JPH11208938A - Sheet material conveying device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet material conveying device that can maintain stable detecting accuracy by suppressing the adhesion of foreign matters to a transmission type sensor, and provide an image forming device provided with this sheet material conveying device. SOLUTION: In a sheet material conveying device provided with a sheet material detecting means for detecting sheet material S by receiving light through a prism type reflecting plate 4 (light transmission member) disposed in a conveying path, a bent part 10 is provided at the conveying path near the prism type reflecting plate 4, and the conveyed sheet material S is brought into sliding contact with the prism type reflecting plate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for conveying a sheet and an image forming apparatus for forming an image on the conveyed sheet, and more particularly to an operation of a sheet detecting means provided on a conveying path. Technology for stabilizing

[0002]

2. Description of the Related Art Conventionally, as this type of apparatus, there is an image forming apparatus as shown in FIG.

[0003] The image forming apparatus comprises an image forming apparatus main body 10.
1 has a sheet feeding deck 102 in which a large amount of sheet materials S 'are stacked and stored, and a plurality of sheet feeding cassettes 103 in which a predetermined amount of sheet materials S' are stacked and stored in a lower portion inside the image forming apparatus main body 101. , 105 are provided.

Then, a sheet feeding deck 102 as a sheet feeding section for feeding the sheet material S ', and each sheet feeding cassette 1
03 and 105 are respectively provided with sheet feeders 106, 107 and 109 of retard separation type.

A paper feed deck 102, a paper feed cassette 103,
The sheet material S ′ in the paper feeder 105 is
When the sheet is fed by 107 and 109, the sheet is first sent to the registration roller pair 110 that has stopped rotating, where the skew state is corrected.

[0006] Next, the image forming means based on the well-known technique of electrophotography uses a registration roller 110 which rotates at a timing with a latent image (or a toner image) formed on the photosensitive drum 111 to form a photosensitive member. The toner image is sent between the drum 111 and the transfer charger 112, where the toner image on the photosensitive drum 111 is transferred (image formation).

After that, the sheet material S 'is conveyed to the transport belt 113.
To the fixing device (fixing roller pair) 115 to perform a fixing process for fixing the transferred toner image on the sheet surface.

The image forming apparatus has a duplex copying mode for performing duplex copying on the sheet material S 'and a multiplex copying mode for performing multiple copying. In the normal copying mode, the sheet material S' after the fixing process is not used. The paper is discharged onto a paper discharge tray 119 outside the apparatus by an external paper discharge roller pair 117.

In the case of the double-sided copy mode and the multiple copy mode, the pair of internal discharge rollers 116 or the pair of switchback rollers 127 temporarily place the image on the intermediate tray 121 via the re-feeding path 120 and the double-sided conveying path 126. It is loaded and stored.

The sheet material S 'stored on the intermediate tray 121 is again conveyed to the registration roller pair 110 for image formation by the re-feeding device 130, and thereafter discharged out of the apparatus through the same process as for one-sided copying. Is done.

Here, the paper transport path in the above-mentioned conventional example includes:
A plurality of sheet material detecting means are provided to detect the sheet material S 'conveyed at a predetermined timing,
A commonly used method is a photo-interrupter with an actuator as shown in FIG.

In the drawing, reference numeral 151 denotes an actuator; 152, a photo interrupter; 153, a paper guide which constitutes a conveyance path on which the sheet material S 'is conveyed. In this configuration, the sheet material S ′ is detected by blocking the photointerrupter 152.

However, with the recent increase in the speed and digitization of image forming apparatuses, there has been a demand for a so-called inter-sheet paper transport control technique in which the paper transport speed is high and the paper transport interval is short.

Here, when the small sheet interval control is performed on the premise of the sheet material detecting means, it becomes difficult to detect the paper position with high accuracy due to the following factors.

1. Variations in the detection area and detection time due to variations in the biasing force of the actuator biasing means (springs, etc.) and variations in assembly accuracy.

2. As shown in FIG. 10, a deviation of Amm occurs between the arrival detection position of the leading edge of the paper and the slippage detection position of the trailing edge of the paper (configuration restriction).

For the above reasons, a transmission type sensor is generally employed in order to achieve a highly accurate paper position detection.

FIG. 11 shows the principle of the transmission type sensor. In the figure, reference numeral 160 denotes a sensor main body, 161 denotes a light-emitting unit, 162 denotes a light-receiving unit, and 163 denotes a prism-type reflector. Light generated from the light-emitting unit is changed in optical path by the prism-type reflector and returns to the light-receiving unit. When the material S 'interrupts the optical path, the presence of paper is detected.

According to this configuration, since the detection accuracy of the sheet material S ′ and the leading and trailing edges is suppressed within the variation in the light beam width, it is possible to detect the paper position with extremely high accuracy.

[0020]

However, the above-mentioned prior art has the following problems.

In the transmission type sensor, as shown in FIG. 12, a sensor main body and a prism type reflection plate are arranged on opposite sides of a paper transport path, but paper dust generated by a large amount of paper passing and scattering from near the image forming means. If the suspended matter such as the toner adheres to the light emitting unit, the light receiving unit, and the prism type reflection plate and interrupts the optical path, a so-called erroneous detection trouble of detecting the presence of paper without the sheet material S 'occurs.

Conventionally, the following measures have been taken as measures against this kind of trouble.

1. Since suspended matters such as paper dust and toner tend to accumulate downward due to gravity, the location where the sensor is disposed is limited to a location where the paper transport path is oriented in the vertical direction (the vertical direction of the image forming apparatus) ( See FIG. 12). Therefore, since the sensor main body and the prism type reflection plate are inevitably arranged in the horizontal direction (the left-right direction of the image forming apparatus), it is difficult to accumulate floating matters.

2. Since the adhesion of the suspended matter does not become zero even in the above-mentioned first means, the sensor is cleaned as a regular maintenance by a service person.

3. An automatic cleaning unit for automatically cleaning the sensor unit is provided.

And the like. However, here, the means 1 restricts the degree of freedom in design of the sensor arrangement position, the means 2 increases the service cost,
Regarding the means 3, there is a concern that the cost of the apparatus will be significantly increased.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and has as its object to be applicable at a low cost without being restricted by the arrangement position of the sensor. It is an object of the present invention to provide a sheet conveying device capable of maintaining stable detection accuracy by suppressing adhesion of a foreign substance to a transmission sensor and an image forming apparatus including the sheet conveying device.

[0028]

In order to achieve the above object, according to the present invention, there is provided a conveyance path for conveying a sheet material,
Sheet material detecting means for detecting a sheet material by receiving detection light blocked or reflected by the sheet material conveyed on the conveyance path via a light transmitting member arranged on the conveyance path. In the sheet material conveying device,
A bent portion is provided in a conveying path near the light transmitting member, and a sheet material conveyed is brought into sliding contact with the light transmitting member.

Further, by receiving a conveying path for conveying the sheet material and detection light blocked or reflected by the sheet material conveyed on the conveying path via a light transmitting member disposed on the conveying path. And a sheet material detecting device for detecting the sheet material, wherein an urging means for urging the conveyed sheet material with respect to the light transmitting member on the conveying path is provided. .

It is also preferable that the urging means includes a flexible member for pressing the conveyed sheet material against the light transmitting member.

Preferably, the sheet material detecting means is a transmission type sensor including a light emitting element, a light receiving element and a reflector.

[0032] The image forming apparatus is characterized by comprising the above-described sheet material conveying device and image forming means for forming an image on the sheet material conveyed by the sheet material conveying device.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

(Embodiment 1) FIG. 1 is a schematic diagram best representing a characteristic configuration of the features of the first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a transmission type sensor main body;
Is a light emitting unit, 3 is a light receiving unit, 4 is a prism type reflector,
These constitute a sheet material detecting means for detecting the sheet material. Reference numeral 5 denotes a paper guide for guiding the sheet material conveying path H, and reference numeral 6 denotes a sensor guide.

The prism type reflection plate 4 is configured as a light transmitting member having a transparent prism function for transmitting the detection light emitted from the light emitting section 2. Further, the sensor guide 6 is also configured as a transparent light transmitting member so that the detection light emitted from the light emitting unit 2 is reflected by the prism type reflection plate 4 and can enter the light receiving unit 3. Also,
The prism type reflector 4 and the sensor guide 6 have surfaces exposed to the transport path H.

As shown in the drawing, the transport path H has a bent portion 10 having a predetermined angle near the mounting portion of the sensor guide 6.

Changes in behavior when the sheet material S passes through the conveyance path H in FIG. 1 are shown in FIGS. S in the figure is a sheet material.

As shown in the drawing, the sheet material S passes while sliding on the convex surface while following the concave surface of the bent portion 10 of the transport path H. Here, in the present embodiment, since the prism type reflector 4 is disposed on the convex side (the lower side in the figure) of the bent portion, the sheet material S always passes while sliding on the prism type reflector 4. Configuration.

With this configuration, suspended matters such as paper dust and toner temporarily adhering to the prism type reflection plate 4 are removed by the passage of the sheet material S.

In this embodiment, the prism type reflector 4 is provided on the convex side of the bent portion 10 for convenience, but it goes without saying that the same effect can be obtained by disposing the sensor body 1 on the convex side. It is preferable that the prism type reflection plate 4 and the sensor guide 6 to which the sheet material S always rubs are made of hard glass which has no problem with respect to abrasion and scratches caused by the rubbing of the sheet material S.

In the description of this embodiment, only the main portion of the transport path H of the sheet material S has been described. However, the present embodiment is provided at an appropriate position on the transport path of the image forming apparatus described with reference to FIG. With this configuration, it is possible to detect a sheet material with high position detection accuracy in the image forming apparatus.

Further, the bent portion 10 can be provided in the middle of a linearly configured transport path. In this case, a gentle bent portion is formed only in a region corresponding to the sensor body 1. It is also possible to prevent the occurrence of conveyance jam.

(Embodiment 2) FIGS. 4 and 5 show a second embodiment of the present invention.
FIG. 4 is a schematic view in which the transport path 5A is sectioned, and FIG. 5 is a view taken along the arrow BB in FIG.

4 and 5, reference numeral 1 denotes a transmission type sensor main body, 2 denotes a light emitting unit, 3 denotes a light receiving unit, 4 denotes a prism type reflector,
5A is a paper guide, and 6 is a sensor guide, which has the same configuration as in the first embodiment. However, the transport path H is formed straight without the bent portion 10, and the sheet material detecting means is disposed there.

Reference numeral 7 denotes a flexible guide as an urging means or a flexible member.

As shown in the figure, the flexible guide 7 is provided between the left and right paper guides 5A in the vicinity of the transmission type sensor mounting portion P1, and is disposed at a position separated from the sensor main body 1 by a predetermined amount in the thrust direction. I have.

FIGS. 6 and 7 show changes in behavior when the sheet material S passes through the flexible guide 7 shown in FIG. S in the figure is a sheet material.

As shown in the figure, the sheet material S passes along the urging surface 7a by the urging force of the flexible guide 7. Here, in the present embodiment, since the prism type reflection plate 4 is disposed on the biasing surface 7a side of the flexible guide 7, the sheet material S always passes while sliding on the prism type reflection plate 4. Configuration.

With this configuration, suspended matters such as paper dust and toner temporarily adhering to the prism type reflection plate 4 are removed by passing the sheet material.

In this embodiment, the prism type reflector 4 is disposed on the urging surface 7a side of the flexible guide 7 for convenience.
It goes without saying that the same effect can be obtained by disposing the sensor main body 1 on the biasing surface 7a side of the flexible guide 7.

It is desirable that the prism type reflection plate 4 and the sensor guide 6 on which the sheet material S is constantly rubbed are made of hard glass which has no problem with respect to abrasion and scratches caused by the rubbing of the sheet material.

It is desirable that the material of the flexible guide 7 should be a material having high durability such as a metal leaf spring or a highly wear-resistant film.

Here, it goes without saying that both the first embodiment and the second embodiment can be used in combination, so that the versatility of the transmission sensor is further increased.

[0055]

As described in the embodiment of the present invention, the sliding contact accompanying the conveyance of the sheet material prevents foreign matter from adhering to the light transmitting member disposed on the conveyance path, and the maintenance of the sheet material detection means is free. Thus, stable detection accuracy can be maintained.

The bent portion or the urging means for sliding the sheet material to the light transmitting member according to the present invention can be applied irrespective of the conveying direction and the curvature of the conveying path, and the restriction on the arrangement position of the sensor. It can be easily applied with a simple configuration, and has high versatility.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a transport path in the vicinity of a transmission type sensor arrangement portion applied to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a sheet material conveyance state according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing a state of conveying a sheet material according to the first embodiment of the present invention.

FIG. 4 is a schematic view of a transport path in the vicinity of a transmission type sensor disposition portion applied to a second embodiment of the present invention.

FIG. 5 is a view on arrow BB in FIG. 4;

FIG. 6 is a schematic view showing a sheet material being conveyed according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram showing a state of conveying a sheet material according to a second embodiment of the present invention.

FIG. 8 is a sectional view of the main body of the image forming apparatus provided with a sheet material conveying path.

FIG. 9 is an explanatory view of the configuration of a conventional sheet material detecting means of a photo-interrupter type with an actuator.

FIG. 10 is an operation explanatory view of a conventional photointerrupter system with an actuator.

FIG. 11 is a diagram illustrating the principle of a conventional transmission sensor.

FIG. 12 is a diagram illustrating a state in which a conventional transmission sensor is provided on a vertical transport path.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission-type sensor main body 2 Sensor light-emitting part 3 Sensor light-receiving part 4 Prism-type reflective plate (light transmission member) 5 Paper guide 6 Sensor guide (light transmission member) 7 Flexible guide (biasing means, flexible member) 10 Bend H Transport path S Sheet material

Claims (5)

[Claims] 1. A conveyance path for conveying a sheet material, and detection light blocked or reflected by the sheet material conveyed on the conveyance path is received via a light transmitting member disposed on the conveyance path. A sheet material detecting device for detecting a sheet material, comprising: a bent portion in a transfer path in the vicinity of the light transmitting member, and sliding the sheet material conveyed to the light transmitting member. A sheet material conveying device, characterized in that: 2. A conveyance path for conveying a sheet material, and a detection light blocked or reflected by the sheet material conveyed on the conveyance path is received via a light transmission member disposed on the conveyance path. A sheet material transporting device comprising: a sheet material detecting unit configured to detect a sheet material; and a biasing unit configured to bias the sheet material to be transported with respect to the light transmitting member on the transport path. Sheet material transport device. 3. The sheet conveying apparatus according to claim 2, wherein the urging unit includes a flexible member that presses the conveyed sheet against the light transmitting member. 4. The sheet material conveying apparatus according to claim 1, wherein said sheet material detecting means is a transmission sensor including a light emitting element, a light receiving element, and a reflection plate. 5. A sheet material transport device according to claim 1, further comprising: an image forming unit configured to form an image on a sheet material transported by the sheet material transport device. Image forming apparatus.