JPS594540A - Sheet feeder - Google Patents

Abstract

PURPOSE:To reduce a feeding resistance, by contacting such a quality material part as being large in a friction factor and installed in a feed roller, with a sheet in time of feeding the sheet through this roller, while contacting another material part lesser in the friction factor with the sheet this time when no sheet is fed. CONSTITUTION:A feed roller 4 delivering a sheet 2 one by one is formed by the way of projecting both a rubber-make feed roller 41 and a plastic auxiliary roller 21 being somewhat smaller in diameter than the said roller 41 upward from a square hole 3' made up in a sheet loading block 3. And, the feed roller 41 is secured tight to a shaft 20 while the auxiliary roller 21 is rotatably attached to the shaft 20, regulating the thrust direction by means of a grip ring 22. With this, if a flat part (a) of the feed roller 41 comes beneath the sheet loading block 3, a peripheral surface part (b) of the feed roller 41 conveys the sheet 2 forward. At this time, the auxiliary roller 21 rotates in accord with rotation of the sheet 2, reducing a feed resistance. Likewise, in time of stopping the shaft 20, the auxiliary roller 21 comes into contact with the sheet 2, thus the feeding resistance is reduced.

Description

Detailed Description of the Invention The present invention is applicable to copying machines, printing machines, recording machines, and other sheets (copying paper, transfer paper, printing paper, recording paper, printing paper, and other sheet forms used for recording images). This relates to a sheet conveying device for a machine, etc. (hereinafter referred to as a copying machine, etc.) that is equipped with a conveying mechanism for sheets (including sheets), and in particular, it relates to a sheet conveying device that has a sheet conveying roller that can stably convey sheets. be.

Conventional 1 In this sheet conveyance device, for example, in order to reliably convey the sheets stacked on a sheet tray to the sheet separation conveyance roller, an auxiliary sheet is placed upstream of the sheet separation conveyance roller in the sheet conveyance direction. A sheet conveyance port 2 is provided for feeding out the sheet, and the sheet is fed by pressing the sheet from above, that is, from the top of the sheet to increase the conveying force of the sheet conveyance roller. Then, the rotation and stopping of the sheet conveyance roller is performed by a magnetic clutch, and after the sheet is sent to the sheet separation/conveyance roller, the driving of the sheet conveyance roller is stopped and the sheet is moved using a one-way clutch, etc. There are those in which the sheet conveyance roller is driven, and those in which the sheet conveyance roller is lowered υ from the sheet stacking surface so that it does not contact the sheets.

However, these methods still have the disadvantage that a load due to frictional force is applied during the following, or a frictional force is generated due to contact between the sheet and the sheet tray, which becomes a resistance to conveyance. Ta.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a novel sheet conveying device that is improved in view of these drawbacks.

Another object of the present invention is to provide a sheet conveyance device having a sheet conveyance roller that reduces conveyance resistance during sheet conveyance.

That is, the main structure of the present invention that can achieve the above object is a sheet conveying device having a sheet conveying roller that feeds and conveys M-cut sheets one by one, and a part of the outer periphery of the sheet conveying roller is made of a material with a small coefficient of friction. When the sheet is conveyed by the sheet conveyance roller, the portion other than the material portion with the small coefficient of friction is conveyed by contacting the sheet, and when the sheet is not conveyed, the portion made of material with the low coefficient of friction is conveyed. This sheet conveying device is characterized by bringing a small material portion into contact with the sheet.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a sheet conveying section of a copying machine to which the present invention is applied. In the figure, 1 is a photosensitive drum having a photosensitive member rotatable in the direction of the arrow in the figure, and the photosensitive member has a photoconductive layer. A latent image forming means, a developing means, a cleaning means for removing residual toner after transfer, etc. are not shown and are omitted.

First, the transport path of the sheet material will be described. Sheet materials 2, which are conveyed in synchronization with the image on the photosensitive drum 1, are stacked and placed between a sheet stacking table 6 and a guide plate 14, which are attached to the apparatus.

Since the sheet material from the top of the loaded sheet materials to the lowest sheet material is pressed against the conveyance roller 4 by the sheet presser 16, the rotation of the roller 4 is slow, and the forward rotation roller 5
Then, the sheet material is sent to the roller 7 by the reverse rotation roller 5 and the forward rotation roller 5. At this time, even if several of the stacked sheet materials 2 collide with the forward rotation roller 5 and the reverse rotation roller B, the upper stage side is blocked by the reverse rotation roller 6, and only the lowest sheet is conveyed. The sheet material 2 sent to the conveyance roller 7 is sent to the photosensitive drum 1, and the image is transferred from the photosensitive drum to the sheet material by the transfer charger 8. Further, the sheet is placed on the sheet conveying belt 9.

Here, the separation roller 6 constantly rotates, the conveyance roller 4 and the forward rotation roller 5 start rotating at the same time, each rotates once by a one-turn clutch, etc., and then stops rotating.After that, the sheet is conveyed by the conveyance roller 7. Ru.

At this time, the normal rotation roller 5 has a built-in one-way clutch, so that it can be driven by the movement of the sheet.

Next, the structure of the conveyance roller 4 will be explained in detail with reference to FIGS. 2 to 5.

FIG. 2 is a detailed view of the conveyance roller 4, in which a square hole 6' is formed on the tip side of the sheet loading table 6, and a rubber conveyance roller 41 and a plastic auxiliary roller 21 protrude upward from the square hole 3I. ing. The conveyance roller 41 is connected to the shaft 20
The auxiliary roller 21 is fixed to the shaft 20 (see Fig. 6).
The grip ring 22 is rotatably attached to the cylinder, and the thrust direction of the cylinder is regulated by a grip ring 22. A one-turn clutch 26 and a gear 24 for receiving rotation are attached to the shaft 20 at its tip.

FIG. 4 is a cross-sectional view of the conveyance roller portion shown in FIG. 3, and the conveyance roller 41 is fan-shaped and has a slightly larger diameter than the auxiliary roller 21.

Now, when this conveyance roller 41 is normally stopped, the flat part a opposite to that in FIG. 4 is located upward (exactly 180 degrees
0 rotation state) The sheet melts and does not contact, and the auxiliary roller 2
1 is in contact.

Due to the rotation of the shaft 20, the flat part a of the conveying roller 41 is moved below the sheet loading table 6, so that the part of the conveying roller 41 with a larger diameter than the auxiliary roller 21 protrudes, and the part b (a certain length on the circumferential surface) The auxiliary roller 21 rotates following the sheet because it is pulled back to its original position after one rotation. Therefore, even if the sheet is held down by the sheet presser 16, only a small conveyance force is required due to the small amount of t, kQ/, on the circumferential surface of the auxiliary roller 21 and due to the free following.

Next, another embodiment will be described with reference to FIG.

A square roller 4B made of rubber is fixed to 11+20. Further, a metal fitting 27 is fixed to the sheet T-loading platform B, a shaft 25 is fixed to the metal fitting 27, and a roller 2 is attached to the shaft 25.
6 is rotatably attached.

FIG. 6 shows a cross-sectional view of the roller 26.
also protrudes from the surface of the sheet 8 (mounting table 3), and is in such a positional relationship that its apex C' protrudes beyond the roller 26 when the square roller 42 rotates.

When the conveyance of the sheet is stopped, the square roller 411 is placed in the position shown in Fig. 6.
The curly sheet is in contact with the roller 26.

With the rotation of IIIIII20, the corner roller 430 apex C (4 locations) contacts the sheet material and conveys the sheet.
After rotation, it returns to the position shown in Figure 4. At this time, the sheet material 2 is still being transported, so the sheet is in contact with the plastic rollers 26, but due to the low friction of the rollers 26 and the following, the load on the sheet is small, and the resistance of sheet transport is reduced. It is not.

As explained above, according to the configuration of the present invention, when a sheet is conveyed, the sheet is conveyed reliably by the material part with a large friction coefficient, and when the sheet is not conveyed, the material part with a small friction coefficient is brought into contact with the sheet, and the sheet is conveyed. Since the resistance can be reduced, the sheet can be conveyed stably.

Therefore, it is possible to further reduce wear and the like caused by the conveyance of the conveyance roller, thereby extending the life of the conveyance roller, and also preventing skewing and the like.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the conveying section of a copying machine, FIG. 2 is a perspective view showing the sheet conveying device of the present invention, FIGS. 6 and 4 are sectional views of the sheet conveying device, and FIG. and FIG. 6 are cross-sectional views of other embodiments. In the figure, 4 is a conveyance roller, 41 is a rubber conveyance roller, 21 is a plastic auxiliary roller, 4m is a corner roller, and 26 is a plastic roller.

Claims (1)

[Claims] In a sheet conveyance device having a sheet conveyance roller that feeds and conveys stacked sheets one by one, a part of the outer periphery of the sheet conveyance roller is formed with an exposed portion made of a material having a small coefficient of friction, and the sheet conveyance roller When the sheet is being conveyed, parts other than the material part with the small coefficient of friction are brought into contact with the sheet, and when one sheet is not being conveyed, the material part with the small coefficient of friction is brought into contact with the sheet. Sheet conveyance device.