JPH1087095A - Paper feeding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the paper feeding mechanism provided with a carriage enhanced in stability of paper feeding. SOLUTION: This feeding mechanism is provided with a pick-up roller 1 feeding the printing medium 7, a variable cam 3 driven by the pick-up roller 1, a movable roller 4 driven by both the printing medium fed by the pick-up roller 1 and the variable cam 3, an intermediate driven part-a 5 and an intermediate driven part-b 6, to which drive is transmitted by the movable roller 4, and with a back-up roller 2, to which drive is transmitted by the intermediate driven part-a 5 and -b. The change in cam shape of the variable cam 3 causes the back-up roller 2 to be driven with respect to the pick-up roller 1, both contact resistance and pressure are applied by the uppermost sheet of the printing medium 7 in contact with the pick-up roller 1 and the back-up roller 2 by means of driven motion and contact resistance with respect to the printing medium 7, the printing medium 7 is thereby prevented from being double fed.

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 paper feeding device, and more particularly, to holding a print medium when feeding paper.

[0002]

2. Description of the Related Art Currently, a paper feeding mechanism of a paper feeding device used is one mechanism of a device for printing on paper.
This mechanism transports paper having different paper sizes, thicknesses, hardnesses, and smoothnesses to a transfer mechanism without performing double feeding, picking mistakes, skew, and the like.

Next, this conventional paper feeding mechanism will be described with reference to the drawings.

FIG. 3 is a side view showing an example of a conventional paper feeding mechanism.

In the conventional paper feeding mechanism, the print medium 16 stacked on the lifter 12 is pushed up by the lifter spring 13 so that the surface of the print medium 16 is picked up by the pick roller 1.
The pick-up roller 11 is brought into contact with a rotating portion having a high frictional resistance, and is sent to the friction plate 15 by driving the rotating portion of the pick roller 11. Here, the friction plate 15 constantly applies a constant pressure to the pick roller 11, applies a constant pressure and frictional resistance to the print medium 16, and sends the print medium 16 to the paper feed section and thereafter. However, the surface state of the friction plate 15 is
In the case of an unstable state due to scratches, foreign matter, paper dust, etc., a plurality of print media 16 are fed. Normally, the frictional resistance is large between the pick roller 11 and the print medium 16, and the print medium 16
The distance between the print media 16 and the friction plate 15 is smaller than the frictional resistance between the pick roller 11 and the print media 16 and the frictional resistance between the print media 16. However, when the surface state of the friction plate 15 is unstable due to scratches, foreign matter, paper dust, or the like, the pick roller 11 and the printing medium 16,
The relationship between the print media 16 and the frictional resistance between the print media 16 and the friction plate 15 is broken, and a plurality of print media 16 are sent.

[0006]

A first problem is that a plurality of print media are fed at one time and a jam occurs.

The reason is that the surface condition of the friction plate is
If the condition is unstable due to foreign matter, paper dust, etc.
This is because the relationship between the frictional resistance between the print medium and the print medium, and between the print medium and the friction plate is lost.

[0008] The second problem is that the paper band of the print medium is limited, and the range of the state of the print medium is limited. It is not possible.

The reason is that, when the leading end of the print medium is in a curled state, the print medium comes into contact with a guide portion through which the print medium passes, and the print medium cannot be fed.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper feeding mechanism having a paper feeding mechanism with improved paper feeding stability.

[0011] Therefore, (1) The paper feeding mechanism of the present invention is a paper feeding mechanism for feeding a printing medium of a specified size having different thickness, hardness and smoothness. Pick roller,
The print medium is intermittently fed by a backup roller that assists the pick roller by interlocking a cam and a gear. (2) The paper feeding mechanism of the present invention includes a roller for feeding the print medium, a pick roller for constantly feeding the print medium,
A mechanism having two rollers, a backup roller and a backup roller, for preventing the next print medium from being fed after the print medium has been fed for a certain length regardless of the drive of the print medium. , The range of the state of the print medium is widened, and the print medium can be fed even when the print medium is curled. (3) The paper feeding mechanism of the present invention applies pressure to the first sheet of the printing medium that is in contact with the pick roller by a backup roller driven by the pick roller that feeds the printing medium,
It is characterized by preventing double feeding of print media by the contact resistance. Paper mechanism. (4) The paper feeding mechanism of the present invention includes a pick roller for feeding a print medium, a variable cam driven by the pick roller,
A movable roller driven by a variable cam to drive a print medium fed by a pick roller, a first intermediate driven portion and a second intermediate driven portion to which drive is transmitted by the movable roller; and a first intermediate driven portion. It is characterized by having a backup roller driven and transmitted by the driven portion and the second intermediate driven portion.

[0012]

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

FIG. 1 is a side view showing a case where the variable cam of one embodiment of the paper feeding mechanism of the present invention functions to prevent double feed, and FIG. 2 is an embodiment of the paper feeding mechanism of the present invention. FIG. 8 is a side view showing a case where the variable cam according to the embodiment has a function of preventing a pick error.

1 and 2, a paper feed mechanism according to the present embodiment includes a pick roller 1 for feeding a print medium 7;
A variable cam 3 driven by the pick roller 1, a movable roller 4 driven by the variable cam 3 for a print medium 7 fed by the pick roller 1, and an intermediate driven power transmitted by the movable roller 4. It comprises a section a5 and an intermediate driven section b6, and a backup roller 2 driven and transmitted by the intermediate driven section a5 and the intermediate driven section b6.

Next, the operation of the paper feeding mechanism of the present embodiment will be described with reference to FIGS.

In FIG. 1, when the variable roller 4 is in contact with the outer ring B of the variable cam 3 by the spring 8, the variable roller 4 is drawn to the outer ring B of the variable cam 3 by the spring 8 and is driven intermediately. There is no drive to section a5, and backup row
La 2 is no longer linked with pick roller 1. As a result, when the backup roller 2 is driven by the length of the print medium 7 and thereafter is driven by the movement of the print medium 7, the dead weight and contact resistance of the print medium 7 and the backup roller 2 are reduced. When the printing medium 7 is generated, the next printing medium 7 is held so as not to move, and feeding of a plurality of printing media 7 is prevented.

In FIG. 2, in a state where the print medium 7 is set in a mechanism for storing the print medium such as a hopper,
When performing the sheet feeding operation, the pick roller 1 feeds the print medium 7. When the variable roller 4 is in contact with the outer ring A of the variable cam 3, the intermediate driven part a5 and the intermediate driven part b6 are connected, and the backup roller 2 is driven at the same time as the pick roller 1, The print medium 7 is transported for a certain length. Thus, the pick roller 1 is changed depending on the length of the variable cams 3 A and B.
And the backup roller 2 can be driven at the same time, so that only the sheet having a shorter sheet length is driven simultaneously.

[0018]

The first effect is that the print medium is fed by the follower of the backup roller to the pick roller, the follower to the print medium, and the contact resistance due to the change in the cam shape, thereby preventing double feed. It is to become.

The reason is that the drive of the print medium fed by the pick roller is transmitted by the intermediate follower a by the variable cam.

The second effect is that the condition of the print medium is not restricted, the range of the print medium can be widened, and the print medium can be fed even if the print medium has a curled leading edge.

The reason for this is that the pick roller for feeding the print medium is the same as the roller that always feeds the print medium, and after the feed for a certain length, the next print medium is fed regardless of the drive. This is because a mechanism having two paper feed rollers and a backup roller for preventing the paper feeding is provided.

[Brief description of the drawings]

FIG. 1 is a side view showing a case where a variable cam according to an embodiment of a paper feeding mechanism of the present invention functions to prevent double feed.

FIG. 2 is a side view showing a case where the variable cam of the embodiment of the paper feeding mechanism of the present invention functions to prevent a pick error.

FIG. 3 is a side view showing an example of a conventional paper feeding mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pick roller 2 Backup roller 3 Variable cam 4 Variable roller 5 Intermediate driven part a 6 Intermediate driven part b 7 Print medium 8 Spring 11 Pick roller 12 Lifter 13 Lifter spring 14 Tension spring 15 Friction plate 16 Print media

Claims (4)

[Claims] 1. A paper feeding mechanism for feeding printing media of a specified size having different thickness, hardness and smoothness, a pick roller for feeding the printing medium, and a cam for connecting the pick roller to a cam. A paper feed mechanism wherein the print medium is intermittently fed by a backup roller assisted by gear interlocking. 2. A roller for feeding a print medium, a pick roller for constantly feeding the print medium, and a next length after feeding the print medium for a predetermined length, regardless of the drive of the print medium. By providing a mechanism having two rollers, a backup roller and a backup roller for preventing the printing medium from being fed, the state of the printing medium is not limited, the range of the state of the printing medium is expanded, and the A sheet feeding mechanism capable of feeding even a print medium having a curled leading end. 3. A pressure roller applies a pressure to the first sheet of the printing medium which is in contact with the pick roller by a backup roller driven by a pick roller for feeding the printing medium. A paper feed mechanism characterized in that the paper feed mechanism is prevented. 4. A pick roller for feeding a print medium, a variable cam driven by the pick roller, and the pick roller.
A movable roller driven by the variable cam to drive the print medium fed by the roller, a first intermediate driven portion and a second intermediate driven portion to which the drive is transmitted by the movable roller; and a first intermediate driven portion. And a backup roller driven by and transmitted by the second intermediate follower.