JPH1059582A - Sheet material detection device and picture image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet material detection device which has many functions which can detect not only the presence of a sheet material on a sheet material loading base but also a conveyance condition of the sheet material and a picture image formation device. SOLUTION: An actuator 2 as a movable member is supported centered on a shaft part 2c in such a manner that it can turn and has a flag part 2b as a light shade part formed in a fan shape by an arm part 2a. A slit 2d as a light permeation part is formed in the flag part 2b. The actuator 2 receives turn and energizing force in the clockwise direction shown by an arrow mark centered on the shaft part 2c by a return spring 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an apparatus provided with a conveying path and a conveying means for conveying a sheet material, for example, an image forming apparatus such as a copying machine or a laser printer. The present invention relates to a sheet material detecting device for detecting a sheet material.

[0002]

2. Description of the Related Art Heretofore, as this type of sheet material detecting apparatus, for example, a sheet material conveying apparatus of an electrophotographic apparatus as an image forming apparatus such as a copying machine or a laser printer has been used.

An electrophotographic apparatus such as a copying machine or a laser printer will be briefly described.

As is well known, an electrophotographic apparatus transfers desired image information to a sheet (transfer material, photosensitive paper, etc.) which is a sheet material fed into the apparatus by an image forming mechanism in a transfer system or a direct system. A non-fixed toner image is formed and supported in accordance with the method, and the sheet is heated and fixed as a permanently fixed image on the sheet surface by introducing a heat fixing device generally using a heat roller method or a film heating method. And output as an image formed product (copy, print).

When such an electrophotographic apparatus is used, it is necessary for an operator to know whether or not the paper is normally fed and conveyed.

Therefore, first, when there is no paper in the paper feeding section of the apparatus, or when the paper runs out during the paper feeding operation, the paper feeding operation is stopped, and the operator is warned that there is no paper as a warning. I have to tell Therefore, a detection device is arranged in the paper feeding unit to detect whether or not the paper exists.

Further, when a jam (paper conveyance abnormality) occurs during the conveyance of the paper, the conveyance of the paper must be stopped immediately, and the operator must be notified of the occurrence of the jam as a warning. Therefore, in order to detect the occurrence of a jam, a plurality of detecting devices for detecting the arrival of the paper in the paper transport path are arranged, and whether or not the paper has arrived between the respective detecting devices within a predetermined time is detected. Thus, the occurrence of a jam is detected.

[0008]

However, the above-described prior art detecting device of the sheet feeding section, which is a sheet material loading table, has only a function of simply detecting the presence or absence of a sheet.

Therefore, in order to detect whether or not the paper stacked in the paper feed unit has been properly started to be transported and whether or not the paper is being transported in a normal state thereafter, a detection device for the paper feed unit is required. A separate detector had to be provided independently.

Therefore, each detecting device requires an actuator, a sensor, and the like, which not only increases the number of components but also complicates the component configuration and deteriorates the assembly efficiency. In addition, this has unnecessarily increased the cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention not only to detect the presence or absence of a sheet material on a sheet material mounting table but also to detect the state of transport of the sheet material. It is an object of the present invention to provide a sheet material detecting apparatus and an image forming apparatus which are multifunctional to enable the above.

[0012]

In order to achieve the above object, according to the present invention, the presence / absence of a sheet material on a sheet material loading table, and the sheet material loaded on the sheet material loading table are transferred by conveying means. When the sheet material is conveyed, it is possible to detect that the leading end of the sheet material has reached a predetermined position on the conveying path, and that the rear end of the sheet material has passed the predetermined position. .

Therefore, it is detected whether or not the sheet material is properly conveyed, as well as whether or not the sheet material is loaded on the sheet material mounting table.

[0014] Further, a first operation by loading the sheet material on the sheet material loading table, a predetermined position on the transport path when the sheet material loaded on the sheet material loading table is transported by the transport means. The second operation by the sheet material being conveyed, the third operation by the rear end of the sheet material passing through the predetermined position, and the fact that all the sheet materials on the sheet material mounting table have been conveyed A movable member for performing the fourth operation, and detection means for detecting each operation of the movable member.

Therefore, by detecting each operation of the movable member by the detecting means, it is detected whether or not the sheet is loaded on the sheet loading table and whether or not the sheet is properly conveyed. .

[0016] The movable member is rotatably supported by a shaft, and an initial position in an initial state and a sheet material being loaded on the sheet material mounting table, whereby the first member is pressed by a lower surface of the sheet material. The first position rotated by a predetermined angle by the operation described above, and the sheet material loaded on the sheet material loading table is transported by the transport means, so that the second position is pressed by the leading end of the sheet material. The second position rotated by a predetermined angle by the operation may be rotated.

When the sheet material is being conveyed to the predetermined position, the movable member at the second position moves the sheet material to the predetermined position when the remaining sheet material is stacked on the sheet material mounting table. When the trailing edge has passed, the third operation reversely moves to the first position by the third operation, and when the sheet material is the last sheet material loaded on the sheet material loading table, When the rear end of the material has passed the predetermined position, the third operation and the fourth operation may be continuously performed to reversely move to the initial position.

[0018] The detecting means includes a light emitting sensor on one side of a moving area where the movable member moves, and a light receiving sensor capable of receiving light of the light emitting sensor on the other side.
Further, by providing the movable member with a light-shielding portion that shields the light of the light-emitting sensor and a light-transmitting portion that transmits the light, when the movable member is at the initial position, the light-receiving sensor is a light-emitting sensor. The movable member is in a state of directly receiving light,
When the movable member is moved to the first position by the operation described above, the light receiving sensor does not receive light due to the light shielding portion of the movable member, and the movable member is moved from the first position to the second position by the second operation. When the movable member passes through the optical path of the light-emitting sensor, the light-receiving sensor temporarily receives light and then does not receive light, and the movable member is moved by the third operation. When moving from the second position to the first position, the light transmitting sensor of the movable member passes through the optical path of the light emitting sensor, so that the light receiving sensor temporarily receives light and then does not receive light, When the movable member moves from the first position to the initial position by the fourth operation, the light receiving sensor reaches a state of directly receiving the light of the light emitting sensor, and the light receiving signal and the non-light receiving signal of the light receiving sensor Detect changes in By, it detects the operation of each of the movable member.

Accordingly, the state of conveyance of the sheet material or the like is confirmed by detecting each operation.

The detecting means compares the change time from one of the light receiving signal and the non-light receiving signal detected by the detecting means to the other and a predetermined time, so that the sheet material can be conveyed normally. It is desirable to be able to determine whether or not there is.

Therefore, when the operation of the movable member is performed properly, it is determined whether or not the operation is proper by comparing the time when each signal changes from one to the other, and
It is determined whether or not the sheet material conveyance is normally performed.

[0022] The detecting means starts transmitting a signal for starting to convey the sheet material stacked on the sheet material stacking table.
If the signal does not change from the non-light-receiving signal to the light-receiving signal within the first predetermined time, it is determined that the second operation has not been performed normally, and When it is determined that the sheet material conveyance is abnormal, and when the light receiving signal is transmitted by the second operation, the light receiving signal does not further change within the second predetermined time after changing to the non-light receiving signal again. Assuming that the third operation was not performed normally, it may be possible to determine that the sheet material is abnormal during the passage of the sheet material by the detection unit.

Auxiliary detection means for detecting that the sheet material has reached a predetermined position downstream of the detection position by the detection means in the conveyance path where the sheet material is conveyed,
When the detecting means does not detect the arrival of the sheet material by the auxiliary detecting means within a third predetermined time after the light receiving signal is transmitted by the third operation and then changes to the non-light receiving signal again after the change. In this case, it is preferable that the sheet material conveyance abnormality can be determined after the sheet material has passed the detection position by the detection means and before the detection position by the auxiliary detection means.

Further, the above-mentioned sheet material detecting device can be provided in an image forming apparatus for forming image information at a predetermined position on a sheet material conveyed by a conveying means from a sheet material mounting table.

[0025]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) FIGS. 1 to 7 show a first embodiment of the present invention.

(1) Brief Description of Image Forming Apparatus The case of an image forming apparatus will be briefly described as an example to which the sheet material detecting apparatus according to the embodiment of the present invention is applied. FIG. 1 is a schematic configuration diagram of the image forming apparatus. The image forming apparatus of the present embodiment is an outline of a copying machine or a laser printer of a transfer type electrophotographic type / process cartridge detachable type.

Reference numeral 31 denotes a rotating drum type electrophotographic photosensitive member which is rotated at a predetermined peripheral speed (process speed) in a clockwise direction indicated by an arrow.

The photosensitive member 31 undergoes a predetermined potential charging process by the charger 32 during the rotation process. Next, the charged surface is exposed to target image information L by exposure means (not shown; slit image projecting means of a document image, laser scanning exposure means, etc.), so that the photoconductor surface corresponds to the target image information. A formed electrostatic latent image is formed. The latent image is developed by the developing device 33 as a toner image.

On the other hand, one sheet (transfer material) as a sheet material is separated and fed from a multi-sheet feeding table 34 as a sheet material stacking table, and passed through a pair of registration rollers 42 as conveying means, and the rotating photoconductor 31 is rotated. The transfer roller 35 is conveyed and introduced into the transfer portion T at a predetermined timing synchronized with the rotation of the photoconductor 31, so that the photoconductor 31 is pressed.
Are sequentially transferred onto the paper surface.
The sheet that has passed through the transfer section T is separated from the surface of the rotating photoconductor 31 and is conveyed and introduced to a heat roller type heat fixing device 36. Then, after undergoing the heat fixing process of the transferred toner image, the transferred toner image is output as a copy or a print to the discharge tray 37.

After the transfer of the toner image onto the sheet, the surface of the rotating photoreceptor is cleaned by a cleaning device 38 to remove residual contaminants such as untransferred toner, and is repeatedly used for image formation.

Reference numerals 39 and 40 denote a paper feed roller 39 and a separation pad 40 which are conveying means of the multi paper feed table 34.

One or a plurality of sheets set on the multi sheet feeding table 34 are separated and fed into one sheet by the rotation of the sheet feeding roller 39 and the separation pad 40. The sheet is conveyed to the transfer section T along the path of the sheet path c.

The sheet is conveyed by the center reference conveyance or the one-side reference conveyance. In the present embodiment, the central reference transport is performed.

Reference numeral A denotes a sheet material detecting device which is installed in the vicinity of a sheet feeding roller and which is a feature of the embodiment of the present invention, and detects the presence or absence of a sheet and detects a jam.

In the image forming apparatus of the present embodiment,
The four process devices of the photoreceptor 31, the charger 32, the developing device 33, and the cleaning device 38 are collectively provided as a process cartridge 41 which can be detachably attached to the image forming apparatus main body.

(2) Description of Configuration of Sheet Material Detecting Apparatus A FIG. 2 is a perspective view of the sheet material detecting apparatus A.

Reference numeral 1 denotes a sensor which constitutes detection means fixedly arranged on the holder. In the present embodiment, a photo interrupter is used. 1a and 1b are a light emitting unit and a light receiving unit of the sensor, respectively. Light emitted from the light emitting section 1a as a light emitting sensor enters the light receiving section 1b as a light receiving sensor through the slit 1c. This optical path is opened or cut off by the swing of the flag portion 2b of the actuator. The sensor light receiving section 1b outputs a high level signal as a light receiving signal when the optical path is open, and outputs a low level signal as a non-light receiving signal when the optical path is interrupted. The signal is output to the control unit in FIG. In FIG. 3, reference numeral 4 denotes a CPU, which is a control unit for performing arithmetic processing; 5, a ROM, in which a control sequence of the image forming apparatus is written; 6, a driver for operating the sensor 1; .

The actuator 2 as a movable member is rotatably supported about a shaft portion 2c, and has an arm portion 2a and a fan-shaped flag portion 2b as a light shielding portion. A slit 2 as a light transmitting part is provided in the flag part 2b.
d is formed. The actuator 2 receives a rotational urging force in the clockwise direction indicated by the arrow around the shaft portion 2c by the return spring 3.

The actuator 2 is installed beside the sheet feed roller so as to act on all sheets conveyed into the apparatus by the center reference conveyance.

In a free state in which no sheet is present, the actuator 2 assumes a rotation angle posture as shown in FIG. 4 as a home position as an initial position.

In this state, the flag portion 2b of the actuator is located above the paper position when the paper is loaded,
The arm portion 2a protrudes upward from below the sheet path a after the sheet is fed. The optical path of the sensor 1 is open,
Is at a high level.

(3) Description of the operation of the sheet material detecting device A a) When the paper P is stacked on the multi-feeding tray The operation state of the device A when the paper P is loaded on the multi-feeding tray is shown in FIG. Shown in

When the sheets P are stacked on the multi-sheet feeding table, the flag portion 2b of the lower surface actuator of the sheets P is pushed downward. Due to the pressing of the lower surface of the sheet P against the flag portion 2b, the entire actuator 2 returns from the home position rotation angle in FIG. 4 around the shaft portion 2c as shown in FIG. To the first position shown in the figure (first operation). The actuator 2 is prevented from returning and rotating until there are no more sheets on the multi-sheet feeding table.

When the actuator 2 rotates counterclockwise, the flag 2b cuts off the optical path of the sensor 1, so that the output signal of the sensor 1 switches from the high level to the low level. When this is detected by the control unit 4 (FIG. 3), it can be understood that the sheets are stacked on the multi sheet feed tray.

B) When the paper P is fed When the paper P is fed, the leading end of the paper P pushes down the arm 2a of the actuator. By pressing the sheet P against the arm 2a, the entire actuator 2 is returned from the state shown in FIG. 5 to the center of the shaft 2c as shown in FIG.
And moves to the second position shown in the figure (second operation). Arm part 2 of actuator 2
The leading end of a is in contact with the back side of the fed paper P, and the return rotation of the actuator 2 is prevented until the paper P has passed.

When the actuator 2 rotates counterclockwise, the slit 2d of the flag 2b passes through the optical path of the sensor 1. The light path is opened only during this passage,
The sensor output signal switches from low level to high level for a moment. When the slit 2d has passed, the optical path of the sensor 1 is again blocked by the flag 2b, and the sensor output signal switches from high level to low level.

When the rear end of the sheet P passes through the arm 2a of the actuator 2, the sheet P rotates clockwise by the spring force of the return spring 3 and moves to the first position again (third operation).

At this time, similarly to the second operation, the slit 2d of the flag portion 2b passes through the optical path of the sensor 1, the sensor output signal switches from low level to high level for a moment, and the slit 2d passes through. And the optical path of the sensor 1 is cut off again by the flag section 2b, and the sensor output signal switches from the high level to the low level.

When the sheet P remains in the multi-sheet feeding table, the actuator 2 stands by at the first position. When the paper P is transported,
The actuator 2 passes through the first position, further rotates clockwise and moves to the initial position again (fourth operation).

FIG. 7 is a graph showing a change in sensor output when the paper P is continuously fed. In the detection cycle of each fed sheet, the first pulse of the output level is the leading edge detection of the sheet, and the second pulse is the trailing edge detection of the sheet.

C) Jam Detection Sensor 1 also functions as a jam detection sensor (detects whether or not sheet material conveyance is normally performed). If the sensor 1 does not output the sheet leading edge detection signal after a predetermined timer time as a first predetermined time from the time when the sheet feeding start signal (sheet material conveyance start signal) is generated from the multi sheet feeding table, the sheet It is determined that the sheet is jammed in the sheet path portion on the upstream side in the sheet conveyance direction from the material detection device A.

If the sensor 1 does not output the trailing edge detection signal after a predetermined timer time as the second predetermined time after the sensor 1 outputs the sheet leading edge detection signal, the sheet material detecting device A It is determined that the paper has jammed over the portion.

Further, when a predetermined timer time as a third predetermined time elapses after the output signal of the sheet trailing edge from the sensor 1 has been output, there is no sheet discharge signal from a sheet discharge detection sensor as auxiliary detection means (not shown). It is determined that the paper has jammed in the sheet path downstream of the sheet material detection device A in the paper transport direction. When a jam is detected, the control unit 4 stops the image forming apparatus in an emergency and activates the jam occurrence display means.

As described above, the sheet material detecting device A can detect the presence or absence of the sheet material on the sheet material mounting table and the conveyance state of the sheet material, and can detect the sheet material conveyance abnormality (jam). . Therefore, the number of parts can be reduced, the configuration is simplified, and the assembling efficiency is increased. This also leads to cost reduction.

(Second Embodiment) FIG. 8 shows a second embodiment of the present invention. In the first embodiment, the return spring 3 is provided on the actuator 2 to obtain the rotation urging force. In the present embodiment, the rotation urging force is obtained by the weight. Other configurations and operations are the same as those of the first embodiment, so that the same components are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, the actuator 2
The return spring 3 is not provided, and a weight 7 is attached to the end of the flag portion so as to assume a rotation angle posture as shown in the free state. As a result, a rotational urging force similar to that of the return spring is obtained.

With the configuration of the present embodiment, the return spring 3 is not required, and the component configuration is simplified as compared with the first embodiment.

(Third Embodiment) FIGS. 9 to 11 show a third embodiment of the present invention. In the above-described first embodiment, the actuator 2 is configured by one component, but in the present embodiment, the actuator 2 is configured by three components. Other configurations and operations are the same as those of the first embodiment, so that the same components are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, the actuator is composed of three parts as shown in FIG. The arm 2a and the flag 2b of the actuator are independent of each other. The two parts are connected by a connecting bar 8. The arm 2a rotates about the shaft 2e. The flag portion has a slit 2d formed in the same manner as in the first embodiment, and receives a biasing force in the clockwise direction indicated by an arrow around the shaft portion 2c by the return spring 3.

In a free state in which no sheet is present, the actuator 2 has a home position in a rotation angle posture as shown in FIG.

In this state, the flag portion 2b of the actuator is above the paper position when the paper is loaded,
The arm portion 2a protrudes upward from below the sheet path a after the sheet is fed. The optical path of the sensor 1 is open,
Is at a high level.

A) When the paper P is stacked on the multi-sheet feeder The operation state of the apparatus A when the paper P is stacked on the multi-sheet feeder is shown in FIG.

When the sheets P are stacked on the multi-sheet feeding table, the flag portion 2b of the actuator is pushed downward. By pressing the paper P against the flag portion 2b, the actuator 2
10 returns from the home position rotation angle in FIG. 9 around the shaft portion 2c and rotates counterclockwise against the spring 3 as shown in FIG. The actuator 2 is prevented from returning and rotating until there are no more sheets on the multi-sheet feeding table.

When the actuator 2 rotates counterclockwise, the flag 2b cuts off the optical path of the sensor 1, and the output signal of the sensor 1 switches from high level to low level. When this is detected by the control unit 4 (FIG. 3), it can be seen that the sheets are stacked on the multi-sheet feeding table.

B) When the paper P is fed When the paper P is fed, the leading end of the paper hits the arm 2a of the actuator and pushes the arm 2a in the paper transport direction. The bar 8 pushes the flag 2b of the actuator 2 by the pressing of the sheet P against the arm 2a. As a result, the flag portion 2b returns from the state shown in FIG. 10 around the shaft portion 2c and rotates counterclockwise against the spring 3 as shown in FIG. The tip of the arm 2a of the actuator 2 is in contact with the back side of the fed sheet P, and the return rotation of the actuator 2 is prevented until the sheet P has passed.

When the actuator 2 rotates counterclockwise, the slit 2 d of the flag 2 b passes through the optical path of the sensor 1. The light path is opened only during this passage,
The sensor output signal switches from low level to high level for a moment. When the slit 2d has passed, the optical path of the sensor 1 is again blocked by the flag 2b, and the sensor output signal switches from high level to low level.

According to the configuration of the present embodiment, the arrangement of the arm 2a for detecting a jam can be changed to the flag 2b.
There is an advantage that the operation can be performed at any position in the sheet transport direction from the position.

(Fourth Embodiment) FIG. 12 shows a fourth embodiment of the present invention. In the first embodiment, the high level signal is output as the light receiving signal when the optical path is opened, and the low level signal is output as the non-light receiving signal when the optical path is cut off. In the present embodiment, the low level signal is output when the optical path is opened. And outputs a high level when the optical path is interrupted. Other configurations and operations are the same as those of the first embodiment, so that the same components are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, when the optical path of the sensor 1 is open, the output signal of the sensor 1 is at a low level as a light receiving signal, and when the optical path is interrupted, 1 is at a high level as a non-light receiving signal.

The operation of the actuator 2 is the same as that of the first embodiment, and a description thereof will be omitted. In the present embodiment, the change of the sensor output is different from that of the first embodiment.

FIG. 12 is a graph showing a change in sensor output when the paper P is continuously fed. In the detection cycle of each fed sheet, the leading edge of the first pulse of the output level is the leading edge of the sheet, and the trailing edge of the second pulse is the trailing edge of the sheet.

With the configuration of the present embodiment, when the sensor 1 fails, the sensor output signal goes low, so that it is determined that no paper is loaded, and no paper feeding operation is performed. Therefore, there is an advantage that the useless feeding operation is not performed, and the durability of the feeding roller 39 and the separation pad 40 is improved.

[0074]

According to the sheet material detecting apparatus described above, it is possible to detect not only whether the sheet material is loaded on the sheet material loading table but also whether the sheet material is properly conveyed. By realizing the function, the number of parts is reduced, and the parts configuration is simplified, and the assembling efficiency is improved.

A sheet material detecting device having a simple configuration is provided by the fact that the sheet material is stacked on the sheet material loading table, and a movable member movable in accordance with the sheet material transport position and a detecting means for detecting the operation of the movable member. Multi-function can be realized.

By comparing the change time of each operation of the movable member by the detection means with a predetermined time,
It can be determined whether or not the sheet material conveyance is normally performed.

By comparing the change time of each operation with the predetermined time, it is possible to specify at which position the sheet material conveyance abnormality has occurred.

Further, the above-described sheet material detecting device can be provided in an image forming apparatus for forming image information at a predetermined position on a sheet material conveyed by a conveying means from a sheet material mounting table.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a perspective view of a main part of the sheet material detecting device according to the first embodiment.

FIG. 3 is a block diagram of a control system.

FIG. 4 is an explanatory diagram of the operation of the sheet material detecting apparatus according to the first embodiment (in an initial state).

FIG. 5 is an explanatory diagram of the operation of the sheet material detecting apparatus according to the first embodiment (at the time of stacking sheets).

FIG. 6 is an operation explanatory diagram of the sheet material detecting apparatus according to the first embodiment (at the time of paper feeding).

FIG. 7 is a diagram showing a form of a sensor output signal of the sheet material detecting device according to the first embodiment.

FIG. 8 is an operation explanatory view (in an initial state) of the sheet material detecting apparatus according to the second embodiment.

FIG. 9 is a diagram illustrating an operation of the sheet material detecting apparatus according to the third embodiment (in an initial state).

FIG. 10 is an explanatory diagram of the operation of the sheet material detecting apparatus according to the third embodiment (at the time of stacking sheets).

FIG. 11 is an explanatory diagram of the operation of the sheet material detecting apparatus according to the third embodiment (at the time of sheet feeding).

FIG. 12 is a diagram showing a form of a sensor output signal of a sheet material detecting apparatus according to a fourth embodiment.

[Explanation of symbols]

 A sheet material detecting device 1 sensor (photo interrupter) 1a light emitting section 1b light receiving section 2 actuator 2a arm section 2b flag section 2d slit 3 return spring 7 weight 8 connecting bar

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeru Okamura 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (9)

[Claims] The presence or absence of a sheet material on a sheet material loading table, and the leading end of the sheet material is positioned at a predetermined position on a transport path when the sheet material loaded on the sheet material loading table is transported by transport means. A sheet material detection device capable of detecting that the sheet material has arrived and that the rear end of the sheet material has passed the predetermined position. 2. A first operation in which a sheet material is loaded on a sheet material loading table, and a predetermined position on a transport path when the sheet material loaded on the sheet material loading table is transported by transport means. The second operation by the sheet material being conveyed, the third operation by the rear end of the sheet material passing through the predetermined position, and the fact that all the sheet materials on the sheet material mounting table have been conveyed A sheet member detection device comprising: a movable member that performs a fourth operation; and detection means that detects each operation of the movable member. 3. The movable member is rotatably supported by a shaft, and has an initial position in an initial state, and a sheet material is loaded on the sheet material mounting table, so that the lower surface of the sheet material is pressed. A first position rotated by a predetermined angle by the first operation, and a sheet material stacked on the sheet material stacking table being conveyed by conveyance means, whereby the first position is pressed by a leading end of the sheet material. 3. The sheet material detecting device according to claim 2, wherein the second position and the second position rotated by a predetermined angle are rotated and moved by the operation of 2. 4. The movable member at the second position while the sheet material is being conveyed at a predetermined position, wherein when the remaining sheet material is stacked on the sheet material mounting table, the movable member is moved to a predetermined position. When the rear end passes through the position, the third operation reversely moves to the first position by the third operation, and when the sheet is the last sheet loaded on the sheet loading table, When the rear end of the sheet material passes through a predetermined position, the third operation and the fourth operation are continuously performed, so that the sheet material reversely moves to the initial position. 3. The sheet material detection device according to 3. 5. The detecting means includes a light-emitting sensor on one side of a moving area where the movable member moves, and a light-receiving sensor on the other side capable of receiving light from the light-emitting sensor. When the movable member is at the initial position, the light-receiving sensor emits light of the light-emitting sensor by providing the movable member with a light-shielding portion that shields light from the light-emitting sensor and a light-transmitting portion that transmits the light. When the movable member moves to the first position by the first operation, the light receiving sensor does not receive light due to the light shielding portion of the movable member, and the movable member is When moving from the first position to the second position by the second operation, the light transmitting sensor of the movable member passes through the optical path of the light emitting sensor so that the light receiving sensor temporarily receives light and then receives light. The movable member is in the third state. When the movable member moves from the second position to the first position due to an operation, the light receiving sensor temporarily receives light and does not receive light after the light transmitting portion of the movable member passes through the optical path of the light emitting sensor. When the movable member moves from the first position to the initial position by the fourth operation, the light receiving sensor reaches a state of directly receiving the light of the light emitting sensor. The sheet material detection device according to claim 4, wherein each operation of the movable member is detected by detecting a change in a light reception signal. 6. The detecting means compares the change time from one of the light receiving signal and the non-light receiving signal detected by the detecting means to the other with a predetermined time, so that the sheet material can be transported normally. The sheet material detecting apparatus according to claim 5, wherein it is possible to determine whether or not the sheet material has been touched. 7. When the detection means does not change from a non-light-receiving signal to a light-receiving signal within a first predetermined time from the time of transmission of a conveyance start signal of the sheet material stacked on the sheet material stacking table. It can be determined that the second operation has not been performed normally and that the sheet material has been conveyed abnormally until the sheet material reaches the detection position by the detection means. If the sheet material does not change to the non-light receiving signal again within the second predetermined time after the transmission of the sheet material, it is determined that the third operation has not been performed normally and the sheet material is detected. 7. The sheet material detecting apparatus according to claim 6, wherein it is possible to determine that the sheet material is transported abnormally while passing the detection position by the means. 8. An auxiliary detecting means for detecting that a sheet material has reached a predetermined position downstream of a detecting position of said detecting means on a conveying path on which the sheet material is conveyed, wherein said detecting means detects said sheet material. If the auxiliary detecting means does not detect the arrival of the sheet material within the third predetermined time after the light receiving signal is transmitted by the third operation and then changes to the non-light receiving signal again, 8. The sheet material detecting apparatus according to claim 7, wherein it is possible to determine that the sheet material has been transported abnormally after passing through the position detected by the detecting means and before the position detected by the auxiliary detecting means. 9. An image forming apparatus for forming image information at a predetermined position on a sheet material conveyed by a conveying means from a sheet material stacking table, wherein the sheet according to any one of claims 1 to 8. An image forming apparatus comprising a material detection device.