JPH11322123A - Paper feeding guide device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding guide device capable of always guiding various kinds of transfer paper such as postcards and envelopes having various kinds of widths in best conditions to the surface of a drum, and thereby is suitable on a transfer surface on which not only timing delay of a transfer but also dust of toner are surely prevented. SOLUTION: In a paper feeding guide device constituted by extending a paper feeding guide plate 9 having elasticity so that the idle end side may be close to the surface of a photoreceptor drum on a guide receiving member 7 on an upstream side of a transfer area, many cuttings (b) from the idle end part over the guide receiving member 7 are formed at prescribed intervals in a revolving axis line direction of the photoreceptor drum on an extended plate part 8 A of the paper feeding guide plate 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed guide device for a transfer paper to a transfer area of an image forming apparatus such as an electrostatographic copier, a facsimile, a printer, and the like. More specifically, the present invention relates to a paper feed guide device in which a free end side of a guide receiving member on the upstream side of a transfer area is extended so as to approach a surface of a photosensitive drum.

[0002]

2. Description of the Related Art The above-described paper feed guide plate guides a transfer sheet to a toner transfer area of a transfer device while smoothly bringing the transfer sheet into close contact with the surface of a photosensitive drum. If the transfer paper is soft, the paper guide plate slightly bends because the overhanging paper part from the free end side of the paper feed guide plate tends to fall forward, but the transfer paper is thick and hard. In this case, since the paper is strong, the paper feed guide plate is largely bent, and as a result, the transfer paper is closely adhered to the drum surface at a substantially constant position, and is smoothly guided to the toner transfer area. Will be.

[0003]

However, when the transfer paper is thick, as shown in FIG. 5, the paper feed guide plate 11 is bent in the pass area of the transfer paper a, but passes through the transfer paper a. The portion outside the region hardly bends, and the near-side portions 11a, 11a on both sides in the width direction of the transfer sheet a are in a state of being locally inclined. Therefore, excessive pressure is applied to both sides in the width direction of the transfer sheet a. Thus, both sides a ′ and a ′ in the width direction of the transfer paper a are warped upward, which strengthens the stiffness of the transfer paper a, and the transfer paper a sticks into the surface of the drum with a tendency to stick. Therefore, the transfer of the transfer paper a may be shifted, and the transfer timing may be slightly delayed.

When both sides a ′ and a ′ of the transfer sheet a in the width direction are warped upward, the transfer sheet a becomes difficult to adhere to the drum surface, and a gap is formed between the warped sheet surface and the drum surface. In some cases, when the toner is transferred to the warped paper surface, the toner spreads in the gaps, causing a problem of so-called toner dust.

[0005] Such a problem is particularly prominent when the transfer paper a is thick and narrow, such as a postcard or an envelope. Therefore, as a remedy, as shown in FIG. A paper feed guide device has been proposed in which a notch c is formed in a portion of the plate 11 corresponding to both sides of the fixed postcard in the width direction, so that the above-described curling is hardly generated.

However, in this technique, the paper feed guide plate 11
Since the notch c is formed only on the free end side of the transfer paper a, it is lacking in certainty of eliminating the warping of the transfer paper a. Further, for postcards and envelopes of various widths,
There was a problem in that it could not cope with this.

[0007] The present invention has been made in view of such circumstances, and various ratio papers such as postcards and envelopes of various widths can be obtained by rational improvement techniques that further develop the above-mentioned improvement measures. It is an object of the present invention to provide a sheet feeding guide device which is extremely suitable for a transfer surface and can reliably prevent the warpage of the sheet.

[0008]

The technical means adopted by the present invention to achieve the above object are as follows. That is, in a paper feed guide device in which an elastic paper feed guide plate is extended to a guide receiving member on the upstream side of the transfer area so that its free end is close to the surface of the photosensitive drum,
It is characterized in that a number of cuts from the free end to the guide receiving member are formed at predetermined intervals in the direction of the rotation axis of the photosensitive drum in the extension plate portion of the paper feed guide plate.

[0009] According to the above-mentioned characteristic configuration, since the deep cut is formed from the free end of the extension plate portion to the guide receiving member, the guide plate portions between the cut portions are individually bent and deformed. That is, this means that the guide plate portion outside the pass area of the transfer paper is not accompanied by bending deformation, and this guide plate portion does not apply any pressure to both sides in the width direction of the transfer paper. This ensures that the transfer paper is prevented from warping on both sides in the width direction.

Therefore, in addition to preventing the transfer timing from being delayed, the adhesion of the transfer paper to the drum surface is enhanced, so that the so-called toner dust is reliably prevented. Since a large number of papers are formed at predetermined intervals in the rotation axis direction of the body drum, various transfer papers, such as postcards and envelopes of various widths, should always be guided to the drum surface in the best condition. Becomes possible.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows transfer / separation devices 1 and 2 of an image forming apparatus.
The chargers 5 and 6 are stretched in the inner space of the inner shield case 3 and the side plate portions 3A and 3A at both ends in the sheet feeding direction of the inner shield case 3 so as to regulate the transfer region and the separation region by corona discharge.
3B, the upper plate portions 3a and 3b are bent downstream in the sheet feeding direction.

On the other hand, in the side plate 4A on the upstream side in the sheet feeding direction of the outer shield case 4, the upper plate 7
Is bent to the downstream side in the sheet feeding direction so as to face the bent plate portion 1a of the inner shield case 1, and the bent plate portion is used as the guide receiving member 7, and the guide receiving member 7 has elasticity. For example, a paper feed guide plate 8 made of, for example, a polyester film is extended so that its free end side is close to the surface S of the photosensitive drum 9, and a paper feed guide device 10 for guiding transfer paper to the drum surface S is provided. Make up.

In the paper feed guide device 10 having the above configuration,
As shown in FIG. 2, the sheet guide 8 has a plate 8A extending from the guide receiving member 7 toward the drum surface S. b are formed at predetermined intervals in the direction of the rotation axis of the photosensitive drum 9.
A number of cuts b are formed at a pitch of mm, and the guide plate portions 8a between the cuts b and b are individually bent and deformed.

In this embodiment, the photosensitive drum 9
1 shows a so-called center-based paper feed guide device 10 in which the center in the width direction of the transfer paper a is aligned with the center in the direction of the rotation axis of the transfer paper a. It is also possible to carry out the present invention for a so-called one-end reference paper feed guide device to be matched.

According to the above configuration, as shown in FIG.
When the transfer paper a is guided by the paper feed guide plate 8,
Only the guide plate portion 8a in the pass area of the transfer paper a is bent and deformed, and the guide plate portion 8a in a portion outside the pass area of the transfer paper a is not accompanied by the warp deformation. 8, since the locally inclined portion 11a is not formed unlike the related art, the transfer paper a does not warp on both sides in the width direction.
Therefore, the transfer paper a can be smoothly brought into close contact with the drum surface S without delaying the transfer timing.

Moreover, since a large number of the cuts b are formed at predetermined intervals in the direction of the rotation axis of the photosensitive drum 9, various transfer papers such as postcards and envelopes of various widths can be used. This can always be guided to the drum surface S in the best condition.

In the above embodiment, the notch b is formed so that the top of the triangle cuts into the guide receiving member 7, and the guide plate portion 8a formed by the notch b is also formed as a triangle. As shown in FIG. 4A, the cut b is formed in an arc shape so that the edges of the guide plate portion 8a are smoothly connected, or the guide plate portion 8a is formed in a rectangular shape as shown in FIG. Thus, the cut b may be formed in a rectangular shape.

Further, as shown in FIG. 4C, a simple slit cut b may be formed to form the guide plate portion 8a so as to be continuous in a strip shape.
As shown in FIG. 4 (D), a notch b may be formed at the tip to make a V-cut or the like, or not shown,
The free end side of the strip-shaped guide plate portion 8a may be formed in a triangular shape (in addition, an arc shape, a rectangular shape, or the like).

Although it depends on the size of the paper to be fed,
The interval between the cuts b is within 30 mm, preferably 5 to 20
mm, and the depth of the cut b depends on the elasticity of the paper feed guide plate 8, but is within 30 mm, preferably 3 to 3 mm.
A range of 0 mm is good. It is also possible to partially change the interval between the cuts b, or to provide a part without the cut b partially.

[0020]

As described above, according to the paper feed guide device of the present invention, the transfer timing delay caused by the warpage of the transfer paper on both sides in the width direction is reliably prevented. In addition, since the adhesion of the transfer paper to the drum surface is increased, so-called toner dust is reliably prevented.Furthermore, for various types of transfer paper such as postcards and envelopes having various widths, It can always be guided to the drum surface in the best condition.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a sheet feeding guide device shown together with a transfer / separation device of an image forming apparatus.

FIG. 2 is a plan view of a sheet feed guide plate in which cuts are formed.

FIG. 3 is a perspective view showing a state of bending deformation of a guide plate portion in a pass area of a transfer sheet.

FIGS. 4A to 4D are explanatory views of the shape of a guide plate portion formed by cutting in another embodiment.

FIG. 5 is an explanatory view showing a state in which a transfer sheet is warped on both sides in the width direction by a conventional sheet feed guide plate.

FIG. 6 is a perspective view of a paper feed guide plate proposed as an improvement for preventing warpage.

[Explanation of symbols]

7: guide receiving member, 8: paper feed guide plate, 8A: extended plate portion, 9: photosensitive drum, S: drum surface, b: cut.

Claims (1)

[Claims] 1. A sheet feeding guide device comprising a sheet feeding guide plate having elasticity and extended to a guide receiving member on the upstream side of a transfer area so that its free end is close to the surface of a photosensitive drum. A plurality of cuts extending from the free end to the guide receiving member are formed at predetermined intervals in the direction of the rotation axis of the photosensitive drum in the extension plate portion of the paper feed guide plate. Paper feed guide device.