JPH11255375A - Sheet conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device of such a structure that a sensing device is installed on a sheet conveying path for sensing existence of any sheet of paper, in which a sheet guide part is furnished on a lower guide plate in such a way as corresponding to the swinging range of a sensor arm so that the guidance of each sheet and its sensing operation are performed in good condition. SOLUTION: The sheet conveying path 1 of a sheet conveying device has an upper guide plate 2 and a lower guide plate 3, wherein the body 11 of a sensing device 10 is installed on the upper guide plate 2 while a sensor arm 12 is swingably installed in such a way as directed to the lower guide plate 3. On the surface of the lower guide plate 3, a sheet guide part 15 is installed as mating with the sensor arm 12, and sheet sensing is performed in the condition that the sheet curved by a rib member is being transported. Thus the swinging angle of the sensor arm 12 is set great, and guidance is conducted in such a way that a curved sliding part 13 does not pierce or damage the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting the passage of a sheet disposed in a sheet conveying path of an image forming apparatus and, more particularly, for guiding an arm (a swing arm or an actuator) of the sensor. In addition, the present invention relates to a sheet conveying device provided with means for preventing sheets from being locked in holes or the like provided in a guide plate.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a facsimile machine, a sheet conveying path is formed between two guide plates disposed opposite to each other, and a sheet conveying path is detected in order to detect the passage of the conveyed sheet. The sensor is located. If a photosensor is used as the sensor, a malfunction may occur due to dust or the like. Therefore, a sensor provided with a sensor arm that is swung by the passage of a sheet is generally used. The sensor is mounted on one of the guide plates, and a sensor arm traverses the sheet conveying path in the thickness direction, and a guide hole, a notch, or a concave portion provided on the other guide plate (hereinafter, collectively referred to as these). (Referred to as “opening”). When the sheet passes, the detection mechanism of the sensor body detects that the sensor arm swings greatly, and outputs a signal indicating the passage of the sheet.

[0003]

In the sheet detecting means of the conventional image forming apparatus, the sensor arm projects toward an opening provided in the guide plate in a state of being biased by its own weight or a spring. That is, each time a sheet passes, an effect of pressing the sheet toward the opening is given by the sensor arm. However, the configuration of the swing range of the sensor arm may not be constant due to the manufacturing accuracy of the parts such as the detection device and the guide plate, and the interval of the paper conveyance path of the paper detection unit may vary. There is a problem such as detection.

In an apparatus using long paper, such as a facsimile apparatus, a recording paper is prepared, an extra feeding operation is performed for a predetermined length, and then the recording paper is cut by a cutter to discharge the recording paper. Means for performing an operation of rewinding the remaining paper and positioning the leading end of the remaining paper with respect to the recording unit is used. However, when the paper is pulled back, the tip of the sensor arm may swing in the return direction due to friction with the paper, and the sensor arm pushes the paper toward the opening provided in the guide plate. Pressing state may occur. If the paper is jammed in the opening, it may cause a jam in the paper transport path, and may cause an inconvenience such as an operator having trouble removing the paper.

The present invention solves the above-mentioned problems of the conventional sheet detecting device, and can perform a detecting operation on a sheet passing through a sheet conveying path satisfactorily. It is an object of the present invention to provide a device which is not pushed into a device.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a detection device which uses a sensor arm which is arranged in a paper transport path and is swung by the passage of a paper. The invention of claim 1 of the present invention
A projection is provided which extends to both sides in the sheet transport direction with respect to the opening into which the tip of the sensor arm enters. Therefore, the sensor arm can be reliably swung within the range of the predetermined angle, so that the detection operation by the sensor can be performed accurately, malfunction can be prevented, and jam can be prevented.

According to a second aspect of the present invention, the protrusion has a gentle slope in the sheet conveying direction. Since the paper is guided along the inclined portion, it is possible to prevent the occurrence of troubles such as the paper being caught on the guide portion. The invention according to claim 3 is characterized in that the protrusions provided for the opening are provided at symmetrical positions on both sides in the width direction of the sheet. Therefore, the stress when the paper conveyed in the paper conveyance path hits the protrusion can be set in a well-balanced manner around the arm.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet conveying device according to the present invention. In the example shown in FIGS. 1 and 2, the paper transport path 1 formed by the upper guide plate 2 and the lower guide plate 3 is configured as a paper transport path of a facsimile machine, an electrophotographic copying machine, or the like, or a document transport path. In addition, a detecting device 10 is provided to detect the sheet P passing through the sheet conveying path 1. The detection device 10
Has a sensor arm 12 swingably provided on a sensor main body 11 via a support shaft. A curved sliding portion 13 is provided at a tip end of the sensor arm 12, and the sensor arm 12 is moved to a state where paper is returned. In such a case, the curved sliding portion 13 is configured to slide on the sheet. Further, the sensor main body 11 is formed as a magnet switch type device, which detects passage of a sheet by swinging a sensor arm, or a light emitting element and a light receiving element at a predetermined position in a swing range of the sensor arm. And any other type of detection device such as a device configured to detect the interruption of the optical path due to the swing of the sensor arm.

In the paper transport path in which the detection device 10 is arranged, the sensor main body 11 is fixedly arranged on the upper guide plate 2 and the curved sliding portion 13 at the tip of the sensor arm 12 supported by the sensor main body 11 is moved downward. It is arranged so as to be in contact with the upper surface of the guide plate 3. In this embodiment, the paper guides 15 provided on the lower guide plate 3 have rib members 16 and 1 on both sides of the swinging portion of the sensor arm in a direction parallel to the paper moving direction.
7 are arranged in parallel, between the two rib members,
The curved sliding portion of the sensor arm forms a swingable groove 18. The guide surface of the sheet on the surface of the rib member is formed as a curved surface, and when the sheet moving along the sheet conveying path is curved along the curved surface of the rib member, the sensor arm is swung. To accurately detect the sheet. Further, a concave portion 19 is formed in the groove portion 18 formed between the two curved sliding portions, and a space is provided along the concave portion 19 so that the curved sliding portion can largely swing. Alternatively, the swingable angle of the sensor arm 12 may be set to a large value so that the sheet detecting operation can be performed well.

In the detection device 10 disposed in the paper guide section 15, the paper P passing through the paper transport path 1 is curved while riding on the rib member, and as shown in FIG. Is swung at a large angle as shown by the dashed line in the figure, and the sensor body 11 outputs a signal indicating that the sheet has passed. Further, as in the case of recording paper conveyance of a facsimile machine or the like, when the curved sliding portion 13 of the sensor arm is on the paper when passing through the detecting unit, the advanced portion is cut, and Is returned, the tip of the sensor arm is prevented from piercing the sheet. That is, even if a force for bending the paper between the rib members acts due to the weight of the sensor arm, the distance between the two rib members corresponds to the width of the sensor arm. The pressed paper is prevented from falling into the groove. Further, the portion of the sensor arm that comes into contact with the paper is the curved sliding portion 13 formed as a curved surface, and slides the paper on the curved surface. There is no.

In the present embodiment, a notch is provided in the lower guide plate 3 instead of forming a recess in the groove 18 formed between the rib members, and a curved sliding of the sensor arm is provided. It is also possible to constitute so that a part may fall in a notch part. For example, with respect to the example shown in FIG.
If the range is defined as a cutout portion and the opening in which the curved sliding portion falls, the swing angle of the sensor arm can be set very large. When the swing angle of the sensor arm is set to be large, the operation of detecting the swing of the sensor arm by the sensor main body can be easily detected, and when the arm swings, micro vibration (chattering) occurs. In the case where an error occurs, the influence of the vibration can be ignored and the detection operation can be performed accurately.

[0012]

FIG. 3 shows an example in which a detecting device 10 is disposed at a portion where paper is fed from a paper feed tray 5, and a pickup roller 6 and a paper are provided in the same manner as in a general paper feed device. The separating device 7 is used as a device for sending out a sheet. The pickup roller 6 is configured to be able to be separated from and brought into contact with the paper feed tray 5. The pickup roller 6 separates the sheets taken out of the tray one by one by a sheet separation device 7 and moves the sheet toward the sheet transport path 1. X
Transport in the direction. The paper feeding device can be similarly applied to a document conveying path for feeding a document from a document tray, and the detecting device 10 detects the sheet sent from the tray, and uses the detection signal to detect the sheet. It controls the operation of the equipment disposed downstream of the paper transport path.

In the example shown in FIG. 3, the detecting device 10 disposed at the leading end of the paper transport path has the sensor body 11 supported by the upper guide plate 2 as shown in FIG. Are arranged so as to contact the upper surface of the lower guide plate 3. Also, two rib members are arranged corresponding to the swing range of the sensor arm, and
5 to form a portion for detecting a sheet. In the paper feeding device, when a plurality of papers are taken out from the paper feeding tray, when the paper is separated by the paper separating device and only one sheet is fed, a curved sliding portion is formed on the remaining paper. Stops with it on. Therefore, the pickup roller is configured to be capable of being driven to rotate in the reverse direction, and when the pickup roller is driven to rotate in the reverse direction to return the remaining paper to the tray, the arc surface of the tip of the sensor arm 12 slides on the paper. As a result, a stable returning action can be performed.

In the example shown in FIG. 4, there is provided an auxiliary means for preventing the paper sliding on the paper guide from slipping due to resistance when the paper slides over the paper guide. The example of providing is shown. For example, in a paper guide disposed on a lower guide plate of a paper transport path, a detection device is disposed with respect to the paper guide portion, and a predetermined distance from a central portion in the width direction of the paper. The paper guide unit 15 is arranged in a state where the position is shifted laterally. Therefore, in the example shown in FIG. 4, the sheet guide portion 15 that guides the sheet fed from the tray 5 is disposed on one side with a predetermined distance W from the center line C in the width direction of the sheet conveyance path. The paper guide unit 15 and the detection device are disposed, and the paper guide unit 15
a is arranged.

In the paper guide section 15a, it is not necessary to perform the operation of detecting the paper. Therefore, it is not necessary to arrange the sensor arm. However, when the paper is transported in the paper transport path, 2 provided on the paper guide
The state is such that the resistance when the paper runs over and is curved is uniformly applied to the three rib members. Therefore, as shown in FIG. 4, when the paper guides are disposed on both sides in the width direction of the paper transport path, the paper transported in the paper transport path is obliquely fed by the paper guides. Can be guided so as not to occur.
For example, in an apparatus corresponding to A4 size paper, the paper guide portions 15 and 15a are arranged at equal intervals W with respect to the center portion C in the width direction of the paper. May not necessarily be set to the same value. Therefore, at that time, each sheet guide section may be set within a range in which the skew state of the sheet can be prevented.

Incidentally, the embodiment of the present invention is not limited to the case where the detecting device is arranged in the paper transport path.
The present invention is also applicable to a case where an arbitrary device for detecting the passage of a sheet is arranged in the document conveying path. Further, when the detection device and the paper guide unit are arranged in combination, the detection device can be arranged via the paper guide unit at an arbitrary position on a path for transporting a sheet or a document. Is not particularly limited. Further, in the rib member constituting the paper guide portion, the height of the protruding portion, the width of the groove portion, the shape of the arc surface on which the paper slides, and the like can be arbitrarily set according to the state of the configuration of the paper transport path. It is possible.

[0017]

The paper transport device of the present invention is constructed as described above. Therefore, by providing projections extending on both sides in the paper transport direction with respect to the opening into which the tip of the sensor arm enters. In addition, the sensor arm can be reliably swung within the range of the predetermined angle, and the detection operation by the sensor can be performed accurately, malfunction can be prevented, and jam can be prevented. In addition, since the sheet is guided along the inclined portion by forming a gentle inclined portion in the sheet conveying direction in the projecting portion, it is possible to prevent occurrence of troubles such as the sheet being caught by the guide portion. Further, the projection provided for the opening,
Since it is provided at symmetrical positions on both sides in the width direction of the paper,
The stress when a sheet conveyed in the sheet conveying path hits the protrusion can be set in a well-balanced manner with the arm as a center.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a relationship between a sheet guide unit and a sensor arm according to the present invention.

FIG. 2 is an explanatory diagram of an example in which a detection mechanism is arranged in a paper transport path.

FIG. 3 is an explanatory diagram of an example in which a detection mechanism is arranged at a carry-out portion from a tray.

FIG. 4 is an explanatory diagram of an example in which two paper guide portions are arranged on a lower guide plate.

[Explanation of symbols]

1 paper transport path, 2 upper guide plate, 3 lower guide plate, 5 paper feed tray, 6 pickup roller, 7 paper sorting device, 10 detection device, 1
1 sensor body, 12 sensor arm, 13
Curved sliding part, 15 paper guide part, 16.17
Rib members, 18 grooves, 19 recesses (openings).

Claims (3)

[Claims] 1. A detection device using a sensor arm which is arranged in a paper conveyance path and is swung by passage of a paper, wherein a projection extending on both sides in a paper conveyance direction with respect to an opening into which a tip end of the sensor arm enters. A sheet transport device, comprising a unit. 2. The sheet conveying device according to claim 1, wherein the protrusion forms a gentle slope in the sheet conveying direction. 3. The sheet conveying device according to claim 1, wherein the protrusions provided for the opening are provided at symmetrical positions on both sides in the width direction of the sheet.