JP2548406B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a laser beam printer and a copying machine, and more particularly to the structure of a discharged paper stacking tray.

(B) Conventional technology Conventionally, in a printer or the like having an automatic double-sided printing function, since it is necessary to form an image on a large number of sheets, there is a large difference between the discharge stack tray and the discharge means, and a wide tray is also formed. As a result, the sheet is allowed to fall freely onto the tray from the sheet discharging means.

(C) Problems to be Solved by the Invention However, in the case of the above-described configuration, the sheets falling from the sheet discharging means onto the tray having a large drop are not well aligned on a wide tray, and the front and rear and left and right sides have 20 to 20 Some of them are overhanging by 30 mm, and they are stacked on the tray separately, so that there is a drawback in that when binding, it is necessary to spend much more time to align them.

Therefore, it is an object of the present invention to provide an image forming apparatus having a discharge stacking tray that can improve sheet stacking performance by providing a guide member for dropping sheets.

(D) Means for Solving the Problems The present invention has been made in view of the above circumstances, and discharges the sheet on which an image is formed in the image forming unit from the discharge unit to the discharge stack tray. In the image forming apparatus for stacking, the discharged paper stacking tray has a stacking surface that has an upward slope toward the downstream in the sheet discharging direction from the discharging unit, and a guide member that rises from the lower end of the stacking surface. The guide member is centered around a position where the leading edge of the sheet discharged from the discharging unit comes into contact with the stacking surface or a sheet stacked on the stacking surface, or a position downstream from the position in the sheet discharging direction. The sheet has a circular arc surface, and the trailing edge of the sheet, which is separated from the discharging means, is guided by the guide member and falls onto the stacking surface.

(E) Operation Based on the above configuration, the leading edge of the sheet discharged from the discharging means contacts the stacking surface or the sheet stacked on the stacking surface. Then, as soon as the trailing edge of the sheet comes off the discharging means, the sheet falls onto the stacking surface or the already stacked sheet while the trailing edge of the sheet is guided by the arc surface of the guide member.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is a laser beam printer,
A scanner unit 2 is provided on the upper right side in the drawing, and its light beam irradiates the photosensitive drum 3a of the image forming unit 3 housed in the cartridge.

Further, cassettes 4 and 5 containing sheets P are mounted on the right side portion, and the cassettes 4 and 5 are provided with paper feed and double feed prevention rollers 6 and 7, respectively. The sheet P is conveyed to the registration rollers 10 via 9. Then, the photosensitive drum 3a and this photosensitive drum
A transfer roller 11 that faces 3a is disposed, and then a fixing device 13 is disposed on the left side of the printer 1 via a guide plate 12.

Further, a flapper 14 is provided in the vicinity of the left side of the fixing device 13, a guide is provided above or below by this flapper 14, and a paper discharge roller 15 is provided at the upper guide end. A paper discharge tray 16 is formed on the upper surface of the printer 1. Also, at the end of the lower guide 17, the transport roller 18
Is provided.

Further, following the carrying roller 18, a re-feeding guide 19 is provided at the bottom left side of the printer 1, a carrying roller 20 is provided at the downstream end of the guide 19, and a flapper 21 is provided near the roller 20. Has been.

A conveyance path 22 that restricts the width direction of the sheet P is provided at the bottom of the printer 1 on the right side of the flapper 21, and a forward / reverse roller 23 that switches back the sheet P on the conveyance path 22 is provided. Then, a guide for guiding the sheet P from the flapper 21 to the registration roller 10 above.
A transport roller 25 is provided above the guide 24 and its guide 24.

Then, the top of the paper discharge tray 16 will be described in more detail.

Letting T be the landing point at which the leading edge of the sheet P discharged onto the paper ejection tray 16 first lands, let R be the distance from the landing point T to the paper ejection roller 15, and the back of the tray 16 is regulated. The plate 16a is formed in an arc surface having a radius R or more.

By doing so, the regulation plate 16a is an inclined surface that is directed obliquely forward.

Since the present embodiment is configured as described above, the sheets P fed one by one from the cassette 4 or 5 by the paper feed / double feed prevention roller 6 or 7 are skew-regulated by the registration roller 10 and exposed. The image is transferred to the sheet P in synchronism with the drum 3a, and is fixed by the fixing device 13, and the flipper is used.
Guided by 14.

Here, when the image is formed only on the upper surface of the sheet P, the flapper 14 is conveyed in the direction of arrow C in the posture of the solid line display, and is ejected to the paper ejection tray 16 by the paper ejection roller 15.

When an image is formed on the back surface of the sheet P,
In the state where the flapper 14 is indicated by the broken line, the flapper 21 is conveyed in the direction of the arrow D, is conveyed to the re-feeding guide 19 by the conveyance roller 18 via the curved guide 17, and is temporarily stopped, and then the flapper 21 is indicated in the state where the broken line is indicated. After being conveyed to the conveyance path 22 by the conveyance rollers 20 and being regulated in the width direction of the sheet P here, it is switched back by the reverse rotation of the forward / reverse rotation rollers 23, and the flapper 21 is guided upward in the state where the solid line is displayed. It is guided to 24 and is guided by the transport roller 25.
The image is transferred from the photosensitive drum 3a to the back surface of the sheet P by the registration roller 10 as described above, is fixed by the fixing device 13, and the flapper 14 is shown by the arrow C in the solid line posture. Is conveyed in the direction, and is ejected and stacked on the ejection tray 16 by the ejection roller 15.

Further, the discharge tray 16 will be described in detail. The sheet P discharged from the discharge roller 15 has its leading end landing first in the vicinity of the landing point T, and the trailing end of this sheet P faces a little diagonally forward. Are aligned while being pushed out, and stored one by one.

Next, another embodiment will be described with reference to FIGS. 2 and 3.

In the present embodiment, a paper aligning arm 26 is rotatably supported by the apparatus main body 1a near the upper part of the paper discharge roller 15, and a paper pressing roller 26a which is not too heavy is rotatably attached to the tip of the arm 26. Then, the leading end of the discharged sheet P is pressed.

As a result, when the sheet P is discharged from the paper discharge roller 15, the leading end of the sheet P is lightly pressed by the paper pressing roller 26 and conveyed under the roller 26a, and the sheet P is discharged.
The rear end freely falls along the regulation plate 16a. That is, since the front and rear ends of the sheet P are fixed and stacked on the tray 16, the sheets P are stacked on the discharge tray 16 in an orderly manner even when the apparatus body 1a is vibrating.

(G) Effect of the Invention As described above, according to the present invention, the discharged paper stacking tray has a simple structure having a guide member that rises to the lower end of the stacking surface, and has a large drop from the discharging means. Although a large number of sheets can be stacked by stacking the sheets, the rear ends of the sheets are guided by the arcuate surface of the guide member and are stacked on the stacking surface in an orderly manner, so that the storability of the sheets can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional side view showing an essential part of another embodiment, and FIG. 3 is a plan view of FIG. 1 ... Image forming device (laser beam printer), 3 ...
Image forming unit, 15 ... Paper discharging means (paper discharging roller), 16 ... Paper discharging tray (paper discharging tray), 16a ... Guide member (regulating plate), P ... Sheet, T ... Landing position (Landing point).

Claims (1)

(57) [Claims] 1. A sheet on which an image is formed by an image forming unit,
In the image forming apparatus that discharges from the discharging unit and stacks on the discharged sheet stacking tray, the discharged sheet stacking tray has a stacking surface that has an upward slope toward the downstream side in the sheet discharge direction from the discharging unit, and the stacking surface. A guide member that rises from the lower end of the sheet, and the guide member is near or at a position where the leading edge of the sheet discharged from the discharging unit contacts the stacking surface or the sheet stacked on the stacking surface. An image having an arc surface centered on a position on the downstream side in the sheet discharging direction, and the trailing edge of the sheet that has deviated from the discharging unit is guided by the guide member and drops onto the stacking surface. Forming equipment.