JPH0930708A - Recording material ejector - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To properly discharge and stack recording materials onto a stacking tray. Discharge means for discharging a sheet while keeping the shape in which the center in the width direction is convex upward or downward, and the center in the width direction according to the shape of the discharged sheet A sheet ejecting device, which is capable of being placed in a shape that is convex upward or downward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material discharging device for an image forming apparatus that employs an electrostatic recording method, an electrophotographic recording method, or the like.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus such as a copying machine and a printer, an apparatus employing an electrophotographic recording system has been widely used.

The periphery of the recording material discharging device in such an electrophotographic apparatus is constructed as shown in FIG. The recording material P on which the toner image is fixed by the fixing device 9 is separated from the fixing roller 91 and the pressure roller 92, and then passes through the conveyance guide plates 93 and 94, and the discharge roller pair 101 and 102.
Are discharged to the outside of the machine body H by the stack tray 110. Here, when the recording material is conveyed to the discharge roller pair, the recording material P is elastically urged against the flange portion 101F of the drive roller conveying portion 101T of the discharge roller and the drive roller as shown in FIG. By the driven roller 102, the recording material is conveyed while being wavy in the recording material conveyance direction.

[0004]

However, the above-mentioned conventional example has the following problems.

First, in the method of locally forming the waist by the flange portion 101F of the driving roller conveying portion 101T and the driven roller 102, the waist forming effect on the entire recording material is small, and the recording material having a weak waist, especially after fixing is fixed. When discharging a transparency for OHP, etc., a pair of discharge rollers 101, 1
02 and the stack tray 110 buckle greatly,
The buckled recording material may interfere with the ejection of the recording material that is conveyed next, and in the worst case, paper jam may occur (see FIG. 12).

Secondly, a recording material having a large basis weight, specifically 2
As shown in FIG. 11, in order to locally attach the paper of about 00 g / m ² to the flange portion of the driving roller conveying portion and the driven roller, the urging force of the driven roller needs to be about several hundred grams per place. However, due to this urging force, the recording material having a weak stiffness, specifically, the paper of about 60 g / m ² and the transparency for OHP are strongly sandwiched between the driving roller conveyance portion and the driven roller, and become a recording material. This causes a problem of disturbing the image of. Especially in the case of transparency, which is shortly after fixing, when the roller is hitting the outside air while passing through the discharge roller and is solidifying together with the toner, it largely undulates due to the pressing force of the driven roller, and its shape is memorized after discharge and irradiated on the OHP. In that case, a part floating from the OHP platen glass becomes defocused.

In view of the above-mentioned drawbacks, the present invention has the object of not disturbing an image even on a recording material having a weak waist,
That is, it is possible to satisfactorily discharge and stack on a stacking tray.

[0008]

Means for solving the above-mentioned problems include means for discharging a sheet while maintaining a shape such that the center in the width direction is convex upward or downward, and a discharging means. According to the shape of the sheet when it is discharged, the sheet discharging apparatus is characterized in that the sheet discharging apparatus has a mounting unit capable of mounting the sheet in a shape in which the center in the width direction is convex upward or downward.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) The first embodiment of the present invention will be described in detail below.

FIG. 1 is a perspective view of the periphery of a recording material discharging device according to a first embodiment of the present invention, showing a transparency A4 size T.
FIG. 7 is a diagram illustrating a state where the sheet is being conveyed with the longitudinal direction being the conveying direction.

The sheet or recording material P on which the toner image is fixed by the fixing device 9 is a fixing roller 91 and a pressure roller 92.
After being separated from the driving roller 101, it is gripped and conveyed by the driving roller 101 that rotates in the direction of the arrow by the driving method shown in the drawing through the conveyance guide plates 93 and 94 and the driven roller 102 that is elastically biased against the driving roller. , And is discharged to a stacking tray 110 as a stacking unit supported by a machine body (not shown).

Next, the driving roller and the driven roller which constitute the discharging means of this embodiment will be described with reference to FIG.

The driving roller has 50-100 mm of two recording material conveying portions 101T made of rubber material with respect to the shaft 101J.
They are integrally formed apart from each other. A flange portion 101 having an outer diameter d _f is provided on the central portion side of the recording material at the recording material conveying portion.
F is formed, and a cylindrical portion 101C having a long outer diameter of φd _c is formed on the outer side of the F, and a taper shape 101S is formed on the outer side of the cylindrical portion 101C up to the outer end of the recording material conveying portion (outer diameter φd _s ).
The relationship between the respective outer diameters is d _f > d _c > d _s . Although not shown, the driven roller 102 is urged to the drive roller cylindrical portion 101C by a pressing method using a leaf spring or the like.
The urging force is set to about 10 g to 50 g / one place, and even when a recording material such as a transparency is conveyed immediately after the weak fixing, the recording is performed by the driving roller cylindrical portion and the driven roller as shown in FIG. Make sure the material is not pinched.

Due to the shape of the driving roller and the urging force of the driven rollers as described above, the transparency T is conveyed while forming a convex arc shape in a cross section perpendicular to the recording material conveying direction as shown in FIG. Further, as shown in FIG.
A rib 111C having a height of about 5 to 8 mm and a rib 111S having a height of about 2 to 4 mm, which is provided in a central portion in a direction perpendicular to the recording material conveying direction of 0, and has a height of about 5 to 8 mm, is separated from both sides by about 100 mm. By installing in the same direction, even if the transparency T being discharged comes into contact with the stacking tray, the discharging can be completed without buckling while maintaining the arc shape that is convex upward in the entire conveying direction.

When a large amount of toner is fixed on the recording material T of a color copying machine or the like, the recording material largely curls downward (two-dot chain line in FIG. 3). As a result, the curl can be corrected (solid line in FIG. 3) by the weight of the recording material being applied downward (in the direction of the arrow in FIG. 3) on both sides of the cross section perpendicular to the conveying direction of the recording material.

A rib 111 on the loading surface of the loading tray is used.
C and 111S may be attached to and detached from the stacking tray, and may be installed only at the time of discharging a recording material having weak stiffness such as transparency. Further, the stacking tray in this embodiment may have an upward convex V-shaped cross section in the direction perpendicular to the recording material conveying direction as shown in FIG. 4 or an upward convex arcuate shape not shown.

A color image forming apparatus using the above-described discharging device will be described with reference to FIG.

This example has a digital color image reader section in the upper part and a digital color image printer section in the lower part.

In the reader unit, the original 30 is placed on the original table glass 31 and exposed and scanned by the exposure lamp 32, so that the reflected light image from the original 30 is condensed by the lens 33 on the full-color sensor 34, and color images are obtained. Obtain a decomposed image signal. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to a printer unit.

In the printer section, the photosensitive drum 1 which is an image bearing member is rotatably supported in the direction of the arrow, and a pre-exposure lamp 11, a corona charger 2, a laser exposure optical system 3 and a potential sensor 12 are provided around the photosensitive drum 1. , Four developing devices 4y, 4c, 4m, 4Bk of different colors, on-drum light amount detecting means 1
3. The transfer device 5 and the cleaning device 6 are arranged.

In the laser exposure optical system 3, the image signal from the reader unit is converted into an optical signal by a laser output unit (not shown), the converted laser light is reflected by the polygon mirror 3a, and the lens 3b and the mirror. It is projected onto the surface of the photosensitive drum 1 through 3c.

When forming an image on the printer section, the photosensitive drum 1
Is rotated in the direction of the arrow to uniformly charge the photosensitive drum 1 after charging by the pre-exposure lamp 11 by the charger 2, and irradiate the light image E for each separation color to form a latent image.

Next, a predetermined developing device is operated to develop the latent image on the photosensitive drum 1 to form a resin-based toner image on the photosensitive drum 1. The developing device has an eccentric cam 24.
The operations of y, 24c, 24m, and 24Bk make it possible to selectively approach the photosensitive drum 1 in accordance with each separation color.

Further, the toner image on the photosensitive drum 1 is
The transfer device 5 for transferring to the recording material supplied from the recording material cassette 7 to the position facing the photosensitive drum 1 via the conveying system and the transfer device 5 is, in this example, a transfer drum 5a, a transfer charger 5b, and a recording material. In the peripheral opening area of the transfer drum 5a, which has an attraction charger 5c for electrostatic attraction, an attraction roller 5g, an inner charger 5d, and an outer charger 5e which face each other, and which is rotatably supported by the transfer drum 5a. The recording material carrying sheet 5f made of a dielectric material is integrally stretched in a cylindrical shape. The recording material supporting sheet 5f uses a dielectric sheet such as a polycarbonate film.

As the drum-shaped transfer device, that is, the transfer drum 5a is rotated, the toner image on the photosensitive drum is transferred onto the recording material carried on the recording material carrying sheet 5f by the transfer charger 5b.

In this way, a desired number of color images are transferred to the recording material that is adsorbed and conveyed to the recording material carrying sheet 5f to form a full color image.

In the case of forming a full-color image, when the transfer of the four color toner images is completed in this way, the recording material is separated from the transfer drum 5a by the action of the separation claw 8a, the separation push-up roller 8b and the separation charger 5h, and the heat is generated. The sheet is discharged onto the tray 110 via the roller fixing device 9.

On the other hand, after the transfer, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned by the cleaning device 6.

When images are formed on both sides of a recording material,
Immediately after the fixing device 9 is discharged, the transport path switching guide 19 is driven, and after being guided to the reversing path 21a through the transport vertical path 20, the reverse end of the reversing roller 21b causes the trailing end when fed to the beginning. Then, it is withdrawn in the direction opposite to the direction in which it was fed and is stored in the intermediate tray 22. After that, an image is formed on the other surface by the above-described image forming step.

Further, in order to prevent the powder from being scattered on the recording material-carrying sheet 5f of the transfer drum 5a and the oil on the recording material being adhered, the brush is provided via the fur brush 14 and the recording material-carrying sheet 5f. 14, a backup brush 15 facing the sheet 14, an oil removing roller 16 and a recording material carrying sheet 5
Cleaning is performed by the action of the backup brush 17 that faces the roller 16 via f. Such cleaning is performed before or after image formation. Also, jam (paper jam)
When it occurs, it will be done at any time.

Further, in this example, the eccentric cam 25 is operated at a desired timing and the cam follower 5i integrated with the transfer drum 5f is actuated so that the gap between the recording material carrying sheet 5a and the photosensitive drum 1 is reduced. The configuration can be set arbitrarily. For example, during standby or when the power is off, the interval between the transfer drum and the photosensitive drum is increased.

(Second Embodiment) FIG. 5 is a perspective view of the periphery of a recording material discharging apparatus according to a second embodiment of the present invention, showing a state in which a transparency A4 size T is being conveyed with its longitudinal direction being the conveying direction. is there.

Since the basic structure of this embodiment or the color image forming apparatus adopting this embodiment is the same as that of the first embodiment, the description thereof will be omitted.

Next, the drive roller and driven roller of this embodiment will be described with reference to FIG.

The drive roller 101 is formed integrally with a shaft 101J and two recording material conveying portions 101T made of a rubber material. A flange portion 101F having an outer diameter d _f is formed on the recording material end portion side of the recording material conveying portion, a long cylindrical portion 101C having an outer diameter φd _c is formed inside thereof, and the recording material conveying portion center is further inside thereof. A tapered shape 101S is formed up to the side end (outer diameter φd _s ). The relationship of each outer diameter is d _f >
d _c > d _s .

Although not shown, the driven roller 102 is a driving roller cylindrical portion 101C by a pressing method using a leaf spring or the like.
The urging force is 10g to 50g / 1.
Even if the recording material such as transparency is set immediately after fixing with a weak stiffness, the recording material is not pinched by the driving roller cylindrical portion and the driven roller as shown in FIG. To

By the driving roller shape and the driven roller urging force as described above, the transparency T is conveyed while forming a downward convex arc shape in a cross section perpendicular to the recording material conveying direction as shown in FIG.

Further, on the stacking surface of the stacking tray as shown in FIG. 5, ribs 111 having a height of about 5 to 8 mm are arranged parallel to the recording material conveying direction at positions of about 40 to 60 mm on both sides from the central portion in the recording material width direction. Even if the transparency T being discharged comes into contact with the stacking tray, the discharge can be completed without buckling while maintaining the arcuate shape in which the entire conveying direction is convex downward.

According to the stacking tray of this embodiment,
Since the central portion of the discharged recording material bends downward due to its own weight, there is also an advantage that the width direction of the next discharged recording material easily conforms to the width of the previously discharged recording material and the consistency of the recording material is good. . The rib 111S on the stacking tray stacking surface may be detachable from the stacking tray, and may be installed only when discharging a recording material having weak stiffness such as transparency. Further, the stacking tray according to the present embodiment may have a downward convex V shape or a downward convex circular arc shape whose cross section in the direction perpendicular to the recording material conveyance direction is the opposite direction to that shown in FIG. good.

(Third Embodiment) FIG. 7 is a perspective view of the periphery of a recording material discharging device according to a third embodiment of the present invention, showing a state in which a transparency A3 size T is being conveyed with its longitudinal direction being the conveying direction. is there.

The basic structure of this embodiment and the color image forming apparatus adopting this embodiment are the same as those in the first embodiment, and the explanation thereof is omitted.

Next, the drive roller and the driven roller of this embodiment will be described with reference to FIG.

The drive roller 101 is integrally formed with four recording material conveying portions 101T and 101T 'made of a rubber material on the shaft 101J. Among the recording material transporting portions, two flanges 101F on the central side in the axial direction are formed with a flange portion 101F having an outer diameter d _f on the central portion side of the recording material, and a long cylinder having an outer diameter φd _{c on} the outer side thereof. The taper shape 101S is formed on the portion 101C and further on the outer side thereof to the outer end portion (outer diameter φd _s ) of the recording material conveyance portion. The relationship between the respective outer diameters is d _f > d _c > d _s . Next, of the recording material conveyance parts,
Two axially outer side portions 101T 'are formed with flange portions 101F' having an outer diameter d _f ′ at both end portions thereof, and a long cylindrical portion 101C 'having an outer diameter φd _c ′ is formed inside thereof.
It has a shape. The relationship between the respective outer diameters is d _f ′> d _c ′.
And d _f ′ <d _f . Although not shown, the driven roller 102 is urged to the drive roller cylindrical portion 101C by a pressing method using a leaf spring or the like, and the urging force is 10 g.
Even if the recording material such as transparency is set at about 50 g / 1 place and immediately after fixing with weak stiffness, the recording material is nipped by the driving roller cylindrical portion and the driven roller as shown in FIG. Try not to. Due to the shape of the driving roller and the urging force of the driven rollers as described above, in the case of a relatively narrow recording material which is conveyed with the longitudinal direction of the recording material T _s of A4 size or the like, the driving is performed as shown in FIG. Recording material conveying portion 101T on the center side of the roller in the recording material width direction
When a relatively wide recording material T ₁ such as A3 size is conveyed, the recording material is conveyed by using all the recording material conveying portions 101T and 101T ′ of the driving roller as shown in FIG. It can be transported while forming a large arc shape that is convex upward in a cross section perpendicular to the direction. Further, as shown in FIG. 7, the height of the stacking tray is 5 to 8 mm in the direction parallel to the conveying direction, which is provided in the central portion in the direction perpendicular to the recording material conveying direction.
Even if the transparancy T being discharged is in contact with the stacking tray, the entire rib 111C and the ribs 111S having a height of 2 to 4 mm are installed in the same direction at positions 100 mm apart from both sides of the rib 111C. It is possible to complete the discharge without buckling while maintaining the upwardly convex arc shape. By adding the driving portion of the driving roller and the driven roller as in the present embodiment, it is possible to increase the material of the recording material that can be discharged without lowering the image quality and obtaining a sufficient feeding force.

As described above, according to the recording material discharging apparatus of the present invention, the driving roller and the driven roller cause the recording material to have a large convex upward or downward convex cross-section in the direction perpendicular to the recording material conveying direction. Since the recording material is conveyed in a shape and is maintained by the cross-sectional shape of the stacking tray in the direction perpendicular to the recording material conveying direction until the recording material is completely discharged, it is possible to prevent the recording material from buckling on the stacking tray. Further, according to the first embodiment, in addition to the effect of the first embodiment, the recording material is ejected in a convex shape on the stacking tray and is discharged and the shape thereof is maintained, so that a large lower curl due to the contraction of the toner is generated. When it occurs, the curl can be corrected by the weight of the recording material.

According to the second embodiment, the recording material is ejected onto the stacking tray in a convex downward shape, so that the next recording material ejection position is easily aligned with the position of the previously ejected recording material. Excellent material consistency.

According to the third embodiment, the drive roller is divided into at least two portions forming the recording material conveying surface in the axial direction, so that the recording material can be efficiently raised by the conveying portion having a small volume. Or you can sit down in a convex shape.

According to the fourth embodiment, since a large pressure is not locally applied to the recording material, the image quality of the recording material is not deteriorated.

[Brief description of drawings]

FIG. 1 is a perspective view around a recording material discharging device according to a first embodiment.

FIG. 2 is a cross-sectional view of a recording material discharging unit according to the first embodiment.

FIG. 3 is a perspective view showing effects of the recording material discharging device according to the first embodiment.

FIG. 4 is a perspective view around a recording material discharging device according to the first embodiment.

FIG. 5 is a perspective view around a recording material discharging device according to a second embodiment.

FIG. 6 is a cross-sectional view of a recording material discharging unit according to the second embodiment.

FIG. 7 is a perspective view around a recording material discharging device according to a third embodiment.

FIG. 8 is a cross-sectional view of a recording material discharging unit according to a third embodiment.

FIG. 9 is a schematic sectional view of a color image forming apparatus of the present invention.

FIG. 10 is a cross-sectional view around a recording material discharging device in a conventional image forming apparatus.

FIG. 11 is a perspective view around a recording material discharging device in a conventional image forming apparatus.

FIG. 12 is a perspective view showing a problem in the conventional discharging device.

[Explanation of symbols]

T recording material 100 recording material discharging device 101 driving rollers 101T, 101T 'driving roller conveying portion 102 driven roller 110 stacking tray 111 stacking tray rib d _f driving roller conveying portion flange outer diameter d _s driving roller conveying portion end outer diameter

Claims (5)

[Claims] 1. A driving roller, one of which is driven to rotate,
In the recording material discharging device of the image forming apparatus, which has a discharging means for discharging the recording material and a stacking tray for stacking the discharged recording material, the driven roller is the recording material. The roller diameter in the vicinity of the central portion in the axial direction is the largest, and the central portion in the recording material width direction of the cross section of the stacking tray stacking surface perpendicular to the recording material conveying direction has the highest shape. Recording material discharge device. 2. A driving roller, one of which is driven to rotate,
In the recording material discharging device of the image forming apparatus, which has a discharging means for discharging the recording material and a stacking tray for stacking the discharged recording material, the driven roller is the recording material. The roller diameter in the vicinity of the central portion in the axial direction is the smallest, and the central portion in the recording material width direction of the cross section of the stacking tray stacking surface perpendicular to the recording material conveying direction has the lowest shape. Recording material ejecting device. 3. The drive roller is characterized in that a recording material conveying portion forming a recording material conveying surface is divided in the axial direction from a center of the recording material width direction to at least two or more positions substantially at a target position. The recording material discharging device according to claim 1 or 2. 4. The recording material discharging apparatus according to claim 1, wherein the driven roller is biased against the driving roller by a force that does not abruptly deform the recording material in a narrow range. 5. A discharging unit that discharges a sheet while keeping a shape in which a center in the width direction is convex upward or downward, and a width direction in accordance with a shape when the discharged sheet is discharged. A sheet discharging device, comprising: a mounting unit that can be mounted with the center thereof being convex upward or downward.