JPH05306041A - Paper sheet sensor - Google Patents

Abstract

PURPOSE:To prevent a copying belt and a lever from being caught mounting/ demounting, by forming a tapered part downward in the front surface direction on an actuator lever for paper sensor which projects from the upper surface of a paper transport device so as to be set along the copying belt mounting/ demounting direction. CONSTITUTION:A paper transporting device 18 is constituted of a plurality of conveyor belts 18a which shift in the paper transport direction B and a paper sensor 19 arranged therebetween. The paper sensor 19 is an optical sensor using an actuator 23, and is constituted of a shutter 23b for cutting off the light supplied from a light projector, and an actuator lever 23a which directly contacts a paper sheet, and is pivotally supported by a supporting shaft 24. In this case, on the actuator lever 23, a tapered part 23a' is formed downward in the front surface direction, so as to be set along a copying belt mounting/ demounting direction. Accordingly, when the copying belt is mounted/demounted, the copying belt is shifted along the tapered part 23a', and is prevented from being caught.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet detection sensor in an electrophotographic apparatus such as a copying machine.

[0002]

2. Description of the Related Art As shown in FIG. 7, a sheet conveying device 42 in an electrophotographic apparatus such as a copying machine has a drum-shaped photosensitive member 31.
Intermediate transfer device 33 having transfer belt 39 pressed against
Is disposed below.

A charging charger for charging the surface of the photoconductor is provided around the drum photoconductor 31.
A developing tank 32 for supplying the toner of the toner image formed on the surface of the photoconductor is provided. An intermediate transfer device 33, which is in pressure contact with the photosensitive member 31, is arranged below the photosensitive member 31. The intermediate transfer device 33 has an endless transfer belt 39, and the transfer belt 39 is rotationally driven. The rollers 34 to 38 are stretched. Further, the transfer belt 39 is sandwiched between a roller 34 and a transfer roller 40 arranged so as to face the roller 34, and a paper feed tray (not shown) is provided between the transfer roller 40 and the transfer belt 39. Alternatively, a copy sheet (hereinafter referred to as a copy sheet) sent from the sheet feed cassette is carried in by the transport roller 41.

On the unloading side of the transfer roller 40 and the intermediate transfer device 33, there is provided a paper transfer device 42 for transferring the copy sheet on which the toner image is transferred from the transfer belt 39 to the fixing device 45. .. This paper transport device 42
A paper detection sensor 43 is provided in the paper.

A fixing device 45 having fixing rollers 46 for heating and melting the toner to fix the toner on the copy sheet is disposed on the unloading side of the paper conveying device 42. An unloading roller 47 for unloading the fixed copy sheet is disposed on the unloading side of the fixing device 45.

As shown in FIG. 6, the sheet conveying device 42 has conveying belts 42a, 42a for conveying copy sheets.
a is provided, and the paper detection sensor 43 is provided between the two conveyor belts 42a. The paper detection sensor 43 has an actuator 44 (FIG. 5), and for example, an optical sensor is used. In this actuator 44, an actuator lever 44a on the upper side of the actuator is provided from an opening provided on the upper surface of the paper conveyance device 42. It is provided so as to project.

As shown in FIG. 5, the actuator 44 has a rod-shaped actuator lever 44a which is in direct contact with the copy sheet, and a triangular shape for cutting off the light emitted from a light emitter (not shown) to the light receiver. And a shutter 44b of the actuator 44, and is rotatably supported by the sheet conveying device 42 by a support shaft 44c provided substantially at the center of the actuator 44.

[0008]

When the copying machine is used for a long time, each part in each device needs to be replaced because it is damaged or worn out. For example, the transfer belt 39 of the intermediate transfer device 33 may be replaced due to damage or wear. In this case, it is necessary to remove the transfer belt 39 and replace it with a new transfer belt 39.

However, since the size and the positional relationship of each unit of the copying machine are substantially determined by the size of the copying machine body and the copying process, as shown in FIG. 7, for example, the intermediate transfer device 33 and the sheet conveying device 42 are used. The size of the space between and is also limited. Therefore, when the transfer belt 39 of the intermediate transfer device 33 is attached or detached, the rod-shaped actuator lever 44a protruding above the upper surface of the sheet conveying device 42 often comes into contact with the transfer belt 39. When such contact occurs, the end portion of the transfer belt 39 is moved to the actuator lever 44.
It may get caught in a. In such a case, since the actuator 44 is rotated by a light copy sheet, the strength of the actuator lever 44a is not necessarily large, the end portion of the transfer belt 39 bends the actuator lever 44a, and the support shaft of the actuator 44 is bent. There are many troubles such as a bend of 44c or a flaw on the transfer belt 39.

Therefore, there is a problem that a flaw in the transfer belt 39 causes a transfer failure, or a damage of the actuator 44 causes a paper detection failure.

Further, if a trouble occurs when the transfer belt 39 is attached or detached as described above, there is a problem in that replacement work of the transfer belt 39 takes time and labor, and workability is deteriorated.

The present invention has been made in view of the above problems, and an object of the present invention is to eliminate transfer failure and paper detection failure due to damage of the transfer belt or actuator lever when the transfer belt is attached and detached, and to attach and detach the transfer belt. It is an object of the present invention to provide a paper detection sensor provided in a paper conveyance device that can easily perform the above.

[0013]

SUMMARY OF THE INVENTION A sheet conveying device of the present invention is a sheet detecting device disposed in front of the transfer belt of an electrophotographic apparatus such as a copying machine having an endless transfer belt as an intermediate transfer member. In the sensor, the actuator lever protruding from the upper surface of the sheet conveying device is provided with a taper portion downward in the front direction so as to be along the attachment / detachment direction of the transfer belt.

[0014]

With the above structure, when the transfer belt is attached or detached, even if the transfer belt and the actuator lever come into contact with each other, the transfer belt may move along the shape of the tapered portion of the actuator lever and be caught by the actuator lever. Therefore, the transfer belt can be easily attached and detached without damaging the actuator lever and the transfer belt, and the workability of the transfer belt replacement can be improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 4, for example, the paper detection sensor according to the present embodiment has a color copy mode and a monochrome copy mode for copying a document image in a single color, and a full-color copy for faithfully reproducing the color of the document image for copying. It is built in the paper transporting device 18 such as a full-color copying machine which is an electrophotographic device capable of executing the mode.

The above-mentioned full-color copying machine has a transparent original placing table 1 on its upper surface, and an original 2 to be copied is placed on the original placing table 1. An exposure optical system 3 is arranged below the document table 1, and the exposure optical system 3 exposes a document 2 placed on the document table 1 with an exposure lamp 3a. A plurality of reflecting mirrors 3b for guiding the reflected light from the original 2 to the photoconductor 4 as shown by a broken line, and an image forming lens 3c arranged on the optical path.
And a color separation filter (not shown) having color filters of three primary colors of red, green, and blue.

Below the exposure optical system 3, a photoconductor 4 to which the above-mentioned reflected light is irradiated is arranged. The photoconductor 4 is in the form of a drum, and around the periphery thereof, there are provided developing tanks 5 for supplying toner to be attached onto the surface of the photoconductor 4. The developing tanks 5 are not in contact with the photoconductor 4, and the developing tanks 5 are individually filled with black and white developers, cyan, yellow and magenta developers for color copying. Has been done. In addition to the developing tanks 5 around the photoconductor 4, a charger 7 for charging the photoconductor 4 and a cleaning device 8 for removing toner remaining on the surface of the photoconductor 4 are provided. And are provided. A sheet feeding unit 9 and a sheet feeding cassette 10 are provided on the lower right side of the charger 7 and the cleaning device 8.

On the other hand, below the photoconductor 4, an intermediate transfer device 6 is arranged. The intermediate transfer device 6 has an endless transfer belt 6a, and the transfer belt 6a is a roller for rotational driving. It is stretched by 12 to 16 and pressed against the photoconductor 4. The transfer belt 6a is sandwiched between the rotation driving roller 12 and a transfer roller 17 arranged so as to face the roller 12, and the transfer belt 6a is interposed between the transfer roller 17 and the transfer belt 6a. Is a paper feed tray or paper feed cassette 1 (not shown) provided in the paper feed unit 9.
The copy sheet carried out from 0 is carried in through the carrying system 11.

On the unloading side of the transfer roller 17 and the intermediate transfer device 6, there is provided a paper transport device 18 for transporting a copy sheet on which a toner image corresponding to the original 2 has been transferred. A fixing device 20 that heats and melts the toner to fix the toner on the copy sheet is disposed on the carry-out side of 18. The fixing device 20 is provided with fixing rollers 21 and 21 for heating and fusing and fixing the toner of the copy sheet conveyed from the paper conveying device 18, and the fixing side of the fixing device 20 has a fixing roller 21. The carry-out rollers 22 and 22 for discharging the copy sheet are provided.

As shown in FIG. 2, the sheet conveying device 18 conveys the transferred copy sheet to the fixing device 20. Therefore, the sheet conveying device 18 conveys the conveying belts 18a and 18a which move in the advancing direction of the copy sheet, that is, the arrow B direction. Belt 18a ・ 18
It is composed of a paper detection sensor 19 provided between a and a.

The paper detection sensor 19 is, for example, an optical sensor using an actuator 23. As shown in FIG. 1, a triangular shutter 23b for blocking light from a light projector (not shown) and direct contact with the paper. And a support shaft 24 provided substantially in the center of the actuator 23, and is rotatably supported by a part of the sheet conveying device 18 (not shown).

The actuator lever 23a is connected to the conveyor belt 18a. When there is no copy sheet on 18a, the actuator lever 23a projects from the surface of the conveyor belt, and the shutter 23b blocks the light beam (not shown) of the paper detection sensor 19 so that there is no copy sheet on the conveyor belt 18a. When the copy sheet is conveyed onto the conveyor belt 18a, the actuator lever 23a is pressed against the copy sheet, the light beam of the paper detection sensor 19 is received by the light receiving device, and the copy sheet exists on the conveyor belt 18a. It is detecting that. Furthermore, the actuator lever 23
A taper portion 23a 'is provided on the front surface a downward of the transfer belt 6a so as to extend in the attaching / detaching direction of the transfer belt 6a.

Since the size and the positional relationship of each unit of the copying machine are substantially determined by the size of the copying machine body and the copying process, the intermediate transfer device 6 is constructed as shown in FIG.
It is arranged in the space between the drum-shaped photosensitive member 4 and the sheet conveying device 18. Since this space is very narrow in structure, the end portion of the transfer belt 6a of the intermediate transfer device 6 and the actuator lever 23a of the paper detection sensor 19 of the paper transport device 18 are very close to each other. There is. Therefore, when the transfer belt 6a is attached to or detached from the intermediate transfer device 6 when the transfer belt 6a is replaced, for example, the transfer belt 6a and the actuator lever 23a may come into contact with each other.

When the transfer belt 6a and the actuator lever 23a come into contact with each other in this way, in the conventional copying machine,
The transfer belt 6a is often caught on the actuator lever 23a. Further, the actuator 23 needs to be made of a light material because it needs to easily rotate even if it is made of a light material such as a copy sheet.
Therefore, since the strength of the actuator lever 23a cannot be increased, the transfer belt 6a may be flawed or the actuator lever 23a may be damaged. However, in the paper detection sensor 19 of the present invention,
By providing the actuator lever 23a for detecting the paper with a taper portion 23a 'facing downward in the front direction,
As indicated by the broken line C, when the transfer belt 6a is attached or detached, the transfer belt 6a moves along the tapered portion 23a '.

As described above, when the transfer belt 6a is attached to or detached from the intermediate transfer device 6, if the transfer belt 6a and the actuator lever 23a come into contact with each other, the transfer belt 6a moves along the tapered portion 23a 'of the actuator lever 23a. Therefore, the transfer belt 6a and the actuator lever 23a are not caught, the transfer belt 6a is not scratched by the actuator lever 23a, and the actuator lever 23a is damaged and the support shaft 24 of the actuator 23 is damaged, so that the actuator 23 is not damaged. It does not come off from the paper transport device 18. Therefore, the transfer failure due to the flaw of the transfer belt 6a is eliminated, and the actuator lever 23a is damaged.
Paper detection failure due to bending of the support shaft 24 of the actuator 23 is eliminated.

Further, since the actuator lever 23a and the transfer belt 6a are not caught when the transfer belt 6a is attached or detached, the intermediate transfer device 6 for the transfer belt 6a.
The transfer belt 6a can be easily attached to and detached from, and the workability in exchanging the transfer belt 6a can be improved.

[0028]

As described above, the sheet detecting sensor of the present invention is a sheet disposed in front of the transfer belt of an electrophotographic apparatus such as a copying machine having an endless transfer belt as an intermediate transfer member. In the detection sensor, the actuator lever protruding from the copy sheet conveyance path is provided with a taper portion downward in the front direction so as to follow the attachment / detachment direction of the transfer belt.

Therefore, when the transfer belt is attached to or detached from the main body of the copying machine, the transfer belt moves along the taper portion provided on the actuator lever, so that the transfer belt does not get caught when the transfer belt is attached or detached. No damage or damage to the actuator lever or actuator support shaft. Therefore, the transfer failure due to the flaw of the transfer belt is eliminated, and the paper detection failure due to the damage of the actuator can be eliminated.

Further, since the transfer belt can be easily attached and detached, the workability of exchanging the transfer belt can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of an actuator of a sheet detection sensor incorporated in a sheet conveyance device of the present invention.

FIG. 2 is a perspective view when the actuator shown in FIG. 1 is attached to a sheet conveying device.

3 is a cross-sectional view of the cross section taken along the broken line A in FIG.

FIG. 4 is a front view showing a schematic configuration of a copying machine of this embodiment.

FIG. 5 is a perspective view showing an actuator of a conventional paper inspection sensor.

FIG. 6 is a perspective view when the actuator of FIG. 5 is attached to a sheet conveying device.

FIG. 7 is a schematic front view of a main part of a conventional copying machine.

[Explanation of symbols]

 6a Transfer belt 18 Paper transport device 19 Paper detection sensor 23a Actuator lever 23a 'Tapered portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutoshi Kawai 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (1)

[Claims] 1. A paper detection sensor arranged in the front direction of the transfer belt of an electrophotographic apparatus such as a copying machine having an endless transfer belt as an intermediate transfer member,
A sheet detection sensor, characterized in that an actuator lever protruding from the upper surface of the sheet conveying device is provided with a taper portion downward in the front direction so as to extend along the transfer belt attachment / detachment direction.