JP2947980B2 - Paper ejection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper discharge device for an image forming apparatus such as a laser printer, a copying machine, a facsimile or the like using an electrophotographic process.

[0002]

2. Description of the Related Art FIG. 1 is a schematic structural view of a conventional laser printer.

A recording sheet 2 pressed from a sheet feeding device 1 to a pickup roller by a bottom plate raising lever and fed in the direction of a registration roller is timed by a registration roller pair 3 to form a latent image formed of a drum-shaped photosensitive member 4. It is transported to the image carrier. The photoconductor 4 is driven to rotate counterclockwise as viewed in the figure, and the surface thereof is charged by the charger 5 at that time.
Irradiation with laser light from the laser optical system 6 forms an electrostatic latent image on the photoconductor. This latent image is visualized by toner when passing through the developing device 7, and this visible image is transferred to the recording paper 2 conveyed to the photoreceptor 4 by the transfer charger 8, and the visible image on the transferred recording paper is transferred. Is fixed by the fixing device 9. On the other hand, the residual toner is removed from the photoconductor 4 after the transfer of the visible image by the cleaning device having the cleaning blade 10. The toner removed from the photoconductor 4 is collected and stored in a toner collection tank 12.
The recording paper 2 discharged from the fixing device 9 is stored in the paper discharge unit 11 as it is for single-sided recording, and is guided to a pair of double-sided conveying rollers 14 by a rotatable double-sided entrance guide 13 for double-sided recording. . The recording paper 2 is conveyed by the pair of double-sided conveyance rollers 14 to the pair of reversing rollers 15 rotating so as to feed the recording paper 2 in the direction of the paper feeding device.
Pass through. After a predetermined period of time after the recording paper 2 has passed the reversing sensor 16, the reversing roller pair 15 changes the rotating direction, and switches the rotatable reversing guide 17 to convey the recording paper 2 in the registration roller pair direction. The recording paper 2 fed again to the registration roller pair 3 is conveyed to the photoconductor 4 at a timing by the registration roller pair 3, and the toner image is transferred and fixed to the recording paper 2 through the same procedure as described above. . At this time, since the opposite side to the case where the sheet is fed from the sheet feeding device 1 is in contact with the photoconductor 4, double-sided recording is performed on the recording sheet 2. After passing through the fixing device 9, the recording paper 2 on which double-sided recording has been performed is discharged to the paper discharge unit 11 by the double-sided entrance guide 13 and stored.

[0004]

In recent years, especially in laser printers and the like, there has been an increasing demand for printing not only on ordinary recording paper, that is, so-called cut paper, but also on envelopes. However, when comparing the cut paper and the envelope, the weight per sheet depends on the size and material, but the cut paper (A4 size) is generally 3.7 to 5.6 g, whereas the penetration rate Despite the fact that an envelope with a high thickness is almost the same as 3-5.5 g, the thickness of the cut paper is 0.1%.
mm, the envelope is about 1 mm, which is about 10 times the difference. If the flap part of the envelope is open,
The envelope becomes thicker than that. In addition, the width of the cut paper is 210 to 216 mm, whereas the width of the envelope is 90 to 120 mm, which is almost a half difference.

[0005] Therefore, when envelopes are stacked on the paper discharge tray, the number of envelopes becomes one-tenth or less of cut sheets and becomes full.

Therefore, when printing on an envelope, it is required that an appropriate stack be formed.

In order to improve the stacking performance of cut paper, for example, a paper discharge device provided with a paper discharge tray that can be lowered according to the amount of copy paper, as disclosed in Japanese Utility Model Laid-Open Publication No. 60-19551, A paper discharge tray for stacking recording paper like a paper receiving device described in Japanese Patent Laid-Open No. 62-27273 in which the number of sheets accommodated is increased by displacing the sheet horizontally with a spring or the like as the number of sheets accommodated increases. On the side,
There is a style in which the stack amount is adjusted by weight. This will be described with reference to a paper discharge tray having a conventional structure shown in FIG.
The spring 23 flexes and the bottom plate 22 swings according to the stack weight of the cut paper.

However, in such a paper discharge tray, although the stacking performance of cut paper can be improved, as described above, the envelope has a weight that is substantially the same as that of the cut paper. When the envelopes are stacked, for example, in the case of cut paper, when the bottom plate 22 sinks by 15 mm, 100 sheets, about 4 sheets are required.
If you need 60 g and 10 mm in thickness, envelope 2
In the case of 0, a thickness of 100 mm is required. As shown in FIG. 3, the bottom plate 22 does not move much compared to the thickness of the stack, and when the number of sheets is 1/10 or less of the cut sheet, However, the fullness detector 24 provided in the vicinity of the discharge outlet operates without exerting the movable function of the bottom plate, and the number of stacks cannot be increased. That is, the above-mentioned request cannot be met.

[0009] Even in a paper ejection device described in Japanese Utility Model Laid-Open Publication No. 1-143756, in which a paper entry prevention mechanism is provided in a paper ejection tray that can be moved up and down by a spring or the like to eliminate stacking defects, printing is performed on envelopes. In some cases, proper stacking cannot be performed.

Therefore, an object of the present invention is to improve the stacking performance in any of cut paper and envelope.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem by providing a paper discharge device having a paper discharge tray provided with a bottom plate movable in accordance with a load amount, in a discharge device having an elastic force in accordance with the load amount. A swingable first bottom plate, and a second bottom plate inside the second bottom plate that is capable of swinging against the elastic force according to the load capacity, and the elastic force at the first bottom plate is The problem was solved by adjusting it to be larger than the elastic force at

It is more preferable to provide a connecting means for integrally swinging the first bottom plate and the second bottom plate.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on an embodiment shown in the drawings.

FIGS. 4 and 5 show a discharge tray according to the present invention. The boss of the U-shaped bottom plate 25 with the spring 26 as the first bottom plate is fitted with the boss of the bottom plate 27 for the envelope with the spring 28 for the second bottom plate. Bottom plate 2
7 swings with respect to the U-shaped bottom plate 25. As a result, as shown in FIGS. 6 and 7, the stack amount of the envelope can be increased several times as compared with the related art. Also, a U-shaped bottom plate 2 provided on the paper discharge tray
5 and the envelope bottom plate 27 can be integrated by sliding the clip 29 as a connecting means attached to the U-shaped bottom plate 25 inward. When stacking the cut sheets, the springs 26 and 28 flex and the integrated bottom plates 25 and 27 swing according to the stack weight of the cut sheets, so that the stack amount of the cut sheets can be increased.

[0020]

[0021]

[0022]

[0023]

According to the first aspect of the present invention, the first bottom plate can be swung against the elastic force according to the load amount, and the first bottom plate is located inside the first bottom plate against the elastic force according to the load amount. A movable second bottom plate is provided, and since the elastic force at the first bottom plate is adjusted to be larger than the elastic force at the second bottom plate, when thick and narrow envelopes are stacked. Can be stacked on the second bottom plate with small elasticity, and when thin and wide cut paper is stacked, it can be stacked on the first bottom plate with large elasticity, cut paper, In any case of the envelope, the stack performance can be improved.

[0025]

[0026]

[0027]

[0028]

[0029]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a conventional laser printer.

FIG. 2 is a schematic perspective view of a conventional bottom plate movable paper discharge tray.

FIG. 3 is a schematic diagram showing a state in which envelopes are stacked on a paper discharge tray of FIG. 2;

FIG. 4 is a conceptual diagram of an assembly of a paper discharge tray according to the present invention.

FIG. 5 is a schematic perspective view of the paper discharge tray of FIG.

FIG. 6 is a schematic end view showing a state in which envelopes are stacked on the paper discharge tray of FIG. 4;

FIG. 7 is a schematic perspective view corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Paper discharge part 18 Paper discharge conveyance roller pair 20 Envelope 21 Paper discharge tray 25 Bottom plate 26 Spring 27 Bottom plate for envelope 28 Spring for envelope 29 Clip

Claims (2)

(57) [Claims] A first bottom plate capable of swinging against an elastic force according to the load amount, and a first bottom plate inside the discharge device having a discharge tray provided with a bottom plate movable in accordance with the load amount. At least one second bottom plate capable of swinging against the elastic force in accordance with the load amount, so that the elastic force at the first bottom plate is larger than the elastic force at the second bottom plate. A paper ejection device characterized by being adjusted. 2. The sheet discharging device according to claim 1, further comprising a connecting means for integrally swinging the first bottom plate and the second bottom plate.