KR100441540B1 - Paper feeding device for image forming device - Google Patents

Abstract

A paper feeding apparatus of an image forming apparatus is disclosed. The paper feeding apparatus of the disclosed image forming apparatus includes a paper feed cassette for accommodating paper, pickup means for transferring the paper into the image forming apparatus main body, and an image for separating and conveying the sheet sheet by sheet into the image forming apparatus main body. And a plurality of branch guides installed in the paper feed cassette so as to contact the leading end of the paper to be transferred to the forming apparatus main body, and a branching guide facing the leading edge of the paper among the branch guides. According to this, it is possible to prevent the midfeed phenomenon in which a plurality of sheets are conveyed when the sheet is conveyed toward the main body of the image forming apparatus and the folding of the corners of the sheet.

Description

Paper feeding device for image forming device

The present invention relates to an image forming apparatus, and more particularly, to a paper feeding apparatus for supplying paper to be printed to the image forming apparatus main body.

Typically, an image forming apparatus includes a main body of an image forming apparatus and a sheet feeding apparatus for supplying paper to be printed on the main body of the image forming apparatus. The image forming apparatus includes a driving unit for printing an image on the supplied paper, and a control unit controlling the driving unit. The paper feeding device includes a stacking means for stacking the paper, and a pickup means for picking up the loaded paper and transferring it to the driving unit. Typically, a paper feed tray provided on one side of the image forming apparatus main body and / or a paper cassette detachably mounted to the image forming apparatus main body is used as the paper loading means.

1 and 2 illustrate a side loading type paper feeding device 100. Referring to this, the paper feeding device 100 includes a pickup roller 120 as a paper pickup means, and the pickup roller. 120 is installed to be biased toward one of the corners of the leading edge of the paper (P) waiting for pickup transfer. When driving the pickup roller 120, the paper P is conveyed in the direction indicated by the arrow in FIG.

The recent paper feeding apparatus 100 further includes a plurality of branching guides 131 as branching means 130 for conveying the sheet of paper P by sheet to the main body of the image forming apparatus.

The branch guide 131 may feed the feed cassette 110 so as to sequentially contact the front end surface P1 and the lower surface P2 of the paper P when the paper P is transferred to the image forming apparatus main body (not shown). A plurality of papers are installed in the inside of each other, and a plurality of papers P are simultaneously transported to the image forming apparatus main body by using the contact friction force generated at the contact surface with the papers P to prevent the occurrence of so-called heavy feeding.

To this end, the branch guide 131 is formed of a material having a predetermined roughness, and is not shown in FIG. 2 so that the paper P is not disturbed from being transferred to the image forming apparatus main body by the contact friction force. Likewise, it is installed inclined with respect to the bottom surface 115 of the paper feed cassette 110.

As shown in FIG. 3, the paper P accommodated in the paper feeding cassette 110 has its front end rotated in the pick-up roller 120 at the beginning of driving the side-loading paper feeding device 100 as described above. It is bent along the direction and tries to be transferred. In this case, the shape of the curved surface formed on the portion of the front end of the paper (P) adjacent to the pickup roller 120 and the portion located away from the pickup roller 120 is formed differently. That is, the size of the curvature radius formed by the curved surface of the portion of the leading end of the paper (P) far from the pickup roller 120 is formed to be larger than the size of the curvature radius of the curved surface formed in the adjacent portion of the pickup roller (120). This is because the magnitude of the rotational driving force of the pickup roller 120 acting on the paper P is inversely proportional to the distance from the pickup roller 120.

Typically, the paper P to be conveyed to the image forming apparatus main body has its front end face P1 in contact with the branch guide 131 at its initial stage, and its lower surface P2 will be branched as the paper P continues to be conveyed. In contact with the guide 131. By the way, when the paper P is conveyed while the shape is changed by the pickup roller 120 as described above, even if the same paper P, the front end surface P1 in accordance with the distance from the pickup roller 120 After being in contact with the branch guide 131, the time taken for the lower surface P2 to contact the branch guide 131 is different. That is, a part of the paper P adjacent to the pick-up roller 120 is changed in its contact surface within a relatively fast time, but a part of the paper P located at a distance from the pick-up roller 120, in particular, a corner ( H) part will be slow to change the contact surface. Accordingly, the paper P advances in the conveying direction while the front end surface P1 of the corner H positioned far from the pickup roller 120 is in continuous contact with the branch guide 131. In this case, the feed from the edge H of the paper P located far from the pick-up roller 120 by the contact friction force between the front end surface P1 of the corner H side of the paper P and the branch guide 131. This is disturbed. In this way, when the paper P continues to move in the conveying direction in the state where the conveyance is hindered, the so-called ear fold phenomenon that the corner H portion of the paper P is folded without winning the driving force of the pickup roller 120 is obtained. This may occur, especially when the image forming apparatus is driven in a high humidity environment.

In order to solve this problem, it is possible to exclude the installation of the branch guide 131 in contact with the corner (H), but in this case occurs between the lower surface (P2) and the branch guide 131 of the paper (P) Due to the markedly reduced contact friction force, there is a problem in that the feeding of paper occurs more frequently.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a paper feeder of an image forming apparatus which can prevent the paper from being folded at the same time as the edge of the paper is prevented from being folded at the time of pick-up transfer of the paper. There is this.

1 is a plan view showing a paper feeder of a conventional image forming apparatus;

2 is a cross-sectional view showing an example of use of a conventional paper feeder taking the A-A section line of FIG.

3 is a state diagram showing a state of paper to be picked up and transported by the pickup means of FIG. 1;

4 is a plan view showing a paper feeding device of the image forming apparatus according to the present invention;

FIG. 5 is a cross-sectional view showing an example of use of the paper feeding device according to the present invention, taken along the line B-B in FIG. 4; FIG.

Explanation of symbols on the main parts of the drawings

200: paper feeding device 110: paper feed cassette

120: pickup roller 230: branch means

131: branch guide 135: support

231: anti-fold guide P: paper

H: corner

The paper feeding apparatus of the image forming apparatus according to the present invention for achieving the above object includes a paper feed cassette for accommodating paper, a pickup means for transferring the paper into the main body of the image forming apparatus, and a sheet feeder for transferring the paper by the pickup means. And a branching means formed of a plurality of branching guides installed in the paper feed cassette so as to contact the leading end of the paper, and separating the paper sheet by sheet, wherein the branching means is in contact with the front end surface of the paper being conveyed to the main body of the image forming apparatus. And at least one anti-folding guide installed on an inner wall side of the paper feed cassette facing the leading edge of the paper being picked up and waiting to be retracted a predetermined distance from the branch guides.

And, according to a preferred embodiment of the present invention, the anti-fold guide is installed to face the leading edge of the paper located far from the pickup means.

As a result, the sheet feeding is prevented and the folds are also prevented.

In addition, the folding prevention guide is preferably formed so that the branch guides installed to face the leading edge of the sheet among the branch guides are retracted toward the paper cassette main body side than the other branch guides.

Here, the folding prevention guide, it is preferable that the size of the inclination angle formed with the bottom surface of the paper feed cassette is formed smaller than the size of the inclination angle formed by the branch guide and the bottom surface of the paper feed cassette.

The branching guide and the anti-folding guide may be formed of a material having a predetermined roughness on a surface of the sheet that comes into contact with the front end side of the sheet.

In addition, the retraction distance of the anti-fold guide is such that the leading edge of the paper does not come into contact with the anti-fold guide at the beginning of the pick-up and transfer of the paper, and the leading edge of the paper is downward of the paper while the pick-up transfer is in progress. When it is stretched to the lower surface of the corner is set to a distance that can be in contact with the anti-folding guide, the retraction distance is preferably 1mm substantially.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. On the other hand, the components of the conventional paper feeding apparatus as shown in Figs. 1 and 2, and the components and the same configuration and function are denoted by the same reference numerals, and detailed description thereof will be omitted.

4 and 5, the paper feeding device 200 of the image forming apparatus according to the embodiment of the present invention includes a paper feeding cassette 110 for accommodating paper P, and a paper accommodated in the paper feeding cassette 110. And a pickup roller 120 for transferring P to the image forming apparatus main body (not shown), and branching means 230 for feeding sheet P into the image forming apparatus main body. The branching means 230 includes a branch guide 131 installed in the paper feed cassette 110 and a folding prevention guide 231 for suppressing the corners of the paper P from being picked up and transported.

The paper feed cassette 110 is detachably mounted to the image forming apparatus main body, and the pickup roller 120 is supported by a pickup arm 125 rotatably mounted to the image forming apparatus main body. In addition, various types of pickup transport means may be employed in the paper feeding apparatus 200, and a detailed description thereof will be omitted.

The branch guide 131 is formed of a material having a predetermined roughness, and is in a direction parallel to the front end of the paper P, that is, the paper feed cassette, so as to be in contact with the front end of the paper P being transferred to the image forming apparatus main body. A plurality of the paper cassettes 110 are installed at predetermined intervals along the transverse direction of the paper cassette 110. Here, as shown in FIG. 5, the branch guide 131 is installed to be inclined with respect to the bottom surface 115 of the paper feed cassette 110 so that the paper P is contacted with the branch guide 131 by the frictional force. The transfer to the image forming apparatus is not hindered.

As such, various methods may be used to install the branch guide 131 inclined with respect to the bottom surface 115 of the paper feed cassette 110. The branch guide 131 according to the present embodiment may be integrated with the paper feed cassette 110. It is supported by a support 135 formed as. That is, the branch guide 131 may be installed to be inclined as it is seated on the inclined surface 137 of the support 135 formed to be inclined with respect to the bottom surface 115 of the paper feed cassette 110. The size of the inclination angle θ ₂ formed with the branch guide 131 and the bottom surface 115 of the paper cassette 110 used for the paper cassette 110 that can accommodate 150 sheets of A4 paper is 70 ° to 72 ° is suitable. The support 135 and the branch guide 131 may be configured in various forms in addition to the above.

The branching means 230 according to the present invention configured as described above is installed on the inner wall side of the paper feeding cassette 110 facing the leading edge of the paper P waiting for pick-up transfer, at least installed to retreat a predetermined distance from the branch guides 131. At least one anti-fold guide 231 is included. The retraction distance d is such that the folding prevention guide 231 does not come into contact with the front end surface P1 of the paper P at the beginning of the pick-up transfer of the paper P, and the paper ( When the leading edge of P) extends down the sheet, the lower surface of the edge is set to a distance that can be contacted with the anti-folding guide 231.

In the present exemplary embodiment, the anti-folding guide 231 may include at least one branch guide 131 facing the leading edge H of the paper P among the branch guides 131. It is formed by retreating a predetermined distance from the remaining branch guides 131 toward the inner wall side of the paper feeding cassette 110 facing the front end. In addition, the folding prevention guide 231 is seated on the inclined surface 237 of the separate support 235 formed integrally with the paper feeding cassette 110 in the same manner as the branch guide 131.

As shown, the pick-up roller 120 in the side-loading paper feeder 200 is installed in close proximity to either side of the front end edge of the paper (P) in Figure 3, the anti-fold guide ( 231 is formed by installing a branching guide facing the leading edge (H) located far from the pickup roller 120 is retracted.

The operation state of the paper feeding device 200 according to the present invention configured as described above will be described with reference to the drawings.

When the image forming apparatus main body is driven while the paper feed cassette 110 is mounted, the pickup arm 125 pivots until the pickup roller 120 contacts the upper surface of the paper P accommodated in the paper cassette 110. . Pick-up roller 120 in contact with the upper surface of the paper (P) is rotated for the pickup transport of the paper (P), the paper (P) is pick-up transfer in the direction of the arrow shown in FIG.

In the case of the pick-up transfer, the paper P has the front end surface P1 of the paper P in contact with the branch guide 131 at the beginning of the pick-up transfer, and is subsequently subjected to the rotational driving force of the pick-up roller 120. Proceeds in the direction of the arrow as the front end lower surface (P2) of the paper (P) is in contact with the branch guide (131).

As described above, as the front end of the paper P is brought into contact with the branch guide 131, the plurality of papers P are picked up and transported at once, and the so-called paper feeding process is caused by the paper P and the branch guides. It is prevented by the contact friction force generated at the contact surface of 131.

On the other hand, the leading edge (H) of the paper (P) located at a distance from the pickup roller 120, as the folding prevention guide 231 is installed behind the other branch guides (131), the paper (P) ) Is not affected by the contact friction force because there is no part in contact with the front end surface P1. Thereby, the so-called ear fold phenomenon in which the leading edge H of the paper P is folded by the contact friction force can be prevented.

In this state, if the paper P continues to be conveyed while the lower surface P2 of the paper P is in contact with the branch guide 131, the leading edge H of the paper P is changed to the paper ( The paper is conveyed downward by the load of the tip of P). And, as described above, since the contact friction force is not applied to only one side edge portion H, a heavy feeding phenomenon may occur in which a plurality of sheets P are simultaneously conveyed at the corners H.

However, as described above, when a heavy feeding phenomenon occurs in the corner H of the paper P which runs downward, the paper P is in a state where the portion of the paper is stretched as the load of the leading edge H increases. As a result, the bottom surface P2 of the corner H comes into contact with the anti-folding guide 231. The conveyance of the paper P is suppressed by the contact friction force generated by such a contact. That is, by installing the anti-fold guide 231, it is possible to suppress the feeding of the paper P and at the same time prevent the ear fold phenomenon. It is preferable that the distance d between the anti-fold guide 231 and the branch guide 131 to ensure such an effect is substantially 1 mm.

Meanwhile, referring to FIG. 5, the inclination angle θ ₁ formed with the folding prevention guide 231 and the bottom surface 115 of the paper feed cassette 110 is larger than the size of the inclination angle θ ₂ of the other branch guides 131. It is formed in a small size. This is to suppress the tip surface P1 of the corner H from coming into contact with the anti-folding guide 231 when the paper P is conveyed while the edge P of the paper P is stretched. That is, even if the edge (H) of the paper (P) is stretched downward by the load to contact the folding prevention guide 231 so that the contact is inclined so that the corner (H) of the paper (P) is folded again. It can be prevented. In the present embodiment, the inclination angle θ ₁ of the anti-fold guide 231 is formed to be approximately 3 ° smaller than the inclination angle θ ₂ of the branch guide 131, and accordingly, the folding of the anti-fold guide 231 is performed. The inclination angle θ ₁ of the prevention guide 231 has a size of approximately 67 ° to 69 °.

In the above description of the present invention has been described as an example of a side loading type paper feeder having a unit of the anti-fold guide installed to correspond to one edge of the paper, this is not necessarily limited to this, the pickup roller is the central portion of the paper cassette; It can also be applied to the center-loading paper feeder is installed in the, and the anti-fold guide can also be applied in various forms without limitation of the number of installation if it can be installed only facing the edge of the paper located at a distance from the pickup means Of course.

The paper feeder of the image forming apparatus according to the present invention configured as described above is provided with a folding prevention guide to prevent the paper conveyed into the main body of the image forming apparatus from being fed back, and at the same time, the edge of the paper located away from the pickup roller is folded. You can prevent it.

While the invention has been shown and described with respect to preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will appreciate that various changes and modifications can be made to the present invention without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes, modifications, and equivalents should be considered to be within the scope of the present invention.

Claims (7)

A paper feeder for accommodating paper; Pickup means for transferring the paper into an image forming apparatus main body; And A plurality of branch guides installed in the paper feed cassette so as to contact the leading edge of the paper when the paper is conveyed by the pick-up means, and separating the paper sheet by sheet; and retreating a predetermined distance toward the inner wall of the paper feed cassette from the plurality of branch guides. And a branching means consisting of at least one anti-folding guide installed to And at least some of the at least one anti-folding guide are provided to face the leading edge of the paper located away from the pickup means. delete The method of claim 1, wherein the folding prevention guide, And a branching guide provided to face the leading edge of the sheet among the branching guides so as to be retracted toward the paper cassette body than the other branching guides. The method of claim 1, wherein the folding prevention guide, And an inclination angle formed with the bottom surface of the paper feed cassette is smaller than a size of the inclination angle formed by the branch guide and the bottom surface of the paper feed cassette. The method of claim 1, And the branching guide and the folding prevention guide are formed of a material having a predetermined roughness on a surface of the sheet that is in contact with the leading end of the sheet. The retraction distance of the anti-folding guide according to claim 1, If the leading edge of the paper does not come into contact with the front end face of the paper and the anti-folding guide at the beginning of the pickup, and the leading edge of the paper hangs downward of the paper while the pickup is in progress, The paper feeder of the image forming apparatus, characterized in that the distance that can be in contact with the folding prevention guide. The method of claim 6, And said retracting distance is substantially 1 mm.