JPH09156838A - Paper sheet housing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the existence of the paper sheet inside of an intermediate tray by detecting a fall of a paper sheet presser member into a slit when the paper sheet does not exist in a bottom plate of a paper sheet tray in an oscillating member, which is fitted to a telescopic shaft crossing the paper sheet carrying direction and which is formed with the paper sheet presser member. SOLUTION: A bottom plate 8a of an intermediate tray 8 is formed with a slit 28 for inserting a paper sheet presser member 27 of an oscillating member 22 along the paper sheet carrying direction. A photo sensor 29 is fitted to the bottom plate 8a of the intermediate tray 8 at a position near the slit 28. When a rear end of a paper sheet passes through the position of the paper sheet presser member 27, the paper sheet presser member 27 is fallen into the slit 28, and the photo sensor 29 is turned off, and non-existence of the paper sheet inside of the intermediate tray 8 is detected. With this structure, even a curled paper sheet can be housed in the intermediate tray without generating housing failure and paper jam, and the image forming productivity can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet accommodating apparatus used in a copying machine or a printer, and more particularly to a sheet accommodating apparatus having an intermediate tray used for double-sided image formation or multiple image formation.

[0002]

2. Description of the Related Art For example, in a copying machine capable of double-sided copying, a sheet of paper in a paper feed tray is conveyed toward an electrophotographic image forming section, and a toner image on an image carrier is printed on the first side of the sheet. The image is formed on the first surface of the sheet by being transferred. The sheet on which the image is formed on the first side is subjected to a fixing process, and then the front side and the reverse side are reversed and once accommodated in the intermediate tray. Next, the paper in the intermediate tray is conveyed again to the image forming unit, the image is formed on the second surface of the paper, and the fixing process is performed again. In this way, images are formed on both sides of the paper. Further, in the case of multiple image formation, images are formed on the same side of the paper a plurality of times.

[0003]

When a sheet having an image formed on its first surface is subjected to a fixing process, the sheet passes through a fixing device composed of a heating roller and a pressure roller. Curls under heat and pressure. For this reason, when the sheet on which the image is formed on the first surface is stored in the intermediate tray, the sheet cannot be stored in the intermediate tray in a normal posture, and the sheet may not be stored properly, or the sheet may be caught in the intermediate tray and stored. There was a problem of causing clogging.

On the other hand, in the above-mentioned copying machine capable of double-sided copying, it is necessary to provide a paper sensor for detecting the presence / absence of paper in the intermediate tray in order to control the timing of the image forming operation. When using a mechanical sensor using an actuator that directly contacts the paper as disclosed in Japanese Utility Model Laid-Open No. 2-69679, it is necessary to sufficiently consider the position where the sensor is installed. Is inappropriate, the actuator will resist the transport of the paper and the paper will not be stored correctly in the intermediate tray, or a paper feed error will occur when the paper is re-fed from the intermediate tray. There is also a problem that the presence or absence of paper cannot be detected correctly.

Therefore, it is an object of the present invention to provide a paper storage device that can correctly store even curled paper in an intermediate tray. Another object of the present invention is to provide a paper storage device capable of correctly detecting the presence / absence of paper in the intermediate tray.

[0006]

A paper accommodating apparatus of the present invention is located above a paper carrying-in side of a paper tray and has a shaft extending in a direction orthogonal to the paper carrying direction, and a shaft which is free with respect to the shaft. A swinging member that is rotatably attached to the paper and has a sheet pressing member formed of an arcuate plate-like body that has a surface parallel to the sheet transport direction at its free end and is pushed up by the sheet being transported. A slit provided on the bottom plate of the paper tray so that the paper pressing member of the swing member can be depressed when no paper is present in the paper tray; and the slit provided near the slit. And a sensor for detecting that the paper pressing member is depressed.

Further, the swing member is arranged near the reference position of the paper tray.

Further, a part-cylindrical stopper wider than the paper pressing member is provided on the base end side of the paper pressing member of the swing member.

Further, a weight attaching portion for attaching weights having different weights in a replaceable manner is provided on the base end side of the rocking member with respect to the sheet pressing member.

Further, the paper tray is an intermediate tray for accommodating fixed paper for double-sided image formation or multiple image formation.

[0011]

1 is a schematic diagram showing a schematic configuration of an image forming apparatus to which a sheet accommodating apparatus of the present invention is applied.

In the figure, a plurality of paper feed trays 1a to 1e are provided inside a housing of the image forming apparatus, and a paper feed device 2 provided corresponding to each of the paper feed trays 1a to 1e.
By operating any one of a to 2e, the paper is sent out from the desired paper feed tray. Paper tray 1a
The sheet sent from any one of to 1e is conveyed along the sheet conveying path A by the sheet conveying device 3.

An electrophotographic image forming section 4 is arranged on the top of the casing of the image forming apparatus. Image forming unit 4
Includes a photoconductor drum 4a, and a charging device 4b, an exposure device 4c, a developing device 4d, a transfer device 4e, a cleaning device 4f, etc., which are sequentially arranged around the photoconductor drum 4a. Then, a toner image is formed on the photosensitive drum 4a by known electrophotographic processes of charging, exposing, and developing.

Further, the photosensitive drum 4a and the transfer device 4
A pre-registration roll 5a, a registration gate 6, and a registration roll 5b are arranged in the upstream portion of the image transfer portion where e is opposed. The paper conveyed along the paper conveyance path A is
The sheet is conveyed by the pre-registration roll 5a, the leading edge of the sheet is abutted against the registration gate 6 to position the leading edge of the sheet, and then the rotation of the pre-registration roll 5a is stopped. Then, the registration gate 6 is opened at the timing of forming the toner image on the photosensitive drum 4a,
The paper is sent out along the path B by the registration roll 5b. Then, the sheet on which the toner image is transferred is fixed by the fixing device 7, and in the case of single-sided image formation, the path C is used.
It is discharged toward a discharge tray or the like via. Further, when performing double-sided image formation, the single-sided image-formed sheet is conveyed via the path D and stored in the intermediate tray 8.

In the intermediate tray 8, the sheet is conveyed by a conveying device 9 composed of a plurality of conveying roller pairs, and further, a belt wound around a conveying roll 10 and a sheet reversing roll 11 (not shown in FIG. 1). As a result, the sheet is conveyed along the J-shaped reversing chute 12, the front and back of the sheet are reversed, and the first side on which the image has been formed faces upward.
Is stored inside. The details of the structure of the intermediate tray 8 will be described later.

Next, the paper in the intermediate tray 8 is conveyed by a paper feed roll (not shown in FIG. 1), the leading end of the paper is abutted against the gate 13, and the leading end of the paper is positioned. After that, the rotation of the paper feed roll is stopped.
Next, the gate 13 is opened and the paper feed roll is rotated, so that the paper in the intermediate tray 8 is re-fed along the paths E and A. Next, an image is formed on the second surface of the sheet through the path B, similarly to the first surface, the image is fixed through the fixing device 7, and the image is discharged toward the discharge tray or the like through the path C.

Next, the structure of the intermediate tray 8 will be described in detail.

FIG. 2A is a schematic sectional view showing a main part of the intermediate tray 8 used in the sheet accommodating apparatus of FIG. A transport belt 14 is wound around the transport roll 10 and the sheet reversing roll 11, and a pinch roll 15 is pressed against the transport belt 14 at the position of the transport roll 10. The intermediate portion of the conveyor belt 14 is sandwiched by the roller pairs 16 and 17.

A paper feed arm 19 is attached to the rotary shaft 18 of the paper reversing roll 11 in a state in which it can freely move up and down about the rotary shaft 18. The paper feed arm 19 is vertically driven by a solenoid (not shown). Further, the paper feeding arm 19 includes an intermediate tray 8
A paper feed roll 20 that conveys the paper inside, and a power transmission mechanism 21 including a plurality of gears for transmitting the rotational force from the rotary shaft 18 to the paper feed roll 20 are attached.

A pendulum-shaped swing member 22 is rotatably attached to the rotary shaft 18 of the paper reversing roll 11. 3A, 3B and 3C show the swing member 2
2 is a plan view, a front view, and a side view of FIG. Swing member 22
A through hole 23 for inserting the rotary shaft 18 is formed at the base end of the, and a partially cylindrical stopper 24 is formed at the tip. The width of the swing member 22 is from the base end to the stopper 24.
Up to, for example, a constant width of 10 mm. A hollow tubular weight attaching portion 25 is integrally formed inside the partially cylindrical stopper 24, and a columnar weight 26 is fitted into the weight attaching portion 25 and attached. As the weight 26, a plurality of types having different weights are prepared and can be exchanged as needed. Below the stopper 24, a paper pressing member 27 made of, for example, an arc-shaped thin plate having a thickness of 2 mm is integrally formed.

On the other hand, the bottom plate 8a of the intermediate tray 8 is shown in FIG.
As shown in (b), a slit 28 for inserting the sheet pressing member 27 of the swing member 22 is formed along the sheet conveying direction. An interrupter-type photo sensor 29 is attached to the bottom plate 8 a of the intermediate tray 8 at a position near the slit 28. FIG. 4 (a),
(B) And (c) is the top view, front view, and side view of the photosensor 29. The photo sensor 29 includes a light emitting unit 31 and a light receiving unit 32 that are arranged to face each other with a gap 30 having a constant width. The photo sensor 29 includes the light emitting unit 3
The gap 30 between 1 and the light receiving portion 32 is arranged at a position where the sheet pressing member 27 of the swinging member 22 passes, and when the sheet pressing member 27 is located above the bottom plate 8a of the intermediate tray 8, When the light from the light emitting unit 31 enters the light receiving unit 32, the photo sensor 29 is turned on, and the sheet pressing member 27 is located below the bottom plate 8a of the intermediate tray 8, the light from the light emitting unit 31 is emitted. And the photo sensor 29 is turned off. That is,
The paper pressing member 27 also functions as an actuator for the photo sensor 29.

A paddle member 33 is provided near the outlet of the reversing chute 12 as shown in FIG. As shown in FIG. 6, the paddle member 33 is fixedly arranged on the shaft 33a at a predetermined interval and has a pair of discharge rollers 33c having flat knurled grooves 33b formed on the outer peripheral surface thereof.
And a pair of paddles 33e made of an elastic body provided axially symmetrically on the mounting portion 33d provided between the pair of discharge rollers 33c so as to project outward. The shaft 33 a is supported by a support member 34 and is elastically pressed against the sheet reversing roll 11.

On the exit side of the intermediate tray 8, that is, on the right end side in FIG. 2, a feed roll 35 and a retard pad 36, which constitute a paper separating mechanism, are arranged.

Further, a skew roller 37 is provided above the intermediate portion in the intermediate tray 8. The skew roller 37 can be moved up and down by an elevating drive mechanism (not shown), and can be rotationally driven in the arrow direction by a rotational drive mechanism (not shown).

Next, the operation of the above-mentioned sheet accommodating device will be described.

In the initial state, since there is no sheet in the intermediate tray 8, the sheet pressing member 2 of the swinging member 22 is not present.
7 has fallen into the slit 28, and the photo sensor 29 is off. At this time, the stopper 24 contacts the bottom plate 8a of the intermediate tray 8 to regulate the lower limit position of the swing member 22. Further, the paper feed arm 19 is driven to a raised position indicated by a solid line by a solenoid (not shown).
Further, the rotational force from a rotary drive source (not shown) is transmitted to the rotary shaft 18 via a belt (not shown), and rotates in the arrow direction (clockwise direction in FIG. 2A).

The conveyor belt 14 is rotationally driven by the rotation of the rotary shaft 18, and the sheet conveyed by the conveyor 9 shown in FIG. 1 is sandwiched between the conveyor belt 14 and the pinch roll 15 and the conveyor belt 14 is conveyed. Is conveyed along the reversing chute 12 (see the sheet P1 in FIG. 5).
When the sheet reaches the curved portion 12a of the reversing chute 12, the sheet advances along the curved portion 12a to reverse the front and back of the sheet, and the discharge roller 33c and the transport belt provided near the outlet of the reversing chute 12 are conveyed. 14 and is discharged into the intermediate tray 8 (see the sheet P2 in FIG. 5).

The paper is discharged from the discharge roller 33c and the conveyor belt 1.
4, the front surface of the sheet and the outer peripheral surface of the discharge roller 33c are in pressure contact with each other, so that the discharge roller 33c rotates in the direction of the arrow as the sheet advances, and the pair of paddles 33
e also rotates. Therefore, when the trailing edge of the sheet comes out of the exit portion of the reversing chute 12, the trailing edge of the sheet moves toward the paddle 3.
The sheet 3e is pushed in the sheet conveying direction. As a result, the paper is forced to the back of the intermediate tray 8 (on the left side in the figure).
Therefore, the trailing edge of the sheet does not remain caught in the exit portion of the reversing chute 12. At this time, the paper feed arm 19 is in the raised position, and the paper feed roll 20 is in a state of floating from the bottom plate 8a of the intermediate tray 8.

When the leading edge of the sheet is fed into the intermediate tray 8 from the outlet of the reversing chute 12, the leading edge of the sheet pushes up the sheet pressing member 27 of the swinging member 22 to turn on the photosensor 29. This makes it possible to detect the presence of paper in the intermediate tray 8. Intermediate tray 8
The sheet fed into the sheet advances while being sandwiched between the bottom plate 8a of the intermediate tray 8 and the sheet pressing member 27 of the swinging member 22, but at this time, the upper surface of the sheet is moved by the weight of the swinging member 22. Since it can be pressed down with a constant force, even when curled paper is fed in, the paper does not float up, shift in the lateral direction, or get caught in the intermediate tray 8, and the paper is stably and reliably stored in the intermediate tray. It is housed in 8. Further, by exchanging the weight 26 of the swinging member 22, it is possible to select an optimum pressing force according to the degree of curl.

When the trailing edge of the sheet comes out of the nip portion between the conveyor belt 14 and the discharge roller 33c of the paddle member 33 at the exit of the reversing chute 12, the trailing edge of the sheet becomes
The paper is lowered by its own weight, the weight of the swinging member 22, and the paddle 33e. At this point in time, the trailing edge of the sheet remains sandwiched between the sheet pressing member 27 and the bottom plate 8a of the intermediate tray 8.

Next, the skew roller 37 descends and comes into contact with the upper surface of the sheets accommodated in the intermediate tray 8. As a result, the paper in the intermediate tray 8 is conveyed in the front right direction in FIG. 2A, the leading end of the paper is abutted against the gate 13, and the leading end of the paper is positioned.
The side edge of the sheet is abutted against a side edge reference member (not shown) to position the side edge of the sheet. After the positioning is completed, the skew roller 37 moves up.

Even at this time, since the paper pressing member 27 of the swinging member 22 is pushed up by the right end of the paper, the photo sensor 29 is still on and the paper is completely accommodated in the intermediate tray 8. In this state, the presence / absence of paper in the intermediate tray 8 can be reliably detected.

Further, since the presence / absence of the paper is detected near the reference position where the leading edge of the paper is abutted, the presence / absence of the paper in the intermediate tray 8 is surely detected regardless of the size of the paper. can do.

When re-feeding, the gate 13 is opened, the sheet reversing roll 11 is rotationally driven clockwise in FIG. 2, and the sheet feeding roll 20 is rotationally driven counterclockwise in FIG. To be done. Further, the paper feed arm 19 moves to the lowered position shown by the alternate long and short dash line, and the paper feed roll 20 contacts the upper surface of the paper stored in the intermediate tray 8.
As a result, the sheets in the intermediate tray 8 are conveyed to the right in FIG. 2, that is, in the sheet re-feeding direction. At this time,
The upper surface of the paper is pressed by the paper pressing member 27 of the rocking member 22, but the pressing force itself is a small pressure to correct the curl of the paper due to the weight of the rocking member 22,
Further, since the outer periphery of the sheet pressing member 27 has a smooth curve, the resistance force applied to the sheet is small and it does not hinder the re-feeding.

The sheet sent out from the intermediate tray 8 passes between the feed roll 35 and the retard pad 36 and is conveyed along the path A shown in FIG.

When the trailing edge of the paper passes the position of the paper pressing member 27, the paper pressing member 27 falls into the slit 28, the photo sensor 29 is turned off, and the intermediate tray 8 is turned off.
It can be detected that the paper inside is empty.

[0037]

According to the present invention, the intermediate tray is provided with the swinging member for pressing the contained sheets, and the swinging member is also used as the actuator of the photo sensor for detecting the presence or absence of the sheet in the intermediate tray. . As a result, even curled paper can be stored in the intermediate tray without causing poor storage and paper jams, and the productivity of image formation can be improved. Further, it is possible to detect the presence or absence of the paper in the intermediate tray without providing a dedicated sensor.

Further, since the swing member used as the actuator of the photo sensor for detecting the presence / absence of the paper is provided in the vicinity of the reference position where the leading edge of the paper is abutted, it is possible to accurately perform the intermediate operation regardless of the size of the paper. The presence / absence of paper in the tray 8 can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an image forming apparatus to which a sheet storage device of the invention is applied.

2A and 2B are a schematic cross-sectional view showing a main part of an intermediate tray used in the sheet storage device of FIG. 1 and a partial bottom view showing the vicinity of a slit.

3 (a), (b) and (c) are a plan view, a front view and a side view of a rocking member.

4A, 4B, and 4C are a plan view, a front view, and a side view of a photosensor.

FIG. 5 is an explanatory view showing the action of the paddle member.

FIG. 6 is a perspective view showing a paddle member.

[Explanation of symbols]

1a to 1e ... Paper feeding tray, 2a to 2e ... Paper feeding device, 3 ...
Paper transporting device, 4 ... Image forming unit, 5a ... Pre-registration roll, 5b ... Registration roll, 6 ... Regis gate, 7 ... Fixing device, 8 ... Intermediate tray, 9 ... Transporting device, 10 ... Transporting roll, 11 ... Paper reversing roll, 12 ... inversion shoot, 13
... gate, 14 ... transport belt, 15 ... pinch roll, 1
6, 17 ... Roller pair, 18 ... Rotating shaft, 19 ... Paper feeding arm, 20 ... Paper feeding roll, 21 ... Power transmission mechanism, 22 ... Oscillating member, 23 ... Through hole, 24 ... Stopper, 25 ... Weight attachment Parts, 26 ... Weight, 27 ... Paper pressing member, 28 ... Slit, 29 ... Photo sensor, 30 ... Gap, 31 ... Light emitting part, 32 ... Light receiving part, 33 ... Paddle member, 34 ... Supporting member, 35 ... Feed roll, 36 ... Retard pad, 3
7 ... Skew roller

Claims (5)

[Claims] 1. A shaft, which is located above a paper loading side of a paper tray and extends in a direction orthogonal to the paper transport direction, and is attached rotatably with respect to the shaft and at its free end. A swing member having a sheet pressing member formed of an arcuate plate-shaped body that has a surface parallel to the sheet conveying direction and is pushed up by the sheet being conveyed; and a sheet tray on the bottom plate of the sheet tray. A slit provided so that the paper pressing member of the swinging member can be depressed when no paper is present in the swing member, and it is detected that the paper pressing member is depressed in the slit provided in the vicinity of the slit. A sheet storage device comprising: a sensor. 2. The swing member is arranged near a reference position of the paper tray.
The sheet storage device described. 3. The sheet accommodating apparatus according to claim 1, further comprising a partial cylindrical stopper, which is wider than the sheet pressing member, on the base end side of the swinging member with respect to the sheet pressing member. 4. The weight attaching portion capable of exchangeably attaching weights having different weights is provided on the base end side of the rocking member with respect to the paper pressing member. Paper storage device. 5. The sheet tray according to claim 1, wherein the sheet tray is an intermediate tray for storing fixed sheets for double-sided image formation or multiple image formation. Paper storage device.