JPH05270713A - Paper feeding device of image formation device - Google Patents

Abstract

PURPOSE:To freely change curvature of a sheet at the time of inversion in accordance with the kind of paper by constituting a guide member free to revolve around the center of curvature of a guide part as its center in a device reversing the sheet after picture processing by a curved guide part forming a part of the guide member and discharging it. CONSTITUTION:A reversing sheet feeding part 8 of an image formation device has a guide member consisting of an inside guide member 17 and an outside guide member 18, and a discharge tray part 9 is integrally provided on the extensional part of the inside guide member 17. In this case, a shaft 19 is passed through the inside of the inside guide member 17 having a semicircular curved guide part 17a and integrated through the guide part 17a and a segment 20. In the meantime, on the outside guide member 18, support pieces 22, 23 are provided at positions on upstream and downstream sides and shafts 24, 25 are respectively passed through them. Thereafter, the outside guide part 18 is moved with the shaft 24 through an arm plate 21 by rotation of the shaft 19 at the time of lifting the discharge tray part 9, inclination of the discharge tray part is changed and simultaneously, curvature of the discharged sheet is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device of an image forming apparatus.

[0002]

2. Description of the Related Art The sheets stacked in the lower portion of the image forming apparatus main body are sequentially fed, and after image processing, the sheets are reversed by being sent along the curvature of the guide portion that is a part of the guide member, so that the image forming apparatus external body There is an image forming apparatus having a reversing type paper discharge tray, for example, having a mechanism for discharging to the paper discharge tray.

.. On the other hand, there is a technique in which the upper part of the device can be opened and closed with one end side as a fulcrum to facilitate maintenance and inspection of the internal structure (Japanese Patent Laid-Open No. 60-83045).
See JP-A-62-8596. )

[0004]

SUMMARY OF THE INVENTION A low speed machine, a small copying machine,
Image forming apparatuses such as printers are desired to be smaller and lighter. For example, with regard to the technology related to the above-mentioned conventional technology provided with a reversing type paper ejection tray, if the height of the apparatus is lowered, the curvature of the guide is inevitably increased, and the paper cannot be conveyed when the fed paper is thick. become.

On the other hand, if the curvature of the guide portion is reduced, it is possible to reversely convey thick paper, but this is against the demand for size reduction and weight reduction of the apparatus.

Therefore, if the design is made in response to the demands for downsizing and weight reduction of the device, the paper size, the paper quality, etc. are limited, and it becomes difficult to design a product group that meets the needs of the customer.

The above-mentioned prior art does not provide any solution to the problem in the reversing type discharge tray.

An object of the present invention is to feed a sheet of an image forming apparatus, which enables good feeding regardless of the type of sheet to be fed, and which can be made compact and lightweight. To provide a device.

[0009]

In order to achieve the above object, the present invention has any one of the following configurations.

(1). The guide member is configured to be rotatable around the center of curvature of the guide portion or in the vicinity thereof, and the curvature when the sheet is reversed and discharged is changed according to the sheet type.

(2). In (1), the guide and the discharge tray are integrally formed.

(3). In (1), the guide member is
An inner guide member and an outer guide member, and a moving means for moving the downstream side of the outer guide member in a direction away from the inner guide member when the inner guide member rotates. Paper feeding device of image forming apparatus.

[0013]

The guide member can be raised and lowered, and when it is tilted, the curvature of the guide becomes large (for thin paper), and when it is raised, the curvature of the guide becomes small (for thick paper).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 6 which illustrates the overall structure of an image forming apparatus to which the present invention is applied, reference numeral 1 indicates a main body, inside which various devices are formed.

That is, the sheets stacked in the replaceable sheet feeding cassette 2 are sent by the sheet feeding roller 3, the conveying roller 4, etc., and are sent to the transfer section 5 arranged around the photosensitive drum 10. The image is transferred by, and further separated from the photoconductor drum 10 by the separation unit 6 to reach the fixing device 7, where after fixing, after exiting the conveying roller 16, it passes through the reversing paper feeding unit 8 and the discharge tray. It is discharged to the part 9.

Around the photosensitive drum 10, a transfer section 5,
In addition to the separating unit 6, a main charger 11, a developing device 12, a cleaning device 13, a charge eliminating lamp 14 and the like are arranged.
An exposure unit is provided on the photosensitive drum between the main charger 11 and the developing device 12, and light including image information is irradiated and scanned through the rotary polygon mirror 15, the mirror M, and the like. An electrostatic latent image is carried on it.

A guide member is provided in the reversing sheet feeding section 8. In this example, this guide member is composed of three lines and is composed of an inner guide member 17 and an outer guide member 18, and these are composed of wire rods in order to reduce the weight as shown in FIG. Further, the extension portion of the inner guide member 17 is integrated with the discharge tray portion 9.

Referring to FIG. 1, a shaft 19 penetrates a position inside the curved inner shape of the inner guide member 17 having a semicircular curved guide portion 17a. This axis 19
Both ends of the are pivotally supported by a body side plate (not shown) after penetrating the arm plate 21. The arm plate and the shaft are fixed to each other in the penetrating portion.

The guide portion 17a has a shaft 19 on the inner side thereof.
Are fixed via the segment 20. Therefore,
When the shaft 19 is rotated, the inner guide member 17 is rotated together with the paper discharge tray portion 9 accordingly.

The outer guide member 18 is made of an elastic wire and has a larger radius than the guide portion 17a. By being provided outside the guide portion 17a and concentrically with the curved shape of the guide portion 17a, A gap serving as a sheet conveyance path is formed between the guide portion 17a and the guide portion 17a.

A support piece 22 is fixed to the downstream side of the outer member 18 on the downstream side in the sheet conveying direction, and a support piece 23 is fixed to the upstream side of the outer member 18. Each support piece 22 provided on the three guide portions 17a is penetrated by a shaft 24. Both ends of the shaft 24 are pivotally attached to the arm plate 21.

On the other hand, each support piece 23 is penetrated by a shaft 25. As shown in FIG. 5, both ends of the shaft 25 are engaged with elongated holes 26 formed in the body side plate.

By supporting the shafts 24 and 25, a gap between the inner guide member and the outer guide member, which serves as a sheet conveyance path, is maintained.

At the exit of this gap, a pair of paper transport rollers 27 is provided. Each roller is fixed to shafts 28 and 29, and both ends of each shaft are pivotally supported by the arm plate 21.

Of these shafts, a pulley 29 is fixed to the shaft 29 on the shaft end side and inside the arm plate 21. Further, a pulley 31 is rotatably provided at a position on the shaft 19 facing the pulley 30 with respect to the shaft, and the pulley is rotated by the power of a drive source (not shown). This allows
The roller 27 is rotated in the paper transport direction.

In FIG. 1, the paper discharge tray portion 9 is slightly inclined with respect to the horizontal plane and is in the state of the inclination angle A shown in FIG. This state is held by the lower limit stopper 32 that contacts the lower surface of the arm plate 21.

With the state shown in FIG. 2 as a reference, as the paper discharge tray 9 is lifted upward, the shaft 19 rotates via the segment 21, and together with this, the arm plate 2
1 rotates.

With this rotation, the outer guide member 18 moves together with the shaft 24, but the free end side thereof has the shaft 25 and the slot 2.
The movement of the inner guide plate 17 is restricted by the engagement relationship with the inner guide plate 6, so that the inner guide plate 17 escapes to the outside as shown in FIG.

As a result, as shown in FIG. 5, the interference between the outer guide member 18 and the fixed guide 33 due to the raising of the paper discharge tray portion 9 is avoided.

In this way, FIG. 3 shows a steeply inclined state in which the paper discharge tray portion 9 is raised, and the inclination angle is A '. This steeply inclined state is held by the circular recess 21a formed in the arm plate 21 being elastically spread by a pin (not shown) and then returning to the closing direction as shown in FIG. 1 to surround and engage the pin. It In order to properly perform such engagement and holding, the arm plate 21 may be made of elastic synthetic resin.

As is clear from a comparison between FIGS. 2 and 3, the curvature of the sheet that is reversed and sent to the sheet discharge tray section 9 is smaller in the state of FIG.

Therefore, when a thick sheet is stacked in the sheet feeding cassette 2 (see FIG. 6), if the sheet discharging tray 9 is used in a raised state as shown in FIG. Is well done. In this case, the discharge tray unit 9
However, since this is a temporary state,
It does not increase the size of the device itself.

Contrary to the above case, when thin paper, such as plain paper, is stacked in the paper feeding cassette 2, the sheet shown in FIG.
It is used with the paper ejection tray unit 9 tilted as shown in FIG.
In this case, the curvature of the paper at the reversing portion is large, but the paper is thin and therefore can be conveyed without any problem.

Since the driving source of the roller 27 is carried out via the pulley 31 attached to the shaft 19 which is a common rotation center, the roller 2 is irrespective of the rotation position of the guide member.
The rotation of 7 is well maintained.

The position of the shaft 19 may coincide with the center of the guide portion 17a, but the position is not necessarily limited thereto, and may be displaced from the center. Incidentally, in the example of FIG. 5, the position of the shaft 19 is slightly left of the center O of the guide portion 17a,
And it is defined below.

In this way, when the shaft 19 is removed from the center of curvature of the guide portion 17a, the apparent radius of curvature seen from the main body changes before and after the rotation.

Incidentally, as shown in FIG.
In a state in which is lifted, a situation occurs in which the upstream end of the guide portion 17a intersects with the upper fixed guide 34. In order to prevent interference due to such a state, as shown in FIG. 4, a notch 35 is formed at a portion corresponding to each guide portion 17a at the downstream end of the upper fixed guide 34.
Should be formed.

[0038]

According to the present invention, an image forming apparatus capable of being satisfactorily fed regardless of the type of sheet to be fed, and being capable of reducing the size and weight of the apparatus. It is possible to provide the sheet feeding device.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a main part of a configuration according to the present invention.

FIG. 2 is a front view when the guide member is tilted.

FIG. 3 is a front view when a guide member is raised.

FIG. 4 is a diagram illustrating a means for avoiding interference between an upper fixed guide and an inner guide member.

FIG. 5 is a diagram illustrating a configuration for expanding the outer guide member.

FIG. 6 is a diagram illustrating an overall configuration of an image forming apparatus according to the present invention.

[Explanation of symbols]

 17 inner guide member 18 outer guide member

Claims (3)

[Claims] 1. Papers stacked in the lower portion of an image forming apparatus main body are sequentially fed, and after image processing, the papers are reversed by being fed along the curvature of a guide portion which is a part of the guide member, so that the image is reversed. In an image forming apparatus having a mechanism for discharging to a discharge tray outside the main body of the forming apparatus, the guide member is configured to be rotatable around the center of curvature of the guide portion or in the vicinity thereof, and the curvature at the time of reverse sheet discharge is set. A sheet feeding device of an image forming apparatus, which can be changed according to a type. 2. A sheet feeding device of an image forming apparatus according to claim 1, wherein the guide and the discharge tray are integrally formed. 3. The guide member according to claim 1, wherein the guide member includes an inner guide member and an outer guide member, and the downstream side of the outer guide member is separated from the inner guide member as the inner guide member rotates. A sheet feeding device of an image forming apparatus, comprising a moving unit that moves the sheet in a predetermined direction.