JP2512275Y2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sheet feeding device, and more particularly to a transfer sheet guiding structure in an image forming apparatus.

(Prior Art) In an image forming apparatus such as a copying machine or a printer, an electrostatic latent image corresponding to an original image is formed by exposing a photoconductor,
After the electrostatic latent image is developed, it is electrostatically transferred onto a transfer paper fed from a paper feed stack.

Inside the image forming apparatus, there is provided a structure for guiding the transfer paper from the paper feed stack to the transfer position of the photoconductor, and an example thereof is the structure shown in FIG.

FIG. 3 shows a sheet feeding portion of a copying machine which is one of image forming apparatuses, and a sheet feeding path 2 is arranged near the photoconductor 1.

In the illustrated case, the paper feed path 2 has two paths, one from the paper feed tray 3 and one from the manual paper feed tray 4. Each of these paths is in the feeding direction of the transfer paper indicated by arrow α. It joins at the upstream position of the registration roller 5 located on the upstream side of the photosensitive member 1.

The paper feed path from the paper feed tray 4 is provided with the registration roller 5 while the transfer paper S fed from the paper feed tray 4 is reversed.
The transfer sheet S on the sheet feed tray 4 is fed by a pickup roller 6 which is a half-moon shaped transfer sheet feeding member, and is placed in the middle of the feeding path. It is sandwiched and conveyed by the conveying roller 7, and is guided by the guide member 8 which is a reversing guide portion located in front of the registration roller 5 in the direction in which the conveyance direction is reversed and guided to the registration roller 5.

The guide member 8 enables the registration of the image leading end position and the transfer paper leading end position performed by the registration roller 5 and the correction of the skew (skew) occurring on the transfer paper, so that the registration member 8 is stopped. It receives the transfer paper that has bulged toward the transfer paper transport path side of the guide member 8 when it abuts against the roller.

Such a swelling of the transfer paper causes the amount of slack to be the amount of movement during skew correction, and when the registration roller 5 is re-rotated, a restoring force utilizing the strength of the waist of the registration roller 5 is generated to generate the registration roller 5. It is used to improve the entry condition, in other words, to improve the entry.

As a structure of the guide member 8, there is a structure in which, as shown in FIG. 4, the protruding lengths of the ribs 8A forming the guide surface located on the transfer sheet conveying path side are set to be the same length in the width direction of the transfer sheet.

(Problems to be Solved by the Invention) In the structure of the guide member 8 described above, the transfer sheet S is reversed by the guide member 8 when the leading end of the conveyed transfer sheet S reaches the guide member 8. While being guided while being expanded toward the transfer paper transport path side of the guide member 8, the guide member 8 collides with the guide member 8 substantially at the same time over the entire width direction, and if the noise at the time of the collision is large, noise may occur. .

An object of the present invention is to provide a paper feeding device having a structure capable of preventing noise caused by a collision between a transfer paper and a guide member in a conveying and guiding process in view of the above-mentioned problems in the conventional paper feeding device.

(Means for Solving the Problem) In order to achieve this object, the present invention comprises a reversing guide portion for reversing a transfer sheet conveyed by an intermediate conveying roller and guiding it to a registration roller. Is
In a paper feeding device in which a guide surface is formed on the transfer paper transport path side by a plurality of ribs arranged in parallel in the width direction of the transfer paper, the ribs are different in projection amount to the transfer paper transport path side. Other ribs are arranged between the ribs having a large protrusion amount, and the difference in the protrusion amount between the rib having the larger protrusion amount and the other rib is transferred to the registration roller by the reversing guide portion. It is characterized in that the length of the transfer paper in the guided process is set so as to come into contact with at least one of the other ribs after coming into contact with the rib having the larger protrusion amount.

Further, the present invention is characterized in that the ribs are arranged substantially symmetrically with respect to the center of the inversion guide portion in the width direction.

(Operation) According to the present invention, only a part of the leading end of the transfer sheet conveyed by the intermediate conveying member abuts on the rib having the larger protrusion amount. After that, the transfer sheet guided to the registration roller by the guide member which is the reversing guide section swells toward the transfer sheet conveying path side of the guide member, and this swelled surface abuts the rib with the larger protrusion amount Abut the rib.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view for explaining a main part of the paper feeding device of the present invention. In FIG. 1, the same components as those shown in FIG. 3 are designated by the same reference numerals.

The feature of the present invention resides in that the protruding length of the guide rib formed in the reversing guide portion is changed in the width direction of the transfer paper.

The guide 10 used for the inversion guide portion is formed of, for example, a resin molded product, and a plurality of guide ribs 10A are arranged in parallel along the width direction of the transfer sheet S.

The plurality of guide ribs 10A are formed by a plurality of rib groups having different projecting amounts, that is, projecting lengths from the base portion to the tip forming the guide surface on the transfer sheet conveying path side that abuts the transfer sheet S. Since the other ribs are arranged between the ribs having a large amount, the protruding length differs in the width direction of the transfer paper, and a step is provided on the contact surface with the transfer paper in the width direction. . In the case of the present embodiment, as shown in FIG. 2, the transfer paper S is set in a wavy shape and has a length such that the transfer paper S can make contact with the transfer paper S in the same plane. The difference in the amount of protrusion between the rib with the larger amount of protrusion and the other ribs means that after the transfer sheet S is in contact with the rib with the greater amount of protrusion in the process of guiding the registration roller by the reversing guide portion, At least one of the ribs
It is set to a length that abuts on one.

The guide ribs 10A are arranged substantially symmetrically with respect to the widthwise center of the inversion guide portion.

Since the present embodiment has the above-described structure, the leading end of the transfer sheet S conveyed by the conveying roller 7 which is an intermediate conveying member comes into contact with the rib having the larger protrusion amount. After that, the transfer sheet S guided to the registration roller 5 while being reversed by the guide member 10 which is a guide used for the reversing guide section,
When the guide member 8 is stopped by being abutted against the registration roller 5, the guide member 8 bulges toward the transfer paper conveyance path side, and the bulged surface abuts on the rib having the larger protrusion amount and then on the other ribs.

(Effect of the Invention) As described above, according to the present invention, the protrusion amount of the guide rib used for the reversal guide portion in the transfer paper transport path toward the transfer paper transport path is different in the width direction of the transfer paper. While preventing skew, only the tip of the conveyed transfer paper and only a part of the surface of the transfer paper that has bulged toward the transfer paper conveyance path side of the reversal guide part are first made to collide with the rib with the larger protrusion amount. , Then it can collide with other ribs.
Therefore, as compared with the case where the entire width direction collides with each other at the same time, the collision noise can be suppressed by reducing the collision noise generation area, and the noise can be prevented from occurring.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a guide which is a reversing guide part of a sheet feeding device showing an embodiment of the present invention, and FIG.
FIG. 3 is a schematic cross-sectional view showing an example of a sheet feeding device, and FIG. 4 is a view taken in the direction indicated by line IV in FIG. DESCRIPTION OF SYMBOLS 1 ... Photosensitive member, 2 ... Paper feeding path, 3 ... Tray having paper feeding stack, 5 ... Registration roller, 6 ... Pickup roller, 7 ... Conveying roller which is an intermediate conveying member, 9 ...
... Paper feeder, 10 ... Guide that is a reverse guide member, 10A ...
… Rib for guide, S… Transfer paper.

Claims (2)

(57) [Scope of utility model registration request] 1. A paper feed stack for stacking transfer paper, an intermediate conveyance roller for conveying the transfer paper fed from the paper feed stack, and a resist for reversing the transfer paper conveyed by the intermediate conveyance roller. A reversing guide part for guiding the roller, wherein the reversing guide part is provided on the transfer paper transport path side,
In a paper feeding device in which a guide surface is formed by a plurality of ribs arranged side by side in the width direction of the transfer paper, the ribs include a plurality of rib groups having different projecting amounts toward the transfer paper transport path side, Between ribs with a large amount of protrusion,
The other ribs are arranged, and the difference in the protrusion amount between the rib having the larger protrusion amount and the rib having the larger protrusion amount is the difference in the protrusion amount of the transfer paper having a large protrusion amount such that the transfer paper is guided to the registration roller by the reversing guide portion. A sheet feeding device having a length set to abut on at least one of the other ribs after abutting on the rib. 2. The paper feeding device according to claim 1, wherein the ribs are arranged substantially symmetrically with respect to the center of the reversing guide in the width direction.