JP2002226086A - Sheet detecting device, sheet supply device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet detecting device capable of securely detecting the sheet condition with the simple structure independently of kind of sheet, and to provide a sheet supply device and an image forming device provided with the same. SOLUTION: An actuator 101 is arranged so that when any one of a first abutment part 101a and a second abutment part 101b abuts on a sheet in a sheet carrying passage, both of the first abutment part 101a and the second abutment part 101b are moved in the abutting direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet detecting device for detecting a state of a sheet in a conveying path, a sheet feeding device for feeding a sheet to another device, and a sheet detecting device and a sheet feeding device. The present invention relates to an image forming apparatus including the device.

[0002]

2. Description of the Related Art Generally, an image forming apparatus such as a printer is provided with a paper sensor for detecting the presence or absence of paper in a paper feed tray or a paper feed cassette for feeding paper. Also, inside the image forming apparatus, a sheet leading edge sensor for aligning the start position of image formation on the sheet, a sheet position sensor for controlling a drive system in the image forming apparatus according to the sheet position, and a sheet inside the image forming apparatus. Various paper sensors, such as a jam sensor for detecting a paper jam, are provided.

[0003] Such a paper sensor usually comprises an actuator that swings or moves forward or backward depending on the presence or absence of contact with the sheet, and a sensor unit such as an optical sensor that detects the swing or forward or backward movement of the actuator. .

[0004]

However, in this type of paper sensor, as shown in FIG. 11, when a paper provided with a perforation for a tractor feeder, such as a tack paper or a continuous form paper, is fed, the perforation is reduced. When the hole reaches the actuator position, the actuator tip gets into the perforation hole,
There is a problem that the absence of paper is erroneously detected despite the presence of paper. In this case, in the image forming apparatus, the image formation is interrupted in the middle, and it is troublesome that unnecessary error processing is required.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has a simple structure capable of always and surely detecting a sheet state irrespective of a sheet type, and a sheet detecting apparatus. An object of the present invention is to provide a sheet feeding apparatus and an image forming apparatus having such a sheet detecting device.

[0006]

According to a first aspect of the present invention, there is provided a sheet detecting apparatus, comprising: an actuator movable by contacting the sheet in a sheet conveying path; A detection unit for detecting an operation of the actuator due to contact with the sheet, wherein the actuator has a first contact unit that contacts the sheet, and a first contact unit that contacts the sheet. A second contact portion which is separated by a predetermined distance in parallel with the width direction of the sheet, and when one of the first contact portion or the second contact portion contacts the sheet and moves, the other also moves. And a connecting part for connecting the first contact part and the second contact part.

In the sheet detecting apparatus according to the first aspect of the present invention, the actuator which is a member abutted on the sheet for detecting a sheet state such as the presence or absence of the sheet in the sheet conveying path is provided. The detector operates by receiving an external force by contacting the sheet in the path, and the detector detects the operation of the actuator. Here, the contact portion that contacts the seat of the actuator includes a first contact portion and a second contact portion. The positional relationship between the first and second contact portions is separated by a predetermined distance in parallel with the width direction of the sheet, and both are connected by the connection portion. Therefore, the operation of the actuator caused by the contact of the sheet is performed by moving one of the first contact portion and the second contact portion while contacting the sheet and moving the other. In addition, the sheet detection device of the present invention is configured such that the sheet detection device is disposed at any position of the sheet conveyance path from the supply side loading section for loading sheets before use to the discharge side loading section for discharging and stacking used sheets. Be placed.

According to a second aspect of the present invention, there is provided a sheet feeding apparatus provided with the sheet detecting apparatus according to the first aspect, wherein a sheet receiving member for receiving the sheet and a sheet on the sheet receiving member are provided. A supply unit for unloading, wherein the sheet receiving member is provided with a concave portion or a hole at a position corresponding to the first and second abutting portions, respectively, and the detecting unit includes the first and second contact portions. When the contact portion is located in the concave portion or the hole portion, the absence of the sheet is detected.

In the sheet feeding apparatus according to the second aspect having the above-described configuration, the feeding section unloads the sheet from the sheet receiving member in order to feed the sheet to another apparatus. The sheet receiving member is provided with a concave portion or a hole at a position corresponding to the first and second contact portions, respectively.
When the sheet is received by the sheet receiving member, the recess or the hole is covered and hidden by the sheet, but is exposed to the outside when the sheet is not received by the sheet receiving member. Detects the absence of the sheet when the first and second contact portions are located in the recesses or holes.

According to a third aspect of the present invention, in the sheet detecting apparatus according to the second aspect, the sheet supply unit includes:
A supply roller having a paper conveyance surface with a high coefficient of friction on its surface and rotatably supported is provided, and the actuator includes:
It is characterized by being arranged at a position near the supply roller.

According to the sheet detecting device of the third aspect having the above-described structure, the first contact portion and the second contact portion are arranged at positions near the supply roller.

According to a fourth aspect of the present invention, there is provided an image forming apparatus including the sheet detecting device according to the first aspect, wherein an image forming process is performed based on a state of the sheet detected by the detecting unit. And a control means for notifying the user or notifying the user.

In the image forming apparatus according to the fourth aspect of the present invention, the control means stops the image forming process or notifies the user based on the state of the sheet detected by the detecting section by the operation of the actuator. I do.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention and typical examples thereof will be described with reference to the drawings. Embodiment 1 A sheet detection device according to a first embodiment of the present invention will be described with reference to FIGS. The sheet detection device of this embodiment is similar to the other embodiments described below, for example, a supply-side paper out sensor, a supply-side paper amount detection sensor, a cue sensor, a jam sensor, and a discharge-side paper amount detection. The present invention can be applied to a sheet supply device used as an image forming apparatus or an optional external device of the image forming apparatus, such as a sensor, or a sheet cassette mounted on these devices.

In the first embodiment of the present invention, as shown in FIG. 1, an actuator 101 movable by contact with a sheet in a sheet conveyance path and an operation of the actuator 101 by contact with the sheet are detected. Detector 1
02, wherein the actuator 101 comprises: a first contact portion 101a contacting the sheet;
A second contact portion 101b separated from the first contact portion 101a by a predetermined distance in parallel with the sheet width direction;
A connecting portion 101c connecting the first contact portion 101a and the second contact portion 101b such that when one of the first contact portion 101a and the second contact portion 101b contacts the sheet and moves, the other also moves. It has.

In the sheet detecting device of this embodiment,
When one of the first contact portion 101a and the second contact portion 101b contacts the sheet in the sheet conveyance path, both the first contact portion 101a and the second contact portion 101b are actuated. It is arranged to be moved in the direction of contact. Specifically, the actuator 1
01 is a direction which is rotatably supported about a predetermined rotation center axis or intersects the sheet surface by a guide means such as a predetermined guide groove (more preferably, a direction substantially parallel to the normal direction of the sheet surface). ), The actuator 101 is free to reciprocate, and is free (there is no sheet) by the weight of the actuator 101 or a biasing means (for example, an elastic body such as a coil spring, a leaf spring, or rubber) that is appropriately used. )
, The first contact portion 101a and the second contact portion 101b are disposed at predetermined positions.

The detecting section 102 is a sensor for detecting that the actuator 101 has moved, and includes an optical sensor, a magnetic sensor, a mechanical switch, and the like.

According to the sheet detecting apparatus of the present embodiment having the above-described structure, as shown in FIGS.
When one of the contact portion 101a and the second contact portion 101b contacts the sheet, the first contact portion 101a and the second contact portion 1
Both 01b move in a direction intersecting the sheet surface (more preferably, a direction substantially parallel to the normal direction of the sheet surface) according to the state of the sheet, for example, the presence or absence and amount of the sheet (in FIG. 2, 3 shows that the actuator 101 is rotating around the connection portion 101c by the contact of the sheet P. In Fig. 3, the actuator 101 moves upward in the drawing by the contact of the sheet P. Is shown). Here, as shown in the drawing, even if a conveyance hole is provided at a position corresponding to one of the first contact portion 101a and the second contact portion 101b of the sheet P, the other will contact the sheet surface, It is possible to prevent a detection error that the sheet absence detection is performed despite the presence of the sheet P. (Embodiment 2) As shown in FIG. 1, a sheet detecting device according to a second embodiment of the present invention includes the actuator 101 in the sheet detecting device according to Embodiment 1 described above.
A thin plate-shaped first actuator 101d having a first abutment portion 101a at a substantially distal end thereof, and an outer shape of the first actuator 101d having substantially the same shape in a side view, and a second abutment portion 101b at a substantially distal end thereof. And a thin plate-shaped second actuator 101e having

According to the sheet detecting apparatus of the present embodiment having the above-described structure, the sheet detecting apparatus operates in the same manner as the sheet detecting apparatus of the first embodiment, and further, has the first contact portion 101a or the second contact portion 10a.
The actuator 101 is formed very easily so that when one of the members 1b contacts the sheet and moves, the other also moves. Therefore, it is possible to supply a suitable sheet detecting device that operates reliably at low cost.

Further, as a preferred configuration example when the actuator 101 in the present embodiment is used, a substantially conical end portion of the first actuator 101d and a substantially conical end portion of the second actuator 101e are arranged in a free state in a sheet conveying path. Opening 10 provided in wall 103 constituting
4 is located inside.

The wall body 103 is made of, for example, a sheet metal processing member or a resin injection molding member that forms the apparatus frame, a metal or resin plate-like member that forms a paper pressing plate of a paper tray or paper guide, or a paper cassette, or the like. Be composed.

Here, if the portion of the sheet transport path where the sheet detecting device is disposed is a sheet supply cassette or a sheet supply tray, the wall 103 is provided with a sheet pressing plate (bottom plate) of the sheet supply cassette. And the paper supply tray body. In this case, the sheet P corresponds to the wall 103 in FIG.
When there is no sheet P, as shown in FIG.
1a and the second contact portion 101b are both surrounded by the opening 104, but when the sheet P is stacked,
The first contact portion 101a and the second contact portion 101b both move to positions outside the position surrounded by the opening 104.

When the portion of the sheet conveying path where the sheet detecting device is disposed is a sheet guide in the image forming apparatus, the wall 103 constitutes a flat sheet guide body. In this case, since the sheet P passes under the wall 103 in FIG.
Although the first contact portion 101a and the second contact portion 101b are moved slightly upward in FIG.
It will be located inside.

According to this configuration example, the size of the opening 104 can be made as small as possible, so that the strength and rigidity of the wall 103 in the portion where the opening 104 is formed does not decrease. Third Embodiment As shown in FIG. 1, a sheet detecting device according to a third embodiment of the present invention is the same as the sheet detecting device according to the first or second embodiment, except that the connecting portion 101c is provided.
Is constituted by a shaft portion extending in the width direction of the sheet and rotatably disposed, and comprises a first contact portion 101a and a second contact portion 1a.
01b is provided at a predetermined distance from the rotation center axis of the shaft portion.

According to the sheet detecting device of the present embodiment having such a configuration, it operates in the same manner as the sheet detecting devices of the first and second embodiments, and further has the first contact portion 101a and the second contact portion 1
01b is formed at an equal distance from the rotation center axis of the connection portion 101c, and the actuator 110 is configured such that the sheet comes into contact with the first contact portion 101a or the second contact portion 101b so that the rotation center axis is centered. To rotate. That is,
Since the first contact portion 101a and the second contact portion 101b are formed at the same distance from the rotation center axis of the connection portion 101c, even when a thin sheet having a small step due to the presence or absence of the sheet is used, the sheet state is maintained. Can be reliably detected. Also, the intended purpose can be achieved with a very simple and reliable operation structure in which the shaft portion is rotatably supported. Embodiment 4 As shown in FIG. 1, a sheet detecting device according to a fourth embodiment of the present invention is the sheet detecting device according to any one of Embodiments 1 to 3, wherein the actuator 101 is integrally formed. Have been. That is,
A first contact portion 101a of the actuator 101;
The second contact portion 101b and the connection portion 101c are, for example,
It is formed by injection molding of a synthetic resin.

According to the sheet detecting device of this embodiment having the above-described configuration, the sheet detecting device operates in the same manner as the sheet detecting devices of the first to third embodiments, and further, as described above, the first contact portion 101a and the second contact portion. When one of the first contact portion 101a or the second contact portion 101b moves in contact with the sheet while the portion 101b is arranged at a predetermined interval in parallel with the width direction of the sheet, the other actuator also moves. Can be realized at a low cost by a simple manufacturing method. In addition, since the actuator 101 is not divided into a plurality of parts and is formed integrally, it is possible to prevent troublesome handling in assembling the sheet detecting device. Embodiment 5 As shown in FIGS. 4 and 5, a sheet feeding device according to a fifth embodiment of the present invention includes the sheet feeding device provided with the sheet detecting device according to any one of Embodiments 1 to 4. The apparatus includes a sheet receiving member 110 for receiving a sheet, and a supply unit 112 for unloading the sheet on the sheet receiving member 110, wherein the sheet receiving member 110 has a first contact part 101a And a concave portion or a hole portion is provided at a position corresponding to the second contact portion 101b, and the detecting portion 102 detects when the first contact portion 101a and the second contact portion 101b are located in the concave portion or the hole portion. It is configured to detect the lack of the sheet.

That is, the wall 103 in FIG. 1 constitutes the sheet receiving member 110, and the opening 104 in FIG. 1 constitutes the opening of the concave portion or the hole in this embodiment.

According to the sheet feeding apparatus of the present embodiment having the above-described configuration, the operation of the sheet detecting apparatus of the first to fourth embodiments allows the use of a perforated sheet such as tack paper or continuous paper as shown in the drawing. Even if there are other devices (for example,
It is possible to always supply a stable sheet to the image forming unit in the image forming apparatus. (Sixth Embodiment) As shown in FIGS. 4 and 5, a sheet feeding device according to a sixth embodiment of the present invention is the sheet feeding device according to the fifth embodiment described above.
A supply roller 112a having a paper conveyance surface with a high coefficient of friction on its peripheral surface and rotatably supported by a shaft is provided, and the actuator is disposed at a position near the supply roller 112a.

According to the sheet feeding apparatus of this embodiment having the above-described structure, the sheet feeding apparatus of the fifth embodiment operates in the same manner as the sheet feeding apparatus of the fifth embodiment. Depending on the surface, the sheet is reliably conveyed. The actuator 101 is arranged at a position near the supply roller 112a. Therefore,
Since the first contact portion 101a and the second contact portion 101b are disposed near the position where the sheet is conveyed, stable sheet supply can be performed even when the sheet size is small. Done. (Seventh Embodiment) A sheet feeding device according to a seventh embodiment of the present invention is the same as the sheet feeding device according to the sixth embodiment, as shown in FIG. The contact portion 101b is disposed on both sides of the supply roller 112a.

According to the sheet feeding apparatus of this embodiment having such a configuration, the sheet feeding apparatus operates in the same manner as the sheet feeding apparatuses of the fifth and sixth embodiments, and the first contact portions 101a and the first contact portions 101a are located near both sides of the supply roller 112a. Since the second contact portion 101b is disposed, stable sheet supply is performed even when the sheet size is small. (Embodiment 8) An image forming apparatus according to an eighth embodiment of the present invention is an image forming apparatus including the sheet detecting device according to any one of Embodiments 1 to 4, wherein the detecting unit 102 Control means C for stopping the image forming process or notifying the user based on the detected sheet state
(See FIG. 6). The control unit C is connected to a detection unit 102 that detects the operation of the actuator 101, and based on detection information from the detection unit 102, various processes required in the image forming apparatus (for example, a sheet conveyance process and an image formation process). , Jam processing, etc.).

According to the image forming apparatus of the present embodiment having such a configuration, appropriate device control is performed irrespective of the type of sheet by the operation of the sheet detecting device of the first to fourth embodiments. (Embodiment 9) An image forming apparatus according to a ninth embodiment of the present invention is an image forming apparatus including the sheet feeding device according to any one of Embodiments 5 to 7, wherein the detecting unit 102 Control means C for stopping the image forming process or notifying the user based on the detected sheet state
(See FIG. 6). The operation of the control means C in this embodiment is the same as in the eighth embodiment.

According to the image forming apparatus of the present embodiment having the above-described configuration, appropriate device control is performed irrespective of the type of sheet by the operation of the sheet supply device of the fifth to seventh embodiments.

[0033]

FIG. 6 is a sectional side view showing a main part of an embodiment of a laser printer as an image forming apparatus according to the present invention. FIG.
, The laser printer 1 includes a feeder unit 4 for supplying paper 3 as a sheet, an image forming unit 5 for forming a predetermined image on the supplied paper 3, and the like in a main body casing 2. I have. In addition, the laser printer 1 includes a control circuit C that controls the entire apparatus and functions as a control unit in the eighth and ninth embodiments.

The feeder unit 4 includes the main casing 2
And a second feeder unit 7 as a sheet feeding device provided on the side of the main body casing 2 and used for manual feeding.

The first paper feed tray 6 has a paper pressing plate 10 on which the paper 3 is stacked and a paper feed roller for feeding the uppermost paper 3 stacked on the paper pressing plate 10. 11 are provided. The paper pressing plate 10
An end remote from the paper feed roller 11 is swingably supported, and an end near the paper feed roller 11 is urged toward the paper feed roller 11 by a spring (not shown). for that reason,
The paper 3 on the top of the paper pressing plate 10 is
1 and is fed one by one by the rotation of the feed roller 11. The second feeder unit 7
Will be described in detail later.

The fed paper 3 is conveyed to a registration roller 14 by a pair of feed rollers 12 and 13 provided near a paper feed roller 11. Registration roller 1
Reference numeral 4 denotes a pair of rollers for feeding the sheet 3 conveyed from the feed roller 13 to the image forming unit 5 after a predetermined registration. A cue sensor 8 for detecting whether or not the leading end of the paper 3 has reached the registration roller 14 is provided upstream of the registration roller 14 in the transport path of the paper 3.

The image forming unit 5 includes a scanner unit 15, a developing unit 16, a fixing unit 17, and the like.

The scanner unit 15 is provided at an upper portion in the main body casing 2 and includes a laser light emitting unit, a polygon mirror, a plurality of lenses, a reflecting mirror, and the like (not shown). Then, a laser beam based on predetermined image data emitted from the laser emitting unit is passed or reflected via a polygon mirror, a reflecting mirror, and a lens, and a developing unit 16 disposed below the scanner unit 15 is provided.
Irradiation is performed on the surface of the photosensitive drum 23 by high-speed scanning.

The developing unit 16 includes a drum cartridge 21 and a developing cartridge 22 which are detachably mounted on the main casing 2. The drum cartridge 21 is provided with a photosensitive drum 23 and a scorotron-type charger (not shown) for charging the surface of the photosensitive drum 23. The developing cartridge 22 is provided with a toner container, a developing roller, a supply roller, a layer thickness regulating blade, and the like, which are not shown.

When the toner accommodated in the toner accommodating portion is supplied to the developing roller by the rotation of the supply roller, the supplied toner is fixed by a layer thickness regulating blade by the rotation of the developing roller. It is carried on the developing roller as a thin layer of thickness. On the other hand, when the surface of the photosensitive drum 23 is uniformly charged by the scorotron-type charger, the surface is then exposed by high-speed scanning of a laser beam from the scanner unit 15, and an electrostatic latent based on predetermined image data is obtained. An image is formed. Then, by the rotation of the developing roller, when the toner carried on the developing roller comes into contact with and contacts the photosensitive drum 23, an electrostatic latent image formed on the surface of the photosensitive drum 23, that is, uniformly, The charged surface of the photosensitive drum 23 is supplied to a portion of the surface of the photosensitive drum 23 which has been exposed to a laser beam and has a reduced potential, and is selectively carried to form a visible image.

Below the photosensitive drum 23, a transfer roller 24 facing the photosensitive drum 23 is rotatably disposed. Therefore, the visible image carried on the photosensitive drum 23 is transferred to the sheet 3 while the sheet 3 passes between the photosensitive drum 23 and the transfer roller 24.

The fixing unit 17 is disposed on the downstream side of the developing unit 16 and includes a heating roller 25 and a heating roller 2.
5. The pressing roller 26 pressed by the pressure roller 5, and the heating roller 25 and the pressing roller 26 provided downstream of the pressing roller 26
A pair of transport rollers 27 are provided. The heating roller 25
A metal halogen lamp for heating is provided, and the toner transferred onto the sheet 3 in the developing unit 16 is thermally fixed while the sheet 3 passes between the heating roller 25 and the pressing roller 26, Thereafter, the paper 3 is transported by the transport rollers 27 to a pair of discharge rollers 28. Paper 3 sent to a pair of discharge rollers 28
Is discharged onto a discharge tray 29 by the discharge roller 28.

A single motor (not shown) is provided in the main body casing 2, and the drive from this motor is supplied to the sheet feed roller 11 and the feed roller 12 via a gear transmission mechanism (not shown). The rollers are transmitted to the feed roller 13, the registration roller 14, the transfer roller 24, and the like, and a driving gear 55 described later, and these members are driven by one motor.

Next, a specific configuration of the second feeder unit 7 in this embodiment will be described with reference to FIGS.

Then, the second feeder unit 7
As shown in FIG. 8, a tray main body 31 on which the paper 3 is stacked in a stack, a paper feed roller 32 as a supply roller for feeding the paper 3, and a tray main body 31 in the paper feed direction of the paper 3. A swinging pressure plate 33 serving as a sheet receiving member for allowing the paper feed roller 32 to pick up the uppermost paper 3 stacked on the tray main body 31 and interposed between the paper feed roller 32 and A cover 72 having a built-in sheet detecting device and a frame 71 for supporting these members are provided.

The tray body 31 is arranged along the longitudinal direction of the second feeder unit 7, and a swing pressing plate 33 is arranged at the tip side (upstream in the direction of feeding the paper 3). As shown in FIG. 8, the swing pressing plate 33 has a plate shape having a substantially U-shaped cross section, and its rear end (downstream side in the supply direction of the paper 3) swings through the swing arm 34. Moving shaft 35
Swingably supported by Therefore, the leading end of the swing pressing plate 33 can swing vertically between a sheet feeding position close to the sheet feeding roller 32 and a standby position separated from the sheet feeding roller 32. . A spring is attached to the tip of the swing pressing plate 33, and the spring is always urged upward by the spring.

The paper feed roller 32 has a substantially circular cross section, and is disposed at the tip end of the swinging pressure plate 33.
When the leading end of the swinging press plate 33 is located at the sheet feeding position, the sheet 3 at the uppermost position of the swing press plate 33 is picked up. A separation pad 37 is provided at a position facing the lower side of the paper feed roller 32, and the paper 3 to be fed is separated from the separation pad 37 by the paper feed roller 3.
2 so that the sheet is fed one by one. That is, the separation pad 37 is provided at the other end of the swinging plate member 39 whose one end is pivotally supported by the swinging shaft 38 below the swinging pressing plate 33, and from the back side thereof. , And is biased toward the paper feed roller 32 by a spring 40. Thus, the paper 3 picked up by the paper feed roller 32 is fed while being separated one by one. Further, the paper feed roller 32 is connected to the second feeder unit 7.
Are arranged at substantially the center in the longitudinal direction.

In the second feeder unit 7, each time the sheet 3 is fed, the swing pressing plate 33 moves from the standby position to the supply position, and the swing pressing plate 33
Is configured to start rotating the paper feed roller 32 when is moved to the supply position.

Here, the swing pressing plate 33 is provided with a pair of openings 104. This opening 104 is
With respect to the longitudinal direction of the feeder unit 7,
Are disposed close to each other with both ends thereof interposed therebetween. That is, FIG.
Is located closer to the outside than the left end of the feed roller 32, and the right opening 104 is
Is disposed closer to the outside than the right end of the paper feed roller 32.

As shown in FIG. 10, the cover 72 is provided with a sensor unit 75 having the actuator 101 shown in FIG. The sensor unit 75 includes an actuator 101, a detection unit 102, and a link 77. Here, FIG. 10A is a view of the cover 72 with the sensor unit 75 mounted, viewed from below, and FIG.
(C) is a cross-sectional view of a portion including the sensor unit 75.

The actuator 101 includes a first contact portion 10
A first actuator 101d having the first contact portion 1a at a substantially front end portion (lower end portion) and a second contact portion 101b having a substantially front end portion (lower end portion)
Actuator 101e, a connecting portion 101c which is a shaft-like member connecting the first actuator 101d and the second actuator 101e, and a connecting portion 10c.
The first actuator 101d comprises a shaft portion 101f provided at both ends of the shaft 1c and an elongated hole 101g provided in the first actuator 101d. The first actuator 101d has a long hole 10
Except for the formation of 1 g, the second actuator 101e has substantially the same shape as the second actuator 101e.

The shaft portion 101f and the connection portion 101c are connected to the first
Actuator 101d and second actuator 101
e, which are provided at the upper end, and whose central axes are substantially coincident with each other. Then, the actuator 101
The shaft portion 101f is supported by a bearing hole provided in the cover 72 so as to be swingable about the shaft portion 101f. Therefore, the first abutting portion 101a, which is the tip of the first actuator 101d,
The second contact portion 101b, which is the distal end of the second actuator 101e, is disposed at substantially the same distance from the central axis of the shaft portion 101f and the connection portion 101c.

The link 77 is a substantially cylindrical rod-shaped member, and has a first tongue piece 77a and a second tongue piece 77b at both ends. The first tongue piece 77a is a member formed so as to be able to temporarily block the optical path of the detection unit 102 constituted by an optical sensor. The second tongue piece 77b is provided with a protrusion 77c at a substantially distal end thereof. The protrusion 77c engages with the elongated hole 101g of the actuator 101 as shown in FIG. Is converted into rotation of the link 77.

As shown in FIG. 7, when there is no paper (free state), the first actuator 101d and the second actuator
1e, the first contact portion 101a and the second contact portion 1
01b is arranged so as to be surrounded by the opening 104.

Next, the operation of the apparatus of this embodiment having the above configuration will be described.

When no paper is placed on the tray main body 31 and the swinging pressure plate 33 of the second feeder unit 7, as shown in FIG. 8 and FIG.
The first contact portion 101a and the second contact portion 101b are suspended by their own weight while being pivotally supported by the shaft portion 101f.
4. Then, the first tongue piece 77
FIG. 10A shows a state in which the optical path of the detection unit 102 is blocked as shown in FIG.

Here, when a sheet is placed on the tray main body 31 and the swing pressing plate 33 in the second feeder unit 7, the sheet is placed on the first contact portion 101a or the second contact portion 1a.
The actuator 101 rotates counterclockwise in FIG. 8 around the shaft portion 101f by contacting any one of the actuators 01b. The rotation of the actuator 101 causes the elongated hole 101g to rotate in the clockwise direction in FIG.
The link 77 and the first tongue piece 77a are rotated via 7c,
The optical path cutoff of the detection unit 102 is released.

In the apparatus of this embodiment, even when tack paper or continuous form paper having perforations at both ends and the center of the paper is used, the first abutting portion is attached to the perforated portion of those papers. Even if one of the first contact portion 101a and the second contact portion 101b faces the other, the other can contact the surface of the sheet, so that the absence of the sheet is erroneously detected in spite of the stacked sheets, and the image formation is stopped halfway. The problem of being inevitably prevented.

It is to be noted that the present embodiment can be appropriately changed within a range that does not change the gist of the present invention.
First actuator 101d and second actuator 10
The distance 1e may be adjustable.

The sensor unit 75 of this embodiment is
In addition to the second feeder unit 70, the feeder unit 4
, Or can be appropriately arranged in the other paper transport path of the laser printer 1.

Further, the present invention is not limited to the above-described embodiments and examples, and equivalents and equivalent methods applicable in the practice of the present invention may be appropriately adopted.

[0062]

As is apparent from the above description,
According to the present invention, with a simple configuration, a sheet detection device that can always reliably detect a sheet state regardless of a sheet type, and by including such a sheet detection device, a sheet detection device can be reliably provided regardless of a sheet type. There is an effect that it is possible to provide a sheet supply apparatus capable of performing a proper sheet supply and an image forming apparatus capable of performing appropriate image forming operation control regardless of a sheet type.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an embodiment of a sheet detection device of the present invention.

FIG. 2 is a diagram illustrating an operation state of the sheet detection device according to the embodiment.

FIG. 3 is a diagram illustrating an operation state of the sheet detection device according to the embodiment.

FIG. 4 is a schematic configuration diagram showing one embodiment of a sheet feeding device of the present invention.

FIG. 5 is a schematic configuration diagram showing another embodiment of the sheet feeding apparatus of the present invention.

FIG. 6 is a side sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 7 is a front view of a second feeder unit in the embodiment.

FIG. 8 is a side sectional view of a second feeder unit in the embodiment.

FIG. 9 is a diagram showing a schematic configuration of an actuator in the embodiment.

FIG. 10 is a diagram showing a schematic configuration of a sensor unit as a main part in the embodiment.

FIG. 11 is an explanatory diagram of a conventional sheet detection device.

[Explanation of symbols]

 101 Actuator 101a First contact part 101b Second contact part 101c Connection part 101d First actuator 101e Second actuator 102 Detecting part

Claims (4)

[Claims] 1. A sheet detection apparatus comprising: an actuator movable by contacting the sheet in a sheet conveyance path; and a detection unit configured to detect an operation of the actuator due to contact with the sheet. The actuator includes a first contact portion that contacts the sheet, a second contact portion that is separated from the first contact portion by a predetermined distance in parallel with the width direction of the sheet, and the first contact portion or A connecting portion connecting the first contact portion and the second contact portion such that when one of the second contact portions moves in contact with the sheet, the other moves in the same manner. A sheet detecting device characterized by the above-mentioned. 2. A sheet feeding apparatus provided with the sheet detecting device according to claim 1, comprising: a sheet receiving member for receiving the sheet; and a feeding unit for unloading the sheet on the sheet receiving member. The sheet receiving member is provided with a concave portion or a hole at a position corresponding to the first and second contact portions, respectively. The detecting portion is configured such that the first and second contact portions are the concave portion or the hole portion. A sheet feeding device that detects the absence of the sheet when the sheet is located at 3. The supply section includes a supply roller having a paper conveyance surface with a high coefficient of friction on its surface and rotatably supported by a shaft, and the actuator is disposed at a position near the supply roller. The sheet feeding device according to claim 2. 4. An image forming apparatus comprising the sheet detecting device according to claim 1, wherein the image forming apparatus stops the image forming process or notifies the user based on a state of the sheet detected by the detecting unit. An image forming apparatus having control means for performing the control.