JPH058290Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper ejecting device in an image forming apparatus such as a copying machine or a printer.

[Conventional technology]

For example, as shown in FIG. 7, a copying machine's sheet ejecting device includes a plurality of sets of sheet ejecting rollers 25 and 26 that nip and convey the edges and intermediate portions of recording paper on both sides in the width direction.
A pair of upper and lower paper feed guides 27 and 28 are provided at a predetermined distance in the axial direction, and upper and lower paper feed guides 27 and 28 are provided to guide the recording paper after heat fixation to the pair of paper ejection rollers 25 and 26. 27 is arranged in a vertical rib shape between adjacent rollers 25, 25 (in the illustrated example, the lower paper feed guide 28 is also arranged in a vertical rib shape). There is.

In the above paper ejection device A, if the upper paper feed guide 27 is shaped like a face plate, it becomes difficult for water vapor from the recording paper a generated by heat fixing to dissipate, resulting in dew condensation on the paper feed guide 27. However, by forming the paper feed guide 27 in the form of vertical ribs, the water vapor can be effectively dissipated, and there is an advantage that dew condensation can be prevented.

[Problem that the invention attempts to solve]

By the way, the front edge of the corner of the recording paper a introduced into the paper discharge device A tends to curl upward due to the thermal influence of the thermal fixing device 13 in the previous stage, as shown in FIG. .

When the curled portion _a1 at the front end of the corner passes through the nip portions of the pair of left and right paper ejection rollers 25 and 26, which nip and convey the recording paper by nipping the edges on both sides in the width direction, The curled portion _a1 is sometimes held and conveyed by the paper discharge rollers 25 and 26 in a folded state, resulting in a drawback that so-called corner folds are likely to occur.

Alternatively, when recording paper a is fed from a cassette case that has claws on both sides of the front end to prevent double feeding, the front edge of the corner of the recording paper a may curl downward, and The curl may be increased due to the effect of fixing, and in such a case, the nipping and conveying action of the paper ejection rollers 25 and 26 may cause downward corner bending.

The present invention aims to eliminate the above-mentioned corner folds through simple improvements.

[Means for solving problems]

In order to achieve the above object, the present invention provides a plurality of pairs of upper and lower paper ejection rollers that nip and convey the edges and intermediate portions of recording paper on both sides in the width direction, and also In a paper ejecting device of an image forming apparatus, in which upper and lower paper feeding guides for guiding the recording paper toward the rollers are arranged so that at least the upper one forms a vertical rib between the rollers, the front edge of the corner of the recording paper is The present invention is characterized in that a guide member is provided to guide the paper to the nip portion of the pair of paper ejection rollers.

[Effect]

According to the characteristic structure described above, when the front edge of the corner of the recording paper is nipped by the pair of upper and lower paper ejection rollers, the front edge of the corner that has become slightly curled due to thermal effects is ejected. Before the paper is fed into the pair of paper rollers, the curled portion at the front end of the corner is moved along a guide member and flattened.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings. FIGS. 1 and 2 show a paper ejecting device A, and FIG. 5 schematically shows the entire copying machine. , a photoreceptor 4 is horizontally mounted on a copying machine main body 3 equipped with a document holder 2 on the upper part for contact glass 1, and a charging section 5,
A developing section 6, a transfer section 7, a recording paper separating section 8, and a cleaning section 9 are arranged in this order in the rotation direction R of the photoreceptor, and an exposure device 10 with a moving optical system is installed in the space below the contact glass 1. A paper feeding and conveying device 12 is provided for conveying the recording paper a in the cassette case 11 to the transfer section 7, and a recording paper a after separation is provided.
a discharge paper conveyance device 14 that conveys the paper to the heat fixing device 13;
Further, a paper ejecting device A is provided to eject the recording paper a after thermal fixation onto the tray 15.

The fixing device 13 includes a pair of upper and lower heating rollers 1.
6 and a pressure roller 17, one heating roller 16 has a heater 19 such as a heating lamp or a coil built inside a metal cylindrical roller body 18 whose surface is coated with fluorocarbon resin or the like. The other pressure roller 17 has a metal roller body 20 and a thick elastic cylinder 21 made of silicone rubber or the like.
are fitted externally, and both side plates 22, 22
It is constructed in

The paper ejecting device A is constructed as follows. That is, as shown in FIGS. 1 and 2, the side plates 22,
22, the upper rotating shaft 23 is vertically movable along the long holes b formed in the side plates 22, 22, and a narrow upper paper ejection roller 25 and a wider lower paper ejection roller 26 are installed. A plurality of pairs (four pairs are exemplified) are attached to the rotating shafts 23 and 24 at a predetermined interval in the axial direction, and the recording paper after being thermally fixed is attached to the pair of upper and lower paper ejection rollers 25 and 26. Upper and lower paper feeding guides 27..., 28 and a guide member 29 are arranged for guiding the paper.

Note that among the lower paper ejection rollers 26, the one on the center side has one flange, and the one on both sides has both flanges, and the recording paper a to be ejected is bent in the width direction and recorded. Paper a is made stiff so that it can be ejected.

As shown in FIGS. 1, 2, and 4, the upper paper feed guide 27 is made of a plate-shaped material punched into an H-shape by press processing, with the punching burr i formed by the press positioned above. In this state, both sides are folded downward so that the folding angle θ with respect to the mounting surface portion 27a becomes an acute angle, and the vertical rib-shaped portion formed by the folding is used as the paper feeding guide 27. The mounting surface portion 27a is connected to the connecting member 3 that spans the side plates 22, 22 so that the paper feeding guide 27 is located between the upper paper ejection rollers 25, 25.
It is fixed at 0.

According to this configuration, conventionally, the vertical rib-shaped sheet feeding guide 27 was arranged vertically and downwardly, so that the punching burr i had to be removed, but as described above, By making the folding angle acute, the burr i is located above the guide surface of the recording paper a, which has the advantage of eliminating the need for burr removal.

The other lower paper feed guide 28 is made of a face plate member with a portion corresponding to the lower paper ejection rollers 26 cut out, and a portion 28 that curves downward between the cut portions.
a is located between the lower paper ejection rollers 26, 26.

Now, the guide member 29 is provided on the introduction section side of the recording paper a in correspondence with the left and right pair of paper ejection rollers 25 and 26, and
When the pairs of paper ejecting rollers 25 and 26 nip the edges on both sides in the width direction of the recording paper a and convey it, the upper surface side of the front edge of the corner of the recording paper a is directed downward to the nip portion of the pair of paper ejection rollers 25 and 26. As shown in Figures 1 to 3, the L-shaped plate material is bent,
A mounting surface c for the continuous member 30, a hanging surface d bent downward from the surface c, a horizontal surface e bent horizontally from the lower end of the surface d, and a direction from the horizontal surface e toward the nip portion. The width L of the inclined guide surface portion f is the same as that of the paper ejection rollers 25 and 26.
The nip width between the pair is wider than the width l of the narrow upper paper ejection roller 25, and the front edge of the corner of the recording paper a nipped by the upper and lower paper ejection rollers 25 and 26 curls upward. Even if the paper is slightly curled, uncurl it and straighten it to make it flat.
It is designed to be supplied for 26 days.

Another embodiment of the guide member 29 is shown in FIG. This is made by bending an L-shaped plate material to form a mounting surface g for the continuous member 30, and a rib-shaped inclined guide portion h extending from this surface g toward the upper and lower paper discharge rollers 25 and 26. In addition, the inclined guide portion h is arranged within the nip width between the pair of paper ejection rollers 25 and 26, that is, within the width of the narrow upper paper ejection roller 25, and in this case also, the folded guide portion h with respect to the mounting surface portion g is By making the angle θ ₁ acute, removing burrs by press working can be made unnecessary.

Note that the front edge of the corner of the recording paper a may curl slightly as it moves downward; in such a case, the front edge of the corner of the recording paper Alternatively, the guide members 29 may be arranged in pairs, upper and lower, so as to guide both the top and bottom of the front edge of the corner of the recording paper a to the nip part. It's okay to do that.

[Effect of idea]

As explained above, in the paper ejecting device of the image forming apparatus according to the present invention, the front edge of the corner of the recording paper is introduced into the nip portion of the pair of paper ejection rollers that nip and convey the edges of the recording paper on both sides in the width direction. Before transporting the front edge of the corner of the recording paper along the guide member, the front edge of the corner that has become slightly curled is flattened, and the front edge of the corner of the recording paper is ejected. The paper is supplied to the nip portion of the roller pair, thereby preventing the paper ejection roller pair from nipping the curled portion at the front end of the corner, effectively preventing the so-called corner folding of the recording paper. Prevented.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the thermal transfer device and paper ejection device, Fig. 2 is a rear view of the paper ejection device, Fig. 3 is a perspective view of the guide member, and Fig. 4 is an enlarged view of the main parts of the upper paper feeder. FIG. 5 is a schematic vertical sectional view of the entire copying machine, and FIG. 6 is a perspective view of another embodiment. FIG. 7 is a perspective view of a conventional paper ejecting device;
FIG. 8 is an explanatory diagram of a state in which the front edge of the corner of the recording paper is folded. 25, 26... Paper discharge roller, 27, 28... Paper feed guide, 29... Guide member, a... Recording paper,
l, L...width.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A plurality of pairs of upper and lower paper ejection rollers are provided to nip and convey the recording paper at both edges and an intermediate portion in the width direction, and the plurality of pairs of paper ejection rollers are provided. In a paper ejecting device of an image forming apparatus, in which upper and lower paper feeding guides for guiding the recording paper toward the rollers are arranged so that at least the upper one forms a vertical rib between the rollers, the front edge of the corner of the recording paper is A paper ejection device for an image forming apparatus, characterized in that a guide member is provided to guide the nip portion of the pair of paper ejection rollers. (2) A paper ejection device for an image forming apparatus according to claim (1), wherein the guide width of the guide member is larger than the nip width of the pair of paper ejection rollers. . (3) Paper ejection of the image forming apparatus according to claim (1), wherein the guide width of the guide member is accommodated within the nip width of the pair of paper ejection rollers. Device. (4) The image forming apparatus according to claim 1, wherein the guide member is configured to guide the upper surface side of the front end of the corner of the recording paper. paper equipment.