed in a predetermined direction. As the friction roller 8 is movable on the tapered surface of the truncated cone roller 10 by sliding movement of a bracket 9, the amount of rotation of the sheet feeding drive roller 13 is continuously variable, and the position of the friction roller 8 is variable in correspondence to difference in thickness of sheets so as to adjust the amount of rotation of the drive roller 13.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper feed mechanism of a printing device, and particularly relates to a paper feed mechanism that always maintains an appropriate paper feed amount even under different usage conditions such as roller outer diameter accuracy and paper type. This invention relates to a paper feeding mechanism that can ensure the following.

[Prior Art] Conventionally, this type of paper feeding mechanism uses a step motor, and the amount of rotation (rotation angle) per pulse of the paper feeding drive roller is fixed.

[Problems to be solved] In the conventional paper feed mechanism described above, the amount of rotation of the paper feed drive roller per pulse of the step motor is fixed, so it is difficult to determine the accuracy of the outer diameter of the paper feed drive roller or the difference in paper thickness. The disadvantage is that the amount of paper feed per pulse is different between the two methods, which causes misalignment of line breaks in printing.

Solution to Problems] The paper feeding mechanism of the present invention that solves the above-mentioned conventional problems is as follows:
A paper feed drive roller, a conical trapezoidal roller directly connected to the paper feed drive roller, a friction roller that can freely move on the slope of the conical trapezoid roller and is pressed against the conical trapezoid roller, and transmits rotation to the friction roller. A step motor is provided, and the amount of rotation of the paper feed drive roller per one pulse of the step motor can be freely changed.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings showing a preferred example.

FIG. 1 is a schematic diagram of a paper feeding mechanism according to an embodiment of the present invention, and FIG. 2 is a partial side sectional view thereof. In FIG. Motor pulley 3 is provided on motor pulley 2.
4 is a pulley to which the rotation of the pulse motor 1 is transmitted by the timing belt 3;
is a shaft connected to the pulley 4, 6 is a universal joint, 7 is a square shaft connected to the shaft 5 via the universal joint 6, 8 is a friction roller pivotally supported on the square shaft 7 so as to be movable left and right; 9 is a bracket for moving the friction roller 8 from side to side on the square shaft 7; 10 is a conical trapezoidal roller that performs friction transmission with the friction roller 8; and 11.12 is for pressing the friction roller 8 against the conical trapezoidal roller 10 with a constant pressure. A spring provided on the square shaft 7, 13 a paper feed drive roller provided coaxially with the shaft 10a of the trapezoidal conical roller 10, 14 a paper, and 15 a paper feed drive roller 13.
This is a pressure roller that is placed in pressure contact with the

Drive of the step motor 1 is transmitted to a shaft 5 via a motor pulley 2, a timing belt 3, and a pulley 4. The rotation of the shaft 5 is transmitted to the square shaft 7 via the universal joint 6, and the rotation of the square shaft 7 is transmitted to the square shaft 7.
It is transmitted to the paper feed drive roller 13 via the friction roller 8 and the conical trapezoidal roller 10, which can freely move on the top and are pressed against the conical trapezoidal roller IO by springs 11 and 12. The paper 14 is sandwiched between the paper feed drive roller 13 and the pressure roller 15, and is fed in a fixed direction as the paper feed drive roller 13 rotates.

Therefore, since the friction roller 8 can freely move on the slope of the trapezoidal conical roller lO by sliding the bracket 9, the amount of rotation of the paper feed drive roller 13 per pulse of the step motor l can be changed steplessly. It becomes possible. Therefore, according to the paper feeding mechanism of this embodiment, the friction roller 8 can be
By changing the position of the paper feed drive roller 13 and adjusting the amount of rotation of the paper feed drive roller 13, an appropriate paper feed amount can always be obtained.

[Effects of the Invention] As explained above, the present invention can steplessly change the amount of rotation of the paper feed drive roller per pulse of the step motor, thereby improving the accuracy of the outer diameter of the paper feed drive roller, the type of paper used, etc. This has the effect of always ensuring an appropriate paper feed amount even under different conditions and eliminating line feed errors.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a paper feeding mechanism according to an embodiment of the present invention, and FIG. 2 is a partial side sectional view of the paper feeding mechanism according to an embodiment of the invention. 1 Step motor 2: Motor pulley 3: Timing belt 4: Pulley 5: Shaft 6: Universal joint 7: Square shaft 8: Fi rubbing roller 9 Ni bracket 1O: Conical trapezoidal roller ll Ni spring 1
2 Spring 13: Paper feed drive roller

Claims (1)

[Claims] A paper feed drive roller, a conical trapezoidal roller directly connected to the paper feed drive roller, a friction roller that can freely move on the slope of the conical trapezoid roller and is pressed against the conical trapezoid roller, and a step of transmitting rotation to the friction roller. 1. A paper feed mechanism, comprising: a motor, wherein the amount of rotation of the paper feed drive roller per one pulse of the step motor can be freely changed.